JP6957250B2 - Non-aqueous lithium storage element - Google Patents

Description

The present invention relates to a non-aqueous lithium storage element.

In recent years, from the viewpoint of effective use of energy aiming at conservation of the global environment and resource saving, power smoothing system or midnight power storage system for wind power generation, distributed power storage system for home use based on solar power generation technology, power storage for electric vehicles Systems and the like are attracting attention.
The first requirement of the batteries used in these power storage systems is high energy density. The development of lithium-ion batteries is being energetically promoted as a promising candidate for high-energy density batteries that can meet such demands.
The second requirement is that the output characteristics are high. For example, in a combination of a high-efficiency engine and a power storage system (for example, a hybrid electric vehicle) or a combination of a fuel cell and a power storage system (for example, a fuel cell electric vehicle), high output discharge characteristics in the power storage system are required at the time of acceleration. There is.
Currently, electric double layer capacitors, nickel-metal hydride batteries, and the like are being developed as high-power power storage devices.

Among the electric double layer capacitors, those using activated carbon for the electrodes have an output characteristic of about 0.5 to 1 kW / L. This electric double layer capacitor has high durability (cycle characteristics and high temperature storage characteristics), and has been considered to be the most suitable device in the field where high output is required. However, its energy density is only about 1 to 5 Wh / L. Therefore, the electric double layer capacitor needs to be further improved in energy density.

On the other hand, the nickel-metal hydride battery currently used in hybrid electric vehicles has a high output equivalent to that of an electric double layer capacitor and an energy density of about 160 Wh / L. However, research is being vigorously pursued to further increase its energy density and output, as well as to improve its durability (particularly, stability at high temperatures).

In addition, research is underway to increase the output of lithium-ion batteries. For example, a lithium ion battery has been developed in which a high output exceeding 3 kW / L can be obtained at a discharge depth (a value indicating what percentage of the discharge capacity of the power storage element is discharged) of 50%. However, its energy density is 100 Wh / L or less, and the design is such that the high energy density, which is the greatest feature of the lithium ion battery, is intentionally suppressed. Moreover, its durability (cycle characteristics and high temperature storage characteristics) is inferior to that of electric double layer capacitors. Therefore, in order to give the lithium ion battery practical durability, it is used in a range where the discharge depth is narrower than the range of 0 to 100%. Since the capacity of the lithium-ion battery that can be actually used becomes smaller, research for further improving the durability is being vigorously pursued.

As described above, there is a strong demand for practical application of a power storage element having high energy density, high output characteristics, and durability. However, each of the existing power storage elements described above has advantages and disadvantages. Therefore, there is a demand for a new power storage element that satisfies these technical requirements. As a promising candidate, a power storage element called a lithium ion capacitor has attracted attention and is being actively developed.
The energy of the capacitor is represented by 1/2 · C · V2 (where C is the capacitance and V is the voltage).

A lithium ion capacitor is a type of power storage element (non-aqueous lithium type power storage element) that uses a non-aqueous electrolyte solution containing a lithium salt. -A power storage element that charges and discharges by a non-Faraday reaction by desorption and a Faraday reaction by the storage and release of lithium ions at the negative electrode, similar to a lithium ion battery.
To summarize the above-mentioned electrode materials and their characteristics, high output and high durability are achieved when a material such as activated carbon is used for the electrode and charging / discharging is performed by adsorption / desorption (non-Faraday reaction) of ions on the surface of activated carbon. However, the energy density becomes low (for example, it is multiplied by 1). On the other hand, when an oxide or carbon material is used for the electrode and charging / discharging is performed by the Faraday reaction, the energy density becomes high (for example, 10 times that of the non-Faraday reaction using activated carbon), but the durability and output characteristics are increased. There is a problem in.
As a combination of these electrode materials, the electric double-layer capacitor uses activated carbon (energy density 1 times) for the positive electrode and the negative electrode, and charges and discharges both the positive electrode and the negative electrode by a non-Faraday reaction, and has high output and high durability. However, it is characterized by low energy density (1x positive electrode x 1x negative electrode = 1).

The lithium ion secondary battery is characterized by using a lithium transition metal oxide (energy density 10 times) for the positive electrode and a carbon material (energy density 10 times) for the negative electrode, and charging and discharging both the positive electrode and the negative electrode by a Faraday reaction. Although the energy density is 10 times the positive electrode x 10 times the negative electrode = 100, there are problems in output characteristics and durability. Further, in order to satisfy the high durability required for a hybrid electric vehicle or the like, the discharge depth must be limited, and the lithium ion secondary battery can use only 10 to 50% of its energy.

Lithium-ion capacitors use activated carbon (1x energy density) for the positive electrode and carbon material (10x energy density) for the negative electrode, and are characterized by performing charging and discharging by a non-Faraday reaction at the positive electrode and a Faraday reaction at the negative electrode. It is a new asymmetric capacitor that combines the features of a multi-layer capacitor and a lithium-ion secondary battery. It is characterized by having high energy density (1x positive electrode x 10x negative electrode = 10) while having high output and high durability, and it is not necessary to limit the discharge depth unlike a lithium ion secondary battery. be.

Examples of applications of lithium ion capacitors include electric storage for railways, construction machinery, and automobiles. In these applications, the operating environment is harsh, so the capacitors used need to have excellent properties in a wide temperature range from high temperatures above 40 ° C to low temperatures below 0 ° C. In a high temperature environment of 40 ° C. or higher, there is a problem of performance deterioration caused by gas generation due to decomposition of the electrolytic solution. As a countermeasure technology for such problems, an additive is added to the non-aqueous electrolyte solution to form a film composed of its decomposition products on the surface of the negative electrode active material, so that the non-aqueous electrolyte solution will be charged and discharged thereafter. There is a technology to suppress the reduction and decomposition of the battery and improve the durability of the battery. As a technique related to this, Patent Documents 1 and 2 propose a power storage element in which two kinds of additives having different structures are contained in an electrolytic solution. Further, Patent Document 3 proposes a power storage element in which a certain amount of film is formed on the surface of a negative electrode active material by adding an additive to a non-aqueous electrolyte solution.

Further, in a low temperature environment of 0 ° C. or lower, there is a problem that the internal resistance of the power storage element increases, causing a sudden decrease in output.
As a means for solving such a problem, Patent Documents 4 and 5 propose lithium ion capacitors having improved low temperature characteristics by containing a specific solvent in the electrolytic solution. In Patent Document 5, by optimizing the ratio of the mixed solvent in the electrolytic solution and enhancing the compatibility with a specific negative electrode active material, it is possible to improve the low temperature characteristics and suppress the gas generation during the high temperature test. Lithium ion capacitors have been proposed.

In the present specification, the mesopore amount is calculated by the BJH method and the micropore amount is calculated by the MP method. However, the BJH method is proposed in Non-Patent Document 1, and the MP method is "t-". It means a method of obtaining the micropore volume, the micropore area, and the distribution of micropores by using the "plot method" (Non-Patent Document 2), and is shown in Non-Patent Document 3.

Japanese Unexamined Patent Publication No. 2014-27196 Japanese Unexamined Patent Publication No. 2013-206791 Japanese Unexamined Patent Publication No. 2014-137861 Japanese Unexamined Patent Publication No. 2015-70032 Japanese Unexamined Patent Publication No. 2011-258915

E. P. Barrett, L. et al. G. Joiner and P. Hallenda, J. et al. Am. Chem. Soc. , 73,373 (1951) B. C. Lippens, J. et al. H. de Boer, J. et al. Catalysis, 4319 (1965) R. S. Mikhair, S.M. Brunauer, E. et al. E. Bodor, J.M. Colloid Interface Sci. , 26, 45 (1968)

The techniques described in Patent Documents 1 and 2 suppress deterioration of gas and electrodes during high-temperature storage, but do not mention low-temperature characteristics. Patent Document 3 provides a capacitor having excellent cycle characteristics at high temperatures, but Patent Document 3 does not show results regarding changes in characteristics after a high temperature cycle test. Further, the lithium ion capacitors described in Patent Documents 4 and 5 can improve the characteristics of the power storage element at a low temperature, but the effect of improving the durability at a high temperature has not been confirmed. Patent Document 5 provides a lithium ion capacitor in which gas generation during a high temperature test is suppressed in addition to improving low temperature characteristics, but does not mention a change in characteristics after a high temperature test.

As described above, in the conventional lithium ion capacitor, the superiority or inferiority of the conventional lithium ion capacitor is only evaluated by focusing on either the low temperature characteristic or the high temperature durability, and a wide range from high temperature to low temperature, which is important for practical use. The input / output characteristics and durability of the power storage element in the temperature range are not considered. In addition, the life required of a capacitor is 10 to 15 years, and it is important in the actual use of a capacitor that there is little change in characteristics when used for a long period of time in a high temperature environment. It has not been investigated for lithium-ion capacitors.

Therefore, the problem to be solved by the present invention is that both high input / output characteristics in a wide temperature range and excellent high temperature durability can be achieved, and the characteristics can be maintained for a long period of time. It is to provide an aqueous lithium type power storage element.

In the lithium ion capacitor, the present inventors use activated carbon as the positive electrode active material and contain a specific amount of the lithium (Li) compound represented by a specific structural formula in the positive electrode active material layer in a wide temperature range. We have found that it is possible to achieve both high input / output characteristics, gas generation due to decomposition of the electrolytic solution in a high temperature environment, and suppression of characteristic deterioration due to this, and completed the present invention.
That is, the present invention is as follows.
[1]
Positive electrode;
Negative electrode;
Separator; and non-aqueous electrolyte solution containing lithium ions;
It is a non-aqueous lithium-type power storage element containing
The negative electrode has a negative electrode current collector and a negative electrode active material layer containing a negative electrode active material provided on one side or both sides of the negative electrode current collector, and the negative electrode active material occludes lithium ions.・ Including carbon material that can be released
The positive electrode has a positive electrode current collector and a positive electrode active material layer containing a positive electrode active material provided on one side or both sides of the positive electrode current collector, and the positive electrode active material contains active carbon.
Equation CH ₃ OX ¹ {In the equation, X ¹ is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. }, The content of the compound represented by} per unit mass of the positive electrode material layer is defined as A, and the formula C ₂ H ₅ OX ² {wherein X ² is − (O) _n Li or − (COO). _n Li and n is 0 or 1. } When the content of the compound represented by} per unit mass of the positive electrode material layer is B, 1.80 ≦ A / B ≦ 20.00, and
The following formulas (1) to (3):
LiX ^I- OR ¹ O-X ^II Li (1)
{In formula (1), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and ^XI and X ^II are independently − (COO) _n. (Here, n is 0 or 1.). }
LiX ^I- OR ¹ O-X ^II R ² (2)
{In the formula (2), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and R ² is hydrogen, an alkyl group having 1 to 10 carbon atoms, and carbon. A mono or polyhydroxyalkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a mono or polyhydroxyalkenyl group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group. And X ^I and X ^II are independently − (COO) _n (where n is 0 or 1). }
R ² X ^I- OR ¹ O-X ^II R ³ (3)
{In the formula (3), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and R ² and R ³ are independently hydrogen and 1 carbon atom, respectively. Alkyl groups of 10 to 10, mono or polyhydroxyalkyl groups with 1 to 10 carbon atoms, alkenyl groups with 2 to 10 carbon atoms, mono or polyhydroxyalkenyl groups with 2 to 10 carbon atoms, cycloalkyl groups with 3 to 6 carbon atoms , Or an aryl group, and ^XI and X ^II are independently − (COO) _n (where n is 0 or 1). }
Of a compound selected from among the content per unit mass of the positive electrode material layer upon the C, the C is ^{1.60 × 10 -4 mol / g~150.0 ×} 10 -4 mol / g A non-aqueous lithium-type power storage element.
[2]
The formula CH ₃ OX ¹ {in the formula, X ¹ is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. }, The content of the compound represented by the negative electrode material layer per unit mass is defined as D, and the formula C ₂ H ₅ OX ² {in the formula, X ² is − (O) _n Li or − (COO). ) _N Li, and n is 0 or 1. } When the content of the compound represented by} per unit mass of the negative electrode material layer is E, 1.10 ≦ D / E ≦ 15.00. element.
[3]
The positive electrode is one or more lithium compounds selected from lithium carbonate, lithium oxide, lithium hydroxide, lithium fluoride, lithium chloride, lithium oxalate, lithium iodide, lithium nitride, lithium oxalate, and lithium acetate. When the average particle size of the lithium compound is X ₁ , it is 0.1 μm ≤ X ₁ ≤ 10 μm, and when the average particle size of the positive electrode active material is Y ₁ , it is 2 μm ≤ Y ₁ ≤ 20 μm. , X ₁ <Y ₁ , and the amount of the lithium compound contained in the positive electrode is 1% by mass or more and 50% by mass or less, according to [1] or [2]. ..
[4]
The non-aqueous electrolyte solution contains dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC), and the volume ratio (DMC / EMC) of the dimethyl carbonate to the ethyl methyl carbonate is 0.5 or more and 8.0 or less. The non-aqueous lithium-type power storage element according to any one of [1] to [3].
[5]
Any one of [1] to [4], wherein the non-aqueous electrolyte solution contains at least one organic solvent selected from the group consisting of ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate and fluoroethylene carbonate. The non-aqueous lithium-type power storage element according to the section.
[6]
The non-aqueous lithium-type power storage element according to any one of [1] to [5], wherein the positive electrode current collector and the negative electrode current collector are non-porous metal foils.
[7]
The non-aqueous lithium-type power storage element according to any one of [1] to [6], wherein the non-aqueous electrolyte solution _{contains LiPF 6} and / or LiBF _4.
[8]
[1] to [7], wherein the concentration of LiN (SO ₂ F) _{2 in} the non-aqueous electrolyte solution is 0.3 mol / L or more and 1.5 mol / L or less based on the total amount of the non-aqueous electrolyte solution. The non-aqueous lithium-type power storage element according to any one of the items.
[9]
The amount of mesopores derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by the BJH method for the positive electrode active material contained in the positive electrode active material layer is V1 (cc / g), and the diameter is less than 20 Å calculated by the MP method. When the amount of micropores derived from the pores is V2 (cc / g), 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0 are satisfied, and the measurement is performed by the BET method. The non-aqueous lithium-type power storage element according to any one of [1] to [8], which is an activated carbon having a specific surface area of 1,500 m ² / g or more and 3,000 m ^{2 / g or less.}
[10]
The positive electrode active material contained in the positive electrode active material layer has a mesopore amount V1 (cc / g) of 0.8 <V1 ≦ 2.5 derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by the BJH method. The micropore amount V2 (cc / g) derived from the pores having a diameter of less than 20 Å calculated by the MP method satisfies 0.8 <V2 ≦ 3.0, and the specific surface area measured by the BET method is 2. The non-aqueous lithium-type power storage element according to any one of [1] to [8], which is an activated carbon exhibiting 300 m ² / g or more and 4,000 m ^{2 / g or less.}
[11]
The non-aqueous system according to any one of [1] to [10], wherein the amount of lithium ions doped in the negative electrode active material contained in the negative electrode is 530 mAh / g or more and 2,500 mAh / g or less per unit mass. Lithium-type power storage element.
[12]
The non-aqueous lithium power storage device according to any one of [1] to [11], wherein the negative electrode active material has a BET specific surface area of 100 m ² / g or more and 1,500 m ^{2 / g or less.}
[13]
The non-aqueous lithium type according to any one of [1] to [10], wherein the amount of lithium ions doped in the negative electrode active material contained in the negative electrode is 50 mAh / g or more and 700 mAh / g or less per unit mass. Power storage element.
[14]
The non-aqueous lithium power storage device according to any one of [1] to [10] and [13], wherein the negative electrode active material has a BET specific surface area of 1 m ² / g or more and 50 m ^{2 / g or less.}
[15]
The non-aqueous lithium-type power storage element according to [13] or [14], wherein the average particle size of the negative electrode active material is 1 μm or more and 10 μm or less.
[16]
The initial internal resistance at a cell voltage of 4 V is Ra (Ω), the capacitance is F (F), the amount of power is E (Wh), and the volume of the exterior body containing the electrode laminate is V (L). And when the internal resistance at an ambient temperature of -10 ° C is Rb, the following requirements (a), (b), and (c) are:
(A) The product Ra / F of Ra and F is 0.3 or more and 3.0 or less.
(B) E / V is 15 or more and 50 or less.
(C) The non-aqueous lithium-type power storage device according to any one of [1] to [15], which simultaneously satisfies Rb / Ra of 10 or less.
[17]
When the initial internal resistance at a cell voltage of 4 V is Ra (Ω) and the internal resistance at 25 ° C after storage at a cell voltage of 4 V and an environmental temperature of 60 ° C. for 2 months is Rc (Ω), the following (d) And (e) requirement:
(D) Rc / Ra is 0.3 or more and 3.0 or less.
(E) The amount of gas generated when stored for 2 months at a cell voltage of 4 V and an environmental temperature of 60 ° C. is 30 × 10 ^-3 cc / F or less at 25 ° C.
The non-aqueous lithium-type power storage element according to any one of [1] to [16], which satisfies the above conditions at the same time.
[18]
In the nail piercing test performed under the conditions of a cell voltage of 4.0 V, a nail diameter of 2.5 mmΦ, and a nail piercing speed of 20 mm / sec, the heat generation temperature ΔT at the time of the test was less than 80 ° C. [1] to [17]. The non-aqueous lithium-type power storage element according to any one of the above.
[19]
A power storage module using the non-aqueous lithium power storage element according to any one of [1] to [18].
[20]
A power regeneration system using the non-aqueous lithium-type power storage element according to any one of [1] to [18] or the power storage module according to [19].
[21]
A power load leveling system using the non-aqueous lithium-type power storage element according to any one of [1] to [18] or the power storage module according to [19].
[22]
An uninterruptible power supply system using the non-aqueous lithium-type power storage element according to any one of [1] to [18] or the power storage module according to [19].
[23]
A non-contact power supply system using the non-aqueous lithium-type power storage element according to any one of [1] to [18] or the power storage module according to [19].
[24]
An energy harvesting system using the non-aqueous lithium-type power storage element according to any one of [1] to [18] or the power storage module according to [19].
[25]
A power storage system using the non-aqueous lithium power storage element according to any one of [1] to [18] or the power storage module according to [19].

According to the present invention, it is possible to provide a lithium ion capacitor that has both high input / output characteristics in a wide temperature range, gas generation due to decomposition of an electrolytic solution at a high temperature, and suppression of characteristic deterioration due to the gas generation.

Hereinafter, embodiments of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the present embodiment. The upper limit value and the lower limit value in each numerical range of the present embodiment can be arbitrarily combined to form an arbitrary numerical range.
Generally, a non-aqueous lithium-type power storage element includes a positive electrode, a negative electrode, a separator, an electrolytic solution, and an exterior body as main components. As the electrolytic solution, an organic solvent in which a lithium salt is dissolved (hereinafter, referred to as a non-aqueous electrolytic solution) is used.

[Positive electrode]
The positive electrode has a positive electrode current collector and a positive electrode active material layer existing on one side or both sides thereof.
Further, the positive electrode preferably contains a lithium compound as a positive electrode precursor before assembling the power storage element. As will be described later, in the present embodiment, it is preferable to pre-dope the negative electrode with lithium ions in the energy storage element assembly process. As the pre-doping method, a voltage is applied between the positive electrode precursor and the negative electrode after assembling the power storage element using the positive electrode precursor containing the lithium compound, the negative electrode, the separator, the exterior body, and the non-aqueous electrolyte solution. Is preferable. The lithium compound is preferably contained in the positive electrode active material layer formed on the positive electrode current collector of the positive electrode precursor.
In the present specification, the positive electrode state before the lithium doping process is defined as a positive electrode precursor, and the positive electrode state after the lithium doping process is defined as a positive electrode.

[Positive electrode active material layer]
The positive electrode active material layer contained in the positive electrode contains a positive electrode active material containing activated carbon. In addition to this, the positive electrode active material layer may contain an optional component such as a conductive filler, a binder, and a dispersion stabilizer, if necessary.
Further, it is preferable that the positive electrode active material layer of the positive electrode precursor contains a lithium compound other than the positive electrode active material.

[Positive electrode active material]
The positive electrode active material contains activated carbon. As the positive electrode active material, only activated carbon may be used, or in addition to activated carbon, other carbon materials as described later may be used in combination. As the carbon material, it is more preferable to use carbon nanotubes, a conductive polymer, or a porous carbon material. The positive electrode active material may be used by mixing one or more kinds of carbon materials including activated carbon, or may contain a material other than the carbon material (for example, a composite oxide of lithium and a transition metal).
Preferably, the content of the carbon material with respect to the total amount of the positive electrode active material is 50% by mass or more, more preferably 70% by mass or more. The content of the carbon material can be 100% by mass, but is preferably 90% by mass or less or 80% by mass or less, for example, from the viewpoint of obtaining a good effect by the combined use of other materials.

There are no particular restrictions on the type of activated carbon used as the positive electrode active material and its raw material. However, it is preferable to optimally control the pores of the activated carbon in order to achieve both high input / output characteristics and high energy density. Specifically, the amount of mesopores derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by the BJH method is V1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 Å calculated by the MP method. When setting to V2 (cc / g)
(1) For high input / output characteristics, 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0 are satisfied, and the specific surface area measured by the BET method is 1,500 m ^2. Activated carbon having a / g or more and 3,000 m ² / g or less (hereinafter, also referred to as activated carbon 1) is preferable, and also.
(2) In order to obtain a high energy density, 0.8 <V1 ≦ 2.5 and 0.8 <V2 ≦ 3.0 are satisfied, and the specific surface area measured by the BET method is 2,300 m ^2. Activated carbon having a / g or more and 4,000 m ² / g or less (hereinafter, also referred to as activated carbon 2) is preferable.

Hereinafter, the (1) activated carbon 1 and the (2) activated carbon 2 will be described individually in sequence.

[Activated carbon 1]
The mesopore amount V1 of the activated carbon 1 is preferably a value larger than 0.3 cc / g from the viewpoint of increasing the input / output characteristics when incorporated in the power storage element. On the other hand, from the viewpoint of suppressing a decrease in the bulk density of the positive electrode, it is preferably 0.8 cc / g or less. The above V1 is more preferably 0.35 cc / g or more and 0.7 cc / g or less, and further preferably 0.4 cc / g or more and 0.6 cc / g or less.
The micropore amount V2 of the activated carbon 1 is preferably 0.5 cc / g or more in order to increase the specific surface area and the capacity of the activated carbon. On the other hand, from the viewpoint of suppressing the bulk of the activated carbon, increasing the density as an electrode, and increasing the capacity per unit volume, it is preferably 1.0 cc / g or less. The above V2 is more preferably 0.6 cc / g or more and 1.0 cc / g or less, and further preferably 0.8 cc / g or more and 1.0 cc / g or less. The combination of the lower limit and the upper limit can be arbitrary.

The ratio of the mesopore amount V1 to the micropore amount V2 (V1 / V2) is preferably in the range of 0.3 ≦ V1 / V2 ≦ 0.9. That is, V1 / V2 is preferably 0.3 or more from the viewpoint of increasing the ratio of the mesopore amount to the micropore amount to the extent that the decrease in output characteristics can be suppressed while maintaining a high capacity. On the other hand, V1 / V2 is preferably 0.9 or less from the viewpoint of increasing the ratio of the micropore amount to the mesopore amount to the extent that the decrease in capacitance can be suppressed while maintaining the high output characteristics. .. A more preferable range of V1 / V2 is 0.4 ≦ V1 / V2 ≦ 0.7, and a more preferable range of V1 / V2 is 0.55 ≦ V1 / V2 ≦ 0.7. The combination of the lower limit and the upper limit can be arbitrary.

The average pore diameter of the activated carbon 1 is preferably 17 Å or more, more preferably 18 Å or more, and most preferably 20 Å or more from the viewpoint of maximizing the output of the obtained power storage element. Further, from the viewpoint of maximizing the capacity, the average pore diameter of the activated carbon 1 is preferably 25 Å or less.

BET specific surface area of the activated carbon 1 is preferably from 1,500 m ² / g or more 3,000 m ² / g, more preferably not more than 1,500 m ² / g or more 2,500 m ² / g. When the BET specific surface area is 1,500 m ² / g or more, a good energy density can be easily obtained, while when the BET specific surface area is 3,000 m ² / g or less, in order to maintain the strength of the electrode. Since it is not necessary to add a large amount of binder, the performance per electrode volume is improved. The combination of the lower limit and the upper limit can be arbitrary.

Activated carbon 1 having the above characteristics can be obtained, for example, by using the raw materials and the treatment method described below.
In the present embodiment, the carbon source used as the raw material of the activated carbon 1 is not particularly limited. For example, plant-based raw materials such as wood, wood flour, coconut shells, by-products during pulp production, bagas, waste sugar honey; peat, sub-charcoal, brown charcoal, bituminous charcoal, smokeless charcoal, petroleum distillation residue components, petroleum pitch, coke, coal tar, etc. Fossil raw materials; various synthetic resins such as phenol resin, vinyl chloride resin, vinyl acetate resin, melamine resin, urea resin, resorcinol resin, celluloid, epoxy resin, polyurethane resin, polyester resin, polyamide resin; polybutylene, polybutadiene, polychloroprene, etc. Synthetic rubber; other synthetic wood, synthetic pulp, etc., and carbonized products thereof. Among these raw materials, plant-based raw materials such as coconut shells and wood flour and their carbides are preferable, and coconut shell carbides are particularly preferable, from the viewpoint of mass production and cost.

As the carbonization and activation methods for converting these raw materials into the activated carbon 1, for example, known methods such as a fixed bed method, a moving bed method, a fluidized bed method, a slurry method, and a rotary kiln method can be adopted.
Examples of the carbonization method for these raw materials include an inert gas such as nitrogen, carbon dioxide, helium, argon, xenone, neon, carbon monoxide, and combustion exhaust gas, or another gas containing these inert gases as main components. Examples thereof include a method of firing at about 400 to 700 ° C. (preferably 450 to 600 ° C.) for about 30 minutes to 10 hours using a mixed gas.

As a method for activating the carbide obtained by the above carbonization method, a gas activation method in which the carbide is fired using an activation gas such as steam, carbon dioxide, or oxygen is preferably used. Of these, a method using water vapor or carbon dioxide as the activating gas is preferable.
In this activation method, the above-mentioned carbide is supplied for 3 to 12 hours (preferably 5 to 11) while supplying the activation gas at a ratio of 0.5 to 3.0 kg / h (preferably 0.7 to 2.0 kg / h). It is preferable to activate by raising the temperature to 800 to 1,000 ° C. over time, more preferably 6 to 10 hours).
Further, the carbide may be first activated in advance prior to the activation treatment of the carbide. In this primary activation, a method in which a carbon material is usually fired at a temperature of less than 900 ° C. using an activation gas such as steam, carbon dioxide, or oxygen to activate the gas can be preferably adopted.
By appropriately combining the firing temperature and firing time in the carbonization method with the amount of activated gas supplied, the rate of temperature rise, and the maximum activation temperature in the activation method, activated carbon 1 having the above characteristics that can be used in the present embodiment is produced. can do.

The average particle size of activated carbon 1 is preferably 2 to 20 μm.
When the average particle size is 2 μm or more, the capacity per electrode volume tends to be high because the density of the active material layer is high. Here, if the average particle size is small, the durability may be low, but if the average particle size is 2 μm or more, such a defect is unlikely to occur. On the other hand, when the average particle size is 20 μm or less, it tends to be easily adapted to high-speed charging / discharging. The average particle size is more preferably 2 to 15 μm, still more preferably 3 to 10 μm. The upper and lower limits of the average particle size range can be arbitrarily combined.

[Activated carbon 2]
The mesopore amount V1 of the activated carbon 2 is preferably a value larger than 0.8 cc / g from the viewpoint of increasing the output characteristics when incorporated in the power storage element. On the other hand, V1 is preferably 2.5 cc / g or less from the viewpoint of suppressing a decrease in the capacity of the power storage element. The above V1 is more preferably 1.00 cc / g or more and 2.0 cc / g or less, and further preferably 1.2 cc / g or more and 1.8 cc / g or less.

On the other hand, the micropore amount V2 of the activated carbon 2 is preferably a value larger than 0.8 cc / g in order to increase the specific surface area and the capacity of the activated carbon. On the other hand, V2 is preferably 3.0 cc / g or less from the viewpoint of increasing the density of activated carbon as an electrode and increasing the capacity per unit volume. V2 is more preferably more than 1.0 cc / g and 2.5 cc / g or less, and further preferably 1.5 cc / g or more and 2.5 cc / g or less.

The activated carbon 2 having the above-mentioned meso-pore amount and micro-pore amount has a higher BET specific surface area than the activated carbon used for conventional electric double layer capacitors or lithium ion capacitors. The specific value of the BET specific surface area of the activated carbon 2 ^{is preferably 2,300 m 2} / g or more and 4,000 m ² / g or less. The lower limit of the BET specific surface area ^{is more preferably 3,000 m 2} / g or more, and further preferably 3,200 m ² / g or more. On the other hand, the upper limit of the BET specific surface area ^{is more preferably 3,800 m 2} / g or less. When the BET specific surface area is 2,300 m ² / g or more, a good energy density can be easily obtained, while when the BET specific surface area is 4,000 m ² / g or less, in order to maintain the strength of the electrode. Since it is not necessary to add a large amount of binder, the performance per electrode volume is improved.
Regarding the V1, V2 and BET specific surface areas of the activated carbon 2, the upper and lower limits of the preferable ranges described above can be arbitrarily combined.

Activated carbon 2 having the above characteristics can be obtained by using, for example, the raw materials and treatment methods described below.
The carbon source used as a raw material for the activated charcoal 2 is not particularly limited as long as it is a carbon source normally used as a raw material for activated charcoal. And other fossil-based raw materials; various synthetic resins such as phenol resin, furan resin, vinyl chloride resin, vinyl acetate resin, melamine resin, urea resin, resorcinol resin and the like can be mentioned. Among these raw materials, phenol resin and furan resin are particularly preferable because they are suitable for producing activated carbon having a high specific surface area.

Examples of the method of carbonizing these raw materials or the heating method at the time of activation treatment include known methods such as a fixed bed method, a moving bed method, a fluidized bed method, a slurry method, and a rotary kiln method. As the heating atmosphere, an inert gas such as nitrogen, carbon dioxide, helium, or argon, or a gas containing these inert gases as the main component and mixed with other gases is used. The carbonization temperature is preferably about 400 to 700 ° C. (the lower limit is preferably 450 ° C. or higher, more preferably 500 ° C. or higher, and the upper limit is preferably 650 ° C. or lower) for about 0.5 to 10 hours. ..

Examples of the method for activating the carbide after the carbide treatment include a gas activation method in which the carbide is fired using an activated gas such as water vapor, carbon dioxide, and oxygen, and an alkali metal activation method in which heat treatment is performed after mixing with an alkali metal compound. The alkali metal activation method is preferable for producing activated carbon having a high specific surface area.
In this activation method, the mixture was mixed so that the mass ratio of the carbide to the alkali metal compound such as KOH or NaOH was 1: 1 or more (the amount of the alkali metal compound was the same as or larger than the amount of the carbide). Later, the mixture was heated in an inert gas atmosphere at 600 to 900 ° C. (preferably 650 ° C. to 850 ° C.) for 0.5 to 5 hours, and then the alkali metal compound was washed and removed with acid and water. , Further drying.

It was mentioned earlier that the mass ratio of the carbide to the alkali metal compound (= carbide: alkali metal compound) is preferably 1: 1 or more. However, as the amount of the alkali metal compound increases, the amount of mesopores increases, but the mass ratio is 1: 1. Since the amount of pores tends to increase sharply around 3.5, the mass ratio is preferably such that the amount of the alkali metal compound increases rather than 1: 3, and it is preferably 1: 5.5 or less. The mass ratio increases as the amount of the alkali metal compound increases, but is preferably in the above range in consideration of treatment efficiency such as subsequent cleaning.
In order to increase the amount of micropores and not to increase the amount of mesopores, it is advisable to increase the amount of carbides at the time of activation and mix with KOH. In order to increase both the amount of micropores and the amount of mesopores, it is advisable to use a large amount of KOH. Further, in order to mainly increase the amount of mesopores, it is preferable to perform steam activation after performing alkali activation treatment.
The average particle size of the activated carbon 2 is preferably 2 μm or more and 20 μm or less, and more preferably 3 μm or more and 10 μm or less.

[Usage of activated carbon]
Activated carbons 1 and 2 may be one type of activated carbon, or may be a mixture of two or more types of activated carbon, and each of the above-mentioned characteristic values may be shown as a whole mixture.
As the activated carbons 1 and 2 described above, either one of them may be selected and used, or both may be mixed and used.
The positive electrode active material is a material other than activated carbon 1 and 2 (for example, activated carbon that does not have the specific V1 and / or V2, or a material other than activated carbon (for example, a composite oxide of lithium and a transition metal)). It may be included. In the exemplary embodiment, the content of the activated carbon 1, the content of the activated carbon 2, or the total content of the activated carbons 1 and 2 is preferably more than 50% by mass, respectively, and 70% by mass or more of the total positive electrode active material. More preferably, 90% by mass or more is further preferable, and 100% by mass is most preferable.

The content ratio of the positive electrode active material in the positive electrode active material layer is preferably 35% by mass or more and 95% by mass or less based on the total mass of the positive electrode active material layer in the positive electrode precursor. The upper limit of the content ratio of the positive electrode active material is more preferably 45% by mass or more, further preferably 55% by mass or more. On the other hand, the lower limit of the content ratio of the positive electrode active material is more preferably 90% by mass or less, and further preferably 80% by mass or less. By setting the content ratio in this range, suitable charge / discharge characteristics are exhibited.

[Lithium compound]
The positive electrode active material layer of the positive electrode precursor of the present embodiment preferably contains a lithium compound other than the positive electrode active material. Further, the positive electrode active material layer of the positive electrode of the present embodiment contains a lithium compound other than the positive electrode active material.
From the viewpoint that the lithium compound can be decomposed at the positive electrode in the lithium doping step described later and release lithium ions, lithium carbonate, lithium oxide, lithium hydroxide, lithium fluoride, lithium chloride, and sucrose are formed. One or more selected from the group consisting of lithium, lithium iodide, lithium nitride, lithium oxalate, and lithium acetate are preferably used. Among them, lithium carbonate, lithium oxide, and lithium hydroxide are more preferable, and lithium carbonate is further preferable from the viewpoint that it can be handled in the air and has low hygroscopicity. Such a lithium compound decomposes when a voltage is applied, functions as a dopant source for lithium doping to the negative electrode, and forms pores in the positive electrode active material layer. Therefore, the electrolyte solution is excellent in retention and ionic conductivity. It is possible to form an excellent positive electrode.

[Lithium compound of positive electrode precursor]
The lithium compound is preferably in the form of particles. The average particle size of the lithium compound contained in the positive electrode precursor is preferably 0.1 μm or more and 100 μm or less. The upper limit of the average particle size of the lithium compound contained in the positive electrode precursor is more preferably 50 μm or less, further preferably 20 μm or less, and most preferably 10 μm or less. On the other hand, the lower limit of the average particle size of the lithium compound contained in the positive electrode precursor is more preferably more than 0.1 μm, further preferably 0.5 μm or more. When the average particle size of the lithium compound is 0.1 μm or more, the pores remaining after the oxidation reaction of the lithium compound in the positive electrode have a sufficient volume to hold the electrolytic solution, so that the high load charge / discharge characteristics are exhibited. improves. When the average particle size of the lithium compound is 100 μm or less, the surface area of the lithium compound does not become excessively small, so that the rate of oxidation reaction of the lithium compound can be ensured. The upper and lower limits of the range of the average particle size of the lithium compound can be arbitrarily combined.
Various methods can be used for atomizing the lithium compound. For example, a crusher such as a ball mill, a bead mill, a ring mill, a jet mill, or a rod mill can be used.

The content ratio of the lithium compound in the positive electrode active material layer of the positive electrode precursor is preferably 5% by mass or more and 60% by mass or less based on the total mass of the positive electrode active material layer in the positive electrode precursor, and is preferably 10% by mass or more and 50% by mass or more. It is more preferably mass% or less. By setting the content ratio in this range, it is possible to exert a suitable function as a dopant source for the negative electrode, impart an appropriate degree of porosity to the positive electrode, and combine them with high load charge / discharge efficiency. It is possible to provide an excellent power storage element. The upper and lower limits of this content ratio range can be arbitrarily combined.

[Lithium compound of positive electrode]
The positive electrode preferably contains a lithium compound other than the positive electrode active material. When the average particle size of the lithium compound other than the positive electrode active material contained in the positive electrode is X ₁ , it is preferably 0.1 μm ≤ X ₁ ≤ 10 μm, and more preferably 0.5 μm ≤ X ₁ ≤ 5 μm. be. When X ₁ is 0.1 μm or more, the high load charge / discharge cycle characteristics are improved by adsorbing the fluorine ions generated in the high load charge / discharge cycle. When X ₁ is 10 μm or less, the reaction area with the fluorine ions generated in the high load charge / discharge cycle increases, so that the adsorption of fluorine ions can be performed efficiently.

The lithium compound contained in the positive electrode other than the positive electrode active material is preferably 1% by mass or more and 50% by mass or less, preferably 2.5% by mass or more and 25% by mass, based on the total mass of the positive electrode active material layer in the positive electrode. The following is more preferable. When the amount of the lithium compound is 1% by mass or more, lithium carbonate suppresses the decomposition reaction of the electrolytic solution solvent on the positive electrode in a high temperature environment, so that the high temperature durability is improved, and it is 2.5% by mass or more. , The effect becomes remarkable. Further, when the amount of the lithium compound is 50% by mass or less, the electron conductivity between the positive electrode active materials is relatively small to be inhibited by the lithium compound, so that high input / output characteristics are exhibited, and the amount is 25% by mass or less. , High input / output characteristics become remarkable. The combination of the lower limit and the upper limit can be arbitrary.

<Method of identifying lithium compounds in electrodes>
The method for identifying the lithium compound contained in the positive electrode is not particularly limited, but the lithium compound can be identified by, for example, the following method. For the identification of the lithium compound, it is preferable to identify the lithium compound by combining a plurality of analysis methods described below.
When measuring SEM-EDX, Raman, and XPS described below, the non-aqueous lithium storage element may be disassembled in an argon box, the positive electrode may be taken out, and the electrolyte adhering to the positive electrode surface may be washed before the measurement. preferable. As for the method for cleaning the positive electrode, since the electrolyte adhering to the surface of the positive electrode may be washed away, a carbonate solvent such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate can be preferably used. As a cleaning method, for example, the positive electrode is immersed in a diethyl carbonate solvent 50 to 100 times the weight of the positive electrode for 10 minutes or more, and then the solvent is replaced and the positive electrode is immersed again. The positive electrode is then removed from diethyl carbonate, vacuum dried, and then analyzed by SEM-EDX, Raman spectroscopy, and XPS. The vacuum drying conditions are such that the residual diethyl carbonate in the positive electrode is 1% by mass or less in the range of temperature: 0 to 200 ° C., pressure: 0 to 20 kPa, and time: 1 to 40 hours. The residual amount of diethyl carbonate can be quantified based on a calibration curve prepared in advance by measuring the GC / MS of the water after washing with distilled water and adjusting the liquid amount, which will be described later.
In ion chromatography described later, anions can be identified by analyzing the water after washing the positive electrode with distilled water.
If the lithium compound cannot be identified by the analysis method, other analysis methods include ⁷ Li-solid NMR, XRD (X-ray diffraction), TOF-SIMS (time-of-flight secondary ion mass spectrometry), and AES (Auger electron spectroscopy). Lithium compounds can also be identified by using spectroscopy), TPD / MS (heat-of-flight mass spectrometry), DSC (differential scanning calorimetry), and the like.

[Scanning electron microscope-energy dispersive X-ray analysis (SEM-EDX)]
The lithium compound and the positive electrode active material can be identified by oxygen mapping using an SEM-EDX image of the positive electrode surface measured at an observation magnification of 1000 to 4000 times. As a measurement example of the SEM-EDX image, the acceleration voltage is 10 kV, the emission current is 1 μA, the number of measurement pixels is 256 × 256 pixels, and the number of integrations is 50. In order to prevent the sample from being charged, gold, platinum, osmium or the like can be surface-treated by a method such as vacuum deposition or sputtering. Regarding the method for measuring the SEM-EDX image, it is preferable to adjust the brightness and contrast so that the brightness does not reach the maximum brightness and the average value of the brightness is in the range of 40% to 60%. When the obtained oxygen mapping is binarized based on the average value of brightness, the particles containing 50% or more of the bright part in area are defined as lithium compounds.

[Microscopic Raman spectroscopy]
The lithium carbonate and the positive electrode active material can be discriminated by Raman imaging of carbonate ions on the surface of the positive electrode precursor measured at an observation magnification of 1000 to 4000 times. As an example of measurement conditions, the excitation light is 532 nm, the excitation light intensity is 1%, the long operation of the objective lens is 50 times, the diffraction grating is 1800 gr / mm, the mapping method is point scanning (slit 65 mm, binning 5 pix), 1 mm step, The exposure time per point can be measured for 3 seconds, the number of integrations can be measured once, and the measurement can be performed under the condition of having a noise filter. For the measured Raman spectrum ^{, a straight baseline is set in the range of 1071-1104 cm -1} , the area is calculated with a positive value from the baseline as the peak of carbonate ions, and the frequency is integrated. At this time, the noise component is added. The frequency for the carbonate ion peak area approximated by the Gaussian function is subtracted from the carbonate ion frequency distribution.

[X-ray Photoelectron Spectroscopy (XPS)]
The bonding state of the lithium compound can be determined by analyzing the electronic state by XPS. As an example of measurement conditions, the X-ray source is monochromatic AlKα, the X-ray beam diameter is 100 μmφ (25 W, 15 kV), the path energy is narrow scan: 58.70 eV, there is charge neutralization, and the number of sweeps is narrow scan: 10 times. (Carbon, oxygen) 20 times (fluorine) 30 times (phosphorus) 40 times (lithium element) 50 times (silicon), energy step can be measured under the condition of narrow scan: 0.25 eV. It is preferable to clean the surface of the positive electrode by sputtering before measuring XPS. As the sputtering conditions, for example, the surface of the positive electrode can be cleaned under the condition of an acceleration voltage of 1.0 kV, 2 mm × 2 mm for 1 minute ( _{1.25 nm / min in terms of SiO 2).}
About the obtained XPS spectrum
The peaks of the binding energy of Li1s of 50 to 54 eV are LiO ₂ or Li-C bonds, and the peaks of Li1s are LiF, Li ₂ CO ₃ , and Li _x PO _y F _z (in the formula, x, y, and z are respectively. It is an integer of 1 to 6);
C1s binding energy 285 eV peak is CC bond, 286 eV peak is CO bond, 288 eV peak is COO, 290-292 eV peak is CO ₃ ^2- , CF bond;
The peaks of the binding energy of O1s of 527 to 530 eV are O ^2- (Li ₂ O), and the peaks of 513 to 532 eV are CO, CO ₃ , OH, PO _x (x is an integer of 1 to 4 in the formula), SiO. _x (in the formula, x is an integer of 1 to 4), the peak of 533 eV is CO, SiO _x (in the formula, x is an integer of 1 to 4);
The peak of binding energy 685eV of F1s LiF, C-F bonds and a peak of 687 _eV, (wherein, x, y, and z are an integer from 1 to 6 _{respectively) Li x PO y F z,} PF 6 - ;
Regarding the binding energy of P2p, the peak of 133 eV is PO _x (in the formula, x is an integer of 1 to 4), and the peak of 134 to 136 eV is PF _x (in the formula, x is an integer of 1 to 6);
The peak of binding energy 99eV of Si2p Si, silicide, peak _Si x _{O y} of 101～107EV (wherein, x and y are arbitrary integers)
Can be attributed as.
When the peaks of the obtained spectrum overlap, it is preferable to separate the peaks assuming a Gaussian function or a Lorentz function and assign the spectra. The existing lithium compound can be identified from the obtained measurement result of the electronic state and the result of the presence element ratio.

[Ion chromatography]
The carbonate ion eluted in water can be identified by washing the positive electrode precursor with distilled water and analyzing the washed water by ion chromatography. As the column to be used, an ion exchange type, an ion exclusion type, and a reverse phase ion pair type can be used. As the detector, an electrical conductivity detector, an ultraviolet-visible absorptiometric detector, an electrochemical detector, etc. can be used, and a suppressor method in which a suppressor is installed in front of the detector, or electricity without a suppressor. A non-suppressor method using a solution having low conductivity as an eluent can be used. It can also be measured in combination with a mass spectrometer and a charged particle detector.
The retention time of the sample is constant for each ionic species component if conditions such as the column to be used and the eluent to be used are determined, and the magnitude of the peak response differs for each ionic species, but it depends on the concentration of the ionic species. Proportional. By measuring in advance a standard solution having a known concentration that ensures traceability, it is possible to qualitatively and quantify the ionic species component.

If the lithium compound cannot be identified by the above method, other analysis methods include solid ⁷ Li-NMR, XRD (X-ray diffraction), TOF-SIMS (time-of-flight secondary ion mass spectrometry), and AES (Auger electron spectroscopy). ), TPD / MS (mass spectrometry of heat generated gas), DSC (differential scanning calorimetry) and the like, the lithium compound can also be identified.

(Average particle size of lithium compound)
The positive electrode contains a lithium compound other than the positive electrode active material. When the average particle size of the lithium compound other than the positive electrode active material contained in the positive electrode is X ₁ , 0.1 μm ≤ X ₁ ≤ 10 μm, and when the average particle size of the positive electrode active material is Y ₁ , 2 μm ≤ It is preferable that Y ₁ ≤ 20 μm and X ₁ <Y _1. X ₁ is more preferably 0.5 μm ≦ X ₁ ≦ 5 μm. When X ₁ is 0.1 μm or more, the high load charge / discharge cycle characteristics are improved by adsorbing the fluorine ions generated in the high load charge / discharge cycle. When X ₁ is 10 μm or less, the reaction area with the fluorine ions generated in the high load charge / discharge cycle increases, so that the adsorption of fluorine ions can be performed efficiently. When Y ₁ is 2 μm or more, electron conductivity between the positive electrode active materials can be ensured. When Y ₁ is 20 μm or less, high output characteristics can be exhibited because the reaction area with the electrolyte ion increases. When X ₁ <Y ₁ , the gaps formed between the positive electrode active materials are filled with lithium carbonate, so that the energy density can be increased while ensuring the electron conductivity between the positive electrode active materials.

The measuring method of X ₁ and Y ₁ is not particularly limited, but it can be calculated from the SEM image of the positive electrode cross section and the SEM-EDX image shown below. As a method for forming the positive electrode cross section, a broad ion beam (BIB) process can be used in which an Ar beam is irradiated from the upper part of the positive electrode to form a smooth cross section along the edge of the shielding plate installed directly above the sample. .. When lithium carbonate is contained in the positive electrode, the distribution of carbonate ions can be obtained by measuring Raman imaging of the cross section of the positive electrode.

[Calculation method of _{X 1} and Y _1]
X ₁ and Y ₁ can be obtained by image analysis of images obtained from the positive electrode cross section SEM-EDX measured in the same field of view as the positive electrode cross section SEM. The particles X of the lithium compound identified in the SEM image of the cross section of the positive electrode and the other particles are defined as the particles Y of the positive electrode active material, and the cross-sectional area of each of the X and Y particles observed in the SEM image of the cross section is S is obtained, and the particle diameter d calculated by the following formula (1) is obtained.

｛式中、円周率をπとする。｝

{In the formula, let the pi be π. }

Using the obtained particle size d, the volume average particle size X ₀ and Y ₀ are obtained in the following mathematical formula (2).

Measure at 5 or more points by changing the field of view of the positive electrode cross section, and take _{the average value of X 0 and Y 0} , respectively, as the average particle size X ₁ and Y ₁ .

The lithium compound contained in the positive electrode gradually decomposes and gasifies when exposed to a high potential of about 4.0 V or higher, and the generated gas resists the diffusion of ions in the electrolytic solution. It will cause a rise. Therefore, it is preferable to form a film composed of a fluorine-containing compound on the surface of the lithium compound to suppress the reaction of the lithium compound.

[Method for quantifying lithium compounds]
The method for quantifying the lithium compound contained in the positive electrode is described below.
The positive electrode can be washed with an organic solvent, then with distilled water, and the lithium compound can be quantified from the change in positive mass before and after washing with distilled water. Although area measurement is positive is not particularly limited, it is preferably, more preferably 25 cm ² or more 150 cm ² or less from the viewpoint of reducing the variation in measurement is 5 cm ² or more 200 cm ² or less. If the area is 5 cm ² or more, the reproducibility of measurement is ensured. If the area is 200 cm ² or less, the handling of the sample is excellent. The organic solvent for cleaning the positive electrode is not particularly limited as long as it can remove the non-aqueous electrolyte decomposition product deposited on the surface of the positive electrode, but the lithium compound can be obtained by using an organic solvent having a solubility of the lithium compound of 2% or less. It is preferable because the elution of the solvent is suppressed. As the organic solvent for cleaning the positive electrode, for example, a polar solvent such as methanol or acetone is preferably used.

As a method for cleaning the positive electrode, for example, the positive electrode is sufficiently immersed in a methanol solution 50 to 100 times the mass of the positive electrode for 3 days or more. At this time, it is preferable to take measures such as covering the container so that methanol does not volatilize. After that, the positive electrode is taken out from methanol, vacuum dried, and the mass of the positive electrode after vacuum drying is M ₀ [g]. The conditions for vacuum drying are, for example, a condition in which the residual amount of methanol in the positive electrode is 1% by mass or less in the range of temperature: 100 to 200 ° C., pressure: 0 to 10 kPa, and time: 5 to 20 hours. The residual amount of methanol can be quantified based on the calibration curve prepared in advance by measuring the GC / MS of the water after washing with distilled water, which will be described later. After vacuum drying, the positive electrode is sufficiently immersed in distilled water having 100 times the mass of the positive electrode (100M ₀ [g]) for 3 days or more. At this time, it is preferable to take measures such as covering the container so that the distilled water does not volatilize. When measuring ion chromatography, the amount of liquid is adjusted so that _{the amount of distilled water is 100M 0 [g].} After immersing in distilled water for 3 days or more, the positive electrode is taken out from the distilled water and vacuum dried in the same manner as the above methanol washing. The mass of the positive electrode at this time is set to M ₁ [g], and subsequently, in order to measure the mass of the collected positive electrode of the obtained positive electrode, a positive electrode active material layer on the current collector is used using a spatula, a brush, a brush, or the like. Get rid of. Assuming that the mass of the obtained positive electrode current collector is M ₂ [g], the mass% Z of the lithium compound contained in the positive electrode is calculated by the following mathematical formula (3):
Z = 100 × [1- (M _1- M ₂ ) / (M _0- M ₂ )]. .. .. Formula (3)
Can be calculated by

[Method of distinguishing between lithium compound and positive electrode active material]
The oxygen-containing lithium compound and the positive electrode active material can be identified by oxygen mapping using an SEM-EDX image of the positive electrode surface measured at an observation magnification of 1000 to 4000 times. As a measurement example of the SEM-EDX image, the acceleration voltage is 10 kV, the emission current is 1 μA, the number of measurement pixels is 256 × 256 pixels, and the number of integrations is 50. In order to prevent the sample from being charged, the surface can be treated with gold, platinum, osmium or the like by a method such as vacuum deposition or sputtering. As the measurement conditions of the SEM-EDX image, it is preferable to adjust the brightness and the contrast so that the brightness does not reach the maximum brightness and the average value of the brightness is in the range of 40% to 60%. Particles containing 50% or more of bright areas binarized with respect to the obtained oxygen mapping based on the average value of brightness are designated as lithium compounds.

[Arbitrary component of positive electrode active material layer]
The positive electrode active material layer in the present embodiment may contain an optional component such as a conductive filler, a binder, and a dispersion stabilizer in addition to the positive electrode active material and the lithium compound, if necessary.
The conductive filler is not particularly limited, and for example, acetylene black, ketjen black, vapor-grown carbon fibers, graphite, carbon nanotubes, a mixture thereof, and the like can be used. The amount of the conductive filler used is preferably 0 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the positive electrode active material. It is more preferably 0.01 parts by mass or more and 20 parts by mass or less, and further preferably 1 part by mass or more and 15 parts by mass or less. If the amount of the conductive filler used is more than 30 parts by mass, the content ratio of the positive electrode active material in the positive electrode active material layer is small, and the energy density per volume of the positive electrode active material layer is lowered, which is not preferable.

The binder is not particularly limited, but for example, PVdF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), polyimide, latex, styrene-butadiene copolymer, fluororubber, acrylic copolymer and the like. Can be used. The amount of the binder used is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 3 parts by mass or more and 27 parts by mass or less, and further preferably 5 parts by mass or more and 25 parts by mass with respect to 100 parts by mass of the positive electrode active material. It is less than a part. When the amount of the binder used is 1 part by mass or more, sufficient electrode strength is exhibited. On the other hand, when the amount of the binder used is 30 parts by mass or less, high input / output characteristics are exhibited without inhibiting the ingress and egress and diffusion of ions into the positive electrode active material.

The dispersion stabilizer is not particularly limited, but for example, PVP (polyvinylpyrrolidone), PVA (polyvinyl alcohol), a cellulose derivative and the like can be used. The amount of the dispersion stabilizer used is preferably more than 0 parts by mass or 0.1 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the positive electrode active material. When the amount of the dispersion stabilizer used is 10 parts by mass or less, high input / output characteristics are exhibited without inhibiting the ingress and egress and diffusion of ions into the positive electrode active material.

[Positive current collector]
The material constituting the positive electrode current collector in the present embodiment is not particularly limited as long as it has high electron conductivity and does not deteriorate due to elution into the electrolytic solution and reaction with the electrolyte or ions, but is not particularly limited. Foil is preferred. Aluminum foil is particularly preferable as the positive electrode current collector in the non-aqueous lithium-type power storage element of the present embodiment.
The metal foil may be a normal metal foil having no irregularities or through holes, a metal foil having irregularities subjected to embossing, chemical etching, electrolytic precipitation, blasting, etc., expanded metal, punching metal, etc. , A metal foil having through holes such as an etching foil may be used.
From the viewpoint of ease of electrode production and high electron conductivity, the positive electrode current collector in the present embodiment is preferably non-porous. In the specification of the present application, the non-porous positive electrode current collector means that lithium ions pass through the positive electrode current collector and the lithium ions are homogenized on the front and back surfaces of the positive electrode, at least in the coated region of the positive electrode active material layer. It means a positive electrode current collector that does not have a degree of holes. Therefore, within the range in which the effect of the present invention is exhibited, the positive electrode current collector having extremely small diameter or a small amount of holes and the positive electrode current collector having holes in the uncoated region of the positive electrode active material layer are also excluded. is not it. Further, in the present embodiment, at least the region where the positive electrode active material layer is coated is non-porous in the positive electrode current collector, and the surplus portion of the positive electrode current collector where the positive electrode active material layer is not coated is covered. May or may not have holes.
The thickness of the positive electrode current collector is not particularly limited as long as the shape and strength of the positive electrode can be sufficiently maintained, but is preferably 1 to 100 μm, for example.

[Manufacturing of positive electrode precursor]
In the present embodiment, the positive electrode precursor serving as the positive electrode of the non-aqueous lithium-type power storage element can be manufactured by a technique for manufacturing electrodes in known lithium ion batteries, electric double layer capacitors, and the like. For example, a positive electrode active material, a lithium compound, and other optional components used as necessary are dispersed or dissolved in water or an organic solvent to prepare a slurry coating liquid, and this coating liquid is collected as a positive electrode. A positive electrode precursor can be obtained by applying a coating film on one side or both sides of an electric body to form a coating film and drying the coating film. Further, the obtained positive electrode precursor may be pressed to adjust the film thickness or bulk density of the positive electrode active material layer. Alternatively, without the use of solvents, the positive electrode active material and lithium compound, and any other optional ingredients used as needed, are dry mixed, the resulting mixture is press molded and then conductively bonded. It is also possible to attach the agent to the positive electrode current collector.

The coating liquid of the positive electrode precursor is a dry blend of a part or all of various material powders containing a positive electrode active material, and then water or an organic solvent and / or a binder or a dispersion stabilizer is dissolved or dispersed therein. The liquid or slurry-like substance may be added and prepared. Further, a coating liquid may be prepared by adding various material powders containing a positive electrode active material to a liquid or slurry substance in which a binder or a dispersion stabilizer is dissolved or dispersed in water or an organic solvent. good. As the method of dry blending, for example, a positive electrode active material and a lithium compound are premixed using a ball mill or the like, and if necessary, a conductive filler is premixed so that the lithium compound having low conductivity is coated with the conductive filler. You may do. As a result, the lithium compound is easily decomposed in the positive electrode precursor in the lithium doping step described later. When water is used as the solvent of the coating liquid, the coating liquid may become alkaline by adding the lithium compound, so a pH adjuster may be added if necessary.

The preparation of the coating liquid for the positive electrode precursor is not particularly limited, but preferably a homodisper or a disperser such as a multi-axis disperser, a planetary mixer, a thin film swirl type high-speed mixer or the like is used. Can be done. In order to obtain a coating liquid in a good dispersed state, it is preferable to perform dispersion at a peripheral speed of 1 m / s or more and 50 m / s or less. When the peripheral speed is 1 m / s or more, various materials are preferably dissolved or dispersed. Further, when the peripheral speed is 50 m / s or less, various materials are not destroyed by heat or shearing force due to dispersion, and reaggregation does not occur, which is preferable.
The dispersity of the coating liquid is preferably such that the particle size measured by the grain gauge is 0.1 μm or more and 100 μm or less. The upper limit of the dispersity is more preferably 80 μm or less in particle size, and further preferably 50 μm or less in particle size. If the particle size is less than 0.1 μm, the size is smaller than the particle size of various material powders containing the positive electrode active material, and the material is crushed during the preparation of the coating liquid, which is not preferable. Further, when the particle size is 100 μm or less, stable coating can be performed without clogging at the time of discharging the coating liquid and generation of streaks on the coating film.

The viscosity (ηb) of the coating liquid of the positive electrode precursor is preferably 1,000 mPa · s or more and 20,000 mPa · s or less, more preferably 1,500 mPa · s or more and 10,000 mPa · s or less, still more preferably 1. , 700 mPa · s or more and 5,000 mPa · s or less. When the viscosity (ηb) is 1,000 mPa · s or more, liquid dripping during coating film formation is suppressed, and the coating film width and film thickness can be satisfactorily controlled. Further, when the viscosity (ηb) is 20,000 mPa · s or less, the pressure loss in the flow path of the coating liquid when using the coating machine is small and stable coating can be performed, and the coating film thickness is less than the desired one. Can be controlled.
The TI value (thixotropy index value) of the coating liquid is preferably 1.1 or more, more preferably 1.2 or more, and further preferably 1.5 or more. When the TI value is 1.1 or more, the coating film width and the film thickness can be satisfactorily controlled.

The formation of the coating film of the positive electrode precursor is not particularly limited, but a coating machine such as a die coater or a comma coater, a knife coater, or a gravure coating machine can be preferably used. The coating film may be formed by a single-layer coating or a multi-layer coating. In the case of multi-layer coating, the coating liquid composition may be adjusted so that the content of the lithium compound in each layer of the coating film is different. The coating speed is preferably 0.1 m / min or more and 100 m / min or less, more preferably 0.5 m / min or more and 70 m / min or less, and further preferably 1 m / min or more and 50 m / min or less. If the coating speed is 0.1 m / min or more, stable coating can be performed. On the other hand, if the coating speed is 100 m / min or less, sufficient coating accuracy can be ensured.

The drying of the coating film of the positive electrode precursor is not particularly limited, but a drying method such as hot air drying or infrared (IR) drying can be preferably used. The coating film may be dried at a single temperature, or may be dried at different temperatures in multiple stages. Further, the coating film may be dried by combining a plurality of drying methods. The drying temperature is preferably 25 ° C. or higher and 200 ° C. or lower, more preferably 40 ° C. or higher and 180 ° C. or lower, and further preferably 50 ° C. or higher and 160 ° C. or lower. When the drying temperature is 25 ° C. or higher, the solvent in the coating film can be sufficiently volatilized. On the other hand, when the drying temperature is 200 ° C. or lower, it is possible to suppress cracking of the coating film due to rapid volatilization of the solvent or uneven distribution of the binder due to migration, and oxidation of the positive electrode current collector or the positive electrode active material layer.

The press of the positive electrode precursor is not particularly limited, but a press machine such as a hydraulic press machine or a vacuum press machine can be preferably used. The film thickness, bulk density, and electrode strength of the positive electrode active material layer can be adjusted by the press pressure, the gap, and the surface temperature of the press portion, which will be described later.
The press pressure is preferably 0.5 kN / cm or more and 20 kN / cm or less, more preferably 1 kN / cm or more and 10 kN / cm or less, and further preferably 2 kN / cm or more and 7 kN / cm or less. When the press pressure is 0.5 kN / cm or more, the electrode strength can be sufficiently increased. On the other hand, when the press pressure is 20 kN / cm or less, the positive electrode precursor does not bend or wrinkle, and the desired positive electrode active material layer thickness or bulk density can be adjusted.
Further, the gap between the press rolls can be set to an arbitrary value according to the film thickness of the positive electrode precursor after drying so as to have a desired film thickness or bulk density of the positive electrode active material layer. Further, the pressing speed can be set to any speed at which the positive electrode precursor does not bend or wrinkle.
Further, the surface temperature of the press portion may be room temperature, or the press portion may be heated if necessary. The lower limit of the surface temperature of the pressed portion at the time of heating is preferably a melting point of minus 60 ° C. or higher, more preferably minus 45 ° C. or higher, and even more preferably minus 30 ° C. or higher of the melting point of the binder to be used. On the other hand, the upper limit of the surface temperature of the pressed portion when heating is preferably the melting point of the binder to be used plus 50 ° C. or lower, more preferably the melting point plus 30 ° C. or lower, and further preferably the melting point plus 20 ° C. or lower. For example, when PVdF (polyvinylidene fluoride: melting point 150 ° C.) is used as the binder, it is preferable to heat the surface of the pressed portion to 90 ° C. or higher and 200 ° C. or lower, more preferably 105 ° C. or higher and 180 ° C. or lower, and further. It is preferable to heat the surface of the press portion to 120 ° C. or higher and 170 ° C. or lower. When a styrene-butadiene copolymer (melting point 100 ° C.) is used as the binder, the surface of the pressed portion is preferably heated to 40 ° C. or higher and 150 ° C. or lower, more preferably 55 ° C. or higher and 130 ° C. or lower. More preferably, the surface of the pressed portion is heated to 70 ° C. or higher and 120 ° C. or lower.

The melting point of the binder can be determined from the endothermic peak position of DSC (Differential Scanning Calorimetry, differential scanning calorimetry). For example, using a differential scanning calorimeter "DSC7" manufactured by PerkinElmer, 10 mg of sample resin is set in a measurement cell, and the temperature rises from 30 ° C. to 250 ° C. at a temperature rise rate of 10 ° C./min in a nitrogen gas atmosphere. The temperature is raised, and the endothermic peak temperature in the temperature raising process becomes the melting point.
Further, the press may be performed a plurality of times while changing the conditions of the press pressure, the gap, the speed, and the surface temperature of the press portion.

The film thickness of the positive electrode active material layer is preferably 20 μm or more and 200 μm or less per one side of the positive electrode current collector, more preferably 25 μm or more and 100 μm or less per one side, and further preferably 30 μm or more and 80 μm or less. When this film thickness is 20 μm or more, a sufficient charge / discharge capacity can be developed. On the other hand, when this film thickness is 200 μm or less, the ion diffusion resistance in the electrode can be kept low. Therefore, sufficient output characteristics can be obtained, and the cell volume can be reduced, so that the energy density can be increased. The upper and lower limits of the film thickness range of the positive electrode active material layer can be arbitrarily combined. The film thickness of the positive electrode active material layer when the current collector has through holes or irregularities means the average value of the film thickness per side of the portion of the current collector that does not have through holes or irregularities.

[Positive electrode]
The bulk density of the positive electrode active material layer in the positive electrode after the lithium doping step described later ^{is preferably 0.25 g / cm 3} or more, more preferably 0.30 g / cm ³ or more and 1.3 g / cm ³ or less. Is. When the bulk density of the positive electrode active material layer is 0.25 g / cm ³ or more, a high energy density can be exhibited and the miniaturization of the power storage element can be achieved. On the other hand, when the bulk density is 1.3 g / cm ³ or less, the electrolytic solution is sufficiently diffused in the pores in the positive electrode active material layer, and high output characteristics can be obtained.

[Compound in positive electrode active material layer]
The positive electrode active material layer according to the present embodiment is of the formula CH ₃ OX ¹ {in the formula, X ¹ is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. } Contains a compound represented by.
Preferred compounds are CH ₃ OLi and CH ₃ OCOOLi.
Here, the total amount of the compound represented by the formula CH ₃ OX ^{1 is 5.00 × 10 -6} mol / g or more and 150.0 × 10 ^-6 mol / g or less per unit mass of the positive electrode active material layer. It is preferably 10.0 × ^10-6 mol / g or more, and more ^{preferably 100.0 × 10-6} mol / g or less. When the total amount of the compound is 5.00 × 10 ^-6 mol / g or more and 150.0 × 10 ^-6 mol / g or less, the diffusion of Li ions is not hindered and high input / output characteristics are exhibited. Can be done.

The positive electrode active material layer according to the present embodiment further has the formula C ₂ H ₅ OX ² {in the formula, X ² is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. Is. } Contains a compound represented by.
Preferred compounds are C ₂ H ₅ OLi and CH ₅ OCOOLi.
Here, the total amount of the compound represented by the formula C ₂ H ₅ OX ^{2 is 1.00 × 10-6} mol / g or more and 60.0 × ^10-6 mol / g per unit mass of the positive electrode active material layer. It is preferably 1.50 × 10 ^-6 mol / g or more, and more ^{preferably 40.0 × 10 -6} mol / g or less. When the total amount of the compound is 1.00 × ^10-6 mol / g or more and 60.0 × ^10-6 mol / g or less, the non-aqueous electrolyte solution does not come into contact with the positive electrode active material, and the non-aqueous electrolyte solution becomes It is possible to suppress the generation of gas by oxidative decomposition.

As a method for incorporating the above-mentioned compound in the positive electrode active material layer in the present invention, for example,
A method of mixing the compound with the positive electrode active material layer,
A method of adsorbing the compound on the positive electrode active material layer,
Examples thereof include a method of electrochemically precipitating the compound on the positive electrode active material layer.
Above all, a positive electrode active material layer is contained in a non-aqueous electrolyte solution that can be decomposed to produce these compounds, and the decomposition reaction of the precursor in the step of producing a power storage element is utilized. A method of depositing the compound inside is preferable.
As the precursor for forming the compound, it is preferable to use at least one organic solvent selected from dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.

In this embodiment, the formula CH ₃ OX ¹ {in the formula, X ¹ is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. } The content of the compound represented by the positive electrode material layer per unit mass is A, and the formula C ₂ H ₅ OX ² {in the formula, X ² is − (O) _n Li or − (COO) _n Li. Yes, and n is 0 or 1. } When the content per unit mass of the positive electrode material layer of the compound represented by is B, the A / B is 1.80 or more and 20.00 or less. The A / B is preferably 1.90 or more and 15.00 or less, and more preferably 2.00 or more and 8.00 or less. When the A / B is 1.80 or more, the diffusibility of Li ions at the positive electrode interface is improved, and high input / output characteristics can be maintained even in a low temperature environment. Further, when the A / B is 20.00 or less, the non-aqueous electrolytic solution is not oxidatively decomposed at the positive electrode interface to generate gas even in a high temperature environment. Therefore, when the A / B is 1.80 or more and 20.00 or less, it is possible to achieve both sufficient high temperature durability and high input / output characteristics in a low temperature environment.

Sufficient high-temperature durability and high input / output characteristics in a low-temperature environment are achieved by keeping the ratio of the lithium (Li) compound content A and the Li compound content B contained in the positive electrode active material layer within a certain range. The principle that can be achieved is not clear, but it is inferred as follows. The Li compound corresponding to the content A is a solid electrolyte membrane having high Li ion conductivity, and the diffusibility of Li ions in the positive electrode active material layer during the charge / discharge reaction can be kept good. On the other hand, the Li compound corresponding to the content B is a stable solid electrolyte membrane having high oxidation resistance, and can suppress oxidative decomposition at the positive electrode-electrolyte solution interface in a high temperature environment. By keeping the abundance ratio of these Li compounds in the positive electrode active material layer within a certain range, the diffusivity and oxidation resistance of Li ions at the positive electrode active material interface are improved, and under sufficient high temperature durability and low temperature environment. It is considered that high input / output characteristics can be achieved at the same time.

The positive electrode active material layer according to the present embodiment contains one or more compounds selected from the following formulas (1) to (3) from 1.60 × 10 ^-4 mol / g per unit mass of the positive electrode material layer. Contains 150.0 × 10 ^-4 mol / g.
LiX ^I- OR ¹ O-X ^II Li (1)
{In formula (1), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and ^XI and X ^II are independently − (COO) _n. (Here, n is 0 or 1.). }
LiX ^I- OR ¹ O-X ^II R ² (2)
{In the formula (2), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and R ² is hydrogen, an alkyl group having 1 to 10 carbon atoms, and carbon. A mono or polyhydroxyalkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a mono or polyhydroxyalkenyl group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group. And X ^I and X ^II are independently − (COO) _n (where n is 0 or 1). }
R ² X ^I- OR ¹ O-X ^II R ³ (3)
{In the formula (3), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and R ² and R ³ are independently hydrogen and 1 carbon atom, respectively. Alkyl groups of 10 to 10, mono or polyhydroxyalkyl groups with 1 to 10 carbon atoms, alkenyl groups with 2 to 10 carbon atoms, mono or polyhydroxyalkenyl groups with 2 to 10 carbon atoms, cycloalkyl groups with 3 to 6 carbon atoms , Or an aryl group, and ^XI and X ^II are independently − (COO) _n (where n is 0 or 1). }

In the formula (1), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and ^XI and X ^II are independently − (COO) _n (here). And n is 0 or 1).
The compounds represented by the formula (1) are preferably LiOC ₂ H ₄ OLi, LiOC ₃ H ₆ OLi, LiOC ₂ H ₄ OCOOLi, LiOCOOC ₃ H ₆ OLi, LiOCOOC ₂ H ₄ OCOOLi and LiOCOOC ₃ H ₆ OCOLi. be.

In the formula (2), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and R ² is hydrogen, an alkyl group having 1 to 10 carbon atoms, and a carbon number of carbon atoms. It is a mono or polyhydroxyalkyl group having 1 to 10, an alkenyl group having 2 to 10 carbon atoms, a mono or polyhydroxyalkenyl group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group. X ^I and X ^II are independently − (COO) _n (where n is 0 or 1).
The compound represented by the formula (2) is preferably LiOC ₂ H ₄ OH, LiOC ₃ H ₆ OH, LiOC ₂ H ₄ OCOOH, LiOC ₃ H ₆ OCOOH, LiOCOOC ₂ H ₄ OCOOH, LiOCOOC ₃ H ₆ OCOOH, _{LiOC 2 H 4 OCH 3, LiOC} 3 H 6 OCH 3, LiOC 2 H 4 OCOOCH 3, LiOC 3 H 6 OCOOCH 3, LiOCOOC 2 H 4 OCOOCH 3, LiOCOOC 3 H 6 OCOOCH 3, LiOC 2 H 4 OC 2 H 5 , LiOC ₃ H ₆ OC ₂ H ₅ , LiOC ₂ H ₄ OCOC ₂ H ₅ , LiOC ₃ H ₆ OCOC ₂ H ₅ , LiOCOC ₂ H ₄ OCOC ₂ H ₅ , and LiOCOC ₃ H ₆ OCOC ₂ H ₅ .

In the formula (3), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and R ² and R ³ are independently hydrogen and 1 to 4 carbon atoms, respectively. 10 alkyl groups, mono or polyhydroxyalkyl groups with 1 to 10 carbon atoms, alkenyl groups with 2 to 10 carbon atoms, mono or polyhydroxyalkenyl groups with 2 to 10 carbon atoms, cycloalkyl groups with 3 to 6 carbon atoms, Alternatively, it is an aryl group, and ^XI and X ^II are independently − (COO) _n (where n is 0 or 1).
The compound represented by the formula (3) is preferably HOC ₂ H ₄ OH, HOC ₃ H ₆ OH, HOC ₂ H ₄ OCOOH, HOC ₃ H ₆ OCOOH, HOCOC ₂ H ₄ OCOOH, HOCOC ₃ H ₆ OCOOH, _{HOC 2 H 4 OCH 3, HOC} 3 H 6 OCH 3, HOC 2 H 4 OCOOCH 3, HOC 3 H 6 OCOOCH 3, HOCOOC 2 H 4 OCOOCH 3, HOCOOC 3 H 6 OCOOCH 3, HOC 2 H 4 OC 2 H 5 _{, HOC 3 H 6 OC 2 H} 5, HOC 2 H 4 OCOOC 2 H 5, HOC 3 H 6 OCOOC 2 H 5, HOCOOC 2 H 4 OCOOC 2 H 5, HOCOOC 3 H 6 OCOOC 2 H 5, CH 3 OC 2 _{H 4 OCH 3, CH 3 OC} 3 H 6 OCH 3, CH 3 OC 2 H 4 OCOOCH 3, CH 3 OC 3 H 6 OCOOCH 3, CH 3 OCOOC 2 H 4 OCOOCH 3, CH 3 OCOOC 3 H 6 OCOOCH 3, CH ₃ OC ₂ H ₄ OC ₂ H ₅ , CH ₃ OC ₃ H ₆ OC ₂ H ₅ , CH ₃ OC ₂ H ₄ OCOC ₂ H ₅ , CH ₃ OC ₃ H ₆ OCOC ₂ H ₅ , CH ₃ OCOC ₂ H ₄ OCOC ₂ H ₅ , CH ₃ OCOC ₃ H ₆ OCOC ₂ H ₅ , C ₂ H ₅ OC ₂ H ₄ OC ₂ H ₅ , C ₂ H ₅ OC ₃ H ₆ OC ₂ H ₅ , C ₂ H ₅ OC ₂ H ₄ OCOC ₂ H ₅ , C ₂ H ₅ OC ₃ H ₆ OCOC ₂ H ₅ , C ₂ H ₅ OCOC ₂ H ₄ OCOC ₂ H ₅ , and C ₂ H ₅ OCOC ₃ H ₆ OCOC ₂ H ₅ .

As a method for incorporating the compounds represented by the formulas (1) to (3) in the positive electrode active material layer, for example,
A method of mixing the compound with the positive electrode active material layer,
A method of adsorbing the compound on the positive electrode active material layer,
Examples thereof include a method of electrochemically precipitating the compound on the positive electrode active material layer.
Above all, in the positive electrode active material layer, a precursor capable of decomposing to produce these compounds is contained in the non-aqueous electrolyte solution, and the decomposition reaction of the precursor in the step of producing the power storage element is utilized. The method of depositing the compound on the surface is preferable.

As a precursor for forming the compound represented by the formulas (1) to (3), at least one organic solvent selected from the group consisting of ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate and fluoroethylene carbonate is used. It is preferable to use, and it is more preferable to use ethylene carbonate and propylene carbonate.

The total content C of the compounds represented by the formulas (1) to (3) in the positive electrode active material layer is 1.60 × 10 ^-4 mol / g or more per unit mass of the positive electrode active material layer. It is preferably 5.00 × 10 ^-4 mol / g or more. When the total content C of the compound is 1.60 × 10 ^-4 mol / g or more per unit mass of the positive electrode active material layer, the non-aqueous electrolyte solution does not come into contact with the positive electrode active material, and the non-aqueous electrolyte solution becomes It is possible to suppress the generation of gas by oxidative decomposition.
The total content C of the compound is 150.0 × 10 ^-4 mol / g or less and 130.0 × 10 ^-4 mol / g or less per unit mass of the positive electrode active material layer. It is preferably 100.0 × 10 ^-4 mol / g or less, and more preferably 100.0 × 10 -4 mol / g or less. When the total content C of the compound is 150.0 × 10 ^-4 mol / g or less per unit mass of the positive electrode active material layer, the diffusion of Li ions is not hindered and high input / output characteristics are exhibited. Can be done.

[Negative electrode]
The negative electrode has a negative electrode current collector and a negative electrode active material layer existing on one side or both sides thereof.

[Negative electrode active material layer]
The negative electrode active material layer contains a negative electrode active material that can occlude and release lithium ions. In addition to this, the negative electrode active material layer may contain an optional component such as a conductive filler, a binder, and a dispersion stabilizer, if necessary.

[Negative electrode active material]
As the negative electrode active material, a substance capable of storing and releasing lithium ions can be used. Specific examples thereof include carbon materials, titanium oxides, silicon, silicon oxides, silicon alloys, silicon compounds, tin and tin compounds. The content of the carbon material with respect to the total amount of the negative electrode active material is preferably 50% by mass or more, and more preferably 70% by mass or more. The content of the carbon material may be 100% by mass, but from the viewpoint of obtaining a good effect by using other materials in combination, for example, it is preferably 90% by mass or less, and preferably 80% by mass or less.

The negative electrode active material is preferably doped with lithium ions. In the present specification, the lithium ions doped in the negative electrode active material mainly include three forms.
The first form is lithium ions that are occluded in advance as a design value in the negative electrode active material before the non-aqueous lithium-type power storage element is manufactured.
The second form is lithium ions occluded in the negative electrode active material when a non-aqueous lithium-type power storage element is manufactured and shipped.
The third form is lithium ions occluded in the negative electrode active material after the non-aqueous lithium-type power storage element is used as a device.
By doping the negative electrode active material with lithium ions, it is possible to satisfactorily control the capacity and operating voltage of the obtained non-aqueous lithium-type power storage element.

Examples of the carbon material include non-graphitizable carbon materials; easily graphitizable carbon materials; carbon black; carbon nanoparticles; activated carbon; artificial graphite; natural graphite; graphitized mesophase carbon globules; graphite whiskers; polyacene-based substances. Amorphous carbonaceous materials such as; petroleum-based pitches, coal-based pitches, carbonaceous materials such as mesocarbon microbeads, coke, synthetic resins (eg, phenolic resins, etc.) Carbonated materials obtained by heat treatment of precursors; full Thermal decomposition products of frill alcohol resin or novolak resin; fullerene; carbon nanophones; and composite carbon materials thereof can be mentioned.

Among these, from the viewpoint of lowering the resistance of the negative electrode, heat treatment is performed in a state where one or more of the carbon materials (hereinafter, also referred to as a base material) and the carbonaceous material precursor coexist, and the base material and the carbon are coexisted. A composite carbon material obtained by combining a carbon material derived from a quality material precursor is preferable. The carbonaceous material precursor is not particularly limited as long as it becomes the carbonaceous material by heat treatment, but a petroleum-based pitch or a coal-based pitch is particularly preferable. The substrate and the carbonaceous material precursor may be mixed at a temperature higher than the melting point of the carbonaceous material precursor before the heat treatment. The heat treatment temperature may be any temperature as long as the component generated by volatilization or thermal decomposition of the carbonaceous material precursor to be used becomes the carbonaceous material, but is preferably 400 ° C. or higher and 2500 ° C. or lower, more preferably 500 ° C. It is 2000 ° C. or lower, more preferably 550 ° C. or higher and 1500 ° C. or lower. The atmosphere in which the heat treatment is performed is not particularly limited, but a non-oxidizing atmosphere is preferable.

Preferred examples of the composite carbon material are composite carbon materials 1 and 2 described later. Either of these may be selected and used, or both of them may be used in combination.

[Composite carbon material 1]
The composite carbon material 1 is the composite carbon material using one ^{or more carbon materials having a BET specific surface area of 100 m 2} / g or more and 3000 m ² / g or less as the base material. The base material is not particularly limited, but activated carbon, carbon black, template porous carbon, high specific surface area graphite, carbon nanoparticles and the like can be preferably used.

The BET specific surface area of the composite carbon material 1 ^{is preferably 100 m 2} / g or more and 1,500 m ² / g or less, more preferably 150 m ² / g or more and 1,100 m ² / g or less, and further preferably 180 m ² / g or more and 550 m. ^{It is 2} / g or less. When the BET specific surface area is 100 m ² / g or more, the pores can be appropriately retained and the diffusion of lithium ions becomes good, so that high input / output characteristics can be exhibited. On the other hand, when the BET specific surface area is 1,500 m ² / g or less, the charge / discharge efficiency of lithium ions is improved, so that the cycle durability is not impaired.

The mass ratio of the carbonaceous material to the base material in the composite carbon material 1 is preferably 10% by mass or more and 200% by mass or less. This mass ratio is more preferably 12% by mass or more and 180% by mass or less, further preferably 15% by mass or more and 160% by mass or less, and particularly preferably 18% by mass or more and 150% by mass or less. When the mass ratio of the carbonaceous material is 10% by mass or more, the micropores of the base material can be appropriately filled with the carbonic material, and the charge / discharge efficiency of lithium ions is improved, which is good. Cycle durability can be shown. Further, when the mass ratio of the carbonaceous material is 200% by mass or less, the pores can be appropriately retained and the diffusion of lithium ions becomes good, so that high input / output characteristics can be exhibited.

The doping amount of lithium ions per unit mass of the composite carbon material 1 is preferably 530 mAh / g or more and 2,500 mAh / g or less. The doping amount is more preferably 620 mAh / g or more and 2,100 mAh / g or less, further preferably 760 mAh / g or more and 1,700 mAh / g or less, and particularly preferably 840 mAh / g or more and 1,500 mAh / g or less.
Doping lithium ions lowers the negative electrode potential. Therefore, when the negative electrode containing the lithium ion-doped composite carbon material 1 is combined with the positive electrode, the voltage of the non-aqueous lithium-type power storage element becomes high and the utilization capacity of the positive electrode becomes large. Therefore, the capacity and energy density of the obtained non-aqueous lithium-type power storage element are increased.
When the doping amount is 530 mAh / g or more, the lithium ions are well doped in the irreversible sites that cannot be desorbed once the lithium ions in the composite carbon material 1 are inserted, and the composite carbon material 1 with respect to the desired lithium amount is further doped. The amount of can be reduced. Therefore, the film thickness of the negative electrode can be reduced, and a high energy density can be obtained. As the doping amount increases, the negative electrode potential decreases, and the input / output characteristics, energy density, and durability are improved.
On the other hand, when the doping amount is 2,500 mAh / g or less, there is no possibility that side effects such as precipitation of lithium metal will occur.

Hereinafter, as a preferable example of the composite carbon material 1, the composite carbon material 1a using activated carbon as the base material will be described.
The composite carbon material 1a has a mesopore amount of Vm1 (cc / g) derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by the BJH method, and a micropore amount derived from pores having a diameter of less than 20 Å calculated by the MP method. When is Vm2 (cc / g), it is preferable that 0.010 ≦ Vm1 ≦ 0.300 and 0.001 ≦ Vm2 ≦ 0.650.
The mesopore amount Vm1 is more preferably 0.010 ≦ Vm1 ≦ 0.225, and further preferably 0.010 ≦ Vm1 ≦ 0.200. The micropore amount Vm2 is more preferably 0.001 ≦ Vm2 ≦ 0.200, further preferably 0.001 ≦ Vm2 ≦ 0.150, and particularly preferably 0.001 ≦ Vm2 ≦ 0.100.

When the mesopore amount Vm1 is 0.300 cc / g or less, the BET specific surface area can be increased, the doping amount of lithium ions can be increased, and the bulk density of the negative electrode can be increased. As a result, the negative electrode can be thinned. Further, when the micropore amount Vm2 is 0.650 cc / g or less, high charge / discharge efficiency for lithium ions can be maintained. On the other hand, when the mesopore amount Vm1 and the micropore amount Vm2 are equal to or higher than the lower limit (0.010 ≦ Vm1, 0.001 ≦ Vm2), high input / output characteristics can be obtained.

The BET specific surface area of the composite carbon material 1a ^{is preferably 100 m 2} / g or more and 1,500 m ² / g or less. It is more preferably 150 m ² / g or more and 1,100 m ² / g or less, and further preferably 180 m ² / g or more and 550 m ² / g or less. When the BET specific surface area is 100 m ² / g or more, the pores can be appropriately retained, and the diffusion of lithium ions becomes good, so that high input / output characteristics can be exhibited. Further, since the doping amount of lithium ions can be increased, the negative electrode can be thinned. On the other hand, when it is 1,500 m ² / g or less, the charge / discharge efficiency of lithium ions is improved, so that the cycle durability is not impaired.

The average pore diameter of the composite carbon material 1a is preferably 20 Å or more, more preferably 25 Å or more, and even more preferably 30 Å or more, from the viewpoint of obtaining high input / output characteristics. On the other hand, from the viewpoint of increasing the energy density, the average pore diameter is preferably 65 Å or less, and more preferably 60 Å or less.

The average particle size of the composite carbon material 1a is preferably 1 μm or more and 10 μm or less. The lower limit is more preferably 2 μm or more, still more preferably 2.5 μm or more. The upper limit is more preferably 6 μm or less, still more preferably 4 μm or less. Good durability is maintained when the average particle size is 1 μm or more and 10 μm or less.

The atomic number ratio (H / C) of the hydrogen atom / carbon atom of the composite carbon material 1a is preferably 0.05 or more and 0.35 or less, and more preferably 0.05 or more and 0.15 or less. When the H / C is 0.35 or less, the structure of the carbonaceous material adhered to the surface of the activated carbon (typically, the polycyclic aromatic conjugate structure) is well developed and the capacity (energy). Density) and charge / discharge efficiency increase. On the other hand, when the H / C is 0.05 or more, carbonization does not proceed excessively, so that a good energy density can be obtained. H / C is measured by an elemental analyzer.

The composite carbon material 1a has an amorphous structure derived from the activated carbon of the base material, and at the same time, has a crystal structure mainly derived from the adhered carbonaceous material. According to the X-ray wide-angle diffraction method, the composite carbon material 1a has a (002) plane spacing d002 of 3.60 Å or more and 4.00 Å or less, and crystallites in the c-axis direction obtained from the half width of this peak. The size Lc is preferably 8.0 Å or more and 20.0 Å or less, d002 is 3.60 Å or more and 3.75 Å or less, and the crystallite size Lc in the c-axis direction obtained from the half width of this peak is 11. More preferably, it is 0 Å or more and 16.0 Å or less.

The activated carbon used as the base material of the composite carbon material 1a is not particularly limited as long as the obtained composite carbon material 1a exhibits desired properties. For example, commercially available products obtained from various raw materials such as petroleum-based, coal-based, plant-based, and polymer-based can be used. In particular, it is preferable to use activated carbon powder having an average particle size of 1 μm or more and 15 μm or less. The average particle size is more preferably 2 μm or more and 10 μm or less.

In order to obtain the composite carbon material 1a having the pore distribution range specified in the present embodiment, the pore distribution of the activated carbon used for the base material is important.
In the activated carbon, the amount of mesopores derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by the BJH method is V1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 Å calculated by the MP method is defined. When V2 (cc / g) is set, it is preferable that 0.050 ≦ V1 ≦ 0.500, 0.005 ≦ V2 ≦ 1.000, and 0.2 ≦ V1 / V2 ≦ 20.0.

Regarding the mesopore amount V1, 0.050 ≦ V1 ≦ 0.350 is more preferable, and 0.100 ≦ V1 ≦ 0.300 is even more preferable. Regarding the micropore amount V2, 0.005 ≦ V2 ≦ 0.850 is more preferable, and 0.100 ≦ V2 ≦ 0.800 is even more preferable. Regarding the ratio of the amount of mesopores / the amount of micropores, 0.22 ≦ V1 / V2 ≦ 15.0 is more preferable, and 0.25 ≦ V1 / V2 ≦ 10.0 is even more preferable. When the mesopore amount V1 of the activated carbon is 0.500 or less and the micropore amount V2 is 1.000 or less, an appropriate amount of carbonaceous material is obtained in order to obtain the pore structure of the composite carbon material 1a in the present embodiment. Since it is sufficient to adhere the material, it becomes easy to control the pore structure. On the other hand, when the mesopore amount V1 of the activated carbon is 0.050 or more, the micropore amount V2 is 0.005 or more, V1 / V2 is 0.2 or more, and V1 / V2 is 20.0. The structure can be easily obtained even in the following cases.

The carbonaceous material precursor used as the raw material of the composite carbon material 1a is a solid, liquid, or solvent-soluble organic material capable of adhering the carbonic material to the activated carbon by heat treatment. .. Examples of the carbonaceous material precursor include pitch, mesocarbon microbeads, coke, synthetic resin (for example, phenol resin, etc.) and the like. Among these carbonaceous material precursors, it is preferable to use an inexpensive pitch in terms of manufacturing cost. Pitches are roughly divided into petroleum-based pitches and coal-based pitches. Examples of petroleum-based pitches include distillation residue of crude oil, fluid contact decomposition residue (decant oil, etc.), bottom oil derived from thermal crackers, ethylene tar obtained during naphtha cracking, and the like.

When the above pitch is used, the pitch is heat-treated in the coexistence with the activated carbon, and the volatile component or the pyrolysis component of the pitch is thermally reacted on the surface of the activated carbon to coat the activated carbon with a carbonaceous material, whereby composite carbon is used. Material 1a is obtained. In this case, the adhesion of the volatile component or the thermal decomposition component of the pitch into the activated carbon pores proceeds at a temperature of about 200 to 500 ° C., and the reaction in which the adhered component becomes a carbonaceous material proceeds at 400 ° C. or higher. do. The peak temperature (maximum temperature reached) during the heat treatment is appropriately determined depending on the characteristics of the obtained composite carbon material 1a, the thermal reaction pattern, the thermal reaction atmosphere, etc., but is preferably 400 ° C. or higher, more preferably 400 ° C. or higher. Is 450 ° C. to 1,000 ° C., more preferably about 500 to 800 ° C. The time for maintaining the peak temperature during the heat treatment is preferably 30 minutes to 10 hours, more preferably 1 hour to 7 hours, and further preferably 2 hours to 5 hours. For example, when heat-treating at a peak temperature of about 500 to 800 ° C. for 2 hours to 5 hours, it is considered that the carbonaceous material adhered to the surface of the activated carbon is a polycyclic aromatic hydrocarbon. ..

The softening point of the pitch used is preferably 30 ° C. or higher and 250 ° C. or lower, and more preferably 60 ° C. or higher and 130 ° C. or lower. A pitch having a softening point of 30 ° C. or higher does not hinder handleability and can be charged with high accuracy. The pitch at which the softening point is 250 ° C. or lower contains a large amount of relatively low molecular weight compounds, and therefore, when the pitch is used, even fine pores in the activated carbon can be adhered.
As a specific method for producing the above-mentioned composite carbon material 1a, for example, the activated carbon is heat-treated in an inert atmosphere containing a hydrocarbon gas volatilized from the carbonaceous material precursor, and the carbonic material is covered with a vapor phase. There is a method of dressing. Further, a method in which the activated carbon and the carbonaceous material precursor are mixed in advance and heat-treated, or a method in which the carbonic material precursor dissolved in a solvent is applied to the activated carbon, dried, and then heat-treated is also possible.

It is preferable that the mass ratio of the carbonaceous material to the activated carbon in the composite carbon material 1a is 10% by mass or more and 100% by mass or less. This mass ratio is preferably 15% by mass or more and 80% by mass or less. When the mass ratio of the carbonaceous material is 10% by mass or more, the micropores of the activated carbon can be appropriately filled with the carbonic material, and the charge / discharge efficiency of lithium ions is improved, so that the cycle durability is improved. The sex is not impaired. Further, when the mass ratio of the carbonaceous material is 100% by mass or less, the pores of the composite carbon material 1a are appropriately retained and the specific surface area is maintained large. Therefore, from the result that the doping amount of lithium ions can be increased, high output density and high durability can be maintained even if the negative electrode is thinned.

[Composite carbon material 2]
The composite carbon material 2 is the composite carbon material ^{using one or more carbon materials having a BET specific surface area of 0.5 m 2} / g or more and 80 m ² / g or less as the base material. The base material is not particularly limited, but natural graphite, artificial graphite, low crystalline graphite, hard carbon, soft carbon, carbon black and the like can be preferably used.

BET specific surface area of the composite carbon material 2, ^{1 m} 2 / g or more ^{50 m} 2 / g or less, more preferably 1.5 m ² / g or more ^{40 m} 2 / g or less, more preferably ^2m 2 / g or more ^{25 m} 2 / It is less than or equal to g. When the BET specific surface area is 1 m ² / g or more, a sufficient reaction field with lithium ions can be secured, so that high input / output characteristics can be exhibited. On the other hand, when the BET specific surface area is 50 m ² / g or less, the charge / discharge efficiency of lithium ions is improved and the decomposition reaction of the non-aqueous electrolyte solution during charge / discharge is suppressed, so that high cycle durability is exhibited. Can be done.

The average particle size of the composite carbon material 2 is preferably 1 μm or more and 10 μm or less. The average particle size is more preferably 2 μm or more and 8 μm or less, and further preferably 3 μm or more and 6 μm or less. When the average particle size is 1 μm or more, the charge / discharge efficiency of lithium ions can be improved, so that high cycle durability can be exhibited. On the other hand, when the average particle size is 10 μm or less, the reaction area between the composite carbon material 2 and the non-aqueous electrolyte solution increases, so that high input / output characteristics can be exhibited.

The mass ratio of the carbonaceous material to the base material in the composite carbon material 2 is preferably 1% by mass or more and 30% by mass or less. This mass ratio is more preferably 1.2% by mass or more and 25% by mass or less, and further preferably 1.5% by mass or more and 20% by mass or less. When the mass ratio of the carbonaceous material is 1% or more by mass, the carbonaceous material can sufficiently increase the reaction sites with lithium ions, and the desolvation of lithium ions becomes easy, so that high input / output characteristics can be obtained. Can be shown. On the other hand, when the mass ratio of the carbonaceous material is 30% by mass or less, the diffusion of lithium ions between the carbonic material and the base material in the solid can be well maintained, so that high input / output characteristics can be exhibited. You can. Moreover, since the charge / discharge efficiency of lithium ions can be improved, high cycle durability can be exhibited.

The doping amount of lithium ions per unit mass of the composite carbon material 2 is preferably 50 mAh / g or more and 700 mAh / g or less, more preferably 70 mAh / g or more and 650 mAh / g or less, and further preferably 90 mAh / g or more and 600 mAh or less. / G or less, particularly preferably 100 mAh / g or more and 550 mAh / g or less.
Doping lithium ions lowers the negative electrode potential. Therefore, when the negative electrode containing the lithium ion-doped composite carbon material 2 is combined with the positive electrode, the voltage of the non-aqueous lithium-type power storage element becomes high and the utilization capacity of the positive electrode becomes large. Therefore, the capacity and energy density of the obtained non-aqueous lithium-type power storage element are increased.
When the doping amount is 50 mAh / g or more, lithium ions are satisfactorily doped even at irreversible sites that cannot be desorbed once the lithium ions in the composite carbon material 2 are inserted, so that a high energy density can be obtained. As the doping amount increases, the negative electrode potential decreases, and the input / output characteristics, energy density, and durability are improved.
On the other hand, if the doping amount is 700 mAh / g or less, there is no possibility that side effects such as precipitation of lithium metal will occur.

Hereinafter, as a preferable example of the composite carbon material 2, the composite carbon material 2a using a graphite material as the base material will be described.

The average particle size of the composite carbon material 2a is preferably 1 μm or more and 10 μm or less. The average particle size is more preferably 2 μm or more and 8 μm or less, and further preferably 3 μm or more and 6 μm or less. When the average particle size is 1 μm or more, the charge / discharge efficiency of lithium ions can be improved, so that high cycle durability can be exhibited. On the other hand, if it is 10 μm or less, the reaction area between the composite carbon material 2a and the non-aqueous electrolyte solution increases, so that high input / output characteristics can be exhibited.

The BET specific surface area of the composite carbon material 2a ^{is preferably 1 m 2} / g or more and 20 m ² / g or less, and more preferably 1 m ² / g or more and 15 m ² / g or less. When the BET specific surface area is 1 m ² / g or more, a sufficient reaction field with lithium ions can be secured, so that high input / output characteristics can be exhibited. On the other hand, when the BET specific surface area is 20 m ² / g or less, the charge / discharge efficiency of lithium ions is improved and the decomposition reaction of the non-aqueous electrolyte solution during charge / discharge is suppressed, so that high cycle durability is exhibited. Can be done.

The graphite material used as the base material is not particularly limited as long as the obtained composite carbon material 2a exhibits desired properties. For example, artificial graphite, natural graphite, graphitized mesophase carbon spherules, graphite whiskers and the like can be used. The average particle size of the graphite material is preferably 1 μm or more and 10 μm or less, and more preferably 2 μm or more and 8 μm or less.

The carbonaceous material precursor used as the raw material of the composite carbon material 2a is an organic material that can be dissolved in a solid, liquid, or solvent, in which the carbonaceous material can be composited with the graphite material by heat treatment. .. Examples of the carbonaceous material precursor include pitch, mesocarbon microbeads, coke, synthetic resin (for example, phenol resin, etc.) and the like. Among these carbonaceous material precursors, it is preferable to use an inexpensive pitch in terms of manufacturing cost. Pitches are roughly divided into petroleum-based pitches and coal-based pitches. Examples of petroleum-based pitches include distillation residue of crude oil, fluid contact decomposition residue (decant oil, etc.), bottom oil derived from thermal crackers, ethylene tar obtained during naphtha cracking, and the like.

The mass ratio of the carbonaceous material to the graphite material in the composite carbon material 2a is preferably 1% by mass or more and 10% by mass or less. This mass ratio is more preferably 1.2% by mass or more and 8% by mass or less, further preferably 1.5% by mass or more and 6% by mass or less, and particularly preferably 2% by mass or more and 5% by mass or less. When the mass ratio of the carbonaceous material is 1% by mass or more, the carbonaceous material can sufficiently increase the reaction sites with lithium ions, and the desolvation of lithium ions becomes easy, so that high input / output characteristics can be obtained. Can be shown. On the other hand, when the mass ratio of the carbonaceous material is 10% by mass or less, the diffusion of lithium ions between the carbonic material and the graphite material in the solid can be well maintained, so that high input / output characteristics can be exhibited. You can. Moreover, since the charge / discharge efficiency of lithium ions can be improved, high cycle durability can be exhibited.

The negative electrode active material layer in the present invention may contain an optional component such as a conductive filler, a binder, and a dispersion stabilizer in addition to the negative electrode active material, if necessary.
The type of the conductive filler is not particularly limited, and examples thereof include acetylene black, ketjen black, and vapor-grown carbon fiber. The amount of the conductive filler used is preferably 0 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the negative electrode active material. It is more preferably 0 parts by mass or more and 20 parts by mass or less, and further preferably 0 parts by mass or more and 15 parts by mass or less.

The binder is not particularly limited, but for example, PVdF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), polyimide, latex, styrene-butadiene copolymer, fluororubber, acrylic copolymer and the like. Can be used. The amount of the binder used is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 2 parts by mass or more and 27 parts by mass or less, and further preferably 3 parts by mass or more with respect to 100 parts by mass of the negative electrode active material. It is 25 parts by mass or less. When the amount of the binder is 1 part by mass or more, sufficient electrode strength is exhibited. On the other hand, when the amount of the binder is 30 parts by mass or less, high input / output characteristics are exhibited without inhibiting the entry and exit of lithium ions into the negative electrode active material.

The dispersion stabilizer is not particularly limited, but for example, PVP (polyvinylpyrrolidone), PVA (polyvinyl alcohol), a cellulose derivative and the like can be used. The amount of the dispersion stabilizer used is preferably 0 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the negative electrode active material. When the amount of the dispersion stabilizer is 10 parts by mass or less, high input / output characteristics are exhibited without inhibiting the entry and exit of lithium ions into the negative electrode active material.

[Negative electrode current collector]
The material constituting the negative electrode current collector in the present invention is preferably a metal foil having high electron conductivity and not deteriorating due to elution into a non-aqueous electrolyte solution and reaction with an electrolyte or ions. Such metal foil is not particularly limited, and examples thereof include aluminum foil, copper foil, nickel foil, and stainless steel foil. Copper foil is preferable as the negative electrode current collector in the non-aqueous lithium power storage device according to the present embodiment.
The metal foil may be a normal metal foil having no irregularities or through holes, a metal foil having irregularities subjected to embossing, chemical etching, electrolytic precipitation, blasting, etc., expanded metal, punching metal, etc. , A metal foil having through holes such as an etching foil may be used.
From the viewpoint of ease of electrode production and high electron conductivity, the negative electrode current collector in the present embodiment is preferably non-porous. In the specification of the present application, the “non-porous negative electrode current collector” means that lithium ions pass through the negative electrode current collector and the lithium ions are uniform on the front and back surfaces of the negative electrode, at least in the coated region of the negative electrode active material layer. It means a negative electrode current collector that does not have enough holes to be converted. Therefore, within the range in which the effect of the present invention is exhibited, the negative electrode current collector having extremely small diameter or a small amount of holes and the negative electrode current collector having holes in the uncoated region of the negative electrode active material layer are also excluded. is not it. Further, in the present embodiment, at least the region of the negative electrode current collector coated with the negative electrode active material layer is non-porous, and the excess portion of the negative electrode current collector where the negative electrode active material layer is not coated is covered. May or may not have holes.
The thickness of the negative electrode current collector is not particularly limited as long as the shape and strength of the negative electrode can be sufficiently maintained, but is preferably 1 to 100 μm, for example. When the negative electrode current collector has holes or irregularities, the thickness of the negative electrode current collector shall be measured based on the portion where the holes or irregularities do not exist.

[Manufacturing of negative electrode]
The negative electrode has a negative electrode active material layer on one side or both sides of the negative electrode current collector. In a typical embodiment, the negative electrode active material layer is fixed to the negative electrode current collector.
The negative electrode can be manufactured by a technique for manufacturing electrodes in known lithium ion batteries, electric double layer capacitors and the like. For example, various materials including the negative electrode active material are dispersed or dissolved in water or an organic solvent to prepare a slurry coating liquid, and this coating liquid is applied to one or both sides of the negative electrode current collector. A negative electrode can be obtained by forming a coating film and drying it. Further, the obtained negative electrode may be pressed to adjust the film thickness or bulk density of the negative electrode active material layer. Alternatively, a method in which various materials including a negative electrode active material are mixed in a dry manner without using a solvent, the obtained mixture is press-molded, and then attached to a negative electrode current collector using a conductive adhesive. Is also possible.

The coating liquid is prepared by dry-blending a part or all of various material powders including the negative electrode active material, and then water or an organic solvent and / or a liquid in which a binder or a dispersion stabilizer is dissolved or dispersed therein. A slurry-like substance may be added and prepared. Further, various material powders containing a negative electrode active material may be added to a liquid or slurry substance in which a binder or a dispersion stabilizer is dissolved or dispersed in water or an organic solvent. Although the preparation of the coating liquid is not particularly limited, a homodisper or a disperser such as a multi-axis disperser, a planetary mixer, or a thin film swirling high-speed mixer can be preferably used. In order to obtain a coating liquid in a well-dispersed state, it is preferable to disperse at a peripheral speed of 1 m / s or more and 50 m / s or less. A peripheral speed of 1 m / s or more is preferable because various materials are satisfactorily dissolved or dispersed. Further, when the peripheral speed is 50 m / s or less, various materials are not destroyed by heat or shearing force due to dispersion, and reaggregation does not occur, which is preferable.

The viscosity (ηb) of the coating liquid is preferably 1,000 mPa · s or more and 20,000 mPa · s or less, more preferably 1,500 mPa · s or more and 10,000 mPa · s or less, and further preferably 1,700 mPa · s. It is 5,000 mPa · s or less. When the viscosity (ηb) is 1,000 mPa · s or more, liquid dripping during coating film formation is suppressed, and the coating film width and film thickness can be satisfactorily controlled. Further, when it is 20,000 mPa · s or less, the pressure loss in the flow path of the coating liquid when using the coating machine is small and stable coating can be performed, and the coating film thickness can be controlled to be less than the desired coating film thickness.
The TI value (thixotropy index value) of the coating liquid is preferably 1.1 or more, more preferably 1.2 or more, and further preferably 1.5 or more. When the TI value is 1.1 or more, the coating film width and the film thickness can be satisfactorily controlled.

The formation of the coating film is not particularly limited, but a coating machine such as a die coater or a comma coater, a knife coater, or a gravure coating machine can be preferably used. The coating film may be formed by a single-layer coating or a multi-layer coating. The coating speed is preferably 0.1 m / min or more and 100 m / min or less, more preferably 0.5 m / min or more and 70 m / min or less, and further preferably 1 m / min or more and 50 m / min or less. If the coating speed is 0.1 m / min or more, stable coating can be performed. On the other hand, if the coating speed is 100 m / min or less, sufficient coating accuracy can be ensured.

The drying of the coating film is not particularly limited, but a drying method such as hot air drying or infrared (IR) drying can be preferably used. The coating film may be dried at a single temperature, or may be dried at different temperatures in multiple stages. Moreover, you may dry by combining a plurality of drying methods. The drying temperature is preferably 25 ° C. or higher and 200 ° C. or lower, more preferably 40 ° C. or higher and 180 ° C. or lower, and further preferably 50 ° C. or higher and 160 ° C. or lower. When the drying temperature is 25 ° C. or higher, the solvent in the coating film can be sufficiently volatilized. On the other hand, when the drying temperature is 200 ° C. or lower, it is possible to suppress cracking of the coating film due to rapid volatilization of the solvent or uneven distribution of the binder due to migration, and oxidation of the negative electrode current collector or the negative electrode active material layer.

The press of the negative electrode is not particularly limited, but a press machine such as a hydraulic press machine or a vacuum press machine can be preferably used. The film thickness, bulk density, and electrode strength of the negative electrode active material layer can be adjusted by the press pressure, the gap, the surface temperature of the press portion, and the like, which will be described later. The press pressure is preferably 0.5 kN / cm or more and 20 kN / cm or less, more preferably 1 kN / cm or more and 10 kN / cm or less, and further preferably 2 kN / cm or more and 7 kN / cm or less. When the press pressure is 0.5 kN / cm or more, the electrode strength can be sufficiently increased. On the other hand, when the press pressure is 20 kN / cm or less, the negative electrode does not bend or wrinkle, and the film thickness or bulk density of the negative electrode active material can be adjusted to a desired value. Further, the gap between the press rolls can be set to an arbitrary value according to the film thickness of the negative electrode after drying so as to have a desired film thickness or bulk density of the negative electrode active material layer. Further, the pressing speed can be set to any speed at which the negative electrode does not bend or wrinkle. Further, the surface temperature of the pressed portion may be room temperature or may be heated if necessary. The lower limit of the surface temperature of the pressed portion at the time of heating is preferably the melting point of the binder used at minus 60 ° C. or higher, more preferably 45 ° C. or higher, still more preferably 30 ° C. or higher. On the other hand, the upper limit of the surface temperature of the pressed portion when heating is preferably the melting point of the binder used plus 50 ° C. or lower, more preferably 30 ° C. or lower, and further preferably 20 ° C. or lower. For example, when PVdF (polyvinylidene fluoride: melting point 150 ° C.) is used as the binder, it is preferable to heat it to 90 ° C. or higher and 200 ° C. or lower. It is more preferably 105 ° C. or higher and 180 ° C. or lower, and further preferably 120 ° C. or higher and 170 ° C. or lower. When a styrene-butadiene copolymer (melting point 100 ° C.) is used as the binder, it is preferable to heat the mixture to 40 ° C. or higher and 150 ° C. or lower. It is more preferably 55 ° C. or higher and 130 ° C. or lower, and further preferably 70 ° C. or higher and 120 ° C. or lower.

The melting point of the binder can be determined from the endothermic peak position of DSC (Differential Scanning Calorimetry, differential scanning calorimetry). For example, using a differential scanning calorimeter "DSC7" manufactured by PerkinElmer, 10 mg of sample resin is set in a measurement cell, and the temperature rises from 30 ° C. to 250 ° C. at a temperature rise rate of 10 ° C./min in a nitrogen gas atmosphere. The temperature is raised, and the endothermic peak temperature in the temperature raising process becomes the melting point.
Further, the press may be performed a plurality of times while changing the conditions of the press pressure, the gap, the speed, and the surface temperature of the press portion.

[Measurement item]
The BET specific surface area, the average pore diameter, the mesopore amount, and the micropore amount in the present specification are values obtained by the following methods, respectively. The sample is vacuum-dried at 200 ° C. for 24 hours, and the isotherms of adsorption and desorption are measured using nitrogen as an adsorbent. Using the adsorption-side isotherm obtained here, the BET specific surface area is the BET multi-point method or the BET one-point method, and the average pore diameter is the mesopores by dividing the total pore volume per mass by the BET specific surface area. The amount is calculated by the BJH method, and the amount of micropores is calculated by the MP method.
The BJH method is a calculation method generally used for analysis of mesopores, and has been proposed by Barrett, Joiner, Hallenda et al. (Non-Patent Document 1).
The MP method means a method of obtaining the micropore volume, the micropore area, and the distribution of the micropores by using the "t-plot method" (Non-Patent Document 2). S. This is a method devised by Mikhair, Brunauer, and Bodor (Non-Patent Document 3).

The average particle size in the present specification is the particle size at the point where the cumulative curve is 50% when the cumulative curve is obtained with the total product as 100% when the particle size distribution is measured using the particle size distribution measuring device (that is,). , 50% diameter (Median diameter)). This average particle size can be measured using a commercially available laser diffraction type particle size distribution measuring device.

The amount of lithium ion doped in the negative electrode active material in the non-aqueous lithium-type power storage device at the time of shipment and after use in the present specification can be known, for example, as follows.
First, the negative electrode active material layer in the present embodiment is washed with ethyl methyl carbonate or dimethyl carbonate and air-dried, and then an extract extracted with a mixed solvent consisting of methanol and isopropanol and an extracted negative electrode active material layer are obtained. This extraction is typically performed in an Ar box at an environmental temperature of 23 ° C.
The amount of lithium contained in the extract obtained as described above and the negative electrode active material layer after extraction is quantified using, for example, ICP-MS (inductively coupled plasma mass spectrometer), and the amount thereof is quantified. By obtaining the total, the amount of lithium ion doped in the negative electrode active material can be known. Then, the obtained value may be allocated by the amount of the negative electrode active material used for extraction, and the numerical value of the above unit may be calculated.

The primary particle size in the present specification is about 2,000 to 3,000 particles obtained by photographing the powder in several fields with an electron microscope and using a fully automatic image processing device or the like to measure the particle size of the particles in those fields. It can be obtained by measuring and using the value obtained by arithmetically averaging these as the primary particle size.

In the present specification, the dispersity is a value obtained by a dispersity evaluation test using a grain gauge specified in JIS K5600. That is, a sufficient amount of sample is poured into the tip of the deeper groove of the grain gauge having a groove of a desired depth according to the size of the grain, and the sample is slightly overflowed from the groove. Next, the long side of the scraper becomes parallel to the width direction of the gauge, and the cutting edge is placed so as to contact the deep tip of the groove of the grain gauge, and the scraper is held so as to be the surface of the gauge while the long side direction of the groove. Pull the surface of the gauge at a right angle to the groove depth of 0 at a uniform speed for 1 to 2 seconds, and shine light at an angle of 20 ° to 30 ° within 3 seconds after the pulling is completed. Observe and read the depth at which the grains appear in the grooves of the grain gauge.

The viscosity (ηb) and TI value in the present specification are values obtained by the following methods, respectively. First, a stable viscosity (ηa) is obtained after measuring for 2 minutes or more under the conditions of a temperature of 25 ° C. and a shear rate of 2s-1 using an E-type viscometer. Next, the viscosity (ηb) measured under the same conditions as above is obtained except that the shear rate is changed to 20s-1. Using the viscosity value obtained above, the TI value is calculated by the formula of TI value = ηa / ηb. When increasing the shear rate from 2s-1 to 20s-1, it may be increased in one step, or the shear rate may be increased in multiple steps within the above range, and the shear rate may be increased while appropriately acquiring the viscosity at the shear rate. You may let me.

The film thickness of the negative electrode active material layer is preferably 5 μm or more and 100 μm or less per one side. The lower limit of the film thickness of the negative electrode active material layer is more preferably 7 μm or more, still more preferably 10 μm or more. The upper limit of the film thickness of the negative electrode active material layer is more preferably 80 μm or less, and further preferably 60 μm or less. When this film thickness is 5 μm or more, no streaks or the like are generated when the negative electrode active material layer is applied, and the coatability is excellent. On the other hand, when this film thickness is 100 μm or less, a high energy density can be developed by reducing the cell volume. The film thickness of the negative electrode active material layer when the current collector has through holes or irregularities means the average value of the film thickness per side of the portion of the current collector that does not have through holes or irregularities.

The bulk density of the negative electrode active material layer is preferably 0.30 g / cm ³ or more and 1.8 g / cm ³ or less, more preferably 0.40 g / cm ³ or more and 1.5 g / cm ³ or less, and further preferably 0. .45g / cm ³ or more 1.3g / cm ³ or less. When the bulk density is 0.30 g / cm ³ or more, sufficient strength can be maintained and sufficient conductivity between the negative electrode active materials can be exhibited. Further, when the bulk density is 1.8 g / cm ³ or less, pores capable of sufficiently diffusing ions can be secured in the negative electrode active material layer.

[Compounds in the negative electrode active material layer]
The negative electrode active material layer according to the present embodiment is of the formula CH ₃ OX ¹ {in the formula, X ¹ is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. } Is preferably contained.
The compounds represented by the formula CH ₃ OX ¹ _{are more preferably CH 3} OLi and CH ₃ OCOOLi.
Here, the total content of the compound represented by the formula CH ₃ OX ^{1 in the negative electrode active material layer is 0.50 × 10-6} mol / g or more and 30.0 × per unit mass of the negative electrode active material layer. ^{It is preferably 10-6} mol / g or less, and ^{more preferably 0.70 × 10-6} mol / g or more and 20.0 × ^10-6 mol / g or less. When the total content of the compound is 0.50 × ^10-6 mol / g or more and 30.0 × ^10-6 mol / g or less, the diffusion of Li ions is not hindered and high input / output characteristics are exhibited. can do.

The negative electrode active material layer according to the present embodiment is further C ₂ H ₅ OX ² {in the formula, X ² is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. be. } Is preferably contained.
The _{compounds represented by C 2} H ₅ OX ² are more preferably C ₂ H ₅ OLi and C ₂ H ₅ OCOOLi.
Here, _{the total content of the compound represented by C 2} H ₅ OX ^{2 in the negative electrode active material layer is 0.10 × 10-6} mol / g or more and 20.0 per unit mass of the negative negative active material layer. preferably × at ¹⁰ -6 mol / g or less, and more preferably less 0.30 × ¹⁰ -6 mol / g or more 10.0 × ¹⁰ -6 mol / g. When the total content of the compound is 0.10 × ^10-6 mol / g or more and 20.0 × ^10-6 mol / g or less, the non-aqueous electrolyte solution does not come into contact with the negative electrode active material, and the non-aqueous electrolyte solution does not come into contact with the negative electrode active material. It is possible to suppress the generation of gas due to oxidative decomposition of the liquid.

As a method for containing the compound represented by the formula CH ₃ OX ¹ and / or the formula C ₂ H ₅ OX ^{2 according} to the present embodiment in the negative electrode active material layer, for example,
A method of mixing the compound with the negative electrode active material layer,
A method of adsorbing the compound on the negative electrode active material layer,
Examples thereof include a method of electrochemically precipitating the compound on the negative electrode active material layer.
Above all, in the negative electrode active material layer, a precursor capable of decomposing to produce these compounds is contained in the non-aqueous electrolyte solution, and the decomposition reaction of the precursor in the step of producing the power storage element is utilized. The method of depositing the compound on the surface is preferable.
As the precursor for forming the compound, it is preferable to use at least one organic solvent selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate.

Equation CH ₃ OX ¹ {In the equation, X ¹ is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. }, And the content per unit mass of the negative electrode material layer of the compound represented by} is D, and the formula C ₂ H ₅ OX ² {In the formula, X ² is − (O) _n Li or − (COO) _n Li. And n is 0 or 1. }, The D / E is preferably 1.10 or more and 15.00 or less, where E is the content per unit mass of the negative electrode material layer of the compound represented by. The D / E is more preferably 2.00 or more and 9.00 or less, and further preferably 2.50 or more and 8.00 or less. When the D / E is 1.10 or more, the diffusibility of Li ions at the negative electrode interface is improved, and high input / output characteristics can be maintained even in a low temperature environment. Further, when the D / E is 15.00 or less, the non-aqueous electrolytic solution is not oxidatively decomposed at the negative electrode interface to generate gas even in a high temperature environment. Therefore, when the D / E is 1.10 or more and 15.00 or less, it is possible to achieve both sufficient high temperature durability and high input / output characteristics in a low temperature environment.

The principle that sufficient high-temperature durability and high input / output characteristics in a low-temperature environment can be achieved by keeping the ratio of the Li compound content D and the Li compound content E contained in the negative electrode active material layer within a certain range is Although it is not clear, it is inferred as follows. The Li compound corresponding to the content D is a solid electrolyte membrane having high Li ion conductivity, and can improve the diffusibility of Li ions in the negative electrode active material layer during the charge / discharge reaction. On the other hand, the Li compound corresponding to the content E is a stable solid electrolyte membrane having high oxidation resistance, and can suppress oxidative decomposition at the negative electrode-electrolyte solution interface in a high temperature environment. By keeping the abundance ratio of these Li compounds in the negative electrode active material layer within a certain range, the diffusivity and oxidation resistance of Li ions at the negative electrode active material interface are improved, and under sufficient high temperature durability and low temperature environment. It is considered that high input / output characteristics can be achieved at the same time.

[Electrolytic solution]
The electrolytic solution of this embodiment is a non-aqueous electrolytic solution. That is, this electrolytic solution contains a non-aqueous solvent described later. The non-aqueous electrolyte solution preferably contains 0.5 mol / L or more of a lithium salt based on the total amount of the non-aqueous electrolyte solution. That is, the non-aqueous electrolyte solution preferably contains lithium ions as an electrolyte.

[Lithium salt]
The non-aqueous electrolyte solution of the present embodiment contains, as lithium salts, for example, (LiN (SO ₂ F) ₂ ), LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiN (SO _2). CF ₃ ) (SO ₂ C ₂ F ₅ ), LiN (SO ₂ CF ₃ ) (SO ₂ C ₂ F ₄ H), LiC (SO ₂ F) ₃ , LiC (SO ₂ CF ₃ ) ₃ , LiC (SO ₂₎ C ₂ F ₅ ) ₃ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiPF ₆ , LiBF _4, etc. can be used alone, or two or more of them may be mixed and used. Since it can exhibit high conductivity, the non-aqueous electrolyte solution preferably contains at least one selected from the group consisting of _{LiPF 6} , LiN (SO ₂ F) ₂ and LiBF _{4 , and LiPF 6} and / or LiBF ₄ And LiN (SO ₂ F) ₂ are more preferably contained.
The lithium salt concentration in the non-aqueous electrolyte solution is preferably 0.5 mol / L or more, more preferably 0.5 mol / L or more and 2.0 mol / L or less, based on the total amount of the non-aqueous electrolyte solution. .. When the lithium salt concentration is 0.5 mol / L or more, anions are sufficiently present, so that the capacity of the power storage element can be sufficiently increased. Further, when the lithium salt concentration is 2.0 mol / L or less, it is possible to prevent undissolved lithium salt from precipitating in the non-aqueous electrolytic solution and the viscosity of the electrolytic solution from becoming too high, resulting in a decrease in conductivity. It is preferable because it does not reduce the output characteristics.

The non-aqueous electrolyte solution of the present embodiment preferably contains _{LiN (SO 2} F) ₂ having a concentration of 0.3 mol / L or more and 1.5 mol / L or less based on the total amount of the non-aqueous electrolyte solution. The concentration of SO ₂ F) ₂ is more preferably 0.4 mol / L or more and 1.2 mol / L or less. When the LiN (SO ₂ F) ₂ concentration is 0.3 mol / L or more, the ionic conductivity of the electrolytic solution is increased, and an appropriate amount of an electrolyte film is deposited on the negative electrode interface, whereby the gas due to the decomposition of the electrolytic solution is released. It can be reduced. On the other hand, when this concentration is 1.5 mol / L or less, precipitation of the electrolyte salt does not occur during charging and discharging, and the viscosity of the electrolytic solution does not increase even after a long period of time.

[Non-aqueous solvent]
The non-aqueous electrolyte solution of the present embodiment preferably contains a cyclic carbonate as a non-aqueous solvent. The inclusion of the cyclic carbonate in the non-aqueous electrolyte solution is advantageous in that it dissolves a lithium salt having a desired concentration and that an appropriate amount of the lithium compound is deposited on the positive electrode active material layer. Examples of the cyclic carbonate include ethylene carbonate (EC), propylene carbonate, butylene carbonate, vinylene carbonate, fluoroethylene carbonate and the like.
The total content of the cyclic carbonate is preferably 15% by mass or more, more preferably 20% by mass or more, based on the total amount of the non-aqueous electrolyte solution. When the total content is 15% by mass or more, it is possible to dissolve a lithium salt having a desired concentration, and high lithium ion conductivity can be exhibited. Further, an appropriate amount of the lithium compound can be deposited on the positive electrode active material layer, and oxidative decomposition of the electrolytic solution can be suppressed.

The non-aqueous electrolyte solution of the present embodiment preferably contains dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC), which are chain carbonate compounds, as a non-aqueous solvent. The volume ratio (DMC / EMC) of the ethyl methyl carbonate to the dimethyl carbonate is preferably 0.5 or more and 8.0 or less, more preferably 0.8 or more and 6.0 or less, and 1.0 or more. It is more preferably 4.0 or less. When DMC / EMC is 0.5 or more, the viscosity of the electrolytic solution can be reduced and high lithium ion conductivity can be exhibited. When DMC / EMC is 8.0 or less, the melting point of the mixed solvent can be kept low, and high input / output characteristics can be exhibited even in a low temperature environment.

Further, the non-aqueous electrolyte solution of the present embodiment may contain other chain carbonate as a non-aqueous solvent. Examples of other chain carbonates include dialkyl carbonate compounds typified by diethyl carbonate, dipropyl carbonate, dibutyl carbonate and the like. Dialkyl carbonate compounds are typically unsubstituted.
The total content of the chain carbonate is preferably 30% by mass or more, more preferably 35% by mass or more, preferably 95% by mass or less, more preferably 90% by mass or less, based on the total amount of the non-aqueous electrolyte solution. be. When the content of the chain carbonate is 30% by mass or more, the viscosity of the electrolytic solution can be reduced and high lithium ion conductivity can be exhibited. When the total concentration is 95% by mass or less, the electrolytic solution can further contain the additives described later.

[Additive]
The non-aqueous electrolyte solution of the present embodiment may further contain an additive. The additive is not particularly limited, and for example, a sultone compound, cyclic phosphazene, acyclic fluorinated ether, fluorinated cyclic carbonate, cyclic carbonate, cyclic carboxylic acid ester, cyclic acid anhydride and the like can be used alone. It is possible, and two or more kinds may be mixed and used.

Examples of the sultone compound include sultone compounds represented by the following general formulas (5) to (7). These sultone compounds may be used alone or in combination of two or more.

｛式（５）中、Ｒ^１１〜Ｒ^１６は、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基、又は炭素数１〜１２のハロゲン化アルキル基を表し、互いに同一であっても異なっていてもよく；そしてｎは０〜３の整数である。｝

{In formula (5), R ^{11 to} R ¹⁶ represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkyl halide group having 1 to 12 carbon atoms, and they are different even if they are the same. May be; and n is an integer from 0 to 3. }

｛式（６）中、Ｒ^１１〜Ｒ^１４は、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基、又は炭素数１〜１２のハロゲン化アルキル基を表し、互いに同一であっても異なっていてもよく；そしてｎは０〜３の整数である。｝

{In formula (6), R ^{11 to} R ¹⁴ represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkyl halide group having 1 to 12 carbon atoms, and they are different even if they are the same. May be; and n is an integer from 0 to 3. }

｛式（７）中、Ｒ^１１〜Ｒ^１６は、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基、又は炭素数１〜１２のハロゲン化アルキル基を表し、互いに同一であっても異なっていてもよい。｝

{In formula (7), R ^{11 to} R ¹⁶ represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or an alkyl halide group having 1 to 12 carbon atoms, and they are different even if they are the same. May be. }

In the present embodiment, the sultone compound represented by the formula (5) is 1 from the viewpoint of less adverse effect on resistance and from the viewpoint of suppressing decomposition of the non-aqueous electrolyte solution at high temperature to suppress gas generation. , 3-Propane sultone, 2,4-butane sultone, 1,4-butane sultone, 1,3-butane sultone or 2,4-pentane sultone are preferable, and the sultone compound represented by the formula (6) is 1,3-. Propens sultone or 1,4-butene sultone is preferable, and as the sultone compound represented by the formula (7), 1,5,2,4-dioxadithiepan 2,2,4,4-tetraoxide is preferable. Other sultone compounds include methylenebis (benzenesulfonic acid), methylenebis (phenylmethanesulfonic acid), methylenebis (ethanesulfonic acid), methylenebis (2,4,6,trimethylbenzenesulfonic acid), and methylenebis (2-trifluoro). Methylbenzene sulfonic acid), and it is preferable to select at least one selected from these.

The total content of the sultone compound in the non-aqueous electrolyte solution of the non-aqueous lithium-type power storage element in the present embodiment is preferably 0.5% by mass or more and 15% by mass or less based on the total amount of the non-aqueous electrolyte solution. .. When the total content of the sultone compound in the non-aqueous electrolytic solution is 0.5% by mass or more, it is possible to suppress the decomposition of the electrolytic solution at a high temperature and suppress the gas generation. On the other hand, when the total content is 15% by mass or less, the decrease in the ionic conductivity of the electrolytic solution can be suppressed, and high input / output characteristics can be maintained. Further, the content of the sultone compound present in the non-aqueous electrolyte solution of the non-aqueous lithium-type power storage element is preferably 1% by mass or more and 10% by mass or less from the viewpoint of achieving both high input / output characteristics and durability. It is preferably 3% by mass or more and 8% by mass or less.

[Circular phosphazene]
Examples of the cyclic phosphazene include ethoxypentafluorocyclotriphosphazene, diethoxytetrafluorocyclotriphosphazene, phenoxypentafluorocyclotriphosphazene, and the like, and one or more selected from these is preferable.

The content of cyclic phosphazene in the non-aqueous electrolyte solution is preferably 0.5% by mass or more and 20% by mass or less based on the total amount of the non-aqueous electrolyte solution. When this value is 0.5% by weight or more, it is possible to suppress the decomposition of the electrolytic solution at a high temperature and suppress the gas generation. On the other hand, when this value is 20% by mass or less, the decrease in ionic conductivity of the electrolytic solution can be suppressed, and high input / output characteristics can be maintained. The content of cyclic phosphazene is more preferably 2% by mass or more and 15% by mass or less, and further preferably 4% by mass or more and 12% by mass or less.
These cyclic phosphazenes may be used alone or in combination of two or more.

[Acyclic fluorine-containing ether]
Examples of the acyclic fluorine-containing ether include HCF ₂ CF ₂ OCH ₂ CF ₂ CF ₂ H, CF ₃ CFHCF ₂ OCH ₂ CF ₂ CF ₂ H, HCF ₂ CF ₂ CH ₂ OCH ₂ CF ₂ CF ₂ H, CF ₃ CFHCF ₂ OCH ₂ CF ₂ CFHCF _{3 and the} like can be mentioned, and among them, HCF ₂ CF ₂ OCH ₂ CF ₂ CF ₂ H is preferable from the viewpoint of electrochemical stability.

The content of the acyclic fluorine-containing ether is preferably 0.5% by mass or more and 15% by mass or less, and more preferably 1% by mass or more and 10% by mass or less, based on the total amount of the non-aqueous electrolyte solution. When the content of the acyclic fluorine-containing ether is 0.5% by mass or more, the stability of the non-aqueous electrolyte solution against oxidative decomposition is enhanced, and a power storage element having high durability at high temperatures can be obtained. On the other hand, when the content of the acyclic fluorinated ether is 15% by mass or less, the solubility of the electrolyte salt can be kept good and the ionic conductivity of the non-aqueous electrolyte solution can be kept high, so that the concentration is high. It is possible to express input / output characteristics. The acyclic fluorine-containing ether may be used alone or in combination of two or more.

[Fluorine-containing cyclic carbonate]
The fluorine-containing cyclic carbonate is preferably used by selecting from fluoroethylene carbonate (FEC) and difluoroethylene carbonate (dFEC) from the viewpoint of compatibility with other non-aqueous solvents.
The content of the cyclic carbonate containing a fluorine atom is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 5% by mass or less, based on the total amount of the non-aqueous electrolyte solution. When the content of the cyclic carbonate containing a fluorine atom is 0.5% by mass or more, a high-quality film can be formed on the negative electrode, and by suppressing the reductive decomposition of the electrolytic solution on the negative electrode, the temperature is high. A power storage element with high durability can be obtained. On the other hand, when the content of the cyclic carbonate containing a fluorine atom is 10% by mass or less, the solubility of the electrolyte salt can be kept good and the ionic conductivity of the non-aqueous electrolyte solution can be kept high. It is possible to express a high degree of input / output characteristics. The above-mentioned cyclic carbonate containing a fluorine atom may be used alone or in combination of two or more.

[Cyclic carbonate]
For the cyclic carbonate, vinylene carbonate is preferable.
The content of the cyclic carbonate is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1% by mass or more and 5% by mass or less, based on the total amount of the non-aqueous electrolyte solution. When the content of the cyclic carbonate is 0.5% by mass or more, a high-quality film can be formed on the negative electrode, and by suppressing the reductive decomposition of the electrolytic solution on the negative electrode, the durability at high temperature can be improved. A high power storage element can be obtained. On the other hand, when the content of the cyclic carbonate is 10% by mass or less, the solubility of the electrolyte salt can be kept good and the ionic conductivity of the non-aqueous electrolyte solution can be maintained high, so that the input / output is highly high. It becomes possible to express the property.

[Cyclic carboxylic acid ester]
Examples of the cyclic carboxylic acid ester include gamma-butyrolactone, gamma-valerolactone, gamma caprolactone, and epsilon caprolactone, and it is preferable to use one or more selected from these. Of these, gamma-butyrolactone is particularly preferable from the viewpoint of improving battery characteristics resulting from an improvement in the degree of lithium ion dissociation.
The content of the cyclic carboxylic acid ester is preferably 0.5% by mass or more and 15% by mass or less, and more preferably 1% by mass or more and 5% by mass or less, based on the total amount of the non-aqueous electrolyte solution. When the content of cyclic acid anhydride is 0.5% by mass or more, a high-quality film can be formed on the negative electrode, and by suppressing the reductive decomposition of the electrolytic solution on the negative electrode, durability at high temperature is achieved. A high power storage element can be obtained. On the other hand, when the content of the cyclic carboxylic acid ester is 15% by mass or less, the solubility of the electrolyte salt can be kept good and the ionic conductivity of the non-aqueous electrolyte solution can be maintained high, so that the content is high. It is possible to express output characteristics. The above cyclic carboxylic acid ester may be used alone or in combination of two or more.

[Cyclic acid anhydride]
As the cyclic acid anhydride, one or more selected from succinic anhydride, maleic anhydride, citraconic anhydride, and itaconic anhydride are preferable. Among them, it is preferable to select from succinic anhydride and maleic anhydride because the production cost of the electrolytic solution can be suppressed due to the availability in the industry and the electrolyte is easily dissolved in the non-aqueous electrolytic solution.
The content of the cyclic acid anhydride is preferably 0.5% by mass or more and 15% by mass or less, and more preferably 1% by mass or more and 10% by mass or less, based on the total amount of the non-aqueous electrolyte solution. When the content of the cyclic acid anhydride is 0.5% by mass or more, a high-quality film can be formed on the negative electrode, and by suppressing the reductive decomposition of the electrolytic solution on the negative electrode, the durability at high temperature can be improved. A high power storage element can be obtained. On the other hand, when the content of the cyclic acid anhydride is 15% by mass or less, the solubility of the electrolyte salt can be kept good, and the ionic conductivity of the non-aqueous electrolyte solution can be maintained high, and therefore a high degree of input / output can be maintained. It becomes possible to express the property. The above cyclic acid anhydride may be used alone or in combination of two or more.

[Separator]
The positive electrode precursor and the negative electrode are laminated or wound via a separator to form an electrode laminate or an electrode wound body having the positive electrode precursor, the negative electrode and the separator.
As the separator, a polyethylene microporous film or polypropylene microporous film used in a lithium ion secondary battery, a cellulose non-woven paper used in an electric double layer capacitor, or the like can be used. A film made of organic or inorganic fine particles may be laminated on one side or both sides of these separators. Further, organic or inorganic fine particles may be contained inside the separator.
The thickness of the separator is preferably 5 μm or more and 35 μm or less. A thickness of 5 μm or more is preferable because self-discharge due to internal microshorts tends to be small. On the other hand, when the thickness is 35 μm or less, the input / output characteristics of the non-aqueous lithium-type power storage element tend to be improved, which is preferable.
The film made of organic or inorganic fine particles is preferably 1 μm or more and 10 μm or less. A thickness of 1 μm or more is preferable because self-discharge due to internal microshorts tends to be small. On the other hand, a thickness of 10 μm or less is preferable because the input / output characteristics of the non-aqueous lithium-type power storage element tend to be improved.

[Non-aqueous lithium-type power storage element]
The non-aqueous lithium-type power storage element of the present embodiment is configured such that an electrode laminate or an electrode winding body, which will be described later, is housed in the exterior body together with the non-aqueous electrolyte solution.

[assembly]
The electrode laminate obtained in the cell assembly step is a laminate obtained by laminating a positive electrode precursor and a negative electrode cut into a single-wafer shape via a separator, and connecting a positive electrode terminal and a negative electrode terminal to the laminate. Further, the electrode winding body is formed by connecting a positive electrode terminal and a negative electrode terminal to a winding body formed by winding a positive electrode precursor and a negative electrode via a separator. The shape of the electrode winding body may be cylindrical or flat.
The method of connecting the positive electrode terminal and the negative electrode terminal is not particularly limited, but a method such as resistance welding or ultrasonic welding is used.

[Exterior body]
As the exterior body, a metal can, a laminated packaging material, or the like can be used.
The metal can is preferably made of aluminum.
As the laminated packaging material, a film obtained by laminating a metal foil and a resin film is preferable, and a three-layer structure composed of an outer layer resin film / metal foil / interior resin film is exemplified. The outer layer resin film is for preventing the metal foil from being damaged by contact or the like, and a resin such as nylon or polyester can be preferably used. The metal foil is for preventing the permeation of moisture and gas, and foils such as copper, aluminum, and stainless steel can be preferably used. Further, the interior resin film is for protecting the metal foil from the non-aqueous electrolytic solution stored inside and for melting and sealing the exterior body at the time of heat sealing, and polyolefins, acid-modified polyolefins and the like can be preferably used.

[Storage in the exterior]
It is preferable that the dried electrode laminate or electrode wound body is housed in an exterior body typified by a metal can or a laminate packaging material, and sealed with only one opening left. The sealing method of the outer body is not particularly limited, but when a laminated packaging material is used, a method such as heat sealing or impulse sealing is used.

[Dry]
It is preferable that the electrode laminate or the electrode wound body housed in the outer body is dried to remove the residual solvent. The drying method is not limited, but it is dried by vacuum drying or the like. The residual solvent is preferably 1.5% by mass or less per mass of the positive electrode active material layer or the negative electrode active material layer. If the residual solvent is more than 1.5% by mass, the solvent remains in the system and the self-discharge characteristics or the cycle characteristics are deteriorated, which is not preferable.

[Liquid injection, impregnation, sealing process]
After the assembly process is completed, the non-aqueous electrolyte solution is injected into the electrode laminate or electrode winding body housed in the exterior body. After the completion of the liquid injection step, it is desirable to further impregnate and sufficiently immerse the positive electrode, the negative electrode, and the separator with a non-aqueous electrolyte solution. When the non-aqueous electrolyte solution is not immersed in at least a part of the positive electrode, the negative electrode, and the separator, the doping proceeds unevenly in the lithium doping step described later, so that the resistance of the obtained non-aqueous lithium storage element becomes high. It rises or becomes less durable. The impregnation method is not particularly limited, but for example, the electrode laminate or electrode winding body after injection is installed in a decompression chamber with the outer body open, and the inside of the chamber is used with a vacuum pump. A method of reducing the pressure and returning the pressure to atmospheric pressure can be used. After the impregnation step is completed, the electrode laminate or electrode wound body with the outer body open is sealed while reducing the pressure.

[Lithium dope process]
In the lithium doping step, preferably, a voltage is applied between the positive electrode precursor and the negative electrode to decompose the lithium compound described above, thereby decomposing the lithium compound in the positive electrode precursor and lithium ions. Lithium ions are pre-doped into the negative electrode active material layer by releasing lithium ions and reducing lithium ions at the negative electrode.
_{In this lithium doping step, gas such as CO 2} is generated due to oxidative decomposition of the lithium compound in the positive electrode precursor. Therefore, when applying a voltage, it is preferable to take measures to release the generated gas to the outside of the exterior body. As this means, for example, a method of applying a voltage with a part of the exterior body opened; a state in which an appropriate gas release means such as a gas vent valve or a gas permeable film is previously installed in the part of the exterior body. A method of applying a voltage with the above;

[Aging process]
After the lithium doping step is completed, it is preferable to age the electrode laminate or the electrode wound body. In the aging step, the solvent in the non-aqueous electrolyte solution is decomposed at the negative electrode, and a lithium ion permeable solid polymer film is formed on the surface of the negative electrode.
The aging method is not particularly limited, and for example, a method of reacting a solvent in a non-aqueous electrolyte solution in a high temperature environment can be used.

<Additional charge>
After aging, it is preferable to additionally charge the electrode laminate or the electrode winding body. Due to the additional charging, the electrolyte in the non-aqueous electrolyte solution is decomposed at the positive electrode to release the fluoride ion source, which adheres to the surface of the separator and produces a particulate substance. As a result, the permeability and liquid retention of the electrolytic solution to the separator are improved, so that a low-resistance non-aqueous lithium-type power storage element can be obtained, and the mechanical and electrochemical durability of the separator at high temperatures can be obtained. By increasing the amount of water, it is possible to obtain a non-aqueous lithium-type power storage element having excellent durability under high temperature storage.

[Degassing process]
After the aging step is completed, it is preferable to further degas to surely remove the gas remaining in the non-aqueous electrolyte solution, the positive electrode, and the negative electrode. In a state where gas remains in at least a part of the non-aqueous electrolyte solution, the positive electrode, and the negative electrode, ion conduction is inhibited, so that the resistance of the obtained non-aqueous lithium storage element increases.
The degassing method is not particularly limited, but for example, the electrode laminate or the electrode winding body is installed in the decompression chamber with the exterior body open, and the inside of the chamber is depressurized by using a vacuum pump. A method or the like can be used.

[Capacitance]
In the present specification, the capacitance F (F) is a value obtained by the following method:
First, in a constant temperature bath in which the cell corresponding to the non-aqueous lithium-type power storage element is set to 25 ° C., constant current charging is performed until the current value of 20C reaches 3.8V, and then a constant voltage of 3.8V is applied. The constant voltage charging to be applied is performed for a total of 30 minutes. After that, let Q be the capacitance when constant current discharge is performed with a current value of 2C up to 2.2V. It means a value calculated by F = Q / (3.8-2.2) using the Q obtained here.

[Electric energy]
In the present specification, the electric energy E (Wh) is a value obtained by the following method:
It refers to a value calculated by F × (3.8-2.2) / 2/3600 using the capacitance F (F) calculated by the method described above.

[volume]
The volume of the non-aqueous lithium-type power storage element is not particularly specified, but the region in which the positive electrode active material layer and the negative electrode active material layer are stacked in the electrode laminate or the electrode wound body is housed by the exterior body. Refers to the volume of a part.

For example, in the case of an electrode laminate or an electrode wound body housed by a laminate film, a region of the electrode laminate or the electrode wound body in which the positive electrode active material layer and the negative electrode active material layer exist is cup-formed. Although housed in a laminated film, the volume (V1) of this non-aqueous lithium-type power storage element includes the outer dimension length (l1), outer dimension width (w1), and laminate film of this cup-molded portion. It is calculated by V1 = l1 × w1 × t1 according to the thickness (t1) of the non-aqueous lithium-type power storage element.

In the case of an electrode laminate or an electrode wound body housed in a square metal can, the volume of the non-aqueous lithium power storage element is simply the volume of the outer dimension of the metal can. That is, the volume (V2) of this non-aqueous lithium-type power storage element depends on the outer dimension length (l2), outer dimension width (w2), and outer dimension thickness (t2) of the square metal can, and V2 = l2 × w2. It is calculated by × t2.

Further, even in the case of the electrode wound body housed in the cylindrical metal can, the volume of the non-aqueous lithium power storage element is the volume of the outer dimension of the metal can. That is, the volume (V3) of this non-aqueous lithium-type power storage element is V3 = 3.14 × r × depending on the outer dimension radius (r) and outer dimension length (l3) of the bottom surface or the upper surface of the cylindrical metal can. It is calculated by r × l3.

[Energy density]
In the present specification, the energy density is a value obtained by the formula of E / Vi (Wh / L) using the amount of electricity E and the volume Vi (i = 1, 2, 3).

[Room temperature internal resistance]
In the present specification, the room temperature internal resistance Ra (Ω) is a value obtained by the following method:
First, the cell corresponding to the non-aqueous lithium-type power storage element is charged with a constant current at a current value of 20C until it reaches 3.8V in a constant temperature bath set at 25 ° C., and then a constant voltage of 3.8V is applied. Perform constant voltage charging for a total of 30 minutes. Subsequently, a constant current discharge is performed up to 2.2 V with a current value of 20 C to obtain a discharge curve (time-voltage). In this discharge curve, when the voltage at the discharge time = 0 second obtained by extrapolating from the voltage values at the time points of the discharge time of 2 seconds and 4 seconds is Eo, the voltage drop ΔE = 3.8- It is a value calculated by Eo and Ra = ΔE / (20C (current value A)).

[Low temperature internal resistance]
As used herein, the low temperature internal resistance Rc is a value obtained by the following method:
First, the cell corresponding to the non-aqueous lithium-type power storage element is left in a constant temperature bath set at −10 ° C. for 2 hours. After that, while keeping the constant temperature bath at -10 ° C, constant current charging is performed at a current value of 1.0 C until it reaches 3.8 V, and then constant voltage charging at which a constant voltage of 3.8 V is applied is performed for a total of 2 Do time. Subsequently, a constant current discharge is performed up to 2.2 V with a current value of 50 C to obtain a discharge curve (time-voltage). In this discharge curve, when the voltage at the discharge time = 0 second obtained by extrapolating from the voltage values at the time points of the discharge time of 2 seconds and 4 seconds is Eo, the voltage drop ΔE = 3.8- It is a value calculated by Eo and Rb = ΔE / (10C (current value A)).

[High temperature storage test]
In the present specification, the amount of gas generated during the high temperature storage test and the rate of increase in internal resistance at room temperature after the high temperature storage test are measured by the following methods:
First, the cell corresponding to the non-aqueous lithium-type power storage element is charged with a constant current in a constant temperature bath set at 25 ° C. until it reaches 4.0 V with a current value of 100 C, and then a constant voltage of 4.0 V is applied. Perform constant voltage charging for 10 minutes. After that, the cell is stored in the environment of 60 ° C., taken out from the environment of 60 ° C. every two weeks, the cell voltage is charged to 4.0 V in the above-mentioned charging step, and then the cell is stored in the environment of 60 ° C. again. .. This step is repeated, and the cell volume Va before the start of storage and the cell volume Vb 2 months after the storage test are measured by the Archimedes method. Let Vb-V be the amount of gas generated when stored for 2 months at a cell voltage of 4.0 V and an environmental temperature of 60 ° C.
When the resistance value obtained by using the same measurement method as the normal temperature internal resistance for the cell after the high temperature storage test is the normal temperature internal resistance Rc after the high temperature storage test, the normal temperature internal resistance before the start of the high temperature storage test The rate of increase in internal resistance at room temperature after the high-temperature storage test for Ra is calculated by Rc / Ra.

[Nail piercing test]
In the present specification, the nail piercing test is performed by the following method:
First, the cell corresponding to the non-aqueous lithium-type power storage element is charged with a constant current in a constant temperature bath set at 25 ° C. until it reaches 4.0 V with a current value of 100 C, and then a constant voltage of 4.0 V is applied. Perform constant voltage charging for 10 minutes.
A nail piercing test is performed on the power storage element whose voltage has been adjusted to 4.0 V in the above step under the following conditions.
Testing machine: Shimadzu Autograph AG-X
Nail: φ2.5mm-SUS304
Environmental temperature: 25 ° C
Evaluation method: After fixing the power storage element horizontally and attaching a thermocouple to the positive electrode terminal, negative electrode terminal, and the central surface of the exterior body of the power storage element, nail the center of the power storage element until it penetrates at a speed of 20 mm / sec. Stab. Observe the heat generation temperature of each part during the test and the behavior of the power storage element.
In the present specification, the heat generation temperature ΔT of the nail piercing test is defined as
From the maximum ultimate temperature of the positive electrode terminal, the maximum ultimate temperature of the negative electrode terminal, and the maximum ultimate temperature of the central surface of the exterior body at the time of the test, the one with the highest ultimate temperature is T1 and the environmental temperature is T2. = The value obtained by T1-T2.

In addition, the behavior of the power storage element during the nail piercing test is classified into the following four states.
Ignition: Non-aqueous lithium storage element burned,
Rupture: A state in which part or all of the exterior of a non-aqueous lithium storage element is damaged and part or all of the electrode laminate protrudes from the exterior.
Cleavage: A state in which a part of the exterior body of the non-aqueous lithium storage element is damaged and the electrode laminate remains inside the exterior body (the non-aqueous electrolyte solution may flow out from the damaged part of the exterior body). ,
No change: No damage to the exterior (the exterior may expand due to gas generation),
Is defined as.

In the non-aqueous lithium-type power storage element of the present embodiment, the heat generation temperature ΔT in the nail piercing test is preferably less than 80 ° C, more preferably less than 75 ° C, and even more preferably less than 70 ° C. Since ΔT is less than 80 ° C., even if the non-aqueous lithium storage element is damaged by an external impact, the thermal runaway reaction at the electrode-electrolyte solution interface inside the battery will not cause bursting or ignition. Therefore, it is possible to ensure sufficient safety.

The non-aqueous lithium-type power storage element of the present embodiment houses an initial room temperature internal resistance at a cell voltage of 4 V, Ra (Ω), a capacitance of F (F), a power amount of E (Wh), and an electrode laminate. When the volume of the exterior body is V (L) and the internal resistance at an ambient temperature of −10 ° C. is Rb, the following requirements (a), (b) and (c) are:
(A) The product Ra / F of Ra and F is 0.3 or more and 3.0 or less.
(B) E / V is 15 or more and 50 or less.
(C) Rb / Ra is 10 or less.
Is preferably satisfied at the same time.

Regarding (a), Ra and F are preferably 3.0 or less, more preferably 2.6 or less, and further, from the viewpoint of developing sufficient charge capacity and discharge capacity with respect to a large current. It is preferably 2.4 or less. When Ra and F are not more than the above upper limit values, a non-aqueous lithium-type power storage element having excellent input / output characteristics can be obtained. Therefore, by combining a power storage system using a non-aqueous lithium-type power storage element with, for example, a high-efficiency engine, it is possible to sufficiently withstand a high load applied to the non-aqueous lithium-type power storage element.

Regarding (b), the E / V is preferably 15 or more, more preferably 18 or more, and further preferably 20 or more, from the viewpoint of developing a sufficient charge capacity and discharge capacity. When the E / V is equal to or higher than the above lower limit value, a power storage element having an excellent volumetric energy density can be obtained. Therefore, when a power storage system using a power storage element is used in combination with an automobile engine, for example, the power storage system can be installed in a limited narrow space inside the car.

Regarding (c), Rb / Ra is preferably 10 or less, more preferably 8 or less, and further preferably 8 or less, from the viewpoint of developing sufficient charge capacity and discharge capacity even in a low temperature environment of −10 ° C. It is preferably 6 or less. When Rb / Ra is not more than the above upper limit value, a power storage element having excellent output characteristics can be obtained even in a low temperature environment. Therefore, when the engine of an automobile, a motorcycle, or the like is started in a low temperature environment, it is possible to obtain a power storage element that gives sufficient electric power to drive the motor.

The non-aqueous lithium-type power storage element of the present embodiment stores the initial room temperature internal resistance at a cell voltage of 4 V at Ra (Ω), a capacitance of F (F), a cell voltage of 4 V, and an ambient temperature of 60 ° C. for 2 months. When the internal resistance at 25 ° C. is Rc (Ω), the following requirements (d) and (e) are:
(D) Rc / Ra is 0.3 or more and 3.0 or less.
(E) The amount of gas generated when stored for 2 months at a cell voltage of 4 V and an environmental temperature of 60 ° C. is 30 × 10 ^-3 cc / F or less at 25 ° C.
Is preferably satisfied at the same time.

Regarding (d), Rc / Ra is preferably 3.0 or less from the viewpoint of developing sufficient charge capacity and discharge capacity for a large current when exposed to a high temperature environment for a long time. , More preferably 2.0 or less, still more preferably 1.5 or less. When Rc / Ra is not more than the above upper limit value, stable and excellent output characteristics can be obtained for a long period of time, which leads to a long life of the device.

Regarding (e), the amount of gas generated when stored at a cell voltage of 4.0 V and an environmental temperature of 60 ° C. for 2 months is such that the amount of gas generated is 25 ° C. from the viewpoint that the characteristics of the device are not deteriorated by the generated gas. The measured value ^{is preferably 30 × 10 -3} cc / F or less, more preferably 20 × 10 ^-3 cc / F or less, and further preferably 15 × 10 ^-3 cc / F or less. When the amount of gas generated under the above conditions is equal to or less than the above upper limit value, there is no possibility that the cell will expand due to gas generation even when the device is exposed to a high temperature for a long period of time. Therefore, a power storage element having sufficient safety and durability can be obtained.

A storage module can be manufactured by connecting a plurality of non-aqueous lithium-type power storage elements according to the present embodiment in series or in parallel. Further, the non-aqueous lithium type power storage element and the power storage module can be used in a power regeneration system, a power load leveling system, an uninterruptible power supply system, a contactless power supply system, an energy harvest system, a power storage system, and the like.
The non-aqueous lithium-type power storage element according to the present embodiment has high output and high capacity, and can maintain its characteristics in a wide range of environmental temperatures. Therefore, power regeneration systems for hybrid drive systems of automobiles that require high load charge / discharge cycle characteristics, natural power generation such as solar power generation or wind power generation, power load leveling systems for microgrids, etc., no power outages in factory production equipment, etc. It can be suitably used for a power supply system, a non-contact power supply system for leveling voltage fluctuations such as microwave power transmission or electric field resonance and storing energy, and an energy harvest system for using power generated by vibration power generation. ..

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

(Example 1)

<Crushing lithium carbonate>
200 g of lithium carbonate having an average particle size of 53 μm is cooled to -196 ° C. with liquid nitrogen using a crusher (liquid nitrogen bead mill LNM) manufactured by IMEX, and then using dry ice beads at a peripheral speed of 10.0 m / s. Was crushed for 9 minutes. The charged lithium carbonate particle size was determined by measuring the average particle size of the lithium carbonate obtained by preventing thermal denaturation at -196 ° C. and brittle fracture, and found to be 1.5 μm.

<Preparation of positive electrode active material>
[Preparation of positive electrode active material A]
The crushed coconut shell carbide was carbonized in nitrogen at 500 ° C. for 3 hours in a small carbonization furnace to obtain carbonized material. The obtained carbide was put into an activation furnace, and 1 kg / h of steam was introduced into the activation furnace in a state of being heated by the preheating furnace, and the temperature was raised to 900 ° C. over 8 hours for activation. The activated carbon was taken out and cooled in a nitrogen atmosphere to obtain activated activated carbon. The obtained activated carbon was washed with water for 10 hours and then drained. Then, after drying for 10 hours in an electric dryer maintained at 115 ° C., activated carbon A was obtained by pulverizing with a ball mill for 1 hour.
The average particle size of this activated carbon A was 4.2 μm as a result of measuring the average particle size using a laser diffraction type particle size distribution measuring device (SALD-2000J) manufactured by Shimadzu Corporation. In addition, the pore distribution was measured using a pore distribution measuring device (AUTOSORB-1 AS-1-MP) manufactured by Yuasa Ionics. As a result, the BET specific surface area was 2360 m ² / g, the mesopore amount (V1) was 0.52 cc / g, the micropore amount (V2) was 0.88 cc / g, and V1 / V2 = 0.59.

[Preparation of positive electrode active material B]
The phenol resin was carbonized in a firing furnace at 600 ° C. for 2 hours in a nitrogen atmosphere, then pulverized with a ball mill and classified to obtain a carbide having an average particle size of 7 μm. This carbide and KOH were mixed at a mass ratio of 1: 5, and activated by heating in a firing furnace at 800 ° C. for 1 hour in a nitrogen atmosphere. Then, the mixture was stirred and washed for 1 hour in dilute hydrochloric acid adjusted to a concentration of 2 mol / L. Further, the mixture was boiled and washed with distilled water until it became stable at pH 5 to 6, and then dried to obtain activated carbon B.
The pore distribution of this activated carbon B was measured using a pore distribution measuring device (AUTOSORB-1 AS-1-MP) manufactured by Yuasa Ionics. As a result, the BET specific surface area was 3627 m ² / g, the mesopore amount (V1) was 1.50 cc / g, the micropore amount (V2) was 2.28 cc / g, and V1 / V2 = 0.66.

<Manufacturing of positive electrode precursor A>
The activated carbon A obtained above was used as the positive electrode active material to produce a positive electrode precursor.
Activated carbon A is 57.5 parts by mass, lithium carbonate with an average particle size of 1.5 μm as a lithium compound is 30.0 parts by mass, KB (Ketchen Black) is 3.0 parts by mass, and PVP (polypolypyrrolidone) is 1.5 parts. Mixing 8.0 parts by mass and PVDF (polyvinylidene fluoride) and NMP (N-methylpyrrolidone), and using a thin film swirling high-speed mixer fill mix manufactured by PRIMIX, a peripheral speed of 17 m / A coating liquid was obtained by dispersing under the condition of s. The viscosity (ηb) and TI value of the obtained coating liquid were measured using an E-type viscometer TVE-35H manufactured by Toki Sangyo Co., Ltd. As a result, the viscosity (ηb) was 2,700 mPa · s, and the TI value was 3.5. In addition, the degree of dispersion of the obtained coating liquid was measured using a grain gauge manufactured by Yoshimitsu Seiki Co., Ltd. As a result, the particle size was 35 μm. The above coating liquid is applied to one or both sides of an aluminum foil having a thickness of 15 μm using a die coater manufactured by Toray Engineering Co., Ltd. at a coating speed of 1 m / s, dried at a drying temperature of 100 ° C., and a positive electrode precursor. Got The obtained positive electrode precursor was pressed using a roll press machine under the conditions of a pressure of 4 kN / cm and a surface temperature of the press portion of 25 ° C. The average thickness of the positive electrode active material layer of the positive electrode precursor obtained above was measured at any 10 locations of the positive electrode precursor using a film thickness meter Linear Gauge Sensor GS-551 manufactured by Ono Keiki Co., Ltd. It was calculated by subtracting the thickness of the aluminum foil from the value. As a result, the film thickness of the positive electrode active material layer was 60 μm per side.

<Manufacturing of positive electrode precursor B>
A positive electrode precursor B was obtained according to the same method as in the production of the positive electrode precursor A except that the activated carbon B obtained above was used as the positive electrode active material.

Hereinafter, the single-sided positive electrode precursor and the double-sided positive electrode precursor using the activated carbon A will be referred to as a single-sided positive electrode precursor A and a double-sided positive electrode precursor A (collectively, “positive electrode precursor A”). Single-sided positive electrode precursor and double-sided positive electrode precursor using activated carbon B are referred to as single-sided positive electrode precursor B and double-sided positive electrode precursor B (collectively, "positive electrode precursor B").

<Preparation of negative electrode active material>
[Preparation of active substance A]
Made of stainless steel containing 150 g of commercially available coconut shell activated carbon with an average particle size of 3.0 μm and a BET specific surface area of 1,780 m ² / g in a stainless steel mesh cage and 270 g of coal-based pitch (softening point: 50 ° C.). The composite carbon material A was obtained by placing it on a bat, placing both of them in an electric furnace (effective dimensions in the furnace 300 mm × 300 mm × 300 mm), and conducting a thermal reaction. This heat treatment was carried out in a nitrogen atmosphere, the temperature was raised to 600 ° C. in 8 hours, and the temperature was maintained at the same temperature for 4 hours. Subsequently, after cooling to 60 ° C. by natural cooling, the composite carbon material A was taken out from the furnace.
With respect to the obtained composite carbon material A, the average particle size and the BET specific surface area were measured by the same method as described above. As a result, the average particle size was 3.2 μm and the BET specific surface area was 262 m ² / g. The mass ratio of the carboniferous material derived from the carboniferous pitch to the activated carbon was 78%.

<Manufacturing of negative electrode A>
Next, a negative electrode was manufactured using the composite carbon material A as the negative electrode active material.
85 parts by mass of composite carbon material A, 10 parts by mass of acetylene black, 5 parts by mass of PVdF (polyvinylidene fluoride), and NMP (N-methylpyrrolidone) are mixed and mixed with a thin film swirl type high speed manufactured by PRIMIX. Using a mixer fill mix, a coating liquid was obtained by dispersing under the condition of a peripheral speed of 15 m / s. The viscosity (ηb) and TI value of the obtained coating liquid were measured using an E-type viscometer TVE-35H manufactured by Toki Sangyo Co., Ltd. As a result, the viscosity (ηb) was 2,789 mPa · s, and the TI value was 4.3. The above coating liquid was applied to both sides of an electrolytic copper foil having a thickness of 10 μm and having no through holes using a die coater manufactured by Toray Engineering Co., Ltd. at a coating speed of 1 m / s, and dried at a drying temperature of 85 ° C. A double-sided negative electrode A was obtained. The obtained negative electrode A was pressed using a roll press machine under the conditions of a pressure of 4 kN / cm and a surface temperature of the press portion of 25 ° C. The film thickness of the negative electrode active material layer of the negative electrode A obtained above was measured from the average value of the thickness measured at any 10 points of the negative electrode A using a film thickness meter Linear Gauge Sensor GS-551 manufactured by Ono Keiki Co., Ltd. , Calculated by subtracting the thickness of the copper foil. As a result, the film thickness of the negative electrode active material layer of the negative electrode A was 40 μm per side.

[Preparation of active material B]
Instead of the composite carbon material A, artificial graphite having an average particle diameter of 4.9 μm was used as a base material, the amount of coal-based pitch used was 50 g, and the heat treatment temperature was 1000 ° C. The composite carbon material B was produced and evaluated. As a result, the BET specific surface area of the composite carbon material B was 6.1 m ² / g. The mass ratio of the carbonaceous material derived from coal-based pitch to artificial graphite was 2%.

<Manufacturing of negative electrode B>
A negative electrode was manufactured using the composite carbon material B obtained above as a negative electrode active material.
80 parts by mass of composite carbon material B, 8 parts by mass of acetylene black, 12 parts by mass of PVdF (polyvinylidene fluoride), and NMP (N-methylpyrrolidone) are mixed and mixed with a thin film swirl type high speed manufactured by PRIMIX. Using a mixer fill mix, a coating liquid was obtained by dispersing under the condition of a peripheral speed of 15 m / s. The viscosity (ηb) and TI value of the obtained coating liquid were measured using an E-type viscometer TVE-35H manufactured by Toki Sangyo Co., Ltd. As a result, the viscosity (ηb) was 2,798 mPa · s, and the TI value was 2.7. The above coating liquid was applied to both sides of an electrolytic copper foil having a thickness of 10 μm and having no through holes using a die coater manufactured by Toray Engineering Co., Ltd. at a coating speed of 1 m / s, and dried at a drying temperature of 85 ° C. A double-sided negative electrode B was obtained. The obtained negative electrode B was pressed using a roll press machine under the conditions of a pressure of 4 kN / cm and a surface temperature of the pressed portion of 25 ° C. The film thickness of the negative electrode active material layer of the negative electrode B obtained above was measured from the average value of the thickness measured at any 10 locations of the negative electrode B using a film thickness meter Linear Gauge Sensor GS-551 manufactured by Ono Keiki Co., Ltd. , Calculated by subtracting the thickness of the copper foil. As a result, the film thickness of the negative electrode active material layer was 25 μm per one side.

<Preparation of electrolyte>
As the organic solvent, a mixed solvent of ethylene carbonate (EC): dimethyl carbonate (DMC): methyl ethyl carbonate (EMC) = 33.0: 26.0: 41.0 (volume ratio) was used with respect to the total electrolytic solution. The concentration ratio of LiN (SO ₂ F) ₂ and LiPF ₆ is 50:50 (molar ratio), and _{the sum of the concentrations of LiN (SO 2} F) ₂ and LiPF ₆ is 1.2 mol / L, respectively. The solution obtained by dissolving the electrolyte salt of No. 1 was used as a non-aqueous electrolyte solution.
_{The concentrations of LiN (SO 2} F) ₂ and LiPF ₆ in the electrolytic solution prepared here were 0.6 mol / L and 0.6 mol / L, respectively.

<Assembly of power storage element>
The obtained double-sided negative electrode A and double-sided positive electrode precursor A were cut into ^{10 cm × 10 cm (100 cm 2).} A single-sided positive electrode precursor A is used for the uppermost surface and the lowermost surface, and 21 double-sided negative electrode A and 20 double-sided positive electrode precursors A are used. It was sandwiched and laminated. Then, the negative electrode terminal and the positive electrode terminal were connected to the negative electrode and the positive electrode precursor by ultrasonic welding, respectively, to form an electrode laminate. This electrode laminate was vacuum dried at 80 ° C. and 50 Pa for 60 hr. This electrode laminate is inserted into an exterior body made of an aluminum laminate packaging material in a dry environment with a dew point of −45 ° C. Heat sealed. A non-aqueous lithium-type power storage element was assembled by injecting a non-aqueous electrolyte solution into the exterior body and sealing the exterior body.

<Liquid injection, impregnation, sealing process of power storage element>
Approximately 80 g of the non-aqueous electrolyte solution was injected into the electrode laminate housed in the aluminum laminate packaging material in a dry air environment with a dew point of −40 ° C. or lower under atmospheric pressure at a temperature of 25 ° C. Subsequently, the non-aqueous lithium-type power storage element was placed in the decompression chamber, the pressure was reduced from normal pressure to −87 kPa, the pressure was returned to atmospheric pressure, and the mixture was allowed to stand for 5 minutes. Then, the pressure was reduced from normal pressure to −87 kPa, the process of returning to atmospheric pressure was repeated 4 times, and then the mixture was allowed to stand for 15 minutes. Further, the pressure was reduced from normal pressure to −91 kPa, and then returned to atmospheric pressure. Similarly, the steps of depressurizing and returning to atmospheric pressure were repeated 7 times in total. (Reduced pressure to -95, 96, 97, 81, 97, 97, 97 kPa, respectively). Through the above steps, the electrode laminate was impregnated with the non-aqueous electrolyte solution.
Then, the non-aqueous lithium-type power storage element was placed in a vacuum sealing machine, and the aluminum laminate packaging material was sealed by sealing at 180 ° C. for 10 seconds at a pressure of 0.1 MPa with the pressure reduced to −95 kPa.

<Lithium dope process>
For the obtained non-aqueous lithium-type power storage element, a charging / discharging device (TOSCAT-3100U) manufactured by Toyo Systems Co., Ltd. is used, and the voltage is fixed until the voltage reaches 4.5 V at a current value of 0.2 A in an environment of 25 ° C. After the current charge, the initial charge was carried out by the method of continuing the 4.5 V constant voltage charge for 30 hours, and the negative electrode was lithium-doped.

<Aging process>
A non-aqueous lithium-type power storage element after lithium doping is discharged at 0.7 A at a constant current until it reaches a voltage of 3.0 V, and then charged at a constant current of 4.0 V at 1 A. Was adjusted to 4.0V. Subsequently, the non-aqueous lithium-type power storage element was stored in a constant temperature bath at 60 ° C. for 48 hours.

<Degassing process>
A part of the aluminum laminate packaging material was opened in a dry air environment at a temperature of 25 ° C. and a dew point of −40 ° C. for the aged non-aqueous lithium-type power storage element. Subsequently, the non-aqueous lithium-type power storage element was placed in the decompression chamber, and the pressure was reduced from atmospheric pressure to −80 kPa over 3 minutes using a diaphragm pump (N816.3KT.45.18) manufactured by KNF. The process of returning to atmospheric pressure over 3 minutes was repeated a total of 3 times. Then, a non-aqueous lithium-type power storage element was placed in a vacuum sealing machine, the pressure was reduced to −90 kPa, and then the aluminum laminate packaging material was sealed by sealing at 200 ° C. for 10 seconds at a pressure of 0.1 MPa.

[Calculation of energy density]
The completed non-aqueous lithium-type power storage element reaches 3.8V at a current value of 2C using a charging / discharging device (5V, 360A) manufactured by Fujitsu Telecom Networks Limited in a constant temperature bath set at 25 ° C. The constant current charging was carried out until the battery was charged, and then the constant voltage charging in which a constant voltage of 3.8 V was applied was carried out for a total of 30 minutes. After that, let Q be the capacitance when constant current discharge is performed with a current value of 2C up to 2.2V, and the capacitance F (F) calculated by F = Q / (3.8-2.2) and Using the volume V (L), the following equation:
The energy density was calculated by E / V = F × (3.8-2.2) / 2/3600 / V and found to be 36.1 Wh / L.

[Calculation of Ra / F]
The completed non-aqueous lithium power storage element reaches 3.8V at a current value of 20C using a charging / discharging device (5V, 360A) manufactured by Fujitsu Telecom Networks Co., Ltd. in a constant temperature bath set at 25 ° C. A constant current charge is performed for a total of 30 minutes, followed by a constant voltage charge of 3.8 V, followed by a constant current discharge of 20 C to 2.2 V, and the discharge curve ( Time-voltage) was obtained. In this discharge curve, the voltage at the discharge time = 0 second obtained by extrapolating from the voltage values at the time points of the discharge time of 2 seconds and 4 seconds is defined as Eo, the voltage drop ΔE = 3.8-Eo, and The room temperature internal resistance Ra was calculated from R = ΔE / (20C (current value A)).
The product Ra · F of the capacitance F and the internal resistance Ra at 25 ° C. was 2.78 ΩF.

[Calculation of Rb / Ra]
The completed non-aqueous lithium-type power storage element was left in a constant temperature bath set at -10 ° C for 2 hours, and then the charging / discharging device (5V, 5V, manufactured by Fujitsu Telecom Networks Limited) was maintained at the constant temperature bath at -10 ° C. Using 360A), constant current charging was performed at a current value of 1.0B until 3.8V was reached, followed by constant voltage charging to which a constant voltage of 3.8V was applied for a total of 2 hours. Subsequently, a constant current discharge was performed up to 2.2 V with a current value of 50 B to obtain a discharge curve (time-voltage), and the low temperature internal resistance Rb was calculated by the internal resistance calculation method.
The ratio Rb / Ra of the internal resistance Rb at −10 ° C. to the internal resistance Ra at 25 ° C. was 6.3.

[Gas generated after high temperature storage test]
The completed non-aqueous lithium-type power storage element reaches 4.0 V at a current value of 100 C using a charging / discharging device (5V, 360A) manufactured by Fujitsu Telecom Networks Limited in a constant temperature bath set at 25 ° C. It was charged with a constant current until it was charged, and then a constant voltage charge of applying a constant voltage of 4.0 V was performed for a total of 10 minutes. Then, the cell was stored in a 60 ° C environment, taken out from the 60 ° C environment every two weeks, charged to 4.0 V in the cell voltage in the same charging step, and then the cell was stored again in the 60 ° C environment. .. This step was repeated for 2 months, and the cell volume Va before the start of the preservation test and the cell volume Vb 2 months after the preservation test were measured by the Archimedes method. The amount of gas generated by Vb-Va was 8.3 × 10 ^-3 cc / F.

[Calculation of Rc / Ra]
For the power storage element after the high temperature storage test, the room temperature internal resistance Rc after the high temperature storage test was calculated in the same manner as in the above [Calculation of Ra and F].
The ratio Rc / Ra calculated by dividing this Rc (Ω) by the internal resistance Ra (Ω) before the high temperature storage test obtained in the above [Calculation of Ra / F] was 2.75.

[Nail piercing test]
The completed non-aqueous lithium-type power storage element is charged with a constant current in a constant temperature bath set at 25 ° C. until it reaches 4.0 V with a current value of 100 C, and then a constant voltage of 4.0 V is applied. Charging was performed for 10 minutes.
The power storage element whose voltage was adjusted to 4.0 V in the above step was subjected to a nail piercing test under the following conditions.
Testing machine: Shimadzu Autograph AG-X
Nail: φ2.5mm-SUS304
Environmental temperature (T2): 25 ° C
Evaluation method: After fixing the power storage element horizontally and attaching a thermocouple to the positive electrode terminal, negative electrode terminal, and the central surface of the exterior body of the power storage element, the speed is 20 mm / sec along the vertical direction at the center of the power storage element. I stabbed the nail until it penetrated. The heat generation temperature of each part during the test and the behavior of the power storage element were observed.
At the time of the test, the place where the maximum temperature reached was the negative electrode terminal, and the maximum temperature (T1) was 103 ° C. ΔT = 78 ° C. was determined according to the above calculation formula (ΔT = T1-T2).

[Lithium compound and particle size of active material]
After adjusting one of the completed non-aqueous lithium-type power storage elements to 2.9V, it is disassembled in an Ar box installed in a room at 23 ° C and controlled at a dew point of -90 ° C or less and an oxygen concentration of 1 ppm or less. Then, the positive electrode was taken out. A small piece of 1 cm × 1 cm was cut out from the obtained positive electrode, and a cross section perpendicular to the plane direction of the positive electrode sample 1 was used under the conditions of SM-09020CP manufactured by JEOL Ltd., argon gas, an acceleration voltage of 4 kV, and a beam diameter of 500 μm. Was produced. The positive electrode cross sections SEM and EDX were measured by the above method.

The image obtained from the positive cross-sectional SEM and EDX that the measurement was calculated average particle diameter Y ₁ having an average particle diameter of X ₁ and the positive electrode active material of a lithium compound by image analysis using an image analysis software (ImageJ) .. With respect to the obtained oxygen mapping, particles containing 50% or more of bright areas binarized based on the average value of brightness were designated as lithium compound particles X, and other particles were designated as positive electrode active material particles Y. The cross-sectional area S was obtained for all the particles of X and Y observed in the cross-sectional SEM image, and the particle diameter d calculated by the following mathematical formula (1) was obtained.

｛式中、円周率をπとする。｝
得られた粒子径ｄを用いて、下記数式（２）において体積平均粒子径Ｘ_０及びＹ_０を求めた。

{In the formula, let the pi be π. }
Using the obtained particle size d, the volume average particle size X ₀ and Y ₀ were obtained by the following mathematical formula (2).

正極断面の視野を変えて合計５ヶ所測定し、それぞれのＸ_０及びＹ_０の平均値である平均粒子径Ｘ_１は１．５１μｍ、Ｙ_１は４．３２μｍであった。

A total of 5 points were measured by changing the field of view of the positive electrode cross section, and the average particle size X _{1, which is the average value of X 0} and Y ₀ , was 1.51 μm, and Y ₁ was 4.32 μm.

<Analysis of positive electrode active material layer>
After adjusting the completed non-aqueous lithium-type power storage element to 2.9V, disassemble it in an Ar box installed in a room at 23 ° C and controlled at a dew point of -90 ° C or less and an oxygen concentration of 1 ppm or less, and take out the positive electrode. rice field. The removed positive electrode was immersed and washed with dimethyl carbonate (DMC), and then vacuum dried in a side box while maintaining non-exposure to the atmosphere.
The dried positive electrode was transferred from the side box to the Ar box while maintaining non-exposure to the atmosphere, and immersed in heavy water for extraction to obtain a positive electrode extract. The extraction solution was analyzed by (1) IC and (2) ¹ H-NMR, and the concentration A (mol / ml) of each compound in the positive electrode extract and the volume B (ml) of heavy water used for the extraction were obtained. ) And the mass C (g) of the positive electrode active material layer used for extraction, the following formula 4:
Abundance per unit mass (mol / g) = A × B ÷ C. .. .. (Formula 4)
The abundance (mol / g) of each compound deposited on the positive electrode active material layer per unit mass of the positive electrode active material layer was determined.
The mass of the positive electrode active material layer used for extraction was determined by the following method.
The positive electrode active material layer was peeled off from the positive electrode current collector remaining after heavy water extraction, and the peeled positive electrode active material layer was washed with water and then vacuum dried. The positive electrode active material layer obtained by vacuum drying was washed with NMP or DMF. Subsequently, the obtained positive electrode active material layer was vacuum-dried again and then weighed to examine the mass of the positive electrode active material layer used for extraction.

The analysis method of the extract is shown below.
_{(1) CO 3} ^2- derived from _{LiCO 3} Li was detected by IC measurement (negative mode) of the positive electrode extract, and the concentration A of _{CO 3} ^2- was determined by the absolute calibration curve method. The abundance (mol / g) _{of LiCO 3} Li per unit mass was determined according to Equation 1 using the concentration A, and the amount of _{LiCO 3 Li contained in the positive electrode was calculated.}

(2) The same positive electrode extract as in (1) above was placed in a 3 mmφ NMR tube (PN-002 manufactured by Shigemi Co., Ltd.), and a 5 mmφ NMR tube containing deuterated chloroform containing 1,2,4,5-tetrafluorobenzene (2). It was inserted into N-5) manufactured by Nippon Precision Science Co., Ltd., and ¹ H NMR measurement was performed by the double tube method. The signal of 1,2,4,5-tetrafluorobenzene was standardized at 7.1 ppm (m, 2H), and the integrated value of each observed compound was obtained.
Further, deuterated chloroform containing dimethyl sulfoxide having a known concentration was placed in a 3 mmφ NMR tube (PN-002 manufactured by Shigemi Co., Ltd.), and the same 1,2,4,5-tetrafluorobenzene-containing deuterated chloroform as described above was placed. It was inserted into a 5 mmφ NMR tube (N-5 manufactured by Nippon Seimitsu Kagaku Co., Ltd.) containing chloroform, and ¹ H NMR measurement was performed by the double tube method. In the same manner as above, the signal of 1,2,4,5-tetrafluorobenzene was standardized at 7.1 ppm (m, 2H), and the integrated value of the signal of dimethyl sulfoxide at 2.6 ppm (s, 6H) was obtained. From the relationship between the concentration of dimethyl sulfoxide used and the integrated value, the concentration A of each compound in the positive electrode extract was determined.

¹ The attribution of the 1 H NMR spectrum is as follows.
[About CH ₃ O-X ¹ , C ₂ H ₅ O-X ² , and X ³ OCH ₂ CH ₂ OX ³ ]
X ³ OCH ₂ CH ₂ OX ³ CH ₂ : 3.7 ppm (s, 4H)
CH ₃ OX ¹ : 3.3 ppm (s, 3H)
CH ₃ CH ₂ OX ² CH ₃ : 1.2 ppm (t, 3H)
CH ₃ CH ₂ of _{^{OX 2 CH 2 O: 3.7ppm (}} q, 2H) as described _above, the signal (3.7 ppm) is XOCH 2 _CH 2 OX of CH _2, CH ₃ CH ₂ OX of _CH 2 O Since it overlaps with the signal of CH ₃ CH _{2 OX (3.7 ppm), XOCH 2} CH is excluded except for the amount equivalent to _{CH 2} O of CH ₃ CH ₂ OX calculated from the signal of CH ₃ of CH 3 CH 2 OX (1.2 ppm). ₂ Calculate the amount of OX.
In the above chemical formula, X ¹ and X ² are − (O) _n Li or − (COO) _n Li (where n is 0 or 1), respectively. Further, X ³ is − (COO) _n Li or − (COO) _n R ¹ (where n is 0 or 1 and R ¹ is an alkyl group having 1 to 4 carbon atoms or 1 carbon atom. It is an alkyl halide group of ~ 4).

From the analysis of (1) above, it was found that the lithium carbonate contained in the positive electrode was 5.8 wt%. Further, based on the concentration of each compound in the extract obtained by the analysis of (2) above, the volume of heavy water used for extraction, and the mass of the positive electrode active material layer used for extraction, the positive electrode active material layer , CH ₃ O-X ¹ is 69.8 x ^10-6 mol / g, C ₂ H ₅ O-X ² is 32.3 x ^10-6 mol / g, X ³ OCH ₂ CH ₂ OX ³ is 131. 3 × 10 ^-4 mol / g was present.

<Analysis of negative electrode active material layer>
The negative electrode active material layer was analyzed by the same method as the analysis of the positive electrode active material layer. In the negative electrode active material layer, CH ₃ O-X ¹ was present at 6.3 × ^10-6 mol / g, and C ₂ H ₅ O-X ² was present at 5.1 × ^10-6 mol / g.

(Examples 2-28 and Comparative Examples 1-18)
In Example 1, the negative electrode, the positive electrode precursor active material, the average particle size of the positive electrode precursor active material, the lithium compound, the average particle size of the lithium compound, the composition ratio of the positive electrode precursor, and the non-aqueous solvent composition ratio of the electrolytic solution. A non-aqueous lithium-type power storage element was produced in the same manner as in Example 1 except that each of the above was used as shown in Table 1, and various evaluations were performed.
The evaluation results are shown in Tables 2 and 3.

<Example 29>
<Assembly of power storage element>
The obtained double-sided negative electrode A and double-sided positive electrode precursor A were cut into ^{10 cm × 10 cm (100 cm 2).} A single-sided positive electrode precursor A is used for the uppermost surface and the lowermost surface, and 21 double-sided negative electrode A and 20 double-sided positive electrode precursors A are used. It was sandwiched and laminated. Then, the negative electrode terminal and the positive electrode terminal were connected to the negative electrode and the positive electrode precursor by ultrasonic welding, respectively, to form an electrode laminate. This electrode laminate was vacuum dried at 80 ° C. and 50 Pa for 60 hr. This electrode laminate is inserted into an exterior body made of an aluminum laminate packaging material in a dry environment with a dew point of −45 ° C. Heat sealed. A non-aqueous lithium-type power storage element was assembled by injecting a non-aqueous electrolyte solution into the exterior body and sealing the exterior body.

<Liquid injection, impregnation, sealing process of power storage element>
Approximately 80 g of the non-aqueous electrolyte solution was injected into the electrode laminate housed in the aluminum laminate packaging material in a dry air environment with a dew point of −40 ° C. or lower under atmospheric pressure at a temperature of 25 ° C. Subsequently, the non-aqueous lithium-type power storage element was placed in the decompression chamber, the pressure was reduced from normal pressure to −87 kPa, the pressure was returned to atmospheric pressure, and the mixture was allowed to stand for 5 minutes. Then, the pressure was reduced from normal pressure to −87 kPa, the process of returning to atmospheric pressure was repeated 4 times, and then the mixture was allowed to stand for 15 minutes. Further, the pressure was reduced from normal pressure to −91 kPa, and then returned to atmospheric pressure. Similarly, the steps of depressurizing and returning to atmospheric pressure were repeated 7 times in total. (Reduced pressure to -95, 96, 97, 81, 97, 97, 97 kPa, respectively). Through the above steps, the electrode laminate was impregnated with the non-aqueous electrolyte solution.
Then, the non-aqueous lithium-type power storage element was placed in a vacuum sealing machine, and the aluminum laminate packaging material was sealed by sealing at 180 ° C. for 10 seconds at a pressure of 0.1 MPa with the pressure reduced to −95 kPa.

<Lithium dope process>
For the obtained non-aqueous lithium-type power storage element, a charging / discharging device (TOSCAT-3100U) manufactured by Toyo Systems Co., Ltd. is used, and the voltage is fixed until the voltage reaches 4.7 V at a current value of 0.2 A in an environment of 25 ° C. After the current charging, the initial charging was carried out by a method of continuing 4.7V constant voltage charging for 30 hours, and the negative electrode was lithium-doped.

<Aging process>
A non-aqueous lithium-type power storage element after lithium doping is discharged at 0.7 A at a constant current until it reaches a voltage of 3.0 V, and then charged at a constant current of 4.2 V at 1 A. Was adjusted to 4.2V. Subsequently, the non-aqueous lithium-type power storage element was stored in a constant temperature bath at 60 ° C. for 48 hours.

A non-aqueous lithium-type power storage element was produced in the same manner as in Example 2 except that the method described above was used for the power storage element assembly, liquid injection / impregnation / sealing step, lithium doping step, and aging step, and various evaluations were performed. went.
The evaluation results are shown in Tables 5 and 6.

<Example 30>

<Lithium dope process>
For the obtained non-aqueous lithium-type power storage element, a charging / discharging device (TOSCAT-3100U) manufactured by Toyo Systems Co., Ltd. is used, and the voltage is fixed until the voltage reaches 4.6 V at a current value of 0.2 A in an environment of 25 ° C. After the current charging, the initial charging was carried out by the method of continuing the 4.6V constant voltage charging for 30 hours, and the negative electrode was lithium-doped.

<Aging process>
A non-aqueous lithium-type power storage element after lithium doping is discharged at 0.7 A at a constant current until it reaches a voltage of 3.0 V, and then charged at a constant current of 4.1 V at 1 A. Was adjusted to 4.1V. Subsequently, the non-aqueous lithium-type power storage element was stored in a constant temperature bath at 60 ° C. for 48 hours.

A non-aqueous lithium-type power storage device was produced in the same manner as in Example 29 except that the lithium doping step and the aging step were carried out by the methods described above, and various evaluations were performed.
The evaluation results are shown in Tables 5 and 6.

<Example 31>

<Lithium dope process>
For the obtained non-aqueous lithium-type power storage element, a charging / discharging device (TOSCAT-3100U) manufactured by Toyo Systems Co., Ltd. is used, and the voltage is fixed until the voltage reaches 4.4 V at a current value of 0.2 A in an environment of 25 ° C. After the current charging, the initial charging was carried out by a method of continuing 4.4V constant voltage charging for 30 hours, and the negative electrode was lithium-doped.

<Aging process>
A non-aqueous lithium-type power storage element after lithium doping is discharged at 0.7 A at a constant current until it reaches a voltage of 3.0 V, and then charged at a constant current of 3.9 V at 1 A. Was adjusted to 3.9V. Subsequently, the non-aqueous lithium-type power storage element was stored in a constant temperature bath at 60 ° C. for 48 hours.

A non-aqueous lithium-type power storage device was produced in the same manner as in Example 29 except that the lithium doping step and the aging step were carried out by the methods described above, and various evaluations were performed.
The evaluation results are shown in Tables 5 and 6.

<Example 32>

<Lithium dope process>
For the obtained non-aqueous lithium-type power storage element, a charging / discharging device (TOSCAT-3100U) manufactured by Toyo Systems Co., Ltd. is used, and the voltage is fixed until the voltage reaches 4.3 V at a current value of 0.2 A in an environment of 25 ° C. After the current charging, the initial charging was carried out by the method of continuing the 4.3V constant voltage charging for 30 hours, and the negative electrode was lithium-doped.

<Aging process>
A non-aqueous lithium-type power storage element after lithium doping is discharged at 0.7 A at a constant current until it reaches a voltage of 3.0 V, and then charged at a constant current of 3.8 V at 1 A. Was adjusted to 3.8V. Subsequently, the non-aqueous lithium-type power storage element was stored in a constant temperature bath at 60 ° C. for 48 hours.

A non-aqueous lithium-type power storage device was produced in the same manner as in Example 29 except that the lithium doping step and the aging step were carried out by the methods described above, and various evaluations were performed.
The evaluation results are shown in Tables 5 and 6.

<Comparative Example 19>

<Lithium dope process>
For the obtained non-aqueous lithium-type power storage element, a charging / discharging device (TOSCAT-3100U) manufactured by Toyo Systems Co., Ltd. is used, and the voltage is fixed until the voltage reaches 5.0 V at a current value of 0.2 A in an environment of 25 ° C. After the current charge, the initial charge was carried out by a method of continuing the 5.0 V constant voltage charge for 30 hours, and the negative electrode was lithium-doped.

<Aging process>
A non-aqueous lithium-type power storage element after lithium doping is discharged at 0.7 A at a constant current until it reaches a voltage of 3.0 V, and then charged at a constant current of 4.6 V at 1 A. Was adjusted to 4.6V. Subsequently, the non-aqueous lithium-type power storage element was stored in a constant temperature bath at 60 ° C. for 48 hours.

A non-aqueous lithium-type power storage device was produced in the same manner as in Example 29 except that the lithium doping step and the aging step were carried out by the methods described above, and various evaluations were performed.
The evaluation results are shown in Tables 5 and 6.

<Comparative Example 20>

<Lithium dope process>
For the obtained non-aqueous lithium-type power storage element, a charging / discharging device (TOSCAT-3100U) manufactured by Toyo Systems Co., Ltd. is used, and the voltage is fixed until the voltage reaches 4.1 V at a current value of 0.2 A in an environment of 25 ° C. After the current charging, the initial charging was carried out by a method of continuing 4.1V constant voltage charging for 30 hours, and the negative electrode was lithium-doped.

<Aging process>
A non-aqueous lithium-type power storage element after lithium doping is discharged at a constant current of 0.7 A until it reaches a voltage of 3.0 V in a 45 ° C environment, and then charged at a constant current of 3.5 V at 1 A to obtain a voltage. Was adjusted to 3.5V. Subsequently, the non-aqueous lithium-type power storage element was stored in a constant temperature bath at 60 ° C. for 48 hours.

A non-aqueous lithium-type power storage device was produced in the same manner as in Example 29 except that the lithium doping step and the aging step were carried out by the methods described above, and various evaluations were performed.
The evaluation results are shown in Tables 5 and 6.

[Comparative Example 21]
<Manufacturing of negative electrode C>
In the production of the negative electrode A, the negative electrode C was produced by the same method except that the negative electrode current collector was a copper foil having a through hole having a thickness of 15 μm. As a result, the film thickness of the negative electrode active material layer of the negative electrode C was 40 μm per one side.

<Manufacturing of negative electrode D>
In the production of the negative electrode B, the negative electrode D was produced by the same method except that the negative electrode current collector was a copper foil having a through hole having a thickness of 15 μm. As a result, the film thickness of the negative electrode active material layer of the negative electrode D was 25 μm per one side.

<Assembly of power storage element>
The double-sided negative electrode C and the double-sided positive electrode precursor containing no lithium compound were cut into ^{10 cm × 10 cm (100 cm 2).} A lithium metal foil corresponding to 760 mAh / g per unit mass of the composite porous material A was attached to one side of the double-sided negative electrode C. A single-sided positive electrode precursor containing no lithium compound is used for the uppermost surface and the lowermost surface, and 21 double-sided negative electrode Cs and 20 double-sided positive electrode precursors that have undergone the lithium pasting step are used to form a negative electrode and a positive electrode precursor. A microporous film separator having a thickness of 15 μm was sandwiched between the layers. Then, the negative electrode terminal and the positive electrode terminal were connected to the negative electrode and the positive electrode precursor by ultrasonic welding, respectively, to form an electrode laminate. This electrode laminate was vacuum dried at 80 ° C. and 50 Pa for 60 hr. This electrode laminate is inserted into an exterior body made of a laminate film under a dry environment with a dew point of −45 ° C., and the electrode terminal portion and the bottom exterior body are heat-sealed at 180 ° C., 20 sec, and 1.0 MPa. bottom. A non-aqueous lithium-type power storage element was assembled by injecting a non-aqueous electrolyte solution and sealing the exterior body.

<Lithium dope process>
The obtained non-aqueous lithium-type power storage element was left to stand for 21 hours in a constant temperature bath set at 45 ° C. to perform lithium doping on the negative electrode.

<Aging process>
After adjusting the cell voltage of the non-aqueous lithium storage element after lithium doping to 3.0 V, it was stored for 24 hours in a constant temperature bath set at 45 ° C. Subsequently, using a charging / discharging device manufactured by Asuka Electronics, the charging current is 10A and the discharging current is 10A, and a constant current charging and a constant current discharging charging / discharging cycle are performed between the lower limit voltage of 2.0 V and the upper limit voltage of 4.0 V. Repeated times.

A non-aqueous lithium-type power storage element was produced in the same manner as in Example 2 except that the method described above was used for the power storage element assembly, lithium doping step, and aging step, and various evaluations were performed.
The evaluation results are shown in Tables 5 and 6.

(Comparative Examples 22 to 24)
A non-aqueous lithium-type power storage element was produced in the same manner as in Comparative Example 21, except that the active material of the negative electrode and the positive electrode precursor, the particle size of the active material, and the composition ratio of the positive electrode precursor were as shown in Table 4, respectively. Then, various evaluations were performed.
The evaluation results are shown in Tables 5 and 6.

The non-aqueous lithium storage element of the present invention can be suitably used as a power storage element in, for example, an automobile hybrid drive system for assisting an instantaneous power peak.
The non-aqueous lithium storage element of the present invention is preferable because the effect of the present invention is maximized when applied as, for example, a lithium ion capacitor or a lithium ion secondary battery.

Claims (25)

Positive electrode;
Negative electrode;
Separator; and non-aqueous electrolyte solution containing lithium ions;
It is a non-aqueous lithium-type power storage element containing
The negative electrode has a negative electrode current collector and a negative electrode active material layer containing a negative electrode active material provided on one side or both sides of the negative electrode current collector, and the negative electrode active material occludes lithium ions.・ Including carbon material that can be released
The positive electrode has a positive electrode current collector and a positive electrode active material layer containing a positive electrode active material provided on one side or both sides of the positive electrode current collector, and the positive electrode active material contains active carbon.
Equation CH ₃ OX ¹ {In the equation, X ¹ is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. Of the compound represented by}, wherein the content per unit mass of the positive electrode active material layer is A, and the formula _C ² _H 5 OX 2 {wherein, ^{X 2} is, - _(O) n Li or - (COO ) _N Li, and n is 0 or 1. Of a compound represented by}, when the content per unit mass of the positive electrode active material layer B, and 1.80 ≦ A / B ≦ 20.00, and,
The following formulas (1) to (3):
LiX ^I- OR ¹ O-X ^II Li (1)
{In formula (1), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and ^XI and X ^II are independently − (COO) _n. (Here, n is 0 or 1.). }
LiX ^I- OR ¹ O-X ^II R ² (2)
{In the formula (2), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and R ² is hydrogen, an alkyl group having 1 to 10 carbon atoms, and carbon. A mono or polyhydroxyalkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a mono or polyhydroxyalkenyl group having 2 to 10 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group. And X ^I and X ^II are independently − (COO) _n (where n is 0 or 1). }
R ² X ^I- OR ¹ O-X ^II R ³ (3)
{In the formula (3), R ¹ is an alkylene group having 1 to 4 carbon atoms or a halogenated alkylene group having 1 to 4 carbon atoms, and R ² and R ³ are independently hydrogen and 1 carbon atom, respectively. Alkyl groups of 10 to 10, mono or polyhydroxyalkyl groups with 1 to 10 carbon atoms, alkenyl groups with 2 to 10 carbon atoms, mono or polyhydroxyalkenyl groups with 2 to 10 carbon atoms, cycloalkyl groups with 3 to 6 carbon atoms , Or an aryl group, and ^XI and X ^II are independently − (COO) _n (where n is 0 or 1). }
Of a compound selected from among, when the content per unit mass of the positive electrode active material layer and the C, C is ^{1.60 × 10 -4 mol / g~150.0 ×} 10 -4 mol / g der is, and the positive electrode, lithium carbonate, lithium oxide, lithium hydroxide, lithium fluoride, lithium chloride, oxalate lithium, lithium iodide, one selected lithium nitride, lithium oxalate, and lithium acetate A non-aqueous lithium-type power storage element containing the above lithium compounds. The formula CH ₃ OX ¹ {in the formula, X ¹ is − (O) _n Li or − (COO) _n Li, and n is 0 or 1. Of the compound represented by}, wherein the content per unit mass of the negative electrode active material layer is D, and the formula _C ² _H 5 OX 2 {wherein, ^{X 2} is, - _(O) n Li or - ( COO) _n Li, and n is 0 or 1. Of a compound represented by}, when the E content per unit mass of the negative electrode active material layer is 1.10 ≦ D / E ≦ 15.00, nonaqueous lithium-type according to claim 1 Power storage element. When the average particle size of the lithium compound is X ₁ , it is 0.1 μm ≤ X ₁ ≤ 10 μm, and when the average particle size of the positive electrode active material is Y ₁ , it is 2 μm ≤ Y ₁ ≤ 20 μm. _{The non-aqueous lithium-type power storage element according to claim 1 or 2, wherein 1} <Y ₁ and the amount of the lithium compound contained in the positive electrode is 1% by mass or more and 50% by mass or less. The non-aqueous electrolyte solution contains dimethyl carbonate (DMC) and ethyl methyl carbonate (EMC), and the volume ratio (DMC / EMC) of the dimethyl carbonate to the ethyl methyl carbonate is 0.5 or more and 8.0 or less. The non-aqueous lithium-type power storage element according to any one of claims 1 to 3. The non-aqueous electrolyte solution according to any one of claims 1 to 4, wherein the non-aqueous electrolyte solution contains at least one organic solvent selected from the group consisting of ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate and fluoroethylene carbonate. The non-aqueous lithium-type power storage element described. The non-aqueous lithium-type power storage element according to any one of claims 1 to 5, wherein the positive electrode current collector and the negative electrode current collector are non-porous metal foils. The non-aqueous lithium power storage device according to any one of claims 1 to 6, wherein the non-aqueous electrolyte solution _{contains LiPF 6} and / or LiBF _4. Any of claims 1 to 7, wherein the concentration of LiN (SO ₂ F) _{2 in} the non-aqueous electrolyte solution is 0.3 mol / L or more and 1.5 mol / L or less based on the total amount of the non-aqueous electrolyte solution. The non-aqueous lithium-type power storage element according to item 1. The amount of mesopores derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by the BJH method for the positive electrode active material contained in the positive electrode active material layer is V1 (cc / g), and the diameter is less than 20 Å calculated by the MP method. When the amount of micropores derived from the pores is V2 (cc / g), 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0 are satisfied, and the measurement is performed by the BET method. The non-aqueous lithium-type power storage element according to any one of claims 1 to 8, which is an activated carbon having a specific surface area of 1,500 m ² / g or more and 3,000 m ^{2 / g or less.} The positive electrode active material contained in the positive electrode active material layer has a mesopore amount V1 (cc / g) of 0.8 <V1 ≦ 2.5 derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by the BJH method. The micropore amount V2 (cc / g) derived from the pores having a diameter of less than 20 Å calculated by the MP method satisfies 0.8 <V2 ≦ 3.0, and the specific surface area measured by the BET method is 2. The non-aqueous lithium-type power storage element according to any one of claims 1 to 8, which is an activated carbon exhibiting 300 m ² / g or more and 4,000 m ^{2 / g or less.} The non-aqueous lithium type according to any one of claims 1 to 10, wherein the amount of lithium ions doped in the negative electrode active material contained in the negative electrode is 530 mAh / g or more and 2,500 mAh / g or less per unit mass. Power storage element. The non-aqueous lithium-type power storage element according to any one of claims 1 to 11, wherein the negative electrode active material has a BET specific surface area of 100 m ² / g or more and 1,500 m ^{2 / g or less.} The non-aqueous lithium-type power storage element according to any one of claims 1 to 10, wherein the amount of lithium ions doped in the negative electrode active material contained in the negative electrode is 50 mAh / g or more and 700 mAh / g or less per unit mass. .. The non-aqueous lithium-type power storage element according to any one of claims 1 to 10 and 13, wherein the negative electrode active material has a BET specific surface area of 1 m ² / g or more and 50 m ^{2 / g or less.} The non-aqueous lithium-type power storage element according to claim 13 or 14, wherein the average particle size of the negative electrode active material is 1 μm or more and 10 μm or less. The initial internal resistance at a cell voltage of 4 V is Ra (Ω), the capacitance is F (F), the amount of power is E (Wh), and the volume of the exterior body containing the electrode laminate is V (L). And when the internal resistance at an ambient temperature of -10 ° C is Rb, the following requirements (a), (b), and (c) are:
(A) The product Ra / F of Ra and F is 0.3 or more and 3.0 or less.
(B) E / V is 15 or more and 50 or less.
(C) The non-aqueous lithium-type power storage element according to any one of claims 1 to 15, which simultaneously satisfies Rb / Ra of 10 or less. When the initial internal resistance at a cell voltage of 4 V is Ra (Ω) and the internal resistance at 25 ° C after storage at a cell voltage of 4 V and an environmental temperature of 60 ° C. for 2 months is Rc (Ω), the following (d) And (e) requirement:
(D) Rc / Ra is 0.3 or more and 3.0 or less.
(E) The amount of gas generated when stored for 2 months at a cell voltage of 4 V and an environmental temperature of 60 ° C. is 30 × 10 ^-3 cc / F or less at 25 ° C.
The non-aqueous lithium-type power storage element according to any one of claims 1 to 16, which satisfies the above conditions at the same time. Any of claims 1 to 17, wherein in the nail piercing test performed under the conditions of a cell voltage of 4.0 V, a nail diameter of 2.5 mmΦ, and a nail piercing speed of 20 mm / sec, the heat generation temperature ΔT at the time of the test is less than 80 ° C. The non-aqueous lithium-type power storage element according to item 1. A power storage module using the non-aqueous lithium power storage element according to any one of claims 1 to 18. A power regeneration system using the non-aqueous lithium-type power storage element according to any one of claims 1 to 18 or the power storage module according to claim 19. A power load leveling system using the non-aqueous lithium-type power storage element according to any one of claims 1 to 18 or the power storage module according to claim 19. An uninterruptible power supply system using the non-aqueous lithium-type power storage element according to any one of claims 1 to 18 or the power storage module according to claim 19. A non-contact power supply system using the non-aqueous lithium-type power storage element according to any one of claims 1 to 18 or the power storage module according to claim 19. An energy harvesting system using the non-aqueous lithium-type power storage element according to any one of claims 1 to 18 or the power storage module according to claim 19. A power storage system using the non-aqueous lithium power storage element according to any one of claims 1 to 18 or the power storage module according to claim 19.