WO2020012718A1

WO2020012718A1 - Lithium primary battery

Info

Publication number: WO2020012718A1
Application number: PCT/JP2019/011054
Authority: WO
Inventors: 貴士川口; 加藤　文生; 清水　敏之; 加藤　真一
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2018-07-12
Filing date: 2019-03-18
Publication date: 2020-01-16
Also published as: JP2021157858A

Abstract

This lithium primary battery comprises: an electrode group which includes a belt-like positive electrode, a belt-like negative electrode, and a belt-like separator, the positive electrode and the negative electrode being wound via the separator; an electrolytic solution which includes a nonaqueous solvent and lithium salt dissolved in the nonaqueous solvent; and a bottomed cylindrical battery can which contains the electrode group and the electrolytic solution. The electrolytic solution contains at least one additive selected from the group consisting of phthalimide, phthalimidine, tetrahydrophthalimide, and derivatives thereof, and the content of the additive in the electrolytic solution is 0.001 to 10 mass%. The battery can has an inner diameter of 20 mm or greater.

Description

Lithium primary battery

The present invention relates to a lithium primary battery.

Lithium primary batteries are used in many electronic devices because of their high energy density and low self-discharge. Lithium primary batteries have an extremely long storage life and can be stored for a long period of time of 10 years or more at room temperature, and thus are widely used as a main power supply and a memory backup power supply for various meters.

Patent Document 1 discloses a small-sized (17 mm in outer diameter and 45 mm in height) cylindrical lithium primary battery provided with an electrolyte containing hydroxyphthalimide. In Patent Document 1, hydroxyphthalimide is used for the purpose of suppressing an increase in internal resistance during storage of a battery in the final stage of discharge and suppressing gas generation due to decomposition of an electrolytic solution during storage of the battery in a high-temperature environment. I have.

The cylindrical lithium primary battery includes a band-shaped positive electrode and a band-shaped negative electrode, a column-shaped electrode group wound with a band-shaped separator interposed therebetween, and a bottomed cylindrical battery can housing the electrode group. . A cylindrical lithium primary battery provided with such a spiral-structured electrode group has a high output and is easy to take out a large current.

Patent Document 2 discloses a coin-shaped lithium primary battery using an electrolyte containing phthalimide. In Patent Document 2, phthalimide is used to suppress an increase in internal resistance during storage of a battery in a high-temperature environment.

JP 2015-149140 A International Publication No. 01/041247

In recent years, with the spread of smart meters, large-sized, high-capacity cylindrical lithium primary batteries (for example, C size and D size batteries) have been demanded as power sources for smart meters. In a battery having a large size, an electrode group having a large diameter is accommodated in a battery can having a large inner diameter.

However, in the case of a large cylindrical lithium primary battery, there may be a problem that the positive electrode utilization rate, which is not generated in the small cylindrical battery of Patent Document 1 or the coin battery of Patent Document 2, is significantly reduced. In a lithium primary battery, the design capacity of the positive electrode is usually smaller than the design capacity of the negative electrode, so that a decrease in the positive electrode utilization rate has a large effect on the discharge capacity of the battery.

Specifically, when the diameter of the electrode group is large, the dispersion of the electrolyte solution in the radial direction of the electrode group (the length direction of the strip-shaped positive electrode) becomes large in the latter half of the discharge, and the discharge reaction of the positive electrode is thereby impaired. The problem is to make it uniform. This is because, during discharge, the positive electrode expands in the electrode group, the separator is compressed accordingly, and the degree of compression of the separator on the center side of the electrode group on the outer side is increased. That is, a large amount of the electrolytic solution is distributed on the outer peripheral side of the electrode group, and the discharge reaction of the positive electrode proceeds excessively.

One aspect of the present disclosure includes a band-shaped positive electrode, a band-shaped negative electrode, and a band-shaped separator, wherein the positive electrode and the negative electrode are an electrode group wound via the separator, a non-aqueous solvent, and the non-aqueous solvent. An electrolytic solution containing a lithium salt dissolved in, and a bottomed cylindrical battery can containing the electrode group and the electrolytic solution, wherein the electrolytic solution comprises phthalimide, phthalimidine, tetrahydrophthalimide and derivatives thereof. The battery contains at least one additive selected from the group consisting of: a content of the additive in the electrolytic solution of not less than 0.001% by mass and not more than 10% by mass, and an inner diameter of the battery can of not less than 20 mm. Which relates to a lithium primary battery.

According to the present disclosure, in a lithium primary battery having high output and high capacity, the positive electrode utilization rate can be increased.

It is a front view which makes a part of lithium primary battery concerning one embodiment of the present invention a section.

リチウム The lithium primary battery according to the embodiment of the present invention has high output and high capacity. That is, the lithium primary battery includes a band-shaped positive electrode, a band-shaped negative electrode, and a band-shaped separator, and the positive electrode and the negative electrode are separated from each other by an electrode group wound through the separator, and a non-aqueous solvent and a lithium dissolved in a non-aqueous solvent. An electrolytic solution containing a salt, and a bottomed cylindrical battery can containing the electrode group and the electrolytic solution are provided. The inner diameter of the battery can is 20 mm or more. A columnar electrode group having a large size (having a diameter of about 20 mm or more) can be accommodated in the battery can.

The electrolyte contains at least one additive selected from the group consisting of phthalimide, phthalimidine, tetrahydrophthalimide and derivatives thereof, and the content of the additive in the electrolyte (mass ratio of the additive to the entire electrolyte). Is 0.001% by mass or more and 10% by mass or less.

Generally, when the inner diameter of the battery can is increased to 20 mm or more, a large-sized electrode group can be accommodated in the battery can, and a high battery capacity required for a smart meter or the like can be obtained. On the other hand, in the latter half of the discharge, the variation in the distribution of the electrolyte in the radial direction of the electrode group (the length direction of the belt-like positive electrode) becomes large, which makes the discharge reaction of the positive electrode non-uniform and reduces the positive electrode utilization rate. Would.

On the other hand, by using an electrolytic solution containing a specific amount of the above additive, when a large electrode group is accommodated in a battery can having an inner diameter of 20 mm or more, a decrease in the positive electrode utilization rate is suppressed, and Long-term reliability is improved. That is, when the electrolytic solution contains the additive in a specific amount, a part of the additive is reduced at the negative electrode and becomes a radical derived from the additive such as a phthalimidoketoanion radical. These radicals are appropriately diffused into the positive electrode, and are appropriately adsorbed to active sites on the positive electrode surface. This suppresses an excessive discharge reaction of the positive electrode on the outer peripheral side of the electrode group in which a large amount of the electrolytic solution is distributed, and makes the discharge reaction of the entire positive electrode uniform.

(4) When the content of the additive in the electrolytic solution is less than 0.001% by mass, the effect of the addition of the additive is reduced, and the utilization rate of the positive electrode is reduced. When the content of the additive in the electrolytic solution is more than 10% by mass, the radicals are excessively adsorbed on the active site on the positive electrode surface, so that the reaction resistance of the positive electrode increases and the utilization rate of the positive electrode decreases.

From the viewpoint of further improving the utilization rate of the positive electrode, the content of the additive in the electrolytic solution is preferably 0.01% by mass or more and 5% by mass or less.

The additive contains at least one selected from the group consisting of phthalimide, phthalimidine, tetrahydrophthalimide and derivatives thereof. Among them, phthalimide, 2-ethylphthalimide, 2-fluorophthalimide, hydroxyphthalimide, N-methylphthalimide, phthalimidine, 2-ethylphthalimidine, 2-fluorophthalimidine, hydroxyphthalimidine, N-methylphthalimidine, Tetrahydrophthalimide, potassium tetrahydrophthalimide, N-hydroxytetrahydrophthalimide, N-methyltetrahydrophthalimide are preferred. These compounds have low reactivity to a non-aqueous solvent or a lithium salt of the electrolytic solution. In addition, radicals derived from the above compounds generated by the reduction reaction at the negative electrode have high stability.

The additive has the general formula (1):

(In the general formula (1), X ¹ to X ⁴ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms, and Y ¹ Is a hydrogen atom or a potassium atom.) (Phthalimide or a derivative of phthalimide). Among them, X ¹ to X ⁴ are preferably hydrogen atoms. Alternatively, among X ¹ to X ⁴ , X ² or X ³ may be an ethyl group or a fluorine atom, and the rest may be hydrogen atoms.

The additive has the general formula (2):

(In the general formula (2), X ⁵ to X ⁸ each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms, and Y ² Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) (Phthalimide derivative). Among them, X ⁵ to X ⁸ are preferably hydrogen atoms. Y ² is preferably a hydrogen atom or a methyl group.

The additive has the general formula (3):

(In the general formula (3), X ⁹ to X ¹² each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms, and Y ³ Is a hydrogen atom or a potassium atom.) (Phthalimidine or a derivative of phthalimidine). Among them, X ⁹ to X ¹² are preferably hydrogen atoms. Alternatively, among X ⁹ to X ¹² , X ¹⁰ or X ¹¹ may be an ethyl group or a fluorine atom, and the rest may be hydrogen atoms.

The additive has the general formula (4):

(In the general formula (4), X ¹³ to X ¹⁶ are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms, and Y ⁴ Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) (Phthalimidine derivative). Among them, X ¹³ to X ¹⁶ are preferably hydrogen atoms. Y ⁴ is preferably a hydrogen atom or a methyl group.

The additive has the general formula (5):

(In the general formula (5), Y ⁵ is a hydrogen atom or a potassium atom.) (Tetrahydrophthalimide or a derivative of tetrahydrophthalimide).

The additive has the general formula (6):

(In the general formula (6), Y ⁶ is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) (Tetrahydrophthalimide derivative). Among them, Y ⁶ is preferably a hydrogen atom or a methyl group.

The compounds represented by the general formulas (1) to (6) have low reactivity to a non-aqueous solvent or a lithium salt of the electrolytic solution, and also have high stability of radicals derived from the compounds generated by a reduction reaction at the negative electrode. it is conceivable that.

から From the viewpoint of increasing the capacity, the thickness of the positive electrode is preferably 0.5 mm or more and 2.0 mm or less. In this case, the thickness of the negative electrode is, for example, 0.19 mm or more and 0.83 mm or less.

(4) When the thickness of the positive electrode is 0.5 mm or more, for example, by setting the length of the positive electrode in the range described later, the capacity can be sufficiently increased to the extent required for a smart meter. When the thickness of the positive electrode is 2.0 mm or less, the positive electrode active material is sufficiently used from the surface to the inside of the positive electrode during discharge, so that the positive electrode utilization rate is significantly improved.

Generally, when the thickness of the positive electrode is 0.5 mm or more and 2.0 mm or less, the dispersion of the electrolyte solution between the surface portion and the inside of the positive electrode increases, and the discharge reaction in the thickness direction of the positive electrode becomes uneven. There are cases.

On the other hand, by using the additive, radicals derived from the additive are adsorbed on the surface of the positive electrode, and when the thickness of the positive electrode is in the above range, the variation in the electrolyte solution distribution in the thickness direction of the positive electrode increases. Excessive discharge reaction on the surface of the positive electrode due to the above is suppressed. As a result, the discharge reaction is made uniform not only in the length direction of the positive electrode but also in the thickness direction of the positive electrode.

から From the viewpoint of further increasing the capacity and improving the utilization rate of the positive electrode, the thickness of the positive electrode is more preferably 0.5 mm or more and 1.5 mm or less.

In the case of using a battery can (C size) having an inner diameter of 24.6 ± 0.15 mm and a thickness of the positive electrode of 0.5 mm or more and 2.0 mm or less from the viewpoint of increasing the capacity and improving the utilization rate of the positive electrode, The length is preferably 90 mm or more and 530 mm or less. In this case, the length of the negative electrode is, for example, 100 mm or more and 550 mm or less. When the thickness of the positive electrode is set to 0.5 mm or more and 1.5 mm or less using the C size battery can, the length of the positive electrode is preferably 140 mm or more and 530 mm or less, and the length of the negative electrode is, for example, 150 mm or more and 550 mm or less. is there. When the thickness of the positive electrode is 0.5 mm or more and 1.0 mm or less using the C size battery can, the length of the positive electrode is preferably 230 mm or more and 530 mm or less, and the length of the negative electrode is, for example, 240 mm or more and 550 mm or less. is there.

In the case of using a battery can (D size) having an inner diameter of 33.6 ± 0.15 mm and a thickness of 0.5 mm or more and 2.0 mm or less from the viewpoint of increasing the capacity and improving the utilization rate of the cathode, The length is preferably 200 mm or more and 1050 mm or less. In this case, the length of the negative electrode is, for example, not less than 210 mm and not more than 1070 mm. When using the D-size battery can and setting the thickness of the positive electrode to 0.5 mm or more and 1.5 mm or less, the length of the positive electrode is preferably 300 mm or more and 1050 mm or less, and the length of the negative electrode is, for example, 310 mm or more and 1070 mm or less. is there. When the thickness of the positive electrode is set to 0.5 mm or more and 1.0 mm or less using the D-size battery can, the length of the positive electrode is preferably 480 mm or more and 1050 mm or less, and the length of the negative electrode is, for example, 490 mm or more and 1070 mm or less. is there.

The positive electrode contains a positive electrode active material, and manganese dioxide can be used as the positive electrode active material. The positive electrode includes, for example, a positive electrode current collector and a positive electrode mixture layer attached to the positive electrode current collector. The positive electrode mixture layer is formed, for example, such that the positive electrode current collector is embedded on both sides of a sheet-shaped positive electrode current collector. The positive electrode mixture layer may include a resin material such as a fluororesin as a binder in addition to the positive electrode active material. The positive electrode mixture layer may include a conductive material such as a carbon material as a conductive agent. The positive electrode current collector is, for example, an expanded metal, a net, or a punched metal made of stainless steel.

The negative electrode contains a negative electrode active material, and lithium metal or a lithium alloy can be used as the negative electrode active material. For example, metal lithium or a lithium alloy is extruded into a long sheet and used as a negative electrode. As the lithium alloy, an alloy such as Li-Al, Li-Sn, Li-Ni-Si, or Li-Pb is used, and a Li-Al alloy is preferable. The content of metal elements other than lithium contained in the lithium alloy is preferably 0.1% by mass or more and 5% by mass or less from the viewpoint of securing discharge capacity and stabilizing internal resistance.

(4) As the separator, a porous sheet formed of an insulating material having resistance to the internal environment of the lithium primary battery may be used. Specifically, a nonwoven fabric made of a synthetic resin, a microporous film made of a synthetic resin, and the like can be given.

The electrolytic solution contains a non-aqueous solvent, a lithium salt dissolved in the non-aqueous solvent, and the above-mentioned additive. The non-aqueous solvent is not particularly limited, but propylene carbonate, ethylene carbonate, 1,2-dimethoxyethane, γ-butyrolactone and the like can be used. As the lithium salt, lithium borofluoride, lithium hexafluorophosphate, lithium trifluoromethanesulfonate, lithium bis (fluorosulfonyl) imide, lithium bis (trifluoromethylsulfonyl) imide, or the like can be used.

ガス Gas chromatography / mass spectrometry (GCMS) can be used for analyzing components such as additives of the electrolytic solution. Specifically, an unused battery is dismantled, and the GCMS analysis is performed on the electrolyte collected from inside the battery.

Next, the lithium primary battery according to the embodiment of the present invention will be described more specifically with reference to the drawings. However, the present invention is not limited to the following embodiments.

FIG. 1 is a front view showing a cross section of a part of a cylindrical lithium primary battery according to an embodiment of the present invention.

The cylindrical lithium primary battery 10 includes a band-shaped positive electrode 1 and a band-shaped negative electrode 2 made of a sheet of lithium metal or a lithium alloy. The positive electrode 1 and the negative electrode 2 are spirally wound via a separator 3. Thus, a columnar electrode group is formed.

The electrode group is housed in a cylindrical metal case (battery can 9) having an opening together with an electrolytic solution (not shown). To prevent an internal short circuit, an upper insulating plate 6 and a lower insulating plate 7 are provided above and below the electrode group, respectively. The metal case generally contains iron, stainless steel, or the like.

The positive electrode 1 has a positive electrode current collector 1a and a positive electrode mixture layer attached to the positive electrode current collector 1a. The positive electrode 1 is provided with a portion exposing a part of the positive electrode mixture to expose the positive electrode current collector 1a, and one end of a positive electrode tab lead 4 is welded to the portion. The other end of the positive electrode tab lead 4 is welded to the inner surface of a sealing plate 8 for closing the opening of the battery can 9. One end of the negative electrode tab lead 5 is welded to the negative electrode 2. The other end of the negative electrode tab lead 5 is welded to the inner bottom surface of the battery can 9.

Hereinafter, the present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to the following examples.

<< Example 1 >>
(1) Production of positive electrode 92 parts by mass of electrolytic manganese dioxide as a positive electrode active material, 3.5 parts by mass of Ketjen black as a conductive agent, 4.5 parts by mass of polytetrafluoroethylene as a binder, and an appropriate amount And pure water were added and kneaded to prepare a positive electrode mixture in a wet state.

Next, the positive electrode mixture in a wet state is passed between a pair of rotating rolls rotating at a constant speed together with a positive electrode current collector 1a made of expanded metal having a thickness of 0.4 mm made of stainless steel, thereby forming a thinned expanded metal. The holes were filled with a positive electrode mixture, and both surfaces of the expanded metal were covered with a positive electrode mixture layer to prepare a positive electrode precursor. Thereafter, the positive electrode precursor was dried, rolled by a roll press until the thickness became 1.0 mm, and cut into a predetermined size to obtain a belt-shaped positive electrode 1.

(2) Preparation of Negative Electrode A sheet-shaped Li-Al alloy (Al content: 0.3% by mass) having a thickness of 0.4 mm was cut into a predetermined size to obtain a strip-shaped negative electrode 2.

(3) Preparation of Electrode Group The positive electrode mixture was peeled from a part of the positive electrode 1 to expose the positive electrode current collector, and a stainless steel positive electrode tab lead 4 was welded to the exposed portion. A negative electrode tab lead 5 made of nickel was welded to a predetermined portion of the negative electrode 2. The positive electrode 1 and the negative electrode 2 were spirally wound with a separator 3 interposed therebetween to form a columnar electrode group. As the separator 3, a 25 μm-thick microporous polyethylene film (porosity: 40%) was used.

(4) Preparation of electrolyte solution Lithium salt was added to a non-aqueous solvent in which propylene carbonate (PC), ethylene carbonate (EC), and 1,2-dimethoxyethane (DME) were mixed at a volume ratio of 2: 1: 2. Was dissolved in lithium trifluoromethanesulfonate at a concentration of 0.5 mol / liter to prepare an electrolytic solution. The electrolyte solution contained 0.5% by mass of phthalimide (additive a1 in Table 3) as an additive.

(5) Assembly of Cylindrical Battery The electrode group was inserted into a bottomed cylindrical iron battery can 9 with the ring-shaped lower insulating plate 7 disposed at the bottom. After the negative electrode tab lead 5 was welded to the inner bottom surface of the battery can 9 and the ring-shaped upper insulating plate 6 was arranged on the upper part of the electrode group, grooving was performed, and the positive electrode tab lead 4 was welded to the inner surface of the sealing plate 8. Next, the electrolytic solution was injected into the battery can 9, and then the opening of the battery can 9 was sealed with a sealing plate 8. Thus, a cylindrical lithium battery having the structure shown in FIG. 1 was produced.

において In the above, the size of the battery can was changed. Specifically, the inner diameter of the battery can was set to a value shown in Table 1. The thickness of the side of the battery can was adjusted in the range of 0.2 mm to 0.3 mm according to the size (dimension of the inner diameter) of the battery can. The height of the battery can was kept constant at 48.6 mm.

帯 The length of the strip-shaped positive electrode and the length of the negative electrode were changed according to the size (dimension of the inner diameter) of the battery can, and the diameter of the columnar electrode group was adjusted. Specifically, the length of the belt-shaped positive electrode was changed in the range of 14.0 mm to 484.0 mm. For example, the length of the positive electrode of the battery B5 was 139 mm. The length of the strip-shaped negative electrode was changed in the range of 28.0 mm to 498.0 mm. The width of the band-shaped positive electrode was fixed at 39 mm. The width of the strip-shaped negative electrode was fixed at 36 mm.

電池 Batteries B1 to B8 having different battery sizes (capacities) were thus manufactured. For example, the nominal capacity of the battery B5 is 3350 mAh.

Batteries A1 to A8 were produced in the same manner as batteries B1 to B8, except that phthalimide as an additive was not added to the electrolytic solution.

電池 The following evaluations were performed on the batteries A1 to A8 and B1 to B8 obtained above. The batteries B5 to B8 are examples, and the batteries A1 to A8 and B1 to B4 are comparative examples.

[Evaluation]
After leaving the battery prepared above at 60 ° C. for 2 months, the battery was discharged at a constant resistance of 1 kΩ in a 20 ° C. environment until the voltage reached 2.0 V, and the capacity at that time was measured. The ratio (percentage) of the capacity measured above to the design capacity of the positive electrode (the capacity theoretically determined based on the filling amount of the active material) was determined as the positive electrode utilization rate. In general, a lithium primary battery is designed so that the negative electrode capacity is larger than the positive electrode capacity.

Table 1 shows the evaluation results. The increase in the positive electrode utilization rate in Table 1 and Tables 2 and 4 to 8 described below indicates the increase in the positive electrode utilization rate due to the use of the additive. It refers to a value obtained by subtracting the positive electrode utilization rate of a battery manufactured under the same conditions except that no agent is added. For example, the increase in the positive electrode utilization rate of the battery B5 (6.3%) is a value obtained by subtracting the positive electrode utilization rate of the battery A5 (86.1%) from the positive electrode utilization rate of the battery B5 (92.4%). .

(4) In the high-capacity batteries A5 to A8 in which the inner diameter of the battery can was 20 mm or more, the discharge reaction of the positive electrode became non-uniform, and the positive electrode utilization was significantly reduced.

In the high-capacity batteries B5 to B8 having an inner diameter of the battery can of 20 mm or more, the addition of phthalimide to the electrolytic solution made the discharge reaction of the positive electrode uniform, so that the positive electrode utilization rate was significantly increased and the high positive electrode utilization rate was high. Rate was obtained.

In the small-capacity batteries A1 to A4 in which the inner diameter of the battery can is less than 20 mm, the diameter of the electrode group is small and the dispersion of the electrolyte solution in the radial direction of the electrode group is small, so that phthalimide is not added to the electrolyte solution. And a high positive electrode utilization rate was obtained. For this reason, in the batteries B1 to B4 having small capacities in which the inner diameter of the battery can is less than 20 mm, the utilization rate of the positive electrode is higher than that of the batteries A1 to A4 by adding phthalimide to the electrolytic solution. The increase in the positive electrode utilization was small.

<< Example 2 >>
Batteries C1 to C7 were prepared and evaluated in the same manner as the battery B1, except that the content of phthalimide in the electrolyte was changed to the value shown in Table 2. Batteries C2 to C6 are examples, and batteries C1 and C7 are comparative examples.

Table 2 shows the evaluation results.

(4) In the high-capacity batteries B5 and C2 to C6 in which the content of phthalimide in the electrolytic solution was 0.001% by mass or more and 10% by mass or less, the increase in the positive electrode utilization rate was large, and a high positive electrode utilization rate was obtained.

<< Example 3 >>
Instead of phthalimide (additive a1), additives a2 to a4, b1, b2, c1 to c4, d1, d2, e1, e2, f1, and f2 shown in Table 3 (the above general formulas (1) to (6) ) Was used. Except for the above, batteries D1 to D15 were prepared and evaluated in the same manner as battery B5. Batteries D1 to D15 are examples.

Table 4 shows the evaluation results.

電池 Also in the batteries D1 to D15 using the various additives shown in Table 3, the utilization rate of the positive electrode was significantly increased as compared with the battery A5, and a high utilization rate of the positive electrode was obtained.

<< Example 4 >>
Batteries E1 to F8 and F1 to F8 were fabricated and evaluated in the same manner as batteries A1 to A8 and B1 to B8, except that the thickness of the positive electrode was 0.4 mm. Batteries F5 to F8 are examples, and batteries E1 to E8 and F1 to F4 are comparative examples.

電池 Batteries G1 to G8 and H1 to H8 were fabricated and evaluated in the same manner as batteries A1 to A8 and B1 to B8 except that the thickness of the positive electrode was 0.5 mm. Batteries H5 to H8 are examples, and batteries G1 to G8 and H1 to H4 are comparative examples.

電池 Batteries I3 to I8 and J3 to J8 were prepared and evaluated in the same manner as batteries A3 to A8 and B3 to B8, except that the thickness of the positive electrode was 2.0 mm. Batteries J5 to J8 are examples, and batteries I3 to I8 and J3 to J4 are comparative examples.

電池 Batteries K4 to K8 and L4 to L8 were prepared and evaluated in the same manner as batteries A4 to A8 and B4 to B8 except that the thickness of the positive electrode was changed to 2.5 mm. Batteries L5 to L8 are examples, and batteries K4 to K8 and L4 are comparative examples.

The evaluation results are shown in Tables 5 to 8. Table 1 shows the case where the thickness of the positive electrode is 1.0 mm.

For high-capacity batteries H5 to H8, B5 to B8, and J5 to J8 in which the inner diameter of the battery can is 20 mm or more and the thickness of the positive electrode is 0.5 mm or more and 2.0 mm or less, phthalimide is added to the electrolyte. The increase in the positive electrode utilization was particularly large.

The lithium primary battery according to the present invention is suitably used, for example, as a power source for electronic devices such as smart meters that require high battery performance.

DESCRIPTION OF SYMBOLS 1 Positive electrode 1a Positive electrode collector 2 Negative electrode 3 Separator 4 Positive electrode tab lead 5 Negative electrode tab lead 6 Upper insulating plate 7 Lower insulating plate 8 Sealing plate 9 Battery can 10 Lithium primary battery

Claims

A band-shaped positive electrode, including a band-shaped negative electrode and a band-shaped separator, the positive electrode and the negative electrode, an electrode group wound via the separator,
An electrolyte containing a non-aqueous solvent and a lithium salt dissolved in the non-aqueous solvent,
A cylindrical battery can with a bottom that contains the electrode group and the electrolytic solution,
With
The electrolytic solution contains at least one additive selected from the group consisting of phthalimide, phthalimidine, tetrahydrophthalimide and derivatives thereof,
The content of the additive in the electrolytic solution is 0.001% by mass or more and 10% by mass or less,
The lithium primary battery, wherein the inner diameter of the battery can is 20 mm or more.
The additive has the general formula (1):

(In the general formula (1), X 1 to X 4 are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms, and Y 1 Is a hydrogen atom or a potassium atom.) The lithium primary battery according to claim 1, wherein
The additive has the general formula (2):

(In the general formula (2), X 5 to X 8 each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms, and Y 2 Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) The lithium primary battery according to claim 1, wherein
The additive has the general formula (3):

(In the general formula (3), X 9 to X 12 each independently represent a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms, and Y 3 Is a hydrogen atom or a potassium atom.) The lithium primary battery according to claim 1, wherein
The additive has the general formula (4):

(In the general formula (4), X 13 to X 16 are each independently a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom or an alkyl group having 1 to 3 carbon atoms, and Y 4 Is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) The lithium primary battery according to claim 1, wherein
The additive has the general formula (5):

(In the general formula (5), Y 5 is hydrogen atom or a potassium atom.) Is a compound represented by the lithium primary battery according to claim 1.
The additive has the general formula (6):

2. The lithium primary battery according to claim 1, wherein in the general formula (6), Y 6 is a compound represented by a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.
The lithium primary battery according to any one of claims 1 to 7, wherein the thickness of the positive electrode is 0.5 mm or more and 2.0 mm or less.