JP6316066B2 - Method for producing lithium ion secondary battery - Google Patents

Description

  The present invention relates to an electrode manufacturing method, a lithium ion secondary battery manufacturing method, and a lithium ion secondary battery.

  Generally, a lithium ion secondary battery includes a positive electrode, a negative electrode, and an electrolyte. As the positive electrode and the negative electrode, for example, an electrode having an electrode active material layer formed by applying a composition containing an electrode active material, a conductive additive and a binder to a current collector is used. In the lithium ion secondary battery, the electrode active material is an important factor related to the battery capacity, and as the negative electrode active material, for example, graphite (graphite), silicon, silicon oxide or the like is used.

  These negative electrode active materials have a function of occluding or releasing lithium ions during charge / discharge, but in the initial charge, lithium ions react irreversibly with the negative electrode active material, and a part of the lithium ions are subsequently charged / discharged. There is a problem that the battery capacity (discharge capacity) is reduced due to the malfunction. This problem is particularly remarkable when the negative electrode active material is silicon oxide. As a method for solving this problem, a treatment (pre-doping treatment) in which a negative electrode active material layer constituting a negative electrode is doped in advance with lithium ions before initial charging has been proposed (see Patent Document 1). If the irreversible reaction is caused in advance by performing a pre-doping process, the generation of the irreversible reaction and by-products can be suppressed during subsequent initial charging.

JP 2007-305521 A

  The pre-doping treatment can be performed by a method in which lithium metal is brought into contact with the negative electrode active material layer. However, lithium ions are dissolved from the lithium metal and diffused in the negative electrode active material layer, so that the entire negative electrode active material layer has lithium. It takes a long processing time to wait until ions penetrate. In the pre-doping process of Patent Document 1, since lithium metal as a lithium supply source is arranged at the end of the electrode laminate in which the positive electrode and the negative electrode are laminated, in order to uniformly dope lithium ions to the entire negative electrode Requires a very long processing time. For this reason, there exists a request | requirement of raising the efficiency of a pre dope process and improving the manufacturing efficiency of a lithium ion secondary battery.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the manufacturing method of the electrode which contributes to manufacture of a lithium ion secondary battery, the manufacturing method of a lithium ion secondary battery, and a lithium ion secondary battery.

[1] A method for producing an electrode used in a lithium ion secondary battery, wherein an electrode active material is applied to a smooth surface of a current collector, and then a plurality of locations on the surface of the current collector and the electrode active material are applied. A method for producing an electrode, comprising a puncturing step of puncturing the electrode.
[2] The method for manufacturing an electrode according to [1], wherein a plurality of through holes are provided through the electrode active material layer and the current collector formed after the application by the puncture.
[3] The method for manufacturing an electrode according to [2], wherein the plurality of through holes are provided in a dispersed manner on the application surface.
[4] The method for manufacturing an electrode according to any one of [1] to [3], wherein the puncture is performed by a punching method.
[5] The method for producing an electrode according to any one of [1] to [4], further including a doping step of doping lithium ions into the electrode obtained in the puncturing step.
[6] In the above [1] to [5], a negative electrode current collector is used as the current collector, and a negative electrode active material is used as the electrode active material to obtain a negative electrode as the electrode. The manufacturing method of the electrode as described in any one.
[7] By forming an electrode laminate in which the negative electrode obtained by the production method according to [6], a separator, and a positive electrode are laminated, and contacting the lithium metal with the electrode laminate, A method for producing a lithium ion secondary battery, wherein a negative electrode active material layer constituting a negative electrode is doped with lithium ions.
[8] The method for producing a lithium ion secondary battery according to [7], wherein the lithium metal is brought into contact with the electrode laminate including an electrolytic solution.
[9] The lithium ion secondary battery according to [7] or [8], wherein the positive electrode obtained by the manufacturing method according to any one of [1] to [5] is used. Manufacturing method.
[10] A lithium ion secondary battery comprising a plurality of through holes penetrating a current collector and an electrode active material layer constituting an electrode.

  According to the electrode manufacturing method of the present invention, an electrode active material layer can be formed on a current collector with a uniform thickness. When this electrode is pre-doped with lithium ions, since the electrode active material layer has a uniform thickness, lithium ions can be uniformly doped over the entire surface.

  According to the method for manufacturing a lithium ion secondary battery of the present invention, perforations are formed in the negative electrode current collector and the negative electrode active material layer constituting the negative electrode by puncturing performed at the time of manufacturing the negative electrode. For this reason, lithium ions can easily diffuse between the front side and the back side of the negative electrode regardless of the location where the lithium metal is brought into contact with the electrode laminate. As a result, the pre-doping process proceeds promptly, and the production efficiency of the lithium ion secondary battery can be increased. Furthermore, since the thickness of the negative electrode active material layer is uniform, it is easy to dope lithium ions uniformly throughout the negative electrode active material layer. As a result, the lithium ion secondary battery obtained by the above manufacturing method exhibits a predetermined battery capacity (capacity increase rate becomes high), and the charge / discharge reaction during use proceeds uniformly throughout the negative electrode. Characteristics (capacity maintenance ratio) can be improved.

  According to the lithium ion secondary battery of the present invention, since the through hole is provided in the electrode, the electrolyte easily diffuses into and out of the electrode active material layer constituting the electrode. As a result, since the electrochemical reaction at the electrode is sufficiently performed, battery performance equal to or higher than that of the conventional battery is easily exhibited.

It is a perspective view which shows the manufacturing method of an electrode as a comparative example. It is a perspective view which shows an example of the manufacturing method of the electrode which concerns on this invention. It is the schematic diagram which showed an example of a mode that dope lithium ion to an electrode laminated body.

<Method for producing electrode>
The following embodiment will be described as an example of the electrode manufacturing method according to the present invention.
The present embodiment is a method of manufacturing an electrode used in a lithium ion secondary battery, and after applying an electrode active material to a smooth surface of a current collector, the current collector and the electrode active material application surface It is a manufacturing method of an electrode which has a puncturing process which punctures a plurality of places.

  The electrode may be a negative electrode constituting a lithium ion secondary battery or a positive electrode. The negative electrode preferably has a structure in which a negative electrode active material layer is formed on the surface of a negative electrode current collector. The positive electrode preferably has a configuration in which a positive electrode active material layer is formed on the surface of a positive electrode current collector.

  As the current collector, for example, a flat metal foil (metal plate) having a rectangular shape in plan view can be used. It is important that the surface of the current collector is smooth. Here, the term “smooth” means that when a composition containing an electrode active material is applied to the surface, irregularities and through-holes that cause depressions or bulges that can be visually confirmed on the applied surface. Is not on the surface of the current collector.

  In the present embodiment, the current collector is not provided with a through hole in advance. The reason for this is that, as shown in FIG. 1, when a composition containing an electrode active material is applied to a plate-like current collector 100 in which through-holes 101 are provided in advance, there are places with through-holes and places without through-holes. As a result, the thickness of the electrode active material layer 102 formed on each of the electrodes varies, and the surface of the electrode active material layer 102 is uneven, or some through holes (for example, 101b) are blocked by the electrode active material layer 102. This is because there is an inconvenience that the through holes (for example, 101a) that are not blocked are scattered unevenly. Further, when the opening diameter of the through-hole 101 provided in the current collector 100 is large, it is necessary to set the viscosity of the composition quite high so that the applied composition does not flow down from the through-hole, It is difficult to apply a high-viscosity composition quickly and uniformly at a predetermined thickness without unevenness.

  Therefore, in this embodiment, as shown in FIG. 2, after applying the composition 12 containing the electrode active material to the smooth surface 10a of the current collector 10, the applied material is dried to form an electrode active material layer. A plurality of arbitrary locations on the current collector and the electrode active material application surface are punctured to form perforations or through-holes 14. Here, the case where the surface of the electrode active material layer formed after drying of the applied composition 12 is punctured is described, but the composition 12 is solidified to some extent even before the composition 12 is dried. If it is, it can puncture similarly.

  Since the surface on which the composition 12 is applied is smooth, the properties of the composition 12 are hardly restricted. For example, it is easy to apply the liquid composition 12 having a relatively low viscosity uniformly at an arbitrary thickness. As a result, the electrode active material layer 16 having a uniform thickness can be formed. The coating method of the composition 12 is not particularly limited, and a conventional method can be applied. The thickness to which the composition 12 is applied is not particularly limited, and may be appropriately adjusted according to the thickness (for example, 5 μm to 100 μm) of the electrode active material layer to be formed.

  FIG. 2 illustrates a case where a plurality of through holes 14 penetrating the current collector 10 and the electrode active material layer 16 are arranged. The plurality of through holes 14 are uniformly distributed over substantially the entire surface of the flat electrode 1. Thus, it is preferable that the through holes 14 are dispersedly arranged because the lithium ions diffuse more efficiently in the electrode 1 during the lithium ion doping treatment, and the doping treatment proceeds efficiently.

  Although FIG. 2 illustrates the case where the electrode active material layer 16 is formed on the first smooth surface 10a of the current collector 10, the electrode active material layer is also formed on the second smooth surface 10b of the current collector 10. May be. In that case, after applying the composition to both the smooth surfaces 10a and 10b, puncturing or penetrating the electrode active material layers formed on both surfaces of the current collector 10 by puncturing them together. Can be formed (not shown).

  In the electrode 1 of this embodiment formed in this way, the thickness of the electrode active material layer 16 is uniform, there is no through-hole 14 in which the electrode active material layer 16 has unintentionally entered, and a predetermined pitch. A plurality of through-holes 14 regularly arranged are formed (see FIG. 2).

  A method of puncturing a plurality of locations on the current collector and the application surface of the electrode active material after applying the composition containing the electrode active material on the smooth surface of the current collector is not particularly limited. For example, a method of pressing with a pressing die in which a plurality of pointed needles are arranged at positions corresponding to perforations or through holes formed in the current collector, or a through hole in which a plurality of holes are formed in the current collector And a method of pressing with a punching die arranged at a position corresponding to. These press processes are called puncturing by a punching method.

  When pressing with a pressing die in which a plurality of needles are arranged, if the needle diameter is small, a through-hole having an opening diameter (for example, about 1 mm) that can be clearly confirmed visually after pressing is not formed, and is visually confirmed. In some cases, a very thin through hole (this is called a perforation) that is difficult to form is formed. Similarly, when the opening diameter of the hole in the punching die is very thin, a perforation may be formed instead of the through hole. Even when the perforations are formed, the lithium ions can freely diffuse between the front side and the back side of the current collector and the electrode active material layer through the perforations, so that the effect of the present invention is exhibited.

Therefore, the diameter of the needle arranged in the pressing die used for the press and the diameter of the hole arranged in the punching die are not particularly limited, and are preferably about 0.01 mm to 5.0 mm, for example, 0.05 mm to 2 About 0.5 mm is more preferable, and about 0.1 mm to 1.0 mm is more preferable.
When it is at least the lower limit of the above range, it is possible to easily form perforations or through-holes through which lithium ions easily pass. When it is below the upper limit of the above range, the internal resistance of the electrode can be reduced and the structural strength of the electrode can be sufficiently maintained.

The pitch of the plurality of needles or holes (punching holes) arranged in the mold is not particularly limited, but can be, for example, about 0.2 mm to 15 mm.
Further, the aperture ratio of the electrode in which the through hole is formed, that is, the ratio of the area in which the through hole is vacant with respect to the area in which the through hole is not vacant is usually preferably 0.5 to 60%. From the viewpoint of suppressing the decrease in capacity, 0.5 to 10% is more preferable. The size of the aperture ratio can be controlled by adjusting the diameter and pitch of the needle (or hole) arranged in the press die.

  The plurality of needles arranged in the mold may have the same diameter or different diameters. Further, the pitch of the plurality of needles may be equal pitch or not equal pitch. The diameters and pitches of the plurality of needles can be appropriately adjusted according to the shape and size of the electrode to be manufactured. Similarly, the plurality of holes (punching holes) arranged in the mold may have the same diameter or different diameters. Further, the pitch of the plurality of holes may be equal pitch or not equal pitch. The diameter and pitch of the plurality of holes can be appropriately adjusted according to the shape and size of the electrode to be manufactured.

  The method for doping lithium ions into the electrode obtained after the puncturing step is not particularly limited, and is performed in the same manner as the dope treatment (sometimes referred to as pre-dope treatment) performed in the production of a conventional lithium ion secondary battery. Can do. For example, there are a method of electrochemically doping lithium ions into the electrode active material, a method of physically and / or chemically contacting the electrode active material layer and lithium metal, and the like. More specifically, for example, lithium metal can be disposed in the electrolytic solution, and the lithium metal can be conductively connected to the electrode.

  In the above, it demonstrated without distinguishing the case where the electrode to manufacture is a negative electrode and the case where it is a positive electrode. When manufacturing a negative electrode as the electrode, a known negative electrode current collector and negative electrode active material used in a conventional lithium ion secondary battery can be used as the current collector and electrode active material. Similarly, when producing a positive electrode as the electrode, a known positive electrode current collector and positive electrode active material can be used as the current collector and electrode active material.

<Method for producing lithium ion secondary battery>
The following embodiment will be described as an example of a method for producing a lithium ion secondary battery according to the present invention.
The present embodiment forms an electrode laminate in which a negative electrode obtained by the above-described electrode manufacturing method, a separator, and a positive electrode are laminated, and contacts the lithium metal with the electrode laminate, whereby the negative electrode Is a method for producing a lithium ion secondary battery, in which the negative electrode active material layer constituting the material is doped with lithium ions.

  FIG. 3 is a schematic view illustrating the state of the dope treatment, and shows a side surface of the electrode laminate in which the positive electrode 3, the separator 2, and the negative electrode 1 that are rectangular in plan view are laminated in this order. The negative electrode 1 constituting this electrode laminate has a negative electrode active material layer formed on both sides of the negative electrode current collector, and is laminated so that the lithium metal foil 4 is in contact with the outer negative electrode active material layer. . Although not shown, the lithium metal foil 4 may be disposed between the negative electrode 1 and the separator 2 and laminated so that the lithium metal foil 4 is in contact with the inner negative electrode active material layer. By maintaining the physical contact state in this manner, lithium ions can be diffused and doped from the lithium metal foil into the negative electrode active material layer.

  As another embodiment, when doping an electrode laminate in which a large number of repeating units of the negative electrode 1, the separator 2, and the positive electrode 3 are laminated, lithium is added to a plurality of locations (for example, both ends of the electrode laminate) of the electrode laminate. The dope speed can be increased by placing the metal in contact. Furthermore, you may accelerate | stimulate dope speed | velocity | rate by heat-processing and / or pressurizing with respect to an electrode laminated body.

  In the present embodiment, the entire negative electrode 1 is impregnated with an electrolytic solution. For this reason, elution of lithium ions from the lithium metal foil is further promoted, and the dope treatment is performed more efficiently. The type of the electrolytic solution used here is not particularly limited, and any non-aqueous solvent that is not an electrolytic solution may be used as long as it is a solvent that can elute lithium ions. However, from the viewpoint of improving the production efficiency of the lithium ion secondary battery, it is preferable to use the electrolytic solution constituting the lithium ion secondary battery also in the dope treatment.

  In the dope treatment, the electrolytic solution may be impregnated not only in the negative electrode 1 but also in the separator 2 and the positive electrode 3. Furthermore, the electrode laminate and the electrolytic solution to which the lithium metal foil is attached may be stored in a case (housing) constituting the lithium ion secondary battery in a state where the dope treatment is performed. In this housed state, the doping process for the negative electrode of lithium ions proceeds naturally. Therefore, if the case is sealed, the doping process is completed after a predetermined time. At this time, the amount of lithium metal used for the dope is set to an irreversible capacity, so that the lithium metal is completely removed (because it is dissolved) after the dope is completed, and thus the target lithium ion secondary battery is completed. Can be considered.

In the present embodiment, the positive electrode 3 constituting the electrode laminate may be a positive electrode manufactured by the above-described manufacturing method according to the present invention or a conventional commercial positive electrode.
In the positive electrode manufactured by the manufacturing method according to the present invention, at least a current collector is provided with perforations or through holes, and a positive electrode active material layer having a uniform thickness is formed. Lithium ions can be promoted to diffuse and permeate throughout the electrode stack.

As a lithium ion secondary battery that can be manufactured by the manufacturing method described above, for example, it has a negative electrode active material layer formed using a negative electrode material in which silicon oxide, a conductive additive, and a binder are blended, In addition, a battery including a negative electrode pre-doped with lithium can be given.
Such a lithium ion secondary battery has a high capacity development rate and excellent charge / discharge characteristics by using a negative electrode pre-doped with lithium. Further, in the lithium ion secondary battery manufactured by the manufacturing method according to the present invention, since a plurality of perforations or through holes are provided in at least the negative electrode, preferably the positive electrode, not only at the time of manufacturing the battery. Even during use, the electrolyte (electrolytic solution) diffuses efficiently. As a result, the battery performance of the battery can be improved.

  Hereinafter, although the material which can be used in the manufacturing method of an electrode which concerns on this invention, a lithium ion secondary battery, and its manufacturing method is illustrated, this invention is not limited to these illustrations.

[Negative electrode material]
As said negative electrode material, the thing formed by mix | blending a silicon oxide, a particulate conductive support agent, a fibrous conductive support agent, and a binder is mentioned, for example.

(Silicon oxide)
_{Examples of the} silicon oxide include those represented by the general formula “SiO _z (wherein z is any number from 0.5 to 1.5)”. Here, when the silicon oxide is viewed in “SiO” units, this SiO is amorphous SiO, or around the Si of the nanocluster so that the molar ratio of Si: SiO ₂ is about 1: 1. This is a composite of Si and SiO _{2 in} which SiO ₂ exists. SiO ₂ is presumed to have a buffering action against the expansion and contraction of Si during charging and discharging.

  The shape of the silicon oxide is not particularly limited, and for example, silicon oxide such as powder and particles can be used.

  In the negative electrode material, the ratio of the amount of silicon oxide to the total amount of silicon oxide, particulate conductive auxiliary, fibrous conductive auxiliary and binder can be set to 40 to 85% by mass, for example. The discharge capacity of the lithium ion secondary battery is further improved by the ratio of the compounding amount of silicon oxide being equal to or greater than the lower limit value, and the ratio of the compounding amount of silicon oxide is equal to or less than the upper limit value. It is easy to maintain a stable structure.

(Particulate conductive aid)
The particulate conductive aid is in the form of particles functioning as a conductive aid, and preferred examples include carbon black such as acetylene black and ketjen black; graphite (graphite); fullerene and the like.

  The particulate conductive auxiliary may be used singly or in combination of two or more. When two or more are used in combination, the combination and ratio are appropriately selected according to the purpose. That's fine.

  In the negative electrode material, the ratio of the amount of the particulate conductive additive to the total amount of silicon oxide, the particulate conductive additive, the fibrous conductive additive and the binder may be, for example, 3 to 30% by mass. it can. The proportion of the blending amount of the particulate conductive additive is more prominently obtained by using the particulate conductive additive, since the proportion of the blended conductive additive is equal to or greater than the lower limit. Is less than or equal to the above upper limit, the effect of the combined use with the fibrous conductive additive is more remarkably obtained.

(Fibrous conductive aid)
The fibrous conductive assistant is a fibrous substance that functions as a conductive assistant, and preferred examples include carbon nanotubes and carbon nanohorns.

The fibrous conductive auxiliary agent contributes to the structural stabilization of the negative electrode active material layer by forming a network structure in the entire negative electrode active material layer, preferably in the negative electrode active material layer described later, and the negative electrode active material layer. It is presumed that a conductive network is formed therein and contributes to improvement of conductivity.
The fibrous conductive assistant may be used alone or in combination of two or more. When two or more are used in combination, the combination and ratio are appropriately selected depending on the purpose. That's fine.

  In the negative electrode material, the ratio of the amount of fibrous conductive additive to the total amount of silicon oxide, particulate conductive additive, fibrous conductive additive and binder may be, for example, 1 to 25% by mass. it can. The ratio of the blending amount of the fibrous conductive additive is more prominently obtained by using the fibrous conductive additive because the ratio of the blending amount of the fibrous conductive assistant is not less than the lower limit. Is less than or equal to the above upper limit value, the effect of the combined use with the particulate conductive additive is more remarkably obtained.

  In the negative electrode material, the mass ratio (blending mass ratio) of the blending amount of “particulate conduction aid: fibrous conduction aid” can be, for example, 90:10 to 30:70. When the blending mass ratio of the particulate conductive assistant and the fibrous conductive assistant is in such a range, the effect of the combined use of the particulate conductive assistant and the fibrous conductive assistant can be obtained more remarkably.

(binder)
The binder may be a known one, and preferable examples thereof include polyacrylic acid (PAA), lithium polyacrylate (PAALi), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene copolymer (PVDF- Examples thereof include HFP), styrene butadiene rubber (SBR), polyvinyl alcohol (PVA), polyethylene oxide (PEO), polyethylene glycol (PEG), carboxymethyl cellulose (CMC), polyacrylonitrile (PAN), and polyimide (PI).
The binder may be used alone or in combination of two or more. When two or more are used in combination, the combination and ratio may be appropriately selected according to the purpose.

  In the negative electrode material, the ratio of the amount of the binder to the total amount of silicon oxide, particulate conductive auxiliary, fibrous conductive auxiliary and binder can be, for example, 3 to 30% by mass. When the proportion of the blending amount of the binder is equal to or higher than the lower limit value, the negative electrode structure is more stably maintained, and when the proportion of the blending amount of the binder is equal to or lower than the upper limit value, the discharge capacity is further improved. .

(Other ingredients)
In addition to silicon oxide, particulate conductive auxiliary, fibrous conductive auxiliary and binder, the negative electrode material may further contain other components not corresponding to these.
The other components can be arbitrarily selected according to the purpose, and a preferable solvent is a solvent for dissolving or dispersing the compounding components (silicon oxide, particulate conductive assistant, fibrous conductive assistant, binder). It can be illustrated.
Such a negative electrode material further mixed with a solvent is preferably a liquid composition having fluidity at the time of use.

The said solvent can be arbitrarily selected according to the kind of said mixing | blending component, As a preferable thing, water and an organic solvent can be illustrated.
Preferred examples of the organic solvent include alcohols such as methanol, ethanol, 1-propanol and 2-propanol; linear or cyclic amides such as N-methylpyrrolidone (NMP) and N, N-dimethylformamide (DMF); acetone And the like.
The solvents may be used alone or in combination of two or more, and when two or more are used in combination, the combination and ratio may be appropriately selected according to the purpose.

  The amount of the solvent in the negative electrode material is not particularly limited, and may be adjusted as appropriate according to the purpose. For example, when a negative electrode material, which is a liquid composition containing a solvent, is applied and dried to form a negative electrode active material layer to be described later, the liquid composition has a viscosity suitable for coating. What is necessary is just to adjust the compounding quantity of a solvent. Specifically, in the negative electrode material, the blending of the solvent so that the ratio of the total amount of the blending components other than the solvent to the total amount of the blending components is preferably 5 to 60% by mass, more preferably 10 to 35% by mass. Adjust the amount.

  When a component other than the solvent (other solid component) is blended as the other component, the proportion of the blended amount of the other solid component with respect to the total amount of the blended component other than the solvent in the negative electrode material is 10% by mass. Or less, more preferably 5% by mass or less.

The said negative electrode material can be manufactured by mix | blending the said silicon oxide, a particulate-form conductive support agent, a fibrous conductive support agent, a binder, and another component as needed.
At the time of blending each component, it is preferable to add these components and thoroughly mix them by various means. Each component may be mixed while sequentially adding them, or may be mixed after all components have been added, as long as the blended components are mixed uniformly.

  When the solvent is blended as the other component, the solvent is at least partially selected from the group consisting of the silicon oxide, the particulate conductive aid, the fibrous conductive aid, the binder, and other solid components. One or more of these components may be mixed in advance and blended as a solution or dispersion of these components.

The mixing method of each component is not specifically limited, For example, the well-known method using a stirring bar, a stirring blade, a ball mill, a stirrer, an ultrasonic disperser, an ultrasonic homogenizer, a self-revolving mixer etc. may be applied. A plurality of methods may be combined.
What is necessary is just to set suitably mixing conditions, such as mixing temperature and mixing time, according to various methods. Usually, the temperature during mixing is preferably 10 to 50 ° C, more preferably 15 to 35 ° C. Moreover, it is preferable that mixing time is 3 to 40 minutes, and it is more preferable that it is 5 to 20 minutes.

  The composition obtained by adding and mixing each component may be used as a negative electrode material as it is, or, for example, by removing a part of the blended solvent by distillation or the like, What was obtained by performing additional operations may be used as the negative electrode material.

[Negative electrode]
The negative electrode has a negative electrode active material layer formed using the negative electrode material and is pre-doped with lithium. For example, the negative electrode active material layer is on a current collector (negative electrode current collector). It has the composition provided in.

The current collector may be a known one, and preferable materials include those having conductivity such as copper (Cu), aluminum (Al), titanium (Ti), nickel (Ni), and stainless steel. it can.
Moreover, it is preferable that the said collector is a sheet form, and it is preferable that the thickness is 5 micrometers-20 micrometers.

  The thickness of the negative electrode active material layer is not particularly limited, but is preferably 5 μm to 100 μm, and more preferably 10 μm to 60 μm.

The negative electrode active material layer may be formed on the current collector using the negative electrode material.
For example, when a liquid composition containing a solvent is used as the negative electrode material, the negative electrode active material layer can be formed by coating and drying the liquid composition.

  Examples of the coating method of the liquid composition include various coating methods such as a method using various coaters such as a bar coater, a gravure coater, a comma coater, and a lip coater; a doctor blade method; a dipping method.

  The liquid composition may be dried by a known method under normal pressure or reduced pressure. And it is preferable that drying temperature is 40-180 degreeC. When the drying temperature is equal to or higher than the lower limit value, drying can be performed in a short time, and when the drying temperature is equal to or lower than the upper limit value, the effect of suppressing the oxidation of the current collector is increased. The drying time may be appropriately adjusted according to the drying temperature, and can be, for example, 12 to 48 hours.

  The negative electrode active material layer may be formed directly on the current collector, or may be formed on another base material and then transferred onto the current collector, and may be pressure-bonded on the current collector. Good. And also when forming a negative electrode active material layer directly on a collector, you may make it crimp on a collector.

The negative electrode is further pre-doped with lithium, and at least the negative electrode active material layer is pre-doped with lithium.
As a method for pre-doping lithium, for example, the negative electrode active material layer is preferably brought into contact with an electrolytic solution, and the contact surface with the electrolytic solution is further brought into contact with lithium metal. By applying such a method, lithium can be pre-doped more easily in a wide range of the negative electrode. The electrolytic solution to be contacted is preferably the same as the electrolytic solution used when producing a lithium ion secondary battery using this negative electrode.
The lithium metal to be contacted is preferably in the form of a sheet (lithium metal foil).
Lithium pre-doping needs to be performed using lithium metal (Li) instead of lithium ions (Li ⁺ ).

The amount of lithium pre-doped on the negative electrode is preferably 1 to 4 times the molar amount, more preferably 2 to 4 times the molar amount of silicon dioxide (SiO ₂ ) in the negative electrode active material layer. The molar amount is preferably 3 to 4 times.

Since the negative electrode is pre-doped with lithium, it is presumed that this lithium reacts irreversibly with silicon dioxide in the negative electrode active material layer to generate lithium silicate (Li ₄ SiO ₄ ) in advance. . In addition, the lithium ion secondary battery having such a negative electrode suppresses the occurrence of the irreversible reaction and by-products with silicon oxide in the negative electrode active material layer even when lithium is occluded in the negative electrode in the initial charging step. Therefore, it is presumed that the discharge during discharge is not hindered and the decrease in discharge capacity is suppressed. Therefore, this lithium ion secondary battery becomes a battery excellent in charge / discharge characteristics.

  The configuration other than the negative electrode of the lithium ion secondary battery can be the same as that of a conventional lithium ion secondary battery. For example, the negative electrode, the positive electrode, and an electrolyte solution, a gel electrolyte, or a solid electrolyte are provided. Further, if necessary, a separator may be provided between the negative electrode and the positive electrode.

[Positive electrode]
The positive electrode may be a known positive electrode that constitutes a conventional lithium ion secondary battery, and is formed using a positive electrode material in which a positive electrode active material, a binder, a solvent, and a conductive auxiliary agent are blended as necessary. The thing provided with the positive electrode active material layer on the electrical power collector (positive electrode electrical power collector) can be illustrated. A commercially available positive electrode may be used as the positive electrode.

  The binder, solvent and current collector in the positive electrode may all be the same as the binder, solvent and current collector in the negative electrode.

The conductive auxiliary in the positive electrode may be a known one, and preferable examples thereof include graphite (graphite); carbon black such as ketjen black and acetylene black; carbon nanotube; carbon nanohorn; graphene; fullerene.
The conductive auxiliary in the positive electrode may be used alone or in combination of two or more. When two or more are used in combination, the combination and ratio are appropriately selected according to the purpose. That's fine.

As the positive electrode active material, a lithium metal acid compound represented by the general formula “LiM _x O _y (wherein M is a metal; x and y are composition ratios of metal M and oxygen O)” Can be illustrated.
Examples of such a metal acid lithium compound include lithium cobaltate (LiCoO ₂ ), lithium nickelate (LiNiO ₂ ), lithium manganate (LiMn ₂ O ₄ ), and the like, and olivine iron phosphate having a similar composition. Lithium (LiFePO ₄ ) can also be used.
In the above general formula, M may be a plurality of types of the lithium metal acid compound. As such a metal acid lithium compound, the general formula “LiM ¹ _p M ² _q M ³ _r O _y (formula Where M ¹ , M ² and M ³ are different types of metals; p, q, r and y are the composition ratios of the metals M ¹ , M ² and M ³ and oxygen O). What is represented can be exemplified. Here, p + q + r = x.
Examples of such a metal acid lithium compound include LiNi _0.33 Mn _0.33 Co _0.33 O ₂ .
A positive electrode active material may be used individually by 1 type, may use 2 or more types together, and when using 2 or more types together, the combination and ratio may be suitably selected according to the objective.

  The ratio of the amount of each of the positive electrode active material, the binder, the solvent, and the conductive additive to the total amount of the compounding components in the positive electrode material is the ratio of the negative electrode active material and the binder to the total amount of the compounding components in the negative electrode material. , The solvent, and the proportion of each of the conductive additives can be the same.

  Although the thickness of a positive electrode active material layer is not specifically limited, It is preferable that it is 20-60 micrometers.

  The positive electrode active material layer can be formed by the same method as in the case of the negative electrode active material layer except that a positive electrode material is used instead of the negative electrode material.

[Electrolyte]
As the electrolytic solution, (A) lithium carboxylate, (B) boron trifluoride and / or boron trifluoride complex, and (C) an organic solvent (hereinafter referred to as “first electrolysis”). (It may be abbreviated as “liquid”).

  (A) Lithium carboxylic acid salt is an electrolyte, and an aliphatic carboxylic acid, an alicyclic carboxylic acid, and a fragrance as long as the carboxy group constitutes a lithium salt (—C (═O) —OLi). Any lithium salt of a group carboxylic acid may be used, and any lithium salt of a monovalent carboxylic acid and a polyvalent carboxylic acid may be used. And as for (A) carboxylic acid lithium salt, the number of the carboxy group which comprises lithium salt is not specifically limited. For example, when the number of carboxy groups is 2 or more, all the carboxy groups may constitute a lithium salt, or only some of the carboxy groups may constitute a lithium salt.

(A) Preferred lithium carboxylate is lithium formate (HCOOLi), lithium acetate (CH ₃ COOLi), lithium propionate (CH ₃ CH ₂ COOLi), lithium butyrate (CH ₃ (CH ₂ ) ₂ COOLi) , Lithium isobutyrate ((CH ₃ ) ₂ CHCOOLi), lithium valerate (CH ₃ (CH ₂ ) ₃ COOLi), lithium isovalerate ((CH ₃ ) ₂ CHCH ₂ COOLi), lithium caproate (CH ₃ (CH _{2) 4} COOLi) 1 monovalent lithium salts of carboxylic acids such as, lithium oxalate _((COOLi) 2), lithium malonate _(LiOOCCH 2 COOLi), lithium succinate _{((CH 2 COOLi) 2)} , lithium glutarate ( LiOOC (CH ₂ ) ₃ COOLi), adipine Lithium salt of a divalent carboxylic acid such as lithium acid ((CH ₂ CH ₂ COOLi) ₂ ); lithium salt of a monovalent carboxylic acid having a hydroxyl group such as lithium lactate (CH ₃ CH (OH) COOLi); lithium tartrate (( CH (OH) COOLi) ₂ ), lithium salt of a divalent carboxylic acid having a hydroxyl group such as lithium malate (LiOOCCH ₂ CH (OH) COOLi); lithium maleate (LiOOCCH = CHCOOLi, cis body), lithium fumarate ( Lithium salt of unsaturated divalent carboxylic acid such as LiOOCCH = CHCOOLi, trans isomer); lithium salt of trivalent carboxylic acid such as lithium citrate (LiOOCCH ₂ C (COOLi) (OH) CH ₂ COOLi) (3 having a hydroxyl group) Lithium salt of divalent carboxylic acid), and lithium formate Lithium acetate, lithium oxalate, and lithium succinate are more preferable, and lithium oxalate is particularly preferable.

  (A) Lithium carboxylate may be used individually by 1 type, and may use 2 or more types together. When two or more kinds are used in combination, the combination and ratio may be appropriately selected according to the purpose.

(B) Boron trifluoride and boron trifluoride complex are those that undergo a complex formation reaction with (A) lithium carboxylate, and boron trifluoride complex is different from boron trifluoride (BF ₃ ). Coordinated to the component.

Preferred examples of the boron trifluoride complex include boron trifluoride dimethyl ether complex (BF ₃ .O (CH ₃ ) ₂ ), boron trifluoride diethyl ether complex (BF ₃ .O (C ₂ H ₅ ) ₂ ), three Boron fluoride di n-butyl ether complex (BF ₃ · O (C ₄ H ₉ ) ₂ ), boron trifluoride di tert-butyl ether complex (BF ₃ · O ((CH ₃ ) ₃ C) ₂ ), trifluoride Boron trifluoride alkyl ether complexes such as boron tert-butyl methyl ether complex (BF ₃ .O ((CH ₃ ) ₃ C) (CH ₃ )), boron trifluoride tetrahydrofuran complex (BF ₃ .OC ₄ H ₈ ) Boron trifluoride methanol complex (BF ₃ · HOCH ₃ ), boron trifluoride propanol complex (BF ₃ · HOC ₃ H ₇ ), boron trifluoride phenol A boron trifluoride alcohol complex such as a complex (BF ₃ .HOC ₆ H ₅ ) can be exemplified.
(B) As boron trifluoride and / or boron trifluoride complex, it is preferable to use the boron trifluoride complex from the viewpoint that it is easy to handle and the complex formation reaction proceeds more smoothly.

  (B) As boron trifluoride and / or a boron trifluoride complex, 1 type may be used independently and 2 or more types may be used together. When two or more kinds are used in combination, the combination and ratio may be appropriately selected according to the purpose.

  The blending amount of (B) boron trifluoride and / or boron trifluoride complex is not particularly limited, and (B) boron trifluoride and / or boron trifluoride complex or (A) lithium carboxylate type What is necessary is just to adjust suitably according to. Usually, the molar ratio of [(B) Boron trifluoride and / or boron trifluoride complex (mole number)] / [Mixed (A) moles of lithium atoms in carboxylic acid lithium salt] Is preferably 0.5 or more, and more preferably 0.7 or more. By setting it as such a range, the solubility of (A) lithium carboxylic acid salt with respect to the (C) organic solvent improves more. The upper limit of the molar ratio is not particularly limited, but is preferably 2.0, and more preferably 1.5.

(C) Although the organic solvent is not particularly limited, specific examples of preferable organic solvents include carbonate compounds such as ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, vinylene carbonate; γ-butyrolactone, etc. Lactone compounds; carboxylic acid ester compounds such as methyl formate, methyl acetate, and methyl propionate; ether compounds such as tetrahydrofuran and dimethoxyethane; nitrile compounds such as acetonitrile; and sulfone compounds such as sulfolane.
(C) An organic solvent may be used individually by 1 type, and may use 2 or more types together. When two or more kinds are used in combination, the combination and ratio may be appropriately selected according to the purpose.

(C) The organic solvent is ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, vinylene carbonate, γ-butyrolactone, tetrahydrofuran, dimethoxyethane, methyl formate, methyl acetate, methyl propionate, acetonitrile and It is preferably at least one selected from the group consisting of sulfolane.
(C) The organic solvent used in combination of two or more types is a mixed solvent in which propylene carbonate and vinylene carbonate are blended, a mixed solvent in which propylene carbonate and ethylene carbonate are blended, and a mixed solvent in which ethylene carbonate and dimethyl carbonate are blended. Is preferred.

  The blending amount of the (C) organic solvent in the electrolytic solution is not particularly limited, and may be appropriately adjusted according to, for example, the type of the electrolyte. Usually, the blending amount may be adjusted so that the concentration of lithium atoms (Li) is preferably 0.2 to 3.0 mol / kg, more preferably 0.4 to 2.0 mol / kg. preferable.

Examples of the first electrolytic solution include a mixture of (E) a carboxylic acid lithium salt-boron trifluoride complex and (C) an organic solvent.
(E) As a carboxylic acid lithium salt-boron trifluoride complex, boron trifluoride (BF ₃ ) is coordinated to at least one carboxy group or lithium carboxy group in the carboxylic acid lithium salt. What was combined can be illustrated.
(E) As a carboxylic acid lithium salt which comprises a carboxylic acid lithium salt-boron trifluoride complex, the thing similar to (A) carboxylic acid lithium salt can be illustrated.

  The (E) carboxylic acid lithium salt-boron trifluoride complex contains, for example, (A) a lithium carboxylic acid salt, (B) boron trifluoride and / or boron trifluoride complex, and (C ′) a solvent. (A) a carboxylic acid lithium salt and (B) boron trifluoride and / or boron trifluoride complex are reacted (hereinafter abbreviated as “reaction process”), and the reaction after the reaction. A step of removing (C ′) solvent and (B) impurities derived from boron trifluoride and / or boron trifluoride complex from the liquid (hereinafter abbreviated as “removal step”). It can be manufactured by a manufacturing method. The (E) carboxylic acid lithium salt-boron trifluoride complex obtained by such a production method is such that (A) lithium carboxylic acid salt and (B) boron trifluoride and / or boron trifluoride complex are complexed. It has been formed by reaction.

  In this production method, (A) lithium carboxylate, (B) boron trifluoride and / or boron trifluoride complex are the same as described above. That is, (E) “lithium carboxylate” in the lithium carboxylate-boron trifluoride complex is the same as (A) the lithium carboxylate.

  (E) A lithium carboxylate-boron trifluoride complex may be used alone or in combination of two or more. When two or more kinds are used in combination, the combination and ratio may be appropriately selected according to the purpose.

  The (C ′) solvent does not interfere with the complex formation reaction of (A) lithium carboxylic acid salt with (B) boron trifluoride and / or boron trifluoride complex in the reaction step, and can dissolve these. Although it will not specifically limit if it is a thing, An organic solvent is preferable and what can be distilled off under a normal pressure or pressure reduction is preferable.

  The boiling point of (C ′) solvent is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and particularly preferably 35 ° C. or higher. The boiling point of the (C ′) solvent is preferably 180 ° C. or lower, more preferably 150 ° C. or lower, and particularly preferably 120 ° C. or lower. (C ′) Since the boiling point of the solvent is not less than the lower limit, the reaction solution in the reaction step can be stirred at room temperature, so that the reaction step can be performed more easily. In addition, when the boiling point of the (C ′) solvent is not more than the above upper limit value, the (C ′) solvent can be more easily removed by distillation in the removing step.

(C ′) Preferred organic solvents in the solvent include chain carbonate compounds such as dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate (compounds having a carbonate ester bond in the chain structure); nitrile compounds such as acetonitrile; Cyclic ether compounds such as tetrahydrofuran (compounds having an ether bond in the cyclic structure); chain ether compounds such as diethyl ether and 1,2-dimethoxyethane (compounds having an ether bond in the chain structure); ethyl acetate, acetic acid Examples thereof include carboxylic acid ester compounds such as isopropyl.
Among these, as the organic solvent, a chain carbonate compound, a nitrile compound, and a cyclic ether compound are preferable.

  (C ') A solvent may be used individually by 1 type and may use 2 or more types together. When two or more kinds are used in combination, the combination and ratio may be appropriately selected according to the purpose.

  In the removal step, as the impurities, (A) an excessive amount of (B) boron trifluoride and / or boron trifluoride complex remaining without reacting with the carboxylic acid lithium salt, and by-products generated therefrom More specifically, as the by-product, in the boron trifluoride complex which is the component (B), a component that was originally coordinated to boron trifluoride before the reaction can be exemplified. These impurities can be distilled off.

  (E) The 1st electrolyte solution using the lithium carboxylate-boron trifluoride complex is, for example, (A) lithium carboxylate and (B) boron trifluoride and / or boron trifluoride complex. Instead of blending, (E) by mixing a carboxylic acid lithium salt-boron trifluoride complex, (A) a carboxylic acid lithium salt, and (B) boron trifluoride and / or boron trifluoride complex. Can be obtained by the same method as the above-described first electrolytic solution. For example, the amount of (C) the organic solvent is not particularly limited, but the concentration of lithium atoms (Li) is preferably 0.2 to 3.0 mol / kg, more preferably 0.4 to 2.0 mol / kg. It is preferable to adjust the blending amount so as to be kg.

Further, as the electrolyte, lithium hexafluorophosphate as an electrolyte (LiPF _6), boron tetrafluoride lithium (LiBF _4), lithium bisfluorosulfonylimide (LiFSI), bis (trifluoromethanesulfonyl) imide (LiN (SO ₂ CF ₃ ) ₂ , LiTFSI) or other known lithium salt other than (A) carboxylic acid lithium salt dissolved in an organic solvent (hereinafter abbreviated as “second electrolyte solution”) There are also examples).

  The said electrolyte in a 2nd electrolyte solution may be used individually by 1 type, and may use 2 or more types together. When two or more kinds are used in combination, the combination and ratio may be appropriately selected according to the purpose.

Examples of the organic solvent in the second electrolytic solution are the same as the organic solvent (C) in the first electrolytic solution.
The concentration of lithium atoms (Li) in the second electrolytic solution is the same as that in the first electrolytic solution.

The first and second electrolytic solutions are both the above-mentioned essential components ((A) lithium carboxylic acid salt, (B) boron trifluoride and / or boron trifluoride complex in the first electrolytic solution, (E In addition to (a) a carboxylic acid lithium salt-boron trifluoride complex, (C) an organic solvent; a lithium salt in the second electrolytic solution, an organic solvent), an optional component is blended within the range not impairing the effects of the present invention. It may be.
The arbitrary component may be appropriately selected according to the purpose and is not particularly limited.

  The 1st and 2nd electrolyte solution can be manufactured by mix | blending the said essential component and an arbitrary component as needed. The compounding method of each component is the same as the compounding method of each component at the time of manufacture of the said negative electrode material. However, the composition at the time of mixing is not particularly limited.

  The electrolyte includes (A) a lithium carboxylate and (B) boron trifluoride and / or boron trifluoride complex, or (E) a carboxylate lithium salt-boron trifluoride complex. That is, the first electrolytic solution is preferable.

[Gel electrolyte]
As the gel electrolyte, (A) lithium carboxylate, (B) boron trifluoride and / or boron trifluoride complex, (C) an organic solvent, and (D) a matrix polymer are blended; E) A mixture of a lithium carboxylate-boron trifluoride complex, (C) an organic solvent, and (D) a matrix polymer can be exemplified, and if necessary, in the first and second electrolytic solutions An arbitrary component may be blended. Moreover, as said gel electrolyte, what further mix | blended (D) matrix polymer with the 1st electrolyte solution can be illustrated. Here, (A) carboxylic acid lithium salt, (B) boron trifluoride and / or boron trifluoride complex, (E) carboxylic acid lithium salt-boron trifluoride complex, and (C) organic solvent are any Is the same as in the first electrolyte solution.

The gel electrolyte may be molded into a desired shape using a mold.
In the gel electrolyte, components (electrolytic solution) other than (D) the matrix polymer are retained in the matrix polymer.

  The gel electrolyte may be one in which a part of the blended (C) organic solvent is removed by drying or the like, and an organic solvent (for dilution) different from the (C) organic solvent mainly remaining in the gel electrolyte at the time of production. Organic solvent) may be blended separately, and the organic solvent for dilution may be removed during the drying.

(D) A matrix polymer is not specifically limited, A well-known thing can be used suitably in the solid electrolyte field | area.
Preferred (D) matrix polymers include polyether polymers such as polyethylene oxide and polypropylene oxide (polymers having a polyether skeleton); polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, and polyfluoride. Fluorine-based polymers (polymers having fluorine atoms) such as vinylidene fluoride-hexafluoroacetone copolymer, polytetrafluoroethylene; poly (meth) methyl acrylate, poly (meth) ethyl acrylate, polyacrylamide, ethylene oxide units Examples include polyacrylic polymers such as polyacrylates (polymers having structural units derived from (meth) acrylates or acrylamides); polyacrylonitriles; polyphosphazenes; polysiloxanes Kill.

  (D) A matrix polymer may be used individually by 1 type, and may use 2 or more types together. When two or more kinds are used in combination, the combination and ratio may be appropriately selected according to the purpose.

  (D) The matrix polymer is polyethylene oxide, polypropylene oxide, polyvinyl fluoride, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyvinylidene fluoride-hexafluoroacetone copolymer, polytetrafluoroethylene, It is preferably at least one selected from the group consisting of polyacrylonitrile, polyphosphazene and polysiloxane.

  In the gel electrolyte, the blending amount of the (D) matrix polymer is not particularly limited, and may be appropriately adjusted according to the type, but the ratio of the blending amount of the (D) matrix polymer to the total amount of blending components is 2-50. It is preferable that it is mass%. (D) When the blending amount of the matrix polymer is equal to or greater than the lower limit, the strength of the gel electrolyte is further improved, and (D) the blending amount of the matrix polymer is equal to or smaller than the upper limit, the lithium ion secondary battery Indicates better battery performance.

The organic solvent for dilution is preferably one that can sufficiently dissolve or disperse any of the components. Specifically, nitrile compounds such as acetonitrile; ether compounds such as tetrahydrofuran: amide compounds such as dimethylformamide It can be illustrated.
The organic solvent for dilution may be used individually by 1 type, and may use 2 or more types together. When two or more kinds are used in combination, the combination and ratio may be appropriately selected according to the purpose.

  The gel electrolyte is preferably one that does not exhibit fluidity in an environment of 40 ° C. or lower where a lithium ion secondary battery is normally used.

The blending method of each component at the time of manufacturing the gel electrolyte may be the same as in the case of the electrolytic solution.
The drying method for removing the diluting organic solvent is not particularly limited, and for example, a known method using a dry box, a vacuum desiccator, a vacuum dryer or the like may be applied.

[Solid electrolyte]
As the solid electrolyte, a composition obtained by blending (A) a lithium carboxylate, (B) boron trifluoride and / or boron trifluoride complex, an organic solvent for dilution, and (D) a matrix polymer. And (E) a composition obtained by blending a lithium carboxylate-boron trifluoride complex, an organic solvent for dilution, and (D) a matrix polymer, the organic solvent for dilution is removed by drying. And may be formed by blending arbitrary components in the first and second electrolytic solutions as necessary. Here, (A) carboxylic acid lithium salt, (B) boron trifluoride and / or boron trifluoride complex, (E) carboxylic acid lithium salt-boron trifluoride complex, and (C) organic solvent are any Are the same as those in the first electrolyte solution, and the organic solvent for dilution and (D) the matrix polymer are the same as those in the gel electrolyte.

  The solid electrolyte may be molded into a desired shape using a mold.

  In the solid electrolyte, the blending amount of the (D) matrix polymer is not particularly limited, and may be appropriately adjusted according to the type, but the ratio of the blending amount of the (D) matrix polymer to the total amount of blending components is 2 to 65. It is preferable that it is mass%. (D) When the blending amount of the matrix polymer is equal to or higher than the lower limit, the strength of the solid electrolyte (electrolyte membrane) is further improved, and (D) the blending amount of the matrix polymer is equal to or lower than the upper limit, Ion secondary batteries exhibit better battery performance.

The blending method of each component during the production of the solid electrolyte may be the same as in the case of the electrolytic solution.
The drying method for removing the diluting organic solvent may be the same as that for the gel electrolyte.

[Separator]
Although the material of the separator is not particularly limited, it can be exemplified by a microporous polymer film, a nonwoven fabric, glass fiber, and the like, and is preferably at least one selected from the group consisting of these materials.

FIG. 3 is a front view schematically illustrating the main part (electrode laminate) of the lithium ion secondary battery according to the present invention. The lithium metal foil 4 is not included in the completed battery configuration.
In the lithium ion secondary battery shown here, a sheet-like negative electrode 1 and a positive electrode 3 are laminated via a separator 2. The separator 2 may be composed of a single layer or may be composed of a plurality of layers in which two or more layers are laminated. In FIG. 3, the electrolytic solution is not shown. As a lithium ion secondary battery using a gel electrolyte or a solid electrolyte instead of the electrolytic solution, a battery provided with a gel electrolyte or a solid electrolyte instead of the separator 2 or a gel electrolyte or a solid electrolyte containing a separator can be exemplified.

  Here, each of the negative electrode 1 and the positive electrode 3 is shown one by one. However, the repeating structure of the repeating unit is repeated so that the negative electrode 1, the separator 2 and the positive electrode 3 are stacked in this order, and this order is repeated. A configuration in which a plurality of the laminated structures are repeatedly laminated with a separator 2 interposed therebetween may be employed.

What is necessary is just to manufacture the said lithium ion secondary battery according to a well-known method, for example in the glove box or a dry air atmosphere, using the said electrolyte solution, a gel electrolyte, or a solid electrolyte, an electrode, etc.
For example, in the case of a lithium ion secondary battery equipped with a gel electrolyte, a gel electrolyte heated to a liquid state is applied onto one or both of the negative electrode and the positive electrode, and then the gel electrolyte is used. It can manufacture easily by laminating | stacking the negative electrode and positive electrode which were equipped through the gel electrolyte so that these electrode surfaces may oppose, and interposing a separator between these electrode surfaces as needed. The liquid gel electrolyte can be coated on the electrode surface by a method using various coaters such as a bar coater.
Further, for example, in the case of a lithium ion secondary battery provided with an electrolytic solution, the gel electrolyte described above is used except that the electrolytic solution is placed in contact with the electrode surfaces of the negative electrode and the positive electrode instead of the gel electrolyte. It can be easily manufactured by the same method as the provided lithium ion secondary battery.

  The shape of the lithium ion secondary battery is not particularly limited, and can be adjusted to various shapes such as a cylindrical shape, a square shape, a coin shape, and a sheet shape.

  When a lithium ion secondary battery uses (A) lithium carboxylate and (B) boron trifluoride and / or boron trifluoride complex or (E) lithium carboxylate-boron trifluoride complex, An interfacial film containing lithium fluoride (LiF) (hereinafter abbreviated as “SEI”) is formed on the negative electrode surface during initial charging. This SEI prevents solvent molecules solvated with lithium ions from entering the negative electrode during charge and discharge, suppresses destruction of the negative electrode structure, and contributes to improvement of the cycle characteristics of the lithium ion secondary battery.

  The present invention can be used in the field of lithium ion secondary batteries.

DESCRIPTION OF SYMBOLS 1 ... Negative electrode, 2 ... Separator, 3 ... Positive electrode, 4 ... Lithium metal foil, 10 ... Current collector, 12 ... Composition (electrode material) containing an electrode active material, 14 ... Through-hole, 16 ... Electrode active material layer, DESCRIPTION OF SYMBOLS 100 ... Current collector, 101 ... Through-hole, 102 ... Electrode active material layer

Claims (2)

A method for producing a lithium ion secondary battery, comprising:
After applying the electrode active material to the smooth surface of the current collector, puncture a plurality of locations on the current collector and the electrode active material application surface,
A plurality of through holes penetrating through the electrode active material layer formed after the application and the current collector by the puncture are provided on the application surface,
A step of obtaining a negative electrode and a positive electrode in which the opening ratio represented by the ratio of the open area of the through hole to the open area of the through hole is 0.5 to 10%;
Configuration wherein a negative electrode, a separator, the positive electrode and forms an electrode laminate formed by stacking said impregnated with electrode stack in an electrolyte solution, by contacting the lithium metal in the electrode stack, the anode And a doping step of doping lithium ions into the negative electrode active material layer ,
Lithium ion, wherein the electrolyte is an electrolyte containing (A) a lithium carboxylate, (B) boron trifluoride and / or boron trifluoride complex, and (C) an organic solvent. A method for manufacturing a secondary battery. The method of manufacturing a lithium ion secondary battery according to claim 1, wherein the puncturing is performed by a punching method.