JP2013127857A - Lithium ion battery and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lithium ion battery which inhibits internal short circuits due to metal foreign objects, improves the reliability, and is advantageous in terms of cost, and to provide a manufacturing technique of the lithium ion battery.SOLUTION: According to one embodiment 1, a separator SP1 and a separator SP2 are bonded to both surfaces of a positive electrode PEL. This structure prevents a gap from occurring between the positive electrode PEL and the separator SP1 or between the positive electrode PEL and the separator SP2. The positive electrode PEL, the separator SP1, and the separator SP2 are integrally formed in this way. Here, the separator SP1 (SP2) is formed by, for example, a material including a binder, a ceramic that is an insulating material, and an organic material.

Description

  The present invention relates to a lithium ion battery and a manufacturing technique thereof, and more particularly, to a lithium ion battery including a positive electrode, a negative electrode, and a separator that electrically separates the positive electrode and the negative electrode, and a technique effective when applied to the manufacturing technique. .

  As background art in this technical field, there is JP-A-2006-139978 (Patent Document 1). Patent Document 1 describes an example in which a positive electrode or a negative electrode and a separator are integrated.

JP 2006-139978 A

  With the development of portable electronic devices, small secondary batteries that can be repeatedly charged are used as power supply sources for these portable electronic devices. Of these, lithium ion batteries are attracting attention because of their high energy density, long cycle life, low self-discharge characteristics, and high operating voltage. Lithium ion batteries have the advantages described above, and are therefore widely used in portable electronic devices such as digital cameras, notebook personal computers, and mobile phones. Furthermore, in recent years, research and development of large-sized lithium ion batteries capable of realizing high capacity, high output, and high energy density as batteries for electric vehicles and power storage batteries have been promoted. In particular, in the automobile industry, in order to cope with environmental problems, development of an electric vehicle that uses a motor as a power source and a hybrid vehicle that uses both an engine (internal combustion engine) and a motor as a power source are in progress. . Lithium ion batteries have attracted attention as power sources for such electric vehicles and hybrid vehicles. However, since the lithium ion battery has a high operating voltage and high energy density, sufficient countermeasures against abnormal heat generation due to an internal short circuit or an external short circuit are required.

  Lithium ion batteries include, for example, an electrode winding body in which a positive electrode plate coated with a positive electrode active material, a negative electrode plate coated with a negative electrode active material, and a separator that prevents contact between the positive electrode plate and the negative electrode plate are wound. I have. In the lithium ion battery, the electrode winding body is inserted into the outer can and the electrolyte is injected into the outer can. That is, in a lithium ion battery, a positive electrode plate in which a positive electrode active material is applied to a metal foil and a negative electrode plate in which a negative electrode active material is applied to a metal foil are formed in a band shape, and the positive electrode plate and the negative electrode plate formed in a band shape The electrode winding body is formed by winding in a spiral shape through the separator so that the electrode does not directly contact.

  Thus, the positive electrode plate, the negative electrode plate, and the separator are wound around the axis to form an electrode winding body. However, in a normal lithium ion battery, the positive electrode plate, the negative electrode plate, and the separator are separate components (separate parts). For example, a gap exists between the positive electrode plate and the separator. In the manufacturing process of the lithium ion battery, the positive electrode plate and the negative electrode plate are cut to a predetermined size before forming the above-described wound body, and in addition, the positive electrode and negative electrode current collecting tabs are also connected to the positive electrode plate and the negative electrode plate. Is formed by cutting. Further, after forming the above-described electrode winding body, for example, the positive electrode current collecting tab formed on the positive electrode plate is ultrasonically welded to the positive electrode current collecting ring, or the negative electrode current collecting tab formed on the negative electrode plate is There is a step of ultrasonic welding to the negative electrode current collector ring. Furthermore, the electrode winding body is inserted into an outer can (container), and after injecting electrolyte into the outer can, the outer can and lid are connected by welding or the like to seal the inside of the outer can. There is a process to do.

  Specifically, in the positive electrode current collecting tab and the positive electrode current collecting ring, an aluminum ribbon is wound around the positive electrode current collecting tab, and the positive electrode current collecting tab is connected to the aluminum ribbon by ultrasonic welding. The ultrasonic welding used at this time connects the aluminum ribbon and the positive electrode current collector tab by atomic interdiffusion by rubbing the aluminum ribbon and the positive electrode current collector tab. Therefore, when the positive electrode current collector tab and the aluminum ribbon are connected by ultrasonic welding, there is a high possibility that metal foreign matter (aluminum) is generated due to friction between the aluminum ribbon and the positive electrode current collector tab. The same phenomenon occurs in the connection between the negative electrode current collecting tab and the copper ribbon. That is, when the negative electrode current collector tab and the copper ribbon are connected by ultrasonic welding, there is a high possibility that metal foreign matter (copper) is generated due to friction between the copper ribbon and the negative electrode current collector tab. Furthermore, in welding (arc welding) used in the process of connecting the outer can and the lid, for example, welding scraps are likely to be generated.

From the above, the potential for metal foreign matter to enter the electrode winding body is increased by the steps performed before and after forming the electrode winding body. In particular, in a normal lithium ion battery, since the positive electrode plate, the negative electrode plate, and the separator are composed of separate parts, for example, a gap exists between the positive electrode plate and the separator, and this gap is generated in the manufacturing process described above. It becomes easy for the foreign metal to enter. In this way, when a metal foreign object enters the inside of the electrode winding body, the metal foreign object that has penetrated breaks through the separator, and the positive electrode and the negative electrode are short-circuited by the metal foreign object, for example, metal that has entered the gap between the positive electrode and the separator. When the foreign matter adheres to the positive electrode, a phenomenon occurs in which the attached metal foreign matter is dissolved in the electrolytic solution and then deposited on the negative electrode. When the metal grown by precipitation from the negative electrode reaches the positive electrode, there arises a problem that the positive electrode and the negative electrode are short-circuited.

As described above, the lithium ion battery of the type that forms an electrode winding body that is a normal lithium ion battery has been described. For example, a positive electrode plate coated with a positive electrode active material and a negative electrode plate coated with a negative electrode active material If the lithium ion battery is made of a separator that prevents contact between the positive electrode plate and the negative electrode plate, the positive electrode plate and the negative electrode plate are cut to a predetermined size even in a laminate type lithium ion battery that does not form an electrode winding body. When the metal foreign matter generated by the cutting process for intrudes between the positive electrode plate, the negative electrode plate and the separator, the metal foreign matter breaks through the separator, and the positive electrode and the negative electrode are short-circuited by the metal foreign matter, for example, the gap between the positive electrode and the separator. When the foreign metal intruding into the positive electrode adheres to the positive electrode, a phenomenon occurs in which the adhered foreign metal is dissolved in the electrolytic solution and then deposited on the negative electrode. When the metal grown by precipitation from the negative electrode reaches the positive electrode, there arises a problem that the positive electrode and the negative electrode are short-circuited.

  Therefore, in order to prevent metal foreign matter from entering the gap between the positive electrode plate and the negative electrode plate and the separator and short-circuiting the positive electrode and the negative electrode, the positive electrode plate, the negative electrode plate, and the separator are integrally formed. For example, it is effective to eliminate the gap between the positive electrode and the separator. For example, Patent Document 1 described above describes an example in which the positive electrode plate, the negative electrode plate, and the separator are integrated by directly forming the separator on the positive electrode plate and the negative electrode plate.

  However, in the battery described in Patent Document 1 described above, for example, after drying an electrode plate in which an active material is applied to a metal foil and performing pressure treatment, a slurry separator is applied to the surface of the electrode plate. Then, by drying, a structure in which the electrode plate and the separator are integrated is formed. However, this technique has a problem that the number of processes is large and the manufacturing cost is increased.

  An object of the present invention is to provide a lithium ion battery and a manufacturing technique thereof that can improve reliability by suppressing internal short circuit caused by a metal foreign object and that are excellent in cost.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  The method for producing a lithium ion battery according to the present invention includes: (a) applying a first slurry containing an active material on an electrode plate, and applying a second slurry containing organic particles and inorganic particles on the first slurry. Is provided. (B) After the step (a), the applied first slurry and second slurry are dried to form the active material on the electrode plate, and the organic particles and the active material are formed on the active material. A step of forming a separator containing inorganic particles. Furthermore, (c) after the said (b) process, the process of performing the pressurization process under a heating with respect to the said active material and the said separator is provided.

  In the method of manufacturing a lithium ion battery according to the present invention, (a) a first slurry containing an active material is applied on the first surface of the electrode plate, and a second slurry containing organic particles and inorganic particles on the first slurry. A step of applying a slurry; and (b) after the step (a), the first slurry and the second slurry applied on the first surface are dried to form the first surface of the electrode plate. Forming the active material, and forming a first separator including the organic particles and the inorganic particles on the active material. (C) After the step (b), the first slurry is applied on the second surface of the electrode plate opposite to the first surface, and the second slurry is applied on the first slurry. And (d) after the step (c), the active material is formed on the second surface of the electrode plate by drying the first slurry and the second slurry applied on the second surface. And forming a second separator containing the organic particles and the inorganic particles on the active material. Further, (e) after the step (d), the active material and the first separator formed on the first surface, the active material and the second separator formed on the second surface, A step of applying a pressure treatment under heating.

  In the method of manufacturing a lithium ion battery according to the present invention, (a) a first slurry containing an active material is applied on an electrode plate, a second slurry containing a first material is applied on the first slurry, A step of applying a third slurry containing a second substance different from the first substance on the second slurry is provided. Further, (b) after the step (a), the active material is formed on the electrode plate by drying the applied first slurry, second slurry, and third slurry, and the active material is formed on the active material. Forming a separator including a first insulating film containing the first material and a second insulating film containing the second material. And (c) After the said (b) process, the process which performs the pressurization process under a heating with respect to the said active material and the said separator is provided.

  Further, in the method of manufacturing a lithium ion battery according to the present invention, (a) a first slurry containing an active material is applied on the first surface of the electrode plate, and a second slurry containing the first material is applied on the first slurry. Applying and applying a third slurry containing a second substance different from the first substance on the second slurry. (B) After the step (a), by drying the first slurry, the second slurry, and the third slurry applied on the first surface, on the first surface of the electrode plate Forming the active material, and forming a first separator including a first insulating film containing the first material and a second insulating film containing the second material on the active material. Further, (c) after the step (b), the first slurry is applied on the second surface of the electrode plate opposite to the first surface, and the second slurry is applied on the first slurry. And applying the third slurry onto the second slurry. Next, (d) after the step (c), by drying the first slurry, the second slurry, and the third slurry applied on the second surface, the second surface of the electrode plate Forming the active material, and forming a second separator comprising the first insulating film containing the first material and the second insulating film containing the second material on the active material. Subsequently, (e) after the step (d), the active material and the first separator formed on the first surface, and the active material and the second separator formed on the second surface, And a step of applying a pressure treatment under heating.

  The lithium ion battery according to the present invention includes (a) a positive electrode, (b) a negative electrode, and (c) a separator integrated with one of the positive electrode and the negative electrode, and the separator includes organic particles. The organic particles have an average particle size smaller than the average particle size of the inorganic particles.

  The lithium ion battery according to the present invention includes (a) a positive electrode, (b) a negative electrode, and (c) a separator integrated with one of the positive electrode and the negative electrode. (C1) A first insulating film formed on the electrode, and (c2) a second insulating film formed on the first insulating film.

  Among the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  It is possible to improve the reliability by suppressing the internal short circuit due to the metal foreign matter. In addition, a lithium ion battery excellent in cost can be obtained.

It is a figure which shows the typical structure of a lithium ion battery. It is sectional drawing which shows the internal structure of a cylindrical lithium ion battery. In the technique which this inventor examined, it is a figure which shows the component of the previous step which comprises an electrode winding body. In the technique which this inventor examined, it is a schematic diagram which shows a mode that a positive electrode, a 1st separator, a negative electrode, and a 2nd separator are wound around an axial center, and an electrode winding body is formed. 3 is a cross-sectional view illustrating a configuration of a positive electrode and a negative electrode in Embodiment 1. FIG. 3 is a diagram illustrating a state in which a positive electrode with a separator and a negative electrode are overlapped in Embodiment 1. FIG. It is a figure which shows a mode that the positive electrode with a separator and a negative electrode are wound around an axial center. It is sectional drawing which shows the structure of a 1st modification. It is sectional drawing which shows the structure of a 2nd modification. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 3 is a diagram illustrating an example of a coating apparatus used in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 5 is a diagram showing a manufacturing process of the lithium ion battery in Embodiment 1. FIG. 6 is a diagram showing a configuration of a positive electrode with a separator in Embodiment 2. FIG. 6 is a diagram showing a manufacturing process of a lithium ion battery in Embodiment 2. FIG. 6 is a diagram showing a manufacturing process of a lithium ion battery in Embodiment 2. FIG. 6 is a diagram showing a manufacturing process of a lithium ion battery in Embodiment 2. FIG. 6 is a diagram showing a manufacturing process of a lithium ion battery in Embodiment 2. FIG. 6 is a diagram showing a manufacturing process of a lithium ion battery in Embodiment 2. FIG. 6 is a diagram showing a manufacturing process of a lithium ion battery in Embodiment 2. FIG. 6 is a diagram showing a manufacturing process of a lithium ion battery in Embodiment 2. FIG. 6 is a diagram showing a manufacturing process of a lithium ion battery in Embodiment 2. FIG. 6 is a diagram showing a manufacturing process of a lithium ion battery in Embodiment 2. FIG. 6 is a diagram illustrating a configuration of a separator-attached positive electrode in Embodiment 3. FIG. FIG. 11 is a diagram showing a manufacturing process of the lithium ion battery in the third embodiment. FIG. 11 is a diagram showing a manufacturing process of the lithium ion battery in the third embodiment. FIG. 11 is a diagram showing a manufacturing process of the lithium ion battery in the third embodiment. FIG. 11 is a diagram showing a manufacturing process of the lithium ion battery in the third embodiment. FIG. 11 is a diagram showing a manufacturing process of the lithium ion battery in the third embodiment.

  In the following embodiments, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments. However, unless otherwise specified, they are not irrelevant to each other. There are some or all of the modifications, details, supplementary explanations, and the like.

  Further, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), especially when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and may be more or less than the specific number.

  Further, in the following embodiments, the constituent elements (including element steps and the like) are not necessarily indispensable unless otherwise specified and apparently essential in principle. Needless to say.

  Similarly, in the following embodiments, when referring to the shapes, positional relationships, etc. of the components, etc., unless otherwise specified, and in principle, it is not considered that it is clearly apparent in principle. Including those that are approximate or similar to the shape. The same applies to the above numerical values and ranges.

  In all the drawings for explaining the embodiments, the same members are denoted by the same reference symbols in principle, and the repeated explanation thereof is omitted. In order to make the drawings easy to understand, even a plan view may be hatched.

(Embodiment 1)
<Outline of lithium-ion battery>
Lithium has a redox potential of −3.03 V (vs. NHE), and is the most base metal present on the earth. Since the voltage of the battery is determined by the potential difference between the positive electrode and the negative electrode, the highest electromotive force can be obtained when lithium is used as the negative electrode active material. Further, since the atomic weight of lithium is 6.94 and the density is 0.534 g / cm ³ , both of which are small, the weight per unit amount of electricity is small and the energy density is also high. Therefore, when lithium is used for the negative electrode active material, a small and lightweight battery can be manufactured.

  As described above, lithium is an attractive material as a negative electrode active material of a battery, but problems arise when applied to a chargeable / dischargeable secondary battery. That is, when charging and discharging are repeated in a battery using lithium as a negative electrode, a discharge reaction due to dissolution of lithium and a charge reaction due to precipitation of lithium occur. In this case, repetitive charging causes a lithium precipitation reaction, which causes problems in the performance deterioration and safety of the secondary battery. For example, lithium generated in the charging process reacts with the electrolyte solvent on the active surface, and part of it is consumed for forming a film called SEI (Solid Electrolyte Interface). For this reason, the internal resistance of the battery increases and the discharge efficiency also decreases. In other words, the battery capacity decreases each time the charge / discharge cycle is repeated. Furthermore, when rapidly charged, lithium precipitates in a needle-like / dendritic crystal form (lithium dendrite), which causes various troubles in the secondary battery. For example, lithium dendrite has a large specific surface area, accelerates a decrease in current efficiency due to side reactions, and also has a needle shape, so it may break through the separator and cause an internal short circuit between the positive electrode and the negative electrode. In such a state, the self-discharge is so large that it cannot be used as a battery, or heat generation due to an internal short circuit may cause gas ejection or ignition. From the above, it can be seen that secondary batteries using lithium as the negative electrode have problems in performance degradation and safety.

  Therefore, a new type secondary battery having a principle different from the conventional principle of dissolution and precipitation has been studied. Specifically, a secondary battery using an active material that inserts and releases lithium ions into both the positive electrode and the negative electrode has been studied. In the charging / discharging process of the secondary battery, the phenomenon of dissolution and precipitation of lithium does not occur, and only lithium ions are inserted and desorbed between the electrode active materials. This type of secondary battery is called “rocking chair” type or “shuttle cock” type, and it is stable because lithium ions are only inserted and extracted with repeated charging and discharging. There is the feature that it is. This type of battery will be referred to herein as a lithium ion battery. As described above, in the lithium ion battery, the structure of both the positive electrode and the negative electrode does not change during charging and discharging, and only lithium ions are inserted and desorbed (however, the active material crystal lattice is lithium ion). In addition to the fact that it has an extremely long life cycle characteristic and does not use metallic lithium for the electrode, it has the characteristics that the safety is also dramatically improved.

  Here, a material capable of inserting / extracting lithium ions is used for the active material of the electrode. The conditions required for this active material are as follows. That is, since ions of a finite size called lithium ions are inserted and desorbed, a site (position) where lithium ions should be stored and a channel (path) through which lithium ions can be diffused are required for the active material. Furthermore, electrons need to be introduced into the active material as lithium ions are inserted (occluded).

  Examples of the positive electrode active material that satisfies the above conditions include lithium-containing transition metal oxides. Examples of typical positive electrode active materials include, but are not limited to, lithium cobaltate, lithium nickelate, and lithium manganate. Specifically, the positive electrode active material is a material capable of inserting / extracting lithium, and may be any lithium-containing transition metal oxide in which a sufficient amount of lithium has been previously inserted, and manganese (Mn) as a transition metal , Nickel (Ni), cobalt (Co), iron (Fe) or the like, or a material mainly composed of two or more transition metals. Further, the crystal structure such as the spinel crystal structure and the layered crystal structure is not particularly limited as long as the above-described sites and channels are ensured. Further, a material in which a part of the transition metal or lithium in the crystal is replaced with an element such as Fe, Co, Ni, Cr, Al, Mg, or an element such as Fe, Co, Ni, Cr, Al, Mg in the crystal A material doped with may be used as the positive electrode active material.

  Furthermore, a crystalline carbon material or an amorphous carbon material can be used as the negative electrode active material that satisfies the above-described conditions. However, the negative electrode active material is not limited to these materials. For example, natural graphite, various artificial graphite agents, carbon materials such as coke, and the like may be used. And also in the particle shape, various particle shapes such as a scale shape, a spherical shape, a fiber shape, and a lump shape are applicable.

<Schematic configuration of lithium-ion battery>
Hereinafter, a schematic configuration of the above-described lithium ion battery will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a lithium ion battery. In FIG. 1, the lithium ion battery has an outer can CS, and the outer can CS is filled with an electrolyte EL. In the outer can CS filled with the electrolyte EL, the positive electrode plate PEP and the negative electrode plate NEP are provided to face each other, and the separator SP is provided between the positive electrode plate PEP and the negative electrode plate NEP provided to face each other. Has been placed.

  A positive electrode active material is applied to the positive electrode plate PEP, and a negative electrode active material is applied to the negative electrode plate NEP. For example, the positive electrode active material is formed of a lithium-containing transition metal oxide capable of inserting / extracting lithium ions. FIG. 1 schematically shows that the lithium-containing transition metal oxide is applied to the positive electrode plate PEP. That is, FIG. 1 shows a schematic crystal structure in which oxygen, metal atoms, and lithium are arranged as the lithium-containing transition metal oxide applied to the positive electrode plate PEP. This positive electrode plate PEP and the positive electrode active material constitute a positive electrode.

  On the other hand, for example, the negative electrode active material is formed of a carbon material capable of inserting and removing lithium ions. FIG. 1 schematically shows a state in which this carbon material is applied to the negative electrode plate NEP. That is, FIG. 1 shows a schematic crystal structure in which carbon is arranged as the carbon material applied to the negative electrode plate NEP. The negative electrode is composed of the negative electrode plate NEP and the negative electrode active material.

  The separator SP has a function as a spacer that allows lithium ions to pass through while preventing electrical contact between the positive electrode and the negative electrode. As the separator SP, for example, polyethylene (PE), polypropylene (PP), or a combination of these materials is used as a conventional technique.

A non-aqueous electrolyte is used as the electrolyte EL. The lithium ion battery is a battery that performs charging / discharging by using insertion / extraction of lithium ions in an active material, and lithium ions move in the electrolyte EL. Lithium is a strong reducing agent and reacts violently with water to generate hydrogen gas. Therefore, in a lithium ion battery in which lithium ions move in the electrolytic solution EL, an aqueous solution cannot be used as the electrolytic solution EL unlike a conventional battery. For this reason, in the lithium ion battery, a non-aqueous electrolyte is used as the electrolyte EL. Specifically, as _the electrolyte of the nonaqueous _{electrolyte, LiPF 6, LiClO 4, LiAsF} 6, LiBF 4, LiB (C 6 H 5) 4, CH 3 SO 3 Li, CF 3 SO 3 Li , etc., and mixtures thereof Can be used. Examples of the organic solvent include ethylene carbonate, dimethyl carbonate, propylene carbonate, diethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 1,3-dioxolane, 4-methyl- 1,3 dioxolane, diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propionitrile, etc., or a mixture thereof can be used.

<Mechanism of charge / discharge>
The lithium ion battery is configured as described above, and the charging / discharging mechanism will be described below. First, the charging mechanism will be described. As shown in FIG. 1, when charging a lithium ion battery, a charger CU is connected between the positive electrode and the negative electrode. In this case, in the lithium ion battery, lithium ions inserted in the positive electrode active material are desorbed and released into the electrolyte EL. At this time, the lithium ions are desorbed from the positive electrode active material, whereby electrons flow from the positive electrode to the charger. The lithium ions released into the electrolytic solution EL move through the electrolytic solution EL, pass through the separator SP made of a microporous film, and reach the negative electrode. The lithium ions that have reached the negative electrode are inserted into the negative electrode active material constituting the negative electrode. At this time, when lithium ions are inserted into the negative electrode active material, electrons flow into the negative electrode. In this way, charging is completed as electrons move from the positive electrode to the negative electrode via the charger.

  Next, the discharge mechanism will be described. As shown in FIG. 1, an external load is connected between the positive electrode and the negative electrode. Then, lithium ions inserted in the negative electrode active material are desorbed and released into the electrolyte EL. At this time, electrons are emitted from the negative electrode. The lithium ions released into the electrolytic solution EL move through the electrolytic solution EL, pass through the separator SP made of a microporous film, and reach the positive electrode. The lithium ions reaching the positive electrode are inserted into the positive electrode active material constituting the positive electrode. At this time, when lithium ions are inserted into the positive electrode active material, electrons flow into the positive electrode. In this way, discharge is performed by the movement of electrons from the negative electrode to the positive electrode. In other words, a current can flow from the positive electrode to the negative electrode to drive the load. As described above, in a lithium ion battery, charging / discharging can be performed by inserting / extracting lithium ions between the positive electrode active material and the negative electrode active material.

<Configuration of lithium ion battery>
Next, a configuration example of an actual lithium ion battery LIB will be described. FIG. 2 is a cross-sectional view showing the internal structure of a cylindrical lithium ion battery LIB. As shown in FIG. 2, an electrode winding body WRF including a positive electrode PEL, separators SP1 and SP2, and a negative electrode NEL is formed inside a cylindrical outer can CS having a bottom. Specifically, the electrode winding body WRF is stacked so as to sandwich the separator SP1 (SP2) between the positive electrode PEL and the negative electrode NEL, and is wound around the axis CR in the center of the outer can CS. . The negative electrode NEL is electrically connected to the negative electrode lead plate NT provided at the bottom of the outer can CS, and the positive electrode PEL is electrically connected to the positive electrode lead plate PT provided at the upper portion of the outer can CS. Has been. An electrolyte is injected into the electrode winding body formed inside the outer can CS. The outer can CS is sealed with a battery lid CAP.

  The positive electrode PEL is formed by applying a coating liquid containing a positive electrode active material PAS and a binder (binder) to a positive electrode plate (positive electrode current collector) PEP, drying it, and then pressurizing it. A plurality of rectangular positive electrode current collecting tabs PTAB are formed at the upper end portion of the positive electrode PEL, and the plurality of positive electrode current collecting tabs PTAB are connected to the positive electrode current collecting ring PR. The positive electrode current collection ring PR is electrically connected to the positive electrode lead plate PT. Therefore, the positive electrode PEL is electrically connected to the positive electrode lead plate PT via the positive electrode current collecting tab PTAB and the positive electrode current collecting ring PR. The plurality of positive electrode current collecting tabs PTAB are provided in order to reduce the resistance of the positive electrode PEL and to quickly extract current.

  As the positive electrode active material PAS constituting the positive electrode PEL, for example, the above-described materials represented by lithium cobaltate, lithium nickelate, lithium manganate and the like can be used. As the binder, for example, polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, or the like can be used. Furthermore, for the positive electrode plate, for example, a metal foil or a net-like metal made of a conductive metal such as aluminum is used.

  The negative electrode NEL is formed by applying a coating liquid containing the negative electrode active material NAS and a binder (binder) to the negative electrode plate (negative electrode current collector) NEP and drying it, followed by pressurization. A plurality of rectangular negative electrode current collecting tabs NTAB are formed at the lower end of the negative electrode NEL, and the plurality of negative electrode current collecting tabs NTAB are connected to the negative electrode current collecting ring NR. And this negative electrode current collection ring NR is electrically connected with the negative electrode lead board NT. Therefore, the negative electrode NEL is electrically connected to the negative electrode lead plate NT via the negative electrode current collecting tab NTAB and the negative electrode current collecting ring NR.

  As the negative electrode active material NAS constituting the negative electrode NEL, for example, the above-described materials typified by a carbon material can be used. As the binder, for example, polyvinylidene fluoride, polytetrafluoroethylene, or the like can be used. Furthermore, for the negative electrode plate, for example, a metal foil made of a conductive metal such as copper or a mesh metal is used.

<Problems found by the inventor>
First, the detailed structure of the conventional electrode winding body is demonstrated. FIG. 3 is a diagram showing components in a previous stage constituting the electrode winding body. In FIG. 3, the components constituting the electrode winding body are a positive electrode PEL, a separator SP1, a negative electrode NEL, and a separator SP2. At this time, the positive electrode PEL has a structure in which the positive electrode active material PAS is applied to both surfaces of the positive electrode plate PEP, and the negative electrode NEL has a structure in which the negative electrode active material NAS is applied to both surfaces of the negative electrode plate NEP. . A plurality of rectangular positive electrode current collecting tabs PTAB are formed on the upper side of the positive electrode PEL. Similarly, a plurality of rectangular negative electrode current collecting tabs NTAB are formed on the lower side of the negative electrode NEL. That is, in the prior art, the positive electrode PEL and the negative electrode NEL, and the separator SP1 and the separator SP2 are configured as separate parts (separate bodies).

  Specifically, the configuration of the electrode winding body WRF in the prior art will be described. FIG. 4 is a schematic diagram showing how the electrode wound body WRF is formed by winding the positive electrode PEL, the separator SP1, the negative electrode NEL, and the separator SP2 around the axis CR. As shown in FIG. 4, a separator SP1 which is a separate part is sandwiched between the positive electrode PEL and the negative electrode NEL, and the negative electrode NEL is sandwiched between the separator SP1 and the separator SP2 which are separate parts. And the separator SP2 is wound. At this time, the positive electrode current collecting tab PTAB formed on the positive electrode PEL is arranged on the upper side of the electrode winding body WRF, while the negative electrode current collecting tab (not shown) formed on the negative electrode NEL is wound on the electrode. Located on the lower side of the body WRF. As described above, the electrode winding body WRF in the prior art is configured.

  In a normal lithium ion battery, since the positive electrode plate, the negative electrode plate, and the separator are composed of separate parts (separate bodies), for example, a gap is formed between the positive electrode plate and the separator even after the electrode winding body WRF is formed. Exists. In the manufacturing process of the lithium ion battery, the positive electrode plate and the negative electrode plate are cut to a predetermined size before forming the above-described wound body, and in addition, the positive electrode and negative electrode current collecting tabs are also connected to the positive electrode plate and the negative electrode plate. Is formed by cutting. Furthermore, after forming the electrode winding body, for example, the positive electrode current collecting tab formed on the positive electrode plate is ultrasonically welded to the positive electrode current collecting ring, or the negative electrode current collecting tab formed on the negative electrode plate is There is a process of ultrasonic welding to the electric ring. Furthermore, after the electrode winding body is inserted into an outer can (container) and an electrolyte is injected into the outer can, the outer can and the lid are connected by welding or the like to seal the inside of the outer can. There is a process.

  Specifically, in the positive electrode current collecting tab and the positive electrode current collecting ring, an aluminum ribbon is wound around the positive electrode current collecting tab, and the positive electrode current collecting tab is connected to the aluminum ribbon by ultrasonic welding. The ultrasonic welding used at this time connects the aluminum ribbon and the positive electrode current collector tab by atomic interdiffusion by rubbing the aluminum ribbon and the positive electrode current collector tab. Therefore, when the positive electrode current collector tab and the aluminum ribbon are connected by ultrasonic welding, there is a high possibility that metal foreign matter (aluminum) is generated due to friction between the aluminum ribbon and the positive electrode current collector tab. The same phenomenon occurs in the connection between the negative electrode current collecting tab and the copper ribbon. That is, when the negative electrode current collector tab and the copper ribbon are connected by ultrasonic welding, there is a high possibility that metal foreign matter (copper) is generated due to friction between the copper ribbon and the negative electrode current collector tab. Furthermore, in welding (arc welding) used in the process of connecting the outer can and the lid, for example, welding scraps are likely to be generated.

  From the above, the potential for metal foreign matter to enter the electrode winding body is increased by the steps performed before and after forming the electrode winding body. In particular, in a normal lithium ion battery, since the positive electrode plate, the negative electrode plate, and the separator are composed of separate parts, for example, a gap exists between the positive electrode plate and the separator, and this gap is generated in the manufacturing process described above. There is a problem that the metal foreign matter easily enters.

  When the metal foreign matter generated in this way enters the electrode winding body WRF, an internal short circuit may be caused between the positive electrode and the negative electrode. Specifically, the state in which the metal foreign matter enters the inside of the electrode winding body refers to a metal foreign matter in a gap formed between the positive electrode plate and the separator or a gap formed between the negative electrode plate and the separator. Means a state of intrusion. For example, when the metal foreign matter is copper, if copper that has entered the gap adheres to the positive electrode, the copper is oxidized (electrons are taken away) by the high potential of the positive electrode and is dissolved into the electrolyte as metal ions. When this metal ion reaches the negative electrode, the metal ion is reduced (electrons are supplied) and deposited on the negative electrode as metal (copper). When metal continues to deposit on the negative electrode by such a mechanism, the metal grown from the negative electrode passes through the holes of the separator and reaches the positive electrode, and the positive electrode and the negative electrode are internally short-circuited through the deposited metal. On the other hand, when the metal foreign material is aluminum, no dissolution / precipitation phenomenon occurs due to the oxidation-reduction reaction. However, when the size of the metal foreign material that penetrates increases, the separator breaks through and the positive and negative electrodes are internally short-circuited by the metal foreign material (aluminum). To do. If the positive electrode and the negative electrode are internally short-circuited, it will not function as a lithium ion battery. As described above, in the manufacturing process of the lithium ion battery, there is a possibility that metal foreign matter may be generated, and the generated metal foreign matter is between the gap formed between the positive electrode plate and the separator or between the negative electrode plate and the separator. It can be seen that when entering the formed gap, the positive electrode and the negative electrode may be internally short-circuited.

  Therefore, in the first embodiment, a device that can suppress the internal short circuit caused by the metal foreign matter and improve the reliability of the lithium ion battery is provided. Below, the technical idea in this Embodiment 1 which gave this device is demonstrated.

<Characteristics in Embodiment 1>
The technical idea in the first embodiment is that, for example, when the electrode winding body is formed in a state where the positive electrode and the separator are separate parts, a gap is formed between the positive electrode and the separator, and a metal foreign object enters the gap. By doing so, attention is focused on the potential for the occurrence of an internal short circuit in the lithium ion battery. In consideration of this point of interest, in the first embodiment, even when the electrode winding body is configured, for example, if there is no gap formed between the positive electrode and the separator, the metal foreign matter is removed from the lithium ion battery. This is based on the fact that the reliability of the lithium ion battery can be improved because it can be prevented from entering the inside. Based on the basic idea in the first embodiment, the following features of the first embodiment are conceived. The features of the first embodiment will be described.

  A feature of the first embodiment is that, for example, if the positive electrode and the separator are formed integrally, a gap does not occur between the positive electrode and the separator in the first place, so that a metal foreign object enters between the positive electrode and the separator. This is based on the knowledge that this can be prevented. And in this Embodiment 1, the characteristic of this Embodiment 1 is implement | achieved by embodying this knowledge. That is, the first embodiment is characterized in that, for example, the positive electrode and the separator are integrally formed, and there is no gap between the positive electrode and the separator. In other words, the fact that the positive electrode and the separator are integrated can also mean that the positive electrode and the separator are bonded. Specifically, a configuration in which the positive electrode and the separator are integrally formed will be described with reference to the drawings.

  FIG. 5 is a cross-sectional view showing the configuration of positive electrode PEL and negative electrode NEL in the first embodiment. As shown in FIG. 5, first, the positive electrode PEL has, for example, a positive electrode plate PEP made of aluminum, and a positive electrode active material PAS made of, for example, lithium cobaltate is formed on both surfaces of the positive electrode plate PEP. ing. And separator SP1 and separator SP2 are formed so that it may adhere to positive electrode active material PAS formed in both surfaces of positive electrode plate PEP. That is, in the first embodiment, for example, the separator SP1 is formed so as to adhere to the positive electrode active material PAS formed on the first surface of the positive electrode PEL, and the first surface opposite to the first surface of the positive electrode PEL is formed. A separator SP2 that adheres to the positive electrode active material PAS formed on the two surfaces is formed. Thus, in Embodiment 1, the positive electrode PEL made of the positive electrode plate PEP and the positive electrode active material PAS, the separator SP1 and the separator SP2 are integrally formed. Therefore, according to the first embodiment, since there is no gap between the positive electrode PEL and the separator SP1, or between the positive electrode PEL and the separator SP2, it is possible to prevent intrusion of metal foreign matters attached to the positive electrode PEL. Can do. As a result, it is possible to prevent an internal short circuit in the lithium ion battery due to the metal foreign matter, thereby improving the reliability of the lithium ion battery.

  On the other hand, as shown in FIG. 5, the negative electrode NEL has a structure in which, for example, a negative electrode active material NAS made of, for example, a carbon material (carbon material) is formed on both surfaces of a negative electrode plate NEP made of copper. In this way, the positive electrode PEL with the separator SP1 (SP2) and the negative electrode NEL in the first embodiment are configured.

  For example, in the prior art shown in FIG. 3, since the positive electrode PEL, the separator SP1, the separator SP2, and the negative electrode NEL are configured as separate parts (separate bodies), as shown in FIG. When formed, a gap is always generated between the positive electrode PEL and the separator SP1 (separator SP2). As a result, in the prior art, the potential for metal foreign matter generated by ultrasonic welding or arc welding performed in the subsequent assembly process to enter the gap is increased. And when a metal foreign material penetrate | invades into the clearance gap formed between positive electrode PEL and separator SP1 (separator SP2), the internal short circuit of the lithium ion battery resulting from a metal foreign material will arise, and the reliability of a lithium ion battery falls. Resulting in.

  On the other hand, in the first embodiment, as shown in FIG. 5, the positive electrode PEL, the separator SP1, and the separator SP2 are integrally formed. In other words, the positive electrode PEL and the separator SP1 or the positive electrode PEL and the separator SP2 are bonded. For this reason, there is no room for gaps between the positive electrode PEL and the separator SP1 and between the positive electrode PEL and the separator SP2. Therefore, according to the first embodiment, since there is no gap between the positive electrode PEL and the separator SP1, or between the positive electrode PEL and the separator SP2, it is possible to prevent intrusion of metal foreign matters attached to the positive electrode PEL. Can do. As a result, it is possible to prevent an internal short circuit in the lithium ion battery due to the metal foreign matter, thereby improving the reliability of the lithium ion battery.

  Specifically, the state in which the positive electrode PEL with the separator SP1 (SP2) and the negative electrode NEL in Embodiment 1 are wound to form the electrode winding body WRF will be described. FIG. 6 shows a state in which the positive electrode PEL with separator SP1 (SP2) and the negative electrode NEL in Embodiment 1 are overlapped. Then, in such a state where the positive electrode PEL with the separator SP1 (SP2) and the negative electrode NEL are overlapped with each other, as shown in FIG. 7, the positive electrode PEL with the separator SP1 (SP2) and the negative electrode NEL are arranged around the axis CR.捲. At this time, as shown in FIG. 7, since the separator SP1 and the separator SP2 are adhered to both surfaces of the positive electrode PEL, even after the electrode winding body WRF is formed, between the positive electrode PEL and the separator SP1, or It can be seen that no gap is formed between the positive electrode PEL and the separator SP2.

  Here, an important point in the first embodiment is that the positive electrode PEL, the separator SP1, and the separator SP2 are integrally formed. That is, in the first embodiment, the separator SP1 and the separator SP2 are configured to adhere to both surfaces of the positive electrode PEL, so that no gap is generated between the positive electrode PEL and the separator SP1 or between the positive electrode PEL and the separator SP2. I am doing so. The reason why the positive electrode PEL, the separator SP1, and the separator SP2 are integrally formed is as follows. That is, as described in the section of the problem newly found by the present inventor, when a metal foreign matter such as copper adheres to the positive electrode PEL, for example, the metal foreign matter attached to the positive electrode PEL is dissolved in the electrolytic solution and electrolysis is performed. Metal foreign matter dissolved in the liquid is deposited on the negative electrode NEL. If this phenomenon continues, the metal foreign matter deposited on the negative electrode NEL reaches the positive electrode PEL, causing an internal short circuit between the positive electrode PEL and the negative electrode NEL. Therefore, the internal short circuit of the lithium ion battery due to the dissolution / precipitation mechanism of the metallic foreign matter is caused by the metallic foreign matter adhering to the positive electrode PEL. This indicates that it is important to prevent the metallic foreign matter from adhering to the positive electrode PEL in order to effectively suppress the internal short circuit of the lithium ion battery due to the dissolution / precipitation mechanism of the metallic foreign matter. Therefore, in the first embodiment, the positive electrode PEL, the separator SP1, and the separator SP2 are integrally formed. According to this configuration, since there is no gap between the positive electrode PEL and the separator SP1, or between the positive electrode PEL and the separator SP2, it is possible to prevent metal foreign matter from entering through the gap and adhering to the positive electrode PEL. That is, in the first embodiment, it is made from the viewpoint of preventing dissolution / precipitation of a metallic foreign material, which is considered as a cause of causing an internal short circuit of the lithium ion battery. The positive electrode PEL, the separator SP1, and the separator SP2 are used. As a result, the internal short circuit of the lithium ion battery due to the dissolution / precipitation of the metal foreign matter can be effectively prevented.

  However, according to the characteristic configuration in the first embodiment, since the gap can be eliminated, not only the internal short circuit of the lithium ion battery due to the dissolution / precipitation of the metal foreign matter can be prevented, but also the entry of the large metal foreign matter itself can be prevented. This can also prevent a short circuit between the positive electrode PEL and the negative electrode NEL due to the large metal foreign substance itself breaking through the separator SP1 (SP2). That is, the characteristic configuration of the first embodiment in which the positive electrode PEL and the separator SP1 and the separator SP2 are integrally formed can prevent the internal short circuit of the lithium ion battery due to the mechanism of dissolution / precipitation of the metal foreign matter, It is also possible to prevent internal short-circuiting of the lithium ion battery due to large metal foreign matter directly breaking through the separator SP1 (SP2). In other words, according to the characteristic configuration of the first embodiment, the separator SP1 (SP2) mainly with the large metal foreign material is directly connected mainly from the internal short circuit due to the dissolution / precipitation phenomenon due to the small metal foreign material. It is possible to effectively prevent an internal short circuit due to a different mechanism of internal short circuit due to breakthrough. That is, according to the feature in the first embodiment, it is possible to prevent the internal short circuit of the lithium ion battery widely from the internal short circuit due to the small metal foreign object to the internal short circuit due to the large metal foreign object. The reliability of the ion battery can be improved sufficiently.

  As described above, according to the configuration of the first embodiment, the positive electrode PEL, the separator SP1, and the separator SP2 are integrally formed. As a result, the internal short circuit of the lithium ion battery can be suppressed. However, in the first embodiment, a safety measure is taken to stop thermal runaway even if an internal short circuit occurs in the lithium ion battery. ing. That is, in the first embodiment, a means for sufficiently suppressing the occurrence of an internal short circuit in the lithium ion battery and suppressing thermal runaway even if an internal short circuit occurs is provided. Below, the point for ensuring this safety is demonstrated.

A further feature of the first embodiment resides in materials used for the separator SP1 and the separator SP2. That is, the material of the separator SP1 and the separator SP2 used in the first embodiment is different from the material in the prior art. This is because, in the first embodiment, as described later, the manufacturing process of the separator SP1 and the separator SP2 is different from that of the prior art, and it is necessary to bond the separator SP1 or separator SP2 and the positive electrode PEL. That is, the separator in the prior art is configured as a component (separate) from the positive electrode PEL and is not bonded to the positive electrode PEL, whereas the separator SP1 (SP2) in the first embodiment is used. ) Is integrally formed by adhering to the positive electrode PEL. Specifically, the separator SP1 (SP2) in the first embodiment can be made of, for example, a material including a binder (binder), a ceramic that is an insulating material, and an organic material. Examples of the ceramic at this time include alumina (Al ₂ O ₃ ) and silica (SiO ₂ ). Thereby, the heat resistance of separator SP1 (SP2) can be improved. Examples of the organic material include polyolefin resins typified by high-density polyethylene (melting point: 130 ° C. to 137 ° C.) and linear low-density polyethylene (melting point: 122 ° C. to 124 ° C.).

  In particular, the first embodiment is characterized in that the constituent material of the separator SP1 (SP2) formed integrally with the positive electrode PEL includes an organic material having a melting point lower than that of the inorganic material (ceramic). . That is, in the first embodiment, the separator SP1 (SP2) includes an organic material typified by a polyolefin resin. This organic material also has the function of preventing abnormal current due to a short circuit of the battery, rapid internal pressure and temperature rise, and ignition. In other words, the separator SP1 (SP2) in the first embodiment serves as a thermal fuse for preventing electrical contact between the positive electrode and the negative electrode and allowing lithium ions to pass therethrough, as well as preventing short circuit and overcharge. It has a function. The shutdown function of this organic material can maintain the safety of the lithium ion battery. For example, when a lithium ion battery causes an external short circuit for some reason, a large current flows instantaneously, and the temperature may rise abnormally due to Joule heat. At this time, when the separator SP1 (SP2) contains an organic material having a melting point lower than that of the ceramic, an organic material having a melting point lower than that of the ceramic melts even if an abnormal temperature rise occurs due to a short circuit. Since the vacancies (micropores) close in the vicinity of the melting point, it is possible to prevent the transmission of lithium ions between the positive electrode and the negative electrode. In other words, when the separator SP1 (SP2) contains an organic material having a melting point lower than that of the ceramic, current can be interrupted at the time of an external short circuit, and the temperature rise inside the lithium ion battery can be stopped. That is, according to the first embodiment, the separator SP1 (SP2) is configured to include both ceramic (inorganic material) and an organic material having a melting point lower than that of the ceramic, so that the heat resistance is excellent. It is possible to provide a shutdown function that cuts off an abnormal current during a short circuit. As a result, according to the first embodiment, it is possible to provide a lithium ion battery with high safety and excellent reliability.

  At this time, in Embodiment 1, it is desirable that the average particle diameter of the organic particles constituting the organic material is smaller than the average particle diameter of the inorganic particles constituting the inorganic material (ceramic). The reason is that the average particle size of the organic particles constituting the organic material is reduced, which means that the organic particles are densely packed. As a result, when the organic particles melt, This is because it is easy to block, and the shutdown function by the organic particles can be sufficiently exhibited. Specifically, for example, the average particle diameter of the organic particles is 1 μm, and the average particle diameter of the inorganic particles is 4 μm.

  Here, the particle size of the organic particles and inorganic particles can be measured by using, for example, a laser diffraction / scattering method. This laser diffraction / scattering method is a measurement method utilizing the fact that when a particle is irradiated with a laser beam, diffraction scattered light is generated from the particle. At this time, the light intensity distribution of the diffracted and scattered light is different for each particle size, and therefore the particle size distribution can be measured by detecting and analyzing the light intensity distribution of the diffracted and scattered light. The average particle size is defined as the particle size in which the large particle size region and the small particle size region are equal when the particle size distribution of the powder (particles) is divided into two regions with a certain particle size as a boundary. Is done. This average particle diameter is generally called “d50”.

  As described above, according to the first embodiment, since the separator SP1 and the separator SP2 are bonded and integrated on both surfaces of the positive electrode PEL, the positive electrode PEL and the separator SP1 or the positive electrode A gap generated between the PEL and the separator SP2 can be eliminated. As a result, it is possible to prevent an internal short circuit in the lithium ion battery due to the metal foreign matter, thereby improving the reliability of the lithium ion battery.

  And according to the lithium ion battery in this Embodiment 1, since the internal short circuit resulting from the metal foreign material which generate | occur | produces during a manufacturing process (assembly process) can be suppressed, the manufacturing yield of a lithium ion battery is improved. Can do. As a result, according to the first embodiment, the cost of the lithium ion battery can be reduced. In particular, in the first embodiment, in addition to the effect of cost reduction by improving the manufacturing yield, the cost of the lithium ion battery can be reduced from the viewpoint that it is not necessary to prepare a separator as a separate part. For example, in a conventional lithium ion battery, since the cost of a separator which is a separate part is high, it has been difficult to reduce the cost of the lithium ion battery. In Embodiment 1, a separator which is a separate part is prepared. This eliminates the need to perform the process and eliminates the need for a facility for manufacturing a separate separator, which can greatly reduce the cost of the lithium ion battery. That is, as will be described later, in the first embodiment, since the positive electrode PEL and the separator SP1 (SP2) are integrally formed, the process of manufacturing the positive electrode PEL only needs to be slightly changed, and the separator SP1 (SP2) itself Since there is no need to provide facilities for manufacturing the battery, the cost of the lithium ion battery can be reduced.

  Furthermore, in this Embodiment 1, separator SP1 (SP2) is comprised so that the organic material with a melting | fusing point lower than an inorganic material and an inorganic material may be included. Thereby, according to this Embodiment 1, separator SP1 (SP2) which has the shutdown function which interrupts | blocks the abnormal current at the time of a short circuit can be provided, being excellent in heat resistance. As a result, according to the first embodiment, it is possible to provide a lithium ion battery with high safety and excellent reliability.

  In the first embodiment, in particular, the internal short circuit of the lithium ion battery due to the mechanism of dissolution / precipitation of the metallic foreign material and the internal short circuit of the lithium ion battery caused by the large metallic foreign material directly breaking through the separator SP1 (SP2). From the standpoint of preventing both, the positive electrode PEL, the separator SP1, and the separator SP2 are integrally formed. However, the technical idea of the first embodiment is not limited to this. In other words, the technical idea of the first embodiment is to eliminate the gap, and to eliminate the gap to prevent the metal foreign matter from entering the lithium ion battery. For this reason, it is not always necessary to form the positive electrode PEL, the separator SP1, and the separator SP2 integrally as in the first embodiment described above, and another configuration example in which a gap is eliminated can be considered. Hereinafter, this modification will be described.

<Modification in Embodiment 1>
FIG. 8 is a cross-sectional view showing the configuration of the first modification. In FIG. 8, the difference from the first embodiment is that in the first modification, the negative electrode NEL, the separator SP1 and the separator SP2 are integrally formed. Specifically, the negative electrode NEL has, for example, a negative electrode plate NEP made of copper, and a negative electrode active material NAS made of, for example, a carbon material (carbon material) is formed on both surfaces of the negative electrode plate NEP. . The separator SP1 and the separator SP2 are formed so as to adhere to the negative electrode active material NAS formed on both surfaces of the negative electrode plate NEP. That is, in the first modification, for example, the separator SP1 is formed on the first surface of the negative electrode NEL so as to adhere to the negative electrode active material NAS, and the second surface opposite to the first surface of the negative electrode NEL is formed. A separator SP2 that adheres to the negative electrode active material NAS is formed. Thus, in the first modified example, the negative electrode plate NEP and the negative electrode NEL made of the negative electrode active material NAS, the separator SP1 and the separator SP2 are integrally formed. Therefore, according to the first modification, since there is no gap between the negative electrode NEL and the separator SP1, or between the negative electrode NEL and the separator SP2, it is possible to prevent the intrusion of metal foreign matters attached to the negative electrode NEL. Can do. As a result, it is possible to prevent an internal short circuit in the lithium ion battery due to the metal foreign matter, thereby improving the reliability of the lithium ion battery. Furthermore, since the separator SP1 (SP2) is configured to include an organic material having a melting point lower than that of the inorganic material and the inorganic material as in the first embodiment, the safety due to the shutdown function is high. A lithium ion battery with excellent reliability can be provided.

  On the other hand, as shown in FIG. 8, the positive electrode PEL has a structure in which, for example, a positive electrode active material PAS made of, for example, lithium cobaltate is formed on both surfaces of a positive electrode plate PEP made of aluminum. In this way, the negative electrode NEL with the separator SP1 (SP2) and the positive electrode PEL in the first modified example are configured.

  Subsequently, FIG. 9 is a cross-sectional view illustrating a configuration of a second modification. In FIG. 9, the difference from the first embodiment is that in the second modification, the separator SP1 is bonded and integrated on one side of the positive electrode PEL, and the separator SP2 is bonded on one side of the negative electrode NEL. It is an integrated point. Specifically, as shown in FIG. 9, the positive electrode PEL has the positive electrode active material PAS formed on both surfaces of the positive electrode plate PEP, and the separator SP1 is adhered to the positive electrode active material PAS formed on one surface. Is formed. On the other hand, in the negative electrode NEL, the negative electrode active material NAS is formed on both surfaces of the negative electrode plate NEP, and the separator SP2 is formed so as to adhere to the negative electrode active material NAS formed on one surface. Also in the second modified example configured as described above, a gap can be eliminated between the positive electrode PEL and the separator SP1, or between the negative electrode NEL and the separator SP2, so that the lithium ion battery can be connected to the inside. Intrusion of metallic foreign matter can be prevented. As a result, it is possible to prevent an internal short circuit in the lithium ion battery due to the metal foreign matter, thereby improving the reliability of the lithium ion battery. Furthermore, since the separator SP1 (SP2) is configured to include an organic material having a melting point lower than that of the inorganic material and the inorganic material as in the first embodiment, the safety due to the shutdown function is high. A lithium ion battery with excellent reliability can be provided.

<Method for Manufacturing Lithium Ion Battery in Embodiment 1>
The lithium ion battery in the first embodiment is configured as described above, and the manufacturing method thereof will be described below with reference to the drawings.

  First, a process of forming the positive electrode PEL with the separator SP1 (SP2), which is a feature of the first embodiment, will be described. As shown in FIG. 10, for example, a positive electrode active material PAS made of lithium cobalt oxide and carbon as a conductive additive are mixed. Then, as shown in FIG. 11, for example, a solution in which a binder (binder) made of polyvinylidene fluoride is dissolved in N-methylpyrrolidone (NMP) is formed, and the positive electrode active material PAS and the conductive auxiliary agent are added to this solution. The slurry SL1 is prepared by kneading.

Similarly, as shown in FIG. 12, for example, ceramic powder CRS (particle size is, for example, 4 μm) such as alumina (Al ₂ O ₃ ) or silica (SiO ₂ ), for example, high-density polyethylene (melting point: 130 to 137 ° C.) or linear low density polyethylene (melting point: 122 to 124 ° C.) or the like, and an organic material OM (particle size is, for example, 1 μm) made of a polyolefin resin. Then, as shown in FIG. 13, for example, a solution in which a binder (binder) made of polyvinylidene fluoride is dissolved in N-methylpyrrolidone (NMP) is formed, and ceramic powder CRS and organic material OM are added to this solution. The slurry SL2 is prepared by kneading.

  Then, as shown in FIG. 14, slurry SL1 containing positive electrode active material PAS and a binder (binder) is apply | coated to positive electrode plate (positive electrode collector) PEP. Specifically, as shown in FIG. 15, for example, a die coater DC is used to apply a slurry SL1 containing a positive electrode active material PAS (including a conductive additive) on a positive electrode plate PEP made of aluminum.

  Subsequently, as shown in FIG. 16, the slurry SL2 obtained by kneading the ceramic powder CRS and the organic material OM is applied onto the slurry SL1 containing the positive electrode active material PAS applied to the positive electrode plate PEP. Specifically, as shown in FIG. 17, slurry SL2 in which ceramic powder CRS and organic material OM are kneaded on slurry SL1 containing positive electrode active material PAS applied to positive electrode plate PEP using die coater DC. Apply. Here, first, a slurry SL1 in which the positive electrode active material PAS is kneaded is applied onto the positive electrode plate PEP using the die coater DC, and then a slurry in which the ceramic powder CRS and the organic material OM are kneaded on the slurry SL1. The sequential application method for applying SL2 has been described. For example, a slurry SL1 in which the positive electrode active material PAS is kneaded on the positive electrode plate PEP and a slurry SL2 in which the ceramic powder CRS and the organic material OM are kneaded are combined with the die coater DC. It is also possible to use a simultaneous coating method in which the coating is simultaneously performed on the positive electrode plate PEP.

  Specifically, the batch application process of the slurry SL1 and the slurry SL2 is performed by, for example, an application apparatus illustrated in FIG. FIG. 18 is a schematic diagram illustrating an example of a coating apparatus used in the first embodiment. In FIG. 18, the coating apparatus has, for example, a rotatable roller RL1, and a positive electrode plate PEP is disposed on the surface of this roller RL1. A die coater DC1 and a die coater DC2 are disposed on the positive electrode plate PEP disposed on the surface of the roller RL1. The die coater DC1 is connected to, for example, a tank in which the slurry SL1 is stored via the supply pump PMP1, and the slurry SL1 stored in the tank flows into the die coater DC1 by the supply pump PMP1, and the die coater DC1 The slurry SL1 is applied on the positive electrode plate PEP. Similarly, the die coater DC2 is connected to, for example, a tank in which the slurry SL2 is stored via the supply pump PMP2, and the slurry SL2 stored in the tank flows into the die coater DC2 by the supply pump PMP2. The slurry SL2 is applied from the die coater DC2 onto the positive electrode plate PEP. By using the coating apparatus configured as described above, first, the slurry SL1 can be applied onto the positive electrode plate PEP, and the slurry SL2 can be applied onto the slurry SL1.

  Next, as shown in FIG. 19, the slurry containing the positive electrode active material PAS applied to the positive electrode plate PEP and the slurry containing the ceramic powder CRS and the organic material OM are dried. Specifically, for example, by heating the positive electrode plate PEP at 120 ° C. or lower, the slurry SL1 and the slurry SL2 applied on the positive electrode plate PEP are dried. The heat treatment here needs to be set to a temperature at which the organic material OM contained in the slurry SL2 does not melt. By drying slurry SL1 and slurry SL2 as described above, positive electrode active material PAS is formed on positive electrode plate PEP, and a mixture of ceramic powder CRS and organic material OM is formed on this positive electrode active material PAS. can do.

  Then, after the positive electrode active material PAS applied to one surface (first surface) of the positive electrode plate PEP and the mixture containing the ceramic powder CRS and the organic material OM are dried, as shown in FIG. 20, the positive electrode plate PEP The other surface (second surface) of slurry SL1 in which positive electrode active material PAS is kneaded and slurry SL2 in which ceramic powder CRS and organic material OM are kneaded are applied.

  Thereafter, as shown in FIG. 21, for example, by heating the positive electrode plate PEP at 120 ° C. or lower, the slurry SL1 and the slurry SL2 applied to the other surface of the positive electrode plate PEP are dried, and the positive electrode plate PEP A positive electrode active material PAS and a mixture of ceramic powder CRS and organic material OM are formed on both sides.

  Subsequently, as shown in FIG. 22, a heating / pressurizing process using a roller RL is performed on the positive electrode plate PEP. This heating / pressurizing process is performed at 120 ° C. or less, for example. Thereby, it is possible to increase the density of the positive electrode active material PAS applied to the positive electrode plate PEP. Thus, according to the first embodiment, as shown in FIG. 23, the positive electrode active material PAS is formed on the positive electrode plate PEP, and the ceramic powder CRS and the organic material OM are formed on the positive electrode active material PAS. Separator SP1 and separator SP2 containing can be formed.

  According to the first embodiment, the separator SP1 (SP2) and the positive electrode can be integrally formed by performing a drying process and a pressurizing process all at once, so that the number of steps can be reduced and the manufacturing cost can be reduced. It is done. Further, according to the first embodiment, since the separator SP1 (SP2) is configured to include the ceramic powder CRS and the organic material OM, it has excellent heat resistance and has a shutdown function. According to the first embodiment, a highly safe lithium ion battery can be manufactured. Furthermore, according to the first embodiment, since the separator SP1 (SP2) and the positive electrode are integrally formed, the gap between the separator SP1 (SP2) and the positive electrode can be eliminated, so that the entry of metal foreign matter can be prevented. Can be prevented. Therefore, an internal short circuit can be prevented, and a highly reliable lithium ion battery can be manufactured.

  Subsequently, a process of forming the negative electrode NEL will be described. As shown in FIG. 24, for example, a negative electrode active material NAS made of a carbon material (carbon material) is produced. Then, as shown in FIG. 25, for example, a solution in which a binder (binder) made of polyvinylidene fluoride is dissolved in N-methylpyrrolidone (NMP) is formed, and the negative electrode active material NAS is kneaded with this solution to form a slurry. SL3 is produced.

  Thereafter, as shown in FIG. 26, a slurry SL3 containing a negative electrode active material NAS and a binder (binder) is applied to a negative electrode plate (negative electrode current collector) NEP. Specifically, as shown in FIG. 26, the negative electrode active material NAS is applied onto the negative electrode plate NEP made of copper, for example, using a die coater. Then, the negative electrode active material NAS applied to the negative electrode plate NEP is dried. Specifically, for example, the negative electrode active material NAS applied on the negative electrode plate NEP is dried by heating the negative electrode plate NEP at 120 ° C. or lower.

  Then, after the negative electrode active material NAS applied to one surface of the negative electrode plate NEP is dried, the slurry SL3 in which the negative electrode active material NAS is kneaded is applied to the other surface of the negative electrode plate NEP. Thereafter, the negative electrode active material NAS applied to the other surface of the negative electrode plate NEP is dried by, for example, heating the negative electrode plate NEP at 120 ° C. or lower.

  In this manner, as shown in FIG. 27, after the negative electrode active material NAS is formed on both surfaces of the negative electrode plate NEP, the negative electrode plate NEP is subjected to a heating / pressurizing process. This heating / pressurizing process is performed at 120 ° C. or less, for example. Thereby, it is possible to increase the density of the negative electrode active material NAS applied to the negative electrode plate NEP. As described above, the negative electrode plate NEP can be formed.

  Subsequently, as shown in FIG. 28, the positive electrode plate PEP coated with the separator SP1 (SP2) and the positive electrode active material PAS is cut and processed. Thereby, a plurality of positive electrode current collecting tabs PTAB having a rectangular shape on one side (upper side) of the positive electrode plate PEP can be formed. In this way, the positive electrode PEL processed integrally with the separator SP1 (SP2) can be formed.

  Similarly, the negative electrode plate NEP coated with the negative electrode active material NAS is cut and processed. Accordingly, a plurality of negative electrode current collecting tabs NTAB having a rectangular shape on one side (lower side) of the negative electrode plate NEP can be formed. Thus, as shown in FIG. 29, the negative electrode NEL processed by applying the negative electrode active material NAS to the negative electrode plate NEP can be formed.

  Next, as shown in FIG. 30, the positive electrode PEL formed integrally with the separator SP1 (SP2 (not shown)) and the negative electrode NEL are overlapped. At this time, the positive electrode current collecting tab PTAB formed in the positive electrode PEL and the negative electrode current collecting tab NTAB formed in the negative electrode NEL are arranged in opposite directions.

  Then, as shown in FIG. 31, the electrode wound body WRF is formed by winding the positive electrode PEL with the separator SP1 (SP2) and the negative electrode NEL around the shaft CR in a state where the negative electrode NEL is overlapped. In this way, the electrode winding body WRF can be formed.

  Subsequently, as shown in FIG. 32, the positive electrode current collecting tab PTAB protruding from the upper end portion of the electrode winding body WRF is connected to the positive electrode current collecting ring PR. Similarly, the negative electrode current collecting tab NTAB protruding from the lower end of the electrode winding body WRF is connected to the negative electrode current collecting ring NR. Here, the connection of the positive electrode current collector tab PTAB to the positive electrode current collector ring PR and the connection of the negative electrode current collector tab NTAB to the negative electrode current collector ring NR are performed by, for example, ultrasonic welding. For this reason, when the positive electrode PEL and the separator SP1 (SP2) are separated and configured, there is a gap between the positive electrode PEL and the separator SP1 (SP2). There is a possibility that the metal foreign matter is scattered at the time of welding, and the metal foreign matter enters the gap formed between the positive electrode PEL and the separator SP1 (SP2). On the other hand, in the first embodiment, since the positive electrode PEL and the separator SP1 (SP2) are integrally formed and there is no gap, the metal foreign matter generated during ultrasonic welding enters the electrode winding body WRF. Thus, adhesion to the positive electrode PEL can be prevented.

  Next, as shown in FIG. 33, the electrode winding body WRF is inserted into the outer can CS. Then, as shown in FIG. 34, the outer can CS is processed to form the groove DT. The groove DT is provided to fix the electrode winding body WRF inserted in the outer can CS so as not to move in the vertical direction.

  And as shown in FIG. 35, electrolyte EL is inject | poured into the exterior can CS which inserted the electrode winding body WRF. Then, the lithium ion battery in this Embodiment 1 can be manufactured by sealing the upper part of the armored can CS with a cap.

<Advantage of Lithium Ion Battery Manufacturing Method in Embodiment 1>
For example, as a manufacturing technique for integrally forming a positive electrode and a separator, a positive electrode active material is dried and subjected to a pressure treatment, and then a separator material ( A technique for applying a slurry) is conceivable. In the case of this technique, there is an advantage that the integration of the positive electrode and the separator can be realized relatively easily. Such a manufacturing technique is sometimes called a wet-on-dry method because a slurry-like separator material is applied onto the dried positive electrode active material.

  In the above-described wet-on-dry method, for example, a step of applying a slurry containing an electrode material and a step of applying a slurry containing a separator material are separate, and therefore there are a plurality of application steps. That is, in the wet-on-dry method, after applying a slurry containing an electrode material, the slurry is dried and pressure treatment is performed on the dried electrode material. The steps so far can be performed by conventional manufacturing equipment for manufacturing a positive electrode. Thereafter, since there is a step of applying a separator material on the formed electrode material, new manufacturing equipment for applying and drying the separator material is required in addition to the conventional manufacturing equipment for manufacturing the positive electrode. For this reason, there are problems in that the manufacturing process of the lithium ion battery becomes long and sufficient cost reduction cannot be achieved. In other words, the wet-on-dry method is a technology with an emphasis on manufacturability, and it can be said that there is room for improvement from the viewpoint of further promoting cost reduction.

  On the other hand, according to the manufacturing method of the lithium ion battery in this Embodiment 1, the electrode material (positive electrode active material) and the separator material (ceramic and organic material) are collectively apply | coated on the positive electrode plate. Therefore, further cost reduction can be achieved as compared with the wet-on-dry method in which the electrode material and the separator material are separately applied. That is, in the method for manufacturing a lithium ion battery according to the first embodiment, after the slurry-like electrode material and the slurry-state separator material are applied together, the slurry-state electrode material and the slurry-state separator material are combined. Batch drying is performed, and then the dried electrode material and separator material are collectively pressed. From this, according to the manufacturing method of the lithium ion battery in this Embodiment 1, the separator material can also be formed on an electrode material, applying the manufacturing facility of the positive electrode which exists conventionally. From this, it is not necessary to newly provide another manufacturing facility only for applying the separator material, and therefore the cost can be sufficiently reduced. That is, in the manufacturing method of the lithium ion battery according to the first embodiment, the electrode material and separator material can be collectively applied, collectively dried, and collectively pressurized by using the electrode production line as it is. There is an advantage that the cost can be reduced. In addition, the manufacturing method of the lithium ion battery according to the first embodiment focusing on the cost reduction is sometimes referred to as a wet-on-wet method because a slurry separator material is applied onto a slurry electrode material.

(Embodiment 2)
<Characteristics of Embodiment 2>
In the first embodiment, the lithium ion battery in which the separator including the organic material and the inorganic material and the positive electrode are integrated has been described. In the second embodiment, the positive electrode and the separator are integrated, and the separator is used. An example in which a first insulating film containing an inorganic material (inorganic insulating film) and a second insulating film containing an organic material (organic insulating film) are stacked is described.

  FIG. 36 is a cross-sectional view showing an integrated structure of the separator and the positive electrode in the second embodiment. As shown in FIG. 36, in the integrated structure of the separator and the positive electrode in the second embodiment, the positive electrode active material PAS is formed on both surfaces of the positive electrode plate PEP, so that the positive electrode active material PAS is in direct contact with the positive electrode active material PAS. For example, an insulating film IF1 containing an inorganic material such as ceramic powder CRS (alumina or silica) is formed. An insulating film IF2 containing an organic material OM such as polyolefin resin is formed so as to be in direct contact with the insulating film IF1. That is, in the second embodiment, the separator SP1 (SP2) is formed from the laminated film of the insulating film IF1 and the insulating film IF2. The advantages of this configuration will be described below.

  For example, as in the first embodiment, it is conceivable to configure the separator SP1 (SP2) so as to include an inorganic material and an organic material together. In this case, when the separator SP1 (SP2) contains an organic material having a melting point lower than that of the ceramic, the organic material having a melting point lower than that of the ceramic melts even if an abnormal temperature rise occurs due to a short circuit. Since the vacancies (micropores) close in the vicinity of the melting point, it is possible to prevent transmission of lithium ions between the positive electrode and the negative electrode. In other words, when the separator SP1 (SP2) contains an organic material having a melting point lower than that of the ceramic, current can be interrupted at the time of an external short circuit, and the temperature rise inside the lithium ion battery can be stopped. That is, as in the first embodiment, the separator SP1 (SP2) is configured to include both a ceramic (inorganic material) and an organic material having a melting point lower than that of the ceramic, thereby providing a short circuit while being excellent in heat resistance. It is possible to provide a shutdown function that cuts off abnormal current at the time. As a result, according to the first embodiment, a lithium ion battery having high safety and excellent reliability can be provided.

  However, when the separator SP1 (SP2) actually including an inorganic material and an organic material is formed, the organic material may be unevenly distributed in the separator SP1 (SP2). As described above, when the organic material is unevenly distributed in the separator SP1 (SP2), the pores (micropores) are blocked due to the uneven distribution of the organic material in the separator SP1 (SP2) during abnormal heat generation in the lithium ion battery. Defects may occur. That is, when the organic material is unevenly distributed, it means that there are a region where a large amount of organic material is present and a region where a small amount is present in the separator SP1 (SP2). In a region where the organic material is small, even if the organic material is melted, the absolute amount is small, so that a large number of holes cannot be filled. As a result, when abnormal heat is generated, there is a high possibility that the electrode reaction may be interrupted and the shutdown function due to melting of the organic material cannot be fully exhibited.

  In contrast, in the second embodiment, the separator SP1 (SP2) is formed from a laminated film of the insulating film IF1 containing an inorganic material and the insulating film IF2 containing an organic material. Therefore, in the separator SP1 (SP2) in the second embodiment, since the inorganic material and the organic material are separated, there is a problem of uneven distribution of the organic material that occurs when the inorganic material and the organic material are mixed. Absent. From this, according to this Embodiment 2, the fall of the shutdown function resulting from the uneven distribution of an organic material can be suppressed. That is, according to the second embodiment, it is possible to suppress the blockage failure of the pores (micropores) due to the uneven distribution of the organic material in the separator SP1 (SP2) at the time of abnormal heat generation of the lithium ion battery. it can. As a result, according to the second embodiment, the shutdown function can be surely exhibited without causing the failure of the electrode reaction to be blocked, thereby effectively blocking the electrode reaction of the lithium ion battery. it can.

  In the second embodiment, since the separator SP1 and the separator SP2 are bonded and integrated on both surfaces of the positive electrode, the positive electrode and the separator SP1 or between the positive electrode and the separator SP2 are configured. The gap which arises can be eliminated. As a result, it is possible to prevent an internal short circuit in the lithium ion battery due to the metal foreign matter, thereby improving the reliability of the lithium ion battery.

<Method for Manufacturing Lithium Ion Battery in Embodiment 2>
The lithium ion battery according to the second embodiment is configured as described above, and the manufacturing method thereof will be described below with reference to the drawings. In the second embodiment, an example in which the positive electrode, the ceramic powder CRS, and the organic material OM are integrally formed in a layered manner will be described.

First, as shown in FIGS. 10 and 11, slurry SL1 containing positive electrode active material PAS is produced by the same method as in the first embodiment described above. Furthermore, in the second embodiment, for example, as shown in FIG. 37, ceramic powder CRS (particle size is 4 μm, for example) such as alumina (Al ₂ O ₃ ) or silica (SiO ₂ ) is prepared. Then, as shown in FIG. 38, for example, a solution in which a binder (binder) made of polyvinylidene fluoride is dissolved in N-methylpyrrolidone (NMP) is formed, and ceramic powder CRS is kneaded with this solution to form a slurry. SL4 is produced. Similarly, in the second embodiment, for example, as shown in FIG. 39, for example, high density polyethylene (melting point: 130 to 137 ° C.), linear low density polyethylene (melting point: 122 to 124 ° C.), etc. An organic material OM (particle diameter is, for example, 1 μm) made of polyolefin resin is prepared. Then, as shown in FIG. 40, for example, a solution in which a binder (binder) made of polyvinylidene fluoride is dissolved in N-methylpyrrolidone (NMP) is formed, and an organic material OM is kneaded with this solution to obtain a slurry SL5. Is made.

Then, as shown in FIG. 41, slurry SL1 containing positive electrode active material PAS and a binder (binder) is apply | coated to positive electrode plate (positive electrode collector) PEP. Specifically, as shown in FIG. 41, for example, using a die coater DC, a positive electrode active material PAS (including a conductive additive) is applied onto a positive electrode plate PEP made of aluminum. Subsequently, slurry SL4 in which ceramic powder CRS is kneaded is applied onto slurry SL1 applied to positive electrode plate PEP using die coater DC. Next, the slurry SL5 in which the organic material OM is kneaded is applied onto the slurry SL4 using the die coater DC. Here, first, using the die coater DC, the slurry SL1 in which the positive electrode active material PAS is kneaded is applied on the positive electrode plate PEP, and then the slurry SL4 in which the ceramic powder CRS is kneaded is applied on the slurry SL1. Further, the sequential coating method for applying the slurry SL5 in which the organic material OM is kneaded has been described. For example, the slurry SL1 in which the positive electrode active material PAS is kneaded on the positive electrode plate PEP and the ceramic powder CRS are kneaded. A simultaneous coating method in which slurry SL4 and slurry SL5 in which organic particles are kneaded are simultaneously coated on positive electrode plate PEP using die coater DC can also be used.

  Next, as shown in FIG. 42, slurry SL1, slurry SL4, and slurry SL5 applied to positive electrode plate PEP are dried. Specifically, for example, by heating the positive electrode plate PEP at 120 ° C. or lower, the slurry SL1, the slurry SL4, and the slurry SL5 applied on the positive electrode plate PEP are dried. The heat treatment here needs to be set to a temperature at which the organic particles constituting the organic material OM do not melt. Thereby, the positive electrode active material PAS can be formed on the positive electrode plate PEP, and the insulating film IF1 containing the ceramic powder CRS can be formed on the positive electrode active material PAS. Then, the insulating film IF2 containing the organic material OM can be formed on the insulating film IF1.

  Then, after forming the positive electrode active material PAS and the insulating film IF1 containing the ceramic powder CRS and the insulating film IF2 containing the organic material OM on one surface (first surface) of the positive electrode plate PEP, as shown in FIG. The other surface (second surface) of the positive electrode plate PEP is coated with the slurry SL1 kneaded with the positive electrode active material PAS, the slurry SL4 kneaded with the ceramic powder CRS, and the slurry SL5 kneaded with the organic material OM. . Thereafter, for example, by heating the positive electrode plate PEP at 120 ° C. or lower, the slurry SL1, the slurry SL4, and the slurry SL5 applied to the other surface of the positive electrode plate PEP are dried. As a result, as shown in FIG. 44, the positive electrode active material PAS is formed on the positive electrode plate PEP also on the other surface of the positive electrode plate PEP, and the insulating film containing the ceramic powder CRS is formed on the positive electrode active material PAS. IF1 can be formed. Then, the insulating film IF2 containing the organic material OM can be formed on the insulating film IF1.

  After the positive electrode active material PAS, the insulating film IF1 and the insulating film IF2 are thus formed on both surfaces of the positive electrode plate PEP, as shown in FIG. 45, the positive electrode plate PEP is heated and heated using a roller RL. Perform pressure treatment. This heating / pressurizing process is performed at 120 ° C. or less, for example. Thereby, it is possible to increase the density of the positive electrode active material PAS applied to the positive electrode plate PEP. As described above, as shown in FIG. 36, the positive electrode active material PAS is formed on both surfaces of the positive electrode plate PEP, and an inorganic material such as ceramic (alumina or silica) is used so as to be in direct contact with the positive electrode active material PAS. An insulating film IF1 containing a material can be formed. Then, the insulating film IF2 containing an organic material such as polyolefin resin can be formed so as to be in direct contact with the insulating film IF1. That is, in the second embodiment, the separator SP1 (SP2) can be formed from the laminated film of the insulating film IF1 and the insulating film IF2.

  According to the second embodiment, the separator SP1 (SP2) made of the insulating film IF1 made of the ceramic powder CRS and the insulating film IF2 made of the organic material OM and the positive electrode are collectively dried and pressed to form a layer. Since they are integrally formed, the number of processes can be reduced and the manufacturing cost can be reduced. In addition, when the battery abnormally generates heat, the electrode reaction is blocked by reliably causing a shutdown function without causing a failure in blocking the electrode reaction due to poor blockage due to the uneven distribution of organic particles in the separator SP1 (SP2). be able to.

  Since the subsequent steps are substantially the same as those in the first embodiment, the description thereof will be omitted. As described above, the lithium ion battery according to the second embodiment can be manufactured.

(Embodiment 3)
<Characteristics in Embodiment 3>
The configuration of the lithium ion battery in the third embodiment is substantially the same as the configuration of the lithium ion battery in the second embodiment. That is, in the second embodiment, an example in which the positive electrode and the separator are integrated and the separator is formed from a laminated film of a first insulating film containing an inorganic material and a second insulating film containing an organic material will be described. did. In Embodiment 3, the positive electrode and the separator are integrated, and the separator is made up of a first insulating film (organic insulating film) containing an organic material and a second insulating film (inorganic insulating film) containing an inorganic material. An example of forming from a laminated film will be described.

  FIG. 46 is a cross-sectional view showing an integrated structure of the separator and the positive electrode in the third embodiment. As shown in FIG. 46, in the integrated structure of the separator and the positive electrode in the present third embodiment, the positive electrode active material PAS is formed on both surfaces of the positive electrode plate PEP, so that the positive electrode active material PAS is in direct contact with the positive electrode active material PAS. For example, an insulating film IF1 containing an organic material OM such as polyolefin resin is formed. An insulating film IF2 containing an inorganic material such as ceramic powder CRS (alumina or silica) is formed so as to be in direct contact with the insulating film IF1. That is, in the third embodiment, the separator SP1 (SP2) is formed from the laminated film of the insulating film IF1 and the insulating film IF2.

  Thus, in this Embodiment 3, separator SP1 (SP2) is formed from the laminated film of insulating film IF1 containing an organic material, and insulating film IF2 containing an inorganic material. Therefore, even in the separator SP1 (SP2) in the third embodiment, since the inorganic material and the organic material are separated, there is a problem of uneven distribution of the organic material that occurs when the inorganic material and the organic material are mixed. Absent. From this, according to this Embodiment 3, like the said Embodiment 2, the fall of the shutdown function resulting from the uneven distribution of an organic material can be suppressed. That is, according to the third embodiment, it is possible to suppress the blockage failure of the pores (micropores) due to the uneven distribution of the organic material in the separator SP1 (SP2) at the time of abnormal heat generation of the lithium ion battery. it can. As a result, according to the third embodiment, the shutdown function can be surely exhibited without causing failure of the electrode reaction to be blocked, thereby effectively blocking the electrode reaction of the lithium ion battery. it can.

  In Embodiment 3, the separator SP1 and the separator SP2 are bonded and integrated on both surfaces of the positive electrode, so that the positive electrode and the separator SP1 or between the positive electrode and the separator SP2 are integrated. The gap which arises can be eliminated. As a result, it is possible to prevent an internal short circuit in the lithium ion battery due to the metal foreign matter, thereby improving the reliability of the lithium ion battery.

<Method for Manufacturing Lithium Ion Battery in Embodiment 3>
The lithium ion battery according to Embodiment 3 is configured as described above, and the manufacturing method thereof will be described below with reference to the drawings. Also in the third embodiment, an example in which the positive electrode, the ceramic powder CRS, and the organic material OM are integrally formed in a layered manner will be described.

  As shown in FIG. 47, for example, a die coater DC is used to apply a slurry SL1 containing a positive electrode active material PAS (including a conductive additive) on a positive electrode plate PEP made of aluminum. Subsequently, using the die coater DC, the slurry SL5 in which the organic material OM is kneaded is applied onto the slurry SL1 applied to the positive electrode plate PEP. Thereafter, slurry SL4 in which ceramic powder CRS is kneaded is applied onto slurry SL5 containing organic material OM using die coater DC. Here, first, using the die coater DC, the slurry SL1 in which the positive electrode active material PAS is kneaded is applied on the positive electrode plate PEP, and then the slurry SL5 in which the organic material OM is kneaded is applied on the positive electrode active material PAS. Further, the sequential application method for applying the slurry SL4 in which the ceramic powder CRS is kneaded has been described. For example, the slurry SL1 in which the positive electrode active material PAS is kneaded on the positive electrode plate PEP and the organic material OM are kneaded. It is also possible to use a simultaneous coating method in which the slurry SL5 and the slurry SL4 in which the ceramic powder CRS is kneaded are simultaneously coated on the positive electrode plate PEP using the die coater DC.

  Next, as shown in FIG. 48, slurry SL1, slurry SL5, and slurry SL4 applied to positive electrode plate PEP are dried. Specifically, for example, by heating the positive electrode plate PEP at 120 ° C. or lower, the slurry SL1, the slurry SL5, and the slurry SL4 applied on the positive electrode plate PEP are dried. The heat treatment here needs to be set to a temperature at which the organic particles constituting the organic material OM do not melt. Thereby, the positive electrode active material PAS can be formed on the positive electrode plate PEP, and the insulating film IF1 containing the organic material OM can be formed on the positive electrode active material PAS. Then, the insulating film IF2 containing the ceramic powder CRS can be formed on the insulating film IF1.

  Then, after forming the positive electrode active material PAS and the insulating film IF2 containing the ceramic powder CRS and the insulating film IF1 containing the organic material OM on one surface (first surface) of the positive electrode plate PEP, as shown in FIG. The other surface (second surface) of the positive electrode plate PEP is coated with the slurry SL1 kneaded with the positive electrode active material PAS, the slurry SL5 kneaded with the organic material OM, and the slurry SL4 kneaded with the ceramic powder CRS. . Thereafter, for example, by heating the positive electrode plate PEP at 120 ° C. or lower, the slurry SL1, the slurry SL5, and the slurry SL4 applied to the other surface of the positive electrode plate PEP are dried. As a result, as shown in FIG. 50, the positive electrode active material PAS is formed on the other surface of the positive electrode plate PEP on the positive electrode plate PEP, and the insulating film IF1 containing the organic material OM is formed on the positive electrode active material PAS. Can be formed. Then, the insulating film IF2 containing the ceramic powder CRS can be formed on the insulating film IF1.

  In this way, after the positive electrode active material PAS and the insulating film IF1 and the insulating film IF2 are formed on both surfaces of the positive electrode plate PEP, the positive electrode plate PEP is heated and heated using a roller RL as shown in FIG. Perform pressure treatment. This heating / pressurizing process is performed at 120 ° C. or less, for example. Thereby, it is possible to increase the density of the positive electrode active material PAS applied to the positive electrode plate PEP. As described above, as shown in FIG. 46, the positive electrode active material PAS is formed on both surfaces of the positive electrode plate PEP, and an organic material such as a polyolefin-based resin is included so as to be in direct contact with the positive electrode active material PAS. The insulating film IF1 can be formed. Then, the insulating film IF2 containing an inorganic material such as ceramic (alumina or silica) can be formed so as to be in direct contact with the insulating film IF1. That is, in the third embodiment, the separator SP1 (SP2) can be formed from the laminated film of the insulating film IF1 and the insulating film IF2.

  According to the third embodiment, the separator SP1 (SP2) made of the insulating film IF1 made of the organic material OM and the insulating film IF2 made of the ceramic powder CRS and the positive electrode are collectively dried and pressed to form a layer. Since they are integrally formed, the number of processes can be reduced and the manufacturing cost can be reduced. In addition, when the battery abnormally generates heat, the electrode reaction is blocked by reliably causing a shutdown function without causing a failure in blocking the electrode reaction due to poor blockage due to the uneven distribution of organic particles in the separator SP1 (SP2). be able to.

  Since the subsequent steps are substantially the same as those in the first embodiment, the description thereof will be omitted. As described above, the lithium ion battery according to the third embodiment can be manufactured.

  As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the invention is not limited to the embodiment, and various modifications can be made without departing from the scope of the invention. Needless to say.

  In Embodiments 1 to 3, the example in which the separators are integrally formed on both surfaces of the positive electrode has been described. However, the technical idea of the present invention is not limited to this. For example, a separator can be integrally formed on one side of the positive electrode, and another separator can be integrally formed on one side of the negative electrode. Furthermore, a separator can be integrally formed on both sides of the negative electrode. Also, the technical idea of the present invention can be applied.

  Here, as described in the first embodiment, the internal short circuit of the lithium ion battery due to the mechanism of dissolution / precipitation of the metal foreign matter is caused by the adhesion of the metal foreign matter to the positive electrode. Therefore, in order to effectively suppress the internal short circuit of the lithium ion battery due to the mechanism of dissolution / deposition of the metal foreign matter, it is important to prevent the metal foreign matter from adhering to the positive electrode. Therefore, in the technical idea of the present invention, the electrode formed integrally with the separator may be either a positive electrode or a negative electrode, but in particular, an internal short circuit of a lithium ion battery by a mechanism of dissolution / precipitation of metal foreign matter. From the viewpoint of effectively suppressing the above, it is desirable that the separators are integrally formed on both surfaces of the positive electrode as described in the first to third embodiments.

  In the first to third embodiments, the technical idea of the present invention has been described by taking a lithium ion battery as an example. However, the technical idea of the present invention is not limited to a lithium ion battery. It can be widely applied to an electricity storage device (for example, a battery or a capacitor) including a positive electrode, a negative electrode, and a separator that electrically separates the positive electrode and the negative electrode.

  The present invention can be widely used in, for example, a manufacturing industry for manufacturing a battery represented by a lithium ion battery.

CAP Battery cover CR Shaft core CRS Ceramic powder CS Exterior can CU Charger DC Die coater DC1 Die coater DC2 Die coater EL Electrolytic solution IF1 Insulating film IF2 Insulating film LIB Lithium ion battery NAS Negative electrode active material NEL Negative electrode NEP Negative electrode plate NT Negative electrode lead plate NTAB Negative electrode current collector tab OM Organic material PAS Positive electrode active material PEL Positive electrode PEP Positive electrode plate PMP1 Supply pump PMP2 Supply pump PR Positive electrode current collector ring PT Positive electrode lead plate PTAB Positive electrode current collector tab RL Roller RL1 Roller SL1 Slurry SL2 Slurry SL3 Slurry SL4 slurry SL5 slurry SP separator SP1 separator SP2 separator WRF electrode winding body

Claims (24)

(A) applying a first slurry containing an active material on the electrode plate, and applying a second slurry containing organic particles and inorganic particles on the first slurry;
(B) After the step (a), the applied first slurry and second slurry are dried to form the active material on the electrode plate, and the organic particles and the inorganic particles are formed on the active material. Forming a separator comprising:
(C) After the said (b) process, The process of performing the pressurization process under a heating with respect to the said active material and the said separator is provided, The manufacturing method of a lithium ion battery characterized by the above-mentioned. It is a manufacturing method of the lithium ion battery according to claim 1,
In the step (a), the average particle size of the organic particles is smaller than the average particle size of the inorganic particles. It is a manufacturing method of the lithium ion battery according to claim 1,
The method for producing a lithium ion battery, wherein the organic particles are made of a polyolefin resin. It is a manufacturing method of the lithium ion battery according to claim 1,
The said inorganic particle is comprised from the ceramic, The manufacturing method of the lithium ion battery characterized by the above-mentioned. It is a manufacturing method of the lithium ion battery according to claim 4,
The said inorganic particle is comprised from the alumina or the silica, The manufacturing method of the lithium ion battery characterized by the above-mentioned. (A) applying a first slurry containing an active material on the first surface of the electrode plate, and applying a second slurry containing organic particles and inorganic particles on the first slurry;
(B) After the step (a), the active material is formed on the first surface of the electrode plate by drying the first slurry and the second slurry applied on the first surface, Forming a first separator containing the organic particles and the inorganic particles on the active material;
(C) After the step (b), a step of applying the first slurry on the second surface of the electrode plate opposite to the first surface, and applying the second slurry on the first slurry. When,
(D) After the step (c), the active material is formed on the second surface of the electrode plate by drying the first slurry and the second slurry applied on the second surface, Forming a second separator containing the organic particles and the inorganic particles on the active material;
(E) After the step (d), the active material and the first separator formed on the first surface, and the active material and the second separator formed on the second surface, And a step of applying pressure treatment under heating. A method for producing a lithium ion battery, comprising: (A) applying a first slurry containing an active material on the electrode plate, applying a second slurry containing a first material on the first slurry, and applying a second slurry different from the first material on the second slurry; Applying a third slurry containing two substances;
(B) After the step (a), by drying the applied first slurry, second slurry, and third slurry, the active material is formed on the electrode plate, and the first slurry is formed on the active material. Forming a separator comprising a first insulating film containing one substance and a second insulating film containing the second substance;
(C) After the said (b) process, The process of performing the pressurization process under a heating with respect to the said active material and the said separator is provided, The manufacturing method of a lithium ion battery characterized by the above-mentioned. It is a manufacturing method of the lithium ion battery according to claim 7,
The first substance is inorganic particles;
The second substance is organic particles;
The first insulating film is an inorganic insulating film containing the inorganic particles,
The method of manufacturing a lithium ion battery, wherein the second insulating film is an organic insulating film containing the organic particles. It is a manufacturing method of the lithium ion battery according to claim 8,
The first material is ceramic;
The method of manufacturing a lithium ion battery, wherein the second substance is a polyolefin resin. It is a manufacturing method of the lithium ion battery according to claim 9,
The method of manufacturing a lithium ion battery, wherein the first substance is alumina or silica. It is a manufacturing method of the lithium ion battery according to claim 7,
The first substance is an organic particle,
The second substance is inorganic particles,
The first insulating film is an organic insulating film containing the organic particles,
The method of manufacturing a lithium ion battery, wherein the second insulating film is an inorganic insulating film containing the inorganic particles. It is a manufacturing method of the lithium ion battery according to claim 11,
The first substance is a polyolefin resin,
The method of manufacturing a lithium ion battery, wherein the second substance is ceramic. It is a manufacturing method of the lithium ion battery according to claim 12,
The method for manufacturing a lithium ion battery, wherein the second substance is alumina or silica. (A) Applying a first slurry containing an active material on a first surface of an electrode plate, applying a second slurry containing a first material on the first slurry, and applying the first material on the second slurry. Applying a third slurry containing a second substance different from
(B) After the step (a), by drying the first slurry, the second slurry, and the third slurry applied on the first surface, the active surface is formed on the first surface of the electrode plate. Forming a material and forming a first separator comprising a first insulating film containing the first material and a second insulating film containing the second material on the active material;
(C) After the step (b), the first slurry is applied on the second surface of the electrode plate opposite to the first surface, and the second slurry is applied on the first slurry, Applying the third slurry onto the second slurry;
(D) After the step (c), by drying the first slurry, the second slurry, and the third slurry applied on the second surface, the active surface is formed on the second surface of the electrode plate. Forming a material and forming a second separator comprising the first insulating film containing the first material and the second insulating film containing the second material on the active material;
(E) After the step (d), the active material and the first separator formed on the first surface, and the active material and the second separator formed on the second surface, And a step of applying pressure treatment under heating. A method for producing a lithium ion battery, comprising: (A) a positive electrode;
(B) a negative electrode;
(C) a separator integrated with any one of the positive electrode and the negative electrode;
The separator includes organic particles and inorganic particles,
The lithium ion battery, wherein an average particle size of the organic particles is smaller than an average particle size of the inorganic particles. The lithium ion battery according to claim 15,
The organic particles are composed of a polyolefin resin,
The said inorganic particle is comprised from the ceramic, The lithium ion battery characterized by the above-mentioned. The lithium ion battery according to claim 16,
The said inorganic particle is comprised from the alumina or the ceramic, The lithium ion battery characterized by the above-mentioned. (A) a positive electrode;
(B) a negative electrode;
(C) a separator integrated with any one of the positive electrode and the negative electrode;
The separator is
(C1) a first insulating film formed on the electrode;
(C2) A lithium ion battery, comprising: a second insulating film formed on the first insulating film. The lithium ion battery according to claim 18,
The first insulating film is an inorganic insulating film containing inorganic particles,
The lithium ion battery, wherein the second insulating film is an organic insulating film containing organic particles. The lithium ion battery according to claim 19,
The first insulating film is the inorganic insulating film containing ceramic,
The lithium ion battery, wherein the second insulating film is the organic insulating film containing a polyolefin-based resin. The lithium ion battery according to claim 20,
The lithium ion battery, wherein the first insulating film is the inorganic insulating film containing alumina or silica. The lithium ion battery according to claim 18,
The first insulating film is an organic insulating film containing organic particles,
The lithium ion battery, wherein the second insulating film is an inorganic insulating film containing inorganic particles. The lithium ion battery according to claim 22,
The first insulating film is the organic insulating film containing a polyolefin resin,
The lithium ion battery, wherein the second insulating film is the inorganic insulating film containing ceramic. The lithium ion battery according to claim 23,
The lithium ion battery, wherein the second insulating film is the inorganic insulating film containing alumina or silica.

Images