Battery and method for manufacturing the same

Abstract

The present invention provides a battery and a method for manufacturing the same that suppresses the expansion of a battery cell. The battery (1) has an electrode body, which includes a positive electrode plate (210), a negative electrode plate (220), and a separator (230) disposed between the positive electrode plate (210) and the negative electrode plate (220). A first adhesive layer (241) is provided between the positive electrode plate (210) and the separator (230), and a second adhesive layer (242) is provided between the negative electrode plate (220) and the separator (230). The unit area weight of the first adhesive layer (241) is smaller than the unit area weight of the second adhesive layer (242), and the total unit area weight of the first adhesive layer (241) and the unit area weight of the second adhesive layer (242) is 0.03 g / m 2 Above and 0.15g / m 2 the following.

Description

Technical Field

[0001] The invention relates to a battery and a method for manufacturing the same. Background Art

[0002] Conventionally, there is known a battery including an electrode body including a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate, wherein an adhesive layer is provided between the electrode plates (positive electrode plate and negative electrode plate) and the separator.

[0003] If the adhesion between the electrode plate (especially the positive plate) and the separator in the electrode body is too strong, the gap between the electrode plates may not be sufficiently vacated during the drying process of the battery cell, and the path for discharging water from the battery cell cannot be properly ensured. In this case, the residual water reacts with the electrode active material to generate gas, and the battery cell is prone to expansion. Therefore, it is necessary to ensure a moderate path for discharging water during the drying process. From the above point of view, previous batteries may not have a sufficient structure. Summary of the invention

[0004] An object of the present invention is to provide a battery and a method for manufacturing the battery that suppresses expansion of a battery cell.

[0005] The battery of the present invention has an electrode body, which includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate. A first adhesive layer is provided between the positive electrode plate and the separator, and a second adhesive layer is provided between the negative electrode plate and the separator. The unit area weight (Japanese: basis weight) of the first adhesive layer is smaller than the unit area weight of the second adhesive layer, and the total unit area weight of the first adhesive layer and the unit area weight of the second adhesive layer is 0.03 g / m 2 Above and 0.15g / m 2 the following.

[0006] The manufacturing method of the battery of the present invention comprises a step of forming an electrode body, wherein the electrode body comprises a positive electrode plate, a negative electrode plate, and a separator arranged between the positive electrode plate and the negative electrode plate and having a first surface facing the positive electrode plate and a second surface facing the negative electrode plate. The step of forming the electrode body comprises: forming a first adhesive layer on the first surface of the separator, forming a second adhesive layer on the second surface of the separator; bonding the separator to the positive electrode plate via the first adhesive layer; and bonding the separator to the negative electrode plate via the second adhesive layer. The unit area weight of the first adhesive layer is smaller than the unit area weight of the second adhesive layer, and the total unit area weight of the first adhesive layer and the unit area weight of the second adhesive layer is 0.03 g / m 2 Above and 0.15g / m 2 the following.

[0007] In addition, in this specification, the "weight per unit area" of the adhesive layer refers to the mass of the adhesive particles contained in the adhesive layer per unit area of ​​the adhesive surface. The theoretical value of the "weight per unit area" is obtained by (the area of ​​the adhesive layer per unit area) × (the thickness of the adhesive layer) × (the density of the adhesive layer), but it can also be uniquely obtained by measuring the number of adhesive particles contained per unit area.

[0008] The above and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a three-dimensional diagram of a square secondary battery.

[0010] Figure 2 This is a cross-sectional view showing the structure of an electrode body according to one embodiment.

[0011] Figure 3 Yes means Figure 2 A cross-sectional view of the separator and bonding layer in the electrode body is shown.

[0012] Figure 4 It is a cross-sectional view showing the structure of an electrode body according to a modified example.

[0013] Figure 5 Yes means Figure 4 A cross-sectional view of the separator and bonding layer in the electrode body is shown.

[0014] Figure 6 It is a plan view showing an example of the arrangement of the adhesive layer on the separator.

[0015] Figure 7 It is a plan view showing another example of the arrangement of the adhesive layer on the separator.

[0016] Figure 8 It is a plan view showing still another example of the arrangement of the adhesive layer on the separator.

[0017] Fig. 9 It is a plan view showing still another example of the arrangement of the adhesive layer on the separator.

[0018] Fig.10 This is a graph showing the relationship between the ratio of the weight per unit area of ​​the adhesive layers formed on both sides of the separator and the battery cell expansion rate (relative to the battery cell thickness in a standard state). DETAILED DESCRIPTION

[0019] Hereinafter, an embodiment of the present invention will be described. In addition, the same reference numerals may be given to the same or corresponding parts, and the description thereof may not be repeated.

[0020] In addition, in the embodiments described below, when the number, quantity, etc. are mentioned, unless otherwise specified, the scope of the present invention is not necessarily limited to the number, quantity, etc. In addition, in the following embodiments, each component is not necessarily essential to the present invention unless otherwise specified.

[0021] In addition, in this specification, the descriptions of "comprise", "include", and "have" are open-ended. That is, when a certain structure is included, other structures other than the structure may be included, or other structures other than the structure may not be included. In addition, the present invention is not necessarily limited to achieving all the effects mentioned in this embodiment.

[0022] In this specification, "battery" is not limited to lithium-ion batteries, and may include other batteries such as nickel-metal hydride batteries. In this specification, "electrode" may be a general term for positive electrodes and negative electrodes. In addition, "electrode plate" may be a general term for positive plates and negative plates.

[0023] Figure 1 1 is a three-dimensional diagram of a square secondary battery 1. Figure 1 As shown, the square secondary battery 1 includes a battery case 100 , an electrode body 200 , a positive electrode terminal 300 , a negative electrode terminal 400 , and an insulating member 500 .

[0024] The battery case 100 is composed of a rectangular outer casing 110 having an opening and a bottomed rectangular tube, and a sealing plate 120 for sealing the opening of the rectangular outer casing 110. The rectangular outer casing 110 and the sealing plate 120 are preferably made of metal, preferably aluminum or an aluminum alloy.

[0025] The electrode body 200 is accommodated together with the electrolyte in the battery case 100. The positive electrode terminal 300 and the negative electrode terminal 400 are fixed to the sealing plate 120 via the insulating member 500 made of resin.

[0026] The battery of the present invention is not limited to a square shape. The shapes of the battery case 100 and the electrode body 200 are not particularly limited. For example, the electrode body 200 can be a laminated type, a flat type, or a cylindrical type. Preferably, the electrode body 200 is a laminated type.

[0027] When manufacturing the square secondary battery 1, after the electrode body 200 is housed in the square outer body 110, the square outer body 110 is sealed by the sealing plate 120. In this state, a drying process is performed to dry the inside of the battery case 100. Through the drying process, the moisture contained in the adhesive material used when making the electrode body 200 is released. After that, the electrolyte is injected into the battery case 100 through the injection hole provided in the sealing plate 120.

[0028] Figure 2 2 is a cross-sectional view showing the structure of an electrode body 200 including a positive electrode plate 210 , a negative electrode plate 220 , a separator 230 , and an adhesive layer 240 . Figure 3 It is a cross-sectional view showing the separator 230 and the adhesive layer 240 in the electrode body 200 .

[0029] The electrode body 200 has a structure in which a plurality of positive electrode plates 210, a plurality of negative electrode plates 220, and a plurality of separators 230 are stacked in this order. Generally, the negative electrode plates 220 are arranged as electrode plates at both ends of the electrode body 200 in the stacking direction.

[0030] The electrode body 200 may also have a structure in which a separator 230 is folded in a zigzag manner and interposed between the positive electrode plate 210 and the negative electrode plate 220. Figure 2 In the example, a single-sheet diaphragm 230 is used.

[0031] The positive electrode plate 210 includes a positive electrode core and a positive electrode mixture layer formed on the positive electrode core. As the positive electrode core, for example, a foil of a metal such as aluminum that is stable within the potential range of the positive electrode plate 210, a film in which the metal is arranged on the surface, etc. can be used. The positive electrode mixture layer may contain a positive electrode active material, a conductive material, and a binder. The positive electrode mixture layer is generally formed on both sides of the positive electrode core. The positive electrode plate 210 can be manufactured by forming the positive electrode mixture layer on both sides of the positive electrode core. By applying a positive electrode mixture slurry containing a positive electrode active material, a conductive material, a binder, etc., and drying the coating, rolling is performed, so that the positive electrode mixture layer can be formed on both sides of the positive electrode core.

[0032] As an example of a positive electrode active material forming a positive electrode mixture layer, a lithium-containing transition metal oxide can be cited. The metal element constituting the lithium-containing transition metal oxide is, for example, at least one selected from magnesium (Mg), aluminum (Al), calcium (Ca), scandium (Sc), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge), yttrium (Y), zirconium (Zr), tin (Sn), antimony (Sb), tungsten (W), lead (Pb) and bismuth (Bi). Among them, it is preferred that the positive electrode active material contains at least one selected from cobalt, nickel and manganese.

[0033] As examples of conductive materials forming the positive electrode mixture layer, carbon materials such as carbon black (CB), acetylene black (AB), Ketjen black, and graphite can be listed. In addition, as a binder, materials such as organic resins, acrylic resins, epoxy resins, styrene-butadiene rubbers, silicone rubbers, and polyvinylidene fluoride (PVdF) can be used. These materials can be used alone or in combination of two or more.

[0034] The negative electrode plate 220 includes a negative electrode core and a negative electrode mixture layer formed on the negative electrode core. As the negative electrode core, for example, a foil of a metal such as copper that is stable within the potential range of the negative electrode plate 220, a film in which the metal is arranged on the surface, etc. can be used. The negative electrode mixture layer may contain a binder in addition to the negative electrode active material. The negative electrode mixture layer is generally formed on both sides of the negative electrode core. The negative electrode plate 220 can be manufactured by forming the negative electrode mixture layer on both sides of the negative electrode core. By applying a negative electrode mixture slurry containing a negative electrode active material, a conductive material, and a binder, and drying the coating, rolling is performed, so that the negative electrode mixture layer can be formed on both sides of the negative electrode core.

[0035] The negative electrode active material forming the negative electrode mixture layer is not particularly limited as long as it can reversibly absorb and release lithium ions. For example, carbon materials such as natural graphite and artificial graphite, metals such as silicon (Si) and tin (Sn) alloyed with lithium, or alloys containing metal elements such as silicon and tin, composite oxides, etc. can be used. The negative electrode active material can be used alone or in combination of two or more. The negative electrode active material preferably contains a carbon material, a silicon material or lithium metal. The negative electrode active material is further preferably a carbon material as the main body.

[0036] As the binder contained in the negative electrode mixture layer, the same material as that contained in the positive electrode mixture layer can be used. In the case of using an aqueous solvent to modulate the negative electrode mixture slurry, styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC) or its salt, polyacrylic acid (PAA) or its salt, polyvinyl alcohol (PVA) etc. can also be used.

[0037] As the positive electrode plate 210, a relatively large positive electrode plate having a long side of 100 mm or more (as an example, about 140 mm) and a short side of 50 mm or more (as an example, about 70 mm in height) can be used. For example, 50 or more positive electrode plates 210 and negative electrode plates 220 can be stacked, each of which is about 60 sheets (as an example).

[0038] The separator 230 is composed of a porous substrate 231 and a porous heat-resistant layer 232 formed on one surface of the substrate 231. By providing the heat-resistant layer 232, it is less likely to cause the separator 230 to break due to, for example, mixing with foreign matter, piercing by a nail, etc., or it is possible to suppress the shrinkage of the separator 230 when the temperature rises. In order to suppress the increase in the thickness of the electrode body 200 and improve cost-effectiveness, it is preferred to form the heat-resistant layer 232 only on one surface of the substrate 231.

[0039] The porous substrate 231 can also function as a diaphragm alone. The substrate 231 is composed of a resin layer or a non-woven fabric. As the substrate 231, a porous film having ion permeability and electrical insulation can be used. The thickness of the substrate 231 is, for example, about 1 μm or more and about 20 μm or less. As the material of the substrate 231, olefin resins such as polyethylene, polypropylene, ethylene-propylene copolymers, ethylene, propylene, and copolymers with other α-olefins can be exemplified. The substrate 231 is preferably composed of a polyolefin layer. The melting point of the substrate 231 is generally about 200°C or less.

[0040] The porous film constituting the substrate 231 has a large number of pores for lithium ions to pass through, but the surface roughness is smaller than that of the heat-resistant layer 232, and the surface is flatter than that of the heat-resistant layer 232. The size (maximum length) of the pores or recesses existing on the surface of the substrate 231 is, for example, less than 0.5 μm, preferably less than 0.3 μm.

[0041] The heat-resistant layer 232 may be composed of a resin having a higher melting point or softening point than the resin constituting the substrate 231, such as an aromatic polyamide resin, polyimide, polyamide-imide, etc. The heat-resistant layer 232 is preferably composed of an inorganic compound as a main component. The heat-resistant layer 232 is preferably composed of insulating inorganic particles and a binder for bonding the inorganic particles to each other and the inorganic particles to the substrate 231. The heat-resistant layer 232 has ion permeability and electrical insulation properties similar to the substrate 231. The thickness of the heat-resistant layer 232 is, for example, about 1 μm or more and about 10 μm or less, preferably about 1 μm or more and about 6 μm or less.

[0042] As the inorganic particles that are the main component of the heat-resistant layer 232, for example, at least one selected from alumina, boehmite, aluminum hydroxide, silicon dioxide, titanium dioxide, and zirconium oxide can be used. Alumina is preferably used as the inorganic particles. The content of the inorganic particles is preferably 85% by mass or more and 99.9% by mass or less, and more preferably 90% by mass or more and 99.5% by mass or less relative to the mass of the heat-resistant layer 232.

[0043] The shape of the inorganic particles is not particularly limited, for example, spherical particles, quadrangular particles, etc. can be used. The average particle size of the spherical particles or the average length of one side of the quadrangular particles is preferably about 0.1 μm or more and about 1.5 μm or less, and more preferably about 0.5 μm or more and about 1.2 μm or less. If the particle size of the inorganic particles is within this range, a heat-resistant layer 232 with good ion permeability and excellent durability can be formed. The average particle size of the inorganic particles and the average length of the side are measured by observing the surface of the heat-resistant layer 232 using a scanning electron microscope (SEM). Specifically, 100 inorganic particles can be randomly selected from the SEM image of the heat-resistant layer 232, and the diameter of the circumscribed circle of each particle or the length of the side can be measured and averaged and calculated.

[0044] As the binder constituting the heat-resistant layer 232, the same binder as that contained in the positive electrode mixture layer and the negative electrode mixture layer can be used. The content of the binder is preferably 0.1% by mass or more and 15% by mass or less, and more preferably 0.5% by mass or more and 10% by mass or less relative to the mass of the heat-resistant layer 232. The heat-resistant layer 232 is formed, for example, by applying a slurry containing inorganic particles and a binder to one side of the porous film constituting the substrate 231 and drying the coating.

[0045] The heat-resistant layer 232 formed in this way has higher permeability to water and ions than the base material 231 .

[0046] The separator 230 is bonded to the positive electrode mixture layer of the positive electrode plate 210 and the negative electrode mixture layer of the negative electrode plate 220 through the bonding layer 240 containing bonding particles. Figure 2 As shown, the heat-resistant layer 232 of the separator 230 and the positive electrode mixture layer of the positive electrode plate 210 are bonded by an adhesive layer 241 (first adhesive layer), and the base material 231 of the separator 230 and the negative electrode mixture layer of the negative electrode plate 220 are bonded by an adhesive layer 242 (second adhesive layer).

[0047] The thickness of the adhesive layer 240 is, for example, about 0.1 μm or more and 1 μm or about 0.2 μm or more and 0.9 μm or less. The thickness of the adhesive layer 240 is determined by the amount of adhesive particles and their particle size, etc. The adhesive layer 240 is formed, for example, by applying a slurry containing adhesive particles to the surface of the diaphragm 230 and drying it. As a slurry of adhesive particles, a so-called emulsion in which tiny adhesive particles are dispersed in water can be used. In this case, a diaphragm 230 with an adhesive layer 240 having adhesive layers 240 composed of adhesive particles formed on both sides can be obtained.

[0048] The electrode body 200 can be obtained by laminating and hot pressing the negative electrode plate 220, the separator 230 with the adhesive layer 240, the positive electrode plate 210, and the separator 230 with the adhesive layer 240 in this order. By changing the hot pressing conditions such as temperature, pressure, and pressure application time, the adhesion between the separator 230 and the electrode plate (positive electrode plate 210 and negative electrode plate 220) can be adjusted. The hot pressing conditions cannot be different between the interface between the separator 230 and the positive electrode plate 210 and the interface between the separator 230 and the negative electrode plate 220.

[0049] As the adhesive particles constituting the adhesive layer 240, a plurality of different adhesive particles may be used, but it is preferable to use the same adhesive particles in consideration of productivity, etc. That is, it is preferable that the same adhesive particles exist between the substrate 231 of the separator 230 and the positive electrode plate 210, and between the heat-resistant layer 232 of the separator 230 and the negative electrode plate 220. Here, the same adhesive particles refer to, for example, adhesive particles provided as the same product, and the production batches may be different.

[0050] The average particle size of the adhesive particles is, for example, about 0.1 μm to 1 μm, and preferably about 0.5 μm to 0.7 μm. The average particle size of the adhesive particles is measured by observing the surface of the separator 230 using a SEM, similarly to the average particle size of the inorganic particles constituting the heat-resistant layer 232 .

[0051] The adhesive particles of the adhesive layer 240 can melt or soften in the above-mentioned hot pressing process. By melting or softening the adhesive particles, the adhesive layer 240 is strongly adhered to the surfaces of the separator 230 and the electrode plates (positive plate 210 and negative plate 220), and good adhesion can be obtained. The adhesive layer 240 is, for example, composed of a resin with a glass transition temperature of 80°C or less. The adhesive layer 240 preferably includes an acrylic resin adhesive material, an epoxy resin adhesive material, a styrene-butadiene rubber adhesive material, a silicone rubber adhesive material, and a PVdF adhesive material. Among them, an acrylic resin adhesive material is more preferably used.

[0052] As described above, in the electrode body 200 , the mass of the binding particles per unit area at the interface between the negative electrode mixture layer of the negative electrode plate 220 and the heat-resistant layer 232 is greater than the mass of the binding particles per unit area at the interface between the positive electrode mixture layer of the positive electrode plate 210 and the substrate 231 .

[0053] In other words, the unit area weight of the adhesive layer 241 (first adhesive layer) provided between the positive electrode plate 210 and the separator 230 is smaller than the unit area weight of the adhesive layer 242 (second adhesive layer) provided between the negative electrode plate 220 and the separator 230. Figure 3 As shown, the weight per unit area of ​​the adhesive layer 241 (first adhesive layer) formed on the heat-resistant layer 232 (first surface) is smaller than the weight per unit area of ​​the adhesive layer 242 (second adhesive layer) formed on the base material 231 (second surface).

[0054] In the electrode body 200, the total weight per unit area of ​​the adhesive layer 241 (first adhesive layer) provided between the positive electrode plate 210 and the separator 230 and the weight per unit area of ​​the adhesive layer 242 (second adhesive layer) provided between the negative electrode plate 220 and the separator 230 is 0.03 g / m 2 Above and 0.15g / m 2Here, the weight per unit area of ​​the adhesive layer 241 (first adhesive layer) provided between the positive electrode plate 210 and the separator 230 is preferably 0.01 g / m 2 Above and 0.05g / m 2 Below left and right.

[0055] In the electrode assembly 200, the total weight per unit area of ​​the adhesive layer 240 on both sides of the separator 230 was set to 0.03 g / m 2 Above and 0.15g / m 2 The amount of the adhesive layer 240 can be made appropriate. More specifically, it is possible to prevent the adhesive force between the electrode plates (positive plate 210 and negative plate 220) and the separator 230 from becoming too strong. As a result, in the drying process in the manufacturing process of the square secondary battery 1, it is easy to ensure a gap between the positive plate 210 and the negative plate 220 as a path for discharging moisture, and it is possible to suppress the generation of gas caused by the reaction of residual moisture with the electrode active material, and the expansion of the battery case 100 caused by the gas.

[0056] In particular, by making the weight per unit area of ​​the adhesive layer 241 provided on the positive electrode plate 210 side relatively small, it is easy to ensure a gap that serves as a path for discharging water on the positive electrode plate 210 side. Therefore, it is possible to more effectively suppress the expansion of the battery case 100. In addition, by arranging the heat-resistant layer 232 having higher water permeability than the substrate 231 on the positive electrode plate 210 side, it is easier to ensure a path for discharging water on the positive electrode plate 210 side.

[0057] In addition, the mass of the bonding particles per unit area at the interface between the positive electrode mixture layer and the heat-resistant layer 232 can be calculated by measuring the number of bonding particles attached to the surface of the positive electrode mixture layer and the surface of the heat-resistant layer 232 and multiplying the total volume of the particles by the specific gravity of the particles. The mass of the bonding particles per unit area at the interface between the negative electrode mixture layer and the substrate 231 can also be calculated using the same method.

[0058] Figure 4 2 is a cross-sectional view showing the structure of an electrode body 200A according to a modified example. The electrode body 200A includes a positive electrode plate 210A, a negative electrode plate 220A, a separator 230A, and an adhesive layer 240A. Figure 5 It is a cross-sectional view showing the separator 230A and the adhesive layer 240A in the electrode body 200A.

[0059] like Figure 4 As shown, in the electrode body 200A, the unit area weight of the adhesive layer 241A provided between the positive electrode plate 210A and the separator 230A is smaller than the unit area weight of the adhesive layer 242A provided between the negative electrode plate 220A and the separator 230A. Figure 5As shown, the weight per unit area of ​​the adhesive layer 241A formed on the base material 231A is smaller than the weight per unit area of ​​the adhesive layer 242A formed on the heat-resistant layer 232A.

[0060] exist Figure 4 , Figure 5 In the modified example shown, the total weight per unit area of ​​the adhesive layers 240A on both sides of the separator 230A is also set to 0.03 g / m 2 Above and 0.15g / m 2 Therefore, the amount of the adhesive layer 240A becomes appropriate, and it is easy to ensure a gap that serves as a path for discharging water in the drying process.

[0061] Figure 6 to Figure 9 FIG. 2 is a top view showing an example of the configuration of the adhesive layer 240 on the diaphragm 230. The adhesive layer 240 may be Figure 6 As shown, it can be configured as a dot. Figure 7 As shown, it can also be configured as a strip. Figure 8 As shown, it can be configured on the entire surface, or as Fig. 9 The two sides of the diaphragm 230 may be configured in the same plane or in different planes. The thickness of the adhesive layer 240 on the two sides of the diaphragm 230 may be the same or different. From the perspective of ensuring a path for discharging water, the adhesive layer 240 is preferably locally configured on the diaphragm 230 ( Figure 6 , Figure 7 , Fig. 9 for example).

[0062] Fig.10 The graph shows the relationship between the ratio of the weight per unit area of ​​the adhesive layer 240 formed on both sides of the separator 230 in the electrode body 200 (positive electrode side / both sides) and the battery cell expansion rate (relative to the battery cell thickness in the standard state). Fig.10 The values ​​of the samples are shown.

[0063]

Table 1

[0064]

[0065] like Fig.10 As shown in Table 1, by making the ratio of the unit area weight on the positive electrode side less than 0.5, even if the unit area weight on the positive electrode side is smaller than the unit area weight on the negative electrode side, the expansion rate of the battery case 100 can be suppressed ( Fig.10 and “Battery cell thickness” in Table 1).

[0066] In addition, the present inventors confirmed that in Comparative Examples A to E shown in Table 2, the expansion rate of the battery case 100 was significantly increased compared to the results shown in Table 1. In addition, in Comparative Examples A to E, as shown in Table 2, Figure 4 , Figure 5 As shown, the base material 231A of the separator 230A is arranged on the positive electrode side, and the heat-resistant layer 232A is arranged on the negative electrode side.

[0067]

Table 2

[0068]

[0069] The main reason why the expansion rate of the battery case 100 is significantly increased in Comparative Examples A to E shown in Table 2 is that the unit area weight of the adhesive layer 240A is 0.5 g / m2 in total on both sides of the separator 230A. 2 The substrate 231A, which is larger than the heat-resistant layer 232A and has a less-easy-to-secure moisture discharge path, is disposed on the positive electrode side.

[0070] On the other hand, in Examples 1 to 11 shown in Table 1, it can be understood that since the total weight per unit area of ​​the adhesive layer 240 on both sides of the separator 230 is 0.15 g / m 2 The smaller the thickness, the smaller the weight per unit area on the positive electrode side, and the fact that the heat-resistant layer 232 which can more easily ensure a moisture discharge path than the substrate 231 is arranged on the positive electrode side can effectively suppress the expansion rate of the battery case 100.

[0071] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A battery, wherein: The battery comprises an electrode body, wherein the electrode body includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate. A first bonding layer is provided between the positive electrode plate and the separator, A second bonding layer is provided between the negative electrode plate and the separator, The mass of the adhesive particles contained in the first adhesive layer per unit area of ​​the adhesive surface, i.e., the unit area weight of the first adhesive layer, is smaller than the mass of the adhesive particles contained in the second adhesive layer per unit area of ​​the adhesive surface, i.e., the unit area weight of the second adhesive layer. The total weight per unit area of ​​the first adhesive layer and the weight per unit area of ​​the second adhesive layer is 0.03 g / m 2 Above and 0.15g / m 2 the following.

2. The battery according to claim 1, wherein The weight per unit area of ​​the first adhesive layer is 0.01 g / m 2 Above and 0.05g / m 2 the following.

3. The battery according to claim 1 or 2, wherein: The separator includes a resin substrate and a heat-resistant layer provided on the substrate, wherein the heat-resistant layer includes inorganic particles and a binder. The heat-resistant layer and the positive electrode plate face each other via the first adhesive layer. The substrate and the negative electrode plate face each other with the second adhesive layer interposed therebetween.

4. The battery according to claim 1 or 2, wherein The positive electrode plate has a positive electrode mixture layer containing a lithium transition metal composite oxide.

5. The battery according to claim 1 or 2, wherein The first adhesive layer and the second adhesive layer include at least one adhesive material selected from the group consisting of an acrylic resin adhesive material, an epoxy resin adhesive material, a styrene-butadiene rubber adhesive material, a silicone rubber adhesive material, and a PVdF adhesive material.

6. A method for manufacturing a battery, wherein: The battery manufacturing method comprises a step of forming an electrode body, wherein the electrode body includes a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate and having a first surface facing the positive electrode plate and a second surface facing the negative electrode plate. The process of forming the electrode body includes: forming a first adhesive layer on the first surface of the diaphragm, and forming a second adhesive layer on the second surface of the diaphragm; bonding the separator to the positive electrode plate via the first bonding layer; and The separator is bonded to the negative electrode plate via the second bonding layer, The mass of the adhesive particles contained in the first adhesive layer per unit area of ​​the adhesive surface, i.e., the unit area weight of the first adhesive layer, is smaller than the mass of the adhesive particles contained in the second adhesive layer per unit area of ​​the adhesive surface, i.e., the unit area weight of the second adhesive layer. The total weight per unit area of ​​the first adhesive layer and the weight per unit area of ​​the second adhesive layer is 0.03 g / m 2 Above and 0.15g / m 2 the following.

7. The method for manufacturing a battery according to claim 6, wherein: The weight per unit area of ​​the first adhesive layer is 0.01 g / m 2 Above and 0.05g / m 2 the following.

8. The method for manufacturing a battery according to claim 6 or 7, wherein: The separator includes a resin substrate and a heat-resistant layer provided on the substrate, wherein the heat-resistant layer includes inorganic particles and a binder. The process of forming the electrode body includes: bonding the heat-resistant layer to the positive electrode plate via the first bonding layer; and The substrate and the negative electrode plate are bonded to each other via the second bonding layer.

9. The method for manufacturing a battery according to claim 6 or 7, wherein: The positive electrode plate has a positive electrode mixture layer containing a lithium transition metal composite oxide.

10. The method for manufacturing a battery according to claim 6 or 7, wherein: The first adhesive layer and the second adhesive layer include at least one adhesive material selected from the group consisting of an acrylic resin adhesive material, an epoxy resin adhesive material, a styrene-butadiene rubber adhesive material, a silicone rubber adhesive material, and a PVdF adhesive material.

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