Battery

Abstract

The invention provides a battery. In the present disclosure, there is provided a battery having an electrode body having a first surface and a second surface facing the first surface in the thickness direction, and a laminated exterior body covering the electrode body, the battery has a first buffer member between the first surface and the laminated exterior body facing the first surface in the thickness direction, and the first buffer member contains a polyurea resin, thereby solving the above problem.

Description

Technical Field

[0001] The present disclosure relates to batteries. Background Art

[0002] Batteries such as lithium-ion secondary batteries generally have an electrode body having a positive electrode collector, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode collector. The electrode body is, for example, enclosed in an internal space surrounded by a packaging material. Japanese Patent Application Laid-Open No. 2020-170583 discloses a laminated secondary battery having a laminated electrode body, a soft laminated outer body, and a hard laminated outer body. Summary of the invention

[0003] When the active material expands and contracts due to charge and discharge, the volume of the electrode body also changes with the expansion and contraction. If the volume change of the electrode body is large, the stress applied from the electrode body to the laminated outer package also changes, so the sealing property of the laminated outer package is likely to decrease.

[0004] The present disclosure has been made in view of the above-mentioned actual situation, and a main object of the present disclosure is to provide a battery in which the volume change of an electrode body accompanying charge and discharge is suppressed. 1 A battery comprising an electrode body and a laminated outer casing covering the electrode body, wherein: The electrode body has a first surface and a second surface, the second surface being opposite to the first surface in the thickness direction, The battery includes a first cushioning member between the first surface and the laminated exterior body facing the first surface in the thickness direction, wherein the first cushioning member contains a polyurea resin. 2 The battery according to item 1, wherein: The battery includes a second cushioning member between the second surface and the laminated exterior body that faces the second surface in the thickness direction, and the second cushioning member contains a polyurea resin. 3 The battery according to 2, wherein: The battery has a third buffer member, which is disposed on the side of the electrode body and contains a polyurea resin. The first buffer member, the second buffer member, and the third buffer member are integrated. 4 The battery according to any one of 1 to 3, wherein The electrode body comprises a positive electrode active material layer, a negative electrode active material layer and an electrolyte layer, wherein the electrolyte layer is disposed between the positive electrode active material layer and the negative electrode active material layer. The negative electrode active material layer contains a Si-based active material as a negative electrode active material. 5 The battery according to any one of 1 to 4, wherein The electrode body comprises a positive electrode active material layer, a negative electrode active material layer and an electrolyte layer, wherein the electrolyte layer is disposed between the positive electrode active material layer and the negative electrode active material layer. The electrolyte layer is a solid electrolyte layer containing a solid electrolyte.

[0010] The battery of the present disclosure has an effect of being able to suppress the volume change of the electrode body accompanying charge and discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like symbols represent like elements, and in which: Figure 1A is a schematic top view illustrating a battery in the present disclosure; Figure 1B is a schematic cross-sectional view illustrating a battery in the present disclosure; Figure 2 is a schematic perspective view illustrating an electrode body in the present disclosure; Figure 3A is a schematic cross-sectional view illustrating a battery in the present disclosure; Figure 3B is a schematic cross-sectional view illustrating a battery in the present disclosure; Figure 4A is a schematic cross-sectional view illustrating an electrode body in the present disclosure; Figure 4B is a schematic cross-sectional view illustrating an electrode body in the present disclosure; Figure 5 These are the results of a restraint pressure variation test on the batteries obtained in Examples 1 to 3 and Comparative Example 1. DETAILED DESCRIPTION

[0012] Hereinafter, the battery in the present disclosure will be described in detail using the accompanying drawings. The figures shown below are schematically represented, and the size and shape of each part are appropriately exaggerated for easy understanding. In addition, in this specification, when expressing the manner in which other components are configured relative to a certain component, when it is only expressed as "above" or "below", unless otherwise specified, both Case 1 and Case 2 are included. Case 1 is a situation in which other components are configured directly above or below a certain component in a manner of contacting the certain component. Case 2 is a situation in which other components are configured above or below a certain component through other components.

[0013] Figure 1A is a schematic top view illustrating a battery in the present disclosure, Figure 1B yes Figure 1A IB-IB cross-sectional view. Figure 1A , Figure 1B The battery 100 shown has an electrode body 10, a laminated outer body 20 covering the electrode body 10, and a terminal 30 electrically connected to the electrode body 10. The electrode body 10 has a first surface S1, a second surface S2 opposite to the first surface S1 in the thickness direction (z direction), and a plurality of third surfaces S3 corresponding to side surfaces connecting the first surface S1 and the second surface S2. In addition, the battery 100 has a first buffer member 40a containing a polyurea resin at least between the first surface S1 and the laminated outer body 20. In addition, as shown Figure 1B As shown, the cushioning members (the first cushioning member 40 a , the second cushioning member 40 b , and the third cushioning member 40 c ) containing the polyurea resin may be arranged so as to cover the first surface S1 , the second surface S2 , and the third surface S3 .

[0014] According to the present disclosure, by configuring a buffer member containing a polyurea resin between the electrode body and the laminated outer body, a battery is formed that suppresses the volume change of the electrode body accompanying charging and discharging. As described above, when the active material expands and contracts due to charging and discharging, the volume of the electrode body also changes with the expansion and contraction. If the volume change of the electrode body is large, the stress applied from the electrode body to the laminated outer body also changes, so the sealing of the laminated outer body is easily reduced.

[0015] In contrast, in the present disclosure, a buffer member containing a polyurea resin is disposed between the electrode body and the laminated outer body. Polyurea resin has excellent properties such as high elongation, high elasticity, high strength, and high adhesion. Therefore, by disposing a buffer member containing a polyurea resin between the electrode body and the laminated outer body, even if the volume of the electrode body changes due to charging and discharging, the buffer member absorbs the volume change. By absorbing the volume change by the buffer member, the stress applied to the laminated outer body from the electrode body can be reduced. In addition, polyurea resin has the advantages of high chemical resistance, corrosion resistance, flame retardancy, water resistance, heat resistance, and wear resistance. Moreover, when making a buffer member containing a polyurea resin, for example, spraying is used. In this case, it has the advantages of being easy to apply to a large area, curing in about a few minutes, and thus having good workability.

[0016] 1. Battery structure

[0017] The battery in the present disclosure has at least an electrode body, a laminated exterior body, and a buffer member.

[0018] (1) Electrode body

[0019] The electrode body in the present disclosure functions as a power generation component of the battery. The shape of the electrode body is not particularly limited, for example, Figure 2As shown, it has a first surface S1, a second surface S2 opposite to the first surface S1, and a plurality of third surfaces S3 corresponding to the side surfaces connecting the first surface S1 and the second surface S2. Figure 2 The description of the tabs for connecting to the terminals is omitted. The first surface S1 and the second surface S2 both correspond to the main surfaces of the electrode body, and the normal direction of the main surfaces is defined as the thickness direction (z direction).

[0020] The plan view shape of the first surface is not particularly limited, and examples thereof include quadrilaterals such as a square, a rectangle, a rhombus, a trapezoid, and a parallelogram. Figure 2 The top view shape of the first surface S1 in the embodiment is a rectangle. The shape of the first surface may be a polygon other than a quadrilateral, or a shape having a curve such as a circle. In addition, the top view shape of the second surface is the same as the shape of the first surface. The top view shape of the third surface is not particularly limited, and examples thereof include quadrilaterals such as a square, a rectangle, a rhombus, a trapezoid, and a parallelogram.

[0021] (2) Buffer components

[0022] The cushioning member in the present disclosure contains a polyurea resin and is disposed between the electrode body and the laminated exterior body.

[0023] like Figure 3A As shown, a first buffer member 40a may be disposed between the first surface S1 of the electrode body 10 and the laminated outer casing 20 facing the first surface S1. By disposing the first buffer member 40a, the volume change of the electrode body accompanying charge and discharge can be suppressed in the thickness direction (z direction). Figure 3A In the embodiment, no buffer member is disposed between the second surface S2 of the electrode assembly 10 and the laminated exterior body 20 facing the second surface S2.

[0024] like Figure 3B As shown in FIG. 1 , the first buffer member 40a may be disposed between the first surface S1 of the electrode body 10 and the laminated outer casing 20 facing the first surface S1. Figure 3B As shown, a second buffer member 40b may be arranged between the second surface S2 of the electrode body 10 and the laminated outer casing 20 opposite to the second surface S2. By arranging the first buffer member 40a and the second buffer member 40b, the volume change of the electrode body accompanying charge and discharge can be further suppressed in the thickness direction (z direction). Figure 3B In the embodiment, the first buffer member 40a and the second buffer member 40b are separate bodies.

[0025] like Figure 1B As shown in FIG. 1 , the first buffer member 40a may be disposed between the first surface S1 of the electrode body 10 and the laminated outer casing 20 facing the first surface S1. Figure 1BAs shown in FIG. 1 , a second buffer member 40 b may be disposed between the second surface S2 of the electrode body 10 and the laminated outer casing 20 facing the second surface S2. Figure 1B As shown in FIG. 1 , a third buffer member 40 c may be disposed between the third surface S3 of the electrode body 10 and the laminated outer casing 20 facing the third surface S3. Figure 1B In the embodiment, the first buffer member 40a, the second buffer member 40b and the third buffer member 40c are integrated. In addition, the third buffer member 40c is connected to the first buffer member 40a and the second buffer member 40b, so that the volume change of the electrode body accompanying charge and discharge can be significantly suppressed in the thickness direction (z direction).

[0026] exist Figure 1A , Figure 1B In the figure, the two third buffer members 40c are opposite to each other in the y direction orthogonal to the extension direction (x direction) of the terminal 30. On the other hand, although not specifically shown in the figure, the two third buffer members may also be opposite to each other in the x direction. In addition, in the present disclosure, an integrated buffer member may be configured in a manner that covers the entire surface of the electrode body. In addition, the buffer member may be tightly fitted or not, but the former is preferred. This is because, in the thickness direction (z direction), the volume change of the electrode body accompanying charging and discharging can be further suppressed. In particular, the buffer member is preferably a member formed on the surface of the electrode body by spraying. This is because the buffer member and the electrode body have excellent adhesion.

[0027] (3) Laminated outer body

[0028] The laminated outer casing in the present disclosure is arranged so as to cover the electrode body via the buffer member. Figure 1B As shown, the electrode body 10 is sealed by welding the opposed laminated outer packaging bodies 20 to each other to form a sealing portion α. ​​In addition, although not specifically shown in the figure, the sealing portion may also be folded. By folding the sealing portion α, the sealing property is improved. In addition, Figure 1B In the embodiment, two laminated outer casings 20 are used to seal the electrode body 10. On the other hand, although not particularly shown in the figure, the electrode body can also be sealed by bending one laminated outer casing. As a method for fusing the laminated outer casings to each other, for example, a method of pressing a heating rod on the overlapping portions of the laminated outer casings to heat-fuse the laminated outer casings to each other can be cited.

[0029] 2. Battery components

[0030] The battery in the present disclosure has at least an electrode body, a laminated exterior body, and a buffer member.

[0031] (1) Buffer components

[0032] The cushioning member in the present disclosure contains a polyurea resin. The polyurea resin is a resin having a urea bond (-NH-CO-NH-). Examples of the polyurea resin include polyurea and polyurea polyurethane, of which polyurea is preferred. Polyurea is generally a resin that does not have a urethane bond (-NH-CO-O-), and has the advantage of being less susceptible to hydrolysis than polyurea polyurethane.

[0033] Polyurea is generally obtained by reacting polyisocyanate with polyamine. Among them, polyurea is preferably a resin using only polyisocyanate and polyamine as resin raw materials.

[0034] Polyisocyanate is a compound having two or more isocyanate groups in one molecule. Examples of polyisocyanate include diphenylmethane-4,4'-diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, polymethylene polyphenyl isocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate.

[0035] Polyamines are compounds having two or more amino groups (primary or secondary) in one molecule. Examples of polyamines include alkylamines, aromatic amines, polyetheramines, and vinylamines. Examples of alkylamines include ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, 1,3-butylenediamine, 1,2-butylenediamine, 1,5-pentanediamine, 1,6-hexanediamine, and dimer diamine. Examples of aromatic amines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, 1,5-naphthalenediamine, 1,8-naphthalenediamine, o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine. Examples of polyetheramines include triethylene glycol diamine, trimethylolpropane poly(oxypropylene) triamine, and methoxy poly(oxyethylene / oxypropylene)-2-propylamine. Examples of vinylamines include diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. The molecular weight of the polyamine is not particularly limited, but is, for example, 50 g / mol or more and 1000 g / mol or less.

[0036] When synthesizing polyurea, additives such as a chain extender, a crosslinking agent, and a catalyst may be used. Examples of the chain extender include amine-based chain extenders.

[0037] On the other hand, polyurea polyurethane may be, for example, a resin obtained by polymerizing polyisocyanate, polyamine, and a polyol-based chain extender. Polyurea polyurethane may be, for example, a resin obtained by polymerizing polyisocyanate, polyol, and an amine-based chain extender.

[0038] The glass transition temperature of the polyurea resin is not particularly limited, and is, for example, greater than -50°C and less than 250°C. In addition, the buffer member preferably contains a polyurea resin as a main component, and more preferably contains only a polyurea resin as a resin component. The elastic modulus of the resin member is not particularly limited, and is, for example, greater than 5 MPa and less than 30 MPa, and may be greater than 8 MPa and less than 15 MPa. In addition, the breaking strength of the resin member is, for example, greater than 30 kN / m at 25°C, and may be greater than 40 kN / m. On the other hand, the breaking strength of the resin member is, for example, less than 100 kN / m at 25°C. In addition, the breaking strength of the resin member is, for example, greater than 80 kN / m at -25°C, and may be greater than 100 kN / m. On the other hand, the breaking strength of the resin member is, for example, less than 200 kN / m at -25°C. In addition, the thickness of the buffer member is not particularly limited, and is, for example, greater than 0.5 mm and less than 5 mm, and may be greater than 0.8 mm and less than 3 mm.

[0039] (2) Electrode body

[0040] The electrode body in the present disclosure generally has a positive electrode current collector, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode current collector in this order in the thickness direction. Figure 4A , Figure 4B This is a schematic cross-sectional view illustrating an electrode body in the present disclosure, which is equivalent to Figure 2 A schematic cross-sectional view of the electrode body in the xz plane.

[0041] Figure 4A The electrode body 10 shown has a negative electrode collector 1, a negative electrode active material layer 2, an electrolyte layer 3, a positive electrode active material layer 4, and a positive electrode collector 5 in order in the thickness direction (z direction). In addition, the negative electrode collector 1 has a negative electrode tab 1t for connecting to a negative electrode terminal (not shown), and the positive electrode collector 5 has a positive electrode tab 5t for connecting to a positive electrode terminal (not shown).

[0042] Figure 4B The electrode body 10 shown includes a negative electrode current collector 1 and a negative electrode active material layer 2x, an electrolyte layer 3x, a positive electrode active material layer 4x, and a positive electrode current collector 5x arranged in order from one surface of the negative electrode current collector 1 in the thickness direction (z direction). Figure 4B The electrode body 10 shown includes a negative electrode active material layer 2 y , an electrolyte layer 3 y , a positive electrode active material layer 4 y , and a positive electrode collector 5 y which are arranged in order from the other surface of the negative electrode collector 1 in the thickness direction (z direction).

[0043] The positive electrode active material layer contains at least a positive electrode active material. The positive electrode active material layer may further contain at least one of an electrolyte, a conductive material, and a binder. Examples of the positive electrode active material include oxide active materials. Examples of the oxide active material include LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2、LiNi 0.8 Co 0.15 Al 0.05 O2 and other rock salt layered active materials, LiMn2O4 and other spinel active materials, LiFePO4 and other olivine active materials. In addition, sulfur (S) can also be used as the positive electrode active material. The shape of the positive electrode active material is, for example, a particle shape.

[0044] The electrolyte may be a solid electrolyte or a liquid electrolyte. The solid electrolyte may be an organic solid electrolyte such as a gel electrolyte, or an inorganic solid electrolyte such as a sulfide solid electrolyte or an oxide solid electrolyte. Among them, the solid electrolyte is preferably a sulfide solid electrolyte. This is because the ion conductivity is high.

[0045] The sulfide solid electrolyte usually contains at least Li and S. The sulfide solid electrolyte preferably further contains M element (M is at least one of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In). In addition, the sulfide solid electrolyte may also contain halogen elements such as F, Cl, Br, and I.

[0046] The sulfide solid electrolyte may be a glass-based (amorphous) sulfide solid electrolyte, a glass-ceramic sulfide solid electrolyte, or a crystalline sulfide solid electrolyte. The sulfide solid electrolyte may have a crystalline phase. Examples of the crystalline phase include a Thio-LISICON type crystalline phase, an Argentum type crystalline phase, and an LGPS type crystalline phase.

[0047] The composition of the sulfide solid electrolyte may be, for example, xLi2S·(1-x)P2S5 (0.5≤x<1), yLiI·zLiBr·(100-yz) (xLi2S·(1-x)P2S5) (0.5≤x<1, 0≤y≤30, 0≤z≤30). However, the composition of the sulfide solid electrolyte is not particularly limited. In these compositions, x preferably satisfies 0.7≤x≤0.8. In addition, as other examples of the composition of the sulfide solid electrolyte, Li 7-x-2y PS 6-x-y X y X is at least one of F, Cl, Br, and I, and x and y satisfy 0≤x, 0≤y. In addition, as another example of the composition of the sulfide solid electrolyte, Li 4-x M1-x P x S4 (0<x<1). M is at least one of Al, Zn, In, Ge, Si, Sn, Sb, Ga and Bi.

[0048] On the other hand, the liquid electrolyte (electrolyte) contains, for example, a supporting electrolyte such as LiPF6 and a solvent such as a carbonate solvent. In addition, as a conductive material, for example, a carbon material can be cited. In addition, as an adhesive, for example, a rubber adhesive and a fluoride adhesive can be cited.

[0049] The negative electrode active material layer contains at least a negative electrode active material. The negative electrode active material layer may further contain at least one of an electrolyte, a conductive material, and a binder. Examples of the negative electrode active material include metal active materials such as Li, Si, and Sn, carbon active materials such as graphite, and Li4Ti5O 12 Oxidant active substances.

[0050] The negative electrode active material is preferably a Si-based active material. This is because it can achieve a high capacity of the battery. In addition, the volume change of the Si-based active material based on charging and discharging is large, but by using the above-mentioned buffer member, a battery in which the volume change of the electrode body accompanying charging and discharging is suppressed can be obtained. The Si-based active material is an active material with Si as the main component. The Si-based active material can be a Si single substance, a Si alloy, or a Si oxide. In addition, the Si-based active material can have a diamond-type crystal phase, a type I crystal phase, or a type II crystal phase. In the crystal phase of the inclusion compound type I or type II, a polyhedron (cage) containing pentagons or hexagons is formed by multiple Si elements. The polyhedron has a space inside that can accommodate metal ions such as Li ions, so that the volume change caused by charging and discharging can be suppressed.

[0051] The shape of the negative electrode active material is, for example, particle or foil. The electrolyte, conductive material and binder are the same as those described above.

[0052] The electrolyte layer is disposed between the positive electrode active material layer and the negative electrode active material layer, and contains at least an electrolyte. The electrolyte may be a solid electrolyte or a liquid electrolyte. The electrolyte is the same as described above. The electrolyte layer may be a solid electrolyte layer containing a solid electrolyte. Furthermore, the solid electrolyte is preferably a sulfide solid electrolyte. In addition, generally, a battery having a solid electrolyte layer containing an inorganic solid electrolyte is referred to as a fully solid-state battery.

[0053] The positive electrode current collector collects current from the positive electrode active material layer. Examples of materials for the positive electrode current collector include metals such as aluminum, SUS, and nickel. Examples of shapes for the positive electrode current collector include foil and mesh. The positive electrode current collector generally has a positive electrode tab for connecting to a positive electrode terminal.

[0054] The negative electrode current collector collects current from the negative electrode active material layer. Examples of the material of the negative electrode current collector include metals such as copper, SUS, and nickel. Examples of the shape of the negative electrode current collector include foil and mesh. The negative electrode current collector generally has a negative electrode tab for connecting to the negative electrode terminal.

[0055] (3) Laminated outer body

[0056] The laminated outer body in the present disclosure has a structure in which at least an inner resin layer and a metal layer are laminated. In addition, the laminated outer body may also have an inner resin layer, a metal layer and an outer resin layer in sequence along the thickness direction. As the material of the inner resin layer, for example, olefin resins such as polypropylene (PP) and polyethylene (PE) can be cited. As the material of the metal layer, for example, aluminum, aluminum alloy, and stainless steel can be cited. As the material of the outer resin layer, for example, polyethylene terephthalate (PET) and nylon can be cited. The thickness of the inner resin layer is, for example, greater than 40 μm and less than 100 μm. The thickness of the metal layer is, for example, greater than 30 μm and less than 60 μm. The thickness of the outer resin layer is, for example, greater than 20 μm and less than 60 μm. The thickness of the laminated outer body is, for example, greater than 80 μm and less than 250 μm.

[0057] (4) Battery

[0058] like Figure 1A , Figure 1B As shown, the battery 100 has terminals 30 (positive terminal 30a, negative terminal 30b) electrically connected to the electrode body 10. One end of the positive terminal 30a is electrically connected to the positive electrode tab (not shown) in the electrode body 10 inside the laminated outer body 20, and the other end of the positive terminal 30a is exposed outside the laminated outer body 20. Similarly, one end of the negative terminal 30b is electrically connected to the negative electrode tab (not shown) in the electrode body 10 inside the laminated outer body 20, and the other end of the negative terminal 30b is exposed outside the laminated outer body 20. Examples of the material of the terminal include metals such as SUS.

[0059] The battery in the present disclosure is typically a lithium-ion secondary battery. As the use of the battery, for example, a power source for a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a pure electric vehicle (BEV), a gasoline vehicle, a diesel vehicle, etc. can be cited. It is particularly preferably used as a driving power source for a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV) or a pure electric vehicle (BEV). In addition, the battery in the present disclosure can be used as a power source for a mobile body other than a vehicle (such as a railway, a ship, an aircraft), and can also be used as a power source for electrical products such as an information processing device.

[0060] The present disclosure is not limited to the above-mentioned embodiments. The above-mentioned embodiments are illustrative, and any technical concept having substantially the same structure and achieving the same function and effect as the technical concept described in the claims of the present disclosure is included in the technical scope of the present disclosure.

[0061] Example 1

[0062] Electrode body fabrication

[0063] The positive electrode active material, sulfide solid electrolyte, conductive material and binder were weighed in a ratio of positive electrode active material: sulfide solid electrolyte: conductive material: binder = 88.2:9.8:1.3:0.7. The positive electrode active material is LiNi 0.8 Co 0.15 Al 0.05 O2. The sulfide solid electrolyte is a Li2S-P2S5 sulfide solid electrolyte. The conductive material is vapor-grown carbon fiber. The binder is a PVdF binder. Next, these materials are stirred together with a dispersion medium (butyl butyrate) by an ultrasonic dispersion device to prepare a positive electrode slurry. Next, the obtained positive electrode slurry is applied to a positive electrode collector (Al foil) by a doctor blade method and dried on a hot plate at 100°C for 30 minutes. Thus, a positive electrode having a positive electrode collector and a positive electrode active material layer is obtained.

[0064] Then, the negative electrode active material, sulfide solid electrolyte, conductive material and binder are weighed in the manner of negative electrode active material: sulfide solid electrolyte: conductive material: binder = 100:77.6:2:15. The negative electrode active material is Si powder. The sulfide solid electrolyte is a Li2S-P2S5 sulfide solid electrolyte. The conductive material is vapor-grown carbon fiber. The binder is a PVdF-based binder. Then, these materials are stirred together with a dispersion medium (butyl butyrate) by an ultrasonic dispersion device to prepare a negative electrode slurry. Then, the obtained negative electrode slurry is applied to the negative electrode collector (Ni foil) by a doctor blade method and dried on a hot plate at 100°C for 30 minutes. Thus, a negative electrode having a negative electrode collector and a negative electrode active material layer is obtained.

[0065] Then, the sulfide solid electrolyte (Li2S-P2S5 system sulfide solid electrolyte) and the binder (PVdF system binder) were weighed in a ratio of sulfide solid electrolyte: binder = 99.4:0.4. Then, these materials were stirred together with the dispersion medium (butyl butyrate) by an ultrasonic dispersion device to prepare a slurry for the solid electrolyte layer. Then, the obtained slurry was applied to the substrate (SUS foil) by a scraper method and dried on a hot plate at 100°C for 30 minutes. Thus, a transfer member having a substrate and a solid electrolyte layer was obtained.

[0066] Then, the negative electrode and the transfer member were stacked in such a manner that the negative electrode active material layer and the solid electrolyte layer faced each other, and pressed using a roller press at 50 kN / cm and 160°C. The substrate (SUS foil) was peeled off from the pressed laminate. The exposed solid electrolyte layer was made to face the positive electrode active material layer in the positive electrode, and pressed using a roller press at 20 kN / cm and 160°C. Thus, an electrode body was obtained.

[0067] Battery production

[0068] The positive terminal and the negative terminal were installed on the electrode body, and polyurea (elastic modulus: 13.7 MPa) was sprayed on the two main surfaces (first surface and second surface) of the electrode body to form the first buffer member and the second buffer member. The thickness of each of them was 1 mm. Then, the electrode body, the first buffer member and the second buffer member were sealed with a laminated outer body (aluminum laminate) to obtain a battery.

[0069] Example 2

[0070] A battery was obtained in the same manner as in Example 1 except that the buffer member was formed so as to cover the entire surface of the electrode body.

[0071] Example 3

[0072] A battery was obtained in the same manner as in Example 1 except that a polyurea plate (elastic modulus: 13.7 MPa) having a thickness of 1 mm was disposed on each of the two main surfaces (the first surface and the second surface) of the electrode body.

[0073] Comparative Example 1

[0074] A battery was obtained in the same manner as in Example 1 except that the first and second buffer members were not formed.

[0075] evaluate

[0076] The batteries obtained in Examples 1-3 and Comparative Example 1 were sandwiched between two restraining plates and fastened with a restraining pressure of 5 MPa by means of a connection to fix the distance between the two restraining plates. Next, they were charged at a constant current of 1 / 10 C to 4.05 V, and then at a constant voltage of 4.05 V to a final current of 1 / 100 C, and the restraining pressure change during charging was measured. The results are shown in Figure 5 .like Figure 5 As shown, it was confirmed that Examples 1 to 3 had smaller changes in restraint pressure than Comparative Example 1. In addition, Example 1 had smaller changes in restraint pressure than Example 3, and Example 2 had smaller changes in restraint pressure than Example 1. Thus, it was confirmed that the volume change of the electrode body accompanying charge and discharge can be suppressed by arranging a buffer member containing a polyurea resin between the electrode body and the laminated outer casing.

Claims

1. A battery comprising an electrode body and a laminated outer body covering the electrode body, wherein: The electrode body has a first surface and a second surface, the second surface being opposite to the first surface in the thickness direction, The battery includes a first cushioning member between the first surface and the laminated exterior body that faces the first surface in the thickness direction, and the first cushioning member contains a polyurea resin.

2. The battery according to claim 1, wherein The battery includes a second cushioning member between the second surface and the laminated exterior body that faces the second surface in the thickness direction, and the second cushioning member contains a polyurea resin.

3. The battery according to claim 2, wherein The battery includes a third buffer member, which is disposed on a side surface of the electrode body and contains a polyurea resin. The first buffer member, the second buffer member, and the third buffer member are integrated.

4. The battery according to claim 1, wherein The electrode body comprises a positive electrode active material layer, a negative electrode active material layer and an electrolyte layer, wherein the electrolyte layer is arranged between the positive electrode active material layer and the negative electrode active material layer. The negative electrode active material layer contains a Si-based active material as a negative electrode active material.

5. The battery according to claim 1, wherein The electrode body comprises a positive electrode active material layer, a negative electrode active material layer and an electrolyte layer, wherein the electrolyte layer is arranged between the positive electrode active material layer and the negative electrode active material layer. The electrolyte layer is a solid electrolyte layer containing a solid electrolyte.

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