Battery and module

Abstract

To provide a battery in which the occurrence of a short circuit in an electrode assembly is suppressed.SOLUTION: A battery according to the present disclosure includes an electrode assembly and a laminated exterior housing that houses the electrode assembly. The electrode assembly is formed by alternately stacking positive and negative electrode bodies with separators interposed therebetween. The laminated exterior housing includes an electrically insulating hard layer on at least one surface facing the electrode assembly.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to batteries and modules.

Background Art

[0002] Patent Document 1 discloses a lithium secondary battery (hereinafter also referred to as a "battery"). The battery includes an electrode assembly (hereinafter also referred to as an "electrode body") and a case (hereinafter also referred to as an "outer package") that houses the electrode body. The outer package is made of a multilayer laminate sheet. The laminate includes an insulating layer having an elongation rate of 10% or more. The "elongation rate" indicates the deformation rate of an object broken during a test with respect to its non-test state. As materials for the insulating layer, polyurethane-based resins, epoxy resins, fluorine-based resins, polyimide-based resins, polyester-based resins, and polyolefin-based resins are disclosed. In this battery, when a physical force is applied from an external conductive object (for example, a nail), the insulating layer extends in a shape that wraps around the electrode body. Thereby, the insulating layer suppresses the occurrence of direct contact between the external conductive object and the electrode body, and also suppresses the occurrence of direct contact between the positive electrode and the negative electrode included in the electrode body. As a result, the occurrence of abnormal heat generation in the battery is suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] During the battery manufacturing process, foreign matter (e.g., metal powder during ultrasonic bonding of the current collector and tab, etc.) may adhere to the outer surface of the laminate exterior. When a plurality of batteries are housed in a metal case to form a module, foreign matter (e.g., cutting chips of the metal case, etc.) may adhere to the outer surface of the laminate exterior. In the battery disclosed in Patent Document 1, foreign matter easily penetrates the insulating layer. As a result, the foreign matter may short-circuit the electrode body. As a result, there is a risk of abnormal heat generation in the battery.

[0005] The present disclosure has been made in view of the above circumstances. The problem to be solved by one embodiment of the present disclosure is to provide a battery and a module in which the occurrence of short-circuiting of the electrode body is suppressed.

Means for Solving the Problem

[0006] The means for solving the above problem includes the following embodiments.

[0007] <1>The battery according to the first aspect of the present disclosure is an electrode body in which a positive electrode body and a negative electrode body are alternately laminated with a separator interposed therebetween, a laminate exterior that houses the electrode body, and the laminate exterior includes a hard layer in a portion overlapping the electrode body when viewed from the thickness direction of the electrode body, and is a battery.

[0008] The "laminate exterior" refers to a case made of a laminate sheet. The "laminate sheet" refers to a sheet having a metal layer, a first resin layer laminated on one main surface of the metal layer, and a second resin layer laminated on the other main surface of the metal layer. The "hard layer" refers to a layer harder than aluminum. Specifically, it refers to a layer having a Mohs hardness of 3.0 or more. In other words, the elongation rate of the hard layer is less than 10%.

[0009] In the battery manufacturing process, foreign matter (e.g., metal powder during ultrasonic bonding of the current collector and tab) may adhere to the outer surface of the laminate exterior. When a plurality of batteries are housed in a metal case to form a module, foreign matter (e.g., cutting chips of the metal case) may adhere to the outer surface of the laminate exterior. In the first aspect, the laminate exterior includes a hard layer in a portion overlapping the electrode body when viewed in the thickness direction of the electrode body. Foreign matter is difficult to penetrate the hard layer. As a result, foreign matter is less likely to penetrate into the interior of the laminate exterior than in a configuration where the laminate exterior does not include a hard layer. Consequently, in the battery of the first aspect, the occurrence of a short circuit in the electrode body is suppressed.

[0010] <2>The battery of the second aspect of the present disclosure is the battery according to <1>, wherein the hard layer has electrical insulation.

[0011] "The hard layer having electrical insulation" refers to a hard layer having an electrical resistance of 10 10 Ω·m or more.

[0012] In the battery of the second aspect, the occurrence of a short circuit in the electrode body is further suppressed.

[0013] <3>The battery of the third aspect of the present disclosure is the battery according to <1> or <2>, wherein the hard layer contains at least one of ceramics and glass.

[0014] In the third aspect, the Mohs hardness of the hard layer is relatively high. As a result, in the battery of the third aspect, the occurrence of a short circuit in the electrode body is further suppressed.

[0015] <4>The battery of the fourth aspect of the present disclosure is wherein the laminate exterior is flat, and the surface on the electrode body side includes the surfaces on the electrode body side of both main surfaces of the laminate exterior, and is the battery according to any one of <1> to <3>.

[0016] In the fourth aspect, foreign matter is less likely to enter the inside of the laminated exterior body than in a configuration where no hard layer is formed on the electrode body side surfaces of both main surfaces of the laminated exterior body. As a result, in the battery of the fourth aspect, the occurrence of a short circuit in the electrode body is more suppressed.

[0017] <5>The module according to the fifth aspect of the present disclosure is a plurality of batteries according to any one of <1> to <4> above, and a metal case that houses the plurality of batteries, and is a module.

[0018] In the module of the fifth aspect, the occurrence of a short circuit in the electrode body is suppressed.

Advantages of the Invention

[0019] According to the present disclosure, a battery and a module in which the occurrence of a short circuit in the electrode body is suppressed are provided.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples are illustrative of the embodiments and do not limit the scope of the embodiments. In the present disclosure, a combination of two or more preferred aspects is a more preferred aspect. In the present disclosure, a numerical range represented using "~" means a range including the numerical values described before and after "~" as the lower limit value and the upper limit value. In a numerical range described stepwise in the present disclosure, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of the numerical range described in other stepwise descriptions. In the numerical range described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0022] Hereinafter, embodiments of the battery and the module of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and the description will not be repeated.

[0023] (1.1) Module As shown in FIGS. 1 and 2, a module 1 according to an embodiment of the present disclosure includes a plurality of batteries 2 and a metal case 10. The metal case 10 houses the plurality of batteries 2. The module 1 is a rectangular parallelepiped.

[0024] In the present embodiment, the thickness direction of the module 1 is defined as the X-axis direction, the longitudinal direction of the module 1 is defined as the Y-axis direction, and the short-side direction of the module 1 is defined as the Z-axis direction. Each of the X-axis, the Y-axis, and the Z-axis is perpendicular to each other. Note that these directions do not limit the directions during use of the battery and the module of the present disclosure.

[0025] The length L10 in the Y-axis direction of the module 1 (see FIG. 1) is, for example, 350 mm to 600 mm. The length L11 in the Z-axis direction of the module 1 (see FIG. 1) is, for example, 150 mm to 250 mm. The length L12 in the X-axis direction of the module 1 (see FIG. 1) is, for example, 80 mm to 110 mm.

[0026] A pair of voltage terminals 11 and a connector 12 are provided at both ends in the Y-axis direction of the module 1. A flexible printed circuit board 13 described later is connected to the connector 12. Bus bars (not shown) are welded to both ends in the Y-axis direction of the module 1.

[0027] The metal case 10 has a metal case body 101 and a metal case lid 102. The metal case 10 is formed of an aluminum alloy. The metal case 10 is formed, for example, by joining aluminum die-castings to both ends of an extruded material of an aluminum alloy by laser welding or the like.

[0028] As shown in FIG. 2, inside the module 1, a plurality of batteries 2 are accommodated in an arranged state. In the present embodiment, 24 batteries 2 are arranged along the Z-axis direction. Adjacent batteries 2 are adhered to each other. Details of the battery 2 will be described later with reference to FIGS. 3 and 4.

[0029] A flexible printed circuit (FPC) 13 is disposed on the battery 2. The flexible printed circuit board 13 is formed in a strip shape with the Y-axis direction as the longitudinal direction, and thermistors 14 are provided at both ends of the flexible printed circuit board 13, respectively. In the module 1, the thermistor 14 is not adhered to the battery 2 and is pressed toward the battery 2 side by the metal case lid 102.

[0030] One or more cushioning materials (not shown) are accommodated inside the module 1. For example, the cushioning material is a thin plate-like member that can be elastically deformed and is disposed between adjacent batteries 2 with the arrangement direction of the batteries 2 as the thickness direction. In the present embodiment, as an example, cushioning materials are disposed at both longitudinal ends and the central portion in the longitudinal direction of the module 1, respectively.

[0031] (1.2) Battery As shown in FIG. 3, the battery 2 includes an electrode body 21, a laminate exterior body 22, a positive electrode tab 23, a negative electrode tab 24, and a non-aqueous electrolyte (not shown). The battery 2 is a rectangular parallelepiped.

[0032] The laminated exterior body 22 houses the electrode body 21 and the non-aqueous electrolyte. The positive electrode tab 23 protrudes from the laminated exterior body 22 in the positive Y-axis direction. The negative electrode tab 24 protrudes from the laminated exterior body 22 in the negative Y-axis direction.

[0033] The length L1 (see Figure 3) of the battery 2 in the Y-axis direction is, for example, 530 mm to 600 mm. The length L2 (see Figure 3) of the battery 2 in the X-axis direction is, for example, 80 mm to 110 mm. The length L3 (see Figure 4) of the battery 2 in the Z-axis direction is, for example, 7.0 mm to 9.0 mm.

[0034] (1.2.1) Electrode body The structure of the electrode body 21 is a laminated type. As shown in Figure 4, the electrode body 21 includes a plurality of positive electrode sheets 211, a plurality of negative electrode sheets 212, and a plurality of separator sheets 213. In the electrode body 21, the positive electrode sheets 211 and the negative electrode sheets 212 are alternately laminated along the Z-axis direction with the separator sheets 213 interposed therebetween.

[0035] The number of each of the positive electrode sheet 211, the negative electrode sheet 212, and the separator sheet 213 is not particularly limited and is appropriately selected according to the use of the battery 2 and the like.

[0036] (1.2.1.1) Positive electrode sheet The positive electrode sheet 211 has a positive electrode current collector 2111 (for example, aluminum foil or the like) and a positive electrode active material layer 2112 supported on both surfaces of the positive electrode current collector 2111. The positive electrode active material layer 2112 contains a positive electrode active material. The positive electrode active material releases lithium ions into the non-aqueous electrolyte or occludes lithium ions from the non-aqueous electrolyte. The positive electrode active material may be a known positive electrode active material (for example, LiNiO2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2, etc.). The positive electrode active material layer 2112 may further contain a known conductive material (for example, carbon black or the like), lithium phosphate, and a known binder (for example, polyvinylidene fluoride or the like).

[0037] (1.2.1.2) Negative electrode sheet The negative electrode sheet 212 has a negative electrode current collector 2121 (for example, a copper foil or the like) and negative electrode active material layers 2122 supported on both sides of the negative electrode current collector 2121. The negative electrode active material layers 2122 contain a negative electrode active material. The negative electrode active material occludes lithium ions, which are charge carriers, from the non-aqueous electrolyte during charge and discharges, and releases them into the non-aqueous electrolyte. The negative electrode active material may be a known negative electrode active material (artificial graphite, a lithium alloy (for example, LiXM, where M is C, Si, Sn, Sb, Al, Mg, Ti, Bi, Ge, Pb, or P, etc., and X is a natural number), etc.). The negative electrode active material layers 2122 may further contain a known binder (for example, a styrene-butadiene copolymer, etc.).

[0038] (1.2.1.3) Separator Sheet The separator sheet 213 electrically insulates the positive electrode sheet 211 and the negative electrode sheet 212, and provides a migration path for lithium ions between the positive electrode active material layer 2112 and the negative electrode active material layer 2122. Examples of the separator sheet 213 include a porous film. Examples of the material of the porous film include polyethylene, polypropylene, etc. The separator sheet 213 may have a single-layer structure or a multilayer structure.

[0039] (1.2.2) Laminate Exterior Body The laminate exterior body 22 covers the electrode body 21 and seals the electrode body 21 and the non-aqueous electrolyte together with the positive electrode tab 23 and the negative electrode tab 24. In the present embodiment, the laminate exterior body 22 has a single cup structure (see FIG. 4). The "laminate exterior body with a single cup structure" means a single laminate exterior body that has a folding line, a single cup portion (recess) capable of accommodating the entire electrode body, and a flat portion, and by being bent along the folding line, the flat portion covers the recess. The laminate exterior body 22 is flat.

[0040] As shown in FIG. 4, the laminated exterior body 22 includes a laminated sheet 221, two rigid layers 222, and a plurality of tab films 223. In the present embodiment, the rigid layers 222 are formed on the surfaces of both main surfaces of the laminated exterior body 22 on the side of the electrode body 21. Each of the plurality of tab films 223 is welded to the positive tab 23 or the negative tab 24 and the laminated sheet 221.

[0041] (1.2.2.1) Laminated Sheet The laminated sheet 221 includes a metal layer, an inner resin layer, and an outer resin layer. The inner resin layer is laminated on the surface of the metal layer on the side of the electrode body 21. The outer resin layer is laminated on the surface of the metal layer opposite to the side of the electrode body 21. The metal layer blocks the entry and exit of gas (e.g., moisture, air, etc.) between the outside and the inside of the battery 2. The material of the metal layer is metal (e.g., aluminum, etc.). The inner resin layer electrically insulates the electrode body 21, the positive tab 23, and the negative tab 24 from the metal layer. The inner resin layer may contain a thermoplastic resin. The outer resin layer improves the durability of the laminated sheet 221. The outer resin layer may contain a thermoplastic resin. Examples of the thermoplastic resin for each of the inner resin layer and the outer resin layer include olefin-based resins (e.g., polypropylene, polyethylene, etc.), polyvinyl chloride, polyvinylidene chloride, etc.

[0042] (1.2.2.2) Rigid Layer The rigid layer 222 has electrical insulation. In other words, the electrical resistance of the rigid layer 222 is 10 10 Ω·m or more. The Mohs hardness of the rigid layer 222 is 3.0 or more. In other words, the elongation rate of the rigid layer 222 is less than 10%.

[0043] As shown in FIG. 3, when viewed from the thickness direction (Z-axis direction) of the electrode body 21, each of the two rigid layers 222 is formed so as to cover the entire electrode body 21. In other words, when the laminated exterior body 22 is viewed from the thickness direction (Z-axis direction) of the electrode body 21, the two rigid layers 222 are included in the portion overlapping the electrode body 21.

[0044] The thickness of the hard layer 222 is not particularly limited and is appropriately selected according to the material of the hard layer 222. The thickness of the hard layer 222 may be, for example, 1.0 mm.

[0045] In this embodiment, the hard layer 222 contains ceramics and may be made of ceramics. Examples of the ceramics include oxide-based ceramics and nitride-based ceramics. Examples of the oxide-based ceramics include silica, titania, zirconia, magnesia, ceria, yttria, zinc oxide, iron oxide, cordierite, mullite, alumina, etc. Examples of the nitride-based ceramics include silicon nitride, titanium nitride, boron nitride, etc. These ceramics may be used alone or in combination of two or more.

[0046] (1.2.2.3) Tab film The tab film 223 has a function of electrically insulating the laminate sheet 221 from the positive electrode tab 23 and the negative electrode tab 24, and a function of joining the laminate sheet 221 to the positive electrode tab 23 and the negative electrode tab 24. The tab film 223 contains a thermoplastic resin. Examples of the thermoplastic resin of the tab film 223 are the same as those exemplified as the thermoplastic resin of each of the inner resin layer and the outer resin layer.

[0047] (1.2.4) Positive electrode tab The positive electrode tab 23 is electrically connected to a plurality of positive electrode current collectors 2111. The positive electrode tab 23 has a metal sheet 231 and a positive electrode lead portion R2111 of the positive electrode current collector 2111. The metal sheet 231 and the positive electrode lead portion R2111 are electrically connected. Examples of the material of the metal sheet 231 include metals (for example, aluminum, stainless steel (SUS), etc.). The length L4 of the positive electrode tab 23 in the X-axis direction is, for example, 40 mm to 50 mm.

[0048] (1.2.5) Negative electrode tab The negative electrode tab 24 is electrically connected to a plurality of negative electrode current collectors 2121. The negative electrode tab 24 has a metal sheet 241 and a negative electrode lead portion R2121 of the negative electrode current collector 2121. The metal sheet 241 and the negative electrode lead portion R2121 are electrically connected. Examples of the material of the metal sheet 241 include metals (such as stainless steel (SUS), etc.). The length L5 of the negative electrode tab 24 in the X-axis direction is, for example, 40 mm to 50 mm.

[0049] (1.2.6) Non-aqueous electrolyte The battery 2 includes a non-aqueous electrolyte. The non-aqueous electrolyte is housed together with the electrode body 21 in the laminate exterior body 22. The non-aqueous electrolyte may be one in which a supporting salt (such as LiPF6, etc.) as an electrolyte is dissolved or dispersed in a non-aqueous solvent (such as ethyl carbonate, etc.). The non-aqueous electrolyte may contain various additives (such as lithium bis(oxalato)borate, etc.).

[0050] (1.3) Function and effect As described with reference to FIGS. 1 to 4, the battery 2 includes an electrode body 21 and a laminate exterior body 22. The laminate exterior body 22 has a hard layer 222 at a portion overlapping the electrode body 21 when viewed from the thickness direction of the electrode body. Thereby, foreign matters (such as cutting chips of the metal case 10, metal powder during ultrasonic bonding of the positive electrode current collector 2111 and the positive electrode tab 23, metal powder during ultrasonic bonding of the negative electrode current collector 2121 and the negative electrode tab 24, etc.) are difficult to penetrate the hard layer 222. Thereby, foreign matters are less likely to enter the inside of the laminate exterior body 22 than in a configuration where the laminate exterior body 22 does not include the hard layer 222. As a result, the occurrence of a short circuit in the electrode body 21 of the battery 2 is suppressed. The laminate exterior body 22 may have the hard layer 222 on at least one of the surfaces on the electrode body 21 side of both main surfaces of the laminate exterior body 22 and the surfaces on the opposite side of the surfaces, and it is preferable that the laminate exterior body 22 has the hard layer 222 on the surfaces on the electrode body 21 side of both main surfaces.

[0051] As described with reference to FIGS. 1 to 4, in the battery 2, the hard layer 222 has electrical insulation properties. As a result, the occurrence of a short circuit in the electrode body of the battery 2 is further suppressed.

[0052] As described with reference to FIGS. 1 to 4, in the battery 2, the hard layer 222 contains ceramics. That is, the Mohs hardness of the hard layer 222 is higher. As a result, the occurrence of a short circuit in the electrode body of the battery 2 is further suppressed.

[0053] As described with reference to FIGS. 1 to 4, in the battery 2, the laminate exterior body 22 is flat, and it is preferable that the laminate exterior body 22 has the hard layer 222 on the surfaces on the electrode body 21 side of both main surfaces of the laminate exterior body 22. As a result, foreign matter is less likely to enter the interior of the laminate exterior body 22 than in a configuration where the hard layer 222 is not provided on the surfaces on the electrode body 21 side of both main surfaces of the laminate exterior body 22. As a result, the occurrence of a short circuit in the electrode body 21 of the battery 2 is further suppressed.

[0054] As described with reference to FIGS. 1 to 4, the module 1 includes a plurality of batteries 2 and a metal case 10. As a result, the occurrence of a short circuit in the electrode body 21 of the module 1 is suppressed.

[0055] (2) Modification In the present embodiment, the hard layer 222 has electrical insulation properties, but the present disclosure is not limited thereto. As long as the Mohs hardness of the hard layer 222 is 3.0 or more, it does not necessarily have to have electrical insulation properties.

[0056] In the present embodiment, the hard layer 222 contains ceramics, but the present disclosure is not limited thereto. As long as the Mohs hardness of the hard layer 222 is 3.0 or more, it does not necessarily have to contain ceramics. The hard layer 222 may contain glass. Examples of the glass include borosilicate glass, fused quartz, 96% fused quartz, soda-lime glass, aluminoborosilicate glass, aluminosilicate glass, lead glass, neoseram, and the like. The hard layer 222 preferably contains at least one of ceramics and glass. Thereby, the Mohs hardness of the hard layer 222 is relatively high. As a result, the occurrence of a short circuit in the electrode body 21 of the battery 2 is more suppressed.

[0057] In the present embodiment, the laminated exterior body 22 is flat, but the present disclosure is not limited to this, and it may not be flat. In the present embodiment, the laminated exterior body 22 has the hard layers 222 on both main surfaces on the electrode body 21 side, but the present disclosure is not limited to this. The laminated exterior body 22 may have the hard layer 222 on one main surface on the electrode body 21 side.

[0058] In the present embodiment, the positive electrode tab 23 has the metal sheet 231 and the positive electrode lead portion R2111 of the positive electrode current collector 2111, but the present disclosure is not limited to this. The positive electrode tab 23 may be composed of the positive electrode lead portion R2111 of the positive electrode current collector 2111.

[0059] In the present embodiment, the laminated exterior body 22 has a single cup structure (see FIG. 4), but the present disclosure is not limited to this. In the present disclosure, the laminated exterior body 22 may have a double cup structure. The "double cup structure" has a folding line, one first cup portion (recess) capable of accommodating a part of the electrode body, and one second cup portion (recess) capable of accommodating a part of the electrode body, and by being bent along the folding line, it indicates a single laminated exterior body capable of accommodating the entire electrode body in a space formed by the overlapping of the first cup portion and the second cup.

[0060] In the present embodiment, the positive electrode tab 23 protrudes from the laminated exterior body 22 in the positive Y-axis direction, and the negative electrode tab 24 protrudes from the laminated exterior body 22 in the negative Y-axis direction, but the present disclosure is not limited to this. In the present disclosure, the positive electrode tab 23 and the negative electrode tab 24 may protrude from the laminated exterior body 22 in the positive Y-axis direction or the negative Y-axis direction.

[0061] In this embodiment, the number of batteries 2 accommodated in module 1 is 24, but the present disclosure is not limited thereto. The number of batteries 2 accommodated in module 1 may be less than 23 or may be 25 or more.

[0062] In this embodiment, the use of battery 2 is a power source for a vehicle, but the present disclosure is not limited thereto. In the present disclosure, the use of battery 2 may be, for example, a power source for an information processing device (e.g., a personal computer, a smartphone, etc.), a power source for power storage, or the like.

Explanation of Reference Numerals

[0063] 1: Module, 2: Battery, 10: Metal case, 101: Metal case body, 102: Metal case lid, 11: Voltage terminal, 12: Connector, 13: Flexible printed circuit board, 14: Thermistor, 21: Electrode body, 211: Positive electrode sheet, 2111: Positive electrode current collector, 2112: Positive electrode active material layer, 212: Negative electrode sheet, 2121: Negative electrode current collector, 2122: Negative electrode active material layer, 213: Separator sheet, 221: Laminate sheet, 222: Rigid layer, 223: Tab film, 231: Metal sheet, 241: Metal sheet, 22: Positive electrode tab, 22: Laminate exterior body, 23: Positive electrode tab, 24: Negative electrode tab, 25: Electrically insulating layer, R2111: Positive electrode lead portion, R2121: Negative electrode lead portion

Claims

1. An electrode body in which a positive electrode body and a negative electrode body are alternately laminated with a separator interposed therebetween; A laminated exterior body that houses the electrode body; A battery comprising: The laminated exterior body includes a hard layer in a portion overlapping the electrode body when viewed from the thickness direction of the electrode body.

2. The battery according to claim 1, wherein the hard layer has electrical insulation properties.

3. The battery according to claim 2, wherein the hard layer contains at least one of ceramics and glass.

4. The laminated exterior body is flat, The battery according to claim 3, wherein the surface on the electrode body side includes the surfaces on the electrode body side of both main surfaces of the laminated exterior body.

5. A plurality of batteries according to any one of claims 1 to 4; A metal case that houses the plurality of batteries; A module comprising:

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