Battery and module

Abstract

A battery comprises a layered electrode body, a laminate outer body, a positive electrode strip, and a negative electrode strip. Within the electrode body, a positive electrode foil and a negative electrode foil are alternately layered over a separator foil in a single layering direction. The positive electrode strip projects from the laminate outer body in a first direction orthogonal to the layering direction in one direction. The negative electrode strip projects from the laminate outer body in a first direction in one direction or the other. The electrode body has an overlap zone where, at both edges, multiple separator foils overlap in a second direction orthogonal to both the layering direction and the first direction. At least one of the two overlap zones has multiple weld sections where the multiple separator foils are welded together.The multiple weld sections are discretely formed along the first direction.

Description

BACKGROUND Technical Area

[0001] The present disclosure relates to a battery and a module. Related state of the art

[0002] Japanese Patent Application (JP-A) No. 2021-22421 discloses a secondary battery with a non-aqueous electrolyte (hereinafter also referred to as the "battery"). The battery is provided with a negative electrode, a positive electrode, and a separator. The negative electrode has a negative electrode active material layer on at least a portion of a current collector and has folded sections that are alternately folded back. The positive electrode has a positive electrode active material layer on at least a portion of a current collector and is inserted into the folded sections. The separator is inserted between the negative and positive electrodes. The separator is arranged in a film-like form on both surfaces of the positive electrode. An adhesive section is provided to which at least a portion of an outer circumferential section of the separator is adhered. JP-A No.2021-22421 discloses in particular a battery in which, as in . Fig. Figure 6 shows that adhesive sections 900a, 900b, 900c, 900d are formed on all sides of an outer circumferential section of a separator 900. Fig. Reference numeral 6 designates 910 as a power generating element equipped with a positive electrode, a negative electrode, and a separator. Reference numeral 911 designates a negative electrode terminal extending from power generating element 910. Reference numeral 912 designates a positive electrode terminal extending from power generating element 920.

[0003] In a case where the battery is repeatedly charged and discharged, gas can be generated due to the progression of a decomposition reaction of the non-aqueous electrolyte. In the separator 900 disclosed in JP-A No. 2021-22421, adhesive sections 900a, 900b, 900c, 900d are formed on all sides. In other words, the separator 900 surrounds the entire positive electrode via the adhesive sections 900a, 900b, 900c, 900d. Therefore, gas is likely to accumulate between the separator and the positive electrode. In a case where gas accumulates between the separator and the positive electrode, the battery reaction becomes less likely at the point where the gas accumulates, causing lithium metal to tend to deposit on the surface of the positive electrode. As the lithium metal grows, a short circuit can occur between the positive electrode and the negative electrode. SUMMARY

[0004] The present disclosure provides a battery and a module that can suppress the occurrence of short circuits.

[0005] A first embodiment of the present disclosure is a battery comprising: a layered electrode body formed from a positive electrode foil and a negative electrode foil, which are layered alternately in a layering direction with a separator foil arranged between them; a laminate outer body receiving the electrode body; a first strip projecting from the laminate outer body in a first direction orthogonal to the layering direction in a side direction, the first strip being electrically connected to several positive electrode foils;and a second strip projecting from the laminate outer body in the first direction towards one side or the other, the second strip being electrically connected to several negative electrode foils, the electrode body having an overlap area at respective edge regions in a second direction orthogonal to the layering direction and to the first direction, where only several separator foils overlap each other, at least one of the two overlap areas having a plurality of weld sections where the several separator foils are welded together, and the multiple weld sections being discrete along the first direction.

[0006] The term "layered electrode body" refers here to a battery in which a positive electrode foil, a negative electrode foil, and a separator foil are all in the form of a single wafer, and the positive and negative electrode foils are stacked alternately, with a separator foil inserted between them. Furthermore, the term "laminate outer body" refers to a housing made of a laminated foil. Additionally, "laminate foil" refers to a foil with at least one metal layer, a first resin layer on one main surface of the metal layer, and a second resin layer on the other main surface of the metal layer.

[0007] In the first embodiment, the multiple weld sections are discretely formed along the first direction. Therefore, the gas generated between the separator foil and at least one of the positive electrode foils or the negative electrode foil (hereinafter also referred to as "positive / negative electrode foils") moves easily to the outside of the electrode body between adjacent weld sections of the separator foil's overlap area. This is more pronounced when the direction of the weld section formation is upward in the second direction. In other words, gas is less likely to accumulate between the separator foil and the positive or negative electrode foils than in the conventional configuration. Consequently, lithium metal is less likely to be deposited on the surface of the positive and negative electrode foils.Furthermore, the multiple separator films are integrated through the multiple weld sections, and the separator film is securely inserted between the positive electrode film and the negative electrode film. As a result, the occurrence of short circuits can be suppressed in the battery of the first embodiment.

[0008] In a second embodiment of the present disclosure, the lengths of the several weld sections in the first direction can be identical in the first embodiment.

[0009] Consequently, gas generated between the separator foil and the positive or negative electrode foils is more likely to escape from the electrode body than in a configuration where the lengths of the multiple welding sections are not equal in the first direction. As a result, the occurrence of a short circuit can be further suppressed in the battery of the second configuration.

[0010] In a third embodiment of the present disclosure, gaps between adjacent weld sections in the first direction can be identical in the above first or second embodiment among the plurality of weld sections.

[0011] Consequently, gas forming between the separator foil and the positive or negative electrode foils is more likely to escape from the electrode body than in a configuration where the gaps between adjacent weld sections are not equal in the first direction. As a result, the occurrence of short circuits can be further suppressed in the battery of the third embodiment.

[0012] In a fourth embodiment of the present disclosure, in one of the above first to third embodiments, both of the two overlapping areas can have a plurality of weld sections that are discretely formed along the first direction.

[0013] Consequently, gas generated between the separator foil and the positive / negative electrode foils tends to escape from the electrode body more easily than in a configuration where one of the two overlapping areas has a weld section that is continuous along the first direction. As a result, the occurrence of short circuits can be further suppressed in the battery of the fourth embodiment.

[0014] A fifth embodiment of the present disclosure is a module comprising: the battery of one of the above first to fourth embodiments; a housing accommodating a plurality of the batteries, wherein one direction of a side on which the weld sections are formed points upwards in the second direction.

[0015] The term "upwards" here refers to the direction opposite to gravity.

[0016] In general, the specific gravity of a gas generated by a decomposition reaction of a non-aqueous electrolyte or the like is less than the specific gravity of a non-aqueous electrolyte. In other words, the gas in a non-aqueous electrolyte tends to move upwards. In the fifth embodiment, the direction in the second direction on the side where the weld section is formed is upwards. In other words, the battery is arranged such that the area on the side where the weld section is discretely formed along the first direction points upwards between the two overlapping areas of the multiple separator films. Consequently, the gas generated between the separator film and the positive electrode films or negative electrode films tends to move outwards above the electrode body.As a result, the occurrence of a short circuit can be further suppressed in the module of the fifth configuration.

[0017] According to the above embodiments, the battery and the module of the present disclosure can suppress the occurrence of a short circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Exemplary implementations are described in detail with reference to the following figures. They show: Fig. 1 a perspective view of a module in an embodiment of the present disclosure; Fig. 2 a top view of the module according to the embodiment of the present disclosure in a state in which the housing cover is removed; Fig. a front view of a battery according to an embodiment of the present disclosure; Fig. 4 a front view of an electrode body according to an embodiment of the present disclosure; Fig. 5 a cross-sectional view along line VV of Fig. 4; and Fig. A front view of a separator from a conventional battery. DETAILED DESCRIPTION

[0019] The following are descriptions of embodiments of the present disclosure. These descriptions and examples illustrate embodiments and do not limit the scope of the embodiments. In the present disclosure, a combination of two or more preferred embodiments is a preferred embodiment. In the present disclosure, a numerical range expressed by "to" means a range in which the numerical values ​​described before and after "to" are included as a lower limit and an upper limit, respectively. In the numerical ranges specified stepwise in the present disclosure, the upper or lower limit specified in one numerical range may be replaced by the upper or lower limit of another numerical range described stepwise.In the numerical ranges specified in the present disclosure, the upper or lower limit of the numerical range can be replaced by a value given in the examples.

[0020] Exemplary embodiments of a battery and a module of the present disclosure are described below with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and their description will not be repeated. (1) Module

[0021] As in the Fig. 1 and Fig. Figure 2 shows a module 1 according to an embodiment of the present disclosure, provided with several batteries 2 and a housing 10. The housing 10 accommodates the several batteries 2. The module 1 has the shape of a rectangular parallelepiped.

[0022] In the present embodiment, the thickness direction of module 1 is defined as the X-axis direction, the longitudinal direction of the main surface of module 1 as the Y-axis direction, and the transverse direction of module 1 as the Z-axis direction. The X-axis, Y-axis, and Z-axis are each orthogonal to one another. The direction of the X-axis is an example of a second direction. The positive direction of the X-axis is an example of a top direction. The direction of the Y-axis is an example of a first direction. The direction of the Z-axis is an example of a stacking direction. It should be noted that these orientations do not restrict the orientation of the battery and the module of this disclosure during use.

[0023] The length L10 of module 1 in the Y-axis direction is, for example, 350 mm to 600 mm. The length L11 of module 1 in the Z-axis direction is, for example, 150 mm to 250 mm. The length L12 of module 1 in the X-axis direction is, for example, 80 mm to 110 mm.

[0024] At each end of module 1, in the direction of the Y-axis, a pair of voltage terminals 11 and a connector 12 are provided. A flexible circuit board 13, which will be described later, is connected to the connector 12. A busbar (not shown) is welded to both ends of module 1 in the direction of the Y-axis.

[0025] The housing 10 has a housing body 101 and a housing cover 102. The housing 10 is made of an aluminum alloy. The housing 10 is formed, for example, by joining an aluminum die-cast part with both end sections of an extruded aluminum alloy material by laser welding or the like.

[0026] As in Fig. As shown in Figure 2, several batteries 2 are housed in module 1 in an arrangement. In the present embodiment, twenty-four batteries 2 are arranged along the Z-axis. Adjacent batteries 2 are glued together. Details of the batteries 2 will be described later with reference to Figure 2. Fig. 3 to 5 described.

[0027] A flexible printed circuit board (FPC) 13 is arranged on the battery 2. The flexible printed circuit board 13 is ribbon-shaped with the X-axis direction as its longitudinal direction, and thermistors 14 are provided at both end sections of the flexible printed circuit board 13. In module 1, the thermistor 14 is not glued to the battery 2, but is pressed towards the battery 2 by the housing cover 102.

[0028] Inside module 1 are one or more cushioning materials (not shown). The cushioning material is, for example, a thin, plate-shaped element that is elastically deformable and arranged between adjacent batteries 2, the arrangement direction of the batteries 2 being the thickness direction. In the present embodiment, the cushioning materials are, for example, arranged longitudinally at both ends of module 1 or longitudinally in the middle part. (2) Battery

[0029] As in Fig. As shown in Figure 3, the battery 2 is provided with an electrode body 21, a laminate outer body 22, a positive electrode strip 23, a negative electrode strip 24, and a non-aqueous electrolyte (not shown). The battery 2 has a rectangular, parallelepiped shape.

[0030] The laminate outer body 22 houses the electrode body 21 and the non-aqueous electrolyte. The positive electrode strip 23 projects out of the laminate outer body 22 in the positive direction of the Y-axis. The negative electrode strip 24 projects out of the laminate outer body 22 in the negative direction of the Y-axis.

[0031] The length L1 of battery 2 in the direction of the Y-axis (see Fig. 3) is, for example, 530 mm to 600 mm. The length L2 of battery 2 in the direction of the X-axis (see Fig. 3) is, for example, 80 mm to 110 mm. The length L3 of battery 2 in the direction of the Z-axis (see Fig. 5) is, for example, 7.0 mm to 9.0 mm. (2.1) Electrode body

[0032] The electrode body 21 has a layered structure. As in Fig. As shown in Figure 5, the electrode body 21 comprises several positive electrode foils 211, several negative electrode foils 212, and several separator foils 213. In the electrode body 21, a positive electrode foil 211 and a negative electrode foil 212 are stacked alternately in the direction of the Z-axis, with a separator foil 213 arranged between them.

[0033] As in Fig. As shown in Figure 4, the electrode body 21 has an overlap region R213 on both edge regions in the direction of the X-axis. In the overlap region R213, the electrodes overlap, as shown in Figure 4. Fig. As shown in Figure 5, only the multiple separator films 213 are mutually connected. In the present embodiment, the two overlapping areas R213 have multiple weld sections W213. Several separator films 213 are welded to the weld section W213. The multiple weld sections W213 are discretely arranged in the direction of the Y-axis. In the present embodiment, the length L4 of each of the multiple weld sections W213 in the direction of the Y-axis (see Figure 5) is... Fig. 4) same. Among the several weld sections W213, the gap L5 is (see Fig. 4) between adjacent weld sections W213 in the direction of the Y-axis the same.

[0034] The respective number of positive electrode foil 211, negative electrode foil 212 and separator foil 213 is not particularly limited and is selected according to the use of battery 2. (2.1.1) Positive electrode foil

[0035] The positive electrode foil 211 has a positive electrode current collector 2111 (e.g., aluminum foil or similar) and a positive electrode active material layer 2112, which rests 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 encapsulates lithium ions from it. The positive electrode active material can be a known positive electrode active material (e.g., LiNiO2 or LiNi). 1 / 3 Co 1 / 3 Mn 1 / 3 O2). The positive electrode active material layer 2112 may further contain a known conductive material (e.g., carbon black), trilithium phosphate, and a known binder (e.g., polyvinylidene fluoride). (2.1.2) Negative electrode foil

[0036] The negative electrode foil 212 has a negative electrode current collector 2121 (e.g., a copper foil or the like) and a negative electrode active material layer 2122 applied to both surfaces of the negative electrode current collector 2121. The negative electrode active material layer 2122 contains a negative electrode active material. When the negative electrode active material charges and discharges, lithium ions, which are charge carriers, are trapped from the non-aqueous electrolyte and released into the non-aqueous electrolyte. The negative electrode active material can be any known negative electrode active material (artificial graphite or lithium alloy (e.g., LiXM, where MC, Si, Sn, Sb, Al, Mg, Ti, Bi, Ge, Pb, or P and X are natural numbers)). The negative electrode active material layer 2122 may also contain a known binder (e.g. a styrene-butadiene copolymer). (2.1.3) Separator film

[0037] The separator film 213 electrically insulates the positive electrode film 211 and the negative electrode active material layer 212 and establishes a lithium-ion transfer path between the positive electrode active material layer 2112 and the negative electrode active material layer 2122. Examples of separator films 213 are porous films. Examples of materials for the porous film are polyethylene and polypropylene. The separator film 213 can have a single-layer or a multi-layer structure. (2.2) Laminate outer body

[0038] The laminate outer body 22 covers the electrode body 21 and seals the electrode body 21 and the non-aqueous electrolyte together with the positive electrode strip 23 and the negative electrode strip 24. In the present embodiment, the laminate outer body 22 has a single-cup structure (see Fig. 5) Here, the term “laminate outer body with single-cup structure” refers to a single laminate outer body with a bending line, a cup section (recessed section) that can accommodate the entire electrode body, and a flat section, the flat section covering the recessed section as a result of bending along the bending line. The laminate outer body 22 comprises a laminate film. (2.2.1) Laminate film

[0039] The laminate film consists of a metal layer, an inner resin layer, and an outer resin layer. The inner resin layer is applied to the surface of the metal layer on the side facing the electrode body 21. The outer resin layer is applied to the surface of the metal layer on the side facing away from the electrode body 21. The metal layer prevents gas (e.g., moisture or air) from entering and exiting the battery 2 from the outside and inside the battery 2. The material of the metal layer is a metal (e.g., aluminum). The inner resin layer electrically insulates the electrode body 21, the positive electrode strip 23, and the negative electrode strip 24 from the metal layer. The inner resin layer may contain a thermoplastic resin. The outer resin layer improves the durability of the laminate film. The outer resin layer may also contain a thermoplastic resin.Examples of thermoplastic resins used in both the inner and outer resin layers are olefinic resins (e.g., polypropylene, polyethylene, and the like), polyvinyl chloride, and polyvinylidene chloride. (2.3) Positive electrode strip

[0040] The positive electrode strip 23 is electrically connected to the multiple positive electrode current collectors 2111. Examples of materials for the positive electrode strip 23 are metals (e.g., stainless steel (SUS)). The length L6 of the positive electrode strip 23 in the direction of the Y-axis (see Fig. 3) is, for example, 40 mm to 50 mm. (2.4) Negative electrode strips

[0041] The negative electrode strip 24 is electrically connected to the multiple negative electrode current collectors 2121. Examples of the material for the negative electrode strip 24 include a metal (e.g., stainless steel (SUS)). The length L7 of the negative electrode strip 24 in the direction of the Y-axis (see Fig. 3) is, for example, 40 mm to 50 mm. (2.5) Non-aqueous electrolyte

[0042] The battery 2 is provided with a non-aqueous electrolyte. The non-aqueous electrolyte is housed in the laminate outer body 22 together with the electrode body 21. It is sufficient that the non-aqueous electrolyte is a solution in which a carrier salt as electrolyte (e.g., LiPF6) is dissolved or dispersed in a non-aqueous solvent (e.g., ethyl carbonate). The non-aqueous electrolyte may contain various additives (e.g., lithium bis-(oxalato)borate). (3) Mechanism

[0043] As with reference to the Fig. As described in Figures 1 to 5, the battery 2 is provided with the electrode body 21, the laminate outer body 22, the positive electrode strip 23, and the negative electrode strip 24. The electrode body 21 has an overlap area R213. The overlap area R213 has several weld sections W213. The several weld sections W213 are discretely arranged in the direction of the Y-axis. As a result, gas generated between the separator film 213 and at least one of the positive electrode films 211 or the negative electrode film 212 (hereinafter referred to as "positive / negative electrode films 211, 212") can more easily pass through the gaps G213 (see Figure 1). Fig. 4) between the adjacent weld sections of the overlap areas R213 of the separator foils 213 to the outside of the electrode body 21. In other words, gas is less likely to accumulate between the separator foil 213 and the positive electrode foils 211, 212 than in a conventional configuration. Consequently, lithium metal is less likely to be deposited on the surface of the positive electrode foils 211, 212. Furthermore, the multiple separator foils 213 are integrated by the multiple weld sections W213, and the separator foil 213 is securely inserted between the positive electrode foil 211 and the negative electrode foil 212. As a result, the occurrence of short circuits in the battery 2 can be suppressed.

[0044] As with reference to the Fig. As described in sections 1 to 5, in battery 2 the length L4 of each of the several weld sections W213 in the direction of the Y-axis is the same (see Fig. 4) As a result, the gas generated between the separator foil 213 and the positive electrode foils 211, 212 can easily escape from the electrode body 21 compared to a configuration where the lengths of the multiple welding sections W213 differ in the Y-axis direction. Consequently, the occurrence of short circuits in the battery 2 can be further suppressed.

[0045] As with reference to the Fig. As described in 1 to 5, the gap L5 in battery 2 (see Fig. 4) The distances between adjacent welding sections W213 in the Y-axis direction are the same among the multiple welding sections W213. As a result, the gas generated between the separator foil 213 and the positive electrode foils 211, 212 moves slightly out of the electrode body 21 compared to a configuration where the distances of the adjacent welding sections W213 differ in the Y-axis direction. Consequently, the occurrence of short circuits in the battery 2 can be further suppressed.

[0046] As with reference to the Fig. As described in Figures 1 to 5, in battery 2 both overlapping areas R213 have several weld sections W213 that are discretely formed along the Y-axis direction. This means that gas generated between the separator foil 213 and the positive electrode foils 211, 212 can easily escape from the electrode body 21 compared to a configuration in which one of the two overlapping areas R213 has a weld section W213 that is continuous along the Y-axis direction. Consequently, the occurrence of short circuits in battery 2 can be further suppressed.

[0047] As with reference to the Fig. As described in sections 1 to 5, module 1 is equipped with several batteries 2 and a housing 10. The direction of the Y-axis of the side on which the weld section W213 is formed points upwards.

[0048] In module 1, battery 2 is arranged such that one of the two overlapping areas R213 of the multiple separator foils 213 faces upwards. The gas generated in battery 2 tends to rise. Therefore, the gas generated between separator foil 213 and the positive / negative electrode foils 211, 212 moves slightly outwards over the electrode body 21. As a result, the occurrence of short circuits in module 1 can be further suppressed. (4) Examples of variants

[0049] In the present embodiment, a case was described in which the length L4 of each of the several weld sections W213 in the direction of the Y-axis (see Fig. 4) is the same. However, the present disclosure is not limited to this. In the present disclosure, the length L4 of each of the multiple weld sections W213 in the direction of the Y-axis need not be the same.

[0050] In the present embodiment, a case was described in which the gap L5 (see Fig. 4) between adjacent weld sections W213 in the direction of the Y-axis under several weld sections W213. However, the present disclosure is not limited to this. In the present disclosure, the gap L5 (see Fig. 4) between adjacent weld sections W213 in the direction of the Y-axis under the multiple weld sections W213 are not the same.

[0051] In the present embodiment, both of the two overlapping areas R213 have several weld sections W213 that are discretely formed along the Y-axis direction, but the present disclosure is not limited to this. In the present disclosure, one of the two overlapping areas R213 can have several weld sections W213 that are discretely formed along the Y-axis direction.

[0052] In the present embodiment, a case was described in which the direction of the Y-axis of the side on which the weld section W213 is formed points upwards. However, the present disclosure is not limited to this. In the present disclosure, the direction of the side on which the weld section W213 is formed in the Y-axis direction need not point upwards.

[0053] In the present embodiment, the laminate outer body 22 has a single-cup structure (see Fig.5), but the present disclosure is not limited thereto. In the present disclosure, the laminate outer body 22 may have a double-cup configuration. Here, the term “double-cup configuration” refers to a single laminate outer body with a bending line, a first cup section (recessed section) that can accommodate part of an electrode body, and a second cup section (recessed section) that can accommodate part of an electrode body, which can house the entire electrode body in a space formed by overlapping the first cup section and the second cup with each other by bending along the bending line.

[0054] In the present embodiment, a case was described in which the positive electrode strip 23 projects out of the laminate outer body 22 in the positive direction of the Y-axis and the negative electrode strip 24 projects out of the laminate outer body 22 in the negative direction of the Y-axis. However, the present disclosure is not limited to this. In the present disclosure, the positive electrode strip 23 and the negative electrode strip 24 can project out of the laminate outer body 22 in either the positive or negative Y-axis direction.

[0055] In the present embodiment, a case has been described in which the battery 2 is used to power a vehicle. However, the present disclosure is not limited to this. In the present disclosure, the application of the battery 2 can, for example, be a power supply for an information processing device (e.g., a personal computer, a smartphone, or the like), a power supply for energy storage, or the like. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2021-22421 [0002, 0003]

Claims

[1] Battery with: a layered electrode body formed of a positive electrode foil and a negative electrode foil alternately stacked in a stacking direction with a separator foil interposed therebetween; a laminate outer body that houses the electrode body; a first strip projecting from the laminate outer body toward one side in a first direction orthogonal to the stacking direction, the first strip being electrically connected to a plurality of the positive electrode foils; and a second strip projecting from the laminate outer body in the first direction toward one side or another side, the second strip being electrically connected to a plurality of the negative electrode foils, wherein the electrode body has an overlap region at respective edge regions in a second direction orthogonal to the stacking direction and the first direction, at which only a plurality of the separator films overlap each other, wherein at least one of the two overlapping areas has a plurality of welding portions to which the plurality of separator films are welded, and wherein the plurality of weld portions are discretely formed along the first direction. [2] The battery according to claim 1, wherein lengths of the plurality of weld portions in the first direction are identical. [3] The battery according to claim 2, wherein gaps between adjacent welding portions among the plurality of welding portions are identical in the first direction. [4] The battery according to claim 1, wherein both of the two overlapping regions have a plurality of the welding portions formed discretely along the first direction. [5] Module with: the battery according to any one of claims 1 to 4; and a housing that houses a large number of batteries, wherein a direction of a side on which the welding portions are formed is upward in the second direction.

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