Battery and module

Abstract

The invention relates to a battery and a module. A battery according to the present disclosure is provided with a laminated electrode body, a laminated exterior body, a positive electrode tab, and a negative electrode tab. The electrode body is formed by alternately laminating a positive electrode sheet and a negative electrode sheet with a separator interposed therebetween in a lamination direction. The positive electrode tab protrudes from the laminated exterior body toward one side in a first direction orthogonal to the lamination direction. The negative electrode tab protrudes from the laminated exterior body toward one side or the other side in the first direction. The electrode body has an overlapping region in which only the plurality of separators overlap each other in both edge regions in a second direction orthogonal to the stacking direction and the first direction. At least one of the two overlapping regions has a plurality of welded parts to which the plurality of separators are welded. The plurality of welded parts are formed so as to be discrete in the first direction.

Description

Technical Field

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

[0002] Japanese Patent Gazette No. 2021-22421 discloses a non-aqueous electrolyte secondary battery (hereinafter, also referred to as a "battery"). The battery comprises 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 the current collector, and has a folded portion that is alternately folded back. The positive electrode has a positive electrode active material layer on at least a portion of the current collector, which is inserted into the folded portion. A separator is sandwiched between the negative electrode and the positive electrode. The separator is arranged in a monolithic form on both sides of the positive electrode. There is a bonding portion to which at least a portion of the outer periphery of the separator is bonded. As Figure 6 As shown, Japanese Patent Application Laid-Open No. 2021-22421 specifically discloses a battery in which adhesive portions 900a, 900b, 900c, and 900d are formed on all sides of the outer peripheral portion of a separator 900. Figure 6 In the figure, reference numeral 910 denotes a power generation element including a positive electrode, a negative electrode, and a separator. Reference numeral 911 denotes a negative electrode terminal extending from the power generation element 910. Reference numeral 912 denotes a positive electrode terminal extending from the power generation element 920.

[0003] If the battery is charged and discharged repeatedly, gas may sometimes be generated due to the progress of the decomposition reaction of the non-aqueous electrolyte. The separator 900 disclosed in Japanese Patent Gazette No. 2021-22421 has adhesive portions 900a, 900b, 900c, and 900d formed on all its sides. In other words, the separator 900 surrounds the entire positive electrode using adhesive portions 900a, 900b, 900c, and 900d. Therefore, gas is easily accumulated between the separator and the positive electrode. If gas accumulates between the separator and the positive electrode, the battery reaction is not easy to progress at the location where the gas accumulates, and lithium metal is easily precipitated on the surface of the positive electrode. If lithium metal grows, a short circuit between the positive and negative electrodes may occur. Summary of the invention

[0004] The present disclosure provides a battery and a module in which occurrence of a short circuit is suppressed.

[0005] The first scheme of the present disclosure is a battery, which comprises: a stacked electrode body, which is formed by stacking positive electrode sheets and negative electrode sheets alternately in a stacking direction with separators therebetween; a laminated outer casing, which accommodates the electrode body; a positive electrode tab, which protrudes from the laminated outer casing on one side of a first direction orthogonal to the stacking direction and is electrically connected to a plurality of positive electrode sheets; and a negative electrode tab, which protrudes from the laminated outer casing on one side or the other side of the first direction and is electrically connected to a plurality of negative electrode sheets, the electrode body having overlapping areas in which only a plurality of separators overlap each other in two edge areas in a second direction orthogonal to the stacking direction and the first direction, at least one of the two overlapping areas having a plurality of welded portions in which a plurality of separators are welded, and the plurality of welded portions are discretely formed along the first direction.

[0006] The “laminated electrode body” refers to a battery in which the positive electrode sheet, the negative electrode sheet, and the separator each have a single sheet (loose leaf) shape, and the positive electrode sheets and the negative electrode sheets are alternately laminated with separators interposed therebetween.

[0007] The “laminated outer package” refers to an outer shell made of a laminate sheet. The “laminated sheet” refers to a sheet having at least 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.

[0008] In the first embodiment, a plurality of welds are discretely formed along the first direction. Therefore, the gas generated between the separator and at least one of the positive electrode sheet and the negative electrode sheet (hereinafter, also referred to as "positive and negative electrode sheets") can easily move to the outside of the electrode body through the adjacent welds in the overlapping area of ​​the separator. This is significant when the direction of the side where the weld is formed in the second direction is upward. In other words, compared with the past, it is not easy for gas to accumulate between the separator and the positive and negative electrode sheets. As a result, it is not easy for lithium metal to precipitate on the surface of the positive and negative electrode sheets. Moreover, the plurality of separators are integrated by a plurality of welds, and the separators are reliably located between the positive electrode sheet and the negative electrode sheet. As a result, in the battery of the first embodiment, the occurrence of a short circuit is suppressed.

[0009] According to a second aspect of the present disclosure, in accordance with the first aspect, the plurality of welded portions may have the same length in the first direction.

[0010] Thus, compared with a configuration in which the lengths of the plurality of welded portions in the first direction are different, the gas generated between the separator and the positive and negative electrode sheets can more easily move to the outside of the electrode assembly. As a result, in the battery of the second aspect, the occurrence of a short circuit is further suppressed.

[0011] According to a third aspect of the present disclosure, in the first or second aspect, intervals between adjacent welded portions in the first direction may be equal among the plurality of welded portions.

[0012] Thus, compared with a configuration in which the intervals between adjacent welded portions in the first direction are different, the gas generated between the separator and the positive and negative electrode sheets can more easily move to the outside of the electrode assembly. As a result, in the battery of the third aspect, the occurrence of a short circuit is further suppressed.

[0013] According to a fourth aspect of the present disclosure, based on the first to third aspects, both of the two overlapping regions may have a plurality of welded portions discretely formed along the first direction.

[0014] Thus, compared with a configuration in which one of the two overlapping regions has a welded portion continuously formed along the first direction, the gas generated between the separator and the positive and negative electrode sheets is more likely to move to the outside of the electrode body. As a result, in the battery of the fourth embodiment, the occurrence of a short circuit is further suppressed.

[0015] A fifth aspect of the present disclosure is a module comprising the plurality of batteries according to any one of the first to fourth aspects and a case for housing the plurality of batteries, wherein the direction of the side where the welded portion is formed in the second direction is upward.

[0016] “Upward” means a direction opposite to the direction of gravity.

[0017] Generally speaking, the specific gravity of the gas generated by the decomposition reaction of the non-aqueous electrolyte is smaller than the specific gravity of the non-aqueous electrolyte. In other words, the gas in the non-aqueous electrolyte tends to move upward. In the fifth embodiment, the direction of the side where the weld is formed in the second direction is upward. In other words, the battery is configured so that the area on the side where the weld is discretely formed along the first direction in the two overlapping areas of the plurality of separators becomes the upper side. Therefore, the gas generated between the separator and the positive and negative electrode sheets tends to move to the outside above the electrode body. As a result, in the module of the fifth embodiment, the occurrence of a short circuit is further suppressed.

[0018] According to the present disclosure, a battery and a module in which occurrence of a short circuit is suppressed are provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Typical embodiments of the present disclosure will be described in detail based on the following drawings.

[0020] Figure 1 is a perspective view of a module according to an embodiment of the present disclosure.

[0021] Figure 2 It is a plan view of a state where a housing cover of a module according to an embodiment of the present disclosure is removed.

[0022] Figure 3 It is a front view of a battery according to an embodiment of the present disclosure.

[0023] Figure 4It is a front view of the electrode body according to the embodiment of the present disclosure.

[0024] Figure 5 yes Figure 4 VV line cross-sectional view.

[0025] Figure 6 This is a front view of a separator of a conventional battery. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present disclosure will be described. These descriptions and examples illustrate the embodiments and do not limit the scope of the embodiments.

[0027] In the present disclosure, a combination of two or more preferred aspects is a more preferred aspect.

[0028] In the present disclosure, a numerical range expressed using "to" means a range including the numerical values ​​described before and after "to" as the lower limit and the upper limit.

[0029] In the numerical range recorded in stages in the present disclosure, the upper limit or lower limit recorded in one numerical range can also be replaced by the upper limit or lower limit of the numerical range recorded in other stages. In the numerical range recorded in the present disclosure, the upper limit or lower limit of the numerical range can also be replaced by the value shown in the embodiment.

[0030] Hereinafter, embodiments of the battery and module disclosed herein will be described with reference to the accompanying drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their description will not be repeated.

[0031] (1) Module

[0032] like Figure 1 and Figure 2 As shown, a module 1 according to an embodiment of the present disclosure includes a plurality of batteries 2 and a housing 10. The housing 10 accommodates the plurality of batteries 2. The module 1 is a rectangular parallelepiped object.

[0033] In this embodiment, the thickness direction of the module 1 is set to the X-axis direction, the long side direction of the main surface of the module 1 is set to the Y-axis direction, and the short side direction of the module 1 is set to the Z-axis direction. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The X-axis direction is an example of the second direction. The positive direction of the X-axis is an example of the upper direction. The Y-axis direction is an example of the first direction. The Z-axis direction is an example of the stacking direction. In addition, these directions do not limit the directions of the battery and module disclosed in the present invention when used.

[0034] The length L10 of the module 1 in the Y-axis direction is, for example, 350 mm to 600 mm. The length L11 of the module 1 in the Z-axis direction is, for example, 150 mm to 250 mm. The length L12 of the module 1 in the X-axis direction is, for example, 80 mm to 110 mm.

[0035] A pair of voltage terminals 11 and a connector 12 are provided at both ends of the module 1 in the Y-axis direction. A flexible printed circuit board 13 described later is connected to the connector 12. Bus bars (not shown) are welded to both ends of the module 1 in the Y-axis direction.

[0036] The housing 10 includes a housing body 101 and a housing cover 102. The housing 10 is formed of an aluminum alloy. The housing 10 is formed by, for example, joining aluminum die castings to both ends of an aluminum alloy extrusion by laser welding or the like.

[0037] like Figure 2 As shown, a plurality of batteries 2 are accommodated in an arranged state inside the module 1. In this embodiment, 24 batteries 2 are arranged along the Z-axis direction. Adjacent batteries 2 are bonded to each other. For details about the batteries 2, refer to Figure 3 to Figure 5 And then described.

[0038] A flexible printed circuit (FPC) 13 is disposed on the battery 2. The flexible printed circuit 13 is formed in a strip shape with the X-axis direction as the longitudinal direction, and thermistors 14 are provided at both ends of the flexible printed circuit 13. In the module 1, the thermistor 14 is not bonded to the battery 2, but is pressed toward the battery 2 by the outer case cover 102.

[0039] One or more buffers (not shown) are accommodated inside the module 1. For example, the buffer is a thin plate-shaped member that can be elastically deformed, and is arranged between adjacent batteries 2 with the arrangement direction of the batteries 2 as the thickness direction. In this embodiment, as an example, buffers are arranged at both ends and the center of the module 1 in the longitudinal direction.

[0040] (2)Battery

[0041] like Figure 3 As shown, the battery 2 includes an electrode body 21, a laminated outer 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 object.

[0042] The laminated outer package 22 accommodates the electrode body 21 and the non-aqueous electrolyte. The positive electrode tab 23 protrudes from the laminated outer package 22 in the positive direction of the Y axis. The negative electrode tab 24 protrudes from the laminated outer package 22 in the negative direction of the Y axis.

[0043] The length L1 of the battery 2 in the Y-axis direction (see Figure 3 ) is, for example, 530 mm to 600 mm. The length L2 of the battery 2 in the X-axis direction (see Figure 3 ) is, for example, 80 mm to 110 mm. The length L3 of the battery 2 in the Z-axis direction (see Figure 5) For example, 7.0mm to 9.0mm.

[0044] (2.1) Electrode body

[0045] The structure of the electrode body 21 is a stacked type. Figure 5 As shown, the electrode body 21 includes a plurality of positive electrode sheets 211, a plurality of negative electrode sheets 212, and a plurality of separators 213. The electrode body 21 is formed by alternately stacking the positive electrode sheets 211 and the negative electrode sheets 212 with the separators 213 interposed therebetween along the Z-axis direction.

[0046] like Figure 4 As shown, the electrode body 21 has an overlapping region R213 in both edge regions in the X-axis direction. In the overlapping region R213, as shown in FIG. Figure 5 As shown, only a plurality of separators 213 overlap each other. In this embodiment, the two overlapping regions R213 have a plurality of welded portions W213. In the welded portions W213, a plurality of separators 213 are welded. A plurality of welded portions W213 are discretely formed along the Y-axis direction. In this embodiment, the length L4 of each of the plurality of welded portions W213 in the Y-axis direction (see Figure 4 ) are the same. The interval L5 between adjacent welded portions W213 in the Y-axis direction (refer to Figure 4 )same.

[0047] The number of each of the positive electrode sheet 211 , the negative electrode sheet 212 , and the separator 213 is not particularly limited, and is appropriately selected according to the purpose of the battery 2 .

[0048] (2.1.1) Positive electrode

[0049] The positive electrode sheet 211 has a positive electrode current collector 2111 (for example, aluminum foil, etc.) and a positive electrode active material layer 2112 supported on both sides 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 absorbs lithium ions from the non-aqueous electrolyte. The positive electrode active material is a known positive electrode active material (for example, LiNiO2, LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 The positive electrode active material layer 2112 may further contain a known conductive material (for example, carbon black), trilithium phosphate, and a known binder (for example, polyvinylidene fluoride).

[0050] (2.1.2) Negative electrode

[0051] The negative electrode sheet 212 has a negative electrode collector 2121 (for example, copper foil, etc.) and a negative electrode active material layer 2122 supported on both sides of the negative electrode collector 2121. The negative electrode active material layer 2122 contains a negative electrode active material. The negative electrode active material absorbs lithium ions as charge carriers from the non-aqueous electrolyte and releases them into the non-aqueous electrolyte during charging and discharging. The negative electrode active material can be a known negative electrode active material (artificial graphite, lithium alloy (for example, LiXM, M is C, Si, Sn, Sb, Al, Mg, Ti, Bi, Ge, Pb or P, etc., X is a natural number)). The negative electrode active material layer 2122 may also contain a known binder (for example, styrene butadiene copolymer, etc.).

[0052] (2.1.3) Separator

[0053] The separator 213 electrically insulates the positive electrode sheet 211 and the negative electrode sheet 212, and provides a path for lithium ions to move between the positive electrode active material layer 2112 and the negative electrode active material layer 2122. As the separator 213, a porous film or the like can be cited. As the material of the porous film, for example, polyethylene, polypropylene, etc. can be cited. The separator 213 can be a single-layer structure or a multi-layer structure.

[0054] (2.2) Laminated outer body

[0055] The laminated outer package 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 this embodiment, the laminated outer package 22 is a single cup structure (see Figure 5 ). The "single cup structure laminated outer package" means a laminated outer package having a bending line, a cup portion (recessed portion) capable of accommodating the entire electrode body, and a flat portion, and being bent along the bending line so that the flat portion covers the recessed portion. The laminated outer package 22 includes a laminate sheet.

[0056] (2.2.1) Laminated sheet

[0057] The laminate sheet has 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 electrode body 21 side. The outer resin layer is laminated on the surface of the metal layer on the side opposite to the electrode body 21 side. The metal layer cuts off the entry and exit of gas (for example, moisture, air, etc.) between the outside of the battery 2 and the inside of the battery 2. The material of the metal layer is metal (for example, aluminum, etc.). The inner resin layer electrically insulates the electrode body 21, the positive electrode tab 23 and the negative electrode tab 24 from the metal layer. The inner resin layer may contain a thermoplastic resin. The outer resin layer improves the durability of the laminate sheet. The outer resin layer may contain a thermoplastic resin. As thermoplastic resins for each of the inner resin layer and the outer resin layer, for example, olefin resins (for example, polypropylene, polyethylene, etc.), polyvinyl chloride, polyvinylidene chloride, etc. can be cited.

[0058] (2.3) Positive electrode tab

[0059] The positive electrode tab 23 is electrically connected to the plurality of positive electrode current collectors 2111. The material of the positive electrode tab 23 may be metal (for example, stainless steel (SUS)). The length L6 of the positive electrode tab 23 in the Y-axis direction (see Figure 3 ) For example, 40mm~50mm.

[0060] (2.4) Negative electrode tab

[0061] The negative electrode tab 24 is electrically connected to the plurality of negative electrode current collectors 2121. Examples of the material of the negative electrode tab 24 include metal (for example, stainless steel (SUS)). The length L7 of the negative electrode tab 24 in the Y-axis direction (see Figure 3 ) For example, 40mm~50mm.

[0062] (2.5) Non-aqueous electrolyte

[0063] The battery 2 includes a non-aqueous electrolyte. The non-aqueous electrolyte is contained in a laminated outer package 22 together with the electrode body 21. The non-aqueous electrolyte is a non-aqueous electrolyte obtained by dissolving or dispersing a supporting salt (e.g., LiPF6, etc.) as an electrolyte in a non-aqueous solvent (e.g., ethyl carbonate, etc.). The non-aqueous electrolyte may also contain various additives (e.g., lithium bis(oxalatoborate, etc.).

[0064] (3) Effect

[0065] As reference Figure 1 to Figure 5 As described above, the battery 2 includes the electrode body 21, the laminated outer body 22, the positive electrode tab 23, and the negative electrode tab 24. The electrode body 21 has an overlapping region R213. The overlapping region R213 has a plurality of welded portions W213. The plurality of welded portions W213 are discretely formed along the Y-axis direction.

[0066] Thus, the gas generated between the separator 213 and at least one of the positive electrode sheet 211 and the negative electrode sheet 212 (hereinafter, also referred to as "positive and negative electrode sheets 211, 212") can easily pass through the adjacent welded portions G213 of the overlapping region R213 of the separator 213 (see Figure 4 ) and moves to the outside of the electrode body 21. That is, compared with the past, gas is not easy to accumulate between the separator 213 and the positive and negative electrode sheets 211, 212. As a result, lithium metal is not easy to precipitate on the surfaces of the positive and negative electrode sheets 211, 212. In addition, the plurality of separators 213 are integrated by a plurality of welding parts W213, and the separator 213 is reliably located between the positive electrode sheet 211 and the negative electrode sheet 212. As a result, the occurrence of a short circuit in the battery 2 is suppressed.

[0067] As reference Figure 1 to Figure 5As described above, in the battery 2, the length L4 of each of the plurality of welded portions W213 in the Y-axis direction (see Figure 4 )same.

[0068] Thus, compared with a configuration in which the lengths of the plurality of welded portions W213 in the Y-axis direction are different, the gas generated between the separator 213 and the positive and negative electrode sheets 211 and 212 can more easily move to the outside of the electrode body 21. As a result, the occurrence of a short circuit in the battery 2 is further suppressed.

[0069] As reference Figure 1 to Figure 5 As described above, in the battery 2, the interval L5 (see Figure 4 )same.

[0070] Thus, compared with a configuration in which the intervals between adjacent welded portions W213 in the Y-axis direction are different, the gas generated between the separator 213 and the positive and negative electrode sheets 211 and 212 is more likely to move to the outside of the electrode body 21. As a result, the occurrence of a short circuit in the battery 2 is further suppressed.

[0071] As reference Figure 1 to Figure 5 As described above, in the battery 2 , both of the two overlapping regions R213 have a plurality of welded portions W213 discretely formed along the Y-axis direction.

[0072] Thus, compared with a configuration in which one of the two overlapping regions R213 has a welded portion W213 continuously formed along the Y-axis direction, the gas generated between the separator 213 and the positive and negative electrode sheets 211 and 212 is more likely to move to the outside of the electrode body 21. As a result, the occurrence of a short circuit in the battery 2 is further suppressed.

[0073] As reference Figure 1 to Figure 5 As described above, the module 1 includes a plurality of batteries 2 and the case 10. The direction of the side where the weld portion W213 is formed in the Y-axis direction is upward.

[0074] In the module 1, the battery 2 is arranged so that one of the two overlapping regions R213 of the plurality of separators 213 is at the top. The gas generated in the battery 2 easily moves upward. Therefore, the gas generated between the separator 213 and the positive and negative electrode sheets 211 and 212 easily moves to the outside above the electrode body 21. As a result, in the module 1, the occurrence of a short circuit is further suppressed.

[0075] (4) Modification

[0076] In this embodiment, the length L4 of each of the plurality of welded portions W213 in the Y-axis direction (see Figure 4) are the same, but the present disclosure is not limited thereto. In the present disclosure, the lengths L4 of the Y-axis direction of the plurality of welded portions W213 may also be different.

[0077] In this embodiment, the interval L5 (see Figure 4 ) are the same, but the present disclosure is not limited thereto. In the present disclosure, the interval L5 (refer to Figure 4 ) may also be different.

[0078] In this embodiment, both of the two overlapping regions R213 have a plurality of welded portions W213 discretely formed along the Y-axis direction, but the present disclosure is not limited thereto. In the present disclosure, one of the two overlapping regions R213 may have a plurality of welded portions W213 discretely formed along the Y-axis direction.

[0079] In the present embodiment, the direction of the side where the weld portion W213 is formed in the Y-axis direction is upward, but the present disclosure is not limited thereto. In the present disclosure, the direction of the side where the weld portion W213 is formed in the Y-axis direction may not be upward.

[0080] In this embodiment, the laminated outer casing 22 is a single cup structure (see Figure 5 ), but the present disclosure is not limited to this. In the present disclosure, the laminated outer casing 22 may also be a double cup structure. "Double cup structure" means a laminated outer casing having a bending line, a first cup portion (recess) capable of accommodating a portion of the electrode body, and a second cup portion (recess) capable of accommodating a portion of the electrode body, and being able to accommodate the entire electrode body in a space formed by the first cup portion and the second cup portion overlapping each other by bending along the bending line.

[0081] In this embodiment, the positive electrode tab 23 protrudes from the laminated outer casing 22 toward the positive direction of the Y axis, and the negative electrode tab 24 protrudes from the laminated outer casing 22 toward the negative direction of the Y axis, 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 also protrude from the laminated outer casing 22 toward the positive direction of the Y axis or the negative direction of the Y axis.

[0082] In this embodiment, the battery 2 is used as a vehicle power supply, but the present disclosure is not limited thereto. In the present disclosure, the battery 2 may be used as a power supply for information processing devices (eg, personal computers, smartphones, etc.), a power supply for power storage, etc.

Claims

1. A battery having: The stacked electrode body is formed by alternately stacking positive and negative electrode sheets in the stacking direction with separators between them. A laminated outer package housing the electrode body; a positive electrode tab, protruding from the laminated outer package toward one side in a first direction orthogonal to the stacking direction, and electrically connected to the plurality of positive electrode sheets; and a negative electrode tab, protruding from the laminated outer package toward one side or the other side in the first direction, and electrically connected to the plurality of negative electrode sheets, The electrode body has overlapping regions where only a plurality of separators overlap each other in both edge regions in a second direction perpendicular to the stacking direction and the first direction. At least one of the two overlapping regions has a plurality of welded portions where a plurality of the separators are welded together. The plurality of welded portions are discretely formed along the first direction.

2. The battery according to claim 1, The plurality of welded portions have the same length in the first direction.

3. The battery according to claim 2, The intervals between adjacent welded portions in the first direction are equal among the plurality of welded portions.

4. The battery according to claim 1, Both of the two overlapping regions have a plurality of the welded portions discretely formed along the first direction.

5. A module comprising: A plurality of batteries according to any one of claims 1 to 4; and A housing for housing a plurality of the batteries, Of the second directions, the direction on the side where the welded portion is formed is upward.

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