Battery pack

Abstract

To provide a reliable battery pack.SOLUTION: A prismatic secondary battery includes an electrode body including a positive electrode and a negative electrode, and a battery case that houses the electrode body. The battery case includes a first wall portion and a second wall portion that face each other in a second direction perpendicular to the first direction. The first wall portion is provided with a gas exhaust valve that breaks when the pressure inside the battery case reaches or exceeds a first pressure value to exhaust gas inside the battery case to the outside of the battery case. The adjacent member has a first surface that faces the outer surface of the first wall portion, and a space is formed in the adjacent member at a position facing the gas exhaust valve. A groove portion that communicates with the space is formed in the first surface of the adjacent member. When the pressure inside the battery case rises, a part of the first wall portion deforms toward the outside of the battery case along the groove portion before the pressure reaches the first pressure value at which the gas exhaust valve breaks.SELECTED DRAWING: Figure 14

Description

Technical Field

[0001] This technology relates to a battery pack.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2023-47009 (Patent Document 1) describes providing a plurality of recesses on the surface of a cooling plate on the battery module side in a fixing structure between a battery module and a cooling plate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the pressure inside the battery case rises, it has been conventionally practiced to break a gas discharge valve provided at a predetermined position. From the viewpoint of improving the reliability of the battery, it is required to secure a gas path towards the gas discharge valve inside the battery case.

[0005] An object of this technology is to provide a highly reliable battery pack.

Means for Solving the Problems

[0006] This technology provides the following battery pack.

[0007] [1] A battery pack comprising a plurality of rectangular secondary batteries arranged in a first direction and an adjacent member disposed on the rectangular secondary batteries, the rectangular secondary battery including an electrode body including a positive electrode and a negative electrode, and a battery case housing the electrode body, the battery case including a first wall portion and a second wall portion facing each other in a second direction orthogonal to the first direction, the first wall portion being provided with a gas discharge valve that breaks when the pressure in the battery case becomes equal to or higher than a first pressure value and discharges the gas in the battery case to the outside of the battery case, the adjacent member having a first surface facing the outer surface of the first wall portion, a space being formed at a position of the adjacent member facing the gas discharge valve, a groove portion communicating with the space being formed on the first surface of the adjacent member, and a part of the first wall portion deforming outside the battery case along the groove portion before reaching the first pressure value at which the gas discharge valve breaks when the pressure in the battery case rises.

[0008] [2] The battery case according to [1], wherein the battery case includes a pair of third wall portions facing each other in the first direction, and the plurality of rectangular secondary batteries are arranged such that the third wall portions of each of the plurality of rectangular secondary batteries face each other.

[0009] [3] The battery pack according to [1] or [2], further comprising a second adjacent member disposed on the outer surface side of the second wall portion.

[0010] [4] The battery pack according to any one of [1] to [3], wherein the groove portion is formed so as to reach a portion of the first surface that does not overlap with the electrode body when viewed from the second direction.

[0011] [5] The battery pack according to any one of [1] to [4], wherein the battery case and the adjacent member are each made of metal, and the thickness of the first wall portion in the battery case is equal to or less than the thickness of a portion of the adjacent member where the groove portion is not formed.

[0012] [6] The battery case includes a case body having an opening and a sealing plate for sealing the opening, and the gas discharge valve is provided on the case body. The assembled battery according to any one of [1] to [5].

Advantages of the Invention

[0013] According to the present technology, it is possible to provide a highly reliable assembled battery by securing a gas path toward the gas discharge valve inside the battery case.

Brief Description of the Drawings

[0014]

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Figure 23

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present technology will be described. In the following description, the same or corresponding parts may be denoted by the same reference numerals, and the description thereof may not be repeated.

[0016] In the embodiments described below, when referring to the number, amount, etc., unless otherwise specified, the scope of the present technology is not necessarily limited to such number, amount, etc. Also, in the following embodiments, each component is not necessarily essential for the present technology, unless otherwise specified. Further, the present technology is not limited to those that necessarily exhibit all of the effects described in the present embodiments.

[0017] In this specification, the descriptions of "comprise", "include", and "have" are in an open-ended format. That is, when including a certain configuration, other configurations other than the said configuration may or may not be included.

[0018] In addition, in this specification, when geometric terms and terms representing positional and directional relationships, such as "parallel", "orthogonal", "diagonal 45°", "coaxial", "along", etc. are used, these terms allow for manufacturing errors or slight variations. When terms representing relative positional relationships, such as "upper side", "lower side", etc. are used in this specification, these terms are used to indicate the relative positional relationship in one state, and depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.), the relative positional relationship can be reversed or rotated at any angle.

[0019] In this specification, the "secondary battery" is not limited to a lithium-ion battery and may include other secondary batteries such as a nickel-metal hydride battery and a sodium-ion battery. In this specification, the "electrode" may be a general term for the positive electrode and the negative electrode.

[0020] In the drawings, the longitudinal direction of the lamination plane of the laminated electrode body included in the secondary battery is defined as the X direction. Also, the short side direction of the electrode body as viewed from the X direction is defined as the Y direction, and the longitudinal direction of the electrode body as viewed from the X direction is defined as the Z direction. For ease of understanding of the invention, there are some places where the dimensions of each component in the drawings are shown as changed from the actual dimensions.

[0021] In this specification of the present application, the first direction (Y direction) may be referred to as the "thickness direction" of the secondary battery or the case body, the second direction (Z direction) may be referred to as the "height direction" of the secondary battery or the case body, and the third direction (X direction) may be referred to as the "width direction" of the secondary battery or the case body.

[0022] (Overall Configuration of the Battery) FIG. 1 is a front view of a secondary battery 1 according to one embodiment. FIGS. 2 to 5 are views showing the states of the secondary battery 1 (non-aqueous electrolyte secondary battery) shown in FIG. 1 as viewed from the directions of arrow II, arrow III, arrow IV, and arrow V, respectively. FIG. 6 is a front cross-sectional view of the secondary battery 1 shown in FIG. 1.

[0023] The secondary battery 1 can be mounted on an electric vehicle (BEV: Battery Electric Vehicle), a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle), a hybrid vehicle (HEV: Hybrid Electric Vehicle), and the like. However, the use of the secondary battery 1 is not limited to in-vehicle applications.

[0024] As shown in FIGS. 1 to 6, the secondary battery 1 (prismatic secondary battery) includes a case 100 (battery case), an electrode body 200, electrode terminals 300, and a current collector 400. The case 100 includes a case body 110, a sealing plate 120, and a sealing plate 130.

[0025] When constructing a battery module including the secondary battery 1, a plurality of secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 may be constrained in the stacking direction (Y direction) by a constraining member to form a battery module, or the battery module may be directly supported on the side surface of the case of the battery pack without using a constraining member.

[0026] The case body 110 is made of a cylindrical, preferably rectangular cylindrical member. Thereby, a prismatic secondary battery 1 is obtained. The case body 110 is made of metal. Specifically, the case body 110 is made of aluminum, an aluminum alloy, iron, or an iron alloy.

[0027] As shown in FIGS. 1 and 2, the sealing plate 120 and the sealing plate 130 are respectively provided at both ends of the case body. The case body 110 can be formed into a rectangular cylindrical shape, for example, by bringing the end edges of a bent plate-like member into contact with each other (the joint portion 115 illustrated in FIG. 2) and joining them to each other (for example, laser welding). The corners of the "rectangular cylindrical shape" may have an R shape.

[0028] In the present embodiment, the case body 110 is formed longer in the thickness direction (Y direction) and the height direction (Z direction) of the secondary battery 1 than in the width direction (X direction) of the secondary battery 1. The dimension (width) of the case body 110 in the X direction is preferably about 30 cm or more. Thereby, a relatively large (high-capacity) secondary battery 1 can be configured. The dimension (height) of the case body 110 in the Z direction is preferably about 20 cm or less, more preferably about 15 cm or less, and still more preferably about 10 cm or less. Thereby, a secondary battery 1 with a relatively low height (low height) can be configured, and for example, the mountability on a vehicle is improved.

[0029] The case body 110 includes a pair of first side portions 111 and a pair of second side portions 112. The pair of first side portions 111 constitute a part of the side surface of the case 100. The pair of second side portions 112 constitute the bottom surface portion and the upper surface portion of the case 100. Each of the pair of first side portions 111 and the pair of second side portions 112 is provided so as to intersect with each other. The pair of first side portions 111 and the pair of second side portions 112 are connected at their respective ends. It is desirable that the area of each of the pair of first side portions 111 is larger than that of each of the pair of second side portions 112.

[0030] As shown in FIG. 5, a gas discharge valve 150 is provided in one of the pair of second side portions 112 (first wall portion), that is, the second side portion 112B. In the example of FIG. 5, the gas discharge valve 150 is provided at the central portion in the width direction (X direction) of the secondary battery 1. In the present embodiment, the gas discharge valve 150 is provided on a wall surface different from the sealing plates 120 and 130. The position and shape of the gas discharge valve 150 can be changed as appropriate.

[0031] The thickness of the plate-like member in the gas discharge valve 150 is thinner than the thickness of the plate-like members other than the gas discharge valve 150 of the case body 110. Thereby, when the pressure in the case 100 becomes a predetermined value or more, the gas discharge valve 150 breaks preferentially compared to other portions of the case body 110, and discharges the gas in the case 100 to the outside.

[0032] As shown in FIG. 2, a joint portion 115 is formed in the other second side portion 112A (second wall portion) of the pair of second side portions 112. The joint portion 115 extends in the width direction (X direction) of the secondary battery 1. At the joint portion 115, the end edges of the plate-like members constituting the case body 110 are joined together.

[0033] As shown in FIG. 3, an opening 113 (first opening) is provided at an end portion on the first side in the X direction of the case body 110. The opening 113 is sealed by a sealing plate 120. The joint portion 115 is formed in the opening 113 and the opening 113 is sealed. The opening 113 and the sealing plate 120 have a substantially rectangular shape in which the Y direction is the short side direction and the Z direction is the long side direction. Note that the substantially rectangular shape includes a rectangular shape or a substantially rectangular shape such as a shape in which the corners of the rectangular shape are rounded.

[0034] A negative electrode terminal 301 is provided on the sealing plate 120 (first sealing plate). The position of the negative electrode terminal 301 can be changed as appropriate.

[0035] As shown in FIG. 4, an opening 114 (second opening) is provided at an end portion on the second side opposite to the first side in the X direction of the case body 110. That is, the opening 114 is located at an end portion opposite to the opening 113, and the openings 113 and 114 face each other. The opening 114 is sealed by a sealing plate 130. The joint portion 115 is formed in the opening 114 and the opening 114 is sealed. The opening 114 and the sealing plate 130 have a substantially rectangular shape in which the Y direction is the short side direction and the Z direction is the long side direction.

[0036] A positive electrode terminal 302 and a liquid injection hole 140 are provided on the sealing plate 130 (second sealing plate). The positions of the positive electrode terminal 302 and the liquid injection hole 140 can be changed as appropriate.

[0037] The sealing plate 120 and the sealing plate 130 are made of metal. Specifically, the sealing plate 120 and the sealing plate 130 are made of aluminum, an aluminum alloy, iron, an iron alloy, or the like.

[0038] The negative electrode terminal 301 (first electrode terminal) is electrically connected to the negative electrode of the electrode body 200. The negative electrode terminal 301 is attached to the sealing plate 120, that is, the case 100.

[0039] The positive electrode terminal 302 (second electrode terminal) is electrically connected to the positive electrode of the electrode body 200. The positive electrode terminal 302 is attached to the sealing plate 130, that is, the case 100.

[0040] The negative electrode terminal 301 is made of a conductive material (more specifically, a metal), and can be made of, for example, copper or a copper alloy. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface portion of the negative electrode terminal 301.

[0041] The positive electrode terminal 302 is made of a conductive material (more specifically, a metal), and can be made of, for example, aluminum or an aluminum alloy.

[0042] The liquid injection hole 140 is sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet and other metal members can be used.

[0043] The electrode body 200 is a flat electrode body in which a positive electrode plate and a negative electrode plate described later are laminated. Note that the electrode body 200 may include a plurality of electrode bodies.

[0044] As shown in FIG. 6, the case 100 houses the electrode body 200. In FIG. 6, the first electrode body 201 described later is illustrated. The first electrode body 201 is housed in the case 100 such that its longitudinal direction is parallel to the X direction.

[0045] Specifically, one or more laminated electrode bodies are accommodated together with an electrolyte (electrolyte), which will be described later, inside an insulating sheet 700 disposed within the case 100. As the electrolyte (non-aqueous electrolyte), for example, ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) are mixed in a volume ratio (at 25°C) of 30:30:40, and LiPF6 is dissolved in the non-aqueous solvent at a concentration of 1.2 mol / L, which can be used.

[0046] The first electrode body 201 includes a substantially rectangular main body portion, a negative electrode tab group 220 (first electrode tab group), and a positive electrode tab group 250 (second electrode tab group).

[0047] The main body portion is composed of a negative electrode plate 210 and a positive electrode plate 240, which will be described later. The negative electrode tab group 220 is located at the end of the first electrode body 201 on the first side in the X direction with respect to the main body portion. In the present embodiment, the first side is the side of the sealing plate 120. The positive electrode tab group 250 is located at the end of the first electrode body 201 on the second side in the X direction with respect to the main body portion. In the present embodiment, the second side is the side of the sealing plate 130.

[0048] The negative electrode tab group 220 and the positive electrode tab group 250 are formed so as to protrude from the central portion of the electrode body 200 toward the sealing plate 120 or the sealing plate 130, respectively.

[0049] The current collector 400 includes a negative electrode current collector 400A and a positive electrode current collector 400B. The negative electrode current collector 400A and the positive electrode current collector 400B are each made of a plate-shaped member. The electrode body 200 is electrically connected to the negative electrode terminal 301 and the positive electrode terminal 302 via the current collector 400.

[0050] The negative electrode current collector 400A is disposed on the sealing plate 120 via a resin-made insulating member. The negative electrode current collector 400A is electrically connected to the negative electrode tab group 220 and the negative electrode terminal 301. The negative electrode current collector 400A is made of a conductive material (more specifically, a metal) and can be made of, for example, copper or a copper alloy. Details of the negative electrode current collector 400A will be described later.

[0051] The positive current collector 400B is disposed on the sealing plate 130 via a resin insulating member. The positive current collector 400B is electrically connected to the positive tab group 250 and the positive terminal 302. The positive current collector 400B is made of a conductive material (more specifically, a metal), and can be made of, for example, aluminum or an aluminum alloy. Note that the positive tab group 250 may be directly electrically connected to the sealing plate 130, or may be electrically connected to the sealing plate 130 via the positive current collector 400B. In this case, the sealing plate 130 may serve as the positive terminal 302. Details of the positive current collector 400B will be described later.

[0052] (Configuration of the electrode body 200) FIG. 7 is a cross-sectional view of the negative electrode plate 210 that constitutes the electrode body 200. As shown in FIG. 7, the negative electrode plate 210 includes a negative electrode core 211 and a negative electrode active material layer 212.

[0053] At one end in the width direction of the negative electrode plate 210, a negative electrode tab 230 that is composed of the negative electrode core 211 and constitutes the negative electrode tab group 220 is provided. When the negative electrode plates 210 are stacked, a plurality of negative electrode tabs 230 are stacked to form the negative electrode tab group 220. The length of each of the negative electrode tabs 230 in the protruding direction in the plurality of negative electrode plates 210 is appropriately adjusted in consideration of the state in which the negative electrode tab group 220 is connected to the negative current collector 400A. Note that the position and shape of the negative electrode tab 230 can be appropriately changed.

[0054] FIG. 8 is a cross-sectional view of the positive electrode plate 240 that constitutes the electrode body 200. As shown in FIG. 8, the positive electrode plate 240 includes a positive electrode core 241 and a positive electrode active material layer 242.

[0055] At one end of the positive electrode plate 240 in the width direction, a positive electrode tab 260 (second electrode tab) that constitutes the positive electrode tab group 250 extends from the positive electrode core 241. When the positive electrode plates 240 are stacked, a plurality of positive electrode tabs 260 are stacked to form the positive electrode tab group 250. The length of each of the positive electrode tabs 260 in the protruding direction in the plurality of positive electrode plates 240 is appropriately adjusted in consideration of the state in which the positive electrode tab group 250 is connected to the positive electrode current collector 400B. Note that the position and shape of the positive electrode tab 260 can be appropriately changed.

[0056] A positive electrode protective layer 243 is provided at the base of the positive electrode tab 260. The positive electrode protective layer 243 does not necessarily have to be provided at the base of the positive electrode tab 260.

[0057] The electrode body 200 may be a wound electrode body in which a long negative electrode plate 210 and a positive electrode plate 240 are stacked and wound via a separator (not shown), or may be a stacked electrode body in which rectangular negative electrode plates 210 and positive electrode plates 240 are alternately stacked. The separator can be composed of, for example, a polyolefin microporous membrane.

[0058] (Connection structure between the electrode body 200 and the current collector 400) FIG. 9 is a cross-sectional view taken along line IX-IX of the secondary battery shown in FIG. 1. As shown in FIG. 9, the electrode body 200 includes a first electrode body 201 and a second electrode body 202. Each of the first electrode body 201 and the second electrode body 202 includes a positive electrode (second electrode) and a negative electrode (first electrode). Note that the electrode body 200 may be composed of one electrode body or may be composed of three or more electrode bodies.

[0059] The electrode body 200 is formed by overlapping the first electrode body 201 and the second electrode body 202. The first electrode body 201 and the second electrode body 202 are arranged side by side in the thickness direction (Y direction) of the first electrode body 201 and the second electrode body 202.

[0060] The first electrode body 201 includes a negative electrode tab group 220. The negative electrode tab group 220 is electrically connected to a current collector 410 (negative electrode current collector) at a first end portion 205 in the X direction. The second electrode body 202 includes a negative electrode tab group 270. The negative electrode tab group 270 is electrically connected to a current collector 430 (negative electrode current collector) at a third end portion 207 in the X direction.

[0061] The negative electrode tab group 220 has a curved portion 221 and a tip portion 222. The curved portion 221 is a portion where the negative electrode tab group 220 is curved on the side to which the first electrode is connected with respect to the tip portion 222. The tip portion 222 is a portion located at an end portion on the side opposite to the side to which the first electrode of the negative electrode tab group 220 is connected.

[0062] The negative electrode tab group 270 has a curved portion 271 and a tip portion 272. The curved portion 271 is a portion where the negative electrode tab group 270 is curved on the side to which the first electrode is connected with respect to the tip portion 272. The tip portion 272 is a portion located at an end portion on the side opposite to the side to which the first electrode of the negative electrode tab group 270 is connected.

[0063] Each of the negative electrode tab group 220 and the negative electrode tab group 270 is curved in opposite directions such that the tip portions 222 and 272 approach each other. In the present embodiment, the tip portions 222 and 272 are separated, but the present invention is not limited to this configuration, and the tip portions 222 and 272 may be in contact with each other.

[0064] The negative electrode current collector 400A electrically connects the negative electrode terminal 301 to the negative electrode tab group 220 and the negative electrode tab group 270. The negative electrode current collector 400A in the present embodiment is connected to the negative electrode terminal 301 between the electrode body 200 and the sealing plate 120.

[0065] The negative electrode current collector 400A includes the current collector 410 and the current collector 430, and the current collector 440.

[0066] The current collector 410 is a plate-shaped member. The current collector 410 has a longitudinal direction in the Z direction and a short-side direction in the Y direction. The current collector 430 is a plate-shaped member. The current collector 430 has a longitudinal direction in the Z direction and a short-side direction in the Y direction. The current collectors 410 and 430 are arranged in parallel in the X direction. Thus, the current collectors 410 and 430 are constituted by separate components.

[0067] The negative tab groups 220 and 270 are respectively joined to the current collectors 410 and 430. The joining of the negative tab groups 220 and 270 to the current collectors 410 and 430 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, caulking, or the like. In the present embodiment, the negative tab group 220 and the current collector 410, and the negative tab group 270 and the current collector 430 are joined by, for example, ultrasonic bonding.

[0068] The current collector 440 is joined to the current collectors 410 and 430 at a joining location (not shown) located at the end in the Z direction. The current collector 440 is connected to the negative terminal 301. The connection between the current collector 440 and the negative terminal 301 can be formed by, for example, caulking and / or welding.

[0069] The negative terminal 301 is provided so as to be exposed outside the sealing plate 120 and reach the current collector 440 of the negative current collector 400A provided on the inner surface side of the sealing plate 120. The negative terminal 301 is connected to a plate-shaped member 303.

[0070] The plate-shaped member 303 is located outside the sealing plate 120. The plate-shaped member 303 is arranged along the sealing plate 120. The plate-shaped member 303 has conductivity. The plate-shaped member 303 is arranged to secure a connection area with a bus bar or the like that electrically connects the secondary battery 1 to another adjacent secondary battery. The connection between the negative terminal 301 and the plate-shaped member 303 can be formed by, for example, laser welding.

[0071] An insulating member 510 is disposed between the plate-like member 303 and the sealing plate 120. An insulating member 520 is disposed between the negative electrode terminal 301 and the sealing plate 120. An insulating member 530 is disposed between the current collector 440 and the sealing plate 120.

[0072] However, the negative electrode terminal 301 may be electrically connected to the sealing plate 120. Further, the sealing plate 120 may serve as the negative electrode terminal 301.

[0073] A spacer 600 is disposed between the sealing plate 120 and the main body portion of the electrode body 200 (not including the negative electrode tab group 220). The spacer 600 is composed of an insulating resin member. The spacer 600 includes a first component 610 and a second component 620. The first component 610 and the second component 620 are engaged with each other at engaging portions (not shown) at both ends in the Z direction.

[0074] The first component 610 and the second component 620 protrude in the Y direction at the end portion on the electrode body 200 side in the X direction. Thereby, when the spacer 600 bends the bending portions 221 and 271, the spacer 600 serves as a guide so that the bending portions 221 and 271 can be easily bent.

[0075] A resin insulating sheet 700 (electrode body holder) is disposed between the electrode body 200 and the case main body 110. The insulating sheet 700 can be formed of, for example, resin. More specifically, the material of the insulating sheet 700 is, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0076] FIG. 10 is a cross-sectional view taken along the line X-X of the secondary battery shown in FIG. 1. The connection structure between the electrode body 200 and the current collector 400 on the positive electrode side of the secondary battery 1 in the present embodiment is different from the configuration on the negative electrode side in that the portions corresponding to the current collectors 410 and 430 on the negative electrode side are formed of a single component (current collector 420).

[0077] The first electrode body 201 includes a positive electrode tab group 250. The positive electrode tab group 250 is electrically connected to a current collector 420 (positive electrode current collector) at the second end portion 206 in the X direction. The second electrode body 202 includes a positive electrode tab group 280. The positive electrode tab group 280 is electrically connected to a current collector 420 (positive electrode current collector) at the fourth end portion 208 in the X direction.

[0078] The positive electrode tab group 250 has a curved portion 251 and a tip portion 252. The curved portion 251 is a portion where the positive electrode tab group 250 is curved on the side to which the second electrode is connected with respect to the tip portion 252. The tip portion 252 is a portion located at the end of the positive electrode tab group 250 on the side opposite to the side to which the second electrode is connected.

[0079] The positive electrode tab group 280 has a curved portion 281 and a tip portion 282. The curved portion 281 is a portion where the positive electrode tab group 280 is curved on the side to which the second electrode is connected with respect to the tip portion 282. The tip portion 282 is a portion located at the end of the positive electrode tab group 280 on the side opposite to the side to which the second electrode is connected.

[0080] Each of the positive electrode tab group 250 and the positive electrode tab group 280 is curved in opposite directions so that the tip portions 252 and 282 approach each other. In the present embodiment, the tip portions 252 and 272 are separated, but the present invention is not limited to this configuration, and the tip portions 252 and 282 may be in contact with each other.

[0081] The positive electrode current collector 400B electrically connects the positive electrode terminal 302 to the positive electrode tab group 250 and the positive electrode tab group 280. The positive electrode current collector 400B in the present embodiment is connected to the positive electrode terminal 302 between the electrode body 200 and the sealing plate 130.

[0082] The positive electrode current collector 400B includes a current collector 420 and a current collector 450.

[0083] The current collector 420 is a plate-shaped member. The current collector 420 has a longitudinal direction in the Z direction and a short-side direction in the Y direction. The current collector 420 is composed of a single integrated part.

[0084] The positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 which is composed of a single part at a joining location 421 described later. The joining location 421 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, caulking, or the like. In the present embodiment, the positive electrode tab group 250, the positive electrode tab group 280, and the current collector 420 are joined by, for example, ultrasonic bonding.

[0085] The current collector 450 is joined to the current collector 420 at a joining location (not shown) located at the end in the Z direction. The current collector 450 is connected to the positive electrode terminal 302. The connection between the current collector 450 and the positive electrode terminal 302 can be formed, for example, by caulking and / or welding.

[0086] The positive electrode terminal 302 is provided so as to be exposed outside the sealing plate 130 and reach the current collector 450 of the positive electrode current collector 400B provided on the inner surface side of the sealing plate 130. The positive electrode terminal 302 is connected to a plate-shaped member 304.

[0087] The plate-shaped member 304 is located outside the sealing plate 130. The plate-shaped member 304 is arranged along the sealing plate 130. The plate-shaped member 304 has conductivity. The plate-shaped member 304 is arranged to ensure a connection area with a bus bar or the like that electrically connects the secondary battery 1 to another adjacent secondary battery. The connection between the positive electrode terminal 302 and the plate-shaped member 304 can be formed, for example, by laser welding.

[0088] An insulating member 510 is arranged between the plate-shaped member 304 and the sealing plate 130. An insulating member 520 is arranged between the positive electrode terminal 302 and the sealing plate 130. An insulating member 530 is arranged between the current collector 450 and the sealing plate 130.

[0089] However, the positive electrode terminal 302 may be electrically connected to the sealing plate 130. Alternatively, the sealing plate 130 may serve as the positive electrode terminal 302.

[0090] A spacer 600 is disposed between the sealing plate 130 and the main body portion of the electrode body 200 (excluding the positive electrode tab groups 250 and 280). The spacer 600 is made of an insulating resin member. The spacer 600 includes a first component 610 and a second component 620. The first component 610 and the second component 620 are engaged with each other at engaging portions (not shown) at both ends in the Z direction.

[0091] The first component 610 and the second component 620 protrude in the Y direction at the end portions on the electrode body 200 side in the X direction. Thereby, when the curved portions 251 and 281 are curved, the spacer 600 serves as a guide so that the curved portions 251 and 281 can be easily curved.

[0092] An insulating sheet 700 (electrode body holder) made of resin is disposed between the electrode body 200 and the case body 110.

[0093] (Configuration of the assembled battery) FIG. 11 is a perspective view of an assembled battery according to one embodiment. As shown in FIG. 11, in the assembled battery, a plurality of secondary batteries 1 are arranged in the Y direction. The plurality of secondary batteries 1 are arranged such that the first side surface portions 111 (third wall portions) of each face each other.

[0094] A plate member 800 (adjacent member) is disposed on the second side surface portion 112B provided with the gas discharge valve 150. The upper surface (first surface) of the plate member 800 faces the second side surface portion 112B of the secondary battery 1.

[0095] On the upper surface of the plate member 800, a groove portion 810 is formed. A space 820 is formed in a portion of the plate member 800 that faces the gas discharge valve 150. The space 820 may be formed by providing a through hole in the plate member 800, or by providing a recess in the plate member 800 that faces the gas discharge valve 150 (in this case, for example, extending the recess in the Y direction to communicate with the external space and making it function as a gas duct). Alternatively, the plate member 800 may be divided into two, and the space 820 may be provided therebetween. In any case, the space 820 is formed in a portion that faces the gas discharge valve 150. Further, the groove portion 810 communicates with the space 820 that faces the gas discharge valve 150.

[0096] FIG. 12 is a front cross-sectional view of the secondary battery 1 and the plate members 800 and 900, and FIG. 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12.

[0097] As shown in FIGS. 12 and 13, a plate member 900 (second adjacent member) is disposed on the outer surface side of the second side surface portion 112A (second wall portion) that constitutes the upper surface portion of the case body 110. The plate members 800 and 900 are disposed so as to extend parallel to the stacking direction (Y direction) of the secondary battery 1.

[0098] The case 100 and the plate members 800 and 900 may be in direct contact, or may be indirectly in contact with each other with other members such as an insulating film or a sheet interposed therebetween. Further, the case 100 may be covered with a resin film.

[0099] The thickness of the case body 110 that constitutes the second side surface portions 112A and 112B is preferably about 0.1 mm or more and 1 mm or less (more preferably 0.7 mm or less).

[0100] The plate member 800 is preferably made of metal, and its thickness (the portion where the groove portion 810 is not formed) is more preferably about 1 mm or more (more preferably 3 mm or more) and 10 mm or less.

[0101] The case body 110 and the plate member 800 are each made of metal, and it is preferable that the thickness of the second side surface portion 112B in the case body 110 is equal to or less than the thickness of the portion in the plate member 800 where the groove portion 810 is not formed.

[0102] However, the materials, thicknesses, etc. of the case body 110 and the plate member 800 are not limited to the above ranges and can be changed as appropriate. Also, as an adjacent member in place of the plate members 800 and 900, for example, a block-shaped member may be arranged.

[0103] Also, the plate member 900 (second adjacent member) adjacent to the second side surface portion 112A does not necessarily have to be provided.

[0104] FIG. 14 is a front cross-sectional view of the secondary battery 1 and the plate members 800 and 900 in a state where the internal pressure of the case 100 has increased and the gas discharge valve 150 is operating, and FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 14.

[0105] When the pressure inside the case 100 increases, the portion not restrained by the adjacent member in the case 100 expands. In the assembled battery according to the present embodiment, since the groove portion 810 is provided in the plate member 800 adjacent to the second side surface portion 112B of the case 100, as shown in FIGS. 14 and 15, a part of the bottom surface portion (second side surface portion 112B) of the case body 110 deforms outward of the case 100 along the groove portion 810.

[0106] In the example of this embodiment, as shown in FIG. 14, the groove portion 810 reaches a portion on the upper surface (first surface) of the plate member 800 that does not overlap with the electrode body 200 when viewed from the Z direction (second direction), that is, reaches a region closer to the sealing plates 120 and 130 than the X-direction end face of the main body portion (excluding the tab portion) of the electrode body 200. Therefore, as indicated by the arrow in FIG. 14, the gas discharged from the X-direction end face of the main body portion of the electrode body 200 flows from the space between the main body portion of the electrode body 200 and the sealing plates 120 and 130 into the gap formed between the electrode body 200 formed along the groove portion 810 and the bottom surface portion (second side surface portion 112B) of the case main body 110, ensuring a path to reach the gas discharge valve 150.

[0107] By causing the deformation of the above-described second side surface portion 112B to occur before reaching the pressure (first pressure value) at which the gas discharge valve 150 breaks (causing the case main body 110 to deform at a lower pressure), a space along the groove portion 810 can be formed between the inner surface of the case main body 110 and the electrode body 200 inside the case 100, ensuring a discharge path leading to the gas discharge valve 150. As a result, cracking of the case 100 at unintended locations is suppressed, and a highly reliable assembled battery in which the gas discharge valve 150 operates stably can be obtained.

[0108] In the example of this embodiment, the pair of first side surface portions 111 of the case main body 110 are constrained by the adjacent secondary batteries 1, and the upper surface portion (second side surface portion 112A) of the case main body 110 is constrained by the plate member 900. Also, the thickness of the sealing plates 120 and 130 is greater than the thickness of the second side surface portion 112B of the case main body 110. Therefore, when the internal pressure of the case 100 rises, the portion of the bottom surface portion (second side surface portion 112B) of the case main body 110 that is not constrained by the plate member 800 is likely to deform outward preferentially.

[0109] However, the scope of the present technology is not limited to this, and the wall surfaces other than the bottom surface portion (second side surface portion 112B) of the case main body 110 do not necessarily have to be constrained, or the thickness of the sealing plates 120 and 130 may be equal to or less than the thickness of the second side surface portion 112B.

[0110] (Arrangement example of the groove portion 810) Figs. 16 to 20 are diagrams showing arrangement examples of the groove portion 810. As shown in Figs. 16 to 20, the groove portion 810 may be provided in one row for each case body 110 (Fig. 16), or may be provided in multiple rows (Figs. 17 to 20). The groove portion 810 may extend in the width direction (X direction) of the secondary battery 1 (Figs. 16, 17, 19), may extend in an oblique direction that obliquely intersects the X direction (Fig. 18), or a combination of the groove portion 810 extending in the X direction and the groove portion 810 extending in the oblique direction may be used (Fig. 20). Note that the arrangement of the groove portion 810 is not limited to those illustrated in Figs. 16 to 20.

[0111] It is preferable that at least a part of the gas discharge valve 150 is arranged in the central region of the second side surface portion 112B. Here, the "central region" means a region within ±10% with respect to the total length of the case 100 in the X direction from the center of the case 100 in the X direction, that is, a region from the end of the case 100 that is 40% or more and 60% or less with respect to the total length (L1) of the case 100 in the X direction (L2 ≦ 1 / 5L1).

[0112] The circular thin portion constituting the gas discharge valve 150 may be formed in a planar shape or a dome shape. Further, instead of the circular thin portion, for example, the gas discharge valve 150 may be constituted by an annular groove or a linear groove (horizontal line, vertical line, cross, etc.).

[0113] In the examples of Figs. 16 to 20, the total length of the case 100 in the X direction and the width of the plate member 800 in the X direction are substantially the same, but the width of the plate member 800 in the X direction may be longer than the total length (L1) of the case 100, or may be shorter than the total length (L1) of the case 100.

[0114] (Cross-sectional shape of the groove portion 810) Figs. 21 to 23 are diagrams showing examples of the cross-sectional shape of the groove portion 810. As shown in Figs. 21 to 23, the cross-sectional shape of the groove portion 810 may be an inverted trapezoidal shape (Fig. 21), a rectangular shape (Fig. 22), or an arc shape (Fig. 23). Note that the cross-sectional shape of the groove portion 810 is not limited to those illustrated in Figs. 21 to 23.

[0115] The widths (B1, B2, B3) of the groove portion 810 are preferably about 3 mm or more, and more preferably about 5 mm or more. As an example, the width of the groove portion 810 is about 20 mm or less. As an example, the width of the groove portion 810 is about 10% or more and 50% or less of the width in the thickness direction (Y direction) of the case 100.

[0116] The depths (D1, D2, D3) of the groove portion 810 are preferably 0.5 mm or more, and more preferably about 1 mm or more. As an example, the depth of the groove portion 810 is about 3 mm or less. As an example, the depth of the groove portion 810 is about 50% or more and 300% or less of the thickness of the second side surface portion 112B (portion other than the gas discharge valve 150) of the case body 110.

[0117] As described above, the embodiments of the present technology have been described. It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present technology is indicated by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0118] 1 Secondary battery, 100 Case, 110 Case body, 111 First side face, 112, 112A, 112B Second side faces, 113, 114 Openings, 115 Joint, 120, 130 Sealing plates, 140 Liquid injection hole, 150 Gas discharge valve, 200 Electrode body, 201 First electrode body, 202 Second electrode body, 205 First end, 206 Second end, 207 Third end, 208 Fourth end, 210 Negative electrode plate, 211 Negative electrode core, 212 Negative electrode active material layer, 220, 270 Negative electrode tab groups, 221, 271 Curved parts, 222, 272 Tip parts, 230 Negative electrode tab, 240 Positive electrode plate, 241 Positive electrode core, 242 Positive electrode active material layer, 243 Positive electrode protective layer, 250, 280 Positive electrode tab groups, 251, 281 Curved parts, 252, 282 Tip parts, 260 Positive electrode tab, 300 Electrode terminal, 301 Negative electrode terminal, 302 Positive electrode terminal, 303, 304 Plate-like members, 400 Current collector, 400A Negative electrode current collector, 400B Positive electrode current collector, 410, 420, 430, 440, 450 Current collectors, 510, 520, 530 Insulating members, 600 Spacer, 610 First component, 620 Second component, 700 Insulating sheet, 800, 900 Plate members, 810 Groove part, 820 Space.

Claims

1. A plurality of rectangular secondary batteries arranged in a first direction, and an adjacent member disposed on the rectangular secondary battery, wherein the rectangular secondary battery includes an electrode body including a positive electrode and a negative electrode, and a battery case housing the electrode body, the battery case includes a first wall portion and a second wall portion facing each other in a second direction orthogonal to the first direction, the first wall portion is provided with a gas discharge valve that breaks when the pressure in the battery case becomes equal to or higher than a first pressure value, and discharges the gas in the battery case to the outside of the battery case, the adjacent member has a first surface facing the outer surface of the first wall portion, a space is formed at a position of the adjacent member facing the gas discharge valve, a groove portion communicating with the space is formed on the first surface of the adjacent member, a battery pack in which a part of the first wall portion deforms outside the battery case along the groove portion before reaching the first pressure value at which the gas discharge valve breaks when the pressure in the battery case rises.

2. the battery case includes a pair of third wall portions facing each other in the first direction, The battery pack according to claim 1, wherein the plurality of rectangular secondary batteries are arranged such that the third wall portions of each of the plurality of rectangular secondary batteries face each other.

3. The battery pack according to claim 1 or claim 2, further comprising a second adjacent member disposed on the outer surface side of the second wall portion.

4. The battery pack according to claim 1 or claim 2, wherein the groove portion is formed so as to reach a portion of the first surface that does not overlap the electrode body when viewed from the second direction.

5. the battery case and the adjacent member are each constituted by metal, The battery pack according to claim 1 or claim 2, wherein the thickness of the first wall portion in the battery case is equal to or less than the thickness of a portion of the adjacent member where the groove portion is not formed.

6. the battery case includes a case body having an opening and a sealing plate sealing the opening, The battery pack according to claim 1 or claim 2, wherein the gas discharge valve is provided in the case body.

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