Non-aqueous electrolyte secondary battery, battery pack, and vehicle

Abstract

To provide a non-aqueous electrolyte secondary battery with high reliability, a battery pack having them, and a vehicle.SOLUTION: A case housing an electrode body and an electrolyte, contains: a case main body having a first open and a second open to both end parts of one of a first direction; and a first sealing plate and a second sealing plate that seal a first open and a second open. An electrode terminal is attached to any one of the first sealing plate and the second sealing plate. In a second direction orthogonal to the first direction, the first electrode is longer than the second electrode. The first and second electrodes are alternately laminated to a third direction orthogonal to the first and second directions. A separator includes a multi-folded shape containing a plurality of folded parts provided to an end part of the first and second electrodes in the second direction. When a non-aqueous electrolyte secondary battery is mounted to a vehicle so that the second direction is directed to a vertical direction, the plurality of folding parts of the separator provided to the end part of the second direction of the first electrode is positioned to a lower direction.SELECTED DRAWING: Figure 23

Description

Technical Field

[0001] The present technology relates to a non-aqueous electrolyte secondary battery, a battery pack, and a vehicle.

Background Art

[0002] U.S. Patent Application Publication No. 2022 / 0302533 (Patent Document 1) discloses a secondary battery having a positive electrode terminal provided at one end of a case and a negative electrode terminal provided at the other end.

[0003] Japanese Patent Application Laid-Open No. 2012-190548 (Patent Document 2) discloses forming a separator interposed between a positive electrode plate and a negative electrode plate of a secondary battery in a ninety-fold shape.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] When the active material drops off from the electrode housed in the case, if the dropped active material reaches the counter electrode, an internal short circuit may occur. From the viewpoint of improving the reliability of the battery, it is required to suppress this.

[0006] An object of the present technology is to provide a highly reliable non-aqueous electrolyte secondary battery, as well as a battery pack and a vehicle including the same.

Means for Solving the Problems

[0007] The present technology provides the following non-aqueous electrolyte secondary battery, battery pack, and vehicle.

[0008] [1]A non-aqueous electrolyte secondary battery mounted on a vehicle, comprising an electrode body in which a first electrode and a second electrode are laminated via a separator, an electrode terminal connected to the first electrode or the second electrode, and a case that houses the electrode body and an electrolytic solution. The case includes a case body having a first opening at one end in a first direction and a second opening at the other end in the first direction, a first sealing plate that seals the first opening, and a second sealing plate that seals the second opening. The electrode terminal is attached to either the first sealing plate or the second sealing plate. In a second direction orthogonal to the first direction, the first electrode is longer than the second electrode, and the first electrode and the second electrode are alternately laminated in a third direction orthogonal to the first direction and the second direction. The separator has a ninety-fold shape including a plurality of bent portions provided at the ends of the first electrode and the second electrode in the second direction. When the non-aqueous electrolyte secondary battery is mounted on the vehicle such that the second direction faces the vertical direction, the plurality of bent portions of the separator provided at the end of the first electrode are located below the first electrode. Non-aqueous electrolyte secondary battery.

[0009] [2]The non-aqueous electrolyte secondary battery according to [1], wherein the first electrode is a negative electrode.

[0010] [3]The non-aqueous electrolyte secondary battery according to [2], wherein the active material of the negative electrode contains carbon.

[0011] [4]The electrode body has a main body portion, a negative electrode tab provided on the first electrode and located on the first sealing plate side with respect to the main body portion, and a positive electrode tab provided on the second electrode and located on the second sealing plate side with respect to the main body portion. The first electrode includes a negative electrode core and a negative electrode active material layer formed on the negative electrode core. The second electrode includes a positive electrode core, a positive electrode active material layer formed on the positive electrode core, and a positive electrode protection layer formed on the positive electrode core. The positive electrode protection layer is located closer to the positive electrode tab side than the positive electrode active material layer. At the end on the positive electrode tab side in the main body portion of the electrode body, the positive electrode protection layer protrudes further toward the positive electrode tab side than the end of the negative electrode active material layer. The non-aqueous electrolyte secondary battery according to [2] or [3].

[0012] [5] The non-aqueous electrolyte secondary battery according to any one of [1] to [3] is a lithium-ion secondary battery.

[0013] [6] The electrode terminal is disposed on one side with respect to the center of the case in the second direction, and the plurality of bent portions are disposed on the opposite side of the electrode terminal with respect to the center. The non-aqueous electrolyte secondary battery according to any one of [1] to [3].

[0014] [7] A liquid injection hole for injecting the electrolytic solution into the case is provided in the first sealing plate or the second sealing plate. The liquid injection hole is disposed on one side with respect to the center of the case in the second direction, and the plurality of bent portions are disposed on the same side as the liquid injection hole with respect to the center. The non-aqueous electrolyte secondary battery according to any one of [1] to [3].

[0015] [8] A discharge valve that preferentially breaks when the pressure in the case becomes a predetermined value or more is provided in the case body. The discharge valve is disposed on one side with respect to the center of the case in the second direction, and the plurality of bent portions are disposed on the same side as the discharge valve with respect to the center. The non-aqueous electrolyte secondary battery according to any one of [1] to [3].

[0016] [9] The case body is formed in a rectangular tube shape by joining the end edges of a plate-like member subjected to bending at a joint portion. The joint portion is disposed on one side with respect to the center of the case in the second direction, and the plurality of bent portions are disposed on the opposite side of the joint portion with respect to the center. The non-aqueous electrolyte secondary battery according to any one of [1] to [3].

[0017]

[10] A battery pack that includes a plurality of non-aqueous electrolyte secondary batteries and is mounted on a vehicle. Each of the plurality of non-aqueous electrolyte secondary batteries includes an electrode body in which a first electrode and a second electrode are laminated via a separator, an electrode terminal connected to the first electrode or the second electrode, and a case that houses the electrode body and an electrolytic solution. The case includes a case body having a first opening at one end in a first direction and a second opening at the other end in the first direction, a first sealing plate that seals the first opening, and a second sealing plate that seals the second opening. The electrode terminal is attached to either the first sealing plate or the second sealing plate. In a second direction orthogonal to the first direction, the first electrode is longer than the second electrode. The first electrode and the second electrode are alternately laminated in a third direction orthogonal to the first direction and the second direction. The separator has a ninety-fold shape including a plurality of bent portions provided at the ends of the first electrode and the second electrode in the second direction. When the battery pack is mounted on the vehicle such that the second direction faces the vertical direction, the plurality of bent portions of the separator provided at the end of the first electrode are located below the first electrode.

[0018]

[11] The battery pack according to

[10] , further including a bus bar that connects the electrode terminals of each of the plurality of non-aqueous electrolyte secondary batteries. The bus bar is disposed on one side with respect to the center of the case in the second direction, and the plurality of bent portions are disposed on the side opposite to the bus bar with respect to the center.

[0019]

[12] A vehicle includes a vehicle body and a battery pack mounted on the vehicle body, the battery pack including a plurality of non-aqueous electrolyte secondary batteries. Each of the plurality of non-aqueous electrolyte secondary batteries includes an electrode body in which a first electrode and a second electrode are laminated via a separator, an electrode terminal connected to the first electrode or the second electrode, and a case that houses the electrode body and an electrolytic solution. The case includes a case body having a first opening at one end in a first direction and a second opening at the other end in the first direction, a first sealing plate that seals the first opening, and a second sealing plate that seals the second opening. The electrode terminal is attached to either the first sealing plate or the second sealing plate. In a second direction orthogonal to the first direction, the first electrode is longer than the second electrode, and the first electrode and the second electrode are alternately laminated in a third direction orthogonal to the first direction and the second direction. The separator has a ninety-fold shape including a plurality of bent portions provided at ends of the first electrode and the second electrode in the second direction. The battery pack is mounted on the vehicle body such that the second direction faces the vertical direction, and the plurality of bent portions of the separator provided at an end of the first electrode are located below the first electrode.

Advantages of the Invention

[0020] According to the present technology, a highly reliable non-aqueous electrolyte secondary battery, as well as a battery pack and a vehicle including the same, can be provided.

Brief Description of the Drawings

[0021]

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Mode for Carrying Out the Invention

[0022] Hereinafter, embodiments of the present technology will be described. In addition, the same reference numerals may be given to the same or corresponding parts, and the description thereof may not be repeated.

[0023] 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 the 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 necessarily limited to those that exhibit all the effects mentioned in the present embodiments.

[0024] In this specification, the descriptions of "comprise", "include", and "have" are in an open-ended form. That is, when a certain configuration is included, other configurations other than the said configuration may or may not be included.

[0025] Also, in this specification, when geometric terms and terms representing positional and directional relationships, such as "parallel", "orthogonal", "45° oblique", "coaxial", "along", etc. are used, those terms allow for manufacturing errors or slight variations. When terms representing relative positional relationships such as "upper side" and "lower side" are used in this specification, those terms are used to indicate the relative positional relationship in one state, and depending on the installation direction of each mechanism (for example, flipping the entire mechanism up and down, etc.), the relative positional relationship can be reversed or rotated at any angle.

[0026] In this specification, the "secondary battery" is not limited to a lithium-ion battery and may include other secondary batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this specification, the "electrode" may be a general term for the positive electrode and the negative electrode.

[0027] Note that 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 configuration in the drawings are shown as changed from the actual dimensions.

[0028] In this specification of the present application, the first direction (X direction) may be referred to as the "width 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 (Y direction) may be referred to as the "thickness direction" of the secondary battery or the case body.

[0029] (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 state 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.

[0030] 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), etc. However, the use of the secondary battery 1 is not limited to in-vehicle use.

[0031] As shown in FIGS. 1 to 6, the secondary battery 1 includes a case 100, an electrode body 200, an electrode terminal 300, and a current collector 400. The case 100 includes a case body 110, a sealing plate 120, and a sealing plate 130.

[0032] When constructing a battery pack 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 pack may be directly supported on the side surface of the case of the battery pack without using a constraining member.

[0033] The case body 110 is made of a cylindrical, preferably rectangular cylindrical member. Thereby, a rectangular secondary battery 1 can be 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, etc.

[0034] As shown in FIGS. 1 and 2, a sealing plate 120 (first wall) and a sealing plate 130 (second wall) are respectively provided at both ends of the case body. The case body 110 can be formed in a square tube shape, for example, by abutting the end edges of plate-like members subjected to bending processing (joint portion 115 illustrated in FIG. 2) and joining them to each other (for example, laser welding). The corners of the "square tube shape" may have an R shape.

[0035] 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 even 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.

[0036] The case body 110 includes a pair of first side faces 111 and a pair of second side faces 112. The pair of first side faces 111 constitutes a part of the side face of the case 100. The pair of second side faces 112 constitutes the bottom face portion and the top face portion of the case 100. Each of the pair of first side faces 111 and the pair of second side faces 112 is provided so as to intersect with each other. The pair of first side faces 111 and the pair of second side faces 112 are connected at their respective ends. It is desirable that each of the pair of first side faces 111 has a larger area than each of the pair of second side faces 112.

[0037] As shown in FIG. 5, a gas discharge valve 150 is provided in one of the pair of second side faces 112, i.e., the second side face 112B. The gas discharge valve 150 extends in the width direction (X direction) of the secondary battery 1. The gas discharge valve 150 extends in the X direction to such an extent that it does not reach both ends from the center of the case body 110 in the X direction. The gas discharge valve 150 can be appropriately changed.

[0038] The thickness of the plate-like member in the gas discharge valve 150 is thinner compared to the thickness of the plate-like members other than the gas discharge valve 150 of the case body 110. As a result, when the pressure inside the case 100 becomes a predetermined value or more, the gas discharge valve 150 breaks preferentially compared to other parts of the case body 110, and discharges the gas inside the case 100 to the outside.

[0039] As shown in FIG. 2, a joint portion 115 is formed on the other second side surface portion 112A of the pair of second side surface 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.

[0040] As shown in FIG. 3, an opening 113 (first opening) is provided at the end of the case body 110 on the first side in the first direction (X direction). The opening 113 is sealed by a sealing plate 120. A joint portion 115 is formed at 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 rectangular shape with rounded corners.

[0041] 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.

[0042] As shown in FIG. 4, an opening 114 (second opening) is provided at the end of the case body 110 on the second side opposite to the first side in the first direction (X direction). That is, the opening 114 is located at the end opposite to the opening 113, and the openings 113 and 114 face each other. The opening 114 is sealed by a sealing plate 130. A joint portion 115 is formed at 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.

[0043] On the sealing plate 130 (the second sealing plate), a positive electrode terminal 302 and a liquid injection hole 160 are provided. The positions of the positive electrode terminal 302 and the liquid injection hole 160 can be changed as appropriate.

[0044] 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, or an iron alloy.

[0045] The negative electrode terminal 301 (the 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.

[0046] The positive electrode terminal 302 (the 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.

[0047] The negative electrode terminal 301 is made of a conductive material (more specifically, 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.

[0048] The positive electrode terminal 302 is made of a conductive material (more specifically, metal), and can be made of, for example, aluminum or an aluminum alloy.

[0049] The liquid injection hole 160 is sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet and other metal members can be used.

[0050] The electrode body 200 is a flat-shaped electrode body in which a positive electrode plate and a negative electrode plate, which will be described later, are laminated. Specifically, the electrode body 200 is a laminated electrode body in which a plurality of positive electrode plates and a plurality of negative electrode plates are alternately laminated via a separator 800 to be described later. The separator 800 can be constituted by, for example, a polyolefin microporous membrane. When the electrode body is a laminated electrode body including a plurality of positive electrode plates and a plurality of negative electrode plates, the positive electrode tabs provided on each positive electrode plate are laminated to form a positive electrode tab group, and the negative electrode tabs provided on each negative electrode plate are laminated to form a negative electrode tab group. Note that the electrode body 200 may include a plurality of laminated electrode bodies.

[0051] As shown in FIG. 6, the case 100 houses the electrode body 200. In FIG. 6, the first electrode body 201 to be 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.

[0052] Specifically, one or more laminated electrode bodies are housed together with an electrolyte (electrolyte), not shown, inside an insulating sheet 700 to be described later disposed in the case 100. As the electrolyte (non-aqueous electrolyte), for example, a non-aqueous solvent in which ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) are mixed at a volume ratio (25 ° C) of 30:30:40, LiPF 6 dissolved at a concentration of 1.2 mol / L can be used.

[0053] 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).

[0054] The main body is composed of a negative electrode plate 210 and a positive electrode plate 240, which will be described later. The negative tab group 220 is located at the end of the first electrode body 201 on the first side in the first direction (X direction) with respect to the main body. In this embodiment, the first side is the side of the sealing plate 120. The positive tab group 250 is located at the end of the first electrode body 201 on the second side in the first direction (X direction) with respect to the main body. In this embodiment, the second side is the side of the sealing plate 130.

[0055] The negative tab group 220 and the positive 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.

[0056] The current collector 400 includes a negative current collector 400A and a positive current collector 400B. The negative current collector 400A and the positive current collector 400B are each made of a plate-shaped member. The electrode body 200 is electrically connected to the negative terminal 301 and the positive terminal 302 through the current collector 400.

[0057] The negative current collector 400A is disposed on the sealing plate 120 via a resin insulating member. The negative current collector 400A is electrically connected to the negative tab group 220 and the negative terminal 301. The negative 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 current collector 400A will be described later.

[0058] 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 electrically connected to the sealing plate 130 directly or through 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.

[0059] (Configuration of the electrode body 200) FIG. 7 is a cross-sectional view of the negative electrode plate 210 (section VII-VII in FIG. 8), and FIG. 8 is a front view showing the negative electrode plate 210.

[0060] As shown in FIG. 8, a plurality of negative electrode tabs 230 (first electrode tabs) made of a negative electrode core 211 are provided at one end in the width direction of the negative electrode plate 210. When the negative electrode plates 210 are stacked, the plurality of negative electrode tabs 230 are stacked to form a negative electrode tab group 220. The length in the protruding direction of each of the negative electrode tabs 230 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 electrode current collector 400A. Note that the shape of the negative electrode tab 230 is not limited to that illustrated in FIG. 7.

[0061] FIG. 9 is a cross-sectional view of the positive electrode plate 240 (section IX-IX in FIG. 10), and FIG. 10 is a front view showing the positive electrode plate 240.

[0062] As shown in FIG. 10, a plurality of positive electrode tabs 260 (second electrode tabs) made of a positive electrode core 241 are provided at one end in the width direction of the formed positive electrode plate 240. When the positive electrode plates 240 are stacked, the plurality of positive electrode tabs 260 are stacked to form a positive electrode tab group 250. The length in the protruding direction of each of the positive electrode tabs 260 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 shape of the positive electrode tab 260 is not limited to that illustrated in FIG. 10.

[0063] 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.

[0064] In a typical example, the thickness of one negative electrode tab 230 is smaller than the thickness of one positive electrode tab 260. In this case, the thickness of the negative electrode tab group 220 is smaller than the thickness of the positive electrode tab group 250.

[0065] (Connection Structure between Electrode Body 200 and Current Collector 400) FIG. 11 is a cross-sectional view taken along the line XI-XI of the secondary battery shown in FIG. 1. As shown in FIG. 11, 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 three or more electrode bodies.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] Each of the negative electrode tab groups 220 and 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 from each other, but the present invention is not limited to this configuration, and the tip portions 222 and 272 may be in contact with each other.

[0071] 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.

[0072] The negative electrode current collector 400A includes a current collector 410, a current collector 430, and a current collector 440.

[0073] The current collector 410 is a plate-like 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-like member. The current collector 430 has a longitudinal direction in the Z direction and a short-side direction in the Y direction. The current collector 410 and the current collector 430 are arranged in parallel in the X direction. As described above, the current collector 410 and the current collector 430 are constituted by separate parts.

[0074] The negative electrode tab group 220 is joined to the current collector 410 at a joining portion 411 described later. The negative electrode tab group 270 is joined to the current collector 430 at a joining portion 431 described later. The joining portions 411 and 431 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, caulking, or the like. In the present embodiment, the negative electrode tab group 220 and the current collector 410, and the negative electrode tab group 270 and the current collector 430 are joined by, for example, ultrasonic joining.

[0075] The current collector 440 is joined to the current collector 410 and the current collector 430 at a joining portion (not shown) located at the end in the Z direction. The current collector 440 is connected to the negative electrode terminal 301. The connection between the current collector 440 and the negative electrode terminal 301 can be formed by, for example, caulking and / or welding.

[0076] The negative electrode terminal 301 is exposed outside the sealing plate 120 and is provided so as to reach the current collector 440 of the negative electrode current collector 400A provided on the inner surface side of the sealing plate 120. The negative electrode terminal 301 is connected to the plate-like member 303.

[0077] The plate-like member 303 is located outside the sealing plate 120. The plate-like member 303 is arranged along the sealing plate 120. The plate-like member 303 has conductivity. The plate-like 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 electrode terminal 301 and the plate-like member 303 can be formed by, for example, laser welding.

[0078] An insulating member 510 is arranged between the plate-like member 303 and the sealing plate 120. An insulating member 520 is arranged between the negative electrode terminal 301 and the sealing plate 120. An insulating member 530 is arranged between the current collector 440 and the sealing plate 120.

[0079] However, the negative electrode terminal 301 may be electrically connected to the sealing plate 120. Also, the sealing plate 120 may serve as the negative electrode terminal 301.

[0080] A spacer 600 is arranged between the sealing plate 120 and the main body portion of the electrode body 200 (the negative electrode tab group 220 is not included). 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.

[0081] The first component 610 and the second component 620 protrude in the Y direction at the end side on the electrode body 200 side in the X direction. Thereby, the spacer 600 serves as a guide so that the curved portions 221, 271 are easily curved when the curved portions 221, 271 are curved.

[0082] An insulating sheet 700 (electrode body holder) made of resin is disposed between the electrode body 200 and the case 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).

[0083] FIG. 12 is a cross-sectional view of the secondary battery shown in FIG. 1 taken along the line XII-XII. 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 negative electrode side configuration in that a portion corresponding to the current collectors 410 and 430 on the negative electrode side is formed of a single component (current collector 420).

[0084] The first electrode body 201 includes a positive electrode tab group 250. The positive electrode tab group 250 is electrically connected to the 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 the current collector 420 (positive electrode current collector) at the fourth end portion 208 in the X direction.

[0085] 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 portion on the side opposite to the side to which the second electrode of the positive electrode tab group 250 is connected.

[0086] 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 portion on the side opposite to the side to which the second electrode of the positive electrode tab group 280 is connected.

[0087] Each of the positive electrode tab groups 250 and 280 is curved in opposite directions such 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.

[0088] 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.

[0089] The positive electrode current collector 400B includes a current collector 420 and a current collector 450.

[0090] The current collector 420 is a plate-like 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 component.

[0091] 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 component, at a joining portion 421 described later. The joining portion 421 can be formed by, for example, 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.

[0092] The current collector 450 is joined to the current collector 420 at a joining portion (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 by, for example, caulking and / or welding.

[0093] 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-like member 304.

[0094] 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 secure a connection area with a bus bar or the like that electrically connects the secondary battery 1 and other adjacent secondary batteries. The connection between the positive electrode terminal 302 and the plate-shaped member 304 can be formed by, for example, laser welding.

[0095] 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.

[0096] However, the positive electrode terminal 302 may be electrically connected to the sealing plate 130. Also, the sealing plate 130 may serve as the positive electrode terminal 302.

[0097] A spacer 600 is arranged 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 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.

[0098] 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 bending portions 251 and 281 are bent, the spacer 600 serves as a guide so that the bending portions 251 and 281 are easily bent.

[0099] A resin insulating sheet 700 (electrode body holder) is arranged between the electrode body 200 and the case body 110.

[0100] (Manufacturing process of the secondary battery 1) Hereinafter, a method for manufacturing a secondary battery according to this embodiment will be described. FIG. 13 is a flowchart showing the method for manufacturing a secondary battery according to this embodiment. FIG. 14 is a perspective view showing a state before two electrode bodies included in the secondary battery according to this embodiment overlap. FIG. 15 is a cross-sectional view taken along line XV-XV of the electrode body and the current collector shown in FIG. 14.

[0101] As shown in FIG. 13, in the method for manufacturing a secondary battery according to this embodiment, first, a first electrode body 201 and a second electrode body 202 are manufactured (step S1). Each of the negative tab group 220, the positive tab group 250, the negative tab group 270, and the positive tab group 280 has a part of its tip cut so that the lengths of the tips are the same when bundled.

[0102] As shown in FIGS. 13 to 15, after manufacturing the first electrode body 201 and the second electrode body 202, the negative tab group 220 is joined to the current collector 410 (step S2). The negative tab group 220 is joined to the current collector 410 at the joining portion 411. Next, the negative tab group 270 is joined to the current collector 430 (step S3). The negative tab group 270 is joined to the current collector 430 at the joining portion 431.

[0103] Next, the first electrode body 201, the current collector 420, and the second electrode body 202 are arranged side by side in this order in a first direction (DR1 direction). The positive tab group 250 is arranged on one side of the current collector 420 in the first direction (DR1 direction). With the positive tab group 280 arranged on the other side of the current collector 420 in the first direction (DR1 direction), the positive tab group 250 and the positive tab group 280 are joined to the current collector 420 (step S4). The positive tab group 250 and the positive tab group 280 are joined to the current collector 420 at the joining portion 421.

[0104] In the height direction of the first electrode body 201 and the second electrode body 202, the current collectors 410, 420, and 430 are arranged offset to one side from the center of the first electrode body 201 and the second electrode body 202. Thereby, since the current collector can be configured to be short, the current collector can be made small.

[0105] Note that the current collectors 410, 420, and 430 are not limited to this configuration. The current collectors 410, 420, and 430 may be disposed at the centers of the first electrode body 201 and the second electrode body 202 in the height direction of the first electrode body 201 and the second electrode body 202. In this case, in the height direction of the first electrode body 201 and the second electrode body 202, each of the negative tab group 220, the positive tab group 250, the negative tab group 270, and the positive tab group 280 is disposed at the center of the first electrode body 201 and the second electrode body 202 in accordance with the current collectors 410, 420, and 430.

[0106] Also, the order of the steps of joining each of the current collectors 410, 420, and 430 to the first electrode body 201 and the second electrode body 202 is not limited to the above, and the order may be changed. The steps of joining each of the current collectors 410 and 430 to the first electrode body 201 and the second electrode body 202 are preferably performed before the step of overlapping the first electrode body 201 and the second electrode body 202, which will be described later, and are preferably performed before the step of joining the current collector 420 to the first electrode body 201 and the second electrode body 202.

[0107] Next, after joining the positive tab group 250 and the positive tab group 280 to the current collector 420, in the thickness direction of the first electrode body 201 and the second electrode body 202 (the direction orthogonal to the DR1 direction in FIGS. 14 and 15), the positive tab group 250 and the positive tab group 280 are bent to overlap the first electrode body 201 and the second electrode body 202 (step S5). That is, the first electrode body 201 and the second electrode body 202 are put together.

[0108] "Stacking the first electrode body and the second electrode body" means that the first electrode body and the second electrode body may be directly stacked, or other members may be arranged between the first electrode body and the second electrode body. Also, the first electrode body and the second electrode body may or may not be fixed by a tape or the like. Furthermore, the first electrode body, the current collector, and the second electrode body do not have to be arranged linearly in the first direction (DR1 direction), and the first electrode body or the second electrode body may be inclined with respect to the current collector in the first direction (DR1 direction).

[0109] The positive electrode tab groups 250 and 280 are bent so that their tip portions face each other. Also, the negative electrode tab groups 220 and 270 are also bent so that their tip portions face each other.

[0110] Figures 13 and 16 are perspective views showing a state in which a holder and a spacer are attached to the electrode body. As shown in Figure 16, next, the spacer 600 and the insulating sheet 700 are assembled to the electrode body 200 (step S6).

[0111] Note that the insulating sheet 700 does not necessarily have to cover the entire surface of the electrode body 200. The insulating sheet 700 preferably covers an area of about 50% or more, more preferably about 70% or more of the outer surface of the electrode body. The insulating sheet 700 preferably covers the entire four surfaces out of the six surfaces of the substantially rectangular parallelepiped (flat shape) electrode body 200, excluding the two surfaces on which the negative electrode tab group 220 and the positive electrode tab group 250 are respectively formed.

[0112] Figure 17 is a perspective view showing a state in which a sealing plate 120 is attached to the current collector on the negative electrode side. Figure 18 is a cross-sectional view taken along the line XVIII-XVIII of the electrode body and the current collector shown in Figure 17.

[0113] As shown in FIGS. 13, 17, and 18, after joining the negative electrode tab group 220 to the current collector 410, joining the negative electrode tab group 270 to the current collector 430, and overlapping the first electrode body 201 and the second electrode body 202, the current collector 410 and the current collector 430 are electrically connected to the negative electrode terminal 301 via the current collector 440 (step S7). Note that step S7 can also be performed before step S6.

[0114] Specifically, the negative electrode tab group 220 and the negative electrode tab group 270 are bent so that the tip portions 222, 272 face each other.

[0115] Attach the negative electrode terminal 301 and the current collector 440 to the sealing plate 120 via an insulating member. Bring the current collector 440 into contact with the current collector 410 and the current collector 430 in the X direction. Note that the connection of the plate-like member 303 to the negative electrode terminal 301 can be made at any timing. The current collector 440 is joined to the current collector 410 and the current collector 430 by laser welding from between the sealing plate 120 and the insulating sheet 700.

[0116] FIG. 19 is a perspective view showing a state in which the electrode body is inserted into the case body. As shown in FIGS. 13 and 19, next, after overlapping the first electrode body 201 and the second electrode body 202, the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 from the opening 113 with the current collector 420 side at the front (step S8).

[0117] By bringing the sealing plate 120 closer to the main body portion of the electrode body 200 (the first electrode body 201 and the second electrode body 202), the negative electrode tab group 220 and the negative electrode tab group 270 are curved. It is preferable that the sealing plate 120 and the case body 110 approach each other by bringing the sealing plate 120 closer to the main body portion of the electrode body 200 disposed in the case body 110. As shown in FIG. 11, the negative electrode tab group 220 and the negative electrode tab group 270 are curved along the shape of the spacer 600 so that the folded portions of the curved portions 221, 271 approach the case body 110 in the Y direction.

[0118] After bringing the sealing plate 120 into contact with the case body 110, temporarily join the sealing plate 120 to the case body 110. By the temporary joining, the sealing plate 120 is partially joined to the opening 113 of the case body 110. Thereby, the sealing plate 120 is positioned with respect to the case body 110.

[0119] When inserting the electrode body 200 into the case body 110, the electrode body 200 may be pulled from the current collector 420 side or may be pushed from the current collector 410 and current collector 430 sides. When the electrode body 200 is pushed from the current collector 410 and current collector 430 sides, the negative tab group 220 and the negative tab group 270 can be curved simultaneously.

[0120] FIG. 20 is a perspective view showing a state in which a sealing plate 130 is attached to the current collector on the positive electrode side. FIG. 21 is a cross-sectional view taken along the line XXI-XXI of the electrode body and the current collector shown in FIG. 20. In FIG. 21, the case body 110 is omitted.

[0121] As shown in FIGS. 13, 20, and 21, after inserting the first electrode body 201 and the second electrode body 202 into the case body 110, electrically connect the current collector 420 to the positive electrode terminal 302 (step S9).

[0122] Specifically, attach the positive electrode terminal 302 and the current collector 450 to the sealing plate 130 via an insulating member. After inserting the first electrode body 201 and the second electrode body 202 into the case body 110, bring the current collector 450 into contact with the current collector 420 protruding from the opening 114 in the X direction. The connection of the plate-like member 304 to the positive electrode terminal 302 may be at any timing.

[0123] As shown in FIG. 21, the positive electrode tab groups 250 and 280 connected to the current collector 420 are bent such that the tip portions 252 and 282 face each other. From the state shown in FIG. 21, the sealing plate 130 is brought into contact with the case body 110. At this time, by bringing the sealing plate 130 closer to the main body portion of the electrode body 200, the positive electrode tab groups 250 and 280 are curved. As shown in FIG. 12, the positive electrode tab groups 250 and 280 are curved along the shape of the spacer 600 such that the folded portions of the curved portions 251 and 281 approach the case body 110 in the Y direction.

[0124] After the sealing plate 130 is brought into contact with the case body 110, the sealing plate 130 is temporarily welded to the case body 110. By the temporary joining, the sealing plate 130 is partially joined to the opening 114 of the case body 110. Thereby, the sealing plate 130 is positioned with respect to the case body 110.

[0125] FIG. 22 is a perspective view showing the configuration of the secondary battery 1. As shown in FIGS. 13 and 22, next, the sealing plate 120 and the sealing plate 130 are joined to the case body 110 (step S10). The sealing plate 120 seals the opening 113 of the case body 110, and the sealing plate 130 seals the opening 114 of the case body 110. Thereby, the first electrode body 201 and the second electrode body 202 are housed in the case 100.

[0126] After the above-described steps, inspections such as a leak inspection are performed (step S11). After the leak inspection, the secondary battery 1 is dried to remove moisture inside the case 100. Then, an electrolytic solution is injected into the case 100 through the injection hole 160. When injecting the electrolytic solution, the case 100 is inclined with the sealing plate 130 upward and the sealing plate 120 downward, and the electrolytic solution is injected into the case 100 through the injection hole 160 of the sealing plate 130. Thereafter, gas venting charging is performed. During the gas venting charging, the injection hole 160 may be temporarily sealed. Thereafter, the injection hole 160 is sealed, and the secondary battery 1 is completed.

[0127] Note that the order of the insertion process of the electrode body 200 and the connection process between the current collectors is not limited to the above-described example. For example, after inserting only a part of the electrode body 200 into the case body 110 (first step) so that the end portion on the opening 113 side in the negative electrode active material layer 212 is disposed outside the case body 110, the negative electrode terminal 301 (first electrode terminal) provided on the sealing plate 120 (first sealing plate) and the negative electrode tab groups 220 and 270 (first electrode tabs) are electrically connected. Then, thereafter, the electrode body 200 may be inserted into the case body 110 (second step) until the end portion on the opening 113 side in the negative electrode active material layer 212 is disposed inside the case body 110. That is, the negative electrode terminal 301 and the electrode body 200 can be electrically connected during the insertion process of the electrode body 200 into the case body 110.

[0128] In the present embodiment, by providing the negative electrode tab groups 220 and the positive electrode tab groups 250 on the first electrode body 201 and providing the negative electrode tab groups 270 and the positive electrode tab groups 280 on the second electrode body 202, the first electrode body 201 and the second electrode body 202 can have separate electrode tabs. With this configuration, compared with the case where the first electrode body 201 and the second electrode body 202 form an integrated electrode tab and this electrode tab is bent, the electrode tab can be shortened. As a result, since the occupied volume of the electrode tab can be reduced, the energy density of the secondary battery 1 can be improved. Further, the configuration in which the first electrode body 201 and the second electrode body 202 are provided with separate electrode tabs is easier to bend the electrode tabs compared with the case where the first electrode body 201 and the second electrode body 202 form an integrated electrode tab, so that the electrode tab and the current collector can be easily joined and the secondary battery can be stably manufactured. In particular, since the secondary battery 1 can be stably manufactured, the reliability of the connection portion between the electrode tab and the current collector can be increased.

[0129] (Shape or arrangement of the separator 800) FIG. 23 is a schematic diagram showing the shapes of the negative electrode plate 210, the positive electrode plate 240, and the separator 800.

[0130] As shown in FIG. 23, in the Z direction (the second direction), the negative electrode plate 210 (the first electrode) is formed longer than the positive electrode plate 240 (the second electrode). The negative electrode plate 210 and the positive electrode plate 240 are alternately laminated in the Y direction (the third direction).

[0131] The separator 800 has a ninety-fold shape including a plurality of bent portions 810 and 820. The bent portion 810 is provided at the Z-direction end of the negative electrode plate 210, and the bent portion 820 is provided at the Z-direction end of the positive electrode plate 240. The U-shaped bent portions 810 and 820 (folding-back portions) shown in FIG. 23 are an example, and the scope of the present technology is not limited thereto. For example, it may be in the shape of substantially V-shaped bent portions 810 and 820 (folding-back portions) as shown in FIG. 24 described later.

[0132] FIG. 24 is a schematic diagram showing the arrangement of the separator 800 in the secondary battery 1 according to the present embodiment. FIG. 25 is a schematic diagram showing the arrangement of the separator 800A in the secondary battery 1A according to the comparative example.

[0133] Both the secondary batteries 1 and 1A are mounted on the vehicle such that the Z direction faces the vertical direction (substantially vertical direction), and more specifically, the +Z side is on the upper side. At this time, in the secondary battery 1 shown in FIG. 24, the bent portion 810 is located below the negative electrode plate 210 (the first electrode), and the bent portion 820 is located above the positive electrode plate 240 (the second electrode). On the other hand, in the secondary battery 1A shown in FIG. 25, the bent portion 820A is located above the negative electrode plate 210, and the bent portion 810A is located below the positive electrode plate 240.

[0134] As described above, since the negative electrode plate 210 is formed longer than the positive electrode plate 240 in the Z direction, the negative electrode active material is likely to fall off from the negative electrode active material layer 212 of the negative electrode plate 210. Also, generally, the adhesion of the negative electrode active material layer 212 to the negative electrode core 211 is weaker than the adhesion of the positive electrode active material layer 242 to the positive electrode core 241, and the negative electrode active material (especially graphite) tends to be more easily peeled off.

[0135] The negative electrode active material layer 212 may contain, in addition to the negative electrode active material, a binder (such as SBR or CMC) and a conductive member (such as a carbon material). As the negative electrode active material, a carbon material such as graphite, a silicon material such as SiO or SiC, or the like can be used. The negative electrode active material may be a mixture of a plurality of substances.

[0136] As shown in FIGS. 24 and 25, an excess liquid of the electrolytic solution 200A is stored at the bottom of the case 100. When the negative electrode active material layer 212 is immersed in the excess liquid of the electrolytic solution 200A, the active material tends to be more easily peeled off.

[0137] When the conductive active material peeled off from the electrode plate floats in the electrolytic solution 200A and moves to the counter electrode, self-discharge or short circuit may occur inside the case 100.

[0138] On the other hand, in the secondary battery 1 (FIG. 24) according to the present embodiment, since the bent portion 810 of the separator 800 is disposed below the negative electrode plate 210 where the active material is more likely to fall off, compared with the secondary battery 1A (FIG. 25) according to the comparative example, the active material peeled off from the negative electrode active material layer 212 is less likely to float in the case 100, and the possibility of moving to the positive electrode plate 240 is further reduced. As a result, a highly reliable secondary battery 1 in which the occurrence of self-discharge and short circuit defects is suppressed is provided.

[0139] (Liquid level of the excess liquid of the electrolytic solution 200A) FIGS. 26 to 29 are schematic diagrams showing states in which the liquid level height of the excess liquid of the electrolytic solution 200A is different from the state shown in FIG. 24.

[0140] FIG. 26 shows a state before injecting the electrolytic solution 200A after the electrode body 200 is housed in the case 100, FIG. 27 shows a state immediately after injecting the electrolytic solution 200A into the case 100, FIG. 28 shows a state in which the injected electrolytic solution 200A is impregnated into the electrode body 200, and FIG. 29 shows a state in which the secondary battery 1 is charged or discharged.

[0141] As shown in FIGS. 24 and 26 to 29, in each state, the liquid level height of the surplus liquid of the electrolytic solution 200A changes. However, in the usage state of the secondary battery 1 (FIGS. 24 and 27 to 29), the electrolytic solution 200A accumulated below the negative electrode plate 210 is in a state of being sandwiched by the separator 800 folded ninety-nine times. Therefore, even if the negative electrode active material that has fallen off the negative electrode plate 210 floats in the electrolytic solution 200A, it is suppressed from reaching the positive electrode plate 240 which is the counter electrode. In this way, a highly reliable secondary battery 1 is provided.

[0142] (Structure of the end of the electrode body 200) FIG. 30 is a schematic diagram showing the structure of the electrode body 200, and FIG. 31 is an enlarged view of part XXXI in FIG. 30.

[0143] As shown in FIGS. 30 and 31, in the main body part of the electrode body 200, at the end on the side of the positive electrode tab groups 250 and 280, the positive electrode protective layer 243 protrudes toward the positive electrode tab groups 250 and 280 side more than the end of the negative electrode active material layer 212. The positive electrode protective layer 243 protrudes toward the positive electrode tab groups 250 and 280 side (+X side) by a distance G1 more than the end of the negative electrode active material layer 212.

[0144] Here, the positive electrode protective layer 243 protrudes along the X direction (the first direction) connecting the opening 113 and the opening 114 more than the end of the negative electrode active material layer 212. The positive electrode protective layer 243 protrudes along the insertion direction of the electrode body 200 more than the end of the negative electrode active material layer 212. The positive electrode protective layer 243 protrudes along the direction perpendicular to the sealing plates 120 and 130 more than the end of the negative electrode active material layer 212.

[0145] Therefore, when the electrode body 200 is inserted into the case body 110 of the electrode body 200, even if a load such as vibration is applied to cause the electrode body 200 to move within the case body 110 in the vicinity of the end of the negative electrode active material layer 212 located in the +X direction, damage to the end of the negative electrode active material layer 212 can be suppressed, and the dropout of the negative electrode active material can be suppressed. As a result, the reliability of the secondary battery 1 can be further enhanced.

[0146] In a laminated electrode body, since there is a problem of the negative electrode active material falling off when the electrode body 200 is inserted into the case body 110, by adopting the structure shown in FIGS. 30 and 31, a greater effect can be obtained in suppressing damage to the end portion of the negative electrode active material layer 212.

[0147] (Mounting structure on a vehicle) FIG. 32 is a diagram showing a state in which a battery pack including a plurality of secondary batteries 1 is mounted on a vehicle. As shown in FIG. 32, the plurality of secondary batteries 1 are arranged (laminated) along the Y direction and are mounted on the vehicle body 1000 in a state of being constrained in the Y direction by the binding bar 2. Note that the secondary battery 1 may be directly supported by a case (not shown) of the battery pack without using the binding bar 2.

[0148] A bus bar 3 for electrically connecting the electrode terminals 300 of adjacent secondary batteries 1 is provided.

[0149] When the secondary battery 1 is regarded as a single cell and when the secondary battery 1 is regarded as a battery pack in which the secondary batteries 1 are laminated, the upper and lower sides in the state of being mounted on the vehicle body 1000 can be specified as follows, for example.

[0150] The secondary battery 1 according to the present embodiment is mounted on the vehicle body 1000 such that the +Z side is the upward direction.

[0151] As shown in FIG. 32, the electrode terminal 300 and the bus bar 3 are disposed on the upper side (+Z side) with respect to the center (center line O) of the case 100 in the Z direction. The liquid injection hole 160 is disposed on the lower side (-Z side) with respect to the center line O. The gas discharge valve 150 is disposed on the lower side (-Z side) with respect to the center line O. The joint portion 115 of the case body 110 is disposed on the upper side (+Z side) with respect to the center line O.

[0152] On the other hand, the bent portion 810 located below the negative electrode plate 210 is disposed on the lower side (-Z side) with respect to the center line O of the case 100.

[0153] That is, in the example shown in FIG. 32, the bent portion 810 located below the negative electrode plate 210 is disposed on the side opposite to the electrode terminal 300 and the bus bar 3 with respect to the center line O of the case 100, and is disposed on the same side as the liquid injection hole 160 with respect to the center line O, and is disposed on the same side as the gas discharge valve 150 with respect to the center line O, and is disposed on the side opposite to the joint portion 115 with respect to the center line O.

[0154] However, the above-described positional relationship is a relative one that varies depending on the arrangements of the electrode terminal 300 to the bus bar 3, the liquid injection hole 160, the gas discharge valve 150, and the joint portion 115.

[0155] (Modification example of the secondary battery 1) FIG. 33 is a cross-sectional view showing the configuration of a secondary battery according to a modification example. As shown in FIG. 33, in the secondary battery according to the modification example, the tip portions 222 and 272 of each of the negative electrode tab groups 220 and 270 are bent in the same direction in the Y direction.

[0156] Thereafter, the first electrode body 201 and the second electrode body 202 are inserted into the case body, and the sealing plate 120 is brought into contact with the case body. As a result, each of the negative electrode tab groups 220 and 270 is curved in the same direction so that the tip portions 222 and 272 face the same direction. In order to easily curve the tip portions 222 and 272 in the same direction, the third component 630 of the spacer 600 is provided between the negative electrode tab group 220 and the negative electrode tab group 270.

[0157] By making the tip portions 222 and 272 of the negative electrode tab group 220 and the negative electrode tab group 270 curve in the same direction in the Y direction, the first electrode body 201 to which the current collector 410 is attached and the second electrode body 202 to which the current collector 430 is attached can be prepared with the same configuration. As a result, the first electrode body 201 to which the current collector 410 is attached and the second electrode body 202 to which the current collector 430 is attached can be configured as one type, so that the manufacturing process can be simplified.

[0158] In addition, in this embodiment, an example has been described in which the negative electrode terminal 301 is provided on the sealing plate 120 and the positive electrode terminal 302 is provided on the sealing plate 130. However, the scope of the present technology is not limited to this. For example, the electrode terminals 300 of both polarities may be provided on one sealing plate.

[0159] As described above, the embodiments of the present technology have been explained. However, 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 be included.

Description of Reference Numerals

[0160] 1, 1A secondary battery, 2 binding bar, 3 bus bar, 100 case, 110 case body, 111 first side surface portion, 112, 112A, 112B second side surface portions, 113, 114 openings, 115 joint portion, 120, 130 sealing plates, 150 gas discharge valve, 160 liquid injection hole, 200 electrode body, 201 first electrode body, 202 second electrode body, 205 first end portion, 206 second end portion, 207 third end portion, 208 fourth end portion, 210 negative electrode plate, 211 negative electrode core, 212 negative electrode active material layer, 220, 270 negative electrode tab groups, 221, 251, 271, 281 curved portions, 222, 252, 272, 282 tip portions, 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, 260 positive electrode tab, 300 electrode terminals, 301 negative electrode terminal, 302 positive electrode terminal, 303, 304 plate-like members, 400, 410, 420, 430, 440, 450 current collectors, 400A negative electrode current collector, 400B positive electrode current collector, 411, 421, 431 joint locations, 510, 520, 530 insulating members, 600 spacer, 610 first component, 620 second component, 630 third component, 700 insulating sheet, 800, 800A separators, 810, 810A, 820, 820A bent portions.

Claims

1. A non-aqueous electrolyte secondary battery mounted on a vehicle, comprising: an electrode body in which a first electrode and a second electrode are laminated via a separator; an electrode terminal connected to the first electrode or the second electrode; a case that houses the electrode body and an electrolytic solution; the case includes a case body having a first opening at one end in a first direction and a second opening at the other end in the first direction, a first sealing plate that seals the first opening, and a second sealing plate that seals the second opening; the electrode terminal is attached to either the first sealing plate or the second sealing plate; in a second direction orthogonal to the first direction, the first electrode is longer than the second electrode; the first electrode and the second electrode are alternately laminated in a third direction orthogonal to the first direction and the second direction; the separator has a ninety-fold shape including a plurality of bent portions provided at the ends of the first electrode and the second electrode in the second direction; A non-aqueous electrolyte secondary battery, wherein when the non-aqueous electrolyte secondary battery is mounted on the vehicle such that the second direction faces the vertical direction, the plurality of bent portions of the separator provided at the end of the first electrode are located below the first electrode.

2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the first electrode is a negative electrode.

3. The non-aqueous electrolyte secondary battery according to claim 2, wherein the active material of the negative electrode contains carbon.

4. The electrode body has a main body portion, a negative electrode tab provided on the first electrode and located on the first sealing plate side with respect to the main body portion, and a positive electrode tab provided on the second electrode and located on the second sealing plate side with respect to the main body portion; the first electrode includes a negative electrode core body and a negative electrode active material layer formed on the negative electrode core body; the second electrode includes a positive electrode core body, a positive electrode active material layer formed on the positive electrode core body, and a positive electrode protective layer formed on the positive electrode core body; the positive electrode protective layer is located on the positive electrode tab side with respect to the positive electrode active material layer; In the main body portion of the electrode body, at the end on the positive electrode tab side, the positive electrode protective layer protrudes more toward the positive electrode tab side than the end of the negative electrode active material layer. The non-aqueous electrolyte secondary battery according to claim 2 or claim 3.

5. The non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein the non-aqueous electrolyte secondary battery is a lithium ion secondary battery.

6. The electrode terminal is disposed on one side with respect to the center of the case in the second direction. The plurality of bent portions are disposed on the side opposite to the electrode terminal with respect to the center, the non-aqueous electrolyte secondary battery according to any one of claims 1 to 3.

7. A liquid injection hole for injecting the electrolytic solution into the case is provided in the first sealing plate or the second sealing plate. The liquid injection hole is disposed on one side with respect to the center of the case in the second direction. The plurality of bent portions are disposed on the same side as the liquid injection hole with respect to the center, the non-aqueous electrolyte secondary battery according to any one of claims 1 to 3.

8. An exhaust valve that preferentially breaks when the pressure in the case becomes a predetermined value or more is provided in the case body. The exhaust valve is disposed on one side with respect to the center of the case in the second direction. The plurality of bent portions are disposed on the same side as the exhaust valve with respect to the center, the non-aqueous electrolyte secondary battery according to any one of claims 1 to 3.

9. The case body is formed in a rectangular tube shape by joining the end sides of a plate-shaped member subjected to bending processing to each other at a joint portion. The joint portion is disposed on one side with respect to the center of the case in the second direction. The plurality of bent portions are disposed on the side opposite to the joint portion with respect to the center, the non-aqueous electrolyte secondary battery according to any one of claims 1 to 3.

10. A battery pack including a plurality of non-aqueous electrolyte secondary batteries and mounted on a vehicle, Each of the plurality of non-aqueous electrolyte secondary batteries, An electrode body in which a first electrode and a second electrode are laminated via a separator, An electrode terminal connected to the first electrode or the second electrode, And a case that houses the electrode body and the electrolytic solution. The case includes a case body having a first opening at one end in the first direction and a second opening at the other end in the first direction, a first sealing plate that seals the first opening, and a second sealing plate that seals the second opening. The electrode terminal is attached to either the first sealing plate or the second sealing plate. In a second direction orthogonal to the first direction, the first electrode is longer than the second electrode. The first electrode and the second electrode are alternately laminated in a third direction orthogonal to the first direction and the second direction. The separator has a ninety-nine-fold shape including a plurality of bent portions respectively provided at ends of the first electrode and the second electrode in the second direction. A battery pack in which when the battery pack is mounted on the vehicle such that the second direction faces the vertical direction, the plurality of bent portions of the separator provided at an end of the first electrode are located below the first electrode.

11. The battery pack further includes a bus bar connecting electrode terminals of each of the plurality of non-aqueous electrolyte secondary batteries. The bus bar is disposed on one side with respect to the center of the case in the second direction. The battery pack according to claim 10, wherein the plurality of bent portions are disposed on the side opposite to the bus bar with respect to the center.

12. A vehicle body, A battery pack including a plurality of non-aqueous electrolyte secondary batteries and mounted on the vehicle body. Each of the plurality of non-aqueous electrolyte secondary batteries includes an electrode body in which a first electrode and a second electrode are laminated via a separator, an electrode terminal connected to the first electrode or the second electrode, and a case housing the electrode body and an electrolytic solution. The case includes a case body having a first opening at one end in a first direction and a second opening at the other end in the first direction, a first sealing plate sealing the first opening, and a second sealing plate sealing the second opening. The electrode terminal is attached to either the first sealing plate or the second sealing plate. In a second direction orthogonal to the first direction, the first electrode is longer than the second electrode. The first electrode and the second electrode are alternately laminated in a third direction orthogonal to the first direction and the second direction. The separator has a ninety-nine-fold shape including a plurality of bent portions respectively provided at ends of the first electrode and the second electrode in the second direction. The vehicle in which the battery pack is mounted on the vehicle body such that the second direction faces the vertical direction, and the plurality of bent portions of the separator provided at an end of the first electrode are located below the first electrode.

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