Nonaqueous electrolyte secondary battery, battery pack, and vehicle

Abstract

The invention provides a nonaqueous electrolyte secondary battery, a battery pack, and a vehicle. The housing (100) includes a housing main body (110) having a first opening (113) and a second opening (114) at both end portions in a first direction, respectively. The first electrode (210) is longer than the second electrode (240) in a second direction orthogonal to the first direction. The first electrode (210) and the second electrode (240) are alternately stacked in a third direction orthogonal to the first direction and the second direction. The diaphragm (800) has a multi-bend shape including a first bend section (810) and a second bend section (820) provided at the ends of the first electrode (210) and the second electrode (240), respectively, in the second direction. When the non-aqueous electrolyte secondary battery (1) is mounted in a vehicle such that the second direction faces the vertical direction, a first bent portion (810) of a separator (800) provided at an end of the first electrode in the second direction is positioned below the first electrode (210).

Description

Technical Field

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

[0002] The following secondary battery is disclosed in the specification of US Patent Application Publication No. 2022 / 0302533: a positive electrode terminal is provided at one end of a casing, and a negative electrode terminal is provided at the other end.

[0003] Japanese Patent Application Laid-Open No. 2012-190548 discloses that a separator interposed between a positive electrode plate and a negative electrode plate of a secondary battery is formed into a multi-fold shape. Summary of the invention

[0004] When the active material falls off from the electrode housed in the case, if the fallen active material reaches the opposite electrode, an internal short circuit may occur. In order to improve the reliability of the battery, it is desired to suppress this phenomenon.

[0005] The present technology aims to provide a highly reliable non-aqueous electrolyte secondary battery, and a battery pack and a vehicle including the same.

[0006] The present technology provides the following nonaqueous electrolyte secondary battery, battery pack, and vehicle.

[0007] [1] A nonaqueous electrolyte secondary battery installed in a vehicle, wherein the nonaqueous electrolyte secondary battery comprises: an electrode body having a first electrode and a second electrode stacked with a separator therebetween; an electrode terminal connected to the first electrode or the second electrode; and a casing for accommodating the electrode body and an electrolyte, the casing comprising: a casing body having a first opening at one end in a first direction and a second opening at another end in the first direction; a first sealing plate for sealing the first opening; and a second sealing plate for sealing the second opening, the electrode terminal being mounted on the first sealing plate and the second sealing plate. In either of the sealing plates, 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 stacked in a third direction orthogonal to the first direction and the second direction, the separator has a multi-bend shape including a first bend portion and a second bend portion respectively arranged at the ends of the first electrode and the second electrode in the second direction, and when the nonaqueous electrolyte secondary battery is mounted on the vehicle in a manner such that the second direction is directed in an up-down direction, the first bend portion of the separator arranged at the end of the first electrode is located below the first electrode.

[0008] [2] The nonaqueous electrolyte secondary battery according to [1], wherein the first electrode is a negative electrode.

[0009] [3] The nonaqueous electrolyte secondary battery according to [2], wherein the active material of the negative electrode includes carbon.

[0010] [4] A non-aqueous electrolyte secondary battery as described in [2] or [3], wherein the electrode body comprises: a main body; a negative electrode tab located on the first sealing plate side relative to the main body and provided on the first electrode; and a positive electrode tab located on the second sealing plate side relative to the main body and provided on the second electrode, the first electrode comprising: a negative electrode core; and a negative electrode active material layer formed on the negative electrode core, the second electrode comprising: a positive electrode core; a positive electrode active material layer formed on the positive electrode core; and a positive electrode protective layer formed on the positive electrode core, the positive electrode protective layer being located closer to the positive electrode tab side than the positive electrode active material layer, and in the main body of the electrode body, at an end portion on the positive electrode tab side, the positive electrode protective layer protrudes toward the positive electrode tab side relative to the end portion of the negative electrode active material layer.

[0011] [5] The nonaqueous electrolyte secondary battery according to any one of [1] to [4], wherein the nonaqueous electrolyte secondary battery is a lithium ion secondary battery.

[0012] [6] A non-aqueous electrolyte secondary battery as described in any one of [1] to [5], wherein the electrode terminal is arranged on one side relative to the center of the shell in the second direction, and the first bent portion is arranged on the side opposite to the electrode terminal relative to the center.

[0013] [7] A non-aqueous electrolyte secondary battery as described in any one of [1] to [6], wherein an injection hole for injecting the electrolyte into the shell is provided in the first sealing plate or the second sealing plate, the injection hole is arranged on one side relative to the center of the shell in the second direction, and the first bent portion is arranged on the same side as the injection hole relative to the center.

[0014] [8] The nonaqueous electrolyte secondary battery according to any one of [1] to [7], wherein

[0015] The shell body is provided with a discharge valve which ruptures preferentially when the pressure in the shell becomes above a specified value. The discharge valve is arranged on one side relative to the center of the shell in the second direction, and the first bending portion is arranged on the same side as the discharge valve relative to the center.

[0016] [9] A non-aqueous electrolyte secondary battery as described in any one of [1] to [8], wherein the shell body is formed into a square tube shape by joining the end edges of a plate-like member that has been subjected to a bending process to each other at a joining portion, the joining portion is arranged on one side relative to the center of the shell in the second direction, and the first bent portion is arranged on the side opposite to the joining portion relative to the center.

[0017]

[10] A battery pack comprising a plurality of non-aqueous electrolyte secondary batteries and mounted on a vehicle, wherein the plurality of non-aqueous electrolyte secondary batteries respectively comprise: an electrode body having a first electrode and a second electrode stacked with a separator therebetween; an electrode terminal connected to the first electrode or the second electrode; and a shell for accommodating the electrode body and an electrolyte, the shell comprising: a shell body having a first opening at one end in a first direction and a second opening at another end in the first direction; a first sealing plate for sealing the first opening; and a second sealing plate for sealing the second opening, the electrode terminal being mounted on the first sealing plate. The first electrode is longer than the second electrode in a second direction orthogonal to the first direction, the first electrode and the second electrode are alternately stacked in a third direction orthogonal to the first direction and the second direction, the diaphragm has a multi-bend shape including a first bend portion and a second bend portion respectively arranged at ends of the first electrode and the second electrode in the second direction, and when the battery pack is mounted on the vehicle in a manner such that the second direction is directed in an up-down direction, the first bend portion of the diaphragm arranged at the end of the first electrode is located below the first electrode.

[0018]

[11] A battery pack as described in

[10] , wherein the battery pack further comprises a bus bar connecting the electrode terminals of each of the plurality of non-aqueous electrolyte secondary batteries, the bus bar being arranged on one side relative to the center of the shell in the second direction, and the first bent portion being arranged on the side opposite to the bus bar relative to the center.

[0019]

[12] A vehicle, wherein the vehicle comprises: a vehicle body; and a battery pack including a plurality of non-aqueous electrolyte secondary batteries and mounted on the vehicle body, wherein the plurality of non-aqueous electrolyte secondary batteries respectively include: an electrode body in which a first electrode and a second electrode are stacked with a separator therebetween; an electrode terminal connected to the first electrode or the second electrode; and a casing for accommodating the electrode body and an electrolyte, the casing comprising: a casing body having a first opening at one end in a first direction and a second opening at another end in the first direction; a first sealing plate for sealing the first opening; and a second sealing plate for sealing the second opening, wherein the electrode terminals are arranged Installed on 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 stacked in a third direction orthogonal to the first direction and the second direction, the diaphragm has a multi-bend shape including a first bend portion and a second bend portion respectively arranged at the ends of the first electrode and the second electrode in the second direction, the battery pack is mounted on the vehicle body in a manner such that the second direction faces in an up-down direction, and the first bend portion of the diaphragm arranged at the end of the first electrode is located below the first electrode.

[0020] The foregoing and other objects, features, configurations and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a front view showing the structure of a secondary battery according to one embodiment.

[0022] Figure 2 It is shown when viewed from the direction of arrow II Figure 1 A diagram showing the state of a secondary battery.

[0023] Figure 3 It shows the direction of arrow III. Figure 1 A diagram showing the state of a secondary battery.

[0024] Figure 4 It is shown when viewed from the direction of arrow IV Figure 1 A diagram showing the state of a secondary battery.

[0025] Figure 5 It shows the direction of arrow V. Figure 1 A diagram showing the state of a secondary battery.

[0026] Figure 6 yes Figure 1 A front cross-sectional view of a secondary battery is shown.

[0027] Figure 7 It is a cross-sectional view of the negative plate.

[0028] Figure 8 It is a front view showing the negative electrode plate.

[0029] Fig. 9 It is a cross-sectional view of the positive plate.

[0030] Fig.10 It is a front view showing the positive electrode plate.

[0031] Fig.11 yes Figure 1 XI-XI cross-sectional view of the secondary battery shown.

[0032] Fig.12 yes Figure 1 A cross-sectional view taken along line XII-XII of the secondary battery shown.

[0033] Fig.13 1 is a flowchart showing a method for manufacturing a secondary battery according to one embodiment.

[0034] Fig.14 It is a perspective view showing a state before two electrode bodies included in a secondary battery according to an embodiment are overlapped.

[0035] Fig.15 yes Fig.14 The electrode body and the current collector are shown in a cross-sectional view taken along the line XV-XV.

[0036] Fig.16 It is a perspective view showing a state where a holder and a separator are attached to the electrode body.

[0037] Fig.17 It is a perspective view showing a state where a sealing plate is attached to the current collector on the negative electrode side.

[0038] Fig.18 yes Fig.17 XVIII-XVIII cross-sectional view of the electrode body and the current collector shown.

[0039] Fig.19 It is a perspective view showing a state where the electrode body is inserted into the case body.

[0040] Fig. 20 It is a perspective view showing a state where a sealing plate is attached to the current collector on the positive electrode side.

[0041] Fig.21 yes Fig. 20 XXI-XXI cross-sectional view of the electrode body and the current collector shown.

[0042] Fig. 22 It is a perspective view showing the structure of a secondary battery.

[0043] Fig.23 Schematic diagram showing the shape of a multi-fold diaphragm.

[0044] Fig.24 It is a schematic diagram showing the arrangement of separators in a secondary battery according to one embodiment.

[0045] Fig.25 It is a schematic diagram showing the arrangement of the separator in the secondary battery according to the comparative example.

[0046] Fig.26 is shown relative to Fig.24 Schematic diagram showing a state in which the liquid level of the residual liquid of the electrolyte is different (part 1).

[0047] Fig. 27 is shown relative to Fig.24 Schematic diagram of a state in which the liquid level of the residual liquid of the electrolyte is different in the state shown (second).

[0048] Fig.28 is shown relative to Fig.24 Schematic diagram showing different states of the residual electrolyte liquid level (part 3).

[0049] Fig.29 is shown relative to Fig.24 Schematic diagram of the state in which the liquid level of the residual liquid of the electrolyte is different (fourth).

[0050] Fig.30 is a schematic diagram showing the structure of an electrode body.

[0051] Fig.31 yes Fig.30 An enlarged view of part XXXI in FIG.

[0052] Fig.32 The figure shows a state where a battery pack including a plurality of secondary batteries is mounted on a vehicle.

[0053] Fig.33 It is a cross-sectional view showing the structure of a secondary battery according to a modification. DETAILED DESCRIPTION

[0054] 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.

[0055] In addition, in the embodiments described below, when the number, amount, etc. are mentioned, unless otherwise specified, the scope of the present technology is not necessarily limited to the number, amount, etc. In addition, in the following embodiments, each component is not an essential component for the present technology unless otherwise specified. In addition, the present technology is not limited to a configuration that necessarily exerts all the effects mentioned in the embodiments.

[0056] In addition, in this specification, the descriptions such as “comprise”, “include”, and “have” are not limiting. That is, when a certain structure is included, other structures other than the structure may be included or not.

[0057] In addition, in this specification, when geometrical terms and terms indicating position and direction relationships such as "parallel", "orthogonal", "oblique 45°", "coaxial", "along" and the like are used, these terms allow for manufacturing errors or slight variations. In this specification, when terms such as "upper side" and "lower side" are used to indicate relative positional relationships, these terms are used as terms indicating relative positional relationships in one state, and the relative positional relationships can be reversed or rotated to any angle depending on the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.).

[0058] In this specification, the term "secondary battery" is not limited to lithium-ion batteries, but may also include other secondary batteries such as nickel-hydrogen batteries and sodium-ion batteries. In this specification, the positive electrode and the negative electrode may be collectively referred to as "electrodes".

[0059] In addition, in the drawings, the long side direction of the stacked surface of the stacked electrode body of the secondary battery is set to the X direction. In addition, when viewed from the X direction, the short side direction of the electrode body is set to the Y direction, and when viewed from the X direction, the long side direction of the electrode body is set to the Z direction. In order to facilitate the understanding of the present technology, the dimensions of each component in the drawings are sometimes shown with some changes relative to the actual dimensions.

[0060] In the present application specification, the first direction (X direction) is sometimes referred to as the “width direction” of the secondary battery or the shell body, the second direction (Z direction) is similarly referred to as the “height direction” of the secondary battery or the shell body, and the third direction (Y direction) is similarly referred to as the “thickness direction” of the secondary battery or the shell body.

[0061] (Overall composition of the battery)

[0062] Figure 1 It is a front view of the secondary battery 1 which concerns on one embodiment. Figures 2 to 5 They are respectively shown as viewed from the direction of arrow II, arrow III, arrow IV, and arrow V. Figure 1 A diagram showing a state of a secondary battery 1 (non-aqueous electrolyte secondary battery) is shown. Figure 6 yes Figure 1 The secondary battery 1 is shown in front cross-sectional view.

[0063] The secondary battery 1 can be mounted on a battery electric vehicle (BEV), a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), etc. However, the use of the secondary battery 1 is not limited to vehicle-mounted use.

[0064] like Figures 1 to 6 As shown, 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 .

[0065] When forming a battery pack including secondary batteries 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 battery pack housing without using a constraining member.

[0066] The case body 110 is formed of a cylindrical (preferably a square cylindrical) member. Thus, a square secondary battery 1 can be obtained. The case body 110 is made of metal. Specifically, the case body 110 is formed of aluminum, aluminum alloy, iron, or iron alloy.

[0067] like Figure 1 , Figure 2 As shown in FIG. 1 , a sealing plate 120 (first wall) and a sealing plate 130 (second wall) are provided at both ends of the housing body. The housing body 110 can be formed by, for example, bringing the ends of the plate-like members that have been bent into contact with each other ( Figure 2 The illustrated joint portion 115) is joined to each other (for example, laser welding) to form a square tube shape. The corners of the "square tube shape" may also have an R angle (rounded corner) shape.

[0068] In the present embodiment, the shell body 110 is formed longer in the width direction (X direction) of the secondary battery 1 than in the thickness direction (Y direction) and the height direction (Z direction) of the secondary battery 1. The dimension (width) of the shell body 110 in the X direction is preferably about 30 cm or more. Thus, a relatively large (high capacity) secondary battery 1 can be formed. The dimension (height) of the shell body 110 in the Z direction is preferably about 20 cm or less, more preferably about 15 cm or less, and further preferably about 10 cm or less. Thus, a secondary battery 1 with a relatively low height (low height) can be formed, for example, the mountability on a vehicle is improved.

[0069] The shell 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 of the shell 100. The pair of second side portions 112 constitute the bottom portion and the top portion of the shell 100. The pair of first side portions 111 and the pair of second side portions 112 are respectively arranged in a mutually intersecting manner. The pair of first side portions 111 and the pair of second side portions 112 are connected at their respective ends. Preferably, the area of ​​each of the pair of first side portions 111 is larger than the area of ​​each of the pair of second side portions 112.

[0070] like Figure 5 As shown in FIG. 1 , a gas discharge valve 150 is provided on the second side surface 112B of one of the pair of second side surfaces 112. 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 from the center of the housing body 110 in the X direction to an extent that it does not reach both ends. The gas discharge valve 150 can be appropriately changed.

[0071] The thickness of the plate-shaped member at the gas discharge valve 150 is thinner than the thickness of the plate-shaped member of the housing body 110 other than the gas discharge valve 150. Therefore, when the pressure in the housing 100 becomes equal to or higher than a predetermined value, the gas discharge valve 150 breaks preferentially compared to other parts in the housing body 110, and the gas in the housing 100 is discharged to the outside.

[0072] like Figure 2 As shown, a joint portion 115 is formed on the other second side portion 112A 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 edges of the plate-like members constituting the case body 110 are joined to each other.

[0073] like Figure 3As shown in FIG. 1 , an opening 113 (first opening) is provided at the end of the first side in the first direction (X direction) of the housing body 110. The opening 113 is sealed by a sealing plate 120. A joint 115 is formed at the opening 113 to seal the opening 113. The opening 113 and the sealing plate 120 have a substantially rectangular shape with the Y direction being the short side direction and the Z direction being the long side direction. In addition, the substantially rectangular shape includes a substantially rectangular shape such as a rectangular shape or a substantially rectangular shape such as a shape in which the corners of the rectangular shape are rounded (rounded).

[0074] The sealing plate 120 (first sealing plate) is provided with a negative electrode terminal 301. The position of the negative electrode terminal 301 can be changed as appropriate.

[0075] like Figure 4 As shown in the figure, an opening 114 (second opening) is provided at the end of the second side opposite to the first side in the first direction (X direction) of the housing body 110. 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 the sealing plate 130. A joint 115 is formed at the opening 114 to seal the opening 114. The opening 114 and the sealing plate 130 have a substantially rectangular shape with the Y direction as the short side direction and the Z direction as the long side direction.

[0076] The sealing plate 130 (second sealing plate) is provided with a positive electrode terminal 302 and a liquid injection hole 160. The positions of the positive electrode terminal 302 and the liquid injection hole 160 can be changed as appropriate.

[0077] 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, aluminum alloy, iron, iron alloy, or the like.

[0078] 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 .

[0079] 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 .

[0080] The negative electrode terminal 301 may be made of a conductive material (more specifically, a metal), for example, copper or a copper alloy, etc. A portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface of the negative electrode terminal 301 .

[0081] 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.

[0082] The liquid injection hole 160 is sealed by a sealing member (not shown). As the sealing member, for example, a blind rivet or other metal member can be used.

[0083] The electrode body 200 is a flat electrode body in which positive plates and negative plates described later are stacked. Specifically, the electrode body 200 is a laminated electrode body in which a plurality of positive plates and a plurality of negative plates are alternately stacked via a separator 800 described later. The separator 800 can be composed of a microporous film made of polyolefin, for example. In the case where the electrode body is a laminated electrode body including a plurality of positive plates and a plurality of negative plates, the positive pole tabs provided on each positive plate can be stacked to form a positive pole tab group, and the negative pole tabs provided on each negative plate can be stacked to form a negative pole tab group. In addition, the electrode body 200 may also include a plurality of laminated electrode bodies.

[0084] like Figure 6 As shown in FIG. 1 , the housing 100 accommodates the electrode body 200. Figure 6 In FIG. 1 , a first electrode body 201 described later is illustrated. The first electrode body 201 is housed in the housing 100 so that the longitudinal direction thereof is parallel to the X direction.

[0085] Specifically, a single or a plurality of laminated electrode bodies are accommodated together with an electrolyte (electrolyte) not shown in the figure on the inner side of an insulating sheet 700 to be described later disposed in the housing 100. As the electrolyte (non-aqueous electrolyte), for example, the following electrolyte can be used: LiPF6 is dissolved at a concentration of 1.2 mol / L in a non-aqueous solvent obtained by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC) and dimethyl carbonate (DMC) in a volume ratio (25° C.) of 30:30:40.

[0086] The first electrode body 201 includes a substantially rectangular main body, a negative electrode tab group 220 (first electrode tab group), and a positive electrode tab group 250 (second electrode tab group).

[0087] The main body is composed of a negative electrode plate 210 and a positive electrode plate 240 described later. The negative electrode tab group 220 is located at an end of the first side of the first electrode body 201 in the first direction (X direction) relative to the main body. The first side in this embodiment is the sealing plate 120 side. The positive electrode tab group 250 is located at an end of the second side of the first electrode body 201 in the first direction (X direction) relative to the main body. The second side in this embodiment is the sealing plate 130 side.

[0088] 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.

[0089] 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 formed of a plate-like 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 .

[0090] The negative electrode current collector 400A is arranged on the sealing plate 120 via an insulating member made of resin. 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), for example, copper or a copper alloy. In addition, the details of the negative electrode current collector 400A will be described later.

[0091] The positive electrode collector 400B is arranged on the sealing plate 130 via an insulating member made of resin. The positive electrode collector 400B is electrically connected to the positive electrode tab group 250 and the positive terminal 302. The positive electrode collector 400B is composed of a conductive material (more specifically, a metal), for example, aluminum or an aluminum alloy. In addition, the positive electrode tab group 250 can also be electrically connected to the sealing plate 130 directly or via the positive electrode collector 400B. In this case, the sealing plate 130 can also play the role of the positive terminal 302. In addition, the details of the positive electrode collector 400B are described later.

[0092] (Configuration of Electrode Body 200)

[0093] Figure 7 is a cross-sectional view of the negative electrode plate 210 ( Figure 8 VII-VII section view in the figure), Figure 8 2 is a front view showing the negative electrode plate 210 .

[0094] like Figure 8 As shown, a negative electrode tab 230 (first electrode tab) composed of a negative electrode core 211 is provided at one end in the width direction of the negative electrode plate 210. When the negative electrode plates 210 are stacked, a plurality of negative electrode tabs 230 are stacked to form a negative electrode tab group 220. Considering the state of connection between the negative electrode tab group 220 and the negative electrode current collector 400A, the length of each of the negative electrode tabs 230 in the plurality of negative electrode plates 210 in the protruding direction is appropriately adjusted. In addition, the shape of the negative electrode tab 230 is not limited to Figure 7 The illustrated shape.

[0095] Fig. 9 is a cross-sectional view of the positive electrode plate 240 ( Fig.10 IX-IX section view in the figure), Fig.10 1 is a front view showing the positive electrode plate 240 .

[0096] like Fig.10As shown, at one end of the width direction of the formed positive electrode plate 240, a positive electrode tab 260 (second electrode tab) composed of a positive electrode core 241 is provided. When the positive electrode plates 240 are stacked, a plurality of positive electrode tabs 260 are stacked to form a positive electrode tab group 250. Considering the state of connection between the positive electrode tab group 250 and the positive electrode collector 400B, the length of the protruding direction of each positive electrode tab 260 in the plurality of positive electrode plates 240 can be appropriately adjusted. In addition, the shape of the positive electrode tab 260 is not limited to Fig.10 The illustrated shape.

[0097] The positive electrode protection layer 243 is provided at the root of the positive electrode tab 260. The positive electrode protection layer 243 does not necessarily need to be provided at the root of the positive electrode tab 260.

[0098] In a typical example, the thickness of the negative electrode tab 230 (one) is smaller than the thickness of the positive electrode tab 260 (one). In this case, the thickness of the negative electrode tab group 220 is smaller than the thickness of the positive electrode tab group 250.

[0099] (Connection Structure of Electrode Body 200 and Current Collector 400)

[0100] Fig.11 yes Figure 1 XI-XI cross-sectional view of the secondary battery shown in FIG. Fig.11 As shown, the electrode body 200 includes a first electrode body 201 and a second electrode body 202. The first electrode body 201 and the second electrode body 202 include a positive electrode (second electrode) and a negative electrode (first electrode), respectively. In addition, the electrode body 200 may be composed of three or more electrode bodies.

[0101] The electrode body 200 is formed by stacking a first electrode body 201 and a second electrode body 202. The first electrode body 201 and the second electrode body 202 are arranged in the thickness direction (Y direction) of the first electrode body 201 and the second electrode body 202.

[0102] 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 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 207 in the X direction.

[0103] The negative electrode tab group 220 has a bent portion 221 and a terminal portion 222. The bent portion 221 is a portion of the negative electrode tab group 220 bent on the side connected to the first electrode relative to the terminal portion 222. The terminal portion 222 is a portion of the negative electrode tab group 220 located at the end opposite to the side connected to the first electrode.

[0104] The negative electrode tab group 270 has a bent portion 271 and a terminal portion 272. The bent portion 271 is a portion of the negative electrode tab group 270 bent on the side connected to the first electrode relative to the terminal portion 272. The terminal portion 272 is a portion of the negative electrode tab group 270 located at the end opposite to the side connected to the first electrode.

[0105] The negative electrode tab group 220 and the negative electrode tab group 270 are bent in opposite directions so that the terminal portions 222 and 272 approach each other. In the present embodiment, the terminal portions 222 and 272 are separated, but the present invention is not limited to this configuration, and the terminal portions 222 and 272 may contact each other.

[0106] The negative electrode current collector 400A is electrically connected to the negative electrode terminal 301 and the negative electrode tab group 220 and the negative electrode tab group 270. The negative electrode current collector 400A in this embodiment is connected to the negative electrode terminal 301 between the electrode body 200 and the sealing plate 120.

[0107] The negative electrode current collector 400A includes a current collector 410 , a current collector 430 , and a current collector 440 .

[0108] The current collector 410 is a plate-shaped member. The current collector 410 has a long side 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 long side 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 side by side in the X direction. In this way, the current collector 410 and the current collector 430 are composed of separate components.

[0109] 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, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. 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, for example, by ultrasonic welding.

[0110] The current collector 440 is joined to the current collector 410 and the current collector 430 at a joint portion (not shown) located at an 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 caulking and / or welding, for example.

[0111] The negative electrode terminal 301 is exposed to the outside of 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.

[0112] 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 for the purpose of ensuring a connection area with a bus bar that electrically connects the secondary battery 1 to other adjacent secondary batteries. The connection between the negative terminal 301 and the plate-shaped member 303 can be formed by, for example, laser welding.

[0113] An insulating member 510 is disposed between the plate-shaped 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 .

[0114] However, the negative electrode terminal 301 may be electrically connected to the sealing plate 120 . In addition, the sealing plate 120 may also play the role of the negative electrode terminal 301 .

[0115] A separator 600 is disposed between the sealing plate 120 and the main body of the electrode body 200 (excluding the negative electrode tab group 220). The separator 600 is composed of an insulating resin member. The separator 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 the engaging portions (not shown) at both ends in the Z direction.

[0116] The end portions of the first member 610 and the second member 620 on the electrode body 200 side in the X direction protrude in the Y direction. Thus, the separator 600 plays a guiding role when the bent portions 221 and 271 are bent, and the bent portions 221 and 271 are easily bent.

[0117] An insulating sheet 700 (electrode body support) made of resin is disposed between the electrode body 200 and the case body 110. The insulating sheet 700 may be made of, for example, resin. More specifically, the insulating sheet 700 may be made of, for example, polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyimide (PI), or polyolefin (PO).

[0118] Fig.12 yes Figure 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 this embodiment is different from that on the negative electrode side in that the portion corresponding to the current collector 410 and the current collector 430 on the negative electrode side is composed of one member (current collector 420).

[0119] 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 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 208 in the X direction.

[0120] The positive electrode tab group 250 has a bent portion 251 and a terminal portion 252. The bent portion 251 is a portion of the positive electrode tab group 250 bent on the side connected to the second electrode relative to the terminal portion 252. The terminal portion 252 is a portion of the positive electrode tab group 250 located at the end opposite to the side connected to the second electrode.

[0121] The positive electrode tab group 280 has a bent portion 281 and a terminal portion 282. The bent portion 281 is a portion of the positive electrode tab group 280 bent on the side connected to the second electrode relative to the terminal portion 282. The terminal portion 282 is a portion of the positive electrode tab group 280 located at the end opposite to the side connected to the second electrode.

[0122] The positive electrode tab group 250 and the positive electrode tab group 280 are bent in opposite directions so that the terminal portions 252 and 282 approach each other. In addition, in this embodiment, the terminal portions 252 and 272 are separated, but the present invention is not limited to this structure, and the terminal portions 252 and 282 may also contact each other.

[0123] 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 this embodiment is connected to the positive electrode terminal 302 between the electrode body 200 and the sealing plate 130.

[0124] The positive electrode current collector 400B includes a current collector 420 and a current collector 450 .

[0125] The current collector 420 is a plate-shaped member. The current collector 420 has a long side direction in the Z direction and a short side direction in the Y direction. The current collector 420 is composed of a single integral component.

[0126] The positive electrode tab group 250 and the positive electrode tab group 280 are joined to the collector 420 composed of one component at a joining portion 421 described later. The joining portion 421 can be formed, for example, by ultrasonic welding, resistance welding, laser welding, riveting, etc. In the present embodiment, the positive electrode tab group 250 and the positive electrode tab group 280 and the collector 420 are joined, for example, by ultrasonic joining.

[0127] The current collector 450 is joined to the current collector 420 at a joint portion (not shown) located at an 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 caulking and / or welding, for example.

[0128] The positive electrode terminal 302 is exposed to the outside of the sealing plate 130 and is provided so as to 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 .

[0129] 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 for the purpose of ensuring a connection area with a bus bar that electrically connects the secondary battery 1 to other adjacent secondary batteries. The connection between the positive terminal 302 and the plate-shaped member 304 can be formed by laser welding, for example.

[0130] An insulating member 510 is disposed between the plate-shaped member 304 and the sealing plate 130 . An insulating member 520 is disposed between the positive electrode terminal 302 and the sealing plate 130 . An insulating member 530 is disposed between the current collector 450 and the sealing plate 130 .

[0131] However, the positive electrode terminal 302 may be electrically connected to the sealing plate 130 . In addition, the sealing plate 130 may also play the role of the positive electrode terminal 302 .

[0132] A separator 600 is arranged between the sealing plate 130 and the main body of the electrode body 200 (excluding the positive electrode tab group 250, 280). The separator 600 is composed of an insulating resin member. The separator 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 the engaging portions (not shown) at both ends in the Z direction.

[0133] The end portions of the first member 610 and the second member 620 on the electrode body 200 side in the X direction protrude in the Y direction. Thus, the separator 600 plays a guiding role when the bent portions 251 and 281 are bent, and the bent portions 251 and 281 are easily bent.

[0134] An insulating sheet 700 (electrode body holder) made of resin is arranged between the electrode body 200 and the case body 110 .

[0135] (Manufacturing process of secondary battery 1)

[0136] Hereinafter, a method for manufacturing the secondary battery according to the present embodiment will be described. Fig.13 1 is a flowchart showing a method for manufacturing a secondary battery according to the present embodiment. Fig.14 It is a perspective view showing a state before two electrode bodies according to the secondary battery according to the present embodiment are stacked. Fig.15 yes Fig.14 The electrode body and the current collector are shown in a cross-sectional view taken along the line XV-XV.

[0137] like Fig.13 As shown, in the manufacturing method of the secondary battery according to the present embodiment, first, the first electrode body 201 and the second electrode body 202 are manufactured (step S1). The negative electrode tab group 220, the positive electrode tab group 250, the negative electrode tab group 270, and the positive electrode tab group 280 are respectively cut off part of the ends so that the lengths of the ends become the same when they are tied.

[0138] like Figure 13~Figure 15 As shown, after the first electrode body 201 and the second electrode body 202 are manufactured, the negative electrode tab group 220 is joined to the current collector 410 (step S2). The negative electrode tab group 220 is joined to the current collector 410 at the joining portion 411. Next, the negative electrode tab group 270 is joined to the current collector 430 (step S3). The negative electrode tab group 270 is joined to the current collector 430 at the joining portion 431.

[0139] Next, the first electrode body 201, the current collector 420, and the second electrode body 202 are arranged in the first direction (DR1 direction) in sequence. The positive electrode tab group 250 is arranged on one side of the current collector 420 in the first direction (DR1 direction). In a state where the positive electrode tab group 280 is arranged on the other side of the current collector 420 in the first direction (DR1 direction), the positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 (S4 process). The positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420 at the joining portion 421.

[0140] 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 on one side relative to the center of the first electrode body 201 and the second electrode body 202. This allows the current collectors to be short and compact.

[0141] In addition, the current collector 410, the current collector 420, and the current collector 430 are not limited to this configuration. The current collector 410, the current collector 420, and the current collector 430 may be arranged at the center 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, the negative electrode tab group 220, the positive electrode tab group 250, the negative electrode tab group 270, and the positive electrode tab group 280 are arranged at the center of the first electrode body 201 and the second electrode body 202, respectively, corresponding to the current collector 410, the current collector 420, and the current collector 430.

[0142] In addition, the order of the steps of joining the collector 410, the collector 420, and the collector 430 to the first electrode body 201 and the second electrode body 202, respectively, is not limited to the above content, and the order may be changed. The steps of joining the collector 410 and the collector 430 to the first electrode body 201 and the second electrode body 202, respectively, are preferably performed before the step of overlapping the first electrode body 201 and the second electrode body 202 described later, and are preferably performed before the step of joining the collector 420 to the first electrode body 201 and the second electrode body 202.

[0143] Next, after the positive electrode tab group 250 and the positive electrode tab group 280 are joined to the current collector 420, the first electrode body 201 and the second electrode body 202 are connected in the thickness direction (with respect to the positive electrode tab group 250 and the positive electrode tab group 280). Fig.14 as well as Fig.15 The positive electrode tab group 250 and the positive electrode tab group 280 are bent in a direction perpendicular to the DR1 direction of the electrode 200 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 brought together.

[0144] The so-called “overlapping the first electrode body and the second electrode body” may be directly overlapping the first electrode body and the second electrode body, or other components may be arranged between the first electrode body and the second electrode body. In addition, the first electrode body and the second electrode body may be fixed by a belt or the like, or may not be fixed. Furthermore, the first electrode body, the current collector, and the second electrode body may not be arranged on a straight line in the first direction (DR1 direction), or the first electrode body or the second electrode body may be inclined relative to the first direction (DR1 direction) with respect to the current collector.

[0145] The positive electrode tab group 250 and the positive electrode tab group 280 are bent so that their end portions face each other. In addition, the negative electrode tab group 220 and the negative electrode tab group 270 are also bent so that their end portions face each other.

[0146] Fig.13 as well as Fig.162 is a perspective view showing a state where a bracket and a separator are installed on an electrode body. Fig.16 As shown, next, the separator 600 and the insulating sheet 700 are assembled on the electrode body 200 (step S6 ).

[0147] In addition, the insulating sheet 700 does not necessarily have to cover the entire surface of the electrode body 200. The insulating sheet 700 preferably covers about 50% or more of the outer surface of the electrode body, and more preferably covers about 70% or more of the area. The insulating sheet 700 preferably covers the entirety of four of the six surfaces of the substantially rectangular parallelepiped (flat) electrode body 200 except for at least two surfaces on which the negative electrode tab group 220 and the positive electrode tab group 250 are formed.

[0148] Fig.17 It is a perspective view showing a state where the sealing plate 120 is attached to the current collector on the negative electrode side. Fig.18 yes Fig.17 XVIII-XVIII cross-sectional view of the electrode body and the current collector shown.

[0149] like Fig.13 , Fig.17 as well as Fig.18 As shown, after the negative electrode tab group 220 is joined to the current collector 410, the negative electrode tab group 270 is joined to the current collector 430, and the first electrode body 201 and the second electrode body 202 are overlapped, 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). Alternatively, step S7 may be performed before step S6.

[0150] Specifically, the negative electrode tab group 220 and the negative electrode tab group 270 are bent so that the terminal ends 222 and 272 face each other.

[0151] The negative terminal 301 and the current collector 440 are mounted on the sealing plate 120 via an insulating member. The current collector 440 is brought into contact with the current collector 410 and the current collector 430 in the X direction. In addition, the plate-like member 303 may be connected to the negative terminal 301 at any time. The current collector 440 is joined to the current collector 410 and the current collector 430 by laser welding between the sealing plate 120 and the insulating sheet 700.

[0152] Fig.19 2 is a perspective view showing a state where the electrode body is inserted into the housing body. Fig.13 as well as Fig.19 As shown, after the first electrode body 201 and the second electrode body 202 are stacked, 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 ).

[0153] The negative electrode tab group 220 and the negative electrode tab group 270 are bent by bringing the sealing plate 120 and the main body of the electrode body 200 (the first electrode body 201 and the second electrode body 202) close to each other. In addition, it is preferable that the sealing plate 120 and the case body 110 are brought close to each other by bringing the sealing plate 120 and the main body of the electrode body 200 disposed in the case body 110 close to each other. Fig.11 As shown, the negative electrode tab group 220 and the negative electrode tab group 270 are bent along the shape of the separator 600 so that the folded-back portions of the bent portions 221 and 271 approach the case body 110 in the Y direction.

[0154] After the sealing plate 120 is brought into contact with the housing body 110, the sealing plate 120 is temporarily joined to the housing body 110. By temporarily joining, the sealing plate 120 is partially joined to the opening 113 of the housing body 110. Thus, the sealing plate 120 is positioned relative to the housing body 110.

[0155] When the electrode body 200 is inserted into the case body 110, the electrode body 200 may be pulled from the current collector 420 side or pressed from the current collectors 410 and 430 sides. When the electrode body 200 is pressed from the current collectors 410 and 430 sides, the negative electrode tab group 220 and the negative electrode tab group 270 can be bent simultaneously.

[0156] Fig. 20 It is a perspective view showing a state where a sealing plate 130 is attached to the current collector on the positive electrode side. Fig.21 yes Fig. 20 The electrode body and the collector are shown in the XXI-XXI cross-sectional view. Fig.21 In the embodiment, the shell body 110 is omitted.

[0157] like Fig.13 , Fig. 20 as well as Fig.21 As shown, after the first electrode body 201 and the second electrode body 202 are inserted into the case body 110 , the current collector 420 and the positive electrode terminal 302 are electrically connected (step S9 ).

[0158] Specifically, the positive terminal 302 and the current collector 450 are mounted on the sealing plate 130 via an insulating member. After the first electrode body 201 and the second electrode body 202 are inserted into the case body 110, the current collector 450 is brought into contact with the current collector 420 protruding from the opening 114 in the X direction. In addition, the plate-like member 304 may be connected to the positive terminal 302 at any time.

[0159] like Fig.21As shown, the positive electrode tab group 250 and the positive electrode tab group 280 connected to the current collector 420 are bent so that the end portions 252 and 282 face each other. Fig.21 From the state shown, the sealing plate 130 is brought into contact with the case body 110. At this time, the positive electrode tab group 250 and the positive electrode tab group 280 are bent by bringing the sealing plate 130 and the main body of the electrode body 200 close to each other. Fig.12 As shown, the positive electrode tab group 250 and the positive electrode tab group 280 are bent along the shape of the separator 600 so that the folded-back portions of the bent portions 251 and 281 approach the case body 110 in the Y direction.

[0160] After the sealing plate 130 is brought into contact with the housing body 110, the sealing plate 130 is temporarily welded to the housing body 110. By temporarily joining, the sealing plate 130 is partially joined to the opening 114 of the housing body 110. Thus, the sealing plate 130 is positioned relative to the housing body 110.

[0161] Fig. 22 1 is a perspective view showing the structure of the secondary battery 1. Fig.13 as well as Fig. 22 As shown, 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. Thus, the first electrode body 201 and the second electrode body 202 are accommodated in the case 100.

[0162] After the above-mentioned process, a leakage check and other inspections are performed (S11 process). After the leakage check, the secondary battery 1 is dried to remove the moisture in the shell 100. And, the electrolyte is injected into the inside of the shell 100 from the injection hole 160. When injecting the electrolyte, the sealing plate 130 is facing upward, the sealing plate 120 is facing downward, the shell 100 is tilted, and the electrolyte is injected into the inside of the shell 100 from the injection hole 160 of the sealing plate 130. Then, exhaust charging is performed. During exhaust charging, the injection hole 160 can also be temporarily sealed. Then, the injection hole 160 is sealed, and the secondary battery 1 is completed.

[0163] In addition, the order of the insertion process of the electrode body 200 and the connection process of the current collectors is not limited to the above example. For example, only a part of the electrode body 200 can be inserted into the case body 110 in a manner such that the end of the opening 113 side of the negative electrode active material layer 212 is arranged outside the case body 110 (first process), and then the negative terminal 301 (first electrode terminal) provided on the sealing plate 120 (first sealing plate) and the negative electrode tab group 220, 270 (first electrode tab) are electrically connected, and then the electrode body 200 is inserted into the case body 110 until the end of the opening 113 side of the negative electrode active material layer 212 is arranged inside the case body 110 (second process). That is, the negative terminal 301 and the electrode body 200 can be electrically connected in the middle of the insertion process of the electrode body 200 into the case body 110.

[0164] In this embodiment, by providing the negative electrode tab group 220 and the positive electrode tab group 250 in the first electrode body 201 and providing the negative electrode tab group 270 and the positive electrode tab group 280 in the second electrode body 202, it is possible to have separate electrode tabs in the first electrode body 201 and the second electrode body 202. According to this structure, the electrode tabs gathered together are formed by the first electrode body 201 and the second electrode body 202, and the electrode tabs can be shortened compared to the case where the electrode tabs are bent. As a result, the volume occupied by the electrode tabs can be reduced, and thus the energy density of the secondary battery 1 can be improved. In addition, in the structure in which separate electrode tabs are provided in the first electrode body 201 and the second electrode body 202, the electrode tabs are easy to bend compared to the case in which the electrode tabs are gathered together by the first electrode body 201 and the second electrode body 202, so that the electrode tabs are easy to be joined to the collector, and the secondary battery can be stably manufactured. In particular, since the secondary battery 1 can be manufactured stably, the reliability of the connection portion between the electrode tab and the current collector can be improved.

[0165] (Shape and Configuration of Diaphragm 800)

[0166] Fig.23 2 is a schematic diagram showing the shapes of the negative electrode plate 210 , the positive electrode plate 240 , and the separator 800 .

[0167] like Fig.23 As shown, the negative electrode plate 210 (first electrode) is formed longer than the positive electrode plate 240 (second electrode) in the Z direction (second direction). The negative electrode plates 210 and the positive electrode plates 240 are alternately stacked in the Y direction (third direction).

[0168] The separator 800 has a multi-bend shape including a plurality of bends 810 and 820. The bend 810 is provided at an end of the negative electrode plate 210 in the Z direction, and the bend 820 is provided at an end of the positive electrode plate 240 in the Z direction. Fig.23 The shape of the substantially U-shaped bending portions 810 and 820 (turned portions) shown is an example, and the scope of the present technology is not limited thereto. Fig.24 The shapes of the bent portions 810 and 820 (turned portions) are substantially V-shaped as shown.

[0169] Fig.24 Schematic diagram showing the arrangement of the separator 800 in the secondary battery 1 according to the present embodiment. Fig.25 1 is a schematic diagram showing the arrangement of a separator 800A in a secondary battery 1A according to a comparative example.

[0170] The secondary batteries 1 and 1A are both mounted on the vehicle with the Z direction facing the up-down direction (approximately the vertical direction), more specifically, with the +Z side facing the upper side. Fig.24 In the secondary battery 1 shown in FIG. 1 , the bend 810 (first bend) is located below the negative electrode plate 210 (first electrode), and the bend 820 (second bend) is located above the positive electrode plate 240 (second electrode). Fig.25 In the secondary battery 1A shown, 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 .

[0171] 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 easily detached from the negative electrode active material layer 212 of the negative electrode plate 210. In addition, generally speaking, the bonding force of the negative electrode active material layer 212 to the negative electrode core 211 is weaker than the bonding force 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 easily peeled off.

[0172] The negative electrode active material layer 212 may contain a binder (SBR, CMC, etc.) and a conductive member (carbon material, etc.) in addition to the negative electrode active material. As the negative electrode active material, carbon materials such as graphite, silicon materials such as SiO, SiC, etc. may be used. The negative electrode active material may also be a mixture of multiple materials.

[0173] like Fig.24 , Fig.25 As shown, the residual liquid of the electrolyte 200A accumulates at the bottom of the case 100. When the negative electrode active material layer 212 is immersed in the residual liquid of the electrolyte 200A, the active material tends to be more easily peeled off.

[0174] If the conductive active material peeled off from the electrode plate floats in the electrolyte 200A and moves to the opposite electrode, self-discharge or short circuit may occur inside the case 100 .

[0175] In contrast, in the secondary battery 1 ( Fig.24 ), the bent portion 810 of the separator 800 is arranged below the negative electrode plate 210 from which the active material is more likely to fall off. Therefore, compared with the secondary battery 1A ( Fig.25 ), the active material falling 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 can be provided in which self-discharge and short circuit failure are suppressed.

[0176] (Liquid level of the remaining electrolyte 200A)

[0177] Figure 26 to Figure 29 is shown relative to Fig.24 The state shown is a schematic diagram of a state in which the liquid level height of the residual liquid of the electrolyte solution 200A is different.

[0178] Fig.26 2 shows a state after the electrode body 200 is housed in the case 100 and before the electrolyte 200A is injected. Fig. 27 2 shows the state immediately after the electrolyte 200A is injected into the housing 100. Fig.28 The electrode body 200 is shown to be impregnated with the injected electrolyte 200A. Fig.29 The state of charging or discharging the secondary battery 1 is shown.

[0179] like Fig.24 as well as Figure 26 to Figure 29 As shown in FIG. 1 , the liquid level of the residual liquid of the electrolyte 200A varies in each state. However, in the use state of the secondary battery 1 ( Fig.24 , Figure 27 to Figure 29 ), the electrolyte 200A accumulated under the negative electrode plate 210 is in a state of being sandwiched by the multi-fold separator 800. Therefore, even if the negative electrode active material detached from the negative electrode plate 210 floats in the electrolyte 200A, it can be suppressed from reaching the positive electrode plate 240 as the opposite pole. In this way, a highly reliable secondary battery 1 can be provided.

[0180] (Structure of End Part of Electrode Body 200)

[0181] Fig.30 is a schematic diagram showing the structure of the electrode body 200, Fig.31 yes Fig.30 An enlarged view of part XXXI in FIG.

[0182] like Fig.30 , Fig.31 As shown, in the main body of the electrode body 200, at the end of the positive electrode tab group 250, 280 side, the positive electrode protection layer 243 protrudes toward the positive electrode tab group 250, 280 side compared to the end of the negative electrode active material layer 212. The positive electrode protection layer 243 protrudes toward the positive electrode tab group 250, 280 side (+X side) compared to the end of the negative electrode active material layer 212 by a distance G1.

[0183] Here, the positive electrode protection layer 243 protrudes in the X direction (first direction) connecting the opening 113 and the opening 114 compared to the end of the negative electrode active material layer 212. The positive electrode protection layer 243 protrudes in the insertion direction of the electrode body 200 compared to the end of the negative electrode active material layer 212. The positive electrode protection layer 243 protrudes in the direction perpendicular to the sealing plates 120 and 130 compared to the end of the negative electrode active material layer 212.

[0184] Therefore, when the electrode body 200 is inserted into the case body 110, even if a certain load is applied near the end of the negative electrode active material layer 212 located in the +X direction, such as a load that causes the electrode body 200 to move in the case body 110 due to vibration, damage to the end of the negative electrode active material layer 212 can be suppressed, and the negative electrode active material can be suppressed from falling off. As a result, the reliability of the secondary battery 1 can be further improved.

[0185] In the laminated electrode body, the negative electrode active material is likely to fall off when the electrode body 200 is inserted into the case body 110. Fig.30 , Fig.31 The structure shown can achieve a significant effect in suppressing damage to the end portion of the negative electrode active material layer 212 .

[0186] (Structure for mounting on vehicles)

[0187] Fig.32 1 is a diagram showing a state where a battery pack including a plurality of secondary batteries 1 is mounted on a vehicle. Fig.32 As shown, a plurality of secondary batteries 1 are arranged (stacked) along the Y direction and mounted on the vehicle body 1000 in a state restrained in the Y direction by restraint bars 2. Alternatively, the restraint bars 2 may not be used, and the secondary batteries 1 may be directly supported by a battery pack case (not shown).

[0188] A bus bar 3 is provided for electrically connecting the electrode terminals 300 of the adjacent secondary batteries 1 .

[0189] When the secondary battery 1 is regarded as a single unit, or when a plurality of secondary batteries 1 are regarded as a battery pack, the upper side and the lower side in the state of being mounted on the vehicle body 1000 can be determined, for example, as follows.

[0190] The secondary battery 1 according to the present embodiment is mounted on the vehicle body 1000 such that the +Z side is directed upward.

[0191] like Fig.32 As shown, the electrode terminal 300 and the bus bar 3 are arranged on the upper side (+Z side) relative to the center (center line O) of the housing 100 in the Z direction. The injection hole 160 is arranged on the lower side (-Z side) relative to the center line O. The gas discharge valve 150 is arranged on the lower side (-Z side) relative to the center line O. The joint 115 of the housing body 110 is arranged on the upper side (+Z side) relative to the center line O.

[0192] On the other hand, the bent portion 810 located below the negative electrode plate 210 is arranged on the lower side (−Z side) with respect to the center line O of the case 100 .

[0193] That is, in Fig.32 In the example shown, the bent portion 810 located below the negative electrode plate 210 is arranged on the side opposite to the electrode terminal 300 and the bus bar 3 relative to the center line O of the shell 100, and is arranged on the same side as the injection hole 160 relative to the center line O, and is arranged on the same side as the gas discharge valve 150 relative to the center line O, and is arranged on the side opposite to the joint 115 relative to the center line O.

[0194] However, the above-mentioned positional relationship is a relative relationship that varies depending on the arrangement of the electrode terminal 300 or the bus bar 3 , the liquid injection hole 160 , the gas discharge valve 150 , and the joint 115 .

[0195] (Modification of Secondary Battery 1)

[0196] Fig.33 2 is a cross-sectional view showing the structure of a secondary battery according to a modified example. Fig.33 As shown, in the secondary battery according to the modification, the negative electrode tab group 220 and the negative electrode tab group 270 have their terminal ends 222 and 272 bent in the same direction in the Y direction.

[0197] Then, 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, the negative electrode tab group 220 and the negative electrode tab group 270 are bent in the same direction so that the end portions 222 and 272 face the same direction. In order to facilitate bending of the end portions 222 and 272 in the same direction, the third component 630 of the separator 600 is provided between the negative electrode tab group 220 and the negative electrode tab group 270.

[0198] By forming the negative electrode tab group 220 and the terminal portions 222 and 272 of the negative electrode tab group 270 to be bent in the same direction in the Y direction, the first electrode body 201 on which the current collector 410 is mounted and the second electrode body 202 on which the current collector 430 is mounted can be prepared with the same structure. Thus, the first electrode body 201 on which the current collector 410 is mounted and the second electrode body 202 on which the current collector 430 is mounted can be configured as one type, thereby simplifying the manufacturing process.

[0199] In addition, in this embodiment, an example is described in which the negative terminal 301 is provided on the sealing plate 120 and the positive terminal 302 is provided on the sealing plate 130, but the scope of the present technology is not limited to this. For example, electrode terminals 300 of both poles may be provided on one sealing plate.

[0200] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A non-aqueous electrolyte secondary battery, the non-aqueous electrolyte secondary battery being mounted on a vehicle, wherein: The non-aqueous electrolyte secondary battery comprises: an electrode body having a first electrode and a second electrode stacked with a separator therebetween; an electrode terminal connected to the first electrode or the second electrode; and a shell for accommodating the electrode body and the electrolyte, The housing includes: a housing body having a first opening at one end in a first direction and a second opening at another 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 mounted on 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 stacked in a third direction orthogonal to the first direction and the second direction. The diaphragm has a multi-bend shape including a first bend portion and a second bend portion provided at ends of the first electrode and the second electrode respectively in the second direction, When the nonaqueous electrolyte secondary battery is mounted on the vehicle with the second direction oriented in the up-down direction, the first bent portion of the separator provided at the end of the first electrode is located below the first electrode.

2. The nonaqueous electrolyte secondary battery according to claim 1, wherein The first electrode is a negative electrode.

3. The nonaqueous electrolyte secondary battery according to claim 2, wherein: The active material of the negative electrode includes carbon.

4. The nonaqueous electrolyte secondary battery according to claim 2 or 3, wherein: The electrode body comprises: a main body; a negative electrode tab located on the first sealing plate side relative to the main body and provided on the first electrode; and a positive electrode tab located on the second sealing plate side relative to the main body and provided on the second electrode. The first electrode comprises: a negative electrode core; and a negative electrode active material layer formed on the negative electrode core. The second electrode comprises: a positive electrode core; a positive electrode active material layer formed on the positive electrode core; and a positive electrode protective layer formed on the positive electrode core. The positive electrode protection layer is located closer to the positive electrode tab than the positive electrode active material layer. In the main body portion of the electrode body, at an end portion on the positive electrode tab side, the positive electrode protection layer protrudes toward the positive electrode tab side relative to an end portion of the negative electrode active material layer.

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

6. The nonaqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein The electrode terminal is arranged on one side relative to the center of the housing in the second direction. The first bent portion is arranged on the side opposite to the electrode terminal with respect to the center.

7. The nonaqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein The first sealing plate or the second sealing plate is provided with a liquid injection hole for injecting the electrolyte into the housing. The liquid injection hole is arranged on one side relative to the center of the housing in the second direction. The first bent portion is arranged on the same side as the liquid injection hole with respect to the center.

8. The nonaqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein The housing body is provided with a discharge valve which is preferentially ruptured when the pressure in the housing becomes equal to or higher than a predetermined value. The discharge valve is arranged on one side relative to the center of the housing in the second direction. The first bent portion is arranged on the same side as the discharge valve with respect to the center.

9. The nonaqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein The housing body is formed into a square tube shape by joining the end sides of a plate-like member subjected to bending processing to each other at a joining portion. The joining portion is arranged on one side relative to the center of the housing in the second direction. The first bent portion is arranged on the side opposite to the joining portion with respect to the center.

10. A battery pack comprising a plurality of non-aqueous electrolyte secondary batteries and mounted on a vehicle, wherein: The plurality of non-aqueous electrolyte secondary batteries respectively include: an electrode body having a first electrode and a second electrode stacked with a separator therebetween; an electrode terminal connected to the first electrode or the second electrode; and a shell for accommodating the electrode body and the electrolyte, The housing includes: a housing body having a first opening at one end in a first direction and a second opening at another 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 mounted on 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 stacked in a third direction orthogonal to the first direction and the second direction. The diaphragm has a multi-bend shape including a first bend portion and a second bend portion provided at ends of the first electrode and the second electrode respectively in the second direction, When the battery pack is mounted on the vehicle with the second direction oriented in the up-down direction, the first bent portion of the separator provided at the end of the first electrode is located below the first electrode.

11. The battery pack according to claim 10, wherein: The battery pack further includes a bus bar connecting the electrode terminals of the plurality of non-aqueous electrolyte secondary batteries. The bus bar is arranged on one side relative to the center of the housing in the second direction. The first bent portion is arranged on the side opposite to the bus bar with respect to the center.

12. A vehicle, wherein: The above-mentioned vehicles shall have: body; and A battery pack including a plurality of non-aqueous electrolyte secondary batteries and mounted on the vehicle body, The plurality of non-aqueous electrolyte secondary batteries respectively include: an electrode body having a first electrode and a second electrode stacked with a separator therebetween; an electrode terminal connected to the first electrode or the second electrode; and a shell for accommodating the electrode body and the electrolyte, The housing includes: a housing body having a first opening at one end in a first direction and a second opening at another 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 mounted on 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 stacked in a third direction orthogonal to the first direction and the second direction. The diaphragm has a multi-bend shape including a first bend portion and a second bend portion provided at ends of the first electrode and the second electrode respectively in the second direction, The battery pack is mounted on the vehicle body with the second direction facing the up-down direction, and the first bent portion of the separator provided at the end of the first electrode is located below the first electrode.

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