Secondary battery and battery pack

Abstract

The present application relates to a secondary battery and a battery pack. A first face (111A) of an outer can (100) has a substantially rectangular shape including a pair of first end edges (101) extending in a first direction and a pair of second end edges (102) extending in a second direction substantially orthogonal to the first direction. An insulating member (600) has a first region (610) disposed in the vicinity of at least one of the pair of first end edges (101), extending in a band shape in the first direction, and a second region (620) located in the second direction at a position closer to a central side of the insulating member (600) than the first region (610). The thickness of the insulating member (600) in the first region (610) is greater than the thickness of the insulating member (600) in the second region (620).

Description

Technical Field

[0001] This technology relates to secondary batteries and battery packs. Background Technology

[0002] Japanese Patent Application Publication No. 2021-177471 discloses a square battery in which a sheet-shaped insulating member is inserted into the battery casing along with the electrode body in a bent state along the surface of the electrode body. Summary of the Invention

[0003] The requirement is to suppress metal deposition in secondary batteries. When a battery pack is constructed from secondary batteries in a square-shaped outer can, the pressure load tends to be relatively small near the end edges of the roughly rectangular outer can. This deviation in pressure load creates a resistance difference within the electrode body, easily leading to metal deposition. Therefore, it is necessary to effectively suppress metal deposition in areas with relatively small pressure loads. From this perspective, there is still room for improvement in conventional secondary batteries.

[0004] The purpose of this technology is to provide a secondary battery with suppressed metal deposition and a battery pack having the secondary battery.

[0005] This technology provides the following secondary batteries and battery packs.

[0006] [1] A secondary battery, comprising: an electrode body including a main body and electrode tabs; an insulating member disposed on the outside of the electrode body; and an outer can having a square shape for housing the electrode body and the insulating member, the outer can having a pair of first surfaces, a pair of second surfaces substantially orthogonal to the first surfaces, and a pair of third surfaces substantially orthogonal to the first and second surfaces, the area of ​​the first surface being larger than the area of ​​the second surface and the area of ​​the third surface, the first surface having a pair of first end edges extending along a first direction and a pair of first end edges extending along a first direction. The insulating member has a generally rectangular shape including a pair of second end edges extending in an orthogonal second direction. It has a first region and a second region. The first region is located near at least one of the pair of first end edges and extends in a strip shape along the first direction. The second region is located in the second direction closer to the center of the insulating member than the first region. The first region and the second region are arranged to overlap the main body of the electrode body in a third direction orthogonal to the first direction and the second direction. The thickness of the insulating member in the first region is greater than the thickness of the insulating member in the second region.

[0007] [2] According to the secondary battery of [1], the first region is disposed near both of the pair of first end edges.

[0008] [3] According to the secondary battery of [1] or [2], wherein the first region is provided throughout the entire length of the main body of the electrode body in the first direction.

[0009] [4] The secondary battery according to any one of [1] to [3], wherein, in the first region, the sheet constituting the insulating member is multi-layered.

[0010] [5] A secondary battery according to any one of [1] to [4], wherein, in the first region, the adhesive layer or tape is integrated with the insulating component.

[0011] [6] The secondary battery according to any one of [1] to [5], wherein the pair of first end sides are long sides.

[0012] [7] A secondary battery according to any one of [1] to [6], wherein the electrode body has electrode tabs at a position facing the pair of second end edges.

[0013] [8] The secondary battery according to any one of [1] to [7], wherein the electrode body is a stacked electrode body.

[0014] [9] The secondary battery according to any one of [1] to [8], wherein the thickness of the insulating member in the first region is more than 10 μm greater than the thickness of the insulating member in the second region.

[0015]

[10] The secondary battery according to any one of [1] to [9], wherein the first region has a width of 2 mm or more in the second direction.

[0016]

[11] A battery pack, wherein the battery pack comprises: a plurality of secondary batteries, the plurality of secondary batteries being any one of [1] to

[10] , arranged in the third direction; and a battery spacer disposed between the plurality of secondary batteries, wherein, when viewed from the third direction, the battery spacer is configured to overlap with the first region of the insulating member.

[0017]

[12] According to the battery pack of

[11] , the plurality of secondary batteries and the battery spacers are restricted in the third direction by a load of more than 10 kN.

[0018] The above and other objects, features, aspects and advantages of the present invention will become clear from the following detailed description relating to the invention, which will be understood in conjunction with the accompanying drawings. Attached Figure Description

[0019] Figure 1This is a front view showing the structure of the secondary battery according to the embodiment.

[0020] Figure 2 This indicates viewing from the direction of arrow II. Figure 1 The diagram shows the state of the secondary battery.

[0021] Figure 3 This indicates viewing from the direction of arrow III. Figure 1 The diagram shows the state of the secondary battery.

[0022] Figure 4 This indicates viewing from the direction of arrow IV. Figure 1 The diagram shows the state of the secondary battery.

[0023] Figure 5 This indicates viewing from the direction of arrow V. Figure 1 The diagram shows the state of the secondary battery.

[0024] Figure 6 yes Figure 1 The image shows a front cross-sectional view of a secondary battery.

[0025] Figure 7 This is a cross-sectional view of the negative electrode plate.

[0026] Figure 8 This is the front view of the negative electrode plate.

[0027] Figure 9 This is a cross-sectional view of the positive electrode plate.

[0028] Figure 10 This is the front view of the positive electrode plate.

[0029] Figure 11 It is a three-dimensional diagram showing the state where a sealing plate is installed on the current collector on the positive side.

[0030] Figure 12 It is a three-dimensional diagram showing the structure of a secondary battery.

[0031] Figure 13 This is a diagram showing the secondary battery and the battery spacer adjacent to it, viewed from the stacking direction.

[0032] Figure 14 It is a cross-sectional view of the secondary battery and the battery separator.

[0033] Figure 15 This is a perspective view showing the state in which the electrode holder is installed on the electrode body.

[0034] Figure 16 yes Figure 15 An exploded perspective view of the electrode holder shown.

[0035] Figure 17 This is a perspective view showing the state in which the electrode holder of the modified example is installed on the electrode body.

[0036] Figure 18 It constitutes Figure 17 The diagram shows the unfolded shape of the sheet-like component of the electrode holder.

[0037] Figure 19 It is a cross-sectional view showing the positional relationship between the electrode holder and the battery spacer.

[0038] Figure 20 yes Figure 19 Enlarged view of part XX in the image.

[0039] Figure 21 This diagram illustrates the process of inserting the electrode body and pressure-sensitive paper together into the housing body.

[0040] Figure 22 yes Figure 21 A sectional view of section XXII.

[0041] Figure 23 This is a diagram showing the load test of a secondary battery.

[0042] Figure 24 This is a graph showing the color development range of the pressure-sensitive paper in the comparative example secondary battery.

[0043] Figure 25 This is a diagram showing the color development range of the pressure-sensitive paper in the secondary battery of the embodiment. Detailed Implementation

[0044] The following describes the implementation of this technology. It should be noted that the same or equivalent parts are labeled with the same reference numerals, and sometimes the description is not repeated.

[0045] It should be noted that, in the embodiments described below, when numbers, quantities, etc., are mentioned, the scope of this technology is not necessarily limited to those numbers, quantities, etc., unless specifically stated otherwise. Furthermore, in the embodiments described below, each constituent element is not necessarily essential to this technology, unless specifically stated otherwise. Additionally, this technology is not limited to technologies that must achieve all the effects mentioned in this embodiment.

[0046] It should be noted that in this specification, the terms "comprise," "include," and "have" are open-ended. That is, when a structure is included, other structures besides that structure may be included, or they may not be included.

[0047] Furthermore, in this specification, when using geometric terms and terms indicating positional / directional relationships, such as "parallel," "orthogonal," "tilted at 45°," "coaxial," and "along," these terms are permissible with manufacturing errors or slight variations. In this specification, when using terms indicating relative positional relationships such as "upper side" and "lower side," these terms are used to indicate the relative positional relationship in a given state. Depending on the orientation of each mechanism (e.g., flipping the entire mechanism upside down), the relative positional relationship can be flipped or rotated to any angle.

[0048] Furthermore, the dimensions of the components illustrated in this specification, such as width, length, and diameter, are not limited to those shown in the illustrations and may be appropriately changed. In this specification, structures are sometimes labeled with ordinal numbers such as "first" or "second," but these ordinal numbers, except where explicitly specified, do not imply priority or order.

[0049] In this instruction manual, "battery" is not limited to lithium-ion batteries, but may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries. In this instruction manual, "electrode" can be collectively referred to as the positive electrode and the negative electrode. Additionally, "electrode plate" can be collectively referred to as the positive plate and the negative plate.

[0050] In this manual, "battery" can be used in hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). However, the use of "battery" is not limited to vehicle applications.

[0051] In this specification, the X direction (first direction) is sometimes referred to as the "width direction" of the secondary battery, electrode body and housing body, and similarly, the Z direction (second direction) is sometimes referred to as the "height direction" of the secondary battery, electrode body and housing body, and similarly, the Y direction (third direction) is sometimes referred to as the "thickness direction" of the secondary battery, electrode body and housing body.

[0052] (The overall structure of a secondary battery)

[0053] Reference Figures 1 to 6 The overall structure of the secondary battery 1 is described below. The secondary battery 1 includes a casing 100 (outer can), electrode bodies 200, electrode terminals 300, and current collector 400. The casing 100 includes a casing body 110, a sealing plate 120, and a sealing plate 130.

[0054] When constructing a battery pack including secondary batteries 1, multiple secondary batteries 1 are stacked in their thickness direction. The stacked secondary batteries 1 can be constrained in the stacking direction (Y direction) by a limiting member to form a battery module, or the battery pack can be directly supported on the side of the battery pack housing without using a limiting member.

[0055] The casing body 110 is composed of a cylindrical, preferably square-cylindrical, component. This allows for the production of a secondary battery 1 with a square-shaped casing 100. The casing body 110 is made of metal. Specifically, it is made of aluminum, aluminum alloy, iron, or an iron alloy.

[0056] like Figure 1 as well as Figure 2 As shown, sealing plates 120 and 130 are respectively provided at both ends of the housing body. The housing body 110 is constructed, for example, by having the end edges of a bent plate-like component abut against each other. Figure 2 The illustrated joint 115 is joined together (e.g., by energy line irradiation such as laser welding) to form a square tube shape. The corners of the "square tube" may also have an R-shape (rounded corner shape).

[0057] In this embodiment, the housing body 110 is formed such that its width (X direction) is longer than its thickness (Y direction) and height (Z direction) of the secondary battery 1. The width of the housing body 110 in the X direction is preferably 300 mm or more. This allows for the construction of a relatively large (high-capacity) secondary battery 1. The height of the housing body 110 in the Z direction is preferably 100 mm or less. This allows for the construction of a relatively low-height (low-height) secondary battery 1, for example, improving vehicle mounting capability. However, the size of the secondary battery 1 is not limited to the above-described range.

[0058] The housing body 110 includes a first side surface 111 (first surface) and a second side surface 112 (second surface). The first side surface 111 is composed of a pair of first side surface portions 111A and 111B, and the second side surface 112 is composed of a pair of second side surface portions 112A and 112B. The first side surface portions 111A and 111B form part of the side surface of the housing 100. The pair of second side surface portions 112A and 112B form the bottom surface and the top surface of the housing 100. The first side surface portions 111 and 112 are arranged to intersect each other (approximately orthogonal). The first side surface portions 111 and 112 are connected at their respective ends.

[0059] like Figure 5As shown, a gas discharge valve 150 is provided on one of the second side surfaces 112A. The gas discharge valve 150 extends along the width direction (X direction) of the secondary battery 1. The gas discharge valve 150 extends along the X direction to a degree that it does not extend from the center of the housing body 110 in the X direction to both ends. The shape of the gas discharge valve 150 can be appropriately modified.

[0060] The thickness of the plate-shaped component at the gas discharge valve 150 is thinner than the thickness of the plate-shaped components other than the gas discharge valve 150 in the housing body 110. As a result, when the pressure inside the housing 100 reaches a predetermined value or higher, the gas discharge valve 150 breaks first compared to other parts in the housing body 110, venting the gas inside the housing 100 to the outside.

[0061] like Figure 2 As shown, a joining portion 115 is formed on the other side of the second side portion 112, the second side portion 112B. The joining portion 115 extends along the width direction (X direction) of the secondary battery 1. At the joining portion 115, the end edges of the plate-shaped members constituting the housing body 110 are joined together.

[0062] like Figure 3 As shown, an opening 113 (first opening) is provided at one end of the housing body 110 in a first direction (X direction). The opening 113 is sealed by a sealing plate 120 (first sealing plate). A joint portion 115 is formed in the opening 113, and the opening 113 is sealed. The opening 113 and the sealing plate 120 have a generally rectangular shape with the short side in the Y direction and the long side in the Z direction. The generally rectangular shape includes a rectangular shape or a shape with rounded corners, etc., that is substantially rectangular.

[0063] A negative terminal 300A is provided on the sealing plate 120. The position of the negative terminal 300A can be changed as appropriate.

[0064] like Figure 4 As shown, an opening 114 (second opening) is provided at the end of the housing body 110 on the opposite side in the X direction. That is, opening 114 is located at the end opposite to opening 113, and openings 113 and 114 face each other. Opening 114 is sealed by a sealing plate 130 (second sealing plate). A joint portion 115 is formed in opening 114, and opening 114 is sealed. Opening 114 and sealing plate 130 have a generally rectangular shape with the short side in the Y direction and the long side in the Z direction.

[0065] A positive terminal 300B and a liquid injection hole 140 are provided on the sealing plate 130. The positions of the positive terminal 300B and the liquid injection hole 140 can be changed as appropriate. The liquid injection hole 140 is sealed by a sealing component (not shown). As a sealing component, blind rivets and other metal components can be used, for example.

[0066] Sealing plates 120 and 130 are made of metal. Specifically, sealing plates 120 and 130 are made of aluminum, aluminum alloy, iron, or iron alloy.

[0067] Sealing plates 120 and 130 (third side) form part of housing 100. Sealing plates 120 and 130 are arranged in a manner that intersects (approximately orthogonal) with respect to the first side portion 111 and the second side portion 112.

[0068] In the housing 100, the area (first area) of each of the pair of first side portions 111 (first surfaces) is larger than the area (second area) of each of the pair of second side portions 112 (second surfaces) and the area (third area) of each of the sealing plates 120 and 130 (third surfaces).

[0069] The negative terminal 300A is electrically connected to the negative terminal of the electrode body 200. The negative terminal 300A is mounted on the sealing plate 120, i.e., the housing 100. The positive terminal 300B is electrically connected to the positive terminal of the electrode body 200. The positive terminal 300B is mounted on the sealing plate 130, i.e., the housing 100.

[0070] The negative terminal 300A is made of a conductive material (more specifically, a metal), such as copper or a copper alloy. The positive terminal 300B is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy.

[0071] The electrode body 200 is a flat electrode body with the negative electrode plate 210 and positive electrode plate 220 (described later) stacked on top of each other. Specifically, the electrode body 200 is a stacked electrode body in which multiple negative electrode plates 210 and multiple positive electrode plates 220 are alternately stacked with a separator. The separator can be formed by folding a strip-shaped insulating sheet component or by individually setting multiple insulating sheets. In this specification, "electrode body" is not limited to a stacked electrode body; it can also be a wound electrode body formed by winding strip-shaped negative electrode plates and strip-shaped positive electrode plates together with a strip-shaped separator. The separator can be made of, for example, a microporous membrane of polyolefin.

[0072] like Figure 6 As shown, the housing 100 houses the electrode body 200. The electrode body 200 is housed within the housing 100 with its long side parallel to the X direction. Specifically, one or more stacked electrode bodies are housed in the housing 100 together with an electrolyte (not shown). As the electrolyte (non-aqueous electrolyte), for example, an electrolyte in which LiPF6 is dissolved in a non-aqueous solvent can be used. A solid electrolyte can also be used instead of the electrolyte.

[0073] The electrode body 200 includes a generally rectangular main body, a negative electrode tab group 200A, and a positive electrode tab group 200B.

[0074] The main body is composed of a negative electrode plate 210 and a positive electrode plate 220, which will be described later. The negative electrode tab assembly 200A is located at the end of the main body on one side (the sealing plate 120 side) of the electrode body 200 in the X direction. The positive electrode tab assembly 200B is located at the end of the main body on the other side (the sealing plate 130 side) of the electrode body 200 in the X direction.

[0075] The negative electrode tab group 200A and the positive electrode tab group 200B are formed to protrude from the central part of the electrode body 200 toward the sealing plate 120 or the sealing plate 130, respectively.

[0076] 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 composed of plate-shaped components. The electrode body 200 is electrically connected to the negative terminal 300A and the positive terminal 300B via the current collector 400.

[0077] The negative current collector 400A is disposed on the sealing plate 120 through a resin insulating component. The negative current collector 400A is electrically connected to the negative electrode tab assembly 200A and the negative terminal 300A. The negative current collector 400A is made of a conductive material (more specifically, a metal), such as copper or a copper alloy.

[0078] The positive current collector 400B is disposed on the sealing plate 130 through a resin insulating component. The positive current collector 400B is electrically connected to the positive electrode tab assembly 200B and the positive terminal 300B. The positive current collector 400B is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy. The positive electrode tab assembly 200B can also be electrically connected to the sealing plate 130 directly or via the positive current collector 400B. In this case, the sealing plate 130 can also function as the positive terminal 300B.

[0079] (Structure of electrode body 200)

[0080] like Figure 7 as well as Figure 8As shown, the negative electrode plate 210 includes a negative electrode core 211 and a negative electrode active material layer 212. At one end of the negative electrode plate 210 in the width direction, a negative electrode tab 200A0 formed by the negative electrode core 211 is provided. When stacking the negative electrode plates 210, multiple negative electrode tabs 200A0 are stacked to form a negative electrode tab group 200A. The negative electrode tab group 200A is electrically connected to the negative electrode. The length of each negative electrode tab 200A0 in the protruding direction of the multiple negative electrode plates 210 is appropriately adjusted considering the connection state between the negative electrode tab group 200A and the negative electrode current collector 400A. The shape of the negative electrode tab 200A0 is not limited to... Figure 8 The illustrated shape.

[0081] like Figure 9 as well as Figure 10 As shown, the positive electrode plate 220 includes a positive electrode core 221, a positive electrode active material layer 222, and a positive electrode protective layer 223. At one end of the positive electrode plate 220 in the width direction, a positive electrode tab 200B0 composed of the positive electrode core 221 is provided. When stacking the positive electrode plates 220, multiple positive electrode tabs 200B0 are stacked to form a positive electrode tab assembly 200B. The positive electrode tab assembly 200B is electrically connected to the positive electrode. The length of each positive electrode tab 200B0 in the protruding direction of the multiple positive electrode plates 220 is appropriately adjusted considering the connection state between the positive electrode tab assembly 200B and the positive current collector 400B. The shape of the positive electrode tab 200B0 is not limited to... Figure 10 The illustrated shape.

[0082] A positive electrode protection layer 223 is provided at the root of the positive electrode tab 200B0. However, it is not always necessary to provide a positive electrode protection layer 223 at the root of the positive electrode tab 200B0.

[0083] (Containment of electrode body 200)

[0084] The electrode body 200, with the positive electrode tab group 200B side as the front, is inserted into the housing body 110 through the opening 113. For example... Figure 11 As shown, a spacer 500 is provided between the electrode body 200 and the sealing plate 130 on the positive electrode side. A spacer 500 is also provided between the electrode body 200 and the sealing plate 120 on the negative electrode side, similar to the one on the positive electrode side.

[0085] Alternatively, the electrode body 200 can be electrically connected to the negative terminal 300A before being inserted into the housing body 110. After the electrode body 200 is inserted into the housing body 110, it can be electrically connected to the positive terminal 300B.

[0086] After inserting the electrode body 200 into the housing body 110, as Figure 12As shown, sealing plates 120 and 130 are joined to the housing body 110. Sealing plate 120 seals the opening 113 of the housing body 110, and sealing plate 130 seals the opening 114 of the housing body 110. Thus, the electrode body 200 is housed in the housing 100.

[0087] (Structure of the battery pack)

[0088] like Figure 13 As shown, the first side portion 111 of the housing body 110 has a generally rectangular shape including a pair of first end edges 101 extending in the X direction and a pair of second end edges 102 extending in the Z direction. Here, the pair of first end edges 101 are longer than the pair of second end edges 102. That is, the first side portion 111 has a generally rectangular shape with the X direction being the long side direction and the Z direction being the short side direction.

[0089] In the configuration of the battery pack, multiple secondary batteries 1 are arranged side-by-side in the Y direction. Battery spacers 2 are disposed between the multiple secondary batteries 1. The multiple secondary batteries 1 and the battery spacers 2 are constrained in the Y direction by a specified load.

[0090] like Figure 13 As shown, when viewed from the Y direction, the area of ​​the battery spacer 2 is smaller than the area of ​​the first side portion 111 of the housing body 110. Specifically, in the Z direction, the battery spacer 2 is located in a region that is a distance H (e.g., H = approximately 3 mm) from the inner side of the pair of first end edges 101, and in the X direction, the battery spacer 2 is located in a region that is a distance L (e.g., L = approximately 15 mm) from the inner side of the pair of second end edges 102.

[0091] The electrode body 200 has a main body 200C that is generally rectangular in shape, excluding the negative electrode tab group 200A and the positive electrode tab group 200B (electrode tabs). The separation distance (first distance) between the inner surface of the housing 100 in the Z direction and the main body 200C of the electrode body 200 is smaller than the separation distance (second distance) between the inner surface of the housing 100 in the X direction and the main body 200C of the electrode body 200.

[0092] like Figure 14 As shown, when a limiting load in the Y direction is applied to the housing body 110 from the battery spacer 2, the housing body 110 deforms more at its central portion in the Z direction than at its ends in the Z direction. Thus, when a load is applied in the Y direction, the area near the first end edge 101 ( Figure 14 The A portion of the electrode is difficult to deform, and the pressure load tends to decrease relatively. As described later, the electrode holder 600 in this embodiment has a structure that suppresses the reduction of the pressure load near the first end edge 101.

[0093] (Structure of electrode holder 600)

[0094] like Figure 15 As shown, an electrode holder 600 (insulating component) is provided on the outside of the electrode body 200. The electrode holder 600 is made of an insulating sheet material. The electrode holder 600 and the electrode body 200 are housed together in the housing 100.

[0095] The electrode holder 600 is made of resin, for example. Polyethylene (PE) or polypropylene (PP) is preferably used as the resin constituting the electrode holder 600. However, the resin constituting the electrode holder 600 is not limited to these; for example, olefin resins such as polymethylpentene (PMP), polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), fluoropolymers such as polytetrafluoroethylene (PTFE), acrylic resins (PMMA), polyimide (PI), polyphenylene ether (PPE), cellulose triacetate (TAC), polyphenylene sulfide resin (PPS), polycarbonate (PC), nylon, etc., can be used. The electrode holder 600 can be porous or non-porous.

[0096] The electrode holder 600 can be formed in a cylindrical shape, or in a box or bag shape. The electrode holder 600 preferably has an area through which electrolyte and gas can pass. This area is preferably opposite to the gas discharge valve 150. This allows gas generated within the electrode 200 to be easily discharged to the outside of the housing 100 via the gas discharge valve 150.

[0097] The electrode holder 600 has a first region 610 and a second region 620. The first region 610 is located at the end in the Z direction, near a pair of first end edges 101 of the housing body 110. The first region 610 extends in a strip shape in the X direction. The first region 610 preferably extends continuously. However, the first region 610 may also be formed discontinuously. Figure 15 As shown, the first region 610 is preferably provided along the entire length of the main body 200C of the electrode body 200 in the X direction. However, the first region 610 may also be provided only in a part of the main body 200C of the electrode body 200.

[0098] The second region 620 is disposed between the two first regions 610. The second region 620 is located in the Z direction at a position closer to the center of the electrode body holder 600 than the first regions 610. The first region 610 is configured to overlap with the main body portion 200C of the electrode body 200 (in the case of a wound electrode body, a flat surface except for the curved portion at the Z direction end) in the Y direction.

[0099] like Figure 16As shown in the exploded perspective view, the electrode holder 600 is composed of a first component 601, a second component 602, a third component 603, and a fourth component 604. Figure 15 In the first region 610 on the upper-middle side (+Z side), the first component 601 overlaps with the third component 603 and the fourth component 604. Figure 15 In the first region 610 on the lower middle side (-Z side), the second component 602 overlaps with the third component 603 and the fourth component 604. Therefore, the thickness of the electrode holder 600 in the first region 610 is greater than the thickness of the electrode holder 600 in the second region 620.

[0100] The first component 601, the second component 602, the third component 603, and the fourth component 604 are each made of sheet material. The first component 601, the second component 602, the third component 603, and the fourth component 604 can be made of the same material or different materials. The first component 601, the second component 602, the third component 603, and the fourth component 604 can have the same thickness or different thicknesses. The first component 601 and the second component 602 are preferably disposed on the outer side (the side not facing the electrode body 200) of the first region 610 relative to the third component 603 and the fourth component 604. By configuring the stepped portion of the electrode body holder 600 formed at the end of the first region 610 to not directly contact the electrode body 200, the generation of surface pressure difference caused by the stepped portion can be suppressed.

[0101] exist Figure 15 , Figure 16 The example illustrates a structure with a first region 610 set on both the +Z and -Z sides, but it can also be implemented as follows: Figure 17 As in the example, the first region 610 is set only on the -Z side. In this case, as... Figure 18 As shown, by winding a sheet component onto the electrode body 200 and overlapping its ends, a first region 610 with a relatively large thickness can be formed. Alternatively, it can be replaced with... Figure 17 For example, the first region 610 is set only on the +Z side.

[0102] As described above, the first region 610 can be formed by overlapping multiple layers of sheets constituting the electrode body holder 600. Figures 15 to 18 In the example, two sheets are overlapped in the first region 610, but three or more sheets can also be overlapped.

[0103] Alternatively, instead of overlapping the sheets that constitute the electrode holder 600, an adhesive layer or tape can be integrated with the sheet to form the first region 610. In this case, the adhesive layer or tape integrated with the sheet constitutes the electrode holder 600.

[0104] The thickness of the electrode holder 600 in the first region 610 is preferably 10 μm or more thicker than the thickness of the electrode holder 600 in the second region 620, more preferably 20 μm or more thicker, and even more preferably 30 μm or more thicker.

[0105] The first region 610 has a size of 2 mm or more, more preferably 5 mm or more, and even more preferably 8 mm or more in the Z direction (second direction).

[0106] like Figure 19 As shown, when viewed from the Y direction (third direction), the battery spacer 2 is configured to overlap with the first region 610 of the electrode holder 600. The height (Z-direction dimension) of the portion of the first region 610 that does not overlap with the battery spacer 2 in the Y direction is preferably greater than 1% or more of the height (Z-direction dimension) of the housing body 110. When viewed from the Y direction, the first region 610 is preferably configured to overlap with the positive electrode plate 220.

[0107] In one example, the thickness of the housing body 110 is approximately 0.65 mm. The secondary battery 1 and the battery spacer 2 are preferably subjected to a load of 10 kN or more in the Y direction. The limiting pressure in the Y direction based on the battery spacer 2 is, for example, between 0.5 MPa and 2 MPa.

[0108] As described above, since the corners of the housing body 110 are difficult to deform, when the housing 100 is constrained in the Y direction to form a battery pack, the pressure load near the first end edge 101 of the housing body 110 tends to be relatively small. If a deviation in the pressure load causes a deviation in the potential within the positive electrode plate 220 of the electrode body 200, metal deposition (lithium deposition in lithium-ion batteries) may occur.

[0109] In contrast, in the secondary battery 1 of this embodiment, by relatively increasing the thickness of the electrode holder 600 in the first region 610 located at both ends in the Z direction, the reduction of the pressure load near the first end edge 101 of the housing body 110 can be suppressed. Therefore, lithium deposition (metal deposition) can be effectively suppressed in the part where the pressure load tends to be relatively small.

[0110] The aforementioned effects can be confirmed, for example, using the methods shown below. Figure 21 , Figure 22As shown, with the pressure-sensitive paper 700 overlapping the electrode body 200 and the electrode body holder 600 in the thickness direction (Y direction) of the electrode body 200, the electrode body 200, the electrode body holder 600, and the pressure-sensitive paper 700 are inserted into the housing body 110. The pressure-sensitive paper 700 is a sheet component that develops color when a specified pressure is applied.

[0111] Battery spacers 2 are installed on both sides of the secondary battery 1. A testing machine 3 capable of pressing in with any load is used to apply the compressive load in the direction of arrow DR3. Afterward, the secondary battery 1 is disassembled, and the pressure-sensitive paper 700 is removed from the housing body 110 to confirm the color development range.

[0112] In the secondary battery 1 (comparative example) where the first region 610 is not set, such as Figure 24 As shown, a pressure-sensitive area 700A (color-developing range) is formed on the central side of the housing body 110. In contrast, when a lower pressure load is applied to the portion near the first end edge 101, a non-pressure-sensitive area 700B (non-color-developing area) is formed.

[0113] In the settings Figures 15 to 20 In the secondary battery 1 (implementation method) of the first region 610 shown, as Figure 25 As shown, a pressure-sensitive region 700A is formed over the entire area of ​​the pressure-sensitive paper 700, including the portion near the first end edge 101. Therefore, it can be confirmed that the reduction in pressure load in the portion near the first end edge 101 is suppressed.

[0114] Embodiments of the invention have been described, but the embodiments disclosed herein should be considered illustrative rather than limiting in all respects. The scope of the invention is set forth in the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A secondary battery, wherein, The secondary battery has the following features: An electrode body, the electrode body comprising a main body and electrode tabs; An insulating component, wherein the insulating component is disposed on the outside of the electrode body; and An outer can, which is square in shape, houses the electrode body and the insulating components. The outer can has a pair of first faces, a pair of second faces substantially orthogonal to the first faces, and a pair of third faces substantially orthogonal to the first and second faces, wherein the area of ​​the first faces is larger than the area of ​​the second faces and the area of ​​the third faces. The first surface has a generally rectangular shape including a pair of first end edges extending along a first direction and a pair of second end edges extending along a second direction that is generally orthogonal to the first direction. The insulating component has a first region and a second region. The first region is disposed near at least one of the pair of first end edges and extends in a strip shape along the first direction. The second region is located in the second direction at a position closer to the center of the insulating component than the first region. The first region and the second region are configured to overlap with the main body of the electrode body in a third direction orthogonal to the first direction and the second direction, respectively. The thickness of the insulating component in the first region is greater than the thickness of the insulating component in the second region.

2. The secondary battery as described in claim 1, wherein, The first region is located near both of the pair of first end edges.

3. The secondary battery as described in claim 1 or 2, wherein, The first region is provided along the entire length of the main body of the electrode body in the first direction.

4. The secondary battery as described in claim 1 or 2, wherein, In the first region, the sheets constituting the insulating component are overlapped in multiple layers.

5. The secondary battery as described in claim 1 or 2, wherein, In the first region, the adhesive layer or tape is integrated with the insulating component.

6. The secondary battery as described in claim 1 or 2, wherein, The first end edge of the pair is the longer edge.

7. The secondary battery as described in claim 1 or 2, wherein, The electrode body has electrode tabs at the position facing the pair of second end edges.

8. The secondary battery as described in claim 1 or 2, wherein, The electrode body is a stacked electrode body.

9. The secondary battery as described in claim 1 or 2, wherein, The thickness of the insulating component in the first region is more than 10 μm greater than the thickness of the insulating component in the second region.

10. The secondary battery as described in claim 1 or 2, wherein, The first region has a width of more than 2 mm in the second direction.

11. A battery pack, wherein, The battery pack includes: A plurality of secondary batteries, wherein the plurality of secondary batteries are the secondary batteries according to claim 1 or 2, are arranged upwards in the third direction; and A battery spacer is disposed between the plurality of secondary batteries. When viewed from the third-party perspective, the battery spacer is configured to overlap with the first region of the insulating component.

12. The battery pack of claim 11, wherein, The plurality of secondary batteries and the battery spacer are restricted to a load of more than 10 kN in the third direction.

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