Battery and carrying structure thereof

Abstract

The invention relates to a battery and a mounting structure thereof. In a battery (1), a case (100) has an outer surface including a first surface (120, 130) extending in a direction of a plane including a first direction, and a second surface (112A) connected to one end of the first surface (120, 130) in the first direction and substantially orthogonal to the first surface (120, 130), and a gas discharge valve (150) provided on the second surface (112A). The electrode body (200) and the current collector (400) are joined at first joining parts (411, 421), the current collector (400) and the electrode terminal (300) are joined at second joining parts (431, 441), and at least one of the first joining parts (411, 421) and the second joining parts (431, 441) is biased toward the second surface (112A) in the first direction.

Description

Technical Field

[0001] This technology relates to batteries and their mounting structures. Background Technology

[0002] Previously, batteries containing electrodes within a casing were known. Conventionally, a structure was employed where a portion of the casing cracked and the contents were expelled when the temperature of the electrodes rose.

[0003] For example, Japanese Patent Application Publication No. 2022-185087 discloses a structure in which electrode terminals and a gas discharge valve are provided on the upper surface (sealing plate) of a square secondary battery.

[0004] U.S. Patent Application Publication No. 2023 / 0187770 discloses a structure in which electrode terminals are provided on both sides (sealing plates) of the frame of a square secondary battery, and a gas exhaust valve is provided on the bottom surface of the frame. Summary of the Invention

[0005] From the perspective of improving battery reliability, it is necessary to suppress cracking at unexpected locations when the temperature of the electrode body rises. From this point of view, there is still room for improvement in conventional batteries.

[0006] The purpose of this technology is to provide a highly reliable battery and its mounting structure.

[0007] This technology provides the following battery and its mounting structure.

[0008] [1] A battery comprising an electrode body and a housing for receiving the electrode body, wherein the housing has an outer surface and a gas vent valve, the outer surface comprising a first surface and a second surface, the first surface extending along a direction including a first direction, the second surface being connected to one end of the first surface in the first direction and substantially orthogonal to the first surface, the gas vent valve being disposed on the second surface, the battery further comprising: an electrode terminal disposed outside the first surface of the housing; and a current collector disposed inside the first surface of the housing, the electrode body and the current collector being joined at a first joint, the current collector and the electrode terminal being joined at a second joint, at least one of the first joint and the second joint being biased toward the second surface side in the first direction.

[0009] It should be noted that, in this technology, "biased to the second surface" is not limited to the case where the first joint or the second joint is located only on the second surface side closer to the center in the first direction. It also includes the following cases: a part of the first joint or the second joint is located on the opposite side relative to the second surface, but more than half of the area of ​​the first joint or the second joint (the projected area projected onto the first surface) (preferably more than 60%, more preferably more than 70%, and even more preferably more than 80% or more than 90%) is located on the second surface side.

[0010] [2] In the battery described in [1], the gas discharge valve is provided only at a central location on the second surface in a second direction that is substantially orthogonal to the first surface.

[0011] [3] In the battery described in [1], the electrode body has a main body and an electrode tab that protrudes from the main body toward the first surface at an end in a second direction substantially orthogonal to the first surface, and the first joint is formed between the electrode tab and the current collector.

[0012] [4] In the battery described in [3], the first joint is formed by laser welding.

[0013] [5] In the battery described in [3] or [4], the second joint is formed by riveting.

[0014] [6] In any one of [1] to [5], the electrode body includes a positive electrode, a negative electrode stacked on the positive electrode, and a separator disposed between the positive electrode and the negative electrode.

[0015] [7] In the battery described in [6], the outer surface of the casing further includes a third surface, which is connected to another end of the first surface in the first direction and faces the second surface in the first direction. The separator is configured to protrude in the first direction from the positive electrode and the negative electrode toward the second surface and the third surface, and the amount of protrusion of the separator relative to the positive electrode and the negative electrode in the first direction is greater on the second surface than on the third surface.

[0016] [8] In any one of [1] to [6], the outer surface of the casing further includes a third surface, which is connected to the other end of the first surface in the first direction and faces the second surface in the first direction. When the distance between the second surface and the third surface in the first direction is set as H, the first joint is formed in a region in the first direction at a distance of more than 1 / 10H and less than 4 / 10H from the second surface.

[0017] [9] In any one of [1] to [8], the conductive area at the first junction is smaller than 0.3 times the conductive area of ​​the current collector.

[0018]

[10] In any one of [1] to [8], the conductive area at the second junction is smaller than 0.2 times the conductive area of ​​the current collector.

[0019]

[11] In any one of [1] to

[10] , in the casing, the thickness of the first plate-shaped portion constituting the first surface is three times greater than the thickness of the second plate-shaped portion constituting the second surface.

[0020]

[12] A battery mounting structure, which is the battery mounting structure of any one of [1] to

[11] , wherein the second side of the housing is disposed below.

[0021] 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

[0022] Figure 1 This is a front view showing the structure of a secondary battery according to one embodiment.

[0023] Figure 2 This indicates viewing from the direction of arrow II. Figure 1 The diagram shows the state of the secondary battery.

[0024] Figure 3 This indicates viewing from the direction of arrow III. Figure 1 The diagram shows the state of the secondary battery.

[0025] Figure 4 This indicates viewing from the direction of arrow IV. Figure 1 The diagram shows the state of the secondary battery.

[0026] Figure 5 This indicates viewing from the direction of arrow V. Figure 1 The diagram shows the state of the secondary battery.

[0027] Figure 6 yes Figure 1 The image shows a front cross-sectional view of a secondary battery.

[0028] Figure 7 This is a cross-sectional view of the negative electrode plate.

[0029] Figure 8 This is the front view of the negative electrode plate.

[0030] Figure 9 This is a cross-sectional view of the positive electrode plate.

[0031] Figure 10 This is the front view of the positive electrode plate.

[0032] Figure 11 yes Figure 1 The XI-XI cross-sectional view of the secondary battery shown.

[0033] Figure 12 yes Figure 1 The XII-XII cross-sectional view of the secondary battery is shown.

[0034] Figure 13 This is a flowchart illustrating a method for manufacturing a secondary battery according to one embodiment.

[0035] Figure 14 This is a schematic diagram illustrating an example of the configuration of a first joint and a second joint in a secondary battery according to one embodiment.

[0036] Figure 15 This is a three-dimensional view showing the first joint of an example.

[0037] Figure 16 This is a three-dimensional view showing an example of the second joint.

[0038] Figure 17 yes Figure 16 Sectional view of XVII-XVII. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] In this 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 manual, "electrode" can be collectively referred to as the positive electrode and the negative electrode.

[0044] In the accompanying drawings, when the electrode body of the secondary battery is a stacked electrode body, the direction of the long side of the stacked surface is designated as the X direction; when the electrode body is a wound electrode body, the direction along its winding axis is designated as the X direction. Furthermore, when viewed from the X direction, the direction of the short side of the electrode body is designated as the Y direction, and when viewed from the X direction, the direction of the long side of the electrode body is designated as the Z direction. For ease of understanding of the invention, there are portions in the drawings where the dimensions of each structure are shown as variations from the actual dimensions.

[0045] In this application specification, the Z direction, which is the first direction, is sometimes referred to as the "height direction" of the secondary battery, electrode body, and housing body; similarly, the X direction, which is the second direction, is sometimes referred to as the "width direction" of the secondary battery, electrode body, and housing body; and similarly, the Y direction, which is the third direction, is sometimes referred to as the "thickness direction" of the secondary battery, electrode body, and housing body.

[0046] (The overall structure of the battery)

[0047] Figure 1 This is a front view of the secondary battery 1 according to the embodiment. Figures 2 to 5 These represent observations from the directions of arrows II, III, IV, and V, respectively. Figure 1 The diagram shows the state of secondary battery 1. Figure 6 yes Figure 1 The front cross-sectional view of the secondary battery 1 shown.

[0048] The secondary battery 1 can be installed in electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs). However, the application of the secondary battery 1 is not limited to vehicle use.

[0049] like Figures 1 to 6 As shown, the secondary battery 1 includes a housing 100, an electrode body 200, an electrode terminal 300, and a current collector 400. The housing 100 includes a housing body 110, a sealing plate 120 (first sealing plate), and a sealing plate 130 (second sealing plate).

[0050] When constructing a battery pack containing 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 constraining member to form a battery module, or multiple secondary batteries 1 can be housed in the battery pack housing without using a constraining member.

[0051] The housing body 110 is composed of a cylindrical, preferably square, cylindrical component. This results in a square secondary battery 1. The housing body 110 is made of metal. Specifically, the housing body 110 is made of aluminum, aluminum alloy, iron, or iron alloy, etc.

[0052] 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 can be constructed, for example, by having the end edges of bent plate-like components abut against each other. Figure 2 The illustrated joint 115 is joined together (e.g., by laser welding) to form a square tube shape. The corners of the "square tube shape" may also have an R shape (rounded corner shape).

[0053] 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 30 cm 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 20 cm or less, more preferably 15 cm or less, and even more preferably 10 cm or less. This allows for the construction of a relatively low-height secondary battery 1, for example, improving its vehicle-mountability.

[0054] The housing body 110 includes a pair of first side faces 111 and a pair of second side faces 112. The pair of first side faces 111 form part of the side face of the housing 100. The pair of second side faces 112 form the bottom surface 112A and the upper surface 112B of the housing 100. The pair of first side faces 111 and the pair of second side faces 112 are respectively arranged to intersect each other. The pair of first side faces 111 and the pair of second side faces 112 are connected at their respective ends. Preferably, the area of ​​each of the pair of first side faces 111 is larger than the area of ​​each of the pair of second side faces 112.

[0055] like Figure 5 As shown, a gas discharge valve 150 is provided on the bottom surface 112A of one of the pair of second side surfaces 112. Figure 5 In this example, the gas discharge valve 150 is only located at a position near the center of the secondary battery 1 in the width direction (X direction). The shape and configuration of the gas discharge valve 150 on the bottom part 112A can be appropriately changed.

[0056] 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, discharging the gas inside the housing 100 to the outside.

[0057] like Figure 2 As shown, a joining portion 115 is formed on the upper surface portion 112B, which is the other of a pair of second side portions 112. 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.

[0058] like Figure 3 As shown, an opening 113 (first opening) is provided at the end of the first side in the X direction of the housing body 110. The opening 113 is sealed by a sealing plate 120. 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 whose corners are rounded, etc., that is substantially rectangular.

[0059] A negative terminal 301 is provided on the sealing plate 120 (first sealing plate). The position of the negative terminal 301 can be changed appropriately.

[0060] like Figure 4As shown, an opening 114 (second opening) is provided at the end of the second side of the housing body 110 in the X direction, opposite to the first side. That is, the opening 114 is located at the end opposite to the opening 113, and the openings 113 and 114 face each other. The opening 114 is sealed by a sealing plate 130. The opening 114 and the sealing plate 130 have a generally rectangular shape with the short side in the Y direction and the long side in the Z direction.

[0061] A positive terminal 302 and a liquid injection hole 130A are provided on the sealing plate 130 (second sealing plate). The positions of the positive terminal 302 and the liquid injection hole 130A can be changed appropriately.

[0062] 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.

[0063] The negative terminal 301 (first electrode terminal) is electrically connected to the negative terminal of the electrode body 200. The negative terminal 301 is mounted on the sealing plate 120, i.e., the housing 100.

[0064] The positive terminal 302 (second electrode terminal) is electrically connected to the positive electrode of the electrode body 200. The positive terminal 302 is mounted on the sealing plate 130, i.e., the housing 100.

[0065] The negative terminal 301 is made of a conductive material (more specifically, a metal), such as copper or a copper alloy. Alternatively, a portion or layer made of aluminum or an aluminum alloy may be provided on the outer surface of the negative terminal 301.

[0066] The positive terminal 302 is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy.

[0067] The injection port 130A is sealed by a sealing component (not shown). As the sealing component, a blind rivet or other metal component may be used.

[0068] Electrode body 200 is a flat electrode body with stacked positive and negative electrode plates (described later). Specifically, electrode body 200 is a stacked electrode body formed by alternately stacking multiple positive and multiple negative electrode plates separated by a separator 800 (described later). However, in this specification, "electrode body" is not limited to a stacked electrode body, and may also be a wound electrode body formed by winding strip-shaped positive and negative electrode plates together separated by a strip-shaped separator. Separator 800 may be made of, for example, a microporous membrane of polyolefin.

[0069] like Figure 6 As shown, the housing 100 houses the electrode body 200. Figure 6In this example, the first electrode body 201, which will be described later, is illustrated. The first electrode body 201 is housed within the housing 100 such that its long side is parallel to the X direction.

[0070] Specifically, one or more stacked electrode bodies are housed together with an electrolyte (electrolyte) inside the insulating sheet 700, which is disposed within the housing 100. For example, an electrolyte (non-aqueous electrolyte) can be prepared by dissolving LiPF6 in a non-aqueous solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) in a volume ratio (25°C) of 30:30:40 at a concentration of 1.2 mol / L.

[0071] The first electrode body 201 includes a generally rectangular main body, a negative electrode tab group 220 (first electrode tab group), and a positive electrode tab group 250 (second electrode tab group).

[0072] The main body is composed of a negative electrode plate 210 and a positive electrode plate 240, which will be described later. The negative electrode tab assembly 220 is located at the end of the main body on the sealing plate 120 side of the first electrode body 201 in the X direction. The positive electrode tab assembly 250 is located at the end of the main body on the sealing plate 130 side of the first electrode body 201 in the X direction.

[0073] The negative electrode tab group 220 and the positive electrode tab group 250 are formed to protrude from the central portion of the electrode body 200 toward the sealing plate 120 or the sealing plate 130, respectively.

[0074] The current collector 400 includes a negative current collector 401 and a positive current collector 402. The electrode body 200 is electrically connected to the negative terminal 301 and the positive terminal 302 via the current collector 400.

[0075] The negative current collector 401 is disposed on the sealing plate 120 through a resin insulating component. The negative current collector 401 is electrically connected to the negative electrode tab assembly 220 and the negative terminal 301. The negative current collector 401 is made of a conductive material (more specifically, a metal), such as copper or a copper alloy. Details of the negative current collector 401 will be described later.

[0076] The positive current collector 402 is disposed on the sealing plate 130 through a resin insulating component. The positive current collector 402 is electrically connected to the positive electrode tab assembly 250 and the positive terminal 302. The positive current collector 402 is made of a conductive material (more specifically, a metal), such as aluminum or an aluminum alloy. Details of the positive current collector 402 will be described later.

[0077] (Structure of electrode body 200)

[0078] Figure 7This is a cross-sectional view of the negative electrode plate 210. Figure 8 (Sectional view VII-VII in the middle) Figure 8 This is a front view showing the negative electrode plate 210. (Example) Figure 7 As shown, a negative electrode active material layer 212 is formed on the negative electrode core 211.

[0079] like Figure 8 As shown, at one end of the negative electrode plate 210 in the width direction, a plurality of negative electrode tabs 230 (first electrode tabs) composed of negative electrode cores 211 are provided. When the negative electrode plates 210 are stacked, the plurality of negative electrode tabs 230 are stacked to form a negative electrode tab group 220. The length of the protruding direction of each of the negative electrode tabs 230 in the plurality of negative electrode plates 210 is appropriately adjusted considering the connection state between the negative electrode tab group 220 and the negative current collector 401. The shape of the negative electrode tabs 230 is not limited to... Figure 8 The illustrated shape.

[0080] Figure 9 This is a cross-sectional view of the positive electrode plate 240. Figure 10 (IX-IX section view) Figure 10 This is a front view showing the positive electrode plate 240. For example... Figure 9 As shown, a positive electrode active material layer 242 is formed on the positive electrode core 241.

[0081] like Figure 10 As shown, at one end of the formed positive electrode plate 240 in the width direction, a plurality of positive electrode tabs 260 (second electrode tabs) composed of positive electrode cores 241 are provided. When the positive electrode plates 240 are stacked, the plurality of positive electrode tabs 260 are stacked to form a positive electrode tab assembly 250. The length of each positive electrode tab 260 in the protruding direction of the plurality of positive electrode plates 240 is appropriately adjusted considering the connection state between the positive electrode tab assembly 250 and the positive current collector 402. The shape of the positive electrode tabs 260 is not limited to... Figure 10 The illustrated shape.

[0082] A positive electrode protective layer 243 is provided at the root of the positive electrode tab 260. Alternatively, the positive electrode protective layer 243 may not necessarily be provided at the root of the positive electrode tab 260.

[0083] In a typical example, the thickness of the negative electrode tab 230 (one sheet) is less than the thickness of the positive electrode tab 260 (one sheet). In this case, the thickness of the negative electrode tab group 220 is less than the thickness of the positive electrode tab group 250.

[0084] (Connection structure between electrode 200 and current collector 400)

[0085] Figure 11 yes Figure 1 The image shows a cross-sectional view of the secondary battery along line XI-XI. Figure 11As 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 respectively include a positive electrode and a negative electrode. The electrode body 200 may also be composed of three or more electrode bodies.

[0086] The electrode body 200 is formed by overlapping 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.

[0087] The first electrode 201 includes a negative electrode tab assembly 220. A first end 205 of the negative electrode tab assembly 220 in the X direction is electrically connected to a current collector 410 (negative current collector). The second electrode 202 includes a negative electrode tab assembly 270. A third end 207 of the negative electrode tab assembly 270 in the X direction is electrically connected to other current collectors 410 (negative current collectors).

[0088] The negative electrode tab assembly 220 has a bent portion 221 and a front portion 222. The bent portion 221 is the part of the negative electrode tab assembly 220 that is bent relative to the front portion 222 on the side connected to the first electrode.

[0089] The negative electrode tab assembly 270 has a bent portion 271 and a front portion 272. The bent portion 271 is the portion of the negative electrode tab assembly 270 that is bent relative to the front portion 272 on the side connected to the first electrode.

[0090] The negative electrode tab group 220 and the negative electrode tab group 270 are bent in opposite directions with their front ends 222 and 272 approaching each other. In this embodiment, the front ends 222 and 272 are separated, but this structure is not limited to this structure, and the front ends 222 and 272 may also contact each other.

[0091] The negative current collector 401 electrically connects the negative terminal 301 to the negative electrode tab group 220 and the negative electrode tab group 270. In this embodiment, the negative current collector 401 is connected to the negative terminal 301 between the electrode body 200 and the sealing plate 120.

[0092] The negative current collector 401 includes two current collectors 410 and 430.

[0093] Current collector 410 is a plate-shaped component. Current collector 410 has a long side in the Z direction and a short side in the Y direction. Current collector 430 is also a plate-shaped component. Current collector 430 has a long side in the Z direction and a short side in the Y direction. Current collectors 410 and 430 are arranged in the X direction. Thus, current collectors 410 and 430 are composed of separate components.

[0094] The negative electrode tabs 220 and 270 are joined to the current collector 410 at the first joint 411, which will be described later. The first joint 411 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, riveting, etc. In this embodiment, the negative electrode tabs 220 and the current collector 410, as well as the negative electrode tabs 270 and the other current collector 410, are joined by, for example, ultrasonic joining.

[0095] Current collector 430 is electrically connected to one current collector 410 and other current collectors 410. Current collector 430 is connected to negative terminal 301 at a second joint 431. The connection between current collector 430 and negative terminal 301 can be formed, for example, by riveting and / or welding.

[0096] The negative terminal 301 is exposed on the outside of the sealing plate 120. The negative terminal 301 is connected to the plate-shaped component 303. It should be noted that the negative terminal 301 preferably includes a region 301A made of copper or copper alloy and a region 301B made of aluminum or aluminum alloy, and the region 301A made of copper or copper alloy is connected to the current collector 430.

[0097] The plate-shaped component 303 is located on the outside of the sealing plate 120. The plate-shaped component 303 is configured along the sealing plate 120. The plate-shaped component 303 is conductive. The plate-shaped component 303 is configured to ensure the connection area, etc., with the busbar that electrically connects the secondary battery 1 and other adjacent secondary batteries. The connection between the negative terminal 301 and the plate-shaped component 303 can be formed, for example, by laser welding.

[0098] An insulating component 510 is disposed between the plate-shaped component 303 and the sealing plate 120. An insulating component 520 is disposed between the negative terminal 301 and the sealing plate 120. An insulating component 530 is disposed between the current collector 430 and the sealing plate 120.

[0099] However, the negative terminal 301 can also be electrically connected to the sealing plate 120. In addition, the sealing plate 120 can also function as the negative terminal 301.

[0100] A spacer 600 (first spacer), described later, is disposed between the sealing plate 120 and the main body of the electrode body 200 (excluding the negative electrode tab assembly 220). The spacer 600 is made of an insulating resin component. The negative electrode tab assembly 220 passes through the interior of the spacer 600, thereby protecting the negative electrode tab assembly 220. It should be noted that a structure without the spacer 600 (first spacer) may also be used.

[0101] A resin insulating sheet 700 (electrode holder) is disposed between the electrode body 200 and the housing 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).

[0102] Figure 12 yes Figure 1 The diagram shows a cross-sectional view of the secondary battery along line XII-XII. The connection structure between the electrode body 200 and the current collector 400 on the positive electrode side of the secondary battery 1 in this embodiment differs from that on the negative electrode side in that the portion corresponding to one current collector 410 and the other current collectors 410 on the negative electrode side is constituted by a single component.

[0103] The first electrode 201 includes a positive electrode tab assembly 250. The second end 206 of the positive electrode tab assembly 250 in the X direction is electrically connected to the current collector 420 (positive current collector). The second electrode 202 includes a positive electrode tab assembly 280. The fourth end 208 of the positive electrode tab assembly 280 in the X direction is electrically connected to the current collector 420 (positive current collector).

[0104] The positive electrode tab assembly 250 has a bent portion 251 and a front portion 252. The bent portion 251 is the part of the positive electrode tab assembly 250 that is bent relative to the front portion 252 on the side where the second electrode is connected.

[0105] The positive electrode tab assembly 280 has a bent portion 281 and a front portion 282. The bent portion 281 is the part of the positive electrode tab assembly 280 that is bent relative to the front portion 282 on the side where the second electrode is connected.

[0106] The positive electrode tab group 250 and the positive electrode tab group 280 are bent in opposite directions with their front ends 252 and 282 approaching each other. In this embodiment, the front ends 252 and 282 are separated, but this structure is not limited to this structure, and the front ends 252 and 282 may also contact each other.

[0107] The positive current collector 402 electrically connects the positive terminal 302 to the positive electrode tab group 250 and the positive electrode tab group 280. In this embodiment, the positive current collector 402 is connected to the positive terminal 302 between the electrode body 200 and the sealing plate 130.

[0108] The positive current collector 402 includes a current collector 420 (first current collector component) and a current collector 450 (second current collector component). As an insulating component, a plate 460 is located between the current collector 420 (first current collector component) and the current collector 450 (second current collector component). The current collectors 420 and 450 are electrically connected in a cross-section different from the one shown in the figure.

[0109] The current collector 420 is a plate-shaped component. The current collector 420 has a long side in the Z direction and a short side in the Y direction. The current collector 420 is constructed from a single, integral component.

[0110] Positive electrode tabs 250 and 280 are joined to a current collector 420 consisting of a single component at a first joint 421. The first joint 421 can be formed by, for example, ultrasonic welding, resistance welding, laser welding, riveting, etc. In this embodiment, the positive electrode tabs 250 and 280 are joined to the current collector 420 by, for example, ultrasonic welding.

[0111] Current collector 440 is electrically connected to current collector 420. Current collector 440 is connected to positive terminal 302 at second joint 441. The connection between current collector 440 and positive terminal 302 can be formed, for example, by riveting and / or welding.

[0112] The positive terminal 302 is positioned to protrude on the outer side of the sealing plate 130 and reach the current collector 440 of the positive current collector 402 disposed on the inner surface side of the sealing plate 130. The positive terminal 302 is connected to the plate-shaped member 304.

[0113] The plate-shaped component 304 is located on the outside of the sealing plate 130. The plate-shaped component 304 is configured along the sealing plate 130. The plate-shaped component 304 is conductive. The plate-shaped component 304 is configured to ensure the connection area, etc., with the busbar that electrically connects the secondary battery 1 and other adjacent secondary batteries. The connection between the positive terminal 302 and the plate-shaped component 304 can be formed, for example, by laser welding.

[0114] An insulating component 510 is disposed between the plate-shaped component 304 and the sealing plate 130. An insulating component 520 is disposed between the positive terminal 302 and the sealing plate 130. An insulating component 470 is disposed between the current collector 440 and the sealing plate 130.

[0115] However, the positive terminal 302 can also be electrically connected to the sealing plate 130. In addition, the sealing plate 130 can also function as the positive terminal 302.

[0116] (Manufacturing process of secondary battery 1)

[0117] The manufacturing method of the secondary battery according to this embodiment will be described below. Figure 13 This is a flowchart illustrating a method for manufacturing a secondary battery according to one embodiment.

[0118] like Figure 13As shown, in the manufacturing method of the secondary battery in this embodiment, firstly, a first electrode body 201 and a second electrode body 202 are manufactured (S1 step). Preferably, a portion of the front end of each of the negative electrode tab group 220, positive electrode tab group 250, negative electrode tab group 270, and positive electrode tab group 280 is cut off so that the length of the front end is the same when bundled.

[0119] Next, the negative electrode tab group 220 is connected to a current collector 410 (step S2). Then, the negative electrode tab group 270 is connected to the other current collectors 410 (step S3). The negative electrode tab groups 220 and 270 are connected to the current collectors 410 at the first connection portion 411.

[0120] Next, the positive electrode tabs 250 and 280 are joined to the current collector 420 (S4 process). The positive electrode tabs 250 and 280 are joined to the current collector 420 at the first joint 421.

[0121] The order in which the first electrode 201 and the second electrode 202 are respectively connected to the current collector 410 and the current collector 420 is not limited to the above order, and the order can be changed.

[0122] Next, in the thickness direction (Y direction) of the housing body 110, the positive electrode tab group 250 and the positive electrode tab group 280 are bent so that the first electrode body 201 and the second electrode body 202 are stacked (S5 process).

[0123] The first electrode 201 and the second electrode 202 can be directly stacked, or other components can be arranged between the first electrode 201 and the second electrode 202. Furthermore, the first electrode 201 and the second electrode 202 can be fixed with tape or the like, or they can be left unfixed.

[0124] Next, one current collector 410 and other current collectors 410 are electrically connected to the negative terminal 301 via current collector 430 (step S7). It should be noted that step S7 can also be performed before step S6.

[0125] Next, after stacking the first electrode body 201 and the second electrode body 202, insert the first electrode body 201 and the second electrode body 202 into the housing body 110 through the opening 113 with the current collector 420 side as the front end (S8 process).

[0126] Next, the current collector 420 is electrically connected to the positive terminal 302 (step S9). Then, the sealing plate 120 and sealing plate 130 are joined to the housing body 110 (step S10). Thus, the first electrode 201 and the second electrode 202 are housed in the housing 100.

[0127] After the above steps, leak checks and other inspections are performed (step S11). After the leak check, the secondary battery 1 is dried to remove moisture from the casing 100. Then, electrolyte is injected into the interior of the casing 100 through the injection port 130A. After that, venting and charging are performed. During venting and charging, the injection port 130A can also be temporarily sealed. After that, the injection port 130A is sealed, and the secondary battery 1 is completed.

[0128] (The configuration of the first joints 411, 421 and the second joints 431, 441)

[0129] Figure 14 This is a diagram schematically showing an example of the configuration of the first joints 411, 421 and the second joints 431, 441 in the secondary battery 1.

[0130] like Figure 14 As shown, the electrode body 200, the current collector 400, and the electrolyte 900 are housed inside the housing 100. Electrode terminals 300 are provided on the outer surface of the housing 100.

[0131] The outer surface of the housing 100 includes: sealing plates 120, 130 (first surface) extending along a YZ plane including the Z direction (first direction); and a bottom surface 112A (second surface) connected to one end of the sealing plates 120, 130 in the Z direction and substantially orthogonal to the sealing plates 120, 130.

[0132] exist Figure 14 In the example, the first joints 411 and 421 that join the electrode body 200 and the current collector 400 are biased toward the bottom part 112A side in the Z direction. Similarly, the second joints 431 and 441 that join the current collector 400 and the electrode terminal 300 are biased toward the bottom part 112A side in the Z direction.

[0133] More specifically, the first joints 411, 421 and the second joints 431, 441 are located at the center in the height direction of the housing 100. Figure 14 The area of ​​O1 on the bottom surface 112A side.

[0134] The first joints 411 and 421, and the second joints 431 and 441 are formed by joining portions of multiple conductive components through welding, riveting, or other methods. Therefore, the electrical conductivity area at the first joints 411 and 421, and the second joints 431 and 441 tends to be relatively smaller compared to other portions. Consequently, the temperature of the electrode body 200 tends to rise near the first joints 411 and 421, and the second joints 431 and 441.

[0135] When the temperature of the electrode body 200 rises excessively, the electrolyte 900 vaporizes, and the internal pressure of the housing 100 increases. When the internal pressure of the housing 100 reaches a specified value or higher, the gas discharge valve 150 cracks. At this time, it is required that the gas discharge valve 150 cracks reliably without causing any parts other than the gas discharge valve 150 to crack.

[0136] In the secondary battery 1 of this embodiment, since the first joints 411, 421 and the second joints 431, 441 are biased towards the bottom part 112A, the first joints 411, 421 and the second joints 431, 441 are located close to the gas discharge valve 150. Therefore, the part of the electrode body 200 that is prone to temperature rise is close to the gas discharge valve 150, thus suppressing cracking at unexpected locations when the temperature rises.

[0137] When the secondary battery 1 is modularized, the first side portion 111 of the housing body 110 contacts the first side portion 111 of the adjacent secondary battery 1, thus making it difficult for bulging to occur. Therefore, the load caused by the increase in air pressure tends to concentrate on the sealing plates 120, 130 and the second side portion 112 (bottom portion 112A and upper surface portion 112B) of the housing body 110. From the viewpoint of reliably suppressing cracking of the sealing plates 120, 130 (first side), it is preferable that the thickness of the sealing plates 120, 130 (first plate-like portion) is greater than the thickness of the housing body 110 (second plate-like portion) constituting the bottom portion 112A (second side) (more preferably about three times the thickness of the housing body 110). However, the scope of this technology is not limited to this.

[0138] In Figure 14 When the secondary battery 1 shown is mounted in a vehicle, it can be mounted with the bottom portion 112A of the casing 100 facing downwards. By positioning the bottom portion 112A, where the gas vent valve 150 is formed, downwards, the electrolyte 900 can be preferentially discharged from the ruptured gas vent valve 150. Therefore, the increase in internal pressure caused by the vaporization of the electrolyte 900 can be effectively suppressed. However, the mounting structure of the secondary battery 1 in this technology is not limited to this.

[0139] More specifically, when the overall height of the housing 100 (the distance from the bottom portion 112A to the upper surface portion 112B) is set to H, the first joint portions 411, 421 and the second joint portions 431, 441 are preferably formed in a region where the distance from the bottom portion 112A is more than 1 / 10H and less than 4 / 10H. However, the scope of this technology is not limited thereto.

[0140] exist Figure 14In the secondary battery 1 shown, the electrode body 200 is a stacked electrode body, and the separator 800 is configured to protrude in the Z direction from the negative electrode plate 210 and the positive electrode plate 240 toward the bottom portion 112A (second surface) and the upper surface portion 112B (third surface). The amount of protrusion of the separator 800 in the Z direction relative to the negative electrode plate 210 and the positive electrode plate 240 is greater on the bottom portion 112A side than on the upper surface portion 112B side.

[0141] By making the diaphragm 800 protrude beyond the negative electrode plate 210 and the positive electrode plate 240, a flow path for the electrolyte 900 can be formed among the multiple diaphragms 800. By making the diaphragm 800 protrude relatively large on the bottom surface 112A side, a larger flow path area for the electrolyte 900 can be ensured on the bottom surface 112A side, improving the fluidity of the electrolyte 900. Therefore, the electrolyte 900 can be easily discharged from the gas discharge valve 150. By accelerating the discharge of the electrolyte 900, the rise in internal pressure of the casing 100 can be effectively suppressed. However, the scope of this technology is not limited to this.

[0142] exist Figure 14 In the diagram, the first joints 411 and 421 and the second joints 431 and 441 are shown to be located at the center in the height direction of the housing 100. Figure 14 The example of O1) is the area on the bottom surface 112A side, but the scope of this technology is not limited to this. It also includes the following cases: a portion of the first joint 411, 421 and the second joint 431, 441 are located on the upper surface 112B side, but more than half of the first joint 411, 421 and the second joint 431, 441 (projected area projected onto the sealing plate 120, 130) (preferably more than 60%, more preferably more than 70%, and even more preferably more than 80% or more than 90%) are located on the bottom surface 112A side.

[0143] exist Figure 14 The example shown is an example in which both the first joints 411, 421 and the second joints 431, 441 are biased toward the bottom part 112A side, but the scope of the present technology is not limited to this, and also includes the case in which only one of the first joints 411, 421 and the second joints 431, 441 is biased toward the bottom part 112A side.

[0144] exist Figure 14 The diagram shows an example where the first joints 411, 421 and the second joints 431, 441 are biased toward the bottom part 112A side on both the negative and positive sides. However, the scope of this technology is not limited to this, and also includes cases where at least one of the first joints 411, 421 and the second joints 431, 441 on either the negative or positive side is biased toward the bottom part 112A side.

[0145] In addition, in this embodiment, an example is shown where the negative electrode tabs 220, 270 and the positive electrode tabs 250, 280 are connected to the current collector 400, but the scope of this technology is not limited thereto, and an electrode body without tabs may also be used.

[0146] Figure 15 This is a perspective view showing an example of the first joint 411. Figure 15 In this example, the first joint 411 is formed by welding. In one example, the conductive area of ​​the first joint 411 (welded portion) is greater than the conductive area of ​​the current collector 410. Figure 15 It is about 0.3 times smaller than the area of ​​the cross section 410S.

[0147] Figure 16 This is a perspective view showing an example of the second joint 431. Figure 17 yes Figure 16 Sectional view of XVII-XVII. In Figure 16 , Figure 17 In this example, the second joint 431 is formed by circumferential welding. In one example, the conductive area at the second joint 431 (welded portion) is larger than the conductive area of ​​the current collector 430. Figure 16 It is about 0.2 times smaller than the area of ​​the cross section 430S in the middle.

[0148] exist Figures 15 to 17 The example shown has a fixed cross-sectional area for current collectors 410 and 430, but there are also cases where the cross-sectional area of ​​current collectors 410 and 430 varies in the length direction. In this case, the minimum value of the cross-sectional area of ​​current collectors 410 and 430 in the portion other than the first joint 411 and the second joint 431 in the cross-sectional area that varies in the length direction is called the "conducting area of ​​current collectors 410 and 430".

[0149] like Figures 15 to 17 As in the example, when the conductive areas of the first junction 411 and the second junction 431 are smaller than the conductive areas of the current collectors 410 and 430, the temperature of the electrode body 200 tends to rise around the first junction 411 and the second junction 431. In the secondary battery 1 of this embodiment, since the first junction 411 and the second junction 431 are formed near the gas discharge valve 150, the gas discharge valve 150 can be reliably opened when the temperature of the electrode body 200 rises.

[0150] However, the scope of this technology is not limited to Figures 15 to 17 The example is shown.

[0151] According to the battery of this embodiment, by biasing at least one of the first joint and the second joint toward the second surface side in a first direction, at least one of the first joint and the second joint can be brought close to the gas discharge valve. At the first joint and the second joint, the conductive area tends to decrease, and the temperature of the electrode body located nearby tends to rise. According to this technology, since the portion of the electrode body where the temperature tends to rise is close to the gas discharge valve, cracking at unexpected locations during temperature rise can be suppressed, and a highly reliable battery can be provided.

[0152] According to the battery mounting structure of this embodiment, by positioning the second surface with the gas vent valve on the lower side, electrolyte can be preferentially discharged from the ruptured gas vent valve. As a result, the increase in internal pressure caused by electrolyte vaporization can be effectively suppressed, further improving battery reliability.

[0153] Embodiments of the invention have been described, but the embodiments disclosed herein should be understood as illustrative rather than restrictive 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 battery comprising an electrode body and a housing for receiving the electrode body, wherein, The housing has an outer surface and a gas discharge valve. The outer surface includes a first surface and a second surface. The first surface extends along a plane including a first direction. The second surface is connected to one end of the first surface in the first direction and is substantially orthogonal to the first surface. The gas discharge valve is disposed on the second surface. The battery also features: Electrode terminals, the electrode terminals being disposed on the outer side of the first surface of the housing; and A current collector, wherein the current collector is disposed on the inner side of the first surface of the housing. The electrode body and the current collector are joined at the first joint. The current collector and the electrode terminal are joined at the second junction. At least one of the first joint and the second joint is biased toward the second face side in the first direction.

2. The battery as claimed in claim 1, wherein, The gas discharge valve is located only at a central position on the second surface in a second direction that is approximately orthogonal to the first surface.

3. The battery as claimed in claim 1, wherein, The electrode body has a main body and an electrode tab that protrudes from the main body toward the first surface at an end in a second direction substantially orthogonal to the first surface. The first junction is formed between the tab and the current collector.

4. The battery as claimed in claim 3, wherein, The first joint is formed by laser welding.

5. The battery as claimed in claim 3 or 4, wherein, The second joint is formed by riveting.

6. The battery as claimed in any one of claims 1 to 4, wherein, The electrode body includes a positive electrode, a negative electrode stacked on the positive electrode, and a diaphragm disposed between the positive electrode and the negative electrode.

7. The battery as claimed in claim 6, wherein, The outer surface of the housing further includes a third surface, which is connected to the other end of the first surface in the first direction and faces the second surface in the first direction. The diaphragm is configured to protrude from the positive electrode and the negative electrode toward the second surface and the third surface in the first direction. The amount by which the diaphragm protrudes relative to the positive and negative electrodes in the first direction is greater on the second side than on the third side.

8. The battery as claimed in any one of claims 1 to 4, wherein, The outer surface of the housing further includes a third surface, which is connected to the other end of the first surface in the first direction and faces the second surface in the first direction. When the distance between the second surface and the third surface in the first direction is set to H, the first joint is formed in a region in the first direction where the distance from the second surface is more than 1 / 10H and less than 4 / 10H.

9. The battery as claimed in any one of claims 1 to 4, wherein, The conductive area at the first junction is 0.3 times smaller than the conductive area of ​​the current collector.

10. The battery according to any one of claims 1 to 4, wherein, The conductive area at the second junction is 0.2 times smaller than the conductive area of ​​the current collector.

11. The battery as claimed in any one of claims 1 to 4, wherein, In the housing, the thickness of the first plate-shaped portion constituting the first surface is three times greater than the thickness of the second plate-shaped portion constituting the second surface.

12. A battery mounting structure, which is the battery mounting structure according to any one of claims 1 to 4, wherein, The second side of the housing is disposed on the bottom.

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