Battery, method for manufacturing electrode plate, and method for manufacturing battery

Abstract

Provided is a battery, a method for manufacturing an electrode plate, and a method for manufacturing a battery, which suppresses bending of electrode tabs, homogenizes the thickness of a group of electrode tabs, and stably joins the electrode tabs to a current collecting portion. A battery disclosed herein is a battery including a positive electrode plate including a positive electrode core and a positive electrode active material layer disposed on the positive electrode core, and a negative electrode plate including a negative electrode core and a negative electrode active material layer disposed on the negative electrode core. At least one of the positive electrode plate and the negative electrode plate has a plurality of electrode tabs that protrude from a region of the electrode core in which the electrode active material layer is not disposed toward the outside. The electrode tabs have an arc-shaped fold.

Description

Technical Field

[0001] This invention relates to batteries. It also relates to methods for manufacturing electrode plates and batteries. Background Technology

[0002] Batteries such as lithium-ion secondary batteries have, for example, electrode bodies with a positive electrode plate and a negative electrode plate facing each other across a separator. Hereinafter, these positive and negative electrode plates will be collectively referred to as "electrode plates." This electrode plate, for example, has an electrode active material layer forming region on an electrode core, which is a foil-shaped metal component, where an electrode active material layer containing electrode active material is formed, and an electrode core exposed region where the electrode active material layer is not formed and the electrode core is exposed. Patent Document 1 discloses an electrode plate having multiple folds extending from the boundary between the electrode active material layer forming region and the electrode core exposed region.

[0003] The electrode body has electrode tabs at both ends along its long side, and these electrode tabs are stacked together, each tab protruding outward from the exposed area of ​​the electrode core. These electrode tabs are connected to conductive components such as electrode current collectors. Furthermore, by connecting these electrode current collectors to electrode terminals, electrical conductivity is achieved between the wound electrode body inside the battery casing and the electrode terminals outside the battery casing.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: US Patent No. 8,956,754

[0007] However, in this electrode tab assembly, if multiple electrode tabs are not stacked in a flat state and have uneven thickness, it may be impossible to stably weld them to conductive components such as electrode current collectors. For example, if the electrode tabs are stacked in a bent state at their top edges, the thickness of the bent portions may be thicker, while the thickness of the flat portions may be thinner. As a result, it has been found that it may be impossible to stably perform the connection with electrode current collectors, etc. Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] The present invention was made to solve the above-mentioned problems, and its purpose is to provide a battery that suppresses the bending of each electrode tab, makes the thickness of the electrode tab assembly uniform, and thus stably connects with the electrode current collector.

[0010] Methods for solving problems

[0011] The battery disclosed herein includes a positive electrode plate comprising a positive electrode core and a positive electrode active material layer formed on the positive electrode core, and a negative electrode plate comprising a negative electrode core and a negative electrode active material layer formed on the negative electrode core. At least one of the positive and negative electrode plates has a plurality of electrode tabs protruding outward from a region in the electrode core where no electrode active material layer is formed. Arc-shaped folds are formed on the electrode tabs.

[0012] As described above, by having arc-shaped folds on the electrode tabs, bending at the tips of the electrode tabs can be appropriately suppressed. Therefore, a battery can be provided that uniformly distributes the thickness of the electrode tab assembly, thereby ensuring stable bonding between the electrode tab assembly and the electrode current collector.

[0013] In one embodiment of the battery disclosed herein, the plurality of electrode tabs are coupled to the electrode current collector in a stacked state. According to this structure, the electrode tabs are stacked while bending is suppressed, and then coupled to the electrode current collector. Therefore, a battery in which the electrode tab assembly is stably coupled to the electrode current collector can be provided.

[0014] In one embodiment of the battery disclosed herein, the arc-shaped pleats are convex at their tips facing the protruding direction of the electrode tabs. In another embodiment, the arc-shaped pleats have an asymmetrical shape in the width direction orthogonal to the protruding direction of the electrode tabs. According to this structure, bending at the tips of the electrode tabs can be more appropriately suppressed. Thus, the electrode tab assembly formed by stacking multiple electrode tabs achieves uniform thickness and engages with the electrode current collector. Therefore, a battery with stable and reliable engagement between the electrode tab assembly and the electrode current collector can be provided.

[0015] In one embodiment of the battery disclosed herein, in addition to the arc-shaped folds, multiple linear folds are formed on the electrode tabs. By forming multiple linear folds, the strength of the electrode tabs is increased, and electrode tab breakage can be appropriately suppressed. Therefore, a stable joint can be formed when the electrode tab assembly is joined to the electrode current collector, providing a battery with high reliability.

[0016] In one embodiment of the battery disclosed herein, the arc-shaped folds do not intersect with the linear folds. According to this structure, the engagement area between the electrode tab assembly and the electrode current collector can be adequately ensured, thus enabling stable engagement.

[0017] In one embodiment of the battery disclosed herein, the portion of the electrode tab that engages with the electrode current collector has the aforementioned arc-shaped folds. The area forming the arc-shaped folds becomes a relatively hard area. The arc-shaped folds at the joint ensure bonding strength.

[0018] In one embodiment of the battery disclosed herein, multiple electrode tabs of varying lengths in their protruding directions are engaged with the electrode current collector in a stacked state. According to this structure, the tips of the electrode tabs are easily aligned when multiple electrode tabs are stacked. This allows for more appropriate engagement of the electrode tab assembly with the electrode current collector.

[0019] In one embodiment of the battery disclosed herein, among a plurality of electrode tabs with varying lengths in their protruding directions, the lengths in the protruding directions from the root of the plurality of electrode tabs to the apex of the arcuate folds are approximately the same. According to this structure, the effects of the disclosed technology can be appropriately achieved even when the lengths of the protruding directions of the plurality of electrode tabs differ.

[0020] In one embodiment of the battery disclosed herein, the plurality of electrode tabs are joined to an electrode current collector in a stacked state, with the central portion of each electrode tab in the width direction being concavely bent toward the electrode current collector. According to this structure, electrode tab breakage can be suppressed when the electrode tab assembly is joined to the electrode current collector. Therefore, more appropriate joining with the electrode current collector is possible.

[0021] As another aspect of the technology disclosed herein, a method for manufacturing an electrode plate is provided. The method disclosed herein is a method for manufacturing an electrode plate having an electrode core and an electrode active material layer formed on the electrode core, comprising: a step of preparing an electrode precursor, the electrode precursor having an electrode active material layer forming region on the electrode core where the electrode active material layer is formed and an electrode core exposed region where the electrode active material layer is not formed and the electrode core is exposed; a step of processing the electrode core exposed region to create a plurality of electrode tabs protruding outward from the electrode core exposed region; and a step of forming arc-shaped folds on the electrode tabs using a roller.

[0022] According to the manufacturing method of this electrode plate, an electrode plate having the above-mentioned characteristics can be appropriately manufactured.

[0023] As another aspect of the technology disclosed herein, a method for manufacturing a battery is provided. The battery manufacturing method disclosed herein is a method for manufacturing a battery having a pair of electrode bodies facing each other with electrode plates separated by a separator, characterized in that at least one of the pair of electrode plates is manufactured using the aforementioned electrode plate manufacturing method. According to this battery manufacturing method, a battery possessing the aforementioned characteristics can be suitably manufactured. Attached Figure Description

[0024] Figure 1 This is a perspective view schematically showing one embodiment of a battery.

[0025] Figure 2 It is along Figure 1A schematic longitudinal section view of line II-II.

[0026] Figure 3 It is along Figure 1 A schematic longitudinal section view of line III-III.

[0027] Figure 4 It is along Figure 1 A schematic cross-sectional view of line IV-IV.

[0028] Figure 5 This is a schematic perspective view of the electrode assembly mounted on the sealing plate.

[0029] Figure 6 It is a perspective view schematically showing an electrode body with a positive second collector and a negative second collector installed.

[0030] Figure 7 This is a schematic diagram showing the structure of the wound electrode.

[0031] Figure 8 This is a schematic top view of the positive electrode in one implementation method.

[0032] Figure 9 It is shown schematically. Figure 8 A magnified cross-sectional view of the vicinity of the positive electrode tab.

[0033] Figure 10 It is along Figure 9 A schematic cross-sectional view of the XX line.

[0034] Figure 11 It is shown schematically. Figure 4 A magnified view of the area near the joint.

[0035] Figure 12 This is a top view illustrating the fabrication of a positive electrode plate in one embodiment.

[0036] Figure 13 This is a top view illustrating the arc-shaped fold formation process of one embodiment.

[0037] Figure 14 This is a top view illustrating the joining process of one embodiment.

[0038] Figure 15 This is a schematic cross-sectional view illustrating the battery insertion process of one embodiment.

[0039] Explanation of reference numerals in the attached figures

[0040] 10 Battery casing

[0041] 12 outer body

[0042] 14. Sealing plate (lid)

[0043] 20 electrode assembly

[0044] 20a Winded Electrode Body

[0045] 20b Winded electrode body

[0046] 20c wound electrode body

[0047] 22 Positive electrode plate

[0048] 22A surface

[0049] 22B surface

[0050] 22D positive electrode precursor

[0051] 22a Positive electrode active material layer

[0052] 22c positive electrode core

[0053] 22e end edge

[0054] 22f Positive electrode active material layer formation region

[0055] 22g exposed area of ​​positive electrode core

[0056] 22p Positive electrode protective layer

[0057] 22t positive electrode tab

[0058] 23 Positive electrode tab group

[0059] 24 Negative electrode plate

[0060] 24a Negative electrode active material layer

[0061] 24C negative electrode core

[0062] 24t negative electrode tab

[0063] 25 Negative electrode tabs

[0064] 26. Diaphragm

[0065] 27. Arc-shaped folds

[0066] 28. Linear folds

[0067] 50 Positive current collector

[0068] 51 Positive electrode first current collector

[0069] 52 Positive electrode second current collector

[0070] 53 Joint marks

[0071] 60 Negative current collector

[0072] 61 Negative electrode first collector section

[0073] 62 Negative electrode second collector section

[0074] 70 Positive electrode insulating components

[0075] 80 Negative electrode insulating component

[0076] 90 Washer

[0077] 92 External insulation components

[0078] 100 batteries

[0079] 210 Forming Roller

[0080] 212 Support Roller

[0081] 220 welding head

[0082] 222 Anvil Detailed Implementation

[0083] Hereinafter, several preferred embodiments of the technology disclosed herein will be described with reference to the accompanying drawings. It should be noted that matters necessary for the implementation of the invention, other than those specifically mentioned in this specification (e.g., the general structure and manufacturing process of the battery not representing the invention), can be understood as design matters by those skilled in the art based on prior art. The present invention can be implemented based on the content disclosed in this specification and common technical knowledge in the field. It should be noted that the expression "A to B" indicating a range in this specification includes the meaning of A and below B, and includes the meanings of "preferably greater than A" and "preferably less than B".

[0084] Furthermore, in this specification, "battery" refers to all energy storage devices capable of extracting electrical energy, encompassing both primary and secondary batteries. Additionally, in this specification, "secondary battery" refers to all energy storage devices capable of repeated charging and discharging, encompassing so-called storage batteries (chemical batteries) such as lithium-ion secondary batteries and nickel-metal hydride batteries, as well as capacitors (physical batteries) such as electric double-layer capacitors.

[0085] <Battery 100>

[0086] Figure 1 It is a 3D image of battery 100. Figure 2 It is along Figure 1 A schematic longitudinal section view of line II-II. Figure 3 It is along Figure 1 A schematic longitudinal section view of line III-III. Figure 4 It is along Figure 1A schematic cross-sectional view along line IV-IV. In the following description, the reference numerals L, R, F, Rr, U, and D in the figures represent left, right, front, back, top, and bottom, respectively, and the reference numerals X, Y, and Z in the figures represent the direction of the short side of battery 100, the direction of the long side orthogonal to the short side, and the up and down direction, respectively. However, these are merely directions for ease of explanation and do not limit the arrangement of battery 100.

[0087] like Figure 2 As shown, the battery 100 includes a battery casing 10, an electrode assembly 20, a positive terminal 30, and a negative terminal 40. Although not shown in the diagram, the battery 100 also includes an electrolyte. The battery 100 is a lithium-ion secondary battery.

[0088] The battery casing 10 is a frame that houses the electrode assembly 20. The battery casing 10 has a flat, bottomed cuboid shape (square). The material of the battery casing 10 can be the same as conventionally used materials, without particular limitation. The battery casing 10 is preferably made of metal, and more preferably of materials such as aluminum, aluminum alloy, iron, or iron alloy. Figure 2 As shown, the battery casing 10 includes: an outer body 12 with an opening 12h and a sealing plate (cover) 14 that blocks the opening 12h.

[0089] like Figure 1 As shown, the outer casing 12 includes a bottom wall 12a, a pair of long side walls 12b extending from the bottom wall 12a and facing each other, and a pair of short side walls 12c extending from the bottom wall 12a and facing each other. The bottom wall 12a is generally rectangular. The bottom wall 12a faces the opening 12h. The area of ​​the short side walls 12c is smaller than the area of ​​the long side walls 12b.

[0090] The sealing plate 14 is installed on the outer casing 12 to block the opening 12h of the outer casing 12. The sealing plate 14 faces the bottom wall 12a of the outer casing 12. The sealing plate 14 is generally rectangular in plan view. The battery housing 10 is integrated by joining (e.g., welding) the sealing plate 14 to the periphery of the opening 12h of the outer casing 12. The battery housing 10 is hermetically sealed (sealed).

[0091] like Figure 2As shown, the sealing plate 14 is provided with an injection hole 15, a gas vent valve 17, and two terminal outlet holes 18 and 19. The injection hole 15 is used to inject electrolyte after the sealing plate 14 is assembled to the outer casing 12. The injection hole 15 is sealed by a sealing member 16. The gas vent valve 17 is configured to break when the pressure inside the battery casing 10 reaches a predetermined value, thereby venting the gas inside the battery casing 10 to the outside. The terminal outlet holes 18 and 19 are respectively formed at both ends of the sealing plate 14 in the long side direction Y. The terminal outlet holes 18 and 19 penetrate the sealing plate 14 in the vertical direction Z. The terminal outlet holes 18 and 19 each have an inner diameter that allows the positive terminal 30 and negative terminal 40, which are installed before the sealing plate 14 (e.g., before riveting), to be inserted.

[0092] The electrolyte can be the same as before, with no particular restrictions. For example, the electrolyte may be a non-aqueous electrolyte containing a non-aqueous solvent and a supporting electrolyte. Non-aqueous solvents include carbonates such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate. Supporting electrolytes may be fluorinated lithium salts such as LiPF6. However, the electrolyte may also be integrated with the electrode assembly 20 in a solid form (solid electrolyte).

[0093] The positive terminal 30 and the negative terminal 40 are respectively fixed to the sealing plate 14. The positive terminal 30 is located on one side of the long side Y direction of the sealing plate 14. Figure 1 , Figure 2 (Left side). The negative terminal 40 is disposed on the other side of the long side direction Y of the sealing plate 14 ( Figure 1 , Figure 2 (The right side). For example Figure 1 As shown, the positive terminal 30 and the negative terminal 40 are exposed on the outer surface of the sealing plate 14. Figure 2 As shown, the positive terminal 30 and the negative terminal 40 are inserted through the terminal lead-out holes 18 and 19 and extend from the inside of the sealing plate 14 to the outside.

[0094] like Figure 2 As shown, the positive terminal 30 is located inside the outer casing 12 via the positive current collector 50 and the positive electrode plate 22 of the electrode assembly 20 (see reference). Figure 7 Electrical connection. The positive terminal 30 is insulated from the sealing plate 14 by the positive terminal insulating member 70 and the washer 90. The positive terminal 30 is preferably made of metal, more preferably of, for example, aluminum or an aluminum alloy.

[0095] The negative terminal 40 is located inside the outer casing 12 via the negative current collector 60 and the negative electrode plate 24 of the electrode assembly 20 (see reference). Figure 7Electrical connection. The negative terminal 40 is insulated from the sealing plate 14 by the negative electrode insulating member 80 and the washer 90. The negative terminal 40 is preferably made of metal, more preferably of, for example, copper or a copper alloy. The negative terminal 40 may also be configured as an integral part formed by joining two conductive members. For example, the part connected to the negative electrode current collector 60 may be made of copper or a copper alloy, and the part exposed on the outer surface of the sealing plate 14 may be made of aluminum or an aluminum alloy.

[0096] like Figure 1 As shown, plate-shaped positive electrode external conductive member 32 and negative electrode external conductive member 42 are mounted on the outer surface of the sealing plate 14. The positive electrode external conductive member 32 is electrically connected to the positive terminal 30. The negative electrode external conductive member 42 is electrically connected to the negative terminal 40. The positive electrode external conductive member 32 and negative electrode external conductive member 42 are components with busbars attached when multiple batteries 100 are electrically connected to each other. The positive electrode external conductive member 32 and negative electrode external conductive member 42 are preferably made of metal, more preferably of, for example, aluminum or an aluminum alloy. The positive electrode external conductive member 32 and negative electrode external conductive member 42 are insulated from the sealing plate 14 by an external insulating member 92. However, the positive electrode external conductive member 32 and negative electrode external conductive member 42 are not essential and may be omitted in other embodiments.

[0097] Figure 5 This is a schematic perspective view of the electrode assembly 20 mounted on the sealing plate 14. The electrode assembly 20 here has three wound electrodes 20a, 20b, and 20c. However, the number of wound electrodes disposed inside an outer casing 12 is not particularly limited; it can be two or more, or it can be one. Here, the electrode assembly 20 is held in place by an electrode holder 29 made of resin sheet (see reference 1). Figure 3 It is configured inside the outer casing 12 under the covered state.

[0098] Figure 6 This is a schematic perspective view of the wound electrode body 20a. Figure 7 This is a schematic diagram showing the structure of the wound electrode body 20a. It should be noted that the following detailed description uses the wound electrode body 20a as an example, but the wound electrode bodies 20b and 20c can also be designed with the same structure.

[0099] The wound electrode body 20a has a positive electrode plate 22, a negative electrode plate 24, and a separator 26. Here, the wound electrode body 20a is configured such that the strip-shaped positive electrode plate 22 and the strip-shaped negative electrode plate 24 are stacked with two strip-shaped separators 26 in between, and wound around a winding shaft WL. The wound electrode body 20a has a flat shape. The wound electrode body 20a is disposed inside the outer casing 12 with the winding shaft WL approximately parallel to the long side direction Y. Figure 3As shown, the wound electrode body 20a has: a pair of curved portions (R portions) 20r, which face the bottom wall 12a and the sealing plate 14 of the outer body 12; and a flat portion 20f, which connects the pair of curved portions 20r and faces the long sidewall 12b of the outer body 12. The flat portion 20f extends along the long sidewall 12b.

[0100] The separator 26 is a component that insulates the positive electrode active material layer 22a of the positive electrode plate 22 from the negative electrode active material layer 24a of the negative electrode plate 24. The separator 26 forms the outer surface of the wound electrode body 20a. As the separator 26, a porous sheet made of resin, such as polyethylene (PE) or polypropylene (PP), is preferably preferred. The separator 26 preferably has a substrate portion made of a porous sheet of resin and a heat resistance layer (HRL) formed on at least one surface of the substrate portion. The heat resistance layer is a layer containing inorganic fillers. Examples of inorganic fillers used are alumina, boehmite, aluminum hydroxide, and titanium dioxide.

[0101] like Figure 7 As shown, the positive electrode plate 22 has a positive electrode core 22c and a positive electrode active material layer 22a and a positive electrode protective layer 22p fixed on at least one surface of the positive electrode core 22c. However, the positive electrode protective layer 22p is not necessary and can be omitted in other embodiments. The positive electrode core 22c is strip-shaped. The positive electrode core 22c is made of a conductive metal such as aluminum, aluminum alloy, nickel, or stainless steel. The positive electrode core 22c is a metal foil, specifically an aluminum foil. In addition, the average thickness of the positive electrode core 22c is not particularly limited. For example, it is preferably 2μm to 30μm, more preferably 2μm to 20μm, and even more preferably 5μm to 15μm. The positive electrode plate 22 is an example of an electrode plate.

[0102] At one end of the long side Y of the positive electrode core 22c ( Figure 7 Multiple positive electrode tabs 22t are provided at the left end of the positive electrode 22. The multiple positive electrode tabs 22t are positioned towards the long side Y of the positive electrode 22. Figure 7 The positive electrode tabs 22t protrude from the left side of the diaphragm 26. Multiple positive electrode tabs 22t protrude more than the diaphragm 26 along the longitudinal direction Y. The multiple positive electrode tabs 22t are spaced apart (discontinuously) along the length of the positive electrode plate 22. However, the positive electrode tabs 22t can also be located at the other end in the longitudinal direction Y. Figure 7 The positive electrode tab 22t can be located at either end of the positive electrode core 22c, or at either end of the positive electrode core 22c along the long side Y. The positive electrode tab 22t is part of the positive electrode core 22c and is made of metal foil (aluminum foil). At least a portion of the positive electrode tab 22t is exposed above the positive electrode core 22c, without the positive electrode active material layer 22a and the positive electrode protective layer 22p. The positive electrode tab 22t is an example of an electrode tab.

[0103] like Figure 4 As shown, multiple positive electrode tabs 22t are located at one end in the long side direction Y ( Figure 4 The positive electrode tabs 22t are stacked at their left ends to form a positive electrode tab assembly 23. Multiple positive electrode tabs 22t are bent so that their outer ends are aligned. This improves the containment of the battery housing 10 and allows for miniaturization of the battery 100. The positive electrode tab assembly 23 is electrically connected to the positive terminal 30 via a positive current collector 50. Preferably, multiple positive electrode tabs 22t are bent and electrically connected to the positive terminal 30. A second positive current collector 52, described later, is attached to the positive electrode tab assembly 23.

[0104] like Figure 7 As shown, the positive electrode active material layer 22a is arranged in a strip shape along the length of the strip-shaped positive electrode core 22c. The positive electrode active material layer 22a contains a positive electrode active material (e.g., a lithium transition metal composite oxide such as a lithium nickel cobalt manganese composite oxide) capable of reversibly absorbing and releasing charge carriers. When the total solid content of the positive electrode active material layer 22a is set to 100% by mass, the positive electrode active material can account for approximately 80% by mass or more, typically 90% by mass or more, for example, 95% by mass or more. The positive electrode active material layer 22a may also contain any components other than the positive electrode active material, such as conductive materials, binders, and various additives. As a conductive material, carbon materials such as acetylene black (AB) can be used. As a binder, polyvinylidene fluoride (PVdF) can be used, for example.

[0105] like Figure 7 As shown, the positive electrode protective layer 22p is disposed at the boundary between the positive electrode core 22c and the positive electrode active material layer 22a in the long side direction Y. The positive electrode protective layer 22p is here disposed at one end of the positive electrode core 22c in the long side direction Y. Figure 7 (The left end). However, the positive electrode protective layer 22p can also be provided at both ends in the long side direction Y. The positive electrode protective layer 22p is provided in a strip shape along the positive electrode active material layer 22a. The positive electrode protective layer 22p contains inorganic filler (e.g., alumina). When the total solid content of the positive electrode protective layer 22p is set to 100% by mass, the inorganic filler can account for approximately 50% by mass or more, typically 70% by mass or more, for example, 80% by mass or more. The positive electrode protective layer 22p can contain any component other than the inorganic filler, such as conductive materials, binders, various additives, etc. The conductive materials and binders can be the same as those exemplified as materials that can be included in the positive electrode active material layer 22a.

[0106] Figure 8 This is a schematic top view of the positive electrode plate 22. Figure 9 It is shown schematically. Figure 8 A magnified view of the vicinity of the positive electrode tab 22t. Figure 10 It is along Figure 9 A schematic cross-sectional view of the XX line. In the following description, Figure 8 and Figure 9 In the attached diagram, reference numerals Y and W represent the protruding direction of the positive electrode tab 22t and the width direction orthogonal to the protruding direction of the positive electrode tab 22t, respectively. Additionally, Figure 10 Reference numeral X in the attached figures indicates the thickness direction of the positive electrode tab 22t. Furthermore, the width direction W is the same as the winding direction of the wound electrode body 20a. Reference numerals W1 and W2 indicate the beginning and end sides of the winding direction. The protruding direction Y is the same as the long side direction Y of the battery 100. The thickness direction X is the same as the short side direction X of the battery 100. Reference numeral B indicates the bending portion that is bent to form the bent portion 20r in the electrode body manufacturing process described later. Hereinafter, the positive electrode tab 22t of the positive electrode plate 22 will be used as an example for detailed explanation, but the negative electrode plate 24 (specifically, the negative electrode tab 24t described later) can also be configured with the same structure.

[0107] like Figure 8 As shown, the positive electrode plate 22 has an end edge 22e extending along the width direction W. Multiple positive electrode tabs 22t extend from the end edge 22e towards one side in the protruding direction Y. Figure 8 (Above) protrudes. Multiple positive electrode tabs 22t are present. Multiple positive electrode tabs 22t extend from the root portion connected to the end edge 22e of the positive electrode plate 22. The shape of the multiple positive electrode tabs 22t is not particularly limited. They can be polygonal shapes such as quadrilaterals and triangles, or semicircular shapes, etc. The shape of the positive electrode tabs 22t can also be, for example, a trapezoidal shape such as an isosceles trapezoid, a rectangle, a square, etc. The positive electrode tabs 22t can also be arranged in a symmetrical shape in the width direction W. The shape of the positive electrode tabs 22t is preferably trapezoidal. Therefore, it is less likely for the tabs to be bent during the electrode body manufacturing process. Moreover, current is less likely to concentrate at the root portion, which can suppress the situation where heat concentrates near the root portion or the resistance increases near the root portion during the charging and discharging of the battery 100.

[0108] The dimensions of the positive electrode tab 22t (e.g., the length Ta in the protruding direction Y and / or the tab length in the width direction W) are not particularly limited. For example, the length Ta in the protruding direction Y can be approximately 15mm to 25mm. Additionally, the length Wa on the root side of the positive electrode tab 22t can be approximately 25mm to 45mm. The length Wb on the tip side of the positive electrode tab 22t is preferably approximately 15mm to 25mm (e.g., approximately 20mm). Furthermore, if the positive electrode tab 22t is within this range of dimensions, it can have a sufficient bonding area during the bonding process, thereby increasing the bonding strength.

[0109] Additionally, the positive electrode tab 22t is located in the thickness direction X (refer to...). Figure 10The tab 22t can be flat or curved. Preferably, the central portion of the positive electrode tab 22t in the width direction W is convexly curved toward either the thickness direction X. When the positive electrode tab 22t is curved, the ratio of the length Wa of the root side of the positive electrode tab 22t to the maximum height of the convex curved portion can be about 8:1 to 10:1.

[0110] Multiple positive electrode tabs (22t) can have the same size or different dimensions. For example... Figure 8 As shown, when the lengths Ta of the protruding directions of the multiple positive electrode tabs 22t are different from each other, the deviation of the lengths Ta of the protruding directions of each positive electrode tab 22t is preferably within ±10mm, and more preferably within ±5mm.

[0111] The multiple positive electrode tabs 22t are preferably arranged one by one in the area divided by the bending portion B. That is, the number of positive electrode tabs 22t is preferably the same as the number of layers of the positive electrode plate 22 (one tab / one layer).

[0112] like Figure 8 and Figure 9 As shown, the positive electrode tab 22t has arc-shaped folds 27. Here, arc-shaped folds refer to folds formed on the positive electrode tab 22t typically by bending into a wave shape when force is applied in the width direction W, excluding folds formed by bending. By forming these arc-shaped folds on the positive electrode tab 22t, bending at the tip side in the protruding direction Y of the positive electrode tab 22t can be suppressed. For example, during transport when manufacturing the positive electrode plate 22, bending at the tip side of the positive electrode tab 22t can be suppressed. As a result, each process of manufacturing the positive electrode plate 22 can be performed while maintaining a good condition without bending the positive electrode tab 22t. In particular, the bonding process described later can be performed stably, and the bonding strength between the positive electrode tab assembly 23 and the positive current collector 50 is increased. Therefore, a battery with high bonding strength and high reliability can be provided.

[0113] The arc-shaped fold 27 can be formed in one or more (i.e., two or more) of each positive electrode tab 22t. Preferably, one arc-shaped fold 27 is formed in each positive electrode tab 22t.

[0114] In several ways, such as Figure 9As shown, the arc-shaped pleat 27 is preferably convex towards its apex in the protruding direction Y. The length of the arc of the arc-shaped pleat 27 is not particularly limited, but is preferably 10 mm or more. If the length of the arc of the arc-shaped pleat 27 is too short, the effect of suppressing the bending of the positive electrode tab 22t as described above may be reduced. The width (length of the chord of the arc) La and the maximum height (length from the apex P of the arc to the chord) Lb of the arc-shaped pleat 27 are not particularly limited. For example, it is preferable to adjust the ratio of the width La of the arc-shaped pleat 27 to the maximum height Lb of the arc-shaped pleat 27 to be approximately 2:1 to 5:1.

[0115] In several ways, such as Figure 9 As shown, the arc-shaped pleats 27 are preferably formed in a shape that is asymmetrical with respect to the width direction W of the positive electrode tab 22t. That is, preferably, the apex P of the arc-shaped pleats 27 is not on the center line Q of the length Wa in the width direction of the positive electrode tab 22t on the root side. In addition, the apex P of the arc-shaped pleats 27 is preferably formed at a position closer to the tip than the root side in the protrusion direction Y. By having such arc-shaped pleats 27, bending of the positive electrode tab 22t is more appropriately suppressed.

[0116] In several configurations, when the lengths Ta of the protruding directions of the multiple positive electrode tabs 22t differ, the length Tb of the protruding direction from the root of the positive electrode tab 22t to the apex P of the arc-shaped fold 27 is preferably approximately the same. This appropriately suppresses bending of the positive electrode tabs 22t. Furthermore, the length Tc of the protruding direction from the tip of the positive electrode tab 22t to the apex P of the arc-shaped fold 27 can be approximately the same or different. Preferably, the lengths Tc of the protruding direction are different. When the lengths Tc of the protruding directions are different, the difference can be in an amount equal to the deviation of the length Ta of the protruding direction of each positive electrode tab 22t.

[0117] like Figure 10 As shown, the arc-shaped fold 27 can be a convex or concave portion formed relative to surfaces 22A and 22B of the positive electrode tab 22t. For example, the arc-shaped fold 27 may have a convex portion protruding at a height D on the surface 22A side of the positive electrode tab 22t. This convex portion can be a convex portion protruding towards the surface 22A side of the positive electrode tab 22t, or it can be a convex portion protruding towards the surface 22B side. As described above, when the central portion of the positive electrode tab 22t in the width direction W is convexly curved towards the thickness direction X, the convex portion of the arc-shaped fold 27 can protrude in the same direction as the convex curvature of the positive electrode tab 22t.

[0118] In several ways, such as Figure 9As shown, in addition to the aforementioned arc-shaped folds 27, linear folds 28 can also be formed on the positive electrode tab 22t. These linear folds 28 extend from the root side of the positive electrode tab 22t (more specifically, the boundary between the positive electrode protective layer 22p and the positive electrode core 22c) towards the tip side of the positive electrode tab 22t. The linear folds 28 only need to be approximately straight. Furthermore, as... Figure 9 As shown, it can also be tilted relative to the protruding direction Y. By having linear wrinkles 28 in addition to arc-shaped wrinkles 27 in the positive electrode tab 22t, it is possible to suppress tab breakage of the positive electrode tab 22t.

[0119] In addition, in the case where linear folds 28 are formed in addition to arc-shaped folds 27 in the positive electrode tab 22t, it is preferable that the arc-shaped folds 27 and the linear folds 28 do not intersect each other.

[0120] Each positive electrode tab 22t may have one linear pleat 28, or multiple pleats (i.e., two or more). Preferably, each positive electrode tab 22t has multiple linear pleats 28. When multiple linear pleats 28 are formed, the linear pleats 28 may be formed with a predetermined interval relative to the width direction W and not intersect each other, or the linear pleats 28 may be formed to intersect each other. Preferably, the multiple linear pleats 28 extend in the same direction and are formed to be substantially parallel.

[0121] The length Ld of the linear pleats 28 is not particularly limited, but is preferably 2 mm or more. Furthermore, the linear pleats 28 have a recess in the thickness direction of the positive electrode tab 22t. The depth of the recess in the linear pleats 28 is preferably shallower than the depth of the recess in the arc-shaped pleats 27. Moreover, the recess can be a recess protruding towards the surface 22B side of the positive electrode tab 22t, or it can be a recess protruding towards the surface 22A side.

[0122] like Figure 7 As shown, the negative electrode plate 24 has a negative electrode core 24c and a negative electrode active material layer 24a fixed to at least one surface of the negative electrode core 24c. The negative electrode core 24c is strip-shaped. The negative electrode core 24c is made of a conductive metal such as copper, copper alloy, nickel, or stainless steel. The negative electrode core 24c is a metal foil, specifically a copper foil. The negative electrode plate 24 is an example of an electrode plate.

[0123] At one end of the long side Y of the negative electrode core 24c ( Figure 7 Multiple negative electrode tabs 24t are provided at the right end of the diaphragm 26. These multiple negative electrode tabs 24t protrude beyond the diaphragm 26 in the long side direction Y. The multiple negative electrode tabs 24t are spaced apart (discontinuously) along the length of the negative electrode plate 24. The negative electrode tabs 24t are located on one side in the long side direction Y. Figure 7 The right side protrudes. However, the negative electrode tab 24t can be located at the other end in the long side direction Y ( Figure 7 The negative electrode tab 24t can be located at either end of the negative electrode core 24c, or at either end of the negative electrode core 24c along the long side Y. The negative electrode tab 24t is part of the negative electrode core 24c and is made of metal foil (copper foil). A negative electrode active material layer 24a is formed on a portion of the negative electrode tab 24t. At least a portion of the negative electrode tab 24t does not have the negative electrode active material layer 24a formed, exposing the negative electrode core 24c. The negative electrode tab 24t is an example of an electrode tab.

[0124] like Figure 4 As shown, multiple negative electrode tabs 24t are located at one end in the long side direction Y ( Figure 6 The right ends of the electrodes are stacked to form a negative electrode tab group 25. The negative electrode tab group 25 is positioned symmetrically to the positive electrode tab group 23 in the long side direction Y. The multiple negative electrode tabs 24t are bent in such a way that their outer ends are aligned. This improves the containment of the battery housing 10 and enables the miniaturization of the battery 100. The negative electrode tab group 25 is electrically connected to the negative terminal 40 via a negative electrode current collector 60. Preferably, the multiple negative electrode tabs 24t are bent and electrically connected to the negative terminal 40. A second negative electrode current collector 62, described later, is attached to the negative electrode tab group 25.

[0125] like Figure 7 As shown, the negative electrode active material layer 24a is arranged in a strip shape along the length of the strip-shaped negative electrode core 24c. The negative electrode active material layer 24a contains a negative electrode active material (e.g., carbon materials such as graphite) capable of reversibly absorbing and releasing charge carriers. When the total solid content of the negative electrode active material layer 24a is set to 100% by mass, the negative electrode active material can account for approximately 80% by mass or more, typically 90% by mass or more, for example, 95% by mass or more. The negative electrode active material layer 24a may also contain any components other than the negative electrode active material, such as binders, dispersants, and various additives. For example, rubbers such as styrene-butadiene rubber (SBR) can be used as binders. For example, cellulose-based materials such as carboxymethyl cellulose (CMC) can be used as dispersants.

[0126] The positive current collector 50 forms a conductive path that electrically connects the positive electrode tab group 23, composed of multiple positive electrode tabs 22t, to the positive terminal 30. For example... Figure 2 and Figure 5As shown, the positive electrode current collector 50 includes: a first positive electrode current collector 51, which is a plate-shaped conductive member extending along the inner side of the sealing plate 14; and a plurality of second positive electrode current collectors 52, which are plate-shaped conductive members extending in the vertical direction Z. The lower end portion 30c of the positive terminal 30 extends toward the interior of the battery casing 10 through the terminal lead-out hole 18 of the sealing plate 14 and is connected to the first positive electrode current collector 51 (see reference). Figure 2 On the other hand, such as Figures 4-6 As shown, the second positive current collector 52 is connected to the positive electrode tabs 23 of each of the plurality of wound electrode bodies 20a, 20b, and 20c. The first positive current collector 51 and the second positive current collector 52 can also be made of the same type of metal as the positive electrode core 22c, such as conductive metals like aluminum, aluminum alloy, nickel, or stainless steel. The positive current collector 50 is an example of an electrode current collector.

[0127] The lower end 30c of the positive terminal 30 extends into the battery casing 10 through the terminal lead-out hole 18 of the sealing plate 14 and is connected to the positive first current collector 51 (see reference). Figure 2 On the other hand, such as Figures 4-6 As shown, the second positive current collector 52 is connected to the positive electrode tabs 23 of each of the plurality of wound electrode bodies 20a, 20b, and 20c. Furthermore, as... Figure 4 and Figure 5 As shown, the positive electrode tab assembly 23 of the wound electrode bodies 20a, 20b, and 20c is bent such that the second positive electrode current collector 52 faces one side 20e of the wound electrode bodies 20a, 20b, and 20c. Thus, the upper end of the second positive electrode current collector 52 is electrically connected to the first positive electrode current collector 51.

[0128] In a positive electrode tab assembly 23 with multiple positive electrode tabs 22t stacked on top of each other, it is preferable that the aforementioned arc-shaped folds 27 are formed at different positions in each positive electrode tab 22t. The area where the arc-shaped folds 27 are formed is relatively hard and has higher strength. Therefore, the location of such arc-shaped folds 27 is different in each positive electrode tab 22t in the positive electrode tab assembly 23, thereby improving the overall strength of the positive electrode tab assembly 23.

[0129] As described above, in the positive electrode tab 22t, oriented towards the thickness direction X (refer to...) Figure 10When the positive electrode tab 22t is convexly bent, the protruding direction of the convex portion of each positive electrode tab 22t in the multiple stacked positive electrode tab groups 23 can be the same. Therefore, when bending with the positive electrode second current collector 52 facing one side 20e of the wound electrode bodies 20a, 20b, 20c, bending is easy. Furthermore, when the positive electrode tab 22t is convexly bent in the width direction W towards the thickness direction X, it is preferable to be convexly bent away from the positive electrode second current collector 52 (i.e., concavely bent towards the positive electrode second current collector 52). This helps to suppress breakage of the positive electrode tab 22t in the bonding process described later, forming a suitable joint. Moreover, although not particularly limited, when the positive electrode tab 22t is convexly bent in the width direction W towards the thickness direction X, it is preferable to be convexly bent radially outward towards the wound electrode body 20a. Therefore, in the electrode manufacturing process described later, the wound electrode 20a can be manufactured more appropriately.

[0130] The second positive current collector 52 is a portion attached to the positive electrode tab group 23 and electrically connected to the plurality of positive electrode tabs 22t, as described above. Figure 4 As shown, a junction J with the positive electrode tab assembly 23 is formed in the second current collector 52 of the positive electrode. The junction J is, for example, a welded junction formed by welding multiple positive electrode tabs 22t overlapping, using ultrasonic welding, resistance welding, laser welding, or the like. This junction J may also have the aforementioned arc-shaped folds 27. Because the junction J has arc-shaped folds 27, welding can be performed appropriately while suppressing bending at the tips of the multiple positive electrode tabs 22t. Therefore, poor bonding can be more appropriately suppressed, thus improving the bonding strength of the junction J and providing a highly reliable battery 100.

[0131] Figure 11 It is shown schematically. Figure 4 An enlarged view of the vicinity of the joint J. In several ways, the positive electrode second current collector 52 is joined to the positive electrode tab assembly 23 by ultrasonic welding, resulting in a joint mark 53 at the joint J. Here, the joint mark 53 is composed of multiple recesses. Specifically, the joint mark 53 is a collection of recesses formed by the welding head of the ultrasonic welding device during ultrasonic welding. The joint mark 53 may be a shape in which the recesses on an inverted square pyramid corresponding to the shape of the tip of the welding head of the ultrasonic welding device contact and are arranged. In addition, the shape of the joint mark 53 (i.e., the overall shape of the collection of recesses) is approximately square when viewed from above (when viewed from the thickness direction of the positive electrode tab assembly 23).

[0132] When there is a joint mark 53 at the junction J between the positive electrode tab group 23 and the positive electrode second current collector 52, the joint mark 53 is preferably as follows: Figure 11As shown, it overlaps with the arc-shaped fold 27. Furthermore, in this case, it is preferable that the width La of the arc-shaped fold 27 is longer than the width Wc of the long side of the joining mark 53. Since the area where the arc-shaped fold 27 is formed is relatively hard, damage to the positive electrode tab 22t can be suppressed. On the other hand, when a linear fold 28 is formed on the positive electrode tab 22t, it is preferable that the area where the linear fold 28 is formed does not overlap with the joining mark 53.

[0133] The negative current collector 60 forms a conductive path that electrically connects the negative electrode tab group 25, composed of multiple negative electrode tabs 24t, to the negative terminal 40. The structure of the negative current collector 60 can be the same as that of the positive current collector 50. Specifically, as... Figure 2 and Figure 5 As shown, the negative electrode current collector 60 includes: a first negative electrode current collector 61, which is a plate-shaped conductive member extending along the inner side of the sealing plate 14; and a plurality of second negative electrode current collectors 62, which are plate-shaped conductive members extending along the vertical direction Z. The lower end 40c of the negative terminal 40 extends toward the interior of the battery casing 10 through the terminal lead-out hole 18 of the sealing plate 14 and is connected to the first negative electrode current collector 61 (see reference). Figure 2 On the other hand, such as Figures 4-6 As shown, the second negative current collector 62 is connected to the negative electrode tabs 25 of each of the plurality of wound electrode bodies 20a, 20b, and 20c. The first negative current collector 61 and the second negative current collector 62 can also be made of the same type of metal as the negative electrode core 24c, such as conductive metals like copper, copper alloys, nickel, and stainless steel. The negative current collector 60 is an example of an electrode current collector.

[0134] like Figure 2 As shown, a positive electrode insulating member 70 is disposed between the first positive electrode current collector 51 and the inner surface of the sealing plate 14. The positive electrode insulating member 70 is a member that insulates the sealing plate 14 from the first positive electrode current collector 51. The positive electrode insulating member 70 is made of a resin material that has resistance and electrical insulation to the electrolyte used and is elastically deformable, such as polyolefin resins such as polypropylene (PP), fluorinated resins such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), polyphenylene sulfide (PPS), etc.

[0135] The positive electrode insulating member 70 has a plate-shaped base 70a sandwiched between the positive electrode first current collector 51 and the inner surface of the sealing plate 14. This prevents the positive electrode first current collector 51 from conducting with the sealing plate 14. Furthermore, the positive electrode insulating member 70 has a protrusion 70b that protrudes from the inner surface of the sealing plate 14 toward the wound electrode bodies 20a, 20b, and 20c constituting the electrode body assembly 20 (see reference). Figure 2 and Figure 3Therefore, the movement of the winding electrode bodies 20a, 20b, and 20c in the vertical Z direction can be restricted, preventing the winding electrode bodies 20a, 20b, and 20c from directly contacting the sealing plate 14.

[0136] The number of protrusions 70b is the same as the number of wound electrode bodies 20a, 20b, and 20c constituting the electrode body assembly 20, that is, three. This allows the wound electrode bodies 20a, 20b, and 20c to face the protrusions 70b more reliably. However, the number of protrusions 70b may also differ from the number of electrode bodies constituting the electrode body assembly 20; for example, it may be one.

[0137] like Figure 2 As shown, the negative electrode insulating member 80 is symmetrically arranged with respect to the center CL of the long side direction Y of the electrode body assembly 20 and the positive electrode insulating member 70. The structure of the negative electrode insulating member 80 can be the same as that of the positive electrode insulating member 70. Here, the negative electrode insulating member 80, like the positive electrode insulating member 70, has a base 80a and a plurality of protrusions 80b disposed between the sealing plate 14 and the negative electrode first current collector 61.

[0138] <Method for manufacturing electrode plates>

[0139] As described above, in the battery 100 of this embodiment, arc-shaped folds 27 are formed on the positive electrode tabs 22t and / or negative electrode tabs 24t of the positive electrode plate 22 and / or negative electrode plate 24. By forming such arc-shaped folds 27, bending at the top end of the protruding direction Y of the electrode tabs can be suppressed, and the thickness of the positive electrode tab group 23 and / or negative electrode tab group 25 can be made uniform. In addition, by forming arc-shaped folds 27, the bonding strength between the electrode tab group and the electrode current collector is increased, and a stable bonding portion J can be formed. Hereinafter, an example of a method for manufacturing an electrode plate having positive electrode tabs 22t and / or negative electrode tabs 24t with arc-shaped folds 27 as described above will be described. The method for manufacturing an electrode plate in this embodiment includes an electrode preparation step, an electrode tab fabrication step, and an arc-shaped fold formation step. It should be noted that the manufacturing method disclosed herein may further include other steps at any stage. Furthermore, the manufacturing method of the positive electrode plate 22 will be described in detail below as an example, but the negative electrode plate 24 can also be manufactured using the same method.

[0140] In the electrode preparation process, a positive electrode precursor 22D is prepared as the precursor to the positive electrode plate 22. For example... Figure 12As shown, the positive electrode precursor 22D includes a positive electrode core 22c, which is a strip-shaped metal foil. The positive electrode precursor 22D is an example of an electrode precursor. The area of ​​the positive electrode core 22c of the positive electrode precursor 22D is larger than the area of ​​the positive electrode plate 22 (i.e., the manufactured positive electrode plate 22). A positive electrode active material layer 22a and a positive electrode protective layer 22p are formed on the surface of the positive electrode core 22c. However, the positive electrode protective layer 22p is not necessary and can be omitted in other embodiments. When viewed from above, the positive electrode plate 22 has a positive electrode active material layer forming region 22f where the positive electrode active material layer 22a and the positive electrode protective layer 22p are formed, and a positive electrode core exposed region 22g where the positive electrode active material layer 22a and the positive electrode protective layer 22p are not formed and the positive electrode core 22c is exposed. The positive electrode active material layer forming region 22f is an example of an electrode active material layer forming region. In addition, the exposed area 22g of the positive electrode core is an example of the exposed area of ​​the electrode core.

[0141] There is no particular limitation on the method for preparing the positive electrode precursor 22D with the above structure, and various conventionally known methods can be used without particular restriction. For example, positive electrode paste, which serves as a precursor material for the positive electrode active material layer 22a, and protective paste, which serves as a precursor material for the positive electrode protective layer 22p, are coated on the surface (both sides) of the strip-shaped positive electrode core 22c, and each paste is dried, thereby producing the positive electrode precursor 22D.

[0142] The aforementioned linear wrinkles 28 can be formed during the electrode preparation process. Specifically, linear wrinkles 28 can be formed by applying various pastes to the positive electrode core 22c, allowing them to dry, and then performing a stamping process. The stamping method is not particularly limited; for example, a flatbed press or a roller press can be used. It is preferable to perform the stamping using a roller press. By adjusting the stamping pressure and conveying speed of the roller press, appropriate linear wrinkles 28 can be formed near the region where the electrode active material layer is formed.

[0143] Next, in the electrode tab manufacturing process, the positive electrode plate 22 is cut out from the positive electrode precursor 22D to manufacture the positive electrode tab 22t. Figure 12 This diagram schematically illustrates the fabrication of the positive electrode plate 22. In the electrode tab fabrication process, for example, it is preferable to use a laser to cut the region (protective layer forming region) of the positive electrode precursor 22D where the positive electrode protective layer 22p is formed. At this time, as... Figure 12 The dashed line L in P1As shown, a laser is scanned along the protruding direction Y of the positive electrode precursor 22D, moving from the positive electrode active material layer formation region 22f toward the positive electrode core exposure region 22g. Then, after scanning a certain distance along the width direction W of the positive electrode precursor 22D, the laser is again scanned along the protruding direction Y, moving toward the positive electrode active material layer formation region 22f. As a result, a portion of the positive electrode core exposure region 22g is cut into a convex shape to form a positive electrode tab 22t (see reference). Figure 8 It should be noted that, in the cutting of the positive electrode plate 22, in addition to using a laser for cutting, cutting blades, molds, knives, etc. can also be used.

[0144] According to the inventors' understanding, the longer the width direction W of the positive electrode tab 22t, the more appropriately the aforementioned arc-shaped folds 27 can be formed. Therefore, the width direction length Wa of the root side of the positive electrode tab 22t is preferably 25 mm or more, and the width direction length Wb of the tip side of the positive electrode tab 22t is preferably 15 mm or more. Furthermore, the length of the protrusion direction Y of the positive electrode tab 22t is preferably, for example, 15 to 25 mm, more preferably 17 to 23 mm. In the electrode tab manufacturing process, it can be cut in a manner similar to manufacturing a positive electrode tab 22t of this shape.

[0145] Alternatively, the positive electrode plate 22 may have multiple positive electrode tabs 22t, each with a different length in the protruding direction Y (see reference). Figure 8 When the lengths of the protruding direction Y in the plurality of positive electrode tabs 22t are different, for example, the deviation of the length of the protruding direction Y is preferably within ±10 mm, more preferably within ±5 mm. In the electrode tab manufacturing process, by cutting the plurality of positive electrode tabs 22t into this shape, the top end of the positive electrode tab assembly 23 manufactured in the electrode body manufacturing process described later becomes easier to align.

[0146] In the arc-shaped fold formation process, arc-shaped folds 27 are formed on the positive electrode tab 22t fabricated above. Figure 13 This diagram schematically illustrates the process of forming arc-shaped folds. In the process of forming arc-shaped folds, as... Figure 13As shown, the positive electrode plate 22, which has been fabricated to produce the positive electrode tab 22t, is conveyed by the support roller 212 along the conveying direction indicated by the arrow, and an arc-shaped pleat 27 is formed by the forming roller 210. As described above, the arc-shaped pleat 27 is preferably asymmetrical in the width direction W of the positive electrode tab 22t. Furthermore, the apex P of the arc-shaped pleat 27 is preferably closer to the top end than the root side in the protrusion direction Y. By forming such an arc-shaped pleat 27 in the positive electrode tab 22t, bending of the positive electrode tab 22t during conveying of the positive electrode plate 22 can be suppressed, for example. This arc-shaped pleat 27 can be controlled, for example, by appropriately adjusting the shape of the positive electrode tab 22t (length in the width direction W and length in the protrusion direction Y) and the shape of the forming roller 210 (roller diameter and wrap angle θ). Additionally, as... Figure 13 As shown, the wrap angle θ refers to the angle of the arc portion of the forming roller 210 that contacts the positive electrode plate 22.

[0147] While not specifically limited, it is presumed that when in contact with the forming roller 210, there is a difference in pressure applied from the forming roller 210 on the upstream and downstream sides of the conveying direction of the positive electrode tab 22t, thereby forming arc-shaped folds 27. For example, the smaller the diameter of the forming roller 210, the more suitable the arc-shaped folds 27 can be formed. The diameter of the forming roller 210 is preferably, for example, Φ35mm or less. The lower limit of the diameter of the forming roller 210 is not particularly limited, for example, Φ20mm or more. In a preferred embodiment, the maximum length of the width direction W of the positive electrode tab 22t (here, the length Wa in the width direction on the root side) and the diameter of the forming roller 210 are adjusted so that the positive electrode tab 22t does not completely follow the outer peripheral surface of the forming roller 210. In addition, the arc-shaped folds 27 can be appropriately formed, for example, by adjusting the wrap angle θ of the forming roller 210 between 105° and 175°. By using the forming roller 210 as described above, it is possible to form arc-shaped pleats 27 of the desired shape.

[0148] The positive electrode tab 22t is preferably formed to be bent in the thickness direction X as it passes between the support roller 212 and the forming roller 210. Typically, the positive electrode tab 22t is shaped along the outer peripheral surface of the forming roller 210 and can be bent in a convex manner toward the support roller 212. By bending the positive electrode tab 22t in the thickness direction, the positive electrode tab 22t is less likely to break during the bonding process described later, and the bonding strength is increased. In addition, the protrusion of the arc-shaped pleat 27 can be formed to protrude in the same direction as the convex bending direction of the positive electrode tab 22t.

[0149] According to the above-described electrode plate manufacturing method, arc-shaped folds 27 can be appropriately formed on the electrode tabs. This helps to suppress bending at the tip of the electrode tabs.

[0150] <Battery Manufacturing Method>

[0151] The method for manufacturing the battery 100 disclosed herein uses a positive electrode plate 22 and / or a negative electrode plate 24 to characterize the electrode plates manufactured by the method described above. Other manufacturing processes can be the same as conventional methods. In addition to the positive electrode plate 22 and / or negative electrode plate 24 described above, the battery 100 also includes a separator 26, a battery casing 10 (outer body 12 and sealing plate 14), an electrolyte, a positive terminal 30, a negative terminal 40, a positive current collector 50 (a first positive current collector 51 and a second positive current collector 52), and a negative current collector 60 (a first negative current collector 61 and a second negative current collector 62), and is manufactured by a method that sequentially includes, for example, an electrode body fabrication process, a terminal mounting process, a bonding process, an insertion process, and a sealing process. Furthermore, the manufacturing method disclosed herein may further include other processes at any stage.

[0152] In the electrode body fabrication process, an electrode body comprising a positive electrode plate 22, a negative electrode plate 24, and a separator 26 is fabricated. It should be noted that at least one of the positive electrode plate 22 and the negative electrode plate 24 is an electrode plate manufactured using the manufacturing method described above. In the electrode body fabrication process, a wound electrode body 20a is fabricated by winding the strip-shaped positive electrode plate 22 and the strip-shaped negative electrode plate 24 with the strip-shaped separator 26 in between. Specifically, a laminated body is fabricated by stacking the separator 26, the negative electrode plate 24, the separator 26, and the positive electrode plate 22 in this order (see reference). Figure 7 Then, the laminated body is wound in such a manner that multiple positive electrode tabs 22t are stacked at the same position on one side edge in the short-side direction and multiple negative electrode tabs 24t are stacked at the corresponding position on the other side edge. Thus, a structure is fabricated as follows: Figure 7 The electrode body 20a is wound as shown. In this case, the electrode tabs (positive electrode tab 22t and / or negative electrode tab 24t) are preferably wound in the same direction as the protruding direction when the central portion in the width direction W is convexly bent toward the thickness direction as described above.

[0153] In the terminal installation process, the positive terminal 30, the positive first current collector 51, the positive insulating member 70, the negative terminal 40, the negative first current collector 61, and the negative insulating member 80 are installed on the sealing plate 14. It should be noted that the manufacturing method of the first assembly can be any conventionally known method without particular limitation, and is not limited to the technology disclosed herein; therefore, detailed descriptions are omitted. For example, the positive terminal 30 (or negative terminal 40), the positive first current collector 51 (or negative first current collector 61), and the positive insulating member 70 (or negative insulating member 80) can be fixed to the sealing plate 14 by riveting.

[0154] In the joining process, such as Figure 4As shown, with the multiple positive electrode tabs 22t bent, the first positive electrode current collector 51 fixed to the sealing plate 14 is joined to the second positive electrode current collector 52 of the wound electrode bodies 20a, 20b, and 20c, respectively. For example, in the joining of the positive electrode tab group 23 and the second positive electrode current collector 52, ultrasonic joining (also known as ultrasonic welding) can preferably be used.

[0155] Figure 14 This diagram schematically illustrates a bonding process based on ultrasonic bonding. (For example...) Figure 14 As shown, a process is performed in which the welding head 220 and the anvil 222 of the ultrasonic bonding apparatus clamp the positive electrode tab assembly 23 and the positive electrode second current collector 52. Here, the positive electrode tab assembly 23 is in contact with the welding head 220, and the positive electrode second current collector 52 is in contact with the anvil 222. Then, while pressing the welding head 220 towards the anvil 222, the welding head 220 is vibrated to perform ultrasonic bonding of the positive electrode tab assembly 23 and the positive electrode second current collector 52. The ultrasonic bonding method can be performed in the same manner as known methods.

[0156] The tip of the welding head 220 used here has multiple protrusions. The shape of the tip of the welding head 220 is not particularly limited; for example, it can be a shape with multiple square pyramids arranged in a row. As described above, the joint mark 53 is a collection of recesses formed by the welding head 220 during ultrasonic welding.

[0157] At this point, the welding head 220 and anvil 222 are used to clamp the portion of the positive electrode tab 22t with the arc-shaped folds 27. Since the portion with the arc-shaped folds 27 is relatively hard, the positive electrode tab 22t is less likely to break, allowing for more appropriate ultrasonic bonding. Furthermore, when the central portion of the positive electrode tab 22t in the width direction W is convexly bent towards the thickness direction X as described above, the convex bending directions of each positive electrode tab 22t are aligned and stacked, as follows: Figure 14 As shown, the electrode tabs are arranged and joined in a convex bend towards the welding head 220. This prevents the positive electrode tab 22t from breaking, resulting in a more stable connection and increased joint strength. Similarly, ultrasonic bonding is performed on the negative electrode plate 24 side using the same method. Furthermore, ultrasonic bonding has been described as an example of the method for joining the electrode tab assembly and the electrode current collector, but this method is not particularly limited. For example, ultrasonic welding, resistance welding, laser welding, etc., can also be used.

[0158] During the insertion process, the electrode assembly 20, which is integrated with the sealing plate 14, is housed in the internal space of the outer casing 12. Figure 15This is a schematic cross-sectional view illustrating the insertion process. Specifically, firstly, an insulating resin sheet made of a resin material such as polyethylene (PE) is bent into a bag or box shape to prepare an electrode holder 29. Next, the electrode assembly 20 is housed in the electrode holder 29. Then, the electrode assembly 20, covered by the electrode holder 29, is inserted into the outer casing 12. If the electrode assembly 20 is heavy, approximately 1 kg or more, for example, 1.5 kg or more, and further 2 to 3 kg, then... Figure 15 As shown, the electrode assembly 20 is inserted into the outer body 12 by arranging the long sidewall 12b of the outer body 12 in a manner that intersects with the direction of gravity (making the outer body 12 horizontal).

[0159] The bent portions 20r of the wound electrode bodies 20a, 20b, and 20c constituting the electrode body assembly 20 are pressed into the interior of the outer casing 12 by the protrusions 70b of the positive electrode insulating member 70 and / or 80b of the negative electrode insulating member 80, respectively. By pressing the electrode body assembly 20 with the protrusions 70b and / or 80b, the load on the positive electrode tab assembly 23 and / or the negative electrode tab assembly 25 can be reduced, especially the load applied near the root of the positive electrode tab 22t.

[0160] The positive electrode tab assembly 23 and / or the negative electrode tab assembly 25 have clearance that allows them to move in a direction intersecting the protruding direction (typically the vertical Z direction). Therefore, if the outer casing 12 is erected with the sealing plate 14 positioned upwards after the electrode assembly 20 is inserted into it, the electrode assembly 20 will move slightly downwards due to gravity. Thus, as... Figure 3 As shown, the protrusion 70b of the positive electrode insulating member 70 and the wound electrode bodies 20a, 20b, and 20c are positioned separately. Similarly, the protrusion 80b of the negative electrode insulating member 80 and the wound electrode bodies 20a, 20b, and 20c are also positioned separately.

[0161] In the sealing process, the sealing plate 14 is joined to the edge of the opening 12h of the outer casing 12 to seal the opening 12h. The joining of the sealing plate 14 can be performed, for example, by welding such as laser welding. Afterward, electrolyte is injected through the injection hole 15, and the injection hole 15 is blocked with the sealing member 16, thereby sealing the battery 100.

[0162] As described above, battery 100 can be manufactured.

[0163] Battery 100 can be used for various purposes, such as serving as a power source (drive power source) for motors in vehicles such as passenger cars and trucks. There are no particular limitations on the type of vehicle; examples include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs). Battery 100 can be used in the construction of battery packs.

[0164] The present invention has been described above with reference to several embodiments, but these embodiments are merely examples. The present invention can be implemented in various other ways. The present invention can be implemented based on the content disclosed in this specification and common technical knowledge in the field. The technology described in the claims includes technology obtained by various modifications and alterations to the embodiments illustrated above. For example, a portion of the above embodiments can be replaced with other modifications, and other modifications can be added to the above embodiments. Furthermore, if a technical feature is not described as an essential technical feature, it can be appropriately deleted.

Claims

1. A battery, the battery comprising a positive electrode plate and a negative electrode plate, the positive electrode plate comprising a positive electrode core and a positive electrode active material layer disposed on the positive electrode core, the negative electrode plate comprising a negative electrode core and a negative electrode active material layer disposed on the negative electrode core, wherein, At least one of the positive and negative electrode plates has a plurality of electrode tabs protruding outward from the region in the electrode core where no electrode active material layer is disposed. The electrode tabs have arc-shaped folds. In addition to the arc-shaped folds, the electrode tabs also have multiple linear folds.

2. The battery according to claim 1, wherein, The plurality of electrode tabs are engaged with the electrode current collector in a stacked state.

3. The battery according to claim 1, wherein, The arc-shaped folds do not intersect with the linear folds.

4. A battery, the battery comprising a positive electrode plate and a negative electrode plate, the positive electrode plate comprising a positive electrode core and a positive electrode active material layer disposed on the positive electrode core, the negative electrode plate comprising a negative electrode core and a negative electrode active material layer disposed on the negative electrode core, wherein, At least one of the positive and negative electrode plates has a plurality of electrode tabs protruding outward from the region in the electrode core where no electrode active material layer is disposed. The electrode tabs have arc-shaped folds. The plurality of electrode tabs are engaged with the electrode current collector in a stacked state, and the central portion of the electrode tabs in the width direction is concave and bent toward the electrode current collector.

5. A battery, the battery comprising a positive electrode plate and a negative electrode plate, the positive electrode plate comprising a positive electrode core and a positive electrode active material layer disposed on the positive electrode core, the negative electrode plate comprising a negative electrode core and a negative electrode active material layer disposed on the negative electrode core, wherein, At least one of the positive and negative electrode plates has a plurality of electrode tabs protruding outward from the region in the electrode core where no electrode active material layer is disposed. The electrode tabs have arc-shaped folds. The plurality of electrode tabs are engaged with the electrode current collector in a stacked state, and the portion of the electrode tabs that is engaged with the electrode current collector has the arc-shaped folds.

6. The battery according to any one of claims 1 to 5, wherein, The top of the arc-shaped folds is convex in the direction of the protrusion of the electrode tab.

7. The battery according to any one of claims 1 to 5, wherein, The arc-shaped folds have an asymmetrical shape relative to the width direction orthogonal to the protruding direction of the electrode tab.

8. The battery according to any one of claims 2 to 5, wherein, Multiple electrode tabs of different lengths in the protruding direction are engaged with the electrode current collector in a stacked state.

9. The battery according to claim 8, wherein, Among the plurality of electrode tabs with different lengths in the protruding direction, the lengths in the protruding direction from the root of the plurality of electrode tabs to the apex of the arc-shaped fold are approximately the same.

10. A method for manufacturing an electrode plate, wherein the method is a method for manufacturing an electrode plate having an electrode core and an electrode active material layer formed on the electrode core, wherein, have: The process of preparing an electrode precursor includes an electrode active material layer forming region on the electrode core where the electrode active material layer is formed, and an electrode core exposure region where the electrode active material layer is not formed and the electrode core is exposed. The process of processing the exposed area of ​​the electrode core to produce multiple electrode tabs protruding outward from the exposed area of ​​the electrode core; as well as The process of using rollers to form arc-shaped folds on the electrode tabs. In the process of preparing the electrode precursor, a roller press is used to form linear folds in the exposed area of ​​the electrode core.

11. A method for manufacturing a battery, the battery comprising a pair of electrode plates facing each other separated by a separator, wherein, The battery manufacturing method uses the electrode plate manufacturing method of claim 10 to manufacture at least one of the pair of electrode plates.

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