battery

Abstract

The present application provides a battery, and provides a technology for obtaining a battery with a wound electrode body at high productivity. In a preferred form of the battery disclosed herein, the maximum value of the root width of each of the plurality of positive electrode sheets (22t) is 15 mm or more, the region including the positive electrode (22) from one side of the outer surface of both ends in the stacking direction (X) of the stacked structure (28) to the 5th layer is set as the 1st outermost periphery vicinity region, the region including the positive electrode (22) from the other side of the outer surface of both ends to the 5th layer is set as the 2nd outermost periphery vicinity region, the number of positive electrode sheets (22t) in the 1st outermost periphery vicinity region is set as A and the number of layers of the positive electrode (22) is set as B, the number of positive electrode sheets (22t) in the 2nd outermost periphery vicinity region is set as C and the number of layers of the positive electrode (22) is set as D, and A / B and C / D are less than 1.

Description

Technical Field

[0001] This disclosure relates to batteries. Background Technology

[0002] For example, Patent Document 1 discloses a battery in which a positive electrode tab group is provided at one end along the longitudinal direction of a wound electrode body, and a negative electrode tab group is provided at the other end. Furthermore, it discloses a technique for connecting the aforementioned tab groups to the electrode current collector in a bent state.

[0003] Existing technical documents

[0004] Patent Document 1: International Publication No. 2021 / 060010 Summary of the Invention

[0005] However, typically, the wound electrode body described above is manufactured by winding a strip-shaped current collector and the positive and negative electrodes (hereinafter, sometimes collectively referred to as "electrodes") formed at multiple locations along the strip direction within the current collector, with a separator between them, onto a winding core and then shaping it into a flat shape. The rotational speed of the winding core during winding is constant; however, the thickness of the component increases with each turn, thus lengthening the winding time for each turn. That is, the outer periphery of the wound electrode body is wound at a relatively high speed compared to the inner periphery, and therefore the outer periphery sheet may break due to contact with the winding core, etc. Consequently, the yield of the wound electrode body may decrease, and this is not preferred.

[0006] The purpose of this disclosure is to provide a technique for obtaining batteries with wound electrodes in high productivity.

[0007] To achieve the above objectives, this disclosure provides a battery comprising: a flat wound electrode body formed by winding a first electrode and a second electrode with a separator between them; and a battery casing that houses the wound electrode body. The wound electrode body has a stacked structure in which multiple first electrodes and second electrodes are stacked together with the partition plate in between. Multiple sheets connected to the first electrode protrude from one end of the winding axis of the wound electrode body. The maximum root width of each of the multiple sheets is 15 mm or more. The region containing the first electrode up to the 5th layer from one of the outer surfaces of the two ends in the stacking direction of the stacked structure is designated as the first outermost periphery region. The region containing the first electrode up to the 5th layer from the other side of the outer surfaces of the two ends is designated as the second outermost periphery region. In the first outermost periphery region, the number of sheets is designated as A and the number of stacks of the first electrode is designated as B. In the second outermost periphery region, the number of sheets is designated as C and the number of stacks of the first electrode is designated as D. At least one of A / B and C / D is less than 1.

[0008] In this way, by removing the sheets on the outer periphery of the wound electrode body, sheet breakage during winding can be appropriately suppressed. As a result, batteries with wound electrode bodies can be obtained with high productivity.

[0009] In a preferred embodiment of the battery disclosed herein, the A / B ratio is less than 1, and the C / D ratio is less than 1. According to this structure, sheet breakage during winding can be better suppressed. Furthermore, in several embodiments, at least one of the A / B ratio and the C / D ratio is less than 3 / 5.

[0010] In a preferred embodiment of the battery disclosed herein, the average of the shortest distances from the end of one of the plurality of sheets of the wound electrode body located on one side relative to the winding center to the tip of the sheet in the protruding direction is less than the average of the shortest distances from the plurality of sheets located on the other side relative to the winding center. According to this structure, when the plurality of sheets of the wound electrode body are assembled, the tip portions of the sheets can be properly aligned, which is therefore preferred.

[0011] In one of the above configurations, A / B is less than 1. Furthermore, in several configurations, C / D is less than 1.

[0012] In a preferred embodiment of the battery disclosed herein, the width of the first electrode is 150 mm or more. If the first electrode is wide in a direction orthogonal to the strip direction, warping or other issues can easily occur during winding, thereby increasing the likelihood of breakage of the sheet surrounding the outer periphery of the electrode body. Therefore, the above-described structure is suitable for applying the technology disclosed herein.

[0013] In a preferred embodiment of the battery disclosed herein, the first electrode is a positive electrode, comprising a positive current collector and positive active material layers formed on both sides of the positive current collector, the positive current collector being made of aluminum or an aluminum alloy, and the density of the positive active material layers being 3.00 g / cm³. 3 That's all. Therefore, if the positive electrode has a high density of active material layer, warping or other issues can easily occur during winding, which in turn can easily lead to breakage of the sheet on the outer side of the wound electrode body. Therefore, the above structure is suitable as an application of the technology disclosed herein. Attached Figure Description

[0014] Figure 1 This is a schematic perspective view of a battery according to one embodiment.

[0015] Figure 2 It is along Figure 1 A schematic longitudinal section of line II-II.

[0016] Figure 3 It is along Figure 1 A schematic longitudinal section of line III-III.

[0017] Figure 4 It is along Figure 1 A schematic cross-sectional view of line IV-IV.

[0018] Figure 5 This is a schematic perspective view of the electrode assembly mounted on the sealing plate.

[0019] Figure 6 It is a perspective view schematically showing an electrode body with a positive second collector and a negative second collector installed.

[0020] Figure 7 This is a schematic diagram showing the structure of the wound electrode.

[0021] Figure 8 It is a perspective view schematically showing a sealing plate with a positive terminal, a negative terminal, a positive first collector, a negative first collector, a positive insulating component, and a negative insulating component installed.

[0022] Figure 9 It is Figure 8 A 3D view of the sealing plate turned upside down.

[0023] Figure 10 This is a schematic diagram showing the shape of a wound electrode body before winding according to one embodiment.

[0024] Figure 11This is a schematic diagram used to illustrate the shape of a wound electrode body according to one embodiment.

[0025] Figure 12A It is along Figure 11 A schematic cross-sectional view of line XII-XII.

[0026] Figure 12B It is along Figure 11 A schematic cross-sectional view of line XII-XII.

[0027] Figure 13 It pertains to the second embodiment. Figure 10 Corresponding diagram.

[0028] Figure 14 It pertains to the third embodiment. Figure 10 Corresponding diagram.

[0029] (Symbol Explanation)

[0030] 10: Battery casing; 12: Encapsulation body; 14: Sealing plate; 15: Liquid injection hole; 16: Sealing component; 17: Gas vent valve; 18, 19: Terminal insertion port; 20: Electrode assembly; 20a~20c: Electrode body; 22: Positive electrode; 24: Negative electrode; 26: Separator; 30: Positive terminal; 32: Positive external conductive component; 40: Negative terminal; 42: Negative external conductive component; 50: Positive current collector; 60: Negative current collector; 70: Positive internal insulating component; 80: Negative internal insulating component; 90: Gasket; 92: External insulating component; 100: Battery. Detailed Implementation

[0031] Hereinafter, several preferred embodiments of the technology disclosed herein will be described with reference to the accompanying drawings. Furthermore, matters other than those specifically mentioned in this specification and necessary for the implementation of this disclosure (e.g., the general structure and manufacturing process of the battery not characteristic of this disclosure) can be understood as design matters by those skilled in the art based on prior art. This disclosure can be implemented based on the content disclosed herein and common technical knowledge in the art. Additionally, the following description is not intended to limit the technology disclosed herein to the following embodiments. Furthermore, the expression "A to B" indicating a range in this specification is intended to include both A and B, and to include both A and B.

[0032] 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, including all rechargeable batteries (chemical batteries) such as lithium-ion batteries or nickel-metal hydride batteries, as well as capacitors (physical batteries) such as double-layer capacitors.

[0033] <Brief overview of battery structure>

[0034] Figure 1 It is a 3D image of battery 100. Figure 2 It is along Figure 1 A schematic longitudinal section of line II-II. Figure 3 It is along Figure 1 A schematic longitudinal section of line III-III. Figure 4 It is along Figure 1 A schematic cross-sectional view of line IV-IV. In the following description, the symbols L, R, F, Rr, U, and D in the figures represent left, right, front, back, top, and bottom, respectively, and the symbols X, Y, and Z in the figures represent the short side direction of battery 100, the long side direction orthogonal to the short side direction (also referred to as the winding axis direction), and the up-down direction, respectively. However, these directions are merely for ease of explanation and do not limit the arrangement of battery 100 in any way. Furthermore, the following description applies the technology disclosed herein to both the positive and negative electrodes, but the technology disclosed herein can be applied only to the positive electrode or only to the negative electrode.

[0035] like Figure 2 As shown, the battery 100 includes a battery casing 10 and electrode bodies (here, electrode body assembly 20). In addition to the battery casing 10 and electrode body assembly 20, the battery 100 according to this embodiment also includes a positive terminal 30, a positive external conductive component 32, a negative terminal 40, a negative external conductive component 42, an external insulating component 92, a positive current collector 50, a negative current collector 60, a positive internal insulating component 70, and a negative internal insulating component 80. Furthermore, although not shown in the figures, the battery 100 according to this embodiment also includes an electrolyte. The battery 100 here is a lithium-ion secondary battery. The internal resistance of the battery 100 can be, for example, in the range of 0.2 to 2.0 mΩ. In this embodiment, the capacity per unit volume of the battery 100 is set to 40 Ah / L or more.

[0036] 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 a metal casing with a predetermined strength. Specifically, regarding the tensile strength of the metal used in the battery casing 10, a suitable value is 50 N / mm². 2 ~200N / mm 2 Regarding the physical properties (stiffness) of the metal used in the battery casing 10, a stiffness level of 20 GPa to 100 GPa is preferred. Examples of such metal materials include aluminum, aluminum alloys, iron, and iron alloys.

[0037] Furthermore, the battery casing 10 includes a package 12, a sealing plate 14, and a gas vent valve 17. The package 12 is a flat, square container with one side forming an opening 12h. Specifically, as... Figure 1 As shown, the package 12 has a generally rectangular bottom wall 12a, a pair of opposing first side walls 12b extending upward U from the short side of the bottom wall 12a, and a pair of opposing second side walls 12c extending upward U from the long side of the bottom wall 12a. An opening 12h is formed on the upper surface of the package 12, which is surrounded by the pair of first side walls 12b and the pair of second side walls 12c. A sealing plate 14 is mounted on the package 12 to block the opening 12h of the package 12. In plan view, the sealing plate 14 is a generally rectangular plate. The sealing plate 14 is opposite the bottom wall 12a of the package 12. The battery casing 10 is formed by joining the sealing plate 14 to the periphery of the opening 12h of the package 12 (e.g., by welding). For example, the sealing plate 14 can be joined by welding such as laser welding.

[0038] like Figure 1 as well as Figure 2 As shown, a gas discharge valve 17 is formed on the sealing plate 14. The gas discharge valve 17 is configured to open and discharge gas from the battery housing 10 when the pressure inside the battery housing 10 reaches a predetermined value or higher.

[0039] In addition to the gas vent valve 17, the sealing plate 14 also includes an injection hole 15 and two terminal insertion ports 18 and 19. The injection hole 15 communicates with the internal space of the package 12 and is an opening provided during the battery 100 manufacturing process for injecting electrolyte. The injection hole 15 is sealed by a sealing member 16. A blind rivet is preferably used as the sealing member 16. This allows the sealing member 16 to be securely fixed inside the battery casing 10. Furthermore, the diameter of the injection hole 15 can be set to approximately 2 mm to 5 mm. The terminal insertion ports 18 and 19 are formed at both ends of the sealing plate 14 in the long side direction Y. The terminal insertion ports 18 and 19 penetrate the sealing plate 14 in the vertical direction Z. Figure 2 As shown, the positive terminal 30 is inserted into the terminal insertion port 18 on the left side (Y-direction). The negative terminal 40 is inserted into the terminal insertion port 19 on the right side (Y-direction). Furthermore, the diameter of the terminal insertion ports 18 and 19 can be set to approximately 10mm to 20mm.

[0040] Figure 5 This is a schematic perspective view of the electrode assembly 20 mounted on the sealing plate 14. In this embodiment, a plurality of (here, three) electrode bodies 20a, 20b, and 20c are housed inside the battery casing 10. Furthermore, the number of electrode bodies 20 housed inside a single battery casing 10 is not particularly limited; it can be one or more (multiple). Figure 2 As shown, on one side of the long side direction Y of each electrode body ( Figure 2 The positive current collector 50 is arranged on the left side, and on the other side in the long side direction Y ( Figure 2 The negative current collector 60 is arranged on the right side. Furthermore, the electrode bodies 20a, 20b, and 20c are each connected in parallel. However, the electrode bodies 20a, 20b, and 20c can also be connected in series. The electrode body assembly 20 is here held in place by an electrode body holder 29 (see reference 20a) made of resin sheet material. Figure 3 The state covered by the battery housing 10 is contained within the encapsulation 12.

[0041] Figure 6 This is a schematic three-dimensional view of the electrode body 20a. Figure 7 This is a schematic diagram showing the structure of electrode 20a. Furthermore, electrode 20a will be described in detail below as an example, but electrode 20b and 20c can also be configured with the same structure.

[0042] like Figure 7As shown, the electrode body 20a has a positive electrode 22, a negative electrode 24, and a separator 26. Here, the electrode body 20a is a wound electrode body in which a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 are stacked via two strip-shaped separators 26 and wound around a winding shaft WL. That is, the electrode body 20a has a stacked structure 28 formed by stacking multiple positive electrodes 22 and negative electrodes 24 via separators 26 (see reference). Figure 11 Regarding the thickness of the electrode body 20a (i.e., its width in the X direction), there are no particular limitations as long as the technical effects disclosed herein are achieved, and it can be set to, for example, 5mm to 40mm (preferably 10mm to 30mm). Furthermore, regarding the width in the direction orthogonal to the winding axis of the electrode body 20a, there are no particular limitations as long as the technical effects disclosed herein are achieved, and it can be set to, for example, 50mm to 120mm (preferably 70mm to 100mm).

[0043] The electrode body 20a has a flat shape. The electrode body 20a is disposed inside the package 12 with the winding axis WL approximately parallel to the long side direction Y. Specifically, as... Figure 3 As shown, the electrode body 20a has a pair of curved portions (R portions) 20r opposite to the bottom wall 12a of the package body 12 and the sealing plate 14, and a flat portion 20f connecting the pair of curved portions 20r and opposite to the second side wall 12c of the package body 12. The flat portion 20f extends along the second side wall 12c.

[0044] like Figure 7 As shown, the positive electrode 22 has a positive current collector 22c, a positive active material layer 22a and a positive protective layer 22p fastened to at least one surface of the positive current collector 22c. However, the positive protective layer 22p is not essential and can be omitted in other embodiments. The positive current collector 22c is strip-shaped. The positive current collector 22c is made of conductive metals such as aluminum, aluminum alloy, nickel, and stainless steel. Here, the positive current collector 22c is a metal foil, specifically an aluminum foil.

[0045] Here, regarding the width of the positive current collector 22c in the direction orthogonal to the strip direction ( Figure 7The thickness of the positive electrode current collector 22c is not particularly limited as long as the technical effects disclosed herein are achieved, and can be set to, for example, 100 mm or more. However, when the value of V is 150 mm or more or 200 mm or more, warping or other issues can easily occur during winding, which can easily lead to breakage of the outer periphery of the wound electrode. Therefore, this type of electrode is suitable for applying the technology disclosed herein. Regarding the thickness of the positive electrode current collector 22c, there are no particular limitations as long as the technical effects disclosed herein are achieved, and it is, for example, 5 μm or more, preferably 8 μm or more, and more preferably 10 μm or more. The upper limit of the thickness of the positive electrode current collector 22c is, for example, 30 μm or less, preferably 25 μm or less, and more preferably 20 μm or less. Furthermore, regarding the density of the positive electrode active material layer 22a, there are no particular limitations as long as the technical effects disclosed herein are achieved, and it can be set to, for example, 2.00 g / cm³. 3 Degree. Furthermore, the density mentioned above is 2.95 g / cm³. 3 Above (e.g., 2.98 g / cm³) 3 ), 3.00g / cm 3 In the above situations, warping and other issues are prone to occur during winding, which in turn can easily lead to breakage of the sheet on the outer side of the wound electrode body. Therefore, the technology disclosed herein is suitable as an application.

[0046] At one end of the positive current collector 22c along the long side direction Y ( Figure 7 At the left end, a plurality of positive electrode plates 22t are provided. Along the longitudinal direction of the strip-shaped positive electrode 22, a plurality of positive electrode plates 22t are provided at intervals (intermittently). The plurality of positive electrode plates 22t face one side of the winding shaft WL in the axial direction. Figure 7 (on the left side), protruding outwards relative to the separator 26. Furthermore, the positive electrode 22t can be positioned on the opposite side of the axial direction of the winding shaft WL (in... Figure 7 (The right side is indicated in the text) It can also be disposed on each side of the winding shaft WL along its axial direction. The positive electrode 22t is part of the positive current collector 22c and is made of metal foil (aluminum foil). However, the positive electrode 22t can also be a component different from the positive current collector 22c. In at least a portion of the positive electrode 22t, the positive active material layer 22a and the positive protective layer 22p are not formed, resulting in an area exposing the positive current collector 22c. Furthermore, in this embodiment, the positive electrode 22t is trapezoidal in shape, but it is not limited to this; the shape of the positive electrode 22t can be rectangular or various other shapes. Details regarding the plurality of positive electrode 22t will be described later.

[0047] like Figure 4 As shown, multiple positive electrode plates 22t are located at one end of the winding shaft WL in the axial direction. Figure 4The positive electrode sheets 22t are stacked at the left end to form a positive electrode assembly 23. Furthermore, each of the multiple positive electrode sheets 22t is bent so that its outer ends are aligned. This improves the containment of the battery housing 10 and allows for miniaturization of the battery 100. Figure 2 As shown, the positive electrode assembly 23 is electrically connected to the positive terminal 30 via the positive current collector 50. Specifically, the positive electrode assembly 23 and the second positive current collector 52 are connected at the connection point J (see reference). Figure 4 Furthermore, the second positive collector 52 is electrically connected to the positive terminal 30 via the first positive collector 51.

[0048] like Figure 7 As shown, the positive electrode active material layer 22a is configured in a strip shape along the longitudinal direction of the strip-shaped positive electrode current collector 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 attracting 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 also account for approximately 80% by mass or more, typically 90% by mass or more, and for example, 95% by mass or more. The positive electrode active material layer 22a can 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, materials such as polyvinylidene fluoride (PVdF) can be used.

[0049] like Figure 7 As shown, the positive electrode protective layer 22p is disposed in the long side direction Y at the boundary between the positive electrode current collector 22c and the positive electrode active material layer 22a. Here, the positive electrode protective layer 22p is disposed at one end of the winding shaft WL of the positive electrode current collector 22c in the axial direction. Figure 7 (The left end). However, the positive electrode protective layer 22p can also be provided at both ends in the axial direction. 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 solid content of the positive electrode protective layer 22p is set to 100% by mass, the inorganic filler can also occupy 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 also contain any component other than inorganic filler, such as conductive materials, binders, various additives, etc. The conductive materials and binders can also be the same as those exemplified as those that can be contained in the positive electrode active material layer 22a.

[0050] like Figure 7As shown, the negative electrode 24 has a negative electrode current collector 24c and a negative electrode active material layer 24a fastened to at least one surface of the negative electrode current collector 24c. The negative electrode current collector 24c is strip-shaped. The negative electrode current collector 24c is made of a conductive metal such as copper, copper alloy, nickel, or stainless steel. Here, the negative electrode current collector 24c is a metal foil, specifically a copper foil. Here, the width of the negative electrode current collector 24c in the direction orthogonal to the strip direction ( Figure 7 The value of W is not particularly limited as long as the technical effect disclosed herein is achieved, and can be, for example, 100 mm or more. However, when the value of W is 150 mm or more, or 200 mm or more, warping or other issues are more likely to occur during winding, which can easily lead to breakage of the sheet on the outer periphery of the wound electrode. Therefore, this is a suitable application of the technology disclosed herein.

[0051] At one end of the winding shaft WL of the negative current collector 24c in the axial direction ( Figure 7 At the right end, multiple negative electrode plates 24t are provided. Along the longitudinal direction of the strip-shaped negative electrode 24, multiple negative electrode plates 24t are provided at intervals (intermittently). Each of the multiple negative electrode plates 24t faces one side in the axial direction ( Figure 7 (on the right side), protruding outwards compared to the partition 26. However, the negative electrode 24t can be located at the other end in the axial direction ( Figure 7 The negative electrode 24t can be located at either end of the negative electrode current collector 24c, or at either end of the negative electrode 24c. The negative electrode 24t is part of the negative electrode current collector 24c and is made of metal foil (copper foil). However, the negative electrode 24t can also be a component different from the negative electrode current collector 24c. At least a portion of the negative electrode 24t does not have a negative electrode active material layer 24a formed, and an area exposing the negative electrode current collector 24c is provided. Furthermore, in this embodiment, the negative electrode 24t is trapezoidal in shape, but it is not limited to this; various shapes, such as a rectangular shape, are possible. Details regarding the dimensions of the multiple negative electrode 24ts will be described later.

[0052] like Figure 4 As shown, multiple negative electrode plates 24t are located at one end in the axial direction ( Figure 4 The negative electrode sheets 24t are stacked at the right end of the battery casing 100 to form a negative electrode assembly 25. The negative electrode assembly 25 is preferably positioned symmetrically to the positive electrode assembly 23 in the axial direction. Furthermore, each of the plurality of negative electrode sheets 24t is bent such that its outer ends are aligned. This improves the containment capacity of the battery casing 10 and allows for miniaturization of the battery 100. Figure 2 As shown, the negative electrode assembly 25 is electrically connected to the negative terminal 40 via the negative electrode current collector 60. Specifically, the negative electrode assembly 25 and the second negative electrode current collector 62 are connected at the connection point J (see reference). Figure 4Furthermore, the second negative collector 62 is electrically connected to the negative terminal 40 via the first negative collector 61.

[0053] like Figure 7 As shown, the negative electrode active material layer 24a is configured in a strip shape along the longitudinal direction of the strip-shaped negative electrode current collector 24c. The negative electrode active material layer 24a contains a negative electrode active material (e.g., carbon material such as graphite) capable of reversibly adsorbing and releasing charge carriers. When the overall solid content of the negative electrode active material layer 24a is set to 100% by mass, the negative electrode active material can also occupy 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 can also contain any components other than the negative electrode active material, such as binders, dispersants, and various additives. As a binder, rubbers such as styrene-butadiene rubber (SBR) can be used. As a dispersant, cellulose-based materials such as carboxymethyl cellulose (CMC) can be used.

[0054] Next, details will be provided regarding the plurality of positive electrode plates 22t and the plurality of negative electrode plates 24t included in the electrode body 20a according to this embodiment. Here, Figure 10 This is a schematic diagram showing the shape of the electrode body 20a according to this embodiment before winding. Figure 11 This is a schematic diagram used to illustrate the shape of the electrode body 20a according to this embodiment. Figure 12A as well as Figure 12B It is along Figure 11 A schematic cross-sectional view of line XII-XII. (See attached image.) Figure 10 as well as Figure 12A As shown, the sizes of the multiple positive electrode plates 22t and negative electrode plates 24t in the protruding direction differ from each other in the way the outer ends are aligned during bending. Furthermore, as... Figure 4 As shown, in this embodiment, multiple positive electrode plates 22t existing in the first region P and the second region Q are aggregated at a position that is unevenly distributed in the first region P.

[0055] like Figure 12A As shown, in this embodiment, the region comprising the positive electrode 22 (negative electrode 24) extending from one of the outer surfaces at both ends of the stacking direction X of the stacked structure 28 up to the 5th layer is designated as the first outermost peripheral region R, and the region comprising the positive electrode 22 (negative electrode 24) extending from the other of the outer surfaces at both ends up to the 5th layer is designated as the second outermost peripheral region S. Furthermore, as... Figure 12AAs shown, in this embodiment, the side of the electrode body 20a containing the first outermost peripheral region R relative to the winding center O is designated as the first region P, and the other side of the electrode body 20a containing the second outermost peripheral region S relative to the winding center O is designated as the second region Q. In this embodiment, a portion of the positive electrode sheet 22t (and) is removed from the first outermost peripheral region R. Figure 12A 22t 10 (equivalent) and negative electrode 24t ( Figure 12A 24t 10 In the region S near the second outermost periphery, a portion of the positive electrode 22t (and) was removed. Figure 12A 22t 10 (equivalent to '、22t9') and negative electrode 24t ... Figure 12A 24t 10 ',24t9' is equivalent). Furthermore, in Figure 12A as well as Figure 12B In the diagram, the removed positive electrode 22t and negative electrode 24t are indicated by dashed lines. By removing the plates from the outer periphery of the electrode body 20a, plate breakage during winding can be appropriately suppressed.

[0056] In addition, such as Figure 12A As shown, the positive electrode plates 22t in the first region P are designated as 22t1, 22t2, ..., 22t9, and the positive electrode plates 22t in the second region Q are designated as 22t1', 22t2', ..., 22t8'. Additionally, as... Figure 12B As shown, the shortest distance (hereinafter also referred to as "the shortest distance of the positive electrode") from one end 21a of the electrode body 20a to the top of the positive electrode 22t in the protruding direction of the positive electrode 22t1, 22t2, ..., 22t9 is set as 22h1, 22h2, ..., 22h9, respectively. The shortest distance from one end 21a of the electrode body 20a to the top of the positive electrode 22t in the protruding direction of the positive electrode 22t1', 22t2', ..., 22t8' is set as 22h1', 22h2', ..., 22h8', respectively. Similarly, the shortest distances of the negative electrode 24t are set as 24t1, 24t2, ..., 24t9 for the first region P, and 24t1', 24t2', ..., 24t8' for the second region Q (see reference). Figure 12AFurthermore, the shortest distance (hereinafter also referred to as "the shortest distance of the negative electrode") from the other end 21b of the electrode body 20a to the top of the negative electrode 24t in the protruding direction of the negative electrode 24t1, 24t2, ..., 24t9 is set to 24h1, 24h2, ..., 24h9 respectively, and the shortest distance from the other end 21b of the electrode body 20a to the top of the negative electrode 24t8' in the protruding direction of the negative electrode 24t1', 24t2', ..., 24t8' is set to 24h1', 24h2', ..., 24h8' respectively (see reference). Figure 12B ).

[0057] As described above, in this embodiment, the positive electrode 22t is removed from the region R near the first outermost periphery. 10 And 24t of negative electrode film 10 The positive electrode 22t was removed in region S near the second outermost periphery. 10 '、22t9' and negative electrode 24t 10 '、24t9'. That is, in the first outermost peripheral region R, the number of positive electrode sheets 22t (negative electrode sheets 24t) is set as A and the number of stacked positive electrode 22 (negative electrode 24) layers is set as B. In the second outermost peripheral region S, the number of positive electrode sheets 22t (negative electrode sheets 24t) is set as C and the number of stacked positive electrode 22 (negative electrode 24) layers is set as D. A / B is 4 / 5 (i.e., less than 1), and C / D is 3 / 5 (i.e., less than 1). Here, the above-mentioned number of stacked positive electrodes represents the number of layers in which positive electrode sheets are formed, which also includes layers in which positive electrode sheets are formed but without positive electrode active material layers or positive electrode protective layers (for example, refer to...). Figure 10 The concept of the first layer (in the process of manufacturing the electrode). The same applies to the number of layers in the negative electrode. Furthermore, the removal of the positive electrode sheet 22t can be performed either during the manufacturing of the positive electrode 22 or after the electrode body is formed into a flat shape. However, from the viewpoint that it is easier to manufacture the electrode body 20a, it is preferable to remove it during the manufacturing of the positive electrode 22. For example, the removal of the positive electrode sheet 22t can be carried out by laser cutting or the like. The same applies to the negative electrode sheet 24t.

[0058] Furthermore, while A / B is set to 4 / 5 and C / D to 3 / 5, this is not a limitation. A / B can also be, for example, 0. From the viewpoint of easily homogenizing potential non-uniformity in the electrode body 20a, it is preferable to set it to 1 / 5 or more, or 2 / 5 or more. Additionally, A / B can be set to 4 / 5 or less (e.g., less than 4 / 5) or 3 / 5 or less (e.g., less than 3 / 5). The same applies to C / D. Furthermore, the values ​​of A / B and C / D can be the same or different.

[0059] The maximum root width of each of the plurality of positive electrode plates 22t in the electrode body 20a (in this embodiment, the same as the maximum root width of the positive electrode plates 22t in the electrode body 20a). Figure 10 (equivalent to 22T) and the maximum root width of each of the multiple negative electrode plates 24t (in this embodiment, equivalent to 22T) Figure 10 The root width of the positive electrode sheet 22t is 15 mm or more (preferably 20 mm or more). Regarding the upper limit of the root width, there is no particular limitation as long as the technical effects disclosed herein are achieved, and it can be set to, for example, 40 mm or less. If the root width is large, breakage can be appropriately suppressed, thus appropriately preventing a decrease in the yield of the electrode body. Furthermore, when the total number of positive electrode sheets 22t included in the electrode body 20a is set to 100%, it is ideally, preferably 50% or more, 60% or more, more preferably 70% or more, 80% or more, and even more preferably 90% or more (or 100%) of the positive electrode sheets 22t have a root width of 15 mm or more. Regarding the shortest distance from the root of the positive electrode sheet 22t to the tip portion in the protruding direction, there is no particular limitation as long as the technical effects disclosed herein are achieved, and it can be set to, for example, 5 mm to 50 mm (preferably 10 mm to 30 mm). The same applies to the negative electrode sheet 24t. In addition, the thickness of the positive electrode 22t and the negative electrode 24t can be set to, for example, 5μm to 30μm.

[0060] And, as Figure 12B As shown, in this embodiment, the shortest distance between the outer end of the second region Q and the outer end of the first region P along the thickness direction X of the electrode body 20a is formed to gradually decrease. Here, it is not limited to this; the ratio of the shortest distance between adjacent positive electrode pieces 22t in the first region P and the second region Q to the shortest distance between the positive electrode pieces 22t in the second region Q and the positive electrode pieces 22t in the first region P can be set to, for example, 1.1 or more, or 1.2 or more. Furthermore, there is no particular limitation on the upper limit of the ratio of the shortest distances of the positive electrode pieces 22t, as long as the technical effects disclosed herein are achieved; it can be set to, for example, 1.4 or less, or 1.3 or less. The same applies to the negative electrode piece 24t.

[0061] Furthermore, the average of the shortest distances (22h1, 22h2, ..., 22h9) of the multiple positive electrode plates 22t existing in region 1 P is less than the average of the shortest distances (22h1', 22h2', ..., 22h8') of the multiple positive electrode plates 22t existing in region 2 Q. Also, the average of the shortest distances (24h1, 24h2, ..., 24h9) of the multiple negative electrode plates 24t existing in region 1 P is less than the average of the shortest distances (24h1', 24h2', ..., 24h8') of the multiple negative electrode plates 24t existing in region 2 Q.

[0062] Furthermore, in this embodiment, the number of positive electrode plates 22t and negative electrode plates 24t provided in the electrode body 20a is set to 17, but it is not limited to this. The number of positive electrode plates provided in the electrode body is, for example, 10 or more, and from the viewpoint of appropriately reducing the resistance of the electrode body, it can be preferably set to 15 or more, 20 or more, and more preferably 30 or more. The same applies to the number of negative electrode plates. In addition, the same applies to the second and third embodiments described later.

[0063] like Figure 7 As shown, the separator 26 is a component that insulates the positive electrode active material layer 22a of the positive electrode 22 from the negative electrode active material layer 24a of the negative electrode 24. For example, a porous sheet made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is suitable as the separator 26. The separator 26 may also have a substrate portion made of a porous sheet made of resin, and a heat resistance layer (HRL) provided on at least one surface of the substrate portion and containing an inorganic filler. For example, alumina, boehmite, aluminum hydroxide, and titanium dioxide can be used as the inorganic filler.

[0064] The electrolyte can be the same as before, without any 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 include, for example, fluorinated lithium salts such as LiPF6. The electrolyte may also be in solid form (solid electrolyte) and integrated with the electrode assembly 20.

[0065] like Figure 2 As shown, the positive terminal 30 is inserted into one end of the sealing plate 14 in the Y direction along its long side. Figure 2 The positive terminal 30 is preferably made of metal, more preferably of, for example, aluminum or an aluminum alloy. On the other hand, the negative terminal 40 is inserted into the end formed on the other side of the long side direction Y of the sealing plate 14. Figure 2The terminal insertion port 19 is located at the right end of the battery casing 10. Furthermore, the negative terminal 40 is preferably made of metal, more preferably of, for example, copper or a copper alloy. Here, these electrode terminals (positive terminal 30, negative terminal 40) protrude from the same side of the battery casing 10 (specifically, the sealing plate 14). However, the positive terminal 30 and the negative terminal 40 may also protrude from different sides of the battery casing 10. Additionally, the electrode terminals (positive terminal 30, negative terminal 40) inserted into the terminal insertion ports 18, 19 are preferably fixed to the sealing plate 14 by riveting or the like.

[0066] As mentioned above, such as Figure 2 As shown, the positive terminal 30 is connected inside the package 12 to the positive terminal 22 of each electrode body (reference) via the positive current collector 50 (positive first current collector 51, positive second current collector 52). Figure 7 Electrical connection. The positive terminal 30 is insulated from the sealing plate 14 by the positive internal insulating member 70 and the gasket 90. Furthermore, the positive internal insulating member 70 has a base portion 70a located between the first positive current collector 51 and the sealing plate 14, and a protrusion 70b protruding from the base portion 70a toward the electrode assembly 20. The positive terminal 30, exposed to the outside of the battery casing 10 through the terminal insertion port 18, is connected to the positive external conductive member 32 outside the sealing plate 14. On the other hand, as... Figure 2 As shown, the negative terminal 40 is connected to the negative terminals 24 of each electrode body (see reference) inside the package 12 via the negative current collector 60 (negative first current collector 61, negative second current collector 62). Figure 7 Electrical connection. The negative terminal 40 is insulated from the sealing plate 14 by the negative internal insulating member 80 and the gasket 90. Furthermore, similar to the positive internal insulating member 70, the negative internal insulating member 80 also has a base portion 80a located between the first negative current collector 61 and the sealing plate 14, and a protrusion 80b protruding from the base portion 80a toward the electrode assembly 20. The negative terminal 40, exposed to the outside of the battery casing 10 through the terminal insertion port 19, is connected to the negative external conductive member 42 outside the sealing plate 14. An external insulating member 92 exists between the aforementioned external conductive members (positive external conductive member 32, negative external conductive member 42) and the outer surface 14d of the sealing plate 14. The external insulating member 92 insulates the external conductive members 32 and 42 from the sealing plate 14.

[0067] Furthermore, the protrusions 70b and 80b of the aforementioned internal insulating components (positive electrode internal insulating component 70 and negative electrode internal insulating component 80) are disposed between the sealing plate 14 and the electrode assembly 20. The protrusions 70b and 80b of the internal insulating components restrict the upward movement of the electrode assembly 20, preventing contact between the sealing plate 14 and the electrode assembly 20.

[0068] <Battery Manufacturing Methods>

[0069] In the manufacturing method of battery 100, the battery casing 10 (encapsulation body 12 and sealing plate 14), electrode assembly 20 (electrode bodies 20a, 20b, 20c), electrolyte, positive terminal 30, negative terminal 40, positive electrode current collector 50 (positive electrode first current collector 51 and positive electrode second current collector 52), negative electrode current collector 60 (negative electrode first current collector 61 and negative electrode second current collector 62), positive electrode internal insulation component 70, and negative electrode internal insulation component 80, as described above, can be manufactured, for example, by a manufacturing method including a first mounting step, a second mounting step, an insertion step, and a sealing step. Furthermore, the manufacturing method disclosed herein may also include other steps at any stage.

[0070] In the first installation process, manufacturing such as Figure 8 , Figure 9 The first integrated body shown. Specifically, the positive terminal 30, the first positive current collector 51, the positive internal insulation component 70, the negative terminal 40, the first negative current collector 61, and the negative internal insulation component 80 are first installed on the sealing plate 14.

[0071] The positive terminal 30, the first positive current collector 51, and the internal positive insulation component 70 are fixed to the sealing plate 14, for example, by riveting. A gasket 90 is sandwiched between the outer surface of the sealing plate 14 and the positive terminal 30, and the internal positive insulation component 70 is sandwiched between the inner surface of the sealing plate 14 and the first positive current collector 51, thus performing the riveting process. Furthermore, the material of the gasket 90 can be the same as that of the internal positive insulation component 70. Specifically, before riveting, the positive terminal 30 is inserted sequentially from above the sealing plate 14 into the through hole of the gasket 90, the terminal insertion port 18 of the sealing plate 14, the through hole of the internal positive insulation component 70, and the through hole 51h of the first positive current collector 51, protruding below the sealing plate 14. Then, the portion protruding downwards from the sealing plate 14 relative to the positive terminal 30 is riveted by applying compressive force in the vertical direction Z. Therefore, at the top of the positive terminal 30 ( Figure 2 The lower end of the part forms a riveting part.

[0072] Through this riveting process, the gasket 90, sealing plate 14, positive electrode internal insulation component 70, and positive electrode first collector 51 are integrally fixed to the sealing plate 14, and the terminal insertion port 18 is sealed. Furthermore, the riveted portion can also be welded to the positive electrode first collector 51. This further improves conductivity reliability.

[0073] The fixing of the negative terminal 40, the first negative current collector 61, and the internal insulating member 80 can be performed in the same manner as the positive terminal side. That is, before riveting, the negative terminal 40 is inserted sequentially from above the sealing plate 14 into the through hole of the gasket, the terminal insertion port 19 of the sealing plate 14, the through hole of the internal insulating member 80, and the through hole 61h of the first negative current collector 61, protruding below the sealing plate 14. Then, the portion protruding downwards from the sealing plate 14 relative to the negative terminal 40 is riveted by applying compressive force in the vertical direction Z. Thus, at the top of the negative terminal 40 ( Figure 2 The lower end of the part forms a riveting part.

[0074] Next, the positive electrode external conductive component 32 and the negative electrode external conductive component 42 are installed on the outer surface of the sealing plate 14, separated by the external insulating component 92. Furthermore, the material of the external insulating component 92 can be the same as that of the positive electrode internal insulating component 70. Additionally, the timing of installing the positive electrode external conductive component 32 and the negative electrode external conductive component 42 can be after the insertion process (e.g., after sealing the injection hole 15).

[0075] In the second assembly step, the first integrated assembly manufactured in the first assembly step is used to manufacture, for example... Figure 5 The second integrated assembly shown. That is, the electrode body assembly 20 is manufactured integrally with the sealing plate 14. Furthermore, a positive electrode 22 having multiple positive electrode plates 22t as described above, a negative electrode 24 having multiple negative electrode plates 24t as described above, and a separator can also be prepared, and the electrode body 20a can be manufactured according to a conventionally known method for manufacturing wound electrode bodies. And, as... Figure 6 As shown, three electrode bodies 20a, each equipped with a positive electrode second current collector 52 and a negative electrode second current collector 62, are prepared and arranged as electrode bodies 20a, 20b, and 20c in the short-side direction X. Alternatively, electrode bodies 20a, 20b, and 20c can be arranged in parallel such that the positive electrode second current collector 52 is positioned on one side in the long-side direction Y. Figure 5 (on the left side), and the negative electrode second collector 62 is positioned on the other side in the long side direction Y. Figure 5 (Right side).

[0076] Next, in such Figure 4With the multiple positive electrode sheets 22t bent as shown, the first positive electrode current collector 51 fixed to the sealing plate 14 and the second positive electrode current collector 52 of the electrode bodies 20a, 20b, and 20c are respectively joined. Similarly, with the multiple negative electrode sheets 24t bent, the first negative electrode current collector 61 fixed to the sealing plate 14 and the second negative electrode current collector 62 of the electrode bodies 20a, 20b, and 20c are respectively joined. Joining methods include, for example, ultrasonic welding, resistance welding, and laser welding. In particular, welding performed by irradiation with high-energy rays such as lasers is preferred. Through this welding process, joint portions are formed in the recesses of the second positive electrode current collector 52 and the second negative electrode current collector 62, respectively.

[0077] In the insertion process, the second integrated assembly manufactured in the second mounting process is housed within the internal space of the package 12. 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 within the electrode holder 29. Then, the electrode assembly 20, covered by the electrode holder 29, is inserted into the package 12. If the electrode assembly 20 is heavy, approximately 1 kg or more, for example, 1.5 kg or more, or even 2 to 3 kg, the long sidewall 12b of the package 12 can be configured to intersect the direction of gravity (making the package 12 transverse), and the electrode assembly 20 can be inserted into the package 12.

[0078] In the sealing process, the sealing plate 14 is joined to the edge of the opening 12h of the package 12 to seal the opening 12h. The sealing process can be performed simultaneously with or after the insertion process. In the sealing process, it is preferable to weld the package 12 and the sealing plate 14 together. The welding of the package 12 and the sealing plate 14 can be performed by, for example, laser welding. Afterward, electrolyte is injected through the injection hole 15, and the injection hole 15 is blocked by the sealing member 16, thereby sealing the battery 100. As described above, the battery 100 can be manufactured.

[0079] The battery 100 can be used for various applications, including those where it may be subjected to external forces such as vibration and impact during use, such as as a power source (drive power source) for motors mounted on moving bodies (typically passenger cars, trucks, etc.). The type of vehicle is not particularly limited; examples include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), and battery electric vehicles (BEVs). The battery 100 can also be used as a battery pack formed by arranging multiple batteries 100 in a predetermined arrangement direction and applying a load to the arrangement direction using a constraint mechanism.

[0080] The above description illustrates several embodiments of this disclosure, but these embodiments are merely examples. This disclosure can be implemented in various other ways. It can be implemented based on the content disclosed in this specification and common technical knowledge in the art. The technology described in the claims includes 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, any technical feature not described as essential can be appropriately removed.

[0081] For example, in the above embodiments, the shortest distances of the multiple positive electrode plates (multiple negative electrode plates) are different, but this is not a limitation. The techniques disclosed herein can also be applied to cases where, for example, the shortest distances of the multiple positive electrode plates (multiple negative electrode plates) are set to be approximately the same.

[0082] For example Figure 13 It pertains to the second embodiment. Figure 10 Corresponding diagram. (See image below) Figure 13 As shown, in the second embodiment, the positive electrode 22t is removed from the region R near the first outermost periphery. 10 And 24t of negative electrode film 10 In the above situation, A / B becomes 9 / 10 = 0.9.

[0083] For example Figure 14 It pertains to the third embodiment. Figure 10 Corresponding diagram. (See image below) Figure 14 As shown, in the third embodiment, the positive electrode 22t is removed from the region S near the second outermost periphery. 10 'and 24t of negative electrode film' 10 In the above case, the C / D ratio becomes 9 / 10 = 0.9.

[0084] That is, as in the second and third embodiments described above, it is also possible to configure it so that at least one of A / B and C / D is less than 1.

Claims

1. A battery comprising: A flat, wound electrode body formed by winding the first and second electrodes together with a partition between them; and The battery casing houses the wound electrode body, wherein... The wound electrode body has a stacked structure consisting of multiple layers of the first electrode and the second electrode stacked with the partition plate in between. Multiple plates connected to the first electrode protrude from one end in the winding axis direction of the wound electrode body, and these multiple plates are part of the current collector of the first electrode. Each of the plurality of pieces has a root width of 15mm or more. The region comprising the first electrode extending from one of the outer surfaces at both ends of the stacked structure up to the fifth layer is designated as the first outermost periphery region, and the region comprising the first electrode extending from the other of the outer surfaces at both ends up to the fifth layer is designated as the second outermost periphery region. When the number of sheets is set to A and the number of layers of the first electrode is set to B in the region near the first outermost periphery, and the number of sheets is set to C and the number of layers of the first electrode is set to D in the region near the second outermost periphery, At least one of A / B and C / D is less than 1.

2. The battery according to claim 1, wherein, The ratio of A to B is less than 1, and the ratio of C to D is less than 1.

3. The battery according to claim 1 or 2, wherein, At least one of A / B and C / D is less than 3 / 5.

4. The battery according to claim 1 or 2, wherein, The average of the shortest distances from the end of the one side to the top of the protruding part of the plurality of pieces of the wound electrode relative to the winding center is less than the average of the shortest distances from the other side of the plurality of pieces relative to the winding center.

5. The battery according to claim 1, wherein, The A / B ratio is less than 1.

6. The battery according to claim 1, wherein, The C / D ratio is less than 1.

7. The battery according to claim 1 or 2, wherein, The width of the first electrode is 150 mm or more.

8. The battery according to claim 1 or 2, wherein, The first electrode is the positive electrode. The positive electrode includes a positive current collector and positive active material layers formed on both sides of the positive current collector. The positive current collector is made of aluminum or an aluminum alloy. The density of the positive electrode active material layer is 3.00 g / cm³. 3 above.

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