Battery

Abstract

The invention relates to a battery. The battery is provided with an electrode body having a positive electrode tab at one end in a first direction and a negative electrode tab at the other end in the first direction, and a plurality of winding fixing bands respectively adhered to the end in the longitudinal direction of a belt-shaped separator and positioned at the end of the outer surface of the electrode body, each of the plurality of winding fixing tapes has a rectangular shape having a long side and a short side, the plurality of winding fixing tapes are adhered to the outer surface of the electrode body at intervals in the first direction with the long sides of the rectangular shape facing in the first direction, the interval between the plurality of adjacent winding fixing tapes is 105 mm or less, the electrode body has a flat portion, and in the state of the electrode body, the winding fixing tapes are adhered to the outer surface of the electrode body at intervals in the first direction. A size of each of the plurality of wound fixing tapes in a direction orthogonal to the first direction is smaller than a size of the flat portion in the direction orthogonal to the first direction, and in the first direction, each of the plurality of wound fixing tapes is separated from an end portion of the electrode body in the first direction in an outer surface of the electrode body.

Description

[0001] This application is a divisional application of the invention patent application entitled "Battery", filed on November 5, 2021, with application number 202111303739.6. Technical Field

[0002] This invention relates to batteries. Background Technology

[0003] Conventionally, the following type of battery is known: a battery comprising a wound electrode body, wherein a strip-shaped positive electrode having a positive electrode active material layer on a positive electrode current collector and a strip-shaped negative electrode having a negative electrode active material layer on a negative electrode current collector are stacked in a strip-shaped separator and wound around a winding shaft to form the aforementioned wound electrode body (WO2015 / 146076, Japanese Patent Application Publication No. 2012-69290).

[0004] For example, WO2015 / 146076 discloses the following lithium-ion secondary battery: In order to prevent the winding of the wound electrode body from loosening, a winding fixing tape is attached to the winding end and fixed to the wound electrode body itself. Summary of the Invention

[0005] In high-capacity batteries used in applications such as automotive, the size of the wound electrode body increases. If the size of the wound electrode body increases, the winding retaining strip used to prevent slack winding also becomes longer. If the winding retaining strip is longer, it is prone to twisting when pulled out and wrinkling when attached to the wound electrode body. If wrinkles form in the winding retaining strip, steps are formed on the wound electrode body, resulting in localized increases in thickness. Consequently, during battery manufacturing or use, when pressure is applied to the wound electrode body, the wrinkled areas are forcefully pressed. As a result, unevenness may occur during the charge-discharge reaction, potentially leading to the precipitation of metallic lithium (dendrites).

[0006] The present invention was made in view of the above circumstances, and its object is to provide a battery that is less prone to wrinkling when wound and that suppresses uneven charging and discharging reactions.

[0007] According to the present invention, a battery is provided, comprising: an outer casing having a bottom wall and an opening facing the bottom wall; a sealing plate sealing the opening of the outer casing; and one or more wound electrode bodies, wherein a strip-shaped positive electrode having a positive active material layer and a strip-shaped negative electrode having a negative active material layer are stacked with a strip-shaped separator as a separation, and wound around a winding axis to form the one or more wound electrode bodies. The wound electrode bodies are housed in the outer casing such that the winding axis is along the bottom wall of the outer casing. In the winding axis direction of the wound electrode bodies, the length of the positive active material layer is 15 cm or more. On the outer surface of the wound electrode bodies, a plurality of winding fixing tapes are attached at intervals along the winding axis direction.

[0008] In the aforementioned battery, multiple winding fixing tapes are spaced apart and attached to the outer surface of the wound electrode body. Therefore, even when the length of the wound electrode body along its winding axis is relatively long (specifically, the length of the positive electrode active material layer is 15 cm or more), wrinkles on the winding fixing tape are relatively suppressed compared to attaching a single linear winding fixing tape. As a result, uneven reaction is less likely to occur during charging and discharging, thereby suppressing dendrite formation.

[0009] In a preferred embodiment of the battery disclosed herein, multiple wound electrode bodies are used. When multiple wound electrode bodies are used, the effect of wrinkles becomes particularly significant. Therefore, the technique disclosed herein is especially effective.

[0010] In a preferred embodiment of the battery disclosed herein, it comprises: a positive electrode tab assembly including a plurality of positive electrode tabs protruding from one end of the wound electrode body in the winding axis direction and electrically connected to the positive electrode; and a negative electrode tab assembly protruding from the other end of the wound electrode body in the winding axis direction and electrically connected to the negative electrode. In such a structure, the length of the wound electrode body in the winding axis direction becomes longer, making it prone to wrinkling in the winding fixing tape. Therefore, the technique disclosed herein is particularly effective.

[0011] In a preferred embodiment of the battery disclosed herein, the positive electrode tab group and the negative electrode tab group are eccentrically arranged toward the sealing plate in a direction perpendicular to the sealing plate. This structure shortens the conduction path up to the terminals.

[0012] In a preferred embodiment of the battery disclosed herein, a plurality of the aforementioned winding fixing strips are arranged on a straight line connecting the aforementioned positive electrode tab group and the aforementioned negative electrode tab group.

[0013] In a preferred embodiment of the battery disclosed herein, in the winding axis direction, when the length of the positive electrode active material layer is set to 100%, the ratio of the total length of the plurality of winding fixing strips is 20% or more and 70% or less. With such a structure, uneven reaction during charging and discharging, dendrite formation, etc., can be prevented or suppressed to a high degree.

[0014] In a preferred embodiment of the battery disclosed herein, the spacing between adjacent plurality of the aforementioned winding fixing strips is 30 mm or more and 105 mm or less. This structure prevents or effectively suppresses uneven reactions during charging and discharging, dendrite formation, and the like.

[0015] According to the present invention, a battery is provided, wherein the battery comprises: an electrode body, the electrode body being formed by stacking a positive electrode having a positive electrode active material layer and a negative electrode having a negative electrode active material layer separated by a strip-shaped separator; and a plurality of winding and fixing tapes, the plurality of winding and fixing tapes being adhered to the separator wound around the outermost periphery of the electrode body, the electrode body having a positive electrode tab disposed on the positive electrode at one end in a first direction, the positive electrode tab being bent and connected to a positive electrode current collector, the electrode body having a negative electrode tab disposed on the negative electrode at the other end in the first direction, the negative electrode tab being bent and connected to a negative electrode current collector, wherein in the first direction, the length of the positive electrode active material layer is 15 cm or more, and the plurality of winding and fixing tapes are respectively adhered to the strip-shaped separator. The diaphragm is located at the end of its long side and at the end of the outer surface of the electrode body. A plurality of winding and fixing tapes are rectangles having long and short sides. These tapes are spaced apart along the first direction with the long side of the rectangle facing the first direction. Adjacent winding and fixing tapes are spaced 105 mm or less apart. The electrode body has a flat portion. In the state of the electrode body, the dimension of each of the winding and fixing tapes in the direction orthogonal to the first direction is smaller than the dimension of the flat portion in the direction orthogonal to the first direction. Furthermore, in the first direction, the plurality of winding and fixing tapes are all located away from the end of the electrode body in the first direction on the outer surface of the electrode body. Attached Figure Description

[0016] Figure 1 This is a perspective view schematically illustrating one embodiment of a battery.

[0017] Figure 2 It is along Figure 1 A schematic longitudinal section view of line II-II.

[0018] Figure 3 It is along Figure 1 A schematic longitudinal section view of line III-III.

[0019] Figure 4 It is along Figure 1 A schematic cross-sectional view of line IV-IV.

[0020] Figure 5 It is a schematic three-dimensional view of the electrode assembly installed on the sealing plate.

[0021] Figure 6 It is a schematic three-dimensional view of an electrode body with a positive second collector and a negative second collector installed.

[0022] Figure 7 This is a schematic diagram showing the structure of the wound electrode.

[0023] Figure 8 It is a schematic representation Figure 3 A partially enlarged cross-sectional view of the upper end of the wound electrode body.

[0024] Figure 9A It is a schematic representation Figure 7 A side view of the wound electrode body.

[0025] Figure 9B It is a schematic representation Figure 7 Front view of the wound electrode body.

[0026] Figure 10 It is a schematic representation Figure 2 A magnified cross-sectional view of the vicinity of the positive end.

[0027] Figure 11 It is a schematic perspective view of a sealing plate with a positive terminal, a negative terminal, a first positive current collector, a first negative current collector, a positive insulating component, and a negative insulating component installed.

[0028] Figure 12 It is Figure 11 A 3D view of the sealing plate turned upside down.

[0029] Figure 13 This is a schematic cross-sectional view illustrating the battery insertion process according to one embodiment.

[0030] Figure 14A This schematically represents the first wound electrode body of a modified battery. Figure 9B Corresponding diagram.

[0031] Figure 14B This schematically represents the second wound electrode of a modified battery. Figure 9B Corresponding diagram.

[0032] Explanation of reference numerals in the attached figures

[0033] 12 outer body

[0034] 14 Sealing Board

[0035] 20 electrode assembly

[0036] 20a, 20b, 20c wound electrode bodies

[0037] 20f flat section

[0038] 20r bending section

[0039] 23 Positive electrode tabs

[0040] 25 negative electrode ear group

[0041] 28-wound fixing tape

[0042] 100 batteries Detailed Implementation

[0043] Hereinafter, with reference to the accompanying drawings, several preferred embodiments of the technology disclosed herein will be described. It should be noted that matters other than those specifically mentioned in this specification and matters necessary for the implementation of the invention (e.g., the general structure and manufacturing process of a battery not characterized by the present invention) can be understood 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~B" indicating a range in this specification includes the meaning of A or more and B or less, and includes the meanings of "preferably greater than A" and "preferably less than B".

[0044] It should be noted that in this manual, "battery" refers to all energy storage devices capable of extracting electrical energy, encompassing both primary and secondary batteries. Furthermore, in this manual, "secondary battery" refers to all energy storage devices capable of repeated charging and discharging, including lithium-ion secondary batteries, nickel-metal hydride batteries, and other so-called storage batteries (chemical batteries), as well as capacitors such as double-layer capacitors (physical batteries).

[0045] <Battery 100>

[0046] 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. It should be noted that 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 represent the direction of the short side of battery 100, the direction of the long side orthogonal to the short side, and the up-down direction, respectively. However, these directions are merely for ease of explanation and do not limit the arrangement of battery 100.

[0047] like Figure 2 As shown, the battery 100 includes a battery casing 10, an electrode assembly 20, a positive terminal 30, a negative terminal 40, a positive current collector 50, a negative current collector 60, a positive electrode insulating component 70, and a negative electrode insulating component 80. Details will be described later. The electrode assembly 20 includes wound electrode bodies 20a, 20b, and 20c (see reference). Figure 3 Although the illustration is omitted, the battery 100 here also includes an electrolyte. The battery 100 here is a lithium-ion secondary battery. The battery 100 is characterized by having wound electrode bodies 20a, 20b, and 20c; otherwise, its structure may be the same as conventional batteries.

[0048] 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 and is not particularly limited. 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 having an opening 12h; and a sealing plate (cover) 14 that blocks the opening 12h.

[0049] like Figure 1 As shown, the outer casing 12 includes: a bottom wall 12a, a pair of long sidewalls 12b extending from the bottom wall 12a and facing each other, and a pair of short sidewalls 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 sidewalls 12c is smaller than the area of ​​the long sidewalls 12b. A 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 when viewed from above. 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).

[0050] like Figure 2As shown, the sealing plate 14 is provided with an injection hole 15, a gas discharge 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 the sealing member 16. The gas discharge valve 17 is configured to break when the pressure inside the battery casing 10 reaches a specified 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 the negative terminal 40, which are installed before the sealing plate 14 (before riveting), to be inserted.

[0051] The positive terminal 30 and the negative terminal 40 are respectively fixed to the sealing plate 14. The positive terminal 30 is positioned on one side of the long side Y of the sealing plate 14. Figure 1 , Figure 2 (On the left side). The negative terminal 40 is positioned on the other side of the long side 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. Here, the positive terminal 30 and the negative terminal 40 are riveted to the periphery of the terminal lead-out holes 18 and 19 surrounding the sealing plate 14 by riveting. At the ends of the positive terminal 30 and the negative terminal 40 on the outer casing 12 side ( Figure 2 The lower end of the component has riveting portions 30c and 40c.

[0052] 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 terminal 22 of the electrode assembly 20 (see reference). Figure 7 Electrical connection. The negative terminal 40 is connected inside the outer casing 12 via the negative current collector 60 to the negative terminal 24 of the electrode assembly 20 (see reference). Figure 7 Electrical connection. The positive terminal 30 is insulated from the sealing plate 14 through the positive insulating component 70 and the washer 90. The negative terminal 40 is insulated from the sealing plate 14 through the negative insulating component 80 and the washer 90.

[0053] The positive terminal 30 is preferably made of metal, more preferably of, for example, aluminum or an aluminum alloy. 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 constructed by joining and integrating two conductive components. For example, the portion connected to the negative current collector 60 may be made of copper or a copper alloy, while the portion exposed on the outer surface of the sealing plate 14 may be made of aluminum or an aluminum alloy.

[0054] like Figure 1 As shown, plate-shaped positive electrode external conductive component 32 and negative electrode external conductive component 42 are mounted on the outer surface of the sealing plate 14. The positive electrode external conductive component 32 is electrically connected to the positive terminal 30. The negative electrode external conductive component 42 is electrically connected to the negative terminal 40. The positive electrode external conductive component 32 and negative electrode external conductive component 42 are components that provide a busbar when multiple batteries 100 are electrically connected to each other. The positive electrode external conductive component 32 and negative electrode external conductive component 42 are preferably made of metal, more preferably of, for example, aluminum or an aluminum alloy. The positive electrode external conductive component 32 and negative electrode external conductive component 42 are insulated from the sealing plate 14 by an external insulating component 92. However, the positive electrode external conductive component 32 and negative electrode external conductive component 42 are not essential and may be omitted in other embodiments.

[0055] 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 the outer casing 12 is not particularly limited; it can be two or more, or it can be one. The electrode assembly 20 is held in place by an electrode holder 29 made of resin sheet (see reference). Figure 3 The state configuration covered is located inside the outer casing 12.

[0056] Figure 6 This is a schematic perspective view 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 adopt the same structure. The wound electrode body 20a is arranged inside the outer casing 12 with its winding axis WL approximately parallel to the long side direction Y. The wound electrode body 20a is arranged inside the outer casing 12 along the bottom wall 12a and the sealing plate 14 with its winding axis WL. The wound electrode body 20a is arranged inside the outer casing 12 with its winding axis WL orthogonal to the short sidewall 12c. The end face of the wound electrode body 20a orthogonal to the winding axis WL (in other words, the laminated surface where the positive electrode 22 and the negative electrode 24 are stacked) faces the short sidewall 12c. The long side direction Y is an example of the winding axis direction.

[0057] like Figure 3As shown, the wound electrode body 20a has: a pair of curved portions (R portions) 20r facing the bottom wall 12a and the sealing plate 14 of the outer body 12; and a flat portion 20f connecting the pair of curved portions 20r and facing the long side wall 12b of the outer body 12. One side ( Figure 3 The curved portion 20r (on the upper side) is indirectly facing the sealing plate 14, separated by the positive electrode first current collector 51, the negative electrode first current collector 61, the positive electrode insulating member 70, and the negative electrode insulating member 80, which will be described later. The other side ( Figure 3 The curved portion 20r (on the lower side) is indirectly facing the bottom wall 12a via the electrode holder 29.

[0058] Figure 7 This is a schematic diagram showing the structure of the wound electrode body 20a. The wound electrode body 20a has a positive electrode 22, a negative electrode 24, and a separator 26. Here, the wound electrode body 20a is configured such that the strip-shaped positive electrode 22 and the strip-shaped negative electrode 24 are stacked with the strip-shaped separator 26 in between, and are wound around a winding shaft WL. The wound electrode body 20a has a flat shape. Such a flat shape is particularly preferred for the wound electrode body 20a. Figure 8 It is a partially enlarged cross-sectional view schematically showing the upper end of the wound electrode body 20a. Figure 8 This represents the cross-section of the wound electrode body 20a in a direction orthogonal to the winding axis WL. It should be noted that... Figure 8 The diagrams of the positive electrode tab group 23 and the negative electrode tab group 25, which will be described later, are omitted. Figure 9A This is a schematic side view of the wound electrode body 20a. Figure 9A This refers to the side (end face) of the wound electrode body 20a in a direction orthogonal to the winding axis WL. Figure 9B This is a schematic front view of the wound electrode body 20a. Figure 9B This refers to the side surface of the wound electrode body 20a along the direction of the winding axis WL.

[0059] like Figure 7 As shown, the positive electrode 22 has: a positive current collector 22c; and a positive active material layer 22a and a positive protective layer 22p fixed on 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. The positive current collector 22c is a metal foil, specifically an aluminum foil.

[0060] At one end of the long side Y of the positive current collector 22c ( Figure 7 Multiple positive electrode tabs 22t are provided at the left end. These multiple positive electrode tabs 22t face the side along the long side Y ( Figure 7The positive electrode tabs 22t protrude from the left side of the diaphragm 26. Multiple positive electrode tabs 22t protrude in the long side direction Y relative to the diaphragm 26. These multiple positive electrode tabs 22t are spaced apart (intermittently) along the length of the positive electrode 22. The positive electrode tabs 22t are part of the positive current collector 22c and are made of metal foil (aluminum foil). The positive electrode tabs 22t are the portion of the positive current collector 22c where the positive active material layer 22a and the positive protective layer 22p are not formed (exposed current collector portion). However, the positive electrode tabs 22t can also be a different component from the positive current collector 22c. Additionally, the positive electrode tabs 22t can be located at the other end in the long side direction Y. Figure 7 (The right end), or can be set at both ends of the long side Y direction respectively.

[0061] like Figure 4 As shown, multiple positive electrode tabs 22t are located at one end of the long side Y ( Figure 4 The positive electrode tabs 22t are stacked at their left ends to form a positive electrode tab assembly 23. The positive electrode tabs 22t are bent so that their outer ends are aligned. The positive electrode tab assembly 23 is electrically connected to the positive terminal 30 via a positive current collector 50. Preferably, the 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. The dimensions of the positive electrode tabs 22t (length in the long side direction Y and width orthogonal to the long side direction Y) are described in reference [reference needed]. Figure 7 Consider the state of connection with the positive current collector 50, and adjust it appropriately according to its formation position, etc.

[0062] like Figure 9A As shown, the positive electrode tab assembly 23 is eccentrically positioned towards the sealing plate 14 in the vertical direction Z (the direction perpendicular to the sealing plate 14). The positive electrode tab assembly 23 is positioned near the sealing plate 14 relative to the bottom wall 12a of the outer casing 12. Multiple positive electrode tabs 22t are arranged such that their outer ends are aligned when bent, resulting in different dimensions. In the short-side direction X, located at one end ( Figure 9A The width Wre of the positive electrode tab 22t at the left end is located at the other end ( Figure 9A The width Wf of the positive electrode tab 22t at the right end. In the positive electrode tab group 23, the height and width of the positive electrode tab 22t are measured from one side in the short side direction X. Figure 9A (left side) facing the other side ( Figure 9A The size of multiple positive electrode tabs 22t is adjusted by gradually increasing the size on the right side.

[0063] like Figure 7As shown, the positive electrode active material layer 22a is arranged in a strip shape along the length 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 adsorbing 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 occupy about 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, various additives, etc. As a conductive material, carbon materials such as acetylene black (AB) can be used. As a binder, polyvinylidene fluoride (PVdF) can be used. In high-capacity batteries used in vehicles, etc., the length L1 of the positive electrode active material layer 22a in the long side direction Y can be about 15 cm or more, for example, 20 cm or more, and further 25 cm or more.

[0064] like Figure 7 As shown, the positive electrode protective layer 22p is disposed at the boundary between the positive electrode current collector 22c and the positive electrode active material layer 22a in the long side direction Y. Here, the positive electrode protective layer 22p is disposed at one end of the positive electrode current collector 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 occupy about 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 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.

[0065] like Figure 7 As shown, the negative electrode 24 has a negative electrode current collector 24c and a negative electrode active material layer 24a fixed on 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 conductive metals such as copper, copper alloy, nickel, and stainless steel. The negative electrode current collector 24c is a metal foil, specifically a copper foil.

[0066] At one end of the long side Y of the negative current collector 24c ( Figure 7 Multiple negative electrode tabs 24t are provided at the right end. These multiple negative electrode tabs 24t face the side along the long side Y ( Figure 7The right side of the diaphragm 24 protrudes. Multiple negative electrode tabs 24t protrude in the long side direction Y relative to the diaphragm 26. The multiple negative electrode tabs 24t are spaced apart (intermittently) along the length of the negative electrode 24. The negative electrode tabs 24t are part of the negative electrode current collector 24c and are made of metal foil (copper foil). Here, the negative electrode tabs 24t are the portion of the negative electrode current collector 24c where the negative electrode active material layer 24a is not formed (exposed current collector portion). However, the negative electrode tabs 24t can also be a different component from the negative electrode current collector 24c. Additionally, the negative electrode tabs 24t can be provided at the other end in the long side direction Y ( Figure 7 (The left end), or can be set at both ends of the long side Y direction respectively.

[0067] like Figure 4 As shown, multiple negative electrode tabs 24t are located at one end in the long side direction Y ( Figure 6 The negative electrode tabs 24t are stacked at their right ends 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. Multiple negative electrode tabs 24t are bent so that their outer ends are aligned. 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. The dimensions of the multiple negative electrode tabs 24t (length in the long side direction Y and width orthogonal to the long side direction Y) are as follows: Figure 7 Consider the state of connection with the negative electrode current collector 60, and adjust it appropriately according to its formation position, etc.

[0068] The negative electrode tab assembly 25 is positioned in the same vertical direction Z as the positive electrode tab assembly 23. Although not shown in the figure, the negative electrode tab assembly 25, like the positive electrode tab assembly 23, is eccentrically positioned towards the sealing plate 14 in the vertical direction Z. The multiple negative electrode tabs 24t are arranged such that their outer ends are aligned when bent, resulting in different dimensions. In the negative electrode tab assembly 25, similar to the positive electrode tab assembly 23, the dimensions of the multiple negative electrode tabs 24t are adjusted such that their height and width gradually increase from one side in the short side direction X towards the other.

[0069] like Figure 7As shown, the negative electrode active material layer 24a is arranged in a strip shape along the length 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 materials such as graphite) capable of reversibly adsorbing 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 occupy about 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, various additives, etc. As a binder, rubbers such as styrene-butadiene rubber (SBR) can be used. As a dispersant, celluloses such as carboxymethyl cellulose (CMC) can be used. In the long side direction Y, the length L2 of the negative electrode active material layer 24a is longer than the length L1 of the positive electrode active material layer 22a.

[0070] 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. 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 separator substrate portion made of a porous sheet of resin and a heat resistance layer (HRL) formed on at least one surface of the separator substrate portion. The heat resistance layer is a layer containing inorganic fillers. For example, alumina, boehmite, aluminum hydroxide, titanium dioxide, etc., can be used as inorganic fillers. In the long side direction Y, the length L3 of the separator 26 is longer than the length L2 of the negative electrode active material layer 24a.

[0071] like Figure 8 As shown, the winding terminal 22e of the positive electrode 22 is positioned closer to the inner circumference of the winding than the winding terminal 24e of the negative electrode 24. The winding terminal 22e of the positive electrode 22 is located here in the curved portion 20r facing the sealing plate 14. The winding terminal 22e of the positive electrode 22 is positioned closer to the inner circumference of the winding than the straight line Lp perpendicular to the winding axis WL of the winding electrode body 20a and the bottom wall 12a. Figure 8 In this process, the length La from the winding terminal 22e of the positive electrode 22 to the straight line Lp is preferably 0.1 mm to 20 mm, more preferably 0.1 mm to 9 mm, and even more preferably 3 mm to 7 mm. The length La can also be 5 mm or more.

[0072] The winding terminal 24e of the negative electrode 24 is positioned closer to the outer periphery of the winding than the winding terminal 22e of the positive electrode 22. The winding terminal 24e of the negative electrode 24 is located here at the bend 20r facing the sealing plate 14. The winding terminal 24e of the negative electrode 24 is positioned closer to the outer periphery of the winding than the straight line Lp (in other words, beyond the straight line Lp). Figure 8 In the process, the length Lb from the straight line Lp to the winding terminal 24e of the negative electrode 24 is preferably 0.1 mm to 20 mm, more preferably 0.1 mm to 9 mm, and even more preferably 3 mm to 7 mm. The length Lb can also be 4 mm or more. In the bend 20r, the outermost portion 24o of the negative electrode 24 faces the inner portion 24i of the negative electrode 24, separated by the diaphragm 26.

[0073] The winding end 26e of the diaphragm 26 is positioned closer to the outer periphery of the winding than the winding end 22e of the positive electrode 22 and the winding end 24e of the negative electrode 24. The winding end 26e of the diaphragm 26 is located here on the flat portion 20f of the winding electrode body 20a. If the winding end 26e is located on the flat portion 20f, the thickness of the multiple winding electrode bodies 20a, 20b, and 20c can be effectively suppressed. Figure 8 The length of the shorter side in the X direction will cause a deviation. Figure 8 In this process, the length Lc from the winding terminal 24e of the negative electrode 24 to the winding terminal 26e of the separator 26 can be longer than the total length (La+Lb) of the lengths La and Lb. The length Lc is preferably 20 to 100 mm, more preferably 30 to 80 mm or more, and even more preferably 40 to 60 mm.

[0074] Multiple winding fixing tapes 28 are attached to the winding end 26e of the diaphragm 26 (see reference). Figure 9B Multiple winding fixing tapes 28 are attached to the outer surface of the wound electrode body 20a. The multiple winding fixing tapes 28 are attached in a manner that spans between one diaphragm 26 and another diaphragm 26. Figure 8 In this process, the length Ld from the winding terminal 24e of the negative electrode to the winding fixing tape 28 is preferably 20~70mm, more preferably 25~45mm. For example... Figure 9A As shown, in the short side direction X, multiple winding fixing strips 28 are located on the side closer to the narrow positive electrode tab 22t (wider than the wider positive electrode tab 22t) than the wider positive electrode tab 22t (wider than the wider one). This better prevents the winding of the electrode body 20a from loosening.

[0075] like Figure 8 as well as Figure 9B As shown, multiple winding fixing tapes 28 are arranged on the flat portion 20f in such a way that they do not cover the curved portion 20r. Therefore, compared to the case where the winding terminal 26e is arranged on the curved portion 20r, the thickness of the winding electrode body 20a can be suppressed. Figure 8 as well as Figure 9B(Length of the short side in the X direction). In addition, it can suppress the thickening of the boundary between the flat portion 20f and the curved portion 20r. Furthermore, it can suppress the thickness deviation of the multiple wound electrode bodies 20a, 20b, and 20c, and enable the multiple wound electrode bodies 20a, 20b, and 20c to charge and discharge in a balanced and good manner.

[0076] like Figure 9B As shown, multiple winding fixing tapes 28 are linearly attached along the long side direction Y, spaced at predetermined intervals D1 and D2 along the winding axis WL of the winding electrode body 20a. In the long side direction Y, the multiple winding fixing tapes 28 are arranged between the positive electrode tab group 23 and the negative electrode tab group 25. The multiple winding fixing tapes 28 are arranged on the straight line connecting the positive electrode tab group 23 and the negative electrode tab group 25. The multiple winding fixing tapes 28 are positioned closer to the center than the positive electrode tab group 23 and the negative electrode tab group 25. Here, the multiple winding fixing tapes 28 are each arranged within the length L1 of the positive electrode active material layer 22a.

[0077] By attaching multiple winding fixing strips 28 spaced apart at intervals D1 and D2 along the long side direction Y (in a segmented manner), wrinkles in the winding fixing strips 28 can be suppressed even when the length of the winding electrode body 20a along the long side direction Y is long. During battery manufacturing (e.g., the activation process described later) or in use, sometimes a pair of long sidewalls 12b of the battery 100 are clamped by a restraint mechanism, and the battery 100 is pressed from the long side direction Y. In this case, by suppressing wrinkles in the winding fixing strips 28, the thickness of the winding electrode body 20a can be suppressed (…). Figure 9B The length of the short side (X) is locally increased. This allows for uniform pressing of the wound electrode body 20a from the long side (Y), suppressing the application of excessive local pressure. Consequently, uneven reaction is less likely to occur during charging and discharging, thus suppressing dendrite formation.

[0078] Furthermore, to stabilize the charge-discharge characteristics of the battery 100, it is preferable to apply pressure to the flat portion 20f of the flat-shaped wound electrode body 20a through the battery casing 10. In this case, a relatively larger pressure is applied to the portion where the winding fixing strip 28 is attached compared to the portion where the winding fixing strip 28 is not attached. Consequently, in the long side direction Y, the electrolyte is less likely to move in the portion where the winding fixing strip 28 is attached. In particular, it is difficult to move in the vertical direction Z. This tendency is particularly evident in battery packs where multiple batteries 100 are arranged in the short side direction X and a load is applied from the short side direction X by a constraint mechanism. Therefore, as disclosed herein, by attaching multiple winding fixing strips 28 in a segmented manner, compared to attaching a single linear winding fixing strip, the diffusion of the electrolyte inside the wound electrode body 20a (the movement of the liquid during charge-discharge, especially the diffusion of the electrolyte in the vertical direction Z) can be relatively promoted. This allows for better (well-balanced) charge-discharge of the multiple wound electrode bodies 20a, 20b, and 20c. Therefore, the technology disclosed herein exhibits particularly excellent results.

[0079] The winding and fixing tape 28 preferably has a tape substrate portion and an adhesive layer formed on the surface of the tape substrate portion. As the tape substrate portion, for example, films made of resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyvinyl chloride, polypropylene (PP), polyarylate, polyurethane, polycarbonate, polyamide, polyimide (PI), polyphenylene sulfide (PPS), and polytetrafluoroethylene, or composites thereof, can be used. The adhesive layer is a layer containing an adhesive. As the adhesive, for example, rubber-based, silicone-based, acrylic, and acrylate adhesives can be used. Among these, adhesives containing acrylic and / or rubber-based adhesives are preferred.

[0080] The plurality of winding fixing tapes 28 are rectangles, each having a long side and a short side. The plurality of winding fixing tapes 28 are arranged such that the long side of each rectangle is along the long side direction Y. The lengths (long side direction Y, in other words, the length along the winding axis WL) Lx, Ly, Lz of the plurality of winding fixing tapes 28 can be approximately the same (e.g., the arithmetic mean of the distances Lx, Ly, Lz, within approximately ±50%, for example, within ±25%), or they can be different from each other. Similarly, the lengths (vertical direction Z, in other words, the length in the direction orthogonal to the winding axis WL) of the plurality of winding fixing tapes 28 can be approximately the same (e.g., the arithmetic mean of the distances Lx, Ly, Lz, within approximately ±50%, for example, within ±25%), or they can be different from each other. The lengths of the short sides of the winding fixing tapes 28 can also be 20 ± 10 mm each.

[0081] In the long side direction Y, when the length L1 of the positive electrode active material layer 22a is set to 100%, the ratio of the total length (Lx+Ly+Lz) of the plurality of winding fixing strips 28 is preferably 20-70%, more preferably 30-50%. By setting the total length to a predetermined ratio or higher, wrinkles caused by twisting during the application of the winding fixing strips 28 can be better suppressed. Furthermore, by setting the total length to a predetermined ratio or lower, excessively wide spacing D1, D2 between the winding fixing strips 28 can be prevented. This suppresses the peeling of the winding fixing strips 28 or the roll-up of the separator 26 that could cause wrinkles in the wound electrode body 20a. Therefore, uneven reaction during charging and discharging, dendrite formation, etc., can be prevented or suppressed to a high degree.

[0082] In the long Y direction, the spacing D1 and D2 between adjacent winding fixing strips 28 are preferably 30-105 mm, more preferably 60-90 mm. By setting the spacing D1 and D2 to a predetermined ratio or higher, wrinkles caused by twisting during the application of the winding fixing strips 28 can be better suppressed. Furthermore, by setting the spacing D1 and D2 to a predetermined ratio or lower, wrinkles caused by peeling of the winding fixing strips 28 or roll-up of the diaphragm 26 on the winding electrode body 20a can be suppressed. Therefore, uneven reaction and dendrite formation during charging and discharging can be prevented or suppressed to a high degree.

[0083] The electrolyte can be the same as before, without any particular limitation. For example, the electrolyte may be a non-aqueous electrolyte containing a non-aqueous solvent and a supporting electrolyte. Non-aqueous solvents may 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 in solid form (solid electrolyte) and integrated with the electrode assembly 20.

[0084] 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 As shown, the positive current collector 50 includes a first positive current collector 51 and a second positive current collector 52. The first positive current collector 51 and the second positive current collector 52 may also be made of the same type of metal as the positive current collector 22c, such as conductive metals like aluminum, aluminum alloy, nickel, and stainless steel.

[0085] Figure 10 It is a schematic representation Figure 2 A magnified cross-sectional view of the vicinity of the positive end 30. Figure 11 This is a schematic three-dimensional view of the sealing plate 14. Figure 12 It is Figure 11 A 3D view of the sealing plate turned upside down. Figure 12 This refers to the inner side (side) of the outer casing 12 of the sealing plate 14. For example... Figures 10-12As shown, the positive electrode first current collector 51 is mounted on the inner surface of the sealing plate 14. The positive electrode first current collector 51 has a first region 51a and a second region 51b. The positive electrode first current collector 51 can be formed by bending a single component, for example, through stamping, or by integrating multiple components together using welding. Here, the positive electrode first current collector 51 is fixed to the sealing plate 14 by riveting.

[0086] The first region 51a is located between the sealing plate 14 and the electrode assembly 20. The first region 51a extends along the long side direction Y. The first region 51a extends horizontally along the inner surface of the sealing plate 14. A positive electrode insulating member 70 is disposed between the sealing plate 14 and the first region 51a. The first region 51a is insulated from the sealing plate 14 by the positive electrode insulating member 70. The first region 51a is electrically connected to the positive terminal 30 by riveting. In the first region 51a, a through hole 51h is formed at a position corresponding to the terminal lead-out hole 18 of the sealing plate 14, extending in the vertical direction Z. The second region 51b is located between the short sidewall 12c of the outer casing 12 and the electrode assembly 20. The second region 51b extends from one end of the first region 51a in the long side direction Y ( Figure 10 The left end of the second region 51b extends toward the short sidewall 12c of the outer body 12. The second region 51b extends along the vertical direction Z.

[0087] The positive electrode second current collector 52 extends along the short sidewall 12c of the outer casing 12. For example... Figure 6 As shown, the second positive electrode current collector 52 has a current collector plate connecting portion 52a, an inclined portion 52b, and an electrode tab joining portion 52c. The current collector plate connecting portion 52a is the part that is electrically connected to the first positive electrode current collector 51. The current collector plate connecting portion 52a extends along the vertical direction Z. The current collector plate connecting portion 52a is arranged substantially perpendicular to the winding axis WL of the winding electrode bodies 20a, 20b, and 20c. A recess 52d with a thickness thinner than its surroundings is provided in the current collector plate connecting portion 52a. A through hole 52e extending in the short side direction X is provided in the recess 52d. A joining portion that joins with the first positive electrode current collector 51 is formed in the through hole 52e. The joining portion is, for example, a welded joining portion formed by welding such as ultrasonic welding, resistance welding, or laser welding. A fuse may also be provided in the second positive electrode current collector 52.

[0088] The tab connection portion 52c is a part attached to the positive electrode tab group 23 and electrically connected to the multiple positive electrode tabs 22t. For example... Figure 5 , Figure 6 As shown, the tab joint 52c extends along the vertical direction Z. The tab joint 52c is arranged substantially perpendicular to the winding axis WL of the winding electrode bodies 20a, 20b, and 20c. The surface of the tab joint 52c that connects to the plurality of positive electrode tabs 22t is arranged substantially parallel to the short sidewall 12c of the outer casing 12. Figure 4 As shown, a joint J is formed at the tab joint 52c to engage with the positive electrode tab assembly 23. The joint J is, for example, a welded joint formed by welding multiple positive electrode tabs 22t in an overlapping state using ultrasonic welding, resistance welding, laser welding, or the like. The welded joint positions the multiple positive electrode tabs 22t close to the side of the short side in the X direction of the wound electrode bodies 20a, 20b, and 20c. This allows for more appropriate bending of the multiple positive electrode tabs 22t, resulting in a stable formation. Figure 4 The positive electrode tab group 23 has a curved shape as shown.

[0089] The inclined portion 52b is the part that connects the lower end of the current collector plate connecting portion 52a to the upper end of the electrode tab connecting portion 52c. The inclined portion 52b is inclined relative to the current collector plate connecting portion 52a and the electrode tab connecting portion 52c. The inclined portion 52b connects the current collector plate connecting portion 52a and the electrode tab connecting portion 52c in the long side direction Y such that the current collector plate connecting portion 52a is located closer to the center side than the electrode tab connecting portion 52c. As a result, the housing space of the electrode body assembly 20 can be expanded, and the energy density of the battery 100 can be increased. The lower end of the inclined portion 52b (in other words, the end on the bottom wall 12a side of the outer casing 12) is preferably located below the lower end of the positive electrode tab assembly 23. As a result, multiple positive electrode tabs 22t can be bent more appropriately and stably formed. Figure 4 The positive electrode tab group 23 has a curved shape as shown.

[0090] The negative electrode current collector 60 forms a conductive path that electrically connects the negative electrode tab group 25, which consists of multiple negative electrode tabs 24t, to the negative terminal 40. For example... Figure 2 As shown, the negative current collector 60 includes a first negative current collector 61 and a second negative current collector 62. 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 current collector 24c, such as copper, copper alloy, nickel, stainless steel, or other conductive metals. The structure of the first negative current collector 61 and the second negative current collector 62 can be the same as that of the first positive current collector 51 and the second positive current collector 52 of the positive current collector 50.

[0091] like Figure 12 As shown, the negative electrode first current collector 61 has a first region 61a and a second region 61b. A negative electrode insulating member 80 is disposed between the sealing plate 14 and the first region 61a. The first region 61a is insulated from the sealing plate 14 by the negative electrode insulating member 80. In the first region 61a, a through hole 61h is formed at a position corresponding to the terminal lead-out hole 19 of the sealing plate 14, extending in the vertical direction Z. Figure 6As shown, the second negative electrode current collector 62 has: a current collector plate connecting portion 62a electrically connected to the first negative electrode current collector 61; an inclined portion 62b; and an electrode tab engaging portion 62c attached to the negative electrode tab assembly 25 and electrically connected to the plurality of negative electrode tabs 24t. The current collector plate connecting portion 62a has a recess 62d connected to the electrode tab engaging portion 62c. A through hole 62e extending in the short side direction X is provided in the recess 62d.

[0092] The positive electrode insulating component 70 is a component that insulates the sealing plate 14 from the positive electrode first current collector 51. It should be noted that the following detailed description uses the positive electrode insulating component 70 as an example, but the same structure can also be used for the negative electrode insulating component 80. The positive electrode insulating component 70 is made of a resin material that has resistance and electrical insulation to the electrolyte used and is elastically deformable. For example, it is preferably made of polyolefin resins such as polypropylene (PP), fluorinated resins such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), or polyphenylene sulfide (PPS).

[0093] like Figure 2 As shown, the positive electrode insulating component 70 has a base portion 70a and a plurality of protrusions 70b. The base portion 70a and the protrusions 70b are integrally formed. The positive electrode insulating component 70 is a one-piece molded product made of the resin material described above. Therefore, compared with the case where the base portion 70a and the protrusions 70b are separate components, the number of components used can be reduced, and cost reduction can be achieved. In addition, the positive electrode insulating component 70 can be prepared more simply.

[0094] The substrate 70a is located in the vertical direction Z, between the sealing plate 14 and the first region 51a of the positive electrode first current collector 51. The substrate 70a extends horizontally along the first region 51a of the positive electrode first current collector 51. Figure 12 As shown, the base portion 70a has a through hole 70h extending through in the vertical direction Z. The through hole 70h is formed at a position corresponding to the terminal lead-out hole 18 of the sealing plate 14.

[0095] Multiple protrusions 70b protrude toward the electrode assembly 20 compared to the base portion 70a. For example... Figure 12 As shown, in the long side direction Y, multiple protrusions 70b are provided on the central side of the sealing plate 14, which is closer to the base portion 70a. Figure 12 The position is on the right side. Multiple protrusions 70b are arranged in the short-side direction X. For example... Figure 3 As shown, the multiple protrusions 70b are formed in a roughly U-shaped cross section. These protrusions 70b face the curved portions 20r of the wound electrode bodies 20a, 20b, and 20c that constitute the electrode body assembly 20. This prevents damage to the end faces of the wound electrode bodies 20a, 20b, and 20c from being pressed by the protrusions 70b.

[0096] 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 more reliably face the protrusions 70b, thus better realizing the technical effects disclosed herein. Furthermore, in the insertion process described later, the wound electrode bodies 20a, 20b, and 20c can be made to a balanced and good contact with the protrusions 70b. 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.

[0097] 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 with respect to 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. The negative electrode insulating member 80, like the positive electrode insulating member 70, has a plurality of protrusions 80b and a base portion 80a disposed between the sealing plate 14 and the negative electrode first current collector 61.

[0098] The battery 100 preferably includes both a positive electrode insulating component 70 and a negative electrode insulating component 80. Therefore, even if vibration or impact is applied during use of the battery 100, it is easy to keep the electrode assembly 20 and the sealing plate 14 parallel. Figure 2 The state is maintained. In addition, in the insertion process described later, the electrode assembly 20 can be better (e.g., in a balanced and good manner in the long side direction Y) abutted, and the electrode assembly 20 can be stably pressed by the protrusion 70b and inserted into the outer body 12.

[0099] <Manufacturing Method of Battery 100>

[0100] The manufacturing method of battery 100 is characterized by using the aforementioned wound electrode bodies 20a, 20b, and 20c. Other manufacturing processes can be the same as before. Battery 100 can be manufactured by the following method: in addition to the electrode body assembly 20 (wound electrode bodies 20a, 20b, and 20c), a battery casing 10 (outer body 12 and sealing plate 14), electrolyte, positive terminal 30, negative terminal 40, positive current collector 50 (positive first current collector 51 and positive second current collector 52), negative current collector 60 (negative first current collector 61 and negative second current collector 62), positive insulating component 70, and negative insulating component 80 are prepared, sequentially including, for example, a first mounting step, a second mounting step, an insertion step, a sealing step, and an activation step. Furthermore, the manufacturing method disclosed herein may further include other steps at any stage.

[0101] In the first installation process, the fabrication Figure 11 , Figure 12The first assembly is as shown. Specifically, firstly, a positive terminal 30, a positive first current collector 51, a positive insulating component 70, a negative terminal 40, a negative first current collector 61, and a negative insulating component 80 are installed on the sealing plate 14.

[0102] The positive terminal 30, the first positive current collector 51, and the positive insulating component 70 are fixed to the sealing plate 14, for example, by riveting. Figure 10 As shown, the riveting process involves clamping a washer 90 between the outer surface of the sealing plate 14 and the positive terminal 30, and then clamping a positive electrode insulating member 70 between the inner surface of the sealing plate 14 and the positive electrode first current collector 51. It should be noted that the washer 90 can be made of the same material as the positive electrode insulating member 70. Specifically, before riveting, the positive terminal 30 is inserted sequentially from above the sealing plate 14 into the through hole 90h of the washer 90, the terminal lead-out hole 18 of the sealing plate 14, the through hole 70h of the positive electrode insulating member 70, and the through hole 51h of the positive electrode first current collector 51, causing it to protrude downwards from the sealing plate 14. Then, the portion of the positive terminal 30 that protrudes downwards from the sealing plate 14 is riveted by applying a compressive force relative to the vertical direction Z. Thus, at the front end of the positive terminal 30 ( Figure 2 The lower end of the part forms a riveting part 30c.

[0103] Through this riveting process, the washer 90, sealing plate 14, positive electrode insulating component 70, and positive electrode first current collector 51 are integrally fixed to the sealing plate 14, and the terminal lead-out hole 18 is sealed. It should be noted that the riveting part 30c can also be welded to the positive electrode first current collector 51. This further improves the conductivity reliability.

[0104] The fixing of the negative terminal 40, the first negative current collector 61, and the negative 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 washer, the terminal lead-out hole 19 of the sealing plate 14, the through hole of the negative insulating member 80, and the through hole of the first negative current collector 61, causing it to protrude downwards from the sealing plate 14. Then, the portion of the negative terminal 40 that protrudes downwards from the sealing plate 14 is riveted by applying a compressive force relative to the vertical direction Z. As a result, at the front end of the negative terminal 40 ( Figure 2 The lower end of the part forms a riveting part 40c.

[0105] 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. It should be noted that the material of the external insulating component 92 can also be the same as that of the positive electrode insulating component 70. In addition, the positive electrode external conductive component 32 and the negative electrode external conductive component 42 can also be installed after the insertion process (for example, after sealing the injection hole 15).

[0106] In the second installation step, the first assembly produced in the first installation step is used to manufacture... Figure 5 The second merged product as shown. Specifically, firstly, as Figure 6 As shown, three wound electrode bodies 20a, each equipped with a positive second current collector 52 and a negative second current collector 62, are prepared and arranged as wound electrode bodies 20a, 20b, and 20c in the short side direction X. At this time, the wound electrode bodies 20a, 20b, and 20c can all be arranged with the positive second current collector 52 on one side in the long side direction Y. Figure 5 (on the left side) and the negative electrode second current collector 62 is disposed on the other side in the long side direction Y ( Figure 5 They are arranged side by side on the right side.

[0107] Next, as Figure 4 As shown, with the multiple positive electrode tabs 22t bent, the first positive electrode current collector 51 (specifically, the second region 51b) fixed to the sealing plate 14 is joined to the second positive electrode current collector 52 (specifically, the current collector plate connection portion 52a) of the wound electrode bodies 20a, 20b, and 20c, respectively. Similarly, with the multiple negative electrode tabs 24t of the negative electrode tab group 25 bent, the first negative electrode current collector 61 fixed to the sealing plate 14 is joined to the second negative electrode current collector 62 of the wound electrode bodies 20a, 20b, and 20c, respectively. As a joining method, welding methods such as ultrasonic welding, resistance welding, and laser welding can be used. Welding based on high-energy lines such as lasers is particularly preferred. Through this welding process, joint portions are formed in the recesses 52d of the second positive electrode current collector 52 and the recesses 62d of the second negative electrode current collector 62, respectively.

[0108] During the insertion process, the electrode assembly 20, which is integral with the sealing plate 14, is housed in the internal space of the outer casing 12. Figure 13This is a schematic cross-sectional view illustrating the insertion process. Specifically, first, for example, an insulating resin sheet made of a resin material such as polyethylene (PE) is bent into a bag or box shape to prepare the 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, or even 2-3 kg, then... Figure 13 As shown, the electrode assembly 20 can be 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 (by placing the outer body 12 laterally).

[0109] 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 the protrusions 80b of the negative electrode insulating member 80. 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.

[0110] The positive electrode tab assembly 23 and / or the negative electrode tab assembly 25 have gaps that allow them to move in a direction intersecting the protruding direction (typically the vertical Z direction). Therefore, after the electrode assembly 20 is inserted into the outer casing 12, if the outer casing 12 is erected with the sealing plate 14 positioned above, 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.

[0111] 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 by welding, such as 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.

[0112] In the activation process, firstly, the long sidewall 12b of the sealed battery 100 is clamped and pressed using a constraint mechanism. Then, the pressed battery 100 is subjected to, as before, sequentially, for example, initial charging, aging treatment, and self-discharge testing. During initial charging, an external power source is connected between the positive terminal 30 and the negative terminal 40 to charge the battery 100 to a specified voltage. During aging treatment, for example, the battery 100 is placed in a constant temperature bath set to specified temperature conditions (e.g., 40~60°C) and maintained for a specified time (e.g., approximately 10~15 hours). During self-discharge testing, for example, firstly, the aged battery 100 is adjusted to a specified depth of charge in a room temperature range (e.g., 15~25°C). Then, the battery 100 is left to self-discharge for a certain period, and the voltage drop is measured. Next, based on the measured voltage drop, it is checked whether an internal short circuit has occurred in the battery 100 (whether it is a qualified product).

[0113] As described above, battery 100 can be manufactured.

[0114] 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 (PHVs), hybrid electric vehicles (HVs), and electric vehicles (EVs). Battery 100 can be used in the construction of battery packs.

[0115] The present invention has been described above with reference to several embodiments, but these embodiments are merely examples. The present invention can also 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 technologies 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 omitted.

[0116] For example, the battery 100 of the above embodiment includes an electrode assembly 20 having multiple wound electrode bodies 20a, 20b, and 20c. The wound electrode bodies 20b and 20c have the same structure as the wound electrode body 20a. However, this is not a limitation. The wound electrode bodies 20b and 20c may also have different structures than the wound electrode body 20a. For example, the number of multiple winding fixing tapes 28 attached to the wound electrode bodies 20a, 20b, and 20c may also be different. Furthermore, the positions where the multiple winding fixing tapes 28 are attached to the wound electrode bodies 20a, 20b, and 20c may also be different.

[0117] Figure 14AThis is a schematic front view of the first wound electrode body 120a. Figure 14B This is a schematic front view showing the second wound electrode body 120b. A modified battery has a first wound electrode body 120a and a second wound electrode body 120b. An odd number of winding fixing tapes 28 are attached to the outer surface of the first wound electrode body 120a. An even number of winding fixing tapes 28 are attached to the outer surface of the second wound electrode body 120b. The number of winding fixing tapes 28 differs between the first wound electrode body 120a and the second wound electrode body 120b.

[0118] Furthermore, in the first wound electrode body 120a and the second wound electrode body 120b, the positions of the winding fixing tape 28 are staggered in the long side direction Y. This helps to suppress localized increases in the thickness of the electrode body assembly (first wound electrode body 120a and second wound electrode body 120b). Additionally, it allows for balanced and efficient charging and discharging of the wound electrode bodies 120a and 120b. In the long side direction Y, Figure 14A The total length of the multiple winding fixing strips 28 of the first winding electrode body 120a and Figure 14B The total length (Lxa+Lya+Lza+Lxb+Lyb) of the multiple winding fixing strips 28 of the second winding electrode body 120b can also be approximately the same as the length L1 of the positive electrode active material layer of the first winding electrode body 120a and the second winding electrode body 120b (which allows for manufacturing errors).

[0119] This application claims priority to Japanese Patent Application No. 2020-186228, filed on November 9, 2020, the entire contents of which are incorporated herein by reference.

Claims

1. A battery, wherein, The battery includes: an electrode body in which a positive electrode having a positive electrode active material layer and a negative electrode having a negative electrode active material layer are stacked with a belt-shaped separator interposed therebetween; and a plurality of winding fixing tapes attached to the separator wound at an outermost circumference of the electrode body, one end portion of the electrode body in a first direction has a positive electrode tab provided to the positive electrode, the positive electrode tab is bent and connected to a positive electrode current collecting member, the other end portion of the electrode body in the first direction has a negative electrode tab provided to the negative electrode, the negative electrode tab is bent and connected to a negative electrode current collecting member, a length of the positive electrode active material layer in the first direction is 15 cm or more, the plurality of winding fixing tapes are respectively attached to end portions in a longitudinal direction of the belt-shaped separator and are located at end portions of an outer surface of the electrode body, the plurality of winding fixing tapes are respectively rectangular shapes having a long side and a short side, the plurality of winding fixing tapes are respectively attached to the outer surface of the electrode body at intervals in the first direction with the long sides of the rectangular shapes oriented in the first direction, intervals between adjacent ones of the plurality of winding fixing tapes are 105 mm or less, the electrode body has a flat portion, in a state of the electrode body, a dimension of each of the plurality of winding fixing tapes in a direction orthogonal to the first direction is smaller than a dimension of the flat portion in the direction orthogonal to the first direction, and in the first direction, the plurality of winding fixing tapes are all distanced from end portions of the electrode body in the first direction among the outer surface of the electrode body.

2. The battery according to claim 1, wherein the electrode body is plural, the plurality of winding fixing tapes are respectively attached to the plural electrode bodies.

3. The battery according to claim 1, wherein the battery includes a positive electrode tab group including the plurality of positive electrode tabs and a negative electrode tab group including the plurality of negative electrode tabs.

4. The battery according to any one of claims 1 to 3, wherein in the first direction, a proportion of a total length of the plurality of winding fixing tapes to a length of the positive electrode active material layer is 20% or more and 70% or less when the length of the positive electrode active material layer is set to 100%.

5. The battery according to any one of claims 1 to 3, wherein intervals between adjacent ones of the plurality of winding fixing tapes are 30 mm or more and 105 mm or less.

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