battery

Abstract

The present invention relates to a battery. A battery (100) disclosed herein is provided with: a case having a bottom wall and an opening facing the bottom wall; a sealing plate sealing the opening of the case; and one or more wound electrode bodies (20a) each of which is formed by laminating a strip-shaped positive electrode having a positive active material layer and a strip-shaped negative electrode having a negative active material layer with a strip-shaped separator and winding around a winding axis. The wound electrode body (20a) is housed in the case in such a manner that the winding axis is along the bottom wall of the case. In the direction of the winding axis of the wound electrode body (20a), the length (L1) of the positive active material layer is 15 cm or more. On the outer surface of the wound electrode body (20a), a plurality of winding fixing tapes (28) are attached at intervals in the direction of the winding axis.

Description

TECHNICAL FIELD

[0001] The present application relates to a battery. BACKGROUND

[0002] In the past, a battery having a jelly-roll electrode body in which a strip-shaped positive electrode having a positive active material layer on a positive current collector and a strip-shaped negative electrode having a negative active material layer on a negative current collector are laminated with a strip-shaped separator and are wound around a winding axis has been known (WO2015 / 146076, Japanese Patent Application Publication No. 2012-69290).

[0003] For example, in WO2015 / 146076, a lithium ion secondary battery in which a winding fixing tape is attached to a winding terminal portion of a jelly-roll electrode body and is fixed to the jelly-roll electrode body itself in order to prevent winding relaxation of the jelly-roll electrode body is disclosed. SUMMARY

[0004] In a high-capacity battery used for a vehicle or the like, the size of the jelly-roll electrode body becomes large. If the size of the jelly-roll electrode body becomes large, the winding fixing tape for preventing winding relaxation also becomes long. If the winding fixing tape becomes long, it is easily twisted at the time of pulling out, and wrinkles are easily generated at the time of being attached to the jelly-roll electrode body. If wrinkles are generated in the winding fixing tape, steps are formed in the jelly-roll electrode body, and the thickness locally becomes large. Due to this, in the process of manufacturing the battery or at the time of use, the portion of the wrinkles is pressed with a strong force at the time of applying pressure to the jelly-roll electrode body. As a result, unevenness in the reaction of charge and discharge is likely to be generated, and further, lithium metal (dendrite) is likely to be precipitated.

[0005] The present application has been made in view of the above circumstances, and has an object to provide a battery in which wrinkles are not easily generated in a winding fixing tape and unevenness in the reaction of charge and discharge is suppressed.

[0006] According to the present application, there is provided a battery including: an exterior body having a bottom wall and an opening facing the bottom wall; a sealing plate sealing the opening of the exterior body; and one or more jelly-roll electrode bodies in which a strip-shaped positive electrode having a positive active material layer and a strip-shaped negative electrode having a negative active material layer are laminated with a strip-shaped separator and are wound around a winding axis. The jelly-roll electrode body is housed in the exterior body in such a manner that the winding axis is along the bottom wall of the exterior body. The length of the positive active material layer in the direction of the winding axis of the jelly-roll electrode body is 15 cm or more. A plurality of winding fixing tapes are attached to the outer surface of the jelly-roll electrode body at intervals along the direction of the winding axis.

[0007] In the above-described battery, a plurality of winding fixing bands are attached to the outer surface of the winding electrode body at intervals. Thus, even in the case where the length in the winding axis direction of the winding electrode body is long (specifically, the length of the positive electrode active material layer is 15 cm or more), compared with the case where one winding fixing band is attached in a linear shape, the generation of wrinkles in the winding fixing band can be relatively suppressed. As a result, reaction unevenness is less likely to occur at the time of charge and discharge, and further, the generation of dendrites can be suppressed.

[0008] In a preferred embodiment of the battery disclosed herein, the above-described winding electrode body is a plurality. In the case where the winding electrode body is a plurality, the influence of wrinkles becomes large in particular. Therefore, the application of the technology disclosed herein is particularly effective.

[0009] In a preferred embodiment of the battery disclosed herein, there are provided: a positive tab group including a plurality of positive tabs that protrude from one end portion of the winding electrode body in the winding axis direction thereof and that are electrically connected to the positive electrode; and a negative tab group that protrudes from the other end portion of the winding electrode body in the winding axis direction thereof and that is electrically connected to the negative electrode. In such a structure, the length in the winding axis direction of the winding electrode body becomes long, and wrinkles are likely to occur in the winding fixing band. Therefore, the application of the technology disclosed herein is particularly effective.

[0010] In a preferred embodiment of the battery disclosed herein, the positive tab group and the negative tab group are eccentrically arranged toward the sealing plate side in a direction perpendicular to the sealing plate. With such a structure, the conduction path to the terminal can be shortened.

[0011] In a preferred embodiment of the battery disclosed herein, a plurality of the winding fixing bands are arranged on a straight line that links the positive tab group and the negative tab group.

[0012] In a preferred embodiment of the battery disclosed herein, when the length of the positive electrode active material layer is taken as 100% in the winding axis direction, the proportion of the total length of the plurality of winding fixing bands is 20% or more and 70% or less. With such a structure, reaction unevenness, the generation of dendrites, and the like at the time of charge and discharge can be prevented or highly suppressed.

[0013] In a preferred embodiment of the battery disclosed herein, the interval between adjacent ones of the plurality of winding fixing bands is 30 mm or more and 105 mm or less. With such a structure, reaction unevenness, the generation of dendrites, and the like at the time of charge and discharge can be prevented or highly suppressed. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a perspective view schematically showing a battery of an embodiment.

[0015] Figure 2 is a schematic longitudinal sectional view along the line II-II of Figure 1

[0016] Figure 3 is a schematic longitudinal sectional view along the line III-III of Figure 1

[0017] Figure 4 is a schematic transverse sectional view along the line IV-IV of Figure 1

[0018] Figure 5 is a perspective view schematically showing the electrode body group mounted to the closure plate.

[0019] Figure 6 is a perspective view schematically showing the electrode body to which the positive second current collecting portion and the negative second current collecting portion are mounted.

[0020] Figure 7 is a schematic view showing the structure of the wound electrode body.

[0021] Figure 8 is a partial enlarged sectional view schematically showing the upper end portion of the wound electrode body of Figure 3

[0022] Figure 9A is a side view schematically showing the wound electrode body of Figure 7

[0023] Figure 9B is a front view schematically showing the wound electrode body of Figure 7

[0024] Figure 10 is a partial enlarged sectional view schematically showing the vicinity of the positive terminal of Figure 2

[0025] Figure 11 is a perspective view schematically showing the closure plate to which the positive terminal, the negative terminal, the positive first current collecting portion, the negative first current collecting portion, the positive insulating member, and the negative insulating member are mounted.

[0026] Figure 12 is a perspective view of the closure plate of Figure 11 turned upside down.

[0027] Figure 13 is a schematic sectional view illustrating an insertion process of a battery of an embodiment.

[0028] Figure 14A is a partial enlarged sectional view schematically showing the first wound electrode body of the battery of the modification example. Figure 9B is a corresponding view.​​​​​​​

[0029] Figure 14B is a schematic view of a second wound electrode body of a battery of a modification example. Figure 9B Corresponding view.

[0030] Explanation of reference numerals

[0031] 12 outer case

[0032] 14 sealing plate

[0033] 20 electrode body group

[0034] 20a, 20b, 20c wound electrode body

[0035] 20f flat portion

[0036] 20r curved portion

[0037] 23 positive electrode tab group

[0038] 25 negative electrode tab group

[0039] 28 wound fixing tape

[0040] 100 battery DETAILED DESCRIPTION

[0041] Hereinafter, several preferred embodiments of the technology disclosed herein will be described with reference to the drawings. Note that matters other than those specifically mentioned in this specification and matters required for the implementation of the present application (for example, general structures and manufacturing processes of batteries that are not characteristic of the present application) can be understood as design matters of those skilled in the art based on the existing technology in the field. The present application can be implemented based on the content disclosed in this specification and technical common sense in the field. Note that the expression "A to B" indicating a range in this specification includes the meaning of A or more and B or less, and includes the meaning of "preferably greater than A" and "preferably less than B".

[0042] Note that in this specification, "battery" is a term referring to all power storage devices capable of taking out electric power, and is a concept including primary batteries and secondary batteries. In addition, in this specification, "secondary battery" is a term referring to all power storage devices capable of repeated charge and discharge, and is a concept including so-called accumulators (chemical batteries) such as lithium-ion secondary batteries, nickel-hydrogen batteries, and the like, and capacitors (physical batteries) such as electric double layer capacitors.

[0043] <Battery 100>

[0044] Figure 1 is a perspective view of the battery 100. Figure 2 is a schematic longitudinal sectional view along the II-II line of Figure 1 .Figure 3 is a schematic longitudinal sectional view along the III-III line of Figure 1 Figure 4 is a schematic transverse sectional view along the IV-IV line of Figure 1 In the following description, the reference signs L, R, F, Rr, U, D in the drawings represent left, right, front, rear, upper, and lower, and the reference signs X, Y, Z in the drawings represent a short side direction, a long side direction orthogonal to the short side direction, and an up-down direction of the battery 100, respectively. However, these are merely directions for convenience of explanation, and the battery 100 is not limited in the manner of arrangement.

[0045] As shown in Figure 2 , the battery 100 includes a battery case 10, an electrode body group 20, a positive electrode terminal 30, a negative electrode terminal 40, a positive electrode current collecting portion 50, a negative electrode current collecting portion 60, a positive electrode insulating member 70, and a negative electrode insulating member 80. As will be described later in detail, the electrode body group 20 includes wound electrode bodies 20a, 20b, and 20c (see Figure 3 ). Although not shown, the battery 100 also includes an electrolyte. The battery 100 is a lithium ion secondary battery. The battery 100 is characterized by including the wound electrode bodies 20a, 20b, and 20c, and the structure other than this can be the same as in the past.

[0046] The battery case 10 is a frame that houses the electrode body group 20. The battery case 10 has a flat and bottomed rectangular parallelepiped shape (square) shape in the outer shape. The material of the battery case 10 can be the same as that used in the past, and is not particularly limited. The battery case 10 is preferably made of metal, and more preferably made of, for example, aluminum, an aluminum alloy, iron, an iron alloy, or the like. As shown in Figure 2 , the battery case 10 includes an outer body 12 having an opening 12h, and a sealing plate (cover) 14 that plugs the opening 12h.

[0047] As shown in Figure 1 , the outer body 12 includes a bottom wall 12a, a pair of long side walls 12b extending from the bottom wall 12a and facing each other, and a pair of short side walls 12c extending from the bottom wall 12a and facing each other. The bottom wall 12a is substantially rectangular. The bottom wall 12a faces the opening 12h. The short side walls 12c have a smaller area than the long side walls 12b. The sealing plate 14 is attached to the outer body 12 in such a manner as to plug the opening 12h of the outer body 12. The sealing plate 14 faces the bottom wall 12a of the outer body 12. The sealing plate 14 is substantially rectangular when viewed from above. The battery case 10 is integrated by joining (for example, welding) the sealing plate 14 to the outer body 12 at the periphery of the opening 12h of the outer body 12. The battery case 10 is hermetically sealed (closed).

[0048] As shown in Figure 2 , the battery case 10 includes an outer body 12 having an opening 12h, and a sealing plate (cover) 14 that plugs the opening 12h.As shown, the sealing plate 14 is provided with a liquid injection hole 15, a gas discharge valve 17, and two terminal lead-out holes 18, 19. The liquid injection hole 15 is used to inject electrolyte after the sealing plate 14 is assembled to the outer body 12. The liquid injection hole 15 is sealed by a sealing member 16. The gas discharge valve 17 is configured to break when the pressure inside the battery case 10 becomes a prescribed value or more, and discharge gas inside the battery case 10 to the outside. The terminal lead-out holes 18, 19 are formed at both ends in the long direction Y of the sealing plate 14. The terminal lead-out holes 18, 19 pass through the sealing plate 14 in the up-down direction Z. The terminal lead-out holes 18, 19 each have an inner diameter of a size that allows the positive and negative terminal 30, 40 to be inserted before the sealing plate 14 is assembled (before riveting processing).

[0049] The positive and negative terminals 30, 40 are each fixed to the sealing plate 14. The positive terminal 30 is disposed on one side (left side) of the long direction Y of the sealing plate 14. The negative terminal 40 is disposed on the other side (right side) of the long direction Y of the sealing plate 14. As shown, the positive and negative terminals 30, 40 are exposed on the surface outside the sealing plate 14. As shown, the positive and negative terminals 30, 40 are inserted through the terminal lead-out holes 18, 19 and extend from the inside to the outside of the sealing plate 14. Here, the positive and negative terminals 30, 40 are riveted to the peripheral portion of the terminal lead-out holes 18, 19 of the sealing plate 14 by riveting processing. Rivet portions 30c, 40c are formed at the end portion (lower end portion) of the positive and negative terminals 30, 40 on the side of the outer body 12. Figure 1 Figure 2 Figure 1 Figure 2 Figure 1 Figure 2 Figure 2

[0050] As shown, the positive terminal 30 is electrically connected to the positive electrode 22 (see FIG. 2) of the electrode body group 20 via the positive current collecting portion 50 inside the outer body 12. The negative terminal 40 is electrically connected to the negative electrode 24 (see FIG. 2) of the electrode body group 20 via the negative current collecting portion 60 inside the outer body 12. The positive terminal 30 is insulated from the sealing plate 14 by the positive insulating member 70 and the gasket 90. The negative terminal 40 is insulated from the sealing plate 14 by the negative insulating member 80 and the gasket 90. Figure 2 Figure 7 Figure 7

[0051] ​​​​​​​​​​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.

[0052] 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.

[0053] 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.

[0054] 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 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.

[0055] like Figure 3As shown, the wound electrode body 20a has a pair of curved portions (R portions) 20r facing the bottom wall 12a of the exterior body 12 and the sealing plate 14, and a flat portion 20f linking the pair of curved portions 20r and facing the long side wall 12b of the exterior body 12. On one side (the upper side) of the curved portion 20r, the positive electrode first current collecting portion 51, the negative electrode first current collecting portion 61, the positive electrode insulating member 70, the negative electrode insulating member 80, and the like are interposed, and the curved portion 20r indirectly faces the sealing plate 14. On the other side (the lower side) of the curved portion 20r, the electrode body holder 29 is interposed, and the curved portion 20r indirectly faces the bottom wall 12a. Figure 3 Figure 3

[0056] Figure 7 is a schematic view 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 interposed therebetween, and are wound around the winding axis WL. The wound electrode body 20a has a flat shape. The wound electrode body 20a is particularly preferably in such a flat shape. Figure 8 is a partially enlarged cross-sectional view schematically showing the upper end portion of the wound electrode body 20a. Figure 8 shows a cross section of the wound electrode body 20a in a direction orthogonal to the winding axis WL. Note that in Figure 8 , the positive electrode tab group 23 and the negative electrode tab group 25 described later are omitted from the drawing. Figure 9A is a side view schematically showing the wound electrode body 20a. Figure 9A shows a side surface (end surface) of the wound electrode body 20a in a direction orthogonal to the winding axis WL. Figure 9B is a front view schematically showing the wound electrode body 20a. Figure 9B shows a side surface of the wound electrode body 20a in a direction along the winding axis WL.

[0057] As shown in Figure 7 , the positive electrode 22 has a positive electrode current collector 22c, and a positive electrode active material layer 22a and a positive electrode protective layer 22p fixed to at least one surface of the positive electrode current collector 22c. However, the positive electrode protective layer 22p is not essential, and can be omitted in other embodiments. The positive electrode current collector 22c is strip-shaped. The positive electrode current collector 22c is composed of, for example, an electrically conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel. The positive electrode current collector 22c is a metal foil, specifically an aluminum foil, in this embodiment.

[0058] A plurality of positive electrode tabs 22t are provided at one end portion of the positive electrode current collector 22c in the long direction Y (the left end portion in Figure 7 . The plurality of positive electrode tabs 22t are directed to one side in the long direction Y (the negative electrode side in Figure 7 ​​The 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 portions 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.

[0059] like Figure 4 As shown, multiple positive electrode tabs 22t are located at one end in the long side direction Y ( Figure 4 The positive electrode tabs 22t are stacked at their left ends to form a positive electrode tab assembly 23. 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.

[0060] 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 greater than that 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.

[0061] 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.

[0062] like Figure 7 As shown, the positive electrode protective layer 22p is disposed in the boundary portion 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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 diaphragm 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.

[0072] Multiple winding fixing tapes 28 are attached to the winding end 26e of the diaphragm 26 (see reference). Figure 9B Multiple winding and fixing tapes 28 are attached to the outer surface of the wound electrode body 20a. The multiple winding and 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 20-70 mm, more preferably 25-45 mm. 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.

[0073] 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.

[0074] 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.

[0075] By attaching multiple winding fixing tapes 28 spaced apart at intervals D1 and D2 along the long side direction Y (in a segmented manner), wrinkles in the winding fixing tapes 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 tapes 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.

[0076] In addition, in order to stabilize the charge-discharge characteristics of the battery 100, it is preferable for the flat portion 20f of the flat wound electrode body 20a to be pressed by the battery case 10. At this time, a relatively large pressure is applied to the portion to which the winding fixing tape 28 is attached, as compared to the portion to which the winding fixing tape 28 is not attached. Thus, in the lengthwise direction Y, the electrolyte is less likely to move in the portion to which the winding fixing tape 28 is attached. In particular, the electrolyte is less likely to move in the upward-downward direction Z. This tendency is particularly noticeable in a battery pack in which a plurality of batteries 100 are arranged in the short side direction X and a load is applied in the short side direction X by a restraining mechanism. Therefore, by attaching a plurality of winding fixing tapes 28 separately, as in the technology disclosed herein, the diffusion of the electrolyte inside the wound electrode body 20a (the movement of the liquid during charge-discharge, and in particular the diffusion of the electrolyte in the upward-downward direction Z) can be promoted relatively as compared to the case in which one winding fixing tape in the form of a line is attached. Thus, the plurality of wound electrode bodies 20a, 20b, 20c can be charged and discharged more favorably (more balanced). Therefore, the technology disclosed herein exhibits particularly excellent effects.

[0077] The winding fixing tape 28 preferably has a tape base material portion and an adhesive layer formed on the surface of the tape base material portion. As the tape base material portion, for example, a resin film such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyvinyl chloride, polypropylene (PP), polyarylate, polyurethane, polycarbonate, polyamide, polyimide (PI), polyphenylene sulfide (PPS), polytetrafluoroethylene, or a composite thereof, or the like can be used. The adhesive layer is a layer containing an adhesive. As the adhesive, for example, an adhesive such as a rubber-based adhesive, a silicone-based adhesive, an acrylic adhesive, an acrylate-based adhesive, or the like can be used. Among these, an adhesive containing an acrylic-based adhesive and / or a rubber-based adhesive is preferable.

[0078] The plurality of winding fixing tapes 28 are each rectangular having a long side and a short side. The plurality of winding fixing tapes 28 are each arranged with the long side of the rectangle in the lengthwise direction Y. The lengths (lengths in the lengthwise direction Y, in other words, lengths in the direction along the winding axis WL) Lx, Ly, Lz of the long sides of the plurality of winding fixing tapes 28 can be substantially the same (for example, within about ±50%, for example, within ±25% of the arithmetic mean of the lengths Lx, Ly, Lz), or can be different from each other. In addition, the lengths (lengths in the upward-downward direction Z, in other words, lengths in the direction orthogonal to the winding axis WL) of the short sides of the plurality of winding fixing tapes 28 can be substantially the same (for example, within about ±50%, for example, within ±25% of the arithmetic mean of the lengths Lx, Ly, Lz), or can be different from each other. The lengths of the short sides of the winding fixing tapes 28 can each be 20 ± 10 mm.

[0079] 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.

[0080] In the long side direction Y, the spacing D1 and D2 between adjacent winding fixing strips 28 are preferably 30 to 105 mm, more preferably 60 to 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.

[0081] 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.

[0082] 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.

[0083] 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... Figure 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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 properties against 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).

[0091] 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.

[0092] 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.

[0093] 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, a plurality of 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.

[0094] The number of the protrusions 70b is the same as the number of the wound electrode bodies 20a, 20b, 20c that constitute the electrode body group 20. That is, three. Thereby, the wound electrode bodies 20a, 20b, 20c and the protrusions 70b can be more reliably faced, and the technical effects disclosed herein can be more effectively exerted. Further, in the insertion process described later, the wound electrode bodies 20a, 20b, 20c and the protrusions 70b can be in good balance abutment. However, the number of the protrusions 70b can be different from the number of the electrode bodies that constitute the electrode body group 20, and can be one, for example.

[0095] As shown in FIG. 1, the positive electrode insulating member 70 is disposed symmetrically with respect to the center CL of the electrode body group 20 in the longitudinal direction Y. The positive electrode insulating member 70 has a plurality of protrusions 70b and a base portion 70a disposed between the sealing plate 14 and the positive electrode first current collector 61. Figure 2 As shown in FIG. 1, the positive electrode insulating member 70 is disposed symmetrically with respect to the center CL of the electrode body group 20 in the longitudinal direction Y. The positive electrode insulating member 70 has a plurality of protrusions 70b and a base portion 70a disposed between the sealing plate 14 and the positive electrode first current collector 61.

[0096] The battery 100 preferably has both the positive electrode insulating member 70 and the negative electrode insulating member 80. Thereby, even if vibration, impact, or the like is applied at the time of use of the battery 100, the electrode body group 20 and the sealing plate 14 can be easily maintained in a state in which they are parallel (FIG. 1). Figure 2 Further, in the insertion process described later, the wound electrode bodies 20a, 20b, 20c and the protrusions 70b can be in good balance abutment (for example, in the longitudinal direction Y), and the electrode body group 20 can be stably pressed by the protrusions 70b and inserted into the outer case 12.

[0097] <Method of manufacturing the battery 100>

[0098] The method of manufacturing the battery 100 is characterized in that the above-described wound electrode bodies 20a, 20b, 20c are used. The manufacturing process other than this can be the same as in the past. The battery 100 can be manufactured by a manufacturing method that, in addition to the electrode body group 20 (the wound electrode bodies 20a, 20b, 20c), prepares the above-described battery case 10 (the outer case 12 and the sealing plate 14), the electrolyte, the positive electrode terminal 30, the negative electrode terminal 40, the positive electrode current collector 50 (the positive electrode first current collector 51 and the positive electrode second current collector 52), the negative electrode current collector 60 (the negative electrode first current collector 61 and the negative electrode second current collector 62), the positive electrode insulating member 70, and the negative electrode insulating member 80, and sequentially includes, for example, a first mounting process, a second mounting process, an insertion process, a sealing process, and an activation process. Further, the manufacturing method disclosed herein can further include other processes at any stage.

[0099] In the first mounting process, the positive electrode current collector 50 and the negative electrode current collector 60 are mounted to the outer case 12. Figure 11 Figure 12 ​The first assembly is shown. Specifically, first, the positive electrode terminal 30, the positive electrode first current collecting portion 51, the positive electrode insulating member 70, the negative electrode terminal 40, the negative electrode first current collecting portion 61, and the negative electrode insulating member 80 are attached to the sealing plate 14.

[0100] The positive electrode terminal 30, the positive electrode first current collecting portion 51, and the positive electrode insulating member 70 are fixed to the sealing plate 14, for example, by a riveting process (riveting). As shown in Figure 10 The riveting process is performed with the grommet 90 interposed between the outer side surface of the sealing plate 14 and the positive electrode terminal 30, and with the positive electrode insulating member 70 interposed between the inner side surface of the sealing plate 14 and the positive electrode first current collecting portion 51. Note that the grommet 90 can be made of the same material as the positive electrode insulating member 70. Specifically, the positive electrode terminal 30 before the riveting process is inserted in the through hole 90h of the grommet 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 collecting portion 51 in this order from above the sealing plate 14, and is caused to protrude downward of the sealing plate 14. Then, the portion of the positive electrode terminal 30 that protrudes downward of the sealing plate 14 is riveted in a manner to apply a compression force in the up-down direction Z. Thus, a rivet portion 30c is formed at the front end portion (lower end portion) of the positive electrode terminal 30. Figure 2

[0101] By the riveting process, the grommet 90, the sealing plate 14, the positive electrode insulating member 70, and the positive electrode first current collecting portion 51 are fixed to the sealing plate 14 integrally, and the terminal lead-out hole 18 is sealed. Note that the rivet portion 30c can be welded to the positive electrode first current collecting portion 51. Thus, the conduction reliability can be further improved.

[0102] The fixation of the negative electrode terminal 40, the negative electrode first current collecting portion 61, and the negative electrode insulating member 80 can be performed similarly to the positive electrode side described above. That is, the negative electrode terminal 40 before the riveting process is inserted in the through hole of the grommet, the terminal lead-out hole 19 of the sealing plate 14, the through hole of the negative electrode insulating member 80, and the through hole of the negative electrode first current collecting portion 61 in this order from above the sealing plate 14, and is caused to protrude downward of the sealing plate 14. Then, the portion of the negative electrode terminal 40 that protrudes downward of the sealing plate 14 is riveted in a manner to apply a compression force in the up-down direction Z. Thus, a rivet portion 40c is formed at the front end portion (lower end portion) of the negative electrode terminal 40. Figure 2

[0103] ​​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).

[0104] 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.

[0105] Next, as Figure 4 As shown, with the plurality of 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 plurality of negative electrode tabs 24t of the negative electrode tab assembly 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.

[0106] 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 13is 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 shape or a box shape, and an electrode body holder 29 is prepared. Next, the electrode body group 20 is housed in the electrode body holder 29. Then, the electrode body group 20 covered with the electrode body holder 29 is inserted into the exterior body 12. In the case where the electrode body group 20 is heavy, in the case where the weight is substantially 1 kg or more, for example, 1.5 kg or more, further, 2 to 3 kg, as shown in FIG. 6, the electrode body group 20 is inserted into the exterior body 12 in a manner that the long side wall 12b of the exterior body 12 crosses the direction of gravity (the exterior body 12 is arranged laterally). Figure 13

[0107] The bent portions 20r of the wound electrode bodies 20a, 20b, 20c that constitute the electrode body group 20 are pressed by the protruding portions 70b of the positive electrode insulating member 70 and / or the protruding portions 80b of the negative electrode insulating member 80, and are pressed into the interior of the exterior body 12. By pressing the electrode body group 20 with the protruding portions 70b and / or the protruding portions 80b, the load on the positive electrode tab group 23 and / or the negative electrode tab group 25 can be reduced.

[0108] The positive electrode tab group 23 and / or the negative electrode tab group 25 has a gap that allows movement in a direction that crosses the direction of protrusion (typically, the up-down direction Z). Therefore, after the electrode body group 20 is inserted into the exterior body 12, if the exterior body 12 is stood up in a manner that the sealing plate 14 is positioned above, the electrode body group 20 slightly moves downward due to gravity. Thus, as shown in FIG. 6, the protruding portions 70b of the positive electrode insulating member 70 and the wound electrode bodies 20a, 20b, 20c are arranged at separate positions. Also, the protruding portions 80b of the negative electrode insulating member 80 and the wound electrode bodies 20a, 20b, 20c are arranged at separate positions. Figure 3

[0109] In the sealing process, the sealing plate 14 is joined to the edge portion of the opening 12h of the exterior body 12, and the opening 12h is sealed. The joining of the sealing plate 14 can be performed by welding such as laser welding. After that, the electrolyte solution is injected from the injection hole 15, and the injection hole 15 is plugged with the sealing member 16, and thus the battery 100 is hermetically sealed.

[0110] ​​In the activation process, first, the long side wall 12b of the sealed battery 100 is gripped by a restraining mechanism and pressed. Next, the battery 100 in the pressed state is subjected to, for example, initial charging, aging treatment, and self-discharge inspection, in the same manner as in the past. In the initial charging, an external power source is connected between the positive electrode terminal 30 and the negative electrode terminal 40, and the battery 100 is charged to a prescribed voltage. In the aging treatment, for example, the battery 100 is housed in a thermostat tank set to a prescribed temperature condition (for example, 40 to 60°C) and left for a prescribed time (for example, about 10 to 15 hours). In the self-discharge inspection, for example, first, the battery 100 after the aging treatment is adjusted to a prescribed state of charge in a normal temperature region (for example, 15 to 25°C). Next, the battery 100 is left for a certain time to self-discharge, and the voltage drop is measured. Next, based on the measured voltage drop, it is checked whether or not an internal short circuit has occurred in the battery 100 (whether or not it is a good product).

[0111] As described above, the battery 100 can be manufactured.

[0112] The battery 100 can be used for various uses, for example, can be appropriately used as a power source (driving power source) for an electric motor mounted on a vehicle such as a passenger car or a truck. The kind of vehicle is not particularly limited, and for example, a plug-in hybrid vehicle (PHV), a hybrid vehicle (HV), an electric vehicle (EV), or the like can be cited. The battery 100 can be applied to the construction of a battery pack.

[0113] The above describes several embodiments of the present application, but the above-described embodiments are merely examples. The present application can also be implemented in various other ways. The present application can be implemented based on the content disclosed in the present specification and technical common sense in the field. In the technology recited in the claims, technologies obtained by various modifications and changes to the above-described example embodiments are included. For example, a part of the above-described embodiments can be replaced with other modified examples, and other modified examples can be added to the above-described embodiments. In addition, if the technical feature is not described as a necessary technical feature, it can be appropriately deleted.

[0114] For example, the battery 100 of the above-described embodiment has the electrode body group 20 having a plurality of wound electrode bodies 20a, 20b, 20c. The wound electrode bodies 20b, 20c are the same structure as the wound electrode body 20a. However, it is not limited thereto. The wound electrode bodies 20b, 20c can be different structures from the wound electrode body 20a. For example, the number of the plurality of wound fixing bands 28 attached to the wound electrode bodies 20a, 20b, 20c can be different from each other. In addition, in the wound electrode bodies 20a, 20b, 20c, the positions at which the plurality of wound fixing bands 28 are attached can be different from each other.

[0115] Figure 14Ais a main view schematically showing the first wound electrode body 120a. Figure 14B is a main view schematically showing the second wound electrode body 120b. The battery of the modified example has the first wound electrode body 120a and the second wound electrode body 120b. An odd number of the wound fixing bands 28 are attached to the outer surface of the first wound electrode body 120a. An even number of the wound fixing bands 28 are attached to the outer surface of the second wound electrode body 120b. In the first wound electrode body 120a and the second wound electrode body 120b, the number of the wound fixing bands 28 is different from each other.

[0116] In addition, in the first wound electrode body 120a and the second wound electrode body 120b, the positions of the wound fixing bands 28 are arranged with a shift in the long side direction Y. Thereby, it is possible to suppress the partial increase in the thickness of the electrode group (the first wound electrode body 120a and the second wound electrode body 120b). In addition, it is possible to make the wound electrode bodies 120a, 120b balance well in charge and discharge. In the long side direction Y, Figure 14A the total length of the plurality of wound fixing bands 28 of the first wound electrode body 120a and Figure 14B the total length of the plurality of wound fixing bands 28 of the second wound electrode body 120b can also be substantially the same as the length LI of the positive active material layer of the first wound electrode body 120a and the second wound electrode body 120b (manufacturing error can be allowed).

[0117] This application claims priority from Japanese Patent Application No. 2020-186228 filed November 9, 2020, the entire contents of which are incorporated herein by reference.

Claims

1. A battery, wherein the battery comprises: an exterior body having a bottom wall and an opening facing the bottom wall; a sealing plate sealing the opening of the exterior body; one or more wound electrode bodies each comprising a positive electrode having a positive active material layer and a negative electrode having a negative active material layer stacked with a strip-shaped separator and wound around a winding axis; and a plurality of wound fixing tapes adhered to an outer surface of the wound electrode body, the wound electrode body is housed in the exterior body with the winding axis along the bottom wall of the exterior body, the length of the positive active material layer in the winding axis direction of the wound electrode body is 15 cm or more, the plurality of wound fixing tapes are each rectangular having a long side and a short side, the plurality of wound fixing tapes are adhered to the outer surface of the wound electrode body at intervals along the winding axis direction with the long side of the rectangular oriented along the winding axis direction, the interval between adjacent wound fixing tapes is 105 mm or less, the wound electrode body has a pair of curved portions and a flat portion connecting the pair of curved portions, in the state of the wound electrode body, the dimension of each of the plurality of wound fixing tapes in a direction orthogonal to the winding axis direction is smaller than the dimension of the flat portion in the direction orthogonal to the winding axis direction, and in the winding axis direction, each of the plurality of wound fixing tapes is distanced from an end portion of the wound electrode body in the winding axis direction among the outer surface of the wound electrode body.

2. The battery according to claim 1, wherein the wound electrode body is plural, the plurality of wound fixing tapes are adhered to each of the plural wound electrode bodies.

3. The battery according to claim 1, wherein the battery comprises: a positive tab group including a plurality of positive tabs protruding from one end portion in the winding axis direction of the wound electrode body and electrically connected to the positive electrode; and a negative tab group including a plurality of negative tabs protruding from the other end portion in the winding axis direction of the wound electrode body and electrically connected to the negative electrode.

4. The battery according to claim 3, wherein in a direction perpendicular to the sealing plate, the positive tab group and the negative tab group are eccentrically arranged toward the sealing plate side.

5. The battery according to claim 3 or 4, wherein the plurality of wound fixing tapes are arranged on a straight line connecting the positive tab group and the negative tab group.

6. The battery according to any one of claims 1 to 4, wherein in the winding axis direction, the proportion of the total length of the plurality of wound fixing tapes to the length of the positive active material layer is 20% or more and 70% or less.

7. The battery according to any one of claims 1 to 4, wherein the interval between adjacent wound fixing tapes is 30 mm or more and 105 mm or less.

8. A battery, wherein the battery comprises: an outer case having a bottom wall and an opening facing the bottom wall; a seal plate sealing the opening of the outer case; one or more wound electrode bodies each of which is formed by stacking a strip-shaped positive electrode having a positive active material layer and a strip-shaped negative electrode having a negative active material layer with a strip-shaped separator interposed therebetween and winding the stack around a winding axis; a positive tab group including a plurality of positive tabs protruding in one end direction of the winding axis of the wound electrode body and electrically connected to the positive electrode; and a negative tab group including a plurality of negative tabs protruding in the other end direction of the winding axis of the wound electrode body and electrically connected to the negative electrode, the plurality of positive tabs are convex portions provided at intervals along the length direction of the strip-shaped positive electrode and are arranged at positions overlapping each other in the state of the wound electrode body, the plurality of negative tabs are convex portions provided at intervals along the length direction of the strip-shaped negative electrode and are arranged at positions overlapping each other in the state of the wound electrode body, the wound electrode body is housed in the outer case with the winding axis along the bottom wall of the outer case, in a direction perpendicular to the seal plate, the positive tab group and the negative tab group are arranged eccentrically toward the seal plate side, in the winding axis direction of the wound electrode body, the length of the positive active material layer is 15 cm or more, the plurality of wound fixing tapes are rectangular each having a long side and a short side, the plurality of wound fixing tapes are attached to the outer surface of the wound electrode body at intervals along the winding axis direction with the long side of the rectangle oriented in the winding axis direction, in the winding axis direction of the wound electrode body, the plurality of wound fixing tapes are arranged only on the central side compared to the positive tab group and the negative tab group, the wound electrode body has a pair of curved portions and a flat portion linking the pair of curved portions, in the state of the wound electrode body, the dimension of each of the plurality of wound fixing tapes in a direction orthogonal to the winding axis direction is smaller than the dimension of the flat portion in a direction orthogonal to the winding axis direction, and in the winding axis direction, each of the plurality of wound fixing tapes is distanced from the end portion of the wound electrode body in the winding axis direction among the outer surface of the wound electrode body.

9. The battery according to claim 8, wherein the wound electrode body is plural.

10. The battery according to claim 8 or 9, wherein the plurality of wound fixing tapes are arranged on a straight line linking the positive tab group and the negative tab group.

11. The battery according to claim 8 or 9, wherein in the winding axis direction, the proportion of the total length of the plurality of wound fixing tapes to the length of the positive active material layer is 20% or more and 70% or less.

12. The battery according to claim 8 or 9, wherein the interval between adjacent ones of the plurality of wound fixing tapes is 30 mm or more and 105 mm or less.

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