JP7459035B2 - battery - Google Patents

Description

The present invention relates to a battery.

Conventionally, a strip-shaped positive electrode having a positive electrode active material layer on a positive electrode core and a strip-shaped negative electrode having a negative electrode active material layer on a negative electrode core are laminated with a strip-shaped separator interposed therebetween. BACKGROUND ART A battery including a wound electrode body wound around the center is known (for example, Patent Document 1).

International Publication No. 2021/060010

An object of the present invention is to provide a battery in which an electrolytic solution easily permeates the entire wound electrode body and gas is difficult to accumulate inside the electrode body.

The battery disclosed herein includes a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and a pair of second side walls facing the bottom wall. a square exterior body having an opening, a sealing plate for sealing the opening, a strip-shaped positive electrode plate and a strip-shaped negative electrode plate housed inside the square exterior body, and wound with a strip-shaped separator interposed therebetween. A flattened wound electrode body is provided. The negative electrode plate has a main body having a negative electrode core and a negative electrode active material layer formed on the negative electrode core, and the main body has a first long end side in the winding axis direction. and a second long end side. A negative electrode tab in which the negative electrode core body is exposed without forming the negative electrode active material layer is provided on the first long end side. The wound electrode body has a winding axis arranged along the bottom wall of the square exterior body, and the height direction of the wound electrode body is perpendicular to the bottom wall. In some cases, a height T1 of the wound electrode body at a portion where the first long side is located is different from a height T2 of the wound electrode body at a portion where the second long side is located.

The wound electrode body of the battery has a height from the bottom wall that is asymmetrical in the direction of the winding axis. As a result, a region where the non-aqueous electrolyte is difficult to permeate tends to occur near one of the ends instead of at the center in the direction of the winding axis. Therefore, the gas accumulated in this area is also easily released from either end. In addition, when charging and discharging a battery, gas from the decomposition of the non-aqueous electrolyte tends to accumulate inside the wound electrode body. becomes more easily excreted. Therefore, gas is less likely to accumulate inside the wound electrode body, making it possible to provide a battery with higher safety.

In a preferred embodiment of the battery disclosed herein, the length of the main body of the negative plate in the direction of the winding axis is 20 cm or more. In a wound electrode body having such a relatively large main body of a negative plate, the gas described above tends to accumulate inside, so it is particularly effective to apply the technology disclosed herein.

In a preferred aspect of the battery disclosed herein, a height T1 of the wound electrode body at the portion where the first long end side is located is higher than the height T1 of the wound electrode body at the portion where the second long end side is located. It is characterized by being higher than the height T2 of the rotating electrode body. Further, in an embodiment in which T1 is higher than T2, the wound electrode body at the portion where the first long end side is located is relative to the height T2 of the wound electrode body at the portion where the second long end side is located. The ratio of body height T1 (T1/T2) is preferably 100.1% or more and 105% or less. With such a configuration, gas accumulated inside the wound electrode body can be more easily discharged.

The positive electrode plate has a positive electrode core and a positive electrode active material layer formed on the positive electrode core, and the positive electrode active material layer is provided at one end in the winding axis direction of the positive electrode plate. A positive electrode tab is provided in which the positive electrode core is exposed without being formed. A negative electrode tab group in which a plurality of negative electrode tabs are stacked is arranged at one end of the wound electrode body in the winding axis direction, and a negative electrode tab group in which the plurality of negative electrode tabs are stacked is arranged at the other end of the wound electrode body in the winding axis direction. A positive electrode tab group in which a plurality of the positive electrode tabs described above are stacked is arranged. The negative electrode tab group is bent while being joined to a negative electrode current collector that is a conductive member, and the positive electrode tab group is bent while being joined to a positive electrode current collector that is a conductive member. In another preferred embodiment, a plurality of the wound electrode bodies are arranged inside the exterior body. Thereby, the volume that contributes to charging and discharging relative to the internal capacity of the square exterior body can be increased, so that battery performance is improved.

In a preferred embodiment of the battery disclosed herein, the thickness W1 of the wound electrode body at the portion where the first long end side is located is different from the thickness W2 of the wound electrode body at the portion where the second long end side is located. This allows the effects of the technology disclosed herein to be more effectively exerted.

In a preferred embodiment of the battery disclosed herein, the sealing plate has an injection hole for injecting a nonaqueous electrolyte, the injection hole is sealed with a sealing member, and the injection hole is located on the opposite side of the center of the sealing plate from the side on which the negative electrode tab is located in the longitudinal direction of the sealing plate. This allows impregnation to proceed from the side on which the negative electrode tab is not located, and gas accumulated inside the electrode body is easily discharged toward the first long end side on which the negative electrode tab is located and which is higher from the bottom wall.

In a preferred embodiment of the battery disclosed herein, the wound electrode body is arranged such that the upper end side of the wound electrode body is inclined with respect to the bottom wall. Thereby, the gas accumulated inside the wound electrode body can be more easily discharged.

FIG. 1 is a perspective view schematically showing a battery according to an embodiment. FIG. 2 is a schematic vertical cross-sectional view taken along line II-II in FIG. 1. FIG. FIG. 2 is a schematic vertical cross-sectional view taken along line III-III in FIG. FIG. 2 is a schematic cross-sectional view taken along line IV-IV in FIG. FIG. 4 is a perspective view showing a schematic view of an electrode assembly attached to a sealing plate. FIG. 2 is a plan view schematically showing an electrode body according to an embodiment. FIG. 2 is a schematic diagram showing the configuration of a wound electrode body. 7 is a schematic longitudinal sectional view taken along line VIII-VIII in FIG. 6. FIG. FIG. 7 is a schematic vertical cross-sectional view taken along line IX-IX in FIG. 6.

Hereinafter, some preferred embodiments of the technology disclosed herein will be described with reference to the drawings. Further, matters other than those specifically mentioned in this specification that are necessary for carrying out the present invention (for example, the general structure and manufacturing process of a battery that do not characterize the present invention) are well known in the art. This can be understood as a matter of design by a person skilled in the art based on the prior art. The present invention can be implemented based on the content disclosed in this specification and the common general knowledge in the field.

Note that in this specification, the term "battery" refers to all electricity storage devices that can extract electrical energy, and is a concept that includes primary batteries and secondary batteries. In addition, in this specification, "secondary battery" is a term that refers to all electricity storage devices that can be repeatedly charged and discharged, and includes so-called storage batteries (chemical batteries) such as lithium-ion secondary batteries and nickel-metal hydride batteries, and This concept includes capacitors (physical batteries) such as double layer capacitors.

<Battery 100>
FIG. 1 is a perspective view of a battery 100. FIG. 2 is a schematic vertical cross-sectional view taken along line II-II in FIG. FIG. 3 is a schematic vertical cross-sectional view taken along line III--III in FIG. FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a perspective view schematically showing the electrode assembly group 20 attached to the sealing plate 14. As shown in FIG. FIG. 6 is a plan view schematically showing the wound electrode body 20a of the battery disclosed herein. In the following description, the symbols L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom, and the symbols X, Y, and Z in the drawings represent batteries. 100, the short side direction, the long side direction perpendicular to the short side direction, and the height direction are respectively represented. The long side direction is an example of the winding axis direction. However, these directions are merely for convenience of explanation, and do not limit the installation form of the battery 100 in any way.

As shown in FIG. 2, the battery 100 includes a battery case 10, an electrode assembly 20, a positive terminal 30, a negative terminal 40, a positive current collector 50, and a negative current collector 60. . As will be described in detail later, the electrode body group 20 includes wound electrode bodies 20a, 20b, and 20c (see FIG. 3). Although not shown, the battery 100 further includes an electrolyte here. Battery 100 is a lithium ion secondary battery here. The battery 100 is characterized by having a wound electrode body whose height from the bottom wall is asymmetrical in the direction of the winding axis, and the other configuration may be the same as the conventional one.

The battery case 10 is a housing that houses the electrode assembly 20. Here, the battery case 10 has a flat, bottomed rectangular parallelepiped (square) outer shape. The material of the battery case 10 may be the same as that used conventionally, and is not particularly limited. The battery case 10 is preferably made of a metal, and more preferably made of, for example, aluminum, an aluminum alloy, iron, an iron alloy, or the like. As shown in FIG. 2, the battery case 10 includes an exterior body 12 having an opening 12h, and a sealing plate (lid) 14 that closes the opening 12h.

As shown in FIG. 1, the exterior 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. We are prepared. The bottom wall 12a has a substantially rectangular shape. The bottom wall 12a faces the opening 12h. The area of the short side wall 12c is smaller than the area of the long side wall 12b. Long side wall 12b and short side wall 12c are examples of the first side wall and second side wall disclosed herein. The sealing plate 14 is attached to the exterior body 12 so as to close the opening 12h of the exterior body 12. The sealing plate 14 faces the bottom wall 12a of the exterior body 12. The sealing plate 14 has a substantially rectangular shape in plan view. The battery case 10 is integrated by joining (for example, welding) a sealing plate 14 to the periphery of the opening 12h of the exterior body 12. The battery case 10 is hermetically sealed (sealed). Further, as shown in FIG. 2, the sealing plate 14 is provided with a liquid injection hole 15 and a gas discharge valve 17. The liquid injection hole 15 is for pouring an electrolytic solution after the sealing plate 14 is assembled to the exterior body 12. The liquid injection hole 15 is sealed by a sealing member 16. The gas exhaust valve 17 is configured to break when the pressure inside the battery case 10 exceeds a predetermined value, and discharge the gas inside the battery case 10 to the outside.

As described above, in addition to the electrode assembly 20, a non-aqueous electrolyte (not shown) is also housed inside the battery case 10. The electrolyte may be the same as the conventional one and is not particularly limited. The electrolytic solution is, for example, a non-aqueous electrolytic solution containing a non-aqueous solvent and a supporting salt. The nonaqueous solvent includes carbonates such as ethylene carbonate, dimethyl carbonate, and ethylmethyl carbonate. The supporting salt is, for example, a fluorine-containing lithium salt such as LiPF ₆ .

In the sealing plate 14, as shown in FIG. 2, two terminal extraction holes 18 and 19 and terminal extraction holes 18 and 19 are formed at both ends of the sealing plate 14 in the long side direction Y, respectively. The terminal extraction holes 18 and 19 penetrate the sealing plate 14 in the height direction Z. The terminal extraction holes 18 and 19 each have an inner diameter large enough to allow the positive electrode terminal 30 and the negative electrode terminal 40 to be inserted therethrough before being attached to the sealing plate 14, respectively.

The positive electrode terminal 30 and the negative electrode terminal 40 are each fixed to the sealing plate 14. The positive electrode terminal 30 is arranged on one side of the sealing plate 14 in the long side direction Y (on the left side in FIGS. 1 and 2). The negative electrode terminal 40 is arranged on the other side of the sealing plate 14 in the long side direction Y (on the right side in FIGS. 1 and 2). As shown in FIG. 1, the positive electrode terminal 30 and the negative electrode terminal 40 are exposed on the outer surface of the sealing plate 14. As shown in FIG. 2, the positive electrode terminal 30 and the negative electrode terminal 40 extend from the inside of the sealing plate 14 to the outside by passing through the terminal extraction holes 18 and 19.

2 to 5, in the battery 100 according to this embodiment, a plurality of (three) wound electrode bodies 20a, 20b, and 20c are housed in the battery case 10. The detailed structure will be described later, but each of the wound electrode bodies 20a, 20b, and 20c is provided with a positive electrode tab group 23 and a negative electrode tab group 25. The above-mentioned positive electrode terminal 30 is connected to each of the positive electrode tab groups 23 of the plurality of wound electrode bodies 20a, 20b, and 20c via the positive electrode current collector 50. Specifically, the positive electrode current collector 50 is housed inside the battery case 10. As shown in FIGS. 2 and 5, the positive electrode current collector 50 includes a positive electrode first current collector 51, which is a plate-shaped conductive member extending in the long side direction Y along the inner side surface of the sealing plate 14, and a plurality of positive electrode second current collectors 52, which are plate-shaped conductive members extending along the height direction Z. The lower end 30c of the positive electrode terminal 30 is inserted into the battery case 10 through the terminal pull-out hole 18 of the sealing plate 14 and connected to the positive electrode first current collector 51 (see FIG. 2). On the other hand, as shown in FIG. 4, the battery 100 is provided with a number of positive electrode second current collectors 52 corresponding to the number of wound electrode bodies. Each positive electrode second current collector 52 is connected to each positive electrode tab group 23 of the multiple wound electrode bodies 20a, 20b, and 20c. As shown in FIG. 4 and FIG. 5, each positive electrode tab group 23 of the multiple wound electrode bodies 20a, 20b, and 20c is bent so that the positive electrode second current collector 52 and one side surface 20e of the wound electrode bodies 20a, 20b, and 20c face each other. As a result, the upper end of the positive electrode second current collector 52 and the positive electrode first current collector 51 are electrically connected.

On the other hand, the negative electrode terminal 40 is connected to the negative electrode tab group 25 of each of the plurality of wound electrode bodies 20a, 20b, and 20c via the negative electrode current collector 60. The connection structure on the negative electrode side is substantially the same as the connection structure on the positive electrode side described above. Specifically, the negative electrode current collector 60 includes a negative electrode first current collector 61 that is a plate-shaped conductive member that extends in the long side direction Y along the inner surface of the sealing plate 14, and a negative electrode first current collector 61 that is a plate-shaped conductive member that extends in the long side direction Y along the inner surface of the sealing plate 14. It includes a plurality of negative electrode second current collectors 62 that are elongated plate-shaped conductive members (see FIGS. 2 and 5). The lower end portion 40c of the negative electrode terminal 40 is inserted into the battery case 10 through the terminal extraction hole 19 and connected to the negative electrode first current collector 61 (see FIG. 2). On the other hand, each of the plurality of negative electrode second current collectors 62 is connected to the negative electrode tab group 25 of each of the plurality of wound electrode bodies 20a, 20b, and 20c (see FIGS. 4 and 5). Then, the negative electrode tab group 25 is bent so that the negative electrode second current collector 62 and the other side surface 20g of the wound electrode bodies 20a, 20b, and 20c face each other. As a result, the upper end of the second negative current collector 62 and the first negative current collector 61 are electrically connected.

The positive electrode terminal 30 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy, for example. The negative electrode terminal 40 is preferably made of metal, and more preferably made of copper or a copper alloy, for example. The negative electrode terminal 40 may be configured by joining two electrically conductive members and integrating them. For example, the portion connected to the negative electrode current collector 60 may be made of copper or a copper alloy, and the portion exposed on the outer surface of the sealing plate 14 may be made of aluminum or an aluminum alloy. Further, metals with excellent conductivity (aluminum, aluminum alloy, copper, copper alloy, etc.) can also be suitably used for the electrode current collectors (the positive electrode current collector 50 and the negative electrode current collector 60).

As shown in FIG. 1, a plate-shaped positive external conductive member 32 and a negative external conductive member 42 are attached to the outer surface of the sealing plate 14. The positive external conductive member 32 is electrically connected to the positive terminal 30. The negative external conductive member 42 is electrically connected to the negative terminal 40. The positive external conductive member 32 and the negative external conductive member 42 are members to which a bus bar is attached when electrically connecting the plurality of batteries 100 to each other. The positive external conductive member 32 and the negative external conductive member 42 are preferably made of metal, and more preferably made of, for example, aluminum or an aluminum alloy. However, the positive external conductive member 32 and the negative external conductive member 42 are not essential and may be omitted in other embodiments.

In addition, in this battery 100, various insulating members are attached to prevent electrical conduction between the electrode assembly 20 and the battery case 10. Specifically, the positive electrode external conductive member 32 and the negative electrode external conductive member 42 are insulated from the sealing plate 14 by an external insulating member 92. In addition, the positive electrode terminal 30 is insulated from the sealing plate 14 by a positive electrode insulating member 70 and a gasket 90. The negative electrode terminal 40 is insulated from the sealing plate 14 by a negative electrode insulating member 80 and a gasket 90.

As shown in FIG. 2, a positive electrode insulating member 70 is disposed between the positive electrode first current collector 51 and the inner surface of the sealing plate 14. The positive electrode insulating member 70 is a member that insulates the sealing plate 14 and the positive electrode first current collector 51. The positive electrode insulating member 70 is made of a resin material that has resistance to the electrolytic solution used, has electrical insulation properties, and is elastically deformable, such as polyolefin resin such as polypropylene (PP), tetrafluorocarbon It is preferably made of a fluorinated resin such as ethylene-perfluoroalkyl vinyl ether resin (PFA), polyphenylene sulfide (PPS), or the like.

The positive electrode insulating member 70 has a plate-shaped base portion 70a interposed between the positive electrode first current collecting portion 51 and the inner surface of the sealing plate 14. This can prevent the positive electrode first current collecting portion 51 from being electrically connected to the sealing plate 14. Furthermore, the positive electrode insulating member 70 has a protrusion portion 70b that protrudes from the inner surface of the sealing plate 14 toward the wound electrode bodies 20a, 20b, and 20c that constitute the electrode body group 20 (see FIG. 3). This can restrict the movement of the wound electrode bodies 20a, 20b, and 20c in the height direction Z, and can prevent the wound electrode bodies 20a, 20b, and 20c from directly contacting the sealing plate 14. Here, the number of protrusion portions 70b is the same as the number of wound electrode bodies 20a, 20b, and 20c that constitute the electrode body group 20. However, the number of protrusion portions 70b may be different from the number of electrodes that constitute the electrode body group 20, and may be, for example, one.

As shown in FIG. 2, the negative electrode insulating member 80 is arranged symmetrically with the positive electrode insulating member 70 with respect to the center CL of the electrode body group 20 in the long side direction Y. The configuration of the negative electrode insulating member 80 may be the same as that of the positive electrode insulating member 70. Like the positive electrode insulating member 70, the negative electrode insulating member 80 includes a base portion 80a disposed between the sealing plate 14 and the negative electrode first current collector 61, and a plurality of protrusions 80b.

The electrode body group 20 here includes three wound electrode bodies 20a, 20b, and 20c. However, the number of wound electrode bodies disposed inside one exterior body 12 is not particularly limited, and may be two or more (plurality) or one. The electrode body group 20 is placed inside the exterior body 12 while being covered by an electrode body holder 29 (see FIG. 3) made of a resin sheet.

The wound electrode body 20a is arranged inside the exterior body 12 with the winding axis WL along the bottom wall 12a (that is, the winding axis WL is parallel to the long side direction Y). In other words, the wound electrode body 20a is arranged inside the exterior body 12 with the winding axis WL parallel to the bottom wall 12a and perpendicular to the short side wall 12c. The end surface of the wound electrode body 20a (in other words, the laminated surface where the positive electrode plate 22 and the negative electrode plate 24 are laminated, the end surface in the long side direction Y in FIG. 7) faces the short side wall 12c. That is, the "winding axis direction" in the following description is substantially the same direction as the long side direction Y in the drawings.

Figure 7 is a schematic diagram showing the configuration of the wound electrode body 20a. The wound electrode body 20a has a positive electrode plate 22, a negative electrode plate 24, and a separator 26. In this case, the wound electrode body 20a is configured by stacking a strip-shaped positive electrode plate 22 and a strip-shaped negative electrode plate 24 with a strip-shaped separator 26 interposed therebetween, and winding the strip-shaped positive electrode plate 22 and the strip-shaped negative electrode plate 24 around the winding axis WL. The wound electrode body 20a has a flat shape.

As shown in FIG. 7, the negative electrode plate 24 includes a main body 24A having a negative electrode core 24c and a negative electrode active material layer 24a fixed on at least one surface of the negative electrode core 24c, and a negative electrode active material layer 24a. and a negative electrode tab 24t in which the negative electrode core body 24c is exposed without being formed. The main body portion 24A has a first long side 24e and a second long side 24f in the winding axis direction (long side direction Y), and the first long side 24e has a negative electrode. A tab 24t is provided.
In one preferred embodiment, the length of the main body portion 24A in the direction of the winding axis is 20 cm or more. For example, the length of the main body portion 24A in the winding axis direction may be 25 cm or more, or 30 cm or more. In a battery having such a relatively large main body, gas tends to accumulate inside the wound electrode body 20a, so that the effects of the technology disclosed herein are even more effective.

The negative electrode core body 24c is strip-shaped. The negative electrode core 24c is made of a conductive metal such as copper, copper alloy, nickel, stainless steel, or the like. The negative electrode core body 24c is a metal foil, specifically a copper foil here. A plurality of negative electrode tabs 24t are provided at one end of the negative electrode core body 24c in the long side direction Y (the right end in FIG. 7). The plurality of negative electrode tabs 24t protrude toward one side in the long side direction Y (the right side in FIG. 7). The plurality of negative electrode tabs 24t protrude beyond the separator 26 in the long side direction Y. The plurality of negative electrode tabs 24t are provided at intervals (intermittently) along the longitudinal direction of the negative electrode plate 24. The negative electrode tab 24t is a part of the negative electrode core body 24c here, and is made of metal foil (copper foil). The plurality of negative electrode tabs 24t each have a trapezoidal shape here. Here, the negative electrode tab 24t is a portion (core exposed portion) of the negative electrode core 24c where the negative electrode active material layer 24a is not formed. However, the negative electrode tab 24t may be a separate member from the negative electrode core body 24c. As shown in FIG. 7, the negative electrode tab 24t is provided at one end in the winding axis direction (the right end in FIG. 7).

As shown in FIG. 7, the negative electrode active material layer 24a is provided in a strip shape along the longitudinal direction of the strip-shaped negative electrode core body 24c. The negative electrode active material layer 24a includes a negative electrode active material (for example, a carbon material such as graphite) that can reversibly occlude and release charge carriers. When the entire solid content of the negative electrode active material layer 24a is 100% by mass, the negative electrode active material may account for approximately 80% by mass or more, typically 90% by mass or more, for example, 95% by mass or more. The negative electrode active material layer 24a may contain arbitrary components other than the negative electrode active material, such as a binder, a dispersant, various additive components, and the like. As the binder, for example, rubber such as styrene butadiene rubber (SBR) can be used. As a dispersant, for example, cellulose such as carboxymethyl cellulose (CMC) can be used.

As shown in FIG. 7, the positive electrode plate 22 has a main body having a positive electrode core 22c, a positive electrode active material layer 22a and a positive electrode protective layer 22p fixed to at least one surface of the positive electrode core 22c, and a plurality of positive electrode tabs 22t on which the positive electrode core 22c is exposed without the positive electrode active material layer 22a formed. However, the positive electrode protective layer 22p is not essential and may be omitted in other embodiments.

The positive electrode core 22c is strip-shaped. The positive electrode core 22c is made of a conductive metal such as aluminum, aluminum alloy, nickel, stainless steel, or the like. The positive electrode core body 22c is a metal foil, specifically an aluminum foil here. The plurality of positive electrode tabs 22t protrude toward one side (left side in FIG. 7) in the long side direction Y. The plurality of positive electrode tabs 22t protrude beyond the separator 26 in the long side direction Y. The plurality of positive electrode tabs 22t are provided at intervals (intermittently) along the longitudinal direction of the positive electrode plate 22. The positive electrode tab 22t is a part of the positive electrode core body 22c here, and is made of metal foil (aluminum foil). The positive electrode tabs 22t each have a trapezoidal shape here. The positive electrode tab 22t is a portion (core exposed portion) of the positive electrode core 22c where the positive electrode active material layer 22a and the positive electrode protective layer 22p are not formed. However, the positive electrode tab 22t may be a separate member from the positive electrode core 22c. Further, the positive electrode tab 22t is provided at the other end in the winding axis direction (the left end in FIG. 7).

As shown in FIG. 7, the positive electrode active material layer 22a is provided in a strip shape along the longitudinal direction Y of the strip-shaped positive electrode core body 22c. The positive electrode active material layer 22a includes a positive electrode active material (for example, a lithium transition metal composite oxide such as a lithium nickel cobalt manganese composite oxide) that can reversibly insert and release charge carriers. When the entire solid content of the positive electrode active material layer 22a is 100% by mass, the positive electrode active material may occupy approximately 80% by mass or more, typically 90% by mass or more, for example, 95% by mass or more. The positive electrode active material layer 22a may contain arbitrary components other than the positive electrode active material, such as a conductive material, a binder, and various additive components. As the conductive material, for example, a carbon material such as acetylene black (AB) can be used. As the binder, for example, polyvinylidene fluoride (PVdF) can be used.

As shown in FIG. 7, the positive electrode protective layer 22p is provided at the boundary between the positive electrode core 22c and the positive electrode active material layer 22a in the long side direction Y. The positive electrode protective layer 22p is provided here at one end in the long side direction Y (the left end in FIG. 7) of the positive electrode core 22c. However, the positive electrode protective layer 22p may 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 an inorganic filler (eg, alumina). When the entire solid content of the positive electrode protective layer 22p is 100% by mass, the inorganic filler may account for approximately 50% by mass or more, typically 70% by mass or more, for example 80% by mass or more. The positive electrode protective layer 22p may contain arbitrary components other than the inorganic filler, such as a conductive material, a binder, and various additive components. The conductive material and binder may be the same as those exemplified as being included in the positive electrode active material layer 22a.

The separator 26 is a member that insulates the positive electrode active material layer 22a of the positive electrode plate 22 and the negative electrode active material layer 24a of the negative electrode plate 24. Separator 26 constitutes the outer surface of wound electrode body 20a. As the separator 26, a porous sheet made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is suitable, for example. The separator 26 here includes a base material portion made of a porous sheet made of resin, and a heat resistance layer (HRL) formed on at least one surface of the base material portion. The heat-resistant layer is typically a layer containing an inorganic filler and a binder. As the inorganic filler, for example, alumina, boehmite, aluminum hydroxide, titania, etc. can be used. As the binder, for example, polyvinylidene fluoride (PVdF) or the like may be used.

Next, a specific structure of the wound electrode body 20a including the above-described positive electrode plate 22, negative electrode plate 24, and separator 26 will be described. 8 is a schematic cross-sectional view taken along line VIII-VIII in FIG. 6, and FIG. 9 is a schematic cross-sectional view taken along line IX-IX in FIG. FIG. 8 schematically shows a cross-sectional view of the end on the first long side 24e side (hereinafter also referred to as "the end on the negative electrode tab 24t side") in the direction of the winding axis of the wound electrode body 20a. ing. FIG. 9 schematically shows a cross-sectional view of the end on the second long side 24f side (hereinafter also referred to as "the end on the positive electrode tab 22t side") in the direction of the winding axis of the wound electrode body 20a. It shows. In addition, although the wound electrode body 20a will be explained in detail below as an example, the same structure can be applied to the wound electrode bodies 20b and 20c.

The wound electrode body 20a is produced by stacking the positive electrode plate 22 and the negative electrode plate 24 with two separators 26a and 26b in between and winding the laminated layers. Specifically, first, a laminate is produced in which the first separator 26a, the negative electrode plate 24, the second separator 26b, and the positive electrode plate 22 are laminated in this order (see FIG. 7). At this time, only the positive electrode tab 22t of the positive electrode plate 22 protrudes from one (left side in FIG. 7) side edge in the long side direction Y, and the negative electrode tab 24t of the negative electrode plate 24 protrudes from the other (right side in FIG. 7) side edge. The stacking position of each sheet member in the long side direction Y is adjusted so that only the sheet members protrude. Then, the produced laminate is wound to produce a cylindrical body. The number of turns at this time is preferably adjusted as appropriate in consideration of the intended performance and manufacturing efficiency of the wound electrode body 20a. As an example, the number of turns of the wound electrode body 20a is preferably 10 to 60 times, more preferably 30 to 40 times. Then, by pressing this cylindrical body, a flat-shaped wound electrode body 20a is produced. Then, the first separator 26a is arranged on the outermost surface of the wound electrode body 20a after production. The shape of the wound electrode body 20a is maintained by pasting a winding tape (not shown) to the terminal end of the first separator 26a.

At one end of the wound electrode body 20a in the direction of the winding axis, a plurality of negative electrode tabs 24t are stacked to form a negative electrode tab group 25 (see FIG. 4). The plurality of negative electrode tabs 24t are bent and curved so that their outer ends are aligned. The negative electrode tab group 25 is electrically connected to the negative electrode terminal 40 via the negative electrode current collector 60 . Further, a plurality of positive electrode tabs 22t are stacked on the other end of the wound electrode body 20a in the direction of the winding axis after winding, thereby forming a positive electrode tab group 23 (see FIG. 4). The plurality of positive electrode tabs 22t are bent and curved so that their outer ends are aligned. The positive electrode tab group 23 is electrically connected to the positive electrode terminal 30 via the positive electrode current collector 50 . On the other hand, in the central portion of the wound electrode body 20a in the direction of the winding axis, a charge/discharge region is formed in which the positive electrode active material layer 22a and the negative electrode active material layer 24a face each other, and where charge/discharge reactions mainly occur.
It is preferable that the plurality of positive electrode tabs 22t be bent and electrically connected to the positive electrode terminal 30. Moreover, it is preferable that the plurality of negative electrode tabs 24t be bent and electrically connected to the negative electrode terminal 40. Thereby, the accommodation capacity in the battery case 10 can be improved and the battery 100 can be made smaller. Furthermore, since the volume of the charging/discharging region can be increased relative to the internal capacity of the battery case 10, battery performance is improved.

As described above, the wound electrode body 20a of the battery 100 disclosed herein is formed into a flat shape by press molding. As shown in FIG. 3, the flat-shaped wound electrode body 20a has a pair of curved portions 20r with curved outer surfaces and a flat portion 20f with a flat surface that connects the pair of curved portions 20r. The flat portion 20f of the wound electrode body 20a faces the long side wall 12b of the exterior body 12. The pair of curved portions 20r each face the bottom wall 12a and the sealing plate 14. One curved portion 20r (upper side of FIG. 3) here faces the sealing plate 14 indirectly via the positive electrode first current collecting portion 51, the negative electrode first current collecting portion 61, the positive electrode insulating member 70, and the negative electrode insulating member 80, etc. The other curved portion 20r (lower side of FIG. 3) here faces the bottom wall 12a indirectly via the electrode body holder 29.

As shown in FIG. 8, the vertices of the curved portions 20r1 and 20r2 on the first long side 24e side of the wound electrode body 20a (that is, the vertices of the upper and lower ends of the outermost curved portion of the wound electrode body 20a) Let them be a vertex P1 and a vertex P2. A straight line connecting the apex P1 of the curved portion 20r1 and the vertex P2 of the curved portion 20r2 in a cross-sectional view is defined as a straight line L1. Further, as shown in FIG. 9, in the wound electrode body 20a, the vertices of the curved portions 20r3 and 20r4 on the second long end side 24f side (that is, the top and bottom ends of the curved portion on the outermost periphery of the wound electrode body 20a) vertices) as a vertex P3 and a vertex P4. A straight line connecting the apex P3 of the curved portion 20r3 and the vertex P4 of the curved portion 20r4 in a cross-sectional view is defined as a straight line L2.
Note that the straight line L1 and the straight line L2 are straight lines that are perpendicular to the winding axis WL of the wound electrode body 20a and perpendicular to the bottom wall 12a.

The wound electrode body 20a of the battery 100 disclosed herein is such that the first long side 24e of the wound electrode body 20a is located when the height direction Z is the direction perpendicular to the bottom wall 12a. It is characterized in that the height T1 of the portion is different from the height T2 of the portion where the second long end side 24f is located. Here, "the portion of the wound electrode body 20a where the first long end side 24e is located" is the portion of the wound electrode body 20a that is closest to the sealing plate 14. For example, it may be the vertex P1 of the curved portion 20r1 on the side of the first long end side 24e described above. Furthermore, "the portion of the wound electrode body 20a where the second long end side 24f is located" is the portion of the wound electrode body 20a that is closest to the sealing plate 14. For example, it may be the apex P3 of the curved portion 20r3 on the second long side 24f side described above.

In the wound electrode body 20a of the battery 100 disclosed herein, the height T1 of the portion where the first long end side 24e is located and the height T2 of the portion where the second long end side 24f is located are different, so that the gas generated during injection of the non-aqueous electrolyte or during charging and discharging of the battery 100 is easily discharged from the wound electrode body 20a. This provides a battery with higher safety. During injection of the non-aqueous electrolyte, it is difficult to uniformly permeate the entire wound electrode body with the non-aqueous electrolyte, and uneven permeation is particularly likely to occur in the early stages of injection. This region where the non-aqueous electrolyte is difficult to permeate is a region where gas is likely to accumulate because the gas does not escape due to injection. When the height from the bottom wall in the winding axis direction is symmetrical as in the conventionally known wound electrode body, there is a tendency for a region where the non-aqueous electrolyte does not permeate, especially in the approximate center of the electrode body, to occur, and the gas accumulated in that region is also difficult to escape. On the other hand, when the height from the bottom wall in the winding axis direction is asymmetric as in the case of the wound electrode body 20a disclosed herein, there is a tendency for an area where the nonaqueous electrolyte does not penetrate to occur near one of the ends. Therefore, the gas that has accumulated in such an area also tends to escape from one of the ends. In addition, when the battery is charged and discharged, the gas generated by the decomposition of the nonaqueous electrolyte tends to accumulate inside the wound electrode body. As shown in FIG. 6, the height of the wound electrode body 20a from the bottom wall 12a of the wound electrode body 20a gradually increases from the positive electrode tab 22t side to the negative electrode tab 24t side. This allows the gas that remains inside the wound electrode body 20a to be suitably released from the end on the negative electrode tab 24t side. Therefore, the battery 100 disclosed herein is a battery in which gas is less likely to accumulate inside the wound electrode body 20a, making it safer.

In one preferred embodiment, the height T1 of the portion of the wound electrode body 20a where the first long side 24e is located is higher than the height T2 of the portion where the second long side 24f is located. In other words, the height of the end on the negative electrode tab 24t side (right side in FIG. 6) from the bottom wall 12a is higher than the height from the bottom wall 12a of the end on the positive electrode tab 22t side (left side in FIG. 6). It is configured as follows. This configuration is preferable because even if gas accumulates inside the wound electrode body 20a, the gas is discharged from the end on the negative electrode tab 24t side.

By the way, the wound electrode bodies 20a, 20b, and 20c are housed in, for example, a bag-shaped electrode body holder 29 as shown in FIG. 3 in a state that they are integrated with the sealing plate 14 as shown in FIG. It is accommodated in 12 internal spaces. At this time, each of the wound electrode bodies 20a, 20b, and 20c of the electrode body group 20 is housed so that the winding axis WL is substantially parallel to the bottom wall 12a of the exterior body 12. Further, it is preferable that the upper end side of the wound electrode body 20a is inclined with respect to the bottom wall 12a. Further, although not particularly limited, the lower curved portions 20r2 and 20r4 of the wound electrode body 20a are accommodated so as to be in contact with the bottom wall 12a of the exterior body 12 via the electrode body holder 29. This is preferable because the electrode assembly 20 can be stably installed inside the exterior body 12. In this way, when each wound electrode body is housed so as to be substantially parallel to the bottom wall 12a, the height from the bottom wall 12a is increased from the end on the positive electrode tab 22t side to the end on the negative electrode tab 24t side. In order to arrange the winding electrode body 20a so as to be inclined so as to gradually increase the height, the height of the wound electrode body 20a itself from the bottom wall 12a needs to gradually increase. The wound electrode body 20a having such a shape can be manufactured, for example, by adjusting the tension during winding and the diameter of the winding axis WL. Specifically, the tension of the winding device on the positive electrode tab 22t side may be adjusted to be higher than the tension of the winding device on the negative electrode tab 24t side. Thereby, the negative electrode tab 24t side is wound more loosely than the positive electrode tab 22t side, so that it is possible to manufacture the wound electrode body 20a in which T1 is higher than T2 in height from the bottom wall 12a. Further, the length of the outer circumference of the winding shaft WL may be adjusted so that it is longer on the negative electrode tab 24t side than on the positive electrode tab 22t side. Thereby, the shape of the winding axis WL is reflected on the wound electrode body 20a, and it is possible to manufacture the wound electrode body 20a in which T1 is higher than T2 in height from the bottom wall 12a.

In a preferred aspect, the ratio (T1/T2) of the height T1 of the portion where the first long side 24e is located to the height T2 of the portion where the second long side 24f is located improves gas discharge. From the viewpoint of achieving this, it is preferable that it is at least 100.1%. On the other hand, considering the accommodation efficiency within the battery case 10, the ratio of T1 to T2 (T1/T2) is preferably 105% or less. The ratio of T1 to T2 (T1/T2) is, for example, preferably 100.1% or more and 105% or less, more preferably 100.1% or more and 103% or less, and 100.1% or more and 101%. It is more preferably at most 100.1% or more and at most 100.3%. This makes it difficult for gas to accumulate inside the wound electrode body 20a, and a sufficient charge/discharge area is ensured, making it possible to provide a battery with improved battery performance.
Note that when a wound electrode body is manufactured using a general method for manufacturing a wound electrode body, the height of the wound electrode body from the bottom wall 12a becomes asymmetrical in the direction of the winding axis as described above. This is not the case; for example, the ratio of T1 to T2 (T1/T2) is only a value below the third decimal place. Therefore, by adjusting the tension of the winding device and the shape of the winding shaft as described above, it is possible to realize a wound electrode body in which the ratio of T1 to T2 (T1/T2) is adjusted. I can do it.

As described above, in the battery 100 disclosed herein, in the wound electrode body 20a, the height from the bottom wall 12a of the end on the negative electrode tab 24t side is greater than the height from the bottom wall 12a of the end on the positive electrode tab 22t side. It is higher than the height from From the viewpoint of performing liquid injection more appropriately, the liquid injection hole 15 is preferably provided at a lower height from the bottom wall 12a, that is, on the positive electrode tab 22t side. As shown in FIG. 1, it is preferable that it be provided closer to the positive electrode terminal 30 than the center line CL of the battery case 10.

As shown in FIG. 8, the negative electrode plate 24 includes a first flat part 27a extending from the negative electrode starting end 24s along the flat part 20f, and a first flat part 27a that is folded back from the end of the first flat part 27a along the curved part 20r2. a first folded portion 28a, a second flat portion 27b extending from the end of the first folded portion 28a along the flat portion 20f, and a second folded portion folded back from the end of the second flat portion 27b along the curved portion 20r1. 28b. Here, in the second folded portion 28b, when a point through which the straight line L1 passes is defined as an apex P5, the length of the apex P5 and the apex P1 in the height direction Z is defined as R. Further, as shown in FIG. 9, in a cross-sectional view on the second long end side 24f side of the wound electrode body 20a, the first flat portion 27a, the second flat portion 27b, the first folded portion It has a portion 28a and a second folded portion 28b. Here, in the second folded portion 28b, when a point through which the straight line L2 passes is defined as an apex P6, the length of the apex P6 and the apex P2 in the height direction Z is defined as r. Further, as shown in FIG. 8, the thickness (length in the short side direction X) of the wound electrode body 20a on the first long side 24e side is set to W1, and as shown in FIG. The thickness (length in the short side direction X) of the wound electrode body 20a is defined as W2. Note that W1 and W2 may be the maximum thickness (maximum length in the short side direction X) of the wound electrode body 20a.

In the wound electrode body 20a of the battery 100 disclosed herein, the ratio (R/r) of the length R of the apex P1 and the apex P5 to the length r of the apex P3 and the apex P6 is 1<R/r. It is preferable that <1.1, it is more preferable that 1<R/r<1.05, and it is especially preferable that 1<R/r<1.03. By adjusting to this range, gas that may exist inside the wound electrode body 20a is more easily discharged from the end on the negative electrode tab 24t side.

Further, in a preferred embodiment of the wound electrode body 20a of the battery 100 disclosed herein, the thickness W1 of the wound electrode body 20a on the first long side 24e side and the thickness of the wound electrode body 20a on the second long side 24f side are The thickness W2 of the electrode body 20a is different. More preferably, the thickness W1 of the wound electrode body 20a on the first long side 24e side is configured to be thicker than the thickness W2 of the wound electrode body 20a on the second long side 24f side. good. A method of creating the wound electrode body 20a having different thicknesses on the first long side 24e side and the second long side 24f side is to adjust the tension during winding as described above. can be mentioned. When the tension is adjusted when winding the wound electrode body 20a, the first long end side 24e side is wound more loosely than the second long end side 24f side, and the first long end side The thickness on the 24e side is slightly thicker. In other words, the first long end side 24e is wound so that the gap generated each round is larger than that on the second long end side 24f. The gap for each round may be configured such that, for example, the gap is small at the winding start side and becomes larger as it approaches the winding end side. More preferably, the gap between each round is uniform.

In another preferred aspect, the ratio (r/W2) of the thickness W2 of the wound electrode body 20a to the length r of the apex P3 and the apex P6 on the second long end side 24f side The ratio (R/W1) of the thickness W1 of the wound electrode body 20a to the length R of the apex P1 and the apex P5 on the side 24e side is larger. Thereby, gas that may exist inside the wound electrode body 20a is easily discharged from the end on the first long side 24e side.

As shown in FIGS. 4 and 5, the negative electrode second current collector 62 has a negative electrode tab joint 62a attached to the negative electrode tab group 25 and electrically connected to the plurality of negative electrode tabs 24t. Similarly, the positive electrode second current collector 52 has a positive electrode tab joint 52a attached to the positive electrode tab group 23 and electrically connected to the plurality of positive electrode tabs 22t. The negative electrode tab joint portion 62a and the positive electrode tab joint portion 52a extend along the height direction Z. The negative electrode tab joint portion 62a and the positive electrode tab joint portion 52a are arranged substantially perpendicular to the winding axis WL of the wound electrode bodies 20a, 20b, and 20c. The surfaces of the negative tab joint 62a and the positive tab joint 52a that are connected to the plurality of negative tabs 24t or the positive tabs 22t are arranged substantially parallel to the short side wall 12c of the exterior body 12. As shown in FIG. 4, a joint J1 with the negative electrode tab group 25 is formed in the negative electrode tab joint 62a. A joint J2 with the positive electrode tab group 23 is formed in the positive electrode tab joint 52a. The joint is, for example, a welded joint formed by welding such as ultrasonic welding, resistance welding, laser welding, etc., with a plurality of negative electrode tabs 24t or positive electrode tabs 22t stacked one on top of the other. The joint portion J1 is arranged so that the plurality of negative electrode tabs 24t are brought to one side (the right side in FIG. 4) of the wound electrode bodies 20a, 20b, and 20c in the short side direction X. The joint J2 is arranged so that the plurality of positive electrode tabs 22t are brought to one side (the left side in FIG. 4) of the wound electrode bodies 20a, 20b, and 20c in the short side direction X. Thereby, the plurality of negative electrode tabs 24t and positive electrode tabs 22t can be more suitably bent to stably form the curved negative electrode tab group 25 and positive electrode tab group 23 as shown in FIG.

As shown in FIG. 2, the length in the height direction Z from the joint J1 between the negative electrode tab joint 62a and the negative electrode tab group 25 to the inner surface side of the sealing plate 14 is L1, and the length in the height direction Z from the joint J2 between the positive electrode tab joint 52a and the positive electrode tab group 23 to the inner surface side of the sealing plate 14 is L2. It is preferable that the length L1 from the joint J1 to the inner surface side of the sealing plate 14 is longer in the height direction Z than the length L2 from the joint J2 to the inner surface side of the sealing plate 14. The ratio of L1 to L2 (L1/L2) is preferably 95% or more and 99.8% or less, and more preferably 99% or more and 99.7% or less. When the negative electrode tab joint 62a and the negative electrode tab group 25, and the positive electrode tab joint 52a and the positive electrode tab group 23 are welded to each other, it is preferable that the lengths of L1 and L2 in the height direction Z are equal.

As described above, the electrode body group 20 is housed in, for example, a bag-shaped electrode body holder 29 as shown in FIG. 3 in a state where it is integrated with the sealing plate 14 as shown in FIG. It is housed in the internal space. At this time, the length G1 in the height direction Z from the portion of the wound electrode body 20a where the first long end side 24e is located to the inner surface of the sealing plate 14 (see FIG. 2), and The length G2 (see FIG. 2) in the height direction Z from the part where the second long end side 24f is located to the inner surface of the sealing plate 14 is accommodated so that G1 is shorter as shown in FIG. be done. This facilitates the discharge of gas accumulated inside the wound electrode body 20a. In addition, in the state before being housed inside the exterior body 12 (that is, the state in which the electrode assembly group 20 and the sealing plate 14 are integrated), the lengths of G1 and G2 in the height direction Z are made to be equal. It may be integrated into. Before being housed inside the exterior body 12, the ratio of G1 to G2 (G1/G2) is preferably smaller than the ratio of L1 to L2 (L1/L2), although this is not particularly limited.

Although the battery 100 can be used for various purposes, it can be suitably used, for example, as a power source (driving power source) for a motor mounted on a vehicle such as a passenger car or a truck. Although the type of vehicle is not particularly limited, examples thereof include a plug-in hybrid vehicle (PHEV), a hybrid vehicle (HEV), an electric vehicle (BEV), and the like. The battery 100 can be suitably used for constructing an assembled battery.

Although several embodiments of the present invention have been described above, the above embodiments are merely examples. The present invention can be implemented in various other forms. The present invention can be implemented based on the contents disclosed in this specification and the technical common sense in the relevant field. The technology described in the claims includes various modifications and changes to the above-exemplified embodiments. For example, it is possible to replace part of the above-mentioned embodiments with other modified forms, and it is also possible to add other modified forms to the above-mentioned embodiments. Furthermore, if a technical feature is not described as essential, it can also be deleted as appropriate.

10 Battery case 12 Exterior body 14 Sealing plate (lid body)
15 Liquid injection hole 16 Sealing member 20 Electrode body group 20a Wound electrode body 20b Wound electrode body 20c Wound electrode body 20f Flat portion 20r Curved portion 22 Positive electrode plate 22a Positive electrode active material layer 22c Positive electrode core 22p Positive electrode protective layer 22t Positive electrode tab 23 Positive electrode tab group 24 Negative electrode plate 24a Negative electrode active material layer 24A Main body 24c Negative electrode core 24e First long edge 24f Second long edge 24t Negative electrode tab 25 Negative electrode tab group 26 Separator 100 Battery

Claims (12)

A square exterior body having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall. and,
a sealing plate that seals the opening;
a flat wound electrode body housed inside the square exterior body, in which a band-shaped positive electrode plate and a band-shaped negative electrode plate are wound with a band-shaped separator interposed therebetween;
A battery comprising:
The negative electrode plate has a main body having a negative electrode core and a negative electrode active material layer formed on the negative electrode core,
The main body portion has a first long end side and a second long end side in the winding axis direction,
A negative electrode tab in which the negative electrode core is exposed without forming the negative electrode active material layer is provided on the first long end side,
The wound electrode body is arranged with a winding axis aligned with the bottom wall of the square exterior body,
In the wound electrode body, when the direction perpendicular to the bottom wall is the height direction,
A height T1 of the wound electrode body in a portion where the first long end side is located is different from a height T2 of the wound electrode body in a portion where the second long end side is located,
When the height T1 is larger than the T2, the size of the gap that occurs every round of the wound electrode body in the portion where the first long end is located is the same as the gap where the second long end is located. larger than the size of the gap that occurs every round of the wound electrode body in the part where
battery. The battery according to claim 1, wherein the length of the main body portion of the negative electrode plate in the winding axis direction is 20 cm or more. A height T1 of the wound electrode body in a portion where the first long end side is located is higher than a height T2 of the wound electrode body in a portion where the second long end side is located. The battery according to claim 1 or 2. Ratio of the height T1 of the wound electrode body at the portion where the first long side is located to the height T2 of the wound electrode body at the portion where the second long side is located (T1/T2) The battery according to claim 3, wherein is 100.1% or more and 105% or less. The positive electrode plate has a positive electrode core and a positive electrode active material layer formed on the positive electrode core,
A positive electrode tab is provided at one end in the winding axis direction of the positive electrode plate, and the positive electrode tab is provided with the positive electrode core exposed without the positive electrode active material layer formed thereon;
A negative electrode tab group in which a plurality of the negative electrode tabs are stacked is disposed at one end of the wound electrode body in the winding axis direction,
A positive electrode tab group in which a plurality of the positive electrode tabs are stacked is arranged at the other end in the winding axis direction of the wound electrode body,
The negative electrode tab group is bent while being joined to a negative electrode current collector that is a conductive member, and the positive electrode tab group is bent while being joined to a positive electrode current collector that is a conductive member. The battery according to any one of claims 1 to 4. The battery according to any one of claims 1 to 5, wherein a plurality of the wound electrode bodies are arranged inside the square exterior body. In the wound electrode body, a thickness W1 of the wound electrode body at a portion where the first long end side is located is equal to a thickness W2 of the wound electrode body at a portion where the second long end side is located. A battery according to any one of claims 1 to 6, which is different. The sealing plate has a liquid injection hole for injecting a non-aqueous electrolyte,
The liquid injection hole is sealed with a sealing member,
Any one of claims 1 to 7, wherein the liquid injection hole is arranged on a side opposite to a side where the negative electrode tab is arranged with respect to the center of the sealing plate in the longitudinal direction of the sealing plate. Batteries listed in . The battery according to any one of claims 1 to 8, wherein the wound electrode body is arranged such that an upper end side of the wound electrode body is inclined with respect to the bottom wall. A square exterior body having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall. and,
a sealing plate that seals the opening;
a flat wound electrode body housed inside the square exterior body, in which a band-shaped positive electrode plate and a band-shaped negative electrode plate are wound with a band-shaped separator interposed therebetween;
A battery comprising:
The negative electrode plate has a main body having a negative electrode core and a negative electrode active material layer formed on the negative electrode core,
The main body portion has a first long end side and a second long end side in the winding axis direction,
A negative electrode tab in which the negative electrode core is exposed without forming the negative electrode active material layer is provided on the first long end side,
The wound electrode body is arranged with a winding axis aligned with the bottom wall of the square exterior body,
In the wound electrode body, when the direction perpendicular to the bottom wall is the height direction,
A height T1 of the wound electrode body in a portion where the first long end side is located is different from a height T2 of the wound electrode body in a portion where the second long end side is located,
When the height T1 is larger than the T2, the thickness W1 of the wound electrode body at the portion where the first long side is located is the same as the thickness W1 of the wound electrode body at the portion where the second long side is located. smaller than body thickness W2,
battery. A square exterior body having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall. and,
a sealing plate that seals the opening;
a flat wound electrode body housed inside the square exterior body, in which a band-shaped positive electrode plate and a band-shaped negative electrode plate are wound with a band-shaped separator interposed therebetween;
A battery comprising:
The negative electrode plate has a main body having a negative electrode core and a negative electrode active material layer formed on the negative electrode core,
The main body portion has a first long end side and a second long end side in the winding axis direction,
A negative electrode tab in which the negative electrode core is exposed without forming the negative electrode active material layer is provided on the first long end side;
The wound electrode body is arranged with a winding axis aligned with the bottom wall of the square exterior body,
In the wound electrode body, when the direction perpendicular to the bottom wall is the height direction,
A height T1 of the wound electrode body in a portion where the first long end side is located is different from a height T2 of the wound electrode body in a portion where the second long end side is located,
When the height T2 is larger than the T1, the size of the gap that occurs every round of the wound electrode body in the part where the second long end is located is the same as the one where the first long end is located. larger than the size of the gap that occurs every round of the wound electrode body in the part where
battery. A square exterior body having a bottom wall, a pair of first side walls extending from the bottom wall and facing each other, a pair of second side walls extending from the bottom wall and facing each other, and an opening facing the bottom wall. and,
a sealing plate that seals the opening;
a flat wound electrode body housed inside the square exterior body, in which a band-shaped positive electrode plate and a band-shaped negative electrode plate are wound with a band-shaped separator interposed therebetween;
A battery comprising:
The negative electrode plate has a main body having a negative electrode core and a negative electrode active material layer formed on the negative electrode core,
The main body portion has a first long end side and a second long end side in the winding axis direction,
A negative electrode tab in which the negative electrode core is exposed without forming the negative electrode active material layer is provided on the first long end side;
The wound electrode body is arranged with a winding axis aligned with the bottom wall of the square exterior body,
In the wound electrode body, when the direction perpendicular to the bottom wall is the height direction,
A height T1 of the wound electrode body in a portion where the first long end side is located is different from a height T2 of the wound electrode body in a portion where the second long end side is located,
When the height T2 is larger than the T1, the thickness W2 of the wound electrode body at the portion where the second long side is located is the same as the thickness W2 of the wound electrode body at the portion where the first long side is located. smaller than body thickness W1,
battery.

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