JP7628099B2 - battery - Google Patents

Description

The present invention relates to a battery.

Conventionally, a battery has been known that includes an electrode body having an electrode, a battery case that houses the electrode body, a current collecting member electrically connected to the electrode within the battery case, and a terminal that is electrically connected to the current collecting member within the battery case and extends outside the battery case. In this type of battery, the electrode may be provided with multiple electrode tabs for current collection, and the electrode and the current collecting member may be electrically connected via the multiple electrode tabs (see, for example, Patent Documents 1 to 3).

Patent No. 7035348 Patent No. 7027792 International Publication No. 2018/021372

In recent years, the capacity of batteries mounted on vehicles and the like has been increasing. As the size of the electrodes increases, the number of electrode tabs attached to the electrodes increases from the viewpoint of reducing resistance. According to the inventor's study, as a result, there was a problem that the electrode tabs tend to become uneven, making it difficult to stably join them to the current collecting member. In addition, as the size of the electrode body increases, the area of the end face of the electrode body (i.e., the laminated surface on which the electrodes are laminated) becomes larger. As a result, there was also a problem that foreign matter such as metal powder is likely to enter the electrode body from the end face, for example, when joining members together in the manufacturing process. Therefore, even if the number of electrode tabs increases with the increase in capacity, it is required to provide a highly reliable battery that ensures the bond between the electrode tabs and the current collecting member and suppresses the intrusion of foreign matter into the electrode body.

The present invention was made in consideration of the above circumstances, and its main objective is to provide a highly reliable battery.

The present invention provides a battery comprising one or more electrode bodies including a first electrode and a second electrode, a battery case housing the electrode bodies, a plurality of first electrode tabs connected to the first electrode and disposed at an end of the electrode body, a current collector connected to the plurality of first electrode tabs, a fixing member bundling the plurality of first electrode tabs between a portion connected to the first electrode and a portion connected to the current collector, and one or more insulating members disposed between a first surface of the battery case and the electrode body. The insulating member has a through hole, and the plurality of first electrode tabs pass through the through hole of the insulating member.

By bundling the multiple first electrode tabs with a fixing member as described above, it is possible to suppress variation in the multiple first electrode tabs. This allows the multiple first electrode tabs to be stably joined to the current collecting member, improving the reliability of the joint. In addition, an insulating member is disposed between the battery case and the electrode body, and the first electrode tabs pass through the through holes of the insulating member, which effectively prevents foreign matter from entering the electrode body from the end surface. As described above, the present invention can realize a highly reliable battery.

FIG. 1 is a perspective view illustrating a battery according to a first embodiment. FIG. 2 is a schematic vertical cross-sectional view taken along line II-II in FIG. FIG. 3 is a schematic cross-sectional view taken along line III-III in FIG. FIG. 4 is a schematic vertical cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a schematic diagram showing the configuration of the electrode body. FIG. 6 is a schematic diagram illustrating the bonding process. FIG. 7 is a view corresponding to FIG. 4 according to the second embodiment. FIG. 8 is a schematic diagram illustrating the bonding step according to the second embodiment.

Some preferred embodiments of the technology disclosed herein will be described below with reference to the drawings. It should be noted that matters other than those specifically mentioned in this specification and necessary for implementing the technology disclosed herein (for example, the general configuration and manufacturing process of a battery that do not characterize the technology disclosed herein) can be understood as design matters for a person skilled in the art based on the prior art in the field. The technology disclosed here can be implemented based on the contents disclosed in this specification and the technical common sense in the field. It should be noted that the notation "A to B" indicating a range in this specification includes the meaning of "A or more and B or less", as well as "greater than A" and "less than B".

In this specification, the term "battery" refers to any power storage device capable of extracting electrical energy, and is a concept that includes primary and secondary batteries. In addition, in this specification, the term "secondary battery" refers to any power storage device that can be repeatedly charged and discharged by the movement of charge carriers between the positive and negative electrodes via an electrolyte. The electrolyte may be any of a liquid electrolyte (electrolytic solution), a gel electrolyte, and a solid electrolyte. Secondary batteries include so-called storage batteries (chemical batteries) such as lithium-ion secondary batteries and nickel-metal hydride batteries, as well as capacitors (physical batteries) such as electric double-layer capacitors.

First Embodiment
FIG. 1 is a perspective view showing a battery 100. FIG. 2 is a schematic longitudinal sectional view taken along line II-II in FIG. 1. FIG. 3 is a schematic transverse sectional view taken along line III-III in FIG. 1. FIG. 4 is a schematic longitudinal sectional view taken along line IV-IV in FIG. 2. In the following description, the symbols L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom. In addition, the symbol X in the drawings indicates the short side direction (thickness direction) of the battery 100, the symbol Y indicates the long side direction of the battery 100 perpendicular to the short side direction, and the symbol Z indicates the up-down direction of the battery 100. However, these directions are merely for convenience of description 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, a plurality of electrode bodies 20 (see also FIG. 3 and FIG. 4), a positive terminal 30, a negative terminal 40, a positive current collecting member 50, a negative current collecting member 60, a plurality of fixing members 70 (see also FIG. 4), and an insulating member 80 (see also FIG. 4). Although not shown, the battery 100 further includes an electrolyte. The battery 100 is a non-aqueous electrolyte secondary battery. The battery 100 is preferably a secondary battery such as a lithium ion secondary battery.

The battery case 10 is a housing that houses the electrode body 20. As shown in FIG. 1, the battery case 10 has a flat, bottomed rectangular parallelepiped (square) outer shape. The battery 100 is preferably a square battery having a square battery case 10. 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 metal, and more preferably made of, for example, aluminum, aluminum alloy, iron, iron alloy, etc. As shown in FIG. 2, the battery case 10 includes an exterior body 12 having an opening 12h, and a sealing plate (lid body) 14 that seals the opening 12h. The battery case 10 preferably includes an exterior body 12 and a sealing plate 14. The exterior body 12 and the sealing plate 14 have sizes according to the size of the electrode body 20, the number of electrodes to be accommodated (one or more; here, more than one), etc.

The exterior body 12 is a bottomed, rectangular container having an opening 12h on the upper surface. As shown in FIG. 1, the exterior body 12 includes a bottom wall 12a, a pair of long side walls 12b extending from the long side of the bottom wall 12a and facing each other, and a pair of short side walls 12c extending from the short side of the bottom wall 12a and facing each other. The bottom wall 12a is substantially rectangular. The bottom wall 12a faces the opening 12h (see FIG. 2). The long side walls 12b have a larger area than the short side walls 12c. The sealing plate 14 is a plate-like member 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 is substantially rectangular. The sealing plate 14 is an example of a "first surface". The battery case 10 is integrated by joining (e.g., welding) the sealing plate 14 to the periphery of the opening 12h of the exterior body 12. This makes the battery case 10 airtightly sealed (sealed).

As shown in FIG. 2, the sealing plate 14 is provided with a liquid injection hole 15, a gas exhaust valve 17, and terminal extraction holes 18 and 19. The liquid injection hole 15 is a through hole for injecting electrolyte into the battery case 10 after the sealing plate 14 is assembled to the exterior body 12. The liquid injection hole 15 is sealed with a sealing member 16 after the electrolyte is injected. The gas exhaust valve 17 is a thin-walled portion that is configured to break when the pressure inside the battery case 10 reaches or exceeds a predetermined value, thereby discharging gas inside the battery case 10 to the outside. The terminal extraction holes 18 and 19 are formed at both ends of the sealing plate 14 in the long side direction Y. The terminal extraction holes 18 and 19 penetrate the sealing plate 14 in the vertical direction Z.

The positive terminal 30 is attached to one end of the sealing plate 14 in the long side direction Y (the left end in Figs. 1 and 2). The negative terminal 40 is attached to the other end of the sealing plate 14 in the long side direction Y (the right end in Figs. 1 and 2). The positive terminal 30 and the negative terminal 40 are preferably attached to the sealing plate 14. The positive terminal 30 and the negative terminal 40 are inserted into the terminal pull-out holes 18, 19, and are partially exposed on the surface of the sealing plate 14. The positive terminal 30 and the negative terminal 40 are connected to other secondary batteries or external devices via external connection members such as bus bars.

As shown in FIG. 2, the positive electrode terminal 30 is electrically connected to the positive electrode 22 (see FIG. 5) of the electrode body 20 inside the battery case 10 via the positive electrode current collecting member 50 and the positive electrode tab group 25. The positive electrode terminal 30 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy. The positive electrode terminal 30 is insulated from the sealing plate 14 by a gasket 92. The gasket 92 is preferably made of resin.

The negative electrode terminal 40 is electrically connected to the negative electrode 24 (see FIG. 5) of the electrode body 20 inside the battery case 10 via the negative electrode current collecting member 60 and the negative electrode tab group 27. 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 is insulated from the sealing plate 14 by a gasket 92.

As shown in Figures 3 and 4, in the battery 100 of this embodiment, multiple (specifically, two) electrode bodies 20 are housed in the battery case 10. However, the number of electrode bodies 20 arranged in one battery case 10 is not particularly limited, and may be three or more, or may be one. The multiple electrode bodies 20 are arranged inside the battery case 10 while being covered with an electrode body holder 29 made of a resin sheet. This prevents the electrode bodies 20 from coming into direct contact with the exterior body 12.

The material of the electrode holder 29 is not particularly limited as long as it has a predetermined insulating property. Examples of such materials include synthetic resin materials such as polyolefin resins such as polypropylene (PP) and polyethylene (PE), and fluorine-based resins such as perfluoroalkoxyalkane and polytetrafluoroethylene (PTFE). As shown in FIG. 4, it is preferable that the upper end of the electrode holder 29 is approximately aligned in the vertical direction Z with the lower end of the fixing member 70 described later.

Figure 5 is a schematic diagram showing the configuration of the electrode body 20. Note that the symbol LD in Figure 5 and other figures indicates the longitudinal direction (i.e., the transport direction) of the electrode body 20, which is manufactured in a strip shape. The symbol WD is a direction approximately perpendicular to the longitudinal direction LD and indicates the winding axis direction of the electrode body 20. The winding axis direction WD is approximately parallel to the vertical direction Z of the battery 100.

As shown in FIG. 5, the electrode body 20 is a wound electrode body in which a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 are stacked in an insulated state via two strip-shaped separators 26, and wound in the longitudinal direction around the winding axis WL. However, the electrode body 20 may be a laminated electrode body in which multiple square-shaped (typically rectangular) positive electrodes and multiple square-shaped (typically rectangular) negative electrodes are stacked in an insulated state. As shown in FIG. 2, the end faces of the electrode body 20 (i.e., the stacking surfaces on which the positive electrode 22 and the negative electrode 24 are stacked, both ends in the winding axis direction WD in FIG. 5) face the bottom wall 12a and the sealing plate 14. A positive electrode tab group 25 and a negative electrode tab group 27, which will be described later, protrude from the upper part of the wound electrode body 20. The battery 100 has a so-called upper tab structure in which a positive electrode tab group 25 and a negative electrode tab group 27 are located above the wound electrode body 20. One of the positive electrode 22 and the negative electrode 24 is an example of a first electrode, and the other of the positive electrode 22 and the negative electrode 24 is an example of a second electrode.

As shown in FIG. 3, the electrode body 20 has a flat outer shape. The electrode body 20 is preferably flat. The flat electrode body 20 has a pair of curved portions 20r with curved outer surfaces and a pair of flat portions 20f with flat outer surfaces that connect the pair of curved portions 20r. The electrode body 20 is accommodated inside the battery case 10 so that the winding axis direction WD is approximately aligned with the up-down direction Z. The pair of curved portions 20r face a pair of short side walls 12c of the exterior body 12. The pair of flat portions 20f face a pair of long side walls 12b of the exterior body 12.

As shown in FIG. 5, the positive electrode 22 is a strip-shaped member. The positive electrode 22 includes a strip-shaped positive electrode 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 collector 22c. From the viewpoint of battery performance, the positive electrode active material layer 22a is preferably formed on both sides of the positive electrode collector 22c. However, the positive electrode protective layer 22p is not essential and may be omitted in other embodiments.

The components constituting the positive electrode 22 may be any conventionally known material that can be used in general batteries (e.g., lithium ion secondary batteries) without any particular restrictions. For example, the positive electrode current collector 22c is preferably made of a conductive metal such as aluminum, an aluminum alloy, nickel, or stainless steel, and is a metal foil, specifically an aluminum foil, in this case.

In the electrode body 20, as shown in FIG. 5, a plurality of positive electrode tabs 22t protrude from a base connected to one end side in the winding axis direction WD toward the outside (left side in FIG. 5). The "base" is the boundary between the end side of the positive electrode 22 and the positive electrode tab 22t. The plurality of positive electrode tabs 22t are provided (intermittently) at a predetermined interval along the longitudinal direction LD. The number of positive electrode tabs 22t attached to one electrode body 20 may be approximately several tens of sheets or more, for example, about 40 to 60 sheets. The plurality of positive electrode tabs 22t are each connected to the positive electrode 22. Here, the positive electrode tab 22t is a part of the positive electrode 22. The positive electrode tab 22t is an area where the positive electrode active material layer 22a is not formed. The positive electrode current collector 22c is exposed to at least a part of the positive electrode tab 22t. However, the positive electrode tab 22t may be a member separate from the positive electrode 22. Providing multiple positive electrode tabs 22t can reduce unevenness in resistance and potential within the positive electrode 22. The positive electrode tab 22t is an example of a first electrode tab.

Here, the positive electrode tab 22t is substantially rectangular. The protruding length of the positive electrode tab 22t (the vertical length protruding from the base in the winding axis direction WD) may be longer than the electrode tabs disclosed in, for example, Patent Documents 1 to 3, and may be approximately 3 mm or more, typically 4 to 10 mm, for example, about 5 to 8 mm. The width of the positive electrode tab 22t (the length in the longitudinal direction LD) is typically shorter than the protruding length of the positive electrode tab 22t, and may be approximately 15 mm or more, for example, 20 to 40 mm. The multiple positive electrode tabs 22t may differ from each other in size and shape.

The positive electrode tabs 22t are stacked at one end of the electrode body 20 in the winding axis direction WD and bundled by a fixing member 70 described later to form a positive electrode tab group 25 (see Figures 2 and 4). The positive electrode tabs 22t are bent and curved. The tips of the positive electrode tabs 22t are joined to the positive electrode current collector 50. It is preferable that the positive electrode tabs 22t are joined to the positive electrode current collector 50 in a bent and curved state. The positive electrode tabs 22t (positive electrode tab group 25) are electrically connected to the positive electrode terminal 30 via the positive electrode current collector 50.

As shown in FIG. 5, the positive electrode active material layer 22a is provided in a strip shape along the longitudinal direction LD of the 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) that can reversibly store and release charge carriers. The positive electrode active material layer 22a may contain any component other than the positive electrode active material, such as a conductive material, a binder, various additive components, etc. 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.

The positive electrode protective layer 22p is a layer configured to have lower electrical conductivity than the positive electrode active material layer 22a. As shown in FIG. 5, the positive electrode protective layer 22p is provided in a strip shape along the longitudinal direction LD of the positive electrode collector 22c. The positive electrode protective layer 22p is provided at the boundary between the positive electrode collector 22c and the positive electrode active material layer 22a in the winding axis direction WD. The positive electrode protective layer 22p is provided here at one end of the positive electrode collector 22c in the winding axis direction WD, specifically, at the end on the side where the positive electrode tab 22t is located (the left end in FIG. 5). By providing the positive electrode protective layer 22p, it is possible to prevent the positive electrode 22 from directly contacting the negative electrode active material layer 24a when the separator 26 is damaged, and the battery 100 from being internally short-circuited.

The positive electrode protective layer 22p contains an insulating inorganic filler. An example of an inorganic filler is ceramic particles such as alumina. The positive electrode protective layer 22p may contain optional components other than the inorganic filler, such as a binder, a conductive material, and various additive components. The binder and conductive material may be the same as those exemplified as those that may be contained in the positive electrode active material layer 22a.

As shown in FIG. 5, the negative electrode 24 is a strip-shaped member. The negative electrode 24 includes a strip-shaped negative electrode collector 24c and a negative electrode active material layer 24a fixed to at least one surface of the negative electrode collector 24c. From the viewpoint of battery performance, it is preferable that the negative electrode active material layer 24a is formed on both sides of the negative electrode collector 24c.

The components constituting the negative electrode 24 may be any conventionally known material that can be used in general batteries (e.g., lithium ion secondary batteries) without any particular restrictions. For example, the negative electrode current collector 24c is preferably made of a conductive metal such as copper, a copper alloy, nickel, or stainless steel, and is a metal foil, specifically a copper foil, in this case.

In the electrode body 20, as shown in FIG. 5, a plurality of negative electrode tabs 24t protrude from a base connected to one end side in the winding axis direction WD toward the outside (left side in FIG. 5). The plurality of negative electrode tabs 24t are provided (intermittently) at a predetermined interval along the longitudinal direction LD. In the winding axis direction WD, the negative electrode tabs 24t are provided at the end on the same side (left side in FIG. 5) as the positive electrode tabs 22t. The number of negative electrode tabs 24t attached to one electrode body 20 is approximately equal to the number of positive electrode tabs 22t, and may be approximately several tens of sheets or more, for example, about 40 to 60 sheets. The plurality of negative electrode tabs 24t are each connected to the negative electrode 24. Here, the negative electrode tab 24t is a part of the negative electrode 24. Here, the negative electrode tab 24t is an area where the negative electrode active material layer 24a is not formed and the negative electrode current collector 24c is exposed. However, the negative electrode tab 24t may be a separate member from the negative electrode 24. By providing multiple negative electrode tabs 24t, it is possible to reduce unevenness in the resistance and potential within the negative electrode 24.

Here, the negative electrode tab 24t is substantially rectangular. The protruding length of the negative electrode tab 24t (the vertical length protruding from the base in the winding axis direction WD) may be longer than the electrode tabs disclosed in, for example, Patent Documents 1 to 3, and may be approximately 3 mm or more, typically 4 to 10 mm, for example, about 5 to 8 mm. The width of the negative electrode tab 24t (the length in the longitudinal direction LD) is typically shorter than the protruding length of the negative electrode tab 24t, and may be approximately 15 mm or more, for example, 20 to 40 mm. The multiple negative electrode tabs 24t may differ from each other in size and shape.

The negative electrode tabs 24t are stacked at one end of the electrode body 20 in the winding axis direction WD and bundled by a fixing member 70 described later to form a negative electrode tab group 27 (see Figures 2 and 4). Although not shown, the negative electrode tabs 24t are bent and curved, similar to the positive electrode tabs 22t. The tips of the negative electrode tabs 24t are joined to the negative electrode current collector 60. It is preferable that the negative electrode tabs 24t are joined to the negative electrode current collector 60 in a bent and curved state. The negative electrode tabs 24t (negative electrode tab group 27) are electrically connected to the positive electrode terminal 30 via the negative electrode current collector 60.

As shown in FIG. 5, the negative electrode active material layer 24a is provided in a band shape along the longitudinal direction LD of the negative electrode current collector 24c. The negative electrode active material layer 24a contains a negative electrode active material (e.g., a carbon material such as graphite) that can reversibly store and release charge carriers. The negative electrode active material layer 24a may contain optional components other than the negative electrode active material, such as a binder, a dispersant, and various additive components. As the binder, for example, rubbers such as styrene butadiene rubber (SBR) can be used. As the dispersant, for example, celluloses such as carboxymethyl cellulose (CMC) can be used.

As shown in FIG. 5, the separator 26 is a strip-shaped member. The separator 26 is a member 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. Here, the separator 26 constitutes the outer surface of the electrode body 20. As the separator 26, for example, a resin porous sheet made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is suitable. The separator 26 may have a substrate portion made of a resin porous sheet and a heat resistance layer (Heat Resistance Layer: HRL) formed on at least one surface of the substrate portion. The heat resistance layer is a layer containing an inorganic filler. As the inorganic filler, for example, alumina, boehmite, aluminum hydroxide, titania, etc. may be used.

The electrolyte may be any electrolyte used in a general battery (e.g., a lithium ion secondary battery) without any particular limitation. An example of the electrolyte is a non-aqueous electrolyte in which a supporting salt is dissolved in a non-aqueous solvent. An example of the non-aqueous solvent is a carbonate-based solvent such as ethylene carbonate, dimethyl carbonate, or ethyl methyl carbonate. An example of the supporting salt is a fluorine-containing lithium salt such as _LiPF6 . The electrolyte may contain an additive as necessary. However, the electrolyte may be in a solid state (solid electrolyte) and integrated with the electrode body 20.

The positive electrode current collecting member 50 is a conductive member and constitutes a current path. The positive electrode current collecting member 50 is attached to the sealing plate 14 here. The positive electrode current collecting member 50 electrically connects the positive electrode tab group 25 of the electrode body 20 and the positive electrode terminal 30. As shown in FIG. 2, the positive electrode current collecting member 50 has a plate-shaped first region extending in the long side direction Y along the inner side surface of the sealing plate 14. The positive electrode current collecting member 50 here is composed of the first region. It is preferable that the positive electrode current collecting member 50 has a first region arranged along the surface of the sealing plate 14 on the electrode body 20 side (the lower surface in FIG. 2). This makes it possible to effectively suppress the intrusion of foreign matter into the electrode body 20 described later. One end (the right side in FIG. 2) of the positive electrode current collecting member 50 (specifically the first region) in the long side direction Y is electrically connected to the positive electrode tab group 25, i.e., the stacked multiple positive electrode tabs 22t. The positive electrode current collecting member 50 and the positive electrode tab group 25 are preferably joined (e.g., ultrasonically welded).

The other end (left side in FIG. 2) of the positive current collecting member 50 (specifically, the first region) in the long side direction Y is electrically connected to the lower end 30c of the positive terminal 30. The positive current collecting member 50 is preferably made of a metal with excellent conductivity, for example, aluminum or an aluminum alloy. The positive current collecting member 50 may be made of the same type of metal as the positive tab 22t and/or the positive terminal 30.

The negative electrode current collecting member 60 is a conductive member and constitutes a current path. The negative electrode current collecting member 60 is attached to the sealing plate 14 here. The negative electrode current collecting member 60 electrically connects the negative electrode tab group 27 of the electrode body 20 and the negative electrode terminal 40. As shown in FIG. 2, the negative electrode current collecting member 60 has a plate-shaped first region extending in the long side direction Y along the inner side surface of the sealing plate 14. The negative electrode current collecting member 60 here is composed of the first region. It is preferable that the negative electrode current collecting member 60 has a first region arranged along the surface of the sealing plate 14 on the electrode body 20 side (the lower surface in FIG. 2). One end of the negative electrode current collecting member 60 (specifically the first region) in the long side direction Y (the left side in FIG. 2) is electrically connected to the negative electrode tab group 27, i.e., the stacked multiple negative electrode tabs 24t. It is preferable that the negative electrode current collecting member 60 and the negative electrode tab group 27 are joined (for example, ultrasonically welded).

The other end (the right side in FIG. 2) of the negative electrode current collecting member 60 (specifically, the first region) in the long side direction Y is electrically connected to the lower end 40c of the negative electrode terminal 40. The negative electrode current collecting member 60 is preferably made of a metal with excellent conductivity, for example, copper or a copper alloy. The negative electrode current collecting member 60 may be made of the same type of metal as the negative electrode tab 24t and/or the negative electrode terminal 40.

The positive electrode current collecting member 50 and the negative electrode current collecting member 60 are each insulated from the inner surface of the sealing plate 14 by an internal insulating member 94. The internal insulating member 94 is preferably made of resin. The resin internal insulating member 94 is preferably disposed between the positive electrode current collecting member 50 and the sealing plate 14. The resin internal insulating member 94 is preferably disposed between the negative electrode current collecting member 60 and the sealing plate 14.

The multiple fixing members 70 are for bundling the multiple positive electrode tabs 22t and the multiple negative electrode tabs 24t. As shown in FIG. 2, the multiple fixing members 70 are attached to the positive electrode tab group 25 (multiple positive electrode tabs 22t) and the negative electrode tab group 27 (multiple negative electrode tabs 24t) of the electrode body 20, respectively. As shown in FIG. 4, the multiple fixing members 70 are attached to each electrode body 20. The number of fixing members 70 is typically the number of electrode bodies 20 x 2 (for the positive electrode tabs 22t and the negative electrode tabs 24t). The number of fixing members 70 is four here. In the following, the multiple positive electrode tabs 22t will be described in detail as an example, but the fixing members 70 can also be attached to the multiple negative electrode tabs 24t in the same way. It is preferable that the technology disclosed herein be applied to the multiple positive electrode tabs 22t and the multiple negative electrode tabs 24t, respectively.

As shown in FIG. 4, the multiple positive electrode tabs 22t are maintained in an integrated state by bundling the portion (root portion) connected to the positive electrode 22 and the portion connected to the positive electrode current collecting member 50 with a fixing member 70. According to the inventor's study, if the number of positive electrode tabs 22t is about several sheets, it is easy to directly join (typically weld) them to the positive electrode current collecting member 50. However, in a high-capacity battery 100, if the number of positive electrode tabs 22t is several tens or more, the positive electrode tabs 22t are likely to vary, and it becomes difficult to stably ensure the joining with the positive electrode current collecting member 50. Therefore, in the technology disclosed herein, the multiple positive electrode tabs 22t are bundled using the fixing member 70 to form a positive electrode tab group 25. This allows the multiple positive electrode tabs 22t to be stably joined to the positive electrode current collecting member 50, and the joining (typically weldability) can be improved. As a result, the conduction reliability of the battery 100 can be improved.

The number of positive electrode tabs 22t bound by the fixing member 70 may be more than one (two or more). From the viewpoint of better exerting the effects of the technology disclosed herein, it is preferable that more than half of the total number of positive electrode tabs 22t attached to one electrode body 20 be bound by one fixing member 70. As shown in FIG. 4, all positive electrode tabs 22t attached to one electrode body 20 are bound by one fixing member 70. The fixing member 70 may be a conductive member and may constitute a current path from the positive electrode 22 to the positive electrode current collecting member 50. The fixing member 70 is preferably made of a metal having high electrical conductivity.

The fixing member 70 is preferably a clamping member that holds the multiple positive electrode tabs 22t by clamping them. When the fixing member 70 is a clamping member, the multiple positive electrode tabs 22t can be easily folded in a bundled state, improving workability. In addition, welding is not required, and the generation of foreign matter such as metal powder can be suppressed when the multiple positive electrode tabs 22t are fixed to the fixing member 70. In the long side direction Y, the width of the fixing member 70 is preferably larger than the width of the positive electrode tabs 22t. The width of the fixing member 70 in the long side direction Y is larger than the multiple positive electrode tabs 22t, and can be, for example, 15 mm or more, about 20 to 40 mm. The fixing member 70 is preferably one that can stack the multiple positive electrode tabs 22t and maintain a state parallel to the upper end of the electrode body 20 in the long side direction Y.

As shown in FIG. 2, one example of the fixing member 70 is a part having a YZ plane portion extending in the long side direction Y and the vertical direction Z, such as a hollow cylindrical oval sleeve having a tunnel-shaped through hole in the vertical direction Z. When an oval sleeve is used as the fixing member 70, the tips of the positive electrode tabs 22t are inserted into the through holes of the oval sleeve and then crimped to fix the positive electrode tabs 22t to the oval sleeve. Another example of the fixing member 70 is a plate-shaped clip member having a fixing portion on one or both sides in the long side direction Y, such as a clip it.

As shown in FIG. 4, the fixing member 70 is preferably located at the center M of the electrode body 20 in the short side direction X. This ensures that even if the electrode body 20 swells during charging and discharging, electrical continuity with the positive electrode tab 22t located at the outer edge of the electrode body 20 can be maintained. The multiple positive electrode tabs 22t are preferably bundled together at their portions that are approximately perpendicular to the sealing plate 14 by the fixing member 70. This effectively prevents foreign matter from entering the electrode body 20, which will be described later. In this specification, "approximately perpendicular" refers to approximately 92±15° (75 to 105°), preferably 92±10° (80 to 100°), for example 92±5° (85 to 95°).

It is preferable that the positive electrode tabs 22t are connected to the positive electrode current collecting member 50 in a state in which the side (tip e side) closer to the positive electrode current collecting member 50 than the part bundled by the fixing member 70 is bent. This makes it possible to expand the storage space of the electrode body 20 and increase the energy density of the battery 100. It is preferable that the positive electrode tabs 22t protruding from the upper end of the fixing member 70 are bent (curved) into a substantially L-shape in the state in which they are bundled by the fixing member 70. That is, it is preferable that the positive electrode tabs 22t have a curved portion 25b on the side (tip e side) closer to the positive electrode current collecting member 50 than the part bundled by the fixing member 70. This makes it easier for the positive electrode tabs 22t to be bundled together, and the bondability (typically weldability) with the positive electrode current collecting member 50 attached to the sealing plate 14 can be further improved. It is preferable that the root parts of the positive electrode tabs 22t that are bundled and bent are parallel to each other.

The insulating member 80 is a cover that covers at least a portion of the end face of the electrode body 20. As shown in FIG. 2, the insulating member 80 is disposed between the inner surface of the sealing plate 14 (the lower surface in FIG. 2) and the electrode body 20. More specifically, it is disposed between the positive electrode current collecting member 50 attached to the sealing plate 14 and the electrode body 20. Here, there is one insulating member 80. However, as in the second embodiment described later, one battery 100 may be provided with multiple insulating members 80.

As shown in FIG. 4, the insulating member 80 has through holes 80h. The number of through holes 80h in the insulating member 80 is typically the number of electrode bodies 20 times 2 (for positive electrode tabs 22t and negative electrode tabs 24t). The number of through holes 80h can be the same as the number of fixing members 70. In this example, the number of through holes 80h is four. The multiple positive electrode tabs 22t are bundled with the fixing members 70 and organized as a positive electrode tab group 25, and pass through the through holes 80h in the insulating member 80.

The insulating member 80 is disposed between the sealing plate 14 and the electrode body 20, and the multiple positive electrode tabs 22t pass through the through holes 80h provided in the insulating member 80, thereby preventing conductive foreign matter that may lead to a decrease in battery performance such as a voltage drop from entering the inside of the electrode body 20 from the upper end surface of the electrode body 20. Even if the electrode body 20 moves toward the sealing plate 14 due to an external force such as vibration or impact during use of the battery 100, the load on the positive electrode tab group 25 can be reduced. Furthermore, the electrode body 20 can be prevented from coming into contact with a member attached to the sealing plate 14 (e.g., the positive electrode current collecting member 50) and being damaged.

The insulating member 80 is preferably sized to cover the entire upper end surface of the electrode body 20 in the XY plane view. In the XY plane view, the outer edge of the insulating member 80 is preferably larger than the outer edge of the electrode body holder 29. This can prevent the electrode body 20 and the electrode body holder 29 from coming into direct contact with each other. The insulating member 80 may be disposed inside the electrode body holder 29 or outside the electrode body holder 29. In other words, in the vertical direction Z, the upper end of the electrode body holder 29 may be located below the insulating member 80 or may be located above the insulating member 80. The insulating member 80 may be fixed to the electrode body 20 or the electrode body holder 29 by a fixing means such as tape. The insulating member 80 may be integral with the electrode body holder 29 and may be a part of the electrode body holder 29.

The insulating member 80 is preferably made of resin. The material of the insulating member 80 may be the same as the material exemplified for the electrode body holder 29. The material of the insulating member 80 may be the same as the material of the electrode body holder 29, or may be different. The insulating member 80 is preferably made of a material and has a thickness such that, for example, the ends in the short side direction X and/or long side direction Y do not bend or curl due to their own weight, and the XY plane can be stably maintained in a flat shape. Therefore, as shown in FIG. 4 etc., the insulating member 80 is preferably thicker than the electrode body holder 29.

As shown in FIG. 4, in the thickness direction of the battery 100, in other words, in the direction in which the multiple positive electrode tabs 22t are stacked (short side direction X in FIG. 4), when the width of the through hole 80h of the insulating member 80 is W1 and the total thickness of the bundled portion of the multiple positive electrode tabs 22t is T1, it is preferable that the above W1 and the above T1 satisfy the following formula (1): (W1/T1)<10;. By minimizing the size of the through hole 80h, it is possible to effectively prevent foreign matter from passing through the through hole 80h and entering the electrode body 20. The above formula (1) is typically 1<(W1/T1). It is more preferable that the above formula (1) satisfies (W1/T1)<5.

As shown in FIG. 4, it is preferable that at least a part of the fixing member 70 is disposed inside the through hole 80h. This can more effectively prevent foreign matter from passing through the through hole 80h and entering the electrode body 20. In this case, when the width of the through hole 80h of the insulating member 80 is W1 and the width of the fixing member 70 is W2 in the thickness direction of the battery 100, in other words, in the direction in which the multiple positive electrode tabs 22t are stacked (short side direction X in FIG. 4), it is preferable that the above W1 and the above W2 satisfy the following formula (2): (W1/W2)<5;. This can further suppress the intrusion of foreign matter into the electrode body 20 at a high level. The above formula (2) is typically 1<(W1/W2). It is more preferable that the above formula (2) satisfies (W1/W2)<3;.

The battery 100 can be manufactured, for example, by a method including the following steps, typically in this order: (Step 1) electrode preparation step; (Step 2) electrode assembly fabrication step; (Step 3) tab fixing step; (Step 4) electrode assembly housing step; (Step 5) bonding step; and (Step 6) sealing step. The manufacturing method disclosed herein may further include other steps at any stage.

(Step 1) In the electrode preparation process, a strip-shaped positive electrode 22 having multiple positive electrode tabs 22t and a strip-shaped negative electrode 24 having multiple negative electrode tabs 24t are prepared. (Step 2) In the electrode body preparation process, first, the strip-shaped positive electrode 22 and the strip-shaped negative electrode 24 are stacked with a strip-shaped separator 26 interposed therebetween, and then wound in the longitudinal direction around the winding axis WL to form a cylindrical shape. At this time, the multiple positive electrode tabs 22t and the multiple negative electrode tabs 24t are adjusted so that they protrude from the same end side and are stacked at different positions. Next, the electrode body (cylindrical body) wound into a cylindrical shape is, for example, press-molded into a flat shape to produce a flat-shaped electrode body 20 (see FIG. 5).

(Step 3) In the tab fixing process, the multiple positive electrode tabs 22t and the multiple negative electrode tabs 24t are bundled with the fixing member 70, respectively, and the collected foil state is fixed. This process is preferably performed simultaneously with the molding of the electrode body 20. The fixing position of the fixing member 70 is preferably as close as possible to the electrode body 20, from the viewpoint of expanding the storage space of the electrode body 20, etc. The multiple positive electrode tabs 22t are bundled with the fixing member 70 and integrated into the positive electrode tab group 25. Similarly, the multiple negative electrode tabs 24t are bundled with the fixing member 70 and integrated into the negative electrode tab group 27.

(Step 4) In the electrode assembly housing process, the electrode assembly 20 is inserted into the electrode assembly holder 29, and then the electrode assembly 20 wrapped in the electrode assembly holder 29 is housed in the exterior body 12 so that the positive electrode tab group 25 and the negative electrode tab group 27 face upward. Next, an insulating member 80 having a plurality of through holes 80h is prepared, and the positive electrode tab group 25 and the negative electrode tab group 27 are inserted into the plurality of through holes 80h of the insulating member 80, respectively. As a result, the insulating member 80 is arranged to cover the upper end surface of the electrode assembly 20.

(Step 5) In the joining process, the tip side of the positive electrode tab group 25 and the tip side of the negative electrode tab group 27 protruding from the upper end of the fixing member 70 are bent into an approximately L-shape with respect to the fixing member 70. In addition, the positive electrode terminal 30, the negative electrode terminal 40, the positive electrode current collector 50, and the negative electrode current collector 60 are attached to the sealing plate 14. Next, as shown in FIG. 6, the tip of the positive electrode tab group 25 is joined (e.g., welded) to the positive electrode current collector 50 attached to the sealing plate 14. In addition, the tip of the negative electrode tab group 27 is joined to the negative electrode current collector 60 attached to the sealing plate 14. As a result, a joint (e.g., welded joint) J between the positive electrode current collector 50 and the positive electrode tab group 25 is formed, and a joint (e.g., welded joint) J between the negative electrode current collector 60 and the negative electrode tab group 27 is formed.

(Step 6) In the sealing process, the tip of the positive electrode tab group 25 and the tip of the negative electrode tab group 27 are bent and curved into a roughly U-shape, and the sealing plate 14 is fitted into the opening 12h of the exterior body 12, and the periphery of the opening 12h of the exterior body 12 and the sealing plate 14 are joined (for example, welded). This hermetically seals the battery case 10. In this manner, the battery 100 can be manufactured.

Second Embodiment
FIG. 7 is a view corresponding to FIG. 4 according to the second embodiment. As shown in FIG. 7, the battery 200 of this embodiment includes a plurality of electrode bodies and a plurality of insulating members. The plurality of electrode bodies includes a first electrode body 20a and a second electrode body 20b. The plurality of insulating members includes a first insulating member 80a and a second insulating member 80b. The first insulating member 80a and the second insulating member 80b are separate members (separate members). The number of insulating members 80 provided in one battery 200 is typically the same as the number of electrode bodies 20. The number of insulating members 80 is two here. The plurality of positive electrode tabs 22t connected to the first electrode body 20a are bundled with a fixing member 70 and pass through the through hole 80h of the first insulating member 80a. The plurality of positive electrode tabs 22t connected to the second electrode body 20b are bundled with a fixing member 70 and pass through the through hole 80h of the second insulating member 80b. This improves assembly ease and enables efficient manufacture of the battery 200. Also, inclusion of foreign matter in the electrode body 20 can be effectively prevented.

The battery 200 can be manufactured, for example, by a manufacturing method including, in this order, (step 4A) a joining step and (step 5A) an electrode assembly housing step, instead of steps 4 and 5 of the first embodiment.

(Step 4A) In the joining process, as shown in FIG. 8, a plurality of positive electrode tabs 22t and a plurality of negative electrode tabs 24t are inserted into the through holes 80h of the first insulating member 80a and the second insulating member 80b, respectively. As a result, the first insulating member 80a is installed so as to cover the upper end surface of the first electrode body 20a, and the second insulating member 80b is installed so as to cover the upper end surface of the second electrode body 20b. Next, the positive electrode terminal 30, the negative electrode terminal 40, the positive electrode current collector 50, and the negative electrode current collector 60 are attached to the sealing plate 14. Next, the tip portions of the plurality of positive electrode tabs 22t of the first electrode body 20a and the second electrode body 20b are joined (for example, welded) to the positive electrode current collector 50 attached to the sealing plate 14. In addition, the tip portions of the multiple negative electrode tabs 24t of the first electrode body 20a and the second electrode body 20b are joined (e.g., welded) to the negative electrode current collecting member 60 attached to the sealing plate 14. This forms a joint (e.g., welded joint) J between the positive electrode current collecting member 50 and the multiple positive electrode tabs 22t, and a joint (e.g., welded joint) J between the negative electrode current collecting member 60 and the multiple negative electrode tabs 24t.

(Step 5A) In the electrode assembly housing process, the tip e of the positive electrode tab group 25 and the tip e of the negative electrode tab group 27 protruding from the upper end of the fixing member 70 are each bent into a substantially L-shape relative to the fixing member 70. Next, the electrode assembly 20 is inserted into the electrode assembly holder 29, and the electrode assembly 20 wrapped in the electrode assembly holder 29 is then housed in the exterior body 12.

<Battery uses>
Although the battery 100 can be used for various purposes, it is suitable for use in applications requiring high capacity or applications in which external forces such as vibrations and shocks may be applied during use, for example, as a power source (driving power source) for a motor mounted on a moving body (typically a vehicle such as a passenger car or truck). The type of vehicle is not particularly limited, and examples thereof include a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), and a battery electric vehicle (BEV).

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.

As described above, specific aspects of the technology disclosed herein include those described in the following sections.
Item 1: A battery comprising: one or more electrode bodies including a first electrode and a second electrode; a battery case accommodating the electrode bodies; a plurality of first electrode tabs connected to the first electrode and arranged at an end of the electrode body; a current collecting member connected to the plurality of first electrode tabs; a fixing member bundling the plurality of first electrode tabs between a portion connected to the first electrode and a portion connected to the current collecting member; and one or more insulating members arranged between a first surface of the battery case and the electrode body, wherein the insulating member has a through hole, and the plurality of first electrode tabs pass through the through hole of the insulating member.
Item 2: The battery according to item 1, wherein, in a direction in which the plurality of first electrode tabs are stacked, when a width of the through hole of the insulating member is W1 and a total thickness of a bundled portion of the plurality of first electrode tabs is T1, W1 and T1 satisfy the following formula: (W1/T1)<10.
Item 3: The battery described in item 1 or 2, wherein the electrode body includes a first electrode body and a second electrode body, the insulating member includes a first insulating member and a second insulating member, the plurality of first electrode tabs connected to the first electrode body pass through the through holes of the first insulating member, and the plurality of first electrode tabs connected to the second electrode body pass through the through holes of the second insulating member.
Item 4: The battery according to any one of items 1 to 3, wherein at least a portion of the fixing member is disposed inside the through hole.
Item 5: The battery according to item 4, wherein, in a direction in which the plurality of first electrode tabs are stacked, when the width of the through hole of the insulating member is W1 and the width of the fixing member is W2, W1 and W2 satisfy the following formula: (W1/W2)<5.
Item 6: The battery according to any one of items 1 to 5, wherein the first electrode tabs are bundled together by the fixing member at portions that are approximately perpendicular to the first surface of the battery case.
Item 7: The battery according to any one of items 1 to 6, wherein the first electrode tabs are connected to the current collecting member in a bent state on the side closer to the current collecting member than the portion bundled by the fixing member.
Item 8: A battery described in any one of items 1 to 7, wherein the current collecting member has a first region arranged along the first surface of the battery case, and a plurality of the first electrode tabs are stacked and connected to the first region.

10 Battery case 12 Exterior body 14 Sealing plate 20, 20a, 20b Electrode body 22 Positive electrode 22t Positive electrode tab 24 Negative electrode 24t Negative electrode tab 70 Fixing member 80, 80a, 80b Insulating member 100, 200 Battery

Claims (12)

a first electrode body and a second electrode body each including a first electrode and a second electrode;
a battery case that accommodates the first electrode body and the second electrode body ;
a plurality of first electrode tabs of the first electrode body connected to the first electrodes and disposed at ends of the first electrode body;
a plurality of first electrode tabs of the second electrode body connected to the first electrodes and disposed at ends of the second electrode body;
a current collecting member connected to the first electrode tabs of the first electrode body and the first electrode tabs of the second electrode body ;
a first fixing member that bundles the first electrode tabs of the first electrode body between a portion connected to the first electrode and a portion connected to the current collecting member;
a second fixing member that bundles the first electrode tabs of the second electrode body between a portion connected to the first electrode and a portion connected to the current collecting member;
a first insulating member disposed between the first surface of the battery case and the first electrode body , the first insulating member having a first through hole ;
a second insulating member disposed between the first surface of the battery case and the second electrode body, the second insulating member having a second through hole;
Equipped with
the first insulating member and the second insulating member are separate parts,
the first electrode tabs of the first electrode body pass through the first through holes of the first insulating member ;
The first electrode tabs of the second electrode body pass through the second through holes of the second insulating member .
battery. In a direction in which the first electrode tabs of the first electrode body are stacked, when a width of the first through hole of the first insulating member is W1 and a total thickness of a bundled portion of the first electrode tabs of the first electrode body is T1, the W1 and the T1 satisfy the following formula: (W1/T1)<10;
10. The battery of claim 1. At least a portion of the first fixing member is disposed inside the first through hole.
3. The battery of claim 1 or 2. In a direction in which the first electrode tabs of the first electrode body are stacked, when a width of the first through hole of the first insulating member is W1 and a width of the first fixing member is W2, the width W1 and the width W2 satisfy the following formula: (W1/W2)<5;
4. The battery of claim 3 . the first electrode tabs of the first electrode body are bundled by the first fixing member at portions that are substantially perpendicular to the first surface of the battery case;
3. The battery of claim 1 or 2. the first electrode tabs of the first electrode body are connected to the current collecting member in a state in which a side closer to the current collecting member than a portion bundled by the first fixing member is bent.
3. The battery of claim 1 or 2. the current collecting member has a first region disposed along the first surface of the battery case,
The first electrode tabs of the first electrode body are stacked and connected to the first region.
3. The battery of claim 1 or 2. one or more electrode bodies including a first electrode and a second electrode;
A battery case that houses the electrode assembly;
a plurality of first electrode tabs connected to the first electrodes and disposed at ends of the electrode body;
a current collecting member connected to a plurality of the first electrode tabs;
a fixing member that bundles the first electrode tabs between a portion connected to the first electrode and a portion connected to the current collecting member;
One or more insulating members disposed between the first surface of the battery case and the electrode body;
Equipped with
The insulating member has a through hole,
the first electrode tabs pass through the through holes of the insulating member ;
At least a portion of the fixing member is disposed inside the through hole .
battery. The fixing member is a conductive member.
9. The battery of claim 8. one or more electrode bodies including a first electrode and a second electrode;
A battery case that houses the electrode assembly;
a plurality of first electrode tabs connected to the first electrodes and disposed at ends of the electrode body;
a current collecting member connected to a plurality of the first electrode tabs;
a fixing member that bundles the first electrode tabs between a portion connected to the first electrode and a portion connected to the current collecting member;
One or more insulating members disposed between the first surface of the battery case and the electrode body;
Equipped with
The insulating member has a through hole,
the first electrode tabs pass through the through holes of the insulating member ;
the first electrode tabs are connected to the current collecting member in a bent state at a side closer to the current collecting member than the portion bundled by the fixing member ;
battery. The fixing member is a conductive member.
The battery of claim 10. one or more electrode bodies including a first electrode and a second electrode;
A battery case that houses the electrode assembly;
a plurality of first electrode tabs connected to the first electrodes and disposed at ends of the electrode body;
a current collecting member connected to a plurality of the first electrode tabs;
a fixing member that bundles the first electrode tabs between a portion connected to the first electrode and a portion connected to the current collecting member;
One or more insulating members disposed between the first surface of the battery case and the electrode body;
Equipped with
The insulating member has a through hole,
the first electrode tabs pass through the through holes of the insulating member ;
The electrode body includes a first electrode body and a second electrode body,
the insulating member has a first through hole and a second through hole formed at a position spaced apart from the first through hole,
The first electrode tabs connected to the first electrode body pass through the first through holes,
The first electrode tabs connected to the second electrode body pass through the second through holes,
The first electrode tabs connected to the first electrode body and the second electrode tabs connected to the second electrode body are overlapped and joined to the current collecting member .
battery.

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