JP2024031646A - battery - Google Patents

Abstract

[Problem] To provide a highly reliable battery. A battery 100 disclosed herein includes an electrode body 20 including a first electrode and a second electrode, a battery case 10 housing the electrode body 20, and a plurality of first electrode bodies connected to the first electrode. The electrode tab 22t, the current collecting member 50 connected to the plurality of first electrode tabs 22t, the fixing member 70 that bundles the plurality of first electrode tabs 22t, the first surface 14 of the battery case 10, and the electrode body 20. The insulating member 80 has a through hole 80h, and the plurality of first electrode tabs 22t pass through the through hole 80h of the insulating member 80. [Selection diagram] Figure 4

Description

The present invention relates to batteries.

Conventionally, an electrode body having an electrode, a battery case housing the electrode body, a current collecting member electrically connected to the electrode within the battery case, and a battery case electrically connected to the current collecting member within the battery case. Batteries are known that include terminals that extend outward. In this type of battery, the electrode may be provided with a plurality of electrode tabs for collecting current, and the electrode and the current collecting member may be electrically connected via the plurality of electrode tabs (for example, Patent Document 1 (See ~3).

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

BACKGROUND ART In recent years, batteries installed in vehicles and the like have been increasing in capacity. As the size of the electrode increases accordingly, the number of electrode tabs attached to the electrode increases from the viewpoint of reducing resistance. According to the studies of the present inventors, as a result, the plurality of electrode tabs tend to vary, making it difficult to stably connect them to the current collecting member. Furthermore, as the size of the electrode body increases, the area of the end face of the electrode body (that is, the laminated surface on which the electrodes are laminated) increases. As a result, for example, when joining members together in a manufacturing process, there is a problem in that foreign matter such as metal powder is likely to enter the electrode body from the end face. Therefore, even when the number of electrode tabs increases due to higher capacity, the bonding between the electrode tabs and the current collecting member is ensured, and the contamination of foreign matter into the electrode body is suppressed, providing a highly reliable battery. is required to do so.

The present invention has been made in view of the above circumstances, and its main purpose is to provide a highly reliable battery.

According to the present invention, one or more electrode bodies including a first electrode and a second electrode, a battery case housing the electrode bodies, and a battery case connected to the first electrode and disposed at an end of the electrode body. a plurality of first electrode tabs, a current collecting member connected to the plurality of first electrode tabs, and a portion connecting the plurality of first electrode tabs to the first electrode and the current collecting member; A battery is provided, including a fixing member for bundling between the battery case and the electrode body, and one or more insulating members disposed between the 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 plurality of first electrode tabs with the fixing member as described above, variations in the plurality of first electrode tabs can be suppressed. Thereby, the plurality of first electrode tabs and the current collecting member can be stably joined, and the reliability of the joint can be improved. In addition, an insulating member is placed between the battery case and the electrode body, and the first electrode tab passes through the through hole of the insulating member, effectively suppressing foreign matter from entering the electrode body from the end surface. can. As described above, according to the present invention, a highly reliable battery can be realized.

FIG. 1 is a perspective view schematically showing 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. 1. FIG. 4 is a schematic vertical cross-sectional view taken along line IV-IV in FIG. 2. FIG. 5 is a schematic diagram showing the structure of the electrode body. FIG. 6 is a schematic diagram illustrating the bonding process. FIG. 7 is a diagram corresponding to FIG. 4 according to the second embodiment. FIG. 8 is a schematic diagram illustrating a joining process according to the second embodiment.

Hereinafter, some preferred embodiments of the technology disclosed herein will be described with reference to the drawings. It should be noted that matters other than those specifically mentioned in this specification that are necessary for implementing the technology disclosed herein (for example, the general configuration of a battery that does not characterize the technology disclosed herein) and manufacturing process) can be understood as a matter of design by a person skilled in the art based on the prior art in the field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common technical knowledge in the field. In this specification, the notation "A to B" indicating a range includes the meaning of "above A and no more than B", as well as "exceeding A" and "less than B".

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. Furthermore, in this specification, the term "secondary battery" refers to any electricity storage device that can be repeatedly charged and discharged by moving charge carriers between a positive electrode and a negative electrode via an electrolyte. The electrolyte may be a liquid electrolyte (electrolytic solution), a gel electrolyte, or a solid electrolyte. Secondary batteries include not only so-called storage batteries (chemical batteries) such as lithium ion secondary batteries and nickel-hydrogen batteries, but also capacitors (physical batteries) such as electric double layer capacitors.

<First embodiment>
FIG. 1 is a perspective view schematically showing a battery 100. 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. 1. FIG. 4 is a schematic vertical cross-sectional view taken along line IV-IV in FIG. 2. FIG. In the following description, the symbols L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom. Further, 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 orthogonal to the short side direction, and the symbol Z indicates the vertical direction of the battery 100. shows. 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, a plurality of electrode bodies 20 (see also FIGS. 3 and 4), a positive terminal 30, a negative terminal 40, a positive current collecting member 50, and a negative electrode. It includes a 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 here. 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 rectangular parallelepiped shape (square) that is flat and has a bottom. The battery 100 is preferably a prismatic battery having a prismatic battery case 10. The material of the battery case 10 may be the same as that conventionally used 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, 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 seals the opening 12h. It is preferable that the battery case 10 includes an exterior body 12 and a sealing plate 14. The exterior body 12 and the sealing plate 14 have sizes that correspond to the size of the electrode body 20 and the number (one or more, in this case, a plurality) of the electrode bodies 20 accommodated.

The exterior body 12 is a bottomed, rectangular container having an opening 12h on the top 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 long side walls 12b extending from the short side of the bottom wall 12a and facing each other. A short side wall 12c. The bottom wall 12a has a substantially rectangular shape. The bottom wall 12a faces the opening 12h (see FIG. 2). The long side wall 12b has a larger area than the short side wall 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 has a substantially rectangular shape. The sealing plate 14 is an example of a "first surface." 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. Thereby, the battery case 10 is hermetically sealed (sealed).

As shown in FIG. 2, the sealing plate 14 is provided with a liquid injection hole 15, a gas discharge valve 17, and terminal extraction holes 18 and 19. The liquid injection hole 15 is a through hole for injecting electrolyte into the inside of the battery case 10 after the sealing plate 14 is assembled to the exterior body 12. The liquid injection hole 15 is sealed by a sealing member 16 after the electrolytic solution is poured. The gas exhaust valve 17 is a thin walled portion configured to break when the pressure within the battery case 10 exceeds a predetermined value and discharge the gas within 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, respectively. The terminal extraction holes 18 and 19 penetrate the sealing plate 14 in the vertical direction Z.

The positive electrode 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 electrode 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). It is preferable that the positive electrode terminal 30 and the negative electrode terminal 40 are attached to the sealing plate 14. The positive electrode terminal 30 and the negative electrode terminal 40 are inserted through the terminal extraction holes 18 and 19, and a portion thereof is exposed on the surface of the sealing plate 14. The positive electrode terminal 30 and the negative electrode terminal 40 are connected to other secondary batteries and external equipment 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 of the electrode body 20 (see FIG. 5) via the positive current collector 50 and the positive electrode tab group 25 inside the battery case 10. There is. The positive electrode terminal 30 is preferably made of metal, and more preferably made of aluminum or an aluminum alloy, for example. The positive electrode terminal 30 is insulated from the sealing plate 14 by a gasket 92. It is preferable that the gasket 92 is made of resin.

The negative electrode terminal 40 is electrically connected to the negative electrode 24 of the electrode body 20 (see FIG. 5) via the negative electrode current collector member 60 and the negative electrode tab group 27 inside the battery case 10. 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 FIGS. 3 and 4, in the battery 100 of this embodiment, a plurality of (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 plurality of electrode bodies 20 are disposed inside the battery case 10 while being covered with an electrode body holder 29 made of a resin sheet. This prevents the electrode body 20 from coming into direct contact with the exterior body 12.

The material of the electrode body holder 29 is not particularly limited as long as it has a predetermined insulation property. Examples of such materials include synthetic resin materials such as polyolefin resins such as polypropylene (PP) and polyethylene (PE), and fluororesins such as perfluoroalkoxyalkanes and polytetrafluoroethylene (PTFE). As shown in FIG. 4, it is preferable that the upper end of the electrode body holder 29 substantially coincide with the lower end of a fixing member 70, which will be described later, in the vertical direction Z.

FIG. 5 is a schematic diagram showing the configuration of the electrode body 20. In addition, the code|symbol LD in FIG. 5 etc. has shown the longitudinal direction (namely, conveyance direction) of the electrode body 20 manufactured in a strip|belt shape. The symbol WD is a direction substantially orthogonal to the longitudinal direction LD, and indicates the direction of the winding axis 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 has a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 stacked in a state where they are insulated through two strip-shaped separators 26. This is a wound electrode body configured by winding the electrode body. However, the electrode body 20 is constructed by stacking a plurality of square-shaped (typically rectangular) positive electrodes and a plurality of square-shaped (typically rectangular) negative electrodes in an insulated state. A laminated electrode body may be used. As shown in FIG. 2, the end surface of the electrode body 20 (that is, the laminated surface where the positive electrode 22 and the negative electrode 24 are laminated, both ends in the winding axis direction WD in FIG. 5) is connected to the bottom wall 12a and the sealing plate 14. They are facing each other. 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 here. It is preferable that the electrode body 20 has a flat shape. 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 housed inside the battery case 10 so that the winding axis direction WD substantially coincides with the vertical direction Z. The pair of curved portions 20r are opposed to the pair of short side walls 12c of the exterior body 12. The pair of flat portions 20f face the long side walls 12b of the exterior body 12.

The positive electrode 22 is a band-shaped member, as shown in FIG. The positive electrode 22 includes a band-shaped positive electrode current collector 22c, and a positive electrode active material layer 22a and a positive electrode protective layer 22p fixed on at least one surface of the positive electrode current 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 current collector 22c. However, the positive electrode protective layer 22p is not essential and can be omitted in other embodiments.

For each member constituting the positive electrode 22, conventionally known materials that can be used in general batteries (for example, lithium ion secondary batteries) can be used without particular restriction. For example, the positive electrode current collector 22c is preferably made of a conductive metal such as aluminum, aluminum alloy, nickel, or stainless steel, and here, it is a metal foil, specifically an aluminum foil.

In the electrode body 20, as shown in FIG. 5, a plurality of positive electrode tabs 22t protrude outward (to the left in FIG. 5) from a root continuous to one end side in the winding axis direction WD. Note that the "root" is the boundary between the edge of the positive electrode 22 and the positive electrode tab 22t. The plurality of positive electrode tabs 22t are provided at predetermined intervals (intermittently) along the longitudinal direction LD. The number of positive electrode tabs 22t attached to one electrode body 20 may be approximately several tens or more, for example, about 40 to 60. The plurality of positive electrode tabs 22t are each connected to the positive electrode 22. The positive electrode tab 22t is a part of the positive electrode 22 here. The positive electrode tab 22t is a region where the positive electrode active material layer 22a is not formed. The positive electrode current collector 22c is exposed to at least a portion of the positive electrode tab 22t. However, the positive electrode tab 22t may be a separate member from the positive electrode 22. By providing a plurality of positive electrode tabs 22t, unevenness in resistance and potential within the positive electrode 22 can be reduced. The positive electrode tab 22t is an example of a first electrode tab.

The positive electrode tab 22t has a substantially rectangular shape here. The protruding length of the positive electrode tab 22t (the vertical length protruding from the root in the winding axis direction WD) may be longer than the electrode tabs disclosed in Patent Documents 1 to 3, for example, and is typically about 3 mm or more. is preferably about 4 to 10 mm, for example about 5 to 8 mm. The width (length in the longitudinal direction LD) of the positive electrode tab 22t is typically shorter than the protruding length of the positive electrode tab 22t, and is preferably approximately 15 mm or more, for example, 20 to 40 mm. The plurality of positive electrode tabs 22t may have mutually different sizes and shapes.

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

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 current collector 22c. The positive electrode protective layer 22p is provided at the boundary between the positive electrode current 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 current 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). There is. Providing the positive electrode protective layer 22p can prevent the positive electrode 22 from coming into direct contact with the negative electrode active material layer 24a and causing an internal short circuit in the battery 100 when the separator 26 is damaged.

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

The negative electrode 24 is a band-shaped member, as shown in FIG. The negative electrode 24 includes a strip-shaped negative electrode current collector 24c and a negative electrode active material layer 24a fixed on at least one surface of the negative electrode current collector 24c. From the viewpoint of battery performance, the negative electrode active material layer 24a is preferably formed on both sides of the negative electrode current collector 24c.

For each member constituting the negative electrode 24, conventionally known materials that can be used in general batteries (for example, lithium ion secondary batteries) can be used without particular restriction. For example, the negative electrode current collector 24c is preferably made of a conductive metal such as copper, copper alloy, nickel, or stainless steel, and here, it is a metal foil, specifically a copper foil.

In the electrode body 20, as shown in FIG. 5, a plurality of negative electrode tabs 24t protrude outward (to the left in FIG. 5) from a root continuous to one end side in the winding axis direction WD. The plurality of negative electrode tabs 24t are provided at predetermined intervals (intermittently) along the longitudinal direction LD. In the winding axis direction WD, the negative electrode tab 24t is provided at the end on the same side as the positive electrode tab 22t (left side in FIG. 5). The number of negative electrode tabs 24t attached to one electrode body 20 is approximately the same as the number of positive electrode tabs 22t, and may be approximately several tens or more, for example, about 40 to 60. The plurality of negative electrode tabs 24t are each connected to the negative electrode 24. The negative electrode tab 24t is a part of the negative electrode 24 here. The negative electrode tab 24t is a region where the negative electrode active material layer 24a is not formed here 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 a plurality of negative electrode tabs 24t, unevenness in resistance and potential within the negative electrode 24 can be reduced.

The negative electrode tab 24t has a substantially rectangular shape here. The protruding length of the negative electrode tab 24t (the vertical length protruding from the root in the winding axis direction WD) may be longer than the electrode tabs disclosed in Patent Documents 1 to 3, for example, and is typically about 3 mm or more. is preferably about 4 to 10 mm, for example about 5 to 8 mm. The width (length in the longitudinal direction LD) of the negative electrode tab 24t is typically shorter than the protruding length of the negative electrode tab 24t, and is preferably approximately 15 mm or more, for example, 20 to 40 mm. The plurality of negative electrode tabs 24t may have mutually different sizes and shapes.

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

As shown in FIG. 5, the negative electrode active material layer 24a is provided in a strip shape along the longitudinal direction LD of the negative electrode current collector 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. 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.

The separator 26 is a band-shaped member, as shown in FIG. The separator 26 is a member that insulates the positive electrode active material layer 22a of the positive electrode 22 and the negative electrode active material layer 24a of the negative electrode 24. Separator 26 constitutes the outer surface of electrode body 20 here. 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 may include a base material made of a porous resin sheet and a heat resistance layer (HRL) formed on at least one surface of the base material. The heat-resistant layer is a layer containing an inorganic filler. As the inorganic filler, for example, alumina, boehmite, aluminum hydroxide, titania, etc. can be used.

As the electrolyte, those used in general batteries (for example, lithium ion secondary batteries) can be used without particular limitation. An example is a non-aqueous electrolyte in which a supporting salt is dissolved in a non-aqueous solvent. Examples of nonaqueous solvents include carbonate solvents such as ethylene carbonate, dimethyl carbonate, and ethylmethyl carbonate. An example of a supporting salt is a fluorine-containing lithium salt such as LiPF ₆ . The electrolytic solution may contain additives as necessary. However, the electrolytic solution may be in a solid state (solid electrolyte) and may be 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 surface of the sealing plate 14. The positive electrode current collecting member 50 here consists of a 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). Thereby, it is possible to effectively prevent foreign matter from entering the electrode body 20, which will be described later. One end (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, that is, the plurality of stacked positive electrode tabs 22t. has been done. It is preferable that the positive electrode current collecting member 50 and the positive electrode tab group 25 are joined (for example, by ultrasonic welding).

The other (left side in FIG. 2) end in the long side direction Y of the positive electrode current collecting member 50 (specifically, the first region) is electrically connected to the lower end 30c of the positive electrode terminal 30. The positive electrode current collecting member 50 is preferably made of a metal with excellent conductivity, such as aluminum or an aluminum alloy. The positive electrode current collecting member 50 may be made of the same type of metal as the positive electrode tab 22t and/or the positive electrode 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 surface of the sealing plate 14. The negative electrode current collecting member 60 here consists of a 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 (left side in FIG. 2) end of the negative electrode current collecting member 60 (specifically, the first region) in the long side direction Y is electrically connected to the negative electrode tab group 27, that is, the plurality of stacked negative electrode tabs 24t. ing. It is preferable that the negative electrode current collecting member 60 and the negative electrode tab group 27 are joined (for example, by ultrasonic welding).

The other (right side in FIG. 2) end 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, and is made of copper or a copper alloy, for example. The negative electrode current collecting member 60 may be made of the same 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. It is preferable that an internal insulating member 94 made of resin is disposed between the positive electrode current collector member 50 and the sealing plate 14. It is preferable that an internal insulating member 94 made of resin is disposed between the negative electrode current collector member 60 and the sealing plate 14.

The plurality of fixing members 70 are for bundling the plurality of positive electrode tabs 22t and the plurality of negative electrode tabs 24t, respectively. As shown in FIG. 2, the plurality of fixing members 70 are attached to the positive electrode tab group 25 (the plurality of positive electrode tabs 22t) and the negative electrode tab group 27 (the plurality of negative electrode tabs 24t) of the electrode body 20, respectively. As shown in FIG. 4, a plurality of 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 tab 22t and for the negative electrode tab 24t). The number of fixing members 70 is four here. Note that although the plurality of positive electrode tabs 22t will be described in detail below as an example, the fixing member 70 can be similarly attached to the plurality of negative electrode tabs 24t. The technology disclosed herein is preferably applied to each of the plurality of positive electrode tabs 22t and the plurality of negative electrode tabs 24t.

As shown in FIG. 4, the plurality of positive electrode tabs 22t are integrally formed by bundling the portion connected to the positive electrode 22 (root portion) and the portion connected to the positive electrode current collecting member 50 with a fixing member 70. The state is maintained as follows. According to the inventor's studies, if the number of positive electrode tabs 22t is about several, it is easy to join (typically weld) to the positive electrode current collecting member 50 as is. However, in the battery 100 with increased capacity, when the number of positive electrode tabs 22t becomes several tens or more, the positive electrode tabs 22t tend to vary, making it difficult to stably ensure bonding with the positive electrode current collecting member 50. . Therefore, in the technique disclosed herein, the plurality of positive electrode tabs 22t are bundled using the fixing member 70 to form the positive electrode tab group 25. Thereby, the plurality of positive electrode tabs 22t and the positive electrode current collecting member 50 can be stably joined, and the joining performance (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 that can be bundled by the fixing member 70 may be a plurality (two or more). From the viewpoint of better exhibiting the effects of the technology disclosed herein, it is preferable that the number of positive electrode tabs 22t attached to one electrode body 20 is at least half of the total number. As shown in FIG. 4, all the positive electrode tabs 22t attached to one electrode body 20 are bundled by one fixing member 70 here. 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 metal with high electrical conductivity.

It is preferable that the fixing member 70 is a clamping member that clamps and holds the plurality of positive electrode tabs 22t. When the fixing member 70 is a clamping member, the plurality of positive electrode tabs 22t can be easily bent in a bundled state, and workability can be improved. Furthermore, welding is not required, and the generation of foreign matter such as metal powder can be suppressed when fixing the plurality of positive electrode tabs 22t 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 tab 22t. The width of the fixing member 70 in the long side direction Y is larger than the plurality of positive electrode tabs 22t, and may be, for example, 15 mm or more, and about 20 to 40 mm. The fixing member 70 is preferably one that can maintain a state parallel to the upper end of the electrode body 20 in the long side direction Y by stacking a plurality of positive electrode tabs 22t.

As an example of the fixing member 70, as shown in FIG. 2, a part having a YZ plane portion extending in the long side direction Y and the vertical direction Z, for example, a hollow cylindrical oval sleeve having a tunnel-like through hole in the vertical direction Z. can be mentioned. When using an oval sleeve as the fixing member 70, the plurality of positive electrode tabs 22t can be fixed to the oval sleeve by inserting the tips of the plurality of positive electrode tabs 22t into the through holes of the oval sleeve and then crimping them. Another example of the fixing member 70 is a plate-shaped clip member having a fixing portion on one or both sides of 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. Thereby, even if the electrode body 20 expands due to charging and discharging, conduction with, for example, the positive electrode tab 22t located at the outer edge of the electrode body 20 can be reliably maintained. It is preferable that portions of the plurality of positive electrode tabs 22t that are substantially perpendicular to the sealing plate 14 are bound together by a fixing member 70. Thereby, it is possible to effectively prevent foreign matter from entering the electrode body 20, which will be described later. In this specification, "substantially vertical" means approximately 92±15° (75 to 105°), preferably 92±10° (80 to 100°), for example 92±5° (85 to 95°). means.

It is preferable that the plurality of positive electrode tabs 22t are connected to the positive electrode current collecting member 50 in a state where the side closer to the positive electrode current collecting member 50 (the end e side) than the portion bundled by the fixing member 70 is bent. Thereby, the accommodation space for the electrode body 20 can be expanded, and the energy density of the battery 100 can be increased. 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 while being bundled by the fixing member 70. That is, it is preferable that the plurality of positive electrode tabs 22t have a curved portion 25b on the side closer to the positive electrode current collecting member 50 (the tip e side) than the portion bundled by the fixing member 70. Thereby, the plurality of positive electrode tabs 22t are easily combined into one, 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 bundled and bent base portions of the plurality of positive electrode tabs 22t are parallel to each other.

The insulating member 80 is a cover body that covers at least a portion of the end surface 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. Specifically, it is arranged between the positive electrode current collecting member 50 attached to the sealing plate 14 and the electrode body 20. The number of insulating members 80 is one here. However, as in a second embodiment described later, one battery 100 may include a plurality of insulating members 80.

As shown in FIG. 4, the insulating member 80 has a through hole 80h. The number of through holes 80h in the insulating member 80 is typically the number of electrode bodies 20 x 2 (for the positive electrode tab 22t and for the negative electrode tab 24t). The number of through holes 80h may be the same as the number of fixing members 70. The number of through holes 80h is four here. The plurality of positive electrode tabs 22t pass through the through hole 80h of the insulating member 80 in a state where they are bundled by the fixing member 70 and put together as the positive electrode tab group 25.

The insulating member 80 is disposed between the sealing plate 14 and the electrode body 20, and the plurality of positive electrode tabs 22t pass through the through holes 80h provided in the insulating member 80, thereby preventing battery performance such as voltage drop. It is possible to suppress conductive foreign matter that would lead to a decrease in conductivity from entering the inside of the electrode body 20 from the upper end surface of the electrode body 20. Furthermore, even if the electrode body 20 moves toward the sealing plate 14 due to external force such as vibration or impact when the battery 100 is used, the load on the positive electrode tab group 25 can be reduced. Further, it is possible to prevent the electrode body 20 from coming into contact with a member attached to the sealing plate 14 (for example, the positive electrode current collecting member 50) and being damaged.

The insulating member 80 preferably has a size that covers the entire upper end surface of the electrode body 20 when viewed from the XY plane. 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. Thereby, direct contact between the electrode body 20 and the electrode body holder 29 can be prevented. The insulating member 80 may be placed inside the electrode body holder 29 or may be placed 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 using a fixing means such as tape. The insulating member 80 is integrated with the electrode body holder 29 and may be a part of the electrode body holder 29.

It is preferable that the insulating member 80 is made of resin. The material of the insulating member 80 may be the same as that exemplified as the material of 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 made of a material and has a thickness such that, for example, the ends in the short side direction It is preferable. Therefore, as shown in FIG. 4 etc., it is preferable that the insulating member 80 is 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 plurality of positive electrode tabs 22t are stacked (short side direction X in FIG. 4), the width of the through hole 80h of the insulating member 80 is set as W1. , when the total thickness of the bundled portion of the plurality of 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) typically satisfies 1<(W1/T1). It is more preferable that the above formula (1) satisfies (W1/T1)<5.

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

The battery 100 is manufactured, for example, through the following steps: (Step 1) Electrode preparation step; (Step 2) Electrode body production step; (Step 3) Tab fixing step; (Step 4) Electrode body housing step; (Step 5) Bonding step (Step 6) A sealing step; typically, it can be manufactured by a method including in this order. The manufacturing method disclosed herein may further include other steps at any stage.

(Step 1) In the electrode preparation step, a strip-shaped positive electrode 22 having a plurality of positive electrode tabs 22t and a strip-shaped negative electrode 24 having a plurality of negative electrode tabs 24t are prepared. (Step 2) In the electrode body manufacturing process, first, a strip-shaped positive electrode 22 and a strip-shaped negative electrode 24 are laminated with a strip-shaped separator 26 in between, and are wound in the longitudinal direction around the winding axis WL to form a cylinder. Shape into shape. At this time, adjustment is made so that the plurality of positive electrode tabs 22t and the plurality of negative electrode tabs 24t protrude from the same edge and are stacked at different positions. Next, the electrode body (cylindrical body) wound into a cylindrical shape is press-molded into a flat shape, for example, to produce a flat electrode body 20 (see FIG. 5).

(Step 3) In the tab fixing step, the plurality of positive electrode tabs 22t and the plurality of negative electrode tabs 24t are each bundled with the fixing member 70 to fix the collected state. Note that this step is preferably performed at the same time as molding the electrode body 20. The fixing position of the fixing member 70 is preferably as close to the electrode body 20 as possible from the viewpoint of expanding the accommodation space for the electrode body 20. The plurality of positive electrode tabs 22t are bundled together by the fixing member 70 to be integrated as a positive electrode tab group 25. Similarly, the plurality of negative electrode tabs 24t are bundled together by the fixing member 70 to be integrated as a negative electrode tab group 27.

(Step 4) In the electrode body housing step, after inserting the electrode body 20 into the electrode body holder 29, the electrode body 20 wrapped in the electrode body holder 29 is placed so that the positive electrode tab group 25 and the negative electrode tab group 27 are on the upper side. It is housed in the exterior body 12 so that it faces. 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. Thereby, the insulating member 80 is arranged so as to cover the upper end surface of the electrode body 20.

(Step 5) In the bonding process, the tip sides of the positive electrode tab group 25 and the tip sides 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 with respect to the fixing member 70. Further, the positive electrode terminal 30, the negative electrode terminal 40, the positive electrode current collecting member 50, and the negative electrode current collecting member 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 (for example, welded) to the positive current collecting member 50 attached to the sealing plate 14. Further, the tip of the negative electrode tab group 27 is joined to the negative electrode current collector member 60 attached to the sealing plate 14 . As a result, a joint (for example, welded joint) J is formed between the positive electrode current collecting member 50 and the positive electrode tab group 25, and a joint (for example, welded joint) J between the negative electrode current collector 60 and the negative electrode tab group 27 is formed. Form.

(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 substantially U-shape, respectively, and then inserted into the opening 12h of the exterior body 12. The sealing plate 14 is fitted, and the peripheral edge of the opening 12h of the exterior body 12 and the sealing plate 14 are joined (for example, by welding). Thereby, the battery case 10 is hermetically sealed. The battery 100 can be manufactured as described above.

<Second embodiment>
FIG. 7 is a diagram 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 include 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 together by 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 by a fixing member 70, and pass through the through hole 80h of the second insulating member 80b. This improves assembly efficiency and allows the battery 200 to be manufactured efficiently. Further, it is possible to effectively suppress foreign matter from entering the electrode body 20.

For example, the battery 200 can be manufactured by a manufacturing method that includes a (step 4A) bonding process and (step 5A) an electrode body housing process in this order instead of steps 4 and 5 of the first embodiment.

(Step 4A) In the bonding process, as shown in FIG. 8, a plurality of positive electrode tabs 22t and negative electrode tabs 24t are inserted into the through holes 80h of the first insulating member 80a and the second insulating member 80b, respectively. Thereby, 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 collecting member 50, and the negative electrode current collecting member 60 are attached to the sealing plate 14. Next, the tips 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 member 50 attached to the sealing plate 14, respectively. Further, the tips of the plurality of negative electrode tabs 24t of the first electrode body 20a and the second electrode body 20b are joined (for example, welded) to the negative electrode current collector member 60 attached to the sealing plate 14, respectively. This forms a joint (for example, a welded joint) J between the positive electrode current collecting member 50 and the plurality of positive electrode tabs 22t, and a joint (for example, welded joint) between the negative electrode current collector 60 and the plurality of negative electrode tabs 24t. Form J.

(Step 5A) In the electrode body housing step, the tip e side of the positive electrode tab group 25 and the tip e side of the negative electrode tab group 27 protruding from the upper end of the fixing member 70 are respectively shaped into a substantially L-shape with respect to the fixing member 70. fold it. Next, after inserting the electrode body 20 into the electrode body holder 29, the electrode body 20 wrapped in the electrode body holder 29 is housed in the exterior body 12.

<Uses of batteries>
Although the battery 100 can be used for various purposes, it is suitable for applications that require high capacity, applications where external forces such as vibrations and shocks may be applied during use, such as moving objects (typically vehicles such as passenger cars and trucks). It can be suitably used as a power source (driving power source) for a motor mounted on a motor. Although the type of vehicle is not particularly limited, 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 content disclosed in this specification and the common general knowledge in the field. The technology described in the claims includes various modifications and changes to the embodiments exemplified above. For example, it is also possible to replace a part of the embodiment described above with other modifications, and it is also possible to add other modifications to the embodiment described above. Also, if the technical feature is not described as essential, it can be deleted as appropriate.

As mentioned above, specific aspects of the technology disclosed herein include those described in the following sections.
Item 1: One or more electrode bodies including a first electrode and a second electrode, a battery case accommodating the electrode body, and a battery case connected to the first electrode and disposed at an end of the electrode body. a plurality of first electrode tabs, a current collecting member connected to the plurality of first electrode tabs, and a plurality of first electrode tabs connected to a portion connected to the first electrode and the current collecting member; and one or more insulating members arranged between the first surface of the battery case and the electrode body, the insulating member having a through hole. A battery, wherein the plurality of first electrode tabs pass through the through holes of the insulating member.
Item 2: In the direction in which the plurality of first electrode tabs are stacked, the width of the through hole of the insulating member is W1, and the total thickness of the bundled portion of the plurality of first electrode tabs is T1. The battery according to item 1, wherein the W1 and the T1 satisfy the following formula: (W1/T1)<10;
Item 3: The electrode body includes a first electrode body and a second electrode body, and the insulating member includes a first insulating member and a second insulating member, and is connected to the first electrode body. The plurality of first electrode tabs connected to the second electrode body pass through the through hole of the first insulating member, and the plurality of first electrode tabs connected to the second electrode body pass through the through hole of the second insulating member. Item 3. The battery according to item 1 or 2, which has a hole passing through it.
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: In the 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 are different from each other. , the battery according to item 4, which satisfies the following formula: (W1/W2)<5;
Item 6: The plurality of first electrode tabs described in any one of Items 1 to 5, wherein portions substantially perpendicular to the first surface of the battery case are bound by the fixing member. battery.
Item 7: Any of Items 1 to 6, wherein the plurality of first electrode tabs are connected to the current collecting member in a state where the side closer to the current collecting member than the part bundled by the fixing member is bent. or the battery described in one of the above.
Item 8: The current collecting member has a first region disposed along the first surface of the battery case, and the plurality of first electrode tabs are stacked and connected to the first region. 8. The battery according to any one of Items 1 to 7.

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 (8)

one or more electrode bodies including a first electrode and a second electrode;
a battery case that houses the electrode body;
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 that bundles the plurality of 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 plurality of first electrode tabs penetrate the through hole of the insulating member,
battery. In the direction in which the plurality of first electrode tabs are stacked, the width of the through hole of the insulating member is W1, and the total thickness of the bundled portion of the plurality of first electrode tabs is T1, The W1 and the T1 satisfy the following formula: (W1/T1)<10;
The battery according to claim 1. 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 penetrate the through hole of the first insulating member,
The plurality of first electrode tabs connected to the second electrode body penetrate through the through hole of the second insulating member.
The battery according to claim 1 or 2. at least a portion of the fixing member is disposed inside the through hole;
The battery according to claim 1 or 2. In the 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 are as follows. Formula: (W1/W2)<5;
The battery according to claim 4. The plurality of first electrode tabs have portions substantially perpendicular to the first surface of the battery case bound together by the fixing member.
The battery according to claim 1 or 2. The plurality of first electrode tabs are connected to the current collecting member in a state where the side closer to the current collecting member than the portion bundled by the fixing member is bent.
The battery according to claim 1 or 2. The current collecting member has a first region disposed along the first surface of the battery case,
the plurality of first electrode tabs are stacked and connected to the first region;
The battery according to claim 1 or 2.

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