Electricity storage device and method for manufacturing electricity storage device

Abstract

The invention relates to an electricity storage device and a method for manufacturing the electricity storage device. This electricity storage device is provided with an electrode body, a case main body, a lid, a terminal, an insulating member, a current collector, and an insulating film. The electrode body has a tab. The insulating film is disposed within the case body so as to cover the electrode body. The insulating film is configured from a resin film that insulates the case body from the electrode body. The insulating film is bonded to at least one of the cap, the insulating member attached to the cap, and the current collector.

Description

Technical Field

[0001] The present invention relates to an electricity storage device and a method for manufacturing the electricity storage device. Background Art

[0002] Japanese Patent Gazette No. 2022-188665 discloses a battery having an electrode body and a battery case for accommodating a plurality of electrode bodies. The electrode bodies each have a pair of flat outer surfaces. An electrode tab group of a positive electrode and a negative electrode is provided on the electrode body. An electrode collector is mounted on the electrode tab group. A fixing component having a substrate and an adhesive layer is arranged from a pair of flat outer surfaces of the electrode body to the electrode collector. In a battery of this structure, it is believed that damage to the electrode tab group can be prevented.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2022-188665 Summary of the invention

[0004] The present inventors have considered proposing a new structure for reducing damage to an electrode tab.

[0005] The power storage device disclosed herein comprises: an electrode body having a tab; a shell body having an opening and accommodating the electrode body; a cover that blocks the opening; a terminal mounted on the cover; an insulating component sandwiched between the cover and the terminal; a collector connected to the terminal and the tab of the electrode body; and an insulating film composed of a resin film, which is arranged in the shell body in a manner covering the electrode body and insulates the shell body from the electrode body. The insulating film is bonded to at least one of the cover, the insulating component mounted on the cover, and the collector. In the above power storage device, damage to the tab can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a perspective view showing the power storage device 100 .

[0007] Figure 2 It is along Figure 1 Schematic cross-sectional view of line II-II in FIG.

[0008] Figure 3 It is a perspective view schematically showing the electrode body 40 .

[0009] Figure 4 It is a perspective view of the electrode body 40 to which the second current collectors 72 and 77 are connected.

[0010] Figure 5 It is a perspective view of the electrode body 40 to which the cover 54 is connected.

[0011] Figure 6 is a top view of the insulating film 98 .

[0012] Figure 7It is a perspective view of the electrode body 40 covered with the insulating film 98 .

[0013] Figure 8 It is a perspective view of the electrode body 40 covered with the insulating film 98 .

[0014] Fig. 9 It is an enlarged view of the cover 54 to which the electrode body 40 is connected. DETAILED DESCRIPTION

[0015] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the accompanying drawings. The embodiments described here are of course not intended to specifically limit the present invention. The drawings are schematically depicted and may not reflect the actual objects. In addition, the same figure marks are appropriately marked for components / parts that play the same role, and repeated descriptions are appropriately omitted. In the following description, the figure marks L, R, F, Rr, U, and D in the drawings represent left, right, front, back, top, and bottom, and the figure marks X, Y, and Z in the drawings represent the short side direction, long side direction, and height direction of the power storage device, respectively. However, these are just directions for the convenience of explanation and do not constitute any limitation on the setting method of the power storage device.

[0016] <Electrical Storage Device 100>

[0017] Figure 1 It is a perspective view showing the power storage device 100 . Figure 2 It is along Figure 1 Schematic cross-sectional view of line II-II in . The energy storage device 100 includes an electrode body 40, a shell body 52, a cover 54, terminals 60, 65, collectors 70, 75, insulating parts 90, 92, 94, and an insulating film 98. In this specification, the term "energy storage device" refers to a device that can extract electrical energy. The energy storage device includes a secondary battery that can be repeatedly charged and discharged by the movement of charge carriers through an electrolyte between a pair of electrodes (positive and negative electrodes), such as a lithium-ion secondary battery. Below, taking a lithium-ion secondary battery as an example, the energy storage device 100 is described together with the manufacturing method of the energy storage device 100.

[0018] <Method of Manufacturing Electricity Storage Device 100>

[0019] The method for manufacturing the power storage device 100 includes preparing the case body 52 , preparing the electrode body 40 , preparing the insulating film 98 , restraining the electrode body 40 with the insulating film 98 , and housing the electrode body 40 in the case body 52 .

[0020] <Step of Preparing the Case Body 52>

[0021] In the step of preparing the case body 52, the case body 52 that accommodates the electrode body 40 is prepared. In this embodiment, a square case body 52 is prepared as the case body 52. Figure 1 As shown, the housing body 52 has: a bottom wall 52a having a substantially rectangular plane; a pair of first side walls 52b extending upward in the height direction Z from the long sides of the bottom wall 52a; and a pair of second side walls 52c extending upward in the height direction Z from the short sides of the bottom wall 52a. The housing body 52 has a substantially rectangular opening 52h at the top (see Figure 2 ). In other words, the upper opening of the housing body 52 is substantially rectangular.

[0022] <Step of Preparing Electrode Body 40>

[0023] In the step of preparing the electrode body 40, the current collectors 70 and 75 (see Figure 2 ) is mounted on the electrode body 40 of the cover 54. In the step of preparing the electrode body 40, the electrode body 40 can be prepared as follows. The cover 54, the electrode body 40, and the collectors 70 and 75 (positive electrode collector 70 and negative electrode collector 75) are prepared separately. In this embodiment, as Figure 2 As shown, the positive electrode current collector 70 includes a positive electrode first current collector 71 and a positive electrode second current collector 72. The negative electrode current collector 75 includes a negative electrode first current collector 76 and a negative electrode second current collector 77. Hereinafter, the positive electrode first current collector 71 and the negative electrode first current collector 76 are also referred to as "first current collectors 71, 76", and the positive electrode second current collector 72 and the negative electrode second current collector 77 are also referred to as "second current collectors 72, 77". The positive electrode first current collector 71 and the negative electrode first current collector 76 are mounted on the cover 54. The positive electrode second current collector 72 and the negative electrode second current collector 77 are mounted on the electrode body 40. Hereinafter, the cover 54, the electrode body 40, and the current collectors 70, 75 are described in sequence. In addition, the current collectors 70 and 75 do not need to be divided into the first current collectors 71 and 76 and the second current collectors 72 and 77 , and may be integrated into one current collector.

[0024] 〈Cover 54〉

[0025] The cover 54 is a component that blocks the opening 52h at the top of the shell body 52. ​​The shell body 52 and the cover 54 are appropriately referred to as the shell 50. The cover 54 has a shape corresponding to the opening 52h. In this embodiment, the cover 54 is a roughly rectangular plate-shaped component. The cover 54 is provided with an injection hole 55 and a gas exhaust valve 57. The injection hole 55 is a through hole provided for injecting electrolyte (not shown) into the interior of the shell 50. When the injection of the electrolyte is completed, the injection hole 55 is sealed by the sealing component 56. The gas exhaust valve 57 is a thin-walled portion designed to break (open) when a large amount of gas is generated in the shell 50 to exhaust the gas. Terminal insertion holes 58, 59 (refer to Figure 2 The terminal insertion holes 58 and 59 are respectively formed at the end portions in the width direction Y of the cover 54 .

[0026] Terminals (positive electrode terminal 60 and negative electrode terminal 65) are attached to the cover 54 via insulating members 90, 92, and 94. The positive electrode terminal 60 and the negative electrode terminal 65 are attached to the ends of the cover 54 in the width direction Y of the power storage device 100, respectively. The positive electrode terminal 60 is connected to a plate-like positive electrode external conductive member 62 outside the case 50. The negative electrode terminal 65 is connected to a plate-like negative electrode external conductive member 67 outside the case 50. The positive electrode external conductive member 62 and the negative electrode external conductive member 67 are connected to other power storage devices and external equipment via external connecting members (bus bars, etc.).

[0027] <First current collectors 71, 76>

[0028] The first current collectors 71 and 76 are plate-shaped conductive members. Figure 2 As shown, the first positive electrode current collector 71 and the first negative electrode current collector 76 extend along the inner side surface of the cover 54, respectively. The first positive electrode current collector 71 and the first negative electrode current collector 76 are mounted on the inner side surface of the cover 54. The lower end 60c of the positive terminal 60 is connected to the first positive electrode current collector 71. The lower end 65c of the negative terminal 65 is connected to the first negative electrode current collector 76.

[0029] <Insulating components 90, 92, 94>

[0030] The insulating members 90, 92, 94 include a gasket 90, an external insulating member 92, and an internal insulating member 94. The gasket 90 is attached to the terminal insertion holes 58, 59 of the cover 54. The gasket 90 is interposed between the cover 54 and the terminals 60, 65 in the terminal insertion holes 58, 59 to prevent conduction between the cover 54 and the terminals 60, 65. The external insulating member 92 is arranged on the outer side surface of the cover 54. The external insulating member 92 is interposed between the cover 54 and the positive electrode external conductive member 62 and the negative electrode external conductive member 67 on the outer side surface of the cover 54 to prevent conduction between the cover 54 and the positive electrode external conductive member 62 and the negative electrode external conductive member 67. The internal insulating member 94 is arranged on the inner side surface of the cover 54. The internal insulating member 94 is interposed between the cover 54 and the first current collectors 71, 76 on the inner side surface of the cover 54 to prevent conduction between the cover 54 and the first current collectors 71, 76.

[0031] The internal insulating component 94 includes a plate-shaped base 94a mounted on the inner side of the cover 54. The internal insulating component 94 includes a protrusion 94b protruding from the base 94a toward the electrode body 40. The protrusion 94b limits the movement of the electrode body 40 in the up and down directions to prevent the electrode body 40 from directly contacting the cover 54. The material of the insulating component has a predetermined insulation property and can be selected in consideration of electrolyte resistance and heat resistance. As the insulating component, synthetic resin materials such as polyolefin resins, polyamide resins, PPS resins (polyphenylene sulfide), and fluorine resins can be used.

[0032] <Electrode body 40>

[0033] Figure 3 is a perspective view schematically showing the electrode body 40. Figure 3 As shown, the electrode body 40 is an electrode body formed by winding a strip-shaped positive electrode 10 and a strip-shaped negative electrode 20 via a strip-shaped separator 30. The electrode body 40 has tabs (a positive electrode tab group 42 and a negative electrode tab group 44 in this embodiment). The electrode body 40 is a so-called wound electrode body. For example, the electrode body 40 is prepared by overlapping the positive electrode 10 and the negative electrode 20 in the same direction via a separator 30 and winding them around a winding axis WL. The outer peripheral surface of the wound electrode body 40 is covered by the separator 30. The winding axis WL is set to the width direction of the positive electrode 10, the negative electrode 20 and the separator 30. In this embodiment, the electrode body 40 is stamped and formed into a flat shape after winding. A flat portion 40f with a flat outer surface is formed on the electrode body 40 (see Figure 4 ). The electrode body 40 is not limited to this embodiment. The electrode body 40 may be a so-called laminated electrode body in which a rectangular positive electrode and a negative electrode are stacked with a separator interposed therebetween.

[0034] 〈Positive Electrode 10〉

[0035] The positive electrode 10 is a long strip-shaped component. The positive electrode 10 includes a positive electrode core 12 as a foil-shaped metal component and a positive electrode active material layer 14 formed on the surface of the positive electrode core 12. From the perspective of battery performance, it is preferred that the positive electrode active material layer 14 is formed on both sides of the positive electrode core 12. A positive electrode 10 is provided with an outer side (Y direction) at one side edge portion. Figure 3 The positive electrode tab 12t protrudes (on the left side in the figure). A plurality of positive electrode tabs 12t are provided at predetermined intervals in the longitudinal direction of the positive electrode 10. The positive electrode tab 12t is an area where the positive electrode core 12 is exposed and the positive electrode active material layer 14 and the protective layer 16 are not formed. When the electrode body 40 is wound, the positive electrode tabs 12t are stacked to form a positive electrode tab group 42 connected to each other. As the positive electrode core 12, a metal material having a predetermined conductivity is preferably used. The positive electrode core 12 is preferably composed of, for example, aluminum, an aluminum alloy, or the like.

[0036] The positive electrode active material layer 14 is a layer containing a positive electrode active material. The positive electrode active material is a material that can reversibly absorb / release charge carriers in relation to the negative electrode active material described later. The positive electrode active material is not particularly limited. As the positive electrode active material, for example, a lithium transition metal composite oxide is preferably used.

[0037] The positive electrode active material layer 14 may also include additives other than the positive electrode active material. The positive electrode active material layer 14 may include a binder. As the binder, a resin binder can be preferably used. As the resin binder, for example, polyvinylidene fluoride (PVDF) can be preferably used. Preferably, the positive electrode active material layer 14 includes a conductive material. As the conductive material, a carbon material such as acetylene black (AB) can be preferably used.

[0038] A protective layer 16 may be provided at one side edge of the positive electrode 10 as needed. The protective layer 16 is a layer having lower electrical conductivity than the positive electrode active material layer 14. The protective layer 16 is provided on the positive electrode core 12 at a position facing the negative electrode active material layer 24 via the separator 30. The configuration of the protective layer 16 is not particularly limited, and may be, for example, a layer coated with a resin, or a layer containing inorganic particles or a binder.

[0039] 〈Negative Electrode 20〉

[0040] The negative electrode 20 is a long strip-shaped component. The negative electrode 20 includes a negative electrode core 22 as a foil-shaped metal component and a negative electrode active material layer 24 formed on the surface of the negative electrode core 22. From the perspective of battery performance, it is preferred that the negative electrode active material layer 24 is formed on both sides of the negative electrode core 22. A side edge portion of the negative electrode 20 is provided with an outer side ( Figure 3The negative electrode tab 22t protrudes toward the opposite side of the positive electrode tab 12t described above. A plurality of negative electrode tabs 22t are provided at predetermined intervals in the longitudinal direction of the negative electrode 20. The negative electrode tab 22t is an area where the negative electrode core 22 is exposed and the negative electrode active material layer 24 is not formed. In a state where the electrode body 40 is wound, the negative electrode tabs 22t are stacked to form a negative electrode tab group 44 connected to each other. As the negative electrode core 22, a metal material having a predetermined conductivity is preferably used. The negative electrode core 22 is preferably composed of, for example, copper, a copper alloy, or the like.

[0041] The negative electrode active material layer 24 is a layer containing a negative electrode active material. The negative electrode active material is a material that can reversibly absorb / release charge carriers in relation to the positive electrode active material. The negative electrode active material is not particularly limited. As the negative electrode active material, for example, carbon materials, silicon-based materials, and mixed oxides thereof are preferably used. As carbon materials, for example, graphite, hard carbon, soft carbon, amorphous carbon, etc. can be used. As silicon-based materials, silicon, silicon oxide (silica), etc. can be cited.

[0042] The negative electrode active material layer 24 may also contain additives other than the negative electrode active material. The negative electrode active material layer 24 may contain a binder as an additive. As the binder, a resin binder is preferably used. As the resin binder, for example, styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyacrylic acid (PAA), etc. may be included. Preferably, the negative electrode active material layer 24 contains a conductive material. As the conductive material, carbon materials such as acetylene black (AB) and carbon nanotubes can be preferably used.

[0043] <Diaphragm 30>

[0044] The separator 30 is a long strip-shaped member that prevents the positive electrode 10 and the negative electrode 20 from contacting each other and has the function of allowing charge carriers to pass through. The width of the separator 30 can be set to a size that can cover the positive electrode active material layer 14 of the positive electrode 10 and the negative electrode active material layer 24 of the negative electrode 20. As the separator 30, it is preferred to use a porous film made of a resin having a plurality of tiny holes through which charge carriers can pass. As the separator 30, for example, a porous sheet (film) composed of a resin such as polyolefins such as polyethylene (PE) and polypropylene (PP), polyamide, etc. can be cited. The porous sheet can be a single-layer structure or a stacked structure of two or more layers.

[0045] A heat-resistant layer may be formed on the resin sheet constituting the separator 30. The heat-resistant layer is a layer having excellent heat resistance. The heat-resistant layer preferably contains ceramic particles and a binder. As the ceramic particles, for example, alumina or the like can be used.

[0046] The separator 30 may include an adhesive layer. The adhesive layer is a layer having excellent adhesion to the electrode plates (positive electrode 10, negative electrode 20). The adhesive layer can be formed on the surface of the resin sheet constituting the separator 30. The positive electrode 10 and the separator 30 are easily bonded through the adhesive layer. The negative electrode 20 and the separator 30 are easily bonded through the adhesive layer. As the adhesive layer, known materials can be used. A resin material can be used as the adhesive layer. The adhesive layer can contain, for example, an adhesive such as polyvinylidene fluoride. The adhesive layer can contain ceramic particles. As the adhesive layer, for example, an adhesive layer that generates an adhesive force by pressure, heat, etc. can be used.

[0047] Figure 4 It is a perspective view of the electrode body 40 to which the second current collectors 72 and 77 are connected. Figure 5 It is a perspective view of the electrode body 40 to which the cover 54 is connected.

[0048] <Second collector 72, 77>

[0049] The second current collectors 72 and 77 are plate-shaped conductive members. Figure 4 As shown, the positive electrode second current collector 72 and the negative electrode second current collector 77 are respectively connected to the tabs (positive electrode tab group 42, negative electrode tab group 44) of the electrode body 40. In other words, the electrode body 40 is connected to the collectors (positive electrode second current collector 72 and negative electrode second current collector 77) via the tabs. The tabs and the second current collectors 72 and 77 can be joined by laser welding, for example.

[0050] like Figure 5 As shown, the positive electrode tab group 42 and the negative electrode tab group 44 are bent in a state where the second current collectors 72 and 77 are connected respectively. The bent second current collectors 72 and 77 are connected to the first current collectors 71 and 76 arranged on the inner side of the cover 54. Thus, the electrode body 40 is mounted on the cover 54. In this embodiment, three electrode bodies 40 are mounted on the cover 54. The electrode body 40 is mounted on the cover 54 in a state of overlapping along the thickness direction X and aligning in the width direction Y and the height direction Z. In addition, the number of electrode bodies 40 mounted on the cover 54 is not particularly limited, and can be one or more.

[0051] <Step of Preparing Insulating Film 98>

[0052] In the step of preparing the insulating film 98, the insulating film 98 made of a resin film is prepared (see Figure 1 as well as Figure 6 ). The insulating film 98 is a thin sheet-shaped insulating member arranged in the case body 52 in a manner covering the electrode body 40. As the insulating film 98, for example, a resin material such as polypropylene (PP) or polyethylene (PE) can be used. Here, the insulating film 98 corresponding to the shape of the electrode body 40 can be prepared.

[0053] Figure 6 is a top view of the insulating film 98. Figure 6 , a development view of the insulating film 98 before covering the electrode body 40 is shown. Figure 6 As shown in FIG. 1 , the insulating film 98 includes a bottom surface 98 a , a wide surface 98 b , and a side surface 98 c . The dimensions of the bottom surface 98 a , the wide surface 98 b , and the side surface 98 c can be set according to the dimensions of the electrode body 40 .

[0054] The bottom portion 98a is substantially rectangular. The bottom portion 98a has a thickness ( Figure 5 The X-dimension of Figure 5 The dimension of the short side of the bottom portion 98a is set to be approximately the same as the thickness of the electrode body 40. The dimension of the bottom portion 98a can be set in such a way that the difference between the dimension of the short side of the bottom portion 98a and the thickness of the electrode body 40 is 1 mm or less (for example, 0.5 mm or less). In this specification, "the thickness of the electrode body 40" refers to the total thickness of the electrode body 40. The "thickness of the electrode body 40" is the total thickness of the multiple electrode bodies 40 when multiple electrode bodies 40 are overlapped along the thickness direction. In this embodiment, the "thickness of the electrode body 40" is the total thickness of the three overlapping electrode bodies 40.

[0055] In addition, the size of the long side of the bottom portion 98a is set to be substantially the same as the width of the electrode body 40 including the mounted current collectors 70 and 75. In this embodiment, the width of the electrode body 40 corresponds to the size from the outer side of the second current collector 72 to the outer side of the second current collector 77. The size of the bottom portion 98a can be set so that the difference between the size of the long side of the bottom portion 98a and the width of the electrode body 40 is 1 mm or less (for example, 0.5 mm or less).

[0056] The wide surface 98b includes a first wide surface 98b1 and a second wide surface 98b2. The first wide surface 98b1 and the second wide surface 98b2 are each substantially rectangular. The first wide surface 98b1 and the second wide surface 98b2 have a width and a height ( Figure 5 The first wide surface 98b1 and the second wide surface 98b2 are respectively provided from the bottom surface 98a to the width of the electrode body 40 ( Figure 5 The Y-direction dimension) of the corresponding edge extends.

[0057] A pair of side portions 98c are provided in the left-right direction Y. The pair of side portions 98c extend from the bottom portion 98a and the wide width portion 98b, respectively. The pair of side portions 98c include a first side portion 98c1, a second side portion 98c2, and a third side portion 98c3, respectively. The first side portion 98c1 extends from the first wide width portion 98b1. The second side portion 98c2 extends from the second wide width portion 98b2. The third side portion 98c3 extends from the bottom portion 98a. In this embodiment, the first side portion 98c1, the second side portion 98c2, and the third side portion 98c3 are symmetrical in the left-right direction Y except for a portion 98d1 that is cut off, which will be described later.

[0058] A cutout 98d is formed between the first side surface portion 98c1 and the third side surface portion 98c3, and between the second side surface portion 98c2 and the third side surface portion 98c3. In this embodiment, the cutout 98d is formed from the end of the side surface portion 98c in the left-right direction Y to the boundary between the side surface portion 98c and the bottom surface portion 98a and the wide surface portion 98b. The cutout 98d is substantially in the shape of a right triangle. A partially cutout portion 98d1 may be provided on the side surface portion 98c to indicate the direction of the insulating film 98.

[0059] The shape of the cutout 98d is not particularly limited, and may be, for example, a substantially rectangular shape or a shape formed by a curve such as an arc. In addition, the cutout 98d may not be formed in the insulating film 98, but a slit may be formed in the side surface 98c along the extension line of the boundary between the bottom surface 98a and the wide surface 98b.

[0060] A joint portion 98e is set on the side portion 98c to be joined with the collectors 70 and 75 in a subsequent process. In this embodiment, the joint portion 98e is set at the first side portion 98c1 and the second side portion 98c2. The joint portion 98e is set at a position where the first side portion 98c1 overlaps with the second side portion 98c2 when the insulating film 98 is assembled. In this embodiment, the joint portion 98e is set at a position in contact with the collector 70 of the electrode body 40 installed in the middle of the three electrode bodies 40. The joint portion 98e can be subjected to a treatment for improving the bonding property when joining with the collectors 70 and 75 in a subsequent process. In addition, the position of the joint portion 98e is not particularly limited.

[0061] The insulating film 98 is provided with boundaries B1 to B4 of the bottom portion 98a, the wide portion 98b, and the side portion 98c. The insulating film 98 is bent along the boundaries B1 to B4 in a subsequent process to cover the electrode body 40. The boundaries B1 to B4 are set according to the size (e.g., thickness, width, height) of the electrode body 40. The boundary B1 is set between the bottom portion 98a and the wide portion 98b. The boundary B2 is set between the first wide portion 98b1 and the first side portion 98c1. The boundary B3 is set between the second wide portion 98b2 and the second side portion 98c2. The boundary B4 is set between the bottom portion 98a and the third side portion 98c3.

[0062] As described above, the dimensions of the long side and the short side of the bottom portion 98a are respectively set to the same extent as the thickness and width of the electrode body 40. From the perspective of dimensional error of the components, the dimensions of the long side and the short side of the bottom portion 98a can be respectively set to a dimensional difference of 1 mm or less (e.g., 0.5 mm or less) relative to the thickness and width of the electrode body 40. The boundaries B1 to B4 are provided at positions where the electrode body 40 and the insulating film 98 are easily constrained on the side circumference of the electrode body 40 when the electrode body 40 is covered with the insulating film 98.

[0063] The insulating film 98 may be subjected to a process for improving workability during folding, such as preliminary folding along the boundaries B1 to B4 and providing grooves to a degree that the insulating film 98 is not broken along the boundaries B1 to B4.

[0064] <Step of restraining the electrode body 40 with the insulating film 98>

[0065] In the process of constraining the electrode body 40 with the insulating film 98 (hereinafter, also referred to as the "constraining process"), the electrode body 40 is constrained by covering it with the insulating film 98. In addition, the process of constraining the electrode body 40 with the insulating film 98 includes bonding the insulating film 98 to at least one of the cover 54, the insulating member 94 attached to the cover 54, and the collectors 70 and 75. In this embodiment, a part of the insulating film 98 is bonded to a part of the collector 70 in the constraining process.

[0066] Figure 7 FIG. 4 is a perspective view of the electrode body 40 covered with the insulating film 98. Figure 7 , a state in which a part of the insulating film 98 is broken and the electrode body 40 is exposed is shown. Figure 7 As shown, in the step of constraining, the insulating film 98 is folded along the electrode body 40 to cover the electrode body 40 with the insulating film. The insulating film 98 is folded along the boundaries B1 to B4.

[0067] First, the bottom surface 98a of the insulating film 98 is aligned with the lower surface of the electrode body 40. The insulating film 98 is bent along the boundary B1. Thus, the wide surface 98b of the insulating film 98 faces the flat portion 40f of the electrode body 40. The insulating film 98 is bent along the boundary B2. Thus, the first side surface 98c1 of the insulating film 98 is aligned with the side surface of the electrode body 40 and the second current collectors 72 and 77 (see Figure 5 ) are opposite. The insulating film 98 is bent along the boundary B3. Thus, the second side portion 98c2 of the insulating film 98 overlaps from the outside relative to a portion of the first side portion 98c1. The insulating film 98 is bent along the boundary B4. Thus, the third side portion 98c3 of the insulating film 98 overlaps from the outside relative to a portion of the first side portion 98c1 and the second side portion 98c2. Thus, the electrode body 40 is covered by the insulating film 98. At this time, in order to firmly constrain the electrode body 40, the bending position of the insulating film 98 can be appropriately adjusted. In addition, the bending order of the insulating film 98 is not particularly limited. For example, the first wide surface portion 98b1 of the insulating film 98 can be aligned with the flat portion 40f of the electrode body 40 first, or the third side portion 98c3 of the insulating film 98 can be located on the inside relative to the first side portion 98c1 and a portion of the second side portion 98c2.

[0068] Next, in a state where the electrode body 40 is covered with the insulating film 98, a part of the insulating film 98 is joined to the current collectors 70 and 75. At this time, a part of the insulating film 98 and the current collectors 70 and 75 may be joined while applying a restraining pressure to the electrode body 40 by the insulating film 98. The joining method is not particularly limited.

[0069] In this embodiment, a portion of the insulating film 98 is heated to fuse the portion of the insulating film 98 to a portion of the current collectors 70 and 75. Figure 7 As shown, a joint portion 98e is set at the position where the first side portion 98c1 and the second side portion 98c2 of the insulating film 98 overlap. The joint portion 98e of the insulating film 98 is heated. The heating method is not particularly limited. For example, the insulating film 98 and the collectors 70 and 75 can be fused by pressing a welding pin heated to above the melting point of the insulating film 98 on the joint portion 98e. The heating conditions at this time are set to the extent that the insulating film 98 melts and fuses with the collectors 70 and 75 at the joint portion 98e where the heated welding pin is pressed. The heating conditions are appropriately set according to the area of ​​the joint portion 98e, the materials of the insulating film 98 and the collectors 70 and 75, etc. As heating conditions, the diameter of the welding pin, the pressure of pressing the welding pin, the temperature, the heating time, etc. can be adjusted.

[0070] <Step of accommodating the electrode body 40 in the case body 52>

[0071] In the step of housing the electrode body 40 in the case body 52 (hereinafter also referred to as the “housing step”), the electrode body 40 covered with the insulating film 98 is housed in the case body 52 (see Figure 2 ). In the process of storage, if Figure 2 As shown, the electrode body 40 in a state of being covered and restrained by the insulating film 98 is placed in the case body 52 by a known method. After the electrode body 40 is stored, the opening 52h is closed by welding the cover 54 on which the electrode body 40 is mounted to the case body 52. ​​The electrolyte is injected from the injection hole 55 to construct the power storage device assembly. The power storage device 100 can be manufactured by performing an initial charging process and an aging process on the power storage device assembly by a known method.

[0072] It should be noted that if vibration is applied to the power storage device, there is a situation where the electrode body moves in the shell. The electrode body is connected to the collector and the terminal via the tab. The tab extends from the core and is connected to the collector in a stacked state. If the electrode body moves in the shell, the collector and the electrode body installed on the cover of the shell move relative to each other. As a result, there is a concern that the tab is damaged. In the opinion of the inventors, since there is no constraint when covering the electrode body with an insulating film during the manufacture of the existing power storage device, only the assembly process of the insulating component is positioned, so the assembled insulating film is set to have a surplus size relative to the electrode body. In addition, when a fixing component (such as a tape having a substrate and an adhesive layer) is used to fix the electrode body, the manufacturing cost may increase due to the need for additional processes and the increase in the number of components.

[0073] The power storage device 100 manufactured in the above-mentioned embodiment includes an electrode body 40, a shell body 52, a cover 54, terminals 60, 65, an insulating member 94, collectors 70, 75 and an insulating film 98. The electrode body 40 has tabs 42, 44. The shell body 52 has an opening 52h. The shell body 52 accommodates the electrode body 40. The cover 54 is a member that blocks the opening 52h. The terminals 60, 65 are mounted on the cover 54. An insulating member 94 is sandwiched between the cover 54 and the terminals 60, 65. The collectors 70, 75 are connected to the terminals 60, 65 and the tabs 42, 44 of the electrode body 40. The insulating film 98 is arranged in the shell body 52 in a manner covering the electrode body 40. The insulating film 98 is composed of a resin film that insulates the shell body 52 from the electrode body 40. The insulating film 98 is bonded to the collectors 70, 75.

[0074] In the power storage device 100, the insulating film 98 is bonded to the current collectors 70 and 75 while the electrode body 40 is covered with the insulating film 98. The electrode body 40 is covered with the insulating film 98 while a restraining pressure is applied, and the insulating film 98 is connected to the current collectors 70 and 75. According to the above structure, the relative movement of the electrode body 40 with respect to the current collectors 70 and 75 can be suppressed. As a result, it is difficult for a load to be applied to the tabs 42 and 44, and damage to the tabs 42 and 44 can be suppressed.

[0075] Insulating film 98 is bonded to current collectors 70 and 75 to constrain electrode body 40 without using additional parts such as fixing members. Therefore, a structure for constraining electrode body 40 can be provided without increasing the number of parts, thereby reducing manufacturing costs and energy required for manufacturing.

[0076] In the power storage device 100, a portion of the current collectors 70 and 75 is welded to the insulating film 98. Here, the relative movement between the electrode body 40 and the current collectors 70 and 75 can be suppressed without using additional fixing components, and the damage to the tabs 42 and 44 can be suppressed. As a result, the number of components can be suppressed. In addition, the welding of the current collectors 70 and 75 and the insulating film 98 can be carried out simultaneously when the electrode body 40 is covered with the insulating film 98 and the first side portion 98c1 and the second side portion 98c2 are welded. Therefore, the electrode body 40 can be constrained without providing a new process for fixing the electrode body 40 using fixing components. As a result, the manufacturing cost can be reduced and the energy spent on manufacturing can be reduced.

[0077] In the above-described embodiment, for the boundaries B1 to B4, the size of the insulating film 98 is set so that when the electrode body 40 is covered with the insulating film 98, the gap between the electrode body 40 and the insulating film 98 is minimized on the side circumference of the electrode body 40. As a result, the electrode body 40 is easily constrained by the insulating film 98. As a result, damage to the tabs 42 and 44 during the manufacture of the power storage device 100 can be suppressed.

[0078] However, the position and the joining method of the joining portion 98e are not limited to the above-described embodiment. For example, the position and the range of the joining portion 98e can be appropriately set from the viewpoint of suppressing damage to the tabs 42 and 44 and the viewpoint of productivity.

[0079] Figure 8 FIG. 4 is a perspective view of the electrode body 40 covered with the insulating film 98. Figure 8 In FIG. 1 , the side surface of the electrode body 40 covered with the insulating film 98 is shown in an enlarged manner. Figure 8 In the figure, the structure inside the insulating film 98 is shown by a dotted line. Here, the position of the joint 98e is described by taking the positive electrode second current collector 72 as an example. Since the negative electrode side can also have the same structure, the detailed description is omitted. Figure 8As shown, the second current collector 72 includes a lower portion 72a connected to the pole tab 42 and an upper portion 72b connected to the first current collector 71. The lower portion 72a and the upper portion 72b extend in the up-down direction. A step is provided between the lower portion 72a and the upper portion 72b, and the lower portion 72a is located at a position closer to the outside than the upper portion 72b. In addition, the shape of the second current collector 72 is not limited to this mode. For example, the second current collector 72 may also be a flat plate without a step.

[0080] The joint portion 98e can be provided at a position in contact with the most outwardly protruding portion (the lower portion 72a in this embodiment) of the current collector 70. Thus, the electrode body 40 can be firmly constrained by the insulating film 98. In addition, the joint portion 98e can also be provided in a region R connected to the tab 42 at a corresponding position on the opposite side. Thus, the load applied to the joint portion 98e during joining can be reduced.

[0081] It is preferred that the joint portion 98e is set in the widest possible range in the lower portion 72a. However, from the viewpoint of productivity, the position of the joint portion 98e may be set at a part of the position in contact with the lower portion 72a. From the viewpoint of the pressure applied during joining and the viewpoint of expanding the joining range, welding pins that can achieve welding may be used at multiple points.

[0082] From the viewpoint of preventing poor bonding due to positional displacement, the position of the bonding portion 98e can be set at a part of the position in contact with the lower portion 72a. In addition, when a plurality of electrode bodies 40 are covered with the insulating film 98, the bonding portion 98e can be set at a position in contact with the current collector 70 connected to the electrode body 40 disposed in the center. Thus, the electrode body 40 can be stably constrained.

[0083] In the above-mentioned embodiment, the joining of the collectors 70, 75 and the insulating film 98 is achieved by melting the insulating film 98 and the collectors 70, 75 by heating. However, the joining of the insulating film 98 and the collectors 70, 75 is not limited to the above-mentioned manner. A portion of the collectors 70, 75 can be joined to a portion of the insulating film 98 (the joining portion 98e in this embodiment) via an adhesive layer. For example, in the process of preparing the electrode body 40, an adhesive layer can be formed on a portion of the collectors 70, 75. When a joining portion 98e is provided at a position where the first side portion 98c1 of the insulating film 98 overlaps with the second side portion 98c2, the adhesive layer can also be formed on the joining portion 98e of the insulating film 98. Although not particularly limited, as the adhesive layer, for example, a rubber-based adhesive can be used. In the process of constraining, the portions of the collectors 70, 75 each having an adhesive layer formed thereon can be joined to a portion of the insulating film 98 (the joining portion 98e in this embodiment).

[0084] By using an adhesive layer, it is easy to form a joint portion over a wide range relative to the object to be joined (in this embodiment, the collectors 70 and 75). Therefore, it is easy to join the collectors 70 and 75 to the insulating film 98 over a wide range without reducing productivity. By joining the collectors 70 and 75 to the insulating film 98 over a wide range, the electrode body 40 can be more firmly constrained. In addition, the adhesive layer can also be formed on the flat portion 40f of the electrode body 40. As a result, the wide surface of the electrode body 40 is joined to the insulating film 98. As a result, the electrode body 40 can be more firmly constrained.

[0085] The position where the insulating film 98 is joined to the current collectors 70 and 75 can be subjected to a surface treatment for improving the bonding property. For example, in the process of preparing the electrode body 40, the portion of the current collectors 70 and 75 that is joined to the insulating film 98 can be subjected to a surface treatment. In the process of performing the constraint, the current collectors 70 and 75 can be joined to the insulating film 98 at the portion to which the surface treatment has been applied. As a surface treatment, a treatment that increases the surface roughness of the current collectors 70 and 75 can be used. As surface treatments, for example, laser marking, shot peening, etching, and the like can be cited. From the viewpoint of the impact on productivity and other than the joining position, it is preferred that the surface treatment is limited to the joining portion. From the viewpoint of limiting the processing capacity of the surface treatment and the range of the surface treatment, it is preferred to process the surface of the current collectors 70 and 75 by laser marking (laser marker) that is easy to perform surface treatment locally on the object.

[0086] In the above, the insulating film 98 is bonded to the current collectors 70 and 75 to constrain the electrode body 40. However, as long as the electrode body 40 is constrained and the damage to the tabs 42 and 44 is suppressed, the member to which the insulating film 98 is bonded is not limited to the current collectors 70 and 75. The insulating film 98 may be bonded to, for example, the cover 54, the insulating member 94, etc.

[0087] Fig. 9 FIG. 5 is an enlarged view of the cover 54 connected to the electrode body 40. Fig. 9 , the electrode body 40 and the side surface of the cover 54 viewed along the thickness direction (X direction) of the electrode body 40 are shown. Fig. 9 In FIG. 1 , the position where the insulating film 98 can be arranged is indicated by a double-dashed line. Fig. 9As shown, the cover 54 protrudes more than the second current collector 72 in the width direction Y. The insulating film 98 can be installed on the protruding portion. For example, the upper portion of the insulating film 98 is bent while the insulating film 98 is along the current collector 70 (in this embodiment, the lower portion 72a of the second current collector 72). The bent portion of the insulating film 98 can be joined to the bottom surface 54a of the cover 54. Thus, the insulating film 98 is positioned and the electrode body 40 is difficult to move in the width direction Y. In addition, the insulating film 98 can also be joined to the side 94a1 of the base 94a of the insulating component 94. At this time, it is preferred that the insulating film 98 is in contact with the flat portion 40f of the electrode body 40. Thus, the movement of the electrode body 40 along the thickness direction is easily restricted. As a result, the electrode body 40 can be firmly constrained and damage to the tab 42 can be suppressed.

[0088] Above, various descriptions have been made to the technology disclosed herein. As long as no particular mention is made, the embodiments cited here, etc. do not limit the present invention. In addition, the technology disclosed herein can be subjected to various changes, and as long as no special problems are generated, each component, each process mentioned here can be appropriately omitted or appropriately combined. In addition, this specification includes the disclosures recorded in the following items.

[0089] Item 1:

[0090] An electric storage device comprising:

[0091] An electrode body having a tab;

[0092] The shell body has an opening and contains the electrode body;

[0093] A cover for sealing the opening;

[0094] A terminal is mounted on the cover;

[0095] An insulating member, sandwiched between the cover and the terminal;

[0096] a current collector connected to the terminal and the tab of the electrode body; and

[0097] An insulating film made of a resin film is arranged in the case body so as to cover the electrode body and insulate the case body from the electrode body.

[0098] The insulating film is bonded to at least one of the cover, the insulating member attached to the cover, and the current collector.

[0099] Item 2:

[0100] The power storage device according to item 1, wherein

[0101] The insulating film is bonded to the current collector.

[0102] Item 3:

[0103] The power storage device according to item 2, wherein:

[0104] A portion of the current collector is fused to a portion of the insulating film.

[0105] Item 4:

[0106] The power storage device according to item 2, wherein:

[0107] A portion of the current collector and a portion of the insulating film are bonded to each other via an adhesive layer.

[0108] Item 5:

[0109] The power storage device according to any one of items 2 to 4, wherein

[0110] The current collector is subjected to surface treatment at a portion thereof that is bonded to the insulating film.

[0111] Item 6:

[0112] A method for manufacturing an electric storage device, comprising:

[0113] A step of preparing a case body having an opening and accommodating the electrode body;

[0114] a step of preparing the electrode body mounted on the cover via a current collector;

[0115] a step of preparing an insulating film composed of a resin film;

[0116] A step of constraining the electrode body using the insulating film; and

[0117] a step of housing the electrode body covered with the insulating film in the case body,

[0118] The electrode body prepared in the step of preparing the electrode body is connected to the current collector via the tab, and a terminal is attached to the cover via an insulating member.

[0119] The step of constraining includes bonding the insulating film to at least one of the cover, an insulating member attached to the cover, and the current collector.

[0120] Item 7:

[0121] The method for manufacturing an electric storage device according to item 6, wherein:

[0122] In the step of constraining, a portion of the insulating film is bonded to a portion of the current collector.

[0123] Item 8:

[0124] The method for manufacturing an electric storage device according to item 7, wherein:

[0125] In the step of constraining, a portion of the insulating film is heated to fuse the portion of the insulating film and at least a portion of the current collector.

[0126] Item 9:

[0127] The method for manufacturing an electric storage device according to item 7, wherein:

[0128] In the step of preparing the electrode body, a bonding layer is formed on a portion of the current collector.

[0129] In the step of constraining, the portion of the current collector where the adhesive layer is formed is bonded to a portion of the insulating film.

[0130] Item 10:

[0131] The method for manufacturing an electric storage device according to any one of items 7 to 9, wherein:

[0132] In the step of preparing the electrode body, a surface treatment is performed on a portion of the current collector that is bonded to the insulating film.

[0133] In the step of constraining, the current collector and the insulating film are bonded to the portion subjected to the surface treatment.

Claims

1. An electric storage device, characterized in that: have: An electrode body having a tab; A shell body having an opening and accommodating the electrode body; A cover for sealing the opening; a terminal mounted on the cover; an insulating member, sandwiched between the cover and the terminal; A current collector connected to the terminal and the tab of the electrode body; as well as An insulating film made of a resin film is arranged in the case body so as to cover the electrode body and insulate the case body from the electrode body. The insulating film is bonded to at least one of the cover, the insulating member attached to the cover, and the current collector.

2. The power storage device according to claim 1, characterized in that The insulating film is bonded to the current collector.

3. The power storage device according to claim 2, characterized in that A portion of the current collector is fused to a portion of the insulating film.

4. The power storage device according to claim 2, characterized in that A portion of the current collector and a portion of the insulating film are bonded to each other via an adhesive layer.

5. The power storage device according to any one of claims 2 to 4, characterized in that: The current collector is subjected to surface treatment at a portion thereof that is bonded to the insulating film.

6. A method for manufacturing an electric storage device, characterized in that: include: A step of preparing a case body having an opening and accommodating the electrode body; a step of preparing the electrode body to be mounted on the cover via a current collector; a step of preparing an insulating film composed of a resin film; A step of constraining the electrode body by using the insulating film; as well as a step of housing the electrode body covered with the insulating film in the case body, The electrode body prepared in the step of preparing the electrode body is connected to the current collector via the tab, and the terminal is attached to the cover via an insulating member. The step of constraining includes bonding the insulating film to at least one of the cover, an insulating member attached to the cover, and the current collector.

7. The method for manufacturing an electric storage device according to claim 6, wherein: In the step of constraining, a portion of the insulating film is bonded to a portion of the current collector.

8. The method for manufacturing an electric storage device according to claim 7, wherein: In the step of constraining, a portion of the insulating film is heated to fuse the portion of the insulating film and at least a portion of the current collector.

9. The method for manufacturing an electric storage device according to claim 7, wherein: In the step of preparing the electrode body, an adhesive layer is formed on a portion of the current collector. In the step of constraining, a portion of the current collector where the adhesive layer is formed is bonded to a portion of the insulating film.

10. The method for manufacturing an electric storage device according to any one of claims 7 to 9, characterized in that: In the step of preparing the electrode body, a surface treatment is performed on a portion of the current collector that is bonded to the insulating film. In the step of constraining, the current collector and the insulating film are bonded to the portion subjected to the surface treatment.

Images