Secondary battery

Abstract

To provide a secondary battery capable of improving structural efficiency.SOLUTION: A secondary battery includes a power generating element and an exterior portion that houses the power generating element, the exterior portion includes a cylindrical portion with openings on two opposing sides, a cap terminal arranged in each opening, and a resin arranged between the cylindrical portion and the cap terminal, the cylindrical portion and the cap terminal are integrated with the resin, the current collector of the power generating element and the cap terminal are coupled electrically, and the power generating element includes at least one current collector, the inner surface of the cap terminal includes at least one slit portion, and the current collector is arranged in the slit portion, thereby electrically connecting the current collector and the cap terminal.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present application relates to a secondary battery. [Background technology]

[0002] Batteries such as lithium ion secondary batteries are widely used as portable power sources for personal computers and mobile terminals, and as power sources for driving vehicles. A laminated battery is known as an example of a battery. A laminated battery has a structure in which a power generating element is sealed inside a laminated exterior body formed by overlapping film-like laminate sheets. The laminated battery also has a seal area formed by welding edges of laminated exterior bodies arranged opposite each other, with terminals electrically connected to the power generating element protruding outward from the inside of the laminated exterior body. This seals the power generating element inside the laminated exterior body. The laminated battery also has a seal area formed by overlapping and welding laminate sheets on the outside of the power generating element.

[0003] Conventionally, miniaturization of battery structures has been studied. For example, Patent Document 1 discloses a technique for miniaturizing a laminated battery by folding a seal area provided at the end of the battery. Patent Document 2 discloses a technique for miniaturizing a laminated battery using a lid by folding a seal area provided at the end of the battery. Patent Document 3 discloses a lithium polymer secondary battery structure including an exterior material that surrounds the outside of an electrode assembly and first and second covers that seal the exterior material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-173900 A [Patent Document 2] Japanese Patent Application Publication No. 2-37661 [Patent Document 3] JP 2011-108623 A Summary of the Invention [Problem to be solved by the invention]

[0005] Although the techniques disclosed in Patent Documents 1 to 3 make it possible to reduce the size of laminate-type batteries, further improvements in the structural efficiency of secondary batteries have been desired.

[0006] A laminated battery can be made smaller by shortening the width of the sealing area (seal width) that sandwiches the electrode terminal, for example, but the seal width usually needs to be set to a length of more than 3 mm. This is for the following reasons. (1) If the seal width is too short, heat welding cannot be performed properly, which may result in poor sealing. (2) Since the laminated exterior body is not very rigid, if the seal width is too short, the adhesion of the sealing area may peel off due to an external impact, and the adhesive surface may not be able to be maintained. In addition, in a laminated battery having a lid, when the lid is tilted due to an external impact, if the seal width is short, the correction force to return the tilt to its original state is weak, so the adhesive surface may not be properly maintained. (3) During heat welding, if the outer peripheral surface of the terminal or lid is not parallel to the adhesive surface of the laminated exterior body, if the seal width is short, the correction force to return the tilt to its original state is weak, which increases the probability of poor sealing and inability to perform heat welding properly. (4) When the seal width is short, the pressure per area applied to the seal area by the heat welding head becomes large, and there is a risk that the metal layer inside the laminate exterior body will go over the insulating layer and bite into the terminal. If the metal layer bites into the terminal, it will cause a short circuit, which is undesirable. For these reasons, it has been difficult to reduce the seal width and make the laminated battery smaller.

[0007] Therefore, an object of the present disclosure is to provide a secondary battery that can improve structural efficiency. [Means for solving the problem]

[0008] The present application discloses a secondary battery comprising a power generating element and an exterior portion that houses the power generating element, the exterior portion having a tubular portion with openings on two opposing sides, a cap terminal disposed in each opening, and resin disposed between the tubular portion and the cap terminal, the tubular portion and the cap terminal being integrated with the resin, a current collector of the power generating element and the cap terminal being electrically connected, the power generating element having at least one current collector, the inner surface of the cap terminal having at least one slit portion, and the current collector being disposed in the slit portion, thereby electrically connecting the current collector and the cap terminal.

[0009] The present application also discloses a secondary battery comprising a power generating element and an exterior part that houses the power generating element, the exterior part having a tubular part with openings on two opposing sides, cap terminals arranged in each opening, and resin arranged between the tubular part and the cap terminal, the tubular part and the cap terminal being integrated with the resin, a current collector of the power generating element and the cap terminal being electrically connected, and an insulating sheet having a slit part through which at least one current collector is inserted is arranged between the power generating element and the cap terminal.

[0010] The present application also discloses a secondary battery comprising a power generating element and an exterior portion that houses the power generating element, the exterior portion having a cylindrical portion with openings on two opposing sides, cap terminals arranged in each opening, and resin arranged between the cylindrical portion and the cap terminal, the cylindrical portion and the cap terminal being integrated with the resin, a current collector of the power generating element and the cap terminal being electrically connected, the cap terminal having a convex portion protruding outside the cylindrical portion, and resin being arranged on at least a portion of the outer peripheral surface of the convex portion.

[0011] The present application also provides a battery comprising a power generating element and an exterior part that houses the power generating element, the exterior part comprising: The present invention discloses a secondary battery having a cylindrical portion with openings on two opposing sides, a cap terminal disposed in each opening, and a resin disposed between the cylindrical portion and the cap terminal, the cylindrical portion and the cap terminal being integrated with the resin, a current collector of a power generating element and the cap terminal being electrically connected, and the cap terminal having protrusions protruding inward from at least two or more ends of an inner surface of the cap terminal.

[0012] The present application also discloses a secondary battery comprising a power generating element and an exterior part that houses the power generating element, the exterior part having a tubular part with openings on two opposing sides, cap terminals arranged in each opening, and resin arranged between the tubular part and the cap terminal, the tubular part and the cap terminal being integrated with the resin, a current collector of the power generating element and the cap terminal being electrically connected, the tubular part being composed of a plurality of metal plates and a third resin, the metal plates having protrusions protruding from their ends, the metal plates extending in a direction in which the protrusions face each other and arranged with gaps, and the third resin being arranged so as to fill at least a portion of the gaps existing between the metal plates.

[0013] The present application also discloses a secondary battery comprising a power generating element and an exterior part that houses the power generating element, the exterior part having a tubular part with openings on two opposing sides, cap terminals arranged in each opening, and resin arranged between the tubular part and the cap terminal, the tubular part and the cap terminal being integrated with the resin, and the power generating element's current collector and the cap terminal being electrically connected, the tubular part being composed of a plurality of metal plates and a third resin, the metal plates being arranged to form openings, and the third resin being arranged to fill at least a portion of the gaps existing between the metal plates.

[0014] The present application also discloses a secondary battery comprising a power generating element and an exterior part that houses the power generating element, the exterior part having a cylindrical part with openings on two opposing sides, cap terminals arranged in each opening, and resin arranged between the cylindrical part and the cap terminal, the cylindrical part and the cap terminal being integrated with the resin, a current collector of the power generating element and the cap terminal being electrically connected, the cylindrical part being composed of a metal plate and a third resin, the metal plate being formed into a cylindrical shape, ends of the metal plate being overlapped on one side of the cylindrical part, and the third resin being arranged so as to fill at least a portion of the gap between the metal plates.

[0015] In the secondary battery, the current collector may be electrically connected to the cover terminal in a curved state.

[0016] In the secondary battery, the exterior part may have a second resin filled therein, and the cylindrical part, the cover terminal, and the power generating element may be integrated with the second resin.

[0017] In the secondary battery, the cylindrical portion may be a cylindrical metal body or a cylindrical metal laminate film. Effect of the Invention

[0018] According to the secondary battery of the present disclosure, it is possible to improve the structural efficiency. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of a secondary battery 100. [Diagram 2] FIG. 2 is a longitudinal sectional view taken along line II-II in FIG. [Diagram 3] 1A is a plan view of the cylindrical portion 21. FIG. 1B is a widthwise cross-sectional view of the cylindrical portion 21. FIG. 1C is a side view of the cylindrical portion 21 as viewed from the widthwise direction. [Figure 4] 1A is a cross-sectional view of the vicinity of an opening 21a of a tubular portion 21 having protrusions 21b at each end of a surface in the thickness direction, and FIG. 1B is a cross-sectional view of the vicinity of an opening 21a of a tubular portion 21 having protrusions 21b bent inward. [Diagram 5] 1A is a perspective view of the cover terminal 22. FIG. 1B is a front view of the cover terminal 22 observed from the direction b in FIG. 1A. FIG. 1C is a side view of the cover terminal 22 observed from the direction c in FIG. [Figure 6] This is an example of a cover terminal 122 that does not have a protrusion 22d. [Figure 7] 13(a) is a side view of a cover terminal 222 having protrusions 22h disposed on both ends of a surface 22e in the thickness direction, and FIG. [Figure 8] FIG. 1 is a comparison of longitudinal cross-sectional views of a conventional laminated battery (a) and a secondary battery 100 (b). [Figure 9]FIG. 1 is a plan view comparing a conventional laminated battery (a) with a secondary battery 100 (b). [Figure 10] 1 is a longitudinal cross-sectional view of a secondary battery 101 in which the entire inside of an exterior part 20 is filled with a second resin 24. FIG. [Figure 11] 1 is a longitudinal cross-sectional view of a secondary battery 102 in which a power generating element 10 is wrapped in a resin film 12. FIG. [Figure 12] FIG. 2 is a plan view of a power generating element 10 wrapped in a resin film 12. [Figure 13] 1A is a plan view of the cylindrical portion 121. FIG. [Figure 14] 1A is a plan view of the cylindrical portion 221. FIG. [Figure 15] 13 is a diagram showing one cooling mode of a secondary battery using a cylindrical portion 221. FIG. [Figure 16] FIG. 2 is a perspective view of a secondary battery 103. [Figure 17] 16A, 16B, 16C, and 16D are longitudinal sectional views taken along lines XVIIa-XVIIa, XVIIb-XVIIb, and XVIIc-XVIIc, respectively. [Figure 18] 13A is a perspective view of the cover terminal 322. FIG. 13B is a front view of the cover terminal 322 observed from the direction b in FIG. 13A. FIG. 13C is a rear view of the cover terminal 22 observed from the direction c in FIG. [Figure 19] 1A and 1B are front and plan views of a lid terminal having a slit for inserting a current collector 311 from a side surface, (a) an example of a lid terminal having two protrusions, and (b) an example of a lid terminal having one protrusion. [Figure 20] This is an example of a configuration in which two current collectors 311 are arranged in one slit portion 322j. [Figure 21](a) An example of an arrangement of the insulating sheet 325 between the power generating element 10 and the cover terminal 322. (b) An example of an arrangement of the insulating sheet 325 when two current collectors 311 are arranged in one slit portion 322j. (c) An example of an arrangement of the insulating sheet 325 when two current collectors 311 are arranged in one slit portion 322j, and when the opening 325a of the slit 325a of the insulating sheet 325 has a shape that is wide in the thickness direction. [Figure 22] This is an example of a configuration in which an insulating sheet 325 is disposed between the surface of the power generating element 310 in the thickness direction and the inner surface of the cylindrical portion 321 in the thickness direction. [Figure 23] FIG. 1 is a comparison of longitudinal cross-sectional views of a conventional laminated battery (a), a secondary battery 100 (b), and a secondary battery 103 (c). [Figure 24] FIG. 2 is a diagram illustrating water vapor diffusion inside a resin. [Diagram 25] (a) This is an example of an embodiment in which a second resin 324 is disposed between the thickness direction surface of the power generating element 310 and the thickness direction inner surface of the exterior part. (b) This is an example of an embodiment in which an insulating sheet 325 is further disposed between the cover terminal 322 and the power generating element 310. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The secondary battery of the present disclosure will be described using secondary batteries 100 to 103 as an embodiment. Fig. 1 shows a perspective view of the secondary battery 100. Fig. 2 shows a longitudinal cross-sectional view taken along line II-II in Fig. 1. In Figs. 1 and 2, the longitudinal direction of the secondary battery 100 is represented by x, the width direction of the secondary battery 100 is represented by y, and the thickness direction of the secondary battery 100 is represented by z. These directions are perpendicular to each other.

[0021] The secondary battery 100 includes a power generating element 10 and an exterior part 20 that houses the power generating element 10. The exterior part 20 includes a cylindrical part 21 having openings 21a on two opposing sides, cover terminals 22 (positive electrode cover terminal 22a and negative electrode cover terminal 22b) arranged in each opening 21a, and a resin 23 (hereinafter sometimes referred to as "first resin 23") arranged between the cylindrical part 21 and the cover terminal 22, and the cylindrical part 21 and the cover terminal 22 are integrated with the resin 23. In addition, the current collectors 11 (positive electrode current collector 11a and negative electrode current collector 11b) of the power generating element 10 are electrically connected to the cover terminals 22.

[0022] <Power generation element 10> The power generating element 10 is formed by stacking a positive electrode collector 11a, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode collector 11b (hereinafter, these may be collectively referred to as "electrode elements"). The electrode elements are stacked in the thickness direction. There is no particular limit to the number of each electrode element to be stacked. The power generating element 10 in FIG. 2 has a configuration in which a plurality of these electrode elements are stacked. Furthermore, these electrode elements may be stacked so as to be electrically connected in series, or may be stacked so as to be electrically connected in parallel.

[0023] The power generating element 10 in FIG. 2 has a sheet-like shape and is rectangular in plan view. However, the shape of the power generating element 10 is not particularly limited as long as it has a shape that can be accommodated inside the exterior part 20. As shown in FIG. 2, each current collector 11 of the power generating element 10 is electrically connected to each lid terminal 22 via a current collector tab. Specifically, the positive current collector 11a is electrically connected to the positive electrode lid terminal 22a via a positive current collector tab. The negative current collector 11b is electrically connected to the negative electrode lid terminal 22b via a negative current collector tab. However, each current collector 11 may be electrically connected to the lid terminal 22 without via a current collector tab.

[0024] As described above, the power generating element 10 has an electrode laminate in which electrode elements are laminated, and a current collector tab extending from the electrode laminate. In this specification, the power generating element 10 may refer to the entire power generating element 10 including the electrode laminate and the current collector tab, or may refer to only the electrode laminate. When the power generating element 10 refers to only the electrode laminate, it may be described as "power generating element 10 (electrode laminate)". In addition, in this specification, the current collector tabs (positive electrode current collector tab, negative electrode current collector tab) may be described as current collectors 11 (positive electrode current collector 11a, negative electrode current collector 11b).

[0025] The power generating element 10 may be subjected to a predetermined insulation treatment in order to prevent a short circuit due to contact with the cylindrical portion 21. For example, the power generating element 10 may be wrapped in an insulating film, an insulating sheet may be disposed between the power generating element 10 and the cylindrical portion 21, or insulating tape may be attached to the inner surface of the power generating element 10 or the cylindrical portion 21. In this manner, an insulation treatment may be performed in which a predetermined insulating layer is disposed on the outer periphery of the power generating element 10.

[0026] In the thickness direction, the power generating element 10 and the cylindrical portion 21 may be in contact with each other as long as either of them is insulated. In this case, the thickness of the cover terminal 22 may be thinner than the thickness of the power generating element 10 by the thickness of the first resin 23 filled between the cylindrical portion 21 and the cover terminal 22. Specifically, the thickness of the power generating element 10 may be equal to or greater than the thickness of the cover terminal 22. Furthermore, both sides of the power generating element 10 in the thickness direction may be in contact with the inner surface of the cylindrical portion 21. In other words, the thickness of the power generating element 10 may satisfy the following: thickness of the cylindrical portion 21>thickness of the inner surface of the cylindrical portion 21≧thickness of the power generating element 10≧thickness of the cover terminal. This allows the excess space to be eliminated, and the structural efficiency of the secondary battery 100 to be further improved.

[0027] Similarly, the power generating element 10 and the cylindrical portion 21 may be in contact with each other in the width direction, provided that either of them is insulated. In this case, the width of the cover terminal 22 may be thinner than the width of the power generating element 10 by the thickness of the first resin 23 filled between the cylindrical portion 21 and the cover terminal 22. Specifically, the width of the power generating element 10 may be equal to or larger than the width of the cover terminal 22. Furthermore, both sides of the power generating element 10 in the width direction may be in contact with the inner surface of the cylindrical portion 21. In other words, the width of the power generating element 10 may satisfy the following: width of the cylindrical portion 21>width of the inner surface of the cylindrical portion 21≧width of the power generating element 10≧width of the cover terminal. This allows the removal of unnecessary space, thereby further improving the structural efficiency of the secondary battery 100.

[0028] The power generating element 10 may be a solid-state battery or a liquid battery. A solid-state battery is preferable. The type of the power generating element 10 is not particularly limited, and it can be applied to any secondary battery. For example, it may be a power generating element for a lithium-ion secondary battery or a power generating element for a sodium-ion secondary battery. The material of the power generating element for a lithium-ion secondary battery will be described below.

[0029] (Positive electrode current collector 11a, negative electrode current collector 11b) The positive electrode current collector 11a and the negative electrode current collector 11b are sheet-shaped metal foils. The metals constituting the positive electrode current collector 11a and the negative electrode current collector 11b are not particularly limited, and examples thereof include Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, and the like. The metal constituting the positive electrode current collector 11a is preferably Al. The material constituting the negative electrode current collector 11b is preferably Cu. In addition, the positive electrode current collector 11a and the negative electrode current collector 11b may each have a current collector tab. Each current collector tab may be made of the same material as each current collector.

[0030] The positive electrode current collector 11a and the negative electrode current collector 11b may have some coating layer (e.g., a carbon coating layer) on their surfaces to adjust the resistance. The thickness of the positive electrode current collector 11a and the negative electrode current collector 11b may be, for example, 0.1 μm or more and 1 mm or less.

[0031] (Cathode active material layer) The positive electrode active material layer is a sheet-like layer containing a positive electrode active material. The positive electrode active material is not particularly limited as long as it is a positive electrode active material that can be used in a lithium ion secondary battery. For example, various lithium-containing composite oxides such as lithium cobalt oxide, lithium nickel oxide, lithium manganate, lithium nickel cobalt manganate, and spinel-based lithium compounds can be mentioned.

[0032] The positive electrode active material layer may optionally contain a conductive assistant and a binder. The binder is not particularly limited as long as it is a binder that can be used in lithium ion secondary batteries. Examples include butadiene rubber (BR), butylene rubber (IIR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVdF), and the like. The conductive assistant is not particularly limited as long as it is a conductive assistant that can be used in lithium ion secondary batteries. Examples include carbon materials such as acetylene black and ketjen black, and metal materials such as nickel, aluminum, and stainless steel.

[0033] When the secondary battery 100 is an all-solid-state battery, the positive electrode active material layer may optionally contain a solid electrolyte. The solid electrolyte is not particularly limited as long as it is a solid electrolyte that can be used in a lithium ion secondary battery. For example, it may be an organic polymer electrolyte or an inorganic solid electrolyte. An inorganic solid electrolyte is preferable. This is because it has higher ionic conductivity and superior heat resistance compared to an organic polymer electrolyte. The inorganic solid electrolyte may be an oxide solid electrolyte or a sulfide solid electrolyte. A sulfide solid electrolyte is preferable. Examples of oxide solid electrolytes include lithium lanthanum zirconate, LiPON, Li 1+X Al X Ge 2-XExamples of the sulfide solid electrolyte include Li2S-P2S5, Li2S-SiS2, LiI-Li2S-SiS2, LiI-Si2S-P2S5, Li2S-P2S5-LiI-LiBr, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li2S-P2S5-GeS2, etc.

[0034] The content of each component in the positive electrode active material layer may be appropriately set depending on the purpose. The surface of the positive electrode active material may be covered with an oxide layer such as a lithium niobate layer, a lithium titanate layer, or a lithium phosphate layer. The thickness of the positive electrode active material layer may be, for example, 0.1 μm or more and 1 mm or less.

[0035] (Negative electrode active material layer) The negative electrode active material layer is a sheet-like layer containing a negative electrode active material. The negative electrode active material is not particularly limited as long as it is a negative electrode active material that can be used in a lithium ion secondary battery. For example, silicon and Si alloys, silicon-based active materials such as silicon oxide, carbon-based active materials such as graphite and hard carbon, various oxide-based active materials such as lithium titanate, metallic lithium, lithium alloys, etc. can be mentioned.

[0036] The negative electrode active material layer may optionally contain a conductive assistant and a binder. The conductive assistant and the binder may be appropriately selected from the conductive assistant and the binder that can be used in the positive electrode active material layer. In addition, when the secondary battery 100 is an all-solid-state battery, the negative electrode active material layer may optionally contain a solid electrolyte. The solid electrolyte may be appropriately selected from the solid electrolytes that can be used in the positive electrode active material layer.

[0037] The content of each component in the negative electrode active material layer may be appropriately set depending on the purpose. The thickness of the negative electrode active material layer may be, for example, 0.1 μm or more and 1 mm or less.

[0038] (electrolyte layer) When the secondary battery 100 is an all-solid-state battery, the electrolyte layer is a sheet-shaped solid electrolyte layer. The solid electrolyte layer includes a solid electrolyte. The solid electrolyte can be appropriately selected from solid electrolytes that can be used in the positive electrode active material layer. The solid electrolyte layer may also include a binder. The binder can be appropriately selected from binders that can be used in the positive electrode active material layer. The content of each component in the solid electrolyte layer may be appropriately set depending on the purpose. The thickness of the solid electrolyte layer may be, for example, 0.1 μm or more and 1 mm or less.

[0039] When the secondary battery 100 is a liquid battery, the electrolyte layer includes an electrolyte and a separator. The electrolyte and the separator are not particularly limited as long as they are electrolyte and separator that can be used in a lithium ion secondary battery. The separator may be, for example, a porous sheet (film) made of polyolefin such as polyethylene (PE) or polypropylene (PP). The thickness of the separator may be, for example, 0.1 μm or more and 1 mm or less. The electrolyte usually contains a non-aqueous solvent and a supporting salt. Examples of the non-aqueous solvent include carbonates, ethers, esters, nitriles, sulfones, lactones, etc. Examples of the supporting salt include LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethane)sulfonimide (LiTFSI), etc. The concentration of the supporting salt in the electrolyte is not particularly limited, but may be, for example, 0.5 mol / L or more and 5 mol / L or less. The electrolyte may further contain any optional components such as a gas generating agent, a film forming agent, a dispersing agent, a thickening agent, etc.

[0040] <Exterior part 20> The exterior part 20 has a tubular part 21 having openings 21a on two opposing sides, cover terminals 22 (positive electrode cover terminal 22a and negative electrode cover terminal 22b) arranged in each opening 21a, and a first resin 23 arranged between the tubular part 21 and the cover terminals 22, and the tubular part 21 and the cover terminals 22 are integrated by the first resin 23.

[0041] (Cylindrical portion 21) The cylindrical portion 21 has a hollow shape with openings 21a on two opposing surfaces. The openings 21a are provided on both longitudinal surfaces of the cylindrical portion 21. The cross-sectional shape of the cylindrical portion 21 in the width direction is rectangular. However, the cross-sectional shape of the cylindrical portion is not limited to this. Fig. 3 (a) shows a plan view of the cylindrical portion 21, (b) shows a cross-sectional view of the cylindrical portion 21 in the width direction, and (c) shows a side view of the cylindrical portion 21 as viewed from the width direction.

[0042] The cylindrical portion 21 is made of a metal having a high water vapor barrier property from the viewpoint of preventing deterioration of the power generating element. -4 g / m 2 ·24h or less. The lower the water vapor permeability, the higher the water vapor barrier property. Examples of such metals include aluminum, stainless steel, SUS, and duralumin. From the viewpoint of light weight and workability, aluminum may be used as the material for the cylindrical portion 21. Another advantage of aluminum is that it is inexpensive.

[0043] The water vapor permeability can be measured by the cup method in accordance with JIS Z 0208 or the gas chromatography method in accordance with JIS K 7129.

[0044] Here, the cylindrical portion 21 may be subjected to a predetermined insulating treatment from the viewpoint of suppressing a short circuit due to contact with the power generating element 10. For example, an insulating material such as an insulating sheet may be disposed between the power generating element 10 and the cylindrical portion 21. An insulating material may be disposed between the thickness direction surface of the power generating element 10 and the cylindrical portion 21. Also, an insulating material may be disposed between the width direction surface of the power generating element 10 and the cylindrical portion 21. This can suppress electrical connection between the power generating element 10 and the cylindrical portion 21, and suppress a short circuit of the secondary battery 100. Also, a metal laminate film (e.g., an aluminum laminate film) in which at least the inner surface of the cylindrical portion 21 is covered with an insulating resin may be used. This can suppress electrical connection between the power generating element 10 and the cylindrical portion 21 without the need to dispose an insulating material, and suppress a short circuit of the secondary battery 100. The metal laminate film is a multilayer body in which a resin (e.g., polypropylene, nylon, PET, etc.) is disposed on the surface of a metal layer. In this manner, an insulating process may be performed by disposing a predetermined insulating layer on the inner peripheral portion of the cylindrical portion 21 .

[0045] However, the thickness of the metal layer of a general metal laminate film is usually about 0.04 mm, which is relatively thin and therefore has a problem of low strength. Therefore, the cylindrical part 21 is preferably made of a metal having a thickness of, for example, 0.05 mm to 0.2 mm, and more preferably made of a metal having a thickness of 0.1 mm to 0.2 mm. In addition, a metal laminate film including a metal layer having a thickness in the above range may be used as the cylindrical part 21. When a metal laminate film is used for the cylindrical part 21, the metal laminate film is formed into a cylindrical shape.

[0046] The cylindrical portion 21 may have a protruding portion 21b at an end in the length direction. More specifically, the cylindrical portion 21 may have a protruding portion 21b at at least one of the thickness direction surface and the width direction surface at the end in the length direction. Providing the protruding portion 21b serves to ensure an adhesive area with the first resin 23 and improve adhesive strength. The protruding portion 21b refers to a portion that protrudes outward beyond the base material layer 22c of the cover terminal 22.

[0047] Fig. 4(a) shows a cross-sectional view of the vicinity of the opening 21a of the tubular portion 21 having the protrusions 21b at each end of the surface in the thickness direction, and Fig. 4(b) shows a cross-sectional view of the vicinity of the opening 21a of the tubular portion 21 having the protrusions 21b bent inward.

[0048] The cylindrical portion 21 shown in FIG. 4(a) has a protruding portion 21b at each end of the surface in the thickness direction. That is, the end of the surface in the thickness direction of the cylindrical portion 21 protrudes more than the end of the surface in the width direction of the cylindrical portion 21. As shown in FIG. 4(a), the cylindrical portion 21 has the protruding portion 21b, so that the adhesion area with the first resin 23 can be increased and the adhesive force can be improved. In other words, peeling of the first resin 23 can be suppressed. If the first resin 23 peels off, the water vapor barrier property cannot be ensured, which is undesirable. Also, as shown in FIG. 4(b), the protruding portion 21b may have a shape bent toward the inside of the cylindrical portion 21. This makes it easier to position the cover terminal 22. In this case, the opening formed by the two protruding portions 21 becomes the opening 21a.

[0049] The angle between the protrusion 21b and the surface of the cylindrical portion 21 (the surface having the protrusion 21b) is not particularly limited and can be any angle between 0° and 180°. It is preferably between 15° and 135°. The length of the protrusion 21b is not particularly limited, but is in the range of 0.5 mm to 2 mm, for example. However, it is adjusted so as not to exceed the surface 22f of the cover terminal 22 on the opening 21a side.

[0050] (Lid terminal 22) The lid terminals 22 (positive lid terminal 22a and negative lid terminal 22b) are disposed in the respective openings 21a of the cylindrical portion 21 and function as lids for the cylindrical portion 21. The lid terminals 22 also function as electrode terminals for the battery 100. Thus, the lid terminals 22 are characterized by having two functions, that is, a lid and an electrode terminal. Fig. 5(a) shows a perspective view of the lid terminal 22, (b) shows a front view of the lid terminal 22 observed from the direction b in (a), and (c) shows a side view of the lid terminal 22 observed from the direction c in (a).

[0051] The cover terminal 22 has a base layer 22c and a protruding portion 22d protruding outward from the base layer 22c. The base layer 22c has a rectangular outer peripheral shape, and has a surface 22e on the inside thereof that can be connected to each current collector 11. The protruding portion 22d has a rectangular shape that is one size smaller than the base layer 22c, and has a surface 22f on the outside thereof for electrically connecting to an external power source or power load. In addition, the cover terminal 22 has a predetermined step portion 22g at the connection portion between the base layer 22c and the protruding portion 22d. The step portion 22g is a combination of the outer peripheral portion of the protruding portion 22d and the outer surface of the base layer 22c. However, the outer peripheral shape of the base layer 22c is not particularly limited, and it is sufficient that the shape is in accordance with the width direction cross-sectional shape of the cylindrical portion 21. The outer peripheral shape of the protruding portion 22d is also not particularly limited. In addition, the cover terminal 22 does not have to have the protruding portion 22d. In this case, the outer surface of the base layer 22c is electrically connected to an external power source or power load. An example of a cover terminal 122 having no protrusion 22d is shown in FIG. 6. This embodiment is also included in the secondary battery of the present disclosure. Furthermore, the cover terminal 22 may have a plurality of protrusions 22d. This embodiment will be described later.

[0052] The cover terminal 22 functions as an electrode terminal and is therefore made of an electrically conductive material. In addition, the cover terminal 22 functions as a cover for the cylindrical portion 21 and is therefore made of a material with high water vapor barrier properties in order to prevent deterioration of the power generating element 10. A material with high water vapor barrier properties is, for example, a material with a water vapor permeability of 1.0×10 -4 g / m 2· Less than 24h. The material of the lid terminal 22 that satisfies these conditions is, for example, a metal. The metal that can be used for the lid terminal 22 is not particularly limited, but examples include Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, etc. The metal constituting the lid terminal 22 may be the same as the metal constituting the current collector 11, or may be different. The metal constituting the positive electrode lid terminal 22a is preferably Al. The material constituting the negative electrode lid terminal 22b is preferably Cu. In addition, the lid terminal 22 may be made of a material other than a metal for a portion other than the portion used for electrical connection. For example, an aluminum film integrated resin or a known resin may be used for the material of the portion not used for electrical connection.

[0053] Here, a predetermined insulation treatment may be performed from the viewpoint of suppressing a short circuit due to contact between the cover terminal 22 and the power generating element 10 and the cylindrical portion 21. For example, from the viewpoint of suppressing a short circuit due to contact between the cover terminal 22 and the power generating element 10, an insulating material such as an insulating sheet may be disposed between the cover terminal 22 and the power generating element 10 (electrode laminate). This suppresses electrical connection between the power generating element 10 and the cover terminal 22, and suppresses a short circuit in the secondary battery 100.

[0054] Also, from the viewpoint of suppressing a short circuit caused by contact between the lid terminal 22 and the tubular portion 21, a metal laminate film in which at least the inner surface of the tubular portion 21 is covered with an insulating resin may be used. This makes it possible to suppress electrical connection between the lid terminal 22 and the tubular portion 21 without the need to dispose an insulating material on the lid terminal 22, and suppress a short circuit of the secondary battery 100. Also, in order to suppress a short circuit caused by contact with the tubular portion 21, the outer periphery of the lid terminal 22 (the outer periphery of the base layer 22c and the step portion 22g) may be wrapped with an insulating film, an insulating tape may be applied to the outer periphery of the lid terminal 22, or an insulating surface treatment may be performed. In this way, an insulating treatment may be performed to dispose a predetermined insulating layer on the outer periphery of the lid terminal 22. Also, an insulating treatment may be performed to dispose a predetermined insulating layer on the parts of the lid terminal 22 other than the faces 22e and 22f.

[0055] The length L1 of the base layer 22c of the cover terminal 22 is not particularly limited, and may be sufficient to provide sufficient water vapor barrier properties when the cylindrical portion 21 and the cover terminal 22 are integrated with the first resin 23. For example, it may be 0.2 mm or more, 0.5 mm or more, 3 mm or less, or 2 mm or less. The length L2 of the protruding portion 22d of the cover terminal 22 is not particularly limited, and may be sufficient to provide sufficient water vapor barrier properties when the cylindrical portion 21 and the cover terminal 22 are integrated with the first resin 23 by disposing the first resin 23 on the outer periphery of the protruding portion 22d as shown in FIG. 2. For example, it may be 0.5 mm or more, 1 mm or more, 3 mm or less, or 2 mm or less.

[0056] In conventional laminated batteries, the electrode terminals are arranged so as to protrude outward. Since the electrode terminals are usually made of thin metal, the surface arranged in the thickness direction of the electrode terminal is used for connection with external members. On the other hand, the surface 22f of the cover terminal 22 arranged in the length direction is used for connection with external members. In a sense, the surface 22f of the cover terminal 22 can be said to be a terminal in which the direction of a conventional electrode terminal is changed by 90°. In this way, the cover terminal 22 has the surface 22f arranged in the length direction, which makes it easier to connect with external members.

[0057] The cover terminal 22 is electrically connected to the current collector 11 of the power generating element 10, but the connection method is not particularly limited. For example, the surface 22e of the cover terminal 22 and the current collector 11 may be joined by a known joining method such as pressure bonding by pressing, laser bonding, ultrasonic bonding, and bonding using a conductive material. Also, as shown in FIG. 2, the current collector 11 may be electrically connected to the cover terminal 22 in a state where it is curved in one direction. In this way, the structural efficiency can be improved by electrically connecting the current collector 11 to the cover terminal 22 in a curved state. This will be described in detail below. Also, when the current collector 11 is in a curved state, a force acts on the current collector 11 in a direction that releases the curve. Therefore, by arranging the cover terminal 22 in a direction that releases the curve of the current collector 11, the current collector 11 is pressed against the cover terminal, and the connection between the current collector 11 and the cover terminal 22 can be strengthened.

[0058] The cover terminal 22 may have a protruding portion 22h protruding inward from an end of the inner surface 22e of the base material layer 22c. The protruding portion 22h may be disposed at at least one end (thickness direction and / or width direction) of the surface 22e, or may be disposed at a plurality of ends. Preferably, the protruding portion 22h is disposed at each of the opposing ends of the surface 22e, more preferably, the protruding portion 22h is disposed at each end in the thickness direction and width direction of the surface 22e, and even more preferably, the protruding portion 22h is disposed on the entire outer periphery of the surface 22e. FIG. 7 shows an example of a cover terminal 222 in which the protruding portion 22h is disposed at both ends in the thickness direction of the surface 22e. FIG. 7(a) is a side view of the cover terminal 222, and FIG. 7(b) is an example of the use of the cover terminal 222. In this way, the cover terminal 222 has the protruding portion 22h, which increases the contact area with the first resin 23 and improves the adhesion with the cylindrical portion 21. Furthermore, cover terminal 222 can effectively utilize the space surrounded by surface 22e and protruding portion 22h, thereby improving the structural efficiency of battery 100. Length L3 of protruding portion 22h is not particularly limited, and may be, for example, 0.5 mm or more, 1 mm or more, 3 mm or less, or 2 mm or less.

[0059] 2, the cover terminal 22 is used as an inner cover terminal disposed inside the opening 21a of the cylindrical portion 21, but the cover terminal of the present disclosure is not limited thereto, and may be an outer cover terminal disposed outside the opening 21a of the cylindrical portion 21 so as to cover it. From the viewpoint of improving structural efficiency, the cover terminal 22 may be an inner cover terminal.

[0060] The width or thickness of the cover terminal 22 may be equal to or less than the width or thickness of the power-generating element 10. The width or thickness of the cover terminal 22 is the maximum value of the width or thickness of the cover terminal 22, and is typically the width or thickness of the base layer 22c of the cover terminal 22.

[0061] First, the width of the cover terminal 22 will be described. The width of the cover terminal 22 may be equal to or smaller than the width of the power generating element 10. In other words, the width of the power generating element 10 is equal to or larger than the width of the cover terminal 22. This allows unnecessary space to be eliminated, and structural efficiency to be improved. Similarly, the thickness of the cover terminal 22 may be equal to or smaller than the thickness of the power generating element 10. In other words, the thickness of the power generating element 10 is equal to or larger than the thickness of the cover terminal 22. This allows unnecessary space to be eliminated, and structural efficiency to be improved. The detailed relationship between the width and thickness of the power generating element 10, the cover terminal 22, and the tubular portion 21 is as described above.

[0062] (First resin 23) The first resin 23 is disposed between the cylindrical portion 21 and the cover terminal 22, and integrates the cylindrical portion 21 and the cover terminal 22. Since the cylindrical portion 21 and the inner cover terminal 22 are thus integrated by the first resin 23, the secondary battery 100 can ensure sufficient water vapor barrier properties. In addition, the first resin 23 may be used as an insulating member when the cover terminal 22 is connected to an external member.

[0063] As shown in FIG. 2, the first resin 23 fills the gap between the cylindrical portion 21 and the cover terminal 22. The "gap between the cylindrical portion 21 and the cover terminal 22" refers to the gap between the inner surface of the cylindrical portion 21 and the outer periphery of the cover terminal 22. In order to form such a gap, the cover terminal 22 may be made one size smaller than the outer shape of the cylindrical portion 21. For example, the gap may be 0.01 mm to 3 mm, and may be set in the range of 0.05 mm to 0.5 mm. As described above, the first resin 23 is disposed in the gap, and thus the cylindrical portion 21 and the cover terminal 22 are integrated by the first resin 23. Here, the first resin 23 may fill at least a part of the gap between the cylindrical portion 21 and the cover terminal 22, but from the viewpoint of ensuring the water vapor barrier property, it is preferable to fill the entire gap as shown in FIG. 2. However, as described below, when filling the inside of the tubular portion 21 with the second resin 24, the second resin 24 may be placed in the gap formed between the tubular portion 21 and the cover terminal 22 in addition to the first resin 23.

[0064] In addition, when the cover terminal 22 has a protruding portion 22d, the first resin 23 may be disposed between the tubular portion 21 and the cover terminal 22 and on at least a part of the outer peripheral surface of the protruding portion 22d. As shown in FIG. 2, the first resin 23 is disposed on the entire outer peripheral surface of the protruding portion 22d, and the step portion 22g formed by the base layer 22c and the protruding portion 22d is filled with the first resin 23. That is, the first resin 23 may be disposed so as to fill the step portion 22g. At this time, the surface of the first resin 23 on the opening 21a side may be disposed so as to be flat with the surface 22f of the cover terminal 22. In this way, by filling the step portion 22g formed by the material layer 22c and the protruding portion 22d with the first resin 23, the water vapor barrier property can be improved.

[0065] In this way, the exterior part 20 fills the paths (gaps) through which water vapor invades from the outside to the inside with the first resin 23, and therefore can adequately suppress the intrusion of water vapor into the interior of the exterior part 20. In other words, this means that the exterior part 20 may have gaps between the tubular part 21 and the cover terminal 22 through which water vapor can invade. Because such gaps are filled with the first resin 23, the tubular part 21 and the cover terminal 22 do not need to be designed strictly.

[0066] Here, "integration" means that each material is bonded by resin and integrated to the extent that it can be recognized as one member. "Integration" using the first resin 23 can be achieved by placing the cylindrical portion 21 housing the power generating element 10 therein and an intermediate member having the cover terminal 22 disposed in the opening 21a of the cylindrical portion 21 in a predetermined mold, and injecting the first resin into the mold and allowing it to harden. In this manner, the exterior body 20 can be manufactured by integral molding using the first resin 23.

[0067] In this way, the secondary battery 100 seals the power generating element 10 using the exterior part 20 instead of the conventional laminate exterior body, and thus has water vapor barrier properties equal to or better than those of the conventional laminate exterior body. Furthermore, with the conventional laminate exterior body, sealing defects may occur when the end of the power generating element is heat-sealed after the power generating element is housed inside. In such a case, water vapor may enter through the defective sealing area, and water vapor barrier properties cannot be guaranteed. In contrast, the secondary battery 100 seals the power generating element 10 inside the exterior part 20 using the first resin 23, and therefore sealing defects are very unlikely to occur. Therefore, it is not necessary to carry out a water vapor barrier property inspection (leak inspection) after the secondary battery 100 is manufactured.

[0068] From the viewpoint of preventing deterioration of the power generating element, a resin having water vapor barrier properties is used as the first resin 23. The resin having water vapor barrier properties is, for example, a resin having a water vapor permeability of 1.0×10 -4 g / m 2 24 hours or more 50 x 10 -4 g / m 2 Resins having a shelf life of 24 hours or less. The type of such resin is not particularly limited, but examples thereof include thermoplastic resins. The thermoplastic resin is not particularly limited, but examples thereof include polypropylene and polyester.

[0069] <Structural efficiency> Next, the structural efficiency of the secondary battery 100 will be described. Figures 8 and 9 show a comparison between a conventional laminated battery and the secondary battery 100. Figure 8 is a comparison of longitudinal cross-sectional views of the conventional laminated battery (a) and the secondary battery 100 (b). Figure 9 is a comparison of plan views of the conventional laminated battery (a) and the secondary battery 100 (b).

[0070] As shown in Figure 8(a), a conventional laminated battery has a terminal portion (region A) protruding from the laminated outer casing, a heat-welded portion (region B) where the laminated outer casing is heat-welded, a joint portion (region C) where the electrode terminal and the current collector are joined, and a current collector portion (region D) where there are multiple current collectors connected to the power generating element.

[0071] 8(b), the use of the exterior part 20 in the secondary battery 100 allows the lengths of all areas to be shorter than those of a conventional laminated battery.

[0072] First, the reason why the length of the portion corresponding to region A is short will be described. Since the secondary battery 100 uses the cover terminal 22, the terminal portion (surface 22f) is perpendicular to the length direction. Therefore, the secondary battery 100 does not have a portion corresponding to region A. Also, depending on the form of the first resin 23 arranged on the step portion 22g of the cover terminal 22, the convex portion 22d of the cover terminal 22 may be arranged to protrude beyond the first resin 23. Even in such a case, the portion corresponding to region A can be made infinitesimally shorter than that of a conventional laminated type battery.

[0073] Next, the reason why the length of the portion corresponding to region B is short will be explained. Region B (seal width) of a conventional laminated battery must usually be set to a length exceeding 3 mm. This is for the following reasons. (1) If the seal width is short, proper heat welding cannot be performed, and there is a possibility that poor sealing will result. (2) Since the laminated exterior body does not have high rigidity, if the seal width is short, the adhesion of the seal area may peel off due to an external impact, and the adhesive surface may not be maintained. (3) If the terminal is not parallel to the adhesive surface of the laminated exterior body during heat welding, the correction force to return the inclination to the original state is weak if the seal width is short, so that proper heat welding cannot be performed and the probability of poor sealing increases. (4) If the seal width is short during heat welding, the pressure per area applied to the seal area by the heat welding head becomes large, and there is a risk that the metal layer inside the laminated exterior body will cross the insulating layer and bite into the terminal. If the metal layer bites into the terminal, it is undesirable because it causes a short circuit.

[0074] On the other hand, the secondary battery 100 uses an exterior part 20 in which the cylindrical part 21 and the lid terminal 22 are integrated with the first resin 23. In this way, by integrating with the first resin 23, it is possible to highly suppress poor adhesion between the cylindrical part 21 and the lid terminal 22. In addition, even if the lid terminal 22 is tilted and the gap between the cylindrical part 21 and the lid terminal 22 is not parallel, they can be properly bonded. Furthermore, since no thermal welding is performed, short circuits hardly occur. In addition, since the rigidity is ensured by integrating with the first resin 23, peeling of the adhesive part is also suppressed. Therefore, the length (L1+L2) of the part corresponding to the region B of the conventional laminated battery can be set to 3 mm or less in the secondary battery 100. It may also be 2 mm or less, 0.5 mm or more, or 1 mm or more. Therefore, the length of the part corresponding to the region B of the secondary battery 100 can be shorter than that of the conventional laminated battery.

[0075] Next, the reason why the length of the portion corresponding to region C is shortened will be explained. As shown in Fig. 8(b), since surface 22e of lid terminal 22 of secondary battery 100 is perpendicular to the longitudinal direction, current collector foil 11 is joined to surface 22e of lid terminal 22 in a curved state. Therefore, the length of the joined portion is very short. Therefore, the length of the portion corresponding to region C of secondary battery 100 can be shortened compared to conventional laminated batteries.

[0076] Finally, the reason why the length of the portion corresponding to region D is shortened will be explained. As described above, current collector foil 11 is joined to surface 22e of cover terminal 22 in a curved state. Therefore, the length of the portion where current collector 11 is present is also very short. Therefore, the secondary battery 100 can have a shorter length of the portion corresponding to region D than a conventional laminated battery.

[0077] Next, FIG. 9 will be described. As shown in FIG. 9, a conventional laminated battery requires heat-sealed parts S on a maximum of four sides of the outer periphery. In contrast, both ends in the length direction of the secondary battery 100 are structurally efficient by the exterior parts 20, as described above. In addition, since the secondary battery 100 uses the cylindrical part 21, which is a cylindrical metal body, heat-sealed parts are not required on both sides in the width direction. Therefore, the secondary battery 100 has structural efficiency in this respect. In addition, the absence of heat-sealed parts on both sides in the width direction also improves the water vapor barrier property.

[0078] Here, the advantages of the secondary battery 100 over the laminated battery using a lid as described in Patent Documents 2 and 3 will be described. Even in the case of a laminated battery using a lid, the lengths of the regions A and D are equivalent to those of a conventional laminated battery. The length of the region B is also equivalent to that of a conventional laminated battery (seal width: length exceeding 3 mm). This is almost the same as the reason for the conventional laminated battery, but specifically, it is as follows. (1) If the seal width is short, the seal may be defective. (2) Since the laminated exterior body does not have high rigidity, if the seal width is short, the adhesion of the seal area may peel off due to an external impact, and the adhesive surface may not be maintained. (3) Also, when the lid is tilted due to an external impact, the corrective force for returning the tilt to its original state is weak, so the adhesive surface may not be properly maintained. (4) During thermal welding, if the outer peripheral surface of the lid is not parallel to the welded surface of the laminated exterior body, the corrective force to return the inclination to its original state is weaker if the seal width is short, and the probability of poor sealing increases. Furthermore, the length of region C, although it depends on the shape of the lid, is equivalent to the length of a conventional laminated battery. In addition, when the laminated exterior body is formed into a cylindrical shape, a sealing region may be required on the side. For these reasons, the secondary battery 100 has improved structural efficiency compared to a laminated battery having a lid.

[0079] As described above, the secondary battery 100 can achieve a significant improvement in structural efficiency compared to conventional laminate-type batteries.

[0080] <Prevention of Short Circuit Between Power-Generating Element 10 and Exterior Part 20> When the cylindrical portion 21 and the cover terminal 22 are made of metal, from the viewpoint of suppressing a short circuit due to contact between the power generating element 10 and these members, as described above, an insulating material may be disposed between the power generating element 10 and these members. Specific forms for disposing the insulating material will be described below.

[0081] First, a description will be given of a secondary battery 101 in which the inside of the exterior part 20 is filled with the second resin 24. A longitudinal cross-sectional view of a secondary battery 101 in which the entire inside of the exterior part 20 is filled with the second resin 24 is shown in FIG.

[0082] As shown in Fig. 10, the exterior part 20 has a second resin 24 filled therein. The second resin 24 can be the same resin as the first resin 23. In Fig. 10, the second resin 24 is disposed throughout the interior of the exterior part 20, but this is not limited thereto, and it is sufficient that the second resin 24 is disposed in a position where the power generating element 10 and the exterior part 20 can come into contact with each other. Preferably, the second resin 24 is disposed throughout the interior of the exterior part 20.

[0083] In this way, by providing the exterior part 20 with the second resin 24 inside, the cylindrical part 21, the cover terminal 22, and the power generating element 10 can be integrated with the second resin 24. This makes it possible to suppress a short circuit caused by contact between the power generating element 10 and the exterior part 20. For example, even if a predetermined insulating layer is arranged on the power generating element 10 or the exterior part 20, there is a risk that the insulating layer will be broken by an external impact, causing the power generating element 10 and the exterior part 20 to come into contact with each other and cause a short circuit. In contrast, by arranging the second resin 24 inside the exterior part 20, it is possible to suppress contact between the power generating element 10 and the exterior part 20 more effectively than when only an insulating layer is arranged, and it is possible to suppress a short circuit in the battery.

[0084] In addition, the secondary battery 100 has the second resin 24, which further improves the water vapor barrier property. Furthermore, by integrating the various members with the second resin 24, the external Since the movement of the power generating element 10 due to the impact can be suppressed, the movement of the power generating element 10 can be prevented. This can prevent the current collector 11 from being broken. In addition, it can prevent the power generating element 10 from being chipped due to an external impact. It is also possible to prevent slipping and falling.

[0085] The method of filling the second resin 24 inside the exterior part 20 is not particularly limited, but for example, a hole for injecting the second resin 24 may be provided at a predetermined position of the cylindrical part 21. The shape of the hole is not particularly limited, and may be circular, elliptical, or rectangular. At least one hole may be provided in the cylindrical part 21. For example, as shown in FIG. 3(c), a plurality of holes 21c and 21d having different shapes may be provided on the side surface of the cylindrical part 21. At least one hole may be provided in the cover terminal 22. For example, as shown in FIG. 5(b), a plurality of holes 22i may be provided in the cover terminal 22. When a power generating element for a liquid battery is used as the power generating element 10, a predetermined electrolyte may be injected through the hole after the second resin 24 is filled.

[0086] Next, a secondary battery 102 in which the power generating element 10 is wrapped in a resin film 13 having insulating properties and water vapor barrier properties will be described. Fig. 11 shows a longitudinal cross-sectional view of the secondary battery 102 in which the power generating element 10 is wrapped in a resin film 12. Fig. 12 shows a plan view of the power generating element 10 wrapped in the resin film 12.

[0087] As shown in Figs. 11 and 12, the resin film 12 has a cylindrical shape and has an opening on the side where the cover terminals 22 are arranged. The resin film 12 encases the entire power generating element 10 (excluding the current collector 11, which is a tab). In Fig. 12, the members arranged inside the resin film 12 are indicated by dotted lines. By encasing the entire power generating element 10 in this manner with the resin film 12, it is possible to suppress a short circuit caused by contact between the power generating element 10 and the exterior part 20 (particularly the cylindrical part 21). Furthermore, by providing the secondary battery 100 with the resin film 12, the water vapor barrier property can be further improved.

[0088] The resin film 12 may be any resin film having insulating properties and water vapor barrier properties. For example, a resin film on which aluminum or silica is vapor-deposited can be used. The type of resin is not particularly limited, but examples thereof include polypropylene and polyethylene terephthalate.

[0089] Alternatively, the power generating element 10 may be wrapped in the resin film 12 and the inside of the exterior part 20 may be filled with the second resin 24 .

[0090] <Other forms of the cylindrical portion> From the viewpoint of structural efficiency, the cylindrical portion 21 may be a cylindrical metal body or a metal laminate film formed into a cylindrical shape, as shown in Fig. 3. A cylindrical metal body is preferable. However, such a cylindrical portion has a problem in that it is difficult to accommodate the power generating element 10 inside. Therefore, the following cylindrical portions 121 and 221, which can easily accommodate the power generating element 10, may be used.

[0091] First, the cylindrical part 121 will be described. FIG. 13(a) shows a plan view of the cylindrical part 121, and FIG. 13(b) shows a widthwise cross-sectional view of the cylindrical part 121. As shown in FIG. 13, the cylindrical part 121 is composed of two metal plates 121a and a third resin 121d. The metal plate 121a is a so-called U-shaped member having a bottom surface 121b and protruding parts 121c protruding in the same direction from opposing ends of the bottom surface 121b. As shown in FIG. 13(b), the two metal plates 121a are stacked upside down, and the protruding parts 121c of the two metal plates 121a are stacked on each of the opposing side surfaces (side surfaces in the width direction) of the cylindrical part 121. The third resin 121c is arranged so as to cover each side surface of the cylindrical part 121. Specifically, the third resin 121c entirely covers the side surfaces of the protruding portions 121c of the overlapping metal plates 121a and fills the gaps between the protruding portions 121c of the overlapping metal plates 121a, so that the ends of the overlapping metal plates 121a are integrated with the third resin 121c.

[0092] Since the cylindrical portion 121 includes two metal plates 121a, the power generating element 10 is placed inside one of the metal plates 121a, and then the other metal plate 121a is placed upside down and the protruding portion 121c of the metal plate 121a is integrated with the third resin 121d to produce the cylindrical portion 121. In this manner, by using the cylindrical portion 121, the power generating element 10 can be easily accommodated inside the cylindrical portion 121.

[0093] Next, the cylindrical part 221 will be described. FIG. 14(a) shows a plan view of the cylindrical part 221, and FIG. 14(b) shows a widthwise cross-sectional view of the cylindrical part 221. As shown in FIG. 14, the cylindrical part 221 is composed of one metal plate 221a and a third resin 221d. The metal plate 221a is formed into a cylindrical shape, and the end 221b of the metal plate 221a is overlapped on one side surface of the cylindrical part 221. The third resin 221c is arranged so as to cover the side surface where the end 221b is overlapped. Specifically, the third resin 221c entirely covers the side surface side of the overlapping end 221b, and fills the gap of the end 221b of the overlapping metal plate 221a. As a result, the end 221b of the overlapping metal plate 221a is integrated with the third resin 221c.

[0094] Since the cylindrical portion 221 is made of one metal plate 121a, the power generating element 10 is placed inside the cylindrical metal plate 221a, and then the end portion 221b is integrated with the third resin 121c to produce the cylindrical portion 221. In this manner, by using the cylindrical portion 221, the power generating element 10 can be easily accommodated inside the cylindrical portion 221. Also, as shown in FIG. 15, the secondary battery can be easily cooled by contacting the side of the cylindrical portion 221 on which the third resin 221c is not placed with a predetermined cooling portion X. Note that such a cooling mode can also be applied to a secondary battery using the cylindrical portion 21.

[0095] The metal plate used in the above two embodiments may be a simple metal plate or a metal laminate film. In the illustrated embodiment, a metal plate is used. The type of metal may be a metal having high water vapor barrier properties. The third resin used in the above two embodiments may be the same resin as the first resin 23. In addition, "integration" by the third resin is possible by placing the overlapped metal plates 121a or the metal plate 221a molded into a cylindrical shape in a predetermined mold and injecting the third resin into the mold and hardening it. This makes it possible to manufacture the cylindrical parts 121 and 221.

[0096] <Other forms of cover terminal> From the viewpoint of further improving the structural efficiency of the secondary battery 100, a lid terminal 322 having a slit portion 322j may be used instead of the lid terminal 22. A secondary battery 103 having a lid terminal 322 having a slit portion 322j will be described below.

[0097] Fig. 16 shows a perspective view of the secondary battery 103. Fig. 17(a) shows a longitudinal cross-sectional view taken along line XVIIa-XVIIa in Fig. 16, (b) shows a longitudinal cross-sectional view taken along line XVIIb-XVIIb in Fig. 16, and (c) shows a longitudinal cross-sectional view taken along line XVIIc-XVIIc in Fig. 16. Fig. 18(a) shows a perspective view of the cover terminal 322, (b) shows a front view of the cover terminal 322 observed from the direction b in (a), and (c) shows a rear view of the cover terminal 22 observed from the direction c in (a).

[0098] The secondary battery 103 differs from the secondary battery 100 mainly in the following respects. That is, the power generating element 310 has a plurality of current collectors 311, the inner surface 322e of the cover terminal 322 has a plurality of slits 322j, and the current collectors 311 are arranged in the slits 322j, thereby electrically connecting the current collectors 311 and the cover terminal 322. By adopting such a configuration, the distance between the power generating element 310 (electrode laminate) and the cover terminal 322 can be shortened, and the structural efficiency can be further improved. The detailed effects will be described later.

[0099] The shape of the power generating element 310 is such that the curved current collector 11 of the power generating element 10 described above is changed to a straight current collector 311. This allows the current collector 311 to be inserted and arranged in the slit portion 322j, as shown in the dotted line frame in FIG. 17(a). Here, in FIG. 17(a), the power generating element 310 has multiple current collectors 311. However, the secondary battery of the present disclosure is not limited to this, and at least one current collector 311 may be used.

[0100] The cover terminal 322 has a base material layer 322c and a protrusion 322d arranged at each end of the base material layer 322c in the width direction. The protrusion 322d has a substantially circular recess 322k to facilitate connection with an external member. The recess 322k may be, for example, a screw hole for connection with an external member, a straight hole for positioning, or a straight hole for connection such as a press-fit rivet. As shown in FIG. 17(a) and FIG. 18(c), the inner surface 322e of the base material layer 322c of the cover terminal 322 has a plurality of slits 322j. The current collector 311 is arranged in the slits 322j, so that the current collector 311 and the cover terminal 322 are electrically connected to each other.

[0101] In the secondary battery 103, a cover terminal 322 having two protrusions 322d is used, but the shape of the cover terminal is not limited to this, and it is sufficient that the inner surface 322e of the cover terminal 322 has a slit portion 322j, and the shape of the outside is not particularly limited. In addition, in the secondary battery 103, a cover terminal 322 having a plurality of slit portions 322j is used, but the number of slit portions may be at least one.

[0102] Slit portion 322j penetrates cover terminal 322 in the length direction, and current collector 311 is disposed inside slit portion 322j. However, slit portion 322j does not have to penetrate. Whether slit portion 322j penetrates can be appropriately set depending on the joining method with current collector 311.

[0103] The current collector 311 may be inserted from the inner surface 322e of the cover terminal 322, or from the side (surface in the thickness direction or width direction). That is, the base layer 322c of the cover terminal 322 may have an opening 1 of the slit portion 322 on the side as well. The thickness of the slit portion 322i is not particularly limited, but may be a thickness that allows the current collector foil 311 to be placed. For example, it is 0.1 μm or more and 1 mm or less. The slit portion 322j has an opening 322l for inserting the current collector 311, and the opening 322l may have a shape (for example, a V-shape) that is wider in the thickness direction than the inside in order to facilitate the insertion of the current collector 311. The area surrounded by the dotted line in FIG. 17(a) shows the state in which the current collector 311 is inserted from the inner surface 322e of the cover terminal 322.

[0104] Moreover, Fig. 19 shows a front view and a plan view of a cover terminal having a slit portion for inserting a current collector 311 from the side. Fig. 19(a) is an example of a cover terminal having two convex portions. Fig. 19(b) is an example of a cover terminal having one convex portion. As shown in (a), it is technically possible to provide a slit portion on the back side of the convex portion, but this tends to be difficult. Therefore, as shown in (b), it is common to provide the convex portion only in a position that does not overlap the slit portion.

[0105] When the cover terminal 322 has slits 322j penetrating in the length direction, the first resin 323 may be arranged to cover the entire outer opening of each slit 322j. For example, as shown in FIG. 16, the first resin 323 may be arranged to cover the entire outer surface of the base layer 322c. This makes it possible to prevent outside air (water vapor) from entering the exterior part 320 from the slits 322j. The first resin 323 may enter the slits 322j, and at least a part of the inside may be filled with the first resin 323.

[0106] The connection form between the current collector 311 and the cover terminal 322 is not particularly limited, and it is sufficient that the current collector 311 is simply arranged in the slit portion 322j. However, from the viewpoint of strengthening the connection between the current collector 311 and the cover terminal 322, the slit portion 311i (cover terminal 322) and the current collector 311 may be joined in a state in which the current collector 311 is arranged in the slit portion 322j. The joining method is not particularly limited, and a known joining method such as pressure bonding by pressing, laser joining, ultrasonic joining, and conductive material fixing method can be adopted. When the slit portion 322j is penetrating, the laser joining or the conductive material fixing method may be adopted. When the slit portion 322j is not penetrating, the press processing or ultrasonic processing may be adopted.

[0107] Here, the slit portion 322j will be further described. FIG. 17(a) shows a configuration in which one current collector is arranged in one slit portion 322j. By adopting such a configuration, the distance between the power generating element 310 (electrode laminate) and the cover terminal 322 can be reduced. It is also possible to make the distance between the power generating element 310 (electrode laminate) and the cover terminal 322 almost zero or zero (see FIG. 17(a)). On the other hand, depending on the shape of the cover terminal 322, it may be difficult to arrange one current collector in one slit portion 322j. Therefore, two or more current collectors may be arranged in one slit portion 322j. For example, two current collectors may be arranged in one slit portion 322j, three current collectors may be arranged, or four current collectors may be arranged. However, the more current collectors 311 arranged in one slit portion 322j, the longer the distance between the power generating element 310 and the cover terminal 322 may be. Therefore, the number of current collectors arranged in one slit portion 322j may be ten or less, or eight or less.

[0108] Fig. 20 shows an example in which two current collectors 311 are arranged in one slit portion 322j. As shown in Fig. 20, when two current collectors 311 are arranged in one slit portion 322j, an area is required in which the two current collectors 311 are overlapped. This area tends to become longer as the number of overlapping current collectors 311 increases. Therefore, from the viewpoint of improving structural efficiency, the fewer the number of current collectors 311 arranged in one slit portion 322j, the better, and a configuration in which one current collector 311 is arranged in one slit portion 322j is the best.

[0109] The distance between the cover terminal 322 and the power generating element 310 (electrode laminate) is not particularly limited, and the closer the distance, the more efficient the structure, but may be, for example, 2 mm or less, 0.5 mm or less, or 0 mm, i.e., the cover terminal 322 and the power generating element 310 may be in contact. However, if the cover terminal 322 and the power generating element 310 are in contact, a predetermined insulation treatment must be applied to at least one of the cover terminal 322 and the power generating element 310.

[0110] 18(c) shows a configuration in which the slit portions 322j are arranged side by side in the thickness direction. This is because the current collectors 311 of the power generating element 310 are arranged side by side in the thickness direction. In this manner, the arrangement direction of the slit portions 322j can be set along the arrangement direction of the current collectors 311 of the power generating element 310. Therefore, in the secondary battery of the present disclosure, the arrangement direction of the slit portions is not limited to the thickness direction, and can be set appropriately depending on the arrangement direction of the current collectors of the power generating element.

[0111] 18(c), the slit portion 322j is disposed at the center of the inner surface 322e of the base layer 322c in order to avoid the recessed portion 322k of the protruding portion 322d. Therefore, in the secondary battery of the present disclosure, the position of the slit portion is not particularly limited and can be appropriately set according to the shape of the cover terminal, etc.

[0112] As described above, by using the cover terminal 322 having the slit portion 322j, the distance between the cover terminal 322 and the power generating element 310 (electrode laminate) can be set short. On the other hand, if the distance between the cover terminal 322 and the power generating element 310 (electrode laminate) becomes too short, a problem of short circuit due to contact occurs. Therefore, the cover terminal 322 may be subjected to a predetermined insulation treatment.

[0113] The insulation treatment for the cover terminal 322 is not particularly limited, and for example, the outer periphery of the cover terminal 322 may be wrapped with an insulating film, an insulating tape may be applied to the outer periphery of the cover terminal 322, or an insulating sheet may be disposed on the outer periphery of the cover terminal 322. In this manner, insulation treatment may be performed by disposing a predetermined insulating layer on the outer periphery of the cover terminal 322. In particular, from the viewpoint of suppressing a short circuit due to contact between the power generating element 10 and the cover terminal 322, an insulating sheet may be disposed between the power generating element 310 (electrode laminate) and the cover terminal 322. Examples of the insulating sheet include polyethylene terephthalate (PET), polyolefins (PO) such as polyethylene (PE) and polypropylene (PP), and insulating resins such as fluororesins.

[0114] FIG. 21(a) shows a form in which an insulating sheet 325 is disposed between the power generating element 10 and the cover terminal 322. The current collector 311 is disposed in the slit portion 322j, and therefore the insulating sheet 325 has a slit 325a through which the current collector 311 passes. The slit 325a of the insulating sheet 325 also functions as a guide for inserting the current collector 311 into the slit portion 322j. The position and number of the slits 325a are set according to the position and number of the slit portion 322j. As shown in the dotted line portion of FIG. 21(a), the slit 325 has an opening 325a for inserting the current collector 311, and in order to facilitate the insertion of the current collector 311, the opening 325a may have a shape (for example, a V-shape) that is wider in the thickness direction than the inside. When the current collector 311 is inserted from the side of the cover terminal 322, an opening is also disposed on the side of the insulating sheet 325.

[0115] FIG. 21(b) shows an example of the arrangement of the insulating sheet 325 when two current collectors 311 are arranged in one slit portion 322j. In this way, even when two or more current collectors 311 are arranged in one slit portion 322j, the insulating sheet 325 can be arranged between the power generating element 10 and the cover terminal 322. Here, when the opening 325a of the slit 325a of the insulating sheet 325 has a wide shape in the thickness direction, it is also possible to arrange the area where the current collectors 311 are overlapped inside the opening 325a. Therefore, even when two or more current collectors 311 are arranged in one slit portion 322j, the distance between the insulating sheet 325 and the power generating element 310 (electrode laminate) can be shortened. FIG. 21(c) shows an example of the arrangement of the insulating sheet 325 when two current collectors 311 are arranged in one slit portion 322j and the opening 325a of the slit 325a of the insulating sheet 325 has a wide shape in the thickness direction. As shown in FIG. 21( c ), the power generating element 310 (electrode stack) can be placed in a position that is almost in contact with or in contact with the insulating sheet 325 .

[0116] In order to insulate the power generating element 10 from the tubular portion 321, the insulating sheet 325 may be disposed between a surface of the power generating element 310 in the width direction or thickness direction and an inner surface of the tubular portion 321 in the width direction or thickness direction, or may be disposed between a surface of the power generating element 310 in the width direction or thickness direction and an inner surface of the tubular portion 321 in the width direction or thickness direction. As an example, Fig. 21 shows an example of an embodiment in which the insulating sheet 325 is disposed between a surface of the power generating element 310 in the thickness direction and an inner surface of the tubular portion 321 in the thickness direction.

[0117] (Structural efficiency improvement) The structural efficiency of the secondary battery 103 will be described. Fig. 23 corresponds to Fig. 8, and a longitudinal cross-sectional view of the secondary battery 103 is added in (c), and a comparison is made between the longitudinal cross-sectional views of a conventional laminated battery (a), a secondary battery 100 (b), and a secondary battery 103 (c). Note that a current collector is shown in the secondary battery 103 shown in (c) to facilitate comparison.

[0118] The results of the comparison between the laminated battery (a) and the secondary battery 100(b) are as described above. Here, the secondary battery 100(b) and the secondary battery 103(c) are compared. As can be seen from FIG. 23, the area D of the secondary battery 103 is shorter than that of the secondary battery 100. The reason for this is that in the secondary battery 100, the current collector 11 is joined to the cover terminal 22 in a curved state, whereas in the secondary battery 103, the current collector 311 is disposed in the slit portion 322j of the cover terminal 332, which further shortens the distance between the cover terminal 322 and the power generating element 310. Therefore, the secondary battery 103 can further improve the structural efficiency. In addition, with this improved structural efficiency, the presence of excess space inside the exterior portion 320 can be suppressed, and the rigidity of the secondary battery 103 can be improved.

[0119] (Resin filling inside) In the case where the second resin 324 is filled in the secondary battery 103, the second resin 324 may be disposed over the entire inside of the exterior part 320, but since resin has the property of diffusing water vapor inside, albeit in small amounts, there is a risk that water vapor from the outside will diffuse inside the first resin and the second resin and reach the end face of the power generating element. Specifically, as shown in Fig. 24, there is a risk that water vapor will reach the longitudinal face of the power generating element 310 (electrode laminate) that is closest to the first resin.

[0120] Therefore, in consideration of the water vapor diffusion inside the resin, it is better that the second resin 324 is not disposed between the cover terminal 322 and the power generating element 310. In other words, the second resin 324 only needs to be disposed at a position where the power generating element 10 and the exterior part 20 can come into contact with each other. Specifically, the second resin 324 only needs to be disposed between the surface of the power generating element 310 in the width direction or thickness direction and the inner surface of the tubular part 321 in the width direction or thickness direction, and the second resin 324 only needs to be disposed between the surface of the power generating element 310 in the width direction or thickness direction and the inner surface of the tubular part 321 in the width direction or thickness direction. As an example, FIG. 25(a) shows an example of a configuration in which the second resin 324 is disposed between the surface of the power generating element 310 in the thickness direction and the inner surface of the exterior part in the thickness direction. The reason why such a configuration is possible is that, as described above, the secondary battery 103 can shorten the distance between the cover terminal 322 and the power generating element 310 (electrode laminate). Even in this configuration, the cylindrical portion 321, the cover terminal 322, and the power generating element 310 can be integrated with the second resin 324.

[0121] 25(b) shows an example of an embodiment in which an insulating sheet 325 is further disposed between the cover terminal 322 and the power generating element 310. By disposing the insulating sheet 325 in this manner, it is possible to further prevent water vapor diffusing inside the resin from penetrating into the power generating element 310 (electrode laminate).

[0122] Furthermore, by arranging second resin 324 only at positions where power generating element 310 and tubular portion 321 can come into contact with each other, current collector 311 can be prevented from being cut or broken when second resin 324 is filled.

[0123] The secondary battery of the present disclosure has been described above using the secondary batteries 100 to 103 as an embodiment. As described above, the secondary battery of the present disclosure can improve the structural efficiency. The secondary battery of the present disclosure can be used for any purpose. For example, the secondary battery of the present disclosure can be used as a secondary battery for vehicles. [Explanation of symbols]

[0124] 10, 310 Power generation element 11, 311 Current collector 11a Positive electrode current collector 11b Negative electrode current collector 12 Resin film 20, 320 Exterior part 21, 121, 221, 321 Cylindrical part 21a opening 21b Projection 21c hole 21d hole 22, 122, 222, 322 Lid terminal 22a Positive cover terminal 22b Negative lid terminal 22c, 322c base material layer 22d, 322d convex part 22e, 322e plane 22f side 22g Step 22h protrusion 22i hole 23, 323 Resin (First Resin) 24 Second Resin 100, 101, 102, 103 Secondary battery 121a, 221a metal plate 121b Bottom 121c Protrusion 121d, 221c Third resin 221b End 322j Slit section 322k recess 322l opening 325 Insulation Sheet 325a Slit

Claims

1. a power generating element and an exterior part that houses the power generating element therein; The exterior part is A cylindrical portion having openings on two opposing surfaces; a cover terminal disposed in each of the openings; a resin disposed between the cylindrical portion and the cover terminal, the cylindrical portion and the cover terminal are integrated with each other by the resin, the current collector of the power generating element and the cover terminal are electrically connected to each other, The power generating element has at least one of the current collectors, The inner surface of the cover terminal has at least one slit portion, The current collector is disposed in the slit portion, so that the current collector and the cover terminal are electrically connected to each other. Secondary battery.

2. a power generating element and an exterior part that houses the power generating element therein; The exterior part is A cylindrical portion having openings on two opposing surfaces; a cover terminal disposed in each of the openings; a resin disposed between the cylindrical portion and the cover terminal, the cylindrical portion and the cover terminal are integrated with each other by the resin, the current collector of the power generating element and the cover terminal are electrically connected, an insulating sheet having a slit through which at least one current collector is inserted is disposed between the power generating element and the cover terminal; Secondary battery.

3. a power generating element and an exterior part that houses the power generating element therein; The exterior part is A cylindrical portion having openings on two opposing surfaces; a cover terminal disposed in each of the openings; a resin disposed between the cylindrical portion and the cover terminal, the cylindrical portion and the cover terminal are integrated with each other by the resin, the current collector of the power generating element and the cover terminal are electrically connected, the cover terminal has a protrusion protruding outward from the cylindrical portion, The resin is disposed on at least a part of the outer circumferential surface of the protrusion. Secondary battery.

4. A power generating element and an exterior part that houses the power generating element therein, The exterior part is A cylindrical portion having openings on two opposing surfaces; a cover terminal disposed in each of the openings; a resin disposed between the cylindrical portion and the cover terminal, the cylindrical portion and the cover terminal are integrated with each other by the resin, the current collector of the power generating element and the cover terminal are electrically connected, The cover terminal has protrusions protruding inward from at least two or more ends of an inner surface of the cover terminal. Secondary battery.

5. A power generating element and an exterior part that houses the power generating element therein, The exterior part is A cylindrical portion having openings on two opposing surfaces; a cover terminal disposed in each of the openings; a resin disposed between the cylindrical portion and the cover terminal, the cylindrical portion and the cover terminal are integrated with each other by the resin, the current collector of the power generating element and the cover terminal are electrically connected, the cylindrical portion is made of a plurality of metal plates and a third resin, The metal plate has a protrusion protruding from an end portion, The metal plates are disposed so that the protrusions extend in a direction opposite to each other with a gap therebetween, The third resin is disposed so as to fill at least a part of the gap existing between the metal plates. Secondary battery.

6. A power generating element and an exterior part that houses the power generating element therein, The exterior part is A cylindrical portion having openings on two opposing surfaces; a cover terminal disposed in each of the openings; a resin disposed between the cylindrical portion and the cover terminal, the cylindrical portion and the cover terminal are integrated with each other by the resin, the current collector of the power generating element and the cover terminal are electrically connected, the cylindrical portion is made of a plurality of metal plates and a third resin, the metal plate is arranged to form the opening, The third resin is disposed so as to fill at least a part of the gap between the metal plates. Secondary battery.

7. A power generating element and an exterior part that houses the power generating element therein, The exterior part is A cylindrical portion having openings on two opposing surfaces; a cover terminal disposed in each of the openings; a resin disposed between the cylindrical portion and the cover terminal; the cylindrical portion and the cover terminal are integrated with each other by the resin, the current collector of the power generating element and the cover terminal are electrically connected, the cylindrical portion is made of one metal plate and a third resin, The metal plate is formed into a cylindrical shape, The ends of the metal plates are overlapped on one side surface of the cylindrical portion, The third resin is disposed so as to fill at least a part of the gap between the metal plates. Secondary battery.

8. 8. The secondary battery according to claim 1, wherein the current collector is electrically connected to the cover terminal in a curved state.

9. the exterior portion has a second resin filled therein; the cylindrical portion, the cover terminal, and the power generating element are integrated with a second resin; The secondary battery according to any one of claims 1 to 7.

10. The cylindrical portion is a cylindrical metal body or a metal laminate film formed into a cylindrical shape. The secondary battery according to any one of claims 1 to 9.

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