Secondary battery

Abstract

To provide a secondary battery capable of improving structural efficiency.SOLUTION: A secondary battery includes a power generation element and an exterior part storing the power generation element therein, wherein the exterior part has a cylindrical part having openings in two opposite surfaces, a lid terminal arranged in each of the openings, and a resin arranged so as to be arranged between the cylindrical part and the lid terminal, the cylindrical part and the lid terminal are integrated with each other by the resin, and a current collector of the power generation element and the lid terminal are electrically connected to each other.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This application relates to a secondary battery.

Background Art

[0002] Batteries such as lithium-ion secondary batteries are widely used as portable power sources for personal computers and mobile terminals or power sources for vehicle drive. As an example of a battery, a laminate battery is known. The laminate battery has a structure in which a power generation element is sealed inside a laminate exterior formed by overlapping film-like laminate sheets. Further, in the laminate battery, terminals electrically joined to the power generation element are oppositely arranged in a state of protruding outward from the inside of the laminate exterior, and a seal region is formed by welding the edges of the opposed laminate exteriors. Thereby, the power generation element is sealed inside the laminate exterior. Further, the laminate battery includes a seal region formed by overlapping and welding laminate sheets outside the power generation element.

[0003] Conventionally, miniaturization of battery structures has been studied. For example, Patent Document 1 discloses a technique for miniaturizing a laminate battery by bending a seal region provided at its end. Patent Document 2 discloses a technique for miniaturizing a laminate battery using a lid by bending a seal region provided at its end. Patent Document 3 discloses a structure including an exterior material surrounding the outside of an electrode assembly and first and second covers for sealing the exterior material in a lithium polymer secondary battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Although the techniques of Patent Documents 1 to 3 enable miniaturization of a laminated battery, further improvement in the structural efficiency of a secondary battery has been desired.

[0006] A laminated battery can be miniaturized, for example, by shortening the width of a seal area (seal width) sandwiching an electrode terminal. Usually, however, the seal width needs to be set to a length exceeding 3 mm. This is due to the following reasons. (1) If the seal width is short, proper heat welding may not be possible, resulting in seal failure. (2) Since the laminated exterior body does not have high rigidity, if the seal width is short, the adhesion of the seal area may be peeled off by an external impact, and the adhesion surface may not be retained. In addition, in a laminated battery having a lid, when the lid is tilted by an external impact, if the seal width is short, the corrective force for returning the tilt becomes weak, so that the adhesion surface may not be properly maintained. (3) During heat welding, if the outer peripheral surface of the terminal or the lid is not parallel to the adhesion surface of the laminated exterior body, if the seal width is short, the corrective force for returning the tilt becomes weak, so that proper heat welding cannot be performed and the probability of seal failure increases further. (4) During heat welding, if the seal width is short, the pressure per area applied to the seal area by the heat welding head increases, and there is a risk that the metal layer inside the laminated exterior body bites into the terminal across the insulating layer. Biting of the metal layer into the terminal causes a short circuit, which is undesirable. For the above reasons, it has been difficult to shorten the seal width and miniaturize the laminated battery.

[0007] Therefore, an object of the present disclosure is to provide a secondary battery capable of improving structural efficiency.

Means for Solving the Problems

[0008] As one aspect for solving the above problems, the present disclosure provides a secondary battery including a power generation element and an exterior portion that houses the power generation element therein. The exterior portion has a cylindrical portion having openings on two opposing surfaces, lid terminals disposed at the respective openings, and a resin disposed between the cylindrical portion and the lid terminals. The cylindrical portion and the lid terminals are integrated with the resin, and a current collector of the power generation element and the lid terminals are electrically connected.

[0009] The above secondary battery may be in the following aspects. That is, the width or thickness of the lid terminal may be equal to or less than the width or thickness of the power generation element. The current collector may be electrically connected to the lid terminal in a curved state. The power generation element has at least one current collector, the inner surface of the lid terminal has at least one slit portion, and the current collector is disposed in the slit portion, whereby the current collector and the lid terminal may be electrically connected. An insulating sheet may be disposed between the power generation element and the lid terminal. The lid terminal has a convex portion protruding outward, and resin may be disposed on at least a part of the outer peripheral surface of the convex portion. The lid terminal may have a protruding portion protruding inward from an end portion of the inner surface of the lid terminal. The exterior portion has a second resin filled therein, and the cylindrical portion, the lid terminals, and the power generation element may be integrated with the second resin.

[0010] The cylindrical portion of the above secondary battery may be in the following aspects. That is, the cylindrical portion may be a cylindrical metal body or a metal laminate film formed into a cylindrical shape. Further, the cylindrical portion is composed of two metal plates and a third resin. The metal plates have a bottom surface and protruding portions protruding in the same direction from the ends of the bottom surface. The metal plates are stacked upside down, and on the opposing side surfaces of the cylindrical portion, the protruding portions are stacked. The third resin is disposed so as to cover the respective side surfaces of the cylindrical portion, and the ends of the overlapping metal plates may be integrated with the third resin. Furthermore, the cylindrical portion is composed of one metal plate and a third resin. The metal plate is formed into a cylindrical shape, and on one side surface of the cylindrical portion, the ends of the metal plate are stacked. The third resin is disposed so as to cover the side surface where the ends are stacked, and the ends of the overlapping metal plates may be integrated with the third resin.

Advantages of the Invention

[0011] According to the secondary battery of the present disclosure, the structural efficiency can be improved.

Brief Description of the Drawings

[0012]

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Embodiments for Carrying Out the Invention

[0013] The secondary battery of the present disclosure will be described using secondary batteries 100 to 103 which are one embodiment. A perspective view of the secondary battery 100 is shown in FIG. 1. A longitudinal sectional view taken along line II-II of FIG. 1 is shown in FIG. 2. Here, 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 in orthogonal relationships with each other.

[0014] The secondary battery 100 includes a power generation element 10 and an exterior part 20 that houses the power generation element 10 inside. The exterior part 20 has a cylindrical part 21 having opening parts 21a on two opposing surfaces, lid terminals 22 (a positive electrode lid terminal 22a and a negative electrode lid terminal 22b) arranged at the respective opening parts 21a, and a resin 23 (hereinafter sometimes referred to as the "first resin 23") arranged between the cylindrical part 21 and the lid terminals 22, and the cylindrical part 21 and the lid terminals 22 are integrated with the resin 23. Also, current collectors 11 (a positive electrode current collector 11a and a negative electrode current collector 11b) included in the power generation element 10 are electrically connected to the lid terminals 22.

[0015] <Power generation element 10> The power generation element 10 stacks a positive electrode current collector 11a, a positive electrode active material layer, an electrolyte layer, a negative electrode active material layer, and a negative electrode current collector 11b (hereinafter, these may be collectively referred to as "electrode elements"). The electrode elements are stacked in the thickness direction. The number of each electrode element to be stacked is not particularly limited. The power generation element 10 in FIG. 2 is in a form in which a plurality of these electrode elements are stacked. Also, these electrode elements may be stacked so as to be electrically in series, or may be stacked so as to be electrically in parallel.

[0016] The power generation element 10 in FIG. 2 has a sheet-like shape and is rectangular in plan view. However, the power generation element 10 is not particularly limited as long as it has a shape that can be accommodated inside the exterior portion 20. Also, as shown in FIG. 2, each current collector 11 of the power generation element 10 is electrically connected to each lid terminal 22 via a current collector tab. Specifically, the positive electrode current collector 11a is electrically connected to the positive electrode lid terminal 22a via the positive electrode current collector tab. The negative electrode current collector 11b is electrically connected to the negative electrode lid terminal 22b via the negative electrode current collector tab. However, each current collector 11 may be electrically connected to the lid terminal 22 without passing through the current collector tab.

[0017] As described above, the power generation element 10 has an electrode laminate in which electrode elements are stacked and a current collector tab extending from the electrode laminate. In this specification, when the power generation element 10 is described, it may mean the entire power generation element 10 including the electrode laminate and the current collector tab, or may mean only the electrode laminate. When the power generation element 10 means only the electrode laminate, it may be described as "power generation element 10 (electrode laminate)". Also, in this specification, the current collector tab (positive electrode current collector tab, negative electrode current collector tab) may be described and explained by referring to the current collector 11 (positive electrode current collector 11a, negative electrode current collector 11b).

[0018] In order to suppress a short circuit due to contact with the cylindrical portion 21, the power generation element 10 may be subjected to a predetermined insulation treatment. For example, the power generation element 10 may be wrapped with an insulating film, an insulating sheet may be disposed between the power generation element 10 and the cylindrical portion 21, or an insulating tape may be bonded to the inner surface of the power generation element 10 or the cylindrical portion 21. Thus, an insulation treatment may be performed to dispose a predetermined insulating layer on the outer peripheral portion of the power generation element 10.

[0019] In the thickness direction, the power generation element 10 and the cylindrical portion 21 may be in contact with each other as long as either of them is subjected to an insulation treatment. In this case, the thickness of the lid terminal 22 may be made thinner by the thickness of the first resin 23 filled between the cylindrical portion 21 and the lid terminal 22 than the thickness of the power generation element 10. Specifically, the thickness of the power generation element 10 may be equal to or greater than the thickness of the lid terminal 22, and may be greater than the thickness of the lid terminal 22. Further, both surfaces of the power generation 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 generation element 10 may satisfy the relationship: thickness of the cylindrical portion 21 > thickness of the inner surface of the cylindrical portion 21 ≥ thickness of the power generation element 10 ≥ thickness of the lid terminal. Thereby, extra space can be eliminated, and the structural efficiency of the secondary battery 100 can be further improved.

[0020] Similarly, in the width direction, the power generation element 10 and the cylindrical portion 21 may be in contact with each other as long as either of them is subjected to an insulation treatment. In this case, the width of the lid terminal 22 may be made thinner by the thickness of the first resin 23 filled between the cylindrical portion 21 and the lid terminal 22 than the width of the power generation element 10. Specifically, the width of the power generation element 10 may be equal to or greater than the width of the lid terminal 22, and may be greater than the width of the lid terminal 22. Further, both surfaces of the power generation 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 generation element 10 may satisfy the relationship: width of the cylindrical portion 21 > width of the inner surface of the cylindrical portion 21 ≥ width of the power generation element 10 ≥ width of the lid terminal. Thereby, extra space can be eliminated, and the structural efficiency of the secondary battery 100 can be further improved.

[0021] The power generation element 10 may be a solid battery or a liquid battery. Preferably, it is a solid battery. Also, the type of the power generation element 10 is not particularly limited and can be applied to any secondary battery. For example, it may be a power generation element for a lithium-ion secondary battery or a power generation element for a sodium-ion secondary battery. Hereinafter, the materials of the power generation element of the lithium-ion secondary battery will be described.

[0022] (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-like metal foils. The metal constituting the positive electrode current collector 11a and the negative electrode current collector 11b is not particularly limited, and examples thereof include Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, etc. Al is preferable as the metal constituting the positive electrode current collector 11a. Cu is preferable as the material constituting the negative electrode current collector 11b. Also, 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.

[0023] The positive electrode current collector 11a and the negative electrode current collector 11b may have some coating layer (for example, a carbon coating layer) on their surfaces for adjusting 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.

[0024] (Positive electrode 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 cobaltate, lithium nickelate, lithium manganate, lithium nickel cobalt manganate, and spinel-based lithium compounds can be mentioned.

[0025] 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 can be used in a lithium-ion secondary battery. For example, butadiene rubber (BR), butylene rubber (IIR), acrylate butadiene rubber (ABR), polyvinylidene fluoride (PVdF), etc. can be mentioned. The conductive assistant is not particularly limited as long as it can be used in a lithium-ion secondary battery. For example, carbon materials such as acetylene black and ketjen black, and metal materials such as nickel, aluminum, and stainless steel can be mentioned.

[0026] 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 can be used in a lithium-ion secondary battery. For example, it may be an organic polymer electrolyte or an inorganic solid electrolyte. Preferably it is an inorganic solid electrolyte. This is because it has a higher ionic conductivity and better heat resistance compared to organic polymer electrolytes. The inorganic solid electrolyte may be an oxide solid electrolyte or a sulfide solid electrolyte. Preferably it is a sulfide solid electrolyte. Examples of the oxide solid electrolyte include lithium lanthanum zirconate, LiPON, Li 1+X AlXGe 2-X (PO4)3, Li-SiO-based glass, Li-Al-S-O-based glass, etc. can be mentioned. Examples 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.

[0027] The content of each component in the positive electrode active material layer may be appropriately set according to the purpose. Also, the surface of the positive electrode active material may be coated 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.

[0028] (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, Si 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 and lithium alloys, etc. can be mentioned.

[0029] The negative electrode active material layer may optionally contain a conductive assistant and a binder. The conductive assistant and the binder can be appropriately selected from the conductive assistant and the binder that can be used in the positive electrode active material layer. Further, 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 can be appropriately selected from the solid electrolytes that can be used in the positive electrode active material layer.

[0030] The content of each component in the negative electrode active material layer may be appropriately set according to 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.

[0031] (Electrolyte layer) When the secondary battery 100 is an all-solid-state battery, the electrolyte layer is a sheet-like solid electrolyte layer. The solid electrolyte layer contains a solid electrolyte. The solid electrolyte can be appropriately selected from the solid electrolytes that can be used in the positive electrode active material layer. Further, the solid electrolyte layer may optionally contain a binder. The binder can be appropriately selected from the 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 according to the purpose. The thickness of the solid electrolyte layer may be, for example, 0.1 μm or more and 1 mm or less.

[0032] When the secondary battery 100 is a liquid-based battery, the electrolyte layer includes an electrolytic solution and a separator. The electrolytic solution and the separator are not particularly limited as long as they are an electrolytic solution and a separator that can be used in a lithium-ion secondary battery. Examples of the separator include 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 electrolytic solution usually contains a non-aqueous solvent and a supporting salt. Examples of the non-aqueous solvent include carbonates, ethers, esters, nitriles, sulfones, lactones, and the like. Examples of the supporting salt include LiPF6, LiBF4, lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethane)sulfonimide (LiTFSI), and the like. The concentration of the supporting salt in the electrolytic solution is not particularly limited, but may be, for example, 0.5 mol / L or more and 5 mol / L or less. Further, the electrolytic solution may be added with any components such as a gas generating agent, a film forming agent, a dispersant, a thickening agent, and the like.

[0033] <Outer package part 20> The outer package part 20 has a cylindrical part 21 having opening parts 21a on two opposing surfaces, lid terminals 22 (a positive electrode lid terminal 22a and a negative electrode lid terminal 22b) arranged in the respective opening parts 21a, and a first resin 23 arranged between the cylindrical part 21 and the lid terminals 22, and the cylindrical part 21 and the lid terminals 22 are integrated by the first resin 23.

[0034] (Cylindrical part 21) The cylindrical part 21 has a hollow shape having opening parts 21a on two opposing surfaces. The opening parts 21a are respectively provided on the surfaces on both sides in the length direction of the cylindrical part 21. The shape of the cross section in the width direction of the cylindrical part 21 is rectangular. However, the cross-sectional shape of the cylindrical part is not limited to this. Fig. 3(a) shows a plan view of the cylindrical part 21, (b) shows a cross-sectional view in the width direction of the cylindrical part 21, and (c) shows a side view of the cylindrical part 21 viewed from the width direction.

[0035] The cylindrical part 21 is made of a metal having a high water vapor barrier property from the viewpoint of preventing deterioration of the power generation element. The metal having a high water vapor barrier property is, for example, a water vapor transmittance of 1.0×10-4 g / m 2 It is a metal with a period of less than 24 h. A lower water vapor transmission rate indicates a higher water vapor barrier property. Examples of such metals include aluminum, stainless steel, SUS, and Jeralmin. From the viewpoints of light weight and workability, aluminum may be adopted as the material of the cylindrical portion 21. Also, the fact that aluminum is inexpensive is an advantage.

[0036] The water vapor transmission rate can be measured using the cup method according to JIS Z 0208 or the gas chromatograph method according to JIS K 7129.

[0037] Here, from the viewpoint of suppressing a short circuit due to contact with the power generation element 10, the cylindrical portion 21 may be subjected to a predetermined insulation treatment. For example, an insulating material such as an insulating sheet may be disposed between the power generation element 10 and the cylindrical portion 21. Insulating materials may be disposed between the surfaces in the thickness direction of the power generation element 10 and the cylindrical portion 21, respectively. Also, insulating materials may be disposed between the surfaces in the width direction of the power generation element 10 and the cylindrical portion 21, respectively. Thereby, it is possible to suppress the power generation element 10 and the cylindrical portion 21 from being electrically connected and to suppress a short circuit of the secondary battery 100. Also, a metal laminate film (for example, an aluminum laminate film) obtained by covering at least the inner surface of the cylindrical portion 21 with an insulating resin may be used. Thereby, it is possible to suppress the power generation element 10 and the cylindrical portion 21 from being electrically connected without requiring the arrangement of an insulating material and to suppress a short circuit of the secondary battery 100. A metal laminate film is a multilayer body in which a resin (for example, polypropylene, nylon, PET, etc.) is disposed on the surface of a metal layer. Thus, an insulation treatment may be performed in which a predetermined insulation layer is disposed on the inner peripheral portion of the cylindrical portion 21.

[0038] However, the thickness of the metal layer of a general metal laminate film is usually about 0.04 mm, and since it is relatively thin, there is a problem of low strength. Therefore, the cylindrical portion 21 is preferably made of a metal having a thickness of 0.05 mm or more and 0.2 mm or less, and more preferably made of a metal having a thickness of 0.1 mm or more and 0.2 mm or less. Further, as the cylindrical portion 21, a metal laminate film including a metal layer having a thickness within the above range may be used. When using a metal laminate film for the cylindrical portion 21, a metal laminate film formed in a cylindrical shape is used.

[0039] The cylindrical portion 21 may be provided with a protruding portion 21b at an end in the length direction. Specifically, the cylindrical portion 21 may be provided with a protruding portion 21b on at least one of the surfaces in the thickness direction and the width direction at an end in the length direction. By providing the protruding portion 21b, it has the role of securing the adhesion area with the first resin 23 and improving the adhesive force. The protruding portion 21b refers to a portion protruding outside the base material layer 22c of the lid terminal 22.

[0040] Fig. 4(a) shows a cross-sectional view near the opening 21a of the cylindrical portion 21 provided with protruding portions 21b at both ends in the thickness direction. Further, Fig. 4(b) shows a cross-sectional view near the opening 21a of the cylindrical portion 21 provided with a protruding portion 21b bent inward.

[0041] In the cylindrical portion 21 shown in Fig. 4(a), protruding portions 21b are provided at both ends in the thickness direction. That is, it has a structure in which the ends in the thickness direction protrude more than the ends in the width direction of the cylindrical portion 21. As shown in Fig. 4(a), by having the protruding portion 21b, the cylindrical portion 21 can increase the adhesion area with the first resin 23 and improve the adhesive force. 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 not desirable. Further, as shown in Fig. 4(b), the protruding portion 21b may have a shape bent inward of the cylindrical portion 21. This facilitates the positioning of the lid terminal 22. In this case, the opening formed by the two protruding portions 21 becomes the opening 21a.

[0042] The angle between the protruding portion 21b and the surface of the cylindrical portion 21 (the surface having the protruding portion 21b) is not particularly limited and can take any angle from 0° to 180°. Preferably, it is 15° to 135°. The length of the protruding portion 21b is not particularly limited, but is, for example, in the range of 0.5 mm to 2 mm. However, it is adjusted so as not to exceed the surface 22f on the opening 21a side of the lid terminal 22.

[0043] (lid terminal 22) The lid terminals 22 (the positive electrode lid terminal 22a and the negative electrode lid terminal 22b) are arranged in the respective openings 21a of the cylindrical portion 21 and function as lids for the cylindrical portion 21. Further, the lid terminal 22 also functions as an electrode terminal of the battery 100. Thus, the lid terminal 22 is characterized by having two functions, namely, 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 of b in (a), and (c) shows a side view of the lid terminal 22 observed from the direction of c in (a).

[0044] The lid terminal 22 has a base material layer 22c and a convex portion 22d protruding outward from the base material layer 22c. The base material layer 22c has a rectangular outer peripheral shape and has a surface 22e inside it that can be connected to each current collector 11. The convex portion 22d has a rectangular shape that is slightly smaller than the base material layer 22c, and the convex portion 22d has a surface 22f on its outside for electrically connecting to an external power source or an electrical load. Further, the lid terminal 22 has a predetermined stepped portion 22g at the connection portion between the base material layer 22c and the convex portion 22d. The stepped portion 22g is a combination of the outer peripheral portion of the convex portion 22d and the outer surface of the base material layer 22c. However, the outer peripheral shape of the base material layer 22c is not particularly limited, and it may have a shape along the cross-sectional shape in the width direction of the cylindrical portion 21. The outer peripheral shape of the convex portion 22d is also not particularly limited. Further, the lid terminal 22 may not have the convex portion 22d. In this case, the outer surface of the base material layer 22c is electrically connected to an external power source or an electrical load. Fig. 6 shows an example of a lid terminal 122 without the convex portion 22d. Such a form is also included in the secondary battery of the present disclosure. Further, the lid terminal 22 may have a plurality of convex portions 22d. This form will be described later.

[0045] Since the lid terminal 22 functions as an electrode terminal, it is made of a material having electrical conductivity. Further, since the lid terminal 22 functions as a lid of the cylindrical portion 21, from the viewpoint of preventing deterioration of the power generation element 10, it is made of a material having high water vapor barrier properties. A material having high water vapor barrier properties is, for example, a material having a water vapor transmission rate of less than 1.0×10 -4 g / m 2 ·24 h. Materials for the lid terminal 22 that satisfy these conditions are, for example, metals. The metal that can be used for the lid terminal 22 is 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 lid terminal 22 may be the same as or different from the metal constituting the current collector 11. Al is preferable as the metal constituting the positive electrode lid terminal 22a. Cu is preferable as the material constituting the negative electrode lid terminal 22b. Further, the lid terminal 22 may be made of a material other than metal for portions 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.

[0046] Here, from the viewpoint of suppressing a short circuit due to contact between the lid terminal 22, the power generation element 10, and the cylindrical portion 21, a predetermined insulation treatment may be performed. For example, from the viewpoint of suppressing a short circuit due to contact between the lid terminal 22 and the power generation element 10, an insulating material such as an insulating sheet may be disposed between the lid terminal 22 and the power generation element 10 (electrode laminate). Thereby, it is possible to suppress the electrical connection between the electrical element 10 and the lid terminal 22 and suppress a short circuit of the secondary battery 100.

[0047] Also, from the viewpoint of suppressing a short circuit due to contact between the lid terminal 22 and the cylindrical portion 21, a metal laminate film in which at least the inner surface of the cylindrical portion 21 is covered with an insulating resin may be used. Thereby, without requiring the arrangement of an insulating material on the lid terminal 22, it is possible to suppress the electrical connection between the lid terminal 22 and the cylindrical portion 21 and suppress a short circuit of the secondary battery 100. Further, in order to suppress a short circuit due to contact with the cylindrical portion 21, the outer peripheral portion of the lid terminal 22 (the outer peripheral portion of the base material layer 22c and the stepped portion 22g) may be wrapped with an insulating film, an insulating tape may be attached to the outer peripheral portion of the lid terminal 22, or an insulating surface treatment may be performed. Thus, an insulating treatment for arranging a predetermined insulating layer on the outer peripheral portion of the lid terminal 22 may be performed. Also, an insulating treatment for arranging a predetermined insulating layer on a portion of the lid terminal 22 other than the surfaces 22e and 22f may be performed.

[0048] The length L1 of the base material layer 22c of the lid terminal 22 is not particularly limited, and when the cylindrical portion 21 and the lid terminal 22 are integrated with the first resin 23, it is sufficient if sufficient water vapor barrier properties can be exhibited. For example, it may be 0.2 mm or more, may be 0.5 mm or more, may be 3 mm or less, and may be 2 mm or less. The length L2 of the convex portion 22d of the lid terminal 22 is not particularly limited, but as shown in FIG. 2, when the first resin 23 is arranged on the outer peripheral portion of the convex portion 22d and the cylindrical portion 21 and the lid terminal 22 are integrated with the first resin 23, it is sufficient if sufficient water vapor barrier properties can be exhibited. For example, it may be 0.5 mm or more, may be 1 mm or more, may be 3 mm or less, and may be 2 mm or less.

[0049] In a conventional laminated battery, the electrode terminals are arranged to protrude to the outside. Since the electrode terminals are usually made of thin metal, for connection with an external member, the surface arranged in the thickness direction of the electrode terminal is used. On the other hand, for the lid terminal 22, the surface 22f arranged in the length direction is used for connection with an external member. In a sense, the surface 22f of the lid terminal 22 can be said to be a terminal in which the direction of a conventional electrode terminal is changed by 90°. Thus, by having the surface 22f arranged in the length direction, the lid terminal 22 facilitates connection with an external member.

[0050] The lid terminal 22 is electrically connected to the current collector 11 of the power generation element 10, but these connection methods are not particularly limited. For example, the surface 22e of the lid terminal 22 and the current collector 11 may be joined by known joining methods such as crimping by pressing, laser joining, ultrasonic joining, and joining using a conductive material. Also, as shown in FIG. 2, the current collector 11 may be electrically connected to the lid terminal 22 in a state of being curved in one direction. In this way, by electrically connecting the current collector 11 to the lid terminal 22 in a curved state, the structural efficiency can be improved. 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 the direction of opening the curve. Therefore, by arranging the lid terminal 22 in the direction of opening the curve of the current collector 11, the current collector 11 can be pressed against the lid terminal, and the connection between the current collector 11 and the lid terminal 22 can be strengthened.

[0051] Further, the lid terminal 22 may have a protruding portion 22h that protrudes inward from the end of the inner surface 22e of the base material layer 22c. The protruding portion 22h may be arranged at at least one end (in the thickness direction and / or the width direction) of the surface 22e, or may be arranged at a plurality of ends. Preferably, the protruding portions 22h are respectively arranged at opposite ends of the surface 22e, more preferably, the protruding portions 22h are arranged at the respective ends in the thickness direction and the width direction of the surface 22e, and even more preferably, the protruding portions 22h are arranged over the entire outer periphery of the surface 22e. FIG. 7 shows an example of the lid terminal 222 in which the protruding portions 22h are arranged at both ends in the thickness direction of the surface 22e. FIG. 7(a) is a side view of the lid terminal 222, and FIG. 7(b) is an example of the use of the lid terminal 222. In this way, since the lid terminal 222 has the protruding portion 22h, the contact area with the first resin 23 can be increased, and the adhesiveness with the cylindrical portion 21 can be improved. Also, since the lid terminal 222 can effectively utilize the space surrounded by the surface 22e and the protruding portion 22h, it is possible to improve the structural efficiency of the battery 100. The length L3 of the protruding portion 22h is not particularly limited, but may be, for example, 0.5 mm or more, 1 mm or more, 3 mm or less, or 2 mm or less.

[0052] In FIG. 2, the lid terminal 22 is used as an inner lid terminal disposed inside the opening 21a of the cylindrical portion 21. However, the lid terminal of the present disclosure is not limited to this, and it may be an outer lid terminal disposed outside so as to cover the opening 21a of the cylindrical portion 21. From the viewpoint of improving structural efficiency, the lid terminal 22 may be an inner lid terminal.

[0053] The width or thickness of the lid terminal 22 may be equal to or less than the width or thickness of the power generation element 10. The width or thickness of the lid terminal 22 is the maximum value of the width or thickness of the lid terminal 22, and typically is the width or thickness of the base material layer 22c of the lid terminal 22.

[0054] First, the width of the lid terminal 22 will be described. The width of the lid terminal 22 may be equal to or less than the width of the power generation element 10. In other words, this means that the width of the power generation element 10 is made equal to or greater than the width of the lid terminal 22. Thereby, extra space can be eliminated, and structural efficiency can be further improved. Similarly, the thickness of the lid terminal 22 may be equal to or less than the thickness of the power generation element 10. In other words, this means that the thickness of the power generation element 10 is made equal to or greater than the thickness of the lid terminal 22. Thereby, extra space can be eliminated, and structural efficiency can be further improved. The detailed relationship between the widths and thicknesses of the power generation element 10, the lid terminal 22, and the cylindrical portion 21 is as described above.

[0055] (First resin 23) The first resin 23 is disposed between the cylindrical portion 21 and the lid terminal 22, and integrates the cylindrical portion 21 and the lid terminal 22. Since the cylindrical portion 21 and the inner lid terminal 22 are integrated by the first resin 23 in this way, the secondary battery 100 can ensure sufficient water vapor barrier properties. Further, the first resin 23 may be used as an insulating member when connecting the lid terminal 22 and an external member.

[0056] As shown in FIG. 2, the first resin 23 fills the gap existing between the cylindrical portion 21 and the lid terminal 22. The "gap existing between the cylindrical portion 21 and the lid terminal 22" is the gap existing between the inner surface of the cylindrical portion 21 and the outer peripheral portion of the lid terminal 22. In order to form such a gap, the lid terminal 22 may be manufactured to be slightly smaller than the outer shape of the cylindrical portion 21. For example, the gap may be set to be 0.01 mm to 3 mm, and may be set in the range of 0.05 mm to 0.5 mm. By arranging the first resin 23 in the above-mentioned gap as described above, the cylindrical portion 21 and the lid terminal 22 are integrated with the first resin 23. Here, the first resin 23 only needs to fill at least a part of the gap existing between the cylindrical portion 21 and the lid 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 will be described later, when the second resin 24 is filled inside the cylindrical portion 21, the second resin 24 may be arranged in the gap formed by the cylindrical portion 21 and the lid terminal 22 in addition to the first resin 23.

[0057] Also, when the lid terminal 22 has the convex portion 22d, the first resin 23 may be arranged not only between the cylindrical portion 21 and the lid terminal 22 but also on at least a part of the outer peripheral surface of the convex portion 22d. As shown in FIG. 2, the first resin 23 is arranged on the entire outer peripheral surface of the convex portion 22d to fill the step portion 22g formed by the base material layer 22c and the convex portion 22d with the first resin 23. That is, the first resin 23 may be arranged so as to fill the step portion 22g. At this time, the surface of the first resin 23 on the opening portion 21a side may be arranged to be flush with the surface 22f of the lid terminal 22. In this way, by filling the step portion 22g formed by the material layer 22c and the convex portion 22d with the first resin 23, the water vapor barrier property can be enhanced.

[0058] Thus, since the exterior part 20 fills the path (gap) through which water vapor enters from the outside to the inside with the first resin 23, it is possible to sufficiently suppress the intrusion of water vapor into the interior of the exterior part 20. In other words, this means that there may be a gap through which water vapor can enter between the cylindrical part 21 and the lid terminal 22 in the exterior part 20. Since such a gap is filled with the first resin 23, it is not necessary to strictly design the cylindrical part 21 and the lid terminal 22.

[0059] Here, "integrated" means that each material is adhered by resin and integrated to the extent that it can be recognized as one member. The "integration" by the first resin 23 is possible by placing the cylindrical part 21 that houses the power generation element 10 inside and the intermediate member with the lid terminal 22 disposed at the opening 21a of the cylindrical part 21 in a predetermined mold, injecting the first resin into the mold, and curing it. In this way, the exterior body 20 can be manufactured by integral molding using the first resin 23.

[0060] In this way, the secondary battery 100 seals the power generation element 10 using the exterior part 20 instead of the conventional laminated exterior body, thereby having a water vapor barrier property equivalent to or higher than that of the conventional laminated exterior body. Also, in the case of the conventional laminated exterior body, when heat-sealing the end portion after housing the power generation element inside, sealing defects may occur. In such a case, since water vapor can enter from the sealing defect site, the water vapor barrier property cannot be ensured. On the other hand, since the secondary battery 100 seals the power generation element 10 inside the exterior part 20 using the first resin 23, defects due to sealing are very unlikely to occur. Therefore, it may not be necessary to perform a water vapor barrier property inspection (leak inspection) after manufacturing the secondary battery 100.

[0061] From the viewpoint of preventing deterioration of the power generation element, the first resin 23 uses a resin having a water vapor barrier property. A resin having a water vapor barrier property is, for example, a resin with a water vapor permeability of 1.0×10 -4 g / m 2 ·24h or more and 50×10 -4 g / m 2· It is a resin with a curing time of 24 hours or less. The type of such resin is not particularly limited, and examples include thermoplastic resins. The thermoplastic resin is not particularly limited, and examples include polypropylene, polyester, and the like.

[0062] <Structural efficiency improvement> Next, the structural efficiency improvement by the secondary battery 100 will be described. FIGS. 8 and 9 show diagrams comparing the conventional laminated battery and the secondary battery 100. FIG. 8 is a diagram comparing the longitudinal sectional views of the conventional laminated battery (a) and the secondary battery 100 (b). FIG. 9 is a diagram comparing the plan views of the conventional laminated battery (a) and the secondary battery 100 (b).

[0063] As shown in FIG. 8(a), the conventional laminated battery has a terminal portion (region A) protruding from the laminated exterior body, a heat-sealed portion (region B) where the laminated exterior body is heat-sealed, a joint portion (region C) where the electrode terminal and the current collector are joined, and a current collector portion (region D) where a plurality of current collectors connected to the power generation element are present.

[0064] As shown in FIG. 8(b), by using the exterior portion 20, the secondary battery 100 can make the length of all regions shorter than that of the conventional laminated battery. Specifically, it is as follows.

[0065] First, the reason why the length of the portion corresponding to region A becomes shorter will be explained. Since the secondary battery 100 uses the lid terminal 22, the terminal portion (surface 22f) is orthogonal to the longitudinal 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 disposed on the step portion 22g of the lid terminal 22, the convex portion 22d of the lid terminal 22 may protrude more than the first resin 23. Even in such a case, the portion corresponding to region A can be made infinitely shorter than that of the conventional laminated battery.

[0066] Next, the reason why the length of the portion corresponding to region B becomes short will be explained. In a conventional laminated battery, the region B (seal width) usually needs to be set to a length exceeding 3 mm. This is due to the following reasons. (1) If the seal width is short, proper heat welding may not be possible, resulting in seal defects in some cases. (2) Since the laminated exterior body does not have high rigidity, if the seal width is short, the adhesion of the seal region may be peeled off by an external impact, and the adhesion surface may not be maintained in some cases. (3) During heat welding, if the terminal is not parallel to the adhesion surface of the laminated exterior body, when the seal width is short, the correcting force to return the inclination becomes weak, so proper heat welding cannot be performed and the probability of seal defects increases further. (4) During heat welding, if the seal width is short, the pressure per area applied to the seal region by the heat welding head increases, and there is a risk that the metal layer inside the laminated exterior body will bite into the terminal across the insulating layer. If the metal layer bites into the terminal, it causes a short circuit, which is not desirable.

[0067] On the other hand, in the secondary battery 100, an exterior portion 20 in which the cylindrical portion 21 and the lid terminal 22 are integrated with the first resin 23 is used. By integrating with the first resin 23 in this way, the adhesion failure between the cylindrical portion 21 and the lid terminal 22 can be extremely highly suppressed. Also, even when the lid terminal 22 is inclined and the gap between the cylindrical portion 21 and the lid terminal 22 is not parallel, proper adhesion can be achieved. Furthermore, since heat welding is not performed, almost no short circuit occurs. In addition, by integrating with the first resin 23, rigidity is ensured, so peeling of the adhesion portion is also suppressed. Therefore, the secondary battery 100 can set the length (L1 + L2) of the portion corresponding to region B of the conventional laminated battery to 3 mm or less. Also, it may be 2 mm or less, or may be 0.5 mm or more, or may be 1 mm or more. Thus, the secondary battery 100 can shorten the length of the portion corresponding to region B compared to the conventional laminated battery.

[0068] Next, the reason why the length of the portion corresponding to region C becomes shorter will be described. As shown in FIG. 8(b), since the surface 22e of the lid terminal 22 of the secondary battery 100 is orthogonal to the length direction, the current collector foil 11 is joined to the surface 22e of the lid terminal 22 in a curved state. Therefore, the length of the joined portion becomes very short. Accordingly, the secondary battery 100 can shorten the length of the portion corresponding to region C as compared with the conventional laminate type battery.

[0069] Finally, the reason why the length of the portion corresponding to region D becomes shorter will be described. As described above, the current collector foil 11 is joined to the surface 22e of the lid terminal 22 in a curved state. Therefore, the length of the portion where the current collector 11 exists also becomes very short. Thus, the secondary battery 100 can shorten the length of the portion corresponding to region D as compared with the conventional laminate type battery.

[0070] Next, FIG. 9 will be described. As shown in FIG. 9, the conventional laminate type battery requires heat-sealing portions S on the maximum four sides of the outer periphery. On the other hand, both end portions in the length direction of the secondary battery 100 are structurally optimized by the exterior portion 20 as described above. Further, since the secondary battery 100 uses a cylindrical portion 21 which is a cylindrical metal body, heat-sealing portions are not required on both sides in the width direction. Accordingly, the secondary battery 100 is structurally optimized in this respect. Further, since there are no heat-sealing portions on both sides in the width direction, the water vapor barrier property is also improved.

[0071] Incidentally, the advantages of the secondary battery 100 over the laminated battery using a lid as described in Patent Documents 2 and 3 will also be described. Even in the case of a laminated battery using a lid, the lengths of Region A and Region D are equivalent to those of a conventional laminated battery. Also, the length of Region B is equivalent to that of a conventional laminated battery (a length exceeding the seal width: 3 mm). This is almost the same as the reason for the conventional laminated battery, but specifically as follows. (1) If the seal width is short, there may be a sealing defect. (2) Since the laminated exterior body does not have high rigidity, if the seal width is short, the adhesion of the seal region may peel off due to an external impact, and the adhesion surface may not be maintained. (3) Also, when the lid tilts due to an external impact, the corrective force to return the tilt may be weak, so the adhesion surface may not be properly maintained. (4) During heat welding, if the outer peripheral surface of the lid is not parallel to the welding surface of the laminated exterior body, if the seal width is short, the corrective force to return the tilt becomes weak, so the probability of a sealing defect increases further. Furthermore, the length of Region C also becomes equivalent to that of a conventional laminated battery, depending on the form of the lid. In addition, when the laminated exterior body is formed into a cylindrical shape, a seal region may be required on the side surface. For the above reasons, the secondary battery 100 has improved structural efficiency even when compared to a laminated battery having a lid.

[0072] As described above, the secondary battery 100 can significantly improve its structural efficiency compared to a conventional laminated battery.

[0073] <Short - circuit suppression between the power - generating element 10 and the exterior part 20> When the cylindrical part 21 and the lid 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. In the following, specific forms of disposing the insulating material will be described.

[0074] First, a secondary battery 101 filled with a second resin 24 inside the exterior part 20 will be described. FIG. 10 shows a longitudinal cross - sectional view of the secondary battery 101 in which the entire inside of the exterior part 20 is filled with the second resin 24.

[0075] As shown in FIG. 10, the exterior portion 20 includes 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 portion 20, but is not limited thereto, and may be disposed at a position where the power generation element 10 and the exterior portion 20 can come into contact. Preferably, the second resin 24 is disposed throughout the interior of the exterior portion 20.

[0076] Thus, by providing the second resin 24 inside the exterior portion 20, the cylindrical portion 21, the lid terminal 22, and the power generation element 10 can be integrated with the second resin 24. Thereby, a short circuit due to contact between the power generation element 10 and the exterior portion 20 can be suppressed. For example, even when a predetermined insulating layer is disposed on the power generation element 10 or the exterior portion 20, the insulating layer may be broken by an external impact, and the power generation element 10 and the exterior portion 20 may come into contact and cause a short circuit. In contrast, by disposing the second resin 24 inside the exterior portion 20, the contact between the power generation element 10 and the exterior portion 20 can be more suppressed compared to the case where only the insulating layer is disposed, and a short circuit of the battery can be suppressed.

[0077] Further, the secondary battery 100 can further improve the water vapor barrier property by including the second resin 24. Furthermore, by integrating each member with the second resin 24, the movement of the power generation element 10 due to an external impact can be suppressed, so that the disconnection of the current collector 11 due to the movement of the power generation element 10 can be suppressed. In addition, chipping and slipping of the power generation element 10 due to an external impact can also be suppressed.

[0078] The method of filling the second resin 24 inside the exterior part 20 is not particularly limited. For example, holes for injecting the second resin 24 may be provided at predetermined locations of the cylindrical part 21. The shape of the holes 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 with different shapes may be provided on the side surface of the cylindrical part 21. Also, at least one hole may be provided in the lid terminal 22. For example, as shown in FIG. 5(b), a plurality of holes 22i may be provided in the lid terminal 22. In addition, when using a power generation element 10 for a liquid-based battery as the power generation element, after filling the second resin 24, a predetermined electrolytic solution may be injected through the holes.

[0079] Next, a secondary battery 102 in which the power generation element 10 is wrapped with a resin film 13 having insulating and water vapor barrier properties will be described. FIG. 11 shows a longitudinal sectional view of the secondary battery 102 in which the power generation element 10 is wrapped with the resin film 12. FIG. 12 shows a plan view of the power generation element 10 wrapped with the resin film 12.

[0080] As shown in FIGS. 11 and 12, the resin film 12 has a cylindrical shape and has openings on the side where the lid terminal 22 is disposed. And the resin film 12 wraps the entire power generation element 10 (excluding the current collector 11 which is a tab). In FIG. 12, the members disposed inside the resin film 12 are shown by dotted lines. By thus entirely wrapping the power generation element 10 with the resin film 12, it is possible to suppress a short circuit due to contact between the power generation element 10 and the exterior part 20 (particularly the cylindrical part 21). Also, the secondary battery 100 can further improve its water vapor barrier property by including the resin film 12.

[0081] The resin film 12 may be a resin film having insulating and water vapor barrier properties. For example, a resin film with aluminum or silica vapor-deposited thereon can be mentioned. The type of resin is not particularly limited, and examples include polypropylene and polyethylene terephthalate.

[0082] Note that the power generation element 10 may be wrapped with a resin film 12, and the second resin 24 may be filled inside the exterior portion 20.

[0083] <Other forms of the cylindrical portion> From the viewpoint of structural efficiency, as shown in FIG. 3, the cylindrical portion 21 may be a cylindrical metal body or a metal laminate film formed into a cylindrical shape. Preferably, it is a cylindrical metal body. On the other hand, in such a cylindrical portion, there is a problem that it is difficult to accommodate the power generation element 10 inside. Therefore, the following cylindrical portions 121 and 221 that are easy to accommodate the power generation element 10 may be used.

[0084] First, the cylindrical portion 121 will be described. FIG. 13(a) shows a plan view of the cylindrical portion 121, and FIG. 13(b) shows a cross-sectional view in the width direction of the cylindrical portion 121. As shown in FIG. 13, the cylindrical portion 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 a protruding portion 121c protruding in the same direction from an end portion opposite to the bottom surface 121b. As shown in FIG. 13(b), the two metal plates 121a are overlapped upside down, and the protruding portions 121c of the two metal plates 121a are overlapped on each opposite side surface (surface in the width direction) of the cylindrical portion 121. Then, a third resin 121c is disposed so as to cover each side surface of the cylindrical portion 121. Specifically, the third resin 121c entirely covers the side surface side of the overlapping protruding portions 121c of the metal plates 121a and fills the gap between the overlapping protruding portions 121c of the metal plates 121a. Thereby, the end portions of the overlapping metal plates 121a are integrated by the third resin 121c.

[0085] Since the cylindrical portion 121 includes two metal plates 121a, after disposing the power generation element 10 inside one of the metal plates 121a, the other metal plate 121a is overlapped upside down, and the protruding portions 121c of the metal plates 121a are integrated with the third resin 121d, whereby the cylindrical portion 121 can be manufactured. In this way, by using the cylindrical portion 121, the power generation element 10 can be easily accommodated inside the cylindrical portion 121.

[0086] Next, the cylindrical portion 221 will be described. FIG. 14(a) shows a plan view of the cylindrical portion 221, and FIG. 14(b) shows a cross-sectional view of the cylindrical portion 221 in the width direction. As shown in FIG. 14, the cylindrical portion 221 is composed of a single metal plate 221a and a third resin 221d. The metal plate 221a is formed into a cylindrical shape, and the end portion 221b of the metal plate 221a is overlapped on one side surface of the cylindrical portion 221. Then, the third resin 221c is disposed so as to cover the side surface where the end portions 221b are overlapped. Specifically, the third resin 221c entirely covers the side surface side of the overlapped end portions 221b and fills the gap between the overlapped end portions 221b of the metal plate 221a. Thereby, the overlapped end portions 221b of the metal plate 221a are integrated by the third resin 221c.

[0087] Since the cylindrical portion 221 is composed of a single metal plate 121a, after the power generation element 10 is disposed inside the cylindrical metal plate 221a, the cylindrical portion 221 can be produced by integrating the end portion 221b with the third resin 121c. Thus, by using the cylindrical portion 221, the power generation element 10 can be easily accommodated inside the cylindrical portion 221. Also, as shown in FIG. 15, by bringing the side surface of the cylindrical portion 221 where the third resin 221c is not disposed into contact with a predetermined cooling portion X, the secondary battery can be easily cooled. Note that such a cooling mode can also be applied to the secondary battery using the cylindrical portion 21.

[0088] The metal plates used in the above two forms may be mere metal plates or metal laminate films. In the illustrated embodiment, a metal plate is used. The type of metal may be a metal having high water vapor barrier properties. As the third resin used in the above two forms, the same resin as the first resin 23 can be used. Also, the "integration" by the third resin can be achieved by disposing the overlapped metal plate 121a or the metal plate 221a formed into a cylindrical shape in a predetermined mold, injecting the third resin into the mold, and curing it. Thereby, the cylindrical portions 121 and 221 can be manufactured.

[0089] <Other Forms of the Lid Terminal> From the perspective 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. Hereinafter, the secondary battery 103 having the lid terminal 322 with the slit portion 322j will be described.

[0090] Fig. 16 shows a perspective view of the secondary battery 103. Fig. 17(a) shows a longitudinal sectional view taken along XVIIa-XVIIa of Fig. 16, (b) shows a longitudinal sectional view taken along XVIIb-XVIIb of Fig. 16, and (c) shows a longitudinal sectional view taken along XVIIc-XVIIc of Fig. 16. Fig. 18(a) shows a perspective view of the lid terminal 322, (b) shows a front view of the lid terminal 322 observed from the direction of b in (a), and (c) shows a rear view of the lid terminal 22 observed from the direction of c in (a).

[0091] The secondary battery 103 mainly differs from the secondary battery 100 in the following points. That is, the power generation element 310 has a plurality of current collectors 311, the inner surface 322e of the lid terminal 322 has a plurality of slit portions 322j, and the current collector 311 is disposed in the slit portion 322j, whereby the current collector 311 and the lid terminal 322 are electrically connected. By adopting such a form, the distance between the power generation element 310 (electrode laminate) and the lid terminal 322 can be shortened, and the structural efficiency can be further improved. The detailed effects will be described later.

[0092] The form of the power generation element 310 is changed from the curved current collector 11 of the power generation element 10 described above to a straight current collector 311. Thereby, as shown within the dotted line frame in Fig. 17(a), the current collector 311 can be inserted and disposed in the slit portion 322j. Here, in Fig. 17(a), the power generation element 310 has a plurality of current collectors 311. However, the secondary battery of the present disclosure is not limited thereto, and the current collector 311 may be at least one.

[0093] The lid terminal 322 has a base material layer 322c and convex portions 322d respectively arranged at the widthwise ends of the base material layer 322c. The convex portions 322d are provided with substantially circular concave portions 322k to facilitate connection with an external member. The concave portion 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 press-fitting or riveting. Also, as shown in FIGS. 17(a) and 18(c), the inner surface 322e of the base material layer 322c of the lid terminal 322 has a plurality of slit portions 322j. And when the current collector 311 is arranged in the slit portions 322j, the current collector 311 and the lid terminal 322 are electrically connected.

[0094] In the secondary battery 103, the lid terminal 322 having two convex portions 322d is adopted, but the form of the lid terminal is not limited to this. It is only necessary that the inner surface 322e of the lid terminal 322 has slit portions 322j, and the outer form is not particularly limited. Also, in the secondary battery 103, the lid terminal 322 having a plurality of slit portions 322j is used, but the number of slit portions may be at least one.

[0095] The slit portions 322j penetrate in the length direction of the lid terminal 322, and the current collector 311 is arranged inside thereof. However, the slit portions 322j do not necessarily have to penetrate. Whether to penetrate the slit portions 322j can be appropriately set according to the joining method with the current collector 311.

[0096] The current collector 311 may be inserted from the inner surface 322e of the lid terminal 322, or may be inserted from the side surface (the surface in the thickness direction or the width direction). That is, the base material layer 322c of the lid terminal 322 may also have the opening l of the slit portion 322 on the side surface. The thickness of the slit portion 322i is not particularly limited, as long as it is a thickness capable of disposing the current collector foil 311. For example, it is 0.1 μm or more and 1 mm or less. The slit portion 322j is provided with an opening 322l for inserting the current collector 311. In order to facilitate the insertion of the current collector 311, the opening 322l may have a shape that is wider in the thickness direction than the inside (for example, a V-shaped). Inside the dotted line in FIG. 17(a), the state of inserting the current collector 311 from the inner surface 322e of the lid terminal 322 is shown.

[0097] Also, FIG. 19 shows a front view and a plan view of a lid terminal provided with a slit portion for inserting the current collector 311 from the side surface. (a) in FIG. 19 is an example of a lid terminal having two convex portions. (b) in FIG. 19 is an example of a lid terminal having one convex portion. As shown in (a), it is technically feasible to provide a slit portion on the back side of the convex portion, but it is likely to be difficult. Therefore, as shown in (b), it is common to provide the convex portion only at a position that does not overlap the slit portion.

[0098] When the lid terminal 322 has a slit portion 322j penetrating in the length direction, the first resin 323 may be disposed so as to cover the entire outer opening of each slit portion 322j. For example, as shown in FIG. 16, the first resin 323 may be disposed so as to cover the entire outer surface of the base material layer 322c. Thereby, the intrusion of outside air (water vapor) from the slit portion 322j into the exterior portion 320 can be suppressed. Note that the first resin 323 may enter the slit portion 322j and at least a part of the inside thereof may be filled with the first resin 323.

[0099] The connection form between the current collector 311 and the lid terminal 322 is not particularly limited, and it is only necessary that the current collector 311 is disposed in the slit portion 322j. However, from the viewpoint of strengthening the connection between the current collector 311 and the lid terminal 322, the slit portion 311i (lid terminal 322) and the current collector 311 may be joined in a state where the current collector 311 is disposed in the slit portion 322j. The joining method is not particularly limited, and known joining methods such as crimping by pressing, laser joining, ultrasonic joining, and conductive material fixing method can be adopted. When the slit portion 322j penetrates, laser joining or conductive material fixing method may be adopted. When the slit portion 322j does not penetrate, press working or ultrasonic working may be adopted.

[0100] Here, the slit portion 322j will be further described. FIG. 17(a) shows a form in which one current collector is disposed in one slit portion 322j. By adopting such a form, the distance between the power generation element 310 (electrode laminate) and the lid terminal 322 can be made close. Also, it is possible to make the distance between the power generation element 310 (electrode laminate) and the lid terminal 322 almost zero or zero (see FIG. 17(a)). On the other hand, depending on the shape of the lid terminal 322, it may be difficult to dispose one current collector in one slit portion 322j. Therefore, two or more current collectors may be disposed in one slit portion 322j. For example, two current collectors may be disposed in one slit portion 322j, three current collectors may be disposed, or four current collectors may be disposed. However, the larger the number of current collectors 311 disposed in one slit portion 322j, the greater the possibility that the distance between the power generation element 310 and the lid terminal 322 will become longer. Therefore, the number of current collectors disposed in one slit portion 322j may be 10 or less, or 8 or less.

[0101] 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, a region for overlapping the two current collectors 311 is required. This region tends to become longer as the number of current collectors 311 to be overlapped increases. Therefore, from the viewpoint of improving structural efficiency, it is better that the number of current collectors 311 arranged in one slit portion 322j is smaller, and the form in which one current collector 311 is arranged in one slit portion 322j is the best.

[0102] The distance between the lid terminal 322 and the power generation element 310 (electrode laminate) is not particularly limited. The closer the distance is, the more the structural efficiency is improved. For example, it may be 2 mm or less, or 0.5 mm or less, or 0 mm, that is, the lid terminal 322 and the power generation element 310 may be in contact with each other. However, when the lid terminal 322 and the power generation element 310 are in contact with each other, at least one of the lid terminal 322 and the power generation element 310 needs to be subjected to a predetermined insulation treatment.

[0103] Fig. 18(c) shows a form 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 generation element 310 are arranged side by side in the thickness direction. Thus, the arrangement direction of the slit portions 322j can be set along the arrangement direction of the current collectors 311 of the power generation 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 appropriately set according to the arrangement direction of the current collectors of the power generation element.

[0104] Also, as shown in Fig. 18(c), the slit portion 322j is arranged at the center of the inner surface 322e of the base material layer 322c. This is to avoid the recess 322k of the convex 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 lid terminal and the like.

[0105] As described above, by using the lid terminal 322 having the slit portion 322j, the distance between the lid terminal 322 and the power generation element 310 (electrode laminate) can be set short. On the other hand, when the distance between the lid terminal 322 and the power generation element 310 (electrode laminate) becomes short, a problem of short circuit due to contact may occur. Therefore, a predetermined insulation treatment may be performed on the lid terminal 322.

[0106] The insulation treatment for the lid terminal 322 is not particularly limited. For example, the outer peripheral portion of the lid terminal 322 may be wrapped with an insulating film, an insulating tape may be attached to the outer peripheral portion of the lid terminal 322, or an insulating sheet may be disposed on the outer peripheral portion of the lid terminal 322. Thus, an insulation treatment of disposing a predetermined insulating layer on the outer peripheral portion of the lid terminal 22 may be performed. In particular, from the viewpoint of suppressing a short circuit due to contact between the power generation element 10 and the lid terminal 322, an insulating sheet may be disposed between the power generation element 310 (electrode laminate) and the lid terminal 322. Examples of the insulating sheet include insulating resins such as polyethylene terephthalate (PET), polyolefin (PO) such as polyethylene (PE) and polypropylene (PP), and fluororesin.

[0107] FIG. 21(a) shows a form in which an insulating sheet 325 is disposed between the power generation element 10 and the lid terminal 322. Since the current collector 311 is disposed in the slit portion 322j, the insulating sheet 325 is provided with 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 in accordance with the position and number of the slit portions 322j. Further, as shown by the dotted line portion in FIG. 21(a), the slit 325 is provided with an opening 325a for inserting the current collector 311, and the opening 325a may have a shape that is wider in the thickness direction than the inside (for example, a V-shaped) in order to facilitate the insertion of the current collector 311. When the current collector 311 is inserted from the side surface of the lid terminal 322, an opening is also disposed on the side surface of the insulating sheet 325.

[0108] In addition, FIG. 21(b) shows an example of the arrangement form of the insulating sheet 325 when two current collectors 311 are arranged in one slit portion 322j. Thus, 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 generation element 10 and the lid terminal 322. Here, when the opening 325a of the slit 325a of the insulating sheet 325 has a shape that is wide in the thickness direction, it is also possible to arrange the region 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 generation element 310 (electrode laminate) can be shortened. FIG. 21(c) shows an example of the arrangement form 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 shape that is wide in the thickness direction. As shown in FIG. 21(c), the power generation element 310 (electrode laminate) can be arranged at a position where it almost contacts or contacts the insulating sheet 325.

[0109] The insulating sheet 325 may be arranged between the surface of the power generation element 310 in the width direction or the thickness direction and the inner surface of the cylindrical portion 321 in the width direction or the thickness direction for insulation between the power generation element 10 and the cylindrical portion 321, or may be arranged between the surfaces of the power generation element 310 in the width direction and the thickness direction and the inner surfaces of the cylindrical portion 321 in the width direction and the thickness direction. As an example, FIG. 21 shows an example of a form in which the insulating sheet 325 is arranged between the surface of the power generation element 310 in the thickness direction and the inner surface of the cylindrical portion 321 in the thickness direction.

[0110] (Structural efficiency improvement) The structural efficiency improvement of the secondary battery 103 will be described. FIG. 23 is a figure corresponding to FIG. 8, and (c) shows a longitudinal sectional view of the secondary battery 103, and a figure comparing the longitudinal sectional views of the conventional laminated battery (a), the secondary battery 100 (b), and the secondary battery 103 (c) is shown. Note that, in the secondary battery 103 shown in (c), a current collector is shown for easy comparison.

[0111] The comparison results between the laminated battery (a) and the secondary battery 100 (b) are as described above. Therefore, here, the secondary battery 100 (b) and the secondary battery 103 (c) will be compared and studied. As can be seen from FIG. 23, in the secondary battery 103, region D is even shorter than in the secondary battery 100. The reason for this is that in the secondary battery 100, the current collector 11 is joined to the lid terminal 22 in a curved state, whereas in the secondary battery 103, the current collector 311 is arranged in the slit portion 322j of the lid terminal 332, whereby the distance between the lid terminal 322 and the power generation element 310 can be further shortened. Therefore, according to the secondary battery 103, the structural efficiency can be further improved. Further, along with this structural efficiency improvement, it is possible to suppress the existence of surplus space inside the exterior portion 320, and thus the rigidity of the secondary battery 103 can be improved.

[0112] (Resin filling into the interior) In the secondary battery 103, when the interior is filled with the second resin 324, the second resin 324 may be arranged throughout the interior of the exterior portion 320. However, since the resin has the property that although in a small amount, water vapor diffuses inside, there is a risk that external water vapor diffuses inside the first resin and the second resin and reaches the end face of the power generation element. Specifically, as shown in FIG. 24, there is a risk that water vapor reaches the lengthwise surface of the power generation element 310 (electrode laminate) closest to the first resin.

[0113] Therefore, considering the water vapor diffusion inside the resin, the second resin 324 should not be disposed between the lid terminal 322 and the power generation element 310. In other words, the second resin 324 may be disposed only at a position where the power generation element 10 and the exterior portion 20 can come into contact. Specifically, the second resin 324 may be disposed only between the surface in the width direction or the thickness direction of the power generation element 310 and the inner surface in the width direction or the thickness direction of the cylindrical portion 321, and the second resin 324 may be disposed only between the surface in the width direction and the thickness direction of the power generation element 310 and the inner surface in the width direction and the thickness direction of the cylindrical portion 321. As an example, FIG. 25(a) shows an example of a form in which the second resin 324 is disposed between the surface in the thickness direction of the power generation element 310 and the inner surface in the thickness direction of the exterior portion. The reason why such a form is possible is that, as described above, the secondary battery 103 can shorten the distance between the lid terminal 322 and the power generation element 310 (electrode laminate). Further, even in such a form, the cylindrical portion 321, the lid terminal 322, and the power generation element 310 can be integrated with the second resin 324.

[0114] Further, FIG. 25(b) shows an example of a form in which an insulating sheet 325 is further disposed between the lid terminal 322 and the power generation element 310. Thus, by disposing the insulating sheet 325, it is possible to further suppress the penetration of the water vapor diffusing inside the resin into the power generation element 310 (electrode laminate).

[0115] Further, by disposing the second resin 324 only at a position where the power generation element 310 and the cylindrical portion 321 can come into contact, it is possible to suppress the collector 311 from being cut or torn during the filling of the second resin 324.

[0116] As described above, the secondary battery of the present disclosure has been described using the secondary batteries 100 to 103 which are one embodiment. As described above, the secondary battery of the present disclosure can achieve structural efficiency. The secondary battery of the present disclosure can be used for any application. For example, the secondary battery of the present disclosure can be used as an in-vehicle secondary battery.

Description of Reference Numerals

[0117] 10, 310 Power generation element 11, 311 Current collector 11a Positive current collector 11b Negative current collector 12 Resin film 20, 320 Exterior part 21, 121, 221, 321 Cylindrical part 21a Opening 21b Protrusion 21c Hole 21d Hole 22, 122, 222, 322 Cover terminal 22a Positive cover terminal 22b Negative cover terminal 22c, 322c Base material layer 22d, 322d Convex part 22e, 322e Surface 22f Surface 22g Step part 22h Protrusion 22i Hole 23, 323 Resin (first resin) 24 Second resin 100, 101, 102, 103 Secondary battery 121a, 221a Metal plate 121b Bottom surface 121c Protrusion 121d, 221c Third resin 221b End part 322j Slit part 322k Concave part 322l Opening 325 Insulating sheet 325a Slit

Claims

1. A power generation element and an exterior part that houses the power generation element therein, The exterior part has a cylindrical part having openings on two opposing surfaces, Cover terminals disposed at each of the openings, and resin disposed between the cylindrical part and the cover terminals, The cylindrical part and the cover terminals are integrated with the resin, The current collector of the power generation element and the cover terminals are directly connected, The width or thickness of the cover terminals is less than or equal to the width or thickness of the power generation element, A secondary battery.

2. A power generation element and an exterior part that houses the power generation element therein, The exterior part has a cylindrical part having openings on two opposing surfaces, Cover terminals disposed at each of the openings, and resin disposed between the cylindrical part and the cover terminals, The cylindrical part and the cover terminals are integrated with the resin, The current collector of the power generation element and the surface of the cover terminals facing the power generation element are connected, The width or thickness of the cover terminals is less than or equal to the width or thickness of the power generation element, A secondary battery.

3. A power generation element and an exterior part that houses the power generation element therein, The exterior part has a cylindrical part having openings on two opposing surfaces, Cover terminals disposed at each of the openings, and resin disposed between the cylindrical part and the cover terminals, The cylindrical part and the cover terminals are integrated with the resin, The current collector of the power generation element and the cover terminals are directly connected, The width or thickness of the cover terminals is less than or equal to the width or thickness of the power generation element, The power generation element has at least one current collector, The inner surface of the lid terminal has at least one slit portion, By disposing the current collector in the slit portion, the current collector and the lid terminal are electrically connected, Secondary battery.

4. A power generation element and an exterior portion that houses the power generation element therein, The exterior portion has a cylindrical portion having openings on two opposing surfaces, Lid terminals disposed at each of the openings, And a resin disposed between the cylindrical portion and the lid terminal, The cylindrical portion and the lid terminal are integrated with the resin, The current collector of the power generation element and the surface of the lid terminal facing the power generation element are directly connected, The width or thickness of the lid terminal is less than or equal to the width or thickness of the power generation element, The power generation element has at least one current collector, The inner surface of the lid terminal has at least one slit portion, By disposing the current collector in the slit portion, the current collector and the lid terminal are electrically connected, Secondary battery.

5. A power generation element and an exterior portion that houses the power generation element therein, The exterior portion has a cylindrical portion having openings on two opposing surfaces, Lid terminals disposed at each of the openings, And a resin disposed between the cylindrical portion and the lid terminal, The cylindrical portion and the lid terminal are integrated with the resin, The current collector of the power generation element and the lid terminal are directly connected, The width or thickness of the lid terminal is less than or equal to the width or thickness of the power generation element, An insulating sheet is disposed between the power generation element and the lid terminal, Secondary battery.

6. It includes a power generation element and an exterior part that houses the power generation element inside. The exterior part has a cylindrical part with openings on two opposing surfaces. It has lid terminals arranged at each of the openings. It has a resin arranged between the cylindrical part and the lid terminals. The cylindrical part and the lid terminals are integrated with the resin. The current collector of the power generation element and the surface of the lid terminal facing the power generation element are connected. The width or thickness of the lid terminal is less than or equal to the width or thickness of the power generation element. An insulating sheet is arranged between the power generation element and the lid terminal. Secondary battery.

7. It includes a power generation element and an exterior part that houses the power generation element inside. The exterior part has a cylindrical part with openings on two opposing surfaces. It has lid terminals arranged at each of the openings. It has a resin arranged between the cylindrical part and the lid terminals. The cylindrical part and the lid terminals are integrated with the resin. The current collector of the power generation element and the lid terminal are directly connected. The width or thickness of the lid terminal is less than or equal to the width or thickness of the power generation element. The lid terminal has a convex part that protrudes outward. The resin is arranged on at least a part of the outer peripheral surface of the convex part. Secondary battery.

8. It includes a power generation element and an exterior part that houses the power generation element inside. The exterior part has a cylindrical part with openings on two opposing surfaces. It has lid terminals arranged at each of the openings. It has a resin arranged between the cylindrical part and the lid terminals. The cylindrical part and the lid terminals are integrated with the resin. The current collector of the power generation element is connected to the surface of the lid terminal facing the power generation element. The width or thickness of the lid terminal is less than or equal to the width or thickness of the power generation element. The lid terminal has a convex portion protruding outward. The resin is disposed on at least a part of the outer peripheral surface of the convex portion. Secondary battery.

9. A power generation element and an exterior portion that houses the power generation element therein. The exterior portion includes a cylindrical portion having openings on two opposing surfaces. Lid terminals disposed in respective ones of the openings. And a resin disposed between the cylindrical portion and the lid terminals. The cylindrical portion and the lid terminals are integrated with each other by the resin. The current collector of the power generation element and the lid terminal are directly connected. The width or thickness of the lid terminal is less than or equal to the width or thickness of the power generation element. The lid terminal has a protruding portion that protrudes inward from an end portion of an inner surface of the lid terminal. Secondary battery.

10. A power generation element and an exterior portion that houses the power generation element therein. The exterior portion includes a cylindrical portion having openings on two opposing surfaces. Lid terminals disposed in respective ones of the openings. And a resin disposed between the cylindrical portion and the lid terminals. The cylindrical portion and the lid terminals are integrated with each other by the resin. The current collector of the power generation element is connected to the surface of the lid terminal facing the power generation element. The width or thickness of the lid terminal is less than or equal to the width or thickness of the power generation element. The lid terminal has a protruding portion that protrudes inward from an end portion of an inner surface of the lid terminal. Secondary battery.

11. It includes a power generation element and an exterior part that houses the power generation element inside. The exterior part has a cylindrical part with openings on two opposing surfaces, lid terminals arranged at each of the openings, and a resin arranged between the cylindrical part and the lid terminals. The cylindrical part and the lid terminals are integrated with each other by the resin. The current collector of the power generation element and the lid terminals are electrically connected. The cylindrical part is composed of two metal plates and a third resin. The metal plate has a bottom surface and a protruding part that protrudes in the same direction from an end portion opposite to the bottom surface. The metal plates are stacked upside down. On each of the opposing side surfaces of the cylindrical part, the protruding parts are stacked together. The third resin is arranged so as to cover each side surface of the cylindrical part. The end portions of the overlapping metal plates are integrated with each other by the third resin. Secondary battery.

12. It includes a power generation element and an exterior part that houses the power generation element inside. The exterior part has a cylindrical part with openings on two opposing surfaces, lid terminals arranged at each of the openings, and a resin arranged between the cylindrical part and the lid terminals. The cylindrical part and the lid terminals are integrated with each other by the resin. The current collector of the power generation element and the lid terminals are electrically connected. The cylindrical part is composed of one metal plate and a third resin. The metal plate is formed in a cylindrical shape. On one side surface of the cylindrical part, the end portions of the metal plate are stacked together. The third resin is arranged so as to cover the side surface where the end portions are stacked together. The end portions of the overlapping metal plates are integrated with each other by the third resin. Secondary battery.

13. The secondary battery according to any one of claims 1 to 12, wherein the current collector is electrically connected to the lid terminal in a curved state.

14. The exterior portion has a second resin filled therein, and the cylindrical portion, the lid terminal, and the power generation element are integrated with the second resin. The secondary battery according to any one of claims 1 to 12.

15. 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 14.

16. The width or thickness of the lid terminal is less than or equal to the width or thickness of the power generation element, the thickness of the cylindrical portion > the thickness of the inner surface of the cylindrical portion ≥ the thickness of the power generation element ≥ the thickness of the lid terminal, or, the width of the cylindrical portion > the width of the inner surface of the cylindrical portion ≥ the width of the power generation element ≥ the width of the lid terminal and at least one of the above relationships is satisfied. The secondary battery according to any one of claims 1 to 15.

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