Electricity storage device

Abstract

The invention provides a power storage device with suitably improved safety. A power storage device disclosed herein is provided with: an exterior body having an opening; a sealing plate for sealing the opening part; an electrode terminal, one end of which is electrically connected to the electrode body inside the exterior body, and the other end of which is exposed to the outside of the sealing plate; and a resin insulating member that insulates the outer surface of the sealing plate from the electrode terminal. The sealing plate, the electrode terminal, and the insulating member are insert-molded, the sealing plate has a groove portion at a boundary with the insulating member on the outer surface side, and the groove portion is provided around the entire circumference of the electrode terminal.

Description

Technical Field

[0001] The present invention relates to an electric storage device. Background Art

[0002] So-called power storage devices including secondary batteries such as lithium-ion secondary batteries and capacitors such as lithium-ion capacitors are popular as power sources for driving vehicles such as BEVs (electric vehicles), HEVs (hybrid electric vehicles), and PHEVs (plug-in hybrid electric vehicles), in addition to being used as portable power sources for personal computers, mobile terminals, etc.

[0003] As an example of such an electric storage device, there can be cited an electric storage device in which a component in which a sealing plate, an electrode terminal, and an insulating component are integrated in advance by insert molding (hereinafter referred to as a "sealing plate assembly") is connected to an electrode body of a prescribed shape and accommodated in an outer casing. In this electric storage device, after the electrode body is accommodated in the outer casing, the opening portion of the outer casing is welded and joined to the sealing plate, thereby enabling manufacturing. In addition, a sealing plate assembly is manufactured by flowing molten resin in a state where the electrode terminal is inserted into the terminal mounting hole and set in a mold and cooling it. For example, an example of a sealed electric storage device (lithium-ion secondary battery) manufactured using an integrally molded component is described in Japanese Patent Application Publication No. 2021-086813.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2021-086813

[0005] According to the results of the present invention, if the electrode terminal, sealing plate and other components are arranged in the mold during insert molding, a slight gap caused by the component tolerance is generated. The molten resin is also easy to enter such a slight gap, leaking out in an undesirable place and generating resin burrs (also referred to as "burrs") after cooling. In particular, the following situation is found, that is, between the electrode terminal and the terminal mounting hole of the sealing plate, the molten resin is easy to leak out in an undesirable place, that is, the electrode terminal is fixed with a mold, etc., and burrs are also generated in a wider range. If there is such a burr, there is a concern that the burr will burn and the insulating component will burn when the sealing plate is welded to the outer body. Summary of the invention

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electric storage device with suitably improved safety.

[0007] The power storage device disclosed herein comprises: an electrode body having a positive electrode and a negative electrode; a housing having an opening and accommodating the electrode body; a sealing plate having a terminal mounting hole and sealing the opening; an electrode terminal having one end electrically connected to the electrode body inside the housing and the other end inserted through the terminal mounting hole and exposed to the outside of the sealing plate; and a resin-made insulating component that insulates the outer surface of the sealing plate from the electrode terminal. The sealing plate, the electrode terminal, and the insulating component are insert-molded, and the sealing plate has a groove at the boundary portion with the insulating component on the outer surface side, and the groove is provided around the entire circumference of the electrode terminal.

[0008] According to this structure, the generation of burrs on the outer surface of the sealing plate except for the groove portion can be suppressed. Thus, the burning of the insulating member can be appropriately suppressed, and a safer electric storage device can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 FIG. 1 is a partial cross-sectional view schematically showing a battery according to one embodiment.

[0010] Figure 2 yes Figure 1 Exploded three-dimensional diagram.

[0011] Figure 3 yes Figure 1 Schematic top view of the sealing plate.

[0012] Figure 4 It is a schematic cross-sectional view of the vicinity of the negative electrode terminal.

[0013] Figure 5 A perspective view showing the vicinity of the negative electrode terminal.

[0014] Figure 6 It is a diagram schematically showing a state of an injection molding process according to one embodiment.

[0015] Description of Reference Numerals

[0016] 10…housing; 12…external body; 12a…bottom wall; 12b…long side wall; 12c…short side wall; 12h…opening; 14…sealing plate; 14A…outer surface; 14B…inner surface; 14c…side surface; 14N…boundary portion; 14s…roughening portion; 14t…groove portion; 15…gas discharge valve; 16…liquid injection hole; 17…sealing member; 18…terminal mounting hole; 19…terminal mounting hole; 20…electrode body; 22…positive electrode sheet (positive electrode); 24…negative electrode sheet (negative electrode); 30…positive terminal (electrode terminal); 40…negative terminal (electrode terminal); 40N…boundary portion; 40s…roughening treatment portion; 41…external connection portion; 41c…side; 42…base portion; 42a…upper surface; 43…electrode body connection portion; 50…insulating component; 51…cylindrical portion; 52…flange portion; 60…sealing plate assembly; 70…diaphragm sheet; 100…electrical storage device; 200…molding mold; 210…upper mold; 212…protrusion. DETAILED DESCRIPTION

[0017] Hereinafter, the embodiments of the technology disclosed herein will be described with reference to the accompanying drawings. In addition, matters required for the implementation of the technology disclosed herein (for example, the general structure and manufacturing process of the battery that does not characterize the technology disclosed herein) other than matters specifically mentioned in this specification can be understood as design matters of a person skilled in the art based on the prior art in the art. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in the art. In addition, in the following, the same reference numerals can be marked on the components and parts that play the same role, and repeated descriptions can be omitted or simplified. In addition, in the following description, the reference numerals L, R, F, Rr, U, and D in the drawings represent left, right, front, back, top, and bottom. In addition, the reference numeral X in the drawings represents the "short side direction of the power storage device", the reference numeral Y represents the "long side direction of the power storage device", and the reference numeral Z represents the "height direction of the power storage device". However, these are just directions for the convenience of description and do not limit the installation form of the power storage device 100 at all. In addition, the expression "A to B" indicating a range in this specification means "Above A and below B".

[0018] In this specification, "electrical storage device" refers to any device that can be repeatedly charged and discharged by the movement of charge carriers between a positive electrode and a negative electrode via an electrolyte. The concept of electrical storage device includes secondary batteries such as lithium ion secondary batteries and nickel metal hydride batteries, and capacitors such as lithium ion capacitors and electric double layer capacitors.

[0019] Figure 1 It is a partial cross-sectional view of the power storage device 100 . Figure 2 is a schematic exploded perspective view of the power storage device 100. Figure 1 and Figure 2As shown, the power storage device 100 includes a housing 10, an electrode body 20, a positive terminal 30, a negative terminal 40, and an insulating member 50. The positive terminal 30 and / or the negative terminal 40 are examples of electrode terminals. Although not shown in the figure, the power storage device 100 further includes an electrolyte. Preferably, the power storage device 100 is a secondary battery, and more preferably, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery.

[0020] The housing 10 includes an outer body 12 and a sealing plate 14. The outer body 12 and the sealing plate 14 are examples of housing components constituting the housing 10. Here, the housing 10 has a flat cubic (square) shape. The housing 10 is integrated, for example, by joining (for example, welding) the sealing plate 14 to the periphery of the opening 12h of the outer body 12. The outer body 12 and the sealing plate 14 are formed, for example, of aluminum or an aluminum alloy.

[0021] The outer casing 12 is a shell that contains the electrode body 20 and the electrolyte. The outer casing 12 is a bottomed and square container having an opening 12h on the upper surface. The opening 12h is roughly rectangular. Figure 1 and Figure 2 As shown, the outer body 12 includes a bottom wall 12a, a pair of long side walls 12b extending from the bottom wall 12a and facing each other, and a pair of short side walls 12c extending from the bottom wall 12a and facing each other. The bottom wall 12a is substantially rectangular and faces the opening 12h.

[0022] Figure 3 1 is a schematic top view of the sealing plate 14. The sealing plate 14 is a plate-shaped member that seals the opening 12h of the outer body 12. Figure 3 As shown, the sealing plate 14 is roughly rectangular when viewed from above. The size of the sealing plate can be appropriately changed according to the desired battery capacity, etc., and is therefore not particularly limited. As an example, the length of the short side direction X of the sealing plate 14 can also be about 10 mm to 50 mm (preferably 20 mm to 40 mm), and the length of the long side direction Y of the sealing plate 14 can also be about 100 mm to 450 mm (preferably 120 mm to 400 mm). In addition, the thickness of the sealing plate 14 (the length in the up and down direction Z) is preferably 0.3 mm to 2 mm, and can also be 0.5 mm to 1.5 mm. The sealing plate 14 is opposite to the bottom wall 12a of the outer body 12. As shown in FIG. Figure 2 As shown, the sealing plate 14 has an outer surface 14A facing the outside and located outside the housing 10 when the opening 12h is sealed, and an inner surface 14B facing the inside of the electrical storage device 100 and facing the electrode body 20. In addition, the sealing plate 14 has terminal mounting holes 18 and 19 (see Figure 1). The terminal mounting holes 18 and 19 are provided at both ends of the sealing plate 14 in the long side direction Y. Here, the terminal mounting hole 18 is for the positive terminal 30, and the terminal mounting hole 19 is for the negative terminal 40. The sealing plate 14 is provided with a gas discharge valve 15 and a liquid injection hole 16 for injecting an electrolyte. The gas discharge valve 15 is a thin-walled portion configured to rupture when the pressure in the housing 10 becomes greater than a predetermined value and discharge the gas in the housing 10 to the outside. The liquid injection hole 16 is sealed by a sealing member 17.

[0023] In the housing 10, in addition to accommodating the electrode body 20 as described above, an electrolyte is also accommodated. As the electrolyte, an electrolyte used in a conventionally known battery can be used without particular limitation. As an example, a non-aqueous electrolyte in which a supporting salt is dissolved in a non-aqueous solvent can be used. As an example of a non-aqueous solvent, carbonate-based solvents such as ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate can be cited. As an example of a supporting salt, LiPF 6 And other fluorine-containing lithium salts.

[0024] like Figure 2 As shown, the power storage device 100 includes a sealing plate assembly 60. The sealing plate assembly 60 is an assembly component in which the electrode terminal (positive terminal 30 and negative terminal 40) and the insulating component 50 are assembled on the sealing plate 14 by insert molding (integrated molding). The electrode terminals are firmly fixed to the sealing plate 14 by the insulating component 50. Thus, the electrode terminal is assembled to the sealing plate 14 without riveting. In addition, the electrode terminal is fixed to the sealing plate 14 by the insulating component 50 without direct contact. The sealing plate 14 and the electrode terminal are in close contact with the insulating component 50, so that the terminal mounting holes 18 and 19 are sealed by the insulating component 50. That is, the electrode terminal is fixed to the sealing plate 14 in an immovable manner by the insulating component 50.

[0025] like Figure 1 As shown, the electrode body 20 is contained inside the outer body 12. The electrode body 20 is contained inside the outer body 12, for example, in a state covered by an insulating film or the like not shown in the figure. Here, the electrode body 20 is a wound electrode body in which a strip-shaped positive electrode sheet 22 and a strip-shaped negative electrode sheet 24 are stacked in an insulated state separated by two strip-shaped separator sheets 70 and wound in the long side direction with the winding axis as the center. However, the electrode body 20 may also be a stacked electrode body in which rectangular positive electrode sheets and rectangular negative electrode sheets are alternately stacked with rectangular separator sheets. Alternatively, it may be a fan-shaped stacked electrode body formed by sandwiching a plurality of positive electrode sheets and a plurality of negative electrode sheets between separator sheets folded into a fan shape.

[0026] The positive electrode sheet 22 includes a strip-shaped positive electrode current collector 22c and a positive electrode active material layer 22a fixed on at least one surface of the positive electrode current collector 22c (see Figure 1). The various components constituting the positive electrode sheet 22 can use previously known materials that can be used in general batteries (for example, lithium-ion secondary batteries) without particular restrictions. For example, the positive electrode collector 22c is preferably composed of a conductive metal such as aluminum, aluminum alloy, nickel, stainless steel, etc. The positive electrode active material layer 22a contains a positive electrode active material that can reversibly absorb and release charge carriers (for example, lithium transition metal composite oxides such as lithium nickel cobalt manganese composite oxide). In addition, the positive electrode active material layer 22a may also contain any component other than the positive electrode active material, for example, a conductive material, a binder, various additives, etc.

[0027] The negative electrode sheet 24 includes a strip-shaped negative electrode current collector 24c and a negative electrode active material layer 24a fixed to at least one surface of the negative electrode current collector 24c (see Figure 1 ). The various components constituting the negative electrode sheet 24 can use previously known materials that can be used in general batteries (for example, lithium-ion secondary batteries) without particular restrictions. For example, the negative electrode collector 24c is preferably composed of a conductive metal such as copper, copper alloy, nickel, stainless steel, etc. The negative electrode active material layer 24a contains a negative electrode active material (for example, a carbon material such as graphite) that can reversibly absorb and release charge carriers. In addition, the negative electrode active material layer 24a may also contain any component other than the negative electrode active material, for example, a conductive material, a binder, a dispersant, various additives, etc.

[0028] The diaphragm sheet 70 is an insulating sheet formed with a plurality of tiny through holes through which charge carriers can pass. The diaphragm sheet 70 is, for example, made of a porous resin substrate. As the resin substrate, for example, a sheet (film) made of a resin such as polyethylene (PE), polypropylene (PP), polyester, polyamide, cellulose, etc. is exemplified. The diaphragm sheet 70 may be a single-layer structure, or a structure in which two or more porous resin sheets having different properties and characteristics (thickness, porosity, etc.) are stacked (for example, a three-layer structure in which PP layers are stacked on both sides of a PE layer). In addition, the diaphragm sheet 70 may also have a heat-resistant layer (Heat Resistant Layer: HRL layer) composed of ceramic particles, etc. on its surface.

[0029] like Figure 1 As shown, the electrode body 20 housed in the outer casing 12 is arranged so that one end of the positive electrode collector 22c is near the left end in the long side direction Y of the electrical storage device 100, and one end of the negative electrode collector 24c is near the right end in the long side direction Y of the electrical storage device 100. In addition, the positive terminal 30 is attached to one end of the sealing plate 14 in the long side direction Y ( Figure 1 The negative terminal 40 is attached to the other end of the sealing plate 14 in the longitudinal direction Y ( Figure 1In the power storage device 100, for the positive terminal 30 and the negative terminal 40, one end is electrically connected to the electrode body 20 as described above inside the housing 10, and the other end is inserted through the terminal mounting holes 18 and 19 and exposed to the outside of the sealing plate 14. In addition, the positive terminal 30 is preferably formed of a metal with excellent conductivity, such as aluminum or an aluminum alloy. In addition, the negative terminal 40 is preferably formed of a metal with excellent conductivity, such as copper or a copper alloy.

[0030] Figure 4 : is a schematic cross-sectional view of the vicinity of the negative terminal. Figure 2 and Figure 4 As shown, the negative terminal 40 has an external connection portion 41, a pedestal portion 42, and an electrode body connection portion 43. The negative terminal 40 may also have an unillustrated shaft portion between the external connection portion 41 and the pedestal portion 42. In the following description, the negative terminal 40 is used as an electrode terminal and the insulating component 50 on the negative terminal 40 side is used as an insulating component. However, this description is not intended to limit the application of the technology disclosed herein to the structure on the negative terminal side. That is, the technology disclosed herein includes a form of a positive terminal having a structure substantially the same as the negative terminal 40 described below.

[0031] like Figure 4 As shown, the external connection portion 41 is configured to be sized to be inserted into the terminal mounting hole 19. The upper end of the external connection portion 41 is configured to be exposed to the outside of the outer shell 10. The external connection portion 41 is provided above the base portion 42. Here, the base portion 42 is formed in a plate shape. The base portion 42 is configured to be inside the outer shell 10. The outer shape of the base portion 42 is configured to be larger than the terminal mounting hole 19. The electrode body connection portion 43 is configured to be inside the outer shell 10. The electrode body connection portion 43 extends downward from one end of the base portion 42. The end of the electrode body connection portion 43 is connected to the electrode body 20 (more specifically, the negative electrode sheet 24) inside the outer shell 10. In addition, in Figure 4 In the example shown, the external connection portion 41 is configured to be inserted through the terminal mounting hole 19 , but the structure of the electrode terminal is not limited thereto. For example, the electrode terminal may be configured to be configured to be inserted through the terminal mounting hole 19 by the electrode body connection portion 43 and the seat portion 42 .

[0032] The insulating component 50 is arranged between the sealing plate 14 and the positive terminal 30 and the negative terminal 40 to prevent conduction between the sealing plate 14 and the positive terminal 30 and the negative terminal 40. The insulating component 50 is composed of a resin material as a main component. As a resin material, for example, fluorinated resins such as perfluoroalkoxy fluororesin (PFA), polyphenylene sulfide resin (PPS), aliphatic polyamide, etc. can be cited. Among them, it is preferred that the insulating component 50 is composed of PPS as a main component. In addition to the above-mentioned resin materials such as PFA and PPS, inorganic fillers and the like can also be added to the insulating component 50. As an inorganic filler, an insulating inorganic oxide or glass can be used. Specifically, as an inorganic filler, aluminum oxide, magnesium oxide, silicon dioxide, titanium dioxide, etc. can be cited. In addition, "A is composed of B as a main component" means that among the components constituting A, B is the largest component based on weight.

[0033] like Figure 4 As shown, the insulating component 50 has a cylindrical portion 51 and a flange portion 52. The cylindrical portion 51 and the flange portion 52 are formed as a whole. The cylindrical portion 51 is located between the external connection portion 41 and the terminal mounting hole 19. The cylindrical portion 51 insulates the negative terminal 40 from the terminal mounting hole 19. The upper end portion of the cylindrical portion 51 is exposed to the outside of the housing 10. The flange portion 52 extends from the cylindrical portion 51 in the horizontal direction along the inner surface 14B of the sealing plate 14. The flange portion 52 insulates the inner surface 14B of the sealing plate 14 from the base portion 42. The outer shape of the flange portion 52 is configured to be larger than the outer shape of the base portion 42.

[0034] Figure 5 4 is an enlarged perspective view of the periphery of the negative electrode terminal 40. Figure 3 to Figure 5As shown, in the storage device 100 disclosed here, a groove portion 14t is provided at the boundary portion 14N with the insulating component 50 on the outer surface side of the sealing plate 14. The groove portion 14t is provided around the entire circumference of the electrode terminal (positive terminal 30 and negative terminal 40). According to this structure, a storage device 100 with higher safety can be provided. Although the details will be described later, insert molding is implemented by setting each component in a mold and pouring molten resin. At this time, there are slight gaps between the components caused by component tolerances. Molten resin is also easy to enter such slight gaps. Moreover, it leaks out in undesirable places and generates resin burrs (also referred to as "burrs" for short) after cooling. In particular, between the electrode terminal and the terminal mounting holes 18 and 19 of the sealing plate 14, the molten resin is easy to leak out in undesirable places, and even if the electrode terminal is fixed by a mold, burrs may be generated in a wider range. If such burrs exist, there is a concern that the burrs may burn and further burn the insulating component 50 when the sealing plate 14 and the outer body 12 are welded. Therefore, in the electrical storage device 100 disclosed herein, as described above, the sealing plate 14 has a groove portion 14t. By providing the groove portion 14t, there is room for the molten resin to flow in, and the molten resin can be prevented from crossing the groove portion 14t and spreading to the outer surface 14A of the sealing plate 14. Thus, the generation of burrs in a wider range of the outer surface 14A of the sealing plate 14 after insert molding is suppressed. According to this structure, the insulating component 50 can be prevented from burning, so that a safer electrical storage device 100 can be provided.

[0035] The groove portion 14t only needs to be configured so that even if the molten resin flows in, it will not go over the groove portion 14t and produce burrs on the outer surface 14A of the sealing plate 14. The groove portion 14t is located on the outer surface 14A side of the sealing plate 14. The groove portion 14t is a recessed portion that is recessed from the outer surface 14A of the sealing plate 14 toward the inner surface 14B. Here, the cross-section of the groove portion 14t is rectangular. Here, the side wall of the groove portion 14t is perpendicular to the bottom surface of the groove portion 14t. However, the cross-section of the groove portion 14t may also be polygonal or semicircular.

[0036] In a plan view, the groove 14t is continuously formed in a substantially annular shape along the boundary 14N between the sealing plate 14 and the insulating member 50. Figure 5 As shown, the groove 14t is formed in a substantially rectangular shape around the entire circumference of the electrode terminal (here, the negative terminal 40). This can prevent the molten resin from leaking from between the electrode terminal and the terminal mounting hole 19 and causing burrs at undesirable positions. The groove 14t is substantially uniformly arranged with the center of the electrode terminal as a reference.

[0037] Although not particularly limited, the groove portion 14t is preferably configured such that when the groove width is set to Xmm and the groove depth is set to Ymm, the total of the groove width X and the groove depth Y is greater than 1mm. That is, the cross-sectional shape of the groove portion 14t is preferably configured to satisfy the formula: (X+Y)≥1. Thus, even if the molten resin leaks out, it will not go over the groove portion 14t, thereby suppressing the generation of burrs on the outer surface 14A of the sealing plate 14. The total of the groove width X and the groove depth Y is preferably less than 3mm, for example, and may also be less than 2.5mm. Thus, the strength of the sealing plate 14 is fully ensured.

[0038] The groove depth Y of the groove portion 14t has a predetermined depth, so that even if the molten resin leaks out, it can be appropriately accommodated. Although not particularly limited, it is preferred that the groove depth Y of the groove portion 14t is 0.1mm or more. According to the results of the present invention, the thickness tolerance of the sealing plate 14 is less than 0.1mm. Therefore, by setting the groove depth Y to be more than 0.1mm, it is possible to fully suppress the molten resin from leaking out of the outer surface 14A of the sealing plate 14 over the groove portion 14t. In particular, by using a mold having a protrusion as described later to implement insert molding, it is possible to appropriately suppress the molten resin from overflowing from the groove portion 14t. The upper limit of the groove depth Y of the groove portion 14t is not particularly limited, but it is preferably less than 1 / 2 of the thickness t of the sealing plate 14, and it can also be less than 1 / 3. More specifically, it is preferably less than 1mm, can be less than 0.7mm, and can also be less than 0.5mm. In addition, the groove depth Y refers to the length of the groove portion 14t in the vertical direction Z from the upper end to the lower end.

[0039] By having a predetermined length of the groove width X of the groove portion 14t, it is possible to suppress leakage of the resin from the outer surface 14A of the sealing plate 14. The groove width X is preferably, for example, greater than 0.1 mm, and may also be greater than 0.5 mm. Thus, it is possible to fully ensure space for accommodating the molten resin. On the other hand, when the groove portion 14t is too wide, there is concern that the strength of the sealing plate 14 is reduced and the adhesion strength between the electrode terminal and the sealing plate 14 is reduced. From this point of view, the groove width X is preferably less than 2 mm, and more preferably less than 1.5 mm. In addition, the groove width X is the length of the short side direction X and the length of the long side direction Y.

[0040] In a preferred embodiment, the insulating member 50 is not disposed on the outer surface 14A of the sealing plate 14 (more specifically, the outer surface 14A excluding the groove portion 14t). This can appropriately prevent the insulating member 50 from being burned during welding or the like. The insulating member 50 may or may not be disposed in the groove portion 14t. Figure 4As shown, the insulating member 50 need not be disposed in the groove portion 14t. For example, by insert molding using a mold having a protrusion described later, the electrical storage device 100 without the insulating member 50 disposed in the groove portion 14t can be manufactured.

[0041] It is preferred that at least a portion of the surface of the portion of the sealing plate 14 that contacts the insulating member 50 is roughened. Roughening is a surface treatment that increases the surface area and improves the anchoring effect by forming irregularities on the surface, thereby improving the bonding and adhesion with the insulating member 50. Roughening can be performed, for example, by laser irradiation, sandblasting, etc. The portion of the sealing plate 14 that has been roughened constitutes a roughened portion 14s (see Figure 4 ) The sealing plate 14 preferably has a roughened portion 14 s at at least a portion of a boundary portion 14N with the insulating member 50 .

[0042] Preferably, the roughening treatment portion 14s is configured to cut off the leakage path of the electrolyte (i.e., the path of the electrolyte leaking from the inside of the storage device 100). For example, here, the roughening treatment portion 14s is set to the inner surface 14B of the periphery of the terminal mounting hole 19, and the surface of the side 14c that constitutes the terminal mounting hole 19 and contacts the insulating component 50. Preferably, the roughening treatment portion 14s in the inner surface 14B of the sealing plate 14 is arranged in the entire area in a manner surrounding the terminal mounting hole 19. Although not particularly limited, the width W1 of the roughening treatment portion 14s in the inner surface 14B of the sealing plate 14 is preferably greater than 1 mm, and more preferably greater than 3 mm. As a result, the close contact strength between the sealing plate 14 and the insulating component 50 becomes higher, so that it can be sealed more firmly. More preferably: the sealing plate 14 has a roughening treatment portion 14s in the entire area of ​​the surface in contact with the insulating component 50.

[0043] In addition, although not particularly limited, it is preferred that at least a portion of the surface of the portion of the electrode terminal that contacts the insulating member 50 is roughened similarly to the roughened portion 14s of the sealing plate 14. Figure 4 As shown, the roughened portion of the electrode terminal (here, the negative electrode terminal 40 ) constitutes a roughened portion 40s. It is preferred that the negative electrode terminal 40 has the roughened portion 40s at least in a portion of a boundary portion 40N with the insulating member 50 .

[0044] Similar to the above-mentioned roughening treatment part 14s, the roughening treatment part 40s of the negative terminal 40 is preferably configured to cut off the leakage path of the electrolyte. For example, here, the roughening treatment part 40s is arranged on the side 41c of the external connection part 41 and the upper surface 42a of the base part 42. The length L1 of the roughening treatment part 40s arranged on the side 41c of the external connection part 41 is preferably set along the side 41c with a length of more than 1mm, and can also be set with a length of more than 3mm. The length L2 of the roughening treatment part 40s arranged on the upper surface 42a of the base part 42 is preferably set along the upper surface 42a with a length of more than 1mm, and can also be set with a length of more than 3mm. As a result, the adhesion strength between the electrode terminal and the insulating component 50 is increased, so that it can be sealed more firmly. More preferably, the electrode terminal has a roughening treatment part 40s in the entire area of ​​the surface in contact with the insulating component 50.

[0045] The sealing plate 14 and the electrode terminal may both have the roughened portion 14s and the roughened portion 40s. In this way, the sealing plate 14, the electrode terminal, and the insulating member 50 are more firmly sealed, thereby realizing a safer electrical storage device 100.

[0046] <Method for manufacturing electric storage device>

[0047] Next, an example of a method for manufacturing the power storage device 100 will be described. The manufacturing method disclosed herein includes, for example, (1) a preparation step and (2) a sealing step. Here, (1) the preparation step includes (1A) an insert molding step.

[0048] (1) In the preparation step, at least the outer casing 12, the sealing plate 14, the positive electrode terminal 30, the negative electrode terminal 40, and the electrode assembly 20 are prepared. Here, the sealing plate 14 is prepared to have grooves 14t around the terminal mounting holes 18 and 19.

[0049] (1A) In the insert molding process, the sealing plate 14, the positive terminal 30, the negative terminal 40, and the insulating component 50 are integrated to form a component part (e.g., a sealing plate assembly 60). The sealing plate assembly 60 can be made by insert molding the sealing plate 14, the positive terminal 30, the negative terminal 40, and the insulating component 50. Thus, the number of components can be reduced, and a conduction path can be easily formed compared to the previous method of using rivets. Insert molding can be performed according to a previously known method, such as described in Japanese Patent Application Publication No. 2021-086813, Japanese Patent Application Publication No. 2021-086814, Japanese Patent No. 03986368, Japanese Patent No. 6648671, etc. For example, the insert molding process can be performed using a molding die having an upper mold and a lower mold by a method including a component setting process, a positioning process, an upper mold setting process, an injection molding process, an upper mold releasing process, and a component removing process.

[0050] In the component setting process, after the positive terminal 30 and the negative terminal 40 are respectively inserted into the terminal mounting holes 18 and 19 of the sealing plate 14, the sealing plate 14 is installed on the lower mold. In the positioning process, the positive terminal 30 and the negative terminal 40 are respectively positioned and fixed. In the upper mold setting process, the upper mold is installed to clamp the sealing plate 14 and the positive terminal 30 and the negative terminal 40 in the upper and lower directions together with the lower mold. In the injection molding process, the molding mold is first heated. Next, molten resin is injected into the molding mold. The molten resin flows from the upper mold to the lower mold through the terminal mounting holes 18 and 19. Thereafter, the molding mold and the molded product are cooled. Thus, the insulating component 50, the sealing plate 14 and the electrode terminal are integrated. In the upper mold release process, the upper mold is separated from the lower mold. In the component removal process, the molded product is removed from the lower mold.

[0051] Figure 6 Schematically shows the injection molding process. Figure 6As shown, the upper mold 210 of the molding die 200 may also have a protrusion 212 that can enter the above-mentioned groove 14t. By performing the injection molding process in a state where the protrusion 212 of the upper mold 210 enters the groove 14t, it is possible to suppress the injected molten resin from overflowing from the groove 14t and adhering to the outer surface 14A of the sealing plate 14. Thus, the generation of burrs can be further reduced. Although not particularly limited, the length of the protrusion 212 in the vertical direction Z is 0.05mm to 0.3mm (preferably 0.1mm). As mentioned above, the thickness tolerance of the sealing plate 14 is less than 0.1mm, so as long as the protrusion 212 has a length within the above-mentioned range, the thickness tolerance of the sealing plate 14 can be coped with. Therefore, the injection molding process can be performed in a state where the upper mold 210 is in close contact with the sealing plate 14, and the leakage of the molten resin can be more appropriately suppressed.

[0052] (2) In the sealing process, the outer body 12 is sealed with the sealing plate assembly 60 while the electrode body 20 and the electrolyte are contained in the outer body 12. Specifically, first, the electrode body connection portion 43 of the sealing plate assembly 60 is connected to the electrode body 20. Next, the electrode body 20 is inserted from the opening 12h of the outer body 12, and the sealing plate 14 of the sealing plate assembly 60 is joined to the periphery of the opening 12h of the outer body 12 by laser welding or the like. Moreover, the electrical storage device 100 is sealed by injecting the electrolyte from the injection hole 16 and plugging the injection hole 16 with the sealing member 17. The electrical storage device 100 can be manufactured as described above. In the electrical storage device 100 disclosed herein, the generation of burrs is reduced by having the groove 14t of the sealing plate 14. Therefore, even if welding is performed in the sealing process, the burrs will not be burned. Therefore, a more excellent electrical storage device 100 can be provided.

[0053] <Battery Application>

[0054] The power storage device 100 can be used for various purposes, but can be used as a power source (driving power source) for a motor mounted on a vehicle such as a passenger car or a truck, for example. The type of vehicle is not particularly limited, but examples thereof include a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), and a battery electric vehicle (BEV). Since safety is improved, the power storage device 100 can be used to construct a battery pack.

[0055] Several embodiments of the present invention have been described above, but the above embodiment is only an example. In addition, the present invention can be implemented in various forms. The present invention can be implemented based on the contents disclosed in this specification and the technical common sense in the field. The technology described in the claims includes various deformations and changes to the above-mentioned exemplified embodiments. For example, part of the above-mentioned embodiment can be replaced by other deformation methods, and other deformation methods can be added to the above-mentioned embodiment. In addition, as long as it is not stated that the technical feature is necessary, it can be appropriately deleted.

[0056] As described above, as specific aspects of the technology disclosed here, aspects described in the following items can be cited.

[0057] Item 1: A power storage device, wherein the power storage device comprises: an electrode body having a positive electrode and a negative electrode; a shell having an opening and accommodating the electrode body; a sealing plate having a terminal mounting hole and sealing the opening; an electrode terminal, one end of which is electrically connected to the electrode body inside the shell and the other end of which is inserted through the terminal mounting hole and exposed to the outside of the sealing plate; and a resin-made insulating component that insulates the outer surface of the sealing plate from the electrode terminal, the sealing plate, the electrode terminal and the insulating component are insert-molded, the sealing plate has a groove at a boundary portion with the insulating component on the outer surface side, and the groove is arranged around the entire circumference of the electrode terminal.

[0058] Item 2: The power storage device according to Item 1, wherein, when the groove width is X mm and the groove depth is Y mm, the total of the groove width X and the groove depth Y of the groove portion is 1 mm or more.

[0059] Item 3: The electrical storage device according to Item 2, wherein the groove depth Y is 0.1 mm or more.

[0060] Item 4: The electrical storage device according to any one of Items 1 to 3, wherein the sealing plate has a roughened portion at least partially at a boundary with the insulating member.

[0061] Item 5: The electrical storage device according to any one of Items 1 to 4, wherein the electrode terminal has a roughened portion at least partially at a boundary with the insulating member.

Claims

1. An electric storage device, wherein: The power storage device comprises: an electrode body having a positive electrode and a negative electrode; an outer casing having an opening and accommodating the electrode body; A sealing plate having a terminal mounting hole and sealing the opening; an electrode terminal having one end electrically connected to the electrode body inside the outer casing and the other end inserted through the terminal mounting hole and exposed to the outside of the sealing plate; and A resin insulating member is provided to insulate the outer surface of the sealing plate from the electrode terminal. The sealing plate, the electrode terminal and the insulating component are insert-molded. The sealing plate has a groove portion at a boundary portion with the insulating member on the outer surface side. The groove portion is provided around the entire circumference of the electrode terminal.

2. The power storage device according to claim 1, wherein When the groove width is X mm and the groove depth is Y mm, the total of the groove width X and the groove depth Y of the groove portion is 1 mm or more.

3. The power storage device according to claim 2, wherein: The groove depth Y is greater than or equal to 0.1 mm.

4. The power storage device according to any one of claims 1 to 3, wherein The sealing plate has a roughened portion at least partially at a boundary with the insulating member.

5. The electrical storage device according to any one of claims 1 to 3, wherein The electrode terminal has a roughened portion at least partially at a boundary with the insulating member.

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