Electricity storage device and method for manufacturing same

Abstract

The invention provides a power storage device and a method for manufacturing the same, which can avoid or reduce the occurrence of resin burrs of an insulating resin member integrally formed with a current collector terminal and a housing member on the outer peripheral edge of an external connection part of the current collector terminal. A power storage device is provided with: a case cover having a terminal insertion hole; a collector terminal having a hole insertion portion inserted into the terminal insertion hole and an external connection portion disposed on the front surface side of the housing member; and an insulating resin member integrally formed with the collector terminal and the housing member. The insulating resin member is provided with an outer peripheral side insulating resin part surrounding the outer peripheral edge of the external connection part, and a rear surface side insulating resin part connecting the rear surface of the external connection part, the hole outer edge part, the hole peripheral part, and the hole insertion part, and a hollow part penetrating through the rear surface of the external connection part is formed in the rear surface side insulating resin part. An endless belt-shaped sealing part is formed on the back surface of the external connection part along the outer edge part of the hollow part.

Description

Technical Field

[0001] The disclosed technology relates to an electric storage device and a method for manufacturing the same. Background Art

[0002] For example, Patent Document 1 discloses a sealed storage battery in which an insulating resin member is integrally molded (insert-molded) with a current collector terminal and a case member so as to fill a space between the current collector terminal and a terminal insertion hole of the case member.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-86813 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, when the current collector terminal is formed by bending the external connection portion disposed on the surface side of the shell member relative to the hole insertion portion inserted into the terminal insertion hole of the shell member, the bending angle of the external connection portion relative to the hole insertion portion is easily deviated. Therefore, there is a problem that during injection molding in which the insulating resin member, the current collector terminal and the shell member are integrally formed, the molten resin of the insulating resin member enters into the gap between the surface of the external connection portion having the deviated bending angle and the mold abutment portion, and resin burrs of the insulating resin member are generated on the surface side of the external connection portion.

[0008] The present technology is made in view of this problem and provides a power storage device and a manufacturing method thereof, which can avoid or reduce the occurrence of resin burrs of an insulating resin member integrally formed with a collector terminal and a case member on the surface side of an external connection portion of the collector terminal.

[0009] Solutions to Solve Problems

[0010] (1) One method of the disclosed technology for solving the above-mentioned problems is an electric storage device, wherein the electric storage device comprises: a shell member having a terminal insertion hole; a collector terminal having a hole insertion portion and an external connection portion, the hole insertion portion being inserted into the terminal insertion hole along the front-back direction of the shell, the external connection portion being arranged on the surface side of the shell member and being bent relative to the hole insertion portion; and an insulating resin member connected to the collector terminal and the hole insertion portion in a manner that the hole insertion portion and the external connection portion are connected to the hole outer edge portion and the hole periphery portion of the terminal insertion hole. The shell component is formed in one piece, and the insulating resin component includes: an outer peripheral insulating resin part, which surrounds the outer peripheral edge of the external connection part on the entire circumference; and a back side insulating resin part, which connects the back side of the external connection part, the hole outer edge part, the hole surrounding part and the hole insertion part, and a hollow part (Japanese: meat-shaped part) is formed on the back side insulating resin part, which passes through from the back side of the back side insulating resin part along the front and back direction of the shell to the back side of the external connection part, and an annular sealing part is formed on the back side of the external connection part along the outer edge of the hollow part.

[0011] (2) The power storage device described in (1) may be a power storage device wherein a surface of the external connection portion and a surface of the outer peripheral insulating resin portion are formed on the same plane, and a groove portion is formed on a boundary line between the external connection portion and the outer peripheral insulating resin portion.

[0012] (3) The method for manufacturing an electrical storage device described in (1) or (2) may be a method for manufacturing an electrical storage device, wherein a molding die having a fixed mold and a movable mold is used, the fixed mold and the movable mold respectively having a mold abutting portion abutting against the collector terminal and the shell member and a cavity portion filled with molten resin of the insulating resin member, the movable mold having a pressing portion for pressing the external connection portion toward the shell surface side, and the method for manufacturing an electrical storage device comprises the following steps: a step of arranging the collector terminal and the shell member on the molding die in a manner abutting against the mold abutting portion; and a step of filling the cavity portion with the molten resin while pressing the back side of the external connection portion toward the shell surface side on the inner peripheral side of the sealing portion by the pressing portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is an exploded perspective view of one mode (this example) of the power storage device according to the present embodiment.

[0014] Figure 2 yes Figure 1 The A portion shown is a partial perspective view when viewed obliquely from the rear side of the housing.

[0015] Figure 3 yes Figure 1 BB cross-sectional view shown.

[0016] Figure 4 yes Figure 1 A BB cross-sectional view of a comparative example of the electric storage device shown.

[0017] Figure 5 yes Figure 1 sectional view of a molding die used in the method for manufacturing an electric storage device shown.

[0018] Figure 6 yes Figure 1 A cross-sectional view taken along line BB of a modified example of the electric storage device shown. DETAILED DESCRIPTION

[0019] <Description of this power storage device>

[0020] Hereinafter, one mode (this embodiment) of the electric storage device 10 according to the embodiment of the above-disclosed technology will be described in detail with reference to the drawings. Figure 1 An exploded perspective view showing one mode (this example) of the power storage device according to the present embodiment. Figure 2 express Figure 1 The A portion shown is a partial perspective view when viewed obliquely from the rear side of the housing. Figure 3 express Figure 1 BB cross-sectional view shown.

[0021] like Figure 1 to Figure 3 As shown, one mode (this embodiment) of the power storage device 10 of the embodiment of the disclosed technology includes a case cover (an example of a "case member" of the present disclosure) 4, a collector terminal 3, and an insulating resin member 5 integrally formed (insert-molded) with the collector terminal 3 and the case cover 4. The case cover 4 has a pair of terminal insertion holes 41 at both ends in the longitudinal direction. The collector terminal 3 has a hole insertion portion 31 and an external connection portion 32, and the hole insertion portion 31 is arranged along the case front-back direction (in the case back direction). Figure 3 The external connection portion 32 is arranged on the surface side of the shell cover 4 and is formed by bending relative to the hole insertion portion 31. The external connection portion 32 is formed to be rectangular when viewed from the shell surface side CF (the upper side in the figure) so that it can be connected to a bus bar, etc., which is not shown. The terminal insertion hole 41 is formed to a size that allows the hole insertion portion 31 and the external connection portion 32 to be inserted along the front and back directions of the shell. Here, the external connection portion 32 is formed by bending at a right angle relative to the hole insertion portion 31, but it is not necessarily limited to this.

[0022] In addition, the insulating resin member 5 is integrally formed (insert-molded) with the collector terminal 3 and the case cover 4 in such a manner that the hole insertion portion 31 and the external connection portion 32 are connected to the hole outer edge portion 411 and the hole surrounding portion 412 of the terminal insertion hole 41. In addition, the insulating resin member 5 includes a back side insulating resin portion 51, which connects the back side 321 of the external connection portion 32, the hole outer edge portion 411, the hole surrounding portion 412, and the hole insertion portion 31. The hole insertion portion 31 of the collector terminal 3 and the hole surrounding portion 412 of the case cover 4 are formed with, for example, annular roughened surfaces 311 and 413 with an arithmetic mean roughness of 30 to 500 nm, and the roughened surfaces 311 and 413 constitute a sealing portion SR with the insulating resin member 5.

[0023] In addition, the insulating resin member 5 includes an outer circumferential insulating resin portion 53 that surrounds the outer circumferential edge 322 of the external connection portion 32 on the case surface side CF of the case cover 4 over the entire circumference. In addition, the surface 323 of the external connection portion 32 on the case surface side CF and the surface 531 of the outer circumferential insulating resin portion 53 on the case surface side CF are formed on the same plane. Furthermore, a resin injection portion (gate portion) 54 of the insulating resin member 5 is formed at a position close to the center of the case on the outer circumferential insulating resin portion 53 so as to protrude toward the center of the case.

[0024] Here, the present power storage device 10 comprises: an electrode body 1; a case body 2 having an opening 21 and accommodating the electrode body 1; a collector terminal 3 electrically connected to the electrode body 1; a case cover 4 having a terminal insertion hole 41, holding the collector terminal 3 inserted in the terminal insertion hole 41 and holding the electrode body 1 via the collector terminal 3, and sealing the opening 21 of the case body 2; and an insulating resin member 5 integrally formed (insert-molded) with the collector terminal 3 and the case cover 4 in a manner that connects the hole insertion portion 31 and the external connection portion 32 of the collector terminal 3 with the hole outer edge portion 411 and the hole surrounding portion 412 of the terminal insertion hole 41. However, the present power storage device 10 may not necessarily be limited to the above-mentioned structure. For example, the terminal insertion hole 41 may also be formed in the case body 2. In the present embodiment, the case of the power storage device 10 is constituted by the case body 2 and the case cover 4.

[0025] In addition, the present power storage device 10 refers to all power storage devices that can extract electric energy, such as primary batteries, secondary batteries, double-layer capacitors, etc. In addition, the electrode body 1 is a known electrode body formed by stacking a positive electrode body having an active material layer of a positive electrode and a negative electrode body having an active material layer of a negative electrode through a separator. The shell body 2 is a bottomed cylindrical body with an opening 21 formed at the upper end, for example, made of aluminum or an aluminum alloy. The collector terminal 3 is composed of a positive collector terminal 3a connected to the positive side of the electrode body 1 and a negative collector terminal 3b connected to the negative side of the electrode body 1. The positive collector terminal 3a is, for example, made of aluminum or an aluminum alloy, and the negative collector terminal 3b is, for example, made of copper or a copper alloy. The shell cover 4 is, for example, made of aluminum or an aluminum alloy and is formed into a flat plate-shaped cover. The shell cover 4 is formed with a terminal insertion hole 41 for inserting the collector terminal 3, a known safety valve 42, and an injection hole 43 for injecting electrolyte.

[0026] In addition, the insulating resin member 5 has a thermoplastic resin material NJ having heat resistance, formability, insulation, sealing, resistance to electrolyte, etc. Here, the thermoplastic resin material NJ uses PPS resin (polyphenylene sulfide resin), but it is not limited to this. In addition, the insulating resin member 5 may also contain reinforcing members such as glass fibers or elastomers in the thermoplastic resin material NJ.

[0027] As described above, the current collector terminal 3 includes the hole insertion portion 31 inserted into the terminal insertion hole 41 along the front-back direction of the case and the external connection portion 32 arranged on the surface side of the case cover 4 and formed by bending relative to the hole insertion portion 31. Therefore, for each current collector terminal 3, the bending angle of the external connection portion 32 relative to the hole insertion portion 31 is easily varied. Therefore, the back side insulating resin portion 51 is formed with a hollow portion 52 that penetrates from the back side 511 of the back side insulating resin portion 51 to the back side 321 of the external connection portion 32 along the front-back direction of the case. Therefore, during injection molding to integrally mold the insulating resin member 5 with the current collector terminal 3 and the case cover 4, the mold in the mold-clamped state can press the area on the inner peripheral side of the hollow portion 52 in the back side 321 of the external connection portion 32 toward the case surface side CF, so that the gap between the surface 323 of the external connection portion 32 and the mold contact portion is zero or minimized. As a result, the molten resin YJ of the insulating resin member 5 cannot enter the gap between the surface 323 of the external connection part 32 and the mold abutment portion, and the generation of resin burrs JB extending from the outer peripheral insulating resin part 53 to the surface 323 of the external connection part 32 can be avoided or reduced.

[0028] In addition, the hollow portion 52 is formed in a rectangular shape when viewed from the case back side CB, and a roughened surface 324 in an annular shape is formed along the outer edge 521 of the hollow portion 52 on the back side 321 of the external connection portion 32. The roughened surface 324 is formed in an annular shape with an arithmetic mean roughness of 30 to 500 nm, for example, and constitutes a sealing portion SR with the insulating resin member 5. Therefore, the sealing performance around the hollow portion 52 of the back side insulating resin portion 51 can be ensured.

[0029] In contrast, Figure 4 express Figure 1 BB cross-sectional view of a comparative example of the power storage device shown. Figure 4 As shown, in the electric storage device 10C of the comparative example, the back side insulating resin portion 51C connecting the back side 321 of the external connection portion 32, the hole outer edge portion 411, the hole surrounding portion 412 and the hole insertion portion 31 is not formed. Figure 2 , Figure 3 The hollow portion 52 shown. In addition, the roughened surface 324 (sealing portion SR) in the form of an annular belt is not formed along the outer edge 521 of the hollow portion 52 on the back surface 321 of the external connection portion 32. The electric storage device 10C of the comparative example is the same as the electric storage device 10 of the present embodiment except for the hollow portion 52 and the roughened surface 324 (sealing portion SR), and therefore, the same reference numerals are given to the same parts.

[0030] In the electric storage device 10C of the comparative example, the hollow portion 52 is not formed in the back side insulating resin portion 51C. Therefore, even if the bending angle of the external connection portion 32 relative to the hole insertion portion 31 deviates, during the injection molding of the insulating resin member 5C, the current collector terminal 3 and the case cover 4 as a whole, the mold in the mold-clamped state cannot directly press the back side 321 of the external connection portion 32 against the case surface side CF, and cannot correct the bending angle of the external connection portion 32 relative to the hole insertion portion 31. As a result, the molten resin YJ of the insulating resin member 5 enters the gap between the surface 323 of the external connection portion 32 and the mold abutment portion, and resin burrs JB extending from the outer peripheral side insulating resin portion 53 to the surface 323 side of the external connection portion 32 are likely to be generated.

[0031] As described above, the power storage device 10 of this embodiment can provide a power storage device that can avoid or reduce the occurrence of resin burrs of the insulating resin member 5 integrally formed with the current collector terminal 3 and the case cover 4 on the surface 323 side of the external connection portion 32 of the current collector terminal 3.

[0032] <Method for manufacturing the present electric storage device>

[0033] Next, a method for manufacturing the electric storage device 10 according to the embodiment of the above-disclosed technology will be described in detail with reference to the drawings. Figure 5 express Figure 1 sectional view of a molding die used in the method for manufacturing an electric storage device shown.

[0034] like Figure 5 As shown, the manufacturing method of the present power storage device 10 uses a molding die 6 having a fixed mold 61 and a movable mold 62, wherein the fixed mold 61 and the movable mold 62 respectively have mold abutting portions 3T and 4T abutting against the collector terminal 3 and the case cover 4, and a cavity portion 63 filled with molten resin YJ of the insulating resin member 5. The molding die 6 is connected to an injection molding machine (not shown) that supplies molten resin to the cavity portion 63 corresponding to the resin injection portion (gate portion) 54. The fixed mold 61 has a mold abutting portion 611 (one of the mold abutting portions 3T) abutting against the surface 323 of the external connection portion 32. The fixed mold 61 and the movable mold 62 are separated with the surface of the case cover 4 as the boundary. In addition, the movable mold 62 has a first pressing portion 64 that presses the external connection portion 32 toward the case surface side CF. The pressing portion 64 is formed in a prism shape and includes a front end portion 641 that abuts against the back surface 321 of the external connection portion 32 and a side wall portion 642 that is in contact with the outer edge portion 521 of the hollow portion 52. In addition, the pressing portion 64 can also wait at a position abutting against the back surface 321 of the external connection portion 32 when the collector terminal 3 is set in the movable mold 62, and advance toward the case surface side CF when the insulating resin member 5 is demolded after molding to play the function of an ejector.

[0035] Here, the pressing portion 64 is connected to the base end portion 643 located on the back side CB of the case by a first driving mechanism 644, and is formed to be movable in the front-back direction of the case, but may also be fixed to the movable mold 62. In addition, in order to improve the demolding property of the insulating resin member 5, the pressing portion 64 is preferably formed in a tapered shape in such a way that the front end portion 641 is slightly narrower than the base end portion 643. In addition, the movable mold 62 includes a second pressing portion 65, which abuts against the outer side surface 331 of the bent portion 33 extending from the hole insertion portion 31 of the collector terminal 3 to the back side CB of the case, and presses the bent portion 33 against the mold abutment portion 3T of the movable mold 62. The second pressing portion 65 is connected to the second driving mechanism 651, and moves forward after the collector terminal 3 is set in the movable mold 62, and retreats to a position that does not interfere with the bent portion 33 when the insulating resin member 5 is demolded after molding.

[0036] In addition, the pressing portion 64 presses the back surface 321 of the external connection portion 32 toward the shell surface side CF on the inner circumference side of the roughened surface 324 (sealing portion SR) during the period when the molten resin YJ of the insulating resin member 5 is filled into the molding die 6 (i.e., presses toward the fixed die 61 arranged on the shell surface side CF). As a result, the bending angle of the external connection portion 32 relative to the hole insertion portion 31 can be corrected, so that the gap between the surface 323 of the external connection portion 32 and the die abutment portion 611 (3T) is zero or minimized. As a result, the molten resin YJ of the insulating resin member 5 cannot enter the gap between the surface 323 of the external connection portion 32 and the die abutment portion 611 (3T), and the generation of resin burrs JB extending from the outer circumferential insulating resin portion 53 to the surface 323 side of the external connection portion 32 can be avoided or reduced.

[0037] <Modification>

[0038] The above detailed description of the present embodiment is only for illustration and does not limit the disclosed technology. Therefore, the disclosed technology can be variously improved and modified within the scope of its purpose. Figure 3 In the illustrated power storage device 10 , the surface 323 of the external connection portion 32 on the case surface side CF and the surface 531 of the outer peripheral insulating resin portion 53 on the case surface side CF are connected on the same plane.

[0039] For example, Figure 6 As shown, the following storage device 10B may be provided: the surface 323 of the external connection part 32 and the surface 531 of the peripheral insulating resin part 53 are formed on the same plane, and a groove part HM is formed on the boundary line KS between the external connection part 32 and the peripheral insulating resin part 53. By forming the groove part HM (for example, a V-shaped groove) on the boundary line KS between the external connection part 32 and the peripheral insulating resin part 53, the molten resin YJ of the insulating resin component 5 is blocked by the convex mold abutting part abutting against the groove part HM, and it is more difficult to enter the gap between the surface 323 of the external connection part 32 and the mold abutting part 611 (3T). Therefore, the generation of resin burrs JB extending from the peripheral insulating resin part 53 to the surface 323 side of the external connection part 32 can be further avoided or reduced. In addition, the groove part HM is formed on the boundary line KS between the external connection part 32 and the peripheral insulating resin part 53. Figure 6 The groove HM is formed in a V shape, but may be an arc shape or a U shape. By forming the groove HM, the creepage distance between the collector terminal 3 and the case cover 4 in the insulating resin member 5 is increased, and the insulation performance can be further improved.

[0040] Description of Reference Numerals

[0041] 3 collector terminal, 3T mold abutment portion, 4 case cover, 4T mold abutment portion, 5 insulating resin member, 6 molding die, 10, 10B storage device, 31 hole insertion portion, 32 external connection portion, 41 terminal insertion hole, 51 back side insulating resin portion, 52 hollow portion, 53 peripheral side insulating resin portion, 61 fixed mold, 62 movable mold, 63 cavity portion, 64 pressing portion, 321 back side, 322 peripheral edge, 323 surface, 324 roughened surface, 411 hole outer edge portion, 412 hole surrounding portion, 511 back side, 521 outer edge portion, 531 surface, HM groove portion, KS boundary line, SR sealing portion, YJ molten resin.

Claims

1. An electric storage device, wherein: The power storage device comprises: a housing member having a terminal insertion hole; A collector terminal having a hole insertion portion and an external connection portion, wherein the hole insertion portion is inserted into the terminal insertion hole along the front-back direction of the case, and the external connection portion is arranged on the surface side of the case member and is formed by bending relative to the hole insertion portion; and an insulating resin member formed integrally with the collector terminal and the case member in such a manner that the hole insertion portion and the external connection portion are connected to the hole outer edge portion and the hole periphery portion of the terminal insertion hole, The insulating resin member comprises: an outer peripheral insulating resin portion surrounding the outer peripheral edge of the external connecting portion over the entire circumference; and a back side insulating resin portion connecting the back side of the external connection portion, the hole outer edge portion, the hole surrounding portion, and the hole insertion portion, The back side insulating resin portion has a hollow portion formed therein, which extends from the back side of the back side insulating resin portion along the front-back direction of the housing to the back side of the external connecting portion. A ring-shaped sealing portion is formed on the back surface of the external connecting portion along the outer edge of the hollow portion.

2. The power storage device according to claim 1, wherein The surface of the external connection portion and the surface of the outer peripheral insulating resin portion are formed on the same plane, A groove portion is formed on a boundary line between the external connection portion and the outer peripheral side insulating resin portion.

3. A method for manufacturing an electric storage device, the method for manufacturing an electric storage device being the method for manufacturing an electric storage device according to claim 1 or claim 2, wherein: A molding die including a fixed die and a movable die is used, wherein the fixed die and the movable die each have a die contact portion that contacts the collector terminal and the case member and a cavity portion that is filled with molten resin of the insulating resin member, The movable mold includes a pressing portion for pressing the external connection portion toward the housing surface side. The method for manufacturing the power storage device comprises the following steps: a step of arranging the collector terminal and the case member in the molding die so as to abut against the mold abutment portion; and A step of filling the cavity portion with the molten resin while the back surface of the external connection portion is pressed toward the housing surface side by the pressing portion on the inner peripheral side of the sealing portion.

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