JP2016015229A - Current cutoff device and power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for suppressing the deformation of an electric conduction plate.SOLUTION: When pressure inside a case 11 exceeds a predetermined value, a current cutoff device 10 cuts off an electric conduction path for connecting an electrode assembly 12 housed in the case 11 to a negative electrode terminal 132 fitted to the case 11. The current cutoff device 10 comprises: an electric conduction plate 20 electrically connected to the electrode assembly 12; and a first deformation plate 40 electrically connected to the negative electrode terminal 132 and fitted to a center portion 22 of the electric conduction plate 20. The electric conduction plate 20 is provided with groove 23 so that the groove 23 surrounds the center portion 22. The groove 23 comprises: an inner-side face 231 located on the center side of the electric conduction plate 20; and an outer-side face 232 which faces the inner-side face 231 and is located on the outer peripheral side of the electric conduction plate 20. The angle between the outer-side face 232 of the groove 23 and the depth direction of the groove 23 is greater than that between the inner-side face 231 of the groove 23 and the depth direction of the groove 23.

Description

  The technology disclosed in this specification relates to a current interrupt device and a power storage device.

  Development of a current interrupting device that interrupts the current flowing through the power storage device when the power storage device is overcharged or when a short circuit occurs inside is underway. The current interrupt device is disposed between the electrode assembly and the terminal. Patent Document 1 discloses a current interrupt device. The current interrupt device of Patent Document 1 includes a deformable plate and a current plate. An energizing plate is welded to the central portion of the deformable plate. A groove is formed in the energizing plate around the welded portion. The deformation plate is deformed when the pressure in the outer can increases. When the deforming plate is deformed, the energizing plate is broken at the groove portion. When the current plate breaks, the current is cut off.

JP 2014-017051 A

  In the current interrupting device, it is required that the deforming plate and the energizing plate are firmly fixed so that the energizing plate is surely broken when the deforming plate is deformed. In order to firmly fix the current-carrying plate and the deformation plate, it is required that the current-carrying plate is not deformed as much as possible at the welding site where the current-carrying plate and the deformation plate are fixed. Then, this specification aims at providing the technique which can suppress a deformation | transformation of the welding site | part of an electricity supply board.

  The current interrupting device disclosed in this specification interrupts an energization path that connects an electrode assembly housed in a case and a positive or negative terminal fixed to the case when the pressure in the case exceeds a predetermined value. To do. The current interrupting device includes an energizing plate that is electrically connected to the electrode assembly, and a first deformation plate that is electrically connected to the terminal and is fixed to the central portion of the energizing plate. The energizing plate is formed with a groove so as to surround the central portion. The groove portion includes an inner surface located on the center side of the energizing plate and an outer surface located on the outer peripheral side of the energizing plate so as to face the inner surface. The angle formed between the outer surface of the groove and the depth direction of the groove is larger than the angle formed between the inner surface of the groove and the depth direction of the groove. The first deformation plate may be fixed to the energization plate by welding.

  According to such a configuration, since the angle formed by the outer side surface and the inner side surface with respect to the depth direction of the groove portion is different, when the groove portion is formed, the material of the current-carrying plate escapes to the outside from the inside of the groove portion. Since the escape of the material to the inner side (that is, the welded part side) of the groove part can be suppressed, deformation of the fixed part of the energizing plate can be suppressed. In addition, since the material of the energization plate escapes to a wide area outside the groove, deformation of the energization plate due to the formation of the groove can be suppressed.

  In addition, a power storage device disclosed in this specification includes any one of the current interrupting devices described above.

It is sectional drawing of the electrical storage apparatus which concerns on embodiment. It is an enlarged view of the principal part II of FIG. It is an enlarged view of the principal part III of FIG. 1 in an energized state. It is an enlarged view of the principal part III of FIG. 1 in a non-energized state. It is an enlarged view of the principal part V of FIG. It is a reverse view of an electricity supply board. It is a figure explaining the method of forming a groove part. It is an enlarged view of the principal part of the electrical storage apparatus which concerns on other embodiment.

  Hereinafter, embodiments will be described with reference to the accompanying drawings. As shown in FIG. 1, the power storage device 1 includes a case 11, an electrode assembly 12 accommodated in the case 11, and terminals 13 (a positive terminal 131 and a negative terminal 132) fixed to the case 11. . The electrode assembly 12 and the terminal 13 are electrically connected. The power storage device 1 includes a current interrupt device 10 disposed between the terminal 13 and the electrode assembly 12. The power storage device 1 is mounted on, for example, an electric vehicle or a hybrid vehicle.

  The case 11 is a substantially rectangular parallelepiped box-shaped member. The case 11 is made of metal, and is made of, for example, stainless steel or aluminum. The case 11 includes a main body 111 and a lid body 112 fixed to the main body 111. The main body 111 has a bottomed rectangular tube shape having an opening. The lid body 112 covers the opening of the main body 111. Hereinafter, in the main body 111, the side on which the lid body 112 is disposed is referred to as “upper side”, and the opposite side is referred to as “lower side”. An electrolytic solution is accommodated in the main body 111. The lid body 112 of the case 11 is formed with a positive electrode opening 85 and a negative electrode opening 86. A positive electrode terminal 131 is fixed to the opening 85 for the positive electrode. The negative electrode terminal 132 is fixed to the opening 86 for the negative electrode.

The electrolytic solution is preferably a nonaqueous electrolytic solution in which a supporting salt (electrolyte) is dissolved in a nonaqueous solvent. As a non-aqueous solvent, a solvent containing a chain ester such as ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), ethyl acetate, A solvent such as methyl propionate or a mixture thereof can be used. Moreover, as a supporting salt (electrolyte), for _example, can be used LiPF _6, LiBF 4, LiAsF _6, and the like. The electrolyte contains an aromatic monomer additive.

  The electrode assembly 12 is disposed inside the case 11. An insulating member 71 is disposed between the electrode assembly 12 and the case 11. The insulating member 71 insulates the electrode assembly 12 from the case 11. The electrode assembly 12 is immersed in the electrolytic solution. When the power storage device 1 is overcharged or overdischarged, gas is generated from the electrode assembly 12 and the pressure in the case 11 increases.

  The electrode assembly 12 includes a positive electrode sheet, a negative electrode sheet, and a separator disposed between the positive electrode sheet and the negative electrode sheet. The electrode assembly 12 has a configuration in which a plurality of positive electrode sheets, a plurality of negative electrode sheets, and a plurality of separators are laminated. The positive electrode sheet and the negative electrode sheet include a current collector and an active material layer formed on the current collector. The electrode assembly 12 includes a positive current collecting tab 81 and a negative current collecting tab 82. The positive electrode current collecting tab 81 is formed on the upper end portion of the positive electrode sheet. The negative electrode current collecting tab 82 is formed on the upper end portion of the negative electrode sheet. The positive electrode current collecting tab 81 and the negative electrode current collecting tab 82 protrude upward. The positive electrode current collecting tab 81 is fixed to the positive electrode lead 83. The negative electrode current collecting tab 82 is fixed to the negative electrode lead 84.

  The positive electrode lead 83 is connected to the positive electrode current collecting tab 81 and the positive electrode terminal 131. The positive electrode current collecting tab 81 and the positive electrode terminal 131 are electrically connected via the positive electrode lead 83. An insulating member 72 is disposed between the positive electrode lead 83 and the case 11. The insulating member 72 insulates the positive electrode lead 83 from the case 11.

  The negative electrode lead 84 is connected to the negative electrode current collecting tab 82 and the connection member 87. The connecting member 87 is electrically connected to the negative terminal 132 via the current interrupt device 10. Therefore, the negative electrode current collecting tab 82 and the negative electrode terminal 132 are electrically connected via the negative electrode lead 84, the connection member 87, and the current interrupt device 10. Thereby, an energization path for connecting the electrode assembly 12 and the negative electrode terminal 132 is formed. The current interrupt device 10 can interrupt this energization path. The configuration of the current interrupt device 10 will be described later. An insulating member 73 is disposed between the negative electrode lead 84 and the case 11. The insulating member 73 insulates the negative electrode lead 84 from the case 11.

  The terminals 13 (the positive terminal 131 and the negative terminal 132) are fixed to the lid body 112 of the case 11. The positive terminal 131 and the negative terminal 132 protrude outside the case 11. The positive electrode terminal 131 and the negative electrode terminal 132 are arranged with a space therebetween. The positive terminal 131 and the negative terminal 132 are electrically connected to the electrode assembly 12.

  As shown in FIG. 2, the positive terminal 131 is caulked and fixed to the lid 112 of the case 11. The positive terminal 131 includes a cylindrical portion 91, a base portion 92, and a fixing portion 93. The cylindrical portion 91 is inserted into the positive electrode opening 85. The base 92 is formed in an annular shape. The base portion 92 is fixed to the lower end portion of the cylindrical portion 91. The base 92 is disposed inside the case 11. The fixing portion 93 is formed in an annular shape. The fixed portion 93 is fixed to the upper end portion of the cylindrical portion 91. The fixing portion 93 is disposed outside the case 11. The positive terminal 131 is fixed to the case 11 by pressing the fixing portion 93 and the base portion 92 up and down.

  The positive terminal 131 is in contact with the positive external terminal 301. The positive external terminal 301 is connected to an external circuit (not shown). An insulating member 74 is disposed between the positive electrode side external terminal 301 and the case 11. The insulating member 74 insulates the positive external terminal 301 from the case 11. An insulating member 75 is disposed between the positive terminal 131 and the case 11. The insulating member 75 insulates the positive terminal 131 and the case 11.

  As shown in FIG. 3, the negative terminal 132 is caulked and fixed to the case 11. The negative terminal 132 includes a cylindrical portion 94, a base portion 95, and a fixing portion 96. The cylindrical portion 94 is inserted into the opening 86 for the negative electrode. A through hole 97 is formed in the cylindrical portion 94. The base portion 95 is formed in an annular shape. The base portion 95 is fixed to the lower end portion of the cylindrical portion 94. The base portion 95 is disposed inside the case 11. A concave portion 98 is formed in the base portion 95. The recess 98 communicates with the through hole 97. The fixing part 96 is formed in an annular shape. The fixed portion 96 is fixed to the upper end portion of the cylindrical portion 94. The fixing portion 96 is disposed outside the case 11. The negative terminal 132 is fixed to the case 11 by pressing the fixing portion 96 and the base portion 95 up and down.

  The negative terminal 132 is in contact with the negative external terminal 302. The negative external terminal 302 is connected to an external circuit (not shown). An insulating member 76 is disposed between the negative electrode side external terminal 302 and the case 11. The insulating member 76 insulates the negative external terminal 302 from the case 11. An insulating member 77 is disposed between the negative terminal 132 and the case 11. The insulating member 77 insulates the negative electrode terminal 132 from the case 11.

  Next, the configuration of the current interrupt device will be described. As shown in FIGS. 3 and 4, the current interrupt device 10 includes an energization plate 20, a first deformation plate 40, and a second deformation plate 30. The current interrupt device 10 is disposed inside the case 11. The current interrupt device 10 is disposed below the negative terminal 132. FIG. 3 shows an energized state, and FIG. 4 shows a non-energized state.

  The energization plate 20 is a metal member and has conductivity. The energization plate 20 is connected to the connection member 87. The energization plate 20 is electrically connected to the electrode assembly 12 via the connection member 87 and the negative electrode lead 84.

  The energization plate 20 is disposed between the first deformation plate 40 and the second deformation plate 30. The energization plate 20 is disposed below the first deformation plate 40 and is disposed above the second deformation plate 30. A space 54 is formed between the energization plate 20 and the second deformation plate 30. The energization plate 20 is fixed to the first deformation plate 40 and the second deformation plate 30. The central portion 22 of the energization plate 20 is fixed to the first deformation plate 40, and the outer peripheral portion 21 of the energization plate 20 is fixed to the second deformation plate 30. The energization plate 20 has a front surface 28 and a back surface 29. Here, the surface 28 of the energization plate 20 is a surface facing the first deformation plate 40. Further, the back surface 29 of the energization plate 20 is a surface facing the second deformation plate 30.

  A groove portion 23 is formed on the back surface 29 of the energization plate 20 so as to surround the central portion 22. As shown in FIG. 5, the groove 23 includes an inner surface 231, an outer surface 232, and a bottom surface 233. The inner surface 231 of the groove 23 is formed on the center side of the energizing plate 20. The outer surface 232 of the groove 23 is formed on the outer peripheral side of the energizing plate 20. The inner side surface 231 and the outer side surface 232 are formed at positions facing each other. The inner surface 231 and the outer surface 232 of the groove 23 are inclined with respect to the depth direction of the groove 23. Further, the inner side surface 231 and the outer side surface 232 of the groove portion 23 are inclined with respect to the bottom surface 233 of the groove portion 23. The angle θ1 formed by the outer surface 232 of the groove 23 and the depth direction of the groove 23 is larger than the angle θ2 formed by the inner surface 231 of the groove 23 and the depth direction of the groove 23. An angle θ1 ′ formed between the outer surface 232 and the bottom surface 233 of the groove 23 is smaller than an angle θ2 ′ formed between the inner surface 231 and the bottom surface 233 of the groove 23.

  FIG. 6 is a rear view of the energization plate. As shown in FIG. 6, the energization plate 20 is formed in a circular shape. The groove 23 is formed to extend in a circular shape on the back surface 29 of the energization plate 20. When the current-carrying plate 20 is viewed in plan, the groove 23 is formed in a continuous annular shape without being interrupted in the circumferential direction. The groove part 23 is formed inside the outer peripheral part 21. The groove portion 23 is formed outside the central portion 22. The groove part 23 is formed around the central part 22. The groove portion 23 is weaker than other portions of the current-carrying plate 20 and easily breaks. The energization plate 20 is broken starting from the groove 23. Thereby, electricity supply is interrupted | blocked. As shown in FIG. 3, the energizing plate 20 is not broken when energized, and becomes non-energized when broken as shown in FIG. 4.

  Moreover, the groove part 23 is formed by press work. When forming the groove portion 23, as shown in FIG. 7, the back surface 29 of the current-carrying plate 20 is pressed by a mold 200 having a projection portion 202. The groove 23 is formed in the portion pressed by the protrusion 202. When manufacturing the electric current interruption apparatus 10, the electricity supply board 20 in which the groove part 23 was formed by the projection part 202 shown in FIG. The protrusion 202 includes an inner surface 2021, an outer surface 2022, and a top surface 2023. An inner side surface 2021 of the protrusion 202 is formed on the center side of the mold 200. The outer surface 2022 of the protrusion 202 is formed on the outer peripheral side of the mold 200. The inner side surface 2021 and the outer side surface 2022 are formed at positions facing each other. The inner side surface 2021 and the outer side surface 2022 of the protruding portion 202 are inclined with respect to the protruding direction of the protruding portion 202. Further, the inner side surface 2021 and the outer side surface 2022 of the protrusion 202 are inclined with respect to the top surface 2023 of the protrusion 202. An angle θ1 formed between the outer surface 2022 of the protruding portion 202 and the protruding direction of the protruding portion 202 is larger than an angle θ2 formed between the inner side surface 2021 of the protruding portion 202 and the protruding direction of the protruding portion 202. An angle θ1 ′ formed between the outer surface 2022 of the protrusion 202 and the top surface 2023 is smaller than an angle θ2 ′ formed between the inner surface 2021 of the protrusion 202 and the top surface 2023.

  In addition, a through hole 50 is formed in the energizing plate 20. The through hole 50 penetrates the energizing plate 20. The through hole 50 communicates with the space 54. The through hole 50 is formed between the outer peripheral portion 21 and the central portion 22 of the energizing plate 20. The through hole 50 is formed outside the groove 23.

  The first deformation plate 40 is a metal diaphragm. The first deformation plate 40 has conductivity and is formed in a circular shape in plan view. The first deformation plate 40 is disposed above the energization plate 20. The first deformation plate 40 has a central portion 42 and an outer peripheral portion 41. As shown in FIG. 3, the first deformable plate 40 is convex downward when energized, and is convex upward when not energized as shown in FIG. When energized, the central portion 42 of the first deformable plate 40 protrudes downward.

  The central portion 42 of the first deformation plate 40 is fixed to the central portion 22 of the energization plate 20. The central portion 42 of the first deformable plate 40 and the central portion 22 of the energizing plate 20 are fixed by welding. The lower surface of the first deformation plate 40 is fixed to the upper surface of the energization plate 20. An insulating member 78 is disposed between the outer peripheral portion 41 of the first deformation plate 40 and the outer peripheral portion 21 of the energizing plate 20. The insulating member 78 insulates the first deformable plate 40 and the energizing plate 20.

  The first deformation plate 40 is disposed below the negative electrode terminal 132. The outer peripheral portion 41 of the first deformation plate 40 is fixed to the base portion 95 of the negative electrode terminal 132. The outer peripheral portion 41 of the first deformation plate 40 and the base portion 95 of the negative electrode terminal 132 are fixed by welding. The upper surface of the first deformation plate 40 is fixed to the lower surface of the negative electrode terminal 132.

  The second deformation plate 30 is a metal diaphragm. The second deformation plate 30 has conductivity and is formed in a circular shape in plan view. The second deformation plate 30 is disposed below the energization plate 20. The second deformation plate 30 has a central portion 32 and an outer peripheral portion 31. As shown in FIG. 3, the second deformable plate 30 is convex downward when energized, and is convex upward when not energized as shown in FIG. When energized, the central portion 32 of the second deformable plate 30 protrudes downward. When the pressure in the case 11 exceeds a predetermined value, the second deformation plate 30 is deformed from a downward convex state to an upward convex state. That is, the second deformable plate 30 is inverted upward from the downwardly convex state. When in a non-energized state, the central portion 32 of the second deformation plate 30 protrudes upward.

  The second deformation plate 30 is provided with a protrusion 35. The protrusion 35 is provided in the central portion 32 of the second deformation plate 30. The protrusion 35 is fixed to the upper surface of the second deformation plate 30. The protrusion 35 protrudes upward. The protrusion 35 is disposed below the central portion 22 of the energization plate 20. The protrusion 35 protrudes toward the central portion 22 of the energization plate 20. The protrusion 35 collides with the central portion 22 of the energizing plate 20 when the second deformable plate 30 is deformed upward. The protrusion 35 is formed of an insulator. In another example, an insulating member may be disposed between the protrusion 35 and the energizing plate 20.

  The outer peripheral portion 31 of the second deformable plate 30 is fixed to the outer peripheral portion 21 of the energizing plate 20. The outer peripheral part 31 of the 2nd deformation board 30 and the outer peripheral part 21 of the electricity supply board 20 are being fixed by welding. The upper surface of the second deformation plate 30 is fixed to the lower surface of the energization plate 20. The outer peripheral part 31 of the 2nd deformation board 30 and the outer peripheral part 21 of the electricity supply board 20 may be fixed in the insulated state.

  The energization plate 20, the first deformation plate 40, and the second deformation plate 30 are fixed by a fixing member 70. The fixing member 70 caulks and fixes the energization plate 20, the first deformation plate 40, and the second deformation plate 30. The fixing member 70 fixes the energization plate 20, the first deformation plate 40, and the second deformation plate 30 to the base portion 95 of the negative electrode terminal 132. An insulating member 79 is disposed inside the fixing member 70. The insulating member 79 insulates the energization plate 20, the first deformation plate 40, the second deformation plate 30, and the negative electrode terminal 132 from the fixing member 70.

  In the current interrupt device 10 and the power storage device 1 having the above-described configuration, the angle θ1 formed between the outer surface 232 of the groove 23 and the depth direction of the groove 23 is the depth direction of the inner surface 231 of the groove 23 and the groove 23. It is made to be larger than the angle θ2 formed by In this case, when the groove portion 23 is formed, the material of the current-carrying plate 20 escapes to the outside rather than the inside of the groove portion 23 as indicated by an arrow in FIG. As a result, since the material of the energization plate 20 escapes to a wide area, deformation of the energization plate 20 due to the formation of the groove portion 23 can be suppressed. In particular, since the material of the current-carrying plate 20 escapes to the outside rather than the inside of the groove portion 23, the deformation of the central portion 22 inside the groove portion 23 can be suppressed. Thereby, when welding the 1st deformation board 40 to the center part 22 of the electricity supply board 20, it can weld favorably. Further, the gap between the central portion 22 of the energization plate 20 and the protrusion 35 can be accurately ensured. Thereby, the electric current interruption apparatus 10 operate | moves correctly.

  As mentioned above, although one embodiment was described, a specific mode is not limited to the above-mentioned embodiment. For example, in the said embodiment, although it was the structure provided with the 2nd deformation plate 30, it is not limited to this structure, As shown in FIG. Good. In FIG. 8, the same components as those in FIG. 3 are denoted by the same reference numerals and description thereof is omitted.

  Moreover, in the said embodiment, although the electric current interruption apparatus 10 was arrange | positioned between the electrode assembly 12 and the negative electrode terminal 132, it is not limited to this structure. In other embodiments, the current interrupt device 10 may be disposed between the electrode assembly 12 and the positive terminal 131. In this case, the current interrupting device 10 interrupts the energization path connecting the electrode assembly 12 and the positive terminal 131.

  Moreover, in the said embodiment, although the groove part 23 was formed in the cyclic | annular form continuous without interrupting in the circumferential direction, it is not limited to this structure. In other embodiments, the groove 23 is formed discontinuously in the circumferential direction and may be interrupted. That is, the groove part 23 may be formed so as to extend in a circular shape while being interrupted in the circumferential direction. Moreover, in the said embodiment, although the groove part 23 was formed in the back surface 29 of the electricity supply board 20, it is not limited to this structure. In other embodiments, the groove 23 may be formed on the surface 28 of the energization plate 20.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

DESCRIPTION OF SYMBOLS 1; Power storage device 10; Current interruption device 11; Case 12; Electrode assembly 13; Terminal 20; Current supply plate 21; Outer peripheral part 22; Part 32; central part 35; projection 40; first deformation plate 41; outer peripheral part 42; central part 50; through hole 54; space 70; fixing member 71; insulating member 72; insulating member 73; Insulating member 76; Insulating member 77; Insulating member 78; Insulating member 79; Insulating member 81; Positive electrode current collecting tab 82; Negative electrode current collecting tab 83; Positive electrode lead 84; Negative electrode lead 85; (For negative electrode) opening 87; connection member 91; columnar part 92; base part 93; fixing part 94; cylindrical part 95; base part 96; fixing part 97; through hole 98; ; Positive terminal 132; Negative terminal 00; mold 202; protrusion 231; an inner surface 232; an outer surface 233; bottom 301; positive side external terminal 302; negative electrode side external terminal

Claims (3)

A current interrupting device for interrupting an energization path connecting an electrode assembly housed in a case and a positive or negative terminal fixed to the case when a pressure in the case exceeds a predetermined value;
An energization plate electrically connected to the electrode assembly;
A first deformation plate electrically connected to the terminal and fixed to a central portion of the energization plate,
The energizing plate is formed with a groove so as to surround the central portion,
The groove includes an inner surface located on the center side of the energization plate, and an outer surface located on the outer peripheral side of the energization plate facing the inner surface,
The current interrupting device, wherein an angle formed between the outer surface of the groove and a depth direction of the groove is larger than an angle formed between the inner surface of the groove and the depth direction of the groove.   The current interrupt device according to claim 1, wherein the first deformation plate is fixed to the energization plate by welding. A power storage device comprising the current interrupt device according to claim 1.

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