JP6198130B2 - Electricity storage element - Google Patents

Description

  The present invention relates to a chargeable / dischargeable power storage element.

  Conventionally, a chargeable / dischargeable power storage element such as a secondary battery is known. As shown in FIGS. 9 and 10, this power storage element includes an electrode body 102, a case 104 that houses the electrode body 102 together with an electrolytic solution, an external terminal 106 that is attached to the case 104, and an electrode body 102 and an external terminal 106. And a current collector 108 that is connected in a conductive manner (Patent Document 1). The case 104 has a bottomed cylindrical case main body 104A having an opening, a lid 104B that closes the opening and constructs an internal space s in which the electrode body 102 and the electrolytic solution are accommodated together with the case main body 104A, Have

  In this storage element 100, when overcharging or overvoltage occurs due to charging or the like, and the supply of current to the electrode body 105 continues in that state, the gas pressure in the case (inside of the case 20) is generated by the gas generated from the electrolyte. Pressure) rises too much.

JP2013-149387A

  In view of the above problems, an object of the present invention is to provide a power storage element that can stop supply of current to an electrode body or suppress supply of current when overcharge or overvoltage occurs.

The electricity storage device according to the present invention is:
An electrode body;
A case for housing the electrode body;
An external terminal attached to the case;
A current collector that connects the electrode body and the external terminal in a conductive manner;
A pressure receiving portion to which the gas pressure in the case is applied;
A region on the opposite side of the pressure receiving portion across the current collector, adjacent to an intermediate portion between the first portion connected to the external terminal and the second portion connected to the electrode body in the current collector A hook portion to be disposed on,
A box-shaped support part that has a box shape having an opening and supports the pressure receiving part;
The pressure receiving portion is a plate-like deformation portion having a plate shape that closes the opening of the box-shaped support portion, and the hook-like deformation portion is connected to a surface opposite to the box-shaped support portion. Have
The plate-like deforming portion is deformed so as to bulge toward the inside of the box-shaped support portion due to the increase in the gas pressure .

According to such a configuration, when gas is generated from the electrolyte due to overcharging at the time of charging, etc., and the gas pressure in the case rises, the hooking part tears the intermediate part to divide the current collector, or The hook portion can stretch the intermediate portion and increase the electrical resistance of a part of the current collector (stretched portion). As a result, the energization path leading from the external terminal to the electrode body is divided (that is, the first part and the second part are divided in the current collector), and the supply of current from the external terminal to the electrode body is stopped. Alternatively, the energization state of the energization path is greatly reduced, and thereby the supply of current from the external terminal to the electrode body is greatly suppressed.
Specifically, when the gas pressure in the case increases during charging, the pressure in the space surrounded by the box-shaped support portion and the plate-shaped deformation portion (hereinafter also referred to as “enclosed space”); A pressure difference with another space (a space in which the electrode body is accommodated) in the case is formed, and the plate-shaped deformed portion is deformed so as to bulge toward the inside of the box-shaped support portion. As a result, the hooking portion is pulled toward the inside of the box-shaped support portion by the plate-like deforming portion, the intermediate portion is torn off by the hooking portion, and as a result, the current collector is divided.

in this case,
The width dimension of the intermediate part is preferably smaller than the width dimension of parts adjacent to both sides of the intermediate part across the intermediate part.

  In this way, by making the width dimension of the intermediate part smaller than the width dimension of the parts adjacent to both sides thereof, the hook part moves and the force that pulls the intermediate part toward the pressure receiving part can be concentrated on the intermediate part. it can. Thereby, a hook part can tear an intermediate part more reliably.

Further, in the power storage element,
It is preferable that the hook portion is connected to a position corresponding to the center of the opening of the box-shaped support portion on the surface opposite to the plate-shaped deformable portion.

  By connecting the dividing portion at such a position, the force by which the dividing portion pulls the intermediate portion when the plate-like deforming portion is deformed so as to bulge toward the inside of the box-shaped indicating portion due to the pressure difference. Become the largest. For this reason, a collector can be more reliably divided.

In addition, the power storage element is
You may further provide the communication part which connects the exterior of a case and the space enclosed by the box-shaped support part and the plate-shaped deformation part.

  According to such a configuration, the pressure in the enclosed space can be maintained at the external pressure (that is, substantially constant) regardless of the temperature in the case and the like, and thereby the current collector is divided. The gas pressure value at the time can be made constant. That is, the internal pressure of the enclosed space varies depending on the ambient temperature around the box-shaped support and the plate-like deformed portion, and the variation prevents the gas pressure value from varying when the current collector is divided. be able to.

Moreover, as another aspect of the electricity storage device according to the present invention,
The plate-shaped deformable portion and the hook portion may be made of resin.

  In this way, the plate-like deformed portion and the hooking portion that divide the current collector are made of resin, so that in the current collector after the division, the first portion and the second portion are the plate-like deformed portion and It is possible to reliably prevent conduction through the hook portion.

Moreover, as another aspect of the electricity storage device according to the present invention,
The case has a gas discharge valve that discharges the gas in the case to the outside when the gas pressure becomes the first value or more,
The intermediate portion may be torn off by the hook portion when the gas pressure in the case is a second value higher than the normal pressure and smaller than the first value.

  According to such a configuration, the current collector is divided before the gas in the case rises to the gas pressure (gas pressure value) discharged to the outside from the gas discharge valve, and current supply from the outside to the electrode body is stopped. Stop. Thereby, before a gas exhaust valve opens (actuates), generation | occurrence | production of the gas by supplying an electric current to an electrode body can be suppressed, and it can suppress that a gas pressure raises. Moreover, even if the gas pressure continues to rise after the supply of current to the electrode body is stopped, the gas discharge valve discharges the gas to the outside when the gas pressure rises to the first value. Rupture can be prevented more reliably.

Moreover, the electricity storage device according to the present invention is:
An electrode body;
A case for housing the electrode body;
An external terminal attached to the case;
A current collector that connects the electrode body and the external terminal in a conductive manner;
A pressure receiving portion to which the gas pressure in the case is applied;
A hook portion disposed on the opposite side of the pressure receiving portion with the current collector interposed therebetween, and moves to the pressure receiving portion side when a predetermined gas pressure is applied to the pressure receiving portion. And a hook portion that tears or stretches an intermediate portion between the first portion connected to the external terminal and the second portion connected to the electrode body.

  According to such a configuration, when a predetermined gas pressure is applied to the pressure receiving portion due to gas being generated from the electrolyte due to overcharging at the time of charging or the like due to overvoltage, and the gas pressure in the case is applied to the pressure receiving portion, The intermediate part is torn by moving to the current collector and the current collector is divided, or the hooking part extends the intermediate part to increase the electrical resistance of a part of the current collector. As a result, the energization path leading from the external terminal to the electrode body is divided, and the supply of current from the external terminal to the electrode body is stopped, or the energization state of the energization path is greatly reduced, thereby The supply of current to the electrode body is greatly suppressed.

  As described above, according to the present invention, it is possible to provide a power storage element that can stop the supply of current to the electrode body or suppress the supply of current when overcharge or overvoltage occurs.

It is a perspective view of the nonelectrolyte secondary battery concerning this embodiment. It is a front view of the non-electrolyte secondary battery. It is a III-III position sectional view in Drawing 1. It is an expanded sectional perspective view of a terminal part periphery. It is a disassembled perspective view around the terminal part. It is an expanded sectional view of the VI-VI position in FIG. It is a partial expanded sectional view around the said terminal for demonstrating the operation | movement which a pressure-sensitive deformation | transformation part divides | segments a collector, Comprising: It is a partial expanded sectional view before the gas pressure in a case rises. It is a partial expanded sectional view around the said terminal for demonstrating the operation | movement which a pressure-sensitive deformation | transformation part divides | segments a collector, Comprising: It is the partial expanded sectional view after the gas pressure in a case rose. It is a perspective view of the conventional electrical storage element. It is a longitudinal cross-sectional view of the said electrical storage element.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The electricity storage device according to the present embodiment is a non-electrolyte secondary battery (hereinafter simply referred to as “battery”) such as a lithium ion secondary battery. In the following, the X-axis direction shown in FIGS. 1 to 3 is defined as the battery width direction, the Y-axis direction is defined as the battery front-rear direction, and the Z-axis direction is defined as the battery height direction.

  As shown in FIGS. 1 to 3, the battery 10 includes a case 20, an electrode body 12, a pair of terminal portions 30 </ b> A and 30 </ b> B, and a pair of current collectors 14 </ b> A and 14 </ b> B.

  The case 20 includes a case main body 22 and a lid body 24. The case 20 accommodates the electrode body 12, the pair of current collectors 14 </ b> A and 14 </ b> B, the electrolytic solution, and the like in an internal space S surrounded by the case main body 22 and the lid body 24. The case main body 22 and the lid body 24 are formed of an aluminum-based metal material such as aluminum or an aluminum alloy, for example. The case 20 is configured by welding the ends of the case body 22 and the lid body 24 to each other.

  The case body 22 has a bottomed rectangular tube shape that is flat in the width direction. Specifically, the case main body 22 includes a bottom wall portion 220 and a rectangular tubular peripheral wall 222 that is erected from the periphery of the bottom wall portion 220 in the normal direction (Z-axis direction) of the bottom wall portion 220. . The bottom wall 220 has a rectangular shape that is long in the width direction and has four corners in a circular arc in a plan view.

  The lid body 24 is overlapped with the peripheral edge of the opening of the case body 22 to close the opening of the case body 22. The lid body 24 has a shape corresponding to the outer peripheral edge (contour) of the case body 22 in plan view. That is, the lid body 24 is a rectangular plate material that is long in the width direction and has four arcs in a plan view.

  The lid body 24 is provided with a pair of terminal through holes 240, 240, a gas exhaust valve 242, and an injection part 244 (see FIG. 3). The pair of terminal through holes 240 and 240 are provided in the lid body 24 with a gap in the width direction (X-axis direction). The gas discharge valve 242 has a thin portion and a fracture groove, and is provided at the center of the lid body 24. The gas discharge valve 242 opens when the gas pressure in the case 20 (internal pressure in the case 20) becomes larger than a predetermined value (first value) (specifically, the thin portion is torn from the fracture groove). As a result, the inside of the case 20 is communicated with the outside, and the gas in the case 20 is discharged. Thereby, the gas discharge valve 242 reduces the internal pressure of the raised case 20. The injection part 244 has a liquid injection hole 245 provided in the lid 24 and a plug 246 that closes the liquid injection hole 245. The liquid injection hole 245 is an opening for injecting the electrolytic solution into the case 20, and the plug 246 closes the liquid injection hole 245 by being inserted into the liquid injection hole 245 after the liquid injection.

  The electrode body 12 includes a strip-shaped positive electrode sheet 120, a strip-shaped negative electrode sheet 122, and a strip-shaped separator 124. The positive electrode sheet 120 and the negative electrode sheet 122 are wound into a long cylindrical shape with the separator 124 interposed therebetween and shifted from each other in the width direction (direction perpendicular to the longitudinal direction of the belt-like sheet). 12 is configured (see FIG. 3).

  The positive electrode sheet 120 is obtained by, for example, supporting a positive electrode active material on the surface of a strip-shaped aluminum foil. The negative electrode sheet 122 is, for example, a negative electrode active material supported on the surface of a strip-shaped copper foil. The positive electrode sheet 120 and the negative electrode sheet 122 have an uncoated portion of the active material at the edge in the width direction. Thereby, the aluminum foil and the copper foil in which the active material is not applied are exposed at the end in the width direction of the electrode body 12. As described above, the electrode body 12 has a protruding portion (positive electrode of the electrode body) 126 on the positive electrode side formed by protruding only the positive electrode sheet 120 (a portion where the positive electrode active material is not coated) at one end portion in the width direction. And a negative electrode-side protruding portion (a negative electrode of the electrode body) 126 configured by protruding only the negative electrode sheet 122 (a portion where the negative electrode active material is not coated) at the other end in the width direction.

  The electrode body 12 configured as described above is accommodated in the case 20 in a state of being insulated from the case 20 by being entirely covered with an insulating cover (not shown).

  The current collectors 14A and 14B are arranged along the electrode body 12 in the case 20, and connect the protruding portion 126 of the electrode body 12 and the terminal portions 30A and 30B (external terminals 31A and 31B) in a conductive manner. The battery 10 of the present embodiment includes a positive electrode current collector 14A and a negative electrode current collector 14B. The positive electrode current collector 14A connects the positive electrode-side protruding portion 126 and the positive electrode terminal portion 30A in a conductive manner. The negative electrode current collector 14 </ b> B connects the negative electrode-side protruding portion 126 and the negative electrode terminal portion 30 </ b> B in a conductive manner. In the present embodiment, the positive electrode current collector 14A is made of, for example, aluminum or an aluminum alloy. Further, the negative electrode current collector 14B is made of, for example, copper or a copper alloy.

  As shown in FIGS. 4 and 5, the positive electrode current collector 14 </ b> A includes a terminal side connection portion 140 </ b> A that is directly or indirectly connected to the positive electrode terminal portion 30 </ b> A and a protruding portion of the electrode body 12. 126 and the electrode body side connection part (2nd site | part) 141 connected directly or indirectly. The positive electrode current collector 14A is formed by bending a plate-shaped metal material cut into a predetermined shape so that the terminal-side connecting portion 140A and the electrode-body-side connecting portion 141 extend along the electrode body 12 in a front view. Is formed into a bent shape (substantially L-shaped) at the boundary portion.

  140 A of terminal side connection parts connect the front-end | tip part (1st site | part) 142, the base 143 by the side of the electrode body 12 rather than the front-end | tip part 142 in the conduction | electrical_connection path (current flow direction), and the front-end | tip part 142 and the base 143. Connecting portion (intermediate portion) 144 to be connected.

  The connecting portion 144 is a portion that is torn off by the engaging portion 35 in the positive terminal portion 30A when the gas pressure in the case 20 rises to a predetermined value (second value). The width dimension (dimension in the Y-axis direction) of the connecting portion 144 is smaller than the width dimensions of the distal end portion 142 and the base portion 143 that are adjacent (positioned) on both sides of the connecting portion 144 with the connecting portion 144 interposed therebetween. The connecting portion 144 of the present embodiment has a shape that extends in the X-axis direction at the center position in the Y-axis direction of the terminal-side connecting portion 140A, and that the thickness dimension (dimension in the Z-axis direction) gradually decreases toward the center in the X-axis direction. Have The connecting portion 144 is formed by cutting out a plate-like portion having a constant dimension in the Y-axis direction at each position in the X-axis direction from both sides in the Y-axis direction. The terminal-side connecting portion 140A is arranged so that the connecting portion 144 is substantially at the center position of the terminal portion 30A in the X-axis direction. Further, when the gas pressure in the case 20 is higher than the normal pressure and is a second value smaller than the first value (the value at which the gas discharge valve 242 opens), the connecting portion 144 is engaged 35. Torn off by. In the present embodiment, the normal pressure is a gas pressure (internal pressure) in the case 20 when the battery 10 is not overcharged or overvoltage.

  The front end portion 142 extends from the connection portion 144 toward the center in the width direction of the battery 10 to a position corresponding to the end portion of the positive electrode terminal portion 30A, and has a notch 142A in which the positive electrode terminal portion 30A is locked. At the tip. Further, the base portion 143 has a through-hole 143A that extends from the connection portion 144 toward the end portion of the electrode body 12 toward the outer side in the width direction of the battery 10 and locks the positive terminal portion 30A. The through hole 143A is provided at a position corresponding to the end of the pressure detection unit 34 included in the positive electrode terminal unit 30A in the X-axis direction.

  The negative electrode current collector 14B is directly or indirectly connected to the terminal side connection part 140B connected directly or indirectly to the negative electrode terminal part 30B and the protrusion 126 of the electrode body 12. The electrode body side connection part 141 is provided. The terminal-side connecting portion 140 </ b> B in the negative electrode current collector 14 </ b> B is a plate-shaped portion having a constant width extending along the electrode body 12. That is, unlike the terminal side connection part 140A in the positive electrode current collector 14A, the connection part 144 having a smaller width than the other parts (the tip part 142 and the base part 143) is not provided.

  The battery 10 of this embodiment is provided with a terminal portion 30A for positive electrode and a terminal portion 30B for negative electrode.

  The positive terminal portion 30 </ b> A includes an external terminal 31 </ b> A, a gasket 32, an insulating member 33 </ b> A, a pressure detector 34, an engaging portion 35, and a locking member 36.

  The external terminal 31A is a part to which a conductor (not shown) such as a cable or a bus bar is connected. The external terminal 31A is attached to the case 20 in a state where the gasket 32 is insulated from the case 20 (specifically, the lid body 24). The external terminal 31A is connected to the electrode body 12 so as to be conductive.

  The external terminal 31A includes a cylindrical portion 311A extending vertically and a flange portion 312A extending from the upper end of the cylindrical portion 311A to the radially outer side of the cylindrical portion 311A. In the external terminal 31A, a through hole extending in the central axis (Z-axis) direction of the cylindrical portion 311A is formed in the central portion in plan view. An inner peripheral surface (communication portion) 313 of the cylindrical portion 311 </ b> A that defines the through hole communicates the internal space of the pressure detection portion 34 with the outside of the case 20. The cylindrical portion 311 </ b> A is inserted through a terminal through hole 240 provided in the lid body 24. The cylindrical portion 311A is also inserted through the through hole 330 of the insulating member 33A and the through hole 344 of the pressure detection unit 34. And the lower end part of cylindrical part 311A inserted to the inside of the pressure detection part 34 is crimped (refer FIG. 4). As a result, the external terminal 31A, the gasket 32, the lid 24, the insulating member 33A, and the pressure detector 34 are fixed to each other. Note that the cylindrical portion 311A shown in FIG. 5 is in a state before the lower end portion is crimped.

  The gasket 32 is an insulating member, and is disposed between the external terminal 31 </ b> A and the lid body 24 to insulate between the external terminal 31 </ b> A and the lid body 24. Further, the gasket 32 seals between the external terminal 31 </ b> A and the peripheral portion of the terminal through hole 240 of the lid body 24 so that the gas in the case 20 does not leak outside from the terminal through hole 240. In the gasket 32, a through hole 320 through which the cylindrical portion 311 </ b> A of the external terminal 31 </ b> A is inserted is provided at a position overlapping the terminal through hole 240 of the lid body 24 in the vertical direction.

  The pressure detection unit 34 includes a box-shaped support unit 340 formed of a conductive material such as metal, and a plate-shaped deformation unit (pressure receiving unit) 341 formed of an insulating material such as resin. .

  The box-shaped support part 340 has a box shape with an open lower end. Specifically, the box-shaped support 340 includes a box-shaped main body part 342 having an approximately rectangular parallelepiped appearance and an open lower end, and a pair of protruding pieces 343 extending outward in the X-axis direction from the opening peripheral edge of the main body part 342, 343. The main body portion 342 is arranged so that the connection portion 144 of the positive electrode current collector 14A is positioned at the center of the opening of the main body portion 342 in plan view. A through hole 344 through which the cylindrical portion 311A of the external terminal 31A is inserted is formed at a position overlapping the terminal through hole 240 on the bottom wall (upper end wall) of the main body 342. At the lower end of the projecting piece 343 on the center side in the width direction of the battery 10, a locking portion 345 that is locked to a notch 142 </ b> A provided at the tip portion 142 of the positive electrode current collector 14 </ b> A is formed. Specifically, the locking portion 345 extends downward from the protruding piece 343 so as to pass through the notch 142A of the tip portion 142, and is bifurcated so as to be separated from each other along the Y-axis direction at the lower surface position of the tip portion 142. Divided into In addition, the latching | locking part 345 shown in FIG. 5 is the state before bend | folding (bending) the site | part divided into the forked part in the lower surface position of the front-end | tip part 142. FIG.

  As shown in FIGS. 3 to 8, the plate-shaped deforming portion 341 has a plate shape that spreads so as to close the opening of the main body portion 342, and is connected to the terminal side of the box-shaped support portion 340 and the positive electrode current collector 14 </ b> A. It arrange | positions between 140 A of connection parts. The plate-like deforming portion 341 is deformed so as to bulge toward the inside (in the present embodiment, upward) of the main body portion 342 due to the increase in gas pressure in the case 20 (see FIG. 8). That is, the plate-like deforming portion 341 is a resin-like plate-like member and has a thickness dimension that can bulge toward the inside of the main body portion 342 when the gas pressure in the case 20 rises. Thus, when the gas pressure in the case 20 rises, the plate-like deforming portion 341 moves the engaging portion 35 connected to the plate-like deforming portion 341 to the pressure detecting portion 34 side (specifically, a box shape). To the inside of the support 340).

  Moreover, the plate-shaped deformation part 341 has notches 341A at both ends in the X-axis direction (see FIG. 5). The notch 341A on the center side in the width direction of the battery 10 overlaps with the notch 142A provided at the front end 142 of the positive electrode current collector 14A, and the peripheral edge of the notch 346A is the positive electrode current collector 14A. The front end portion 142 (specifically, the peripheral portion of the notch 142A) is locked by the locking portion 345 of the box-shaped support portion 340. A notch 346A on the outer side in the width direction of the battery 10 is provided at a position overlapping vertically with the through hole 143A provided in the base portion 143 of the terminal side connection portion 140A, and the insulating member 33A, the protruding piece 343 of the box-shaped support portion 340, The peripheral portion of the notch 341A of the plate-shaped deformable portion 341 and the peripheral portion of the through hole 143A in the base portion 143 of the terminal side connecting portion 140A are locked by the locking member 36.

  The engaging portion 35 is disposed on a surface (lower surface in the present embodiment) 346B opposite to the main body portion 342 of the pair of parallel surfaces 346A and 346B at both ends in the thickness direction of the plate-shaped deformable portion 341. Specifically, the engaging portion 35 is provided on the lower surface 346B of the plate-shaped deformable portion 341 at a position corresponding to the center of the opening of the box-shaped support portion 340 (the connecting portion 144 of the terminal side connecting portion 140A). The engaging portion 35 has a hook portion 350 and a connecting portion 351.

  The hook 350 is disposed on the opposite side of the pressure detector 34 with the positive electrode current collector 14A (specifically, the connecting portion 144 of the terminal-side connecting portion 140A) interposed therebetween. The hook portion 350 is connected to the plate-like deformable portion 341 by a connecting portion 351, and when the plate-like deformable portion 341 is deformed by receiving a predetermined gas pressure, the pressure detecting portion 34 side (upward in the example of this embodiment). Move to. The hook part 350 of the present embodiment extends in the Y-axis direction. The hook portion 350 of this embodiment is in contact with the connection portion 144 from below, but may be separated from the connection portion 144.

  The connecting portion 351 hangs down (extends) from a position adjacent to the connecting portion 144 on the lower surface 346B of the plate-shaped deformable portion 341 in the Y-axis direction to a lower end position of the connecting portion 144. A hook portion 350 is connected to the lower end of the connecting portion 351.

  By configuring the engaging portion 35 in this way, the connecting portion 144 is positioned between the plate-shaped deformable portion 341 and the bent portion (the hook portion 350) in the engaging portion 35. Thereby, when the engaging part 35 is pulled up (moved) by deforming so that the plate-like deforming part 341 bulges upward, the connecting part 144 is pulled upward by the hooking part 350 of the engaging part 35. Torn off.

  In the present embodiment, the plate-shaped deformable portion 341 and the engaging portion 35 are integrally formed, but may be separate. In this case, the strength of the plate-shaped deformable portion 341 and the strength of the engaging portion 35 can be easily changed.

  The insulating member 33A is formed of an insulating member such as a resin. The insulating member 33 </ b> A is disposed between the lid body 24 and the box-shaped support portion 340 to insulate the lid body 24 from the box-shaped support portion 340. The insulating member 33 </ b> A of the present embodiment is a plate-like member bent at a plurality of locations, and extends along the surface of the box-shaped support 340 from the upper wall of the main body 342 to the protruding piece 343 on the outer side in the width direction of the battery 10. Have a different shape. The insulating member 33A is provided with a through-hole 330 through which the cylindrical portion 311A is inserted at a position overlapping the terminal through-hole 240 of the lid 24 in the vertical direction.

  The locking member 36 is formed of an insulating material and has a shape in which both end portions of a plate-like member extending vertically are bent in the same direction. The locking member 36 includes an insulating member 33A, a protruding piece 343 of the box-shaped support portion 340, a peripheral portion of the notch 341A in the plate-like deformable portion 341, and a through hole 143A of the base portion 143 between the bent portions. These members are fixed (locked) by sandwiching the peripheral edge. The locking member 36 shown in FIG. 5 is in a state before the lower end portion is bent (bent) at the lower surface position of the distal end portion 142.

  The negative terminal portion 30B is different from the positive terminal portion 30A in that the pressure detector 34, the engaging portion 35, and the locking member 36 are not provided. That is, the negative terminal portion 30B includes an external terminal 31B, a gasket 32, and an insulating member 33B. The external terminal 31B has a solid shaft portion that extends vertically and a flange that extends from the upper end of the shaft portion in the radial direction of the shaft portion. The lower end portion of the external terminal 31B is connected to the negative electrode current collector 14B (specifically, the terminal side connection portion 140B) by being caulked. Unlike the external terminal 31A in the positive electrode terminal portion 30A, the external terminal 31B is not provided with a through-hole penetrating the shaft portion in the axial direction. The insulating member 33B is a plate-like member, and is disposed between the lid body 24 and the terminal side connection portion 140B to insulate the lid body 24 from the terminal side connection portion 140B.

  As described above, when the pressure detection unit 34 is configured by the box-shaped support unit 340 and the plate-shaped deformation unit 341, when the gas is generated in the case 20 and the internal pressure increases, the box-type support unit 340 and the pressure in the space surrounded by the plate-shaped deformable portion 341 (internal space of the pressure detecting portion 34) and the pressure in the space excluding the internal space in the case 20 (the space in which the electrode body 12 is accommodated). A pressure difference therebetween is formed, and the plate-like deformation portion 341 is deformed. As a result, the connecting portion 144 is pulled and pulled by the engaging portion 35 (the hook portion 350), and the positive electrode current collector 14A is divided. That is, the energization path from the external terminal 31A to the electrode body 12 is divided.

  The battery 10 configured as described above is charged by connecting a power source for charging or the like to the pair of external terminals 31A and 31B and applying a voltage. At this time, when the battery 10 is overcharged or an overvoltage is applied to the battery 10, gas is generated in the case 20 due to decomposition or the like of the electrolyte in the case 20. Pressure) increases.

  However, according to the battery 10 of the present embodiment, when the gas is generated and the gas pressure in the case 20 rises, as shown in FIGS. 7 and 8, as shown in FIGS. 341) is deformed, the engaging portion 35 (the hook portion 350) tears the connection portion 144 and the current collector 14A is cut off, so that the energization path leading from the external terminal 31A to the electrode body 12 is cut off. In the example of the present embodiment, the distal end portion 142 and the base portion 143 are divided at the terminal side connection portion 140A of the current collector 14A. Thereby, supply of the electric current from the external terminal 31A to the electrode body 12 can be stopped reliably. As a result, generation of gas due to decomposition of the electrolytic solution in the case 20 can be suppressed, and further increase in gas pressure can be suppressed.

  Further, by making the width dimension of the connection part 144 smaller than the width dimension of the parts (the front end part 142 and the base part 143) adjacent to both sides across the connection part 144, the relationship when the pressure detection part 34 is deformed. By effectively concentrating the pulling force of the joint portion 35 on the connecting portion 144, the connecting portion 144 can be more reliably broken.

  Further, in the battery 10 of the present embodiment, the engaging portion 35 is provided at a position corresponding to the center of the opening of the box-shaped support portion 340 in the plate-shaped deformable portion 341 (a position overlapping in the vertical direction in the example of the present embodiment). . For this reason, when the plate-shaped deforming portion 341 is deformed due to a pressure difference between the inside and the outside of the pressure detecting portion 34, the force with which the engaging portion 35 pulls the connecting portion 144 is maximized. Thereby, when gas is generated in the case 20 due to overcharge, overvoltage, etc. and the gas pressure rises, the current collector 14A is more reliably divided.

  Further, in the battery 10 of the present embodiment, the outside of the case 20 and the internal space of the pressure detection unit 34 (by the box-shaped support unit 340 and the plate-shaped deformation unit 341) through a through hole defined by the inner peripheral surface 313 of the external terminal 31A. The enclosed space). For this reason, the pressure in the internal space of the pressure detector 34 can be maintained at the external pressure regardless of the temperature in the case 20 (in other words, the pressure in the internal space of the pressure detector 34 can be made substantially constant). . Thereby, the value of the gas pressure in the case 20 when the current collector 14A is divided can be made constant. That is, the pressure in the internal space of the pressure detection unit 34 varies depending on the ambient temperature of the pressure detection unit 34, and the variation causes the value of the gas pressure in the case 20 when the current collector 14A is divided. Can be prevented.

  Moreover, in the battery 10 of this embodiment, the plate-shaped deformation part 341 and the engagement part 35 that divide the current collector 14A are made of resin. For this reason, it is ensured that the distal end portion 142 and the base portion 143 are electrically connected through the plate-shaped deformable portion 341 and the engaging portion 35 in the separated current collector 14A (terminal side connection portion 140A in the example of the present embodiment). Can be prevented.

  Further, in the battery 10 of the present embodiment, the connection portion 144 of the terminal side connection portion 140A has a gas pressure value (when the gas discharge valve 242 is opened (operated) and the gas pressure in the case 20 is higher than the normal pressure). When the second value is smaller than the first value, it is torn off by the engaging portion 35. For this reason, in the battery 10, the current collector 14 </ b> A is divided before the gas in the case 20 rises to the gas pressure (the value of the gas pressure) discharged from the gas discharge valve 242 to the outside, and from the outside to the electrode body 12. Current supply stops. Thereby, before the gas discharge valve 242 opens (actuates), the generation of gas due to the supply of current to the electrode body 12 can be suppressed, and the gas pressure can be prevented from rising. In addition, even when the gas pressure continues to rise after the supply of current to the electrode body 12 is stopped, the gas discharge valve 242 discharges the gas to the outside when the gas pressure rises to the first value. The rupture of the case 20 due to the pressure increase can be prevented more reliably.

  In addition, the electrical storage element of this invention is not limited to the said embodiment, Of course, a various change can be added in the range which does not deviate from the summary of this invention.

  In the battery 10 of the above-described embodiment, the pressure detection unit 34 is provided only in the positive electrode terminal unit 30A, but is not limited to this configuration. The pressure detection part 34 may be provided only in the terminal part 30B for negative electrodes, or both the terminal part 30A for positive electrodes and the terminal part 30B for negative electrodes. In these cases, similarly to the terminal-side connecting portion 140A on the positive electrode side, the tip portion 142, the base portion 143, and the connecting portion 144 are provided in the terminal-side connecting portion 140B of the current collector 14B for the negative electrode.

  In the battery 10 of the above-described embodiment, the engaging portion 35 is moved and the current collector 14A is divided by a part of the pressure detecting portion 34 (plate-like deforming portion 341) being deformed. However, the configuration is not limited to this. . For example, when a predetermined pressure is applied to the pressure detection unit 34, a part of the pressure detection unit 34 moves, and the engagement unit 35 (the hooking unit 350) moves to the pressure detection unit 34 side in conjunction with the movement. It may be.

  In the battery 10 of the above embodiment, the pressure detection unit 34 is disposed between the case 20 and the current collector 14A. However, even if the pressure detection unit 34 is disposed on the inner side of the case 20 than the current collector 14A. Good. Also in this case, the hooking unit 350 is configured to move toward the pressure detection unit 34 when a predetermined gas pressure is applied to the pressure detection unit 34.

  The specific shape of the engaging part 35 provided in the plate-shaped deformation part 341 is not limited. Although the engaging part 35 of the said embodiment is substantially L-shaped, for example, the shape etc. which surround the connection part 144 in the circumferential direction may be sufficient. Moreover, although the engaging part 35 of the said embodiment is not mutually fixed by the connection part 144 and adhesion | attachment etc., the engagement part 35 and the connection part 144 may be mutually adhere | attached by adhesion | attachment etc., for example. That is, the engaging portion 35 may be configured to be able to tear the connection portion 144 when the pressure detecting portion 34 (specifically, the plate-like deforming portion 341) is deformed and moves to the pressure detecting portion 34 side. .

  In the battery 10 of the above embodiment, when the current collector 14A is divided, the energization path leading from the external terminal 31A to the electrode body 12 is divided, thereby supplying current from the external terminal 31A to the electrode body 12. Although it is the structure to stop, it is not limited to this structure. For example, the battery 10 has a configuration in which a part of the current collector 14A is stretched to increase the electrical resistance of the portion, thereby reducing the energization state of the energization path from the external terminal 31A to the electrode body 12. May be. Details are as follows.

  In the current collector 14, a portion between the electrode-side connection portion 141 and the portion of the terminal-side connection portion 140A that is connected to the external terminal 31A (terminal portion 30A) so as to be conductive is extended. Since the stretched portion has a small cross-sectional area, the electrical resistance of the portion increases (rises). For this reason, the energization state of a part of the energization path (extended portion) leading from the external terminal 31A to the electrode body 12 is lowered, and thereby the supply of current from the external terminal 31A to the electrode body 12 is extremely low. Can do. As described above, even if the current collector 14 is not divided, a part of the current collector 14 is extended (the cross-sectional area is reduced) to suppress the supply of current from the external terminal 31A to the electrode body 12, thereby reducing the gas in the case 20 The structure which suppresses generation | occurrence | production etc. may be sufficient.

  In the terminal-side connecting portion 140A of the current collector 14A, the width dimension (dimension in the Y-axis direction) of the connecting portion 144 is smaller than the width dimensions of the distal end portion 142 and the base portion 143 adjacent to both sides of the connecting portion 144. However, it is not limited to this configuration. If the connecting portion 144 is easily torn off by the engaging portion 35 when the pressure detecting portion 34 (a part of the pressure detecting portion 34) is deformed, the width dimension of the connecting portion 144 and both sides of the connecting portion 144 are used. The width dimensions of the portions (the tip portion 142 and the base portion 143) may be the same. For example, a configuration in which the strength of the connecting portion 144 is smaller than the strength of the portions adjacent to both sides of the connecting portion 144 is used.

  Further, in the battery 10 of the above-described embodiment, the pressure detection unit 34 (specifically, the box-shaped support unit 340) configures a part of the energization path from the external terminal 31A to the electrode body 12, but is limited to this configuration. Not. The box-shaped support part 340 may be arranged so as not to be included in the energization path. In this case, the box-shaped support part 340 may be comprised by the member which has insulation.

  In the battery 10 of the above-described embodiment, the inner peripheral surface 313 of the external terminal 31A configures a communication unit that communicates the outside of the case 20 and the internal space of the pressure detection unit 34, but is not limited to this configuration. The communication part may be constituted by other members (parts). Further, in the battery 10 of the above embodiment, the outside of the case 20 and the internal space of the pressure detection unit 34 communicate with each other, but they do not have to communicate with each other. That is, the pressure detection unit 34 may be sealed (sealed). Even in this case, when the gas pressure in the case 20 rises, a pressure difference is generated between the pressure in the pressure detection unit 34 and the pressure in the case 20, thereby deforming the plate-like deformation unit 341. The connecting portion 144 is broken.

  Moreover, in the said embodiment, although the secondary battery (lithium ion secondary battery) which can be charged / discharged was demonstrated, the kind and magnitude | size (capacity | capacitance) of a battery are arbitrary. Moreover, in the said embodiment, although the lithium ion secondary battery was demonstrated as an example of an electrical storage element, it is not limited to this. For example, the present invention can be applied to various secondary batteries, other primary batteries, and power storage elements of capacitors such as electric double layer capacitors.

10 Battery (storage element)
12 Electrode bodies 14A and 14B Current collectors 140A and 140B Terminal side connection portion 141 Electrode body side connection portion (second part)
142 Tip (first part)
143 Base 144 Connection part (intermediate part)
20 Case 242 Gas exhaust valve 30A, 30B Terminal part 31A, 31B External terminal 313 Inner peripheral surface (communication part)
34 Pressure detection part 340 Box-shaped support part 341 Plate-shaped deformation part 350 Hook part S Internal space

Claims (7)

An electrode body;
A case for housing the electrode body;
An external terminal attached to the case;
A current collector that connects the electrode body and the external terminal in a conductive manner;
A pressure receiving portion to which the gas pressure in the case is applied;
A region on the opposite side of the pressure receiving part across the current collector, between the first part connected to the external terminal and the second part connected to the electrode body in the current collector A hook disposed in a region adjacent to the site;
A box-shaped support part that has a box shape having an opening and supports the pressure receiving part;
The pressure receiving portion is a plate-like deformation portion having a plate shape that closes the opening of the box-shaped support portion, and the hook-like deformation portion is connected to a surface opposite to the box-shaped support portion. Have
The power storage element, wherein the plate-like deforming portion is deformed so as to bulge toward the inside of the box-shaped support portion due to an increase in the gas pressure .   The power storage element according to claim 1, wherein a width dimension of the intermediate part is smaller than a width dimension of parts adjacent to both sides of the intermediate part across the intermediate part. 3. The power storage device according to claim 1, wherein the hooking portion is connected to a position corresponding to the center of the opening of the box-shaped support portion on the opposite surface of the plate-shaped deformation portion. element. And outside of the casing, characterized in that it further comprises a communication portion for communicating the space surrounded by the box-like supporting portion and the plate-like deformed portion, according to any one of claims 1 to 3 Power storage element. The plate-like deformable portion and said hook portion is characterized by being composed of a resin, the electric storage device according to any one of claims 1-4. The case has a gas discharge valve for discharging the gas in the case to the outside when the gas pressure becomes a first value or more,
The intermediate portion is torn off by the hook when the gas pressure in the case is a second value higher than normal pressure and smaller than the first value. The electricity storage device according to any one of 5 . An electrode body;
A case for housing the electrode body;
An external terminal attached to the case;
A current collector that connects the electrode body and the external terminal in a conductive manner;
A pressure receiving portion to which the gas pressure in the case is applied;
A hook portion disposed on the opposite side of the pressure receiving portion with the current collector interposed therebetween, and moves to the pressure receiving portion side when a predetermined gas pressure is applied to the pressure receiving portion. A storage element, comprising: a hook portion that tears an intermediate portion between a first portion connected to the external terminal and a second portion connected to the electrode body.

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