JP5837468B2 - Sealed battery - Google Patents

Description

  The present invention relates to a structural technology for a sealed battery.

  The sealed battery is configured by enclosing an electrode body including a positive electrode and a negative electrode together with an electrolyte in a battery case, and for example, a lithium ion secondary battery is well known. In a sealed battery, a current interruption mechanism that detects overcharge and interrupts current may be provided. As one of such current interrupting mechanisms, a pressure type current interrupting mechanism that physically interrupts current when the internal pressure of the battery case becomes higher than a set pressure is known (for example, Patent Document 1).

  However, in a sealed battery, once the pressure-type current interruption mechanism is activated, the conduction path is interrupted and charging / discharging becomes impossible. Therefore, when disposing of a sealed battery in which the pressure-type current interrupting mechanism is activated, it must be transported in an overcharged state. Therefore, in order to ensure reliable safety during transportation, it is necessary to perform the discharge process by returning the conduction path of the pressure-type current interruption mechanism again.

JP 2010-212034 A

  The problem to be solved by the present invention is to provide a sealed battery capable of returning the conduction path of the pressure type current interruption mechanism again.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

That is, according to the first aspect of the present invention, the reversing plate is interposed between the external terminal of the battery case and the current collecting terminal disposed inside the battery case, and the reversing plate is deformed according to the pressure increase inside the battery case. Thus, the sealed battery having a pressure type current interrupting device that electrically disconnects the external terminal and the current collecting terminal, after the pressure type current interrupting mechanism is activated, Applying pressure, comprising a conduction return mechanism for electrically connecting the external terminal and the current collecting terminal ,
The external terminal includes a screw hole portion that communicates the inner side and the outer side of the battery case, and the conduction return mechanism is deformed by tightening a bolt that is screwed into the screw hole portion of the external terminal. The pressing plate is configured to apply a pressing force .

  According to the sealed battery of the present invention, the conduction path of the pressure type current interruption mechanism can be restored again.

The schematic diagram which showed the structure of the lithium ion secondary battery. The schematic diagram which similarly showed the structure of the pressure type electric current interruption mechanism and the conduction | electrical_connection return mechanism. The schematic diagram which similarly showed the effect | action of the pressure type electric current interruption mechanism and the conduction | electrical_connection return mechanism. The schematic diagram which shows the flow of a conduction | electrical_connection return process.

The configuration of the lithium ion secondary battery 100 will be described with reference to FIG.
In FIG. 1, in order to make the internal configuration of the lithium ion secondary battery 100 easier to understand, the lithium ion secondary battery 100 is schematically shown in partial cross-sectional view.

  The lithium ion secondary battery 100 is an embodiment according to the sealed battery of the present invention. The lithium ion secondary battery 100 includes a battery case 15, a sealing plate 16, a positive electrode terminal 11, and a negative electrode terminal 12.

  The battery case 15 is configured as a rectangular parallelepiped case having an open top surface. The battery case 15 contains a flat wound electrode body 20 and an electrolytic solution. The sealing plate 16 closes the opening of the battery case 15. The sealing plate 16 is provided with a positive electrode terminal 11 and a negative electrode terminal 12. A part of the positive electrode terminal 11 and the negative electrode terminal 12 protrudes to the surface side of the sealing plate 16.

  Inside the battery case 15 whose opening is closed by the sealing plate 16, a positive current collecting terminal 51 and a negative current collecting terminal 52, which are connected to the positive terminal 11 and the negative terminal 12, respectively, are connected. doing.

  The wound electrode body 20 is configured by winding a long sheet-like positive electrode sheet and a long sheet-like negative electrode sheet with a width direction as an axial direction via a long sheet-like separator. is there. A positive electrode current collector 21 is exposed at the end of the wound electrode body 20 on one side in the axial direction. On the other hand, the negative electrode current collector 22 is exposed at the end of the wound electrode body 20 on the other side in the axial direction.

  The positive electrode current collecting terminal 51 has a leg portion 51 </ b> B extending downward. The positive electrode current collector 21 is joined to the leg 51B. Similarly, the negative electrode current collecting terminal 52 has a leg portion 52 </ b> B extending downward. The negative electrode current collector 22 is joined to the leg portion 52B.

  A pressure-type current interruption mechanism 30 is interposed between the positive electrode terminal 11 and the positive electrode current collecting terminal 51. The positive electrode terminal 11 is electrically connected to the positive electrode current collector 21 of the wound electrode body 20 via the pressure-type current interrupt mechanism 30 and the positive electrode current collector terminal 51. The negative electrode terminal 12 is electrically connected to the negative electrode current collector 22 of the wound electrode body 20 via the negative electrode current collector terminal 52. The pressure type current interrupt mechanism 30 will be described later in detail.

The configuration of the pressure type current interrupting mechanism 30 and the bolt 40 as the conductive return mechanism provided between the positive electrode terminal 11 and the positive electrode current collecting terminal 51 will be described with reference to FIG.
In FIG. 2, for easy understanding, the positive electrode terminal 11, the pressure type current interruption mechanism 30, and the positive electrode current collecting terminal 51 are schematically shown in partial cross-sectional view.

  The positive electrode terminal 11 includes a connection terminal 31 as an external terminal, a gasket 32, an insulating plate 33, a lead 34, and a bolt 40 as a conductive return mechanism.

  The connection terminal 31 is configured in a hollow rivet shape, and includes a cylinder portion 31A, a screw hole portion 31B, and a tip portion 31C. The connection terminal 31 is formed by inserting the cylindrical portion 31A into the holes formed in the gasket 32, the sealing plate 16, the insulating plate 33, and the lead 34, and caulking the tip portion 31C. The plate 16, the insulating plate 33, and the lead 34 are fixed integrally. The connection terminal 31 is electrically connected to the lead 34 by the tip portion 31C.

  The bolt 40 is screwed into the screw hole portion 31 </ b> B of the connection terminal 31. The bolt 40 is screwed into the screw hole 31B of the connection terminal 31 with a predetermined gap provided between a bottom surface 40A of the bolt 40 and a recess 35B of the reversing plate 35 described later. Note that the predetermined gap means that even if the pressure-type current interrupting mechanism 30 is activated and the reversing plate 35 is deformed so as to warp in the pressurizing direction (upward), The gap is such that it does not come into contact with the recess 35 </ b> B of the reversing plate 35. Further, by rotating the bolt 40, it is possible to change the distance between the bottom surface 40A of the bolt 40 and the recess 35B of the reversing plate 35.

  The gasket 32 is made of resin and has a concave shape that is recessed downward. The gasket 32 is interposed between the connection terminal 31 and the sealing plate 16 and electrically insulates the connection terminal 31 and the sealing plate 16.

  The insulating plate 33 is made of resin and has a concave shape that is recessed upward. The insulating plate 33 is interposed between the sealing plate 16 and the lead 34 and electrically insulates the sealing plate 16 and the lead 34.

  The lead 34 is made of aluminum and is formed in a recessed shape that is recessed upward, and a flat edge 34 </ b> A extending radially outward is formed at the lower end of the peripheral edge.

  The positive electrode current collecting terminal 51 is made of aluminum and includes a main body 51A, a leg portion 51B, a thin portion 51C, and a marking portion 51D. The main body 51A is formed in a substantially rectangular shape in plan view. A substantially circular thin portion 51C is formed at a substantially central portion of the main body 51A. An engraved portion 51D is formed in the thin portion 51C. The engraved part 51D is a groove formed in a substantially circular shape on the lower surface of the thin part 51C.

  The pressure-type current interrupting mechanism 30 includes an inversion plate 35, an insulator 36, and a thin portion 51 </ b> C of the positive electrode current collecting terminal 51. The pressure-type current interrupting mechanism 30 electrically interrupts the positive electrode terminal 11 and the positive electrode current collecting terminal 51 in the battery case 15 by the reversal plate 35 being deformed upward in response to the pressure increase in the battery case 15. Is.

  The reversing plate 35 is made of aluminum, is formed in a substantially disk shape, and includes a main body 35A and a recess 35B. The reversing plate 35 is a member that deforms so as to warp in the pressurizing direction (upward) when the internal pressure of the battery case 15 becomes equal to or higher than the set pressure.

  The peripheral portion of the main body 35A is joined to the edge portion 34A of the lead 34 by welding, and the main body 35A and the lead 34 are electrically connected. As a result, the connection terminal 31 and the reverse plate 35 are electrically connected via the lead 34. The reversing plate 35 is interposed between the lead 34 and the insulator 36.

  The recess 35B is formed in a substantially central portion of the main body 35A, and is formed so that the upper surface side is recessed downward. The bottom surface of the recess 35 </ b> B is joined by welding to the upper surface of the portion inside the stamped portion 51 </ b> D in the thin-walled portion 51 </ b> C of the positive electrode current collecting terminal 51. When the reversal plate 35 is deformed upward due to an increase in pressure inside the battery case 15, the deformation causes the thin portion 51C of the positive electrode current collecting terminal 51 to be pulled upward, and the thin portion 51C is broken at the stamped portion 51D. Become.

  The insulator 36 is made of resin and has a substantially disk shape. The insulator 36 is interposed between the reversing plate 35 and the positive current collecting terminal 51, and insulates the reversing plate 35 and the positive current collecting terminal 51 (however, the concave portion 35B of the reversing plate 35 and the positive current collecting terminal 51). (Excluding the welded portion with the thin-walled portion 51C).

The operation of the pressure-type current interruption mechanism 30 and the conduction return mechanism (bolt 40) will be described with reference to FIG.
In FIG. 3, for ease of explanation, the pressure type current interrupt mechanism 30 is schematically shown in a partial cross-sectional view. 3A shows a state before the operation of the pressure-type current interrupting mechanism 30, FIG. 3B shows a state after the operation of the pressure-type current interrupting mechanism 30, and FIG. The state after the operation of the conduction return mechanism (bolt 40) is shown.

  As shown in FIG. 3A, it is assumed that the lithium ion secondary battery 100 is overcharged. When the lithium ion secondary battery 100 is overcharged, the components in the electrolytic solution are decomposed, and the internal pressure of the battery case 15 increases. As the internal pressure of the battery case 15 increases, upward pressure acts on the pressure-type current interrupt mechanism 30.

  When the upward pressure acts on the pressure-type current interrupting mechanism 30, the upward pressure also acts on the reversing plate 35, and the reversing plate 35 is deformed to warp upward. By deforming the reversing plate 35 so as to warp upward, the thin portion 51C of the positive electrode current collecting terminal 51 is pulled upward. When the thin-walled portion 51C of the positive electrode current collecting terminal 51 is pulled upward, the engraving portion 51D of the positive electrode current collecting terminal 51 is broken.

  As shown in FIG. 3 (B), upward pressure acts on the pressure-type current interrupting mechanism 30 to apply a force that pulls the thin-walled portion 51C upward, and the positive current collector terminal 51 borders the stamped portion 51D. As a result, the electrical connection between the reversing plate 35 and the positive current collecting terminal 51 is interrupted. By disconnecting the electrical connection between the reversing plate 35 and the positive current collecting terminal 51, the positive electrode terminal 11 side and the positive current collecting terminal 51 side of the pressure type current interruption mechanism 30 are electrically insulated.

  As shown in FIG. 3C, the bolt 40 is tightened in a state where the pressure-type current interruption mechanism 30 is activated and the conduction path (the conduction path between the positive electrode terminal 11 and the positive electrode current collecting terminal 51) is interrupted ( Rotating operation is performed in the tightening direction (the direction in which the distance between the bottom surface 40A of the bolt 40 and the recess 35B of the reversing plate 35 decreases). The tightened bolt 40 is lowered and the concave portion 35B of the reversing plate 35 is pressed by the bottom surface 40A of the bolt 40.

  By pressing the recess 35B of the reversing plate 35, the reversing plate 35 that has been deformed so as to warp upward is restored to its original shape. When the reversing plate 35 is restored to the original shape, the thin portion 51C separated by the marking portion 51D is joined. By joining the separated thin portion 51C, the electrical connection between the reversing plate 35 and the positive electrode current collecting terminal 51 is restored. When the electrical connection between the reversing plate 35 and the positive current collecting terminal 51 is restored, the positive electrode terminal 11 side and the positive current collecting terminal 51 side of the pressure type current interrupt mechanism 30 are electrically restored.

The effect of the conduction return mechanism (bolt 40) will be described.
According to the bolt 40, the conduction path of the pressure-type current interruption mechanism 30 can be restored.
Therefore, the discharge process can be performed by returning the conduction path of the lithium ion secondary battery 100 in which the pressure-type current interrupting mechanism 30 is operated again.

  In the lithium ion secondary battery 100 of the present embodiment, the positive electrode terminal 11 is provided with the pressure-type current interruption mechanism 30 and the bolt 40, but is not limited thereto. For example, the pressure type current interruption mechanism 30 and the bolt 40 may be provided on the negative electrode terminal 12.

Next, another embodiment of the conductive return mechanism will be described.
The conductive return mechanism in the present embodiment includes a hose 60 connected to the connection terminal 31 and a compressor (not shown) that encloses high-pressure air from the hose 60 through the screw hole 31B of the connection terminal 31 into the battery case 15. It is equipped with.

With reference to FIG. 4, the conduction return step S <b> 100 for returning the conduction path of the pressure type current interrupt mechanism 30 by the conduction return mechanism having such a configuration will be described.
In FIG. 4, each step of the conduction return step S100 is schematically shown in partial cross-sectional view.

  In step S110, it is assumed that the lithium ion secondary battery 100 is overcharged. When the lithium ion secondary battery 100 is overcharged, the components in the electrolytic solution are decomposed, and the internal pressure of the battery case 15 increases. As the internal pressure of the battery case 15 increases, upward pressure acts on the pressure-type current interrupt mechanism 30.

  In step S120, an upward pressure acts on the pressure-type current interrupting mechanism 30, whereby an upward pressure also acts on the reversing plate 35, and the reversing plate 35 is deformed to warp upward. By deforming the reversing plate 35 so as to warp upward, the thin portion 51C of the positive electrode current collecting terminal 51 is pulled upward. When the thin-walled portion 51C of the positive electrode current collecting terminal 51 is pulled upward, the engraving portion 51D of the positive electrode current collecting terminal 51 is broken.

  An upward pressure acts on the pressure-type current interrupting mechanism 30 to apply a force that pulls the thin portion 51C upward, and the positive current collecting terminal 51 is separated into an inner side and an outer side with the stamped portion 51D as a boundary, and is reversed. The electrical connection between the plate 35 and the positive electrode current collecting terminal 51 is interrupted. By disconnecting the electrical connection between the reversing plate 35 and the positive current collecting terminal 51, the positive electrode terminal 11 side and the positive current collecting terminal 51 side of the pressure type current interruption mechanism 30 are electrically insulated.

  In step S <b> 130, the hose 60 is connected to the connection terminal 31, and high-pressure air is sealed inside the battery case 15 by the hose 60. Note that the other end of the hose 60 is connected to a compressor (not shown).

  In step S140, the recessed portion 35B of the reversing plate 35 is pressed by the sealed high pressure air. When the recess 35B of the reversing plate 35 is pressed, the reversing plate 35 that has been deformed so as to warp upward is restored to its original shape. When the reversing plate 35 is restored to the original shape, the thin portion 51C separated by the marking portion 51D is joined.

  By joining the separated thin portion 51C, the electrical connection between the reversing plate 35 and the positive electrode current collecting terminal 51 is restored. When the electrical connection between the reversing plate 35 and the positive current collecting terminal 51 is restored, the positive electrode terminal 11 side and the positive current collecting terminal 51 side of the pressure type current interrupt mechanism 30 are electrically restored.

The effect of the conduction return step S100 will be described.
According to the continuity return step S100, the continuity path of the pressure-type current interrupt mechanism 30 can be returned. Therefore, the discharge process can be performed by returning the conduction path of the lithium ion secondary battery 100 in which the pressure-type current interrupting mechanism 30 is operated again.

11 Positive terminal 30 Pressure type current interruption mechanism 31 Connection terminal (external terminal)
35 Reversing plate 35B Concave part 40 Volt 51 Positive electrode current collecting terminal 51C Thin part 100 Lithium ion secondary battery

Claims (1)

The interposer is interposed between an external terminal of the battery case and a current collecting terminal disposed inside the battery case, and a reversing plate is deformed in response to a pressure increase inside the battery case, so that the external terminal and the current collector are deformed. A sealed battery equipped with a pressure-type current interrupting device that electrically disconnects the electrical terminal;
After the pressure-type current interrupting mechanism is activated, a pressing force is applied to the deformed reversing plate, and a conduction return mechanism for electrically connecting the external terminal and the current collecting terminal is provided .
The external terminal includes a screw hole that communicates the inside and the outside of the battery case,
The conduction return mechanism is configured to apply a pressing force to the deformed reversal plate by tightening a bolt screwed into a screw hole portion of the external terminal.
Sealed battery.

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