JP2014077674A - Leak inspection method for current shut-off valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a leak inspection method for a current shut-off valve, configured to perform leak inspection in a short time.SOLUTION: A current shut-off valve 50 includes a through hole 51c allowing communication between the inside and outside of an outer sheath 10 of a battery 1, and having one end to which an inversion plate 53 is attached. A leak inspection method for the current shut-off valve 50, configured to perform leak inspection of the bottom of the through hole 51c includes: inserting a fixing component 110 for fixing the inversion plate 53 from the top of the through hole 51c; covering the top of the through hole 51 to form a sealed space S; and applying vacuum treatment to the sealed space S to perform leak inspection of the bottom of the through hole 51c.

Description

  The present invention relates to a leakage check method for a current cutoff valve that performs a leakage check for a current cutoff valve.

Conventionally, some sealed batteries such as lithium ion batteries include a current cutoff valve that detects that the internal pressure in the exterior has exceeded a predetermined level and cuts off the current.
The current cutoff valve is installed in a sealing body that seals the battery case of the exterior. The current cutoff valve has a through hole that communicates the outside and the inside of the exterior. The outer peripheral edge of the reversing plate is joined to one end of the through hole by welding, and the current collector is located at the center of the reversing plate Are connected by welding to form a current cutoff valve. One end side of the through hole is hermetically sealed by welding the outer peripheral edge of the reversing plate all around.
When the internal pressure in the exterior exceeds a predetermined level, the current cutoff valve deforms the reversal plate due to the pressure difference between the internal pressure in the exterior and the internal pressure in the through hole, and disconnects the junction between the current collector and the reversal plate. Interrupt the current.

  In the battery manufacturing process, in order to reliably operate such a current cutoff valve, after welding the outer peripheral edge portion of the reversing plate to one end side of the through hole, the welded portion between one end side of the through hole and the reversing plate It is necessary to perform a leak inspection.

  In the technique disclosed in Patent Document 1, gas is introduced into the inside of the through hole after welding the outer peripheral edge of the reversing plate to the sealing body tab (one end side of the through hole). Based on the amount of gas leaked from the welded portion, the sealed state of the welded portion between the sealing body tab and the reverse plate is inspected.

JP 2010-212034 A

In the technique disclosed in Patent Document 1, in order to measure the amount of gas leaked from the welded portion between the sealing body tab and the reversing plate, it is necessary to make the outside of the through hole a vacuum. That is, in Patent Document 1, after introducing gas into the inside of the through hole, the other end side of the through hole (the side opposite to the side on which the reverse plate is welded) is sealed, and the sealing body is placed in the chamber. Must be evacuated.
In this case, it is necessary to evacuate the chamber large enough to contain the sealing body.

  That is, in the technique disclosed in Patent Document 1, it is necessary to perform vacuum processing on a large volume of space, and the time for performing vacuum processing becomes longer, so that the leak inspection takes time. For this reason, in patent document 1, the installation number of the equipment which performs a leak test | inspection will increase, As a result, the production cost of a sealed battery will increase.

  The present invention has been made in view of the above situation, and provides a leakage check method for a current cutoff valve capable of performing a leak check in a short time.

  According to claim 1, a leak on one end side of the through hole of a current cutoff valve in which a through hole is formed to communicate the inside and outside of the battery exterior and an inversion plate is attached to one end side of the through hole. A leakage check method for a current cutoff valve that performs inspection, wherein a fixing member that fixes the reversing plate is inserted from the other end side of the through hole, and a sealed space is formed to cover the other end side of the through hole. A leak test is performed on one end side of the through hole by performing a vacuum process on the sealed space.

  The present invention has an effect that a leak inspection can be performed in a short time.

Sectional drawing which shows the battery which comprises an electric current cutoff valve. The expanded sectional view which shows an electric current cutoff valve. The expanded sectional view which shows the state which the electric current cutoff valve act | operated. Explanatory drawing which shows a mode that a sealing body is set to a measurement case. Explanatory drawing which shows a mode that the space inside an inversion board is made into sealed space. Explanatory drawing which shows a mode that vacuum processing is performed with respect to sealed space. Explanatory drawing which shows a mode that helium is introduce | transduced into a measurement case.

  Below, the leakage check method of the current cutoff valve of this embodiment will be described.

First, the configuration of the battery 1 including the current cutoff valve 50 will be described with reference to FIG.
In addition, in this embodiment, although the battery 1 shall be a lithium ion battery, it is not limited to this.

  The battery 1 includes an exterior 10, a wound electrode body 20, a negative current collector terminal 30, a positive current collector terminal 40, a current cutoff valve 50, and the like.

  The exterior 10 is configured as a rectangular parallelepiped case having a battery case 11 and a sealing plate 12.

  The battery case 11 is a bottomed cylindrical prism-shaped member having an open upper surface, and houses the wound electrode body 20 therein. An electrolytic solution is injected into the battery case 11.

The sealing plate 12 is a flat rectangular member having a shape corresponding to the opening surface of the battery case 11, and is joined to the battery case 11 while closing the opening surface of the battery case 11.
The sealing plate 12 supports the negative electrode terminal 13 and the positive electrode terminal 14 via external terminals 15 and 16 formed of a conductive member and insulating members 17 and 18 formed of resin.

A part of the negative electrode terminal 13 and the positive electrode terminal 14 protrudes to the surface side (upper side) of the sealing plate 12.
The insulating members 17 and 18 are interposed between the external terminals 15 and 16 and the sealing plate 12 to electrically insulate the external terminals 15 and 16 from the sealing plate 12.

  The wound electrode body 20 is configured by winding a negative electrode sheet and a positive electrode sheet each formed in a long sheet shape with a width direction as an axial direction through a separator formed in a long sheet shape. The wound electrode body 20 is formed into a flat shape by being pressed after winding the positive electrode sheet, the negative electrode sheet, and the separator. In the wound electrode body 20, the negative electrode current collector 21 and the positive electrode current collector 22 are exposed from both ends in the axial direction.

The negative electrode current collecting terminal 30 is formed using copper as a material, and is disposed below the sealing body 12 and on the left side of the battery case 11. The negative electrode current collecting terminal 30 is formed with a leg portion 32 extending downward from the left end portion of the main body 31. The negative electrode current collector terminal 30 is electrically connected to the wound electrode body 20 by joining the negative electrode current collector 21 to the leg portion 32.
The negative electrode terminal 13 is electrically connected to the negative electrode current collector 21 of the wound electrode body 20 via the external terminal 15 and the negative electrode current collector terminal 30.

As shown in FIGS. 1 and 2, the positive electrode current collector terminal 40 is formed using aluminum as a material, and is disposed below the sealing body 12 and on the right side of the battery case 11. The positive current collecting terminal 40 is formed with a leg portion 42 that extends downward from the right end portion of the main body 41. The positive electrode current collector terminal 40 is electrically connected to the wound electrode body 20 by joining the positive electrode current collector 22 to the leg portion 42.
The current cutoff valve 50 is interposed between the positive current collector terminal 40 and the positive terminal 14. That is, the positive electrode terminal 14 is electrically connected to the positive electrode current collector 22 of the wound electrode body 20 via the external terminal 16, the current cutoff valve 50, and the positive electrode current collector terminal 40.

  Next, the configuration of the current cutoff valve 50 will be described with reference to FIG.

  The current cutoff valve 50 detects that the internal pressure in the exterior 10 has exceeded a predetermined level and cuts off the current. The current cutoff valve 50 includes a rivet 51, an upper insulating member 52, a reversing plate 53, and a lower insulating member 54.

  The rivet 51 is a substantially cylindrical member having a lower inner diameter dimension and an outer diameter dimension that are larger than the upper inner diameter dimension and the outer diameter dimension. In such a rivet 51, a small diameter part 51a, a large diameter part 51b, and a through hole 51c are formed.

  The small diameter part 51 a is a small diameter part formed on the upper side of the rivet 51.

  The large diameter portion 51b is a portion formed below the rivet 51 and having a larger diameter than the inner diameter size and the outer diameter size of the small diameter portion 51a.

  The through hole 51c is a hole having a substantially circular shape in plan view that penetrates substantially the center of the rivet 51 in the vertical direction.

The rivet 51 is formed by caulking the external terminal 16, the insulating member 18, the sealing body 12, and the upper insulating member 52 with the small diameter portion 51a and the large diameter portion 51b, so that the external terminal 16, the insulating member 18, the sealing body 12, And the upper insulating member 52 is fixed integrally.
Thereby, the rivet 51 is electrically connected to the external terminal 16.

  At this time, a predetermined gap is formed between the small diameter portion 51 a and the sealing body 12 along the radial direction of the rivet 51. Further, the through hole 51 c communicates the inside and the outside of the exterior 10 of the battery 1.

  That is, the through hole 51c of the present embodiment functions as a through hole formed in the current cutoff valve according to the present invention.

  The upper insulating member 52 is formed of resin as a material, and is formed in a recessed shape that is recessed upward. The upper insulating member 52 is interposed between the sealing plate 12 and the large diameter portion 51 b of the rivet 51 and electrically insulates the sealing plate 12 and the rivet 51.

  The inversion plate 53 is formed in a substantially disc shape using aluminum as a material. A concave portion 53a is formed at a substantially central portion of the reversing plate 53 to be a portion where the upper surface side is recessed. The reversing plate 53 is joined at its outer peripheral edge to the lower end of the large-diameter portion 51b of the rivet 51 by welding, and is electrically connected to the rivet 51 (see the welded portion 53b shown in FIG. 2).

At this time, the outer peripheral edge portion of the reversing plate 53 is welded over the entire circumference without any gap, and the lower side of the through hole 51c is sealed.
Thereby, the through-hole 51c and the inner side of the exterior 10 are formed as separate spaces with the reversing plate 53 therebetween (see FIG. 1).

  Thus, the current cutoff valve 50 has the reversing plate 53 attached to the lower side (one end side) of the through hole 51c.

  Hereinafter, the upper side of the reversing plate 53, that is, the through hole 51c side is referred to as “inside of the reversing plate 53”. Further, the lower side of the reversing plate 53, that is, the positive electrode current collecting terminal 40 side is referred to as “outside of the reversing plate 53”.

  When the pressure outside the reversing plate 53 becomes higher than the pressure inside the reversing plate 53, the reversing plate 53 is deformed so as to warp along the pressing direction (the direction from the outside to the inside of the reversing plate 53). Configured to be possible.

The lower insulating member 54 is formed of a resin as a raw material, and is formed in a disk shape in which a hole is formed in the central portion. A recess 53 a of the reversing plate 53 is disposed in the hole of the lower insulating member 54.
The lower insulating member 54 is interposed between the large-diameter portion 51b of the rivet 51 and the reversing plate 53 and the positive current collecting terminal 40, and the portion other than the concave portion 53a of the rivet 51 and the reversing plate 53, and the positive current collecting The terminal 40 is electrically insulated.

In order to operate such a current cutoff valve 50, a notch portion 43 and a connection portion 44 are formed in the main body 41 of the positive electrode current collecting terminal 40.
In the main body 41 of the positive electrode current collecting terminal 40, the thickness of the part where the notch 43 and the connection part 44 are formed is thinner than the thickness of the other part of the main body 41.

  The notch 43 is a groove formed in the shape of a lower surface of the main body 41 of the positive current collector terminal 40 corresponding to the outer side of the recess 53a of the reversing plate 53 in a substantially circular shape in plan view. is there.

The connection portion 44 is a portion corresponding to the inner peripheral side of the portion where the cutout portion 43 is formed in the main body 41 of the positive electrode current collecting terminal 40. In the central portion of the connection portion 44, a hole portion having a substantially circular shape in plan view that fits through the main body 41 along the vertical direction is formed. The connecting portion 44 is joined to the recess 53a of the reversing plate 53 by welding.
That is, the positive electrode current collecting terminal 40 is electrically connected to the reversing plate 53 by contact between the connecting portion 44 and the recess 53 a of the reversing plate 53.

  In addition, joining of the connection part 44 and the recessed part 53a of the inversion board 53 is not what is welded without a gap over the perimeter, but is made into the grade which is welded at least one place.

  Next, the operation of the current cutoff valve 50 will be described with reference to FIGS. 1 and 3.

  When the battery 1 is overcharged, the components in the electrolytic solution are decomposed, and gas is generated inside the exterior 10. Along with this, the pressure outside the reversing plate 53 (internal pressure inside the exterior 10) increases, so that a pressure difference occurs between the inside (inside the through hole 51c) and the outside of the reversing plate 53.

If the pressure outside the reversing plate 53 exceeds a predetermined level, the current cutoff valve 50 deforms the reversing plate 53 to warp upward due to the pressure difference between the inside and the outside of the reversing plate 53. Along with this, the positive electrode current collecting terminal 40 is broken at the notch 43.
Thus, the current cutoff valve 50 detects overcharge, disconnects the connection portion 44 of the positive current collector terminal 40 from the main body 41, and interrupts the electrical connection between the reversing plate 53 and the positive current collector terminal 40.

  The leak check method for the current cutoff valve is to inspect the sealed state between the rivet 51 and the reverse plate 53 in order to ensure the operation of the current cutoff valve 50. In other words, the leak check method for the current cutoff valve performs a leak test on one end side of the through hole 51c (that is, the welded portion 53b between the rivet 51 and the reversing plate 53 located below the through hole 51c).

  Next, the procedure of leak inspection by the leak check method for the current cutoff valve will be described.

First, as shown in FIG. 4, in the leakage check method for a current cutoff valve, a current cutoff valve 50 is attached to the sealing plate 12. That is, in the leakage check method for the current cutoff valve, the external terminal 16, the insulating member 18, the sealing body 12, and the upper insulating member 52 are integrally fixed by the rivet 51.
In the leakage check method for the current cutoff valve, the outer peripheral edge of the reversing plate 53 is joined to the large diameter portion 51b of the rivet 51 by welding (see the welded portion 53b shown in FIG. 4).

  After the current cutoff valve 50 is attached to the sealing plate 12, in the current cutoff valve leak inspection method, the wound electrode body 20 (see FIG. 1) is not housed and the electrolyte is injected. The sealing plate 12 is set in a battery case (hereinafter referred to as “measurement case 100”) in a state where there is no battery.

  After the sealing plate 12 is set, as shown in FIG. 5, in the leak check method for the current cutoff valve, the fixing member 110 is inserted from the upper side (the other end side) of the through-hole 51 c of the rivet 51. The lower end is brought into contact with the recess 53 a of the reversing plate 53.

  The fixing member 110 is a substantially columnar member set to an outer diameter smaller than the inner diameter of the through hole 51c of the rivet 51. When the fixing member 110 is inserted into the through hole 51 c of the rivet 51, the upper end portion protrudes upward from the rivet 51.

After the fixing member 110 is inserted, as shown in FIG. 6, in the leak check method for the current cutoff valve, the upper side (the other end side) of the through hole 51c is covered with the sealing material 120, and the sealing material 120 and the reversing plate 53 are covered. The space in the through hole 51c closed by the step S is formed as a sealed space S.
In the leakage check method for the current cutoff valve, the sealed space S is subjected to vacuum processing (see the arrow shown in FIG. 6).

  At this time, in the leak check method for the current cutoff valve, for example, the sealed space S is formed and the vacuum treatment is performed on the sealed space S using the sealing material 120 and the nozzle 130 as shown in FIG.

  The sealing material 120 is formed using a resin as a material, and is formed in a recessed shape that is recessed upward. A hole through which the nozzle 130 can be inserted is formed on the upper side of the sealing material 120.

  The nozzle 130 is inserted into the hole of the sealing material 120 and is sealed with the sealing material 120. The nozzle 130 communicates with a decompression pump via a pipe or the like.

In the leak check method for the current cutoff valve, the lower end portion of the sealing material 120 is brought into contact with the upper surface of the small-diameter portion 51a of the rivet 51 so as to cover the upper side (the other end side) of the through hole 51c to form the sealed space S. .
At this time, in the leak check method for the current cutoff valve, the bottom surface of the sealing material 120 (the inner surface of the recessed portion) is brought into contact with the upper end portion of the fixing member 110.

  And in the leak check method of the current cutoff valve, the vacuum process is performed on the sealed space S by operating the pressure reducing pump and discharging the air in the sealed space S (see the arrow shown in FIG. 6).

Here, when vacuum processing is performed on the sealed space S as in this embodiment, the pressure outside the reversing plate 53 is compared with the pressure inside the reversing plate 53 (that is, the sealed space S side). Relatively high.
That is, as in the case where the battery 1 is overcharged, the pressure outside the reversing plate 53 is higher than the pressure inside the reversing plate 53. Further, since the sealed space S is evacuated, the pressure difference between the inside and outside of the reversing plate 53 becomes larger than when the pressure outside the reversing plate 53 exceeds a predetermined level.

  Therefore, when the vacuum processing is performed on the sealed space S as in the present embodiment, the reversing plate 53 tends to deform so as to warp upward.

Therefore, in the leak check method for the current cutoff valve, the fixing member 110 is inserted from the through hole 51c before the vacuum processing is performed, and the bottom surface of the sealing material 120 is brought into contact with the upper end portion of the fixing member 110, thereby fixing the fixing member 110. The reversing plate 53 is fixed by this.
According to this, in the leak check method for the current cutoff valve, the reversal plate 53 can be prevented from being deformed during the leak check.

  Thus, the fixing member 110 of this embodiment functions as a fixing member that fixes the reversal plate according to the present invention.

After performing vacuum processing on the sealed space S, as shown in FIG. 7, in the leak check method of the current cutoff valve, gas is injected into the measurement case 100 (see arrow H shown in FIG. 7).
In the leak check method for the current cutoff valve of the present embodiment, a nozzle connected to a predetermined helium supply source is inserted into the electrolyte solution injection hole formed in the sealing plate 12, and helium H is injected from the nozzle.
At this time, in the leakage check method for the current cutoff valve, the sealing space 120 is continuously covered with the sealing material 120 to maintain the sealed space S. Moreover, the measurement case 100 is sealed by a sealing plate 12 set on the opening surface so that at least the gas injected into the measurement case 100 does not leak outside.

After injecting helium H into the measurement case 100, the leak check method for the current cutoff valve detects helium H flowing into the sealed space S.
At this time, in the leakage check method for the current cutoff valve, for example, the amount of helium H flowing into the sealed space S is detected using a commercially available helium leak checker.
In the leakage check method for the current cutoff valve, it is determined based on the detected amount of helium H whether or not there is a leak in the weld 53b.

  As described above, the leak check method for the current cutoff valve performs a leak check on the lower side (one end side, that is, the welded portion 53b) of the through hole 51c by performing vacuum processing on the sealed space S.

  In the leak check method for the current cutoff valve according to the present embodiment, since the vacuum processing is performed on the sealed space S, it is compared with the case where the vacuum processing is performed on the space in the chamber large enough to contain the sealing body 12. Thus, the volume of the space to be evacuated can be reduced (see FIGS. 6 and 7).

According to this, the leak check method for the current cutoff valve can reduce the time for performing the vacuum processing, so that the leak check for the current cutoff valve 50 (below the through hole 51c) can be performed in a short time.
Therefore, the leak check method for the current cutoff valve can reduce the number of installed equipment for performing the leak check of the current cutoff valve 50 and can reduce the production cost of the battery 1.

In addition, as described above, the leak check method for the current cutoff valve is the deformation of the reversing plate 53 caused by the pressure difference between the inside and the outside of the reversing plate 53 when the sealed space S is subjected to vacuum processing. This can be prevented by the fixing member 110.
Accordingly, the leak check method for the current cutoff valve is such that the reverse plate 53 is not deformed even when the leak check of the current cutoff valve 50 is performed after the main body 41 of the positive current collector terminal 40 is joined to the recess 53a of the reverse plate 53. In other words, the leak inspection can be performed in a short time without the positive electrode current collecting terminal 40 being broken at the notch 43.

  The fixing member 110 only needs to have a shape that can fix the reversal plate 53 at the time of leak inspection, and is not necessarily a substantially columnar member.

  In the present embodiment, helium H is injected into the measurement case 100. However, the present invention is not limited to this. For example, hydrogen may be injected.

  The configuration of the current cutoff valve 50 is not limited to the present embodiment. For example, the current cutoff valve may have a configuration in which a through hole is formed in the positive terminal and the outer peripheral edge of the reversing plate is welded to a conductive member fixed to the positive terminal.

DESCRIPTION OF SYMBOLS 1 Battery 10 Exterior 50 Current cutoff valve 51c Through-hole 53 Inversion board 53b Welding part (one end side of a through-hole)
110 Fixing member S Sealed space

Claims (1)

A current cut-off valve for performing a leak test on one end side of the through-hole of a current cut-off valve in which a through-hole communicating with the inside and outside of the battery exterior is formed and a reversing plate is attached to one end side of the through-hole The leak inspection method of
Inserting a fixing member for fixing the reversing plate from the other end side of the through hole, and forming a sealed space covering the other end side of the through hole,
By performing a vacuum treatment on the sealed space, a leak inspection is performed on one end side of the through hole.
Current check valve leak inspection method.

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