JP2015099670A - Sealed battery and gas-exhaust method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a sealed battery arranged so that gas can be easily exhausted to the outside even with the gas remaining in a case member; and a gas-exhaust method for such a sealed battery.SOLUTION: A sealed battery comprises: a power-generating element; a battery case provided with a liquid-pouring spout 17 for pouring an electrolyte, in which the power-generating element is enclosed; and a sealing member for sealing the liquid-pouring spout 17. The sealing member is composed of a blind rivet 18 which includes: a sleeve 20 including a flange part 22 larger than the liquid-pouring spout 17 in diameter and a sleeve main part 21 placed in the battery case; and a remaining member 28 remaining inside the sleeve 20. The remaining member 28 has a structure in which a protrusion part 32 protrudes toward a bottom part 29 of the sleeve 20.

Description

  The present invention relates to a sealed battery and a gas discharge method for the sealed battery.

As a conventional sealed battery, for example, a sealed battery disclosed in Patent Document 1 can be cited.
The sealed battery disclosed in Patent Document 1 includes an outer can and a sealing plate that seals the upper opening of the outer can.
The sealing plate is provided with two electrode terminals, a gas exhaust valve, and an electrolyte injection hole.
A sealing plug and a resin washer as a sealing member made of a blind rivet are attached to the electrolyte solution injection hole.
Moreover, the annular convex part which protrudes in the can axial direction is formed in the peripheral part surface of the electrolyte solution injection hole of a sealing board so that the electrolyte solution injection hole may be surrounded.
The sealing plug has a shaft portion that is inserted into the electrolyte solution injection hole, a flange portion that covers the peripheral surface of the electrolyte solution injection hole, and a crimping portion, and is sealed by the flange portion and the crimping portion. Caulking is fixed to the board.

By the way, in a sealed battery such as a lithium ion secondary battery, when a battery internal pressure rises, a current interrupt device (CID: Current Interrupt Device) that cuts off a charging current, or when the battery internal pressure reaches a predetermined pressure, In some cases, a safety valve that releases the generated gas to the outside is incorporated.
In a sealed battery having a current interruption element and a safety valve, for example, when the electrolyte solvent is decomposed due to overcharging and the battery internal pressure rises, the current interruption element interrupts the charging current, and when the battery internal pressure reaches a predetermined pressure, the safety valve The valve is opened to release the gas in the battery case to the outside.

JP 2011-76865 A

However, in a sealed battery such as a lithium ion secondary battery, even if the charging current is interrupted by the current interrupting element, the gas remains in the battery case when the internal pressure of the battery is such that the safety valve does not open. .
In this case, for example, when the sealed battery in which the gas remains is discarded, it is desirable that the gas remaining in the battery case is discharged and the internal pressure is set to about atmospheric pressure before being decomposed.
On the other hand, the sealed battery disclosed in Patent Document 1 discloses that the injection hole is sealed with a blind rivet, and that gas is discharged by a safety valve (gas discharge valve) when the internal pressure of the battery case increases. However, there is no disclosure of means for discharging gas when the internal pressure of the battery is such that the safety valve does not open.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a sealed battery that can easily discharge gas to the outside even when the gas remains in the battery case. The object is to provide a gas discharge method for a sealed battery.

  In order to solve the above problems, the present invention provides a power generation element, a battery case that houses the power generation element and is provided with a liquid injection port for injecting an electrolyte, and a blind rivet that seals the liquid injection port. The blind rivet remains inside the sleeve, and a sleeve having a flange portion having a diameter larger than the diameter of the liquid inlet and a bottomed cylindrical sleeve body portion located in the battery case. A sealed battery comprising a residual member, wherein the residual member has a protrusion that protrudes toward the bottom of the sleeve.

  According to the present invention, by pressing the residual member inside the blind rivet toward the bottom of the sleeve, an opening can be formed at the bottom of the sleeve, and the gas remaining in the battery case can be passed through the opening at the bottom of the sleeve. Can be discharged to the outside.

Further, in the above sealed battery, the residual member may have a restricting portion for allowing the residual member to stay in the sleeve at least a part of the periphery of the protrusion as viewed from the bottom of the sleeve. Good.
In this case, even if the projecting portion forms an opening in the bottom portion of the sleeve, the remaining member remains in the sleeve by the restricting portion and does not fall off the sleeve.
Therefore, it is possible to prevent the remaining members from being mixed into the battery case.

The present invention also relates to a gas discharge method for a sealed battery in which the gas remaining inside the sealed battery is discharged to the outside, wherein the remaining member is pressed toward the bottom of the sleeve, and the protrusion An opening is formed in the bottom of the sleeve, and gas inside the battery case is discharged to the outside of the battery case through the opening.
According to the present invention, by pressing the residual member toward the bottom of the sleeve, the protrusion forms an opening in the bottom of the sleeve, and the gas inside the battery case can be easily discharged to the outside through the opening. .

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where gas remains in a battery case, the gas discharge | emission method of the sealed battery which can discharge | emit gas outside easily and a sealed battery can be provided.

1 is a perspective view of a sealed battery according to a first embodiment. It is a longitudinal cross-sectional view of the blind rivet in the liquid inlet of a sealed battery. It is explanatory drawing explaining the sealing process of the liquid injection port by a blind rivet. It is explanatory drawing explaining the gas discharge | emission method of the sealed battery which concerns on 1st Embodiment. It is a longitudinal cross-sectional view of the blind rivet which concerns on 2nd Embodiment, (a) is a longitudinal cross-sectional view of the blind rivet after sealing, (b) is a longitudinal cross-sectional view of the blind rivet in a sealing process. It is explanatory drawing explaining the gas discharge | emission method of the sealed battery which concerns on 2nd Embodiment.

(First embodiment)
Hereinafter, a sealed battery and a gas discharge method for the sealed battery according to the first embodiment will be described with reference to the drawings.
The sealed battery according to this embodiment is a vehicle-mounted secondary battery, for example, a lithium secondary battery or a nickel hydride secondary battery.

The sealed battery shown in FIG. 1 includes a battery case 11 that is generally flat and has a substantially rectangular parallelepiped shape.
The battery case 11 has a box-shaped case main body 12 and a lid 13 that seals an opening (not shown) of the case main body 12.

The lid 13 is fixed to the case body 12 by laser welding.
Both the case main body 12 and the lid 13 are made of a metal material (for example, aluminum).
A cylindrical positive electrode terminal 14 and a negative electrode terminal 15 protrude from the lid 13.
The positive terminal 14 and the negative terminal 15 are insulated from the battery case 11.
The lid 13 is provided with a safety valve 16 that opens when the pressure in the battery case 11 reaches a predetermined pressure, and discharges the gas in the battery case 11 to the outside.
The lid 13 is provided with a liquid injection port 17 for injecting an electrolytic solution.
The liquid injection port 17 is sealed with a blind rivet 18.
The blind rivet 18 seals the liquid injection port 17, thereby preventing leakage of the electrolytic solution in the battery case 11 from the liquid injection port 17.
Details of the blind rivet 18 will be described later.

As shown in FIG. 1, the case body 12 accommodates a flat, substantially rectangular parallelepiped electrode body 19.
The electrode body 19 as a power generation element has a sheet-like positive electrode (not shown) and a negative electrode (not shown), and a sheet-like separator (not shown) interposed between the positive electrode and the negative electrode. .
The separator is made of an insulating material that allows the electrolyte to flow.
In the electrode body 19, the positive electrode and the negative electrode are alternately laminated via a separator.
The electrode body 19 includes a positive electrode current collector (not shown) connected to the positive electrode terminal 14 and a negative electrode current collector (not shown) connected to the negative electrode terminal 15.
The electrode body 19 is accommodated in the battery case 11 in a state of being covered with an insulating bag (not shown) formed of an insulating material.
In this embodiment, although not shown, a current interrupting element (CID) is incorporated.
The battery case 11 is filled with an electrolytic solution. The electrolytic solution is filled through the liquid injection port 17 after the electrode body 19 is accommodated in the battery case 11.
The electrolytic solution is an electrolytic solution according to the type of secondary battery such as a lithium secondary battery or a nickel hydride secondary battery.

Next, the blind rivet 18 will be described.
As shown in FIG. 2, the blind rivet 18 includes a sleeve 20 that is inserted through the liquid injection port 17 and fixed to the lid 13 by caulking.
The sleeve 20 is formed of a plastic material that is plastically deformed (for example, aluminum), has a portion having a smaller diameter than the liquid injection port 17, and has a bottomed cylindrical sleeve body portion 21 located in the battery case 11, A flange portion 22 having a diameter larger than the diameter of the liquid port 17 is provided.
The sleeve body 21 is inserted through the liquid injection port 17, and a flange portion 22 is integrally formed at the end of the sleeve body 21.
The flange portion 22 is formed so as to cover the periphery of the liquid injection port 17 in the lid 13, and the axial thickness of the flange portion 22 is set so as to increase from the outer peripheral edge of the flange portion 22 toward the center. ing.
The sleeve body 21 is formed with a caulking portion 23 having a slightly larger diameter than the liquid injection port 17, and the sleeve body 21 is caulked with respect to the lid 13 by the flange portion 22 and the caulking portion 23. Is fixed.

In this embodiment, a washer-like seal member 24 is installed between the flange portion 22 and the lid body 13.
The sealing member 24 is for preventing leakage of the electrolytic solution in the battery case 11 from the injection port 17 and is formed of resin.

First, a process preceding the sealing process in the manufacturing process of the sealed battery according to the present embodiment will be described.
A positive electrode terminal 14, a negative electrode terminal 15, and a safety valve 16 are formed on the lid 13, and the positive electrode current collector of the electrode body 19 is connected to the positive electrode terminal 14 and the negative electrode current collector is connected to the negative electrode terminal 15.
Next, the electrode body 19 is inserted into the case body 12, the opening of the case body 12 is covered with the lid body 13 after the electrode body 19 is inserted, and the lid body 13 and the case body 12 are joined by laser welding.
Next, the electrolytic solution is injected and filled into the battery case 11 through the injection port 17.
The electrolytic solution is injected into the battery case 11 using an electrolytic solution injection device (not shown).

Next, the sealing process in the sealed battery of this embodiment will be described.
As shown in FIG. 3A, the seal member 24 is arranged on the lid body 13 so as to surround the liquid injection port 17 formed on the lid body 13.
After injecting the electrolyte into the battery case 11, a blind rivet 18 is inserted into the injection port 17 as shown in FIG.
When the blind rivet 18 is inserted, a mandrel 25 is provided inside the sleeve 20.
The mandrel 25 is formed of a metal material (for example, stainless steel) having a hardness higher than that of the sleeve 20.
The mandrel 25 includes a shaft portion 26 provided in the sleeve 20, and a columnar enlarged diameter portion 27 provided at the tip of the shaft portion 26 and having a larger outer diameter than the outer diameter of the shaft portion 26. .
The enlarged diameter portion 27 is a part that is separated from the mandrel 25 when the liquid injection port 17 is sealed, and remains inside the sleeve 20 as a residual member 28 as shown in FIG.
A space portion 30 is formed between the enlarged diameter portion 27 and the bottom portion 29 of the sleeve 20, and a conical projection portion 32 protruding toward the bottom portion 29 of the sleeve 20 is formed on the end surface 31 of the enlarged diameter portion 27. It is integrally formed.
The protruding portion 32 is for making a hole in the bottom portion 29 of the sleeve 20 in order to discharge the gas in the battery case 11 after the enlarged diameter portion 27 remains as the remaining member 28 after sealing the liquid injection port 17. is there.
The end surface 31 around the protrusion 32 in the enlarged diameter portion 27 causes the residual member 28 to remain in the sleeve 20 even if the protrusion 32 of the residual member 28 is perforated in the bottom 29 of the sleeve 20 for degassing. Therefore, it functions as a regulation part.

In the mandrel 25, a reduced diameter portion 33 having an outer peripheral diameter set smaller than the outer peripheral diameter of the shaft portion 26 is formed between the shaft portion 26 and the enlarged diameter portion 27.
The reduced diameter portion 33 is formed to cut the mandrel 25 so that the enlarged diameter portion 27 can be easily separated from the shaft portion 26.

After the blind rivet 18 is inserted into the liquid injection port 17, when the mandrel 25 is pulled out from the sleeve 20 while pressing the flange portion 22 of the sleeve 20 toward the lid body 13, the enlarged diameter portion 27 of the mandrel 25 is covered with the lid. Approach the body 13 side.
As shown in FIG.3 (c), when the enlarged diameter part 27 approaches the cover body 13 side, a part of sleeve main-body part 21 is diameter-expanded by the enlarged diameter part 27, and the crimping part 23 is formed, The sleeve 20 is swaged and fixed to the lid body 13 by the flange portion 22 and the swaged portion 23.
Then, the tensile stress due to the pulling of the mandrel 25 concentrates on the reduced diameter portion 33, and the mandrel 25 is cut between the shaft portion 26 and the enlarged diameter portion 27.
For this reason, the shaft portion 26 is pulled out from the sleeve 20, and the enlarged diameter portion 27 is separated from the shaft portion 26 and remains inside the sleeve 20 as a residual member 28.
In the present embodiment, the blind rivet 18 seals the liquid injection port 17 through a sealing process.

Next, a method for discharging the gas in the battery case 11 will be described.
For example, when the electrolyte component of the electrode body 19 is decomposed due to overcharge and the internal pressure of the battery increases, the current interrupting element (CID) is activated to interrupt the charging current.
At this time, when the gas is generated in the battery case 11 and the battery internal pressure is such that the safety valve 16 does not operate, the gas remains in the battery case 11 and the pressure is higher than the atmospheric pressure.
Therefore, as shown in FIG. 4A, the operator inserts the pressing rod 35 into the sleeve 10 of the blind rivet 18, and directs the residual member 28 toward the bottom 29 of the sleeve 20 via the pressing rod 35. Press.
It is preferable that the pressing force is gradually increased so that the residual member 28 is not shocked when the residual member 28 is pressed by the pressing rod 35.

As shown in FIG. 4 (b), the residual member 28 is moved toward the bottom 29 of the sleeve 20 by the pressing of the residual member 28 by the pressing rod 35, and the protrusion 32 pierces the bottom 29 of the sleeve 20. An opening 36 is formed.
An opening 36 is formed in the bottom portion 29 of the sleeve 20, and the end surface 31 of the residual member 28 comes into contact with the inner surface of the bottom portion 29 by pressing of the pressing rod 35, so that the residual member 28 remains in the sleeve 20.
As shown in FIG. 4C, the operator pulls out the pressing rod 35 from the sleeve 20 after the opening 36 is formed in the bottom 29 of the sleeve 20.
The gas remaining in the battery case 11 is discharged to the outside of the battery case 11 through the opening 36 formed in the bottom 29 of the sleeve 20.
In FIG.4 (c), the flow of the gas discharged | emitted by a broken-line arrow is shown typically.
Although not shown, a gap is formed between the sleeve 20 and the residual member 28 so that gas can pass therethrough.
Further, the gas starts to be discharged when the opening 36 starts to be formed. However, the opening 36 is completely formed and the push rod 35 is extracted, so that the gas is more easily discharged to the outside.

According to this embodiment, there exist the following effects.
(1) By pressing the residual member 28 of the blind rivet 18 toward the bottom 29 of the sleeve 20 using the pressing rod 35, the opening 36 can be easily formed in the bottom 29 of the sleeve 20. For this reason, even when gas remains in the battery case 11, the gas remaining in the battery case 11 is easily and safely discharged to the outside of the battery case 11 through the opening 36 formed in the bottom portion 29 of the sleeve 20. can do.

(2) Even if the protrusion 32 of the residual member 28 forms the opening 36 at the bottom of the sleeve 20, the end surface 31 of the residual member 28 contacts the inner surface of the bottom 29, and the residual member 28 remains in the sleeve 20. No drop off from 20. Accordingly, it is possible to prevent the residual member 28 from being mixed into the battery case 11, and to reduce the trouble of removing the residual member 28 from the inside of the battery case 11.

(3) Since the pressing force is gradually increased when the residual member 28 is pressed by the pressing rod 35, the opening 36 can be gradually formed in the bottom 29 of the sleeve 20, and the remaining gas is gradually released. Can do.

(Second Embodiment)
Next, a second embodiment will be described.
The present embodiment is an example in which the shape of the remaining member in the blind rivet is different from that of the first embodiment.
Since it is the same as that of a 1st embodiment about composition other than a residual member, explanation of a 1st embodiment is used and a common code is used.

As shown in FIG. 5A, the blind rivet 18 in the sealed battery according to the present embodiment has a remaining member 41 remaining in the sleeve 20.
As shown in FIG. 5B, the remaining member 41 is a member that remains on the sleeve 20 after the diameter-increasing portion 42 of the mandrel 25 is separated from the shaft portion 26 by cutting after the liquid injection port 17 is sealed.
A conical projection 43 projecting toward the bottom 29 of the sleeve 20 is integrally formed with the enlarged diameter portion 42.
Since the protrusion 43 of the present embodiment is reduced in diameter from the outer periphery of the enlarged diameter portion 42 toward the center on the bottom 29 side, the residual member 41 does not include the end face 31 of the first embodiment.

In the present embodiment, as in the first embodiment, the operator discharges the gas in the battery case 11 using the pressing rod 35.
As shown in FIG. 6A, when the residual member 41 is pressed by the pressing rod 35, the residual member 41 moves toward the bottom 29 of the sleeve 20, and the protrusion 43 opens the bottom 29 of the sleeve 20. An opening 44 is formed.
The opening 44 formed in the bottom 29 of the sleeve 20 expands by continuing to press the residual member 41 by the pressing rod 35.
As shown in FIG. 6B, when the protrusion 43 penetrates the sleeve 20, the remaining member 41 falls off the sleeve 20 and enters the battery case 11.
After the residual member 41 falls off the sleeve 20, the pressing rod 35 is extracted.

The gas remaining in the battery case 11 is discharged to the outside of the battery case 11 through the opening 44 formed in the bottom 29 of the sleeve 20.
The gas starts to be discharged when the opening 44 starts to be formed. However, when the opening 44 is completely formed and the pressing rod 35 is extracted, the gas is more easily discharged to the outside.
In FIG. 6 (b), the flow of the gas discharged is schematically shown by broken-line arrows.

According to the present embodiment, even when gas remains in the battery case 11, the gas remaining in the battery case 11 can be easily discharged to the outside of the battery case 11 through the opening 44 formed in the bottom portion 29 of the sleeve 20. And can be discharged safely.
Further, since the pressing force is gradually increased when the residual member 41 is pressed by the pressing rod 35, the opening 44 can be gradually formed in the bottom 29 of the sleeve 20, and the remaining gas can be gradually released. it can.
Furthermore, since the projection 43 has a large opening 44 so that the residual member 41 falls off the sleeve 20, the gas in the battery case 11 can be discharged faster than in the first embodiment.

  The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the gist of the invention. For example, the following modifications may be made.

In the above embodiment, the operator presses the remaining member with the pressing rod, but this is not the case. The pressing of the remaining member by the pressing rod is not limited to the operator and may be equipment for operating the pressing rod.
In the above embodiment, the case where the electrolyte component is decomposed due to overcharging and the battery internal pressure increases and the current interrupting element (CID) operates is described. However, the generation of gas is not limited to the internal pressure increase due to overcharging. Even when gas is generated due to another cause, the gas may be discharged after the operation of the current interrupting element (CID). Furthermore, the bottom of the sleeve may be opened unconditionally when there is a possibility of gas generation regardless of whether or not the current interrupting element (CID) is activated.
In the above embodiment, the sealed battery including the current interrupting element (CID) has been described. However, the present invention can also be applied to a sealed battery not including the current interrupting element (CID).
In the first embodiment, the protrusion is conical, but the shape of the protrusion is not limited to the conical shape, and is not particularly limited as long as the opening can be formed at the bottom of the sleeve. Further, a plurality of protrusions may be formed on the remaining member.
In the above second embodiment, the residual member penetrates the sleeve by the pressing of the pressing rod and enters the inside of the battery case, but this is not restrictive. For example, the opening may be formed by pressing the remaining member so as not to completely penetrate the sleeve, and the remaining member may be retained in the sleeve. In this case, even if the remaining member is not provided with the restricting portion, the remaining member can be retained in the sleeve.

10, 40 Sealed battery 11 Battery case 12 Case body 13 Cover body 17 Injection port 18 Blind rivet 19 Electrode body 20 Sleeve 21 Sleeve body part 22 Flange part 23 Clamping part 24 Seal member 25 Mandrel 26 Shaft part 27, 42 Expansion Diameter portion 28, 41 Residual member 29 Bottom portion 31 End face (Regulator)
32, 43 Protrusion 35 Press rod 36, 44 Opening

Claims (3)

Power generation elements,
A battery case that houses the power generation element and is provided with a liquid injection port for injecting an electrolyte solution;
A blind rivet for sealing the liquid injection port,
The blind rivet is
A sleeve having a flange portion having a diameter larger than the diameter of the liquid injection port and a bottomed cylindrical sleeve body portion located in the battery case;
In a sealed battery comprising a remaining member remaining inside the sleeve,
The sealed battery according to claim 1, wherein the residual member has a protrusion that protrudes toward the bottom of the sleeve.   2. The hermetic mold according to claim 1, wherein the residual member has a restricting portion for allowing the residual member to stay in the sleeve at least at a part of the periphery of the protrusion when viewed from the bottom of the sleeve. battery. A gas discharge method for a sealed battery, wherein the gas remaining inside the sealed battery according to claim 1 or 2 is discharged to the outside.
Pressing the residual member toward the bottom of the sleeve, forming an opening in the bottom of the sleeve by the protrusion,
A gas discharge method for a sealed battery, wherein the gas inside the battery case is discharged to the outside of the battery case through the opening.

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