JP2015141757A - Method for manufacturing power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a power storage device which is arranged so that whether the sealing of a liquid inlet with a seal cap is adequately performed or not can be checked even after regular sealing.SOLUTION: A method for manufacturing a secondary battery comprises the steps of: inserting an electrode assembly in a case main body 13 and then, welding a lid 14 to the case main body 13; injecting an electrolytic solution into a case 11 through a liquid inlet 14a formed in the lid 14; tentatively sealing the liquid inlet 14a with a seal cap after injecting the electrolytic solution; aging the secondary battery by charging and discharging the secondary battery and generating gas in the case 11 after the tentative sealing; removing the seal cap used for the tentative sealing from the liquid inlet 14a; regularly sealing the inlet with a seal cap 19 after the aging; and sticking a piece of tape 31 to the case 11 to cover the seal cap 19 after the regular sealing. The piece of tape 31 is arranged so that an adhesive layer 33, a discoloration layer 34, an insulative layer 35 and a resin layer 36 are disposed in turn from a face in contact with the case 11 outwardly of the case 11.

Description

  The present invention relates to a method for manufacturing a power storage device in which an electrode assembly and an electrolytic solution are housed in a case having a liquid injection hole.

  As described in Patent Document 1, for example, a secondary battery accommodates a battery element such as an electrode assembly in a case and closes an opening of the case with a lid. The case of the secondary battery is provided with a liquid injection hole for injecting the electrolyte into the case after the closure, and the liquid injection hole is sealed with a sealing plug after the injection of the electrolyte. Yes.

JP 2000-90914 A

  By the way, when the secondary battery is charged / discharged, gas is generated in the case as the electrolytic solution is decomposed. At this time, if the liquid injection hole is not sufficiently sealed by the sealing plug, gas is ejected from the liquid injection hole to the outside of the case. For this reason, it is necessary to confirm whether or not the liquid injection hole is sufficiently sealed with the sealing plug. However, after the liquid injection hole is fully sealed with a sealing plug such as a bolt or a blind rivet, the case is poured. It was difficult to confirm whether the liquid hole was sufficiently sealed.

  The objective of this invention is providing the manufacturing method of the electrical storage apparatus which can confirm whether the injection hole is fully sealed by the sealing plug even after this sealing.

  A method of manufacturing a power storage device that solves the above problem is a method of manufacturing a power storage device in which an electrode assembly and an electrolytic solution are housed in a case having a liquid injection hole, and the electrolytic solution is introduced into the case from the liquid injection hole. After the injection, charging and discharging is performed in a state where the liquid injection hole is temporarily sealed with a sealing plug, and after removing the sealing plug from the liquid injection hole and releasing gas from the case, the sealing plug is used. Adhering the adhesive layer and the electrolytic solution from the surface in contact with the case toward the outside of the case so as to cover the sealing plug after the sealing of the liquid injection hole and the sealing of the liquid injection hole The gist is to affix a tape configured to be a discoloration layer that changes color due to the above and a protective layer that prevents the electrolytic solution from penetrating to the discoloration layer to the case.

  When charge and discharge of the power storage device is performed in the manufacturing process after performing the main sealing, gas is generated in the case. At this time, if the liquid injection hole is not sufficiently sealed by the sealing plug, gas is ejected from the liquid injection hole to the outside of the case. The liquid ejected from the liquid injection hole is, for example, an organic solvent in which the electrolytic solution is vaporized, and when this solvent adheres to the tape, the color change layer of the tape changes color. For this reason, by confirming the discoloration of the tape, it is possible to determine whether or not the liquid injection hole is sufficiently sealed even after the main injection hole sealing.

Regarding the method for manufacturing the power storage device, it is preferable to remove the tape after performing a performance test of the power storage device.
According to this, since the tape loses its adhesiveness after shipment of the power storage device or the like, the tape does not fall off, and the tape can be prevented from becoming a foreign object.

In the method for manufacturing the power storage device, it is preferable that the tape is attached to a connection terminal that passes through the case and protrudes from the inside of the case.
According to this, not only the sealing state of the liquid injection hole and the sealing plug, but also the sealing state of the connection terminal and the case can be confirmed.

  According to the present invention, it can be confirmed whether or not the liquid injection hole is sufficiently sealed by the sealing plug even after the main sealing.

The perspective view which shows a secondary battery. (A) And (b) is a figure for demonstrating the manufacturing process of a secondary battery, (c) is a partially broken sectional view which expands and shows a tape. The enlarged view which shows the discolored tape. The enlarged view which shows the state which peels off a tape from a case.

Hereinafter, an embodiment of a method for manufacturing a power storage device will be described.
As shown in FIG. 1, a secondary battery 10 as a power storage device includes a case 11 that constitutes an exterior thereof, and an electrode assembly 12 is accommodated in the case 11. The case 11 also contains an electrolyte solution together with the electrode assembly 12. The case 11 includes a bottomed cylindrical case body 13 and a plate-like lid body 14 that closes an opening into which the electrode assembly 12 of the case body 13 is inserted. Both the case main body 13 and the lid body 14 are made of metal (for example, made of stainless steel or aluminum).

  The electrode assembly 12 includes a positive electrode, a negative electrode, and a separator that insulates the positive electrode from the negative electrode. The positive electrode is configured by applying a positive electrode active material to both surfaces of a positive metal foil (aluminum foil). The negative electrode is configured by applying a negative electrode active material to both surfaces of a negative electrode metal foil (copper foil). The electrode assembly 12 has a stacked structure in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked and a separator is interposed between the electrodes. Further, the electrode assembly 12 is electrically connected with a positive terminal 15 and a negative terminal 16 as connection terminals. A part of each of the positive electrode terminal 15 and the negative electrode terminal 16 passes through an insertion hole (not shown) provided in the lid body 14 and protrudes from the inside of the case 11 to the outside. Further, the positive electrode terminal 15 and the negative electrode terminal 16 protrude from an insulating ring 18 provided on the lid body 14.

  The lid 14 of the case 11 is provided with a liquid injection hole 14a for injecting an electrolytic solution into the case 11 (case main body 13). The liquid injection hole 14 a is closed by a sealing plug 19. For example, a bolt or a blind rivet is used as the sealing plug 19. When a bolt is used as the sealing plug 19, the bolt is screwed into a female screw formed on the inner peripheral surface of the liquid injection hole 14a or a nut provided inside the case 11, so that the liquid injection hole 14a Is sealed. When a blind rivet is used as the sealing plug 19, the liquid injection hole 14 a is sealed by forming a caulking portion in a portion protruding into the case 11 after the blind rivet is inserted into the liquid injection hole 14 a.

  Further, the lid 14 of the case 11 is cleaved when the pressure in the case 11 reaches an opening pressure, which is a predetermined pressure, so that the pressure in the case 11 does not increase excessively. Is provided outside the case 11. The release pressure of the pressure release valve 20 is set to a pressure at which the case 11 itself and the joint between the case body 13 and the lid body 14 can be broken before cracks or breakage can occur. The pressure release valve 20 has a valve body 21 that is thinner than the thickness of the lid body 14. The valve body 21 is located at the bottom of the concave portion 22 provided in the lid body 14 and is formed integrally with the lid body 14.

Next, a method for manufacturing the secondary battery 10 will be described.
First, the electrode assembly 12 is accommodated in the case body 13. After the electrode assembly 12 is accommodated, the lid 14 is provided so as to close the opening of the case body 13. At this time, the positive electrode terminal 15 and the negative electrode terminal 16 are inserted through the insulating ring 18. And the case 11 is comprised by welding the cover body 14 to the case main body 13. FIG.

  Next, as shown in FIG. 2A, an electrolytic solution is injected into the case 11 from a liquid injection hole 14 a formed in the lid body 14. And after inject | pouring electrolyte solution, the injection hole 14a is temporarily sealed with the sealing stopper. In the manufacturing process of the secondary battery 10, temporary sealing is performed on the assumption that the sealing plug is removed from the liquid injection hole 14a, and main sealing is performed on the assumption that the sealing plug is not removed from the liquid injection hole 14a. . Temporary sealing uses a temporary sealing plug that is easier to remove than the sealing plug used for the main sealing, or the same sealing plug as the main sealing plug used for the main sealing is easier than the main sealing. Removal is facilitated by providing it so that it can be removed. After temporary sealing, charging and discharging are repeatedly performed in order to suppress decomposition of the electrolytic solution by forming an insulating film on the active material of the electrode assembly 12. Then, gas is generated by the reaction between the electrolytic solution and each active material in the electrode assembly 12.

  Then, the secondary battery 10 is left in a predetermined temperature environment and aging is performed for self-discharge. After the aging is finished, the sealing plug used for temporary sealing is removed from the liquid injection hole 14 a and the gas in the case 11 is discharged out of the case 11. Then, the liquid injection hole 14 a is sealed by the sealing plug 19 to perform the main sealing of the liquid injection hole 14 a.

  As shown in FIG. 2B, after the main sealing of the liquid injection hole 14 a is performed, a polypropylene tape 31 is attached to the case 11 so as to cover the sealing plug 19. Further, the tape 31 is attached so as to cover the pressure release valve 20 in addition to the sealing plug 19. Similarly, a tape 32 is attached to the case 11 so as to cover the positive terminal 15 and the negative terminal 16. The tape 32 is the same tape as the tape 31.

  As shown in FIG.2 (c), the tapes 31 and 32 have the adhesion layer 33 which consists of an adhesive agent. Further, the tapes 31 and 32 have a color changing layer 34 laminated on the adhesive layer 33. The discoloration layer 34 is a paint for the tapes 31 and 32. The tapes 31 and 32 have an insulating layer 35 laminated on the color changing layer 34. The insulating layer 35 is made of a material that does not allow electrolyte solution to permeate. The tapes 31 and 32 are laminated on the insulating layer 35 and have a resin layer 36 made of polypropylene. The tapes 31 and 32 have the adhesive layer 33 attached to the case 11 so that the adhesive layer 33, the color changing layer 34, the insulating layer 35, and the resin are formed from the surface in contact with the case 11 toward the outside of the case 11. The layers 36 are stacked in this order. In the present embodiment, a protective layer is constituted by the insulating layer 35 and the resin layer 36.

  After the sealing of the liquid injection hole 14a, gas is generated in the secondary battery 10 due to performance inspections such as charging of the secondary battery 10, impedance measurement, and measurement of electrical characteristics. When the liquid injection hole 14a is not sufficiently sealed by the sealing plug 19 and the airtightness of the liquid injection hole 14a is not ensured, gas is ejected from the liquid injection hole 14a to the outside of the case 11. Similarly, when a crack or the like is generated in the valve body 21 or when the sealing between the positive electrode terminal 15 and the negative electrode terminal 16 and the insulating ring 18 is not sufficient, the crack generated in the valve body 21, Gas is ejected from between the positive electrode terminal 15 and the negative electrode terminal 16 and the insulating ring 18. This gas is mainly an organic solvent in which the electrolytic solution is vaporized.

  As shown in FIG. 3, the gas ejected from the secondary battery 10 adheres to the sealing plug 19, the tape 31 covering the pressure release valve 20, and the tape 32 covering the connection terminal. Then, the color change layer 34 of the tapes 31 and 32 changes color due to a chemical reaction with the organic solvent. For this reason, the sealing state of case 11 can be confirmed by confirming the color of tapes 31 and 32.

As shown in FIG. 4, after the performance test, the tape 31 is peeled off from the sealing plug 19 and the pressure release valve 20, and similarly, the tape 32 is peeled off from the positive electrode terminal 15 and the negative electrode terminal 16.
Next, the effect | action of the manufacturing method of the electrical storage apparatus of this embodiment is demonstrated.

  Since the tapes 31 and 32 are provided so as to cover the sealing plug 19, the pressure release valve 20 and the connection terminal after the main sealing, when gas is ejected from the secondary battery 10 after the main sealing, the tape 31, It can be confirmed that the 32 color-changing layers 34 are discolored and the sealing is not sufficient.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) After the case 11 is completely sealed, a tape 31 is attached so as to cover the sealing plug 19. For this reason, in the manufacturing process after the main sealing, gas is generated in the case 11, and when this gas is ejected from the liquid injection hole 14a, the discoloration layer 34 of the tape 31 is discolored. Therefore, if the injection hole 14a is not sufficiently sealed by the sealing plug 19, the discoloration layer 34 of the tape 31 is discolored, and if the injection hole 14a is sufficiently sealed, the discoloration of the tape 31 is performed. Since the layer 34 does not change color, it is possible to confirm whether or not the liquid injection hole 14a is sufficiently sealed by checking the color of the tape 31 after the performance test of the secondary battery 10 (before shipment) or the like.

  (2) The tapes 31 and 32 are laminated so as to become the adhesive layer 33, the color changing layer 34, and the insulating layer 35 from the surface in contact with the case 11. Therefore, when the gas is ejected from the inside of the case 11, the discoloration layer 34 is discolored. can do. For this reason, discoloration of the discoloration layer 34 due to a factor from the outside of the case 11 can be suppressed, and it can be appropriately confirmed whether or not the liquid injection hole 14a is sufficiently sealed.

  (3) After the performance test of the secondary battery 10, the tapes 31 and 32 are peeled off. After the secondary battery 10 is shipped, the tapes 31 and 32 lose their adhesiveness due to the aging of the tapes 31 and 32, and the tapes 31 and 32 do not fall off, and the tapes 31 and 32 are prevented from becoming foreign matters. can do.

  (4) Since the tapes 31 and 32 are peeled off, the volume is reduced by the amount of the tapes 31 and 32 as compared with the secondary battery that is used with the tapes 31 and 32 attached. For this reason, the secondary battery 10 can be reduced in size by the tapes 31 and 32, or the secondary battery 10 can be enlarged by the tapes 31 and 32 to increase the battery capacity.

(5) Moreover, by using the tapes 31 and 32 made of polypropylene, it is possible to confirm whether or not the liquid injection hole 14a is sufficiently sealed using the tapes 31 and 32 having a simple configuration.
(6) In addition to the liquid injection hole 14a, tapes 31 and 32 are provided so as to cover the pressure release valve 20 and the connection terminal. Therefore, not only the sealing of the liquid injection hole 14a and the sealing plug 19, but also whether or not the sealing of the lid body 14 and the valve body 21 and the sealing of the insulating ring 18 and the connection terminal are sufficient is confirmed. be able to.

In addition, you may change embodiment as follows.
In the embodiment, the main sealing is performed after the aging is performed. However, the main sealing may be performed before the aging is performed. In this case, when the gas is generated by aging, charging of the secondary battery 10 performed after aging, or performance inspection (impedance measurement or electrical characteristic measurement) of the secondary battery 10, the injection hole 14a is sufficiently sealed. It can be confirmed whether or not.

  The tape 31 provided so as to cover the sealing plug 19 may not be peeled off. Even when the tape 31 covering the sealing plug 19 is still adhered, there is little possibility that it becomes an obstacle when the secondary battery 10 is used.

  The tape 31 may cover only the sealing plug 19. Moreover, the sealing plug 19 and the pressure release valve 20 may be covered, and the sealing plug 19 and the connection terminal may be covered. Therefore, the tape only needs to cover at least the sealing plug 19.

○ Aging may also serve as a performance test.
The power storage device may be applied not to the secondary battery 10 but to another power storage device such as an electric double layer capacitor.

The lid 14 may be bonded to the case body 13 with an adhesive or the like.
As for the tapes 31 and 32, the insulating layer 35 should just be provided in the outer side (far side from the case 11) rather than the adhesion layer 33, between the adhesion layer 33 and the discoloration layer 34, and the insulation layer 35 and the resin layer. 36 may be provided with another layer.

  The tapes 31 and 32 may be formed of a protective layer only by the resin layer 36. When the resin layer 36 is made of a porous resin, it is necessary to provide the insulating layer 35 in order to prevent the electrolytic solution that has passed through the resin layer 36 from penetrating to the discoloration layer 34. On the other hand, if the resin layer 36 can prevent the electrolyte solution from penetrating to the discoloration layer 34, it is not necessary to provide the insulating layer 35 separately from the resin layer 36, and the resin layer 36 serves as a protective layer to suppress the electrolyte solution penetration. To do.

  The tapes 31 and 32 may be polyethylene terephthalate tapes. That is, a tape in which the resin layer 36 is made of polyethylene terephthalate may be used.

  DESCRIPTION OF SYMBOLS 10 ... Secondary battery, 11 ... Case, 12 ... Electrode assembly, 14a ... Injection hole, 15 ... Positive electrode terminal, 16 ... Negative electrode terminal, 31, 32 ... Tape, 33 ... Adhesive layer, 34 ... Discoloration layer, 35 ... Insulating layer, 36... Resin layer.

Claims (3)

A method of manufacturing a power storage device in which an electrode assembly and an electrolytic solution are housed in a case having a liquid injection hole,
After injecting the electrolyte from the liquid injection hole into the case, charging and discharging is performed in a state where the liquid injection hole is temporarily sealed with a sealing plug,
After removing the sealing plug from the liquid injection hole and releasing the gas from within the case, the liquid injection hole is fully sealed by the sealing plug,
An adhesive layer, a discoloration layer that changes color due to adhesion of the electrolytic solution, and an electrolytic solution so as to cover the sealing plug after the liquid injection hole is fully sealed from the surface in contact with the case toward the outside of the case A method of manufacturing a power storage device, comprising: attaching a tape configured to be a protective layer that suppresses permeation to the discolored layer to the case.   The method for manufacturing a power storage device according to claim 1, wherein the tape is removed after performing a performance test of the power storage device.   3. The method of manufacturing a power storage device according to claim 1, wherein the tape is attached to a connection terminal that passes through the case and protrudes from the inside of the case to the outside.