JP2007323882A - Sealed battery and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce defects of regular sealing executed after tentative sealing. <P>SOLUTION: After a power generation element is stored in an armoring can having a sealed structure, an electrolyte is injected from an electrolyte injection hole 11 formed in a sealing seat 12 of a sealing lid 5 of the armoring can, the electrolyte injection hole 11 is tentatively sealed, battery adjustment is carried out, and thereafter the electrolyte injection hole 11 is regularly sealed after canceling the tentative sealing. In this case, the tentative sealing is executed by sequentially sealing resin sheets 15 and 16 at respective sealing positions P1 and P2 around the electrolyte injection hole 11, and the regular sealing is executed by sealing a regular sealing lid 13 around the electrolyte injection hole 11 at a sealing position P3 on the outside of the positions P1 and P2 where the resin sheets 15 and 16 are sealed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sealed battery such as a lithium ion battery. Specifically, after injecting an electrolytic solution from a liquid injection hole into an outer container, the liquid injection hole is temporarily sealed, and after the battery is adjusted, the injection is performed. The present invention relates to a sealed battery in which liquid holes are finally sealed and a method for manufacturing the same.

  Conventionally, in order to manufacture a lithium ion battery, it is necessary to perform battery adjustment such as initial charge after housing a power generation element including an electrolytic solution in a sealed outer package at the final stage. Since this initial charging involves gas generation, if the initial charging is performed with the generated gas released, the electrolyte in the outer container may spill. In order to prevent this, it is necessary to perform the initial charging with the battery outer container sealed. After the initial charging, the generated gas must be released, and after the generated gas is released, the outer container needs to be sealed again. is there.

  Therefore, the manufacturing method described in Patent Document 1 below discloses a battery manufacturing method in which temporary sealing and main sealing are performed before and after initial charging. That is, this manufacturing method uses a rubber-elastic sealing plug having a normally closed structure that opens by being deformed by applying force from the outside. And after temporarily sealing an exterior container with this sealing stopper and performing initial charge in the temporarily sealed state, after performing the gas-liquid separation operation in an exterior container, the sealing container is operated and an exterior container is operated. The inner gas is discharged, and the normally closed valve structure of the sealing plug is closed to perform the main sealing of the outer container.

2001-338684 gazette No. 2000-353547 2004-172012 Publication

  However, in the manufacturing method described in Patent Document 1, since temporary sealing and main sealing are performed using the same sealing plug, a residue of temporary sealing becomes a factor that hinders main sealing, and main sealing. There was a risk of failure. If there is a main sealing failure, there is a concern that the sealing of the outer container cannot be secured throughout the warranty period of the battery. For example, before performing main sealing after gas release, it may be necessary to wipe off the electrolytic solution adhering to the sealing surface, but there was a risk of main sealing failure due to insufficient wiping. . Further, the state of the liquid injection port is changed by the temporary sealing, and the quality of the main sealing may be unstable.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a sealed battery that can reduce defects in main sealing performed after temporary sealing. Another object of the present invention is to provide a sealed battery capable of improving the main sealing quality by a multiple sealing structure.

  In order to achieve the above object, according to the first aspect of the present invention, after the power generating element is accommodated in the sealed outer container, the electrolytic solution is injected from the liquid injection hole of the outer container, and the liquid injection hole is temporarily sealed. After the battery is adjusted, the temporary sealing is released, and after a series of steps including temporary sealing, battery adjustment and temporary sealing release is performed at least once, the liquid injection hole is fully sealed. In the manufacturing method of a type battery, temporary sealing is performed by sealing a temporary sealing member around the liquid injection hole, and the main sealing is performed at a position different from the position where the temporary sealing member is sealed. The purpose is to seal the sealing member around the liquid injection hole.

  According to the configuration of the above invention, the temporary sealing member is sealed around the liquid injection hole to perform temporary sealing, and the liquid injection hole is at a position different from the position where the temporary sealing member is sealed. Since the main sealing is performed by sealing the main sealing member around the, the influence of temporary sealing on the sealing of the main sealing member is small.

  In order to achieve the above object, according to a second aspect of the present invention, in the first aspect of the invention, the position where the sealing member is sealed is outside the position where the temporary sealing member is sealed. The purpose is that.

  According to the structure of the said invention, in addition to the effect | action of the invention of Claim 1, this sealing member can be arrange | positioned on a temporary sealing member, and it is not necessary to remove a temporary sealing member.

  In order to achieve the above object, according to a third aspect of the present invention, in the first aspect of the present invention, the position where the sealing member is sealed is inside the position where the temporary sealing member is sealed. The purpose is that.

  According to the structure of the said invention, in addition to the effect of the invention of Claim 1, this sealing member will be sealed after removing a temporary sealing member, and it is not necessary to leave a temporary sealing member.

  In order to achieve the above object, a fourth aspect of the present invention provides a sealed outer container including a liquid injection hole, a power generation element accommodated in the outer container, and a seal formed by sealing the liquid injection hole. In the sealed battery including the stop member, the sealing member is used for temporarily sealing the liquid injection hole and sealed around the liquid injection hole, and the temporary sealing member includes It is intended to include a main sealing member that is sealed to fully seal the liquid injection hole at a position outside the sealed position.

  According to the configuration of the invention, the main sealing member is disposed on the temporary sealing member, and the main sealing member is sealed at a position outside the position where the temporary sealing member is sealed. Therefore, the temporary sealing member does not interfere with the sealing of the main sealing member. Further, the liquid injection hole is finally sealed by a multiple structure including a temporary sealing member and a main sealing member.

  According to invention of Claim 1, the sealing failure of the main sealing performed after temporary sealing can be reduced.

  According to the invention described in claim 2, in addition to the effect of the invention described in claim 1, the trouble of removing the temporary sealing member can be saved, and the efficiency of battery manufacturing can be improved.

  According to invention of Claim 3, in addition to the effect of invention of Claim 1, this sealing member can be reduced in size.

  According to invention of Claim 4, the quality of this sealing can be improved.

[First Embodiment]
Hereinafter, a sealed battery and a manufacturing method thereof according to a first embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a front view of a lithium ion battery (hereinafter simply referred to as “battery”) 1 as a sealed battery of the present invention. FIG. 2 shows the battery 1 in a plan view. The battery 1 includes an outer can 2, a power generation element 3 housed in the outer can 2, and an electrolyte injected into the outer can 2. The outer can 2 corresponds to the sealed outer container in the present invention, and includes a metal can body 4 having a flat box shape and a metal sealing lid 5 that seals the opening of the can body 4. A positive electrode terminal 7 and a negative electrode terminal 8 are attached to the sealing lid 5 via a gasket 6. The sealing lid 5 includes a safety valve 9 and a liquid injection part 10. The liquid injection part 10 includes a liquid injection hole 11 for injecting an electrolyte into the outer can 2. The liquid injection hole 11 also serves as a gas vent for extracting gas generated in the outer can 2.

  The safety valve 9 is for urgently opening and venting gas when the outer can 2 becomes excessive in internal pressure. The safety valve 9 is formed of a valve piece made of a thin metal plate and has a score line 9a at the center thereof. When the outer can 2 becomes excessive in internal pressure, the safety valve 9 is broken and opened at the scored line 9a, and the outer can 2 is degassed.

  In the final stage of manufacturing the battery 1 described above, it is necessary to charge the battery 1 in advance in order to commercialize the battery 1 into a charged state that can be used immediately. Since this initial charging involves the generation of gas, it is necessary to remove this generated gas before commercialization. Therefore, the liquid injection unit 10 injects the electrolyte from the liquid injection hole 11, temporarily seals the liquid injection hole 11, performs initial charging, and then releases the temporary sealing to degas the outer can 2. The liquid injection hole 11 is finally sealed.

  Here, the structure of the liquid injection unit 10 will be described with reference to FIGS. In FIG. 3, the liquid injection part 10 and its vicinity are expanded and shown with a top view. In FIG. 4, the liquid injection part 10 and its vicinity are expanded and shown with a front view. FIG. 5 is a sectional view taken along line AA in FIG. FIG. 6 is a cross-sectional view taken along line BB in FIG. FIG. 7 is an enlarged cross-sectional view of the broken line in FIG.

  As shown in FIGS. 3 and 4, the liquid injection part 10 includes a sealing seat 12 provided on the sealing lid 5 and a main sealing lid 13 as the main sealing member of the present invention. The sealing seat 12 and the main sealing lid 13 are each formed from a resin. As shown in FIGS. 5 to 7, the sealing seat 12 is integrally molded with the sealing lid 5 around the perforations 5 a provided in the sealing lid 5, and protrudes up and down with respect to the plate thickness of the sealing lid 5. Yes. A liquid injection hole 11 is formed in the sealing seat 12. On the upper surface of the sealing seat 12, a step portion 12 a protruding in a circle around the liquid injection hole 11 is formed, and the upper surface of the step portion 12 a is a flat sealing surface 14. On the sealing surface 14, two resin sheets 15 and 16 as temporary sealing members of the present invention for temporarily sealing the liquid injection hole 11 are arranged and sealed one above the other. The main sealing lid 13 is disposed by being fitted on the outer periphery of the stepped portion 12 a and is sealed to the upper surface of the sealing seat 12. Here, the two resin sheets 15 and 16 are formed to have a thickness that satisfies hermeticity (pressure resistance, leak resistance, moisture resistance permeation) necessary for temporary sealing and ease of degassing. This thickness is, for example, about “0.025 mm”. The upper second resin sheet 16 is formed to have a larger diameter than the lower first resin sheet 15. On the other hand, the main sealing lid 13 has a structure that satisfies hermeticity within the battery guarantee period necessary for main sealing. That is, the sealing lid 13 has a plate thickness of, for example, “0.7 mm” and has a cap shape. The state where the main sealing lid 13 is sealed to the sealing seat 12 means that the battery 1 is in a state of being commercialized after battery adjustment such as initial charging and degassing.

  Here, the final manufacturing method for commercializing the battery 1 described above will be described with reference to FIGS. This manufacturing method is performed after housing the power generation element 3 in the outer can 2.

  FIG. 8 is a flowchart showing a series of manufacturing steps before commercialization. 9-14 shows each process by a conceptual diagram. First, in step 1, an electrolytic solution is injected. That is, as shown in FIG. 9, the electrolytic solution is injected into the outer can 2 through the liquid injection hole 11 of the sealing seat 12.

  Next, in step 2, the sealing surface 14 is wiped off. That is, the sealing surface 14 is cleaned by wiping off the electrolyte or the like attached to the sealing surface 14.

  In step 3, the first temporary sealing is performed. That is, as shown in FIG. 10, the liquid injection hole 11 is temporarily sealed by placing and sealing the first resin sheet 15 on the sealing surface 14. In this embodiment, the first resin sheet 15 is sealed to the sealing surface 14 by laser welding at the first sealing position P1 surrounding the liquid injection hole 11.

  In step 4, the battery 1 is initially charged. Thereafter, in step 5, the first degassing is performed. That is, as shown in FIG. 11, the first resin sheet 15 is made with a vent 15a with a needle or the like, and the gas generated in the outer can 2 is released to the outside through the liquid injection hole 11 and the vent 15a.

  In step 6, second temporary sealing is performed. That is, as shown in FIG. 12, the second resin sheet 16 is stacked on the first resin sheet 15, and the resin sheet 16 is sealed to the sealing surface 14, thereby temporarily sealing the liquid injection hole 11. . Then, the second resin sheet 16 is sealed to the sealing surface 14 by laser welding at the second sealing position P2 that surrounds the liquid injection hole 11 outside the first sealing position P1.

  In step 7, the battery 1 is charged second. Thereafter, in step 8, the second degassing is performed. That is, as shown in FIG. 13, similarly to the first resin sheet 15, the second resin sheet 16 is also provided with a vent hole 16 a with a needle or the like, and the gas generated in the outer can 2 is passed through the injection hole 11 and the passage. It discharges outside through the pores 15a and 16a.

  In step 9, the main sealing is performed. That is, as shown in FIG. 14, the main sealing lid 13 is fitted and arranged on the outer periphery of the stepped portion 12a, and the main sealing lid 13 is sealed at the third sealing position P3 outside the stepped portion 12a. It seals on the upper surface of the seat 12 by laser welding. In this way, the battery 1 that has been commercialized is obtained by completing the battery adjustment including the first charging and the second charging, and the first degassing and the second degassing.

  According to the manufacturing method of the battery 1 in this embodiment described above, the first resin sheet 15 for the first temporary sealing is sealed at the first sealing position P1 on the sealing surface 14 around the liquid injection hole 11. To wear. Thereafter, the second resin sheet 16 for second temporary sealing is overlaid on the first resin sheet 15, and at the second sealing position P2 surrounding the liquid injection hole 11 outside the first sealing position P1, The second resin sheet 16 is sealed to the sealing surface 14. Then, the main sealing lid 13 for main sealing is sealed around the injection hole 11 at a third sealing position P3 different from the two sealing positions P1 and P2 for sealing the resin sheets 15 and 16. To wear. Therefore, the influence of the first temporary sealing and the second temporary sealing on the sealing of the main sealing lid 13 is small. For this reason, the sealing failure of the main sealing performed after 1st temporary sealing and 2nd temporary sealing can be reduced.

  In particular, in this embodiment, for the main sealing at the third sealing position P3 outside the first and second sealing positions P1, P2 for the first temporary sealing and the second temporary sealing. The sealing lid 13 is sealed around the liquid injection hole 11. Therefore, the influence of the first temporary sealing and the second temporary sealing on the sealing of the main sealing lid 13 is small. That is, since the main sealing lid 13 is disposed on the two resin sheets 15 and 16 so as to enclose the two resin sheets 15 and 16, the two resin sheets 15 and 16 are sealed. There is no need to remove the two resin sheets 15, 16 from the sealing seat 12, and there is no need to remove the residue after the peeling. In this sense, it is possible to reduce defects in the main sealing performed after the first temporary sealing and the second temporary sealing. In addition, since it is not necessary to remove the two resin sheets 15 and 16, it is possible to save the labor of manufacturing and to simplify the main sealing process. Further, the third sealing position P3 is outside the first and second sealing positions P2 and P2, and is appropriately separated from the liquid injection hole 11, so that the electrolytic solution is difficult to adhere. For this reason, the trouble of wiping the electrolyte solution from the sealing surface 14 before the main sealing can be saved, and in this sense, the main sealing process can be simplified and the main sealing failure can be reduced. .

  In addition, according to the battery 1 of this embodiment, the first sealing lid 13 is disposed so as to cover the two resin sheets 15 and 16, and the first resin sheet 15 and 16 are sealed. Since the main sealing lid 13 is sealed at the third sealing position P3 different from the second sealing positions P1 and P2, the two resin sheets 15 and 16 are sealed to the main sealing lid 13. Does not get in the way. Further, the liquid injection hole 11 is finally sealed by a multiple structure composed of two resin sheets 15 and 16 and a main sealing lid 13. That is, since the two resin sheets 15 and 16 remain inside the sealing lid 13, the air holes 15 a and 16 a are extremely small compared to the liquid injection hole 11, although they have the air holes 15 a and 16 a. Thus, the two resin sheets 15 and 16 exhibit the function of restricting the passage of the electrolytic solution in the outer can 2 and the function of assisting the main sealing by the main sealing lid 13. In this sense, a multiple sealing structure by the two resin sheets 15 and 16 and the main sealing lid 13 is obtained, and the battery 1 with improved main sealing quality can be obtained.

[Second Embodiment]
Next, a second embodiment that embodies the manufacturing method of the sealed battery of the present invention will be described in detail with reference to the drawings.

  In this embodiment, the configuration is different from the above-described embodiment in that the position where the main sealing member is sealed is inside the position where the temporary sealing member is sealed. Here, the final manufacturing method for commercializing the sealed battery of the present embodiment will be described with reference to FIGS. This manufacturing method is also performed after the power generation element is accommodated in the outer can as in the first embodiment.

  FIG. 15 is a flowchart showing a series of manufacturing steps before commercialization. 16 to 19 are conceptual diagrams showing each process. As shown in FIGS. 16 to 19, in this embodiment, a recess 23 is formed around the liquid injection hole 22 formed in the sealing seat 21 of the outer container.

  First, in step 1, an electrolytic solution is injected. That is, as shown in FIG. 16, the electrolytic solution is injected into the outer container through the liquid injection hole 22 of the sealing seat 21.

  Next, in step 2, the sealing surface 24 of the sealing seat 21 is wiped off. That is, the sealing surface 24 is cleaned by wiping off the electrolyte or the like attached to the sealing surface 24.

  In step 3, temporary sealing is performed. That is, as shown in FIG. 17, the liquid injection hole 22 is temporarily sealed by placing and sealing the resin temporary sealing member 25 on the sealing surface 24 of the sealing seat 21. In this embodiment, the temporary sealing member 25 is sealed to the sealing surface 24 by laser welding at the first sealing position P1 surrounding the liquid injection hole 22.

  In step 4, the battery is initially charged. Thereafter, in step 5, degassing is performed. That is, as shown in FIG. 18, the temporary sealing member 25 is peeled off to open the liquid injection hole 22, thereby releasing the gas generated in the outer container to the outside through the liquid injection hole 22.

  In step 6, the main sealing is performed. That is, as shown in FIG. 19, a metal main sealing member 26 is fitted and disposed in the recess 23, and at the second sealing position P <b> 2 on the bottom surface of the recess 23, the main sealing member 26 Is sealed to the bottom surface of the recess 23 by laser welding. In this way, battery adjustment including initial charging and degassing can be completed, and a sealed battery that has been commercialized can be obtained.

  According to the manufacturing method of this embodiment described above, the temporary sealing member 25 for temporary sealing is sealed at the first sealing position P1 of the sealing surface 24 around the liquid injection hole 22, and the position The main sealing member 26 is sealed around the liquid injection hole 22 at a second sealing position P2 different from P1. Therefore, the temporary sealing has little influence on the sealing of the main sealing member 26. For this reason, the sealing failure of the main sealing performed after temporary sealing can be reduced.

  In particular, in this embodiment, the temporary sealing member 25 for temporary sealing is sealed at the first sealing position P1 around the liquid injection hole 22, and the temporary sealing member 25 is peeled off. The main sealing member 26 is sealed at the second sealing position P2 in the recess 23 inside the first sealing position P1. For this reason, it is not necessary to leave the temporary sealing member 25, and the structure of the main sealing member 26 can be simplified. Further, since there is no need to worry about the residue after the temporary sealing member 25 is peeled off, the temporary sealing member 25 can be easily removed, and the manufacturing can be simplified correspondingly, and the productivity can be reduced. Can be improved. Furthermore, after the temporary sealing member 25 is peeled off, a certain amount of residue may remain, so that the temporary sealing can be performed using a relatively strong temporary sealing member. In this sense, the airtightness of the liquid injection hole 22 can be increased until the main sealing is performed, and in this sense, the quality of the battery can be improved.

  Further, according to the battery 1 of this embodiment, since the main sealing member 26 is fitted into the recess 23 around the liquid injection hole 22, the main sealing member 26 does not protrude to the outside, and the main sealing is completed. The subsequent appearance can be shown simply.

  The present invention is not limited to the above-described embodiments, and can be implemented as follows without departing from the spirit of the invention.

  (1) In the said 1st Embodiment, although the sealing seat 12 protrudes up and down to the plate | board thickness direction of the sealing lid 13, and is integrally resin-molded, as shown to FIGS. It is also possible to form a cylindrical portion 31a that protrudes into the cylindrical portion 31 and to fix the sealing seat 33 including the liquid injection hole 32 in the cylindrical portion 31a. Here, as shown in FIGS. 20 to 23, a recess 34 is formed in the sealing seat 33 around the liquid injection hole 32. 20 and 21, the first temporary sealing member 35 is sealed in the recess 34 to perform the first temporary sealing, and then the vent hole 35a is formed to release the temporary sealing. After the first degassing, the second temporary sealing member 36 is sealed on the upper surface of the sealing seat 33 to perform the second temporary sealing. Then, after venting 36a was formed, the temporary sealing was canceled and the second degassing was performed, as shown in FIGS. 22 and 23, the main sealing member 37 is placed on the upper end of the cylindrical portion 31a of the sealing lid 31. The main sealing may be performed by sealing. Also in this case, basically, the same effect as that of the first embodiment can be obtained.

  (2) In the first embodiment, the resin sheets 15 and 16 and the main sealing lid 13 are sealed to the sealing seat 12 by laser welding. However, as shown in FIG. , 36 may be made of resin, and may be sealed by thermal welding using a thermal mold 38 to the sealing seat 33. As shown in FIG. 21, each temporary sealing member 35, 36 is made of resin, The sealing seat 33 may be sealed by laser welding.

  (3) In the first embodiment, the resin main sealing lid 13 is sealed to the resin sealing seat 12 by laser welding. However, as shown in FIG. 22, a metal main sealing member is used. 37 may be sealed to the upper end of the metallic cylinder portion 31a by laser welding. Further, as shown in FIG. 23, the main sealing member 37 may be constituted by a metal safety valve, and the safety valve may be sealed to the upper end of the metal cylinder portion 31a by laser welding.

  (4) In the second embodiment, laser welding is employed for sealing the temporary sealing member 25, but heat welding or ultrasonic vibration welding using a thermal mold may be employed.

  (5) In the second embodiment, laser welding is employed for sealing the sealing member 26, but ultrasonic welding or resistance welding may be employed.

  (6) In the first embodiment, the resin sheets 15 and 16 are used as the temporary sealing member. However, as the temporary sealing member, a rubber plug or a screw or a spring presser may be used. .

The front view which shows a battery. The top view which shows a battery. The top view which expands and shows a liquid injection part and its vicinity. The front view which expanded the liquid injection part and its vicinity. AA line sectional view of Drawing 3. BB sectional drawing of FIG. Sectional drawing which expands and shows the inside of the broken line of FIG. The flowchart which shows a series of manufacturing processes. The conceptual diagram which shows each process. The conceptual diagram which shows each process. The conceptual diagram which shows each process. The conceptual diagram which shows each process. The conceptual diagram which shows each process. The conceptual diagram which shows each process. The flowchart which shows a series of manufacturing processes. The conceptual diagram which shows each process. The conceptual diagram which shows each process. The conceptual diagram which shows each process. The conceptual diagram which shows each process. Sectional drawing which shows another embodiment. Sectional drawing which shows another embodiment. Sectional drawing which shows another embodiment. Sectional drawing which shows another embodiment.

Explanation of symbols

1 Battery 2 Exterior can (exterior container)
3 Power generation element 4 Can body 5 Sealing lid 10 Liquid injection part 11 Liquid injection hole 12 Sealing seat 13 Main sealing lid (main sealing member)
14 sealing surface 15 1st resin sheet (temporary sealing member)
16 Second resin sheet (temporary sealing member)
21 Sealing seat 22 Injection hole 24 Sealing surface 25 Temporary sealing member 26 Main sealing member 31 Sealing lid 32 Injection hole 33 Sealing seat 35 First temporary sealing member 36 Second temporary sealing member 37 Main seal Stop member P1 First sealing position P2 Second sealing position P3 Third sealing position

Claims (4)

After housing the power generation element in a sealed outer container, the electrolyte is injected from the liquid injection hole of the outer container, the liquid injection hole is temporarily sealed, the battery is adjusted, and then the temporary sealing is performed. In the manufacturing method of a sealed battery that releases and temporarily seals the liquid injection hole after performing a series of steps including the temporary sealing, the battery adjustment, and the temporary sealing cancellation at least once,
The temporary sealing is performed by sealing a temporary sealing member around the liquid injection hole, and the main sealing is performed at a position different from the position where the temporary sealing member is sealed. A method for producing a sealed battery, wherein the sealing member is sealed around a hole. The method for manufacturing a sealed battery according to claim 1, wherein a position where the main sealing member is sealed is outside a position where the temporary sealing member is sealed. The method for manufacturing a sealed battery according to claim 1, wherein a position where the main sealing member is sealed is inside a position where the temporary sealing member is sealed. A sealed outer container including a liquid injection hole;
A power generation element housed in the exterior container;
In a sealed battery comprising a sealing member formed by sealing the liquid injection hole,
The sealing member is used to temporarily seal the liquid injection hole and is sealed around the liquid injection hole, and the outside of the position where the temporary sealing member is sealed A sealed battery including a main sealing member sealed to fully seal the liquid injection hole at the position.

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