MANUFACTURING METHOD OF SECONDARY BATTERY, SECONDARY BATTERY, AND ASSEMBLED BATTERY

• US 20130130079A1
• Filed: 06/22/2011
• Published: 05/23/2013
• Est. Priority Date: 06/30/2010
• Status: Active Grant

• Current Assignee: GS Yuasa International Ltd. (GS Yuasa Corporation)
• Original Assignee: Tomonori Kako
• Inventors: Mori, Sumio, Kako, Tomonori
• Granted Patent: US 9,812,686 B2
• Time in Patent Office: Days
• US Class Current: 429/82
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/058 Construction or manufacture
• CPC Class Codes: H01M 50/103 prismatic or rectangular H01M50/109, H01M50/11 take precedence
• CPC Class Codes: H01M 50/317 Re-sealable arrangements
• CPC Class Codes: H01M 50/636 Closing or sealing filling ports, e.g. using lids
• CPC Class Codes: H01M 50/668 Means for preventing spilling of liquid or electrolyte, e.g. when the battery is tilted or turned over
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 29/4911 including sealing

Abstract

A secondary battery includes an opening portion provided to a case. A first sealing body is provided to the opening portion, the first sealing body being displaced or deformed by a pressure difference between an inside and an outside of the case in such manners that the first sealing body is pressed by internal pressure to allow outflow of inside air from the opening portion when the internal pressure in the case is higher than external pressure and that the first sealing body is pressed by the external pressure to prevent entry of outside air from the opening portion when the internal pressure in the case is lower than the external pressure. Pressure in a space surrounded with the case and the first sealing body is set to be lower than pressure outside the space.

Claims

1. A manufacturing method of a secondary battery, the manufacturing method comprising:

a gas releasing step of releasing gas from an opening portion formed at a case of a secondary battery,

wherein, in the gas releasing step,

a first sealing body is attached to the opening portion, the first sealing body being displaced or deformed by a pressure difference between an inside and an outside of the case in such manners that the first sealing body is pressed by internal pressure to allow outflow of inside air from the opening portion when the internal pressure in the case is higher than external pressure and that the first sealing body is pressed by the external pressure to prevent entry of outside air from the opening portion when the internal pressure in the case is lower than the external pressure,

the case to which the first sealing body is attached is disposed in a reduced pressure environment to allow gas in the case to flow out of the case through an attached position of the first sealing body, and

the case is returned into a normal pressure environment, after the gas in the case flows out, and the opening portion is sealed.

2. The manufacturing method of the secondary battery according to claim 1, wherein the case is in a shape of a flat rectangular parallelepiped.

3. The manufacturing method of the secondary battery according to claim 1,

wherein, in the gas releasing step,

the opening portion is sealed while a space where the first sealing body exists is covered with a second sealing body after the case is returned into the normal pressure environment.

4. The manufacturing method of the secondary battery according to claim 3, wherein the sealing by the second sealing body is carried out by welding the second sealing body and the case together.

5. The manufacturing method of the secondary battery according to claim 3, wherein the first sealing body and the second sealing body are fixed to each other.

6. The manufacturing method of the secondary battery according to claim 3,

wherein the second sealing body is formed into a plate shape, and a portion of the second sealing body is fixed to the case before the case is returned into the normal pressure environment.

7. The manufacturing method of the secondary battery according to claim 1, wherein the case is made of metal.

8. A secondary battery comprising an opening portion provided to a case,

wherein a first sealing body is provided to the opening portion, the first sealing body being displaced or deformed by a pressure difference between an inside and an outside of the case in such manners that the first sealing body is pressed by internal pressure to allow outflow of inside air from the opening portion when the internal pressure in the case is higher than external pressure and that the first sealing body is pressed by the external pressure to prevent entry of outside air from the opening portion when the internal pressure in the case is lower than the external pressure, and

pressure in a space surrounded with the case and the first sealing body is set to be lower than pressure outside the space.

9. The secondary battery according to claim 8, further comprising a second sealing body for sealing a space where the first sealing body exists while covering the space,

wherein the second sealing body and the case are welded together.

10. The secondary battery according to claim 9,

wherein the case is provided with a safety valve for releasing inside air in the case when the internal pressure in the case becomes higher than predetermined actuation pressure,

the second sealing body is resistant to higher pressure than the actuation pressure of the safety valve, and

the pressure difference which is between the inside and the outside of the case and at which the first sealing body starts the outflow of the inside air is set to be smaller than a pressure difference which is between the inside and the outside of the case and at which the safety valve starts outflow of the inside air.

11. The secondary battery according to claim 9, further comprising a retaining portion for retaining an electrolyte solution, which leaks from an attached position of the first sealing body, between the attached position of the first sealing body and an attached position of the second sealing body.

12. The secondary battery according to claim 9, wherein the first sealing body and the second sealing body are fixed to each other.

13. The secondary battery according to claim 9, wherein the second sealing body is formed into a plate shape.

14. The secondary battery according to claim 8,

wherein the first sealing body includes a guided portion to be loosely fitted with a guide portion of the opening portion and an airtightness maintaining portion to be pressed by an external force and brought into contact with the opening portion or the case to maintain airtightness, and

the airtightness maintaining portion is pressed by the internal pressure when the internal pressure in the case is higher than the external pressure and by the external pressure when the internal pressure in the case is lower than the external pressure and displaced to be separated from the opening portion and to be pressed against the opening portion, respectively, while the guided portion is guided by the guide portion of the opening portion.

15. The secondary battery according to claim 8,

wherein the first sealing body is disposed in such a posture as to cover, from an outer side with respect to the case, a through hole of the opening portion penetrating the case between an inside and an outside, and

the first sealing body is formed to allow the outflow of the inside air in the case through a gap between a face of the first sealing body in contact with a periphery of the through hole and the opening portion when the internal pressure in the case is higher than the external pressure and to be pressed by the external pressure and elastically deformed to come in close contact with the periphery of the through hole to prevent the entry of the outside air when the internal pressure in the case is lower than the external pressure.

16. The secondary battery according to claim 8, wherein the opening portion is formed as an electrolyte solution filling opening through which an electrolyte solution is filled into the case.

17. The secondary battery according to claim 8, wherein the case is in a shape of a flat rectangular parallelepiped.

18. The secondary battery according to claim 8, wherein the case is made of metal.

19. An assembled battery comprising a plurality of secondary batteries according to claim 8.