Manufacturing method of secondary battery, secondary battery, and assembled battery

Patent metadata

Field	Value
Publication number	US-9812686-B2
Application number	US-201113806995-A
Country	US
Kind code	B2
Filing date	Jun 22, 2011
Priority date	Jun 30, 2010
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

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.

First claim

The invention claimed is:

1. A secondary battery comprising:
a case;
a lid formed in an opening of the case, and comprising a safety valve and an opening portion;
a first sealing body formed in 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 the first sealing body being displaced to allow the inside air to flow out of the case through the opening portion, by an internal pressure which is less than an actuation pressure of the safety valve; and
a second sealing body comprising a sealing plate formed on the opening portion and welded to the lid so as to seal the opening portion, the second sealing body being resistant to an internal pressure greater than the actuation pressure of the safety valve,
wherein the first sealing body and the second sealing body are fixed to each other, and
wherein the opening portion comprises a first portion and a second portion having a width which is greater than a width of the first portion.

2. The secondary battery according to claim 1 , wherein the safety valve releases inside air in the case when the internal pressure in the case becomes higher than the actuation pressure, 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.

3. The secondary battery according to claim 1 , 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.

4. The secondary battery according to claim 1 , 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.

5. The secondary battery according to claim 1 , 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.

6. The secondary battery according to claim 1 , wherein the opening portion is formed as an electrolyte solution filling opening through which an electrolyte solution is filled into the case.

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

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

9. An assembled battery comprising a plurality of secondary batteries according to claim 1 .

10. The secondary battery according to claim 1 , wherein the opening portion comprises an electrolyte solution filling opening.

11. The secondary battery according to claim 1 , wherein the first sealing body comprises:
a base portion formed in the second portion of the opening portion; and
a protruding portion having a width which is less than a width of the base portion, and protruding from the base portion into the first portion of the opening portion.

12. A secondary battery comprising:
a case;
a lid formed on the case and comprising a safety valve and an opening;
a first sealing body formed in the opening such that the first sealing body is displaced to allow a gas inside the case to flow out of the case through the opening, by an internal pressure which is less than an actuation pressure of the safety valve; and
a second sealing body comprising a sealing plate formed on the opening and welded to the lid so as to seal the opening, the second sealing body being resistant to an internal pressure greater than the actuation pressure of the safety valve,
wherein the first sealing body and the second sealing body are fixed to each other, and
wherein the opening comprises:
a first portion formed at an inner surface of the lid; and
a second portion having a width which is greater than a width of the first portion, formed at an outer surface of the lid, the second portion comprising a bottom surface which surrounds the first portion and is substantially coplanar with the outer surface of the lid.

13. The secondary battery according to claim 1 , wherein the case comprises a can body and the lid is formed on an opening of the can body, and the opening portion is formed in the lid of the case,
wherein the
second portion is formed at an outer surface of the lid, the second portion comprising a bottom surface which surrounds the first portion and is substantially coplanar with the outer surface of the lid,
wherein the first sealing body comprises:
a base portion formed in the second portion of the opening portion and being seated on the bottom surface of the second portion; and
a protruding portion having a width which is less than a width of the base portion, and protruding from a center of the base portion into the first portion of the opening portion, and
wherein the sealing plate is formed over the second portion of the opening portion, is fixed to the base portion of the first sealing body, and is welded to the outer surface of the lid.

14. The secondary battery according to claim 1 , further comprising:
a terminal passing through an electrode mounting hole of the lid, the safety valve being formed in a central portion of the lid and the opening portion being formed between the safety valve and the electrode mounting hole.

15. The secondary battery according to claim 1 , wherein an outer diameter of the sealing plate is greater than an outer diameter of the opening portion.

16. The secondary battery according to claim 1 , wherein an edge of the sealing plate is welded to the lid along an entire circumference of the sealing plate to achieve an airtight seal.

17. The secondary battery according to claim 11 , wherein a space for retaining leaked electrolyte solution is formed in the opening portion, the space being def

Assignees

• Kako Tomonori
• Mori Sumio
• Gs Yuasa Int Ltd

Inventors

• Kako Tomonori
• Mori Sumio

Classifications

• H01M50/636

  Closing or sealing filling ports, e.g. using lids · CPC title

• H01M2/0217

  Electricity · mapped topic

• H01M10/04

  Construction or manufacture in general (H01M10/058, H01M10/12, H01M10/28, H01M10/38 take precedence) · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/058 Primary

  Construction or manufacture · CPC title