Secondary battery

• US 7,998,612 B2
• Filed: 06/02/2010
• Issued: 08/16/2011
• Est. Priority Date: 01/31/2008
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Sumihara, Masanori, Imai, Tadashi
• Primary Examiner(s): Gilliam; Barbara L
• Assistant Examiner(s): WALLEN, THOMAS J
• Application Number:
  US12/792,371
• Publication Number:
  US 20100239897A1
• Time in Patent Office: 440 Days
• Field of Search: 429/7, 429 53- 57, 429/94
• US Class Current: 429/172
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 50/528 Fixed electrical connections, i.e. not intended for disconnection
• CPC Class Codes: H01M 50/538 Connection of several leads or tabs of wound or folded electrode stacks
• CPC Class Codes: H01M 50/56 Cup shaped terminals
• 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

Abstract

An electrode group is constructed by disposing a positive electrode current collector exposed portion on one end side and a negative electrode current collector exposed portion on the other end side. A positive electrode current collector terminal plate and a negative electrode current collector terminal plate are connected to the positive and negative electrode current collector exposed portions, respectively. A conductive coned disc spring is disposed compressed between the positive electrode current collector terminal plate and a sealing plate. The coned disc spring has a dead zone in which the elastic force does not change according to the amount of deformation, and urges the negative electrode current collector terminal plate toward a bottom portion of a battery case with a defined elastic force.

Claims

1. A secondary battery comprising:

an electrode group that includes a positive electrode plate and a negative electrode plate that are constructed by forming a material mixture layer made of an electrode material mixture that contains an active material on one surface or both surfaces of a strip-shaped current collector, and forming an exposed portion in which a surface of said current collector is exposed in one end portion in a width direction of said current collector, and a separator that is interposed between said positive electrode plate and said negative electrode plate, said electrode group being constructed by spirally winding or laminating said positive electrode plate, said negative electrode plate and said separator;

a positive electrode current collector terminal plate that is disposed on one end side of said electrode group and is connected to said current collector exposed portion of said positive electrode plate;

a negative electrode current collector terminal plate that is disposed on the other end side of said electrode group and is connected to said current collector exposed portion of said negative electrode plate;

an electrolyte;

a battery case that has a bottom portion and an opening portion disposed opposite to said bottom portion, is connected to one of said positive electrode current collector terminal plate and said negative electrode current collector terminal plate, and houses said electrode group, said positive electrode current collector terminal plate, said negative electrode current collector terminal plate and said electrolyte;

a sealing plate that is connected to the other of said positive electrode current collector terminal plate and said negative electrode current collector terminal plate and seals the opening portion in an insulated state from said battery case; and

one or more elastic members that have conductivity, are disposed at least one of between said the bottom portion of said battery case and one of said current collector terminal plates and between said sealing plate and the other of said current collector terminal plates, electrically connect members that sandwich the elastic member, bias said electrode group toward said bottom portion of said battery case or said sealing plate, have a dead zone in which an elastic force does not fluctuate according to an amount of deformation in a range from a first predetermined amount X to a second predetermined amount Y, wherein 0<

x<

Y, and are compressed upon installation to the extent that the amount of deformation is within said dead zone.

2. The secondary battery in accordance with claim 1, wherein said elastic member is configured of a coned disc spring that has a slit in a peripheral portion.

3. The secondary battery in accordance with claim 2, wherein at least one of said positive electrode current collector terminal plate and said negative electrode current collector terminal plate has a protrusion that engages in the slit of said coned disc spring.

4. The secondary battery in accordance with claim 1, wherein said elastic member is covered with at least one metal selected from chromium and nickel.