Electrochemical cell

• US 20040241542A1
• Filed: 05/12/2004
• Published: 12/02/2004
• Est. Priority Date: 05/30/2003
• Status: Active Grant

• Current Assignee: Seiko Instruments Incorporated (Seiko Group)
• Original Assignee: Seiko Instruments Incorporated (Seiko Group)
• Inventors: Tahara, Kensuke, Onodera, Hideharu, Watanabe, Shunji, Nakamura, Yoshibumi, Sakai, Tsugio
• Granted Patent: US 7,311,995 B2
• Time in Patent Office: Days
• US Class Current: 429/181
• CPC Class Codes: H01M 50/103 prismatic or rectangular H01M50/109, H01M50/11 take precedence
• CPC Class Codes: H01M 50/117 Inorganic material
• CPC Class Codes: H01M 50/169 by welding, brazing or soldering
• CPC Class Codes: H01M 50/55 on the same side of the cell
• CPC Class Codes: H01M 50/553 Terminals adapted for prismatic, pouch or rectangular cells
• CPC Class Codes: H01M 50/564 characterised by their manufacturing process
• 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

In an electrochemical cell, a highly reliable sealing by welding was not possible with a sealing plate of aluminum, stainless steel or nickel resistant to cathodic corrosion, because of a significant thermal expansion as the welded portion of the sealing plate and the outer case is heated to a high temperature. A sealing plate resistant to cathodic corrosion, serving also as a negative pole current-collecting member, can be obtained by employing an alloy containing Co by 1 to 50 wt. %, and using it in combination with a ceramic package, and a highly reliable sealing can be realized by executing a seam welding utilizing resistance welding.

Claims

1. An electrochemical cell comprising:

an electrochemical cell element including a pair of electrodes containing a positive pole and a negative pole, and a non-aqueous electrolyte; and

an outer case and a sealing plate for hermetically sealing said electrochemical cell element;

wherein said outer case is formed by ceramics or glass;

said sealing plate is formed by a metal plate serving also as a negative pole current-collecting member or a metal or an insulating member provided on at least a surface thereof with a metal layer constituting a negative pole current-collecting member; and

said negative pole current-collecting member is formed by a material of a thermal expansion coefficient approximately equal to that of said outer case.

12. An electrochemical cell according to claim 1, comprising a conductive layer electrically connected with either one of said positive pole and said negative pole, wherein a connecting terminal electrically connected with said conductive layer is formed by patterning on an external surface of said outer case.

13. An electrochemical cell according to claim 1, wherein a first conductive layer electrically connected with said positive pole is formed on an internal bottom surface of said outer case, a second conductive layer electrically connected with said negative pole is formed on said sealing plate, and, on an external surface of said outer case, a first connecting terminal electrically connected with said first conductive layer and a second connecting terminal electrically connected with said second conductive layer are formed by patterning.

2. An electrochemical cell comprising:

an electrochemical cell element including a pair of electrodes containing a positive pole and a negative pole, and a non-aqueous electrolyte; and

an outer case and a sealing plate for hermetically sealing said electrochemical cell element;

wherein said sealing plate is formed by a metal plate serving also as a negative pole current-collecting member or a metal or an insulating member provided on at least a surface thereof with a metal layer constituting a negative pole current-collecting member; and

said negative pole current-collecting member is formed by an alloy containing, in weight percentage (wt. %), Co by 1 to 50%, Ni by 1 to 70%, Fe by 20% or higher, Cr by 10% or lower, Mn by 2.0% or lower, Si by 1.0% or lower and C by 1.0% or lower.

3. An electrochemical cell according to claim 2, wherein said outer case is formed by ceramics or glass.

4. An electrochemical cell according to claim 2, wherein the alloy employed in said negative pole current-collecting member has a thermal expansion coefficient within a range of −

2 to 11×

10<sup>−

6</sup>/°

C. (0-300°

C.).

5. An electrochemical cell according to claim 4,

wherein the alloy employed in said negative pole current-collecting member bears a plating of at least one of Ni, Au, W and Cr, and said outer case and said sealing plate are sealed by adjoining by resistance welding.

6. An electrochemical cell according to claim 5, further comprising a solder material provided on said plating, wherein said outer case and said sealing plate are sealed by adjoining by resistance welding.

7. An electrochemical cell according to claim 6, wherein said solder material is formed by a thick film method utilizing a plating process or a printing process.

8. An electrochemical cell according to claim 2, comprising a conductive layer electrically connected with either one of said positive pole and said negative pole, wherein a connecting terminal electrically connected with said conductive layer is formed by patterning on an external surface of said outer case.

9. An electrochemical cell according to claim 2,

wherein a first conductive layer electrically connected with said positive pole is formed on an internal bottom surface of said outer case, a second conductive layer electrically connected with said negative pole is formed on said sealing plate, and, on an external surface of said outer case, a first connecting terminal electrically connected with said first conductive layer and a second connecting terminal electrically connected with said second conductive layer are formed by patterning.

10. An electrochemical cell according to claim 3, wherein the alloy employed in said negative pole current-collecting member bears a plating of at least one of Ni, Au, W and Cr, and said outer case and said sealing plate are sealed by adjoining by resistance welding.

11. An electrochemical cell according to claim 2, wherein the alloy employed in said negative pole current-collecting member bears a plating of at least one of Ni, Au, W and Cr, and said outer case and said sealing plate are sealed by adjoining by resistance welding.