Battery tab attachment method

• US 6,458,171 B1
• Filed: 10/19/1999
• Issued: 10/01/2002
• Est. Priority Date: 04/16/1999
• Status: Expired due to Fees

• Current Assignee: Quallion, LLC (EnerSys)
• Original Assignee: Quallion, LLC (EnerSys)
• Inventors: Tsukamoto, Hisashi
• Primary Examiner(s): Kalafut, Stephen
• Assistant Examiner(s): ALEJANDRO, RAYMOND
• Application Number:
  US09/421,472
• Time in Patent Office: 1,078 Days
• Field of Search: 429/211, 429/209, 429/218.1, 429/231.5, 429/161, 296/231, 296/233, 296/234
• US Class Current: 29/623.4
• CPC Class Codes: H01M 4/661 Metal or alloys, e.g. alloy coatings H01M4/669 take precedence
• CPC Class Codes: H01M 4/667 in the form of layers, e.g. coatings
• CPC Class Codes: H01M 4/668 Composites of electroconductive material and synthetic resins
• CPC Class Codes: H01M 50/534 characterised by the material of the leads or tabs
• CPC Class Codes: H01M 6/40 Printed batteries , e.g. thin film batteries
• CPC Class Codes: Y10T 29/49108 Electric battery cell making
• CPC Class Codes: Y10T 29/49114 including adhesively bonding

Abstract

The difficulties encountered with attaching tabs to very thin metal layer. e. g., a layer of gold from 0.3 μm to 50 μm thick are severe. Typically, in the uses envisioned for the thin metal layer, which is for a compact battery, a plastic sheet such as polyimide underlies the thin metal layer. Polyimide has a relatively low melting point. The thin polyimide substrate melts when resistance welding is used. Ultrasonic welding doesn'"'"'t work because the sound wave energy is absorbed by the polyimide. This invention solves the attachment problem by using wire bonding to the thin metal sheet and to its tab. The tab attachment for a thin metal layer comprises a thin metal layer, a metal tab, and a wire and the wire is bonded to the thin metal layer and the wire is bonded to the metal tab. The thin metal layer may be gold; the thickness of the gold is between 0.3 μm and 50.0 μm.

Claims

1. A method for attaching a metal tab to a thin metal layer laminated on a thin plastic layer, said method comprising the steps of:

wire bonding a first end of a wire to said thin metal layer; and

wire bonding a second end of said wire to said metal tab;

wherein

said thin metal layer has a thickness of between 0.3 μ

m and 50 μ

m.

2. The method of claims 1 wherein said thin metal layer comprises a material selected from the group consisting of gold, aluminum, titanium, iron, and stainless steel.

3. The method of claim 1 wherein said wire comprises a material selected from the group consisting of gold, aluminum, titanium, iron, and stainless steel.

4. The method or claim 1 wherein said wire has a diameter of between 10 μ

m and 50 μ

m.

5. The method of claim 1 wherein said tab comprises a material selected from the group consisting of gold, aluminum, titanium, iron, and stainless steel.

6. The method of claim 1 wherein said tab has a thickness of between 30 μ

m and 80 μ

m.