Composite sheet electrode

• US 5,489,492 A
• Filed: 08/01/1994
• Issued: 02/06/1996
• Est. Priority Date: 05/08/1991
• Status: Expired due to Term

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited, Unitika Limited
• Inventors: Kabata, Toshiyuki, Kimura, Okitoshi, Inoue, Katsuo, Takahashi, Hideki, Asami, Keiichi, Echigo, Yoshiaki, Ohsawa, Toshiyuki
• Primary Examiner(s): Willis, Jr., Prince
• Assistant Examiner(s): NUZZOLILLO, MARIA
• Application Number:
  US08/285,121
• Time in Patent Office: 554 Days
• Field of Search: 429/212, 429/213, 429/215, 429/218, 429/232, 429/233, 429/235, 429/241, 429/245
• US Class Current: 429/212
• CPC Class Codes: H01M 4/02 Electrodes composed of, or comprising, active material
• CPC Class Codes: H01M 4/60 of organic compounds
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: H01M 4/66 Selection of materials
• CPC Class Codes: H01M 4/668 Composites of electroconductive material and synthetic resins
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The present invention provides a composite sheet electrode which has high strength, excellent current collecting properties and which is used efficiently as an active material for an electrode. The electrode has excellent discharge capacities and can be easily formed into an electrode terminal. A cell employing this electrode is also disclosed. The invention also provides a composite sheet electrode having a porosity of 20 to 80% containing 5 to 95% by weight of an active material of an electrode, 1 to 50% by weight of a current collecting material and heat fusible short fibers. The present invention also provides a composite sheet electrode having a porosity of 20 to 80%, which is made up of a composite sheet containing 5 to 95% by weight of an active material as an electrode and 5 to 95% by weight of heat fusible short fibers, as well as a current collecting material layer formed on said composite sheet. The present invention further provides a cell employing the latter-mentioned composite sheet electrode.

Claims

1. A composite sheet electrode having a porosity of 20 to 80%, which comprises:

(a) a composite sheet comprising a mixture of 5 to 95% by weight of an active electrode material and 5 to 95% by weight of heat fusible fibers, wherein said active electrode material is selected from the group consisting of a transition metal oxide, a transitional metal chalcogenide compound other than transition metal oxide, a combination thereof with Li, a graphite compound prepared from carbonized organic compounds, carbon fluoride, graphite and an electroconductive polymer having an electronductivity of 10^-2 S/cm, and wherein said heat fusible fibers have a length of 0.1 to 50 mm and are selected from the group consisting of a polyester, a polyamide, a polyolefin, a polyvinyl alcohol, a synthetic pulp, a polyester fiber covered with a low melting point polymer, a polyamide covered with a low melting point polymer, and mixtures of said fibers, and

(b) a current collecting material layer laminated on said composite sheet, wherein said current collecting material is selected from the group consisting of carbon black, glassy carbon powder, graphite powder, carbon fiber, metal powder, metal fiber, and mixtures thereof.

2. The composite sheet electrode according to claim 1 wherein said composite sheet and said current collecting material layer are bonded with a bonding layer.

3. The composite sheet electrode according to claim 1 wherein said composite sheet and said current collecting material layer are bonded with a bonding layer.

4. In a cell comprising a positive electrode, a negative electrode and a electrolyte solution, the improvement wherein the composite sheet electrode according to claim 1 is used as an electrode.

5. In a cell comprising a positive electrode, a negative electrode and an electrolytic solution, the improvement wherein the composite sheet electrode according to claim 2 is used as an electrode.

6. The composite sheet electrode according to claim 1 in which the fiber lengths are within the range of 1 to 25 mm.

7. A cell according to claim 4 in which the composite sheet electrode is the positive electrode.

8. A cell according to claim 5 in which the composite sheet electrode is the positive electrode.