FLAT SECONDARY BATTERY AND METHOD OF MANUFACTURING THE SAME

• US 20110129722A1
• Filed: 07/02/2009
• Published: 06/02/2011
• Est. Priority Date: 07/09/2008
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yoneda, Tetsuya
• Application Number:
  US13/003,379
• Publication Number:
  US 20110129722A1
• Time in Patent Office: Days
• US Class Current: 429/162
• CPC Class Codes: H01M 10/0436 Small-sized flat cells or batteries for portable equipment
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 10/30 Nickel accumulators H01M10/34 takes precedence
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• 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 50/417 Polyolefins
• CPC Class Codes: H01M 50/44 Fibrous material
• CPC Class Codes: H01M 50/46 Separators, membranes or diaphragms characterised by their combination with electrodes
• 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
• CPC Class Codes: Y10T 29/4911 including sealing

Abstract

A flat secondary battery comprising: a positive electrode plate; a negative electrode plate opposed to the positive electrode plate; an electrolytic solution being present between the electrode plates; a separator interposed between the electrode plates; and a covering material for sealing the electrolytic solution, wherein

• • the positive electrode plate includes: a positive-electrode current-collector sheet whose peripheral area has a bonding area bonded to a peripheral area of the separator; and a positive-electrode active-material layer laminated on a non-bonding area of one surface or both surfaces of the positive-electrode current-collector sheet,
  • the negative-electrode plate includes: a negative-electrode current-collector sheet whose peripheral area has a bonding area bonded to the peripheral area of the separator; and a negative-electrode active-material layer laminated on a non-bonding area of one surface or both surfaces of the negative-electrode current-collector sheet and having a sufficient size to cover the positive-electrode active-material layer, and
  • the peripheral areas of both surfaces of the separator are bonded to the bonding areas of the positive-electrode current-collector sheet and the negative-electrode current-collector sheet to maintain a state in which an area of the negative-electrode active-material layer entirely covers an area of the positive-electrode active-material layer so that a battery module is formed.

Claims

1. A flat secondary battery comprising:

a positive electrode plate;

a negative electrode plate opposed to the positive electrode plate;

an electrolytic solution being present between the electrode plates;

a separator interposed between the electrode plates; and

a covering material for sealing the electrolytic solution,

wherein the positive electrode plate includes;

a positive-electrode current-collector sheet whose peripheral area has a bonding area bonded to a peripheral area of the separator; and

a positive-electrode active-material layer laminated on a non-bonding area of one surface or both surfaces of the positive-electrode current-collector sheet,

the negative-electrode plate includes;

a negative-electrode current-collector sheet whose peripheral area has a bonding area bonded to the peripheral area of the separator; and

a negative-electrode active-material layer laminated on a non-bonding area of one surface or both surfaces of the negative-electrode current-collector sheet and having a sufficient size to cover the positive-electrode active-material layer, and

the peripheral areas of both surfaces of the separator are bonded to the bonding areas of the positive-electrode current-collector sheet and the negative-electrode current-collector sheet to maintain a state in which an area of the negative-electrode active-material layer entirely covers an area of the positive-electrode active-material layer so that a battery module is formed.

2. The flat secondary battery according to claim 1, wherein the positive-electrode current-collector sheet and the negative-electrode current collector sheet each have plural bonding areas.

3. The flat secondary battery according to claim 1, wherein

the positive-electrode current-collector sheet, the negative-electrode current-collector sheet, and the separator each are quadrangular,

the peripheral area of the positive-electrode current-collector sheet and the peripheral area of the separator are bonded to each other at one side thereof, at two sides thereof opposite to each other, at two or more sides thereof adjacent to one another, in the vicinity of two corners thereof opposite to each other, or in the vicinity of three or more corners thereof, and

the peripheral area of the negative-electrode current-collector sheet and the peripheral area of the separator are bonded to each other at one side thereof, at two sides thereof opposite to each other, at two or more sides thereof adjacent to one another, in the vicinity of two corners thereof opposite to each other, or in the vicinity of three or more corners thereof.

4. The flat secondary battery according to claim 3, wherein

the negative-electrode current-collector sheet is formed in a size larger than the positive-electrode current-collector sheet, and

the separator is formed in a size equal to the negative-electrode current-collector sheet.

5. The flat secondary battery according to claim 1, wherein

the positive-electrode current-collector sheet and the negative-electrode current-collector sheet each are made of a conductive sheet where at least its surface is metal,

the separator is made of a resin material, and

the separator is bonded to the positive-electrode current-collector sheet and the negative-electrode current-collector sheet by ultrasonic welding, heat fusion, or thermo-compression bonding.

6. The flat secondary battery according to claim 5, wherein

the positive-electrode current-collector sheet and the negative-electrode current-collector sheet each comprise:

a resin film made of at least one kind of a resin material selected from polypropylene, polyethylene, polyethylene terephthalate, nylon, polyamide and polyimide; and

a metal film laminated on a surface of the resin film, and

the resin film of the positive-electrode current-collector sheet and the negative-electrode current-collector sheet each is bonded to the separator.

7. The flat secondary battery according to claim 4, wherein

the separator is in the form of a bag and contains:

a first separator bonded to the positive-electrode current-collector sheet and the negative-electrode current-collector sheet; and

a second separator bonded to a peripheral area of one surface of the first separator,

the positive-electrode current-collector sheet is bonded to one surface of the first separator in the bag-like separator, and

the negative-electrode current-collector sheet is bonded to another surface of the first separator.

8. The flat secondary battery according to claim 7, wherein

the positive electrode plate has the positive-electrode active-material layer on both surfaces of the positive-electrode current-collector sheet, and the negative electrode plate has the negative-electrode active-material layer on both surfaces of the negative-electrode current-collector sheet,

the battery module is formed by bonding the positive-electrode current-collector sheet of the positive electrode plate to the one surface of the first separator in the bag-like separator, and bonding the negative-electrode current-collector sheet of the negative electrode plate to the another surface of the first separator, and

a plurality of such battery modules are stacked on one another in the covering material.

9. The flat secondary battery according to claim 1, wherein a plurality of battery modules are stacked on one another in the covering material.

10. A method of manufacturing a flat secondary battery, comprising the steps of:

(A) laminating a positive-electrode active-material layer on a non-bonding area, which does not bond to a separator, of one surface or both surfaces of a positive-electrode current-collector sheet to form a positive electrode plate, and attaching a lead plate to the positive-electrode current-collector sheet;

(B) laminating a negative-electrode active-material layer on a non-bonding area, which does not bond to the separator, of one surface or both surfaces of a negative-electrode current-collector sheet to form a negative electrode plate, and attaching a lead plate to the negative-electrode current-collector sheet;

(C) bonding a bonding area in a peripheral area of the positive-electrode current-collector sheet and the negative-electrode current-collector sheet each to peripheral areas of both surfaces of the separator to form a battery module; and

(D) enclosing the battery module in a covering material having an electrolytic solution inlet in a state to expose an end of each lead plate to the outside of the covering material, injecting an electrolytic solution into the covering material through the electrolytic solution inlet, and sealing the electrolytic solution inlet.

11. The method according to claim 10, wherein

in step (A), the positive-electrode active-material layer is laminated on the non-bonding area of each of the both surfaces of the positive-electrode current-collector sheet to form the positive electrode plate,

in step (B), the negative-electrode active-material layer is laminated on the non-bonding area of each of the both surfaces of the negative-electrode current-collector sheet to form the negative electrode plate,

step (C) includes the steps of:

bonding the positive-electrode current-collector sheet to a peripheral area of one surface of a first separator and bonding a second separator to the peripheral area of the first separator to cover the positive electrode plate; and

bonding the negative-electrode current-collector sheet to a peripheral area of another surface of the first separator, so as to form a plurality of battery modules, and

in step (D), the plurality of battery modules stacked on one another are enclosed in the covering material.

12. The method according to claim 10, wherein, in step (C), the separator is bonded to the positive-electrode current-collector sheet and the negative-electrode current-collector sheet by ultrasonic welding, heat fusion, or thermo-compression bonding.