Cell structure for electrochemical devices and method of making same

• US 20070160901A1
• Filed: 03/06/2007
• Published: 07/12/2007
• Est. Priority Date: 07/13/2001
• Status: Active Grant

• Current Assignee: Inventec Corporation
• Original Assignee: Inventex Corporation
• Inventors: Kaun, Thomas
• Granted Patent: US 8,021,775 B2
• Time in Patent Office: Days
• US Class Current: 429/130
• CPC Class Codes: H01M 10/0413 Large-sized flat cells or batteries for motive or stationary systems with plate-like electrodes
• CPC Class Codes: H01M 10/0431 Cells with wound or folded electrodes H01M10/045 takes precedence
• CPC Class Codes: H01M 10/045 Cells or batteries with folded plate-like electrodes
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0583 of accumulators with folded construction elements except wound ones, i.e. folded positive or negative electrodes or separators, e.g. with "Z"-shaped electrodes or separators
• CPC Class Codes: H01M 10/0587 of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/625 Vehicles
• CPC Class Codes: H01M 10/643 Cylindrical cells
• CPC Class Codes: H01M 10/654 located inside the innermost case of the cells, e.g. mandrels, electrodes or electrolytes
• CPC Class Codes: H01M 10/6556 Solid parts with flow channel passages or pipes for heat exchange closed pipes H01M10/6552
• CPC Class Codes: H01M 10/6557 arranged between the cells
• CPC Class Codes: H01M 10/6567 Liquids
• CPC Class Codes: H01M 50/171 using adhesives or sealing agents
• CPC Class Codes: H01M 50/325 comprising deformable valve members, e.g. elastic or flexible valve members
• CPC Class Codes: H01M 50/449 having a layered structure
• CPC Class Codes: H01M 50/469 tubular or cylindrical
• CPC Class Codes: H01M 50/56 Cup shaped terminals
• CPC Class Codes: H01M 6/10 : with wound or folded electrodes
• CPC Class Codes: H01M 6/5038 : Heating or cooling of cells or batteries
• 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 electrochemical device comprising alternating layers of positive and negative electrodes separated from each other by separator layers. The electrode layers extend beyond the periphery of the separator layers providing superior contact between the electrodes and battery terminals, eliminating the need for welding the electrode to the terminal. Electrical resistance within the battery is decreased and thermal conductivity of the cell is increased allowing for superior heat removal from the battery and increased efficiency. Increased internal pressure within the battery can be alleviated without damaging or removing the battery from service while keeping the contents of the battery sealed off from the atmosphere by a pressure release system. Nonoperative cells within a battery assembly can also be removed from service by shorting the nonoperative cell thus decreasing battery life.

Claims

1. An electrochemical device, comprising:

an electrode assembly comprising;

an elongated positive electrode with a first longitudinal edge;

an elongated negative electrode with a first longitudinal edge; and

a separation layer having a first longitudinal edge and a second longitudinal edge;

wherein the positive electrode, the separation layer, and the negative electrode are wound around a central axis thereby forming a coil of alternating electrode and separation layers such that the separation layer prevents direct contact between successive electrode layers, the first longitudinal edge of the separation layer extends beyond the first longitudinal edge of the separation layer, and the first longitudinal edge of the negative electrode extends beyond the second longitudinal edge of the separation layer;

the electrode assembly being slightly wider than the plates of the housing; and

a housing having a positive plate electrically coupled to the first longitudinal edge of the positive electrode and a negative plate electrically coupled to the first longitudinal edge of the negative electrode, wherein the electrode assembly is enclosed by the housing.

2. The device of claim 1, wherein the separation layer is tensioned.

3. The device of claim 1, wherein the separation layer comprises two layers.

4. The device of claim 1, wherein an outer plastic band surrounds the electrode assembly circumferentially, wherein the outer plastic band retains the electrode.

5. The electrochemical device of claim 1, wherein the housing includes a first cup including the positive plate, a second cup including the negative plate, wherein the first cup and the second cup are joined together to form the housing such that the first and second cups are electrically isolated from one another and further wherein the positive plate and negative plate are generally planar.

6. The electrochemical device of claim 5, wherein the electrode assembly is sealed from ambient atmosphere by the housing.

7. The electrochemical device of claim 6, further comprising a pressure release feature which relieves pressure build-up within the housing when the pressure within the housing reaches a predetermined limit, wherein the electrochemical device is still operable after the pressure build-up within the housing is released.

8. The electrochemical device of claim 1, further comprising a component coupled to the electrode assembly for shorting the electrode assembly when the electrode assembly becomes nonoperative.

9. An electrochemical device, comprising:

an electrode assembly, comprising a positive electrode and a negative electrode;

a housing coupled to and enclosing the electrode assembly to form an electrochemical cell;

the housing consists of a first telescoping half and a second telescoping half wherein the electrode is disposed therebetween.

a peripheral seal separating the housing and the electrode and maintaining an airtight seal, the seal comprising a low melting point polymeric material and serving to short the cell under predetermined conditions;

wherein upon placement in a vacuum, the telescoping halves extend allowing for disassembly of the cell.

10. The device of claim 9, wherein the seal melts upon the occurrence of the predetermined condition.

11. The device of claim 9, wherein the electrode comprises excess positive electrode capacity.

12. The device of claim 9, further comprising a removable outer retaining band surrounding the housing.

13. An electrochemical device, comprising:

an electrode assembly comprising;

a plurality of elongated positive electrodes;

a plurality of elongated negative electrodes; and

a plurality of separation layers engagable with eachother to form a continuous separation barrier between each of the plurality of positive electrodes and the plurality of negative electrodes;

the plurality of layers positioned such that the positive electrodes, separation layers, and negative electrodes wound around a central axis thereby forming a coil of alternating electrode and separation layers such that the separation layer prevents direct contact between successive electrode layers, a first longitudinal edge of the positive electrode layer extends beyond a first longitudinal edge of the separation layer, and a first longitudinal edge of the negative electrode extends beyond a second longitudinal edge of the separation layer;

the separator tensioned across the electrode assembly and defines a cell width, the width of the electrodes extending beyond the width of the separator; and

a housing having a positive plate electrically coupled to the first longitudinal edge of the positive electrode and a negative plate electrically coupled to the first longitudinal edge of the negative electrode, wherein the electrode assembly is enclosed by the housing.

14. The device of claim 13, wherein the separator comprises a central portion having a first end and second end and a first protruding portion and second protruding portion the central portion being longer than the first and second protruding lengths, the first and second protruding portions extending from substantially the first and second ends respectively with a negative and positive electrodes partially disposed between the central portion and one of the protruding portions.

15. The device of claim 13, wherein each of the protruding portions of each of the plurality of separation layers overlaps the protruding portion of another separation layer.

16. The device of claim 15, wherein the separation layers are indexed such that position of the overlap of the separation layers varies substantially evenly across the cell width.