Method of construction of electrochemical cell device using capillary tubing and optional permselective polymers

• US 6,174,337 B1
• Filed: 12/14/1999
• Issued: 01/16/2001
• Est. Priority Date: 01/06/1997
• Status: Expired due to Term

• Current Assignee: Ultracap Technologies Corp.
• Original Assignee: Pinnacle Research Institute, Inc.
• Inventors: Keenan, Richard L.
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): NGUYEN, HA T
• Application Number:
  US09/461,628
• Time in Patent Office: 399 Days
• Field of Search: 29/250-- 2, 296/231-623, 296/234-623, 427/80, 361/502-504, 361/518, 361/522, 361/541
• US Class Current: 29/25.03
• CPC Class Codes: H01G 11/12 Stacked hybrid or EDL capacitors
• CPC Class Codes: H01G 11/14 Arrangements or processes for adjusting or protecting hybrid or EDL capacitors emergency protective circuit arrangements specially adapted for capacitors, and effecting automatic switching in the event of an undesired change from normal working conditions H02H7/16; emergency protective circuit arrangements for limiting excess current or voltages without disconnection H02H9/00
• CPC Class Codes: H01G 11/20 Reformation or processes for removal of impurities, e.g. scavenging
• CPC Class Codes: H01G 11/52 Separators
• CPC Class Codes: H01G 11/80 Gaskets; Sealings
• CPC Class Codes: H01G 11/84 Processes for the manufacture of hybrid or EDL capacitors, or components thereof
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors
• CPC Class Codes: Y10T 29/49108 Electric battery cell making
• CPC Class Codes: Y10T 29/4911 including sealing

Abstract

The method comprises forming a dry preunit including a stack of cells. Each cell is formed by placing sequentially a conductive support sheet coated on one or both sides with a porous conductive material except at the perimeter edge surfaces, an ion permeable or semi-permeable space separator, a gasket, at least one hollow capillary tube having a melting point higher than the gasket material. Upon heating the gasket material flows, adheres to, and seals the edges of the stack creating a solid integral stack of layers of alternating electrically conductive sheet coated with a porous electrically conducting material and a separator. The gasket material creates a continuous integral external polymer enclosure having hollow capillary tubes. After an electrolyte is introduced into the preunit, the capillary tubes are sealed.

Claims

1. An improved method to produce a dry preunit of an electrical storage device having a hollow capillary port for storage of electrical charge in a condition to have the internal electrode surfaces contacted with a non-aqueous or aqueous electrolyte to store electrical charge in a double layer manner, which method comprises:

(a) preparing a thin in thickness substantially flat sheet of electrically conducting support material coated on each flat side with the same or different thin layer of porous electrically conducting material having a high surface area, with the provisio that on both flat sides of the electrically conducting support material wherein the perimeter edge surfaces are devoid of porous electrically conducting material;

(b) creating an ion permeable or semipermeable space separator stable to the aqueous or non-aqueous electrolyte, the space separator is obtained by;

(i) depositing substantially uniform in height groups of electrically insulating microprotrusions, on the surface of at least one side of the thin layer of porous electrically conducting material,

(ii) placing a thin precut ion permeable or semipermeable separator on one surface of the porous electrically conducting material, or

(iii) creating an ion permeable or semipermeable thin layer on the surface of at least one side of the porous electrically conducting material, or

(iv) creating an air space as separator;

(c) contacting the perimeter edge surface of one or both sides of the thin sheet of step (a) with one or more layers of synthetic organic polymer as a gasket material selected from the group consisting of a thermoplastic and an elastomeric polymer;

(d) placing on or within the gasket material and optionally across the thin sheet at least one polymer coated hollow capillary tube of a different material, wherein the hollow capillary tube has a melting point (T_m) greater than the gasket material and permanently adheres to the gasket material under the processing conditions;

(e) producing a repeating layered stack of the thin sheet coated with porous electrically conducting material and a separator produced in step (b), therefore forming a plurality of cells;

(f) heating the stack produced in step (e) at a temperature and applied pressure effective to cause the gasket material to flow, to adhere to, and to seal the edges of the stack creating a solid integral stack of layers of alternating electrically conductive sheet coated with porous electrically conducting material and the ion permeable separator, such that the gasket material creates a continuous integral external polymer enclosure with the proviso that the hollow capillary tube provides a pathway to introduce the electrolyte into the preunit;

(g) cooling the solid integral stack of step (f) optionally in an inert gas under slight pressure, wherein the integral stack is sealed, except for the hollow capillary tube by heating the integral stack to between 5° and

100°

C., above the T_m of the gasket material;

(h) sealing the at least one hollow capillary tube after the electrolyte is introduced into the preunit.

2. The method of claim 1 wherein:

the capillary tube comprises a glass coated with a polymer selected from the group consisting of polyimide, polyurethane, polyepoxide, and polysilicone.

3. The method of claim 2 wherein:

the capillary tube has an internal diameter of between about 5 and 50 micron and an external diameter of between about 80 and 200 micron.

4. A method of producing an electrical energy storage device, which method comprises:

(h) preweighting the preunit device obtained in claim 1;

(i) placing the entire device formed in claim 1 in a pre weighted aqueous or non-aqueous electrolyte;

(j) subjecting the device to a vacuum of at least 0.01 mm of mercury;

(k) releasing the vacuum whereby the electrolyte is backfilled into the cells;

(l) repeating steps (j) and (k) as needed to completely fill the cells of the device;

(m) sealing the at least one capillary tube, thereby creating the electrical storage device, and

(n) optionally weighing the filled electrical storage device and the remaining external aqueous or non-aqueous electrolyte to determine the electrolyte uptake.

5. The method of claim 4 which further includes:

(o) encasing the electrical storage device of claim 4 with a metal covering or a polymeric material to improve the long term effective life of the device.

6. The method of claim 3 wherein:

the capillary tube has a diameter of about 10 micron and an external diameter of about 100 micron.

7. The method of claim 1 wherein:

the porous electrically conducting material is selected from the group consisting of transition metal oxides, nitrides, carbides, borides, oxynitrides, and combinations thereof.

8. The method of claim 6 wherein:

the porous electrically conducting material is selected from transition metal oxides and combinations thereof.

9. The method of claim 8 wherein:

the transition metal oxides are selected from ruthenium oxide, tantalum oxide and combinations thereof.

10. The method of claim 1 wherein:

in step (a) the support material is selected from titanium, niobium or tantalum, and the porous electrically conducting material is selected from ruthenium oxide, tantalum oxide or combinations thereof;

in step (b) a precut permeable separator is used;

in step (c) the synthetic organic polymer is selected from high density polyethylene or high density polypropylene;

in step (d), the capillary tube is a polyimide coated silica capillary tube, optionally a gas selectively permeable venting body is incorporated into the edge of each cell.

11. An improved method to produce a dry preunit of an electrical storage device, which method comprises:

(A) in the improved method described in claim 1 step (d) also includes (d′

) means for selectively venting a gas generated in the package without exposure of the inside of the package to the ambient environment which means comprise at least one gas selectively permeable body at the edge of the cell between the cell and ambient environment, which body has a relatively high permeability of a gas generated within the device during the operation of the component and a relatively low permeability to at least one desired fluid within the cell, and thereby avoid premature failure of the device.

12. The method of claim 11 wherein:

the selectively permeable body is selected from the group consisting of silicone rubber, polypropylene, natural rubber, butyl rubber, tetrofluoroethylene, polyethylene or combinations thereof.

13. The method of claim 12 wherein:

the selectively permeable body is selected from high density polyethylene or polypropylene.

14. The method of claim 11 wherein:

the porous electrically conducting material having a high surface area is selected from the group consisting of transition metal oxides, carbides, nitrides, borides, oxynitrides and combinations thereof.

15. The method of claim 14 wherein:

the porous electrically conducting material is selected from transition metal oxides and combinations thereof.