Electrochemical double layer capacitor having carbon powder electrodes

• US 20030086238A1
• Filed: 11/02/2001
• Published: 05/08/2003
• Est. Priority Date: 11/02/2001
• Status: Active Grant

• Current Assignee: UCAP Power, Inc.
• Original Assignee: Maxwell Technologies Incorporated (Tesla Inc.)
• Inventors: Chaney, Earl, Nanjundiah, Chenniah, Dispennette, John M., Bendale, Priya, Malay, Manuel R.
• Granted Patent: US 6,643,119 B2
• Time in Patent Office: Days
• US Class Current: 361/502
• CPC Class Codes: H01G 11/28 arranged or disposed on a current collector; Layers or phases between electrodes and current collectors, e.g. adhesives
• CPC Class Codes: H01G 11/32 Carbon-based
• CPC Class Codes: H01G 11/72 specially adapted for integration in multiple or stacked hybrid or EDL capacitors
• CPC Class Codes: H01G 11/74 Terminals, e.g. extensions of current collectors
• CPC Class Codes: H01G 11/82 Fixing or assembling a capacitive element in a housing, e.g. mounting electrodes, current collectors or terminals in containers or encapsulations
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

A method of making an electrode structure, the electrode structure and a double layer capacitor including the electrode structure, the method comprising the steps of: forming a plurality of electrodes, each having a current collector plate, a primary coating formed on each side of the collector plate, the primary coating including conducting carbon powder and a binder, and a secondary coating formed on each primary coating, the secondary coating including activated carbon powder, a solvent and a binder; positioning a respective separator between each electrodes while stacking the electrodes such that the respective separator is juxtaposed against respective secondary coatings of adjacent electrodes that electrically insulates the adjacent electrodes, whereby forming an electrode stack; and rolling the electrode stack into a cylindrical electrode structure.

Claims

1. A method of making an electrode structure for use in a double layer capacitor, comprising the steps of:

forming a plurality of electrodes, each of the plurality of electrodes comprising;

a current collector plate;

a primary coating formed on a portion of each side of the current collector plate, the primary coating including conducting carbon powder and a binder; and

a secondary coating formed on each primary coating, the secondary coating including activated carbon powder, a solvent and a binder;

positioning a respective separator between each of the plurality of electrodes while stacking the plurality of electrodes on top of each other such that the respective separator is juxtaposed against respective secondary coatings of adjacent ones of the plurality of electrodes, wherein the respective separator electrically insulates the adjacent ones of the plurality of electrodes from each other, whereby forming a stack of the plurality of electrodes with a respective separator positioned in between respective ones of the plurality of electrodes; and

rolling the electrode stack starting at one end of the electrode stack into a cylindrical structure.

2. The method of claim 1 further comprising electrically coupling together a first set of respective ones of a portion of each current collector plate that do not have the respective primary coating formed thereon to form a first terminal.

3. The method of claim 2 further comprising electrically coupling together a second set of respective ones of the portion of each current collector plate that do not have the respective primary coating formed thereon to form a second terminal.

4. The method of claim 3 further comprising inserting the rolled electrode stack into a capacitor can;

coupling the first terminal to a first capacitor terminal of the capacitor can;

coupling the second terminal to a second capacitor terminal of the capacitor can;

saturating the rolled electrode stack in a prescribed electrolytic solution; and

sealing the rolled electrode stack and the prescribed electrolytic solution within the capacitor can.

5. The method of claim 1 wherein the positioning while stacking steps are performed such that upon rolling the electrode stack, a portion of each current collector plate that does not have a respective primary coating formed thereon extends from a respective end of the rolled electrode stack.

6. The method of claim 5 wherein the positioning while stacking steps are performed such that upon rolling the electrode stack, the portion of each current collector plate that does not have the respective primary coating formed thereon extends from an opposite end of the rolled electrode stack as extends the portion of each adjacent current collector in the electrode stack that does not have the respective primary coating formed thereon.

7. The method of claim 6 further comprising smearing together portions of the current collector plates extending from each end of the electrode stack into electrical contact with each other.

8. The method of claim 7 further comprising applying a conductive coating to a portion of the current collector plates smeared together at each end of the electrode stack, each conductive coating adapted to be coupled to a respective capacitor terminal.

9. A method of making an electrode structure for use in a double layer capacitor, comprising the steps of:

forming a plurality of electrodes, each of the plurality of electrodes comprising;

a current collector plate having a length and a width and a thickness;

a primary coating formed on a portion of each side of the current collector plate, the portion covering an area extending the full length of the current collector plate and extending a portion of the width of the current collector plate, the primary coating including conducting carbon powder and a binder; and

a secondary coating formed on each primary coating, the secondary coating including activated carbon powder, a solvent and a binder;

positioning a respective separator between each of the plurality of electrodes while stacking the plurality of electrodes on top of each other such that the respective separator is juxtaposed against respective secondary coatings of adjacent ones of the plurality of electrodes, wherein the respective separator electrically insulates the adjacent ones of the plurality of electrodes from each other, whereby forming a stack of the plurality of electrodes with a respective separator positioned in between respective ones of the plurality of electrodes, the electrode stack having a stack length and a stack width; and

rolling the electrode stack starting at one end of the electrode stack along the stack length into a cylindrical structure.

10. The method of claim 9 further comprising electrically coupling together a first set of respective ones of the portion of each current collector plate that do not have the respective primary coating formed thereon to form a first terminal.

11. The method of claim 10 further comprising electrically coupling together a second set of respective ones of the portions of each of the plurality of electrodes that do not have the respective primary coating formed thereon to form a second terminal.

12. The method of claim 9 wherein the positioning while stacking steps are performed such that upon rolling the electrode stack, a portion of each current collector plate that does not have a respective primary coating formed thereon extends from a respective end of the rolled electrode stack.

13. An electrode structure for use in a double layer capacitor comprising:

a rolled electrode stack comprising;

a plurality of electrodes, each of the plurality of electrodes comprising;

a current collector foil;

a primary coating formed on a portion of each side of the current collector foil, the primary coating including conducting carbon powder and a binder; and

a secondary coating formed on each primary coating, the secondary coating including activated carbon powder, a solvent and a binder;

a respective separator positioned between each of the plurality of electrodes in a stack such that the respective separator is juxtaposed against respective secondary coatings of adjacent ones of the plurality of electrodes, wherein the respective separator electrically insulates the adjacent ones of the plurality of electrodes from each other,

wherein the electrode stack is rolled starting at one end of the electrode stack into a cylindrical structure to form the rolled electrode stack.

14. The structure of claim 13 wherein a first set of respective ones of a portion of each current collector foil that do not have the respective primary coating formed thereon are electrically coupled together to form a first terminal.

15. The structure of claim 14 wherein a second set of respective ones of the portion of each current collector foil that do not have the respective primary coating formed thereon are electrically coupled together to form a second terminal.

16. The structure of claim 13 wherein a portion of each current collector foil that does not have a respective primary coating formed thereon extends from a respective end of the rolled electrode stack.

17. The structure of claim 16 wherein the portion of each current collector foil that does not have the respective primary coating formed thereon extends from an opposite end of the rolled electrode stack as extends the portion of each adjacent current collector foil in the rolled electrode stack that does not have the respective primary coating formed thereon.

18. The structure of claim 17 wherein portions of the current collector foils extending from each end of the rolled electrode stack are smeared together into electrical contact with each other.

19. The structure of claim 18 further comprising a conductive coating applied to a portion of the current collector foils smeared together at each end of the rolled electrode stack, each conductive coating adapted to be coupled to a respective capacitor terminal.

20. A double layer capacitor comprising:

a capacitor can having a first terminal and a second terminal;

a rolled electrode structure contained within the capacitor can, the rolled electrode structure comprising;

a plurality of electrodes, each of the plurality of electrodes comprising;

a current collector foil;

a primary coating formed on a portion of each side of the current collector foil, the primary coating including conducting carbon powder and a binder; and

a secondary coating formed on each primary coating, the secondary coating including activated carbon powder, a solvent and a binder;

a respective separator positioned between each of the plurality of electrodes in a stack such that the respective separator is juxtaposed against respective secondary coatings of adjacent ones of the plurality of electrodes, wherein the respective separator electrically insulates the adjacent ones of the plurality of electrodes from each other, wherein the electrode stack is rolled starting at one end of the electrode stack into a cylindrical structure to form the rolled electrode structure; and

an electrolytic solution contained within the capacitor can.