Electrochemical double layer capacitor having carbon powder electrodes

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;
• wherein a first set of the plurality of electrodes comprises a respective current collector foil having portions without the primary coating formed thereon that extend from an end of the rolled structure and a second set of the plurality of electrodes comprises another respective current collector foil having portions without the primary coating formed thereon that extend from another end of the rolled structure;
• 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;
• 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.

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

• 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 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;
• a respective separator positioned between each of the plurality of electrodes wherein the respective separator is interposed between 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, thereby forming an electrode stack 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
• wherein a first set of the plurality of electrodes comprise respective current collector plates having a portion without the primary coating formed thereon that extends from an end of the rolled structure and a second set of the plurality of electrodes comprise respective current collector plates having a portion without the primary coating formed thereon that extends from another end of the rolled structure to form the electrode structure wherein the stack width is greater than the width;
• wherein the electrode stack is rolled starting at one end of the electrode stack along the stack length into a rolled structure.

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;
• and
• a layer comprising activated carbon electrically coupled to the current collector foil;
• wherein a first set of the plurality of electrodes comprises current collector foils extending from one end of the rolled electrode stack and a second set of the plurality of electrodes comprises current collector foils that extend from another end of the rolled electrode stack;
• wherein respective portions of the current collector foils in the first and second sets of the plurality of electrodes extending from the ends of the rolled electrode stack are smeared together into electrical contact with each other;
• a respective separator positioned between each of the plurality of electrodes in a stack such that the respective separator is juxtaposed against respective activated carbon layers 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.