Low impedance layered battery apparatus and method for making the same
View Patent ↗An electro-chemical storage device is described, and a method for making the same. In some aspects, a guidewire is co-wound with sheet or ribbon-like electrode materials so that contact is made between the guidewire and collector extensions of the electrode materials thereby forming an endcap with low impedance and high thermal sinking capabilities. In one embodiment, the storage device includes a negative electrode sheet have an edge which is substantially free of electrode active material, a positive electrode sheet have an edge which is substantially free of electrode active material, a first conductive guidewire disposed adjacent to the edge of the negative electrode sheet which is substantially free of electrode active material, and a second conductive guidewire disposed adjacent to the edge of the positive electrode sheet which is substantially free of electrode active material. The first conductive guidewire and the edge of the negative electrode sheet which is substantially free of electrode active material define a first electrode endcap and the second conductive guidewire and the edge of the positive electrode sheet which is substantially free of electrode active material define a second electrode endcap. The electrode endcaps are coupled to terminals of the storage device, which are capable of being connected to the terminals of an external circuit.
1. An electrochemical storage device, comprising:
a coiled assembly comprising a negative electrode sheet, a positive electrode sheet and a separator sheet disposed between the negative and positive electrode sheets, at least one of the positive and negative electrode sheets having an edge which is substantially free of electrode active material; and
a conductive guidewire disposed adjacent to an edge of an electrode sheet which is substantially free of electrode active material, wherein the conductive guidewire and the edge which is substantially free of electrode active material are wound to form an electrode endcap.
2. The device of claim 1 , wherein the thickness of the guidewire is substantially equal to the radial spacing which exists between adjacent portions of the edge of the electrode sheet which is substantially free of electrode active material.
3. The device of claim 1 , wherein a physical dimension of the guidewire is selected to provide a selected thermal heat capacity.
4. The device of claim 1 , wherein one of the electrode sheets comprise a current collector sheet having layers of active material disposed on portions of opposing surfaces of the current collector sheet.
5. The device of claim 1 , wherein,
the negative electrode sheet has an edge which is substantially free of electrode active material;
the positive electrode sheet has an edge which is substantially free of electrode active material;
the guidewire is in the form of a first conductive guidewire disposed adjacent to the edge of the negative electrode sheet which is substantially free of electrode active material, wherein the first conductive guidewire and the edge of the negative electrode sheet which is substantially free of electrode active material define the electrode endcap as a first electrode endcap; and
a second conductive guidewire is disposed adjacent to the edge of the positive electrode sheet which is substantially free of electrode active material, wherein the second conductive guidewire and the edge of the positive electrode sheet which is substantially free of electrode active material define a second electrode endcap.
6. The device of claim 5 , wherein the first electrode endcap and the second electrode endcap are disposed on opposite ends of the coiled assembly.
7. The device of claim 5 , wherein the first electrode endcap defines a cathode endcap and the second electrode endcap defines an anode endcap.
8. The device of claim 7 , further comprising:
a housing and a cover, the housing having a conductive portion and the cover having a conductive terminal; and
wherein the cathode endcap is electrically coupled to the conductive terminal of the cover and the anode endcap is electrically coupled to the conductive portion of the housing.
9. The device of claim 8 , further comprising a flexible conductive member that electrically couples the cathode endcap to the cover.
10. The device of claim 7 , further comprising:
a housing and a cover, the housing having a conductive portion and the cover having a conductive terminal; and
wherein the anode endcap is electrically coupled to the conductive terminal of the cover and the cathode endcap is electrically coupled to the conductive portion of the housing.
11. The device of claim 10 , further comprising a flexible conductive member that electrically couples the anode endcap to the cover.
12. The device of claim 5 , wherein the negative electrode sheet and the first conductive guidewire are both comprised of aluminum and the positive electrode sheet and the second conductive guidewire are both comprised of copper.
13. The device of claim 1 , further comprising a weld disposed on a portion of a face of the electrode endcap.
14. The device of claim 13 , wherein the weld is formed via laser welding.
15. The device of claim 13 , wherein the weld forms an electrical connection through successive windings of the conductive guidewire and the edge of the electrode sheet that define the electrode endcap.
16. The device of claim 13 , wherein the weld is disposed radially on the face of the electrode endcap.
17. The device of claim 1 , wherein the negative electrode sheet, positive electrode sheet, separator sheet and conductive guidewire are wound around a common axis to form substantially concentric windings having substantially cylindrical profiles.
18. The device of claim 1 , wherein the negative electrode sheet, positive electrode sheet, separator sheet and conductive guidewire are wound around a common axis to form substantially concentric windings having substantially prismatic profiles.
19. The device of claim 1 , wherein the electrode endcap further includes fluid passageways.
20. A battery pack device, comprising:
at least one assembly comprising at least two electrically-complementary electrode sheets having a separator sheet disposed between the two electrically-complementary sheets, wherein at least one of the electrode sheets has an edge substantially free of electrode active material; and
the at least one assembly also comprising a conductive guidewire disposed adjacent to an edge of an electrode sheet which is substantially free of electrode active material, wherein the conductive guidewire and the edge which is substantially free of electrode active material are wound to form an endcap for connection with an electrode terminal.
21. The device of claim 20 , wherein a first assembly and a second assembly are electrically connected in series.
22. The device of claim 20 , wherein a first assembly and a second assembly are electrically connected in parallel.
23. The device of claim 20 , wherein the thickness of the guidewire is substantially equal to the radial spacing which exists between adjacent portions of the edge of the electrode sheet which is substantially free of electrode active material.