Current interrupt for electrochemical cells
To counteract the potentially destructive effects of temperature increases in primary batteries during short circuit conditions, a current interrupt may be positioned within an anode conductive path. The current interrupt may comprise a thermoplastic substrate having a low glass transition temperature, and having a conductive coating thereon to form a portion of the anode conductive path. During a short circuit, the temperature within the battery increases above the glass transition temperature of the thermoplastic substrate, thereby causing the current interrupt to deform, thereby degrading the portion of the anode conductive path defined by the current interrupt, decreasing the amount of current flowing through the anode conductive path, and effectively limiting the temperature increase within the battery interior.
1. A electrochemical cell comprising:
a container having a positive terminal and a negative terminal cover;
a ring-shaped cathode positioned within the container and defining a hollow interior, wherein the cathode is in electrical connection with the positive terminal;
an anode positioned within the hollow interior of the cathode;
an anode conducting assembly electrically connecting the anode with the negative terminal cover, wherein the anode conducting assembly comprises:
an anode current collector; and
a current interrupt assembly secured to the anode current collector and electrically connecting the anode current collector with the negative terminal cover, wherein the current interrupt assembly comprises a thermoplastic pad having a conductive plating positioned between the anode current collector and the negative terminal cover; and
a separator positioned between the cathode and the anode.
2. The electrochemical cell of claim 1 , wherein the conductive plating has a thickness between about 1.5 microns and about 10 microns.
3. The electrochemical cell of claim 1 , wherein the thermoplastic pad comprises a thermoplastic material having a glass transition temperature of less than 150° C.
4. The electrochemical cell of claim 1 , wherein the thermoplastic pad comprises an ABS plastic.
5. The electrochemical cell of claim 1 , wherein the conductive plating comprises at least one of: copper or tin.
6. A conducting assembly for an electrochemical cell, wherein the conducting assembly is configured for conducting current along a conductive path from an electrode to a terminal of the electrochemical cell, wherein the conducting assembly comprises:
a current collector in contact with the electrode; and
a current interrupt secured onto the current collector, wherein the current interrupt is configured for conducting current from the current collector to the terminal of the electrochemical cell, wherein the current interrupt comprises:
a thermoplastic pad; and
a conductive plating layer on an exterior surface of the thermoplastic, wherein the conductive plating layer defines at least a portion of the conductive path.
7. The conducting assembly of claim 6 , wherein the thermoplastic pad comprises an ABS plastic.
8. The conducting assembly of claim 6 , wherein the conductive plating layer comprises at least one of copper or tin.
9. A method of manufacturing a primary electrochemical battery, the method comprising:
providing a battery container having a positive terminal and a negative terminal cover;
disposing a cathode within the container, wherein the cathode is in electrical connection with the positive terminal, and wherein the cathode defines a hollow interior;
disposing a separator along an interior wall of the hollow interior of the cathode;
filling the hollow interior of the cathode with an anode;
positioning an anode current collector within the anode; and
electrically connecting the anode current collector with the negative terminal cover via a current interrupt assembly secured to the anode current collector, wherein the current interrupt assembly comprises a thermoplastic pad having a conductive plating.
10. The method of claim 9 , further comprising steps for forming the current interrupt assembly by:
providing a thermoplastic disk as a substrate; and
plating the thermoplastic disk with a conductor.
11. The method of claim 10 , wherein the conductor comprises one of: copper or tin.
12. The electrochemical cell of claim 1 , wherein the current interrupt assembly is in contact with a lower surface of the negative terminal cover and an upper end of the anode current collector.
13. The electrochemical cell of claim 1 , wherein the conductive plating surrounds the thermoplastic pad.
14. The conducting assembly of claim 6 , wherein the conductive plating layer surrounds the thermoplastic pad.
15. The conducting assembly of claim 6 , wherein the current interrupt is in contact with an upper end of the current collector.
16. The method of claim 9 , wherein electrically connecting the anode current collector with the negative terminal cover comprises placing the current interrupt assembly between an upper end of the anode current collector and a lower surface of the negative terminal cover.
17. The method of claim 9 , wherein the conductive plating surrounds the thermoplastic pad.