Methods and devices associated with bonding of solid-state lithium batteries
An example device includes a lithium-based battery having conductive battery contacts protruding from a surface of the battery, where a non-conductive portion of the surface of the battery separates the conductive battery contacts. The battery is a type that undergoes an expansion during charging in which the expansion of the lithium-based battery includes an outward bulging of the non-conductive portion of the battery surface. The device includes a substrate having conductive substrate contacts. The conductive battery contacts are electrically connected to the respective conductive substrate contact via a flexible electrically-conductive adhesive that physically separates the conductive battery contacts from the respective conductive substrate contacts and allows for relative movement therebetween caused by the expansion of the lithium-based battery.
1. A method comprising:
providing a lithium-based battery having a first battery surface and a second battery surface opposite the first battery surface, wherein the first battery surface has first and second conductive battery contacts protruding from the first battery surface, wherein the first and second conductive battery contacts are separated by a non-conductive portion of the first battery surface, and wherein the lithium-based battery is a type that undergoes an expansion during charging in which the expansion of the lithium-based battery includes an outward bulging of the non-conductive portion of the first battery surface;
providing a substrate having a substrate surface and first and second conductive substrate contacts protruding from the substrate surface, wherein the first and second conductive substrate contacts are separated by a non-conductive portion of the substrate surface; and
coupling the lithium-based battery to the substrate, wherein the coupling comprises:
rigidly coupling the second battery surface to the non-conductive portion of the substrate surface via a layer of a non-conductive adhesive;
electrically connecting the first conductive battery contact to the first conductive substrate contact via a first portion of a flexible electrically-conductive adhesive, wherein the first portion allows for relative movement between the first conductive battery contact and the first conductive substrate contact caused by the expansion of the lithium-based battery; and
electrically connecting the second conductive battery contact to the second conductive substrate contact via a second portion of a flexible electrically-conductive adhesive, wherein the second portion allows for relative movement between the second conductive battery contact and the second conductive substrate contact caused by the expansion of the lithium-based battery.
2. The method of claim 1 , wherein the lithium-based battery includes at least an anode layer and an electrolyte layer, and wherein the expansion during charging is caused at least in part by lithium accumulating between the anode layer and the electrolyte layer during charging.
3. The method of claim 1 , wherein the rigid non-conductive adhesive comprises an epoxy based adhesive.
4. The method of claim 1 , wherein the flexible electrically-conductive adhesive is an isotropically conductive adhesive material.
5. The method of claim 4 , wherein the isotropically conductive adhesive material comprises a polymeric material containing metallic particles.
6. The method of claim 5 , further comprising:
applying the isotropically conductive adhesive material with the polymeric material in an uncured state to (i) at least one of the first conductive battery contact or the first conductive substrate contact and (ii) at least one of the second conductive battery contact or the second conductive substrate contact; and
curing the polymeric material.
7. A device comprising:
a lithium-based battery having a first battery surface and a second battery surface opposite the first battery surface, wherein the first battery surface has first and second conductive battery contacts protruding from the first battery surface, wherein the first and second conductive battery contacts are separated by a non-conductive portion of the first battery surface, and wherein the lithium-based battery is a type that undergoes an expansion during charging in which the expansion of the lithium-based battery includes an outward bulging of the non-conductive portion of the first battery surface;
a substrate having a substrate surface and first and second conductive substrate contacts protruding from the substrate surface, wherein the first and second conductive substrate contacts are separated by a non-conductive portion of the substrate surface;
a non-conductive adhesive disposed between the second battery surface and the non-conductive portion of the substrate surface, wherein the non-conductive adhesive rigidly couples the second battery surface to the non-conductive portion of the substrate surface;
a first portion of a flexible electrically-conductive adhesive, wherein the first portion electrically connects the first conductive battery contact to the first conductive substrate contact and allows for relative movement therebetween caused by the expansion of the lithium-based battery; and
a second portion of the flexible electrically-conductive adhesive, wherein the second portion electrically connects the second conductive battery contact to the second conductive substrate contact and allow for relative movement therebetween caused by the expansion of the lithium-based battery.
8. The device of claim 7 , wherein the non-conductive adhesive comprises an epoxy based adhesive.
9. The device of claim 7 , wherein the lithium-based battery includes at least an anode layer and an electrolyte layer, and wherein the expansion during charging is caused at least in part by lithium accumulating between the anode layer and the electrolyte layer during charging.
10. The device of claim 7 , wherein the flexible electrically-conductive adhesive is an isotropically conductive material comprising a silicone-based polymer containing metallic particles.