Multilayered flexible battery interconnects and methods of fabricating thereof

Abstract

Provided are multilayered flexible battery interconnects for interconnecting batteries in battery packs and methods of fabricating thereof. A multilayered flexible battery interconnect comprises insulating layers and two conductive layers, stacked together and positioned between the insulating layers. One conductive layer is thicker than the other. The thinner conductive layer comprises flexible tabs for connecting to batteries and, in some examples, comprises voltage sense traces. The smaller thickness of these flexible tabs ensures welding quality and allows using less energy during welding. The battery cell contacts, to which these flexible tabs are welded, can be significantly thicker. Furthermore, the smaller thickness enables fusible link integration into flexible tabs. At the same time, the two conductive layers collectively conduct current within the interconnect, with the thicker layer enhancing the overall current-carrying capacity. The two conductive layers can be welded together to ensure electric connections and mechanical support.

What is claimed is: 
     
         1 . A multilayered flexible battery interconnect for interconnecting batteries in a battery pack, the multilayered flexible battery interconnect comprising:
 a first insulating layer;   a second insulating layer;   a first conductive layer, disposed between the first insulating layer and the second insulating layer and directly interfacing the first insulating layer; and   a second conductive layer, disposed between and directly interfacing each of the first conductive layer and the second insulating layer, wherein:   the first conductive layer is thicker than the second conductive layer, and   the second conductive layer comprises a plurality of flexible tabs extending past the first conductive layer for connecting to the batteries.   
     
     
         2 . The multilayered flexible battery interconnect of  claim 1 , wherein the first conductive layer is at least twice thicker than the second conductive layer. 
     
     
         3 . The multilayered flexible battery interconnect of  claim 1 , wherein:
 the first conductive layer has a thickness of at least 300 micrometers; and   the second conductive layer has a thickness of less than 150 micrometers.   
     
     
         4 . The multilayered flexible battery interconnect of  claim 1 , wherein both the first conductive layer and the second conductive layer are formed from aluminum. 
     
     
         5 . The multilayered flexible battery interconnect of  claim 1 , wherein the first conductive layer and the second conductive layer are formed from different materials. 
     
     
         6 . The multilayered flexible battery interconnect of  claim 1 , wherein the first conductive layer and the second conductive layer are welded together at multiple welded locations, separated from each other. 
     
     
         7 . The multilayered flexible battery interconnect of  claim 6 , wherein:
 the second insulating layer comprises welding openings; and   each of the multiple welded locations is positioned within one of the welding openings.   
     
     
         8 . The multilayered flexible battery interconnect of  claim 1 , wherein:
 the first conductive layer has a uniform thickness throughout an entire boundary of the first conductive layer; and   the second conductive layer has a uniform thickness throughout an entire boundary of the second conductive layer.   
     
     
         9 . The multilayered flexible battery interconnect of  claim 1 , wherein:
 the plurality of flexible tabs comprises a first tab set extending in a first direction; and   the plurality of flexible tabs comprises a second tab set extending in a second direction, opposite to the first direction.   
     
     
         10 . The multilayered flexible battery interconnect of  claim 9 , wherein:
 any two adjacent tabs in the first tab set are spaced apart by a battery pitch of the battery pack; and   any two adjacent tabs in the second tab set are spaced apart by the battery pitch of the battery pack.   
     
     
         11 . The multilayered flexible battery interconnect of  claim 10 , wherein:
 each the plurality of flexible tabs comprises a contact pad and a fusible link, connecting and supporting the contact pad relative to a remaining part of the second conductive layer; and   the contact pad is configured to connect to a center contact of one of the batteries.   
     
     
         12 . The multilayered flexible battery interconnect of  claim 11 , wherein:
 the second insulating layer comprises a contact opening; and   the fusible link and a majority of the contact pad protrude into the contact opening.   
     
     
         13 . The multilayered flexible battery interconnect of  claim 12 , wherein:
 the second insulating layer comprises a support tab, at least partially defining the contact opening; and   a portion of the contact pad is adhered to the support tab.   
     
     
         14 . The multilayered flexible battery interconnect of  claim 13 , wherein:
 the second insulating layer comprises a flexibility slit, extending along an interface between the support tab and a remaining portion of the second insulating layer.   
     
     
         15 . The multilayered flexible battery interconnect of  claim 9 , wherein:
 any two adjacent tabs in the first tab set are spaced apart by a battery pitch or a double of the battery pitch of the battery pack; and   any two adjacent tabs in the second tab set are spaced apart by a battery pitch or a double of the battery pitch of the battery pack.   
     
     
         16 . The multilayered flexible battery interconnect of  claim 15 , wherein:
 each tab in the first tab set and the second tab set comprises a contact pad and a flexible neck, connecting and supporting the contact pad relative to a remaining part of the tab; and   the contact pad is configured to simultaneously connect to edge contacts of two adjacent ones of the batteries.   
     
     
         17 . The multilayered flexible battery interconnect of  claim 16 , wherein:
 the second insulating layer comprises a contact opening; and   the flexible neck and a majority of the contact pad protrude into the contact opening.   
     
     
         18 . The multilayered flexible battery interconnect of  claim 17 , wherein:
 the second insulating layer comprises a support tab, at least partially defining the contact opening; and   a portion of the contact pad adheres to the support tab.   
     
     
         19 . The multilayered flexible battery interconnect of  claim 18 , wherein:
 the second insulating layer comprises a flexibility slit, extending along an interface between the support tab and a remaining portion of the second insulating layer.   
     
     
         20 . The multilayered flexible battery interconnect of  claim 1 , wherein the first insulating layer and the second insulating layer directly adhere to each other forming a boundary around portions of the first conductive layer and the second conductive layer.