Thermal and electrical management of battery packs
Provided are battery packs and interface modules for electrically interconnecting electrochemical cells in the packs and for providing heat distribution with the packs. An interface module interfaces one side of all electrochemical cells in a battery pack. The interface module may have a substantially planar shape such that the space occupied by the module in the battery pack is minimal. Most, if not all, conductive components of the interface module may be formed from the same sheet of metal. In some embodiments, the interface module includes multiple bus bars such that each bus bar interconnects two or more terminals of different electrochemical cells in the battery pack. Each bus bar may have a separate voltage sense lead extending from the bus bar to a connecting portion. The bus bars may be flexibly supported within the module. The interface module may also include multiple thermistors disposed on different bus bars.
1. A battery pack comprising:
a plurality of electrochemical cells, wherein each of the plurality of electrochemical cells comprises a first terminal and a second terminal; and
an interface module having a substantially planar shape;
wherein the interface module comprises two or more bus bars, voltage sense leads, and a base; wherein the voltage sense leads connect the two or more bus bars to the interface module; wherein the bus bars have a substantially planar shape;
wherein:
the electrochemical cells are arranged between two end frames;
the interface module is substantially orthogonal to the end frames;
each of the two or more bus bars comprises an electrically conductive material;
the base comprises an electrically insulating material and mechanically supports the two or more bus bars;
the two or more bus bars electrically interconnect the plurality of electrochemical cells within the battery pack; and
the thickness of the voltage sense leads and the thickness of the two or more bus bars is substantially the same;
each of the two or more bus bars forms a monolithic structure with the voltage sense leads; and
wherein the electrically insulating material of the base is thermally conductive with a thermal conductivity between about 2 W/m-K and 100 W/m-K.
2. The battery pack of claim 1 , wherein the first terminal and the second terminal of each of the plurality of electrochemical cells are disposed on a same side of each of the plurality of electrochemical cells facing the interface module.
3. The battery pack of claim 1 , wherein the interface module further comprises a connecting portion having multiple connecting leads, wherein each of the two or more bus bars has a separate electrical connection to one of the multiple connecting leads.
4. The battery pack of claim 3 , wherein each of the two or more bus bars is electrically connected to one of the multiple connecting leads using one of the voltage sense leads.
5. The battery pack of claim 4 , wherein the voltage sense leads are coplanar with the two or more bus bars.
6. The battery pack of claim 3 , further comprising a control module connected to the multiple connecting leads of the connecting portion and configured to control external electrical connections to each of the two or more bus bars.
7. The battery pack of claim 6 , wherein the control module is supported on an end frame of the battery pack and extends substantially normal to the interface module.
8. The battery pack of claim 3 , wherein the interface module further comprises a thermistor module having multiple thermistors positioned in different locations of the interface module, wherein each of the multiple thermistors has a separate electrical connection to one of the multiple connecting leads.
9. The battery pack of claim 8 , wherein each of the multiple thermistors is positioned on a different one of the two or more bus bars.
10. The battery pack of claim 1 , wherein the base comprises spacing members protruding in between the first terminal and the second terminal of each of the plurality of electrochemical cells.
11. The battery pack of claim 1 , further comprising a thermal control module thermally coupled to the interface module, wherein the thermal control module comprises a heat exchanger having one or more manifolds for transporting heat carrying fluid.
12. The battery pack of claim 1 , wherein the two or more bus bars are electrically connected to the first terminal and the second terminal of each of the plurality of electrochemical cells using flexible connectors,
wherein the flexible connectors allow the two or more bus bars to move with respect to the first terminal and the second terminal of each of the plurality of electrochemical cells while maintaining the two or more bus bars electrically connected to the first terminal and the second terminal of each of the plurality of electrochemical cells.
13. The battery pack of claim 1 , wherein the base is flexible and allows the two or more bus bars to move with respect to each other during operation of the battery pack.
14. The battery pack of claim 1 , wherein the interface module has a thickness of less than 10 millimeters.
15. The battery pack of claim 1 , wherein the interface module is operable as a cover of the battery pack.
16. The battery pack of claim 15 , wherein a surface of the interface module facing away from the plurality of electrochemical cells is substantially insulating.
17. The battery pack of claim 1 , wherein the interface module is conformal to top surfaces of the plurality of electrochemical cells.
18. The battery pack of claim 1 , wherein the two or more bus bars are electrically connected to the first terminal and the second terminal of each of the plurality of electrochemical cells such that any of the two or more bus bars does not electrically short any of the plurality of electrochemical cells.
19. The battery pack of claim 1 , wherein each of the two or more bus bars is electrically connected to two terminals of different cells of the plurality of electrochemical cells thereby electrically interconnecting the plurality of electrochemical cells within the battery pack.
20. The battery pack of claim 19 , wherein each of the two or more bus bars is electrically connected to (i) the first terminal of one cell of the plurality of electrochemical cells and to the first terminal of another cell of the plurality of electrochemical cells, to (ii) the second terminal of one cell of the plurality of electrochemical cells and to the second terminal of another cell of the plurality of electrochemical cells, or to (iii) the first terminal of one cell of the plurality of electrochemical cells and to the second terminal of another cell of the plurality of electrochemical cells.
21. The battery pack of claim 1 , wherein the battery pack further comprises a thermal control module thermally coupled to the interface module.
22. The battery pack of claim 1 , wherein the battery pack further comprises a thermal control module in contact with the interface module.
23. The battery pack of claim 22 , wherein the thermal control module comprises a heat exchanger.