Micro-channel cooling fin design based on an equivalent temperature gradient

1. A micro-channel cooling fin for a battery module, the micro-channel cooling fin comprising a metal plate assembly defining a plurality of cooling channels therein, the metal plate assembly including:

an inlet section for introducing a liquid coolant into the plurality of cooling channels; and

an outlet section from which the coolant exits the plurality of cooling channels, a first subset of cooling channels providing a first mass flow rate of the coolant to a first fin region of the metal plate assembly and a second subset of the cooling channels providing a second mass flow rate of the coolant to a second fin region of the metal plate assembly, the metal plate assembly positionable between battery cells in a battery module such that the first fin region is proximate to a first battery region and the second fin region is proximate to a second battery region where the first battery region has higher temperature during battery operation than the second battery region when the battery module is not cooled.

2. The cooling fin of claim 1 wherein each channel of the first subset provides a higher mass flow rate than each channel of the second subset when the coolant is flowed through the plurality of cooling channels.

3. The cooling fin of claim 2 wherein the first subset of cooling channels is closer to an anode tab and cathode tab of the battery cell.

4. The cooling fin of claim 1 wherein each channel of the first subset provides a lower flow resistance than each channel of the second subset.

5. The cooling fin of claim 1 wherein each channel of the first subset has a higher average cross sectional area than each channel of the second subset.

6. The cooling fin of claim 1 wherein the channels of the first subset have a smaller average separation than the channel of the second subset.

7. The cooling fin of claim 1 wherein the metal plate assembly has a first end and a second end, a first side and a second side such that the inlet section is positioned at the first end and the first side and the outlet section is positioned at the first end and the second side.

8. The cooling fin of claim 7 wherein each cooling channel has a first channel region with a first cross sectional area from 0.5 to about 0.8 mm 2 and a second channel region with a second cross sectional area from 0.5 to about 0.8 mm 2 , the second channel region being in fluid communication with the first channel region which is in fluid communication with the inlet section.

9. The cooling fin of claim 8 wherein each cooling channel includes a U-shaped channel section that is in fluid communication with the second channel region.

10. The cooling fin of claim 9 wherein the U-shaped channel section has a third cross sectional area from about 1.0 to about 1.8 mm 2 .

11. The cooling fin of claim 10 wherein the first channel region has a trapezoidal cross section.

12. The cooling fin of claim 10 wherein the second channel region and the U-shaped channel section each independently have a hexagonal cross section.

13. The cooling fin of claim 1 wherein the liquid coolant for each channel having an outlet temperature and an inlet temperature such that the outlet temperature minus the inlet temperature for all the micro channels is within 5° C.

14. A micro-channel cooling fin for a battery module, the micro-channel cooling fin comprising a metal plate assembly defining a plurality of cooling channels therein, the metal plate assembly including:

an inlet section for introducing a liquid coolant into the plurality of cooling channels; and

an outlet section from which the coolant exits the plurality of cooling channels, the liquid coolant for each channel having an output temperature and an input temperature such that the output temperature minus the input temperature for all the micro channels is within 5° C.

15. A battery module comprising

a plurality of battery cells;

a plurality of cooling fins interposed between battery cells in the plurality of battery cells; and

a liquid coolant system for circulating liquid coolant through the cooling fins;

wherein each cooling fin comprises a metal plate assembly defining a plurality of cooling channels therein, the metal plate assembly including:

an inlet section that receives the coolant from the liquid coolant system and directs the coolant into the plurality of cooling channels; and

an outlet section from which the coolant exits the plurality of cooling channels, a first subset of the cooling channels providing a first mass flow rate of the coolant to a first fin region of the metal plate assembly and a second subset of the cooling channels providing a second mass flow rate of the coolant to a second fin region of the metal plate assembly, the metal plate assembly positionable adjacent to a battery cell such that the first fin region is proximate to a first battery region and the second fin region is proximate to a second battery region where the first battery region has higher temperature during battery operation than the second battery region when the battery module is not cooled.