Battery cell thermal regulation system
A thermal normalization system for battery cells is described. The thermal normalization system normalizes temperatures across battery cells to reduce temperature gradients and hot zones within battery cells to improve performance and lifespan. The thermal normalization system includes parallel heat transfer paths for heat from cells, including a first path through an end of the cells in contact with a cooling element, such as a cold plate, and a second path through a heat bridge that couples a portion of the cell remote from the cooling element to the cooling element along a path thermally isolated from the first end of the cells.
1 . A battery cell comprising:
a body having a first end and a second end and extending a first length from the first end to the second end, wherein:
the second end of the body is configured to be placed adjacent a cooling plate of a battery pack,
the first length comprises a second length from the second end towards the first end and a third length from the second length toward the first end, the second length and the third length each being less than the first length,
the body comprises a first region and a second region,
the first region is associated with the third length and proximate the first end, and
the second region is associated with the second length and proximate the second end;
an electrical connection at the first end of the body; and
an insulator disposed on an outer surface of the body adjacent the second end, wherein:
the insulator extends the second length from the second end towards the first end, and
the insulator is associated with the second region of the body.
2 . The battery cell of claim 1 , wherein the insulator comprises a hollow shell forming a vacuum insulation layer around the body.
3 . The battery cell of claim 1 , further comprising a thermal conductor coupled to the body adjacent the first end, the thermal conductor extending along an outer surface of the insulator to the second end of the body.
4 . The battery cell of claim 3 , wherein the thermal conductor contacts the body along the third length from the first end to the insulator.
5 . The battery cell of claim 3 , wherein the thermal conductor comprises a pyrolytic graphite sheet.
6 . The battery cell of claim 5 , further comprising a clamp surrounding the thermal conductor at the first end of the body, the clamp configured to secure the thermal conductor to the body.
7 . The battery cell of claim 3 , wherein the thermal conductor abuts the outer surface of the body at the first end and at least partially surrounds the electrical connection.
8 . The battery cell of claim 1 , further comprising a second insulator positioned at the second end and configured to resist heat flow to the cooling plate from the second end of the battery cell.
9 . The battery cell of claim 1 , wherein the insulator has a first thickness adjacent the second end of the body and a second thickness at an opposite end of the insulator, the first thickness greater than the second thickness.