Mitigating airlock in cooling channels for large area cooling systems for batteries

1 . A cooling system comprising:

a cooling channel having a nominal width;

N longitudinal portions of the cooling channel, where N is an integer greater than one;

an inlet connected to an end of a first one of the N longitudinal portions of the cooling channel;

an outlet connected to an end of a last one of the N longitudinal portions of the cooling channel; and

at least one U-turn location within the cooling channel connecting ends of at least two middle ones of the N longitudinal portions of the cooling channel,

wherein the cooling channel at the at least one U-turn location is tapered such that the cooling channel includes a reduced channel width at the at least one U-turn location relative to the nominal width,

wherein the N longitudinal portions of the cooling channel are arranged over one another in a vertical direction,

wherein the cooling channel includes an upper cooling channel, and wherein only a bottom side of the upper cooling channel at the at least one U-turn location is tapered such that the reduced channel width of the upper cooling channel progressively narrows towards an upper side of the upper cooling channel at the at least one U-turn location,

wherein the cooling channel includes a lower cooling channel, and wherein only a bottom side of the lower cooling channel at the at least one U-turn location is tapered such that the reduced channel width of the lower cooling channel progressively narrows towards an upper side of the lower cooling channel at the at least one U-turn location.

2 . The cooling system of claim 1 , wherein the cooling channel is tapered at the at least one U-turn location in a range from 30% to 70% from the nominal width.

3 . The cooling system of claim 1 , further comprising B annular baffles arranged in the at least one U-turn location, where B is an integer greater than zero, wherein the B annular baffles divide the cooling channel into subchannels arranged in a nested configuration of parallel channels.

4 . The cooling system of claim 3 , wherein B is greater than one and the B annular baffles are uniformly spaced.

5 . The cooling system of claim 3 , wherein B is greater than two and the B annular baffles are spaced by an increasing width from an innermost to an outermost of the B annular baffles.

6 . The cooling system of claim 1 , further comprising a surface treatment film coated on an inner surface of the at least one U-turn location, wherein the surface treatment film is configured to reduce a coolant-wall contact angle of the cooling channel at the at least one U-turn location from the nominal width.

7 . The cooling system of claim 1 , wherein the at least one U-turn location comprises a shape memory alloy.

8 . A vehicle comprising:

a battery system; and

the cooling system of claim 1 in thermal contact with one or more surfaces of the battery system.

9 . A cooling system comprising:

a cooling channel having a nominal width;

N longitudinal portions of the cooling channel extending longitudinally, where N is an integer greater than one;

an inlet connected to an end of a first one of the N longitudinal portions of the cooling channel;

an outlet connected to an end of a last one of the N longitudinal portions of the cooling channel;

at least one U-turn location within the cooling channel connecting ends of at least two middle ones of the N longitudinal portions of the cooling channel; and

B annular baffles arranged in within the cooling channel at the at least one U-turn location where B is an integer greater than zero, wherein the B annular baffles divide the cooling channel at the at least one U-turn location into subchannels arranged in a nested configuration of parallel channels,

wherein the cooling channel includes an upper cooling channel and a lower cooling channel,

wherein only a bottom side of the upper cooling channel at the at least one U-turn location is tapered towards an upper side of the upper cooling channel at the at least one U-turn location to provide a reduced channel width that progressively narrows from the bottom side toward the upper side of the upper cooling channel,

wherein only a bottom side of the lower cooling channel at the at least one U-turn location is tapered towards an upper side of the lower cooling channel at the at least one U-turn location to provide a reduced channel width that progressively narrows from the bottom side toward the upper side of the lower cooling channel.

10 . The cooling system of claim 9 , wherein B is greater than one and the B annular baffles are uniformly spaced.

11 . The cooling system of claim 9 , wherein B is greater than two and the B annular baffles are spaced by an increasing width.

12 . The cooling system of claim 9 , wherein the N longitudinal portions of the cooling channel are arranged over one another in a vertical direction.

13 . The cooling system of claim 9 , wherein the cooling channel at the at least one U-turn location includes a reduced channel width that is tapered in a range from 30% to 70% from the nominal width.

14 . The cooling system of claim 13 , wherein the at least one U-turn location comprises a shape memory alloy.

15 . The cooling system of claim 9 , further comprising a surface treatment film coated on an inner surface of the at least one U-turn location, wherein the surface treatment film is configured to reduce a coolant-wall contact angle of the cooling channel at the at least one U-turn location from the nominal width.

16 . A cooling system comprising:

a cooling channel having a nominal width;

N longitudinal portions of the cooling channel, where N is an integer greater than one;

an inlet connected to an end of a first one of the N longitudinal portions of the cooling channel;

an outlet connected to an end of a last one of the N longitudinal portions of the cooling channel; and

at least one U-turn location connecting ends of at least two middle ones of the N longitudinal portions of the cooling channel,

wherein only a bottom side of an upper cooling channel of the cooling channel at the at least one U-turn location is tapered towards an upper side of the upper cooling channel at the at least one U-turn location,

wherein only a bottom side of a lower cooling channel of the cooling channel at the at least one U-turn location is tapered towards an upper side of the lower cooling channel at the at least one U-turn location, and

wherein a cross-sectional area of the cooling channel at the at least one U-turn location progressively decreases from the bottom side to the upper side of the upper cooling channel and from the bottom side to the upper side of the lower cooling channel such that the cooling channel is tapered at the at least one U-turn location in a range from 30% to 70% from the nominal width.