US-20260124958-A1 - SYSTEM AND METHOD FOR BATTERY COOLING

Abstract

Systems and methods cooling battery cells of a battery are described. The system may include a plurality of spool valves to create a plurality of coolant flow paths through a battery pack so that a temperature differential between battery cells may be reduced. A controller adjusts positions of the spool valves according to battery cell temperature.

Inventors

• Xiaogang Zhang

Assignees

• FORD GLOBAL TECHNOLOGIES, LLC

Dates

Publication Date

20260507

Application Date

20241106

Claims (20)

1. 1 . A method for controlling battery pack temperature, comprising: via one or more controllers, adjusting a first valve position to direct coolant flow to one of a plurality of battery pack coolant inlets in response to a battery cell temperature.
2. 2 . The method of claim 1 , further comprising adjusting a second valve position to direct coolant flow from one of a plurality of battery pack coolant outlets in response to the battery cell temperature.
3. 3 . The method of claim 2 , where the plurality of battery pack coolant inlets include a first coolant inlet, a second coolant inlet, and a third coolant inlet.
4. 4 . The method of claim 3 , where the plurality of battery pack coolant outlets include a first coolant outlet, a second coolant outlet, and a third coolant outlet.
5. 5 . The method of claim 1 , where the first valve position is a position of a spool valve.
6. 6 . The method of claim 1 , where the battery cell temperature is a difference in temperature between a first battery cell and a second battery cell.
7. 7 . The method of claim 1 , further comprising adjusting a speed of a coolant pump in response to the battery cell temperature.
8. 8 . A battery pack temperature control system, comprising: an inlet spool control valve; an outlet spool control valve; a plurality of coolant inlets; a plurality of coolant outlets; a plurality of battery cells; and one or more controllers including executable instructions stored in controller memory that cause the one or more controllers to adjust the inlet spool control valve and the outlet spool control valve in response to a temperature of one or more of the plurality of battery cells.
9. 9 . The battery pack temperature control system of claim 8 , where the inlet spool control valve may be adjusted to three different positions to provide three different flow paths through the inlet spool control valve.
10. 10 . The battery pack temperature control system of claim 9 , where the outlet spool control valve may be adjusted to three different positions to provide three different flow paths through the outlet spool control valve.
11. 11 . The battery pack temperature control system of claim 8 , where the inlet spool control valve is in fluidic communication with the plurality of coolant inlets.
12. 12 . The battery pack temperature control system of claim 8 , where the outlet spool control valve is in fluidic communication with the plurality of coolant outlets.
13. 13 . The battery pack temperature control system of claim 8 , where the plurality of battery cells are contained in a housing.
14. 14 . The battery pack temperature control system of claim 8 , further comprising additional executable instructions to operate the battery pack temperature control system in five different cooling configurations.
15. 15 . The battery pack temperature control system of claim 14 , where the five different cooling configurations are based on different positions of the inlet spool control valve and different positions of the outlet spool control valve.
16. 16 . A battery pack temperature control system, comprising: an inlet spool control valve; an outlet spool control valve; a plurality of coolant inlets; a plurality of coolant outlets; a coolant pump; a coolant reservoir; a plurality of battery cells enclosed in a housing; and one or more controllers including executable instructions stored in controller memory that cause the one or more controllers to adjust the inlet spool control valve and the outlet spool control valve to produce a plurality of different coolant flow paths through the housing.
17. 17 . The battery pack temperature control system of claim 16 , further comprising additional instructions to adjust a speed of the coolant pump in response to a temperature of one of the plurality of battery cells.
18. 18 . The battery pack temperature control system of claim 16 , where the plurality of coolant inlets are arranged along a first side of the housing.
19. 19 . The battery pack temperature control system of claim 18 , where the plurality of coolant outlets are arranged along a second side of the housing.
20. 20 . The battery pack temperature control system of claim 16 , further comprising a chiller, the chiller in fluidic communication with the coolant pump and the coolant reservoir.

Description

FIELD The present description relates to methods and a system for cooling a battery pack that is comprised of a plurality of battery cells. In one example, the battery pack may be installed in an electric vehicle. BACKGROUND AND SUMMARY An electric vehicle may include a traction battery for propelling a vehicle. The traction battery may be comprised of a plurality of battery cells. The plurality of battery cells may include battery cells that are arranged in parallel and in series. The temperature of these battery cells may increase during charging and/or discharging of the battery cells. In order to provide long battery life and charge capacity it may be desirable to keep each battery cell at a temperature that is equal to temperatures of the other battery cells. In other words, it may be desirable to operate battery cells of a battery with as little temperature difference across the plurality of battery cells as may be possible. In an example, a method for controlling battery pack temperature, comprises, via one or more controllers, adjusting a first valve position to direct coolant flow to one of a plurality of battery pack coolant inlets in response to a battery cell temperature. BRIEF DESCRIPTION OF THE DRAWINGS The advantages described herein will be more fully understood by reading an example of an embodiment, referred to herein as the Detailed Description, when taken alone or with reference to the drawings, where: FIG. 1 is a schematic view of an example electric vehicle; FIG. 2 is a schematic perspective view of an example battery pack is shown; FIG. 3 shows plots of example battery cell temperatures in the battery pack of FIG. 2; FIG. 4 shows a schematic view of an example battery cooling system; FIGS. 5A-5C show a cut-away view of an inlet spool valve in three different operating states; FIGS. 5D-5F show a cut-away view of an outlet spool valve in three different operating states; FIGS. 6A-6E show different operating modes for the battery cooling system of FIG. 4; FIG. 7 shows a flowchart of a method for operating the battery cooling system of FIG. 4; and FIG. 8 shows a flowchart of a second method for operating the battery cooling system of FIG. 4. DETAILED DESCRIPTION The present description is related to a cooling system for a battery pack that is comprised of a plurality of battery cells. The cooling system may include two spool valves that control flow of coolant into and out of the battery pack. The cooling system also includes a controller and a control routine to lower differential temperature within the battery pack. The battery pack may be included in an electric vehicle as shown in FIG. 1. FIG. 2 shows an example coolant flow path through an example battery pack and FIG. 3 shows battery cell temperature profiles for battery cells shown in FIG. 2. A battery pack coolant system according to the present description is shown in FIG. 4. Various positions of coolant flow control valves are shown in FIGS. 5A-5F. Several coolant flow control modes for the coolant system of FIG. 4 are shown in FIGS. 6A-6E. A method for operating the battery pack cooling system of FIG. 4 is shown in FIG. 7. A second method for operating the battery pack cooling system of FIG. 4 is shown in FIG. 8. Battery cells within a battery may be cooled or heated to be maintained at a desirable temperature. Operating the battery cells at or near the desired temperature may extend battery life and permit desirable rates of charging and discharging of the battery cells. To maintain the battery cells at or near the desired temperature, a battery pack temperature control system may be applied. The battery pack temperature control system, which may be referred to as a battery pack cooling system, may apply a heat exchanger to extract heat from the battery pack by flowing coolant past battery cells. This arrangement works well to maintain battery cells near a desired temperature and battery pack temperature control system enhancements may provide additional advantages for controlling battery cells to a desired temperature. The inventor herein has recognized the above-mentioned issue and has developed a method for controlling battery pack temperature, comprising: via one or more controllers, adjusting a first valve position to direct coolant flow to one of a plurality of battery pack coolant inlets in response to a battery cell temperature. By adjusting a first valve position to direct coolant flow to one of a plurality of battery pack coolant inlets in response to a battery cell temperature, it may be possible to reduce a temperature difference between battery cells of a battery pack. For example, it may be possible to control a temperature of a battery cell that is near a coolant outlet of a battery pack so that it is closer to a temperature of a battery cell that is near a coolant inlet of the battery pack. Consequently, charge capacities and life expectancies of battery cells within a battery pack may be maintained to be more