Motor vehicle cooling system and control for cooling a traction battery

1. A method for controlling an electrified vehicle having a traction battery configured to propel the vehicle and a cooling system configured to cool the traction battery, the method comprising:

receiving, by a vehicle controller, trip data representative of a planned route for the electrified vehicle;

generating, by the vehicle controller, a forecast temperature profile of the traction battery having estimated battery temperature as a function of the planned route based on the trip data and battery operating parameters; and

in response to the estimated battery temperature exceeding an associated temperature threshold for at least one point on the planned route, determining a cooling point along the planned route prior to the at least one point, and controlling the cooling system to increase cooling of the battery beginning at the cooling point to maintain actual battery temperature below the estimated battery temperature for the at least one point on the planned route.

2. The method of claim 1 wherein the cooling point determined by the controller is based on at least a traction battery heat capacity.

3. The method of claim 2 wherein the cooling point determined by the controller is determined using a weight of the electrified vehicle.

4. The method of claim 3 further comprising determining, by the controller, the weight of the electrified vehicle during operation of the electrified vehicle along a portion of the planned route.

5. The method of claim 1 wherein determining the cooling point comprises determining a required battery temperature at the cooling point to prevent the actual battery temperature from exceeding the associated temperature threshold based on the estimated battery temperature, a heat transfer coefficient between the battery and the cooling system, a heat-transferring surface area between the battery and the cooling system, a time period for controlling increased cooling, a specific heat capacity of the battery, and mass of the battery.

6. The method of claim 1 wherein determining the cooling point comprises determining a required battery temperature at the cooling point to prevent the actual battery temperature from exceeding the associated temperature threshold according to:

T

erf

=

T

Limit

-

T

m

⁢

α

⁢

x

-

T

Limit

1

-

α

*

A

*

i

c

p

*

m

where T Limit represents the associated temperature threshold, T max represents the estimated battery temperature, α represents a heat transfer coefficient between the battery and the cooling system, A represents a heat-transferring surface area between the battery and the cooling system, i represents a time period for controlling increased cooling, c p represents specific heat capacity of the battery, and m represents mass of the battery.

7. The method of claim 1 wherein determining the cooling point comprises, determining, by the controller, determining a cooling time according to:

SZP

=

c

p

*

m

*

(

T

SW

-

T

erf

)

Q

Batt

-

α

*

A

*

(

T

SW

+

T

erf

2

-

T

Cool

)

where T SW represents a second battery temperature threshold that activates the cooling system, T erf represents battery temperature at the cooling point, α represents a heat transfer coefficient between the battery and the cooling system, A represents a heat-transferring surface area between the battery and the cooling system, c p represents specific heat capacity of the battery, m represents mass of the battery Q batt represents average flow of heat that the battery generates in a time period before the cooling point, and T cool represents average coolant temperature when the cooling system is active.

8. The method of claim 1 wherein the electrified vehicle comprises a hybrid vehicle having an internal combustion engine.

9. A method for operating a motor vehicle having a traction battery and a cooling system for cooling the traction battery, the method comprising:

receiving, by a vehicle controller, trip data associated with a planned route having a battery load demand exceeding a load threshold and operating parameters of the traction battery;

evaluating the trip data and the operating parameters to determine a set of data representative of a forecast temperature profile of the traction battery;

evaluating the set of data for the forecast temperature profile of the traction battery temperature to determine a phase of cooling demand output exceeding an associated threshold while completing the planned route; and

buffer-storing thermal energy by controlling the cooling system while traveling the planned route by utilizing heat storage capacity of the traction battery before the phase of cooling output demand exceeding the threshold for providing required battery power when the battery load demand exceeds the load threshold.

10. The method of claim 9 further comprising determining a required battery temperature to which the traction battery is cooled before reaching a point on the planned route wherein the battery load demand exceeds the load threshold.

11. The method of claim 9 further comprising determining weight of the motor vehicle while traveling a section of the planned route.

12. The method of claim 11 wherein the weight of the motor vehicle is determined by comparing measured vehicle operating parameters along the section of the planned route to previously stored vehicle operating parameters.

13. A vehicle comprising:

a traction battery configured to propel the vehicle;

a cooling system configured to cool the traction battery; and

a controller configured to:

receive trip data representative of a planned route for the vehicle;

generate a forecast temperature profile of the traction battery having estimated battery temperature as a function of the planned route based on the trip data and battery operating parameters; and

in response to the estimated battery temperature exceeding an associated temperature threshold for at least one point on the planned route, determine a cooling point along the planned route prior to the at least one point, and control the cooling system to increase cooling of the battery beginning at the cooling point to maintain actual battery temperature below the estimated battery temperature for the at least one point on the planned route, wherein the controller is configured to determine the cooling point using at least a weight of the vehicle.

14. The vehicle of claim 13 wherein the controller is further configured to determine the cooling point based on at least a traction battery heat capacity.

15. The vehicle of claim 13 wherein the controller is further configured to determine the weight of the vehicle during operation of the vehicle along a portion of the planned route.

16. The vehicle of claim 13 wherein the controller is further configured to determine the cooling point by determining a required battery temperature at the cooling point to prevent the actual battery temperature from exceeding the associated temperature threshold based on the estimated battery temperature, a heat transfer coefficient between the battery and the cooling system, a heat-transferring surface area between the battery and the cooling system, a time period for controlling increased cooling, a specific heat capacity of the battery, and mass of the battery.

17. The vehicle of claim 13 wherein the controller is configured to determine the cooling point by determining a required battery temperature at the cooling point to prevent the actual battery temperature from exceeding the associated temperature threshold according to:

T

erf

=

T

Limit

-

T

m

⁢

α

⁢

x

-

T

Limit

1

-

α

*

A

*

i

c

p

*

m

where T Limit represents the associated temperature threshold, T max represents the estimated battery temperature, α represents a heat transfer coefficient between the battery and the cooling system, A represents a heat-transferring surface area between the battery and the cooling system, i represents a time period for controlling increased cooling, c p represents specific heat capacity of the battery, and m represents mass of the battery.

18. The vehicle of claim 13 wherein the controller is configured to determine the cooling point by determining a cooling time according to:

S

⁢

Z

⁢

P

=

c

p

*

m

*

(

T

SW

-

T

erf

)

Q

Batt

-

α

*

A

*

(

T

SW

+

T

erf

2

-

T

Cool

)

where T SW represents a second battery temperature threshold that activates the cooling system, T erf represents battery temperature at the cooling point, α represents a heat transfer coefficient between the battery and the cooling system, A represents a heat-transferring surface area between the battery and the cooling system, c p represents specific heat capacity of the battery, m represents mass of the battery Q batt represents average flow of heat that the battery generates in a time period before the cooling point, and T cool represents average coolant temperature when the cooling system is active.

19. The vehicle of claim 13 further comprising an internal combustion engine.