Battery pack temperature optimization control system

• US 20100212338A1
• Filed: 03/18/2009
• Published: 08/26/2010
• Est. Priority Date: 02/20/2009
• Status: Active Grant

• Current Assignee: Tesla Inc.
• Original Assignee: Tesla Motors Incorporated (Tesla Inc.)
• Inventors: Kohn, Scott Ira, Mehta, Vineet Haresh, Straubel, Jeffrey Brian, Hermann, Weston Arthur, Kelty, Kurt Russell
• Granted Patent: US 8,082,743 B2
• Time in Patent Office: Days
• US Class Current: 62/118
• CPC Class Codes: B60H 1/00278 for the battery arrangement of batteries B60R16/04
• CPC Class Codes: B60H 2001/00307 Component temperature regulation using a liquid flow
• CPC Class Codes: H01M 10/486 for measuring temperature
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/615 Heating or keeping warm
• CPC Class Codes: H01M 10/625 Vehicles
• CPC Class Codes: H01M 10/633 characterised by algorithms, flow charts, software details or the like
• CPC Class Codes: H01M 10/635 based on ambient temperature
• CPC Class Codes: H01M 10/6568 characterised by flow circuits, e.g. loops, located externally to the cells or cell casings
• CPC Class Codes: H01M 10/663 the system being an air-conditioner or an engine
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A method and apparatus for limiting the adverse effects of temperature on the electrical energy storage system (ESS) of an electric vehicle after the vehicle has been turned off are provided. In general, whether or not coolant is circulated through a coolant loop coupled to the ESS depends on the difference between the ambient temperature and a preset temperature, the preset temperature typically corresponding to the temperature of the ESS.

Claims

1. A thermal management system for an electric vehicle comprising:

an electrical energy storage system (ESS) coupled to an electric vehicle powertrain, said electrical ESS supplying power to an electric motor of said electric vehicle powertrain;

a cooling system comprised of a coolant within a coolant loop, said coolant loop in thermal communication with said electrical ESS, said coolant system further comprised of a coolant pump for pumping said coolant through said coolant loop, said coolant system further comprised of a radiator coupled to said coolant loop, wherein said coolant passes through said radiator as said coolant is pumped through said coolant loop with said coolant pump;

a temperature control system coupled to said cooling system, wherein said cooling system is under the control of said temperature control system, wherein said temperature control system further comprises;

a vehicle condition monitor, wherein said vehicle condition monitor outputs a first condition signal when said electric vehicle is on and outputs a second condition signal when said electric vehicle is off;

an ambient temperature monitor for determining ambient temperature;

a comparator circuit for comparing said ambient temperature with a preset temperature, wherein said comparator circuit outputs a first signal when said ambient temperature is less than said preset temperature and outputs a second signal when said ambient temperature is greater than said preset temperature; and

a cooling system controller coupled to said cooling system, said cooling system controller configured to output a control signal to said cooling system when said vehicle condition monitor outputs said second condition signal, said cooling system controller further configured to receive said first and second signals from said comparator circuit, wherein said control signal activates said coolant pump when said cooling system controller receives said first signal from said comparator circuit, and wherein said control signal deactivates said coolant pump when said cooling system controller receives said second signal from said comparator circuit.

2. The thermal management system of claim 1, further comprising at least one temperature sensor in thermal communication with said electrical ESS, said at least one temperature sensor monitoring an ESS temperature, wherein said preset temperature is set to said ESS temperature.

3. The thermal management system of claim 1, further comprising:

at least one temperature sensor in thermal communication with said electrical ESS, said at least one temperature sensor monitoring an ESS temperature; and

a second comparator circuit for comparing said ESS temperature with a preset ESS target temperature, wherein said second comparator circuit outputs a cooling system deactivation signal to said cooling system controller when said ESS temperature is less than said preset ESS target temperature, and wherein said control signal from said cooling system controller deactivates said coolant pump when said cooling system controller receives said cooling system deactivation signal from said second comparator circuit.

4. The thermal management system of claim 3, wherein said preset temperature is set to said ESS temperature.

5. The thermal management system of claim 1, further comprising:

a refrigeration system independent of said cooling system;

a heat exchanger in thermal communication with said refrigeration system and in thermal communication with said cooling system via said coolant loop;

at least one temperature sensor in thermal communication with said electrical ESS, said at least one temperature sensor monitoring an ESS temperature; and

a second comparator circuit for comparing said ESS temperature with a preset ESS target temperature range, wherein said second comparator circuit outputs a first cooling system command signal to said cooling system controller when said ESS temperature is lower than said preset ESS target temperature range, wherein said second comparator circuit outputs a second cooling system command signal to said cooling system controller when said ESS temperature is within said preset ESS target temperature range, and wherein said second comparator circuit outputs a third cooling system command signal to said cooling system controller when said ESS temperature is greater than said preset ESS target temperature range; and

wherein said control signal from said cooling system controller deactivates said coolant pump and said refrigeration system when said cooling system controller receives said first cooling system command signal from said second comparator circuit, and wherein said control signal from said cooling system controller activates said coolant pump and said refrigeration system when said cooling system controller receives said third cooling system command signal from said second comparator circuit.

6. The thermal management system of claim 5, wherein said preset temperature is set to said ESS temperature.

7. The thermal management system of claim 1, further comprising:

at least one temperature sensor in thermal communication with said electrical ESS, said at least one temperature sensor monitoring an ESS temperature; and

a second comparator circuit for comparing said ESS temperature with a preset ESS target temperature range, wherein said second comparator circuit outputs a third signal when said ESS temperature is lower than said preset ESS target temperature range, and wherein said second comparator circuit outputs a fourth signal when said ESS temperature is within said preset ESS target temperature range;

a heater coupled to said coolant loop, wherein said cooling system controller is coupled to said heater, wherein said cooling system controller is further configured to receive said third and fourth signals from said second comparator circuit; and

wherein said control signal from said cooling system controller activates said coolant pump and activates said heater when said cooling system controller receives said third signal from said second comparator circuit, and wherein said control signal from said cooling system controller deactivates said coolant pump when said cooling system controller receives said fourth signal from said second comparator circuit.

8. The thermal management system of claim 1, further comprising:

a refrigeration system independent of said cooling system;

a heat exchanger in thermal communication with said refrigeration system and in thermal communication with said cooling system via said coolant loop;

at least one temperature sensor in thermal communication with said electrical ESS, said at least one temperature sensor monitoring an ESS temperature; and

a second comparator circuit for comparing said ESS temperature with a first preset ESS target temperature range, wherein said second comparator circuit outputs a third signal when said ESS temperature is higher than said first preset ESS target temperature range, wherein said ESS temperature is compared with a second preset ESS target temperature range by a third comparator circuit when said ESS temperature is lower than said first preset ESS target temperature range, wherein said third comparator circuit outputs a fourth signal when said ESS temperature is lower than said second preset ESS target temperature range, and wherein said third comparator circuit outputs a fifth signal when said ESS temperature is lower than said second preset ESS target temperature range;

a heater coupled to said coolant loop, wherein said cooling system controller is coupled to said heater, wherein said cooling system controller is further configured to receive said third signal from said second comparator circuit and configured to receive said fourth and fifth signals from said third comparator circuit; and

wherein said control signal from said cooling system controller activates said coolant pump and said refrigeration system when said cooling system controller receives said third signal from said second comparator circuit, wherein said control signal from said cooling system controller activates said coolant pump and activates said heater when said cooling system controller receives said fourth signal from said third comparator circuit, and wherein said control signal from said cooling system controller deactivates said coolant pump when said cooling system controller receives said fifth signal from said third comparator circuit.

9. The thermal management system of claim 1, further comprising a state of charge (SOC) sensor coupled to said electrical ESS and to said temperature control system, said SOC sensor monitoring a current SOC of said electrical ESS, wherein said cooling system controller is configured to output a deactivation signal to said cooling system when said current SOC is less than a preset target SOC.

10. The thermal management system of claim 1, wherein said ambient temperature monitor is comprised of an ambient temperature sensor.

11. The thermal management system of claim 1, wherein said ambient temperature monitor is further comprised of:

a clock for providing local time;

a global positioning system for determining vehicle location; and

means for accessing a data base, said data base providing temperature data as a function of local time and said vehicle location.

12. A thermal management system for an electric vehicle comprising:

an electrical energy storage system (ESS) coupled to an electric vehicle powertrain, said electrical ESS supplying power to an electric motor of said electric vehicle powertrain;

a cooling system comprising;

a coolant within a coolant loop, wherein a first portion of said coolant loop is in thermal communication with a first section of said electrical ESS and a second portion of said coolant loop is in thermal communication with a second section of said electrical ESS;

a coolant pump for pumping said coolant through said coolant loop;

a first valve for controlling flow through said first portion of said coolant loop;

a second valve for controlling flow through said second portion of said coolant loop; and

a radiator coupled to said coolant loop, wherein said coolant passes through said radiator as said coolant is pumped through said coolant loop with said coolant pump;

at least one temperature sensor in thermal communication with said first section of said electrical ESS and monitoring a first section ESS temperature;

at least one temperature sensor in thermal communication with said second section of said electrical ESS and monitoring a second section ESS temperature;

a temperature control system coupled to said cooling system, wherein said cooling system is under the control of said temperature control system, wherein said temperature control system further comprises;

a vehicle condition monitor, wherein said vehicle condition monitor outputs a first condition signal when said electric vehicle is on and outputs a second condition signal when said electric vehicle is off;

an ambient temperature monitor for determining ambient temperature;

a first comparator circuit for comparing said ambient temperature with said first section ESS temperature, wherein said first comparator circuit outputs a first signal when said ambient temperature is less than said first section ESS temperature and outputs a second signal when said ambient temperature is greater than said first section ESS temperature;

a second comparator circuit for comparing said ambient temperature with said second section ESS temperature, wherein said second comparator circuit outputs a third signal when said ambient temperature is less than said second section ESS temperature and outputs a fourth signal when said ambient temperature is greater than said second section ESS temperature; and

a cooling system controller coupled to said cooling system, said cooling system controller configured to output a control signal to said cooling system when said vehicle condition monitor outputs said second condition signal, said cooling system controller further configured to receive said first and second signals from said first comparator circuit and said third and fourth signals from said second comparator circuit, wherein said control signal activates said coolant pump and opens said first valve when said cooling system controller receives said first signal from said first comparator circuit, wherein said control signal activates said coolant pump and opens said second valve when said cooling system controller receives said third signal from said second comparator circuit, wherein said control signal deactivates said coolant pump when said cooling system controller receives said second signal from said first comparator circuit, and wherein said control signal deactivates said coolant pump when said cooling system controller receives said fourth signal from said second comparator circuit.

13. The thermal management system of claim 12, further comprising:

a refrigeration system independent of said cooling system;

a heat exchanger in thermal communication with said refrigeration system and in thermal communication with said cooling system via said coolant loop;

a third comparator circuit for comparing said first section ESS temperature with a preset ESS target temperature range, wherein said third comparator circuit outputs a first cooling system command signal to said cooling system controller when said first section ESS temperature is lower than said preset ESS target temperature range, wherein said third comparator circuit outputs a second cooling system command signal to said cooling system controller when said first section ESS temperature is within said preset ESS target temperature range, and wherein said third comparator circuit outputs a third cooling system command signal to said cooling system controller when said first section ESS temperature is greater than said preset ESS target temperature range; and

wherein said control signal from said cooling system controller deactivates said coolant pump and said refrigeration system when said cooling system controller receives said first cooling system command signal from said third comparator circuit, and wherein said control signal from said cooling system controller activates said coolant pump and said refrigeration system and opens said first valve when said cooling system controller receives said third cooling system command signal from said third comparator circuit.

14. A method of controlling the temperature of an electrical energy storage system (ESS) coupled to an electric powertrain of an electric vehicle, the method comprising the steps of:

a) monitoring an operational condition of said electric vehicle, wherein said operational condition is either in a first state of operation or a second state of operation, wherein said first state of operation corresponds to said electric vehicle being turned on, and wherein said second state of operation corresponds to said electric vehicle being turned off, wherein when said electric vehicle is in said second state of operation the method further comprises the steps of;

b) determining a current ambient temperature;

c) comparing said current ambient temperature with a preset temperature;

d) circulating coolant through a coolant loop in thermal communication with said electrical ESS and through a radiator coupled to said coolant loop if said current ambient temperature is lower than said preset temperature;

e) suspending circulation of said coolant through said coolant loop if said current ambient temperature is greater than said preset temperature; and

f) repeating steps b) through e).

15. The method of claim 14, further comprising the steps of determining a current ESS temperature with at least one temperature sensor, and setting said preset temperature to said current ESS temperature.

16. The method of claim 14, further comprising the steps of:

g) determining a current ESS temperature with at least one temperature sensor;

h) comparing said current ESS temperature with an ESS target temperature; and

i) suspending circulation of said coolant through said coolant loop if said current ESS temperature is lower than said ESS target temperature, wherein steps g) through i) are performed prior to step c).

17. The method of claim 14, further comprising the steps of:

g) determining a current ESS temperature with at least one temperature sensor;

h) comparing said current ESS temperature with an ESS target temperature range;

i) suspending circulation of said coolant through said coolant loop if said current ESS temperature is lower than said ESS target temperature range;

j) circulating coolant through said coolant loop if said current ESS temperature is greater than said ESS target temperature range, wherein said coolant loop is coupled to a heat exchanger;

k) operating a refrigeration system in thermal communication with said heat exchanger if said current ESS temperature is greater than said ESS target temperature range; and

l) performing steps c) through f) if said current ESS temperature is within said ESS target temperature range.

18. The method of claim 17, further comprising the step of setting said preset temperature to said current ESS temperature.

19. The method of claim 14, further comprising the steps of:

g) determining a current ESS temperature with at least one temperature sensor;

h) comparing said current ESS temperature with an ESS target temperature range;

i) circulating coolant through said coolant loop if said current ESS temperature is lower than said ESS target temperature range;

j) operating a heater in thermal communication with said coolant loop if said current ESS temperature is lower than said ESS target temperature range;

k) suspending circulation of said coolant through said coolant loop if said current ESS temperature is within said ESS target temperature; and

l) performing steps c) through e) if said current ESS temperature is greater than said ESS target temperature, wherein steps g) through l) are performed prior to step c).

20. The method of claim 14, further comprising the steps of:

g) determining a current ESS temperature with at least one temperature sensor;

h) comparing said current ESS temperature with a first ESS target temperature range;

i) circulating coolant through said coolant loop if said current ESS temperature is greater than said first ESS target temperature range, wherein said coolant loop is coupled to a heat exchanger;

j) operating a refrigeration system in thermal communication with said heat exchanger if said current ESS temperature is greater than said first ESS target temperature range;

k) comparing said current ESS temperature with a second ESS target temperature range if said current ESS temperature is lower than said first ESS target temperature range;

l) circulating coolant through said coolant loop if said current ESS temperature is lower than said second ESS target temperature range;

m) operating a heater in thermal communication with said coolant loop if said current ESS temperature is lower than said second ESS target temperature range;

n) suspending circulation of said coolant through said coolant loop if said current ESS temperature is within said second ESS target temperature; and

o) performing steps c) through e) if said current ESS temperature is within than said first ESS target temperature, wherein steps g) through n) are performed prior to step c).

21. The method of claim 14, further comprising the steps of:

g) determining a current state of charge (SOC) of said electrical ESS;

h) comparing said current SOC with a preset target SOC; and

i) terminating ESS cooling and bypassing steps c) through f) if said current SOC is lower than said preset target SOC.

22. The method of claim 14, wherein said current ambient temperature determining step further comprises the step of monitoring at least one ambient temperature monitor.

23. The method of claim 14, wherein said current ambient temperature determining step further comprises the steps of:

determining a local time;

determining a vehicle location; and

accessing a data base, said data base providing current ambient temperature data as a function of said local time and said vehicle location.

24. A method of controlling the temperature of an electrical energy storage system (ESS) coupled to an electric powertrain of an electric vehicle, the method comprising the steps of:

a) monitoring an operational condition of said electric vehicle, wherein said operational condition is either in a first state of operation or a second state of operation, wherein said first state of operation corresponds to said electric vehicle being turned on, and wherein said second state of operation corresponds to said electric vehicle being turned off, wherein when said electric vehicle is in said second state of operation the method further comprises the steps of;

b) determining a current ambient temperature;

c) determining a first section ESS temperature corresponding to a first section of said electrical ESS;

d) comparing said current ambient temperature with said first section ESS temperature;

e) circulating coolant through a first portion of a coolant loop in thermal communication with said first section of said electrical ESS and through a radiator coupled to said coolant loop if said current ambient temperature is lower than said first section ESS temperature;

f) suspending circulation of said coolant through said first portion of said coolant loop if said current ambient temperature is greater than said first section ESS temperature;

g) determining a second section ESS temperature corresponding to a second section of said electrical ESS;

h) comparing said current ambient temperature with said second section ESS temperature;

i) circulating coolant through a second portion of said coolant loop in thermal communication with said second section of said electrical ESS and through said radiator coupled to said coolant loop if said current ambient temperature is lower than said second section ESS temperature;

j) suspending circulation of said coolant through said second portion of said coolant loop if said current ambient temperature is greater than said second section ESS temperature;

k) repeating steps b) through j).

25. The method of claim 24, further comprising the steps of:

l) comparing said first section ESS temperature with an ESS target temperature range;

m) suspending circulation of said coolant through said coolant loop if said first section ESS temperature is lower than said ESS target temperature range;

n) circulating coolant through said first portion and through said second portion of said coolant loop and through said radiator coupled to said coolant loop if said first section ESS temperature is greater than said ESS target temperature range, wherein said coolant loop is coupled to a heat exchanger;

o) operating a refrigeration system in thermal communication with said heat exchanger if said first section ESS temperature is greater than said ESS target temperature range; and

l) performing steps c) through k) if said first section ESS temperature is within said ESS target temperature range.