Coolant Circulation Heater for an Electric Vehicle Battery

• US 20120295141A1
• Filed: 05/17/2011
• Published: 11/22/2012
• Est. Priority Date: 05/17/2011
• Status: Active Grant

• Current Assignee: PTI EV HYBRID, Inc.
• Original Assignee: PTI EV HYBRID, Inc.
• Inventors: Allen, Robert J.
• Granted Patent: US 8,620,502 B2
• Time in Patent Office: Days
• US Class Current: 429/62
• CPC Class Codes: B60L 1/02 to electric heating circuits
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 58/27 by heating
• CPC Class Codes: H01M 10/613 Cooling or keeping cold
• CPC Class Codes: H01M 10/615 Heating or keeping warm
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An electric vehicle battery heater includes a housing having a coolant inlet and a coolant outlet. A heating element is positioned within the housing in a heat transfer relationship with coolant for transferring heat to an electric vehicle battery. A thermistor is positioned in the housing to output a signal indicative of a temperature of the battery coolant. A controller energizes the heating element when the signal represents that the coolant temperature is less than a predetermined lower limit.

Claims

1. An electric vehicle battery heater to heat a coolant flowing in a heat transfer relationship with an electric vehicle battery, the heater comprising:

a housing having a coolant inlet and a coolant outlet;

a heating element positioned within the housing in a heat transfer relationship with the coolant;

a thermistor positioned in the housing to output a signal indicative of a temperature of the battery coolant; and

a controller energizing the heating element when the signal represents that the coolant temperature is less than a predetermined lower limit.

2. The battery heater of claim 1, wherein the housing includes a body, a divider panel, and a removable cap, the heating element and the thermistor being fixed to the divider panel.

3. The battery heater of claim 2, wherein the divider panel sealingly separates first and second chambers within the housing, a heat transfer portion of the heating element being positioned within the first chamber, electrical terminals of the heating element extending through the divider panel into the second chamber, the thermistor being positioned within the second chamber and mounted in a heat transfer relationship to the divider, the heater further including a wire harness extending through the second chamber and having wires with ends electrically coupled to the terminals.

4. The battery heater of claim 1, wherein the removable cap includes a plastic material.

5. The battery heater of claim 1, wherein the coolant inlet and coolant outlet extend at substantially ninety degrees to each other.

6. The battery heater of claim 1, wherein a supply of power to the heating element is based on pulse width modulation.

7. The battery heater of claim 1, wherein the heating element includes a single uninterrupted loop.

8. The battery heater of claim 1, further including a clamp plate positioned within the second chamber and fixed to the divider panel, the thermistor being fixed to the divider panel with the clamp plate.

9. An electric vehicle battery temperature control system for varying the temperature of a coolant flowing in a heat transfer relationship with an electric vehicle battery, the temperature control system comprising:

a heater housing having a coolant inlet and a coolant outlet;

a heating element positioned within the housing in a heat transfer relationship with the coolant;

a thermistor positioned in the housing to output a signal indicative of a temperature of the battery coolant; and

a controller energizing the heating element when the signal represents that the coolant temperature is less than a predetermined lower limit, wherein the controller determines a rate of coolant temperature increase and discontinues the supply of power to the heating element based on the temperature rate of change exceeding a predetermined threshold.

10. The battery temperature control system of claim 9, further including a chiller spaced apart from the heater housing to reduce the temperature of the coolant when the temperature of the coolant exceeds a predetermined upper limit to maintain the battery coolant within a temperature range bounded by the predetermined upper and lower limits.

11. The battery temperature control system of claim 10, further including a pump providing pressurized coolant in thermal communication with the battery.

12. The battery temperature control system of claim 11, further including a flow sensor providing a signal indicative of the flow output of the pump, the controller discontinuing a supply of power to the heating element based on the flow being below a predetermined threshold.

13. The battery temperature control system of claim 9, further including a temperature sensor positioned downstream from the battery to output a signal indicative of the coolant temperature, the controller determining whether to energize the heater and chiller based on the temperature sensor signal.

14. The battery temperature control system of claim 9, wherein the housing includes a body, a divider panel, and a removable cap, the heating element and the thermistor being fixed to the divider panel.

15. The battery temperature control system of claim 14, wherein the divider panel sealingly separates first and second chambers within the housing, a heat transfer portion of the heating element being positioned within the first chamber, electrical terminals of the heating element extending through the divider panel into the second chamber, the thermistor being positioned within the second chamber and mounted in a heat transfer relationship to the divider, the heater further including a wire harness extending through the second chamber and having wires with ends electrically coupled to the terminals.

16. The battery temperature control system of claim 15, wherein the coolant inlet and coolant outlet extend at substantially ninety degrees to each other.

17. The battery temperature control system of claim 16, further including a clamp plate positioned within the second chamber and fixed to the divider panel, the thermistor being fixed to the divider panel with the clamp plate.

18. A method of controlling the temperature of a battery of an electric vehicle, the method comprising:

pumping coolant in a heat transfer relationship with the electric vehicle battery;

flowing the coolant through a heater;

positioning a thermistor within the heater to output a signal indicative of the coolant temperature;

determining a temperature of the coolant; and

energizing the heater to increase the temperature of the coolant based on the determined coolant temperature being less than a predetermined lower limit.

19. The method of claim 18, further including flowing the coolant through a chiller and energizing the chiller to reduce the coolant temperature based on the determined coolant temperature being greater than a predetermined upper limit.

20. The method of claim 18, further including determining a rate of change of coolant temperature and discontinuing a supply of power to the heater based on the rate of temperature change exceeding a predetermined threshold.