APPARATUS, SYSTEM AND METHOD FOR CHARGE BALANCING OF INDIVIDUAL JARS IN A STRING USING JAR VOLTAGE AND TEMPERATURE, AND DETECTING AND PREVENTING THERMAL RUNAWAY

• US 20140354237A1
• Filed: 05/30/2014
• Published: 12/04/2014
• Est. Priority Date: 05/30/2013
• Status: Active Grant

• Current Assignee: CPG Beyond, Inc.
• Original Assignee: Canara Incorporated (Capitol Power Group LLC)
• Inventors: Cotton, Stephen D., Sheppard, Douglas, Hanking, Brian, Snetsinger, Cathy, Toomey, Jason W., Carmel, Michael, Yu, Tony, Triveri, Patricio A.
• Granted Patent: US 9,537,332 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/007188 the charge cycle being controlled or terminated in response to non-electric parameters

Abstract

Implementations of the present disclosure involve a system and method for load balancing a string of jars. The temperature and voltage of each jar is measured and a target voltage for the jar is set based on the measured temperature. A current is supplied to the jar in order to maintain, increase, or decrease the jar'"'"'s voltage.

Claims

1. A method of load balancing comprising:

measuring a first voltage and a first temperature of a first jar in a string of jars;

setting a first target voltage based on a nominal jar voltage associated with the first temperature;

controlling a first current to the first jar to;

maintain the first voltage when the first voltage is at the first target voltage;

increase the first voltage when the first voltage is below the first target voltage; and

decrease the first voltage when the first voltage is above the first target voltage.

2. The method of claim 1, wherein controlling the first current to the first jar comprises controlling a current bypass circuit operably coupled to the first jar, wherein the current bypass circuit receives a second current being supplied to charge the string of jars and routes a third current to bypass the first jar with the remainder of the second current being supplied to the first jar as the first current.

3. The method of claim 1, reducing the first current when the first temperature exceeds a first temperature threshold indicative of thermal runaway, disregarding the first target voltage and thereby reducing the first temperature.

4. The method of claim 3, further comprising reducing a fourth current being provided to a second jar in the string of jars, disregarding a second target voltage, the second jar located adjacent to the first jar, thereby reducing a second temperature of the second jar temperature and the first temperature.

5. The method of claim 3, further comprising generating an alert when the first temperature meets a second temperature threshold indicative of thermal runaway.

6. The method of claim 1, further comprising determining whether the first jar is malfunctioning by:

storing the first temperature and first voltage in a memory; and

generating an alert indicating that the first jar is near failure when at least one of;

the first jar has a temperature exceeding the first temperature threshold;

the first current exceeds a current threshold; and

the first jar voltage is less than a third voltage indicative of the first jar malfunctioning.

7. The method of claim 1, further comprising sending the first temperature and the first voltage to a remote computing device.

8. The method of claim 2, further comprising calculating the first current by subtracting the second current from the third current being supplied to the string of jars and sending a value of the first current to a remote computing device.

9. A load balancing system comprising:

a first battery monitor operably coupled to a first jar in a string of jars, the second battery monitor having a first voltage sensor configured to measure a first voltage of the first jar, a first temperature sensor configured to measure a first temperature of the first jar, and a first bypass circuit configured to route current to bypass the first jar;

a controller configured to receive the first jar voltage and the first jar temperature from the first battery monitor, wherein the controller;

sets a first target voltage based on a first nominal jar voltage associated with the first temperature; and

controls a first current supplied to the first jar using the first bypass circuit to;

maintain the first voltage when the first voltage is at the first target voltage;

increase the first voltage when the first voltage is below the first target voltage; and

decrease the first voltage when the first voltage is above the first target voltage.

10. The battery charging system of claim 9, further comprising a second battery monitor operably coupled to a second jar in the string of jars, the second battery monitor having a second voltage sensor configured to measure a second voltage of the second jar, a second temperature sensor configured to measure a second temperature of the second jar, and a second bypass circuit configured to route current to bypass the second jar, wherein the controller:

receives the second voltage and the second temperature;

sets a second target voltage based on a second nominal jar voltage associated with the second temperature; and

controls a second current supplied to the second jar using the second bypass circuit to;

maintain the second voltage when the second voltage is at the second target voltage;

increase the second voltage when the second voltage is below the second target voltage; and

decrease the second voltage when the second voltage is above the second target voltage.

11. The system of claim 10, wherein the controller is further configured to determine a third current for supplying to the string to charge the first jar and the second jar, wherein the third current is greater than or equal to the larger of the first current or the second current.

12. The system of claim 11, wherein a fourth current is routed through the first bypass circuit with the remainder of the third current being supplied to the first jar as the first current;

and

a fifth current is routed through the second bypass circuit with the remainder of the third current being supplied to the second jar as the second current.

13. The system of claim 12, wherein the controller is configured to provide a pulse width modulated signal to the first bypass circuit to control the fourth current though the first bypass circuit.

14. The system of claim 9, wherein the controller comprises a memory configured to store charge balancing metrics including each measured temperature and voltage and the controller is further configured to generate an alert when at least one of:

the first jar has a temperature exceeding a first temperature threshold;

the first current exceeds a current threshold; and

the first jar voltage is less than a third voltage indicative of the first jar malfunctioning.

15. The system of claim 9, wherein the controller further comprises a network interface configured to send the first temperature and the first voltage to a remote computing device.

16. The system of claim 10, wherein the controller is further configured to reduce the first current when the first temperature exceeds a first temperature threshold, disregarding the first target voltage and thereby reducing the first temperature.

17. The method of claim 16, wherein the controller is further configured to reduce a second current to a second jar to reduce the first temperature when the first temperature exceeds a second temperature threshold, disregarding a second target voltage for the second jar, the second jar located adjacent to the first jar and the first temperature is thereby reduced by reducing the second temperature.

18. A method of load balancing comprising:

measuring a first voltage and a first temperature of a first jar in a string of jars;

setting a first target voltage based on a first nominal jar voltage associated with the first temperature;

obtaining a first current based on a difference between the first voltage and the first target voltage;

measuring a second voltage and a second temperature of a second jar in the string of jars;

setting a second target voltage based on a second nominal jar voltage associated with the second temperature;

obtaining a second current based on a difference between the second voltage and the second target voltage;

obtaining a third current that is greater than or equal to a larger of the first current and the second current;

controlling the first current to maintain the first voltage when the first voltage is at the first target voltage, increase the first voltage when the first voltage is below the first target voltage, and decrease the first voltage when the first voltage is above the first target voltage by routing a first portion of the third current from the first jar using a first bypass circuit operably coupled to the first jar; and

controlling the second current to maintain the second voltage when the second voltage is at the second target voltage, increase the second voltage when the second voltage is below the second target voltage, and decrease the second voltage when the second voltage is above the second target voltage by routing a second portion of the third current from the second jar using a second bypass circuit operably coupled to the second jar.

19. The method of claim 18, further comprising reducing the first current when the first temperature exceeds a first temperature threshold thereby reducing the first temperature.

20. The method of claim 19, further comprising reducing the second current when the first temperature exceeds a second temperature threshold thereby reducing the second temperature, wherein the first jar is adjacent to the second jar and the first temperature is reduced by reducing the second temperature.