Thermal runaway detection methods and warning systems

Patent metadata

Field	Value
Publication number	US-11784359-B2
Application number	US-202117392609-A
Country	US
Kind code	B2
Filing date	Aug 3, 2021
Priority date	Aug 3, 2021
Publication date	Oct 10, 2023
Grant date	Oct 10, 2023

Abstract

A method for detecting thermal runaway of a cell includes: positioning a battery pack having multiple cells in an automobile vehicle; measuring a cell voltage of the multiple cells at a predetermined sample rate; and identifying if the cell voltage decreases and modulates coincident with a cell surface temperature increase indicating initiation of a cell short.

First claim

What is claimed is:

1. A method for detecting thermal runaway of a cell, comprising:
positioning a battery pack having multiple cells in an automobile vehicle;
measuring, using a controller having at least one computer individually having at least one processor and at least one memory storing instructions, a cell voltage of the multiple cells at a predetermined sample rate;
identifying, using the controller, if the cell voltage decreases and modulates indicating initiation of a cell short coincident with or preceding a cell surface temperature increase indicating initiation of a thermal runaway event;
identifying if a power spectrum exceeds a predetermined threshold following initiation of the cell short;
initiating, using the controller, an alarm after the predetermined threshold is exceeded;
confirming the automobile vehicle to be stopped prior to measuring the cell voltage;
identifying if a cell threshold temperature is reached defining approximately 70 C; and
identifying if a cell temperature rise up to approximately 500 C occurs within approximately 5 seconds after the cell temperature reaches the threshold temperature during the battery cell thermal runaway event; and
initiating, using the controller, action following the initiation of the alarm including at least one of:
releasing, using the controller, a battery pack pressure;
communicating, using the controller, a warning via a smart phone to a vehicle operator; and
contacting, using the controller, an emergency service.

2. The method of claim 1 , further including determining a mean value of all cell voltages of the multiple cells by subtracting a minimum cell voltage from a sum the cell voltages.

3. The method of claim 2 , further including:
calculating a derivative of the cell voltage of individual ones of the multiple cells with respect to time; and
passing the derivative of the cell voltage through a buffer.

4. The method of claim 3 , further including calculating a fast fourier transform power spectrum applying the derivative of the cell voltage of the multiple cells with respect to time.

5. The method of claim 4 , further including calculating a released energy applying the power spectrum.

6. The method of claim 1 , further including initiating an action following the initiation of the alarm including at least one of:
stopping a charging operation of the battery pack;
initiating flow of a coolant into the battery pack; and
communicating a status of the battery pack to a remote cloud-based security service.

7. The method of claim 1 , further including continuing to analyze the cell voltage and the cell surface temperature following the initiation of the cell short and during a time period having a cell voltage decrease and rapid cell voltage modulation and as the cell surface temperature increases.

8. A method for detecting thermal runaway of a cell, comprising:
positioning a battery pack having multiple cells in an automobile vehicle;
measuring, using a controller having at least one computer individually having at least one processor and at least one memory storing instructions, a cell voltage of the multiple cells at a predetermined sample rate;
identifying, using the controller, if a cell short is occurring in at least one of the multiple cells;
decomposing a signal of the cell voltage into multiple signal time domain scales through a scalable wavelet filter applying a discrete wavelet distribution (DWT);
determining, using the controller, if a cell surface temperature increases to or above a threshold temperature indicating initiation of a cell thermal runaway event;
identifying if a power spectrum exceeds a predetermined threshold following initiation of the cell short;
initiating, using the controller, an alarm after the predetermined threshold is exceeded; and initiating, using the controller, an action following the initiation of the alarm including at least one of:
releasing, using the controller, a battery pack pressure;
communicating, using the controller, a warning via a smart phone to a vehicle operator; and
contacting, using the controller, an emergency service.

9. The method of claim 8 , further including:
passing a cell voltage signal through the wavelet filter; and
applying a scaling function to differentiate and remove frequencies of the signal predesignated as noise.

10. The method of claim 9 , further including applying the scaling function to split a first high frequency extraction portion into a first high frequency component and a first low frequency extraction portion into a first low frequency component.

11. The method of claim 10 , further including:
halving the low frequency component from the first low frequency extraction portion; and
generating level 1 coefficients.

12. The method of claim 11 , further including:
calculating a derivative of the cell voltage of individual ones of the multiple cells with respect to time;
calculating a fast fourier transform power spectrum applying the derivative of the cell voltage of the multiple cells with respect to time;
calculating a released energy applying the power spectrum; and
initiating an alarm if the power spectrum exceeds a predetermined spectrum threshold following initiation of the cell short.

13. The method of claim 8 , further including identifying if the cell voltage decreases and modulates coincident with the cell surface temperature increase.

14. The method of claim 8 , further including stopping a charging operation of the battery pack following the initiation of the alarm.

15. The method of claim 8 , further including initiating flow of a coolant into the battery pack following the initiation of the alarm.

16. The method of claim 8 , further including communicating a status of the battery pack to a remote cloud-based security service following the initiation of the alarm.

17. A system for detecting thermal runaway of a cell, comprising:
a controller having at least one computer, with the at least one computer individually having:
at least one processor; and
at least one memory storing instructions, such that the at least one processor is programmed to:
confirm an automobile vehicle stop;
measure a cell voltage of multiple cells of a battery pack of the automobile vehicle at a predetermined sample rate;
identify a cell short by a cell voltage decrease and a start of cell voltage modulation;
identify if a power spectrum exceeds a predetermined threshold following initiation of the cell short;
indicate, a battery cell thermal runaway event in response to a cell threshold temperature being reached;
initiate an alarm after the threshold temperature is reached;
calculating a derivative of the cell voltage of individual ones of the multiple cells calculated with respect to time;
calculating a fast fourier transform power spectrum calculated applying the derivative of the cell voltage of the multiple cells with respect to time;
calculating a released energy calculated by applying the power spectrum; and
initiating the alarm when the power spectrum exceeds a predetermined threshold following initiation of the cell short; and
initiate an action following the initiation of the alarm including at least one of:
release a battery pack pressure;
communicate a warning via a smart phone to a vehicle operator; and
contact an emergency service.

18. The system of claim 17 , further including:
a cell voltage signal passed through a wavelet filter;
a scaling function applied to split a first high frequency extraction portion of the cell voltag

Assignees

• Gm Global Tech Operations Llc

Inventors

• Wang Yue-Yun
• Gao Jian
• Dernotte Jeremie
• Parrish Scott E

Classifications

• H01M10/482 Primary

  for several batteries or cells simultaneously or sequentially · CPC title

• B60L58/26

  by cooling · CPC title

• H01M10/425

  Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing (printed circuits H05K1/00) · CPC title

• H01M10/486

  for measuring temperature · CPC title

• H01M2010/4278

  Systems for data transfer from batteries, e.g. transfer of battery parameters to a controller, data transferred between battery controller and main controller · CPC title