System and method for determining a battery condition
A system and method for determining whether a battery is operating in an anomalous condition can include or be configured to measure sensor data, estimate a local property of the battery using on the sensor data, and classify whether the battery is operating in the anomalous condition based on the local property.
1 . A method for determining whether a battery is experiencing a thermal disconnection comprising:
at each of a plurality of times, measuring a temperature proximal the battery;
for each temperature, estimating a local temperature of a battery cell of the battery by:
detecting a plurality of temperature jumps in the plurality of measured temperatures, wherein each temperature jump of the series of temperature jumps exceeds a threshold temperature jump amplitude; and
calculating a thermal resistance at each of the temperature jumps; and
performing a statistical test on the plurality of local temperatures to determine whether the battery is experiencing the thermal disconnection comprising performing a statistical test on the plurality of thermal resistances to determine whether the battery is experiencing the thermal disconnection.
2 . The method of claim 1 , wherein a threshold temperature jump amplitude is 0.1° C./s.
3 . The method of claim 1 , wherein the statistical test comprises at least one of a student t-test, a z-test, or an F-test.
4 . The method of claim 1 , wherein the plurality of the temperatures comprises at least 3 temperature values.
5 . The method of claim 1 , wherein estimating the local temperatures comprises using a state estimator using a thermal model of the battery to estimate the local temperature of the battery cell from the measured temperature.
6 . The method of claim 5 , further comprising: selecting the thermal model from a thermal model library; where each thermal model of the thermal model library is operable to estimate the local temperature of the battery cell; wherein each thermal model of the thermal model library is associated with the battery experiencing either a nominal condition or a thermal disconnection; wherein a statistical probability is assigned to each thermal model of the thermal model library based on the local temperature of the battery cell; wherein when the statistical probability of a thermal model associated with the battery experiencing the thermal disconnection has the greatest statistical probability, the battery is classified as experiencing the thermal disconnection.
7 . The method of claim 6 , further comprising, when the battery is classified as experiencing the thermal disconnection, determining a corrective action.
8 . A method for determining whether a battery is experiencing a thermal anomaly comprising:
at each of a plurality of times, measuring a temperature proximal the battery;
for each temperature, estimating a local temperature of a battery cell of the battery, wherein the plurality of temperatures do not include temperature readings that exceed a temperature jump larger than a threshold temperature jump, wherein the threshold temperature jump is between 0.1° C./s and 10° C./s;
performing a statistical test on the plurality of local temperatures to determine whether the battery is experiencing the thermal anomaly.
9 . The method of claim 8 , wherein the thermal anomaly comprises a thermal runaway or an anomalous battery temperature.
10 . The method of claim 8 , wherein the statistical test is performed on a plurality of local temperatures determined during steady state operation of the battery.
11 . The method of claim 8 , wherein the statistical test comprises at least one of a student t-test, a z-test, or an F-test.
12 . The method of claim 8 , wherein the plurality of the temperatures comprises at least 3 temperature values.
13 . The method of claim 8 , wherein estimating the local temperatures comprises using a state estimator using a thermal model of the battery to estimate the local temperature of the battery cell from the measured temperature.
14 . The method of claim 13 , further comprising: selecting the thermal model from a thermal model library; where each thermal model of the thermal model library is operable to estimate the local temperature of the battery cell; wherein each thermal model of the thermal model library is associated with the battery experiencing either a nominal condition or a thermal anomaly; wherein a statistical probability is assigned to each thermal model of the thermal model library based on the local temperature of the battery cell; wherein when the statistical probability of a thermal model associated with the battery experiencing the thermal anomaly has the greatest statistical probability, the battery is classified as experiencing the thermal anomaly.
15 . The method of claim 14 , further comprising, when the battery is classified as experiencing the thermal anomaly, determining a corrective action.
16 . A system for detecting anomalous thermal behavior in a battery comprising:
a thermometer configured to measure a temperature dataset associated with the battery;
a state estimator operable to determine a local battery cell temperature of the battery using the temperature dataset;
a classifier configured to classify whether the battery is experiencing anomalous thermal behavior based on the determined local battery cell temperature, wherein the classifier is operable in:
a thermal disconnection mode wherein the classifier is operable to classify the anomalous thermal behaviour as a thermal disconnection using a thermal resistance dataset derived from jump changes in the local battery cell temperature exceeding a threshold jump change, wherein the jump changes are at least about 0.1° C./s to classify the thermal disconnection; and
an anomalous temperature mode wherein the classifier is operable to classify the anomalous thermal behavior based on steady state readings of the local battery cell temperature.
17 . The system of claim 16 , wherein the local temperature of the battery cell is modelled as a function of the temperature dataset, a historic temperature dataset, an ambient temperature, and a heat flux.
18 . The system of claim 16 , wherein the classifier is configured to classify whether the battery is operating in the anomalous condition during operation of the battery.