System and method for degradation based battery control
A method can include receiving battery sensor measurements, determining a state of the battery (e.g., SoH, SoC, SoE, SoP, etc. or information correlated therewith such as internal resistance, open circuit voltage, etc.), estimating an aging profile or degradation of the battery for one or more operating conditions, and determining operating conditions for the battery based on the estimated degradation.
1 . A method comprising:
for each battery of a plurality of batteries:
measuring sensor measurements comprising at least one of voltage, current, or temperature of the respective battery using a set of sensors; and
determining a state of health of the respective battery using a state estimator to process the sensor measurements;
aggregating the state of health for each battery of the plurality of batteries, wherein aggregating the state of health comprises:
aggregating the state of health for batteries from the plurality of batteries with at most a threshold utilization time to form a first aggregated dataset; and
independently aggregating the state of health for batteries from the plurality of batteries with greater than the threshold utilization time to form a second aggregated dataset; and
based on the aggregated states of health, determining operating instructions for each battery of the plurality of batteries; wherein the second aggregated dataset is used to determine operating instructions for batteries associated with the first aggregated dataset.
2 . The method of claim 1 , wherein the operating instructions minimize a total degradation of the plurality of batteries.
3 . The method of claim 1 , wherein the operating instructions comprise one or more battery operation condition selected from:
charging rate;
discharging rate;
charging voltage;
depth of discharge range;
operating temperature;
operating voltage;
storage temperature;
storage voltage;
battery operating lifetime;
accumulated charge at a given voltage load; and
total charge throughput.
4 . The method of claim 3 , wherein when the operation instructions for a battery of the plurality of batteries comprises a change in one battery operation condition, subsequent operation instructions for the battery do not comprise a change in the one battery operation condition.
5 . The method of claim 1 , wherein the operation instructions comprise instructions for operating a subset of batteries of the plurality of batteries in a diagnostic mode configured to improve observability into the state of health of the subset of batteries.
6 . The method of claim 5 , wherein the diagnostic mode comprises a pulse diagnostic mode wherein a current pulse of at least 0.1 A/s is applied to the batteries of the subset of batteries and sensor measurements are recorded contemporaneously with or subsequent to the current pulse.
7 . The method of claim 1 , wherein the state estimator comprises at least one of: a Kalman filter, an unscented Kalman filter, an extended Kalman filter, Schmidt-Kalman filter, a Gaussian process, or a particle filter.
8 . The method of claim 1 , wherein the state estimator uses one or more model selected from: battery pack geometry model, sensor model, electrical components model, thermal transport model, battery cell heat generation model, battery cell heat transport model, equivalent circuit model, or battery cell electrochemical model.
9 . The method of claim 8 , wherein the model is a parameterized model, wherein the parameterized model is parameterized as a function of one or more of: temperature, current, voltage, resistance, state of charge, battery age, time, or combinations thereof.
10 . A system comprising:
a battery comprising one or more battery cell;
a sensor configured to measure sensor measurements comprising one or more of a voltage, current, temperature, or resistance of the battery; and
a processor configured to:
receive the sensor measurements;
estimate a state of health of the battery using the sensor measurements;
aggregate the state of health of the battery with a plurality of states of health for a plurality of batteries, wherein aggregating the state of health comprises:
aggregating the states of health for the battery and batteries from the plurality of batteries with at most a threshold utilization time to form a first aggregated dataset; and
independently aggregating the states of health for the battery and batteries from the plurality of batteries with greater than the threshold utilization time to form a second aggregated dataset; and
determine a current degradation of the battery based on the state of the battery; and
determine operating conditions for the battery to achieve a target degradation based on the current degradation of the battery; wherein the second aggregated dataset is used to determine operating instructions for the battery when the battery is associated with the first aggregated dataset.
11 . The system of claim 10 , wherein the state of the battery is estimated using a state estimator comprising one of: a Kalman filter, an unscented Kalman filter, an extended Kalman filter, Schmidt-Kalman filter, a Gaussian process, or a particle filter.
12 . The system of claim 11 , wherein the state estimator uses one or more model selected from: battery pack geometry model, sensor model, electrical components model, thermal transport model, battery cell heat generation model, battery cell heat transport model, equivalent circuit model, or battery cell electrochemical model.
13 . The system of claim 12 , wherein the model is a parameterized model, wherein the parameterized model is parameterized as a function of one or more of: temperature, current, voltage, resistance, state of charge, battery age, time, or combinations thereof.
14 . The system of claim 10 , wherein determining the operating conditions further comprises determining operating conditions that improve an accuracy or observability of the state of the battery.
15 . The system of claim 14 , wherein operating conditions that improve an accuracy or observability of the state of the battery comprise operating the battery in a slow cycle mode or current pulsed mode.
16 . The system of claim 10 , wherein the system further comprises a remote computing system configured to:
receive battery states from a plurality of batteries;
generate operating instructions across the plurality of batteries based on the battery states from the plurality of batteries and an optimization goal; and
transmit the operating instructions for the battery to the processor.
17 . The system of claim 10 , wherein the operating instructions comprise one or more battery operation condition selected from:
charging rate;
discharging rate;
charging voltage;
depth of discharge range;
operating temperature;
operating voltage;
storage temperature;
storage voltage;
battery operating lifetime;
accumulated charge at a given voltage load; and
total charge throughput.
18 . The system of claim 17 , wherein when the operation instructions comprise a change in one battery operation condition, subsequent operation instructions for the battery do not comprise a change in the one battery operation condition.
19 . The system of claim 17 , wherein determining the operation instructions comprises evaluating at most five of the battery operating conditions.