Battery management system for an electric air vehicle
A battery management system and method for performing a battery state and, optionally, health parameter observation is disclosed, in particular, cell state-of-charge (SOC) observation, with two redundant, independent and dissimilar lanes. Specifically, a SOC determination in a first one of the lanes is based on Coulomb Counting. The other lane employs a different algorithm than Coulomb Counting. In some embodiments, a battery health observation is further performed independently by the two lanes, wherein the first lane employs an aging model and the other lane a different (dissimilar) algorithm. On the basis of state and health observation, state (state of function) of the battery system can be predicted to determine a range of flight in accordance with a predetermined flight profile.
1. A battery management system for an electric air vehicle, the battery management system being adapted to observe a current battery state-of-charge (“SOC”) of a battery system forming an energy storage system of the electric air vehicle, the battery management system comprising:
two redundant and dissimilar lanes for battery state determination, comprising:
a first lane of the two redundant and dissimilar lanes comprising equipment for determining a SOC of each individual battery cell of a plurality of battery cells of the battery system using a Coulomb Counting algorithm; and
a second lane of the two redundant and dissimilar lanes comprising equipment for determining the SOC of each individual battery cell of the plurality of battery cells of the battery system using a different mechanism than the Coulomb Counting algorithm, wherein:
each of the two redundant and dissimilar lanes further comprises equipment for determining a battery health parameter of each individual battery cell of the plurality of battery cells;
the determination of the battery health parameter by the first lane is based on an ageing model that determines the battery health parameter based on an observed utilization, the observed utilization including current, voltage, and temperature measured by the equipment for determining the battery health parameter of the first lane of the two redundant and dissimilar lanes; and
the determination of the battery health parameter by the second lane is based on a different mechanism than the ageing model.
2. The battery management system according to claim 1 , wherein cell impedance or cell capacity of each individual battery cell is used as the battery health parameter.
3. The battery management system according to claim 1 , wherein the equipment for determining the battery health parameter of the first lane comprises equipment for measuring the current, the voltage and the temperature of each individual cell.
4. The battery management system according to claim 1 , wherein the second lane uses a model-based SOC estimation algorithm.
5. The battery management system according to claim 1 , wherein the equipment for performing the SOC determination using the Coulomb Counting algorithm in the first lane comprises: equipment for determining charging currents for each individual cell of the plurality of battery cells constituting the battery system during ground operation and equipment for determining overall load currents of each individual cell.
6. The battery management system according to claim 5 , wherein the equipment for performing SOC determination using the Coulomb Counting algorithm in the first lane further comprises: processing circuitry for calculation of a state-of charge based on the determined charging currents and overall load currents of each individual cell.
7. The battery management system according to claim 1 , wherein the equipment for determining the battery health parameter of the second lane comprises: equipment for measuring at least one of the current, the voltage and the temperature of each individual cell of the plurality of battery cells of the battery system.
8. The battery management system according to claim 1 , wherein the electric air vehicle is an electric vertical take-off and landing aircraft (eVTOL).
9. A battery management method of observing a current battery state-of-charge (“SOC”) and battery health of a battery system forming an energy storage system of an electric air vehicle, the battery management method comprising the steps of:
determining SOC of each individual battery cell of a plurality of battery cells of the battery system using a mechanism that is based on a Coulomb Counting algorithm;
independently determining SOC of each individual battery cell of the plurality of battery cells of the battery system using a different mechanism than the Coulomb Counting algorithm;
determining a battery health parameter of each individual battery cell of the plurality of battery cells based on a mechanism using an ageing model that determines the battery health parameter based on an observed utilization, the observed utilization including current. voltage, and temperature; and
independently determining the battery health parameter of each individual battery cell of the plurality of battery cells based on a different mechanism than the ageing model.
10. The method according to claim 9 , wherein cell impedance or cell capacity of each individual battery cell is used as the battery health parameter.
11. An electric air vehicle comprising a battery management system, the battery management system adapted to observe a current battery state-of-charge (“SOC”) of a battery system forming an energy storage system of the electric air vehicle, the battery management system comprising:
two redundant and dissimilar lanes for battery state determination, comprising:
a first lane of the two redundant and dissimilar lanes comprising equipment for determining a SOC of each individual battery cell of a plurality of battery cells of the battery system using a Coulomb Counting algorithm; and
a second lane of the two redundant and dissimilar lanes comprising equipment for determining the SOC of each individual battery cell of the plurality of battery cells of the battery system using a different mechanism than the Coulomb Counting algorithm, wherein:
each of the two redundant and dissimilar lanes further comprises equipment for determining a battery health parameter of each individual battery cell of the plurality of battery cells;
the determination of the battery health parameter by the first lane is based on an ageing model that determines the battery health parameter based on an observed utilization, the observed utilization including current, voltage, and temperature measured by the equipment for determining the battery health parameter of the first lane of the two redundant and dissimilar lanes; and
the determination of the battery health parameter by the second lane is based on a different mechanism than the ageing model.
12. The air vehicle according to claim 11 , wherein cell impedance or cell capacity of each individual battery cell is used as the battery health parameter.
13. The air vehicle according to claim 11 , wherein the second lane uses a model-based SOC estimation algorithm.
14. The air vehicle according to claim 11 , wherein the equipment for performing the SOC determination using the Coulomb Counting algorithm in the first lane or the second lane comprises equipment for determining charging currents for each individual cell of the plurality of battery cells constituting the battery system during ground operation and equipment for determining overall load currents of each individual cell.