Battery management controllers and associated methods
A method for managing a plurality of batteries that are electrically coupled together includes (1) monitoring respective voltages of the plurality of batteries and (2) in response to a respective voltage of a first battery of the plurality of batteries reaching a first threshold value at a first time, reducing a charge or discharge rate of the first battery, relative to at least a second battery of the plurality of batteries. Charge and discharge rates may be adaptively managed such that each battery reaches the first threshold value at substantially the same time.
1. A method for managing a plurality of batteries that are electrically coupled together, the method comprising:
(a) monitoring respective voltages of the plurality of batteries;
(b) in response to a respective voltage of a first battery of the plurality of batteries reaching a first threshold value at a first time, reducing a charge or discharge rate of the first battery relative to at least a second battery of the plurality of batteries at least partially by changing operation of a first power converter electrically coupled to the first battery independently of operation of a second power converter electrically coupled to the second battery; and
(c) after step (b), adaptively managing charge or discharge rates of the plurality of batteries to reduce a difference in time between when (i) the respective voltage of the first battery reaches the first threshold value and (ii) a respective voltage of the second battery reaches the first threshold value.
2. The method of claim 1 , where the first and second power converters are electrically coupled in series.
3. The method of claim 1 , further comprising increasing a charge or discharge rate of the second battery to compensate for reducing the charge or discharge rate of the first battery.
4. The method of claim 3 , wherein increasing the charge or discharge rate of the second battery comprises changing operation of the second power converter electrically coupled to the second battery.
5. The method of claim 1 , further comprising increasing the respective charge or discharge rate of the first battery in response to a respective voltage of the second battery reaching the first threshold value at a second time that is after the first time.
6. The method of claim 1 , wherein adaptively managing charge or discharge rates of the plurality of batteries comprises changing a charge or discharge rate of the first battery relative to the second battery.
7. The method of claim 1 , wherein adaptively managing charge or discharge rates of the plurality of batteries comprises changing a charge or discharge rate of the second battery relative to the first battery.
8. The method of claim 1 , wherein adaptively managing charge or discharge rates of the plurality of batteries comprises using an iterative process to reduce the difference in time between when (i) the respective voltage of the first battery reaches the first threshold value and (ii) the respective voltage of the second battery reaches the first threshold value.
9. The method of claim 1 , wherein the respective voltages of the plurality of batteries comprise one of (a) actual battery voltages, (b) actual battery open circuit voltages, and (c) estimated battery open circuit voltages.
10. The method of claim 1 , wherein the first threshold value corresponds to one of (a) a knee in a battery voltage versus state of charge curve and (b) a knee in a battery voltage versus time curve.
11. The method of claim 1 , wherein the first threshold value corresponds to one of (a) a predetermined change in the respective voltage of the first battery and (b) a predetermined rate of change in the respective voltage of the first battery.
12. The method of claim 1 , wherein each battery is a battery module comprising either (a) a plurality of electrochemical cells or (b) a single electrochemical cell.
13. The method of claim 1 , further comprising adaptively managing charge or discharge rates of the plurality of batteries to reduce a difference in time between when (i) the respective voltage of the first battery reaches the first threshold value and (ii) a respective voltage of a third battery of the plurality of batteries reaches the first threshold value.
14. A method for managing a plurality of batteries that are electrically coupled together, the method comprising:
(a) monitoring respective voltages of the plurality of batteries;
(b) in response to a respective voltage of a first battery of the plurality of batteries reaching a first threshold value at a first time, reducing a charge or discharge rate of the first battery relative to at least a second battery of the plurality of batteries; and
(c) after step (b), adaptively managing charge or discharge rates of the plurality of batteries at least partially by using historical data from an energy storage system to determine how to adjust a charge or discharge rate of one or more of the plurality of batteries, to reduce a difference in time between when (i) the respective voltage of the first battery reaches the first threshold value and (ii) the respective voltage of the second battery reaches the first threshold value.
15. A controller for managing a plurality of batteries that are electrically coupled together, comprising:
one or more memories; and
one or more processors communicatively coupled to the one or more memories, the one or more processors being configured to execute instructions stored in the one or more memories to:
monitor respective voltages of the plurality of batteries,
in response to a respective voltage of a first battery of the plurality of batteries reaching a first threshold value at a first time, reduce a charge or discharge rate of the first battery, relative to at least a second battery of the plurality of batteries, and
adaptively managing charge or discharge rates of the plurality of batteries, at least partially by using historical data from an energy storage system, to reduce a difference in time between when (i) the respective voltage of the first battery reaches the first threshold value and (ii) a respective voltage of the second battery reaches the first threshold value.
16. The controller of claim 15 , wherein the one or more processors are further configured to execute instructions stored in the one or more memories to increase a charge or discharge rate of the second battery to compensate for reducing the charge or discharge rate of the first battery.
17. The controller of claim 15 , wherein the one or more processors are further configured to execute instructions stored in the one or more memories to increase the respective charge or discharge rate of the first battery, in response to a respective voltage of the second battery reaching the first threshold value at a second time that is after the first time.
18. The controller of claim 15 , wherein the one or more processors are further configured to execute instructions stored in the one or more memories to adaptively managing charge or discharge rates of the plurality of batteries to reduce a difference in time between when (i) the respective voltage of the first battery reaches the first threshold value and (ii) a respective voltage of a third battery of the plurality of batteries reaches the first threshold value.