Abstract: Systems and methods are disclosed for estimating state parameters of lithium manganese iron phosphate (LMFP) battery cells with improved accuracy and robustness. Per-cell estimation of state of charge (SOC) and state of health (SOH) is performed using electrical measurements including voltage, current, and temperature. In example implementations, shifts in characteristic voltage transition regions associated with manganese- and iron-based redox reactions are monitored to infer degradation during normal operation. Mechanical swelling force of the battery cell is measured using one or more pressure sensors, providing a physical indicator correlated with SOC and long-term lithium inventory loss, particularly in voltage-flat operating regions. Direct current internal resistance values obtained from controlled current pulses may further enhance estimation accuracy.

Abstract: The present disclosure provides a circuit for balancing voltages of battery packs to be connected in parallel, comprising: IN-side switches and OUT-side switches; a DC-DC converter with an IN terminal connected to the IN-side switches and an OUT terminal connected to the OUT-side switches; and a controller to operate an IN-side switch to connect a Vmax battery pack to the IN terminal, operate an OUT-side switch to connect a Vmin battery pack to the OUT terminal, and activate the DC-DC converter to transfer energy from the Vmin battery pack to the Vmin battery pack. The controller responds to an IN terminal voltage being sufficiently close to a voltage of a first battery pack by operating an IN-side switch to connect the first pack to the IN terminal, and responds to an OUT terminal voltage being sufficiently close to a voltage of a second battery pack by operating an OUT-side switch to connect the second battery pack to the OUT terminal.

Abstract: The present disclosure provides a circuit for balancing voltages of battery packs to be connected in parallel, comprising: IN-side and OUT-side switches; a DC-DC converter with an IN terminal connected to the IN-side switches and an OUT terminal connected to the OUT-side switches; and a controller to operate an IN-side switch to connect a Vmax battery pack to the IN terminal, operate an OUT-side switch to connect a Vmin battery pack to the OUT terminal, and activate the converter to transfer energy from the Vmax pack to the Vmin pack. The controller responds to an IN terminal voltage being sufficiently close to a first battery pack voltage by operating an IN-side switch to connect the first pack to the IN terminal, and responds to an OUT terminal voltage being sufficiently close to a second battery pack voltage by operating an OUT-side switch to connect the second pack to the OUT terminal.