State of Power

In a lot of battery applications the State of Power (SOP) is a key output from the BMS. This will take into account the State of Charge, State of Health and other parameters such as temperature.

How much power can the battery pack deliver for the next 10 seconds or 30 seconds?

DCIR and ohms law

Maximum Cell Discharge Capability

Establishing the maximum cell discharge capability is difficult without understanding the design in detail. However, you can work towards establishing this limit with a number of measurements and calculations.

As this is an estimation of power the maximum current capability and resistance are the key parameters to estimate so that the power limits can be established.

DCIR of a Cell

A battery cell is not a perfect current source as it also has anĀ internal resistance. This resistance changes as a function of temperature, SoC and SoH. It also changes depending on the previous charge/discharge cycling of the cell.