A method of thermal management of a battery

A thermal management device for a battery, wherein the battery comprises at least one cell and wherein the thermal management device comprises a heating device configured to heat the battery in response to a heating instruction, and a controller, wherein the thermal management device is configured to:

• determine a state of charge of the cell;
• determine a cell current of the cell;
• determine a first value of a first parameter of the heating device;
• determine a reference cell temperature of the cell;
• determine a maximum cell temperature and a minimum cell temperature of the cell by comparing the cell current and the first value of the first parameter to test data associating calibration values of the cell current and first parameter with one or more temperature errors;
• and
• use the reference cell temperature, an ambient temperature, and a heat transfer coefficient of the heating device to determine a temperature of the heating device, and use the temperature of the heating device to determine a second value of the first parameter of the heating device;
• wherein in an event that:
• the maximum cell temperature is below a first threshold temperature;
• the minimum cell temperature of the cell is below a second threshold temperature;
• and
• the state of charge of the cell is above a threshold state of charge;
• the thermal management device is further configured to instruct the heating device to heat the cell.