Thermo-Galvanic Voltage Offset Subtraction in BMS Pulse Relaxation Telemetry
Subtracting thermo-galvanic voltage offsets from post-pulse relaxation telemetry prevents state-of-charge drift and protects battery warranty diagnostics.
Thermogalvanic Potential
Meaning
Voltage difference created in an electrochemical system when a temperature gradient is applied across the electrolyte and electrodes. Thermogalvanic potential results from the temperature dependence of the entropy of the ions in solution. This phenomenon can be used to convert waste heat into small amounts of electrical energy.
Voltage Variation
Magnitude of the effect depends on the type of ions present and the concentration of the electrolyte. In most commercial batteries, the thermogalvanic potential is small but measurable during periods of uneven heating. Designers must account for this shift to avoid errors in state of charge estimation.
Thermal Gradient
Presence of a hotter electrode relative to a colder one drives the migration of ions within the cell. This movement creates a steady state potential that lasts as long as the temperature difference is maintained. If the gradient is removed, the thermogalvanic potential dissipates as the system returns to thermal equilibrium.
Energy Recovery
Specialized cells are being developed to capture low grade heat from industrial processes using this principle. These devices operate as heat engines with no moving parts by cycling the temperature of the electrodes. While the power density is low, the ability to harvest energy from existing thermal losses provides a pathway for improving overall system efficiency in large installations.