Meaning
Thermal process involves the generation of joule heat in the battery terminals due to high current flow during charging or discharging. In high-power applications, tab heating can raise terminal temperatures significantly above the core cell temperature. The process is most critical during rapid acceleration or fast-charging phases.
Controlling this localized heating is essential to protect the cell seals and prevent degradation.
Physical Mechanism
Current passing through the resistance of the metal tabs generates heat proportional to the square of the current. This localized heat source raises the temperature of the nearby electrode materials. If the tabs are not cooled, the heat flows inward, creating significant internal thermal stress.
This flow can damage the polymer seals that protect the cell from leaks.
Cooling Solution
Thermal designs often incorporate active cooling plates that make direct contact with the tabs. This contact removes the heat at the source before it can penetrate the interior of the cell. Designers use thermally conductive but electrically insulating materials to ensure safety.
This localized cooling allows the battery to operate at higher continuous currents.
Supplier Evaluation
Sourcing teams prioritize cells that demonstrate low terminal resistance and minimal heat generation. This evaluation involves measuring the temperature rise at the tabs under maximum continuous load. Selecting cells with superior terminal design reduces the complexity of the pack’s cooling system.
This choice lowers manufacturing costs and improves safety.
