Modern EV owners who plug into a fast charger on a cold morning without preparing the car first may notice slower charging. Setting the charger as a destination in the vehicle's navigation lets many EVs use the drive time to warm the battery, a step Tesla's manual instructs owners to take 30 to 45 minutes before arrival. Porsche warns that skipping the routine can result in lower charging power. This pre-conditioning is part of the thermal management system fitted to most modern EVs.
That system typically includes a cooling loop that pumps liquid coolant through tubes or metal plates pressed against the battery, absorbing heat and moving it to a radiator or into the air conditioning circuit. Fleet management company Geotab tracked more than 22,700 EVs for a study and found batteries lost an average of 2.3 percent of their health each year. Cars in hot climates lost about 0.4 percentage points more annually than those in mild climates, and cars that frequently used fast chargers above 100 kW lost 3 percent a year versus 1.5 percent for those that rarely did. At the average rate, a battery would still hold roughly 77 percent of its health after a decade.
Fast charging can push 300 amps or more through the pack, generating substantial waste heat that must be removed. A 2021 review in the journal Energies found that a temperature difference of more than 5 degrees Celsius across a cell can accelerate aging by 25 percent, so a capable cooling system must keep the entire pack balanced and regulated. Cold creates different problems: internal resistance rises, and fast charging a cold battery can cause lithium plating, a metallic lithium buildup on the cell's electrodes that worsens as temperatures fall. Recurrent, which studied more than 30,000 US EVs, found batteries averaged 78 percent of their ideal range at freezing temperatures and about 70 percent at -7 degrees Celsius, with cabin heating accounting for roughly two-thirds of the extra energy an EV uses in the cold.
The original Nissan Leaf of 2010 used passive air cooling for its 24 kWh pack, while Tesla, GM and Ford used liquid systems. Leaf owners in Phoenix tested 12 cars from the 2011 and 2012 model years and found range losses; Nissan said the issue affected fewer than 0.3 percent of US models, according to MIT Technology Review in 2012. The third-generation Leaf Nissan unveiled in 2025 finally adopted a liquid-cooled 75 kWh battery. According to Energies, liquid cooling needs two to three times less energy than air to hold a pack at the same temperature, which is why most EVs now use it.
Some automakers have taken different routes. BMW's i3 engineers skipped the coolant loop and ran refrigerant from the air conditioning directly to the battery. McLaren went further with its Speedtail, submerging all cells in electrically insulated oil, a step it called a first for a production road car; simulations cited in the Energies review found immersion cooling could move heat up to three times better than cooling plates.
A coolant loop is usually tied to a radiator for light loads and, through a heat exchanger, to the air conditioning for heavier duties such as fast charging. Nissan's system switches between the two modes and routes heat from the charger into the battery during home charging, a feature the newer Leaf uses to warm the pack. Tesla's Model Y uses a valve nicknamed the Octovalve to move coolant among the motors, battery and electronics, as Jalopnik found after an engineering teardown, and Tesla is exploring a patent on running the drive motor inefficiently on purpose so its waste heat can warm the battery. General Motors says its Ultium heat pump gathers waste heat from the battery, power electronics and passengers' bodies to warm the cabin, adding around 10 percent more range. China has introduced rules requiring new EVs to show their batteries do not catch fire or explode when a cell enters thermal runaway, a requirement that depends on a pack's cooling and insulation stopping heat from spreading to other cells.
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