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Things are Hotting up When it Comes to EV Battery Cooling

As more and more drivers are making the switch from Internal Combustion Engine (ICE) vehicles to Electric Vehicles (EVs), consumer interest in the next generation of vehicles is gaining momentum. Common questions include “which models are suitable for longer commutes?” and “which models have longer lasting batteries?”

However, what about those potential buyers that live in warmer climates, such as Dubai or California, for example? Which models are suitable for summer in these regions? Which models are less susceptible to premature battery degradation?

Modern Lithium-Ion battery packs are robust, and more often than not, can outlive the life of the vehicle that they power. Yet, how long they last actually depends on how they are treated during their lifetime. When we talk about longevity, we are actually referring to how well a battery pack stores charge and how effectively it gives that charge back to a vehicle. Heat is the biggest threat to battery pack longevity. For example, when heat energy is added to a chemical compound, it can change how the bonds in that compound are made and can actually change the compound into something else. The same is true for EV batteries. When excessive heat is applied to a battery cell, it makes it harder for the cell to store electrons as effectively as it once could. Unfortunately, heat is unavoidable – pulling energy out of a battery pack at high currents causes a battery to heat up due to internal resistance in the pack. Thankfully, degradation by everyday use is negligible over the battery’s lifetime.

So what about EVs in hotter climates? Well, many electric vehicles feature liquid cooled battery packs, where cooling solutions are pumped through specially designed plates or channels embedded into or situated underneath battery cells. This technology enables battery packs to be kept warm in winter and cool in summer – maintaining optimal temperatures to minimise battery degradation. Liquid cooling is the preferred solution over air cooling, which involves ambient air being channelled over the battery while the car is moving or directed into battery packs via fans. In hot countries, in the peak of summer, air will be too warm to cool battery packs. Air cooling would simply accelerate battery degradation.

Source: Nikki Gordon-Bloomfield, Transport Evolved –  Hot Weather and EVs: Why Liquid Cooling is Best

It would appear that electric vehicles that utilise liquid cooling are the obvious choice for warmer climates. However, liquid immersion cooling takes thermal management to a whole new level. This emerging method of cooling involves battery cells being fully immersed in a dielectric coolant, such as MIVOLT. The non-conducting characteristics of MIVOLT allows this range of fluids to come into direct contact with battery cells, which is both a more effective method of heat removal and a lighter-weight option than those mentioned above, which rely on fans to divert air or pipework/cooling plates to conduct coolants.

Liquid immersion cooling will drive the future of electric vehicles and associated infrastructure.