Understanding the need of custom fluids for electric vehicle applications

Total Energies recently launched the new EV Fluid ranges in India for electric & hybrid cars and electric bikes, which have been developed specifically for drivetrain reducers, e-motors, e-transmissions and batteries in electric vehicles.

To understand more about the relevance of EV-specific fluids and how they are different from regular fluids for ICE vehicles, we got in touch with Mr Syed Shakilur Rahman, CEO Lubricants South Asia, TotalEnergies Marketing India Private Limited.

How are EV-specific fluids different from regular fluids for ICE vehicles?

To understand the difference between conventional ICE fluids and EV Fluids, we need to understand the difference in the lubrication regime between IC Engine and Electric Engine.

ICE functions on power generated by the combustion of fuel with numerous movable parts, which involves multiple metal-to-metal contacts. Hence, the lubrication of an IC Engine requires a specific tribological regime (tribology –  science of wear, friction and lubrication) which reduces friction between moving parts, prevents wear and tear, and removes impurities to ensure engine cleanliness along with heat dissipation properties.

Electric Engine or Electric motor functions on the electric power generated by the battery pack with 90% fewer movable parts as compared to ICE. Copper coils constitute the major part of the stator; hence copper compatibility of the oil becomes a key factor in selecting the right fluid. It is important that the fluid act as a dielectric liquid which becomes key to the prevention of electric charge build-up. EVs work on high RPMs, around 20,000, with a single reducer which demands better frictional control, wear protection and anti-foaming properties for the gearbox.

EV fluids are specially designed for the new age Electric and Hybrid vehicles to ensure optimum mileage, enhanced power, less charging time, and most importantly, safety of the vehicles.

Please tell us about the different fluids needed in an electric vehicle.

In an electric vehicle, we need fluid for lubrication of the reducer or transmission, cooling of the batteries and cooling and lubrication of wet electric motors.

Electric motor fluid – To cater to the new electrical, thermal and frictional constraints of the components of an EV motor, EV fluids are developed to provide superior thermal stability to dissipate heat generated by electrical components and have dielectric properties to prevent static charge build-up, along with material compatibility.

Immersive cooling of batteries – Charging time of the batteries is a big constraint in developing the charging infrastructure. Battery immersed in an EV fluid can help reduce the charging time by increasing the charging potential of the onboard charger, which supplements fast charging. This also eliminates the risk of battery explosions in road accidents. EV fluids work as a safety enabler for the EV, which conventional fluids fail to achieve.

Advanced reducer fluid – EV Fluids are developed with enhanced frictional properties to protect gears from wear and tear. Anti-foaming properties help reducers to operate at very high RPMs.

Our Quartz EV fluids are designed based on component-level application. EV Drive MP is dedicated to liquid-cooled electric motors wherein the dielectric properties of the EV Fluid prevent short circuits, and static charge build-up, material compatibility with copper etc. Quartz EV Drive R is an EV Fluid for gearbox that provides protection of gears against wear and tear while achieving higher instant torque values.

How will these fluids impact the performance of EVs?

EV Fluids impact various performance parameters of Electric Vehicles as mentioned below:

• Liquid-cooled batteries will help enhance the charging potential of on-board chargers and decrease charging time.
• Improved safety of EVs with immersive cooling technology, which prevents heat-build up, and dielectric properties, which prevents short circuits, thus eliminating the risks of fire in an EV.
• Improved efficiency of the electric motor to withstand large quantum of electric power to achieve high torque level and peak power.
• Increased efficiency of reducer, withstanding higher RPMs by protecting the gears from wear and tear and foaming/de-aeration tendencies.
• Enhanced durability of electronic components.

Any analysis on how much the performance will be improved?

In one of the recent studies at our research centre, we decided to replace the battery cooling system in a plug-in hybrid with an immersion cooling alternative. In performance terms, the result was immediate: faster charging, better cooling, enhanced safety and lower cost and mass, without in any way needing to modify the design of either the battery or the vehicle. TotalEnergies has partnered with multiple OEMs and educational institutes to conduct performance studies of EV fluid on batteries, electric motors and transmission systems.