Excessive heat can damage the essential electronic equipment that keeps electric vehicles (EVs) operating properly. That’s why the question facing all EV original equipment manufacturers (OEMs) is how to keep the batteries in these vehicles cool. While most current vehicles are cooling their batteries with water-glycol systems (similar in nature to cooling traditional internal combustion engines), the practice can lead to potential safety issues. 

Submerging the battery in a dielectric cooling fluid, a process known as “immersion cooling,” is where the cutting-edge OEMs and Tier One Suppliers  are currently focusing their attention for the future. Though currently in use only in race cars and some niche applications to date, the goal is to bring immersion cooling to mass production vehicles between 2025 and 2027. 

The question EV OEMs are facing to bring this technology into the mainstream is this: Will “off-the-shelf” dielectric cooling fluids be able to meet the growing needs of performance and safety? Or will it take partners to customize dielectric fluids into truly bespoke immersion cooling fluids to meet specific hardware requirements? 

Why Custom Formulation Matters 

Most industry suppliers use off-the-shelf base fluids and chemicals to formulate their dielectric fluids. Unfortunately, these fluids were not purposely designed for EV applications and cannot deliver the same levels of performance as custom-formulation approaches. 

Customized fluids frequently emerge from collaborative projects between fluid technology developers and OEMs/Tier One Suppliers. What makes them more effective is that they can be optimized for specific systems. Customization also allows the flexibility necessary to adapt as new EV battery hardware is developed and brought to market. 

In addition, custom formulators can tweak chemistries and additive packages during the formulation process to optimize the fluid’s performance properties. Currently, a number of OEMs and Tier One Suppliers (such as thermal management specialists and other EV equipment suppliers) are working through this complex process. 

What Can Be Customized? 

If the fluid technology partner has the right experience, there are multiple areas in which the fluid can be customized, including the following: 

• Electrical conductivity: It is critical to properly dial in the electrical conductivity of immersion fluids to avoid the potential for electrostatic discharge, which can damage the delicate equipment in an EV’s motor.
• Water management: Water can increase electrical conductivity, so immersion fluids must be formulated to avoid allowing water to infiltrate the system.
• Viscosity: Most EV manufacturers are looking for low-viscosity fluids to cool motor parts easily but lowering the viscosity too much can lead to increased fluid volatility. Volatile fluids are more easily combustible and can lead to battery fires. 

Learn about Lubrizol's EVOGEN™ thermal management fluids

Our View

As immersion cooling becomes more common in EV applications, the fluid formulations to enhance the performance and safety of the battery thermal management systems will also evolve. It will be incumbent on fluid technology developers to be flexible enough to leverage their chemistries and formulation “know-how” in partnership with leading EV OEMs to design and optimize the battery thermal management fluids necessary to maximize the potential of this emerging technology. 

For more information on immersion cooling, contact us or visit the Electrification section of Lubrizol360.