As vehicles become electrified new components including batteries, power electronics, and electric motors are added which present new thermal challenges. Although battery electric vehicles eliminate an internal combustion engine and traditional transmission, their thermal and fluid systems can be even more complex to compensate for lost waste heat. Automakers are making different choices to balance performance and cost challenges to maximize thermal/fluid architecture value.
Tesla sets the benchmark for highly integrated vehicles, including thermal and fluid systems. Other manufacturers are taking different approaches to maximize value based on different assumptions and constraints.
Not all vehicles need high performance, higher cost, thermal fluid systems. For low cost BEVs and many hybrid vehicles simple air-cooling topologies are employed for battery thermal management and in some cases for electric machines and power electronics. For example, the SGMW Hongguang Mini BEV which can sell for less than $5000 can meet its mission and performance targets with passive cooling of the battery and drive systems with an optional air conditioner.
Tesla’s high-performance heat pump system includes complex functionality for both the coolant and refrigerant systems, to maximize charging rates and EV range. To minimize cost and maximize performance through waste heat recovery, Tesla has designed a highly integrated fluid system with coolant and refrigerant “supermanifolds”.
Volkswagen decided to focus on the refrigerant system functionality to maximize thermal management value for its MEB BEV platform vehicles. VW employs a relatively high-cost carbon dioxide refrigerant heat pump to improve low temperature range. In parallel, VW has a moderately complex coolant system for thermal conditioning of the battery and electric drive system.
Other manufacturers such as Mercedes (EQE/EQS), BMW (iX/i4), and Ford (Mustang Mach-e) are choosing to maximize value by focusing on coolant waste heat recovery. In this paradigm, coolant based thermal systems avoid high refrigerant circuit costs, but still allow significant waste heat recovery to extend EV driving range and enable faster DC battery charging.
Hyundai/Kia has implemented a coolant “superbottle” for the Kia EV6 and Ioniq 6, with similar function to a design used for the 2018 Tesla Model 3. This lower cost integrated coolant system solution is particularly attractive when a heat pump is optional. In such a design coolant system integration can be accomplished independent of the refrigerant system which may be simple, or complex if a heat pump system is installed.
BYD recently took a lower cost refrigerant centric approach for its standard heat pump developed for BEV3.0 platform vehicles. BYD chose refrigerant centric thermal integration, which is similarities to Tesla’s super manifold. The elegance of the BYD approach is a low-cost coolant system which can convey heat to the refrigerant system with one coolant pump and a simple coolant valve. The BYD design was enabled by refrigerant battery thermal management. Such coolant system simplification is not possible when coolant-based battery thermal management is employed. The result of BYD’s latest design is good performance and low cost.
Each approach described above has merits. Ultimately, ITB believes that thermal system value depends on driving down cost while meeting functional targets. Different approaches can make sense, but in the longer run balancing cost and performance is expected to lead to preferred designs. ITB projects that in the future fluid integration such as manifolds and “superbottle” modules will be standardized. What is not yet clear is whether coolant or refrigerant centric BEV thermal/fluid designs will win. Stay tuned.
ITB Provides Insights into Changing Vehicle Thermal/Fluid System Technologies and Markets
ITB surveys automakers and organizations throughout the automotive value chain to understand unmet needs and innovations for improved value. In our 2022 research, ITB dove deeply into designs and materials for fluid architectures, modules, and fluid components. Contact The ITB Group to learn more about changing technology markets, ITBs latest research reports, and how to influence our research.
