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Automotive OEMs and Suppliers in Race to Set Standard for Thermal Management Modules
Thermal management is critical to the development of electric vehicles (EV). To be able to deliver on consumer expectations, automotive OEMs and their suppliers have been focusing on integrating thermal management controls for the cabin, electric motor, batteries and power electronics into one optimised modular system.
Waste heat in cars with internal combustion engines could be used for interior climate control. Electric vehicles (EV) need an independent heat control system. In EVs thermal management is decisive to the things that matter to the consumer; not only comfort, but also driving range and charging times. The travel distance provided by one battery charge can fall to below two-third when driving in cold winters compared to warm summer days. Fast charging requires battery cell temperatures to be held closely around the optimal of 40 degrees celsius.
The vehicle interior, batteries, electric motor and power electronics until recently all had their own separate heating and cooling systems. The trend now is to combine those into one optimised integrated system and make it modular for use on multiple vehicle platforms. Integrated Thermal Management Modules (ITMM) – or Vehicle Integrated Thermal Management (VITM) or many other acronyms for the same thing – consist of cooling fans, temperature sensors, control circuits, coolant loops, rotary valves and other parts all working in concert to achieve optimal performance.
A lot of investment and research & development activity is currently going into ITMM development. ‘We see established suppliers developing modules on their own or in cooperation with OEMs,’ says Isabelle Kraft, senior automotive analyst at market researcher Ducker Carlisle, ‘but we also see new suppliers developing by themselves. Established automotive suppliers are looking for a new business field because of the end of combustion engines.’
One of the market leaders in integrated thermal management on the OEM side is Tesla, with a heat pump system design around an ‘Octovalve’, a part that functions like a network router, taking heat from any component that needs cooling and providing it to any that needs heating. Five internal valve positions direct the flow of water-glycol coolant through all the loops to the cabin, motor, batteries, drive train, power electronics, control electronics. Octovalve is a clever design that eliminates dozens of separate components, pipes and connections still found in competitors’ solutions.
In addition to leading OEMs like Tesla, automotive parts manufacturers have been working independently on modular systems that they can sell to the OEMs. Hyundai WIA in January 2021 introduced the ‘first ever thermal management module that integrates EV driveline and battery parts’, based on four international patents and around thirty domestic patents for thermal management technology. Mass production was announced to start from 2023, with a full ‘Integrated Thermal Management System (ITMS)’ including the air conditioning system following by 2025.
Schaeffler began working on integrated thermal management with Audi around 2012 and now offers an advanced modular system of thermal management solutions for EVs, including a ‘4-in-1’ system that combines and optimises temperature controls for the vehicle interior, batteries, electric motor and power electronics. The system comprises heat sources and sinks and a coolant circuit with an Integrated Coolant System (ICS) with pumps, sensors and a valve to distibute coolant flows. The modules can be used in different combinations and adapted to various vehicle classes.
In the summer of 2023 Italian component manufacturer Marelli presented their new integrated Thermal Management Module (iTMM), claiming to improve efficiency, safety and driving range up to 20% and meeting the latest market requirements, including ultra-fast charging. The system modularises water-cooled heat exchangers, such as a chiller or water-cooled condenser, with what Marelli calls ‘a smart valve arrangement’. The integrated system reduces the number of required parts, with smaller size and weight, contributing to simplified manufacturing, design flexibility and general cost reduction.
The role of engine control units (ECU) or electronic control modules (ECM) and various types of integrated circuits (IC) has become much more central in electronic vehicles. Microcontrollers take temperature and other data from various sensors and send instructions to the different parts of the system such as coolant valves and mechatronic actuators. The semiconductor industry is a vital player in the development of integrated thermal management systems. Infineon has released an digital evaluation kit to support rapid prototyping of ITMS designs.
Beyond the similarities between solutions, there are still many different possible approaches that developers of thermal management modules could take. ‘Will it start directly with two loops? Which refrigurant will they use?’ Isabelle Kraft wonders. The standard has not been set yet. The field is still wide open. What will be done by the OEM and what by the supplier? Do suppliers need to invest in design and R&D? Or will the concepts come from the OEM, with the suppliers only building the modules? ‘Suppliers would need to start developing modules right now if they want to have a contract in the next year,’ Kraft warns.
Isabelle Kraft, senior automotive analyst at market researcher Ducker Carlisle, will speak on a session about Integrated Thermal Management Modules at the Thermal Management Expo, 5-7 December in Stuttgart.