PUBLISHER: ResearchInChina | PRODUCT CODE: 1907919
PUBLISHER: ResearchInChina | PRODUCT CODE: 1907919
Policy and Regulation Drive: Promoting the Development of Electric Vehicle Thermal Management Systems towards Environmental Compliance, Active Safety Protection, and Thermal Runaway Management
According to the "National Plan for China's Implementation of the Montreal Protocol on Substances that Deplete the Ozone Layer (2025-2030)", China will fully strengthen the management of ozone-depleting substances (ODS) and hydrofluorocarbons (HFCs), synergistically address ozone layer depletion and climate change, and promote the green, low-carbon, and high-quality development of related industries. For the first time, HFCs used in automotive air conditioning have been included in the scope of control, with relevant provisions including:
By January 1, 2029, the usage of HFCs for controlled purposes shall be reduced by at least 10% of the baseline value, and priority will be given to carrying out reduction activities in key industries such as automobiles, home appliances, and commercial refrigeration and air conditioning.
Starting from July 1, 2029, the automotive industry shall prohibit the use of refrigerants with a GWP (Global Warming Potential) greater than 150 in the air conditioning systems of newly declared M1 category vehicles; it is encouraged to carry out research and development and application of natural refrigerant substitution technologies in the field of electric vehicle thermal systems.
Standardize the prevention of refrigerant leakage and recycling management in the automotive industry, strengthen the supervision of refrigerant recovery during automobile maintenance, and ensure refrigerant recovery during the dismantling of end-of-life vehicles.
Study the inclusion of requirements for the use and leakage control of automotive air conditioning refrigerants in the next phase of motor vehicle emission standards.
In accordance with the national plan, passenger cars must fully switch to refrigerants with a GWP below 150 by 2029. In the future, multiple technical routes will develop in parallel, including natural refrigerants represented by carbon dioxide (R744) and propane (R290), as well as various low-GWP mixed refrigerants. At present, the domestic refrigerant is still dominated by R134a, which will rapidly switch to the next-generation refrigerant driven by policies, leading to the iterative upgrading of relevant components of the automotive thermal management system, such as electric compressors, refrigerants, pipelines, and pressure devices.
Currently, most of the relevant standards for domestic automotive thermal management systems are aimed at traditional automotive thermal management systems and components, while standards related to electric vehicle thermal management systems are constantly being improved. A large number of new electric vehicle thermal management standards were issued in 2025, promoting the development of electric vehicle thermal management systems towards environmental compliance, active safety protection, and thermal runaway management.
"Motor Vehicle Engine Coolant": A mandatory technical specification in China's national standard system, consisting of two parts: GB 29743.1 (Fuel vehicle engine coolant) and GB 29743.2 (Electric vehicle coolant). GB 29743.1-2022 was issued on December 29, 2022, and implemented on July 1, 2023, replacing the original GB 29743-2013 standard. The new national standard GB 29743.2-2025 "Motor Vehicle Coolant - Part 2: Electric vehicle coolant" was issued on March 28, 2025, and officially implemented on October 1. Led by the Ministry of Transport, this standard, targeting the characteristics of high-voltage circuits in electric vehicles, for the first time clarifies that the electrical conductivity of the coolant must be <= 100 μS/cm, and strengthens performance requirements such as corrosion resistance and thermal stability, reducing the risk of battery short circuits and thermal-runaway from the source.
"Rubber Hoses and Tubing for Cooling Systems": Current national standard GB/T 18948-2017 "Rubber hoses and tubing for cooling systems for internal-combustion engines-Specification" was formulated mainly to meet the needs of traditional fuel vehicles, and insufficiently considers the special requirements of new energy vehicle cooling systems. The technical requirements for testing in this standard can no longer meet the development needs of the current automotive industry in many aspects, especially in the two key indicators of electrical performance and flame-retardant performance. For example, if the rubber hoses in the cooling system of an electric vehicle do not have sufficient flame-retardant performance in the event of a collision or battery failure, a fire may break out quickly, causing serious consequences. Insufficient electrical performance may lead to failures of the electrical system, affecting the safe operation of the vehicle. GB/T 18948-2025 has been issued, changing the standard name to "Rubber hoses and tubing for cooling systems for automotives-Specification". Based on the 2017 version, it adopts ISO 4081:2016 with modifications and extends to electric vehicles, with a planned implementation date of March 1, 2026.
New National Standard for Power Batteries "Electric vehicles traction battery safety requirements" (GB 38031-2025): This standard was issued in 2025 and will be officially implemented on July 1, 2026. For models that have obtained type approval, the implementation time of the standard is slightly later, on July 1, 2027. This means that the design goal of the Battery Management System (BMS) has fully shifted from "temperature control" to "safety protection", and its performance requirements have been raised to an unprecedented level.
1.Ultimate balance between heat dissipation and thermal insulation performance: The new national standard requires that the temperature of the battery pack must be controlled below 60°C without catching fire after thermal runaway. This requires the thermal management system to have ultra-efficient heat transfer capacity to cope with the huge heat released instantly during thermal runaway. At the same time, to prevent thermal propagation, excellent thermal insulation materials (such as high-performance aerogel, foam, etc.) must be used between cells and modules to block heat transfer. The system needs to upgrade from "heat dissipation-oriented" to an integrated solution of "precision temperature control, rapid heat dissipation, and efficient thermal insulation".
2.New requirements for the performance of thermal management fluids/coolants: As a key medium of the thermal management system, coolants need to meet more stringent performance indicators:
Higher heat dissipation efficiency: To meet the extreme heat dissipation needs during thermal runaway.
Stronger insulation: The new national standard improves the insulation resistance requirements. As a medium in contact with live components, the insulation reliability of the coolant is crucial.
Better stability and compatibility: It needs to adapt to the higher operating temperature brought by fast charging, and remain stable without leakage or performance degradation when the battery is hit.
3.Promote the evolution of thermal management technical routes: To meet the new requirements, traditional solutions such as indirect liquid cooling may face challenges. Technical routes such as immersion cooling, which can achieve direct contact between cells and coolants with higher heat transfer efficiency, are becoming important development trends due to their faster response to temperature changes and higher safety factors, although their costs are relatively higher. At the same time, solid-state batteries are generally considered to naturally meet the requirements of "no fire and no explosion" due to the non-flammable and high-temperature resistant characteristics of their solid electrolytes. The implementation of the new national standard will accelerate their industrialization process.
Environmentally Friendly Refrigerants for Automotive Air Conditioning: OEMs are Accelerating the Introduction of New Refrigerants to Meet Low-GWP Requirements and Adapt to the Global Market
In accordance with the national plan, passenger cars must fully switch to refrigerants with a GWP below 150 by 2029. In the future, multiple technical routes will develop in parallel, including natural refrigerants represented by carbon dioxide (R744) and propane (R290), as well as various low-GWP mixed refrigerants.
New refrigerants are evolving from the previously commonly used R11, R12, R134a, R1234yf, etc., to low-GWP refrigerants such as R290 and R744, including a transition phase compatible with different refrigerants. In the short to medium term, mixed refrigerants may be a possible solution path (such as R290 mixed with R134a or R1234yf, a transition plan to meet regulatory, technical, and cost requirements).
R290 small-scale/modular heat pumps: R290 (propane) is a natural refrigerant with extremely low environmental impact (ODP=0, GWP≈3), belonging to class A3 highly flammable refrigerants. After leakage, it is easy to form a flammable mixture within a certain concentration range, thus putting forward higher requirements for the sealing, explosion-proof, and leakage monitoring of the system. R290 is relatively more suitable for small-scale, closed application scenarios where the charge amount and ventilation path can be strictly controlled. For example, exploring R290 local heating (with strictly controlled charge amount and leakage monitoring) in small loops such as the cabin/steering wheel/seats as an energy efficiency enhancement method for the vehicle thermal management. At the same time, introducing blended refrigerants such as R1234yf and R134a into the R290 main line can cover medium and low-temperature working conditions or platforms more sensitive to cost/supply chain, which has gradually become a key promotion direction of the industry.
R744 (carbon dioxide) heat pumps: Among the existing main alternative options, R744 (carbon dioxide) is currently the only refrigerant route that can meet the medium and long-term regulatory requirements of the three major markets simultaneously, realizing "one system, global access", and may become a long-term development route. However, the cost of R744 (carbon dioxide) heat pumps will increase significantly, and the technical difficulty is relatively large, making it difficult for OEMs to introduce them quickly in short term.
OEMs are accelerating the introduction of new refrigerants to meet the low-GWP requirements at the regulatory level and based on adapting to the global market.
Taking Li Auto as an example, its next-generation thermal management system lays out two directions simultaneously: the R290 (propane) system and the carbon dioxide (R744) system.
R290 (propane) system:
Advantages: R290 has better performance at low temperatures than the traditional R134a refrigerant and is more environmentally friendly. Its refrigeration capacity is strong, up to 13.6kW, far exceeding the demand for fast charging in summer.
Challenges and solutions: The main disadvantage of R290 is its flammability. To this end, Li Auto's design solution is to significantly reduce the refrigerant charge to a minimum, from about 2 kilograms of refrigerant in the traditional R134a system to only 0.2 kilograms. At the same time, by highly integrating the liquid storage tank, intermediate heat exchanger, and pipelines, safety is improved to facilitate collision prevention and leakage prevention.
System characteristics: The system adopts three six-way valves, which can realize up to 22 working modes. Both refrigeration and heating rely on the same system. The heat source comes from the water-cooled condenser, and the cold source comes from the Chiller (battery cooler).
Carbon dioxide (R744) system:
Advantages: The carbon dioxide system has the best low-temperature heating performance, saving about 40% of energy compared with the R134a system during heating, and the heat pump heating power can reach 8kW.
Challenges: Its high-temperature performance is limited because the critical temperature of carbon dioxide is relatively low, only 31°C.
Tier1 Suppliers Intensively Launch Next-Generation Thermal Management Integrated Modules and Electric Compressors
With the emergence of new environmentally friendly refrigerants with zero ODP and low GWP (<=4) such as R744 (carbon dioxide), R290, and R1234yf as alternatives for automotive refrigerants, changes in refrigerants will lead to adjustments in the design of compressors, including scroll strength, torque bearing, sealing methods, and control strategies, which require targeted upgrades to ensure system reliability and energy efficiency.
The electric compressors of new energy vehicles have achieved a functional leap from single temperature regulation to multi-system collaborative intelligent management, and are key components for vehicle energy efficiency. The technical trends of automotive electric compressors are mainly reflected in the following aspects: high efficiency and energy saving, breakthrough in low-temperature heating technology, system integration, refrigerant substitution, material upgrading, and structural optimization.
Tier1 suppliers adopt a dual main line for refrigerant routes and have launched a series of new products such as integrated modules and compressors in 2024-2025:
One is the alpine high-efficiency heat pump route centered on CO2 (R744), emphasizing efficient heating capacity even under extremely cold conditions such as -35°C;
The other is the natural refrigerant high-efficiency route represented by R290, which has the advantages of low charge, high energy efficiency, and low carbon, and is accelerating vehicle application verification. Synchronously, heat pump systems and integrated modules (including valve islands, plate heat exchangers, and controllers) are being promoted collaboratively to form a systematic supply of "compressors + thermal management modules", meeting the multi-objective optimization of vehicle energy efficiency, comfort, and energy supplement efficiency.
With the continuous progress of technology, in the future, the efficiency of vehicle thermal management system will be higher and more complex. The refrigerant side (agent side) and water side will be integrated, and the overall development will be in the direction of integration.
The integrated thermal management agent-side component adopts a design concept without air conditioning pipes, integrating air conditioning components including compressors, electronic expansion valves, WCC (water-cooled condensers), Chillers (battery coolers), and receiver driers into one module, reducing refrigerant pipelines, lowering refrigerant charge, and improving system safety and efficiency.
The integrated thermal management water side (coolant circuit) component, with sensible heat transport as the core, serves the battery, motor/electronic control, cabin heating, etc., and realizes multi-circuit coupling and waste heat recovery through electronic water pumps, multi-way valves, water-cooled condensers (WCDC), Chillers, radiators, etc.
Midea Welling has launched an indirect heat pump integration solution, realizing deep coupling of the thermal fields of the passenger compartment, battery compartment, and electric drive compartment through refrigerant-side integrated design, and intelligently distributing heat to improve energy efficiency. Through topological architecture innovation, multi-motor integrated electronic architecture, and algorithm optimization, this module not only shortens the development cycle of vehicle thermal management but also conforms to the trend of the next-generation vehicle electrical architecture.