EV Thermal Management

BTMS · heat pump · chiller · valves

The thermal system decides how fast an EV can charge, how much range it keeps in winter and how long the pack lasts. Valves and pumps now matter as much as cells.

Diagram of an integrated EV thermal system. A refrigerant loop using R1234yf or R744 carbon dioxide, with an HV compressor, condenser, evaporator and expansion valves, sits at the top. It couples down to a chiller, which pulls heat from coolant, and to the cabin HVAC. Below, a multi-way coolant valve routes heat between the battery loop (cold plates, pump, PTC heater, temperature target set by the BMS) and the powertrain loop (inverter, motor, DC-DC converter, onboard charger), whose waste heat can warm the pack. INTEGRATED EV THERMAL SYSTEM: THREE LOOPS, COUPLED Refrigerant loop (R1234yf or R744 CO2) HV compressor, condenser, evaporator, expansion valves Chiller pulls heat from coolant Cabin HVAC evaporator, heater, defrost Multi-way coolant valve routes heat between battery and powertrain loops Battery loop cold plates, pump, PTC heater BMS sets target temperature Powertrain loop inverter, motor, DC-DC, OBC waste heat can warm the pack
Valve leader
Sanhua (China)
Tesla design
Octovalve, Model Y
HV loads
compressor, PTC heater
Companies tracked
21, 6 Chinese
Hub
Supply Chain

Finding

Fast-charge speed, winter range and pack life are all set by the thermal system, and Chinese suppliers now lead its valves, pumps and integrated modules

DC fast charging is usually limited by cell temperature, not charger power: the pack must be preconditioned warm before a session and chilled during it. Tesla's Octovalve (Model Y, 2020) showed that one multi-way valve and a heat pump could replace separate battery, motor and cabin circuits, and most new EV platforms now follow that integrated pattern.

The battery thermal management system (BTMS) is the pack-level subset: cold plates or channels, thermal interface material, pumps, valves, a chiller interface, heaters and sensors, all tightly coupled to the battery management system (BMS). The vehicle thermal system is the wider architecture that shares heat exchangers and valves across battery, powertrain and cabin. In most current designs the battery loop is one branch of that wider system.

Supply is concentrated. Sanhua Intelligent Controls and Yinlun lead electronic expansion valves, multi-way valves and thermal modules out of Zhejiang, and Tuopu supplies integrated thermal modules to Tesla. Global incumbents are Denso, Hanon Systems (Korea), MAHLE, Valeo, Modine and Marelli, with Webasto and Eberspächer in PTC heaters and Dana and Modine in cold plates. BYD builds its own through FinDreams. Volkswagen's MEB platform offered an R744 (CO2) heat pump; most other platforms use R1234yf, which faces pressure from proposed EU PFAS restrictions.

Partition

Battery thermal management vs the vehicle thermal system

Two meanings of TMS, and where control sits.

Battery vs vehicle thermal management
SubsystemPrimary purposeMain componentsInterfacesTypical naming
Battery thermal managementKeep cells in a safe, uniform temperature window; enable fast charging and cold-weather powerCold plates or channels, TIM, pumps, valves, chiller interface, heaters, sensorsTightly coupled to the BMS; interacts with charging control and the VCUBTMS, battery loop, pack thermal system
Vehicle thermal system (integrated)Optimize heat flow and efficiency across battery, powertrain and cabinHeat pump or AC compressor, condensers, evaporators, radiators, chillers, multi-way valves, pumps, manifoldsBMS, VCU, HVAC controller, sometimes central computeIntegrated thermal system, vehicle TMS, thermal architecture
Thermal controllerRun pumps and valves and arbitrate between loopsDedicated thermal ECU or a function on a zonal or central computerCAN or CAN FD; Ethernet in centralized designsThermal control unit, thermal ECU

Hardware

Thermal system hardware and who makes it

Mechanical and electrical content, HV and LV loads, and leading suppliers by component.

TMS bill of materials
ComponentFunctionBattery relevanceHV/LV roleLeading suppliers
Coolant pumpsCirculate coolant through loopsMoves heat in and out of cold platesLV load; reliability-criticalBosch, Pierburg (Rheinmetall), Aisin, Sanhua
Valves (expansion and multi-way)Direct coolant and refrigerant flowRoutes battery cooling and heatingLV actuation; enables integrated loopsSanhua, Dunan, Yinlun, Vitesco, Denso
Heat exchangers (radiator, chiller, condenser, evaporator)Move heat to air or between loopsBattery chilling through the chillerSets cooling capacity and efficiencyDenso, MAHLE, Valeo, Hanon, Modine, Yinlun
Electric compressor / heat pumpMoves heat through the refrigerant cycleStrong battery cooling and preconditioningHV load; largest thermal power drawHanon, Denso, Sanden (Hisense), Aotecar, MAHLE
Heaters (PTC and HV coolant heaters)Add heat for cabin and packWinter performance and fast-charge preheatingHV load; costs rangeWebasto, Eberspächer, BorgWarner
Cold plates, channels, TIMMove heat from cells and electronics into coolantDrives temperature uniformity and safetyMechanical integration in pack and inverterDana, Modine, ESTRA, Henkel, Parker
Sensors (temperature, pressure, flow)Measure loop conditionsEnables derating and safe controlFeeds diagnostics and protectionSensata, TE Connectivity, Amphenol
Integrated thermal modulesPumps, valves and exchangers in one manifoldCuts hoses, leaks and assembly timeSingle harness and controllerTuopu, Sanhua, Yinlun, Hanon, Valeo

Vendors

Thermal management suppliers

Global suppliers by component, with plant countries.

Battery and vehicle thermal management suppliers
CompanySegmentProductsHQPlantsTechnologyCustomersStatus
AisinPumpsElectric water pumpsJapanJapan, US, ChinaElectric pumpsToyotaactive
AotecarCompressors and heat pumpsElectric compressorsChinaChinaElectric scroll compressorsChinese automakersactive
BorgWarnerHeatersHigh-voltage coolant and cabin heatersUSGermany, China, USHV heatersNot disclosedactive
BoschPumpsElectric coolant pumps and thermal modulesGermanyGermany, ChinaElectric pumpsNot disclosedactive
BYDOEM system designIntegrated heat pump with direct refrigerant cooling of Blade packsChinaChinaDirect refrigerant coolingBYD, Denza, Yangwang, Fangchengbaoactive
DanaHeat exchangers and cold platesBattery cold plates and heat exchangersUSCanada, US, Mexico, EuropeCold platesNot disclosedactive
DensoCompressors and heat pumpsHeat pumps, electric compressors, heat exchangersJapanJapan, US, ChinaR1234yf heat pumpsToyota, Lexusactive
Dunan EnvironmentValves and integrated modulesElectronic expansion valvesChinaChinaValvesChinese automakersactive
EberspaecherHeatersHigh-voltage coolant heatersGermanyGermany, ChinaHV PTC heatersEuropean automakersactive
Hanon SystemsCompressors and heat pumpsElectric compressors, heat pumps, thermal modulesSouth KoreaSouth Korea, China, Hungary, Mexico, USR1234yf and R744 heat pumpsHyundai, Kia, Ford, Volkswagen Groupactive: Hankook Tire took control, January 2025
HenkelThermal interface materialsGap fillers, thermal adhesives and coatings for packsGermanyGermany, US, ChinaThermal interface materialsPack makersactive
MAHLECompressors and heat pumpsThermal modules, compressors, chillers, battery cooling platesGermanyGermany, China, Mexico, USIntegrated thermal modulesEuropean and US automakersactive
ModineHeat exchangers and cold platesBattery thermal systems (EVantage) for commercial and off-highway vehiclesUSUS, Mexico, Europe, ChinaChillers, heat exchangersCommercial vehicle and bus makersactive
Pierburg (Rheinmetall)PumpsElectric coolant pumpsGermanyGermany, Czech Republic, ChinaElectric pumpsEuropean automakersactive
Sanden (Hisense)Compressors and heat pumpsElectric compressorsJapanJapan, China, PolandElectric scroll compressorsNot disclosedactive: Majority owned by Hisense since 2021
Sanhua Intelligent ControlsValves and integrated modulesElectronic expansion valves, multi-way valves, integrated modulesChinaChina, Mexico, PolandValves and integrated modulesTesla, BYD and most Chinese automakersactive: Global leader in EV thermal valves
TeslaOEM system designOctovalve and Supermanifold heat-pump system (Model Y onward)USUS, China, GermanyIntegrated refrigerant and coolant loopsTeslaactive
Tuopu GroupValves and integrated modulesThermal management modules and heat-pump assembliesChinaChina, Mexico, PolandIntegrated modulesTesla, Chinese automakersactive
ValeoCompressors and heat pumpsHeat pumps including R744 systemsFranceFrance, China, Czech RepublicR744 and R1234yf heat pumpsEuropean automakersactive
WebastoHeatersHigh-voltage coolant heaters and battery thermal systemsGermanyGermany, China, USHV PTC heatersCar, bus and truck makersactive
YinlunHeat exchangers and cold platesHeat exchangers, chillers, battery cold platesChinaChina, US, MexicoHeat exchangers, cold platesChinese and US automakersactive

Sources

Sources and scope

Scope
EV Thermal Management Systems
Sources
OEM and supplier disclosures; ElectronsX electrical dataset
Updated
October 2026