High Voltage Coolant Heater (HVCH) for Electric Bus

High Voltage Coolant Heater (HVCH), commonly known as High Voltage PTC Water Heater, is a high-voltage, high-power, water-cooled PTC heater specifically designed for new energy buses (pure electric/hybrid). Its core uses high-voltage electricity to heat antifreeze, which is then used to provide cabin heating, battery preheating, and windshield defrosting through the fluid circuit. It is the core component of bus thermal management.
1、 Core Definition and Positioning
Full name: High Voltage Coolant Heater (HVCH), High Voltage Water Heating PTC
Purpose: To replace traditional engine waste heat and provide winter heating, battery preheating, and windshield defrosting for pure electric/hybrid buses
2、 Working principle (PTC water heating cycle)
High voltage power supply: The bus high-voltage battery (400-800V DC) supplies power to HVCH, with low voltage 24V control.
PTC heating: The internal PTC ceramic core generates heat when electrified (self limiting temperature, ≤ 120 ℃).
Heating coolant: PTC heat is transferred to the flowing antifreeze (50% ethylene glycol), which heats up to 60-85 ℃.
Circulating heating: water pump driven hot water circulation:
Cabin warm air → warm air core → blower blows hot air
Battery preheating → Battery liquid cooling plate → Maintain optimal temperature of 15-25 ℃
Windshield defrosting → defrosting core → melting frost
Constant temperature self limiting: PTC temperature rises → resistance suddenly increases → power automatically decreases, without the need for additional temperature control, preventing dry burning and non ignition.
3、 Core Advantage (Bus Scenario)
✅ High power, fast heating: 15-20 kW, cabin temperature can reach 20 ℃+in 3-5 minutes, and can be started in extreme cold (-30 ℃).
✅ Multi functional and highly integrated: simultaneously providing heating air, battery preheating, and defrosting, simplifying the thermal management system.
✅ Safe and reliable, suitable for passenger cars: PTC self limiting temperature, no open flame, dry burning non combustible; IP67、 Vibration resistance and long lifespan (≥ 10000h).
✅ Energy saving and battery friendly: about 20% more energy-efficient than air heated PTC; Preheating the battery improves low-temperature endurance by 20-30%.
✅ Compatible with high-voltage platforms: 600V mainstream, compatible with new 800V models, and in compliance with high-voltage safety standards for buses.
4、 Mainstream application scenarios (new energy buses)
Pure electric city bus: standard configuration of 15-20kW HVCH, winter heating+battery insulation.
Hybrid/extended range buses: auxiliary heat source to maintain heating and battery temperature when the engine is stopped.
Bus in high-altitude regions: Dual HVCH (2 × 15kW=30kW), capable of withstanding extreme cold temperatures of -40 ℃.
Hydrogen fuel cell bus: Preheat the fuel cell system to ensure low-temperature start-up.