Overview
In the thermal management system of new energy vehicles, electric pumps and cooling fans are responsible for regulating the temperature of the battery, motor, electronic control system, and cabin air conditioning system. Because pump and fan systems typically include motor drive modules, ECU control units, CAN/LIN communication interfaces, and various sensor interfaces, their internal electronic components are exposed to various electrical risks.
Semiware provides comprehensive EMC protection solutions for pump and fan systems in new energy vehicles, helping customers improve the reliability of automotive electronic systems.
I. The Important Role of Pump and Fan Systems in New Energy Vehicles
- Battery Thermal Management
When the BMS (Battery Management System) detects that the battery temperature exceeds the set range, it controls the electric pump and cooling fan to operate, reducing the battery temperature through coolant circulation and air exchange.
- Motor and Electronic Control System Heat Dissipation
The drive motor and power electronic modules of new energy vehicles generate a large amount of heat during operation.
The electric pump and cooling fan quickly dissipate this heat through coolant circulation and airflow, ensuring stable motor operation.
3. Air Conditioning and Cabin Heat Exchange
The air conditioning system of new energy vehicles not only needs to regulate the interior temperature but also participates in the thermal management of the battery and drive system.
The pump and fan system optimizes the overall vehicle thermal management by controlling the flow of the cooling medium.
II. EMC Challenges Faced by Pump and Fan Systems in New Energy Vehicles
2.1 ESD Threats to Communication Interfaces
CAN, LIN, and automotive Ethernet typically connect to external wiring harnesses via connectors.
During production, maintenance, and vehicle use, connectors may be subjected to:
- Human Body Model
- Contact Discharge
- Air Discharge
Therefore, low-capacitance ESD protection devices need to be added to the communication interface.
2.2 Transient Interference Generated by Motor Drives
Both pumps and fans are driven by motors. Motors are inductive loads, and voltage spikes and switching noise are generated during start-up, stopping, and PWM speed regulation, which may affect the stable operation of the MCU.
Therefore, multi-level protection using MOSFETs and TVS diodes is required.
2.3 Power Input Surge Risk
12V/24V power systems may be affected by load dumps and ISO 7637 transient pulses. Therefore, TVS diodes are usually required at the power input for overvoltage protection.
III. Semiware ESD Protection Solutions
Semiware offers a variety of automotive-grade ESD protection devices for different interfaces in pump and fan systems.
3.1 Automotive Ethernet ESD Protection
Automotive Ethernet features high-speed transmission, placing high demands on the parasitic capacitance of protection devices.
Recommended devices:
| Part Number | Working Voltage | Channel | Capacitance | ESD Capability | Package |
| GBLC03CI | 3.3V | 1 | 0.6pF | ±30kV Air / ±30kV Contact | SOD-323 |
| SRV05-4 | 5V | 4 | 0.6pF | ±15kV Air / ±8kV Contact | SOT-23-6L |
3.2 CAN / FlexRay Protection Solutions
Recommended devices:
| Part Number | Working Voltage | Channel | Capacitance | ESD Capability | Package |
| TPSE23T35B24B (SMC24Q) | 24V | 2 | 50pF | ±30kV Air / ±30kV Contact | SOT-23 |
| TPSE3D35B24A (SD24CQ) | 24V | 2 | 24pF | ±30kV Air / ±30kV Contact | SOD-323 |
3.3 LIN Interface Protection Solutions
Recommended devices:
| Part Number | Working Voltage | Channel | Capacitance | ESD Capability | Package |
| PESD1LIN | 15V/24V | 1 | 13pF | ±15kV Air / ±8kV Contact | SOD-323 |
3.4 Sensor Interface ESD Protection
| Part Number | Working Voltage | Capacitance | ESD Capability | Package | Application |
| SE5D15B3.3A | 3.3V | 15pF | ±30kV Air / ±30kV Contact | SOD-523 | 3V sensor protection |
| SE10F10B3.3A | 3.3V | 12pF | ±30kV Air / ±30kV Contact | DFN1006-2L | 3V sensor protection |
| SE10F10B5.0A | 5V | 15pF | ±25kV Air / ±25kV Contact | DFN1006-2L | 5V sensor protection |
| SE5D10B5.0AH | 5V | 25pF | ±30kV Air / ±30kV Contact | DFN1006-2L | 5V sensor protection |
IV. Semiware MOSFET Solution: Improving Fan Drive Reliability
New energy vehicle fan control systems typically use MOSFETs as motor switching devices.
When selecting MOSFETs, the following should be considered:
- Low on-resistance RDS(on)
- Low gate charge Qg
- High current capability
- Good thermal performance
Semiware recommends the following N-channel MOSFETs:
| Part Number | VDSS | ID | RDS(on) Max | Vth Max | Qgd | Package |
| SNM70N04G | 40V | 60A | 6mΩ | 2.2V | 2nC | DFN5×6-8L |
| SNM016N04G | 40V | 178A | 1.8mΩ | 2V | 13nC | DFN5×6-8L |
| SNM009N04GL | 40V | 200A | 0.8mΩ | 2.5V | 25nC | DFN5×6-8L |
V. TVS and EMC Comprehensive Protection Recommendations
In addition to ESD protection for communication interfaces, it is recommended to add protection in the following locations for pump and fan systems in new energy vehicles:
a. DC power input - TVS diode
Function:
- Suppress surges
- Prevent load dump damage
b. Motor drive circuit - TVS+MOSFET multi-level protection
Function:
- Absorb back EMF
- Reduce switching noise
c. Control signal interface - ESD diode
Function:
- Improve communication stability
Semiware has a professional laboratory that provides automotive electronic device testing, application verification, and protection solution selection support, helping customers select appropriate ESD, TVS, and MOSFET devices according to their actual system requirements.
Conclusion
By rationally designing ESD protection, EMC solutions, and selecting power devices, the reliability and lifespan of the thermal management system of new energy vehicles can be effectively improved.
Semiware provides automotive-grade ESD protection devices, TVS diodes, MOSFETs, and customized EMC solutions. We have a professional laboratory that provides automotive electronic device testing, application verification, and protection solution selection support to help customers build more stable and secure electronic systems for new energy vehicles.
For protection solutions for new energy vehicle pumps, fan systems, or other automotive electronic interfaces, please contact the Semiware engineering team for professional support.
