Precharge Resistors in Japanese and Korean New Energy Vehicles and Energy Storage Systems

In recent years, the Japanese and Korean markets for new energy vehicles (EVs) and energy storage systems (ESS) have continued to expand. The stability requirements for precharge protection components in high-voltage platforms, battery management systems (BMS), and on-board inverters are constantly increasing. During high-voltage startup and DC-Link capacitor charging, instantaneous surge currents can significantly impact IGBT modules, capacitors, and control circuits. Therefore, highly reliable precharge resistors are gradually becoming key protection components in EV power systems.

Especially in the Japanese and Korean markets, customers are paying more attention to long-term stability under high-temperature environments, insulation performance, and compact installation structures to adapt to the increasingly integrated electronic layout of new energy vehicle platforms.

A Korean new energy vehicle power system integrator needed to find ceramic precharge resistors suitable for continuous charge and discharge conditions for its EV inverter and BMS project.

Customer application environments primarily involve:

• EV high-voltage battery systems
• DC-Link precharge circuit
• On-board inverter start-up protection
• High-temperature continuous operation environment

Due to limited system platform space, customers also require products with multiple terminal structures to adapt to different installation orientations and connection methods.

To address customer application needs, we offer a 45W/60W Automotive Ceramic Precharge Resistor solution, employing ceramic encapsulation and wire-wound structure design to enhance thermal stability and surge withstand capability under high-voltage conditions.

• Power range: 45W / 60W
• Resistance range: 20Ω–120Ω
• Impulse voltage: 335V–500V / 1s
• Insulation withstand voltage: DC3000V / 60s
• Leakage current: <1mA
• Temperature withstand capability: Up to 200°C
• Multiple terminal structures available

During the EV high-voltage start-up phase, this product effectively limits instantaneous surge current, reducing the impact on the inverter system and BMS control module during the initial capacitor charging stage.

During sample testing and system verification, the customer focused on the product's stability under high-temperature and continuous start-up conditions.

In practical applications, this ceramic precharge resistor maintained a stable resistance output and exhibited low leakage current during high-voltage precharge. Its DC 3000V insulation withstand voltage also met the customer's design requirements for the safety of high-voltage platforms in new energy vehicles.

Furthermore, the multi-terminal structure simplifies the installation process and is suitable for compact EV electronic system layouts. The customer ultimately applied this product to their new energy vehicle inverter precharge module and some energy storage system projects.

As the Japanese and Korean new energy vehicle and energy storage markets continue to demand higher voltage safety and system reliability, ceramic wirewound precharge resistors are becoming crucial protection components in EV and ESS systems.

Compared to ordinary power resistors, the ceramic wirewound precharge resistor, with its high insulation withstand voltage, strong thermal stability, and high surge withstand capability, is more suitable for applications such as high-voltage start-up, capacitor precharge, and inverter protection.

For EV and energy storage system engineers, the selection process should focus on impulse voltage capability, insulation performance, operating temperature range, and terminal structure compatibility to meet the requirements for long-term stable operation under complex conditions.