High security NTC Temperature Sensors :The Safety Sentinel for EV Charging Guns

Industry Context:

With the growing adoption of low-carbon mobility, electric vehicle production has surged, driving increased demand for home charging guns. These guns connect to public or home charging stations to transmit current to vehicle batteries. However, rising demand has intensified industry focus on thermal safety. NTC temperature sensors are integrated into charging guns to monitor real-time temperature changes at the contact points between the gun head and vehicle socket to ensure secure charging. This enables early detection of abnormal heat caused by high-power charging or poor contact, triggering alerts or power cuts to prevent overheating incidents. Below, we detail the working principles of charging guns and NTC sensors:

Ⅰ.Working Principle of Charging Guns

As critical charging equipment for EVs, portable charging guns convert household AC (220V) into DC power compatible with vehicle batteries. Their structure comprises several key components:

• Charging Gun Head: The core interface that physically connects to the EV’s charging port to transmit electricity.
• Control Box: Acts as the “intelligent hub,” dynamically regulating current and voltage during charging for stable output.
• Power Cable: Draws electricity from household outlets and delivers it to the control box and gun head, forming a complete circuit.
• NTC Temperature Sensor: As the “safety guardian,” it continuously monitors temperature across the gun head, cables, and control box. It triggers protection mechanisms upon detecting abnormalities to prevent hazards.

Ⅱ.Impacts of Overheating in Charging Guns

Heat generation primarily stems from increased resistance at contact points (gun head-socket interface). Massive current flow amplifies resistive heating during high-power DC fast charging, causing a significant temperature rise.

The safe operating temperature for EV charging guns is typically set below 60°C, a threshold balancing safety and stability. Exceeding 60°C risks:

• Reduced charging efficiency or interruptions
• Accelerated component aging
• Potential safety hazards (e.g., fire risk, battery damage)

Thus, maintaining temperatures within the ≤60°C range is critical.

Ⅲ.How NTC Temperature Sensors Safeguard Charging Guns

Safety is paramount during EV charging. Abnormal temperature spikes can damage cables, cause charging failures, or even ignite fires. While vehicle systems activate power-cut protection, NTC sensors provide the first line of defense:

1. Real-Time Temperature Monitoring

After plugging in, current flows continuously from the charger to the battery. During prolonged high-power charging, heat builds at the gun-socket interface. Embedded NTC sensors detect internal temperature changes, transmit signals to the monitoring module, and report real-time data to the charger’s central controller, enabling precise thermal oversight.

2. Multi-Level Protection Mechanism

When temperatures exceed safety thresholds, the system activates layered safeguards:

• Stage 1 Response: At 65°C, the charging current automatically reduces to minimize heat generation.
• Stage 2 Protection: Cooling fans engage at maximum speed if temperatures keep rising to enhance heat dissipation.
• Final Defense: At 85°C (mandatory threshold per GB standards), power is cut immediately to terminate charging and eliminate risks.

Conclusion:

As the EV industry evolves, charging safety requirements will escalate. With their reliable monitoring and critical protective functions, NTC temperature sensors will inevitably see broader and deeper adoption across the sector.