Nexisense ZC61 Vehicle Hydrogen Leak Sensor: Integrated Safety Monitoring Solution for Hydrogen Fuel Cell Vehicles and Hydrogen Refueling Stations

Hydrogen Safety Incident Warning and Core Monitoring Requirements

The recent hydrogen fuel cell bus explosion at a hydrogen refueling station in Chungju, North Chungcheong Province, South Korea (December 23, 2024) resulted in three severe injuries. The vehicle involved was a Hyundai Elec City FCEV model. The accident occurred shortly after engine startup, triggering an emergency inspection and partial suspension of operation of 147 hydrogen buses nationwide in South Korea. This incident exposed potential leakage and ignition risks in hydrogen systems (fuel cell stack, pipelines, valves, and hydrogen storage containers) during the startup phase after refueling. It once again highlights the engineering challenges caused by hydrogen’s low molecular weight, high diffusivity, and wide explosion limit (4%–74.2% vol).

Hydrogen, as a highly efficient clean energy source (with water as the primary combustion product), is accelerating its adoption in transportation sectors such as FCEVs, hydrogen heavy trucks, and hydrogen buses. However, the entire industry chain (hydrogen production, storage, transportation, refueling, and utilization) faces a leakage-accumulation-explosion risk chain. China’s National Energy Administration “Medium and Long-Term Plan for the Development of the Hydrogen Energy Industry (2021-2035)” clearly lists safety as a core element and requires the establishment of a full-chain risk prevention and control system. As a key sensing component, the Nexisense ZC61 hydrogen leak sensor supports vehicle domain controllers and hydrogen station safety interlocks through real-time concentration monitoring and rapid response, and has proven reliability in hydrogen vehicles and infrastructure.

Application Scenarios: Hydrogen Vehicles and Hydrogen Infrastructure

The ZC61 sensor optimizes MEMS catalytic combustion detection technology for the high permeability characteristics of hydrogen small molecules and is suitable for:

• Multi-point monitoring of hydrogen supply pipelines and fuel cell stack compartments in hydrogen fuel cell passenger cars, buses, and heavy trucks

• Leakage early warning at onboard hydrogen storage cylinder valve interfaces and hydrogen cooling circuits

• Fixed monitoring of high-pressure pipelines, hydrogen nozzle interfaces, compressor rooms, and hydrogen storage tank areas in hydrogen refueling stations

• Ventilation failure or accumulation risk prevention in hydrogen production, storage, and transportation facilities

• Safety systems for emerging hydrogen applications such as hydrogen ships, drones, and forklifts

The sensor withstands automotive-grade vibration (compliant with ISO 16750), wide temperature range (-40~85℃), and EMC requirements (CISPR 25 Class 3). Redundant deployment supports ASIL B-D level functional safety.

Selection Guide: ZC61 Key Parameters and Matching Principles

Selection must match hydrogen system pressure levels, monitoring thresholds (typical alarm at 1% vol and shutoff at 2% vol), interface requirements, and environmental conditions.

ZC61 Hydrogen Leak Sensor Main Parameters:

• Detection principle: MEMS catalytic combustion

• Measurement range: 0~4% vol (0~100% LEL)

• Resolution: 0.01% vol

• Accuracy: ±5% FS (typical)

• T90 response time: ≤10 s

• Output: CAN 2.0B / LIN / UART / Analog

• Power supply: DC 9~36 V

• Protection: IP67, anti-H2S poisoning, anti-electromagnetic interference

• MTTF: >10 years, AEC-Q100 compatible

For FCEV onboard applications, CAN/LIN versions are recommended for integration into the vehicle network; for fixed monitoring at hydrogen stations, UART + Modbus conversion is recommended to achieve remote SCADA integration. Intelligent algorithms support temperature and humidity compensation, reducing cross interference and zero drift.

System Integration Considerations and Compatibility Assurance

Engineering integration focuses on protocol compatibility, installation position, response chain, and diagnostic capability.

• Communication protocol: CAN supports 500 kbps with complete DBC files, enabling easy integration into VCU/BMS or hydrogen station PLC; LIN/UART is suitable for low-cost nodes.

• Installation deployment: For vehicles, install in high hydrogen leakage risk areas (cylinder valves, stack compartment bottom, pipeline joints) with explosion-proof ventilation; in hydrogen stations, install at elevated positions to capture rising hydrogen.

• Power supply and EMC: Wide voltage input with built-in TVS and filtering, meeting ISO 7637 pulse testing.

• Thresholds and linkage: Supports multi-level thresholds (warning 1%, alarm 2%, interlock hydrogen cutoff/ventilation), integrated UDS diagnostics (ISO 14229) enabling OBD functions.

• Multi-sensor fusion: Combined with pressure, temperature, and micro-water sensors to form hydrogen system health monitoring, supporting edge algorithm anomaly filtering and cloud trend analysis.

In actual projects, RS485/LoRa gateways can achieve multi-point networking in hydrogen stations, while vehicle CAN bus load rate should be controlled below 70%.

Project Application Case Sharing

• Domestic hydrogen fuel cell bus demonstration line: ZC61 multi-point sensors were deployed in the hydrogen system and hydrogen refueling station of 18-meter hydrogen buses, connected to the vehicle controller via CAN. This achieved minute-level alarms for leaks below 1% vol and automatic ventilation/hydrogen shutoff. The system has operated for more than two years without false alarms and supports regional hydrogen demonstration evaluations.

• Mass production support for hydrogen heavy trucks: Integrated with fuel cell systems, sensor data is used for hydrogen line health monitoring and predictive maintenance, reducing the probability of hydrogen leakage incidents and helping vehicles pass the GB/T 24549 safety standard.

• Hydrogen refueling station safety upgrade project: ZC61 sensors were fixed in hydrogen storage areas and around hydrogen nozzles, connected to the station control system via Modbus. This enabled concentration trend monitoring and ventilation interlocks, complying with the “Technical Specification for Hydrogen Refueling Stations”.

These applications verify the stability and rapid response of the ZC61 under high hydrogen concentration transients, vibration, and electromagnetic environments.

OEM Customization and Bulk Supply Advantages

Nexisense supports OEM/ODM cooperation with hydrogen vehicle manufacturers, fuel cell system suppliers, and hydrogen equipment manufacturers:

• Customized range, alarm thresholds, interface protocols (CAN ID/baud rate), shape, and installation interfaces

• Provision of SDK, A2L files, functional safety documentation, and integration reference designs

• Strict batch consistency in mass production with full AEC-Q level environmental reliability verification

• Stable supply chain and framework agreements matching new vehicle SOP schedules and hydrogen station construction timelines

Suitable for large-scale deployment requirements in the hydrogen industry chain.

Frequently Asked Questions (FAQ)

1. How is cross interference controlled when ZC61 operates in high humidity and trace H2S environments? MEMS components include anti-poisoning coatings and filters. When H2S <50 ppm, the impact is <5%. Humidity compensation algorithms maintain zero drift <±0.02% vol/year.

2. Can the sensor response time meet T90≤10 s in low-temperature environments (-30℃)? Wide-temperature design and low-power heating support rapid startup at -40℃, with preheating <30 s, meeting hydrogen system rapid leak detection requirements.

3. How can CAN bus integration avoid multi-node address conflicts and communication delays? Configurable CAN IDs and priorities are supported. Recommended bus load rate is <70%, with heartbeat monitoring and DM1/DM2 diagnostics ensuring network health.

4. How should sensor placement be optimized in hydrogen stations to capture rising hydrogen? Install at elevated positions (2~3 m above ground), combined with CFD simulation to place sensors above leak sources and in ventilation dead zones, supporting multi-point array coverage.

5. How are calibration cycles and traceability requirements for hydrogen project acceptance met? Zero/span calibration is recommended every 6–12 months. Nexisense provides CNAS traceable reports compliant with GB/T 29729 and local hydrogen safety standards.

6. Compared with traditional electrochemical hydrogen sensors, what are the advantages of ZC61 catalytic combustion technology? Strong anti-poisoning capability, longer lifespan (>10 years), faster response, and no oxygen dependency, making it suitable for long-term continuous monitoring in vehicles and hydrogen stations.

7. What technical support and spare part response mechanisms are available after bulk procurement? 7×24 hotline support is provided. Standard spare parts are stocked, with emergency replacements shipped within 48 hours. Framework customers can sign spare consignment and on-site calibration agreements.

8. How should the total cost of ownership (TCO) of ZC61 be evaluated in hydrogen vehicle systems? Calculate based on procurement cost, calibration frequency, MTTF >10 years, and integration cost. Typical TCO is 25–35% lower than comparable imported products due to high reliability and localized service.

Conclusion:

Nexisense is committed to providing high-performance hydrogen leak monitoring core components and complete solutions for hydrogen vehicle manufacturers, fuel cell system integrators, and hydrogen station builders. If your organization is advancing hydrogen bus/heavy truck mass production, hydrogen infrastructure upgrades, or hydrogen demonstration projects, please contact us for sample testing, technical solution discussions, or bulk quotations. Together we can strengthen the safety foundation of the hydrogen industry chain and promote the development of green low-carbon transportation.