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Sensing Technology: Fastening the "Seat Belt" for New Energy Vehicle Batteries
In the context of the rapid development of the new energy vehicle industry, power batteries, as the core component, have safety performance that directly determines the safety level and market competitiveness of the entire vehicle. Whether it is the mature ternary lithium / lithium iron phosphate battery system or the rapidly emerging hydrogen fuel cell route, potential risks such as thermal runaway and gas leakage have always been the focus of B2B buyers. Nexisense focuses on the field of battery safety perception, providing full-chain support from sensor dies to system-level integration solutions, helping PACK manufacturers, OEMs, and BMS suppliers significantly improve the active safety capabilities of battery packs without significantly increasing costs.
Lithium Battery Thermal Runaway Early Monitoring Requirements and Technical Paths
Lithium-ion batteries (especially high-nickel ternary systems) are highly prone to thermal runaway under abuse conditions such as overcharge, overdischarge, internal short circuit, external compression/puncture. The thermal runaway evolution typically goes through four stages: self-heating → gas production → jetting → open flame/explosion. Among them, the gas production stage (mainly releasing CO, CO₂, VOC, H₂, CH₄ and other combustible/toxic gases) often appears 5-30 minutes in advance and is the most effective early warning window.
Nexisense lithium battery thermal runaway monitoring module adopts MEMS + electrochemical/NDIR composite process to achieve multi-dimensional real-time monitoring of CO (0-2000 ppm), CO₂ (0-5 vol%), VOC (0-2000 ppm) and temperature. Core advantages include:
Response time T90 < 15 s (CO/CO₂), superior to traditional single temperature monitoring
Cross-interference suppression < 5% (typical CO₂ influence on CO)
Built-in temperature/pressure compensation and ABC automatic baseline correction to ensure long-term zero drift < ±5% FS/year
CAN 2.0B / I²C / UART digital output, directly interfacing with mainstream BMS (Infineon, Renesas, NXP solutions)
Module size < 25×20×8 mm, power consumption < 150 mW, suitable for narrow space integration in high-voltage battery packs
Typical integration method: Deploy 1 monitoring point every 10-20 cells, collect data to the regional controller and upload to BMS via CAN bus to achieve composite criterion warning of “multi-point gas production + temperature anomaly”. Project actual measurement data shows that this solution can advance thermal runaway warning time by 8-15 minutes, buying valuable time for occupant evacuation and fire intervention.
Hydrogen Fuel Cell Gas Leakage and Safety Monitoring Solution
Hydrogen fuel cell systems typically operate at pressures of 35-70 MPa, and hydrogen leakage risks run through multiple links such as hydrogen filling port, hydrogen supply pipeline, stack, tail exhaust, etc. The lower explosion limit of hydrogen is only 4 vol%. Once leaked and encountering open flame or static electricity, it is extremely easy to cause catastrophic accidents.
Nexisense hydrogen safety monitoring module adopts high-sensitivity catalytic combustion/thermal conductivity/electrochemical composite principle, achieving fast response (T90 < 5 s) for hydrogen (0-4 vol% LEL range), while compatible with CO, CH₄ and other interfering gas suppression. Key characteristics:
Detection range 0-100% LEL, accuracy ±2% LEL
Anti-silicone poisoning, anti-H₂S interference design, suitable for long-term operation in hydrogen environment
Supports RS485 Modbus RTU / CAN FD output, convenient for interfacing with FCU (fuel cell controller) and vehicle domain controller
Protection rating IP67, resistant to -40~+85°C wide temperature, vibration compliant with ISO 16750-3 standard
Module integrates pressure/temperature composite monitoring to achieve dual criteria of “hydrogen concentration + pipeline pressure anomaly”
In actual projects, this module is often deployed near the hydrogen filling port, hydrogen bottle valve area, stack inlet/exhaust pipeline and under-vehicle sealed cabin to achieve full-coverage leakage monitoring. When the concentration reaches 1 vol% (25% LEL), level-1 warning is triggered (sound and light + forced hydrogen supply cut-off), and 2 vol% (50% LEL) triggers level-2 response (forced hydrogen exhaust + high-voltage power cut-off).
Selection Guide and Integration Considerations
Selection Key Points
Battery type: Ternary lithium prioritizes CO+CO₂+VOC composite monitoring, LFP can focus on CO₂+temperature; hydrogen fuel cell prioritizes high-sensitivity H₂ sensor + pressure composite.
Interface protocol: BMS with limited resources selects I²C/UART, domain controller integration prioritizes CAN FD, remote diagnostics selects Modbus RTU over RS485.
Range and accuracy: Thermal runaway gas production monitoring recommends CO 0-1000 ppm / CO₂ 0-2 vol%, hydrogen leakage prioritizes 0-4 vol% LEL range.
Installation environment: Inside battery pack prioritizes IP67 or above, anti-condensation version; hydrogen system pipeline area requires hydrogen embrittlement resistant materials.
Power consumption and size: High-voltage battery pack space constrained, prioritize<200 mW / <30×20 mm modules.
Integration Considerations
Sampling location: Gas sensors should be placed in cell gaps / above busbars where gas easily accumulates, avoid directly facing exhaust valves; hydrogen sensors installed downstream of high-risk leakage points.
Electrical compatibility: CAN bus recommends shielded twisted pair + 120 Ω terminating resistor, baud rate 500 kbps; RS485 bus length >10 m requires repeaters.
Warning strategy: Recommend “gas concentration + temperature rise rate + voltage anomaly” three-parameter fusion criterion, set multi-level thresholds + time hysteresis (typical >10 s) to suppress false alarms.
System verification: Recommend GB 38031-2020 thermal runaway triggering test, hydrogen leakage simulation diffusion test, verify warning time and BMS response consistency.
Long-term maintenance: Support OTA firmware upgrade and remote zero-point tracking, one field span calibration every 12 months.
Nexisense OEM/Customization and Bulk Supply Advantages
Nexisense provides full-chain OEM/ODM services from MEMS/electrochemical dies to complete monitoring modules, customizable according to customer PACK structure, cell type, BMS platform:
Flexible adjustment of gas types and ranges
Private protocol register mapping, alarm threshold solidification
Specific form factor interfaces (SMT/plug-in/waterproof connectors)
Firmware layer custom fusion algorithms and event reporting logic
Bulk supply (MOQ 5k) enjoys:
Supply chain locking and priority capacity guarantee
Batch-to-batch consistency verification (-40~+125°C 1000h temperature cycling + vibration + high humidity)
Accelerated life screening and factory report
8-12 week delivery response, meeting annual fixed-point project rhythm
Common Questions and Answers (FAQ)
1. How does the Nexisense lithium battery thermal runaway gas monitoring module achieve seamless integration with mainstream BMS?
The module supports standard CAN 2.0B protocol (including J1939 extension) and private ID configuration, baud rate configurable up to 1 Mbps, directly mapped to BMS diagnostic messages without additional gateway conversion. Already adapted to multiple Tier1 BMS platforms, integration cycle usually<4 weeks.
2. In high-nickel ternary battery packs, will CO₂ sensors be interfered by electrolyte volatilization?
Adopts NDIR dual-beam + dedicated optical filter design, cross-interference with electrolyte volatiles (carbonates)<3%, long-term zero drift controlled at ±8 ppm/year, verified by actual PACK aging tests.
3. How does the hydrogen fuel cell system hydrogen leakage sensor cope with high humidity and low temperature environments?
Selects moisture-resistant catalytic combustion element + built-in heating self-compensation, response time still<8 s at -40°C, no significant baseline drift at humidity 0-95%RH, meets GB/T 36282 hydrogen system safety requirements.
4. How to avoid excessive bus load and conflicts with multi-point gas monitoring data?
Supports programmable node addresses + multi-master arbitration mechanism, recommends using CAN FD or I²C multiplexer for expansion; single bus supports up to 32 nodes, data refresh cycle can be set to 100-500 ms.
5. Can bulk projects customize “gas production rate + temperature slope” composite warning algorithm?
Supported. Customers can provide thermal runaway test data, Nexisense algorithm team implements custom d[gas]/dt and dT/dt threshold logic at firmware layer, development cycle 6-10 weeks, including MIL-STD-810G environmental verification.
6. How does the module ensure EMC and insulation performance in high-voltage battery pack environments?
Internal full shielding design + TVS array protection, external interface withstand voltage >2.5 kV, radiation/conducted emission meets CISPR 25 Class 3, insulation resistance >100 MΩ@500 VDC, has passed vehicle-level EMC testing.
7. After thermal runaway warning, how to link with other vehicle systems (such as high-voltage cut-off, ventilation activation)?
Triggers VMS (vehicle management controller) through high-priority CAN messages forwarded by BMS, achieving hierarchical response: level-1 warning triggers cabin voice + forced ventilation, level-2 directly cuts main contactor + activates fire protection system.
8. How to reduce sensor drift and maintenance costs during long-term operation?
Built-in ABC automatic baseline correction + remote zero-point tracking function, cloud platform can monitor drift trends in real time, one field span calibration per year is sufficient. Typical lifespan >8 years, single-point maintenance cost controlled within 0.5% of the entire pack cost.
