Automotive Battery Valves: The Core Control Unit for Safety and Performance of New Energy Vehicles

In today's era of rapid development in the new energy vehicle (NEV) industry, power batteries serve as the "energy heart" of the entire vehicle. Their safety and performance stability directly determine vehicle quality. As the core executive component of the Battery Management System (BMS), automotive battery valves establish a safety defense line and efficiency guarantee system for power batteries through precise fluid control and pressure regulation, becoming a key hub connecting battery performance optimization and safety protection.

1. Analysis of the Core Functions of Automotive Battery Valves


Automotive battery valves are precision components integrating pressure sensing, fluid control, and status feedback functions. Their core functions revolve around safety protection, performance regulation, and status management of the battery system, which can be specifically divided into three dimensions:

(1) Safety Protection: The "First Line of Defense" Against Thermal Runaway


During charging-discharging cycles, mechanical impacts, or short-circuit faults, power batteries are prone to thermal runaway accompanied by massive gas generation, leading to a sudden pressure surge inside the battery pack. Battery valves achieve active protection through a graded pressure response mechanism:

  • They maintain the battery pack in a sealed state under normal conditions.
  • When the internal pressure reaches a critical threshold (e.g., 3kPa), the pressure relief structure opens quickly to release pressure through a directional exhaust channel.

    Some high-end products, such as Eaton 3-in-1 battery exhaust valves, further integrate triple functions of passive pressure relief, active exhaust, and leak detection. After pressure release, they can be resealed via resealing technology to prevent moisture and dust intrusion. This "pressure relief first, then sealing" design effectively reduces the risk of battery pack explosion and buys precious time for occupant escape.

(2) Thermal Management Regulation: The "Precise Regulator" for Battery Efficiency


The optimal operating temperature range of power batteries is 25-40℃. Excessively high temperatures accelerate cell aging, while excessively low temperatures cause capacity degradation. By linking with the vehicle's thermal management system, battery valves achieve dynamic temperature balance:

  • When the battery temperature exceeds the set threshold, the BMS triggers the opening of the water circuit solenoid valve, introducing coolant cooled by the air conditioner into the battery liquid cooling circuit to quickly dissipate heat.
  • When the temperature drops below the critical value, the solenoid valve switches the circuit, guiding waste heat from components like the motor controller into the battery heating circuit to achieve efficient energy recovery.

    Some high-end solenoid valves adopt a spool-type structural design, with a response time controlled within 0.05 seconds, ensuring real-time and precise temperature regulation.

(3) Sealing and Pressure Balance: The "Guardian" of Battery Lifespan


Power battery packs need to meet a protection rating of IP67 or higher, while also addressing internal and external pressure differences caused by altitude changes and temperature fluctuations. Battery valves adopt a design that combines a polymer waterproof and breathable membrane with a precision valve body. While achieving dust and water resistance, they maintain pressure balance inside and outside the pack through a low-flow breathing mode. This balance mechanism not only prevents seal deformation and aging due to pressure differences but also avoids condensation formation, providing a stable operating environment for battery cells and significantly extending the battery's cycle life.

2. Typical Application Scenarios of Automotive Battery Valves


As power battery technology advances toward higher energy density and faster charging, the application scenarios of battery valves have expanded from basic safety protection to full-lifecycle management, focusing mainly on the following three areas:

(1) Power Battery Pack Safety System


Power battery packs of battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) are generally equipped with explosion-proof, waterproof, and breathable valves, usually installed in the pressure relief area at the rear of the battery pack. Taking products from Goel Technology (adopted by automakers such as Tesla and BYD) as an example:

  • Their combination of breathable membranes and mechanical pressure relief structures enables pressure balance under normal operating conditions.
  • They can open the pressure relief channel 100% during thermal runaway, and the valve body remains intact and reusable after pressure relief.

    For high-risk cells like lithium nickel cobalt manganese oxide (NCM) batteries, some vehicle models are also equipped with active electromagnetic exhaust valves, which can trigger exhaust in advance via the BMS to nip thermal runaway in the bud.

(2) Intelligent Thermal Management Circuit


In integrated thermal management systems, battery valves play a core role in circuit switching and flow regulation. According to the active thermal management solution of a certain NEV model:

  • The system uses 3/2-way solenoid valves to quickly switch between cooling and heating modes.
  • During cooling, it connects to the air conditioning cold water circuit; during heating, it switches to the motor waste heat recovery circuit.

    The on-off response of the solenoid valve directly determines the accuracy of temperature regulation. Such applications have extremely high requirements for valve sealing, with the leakage rate needing to be controlled within 10mL/min to avoid coolant loss affecting thermal management efficiency.

(3) Energy Storage Battery System Protection


In large-capacity battery packs of commercial vehicles and energy storage stations, battery valves achieve large-scale protection through cluster control:

  • When a cell produces abnormal gas, the regional pressure sensor triggers the corresponding solenoid valve to open for pressure relief.
  • At the same time, it feeds back the status to the central controller via the CAN bus, enabling accurate positioning and isolation of faulty cells.

    This distributed control mode not only ensures the safety of individual battery groups but also avoids overall system shutdown.

3. Key Selection Factors for Automotive Battery Valves


The selection of automotive battery valves must balance safety, adaptability, and durability. Combining the Technical Requirements for Solenoid Valves for Pneumatic Control of Motor Vehicles and actual application scenarios, the following parameters should be focused on:

  • Pressure Response Characteristics: Select the opening threshold based on the designed pressure of the battery pack. For NCM battery systems, products with customizable opening pressure are recommended, with a tolerance controlled within ±6%.
  • Environmental Adaptability: It should meet an operating temperature range of -40℃~85℃, a protection rating of no less than IP65, and the red rust corrosion area should be ≤15% after a 72-hour salt spray test.
  • Medium Compatibility: Components in contact with media such as coolant and battery electrolyte should use corrosion-resistant materials (e.g., aluminum alloy valve bodies with fluororubber seals).
  • Lifespan and Reliability: The mechanical lifespan should be ≥7.5 million cycles, and the electromagnetic coil temperature rise should be <100℃ to meet the vehicle's 8-year/150,000-kilometer warranty requirement.
  • Integration Requirement: For compact vehicle models, priority should be given to products with base-integrated valve groups to reduce installation space.

4. Recommended Product: Technical Adaptability of Airtac Solenoid Valves


In the practical application of automotive battery valves, Airtac (Yadeke) solenoid valves have become a preferred solution in the NEV field due to their precision manufacturing technology and scenario-based design. Their core advantages are reflected in three dimensions:

(1) Precise Matching of Performance Parameters


Airtac 4V Series and 5V Series solenoid valves adopt a spool-type structural design. The inner hole, processed by special technology, significantly reduces frictional resistance. With a starting air pressure as low as 0.15MPa, they are fully compatible with the low-pressure operating environment of battery thermal management systems.

  • The product’s operating temperature range covers -20~70℃, and its protection rating reaches IP65, enabling it to withstand high-temperature and vibration environments near the battery pack.
  • Its response time of less than 0.05 seconds allows it to quickly execute temperature regulation commands from the BMS, avoiding excessive battery temperature fluctuations.

(2) Outstanding Reliability and Durability


This series of solenoid valves undergoes 100% factory testing, with a leakage rate far lower than the industry standard of 10mL/min. They can operate stably for a long time without oil lubrication, reducing post-maintenance costs.

  • The aluminum alloy valve body and reinforced sealing structure design control the pressure change rate within ±5% in impact pressure resistance tests, meeting the strict durability requirements of power battery systems.
  • In addition, double-headed 2-position solenoid valves have a memory function, and 3-position products offer three function options (mid-position closed, exhaust, and pressure), which can adapt to different thermal management circuit designs.

(3) Convenient and Efficient Engineering Application


Airtac solenoid valves provide multiple connection port sizes (from PT1/8 to PT1/2) and voltage specifications (e.g., AC220V, DC24V), which can be directly connected to the BMS interfaces of mainstream automakers.

  • The product is equipped with a manual device for easy installation and commissioning.
  • The integrated valve group design can reduce installation space by more than 50%, making it particularly suitable for the compact layout requirements of NEV battery compartments.

Conclusion


The technological iteration of automotive battery valves has always resonated in the same frequency as the safety upgrades of power batteries. From a single pressure relief function to intelligent thermal management control, they have become an important part of the core technological competitiveness of NEVs. With its precise control performance, reliable protection capability, and flexible adaptability, Airtac solenoid valves perfectly meet the triple demands of automotive battery systems for safety, efficiency, and durability. They provide solid hardware support for the full-lifecycle management of power batteries and are an ideal choice for NEV battery valve selection.
Back to blog

Featured collection