Power battery thermal runaway gas collection tester: technical architecture and safety test system innovation
Publish Time: 2025-05-19
With the global electric vehicle ownership exceeding 40 million, safety accidents caused by thermal runaway of power batteries have become the core pain point restricting the development of the industry. The flammable gases (such as hydrogen, carbon monoxide, and alkane compounds) released during thermal runaway not only threaten personnel safety, but may also cause secondary explosions. In order to solve this problem, a power battery thermal runaway gas collection tester integrating pressure-bearing and sealed design, multi-modal triggering test and gas composition analysis came into being. This article analyzes the innovative value of the device from four dimensions: technical principles, functional modules, safety design and test process.
1. Technical architecture: pressure-bearing and sealed and multi-modal triggering test
Pressure-bearing and sealed container design
Material and structure: The main body adopts a 316L stainless steel double-layer jacket structure, the inner layer bears a pressure of ≥5MPa, and the outer layer maintains the container temperature ≤80℃ through a circulating water cooling system to avoid high temperature damage to the sensor.
Safety redundancy: Equipped with a dual pressure relief mechanism of bursting disc (burst pressure 6MPa) and electromagnetic pressure relief valve (pressure threshold 5.5MPa) to ensure that the container does not physically rupture under extreme working conditions. Multimodal trigger test system
Overcharge trigger: A programmable DC power supply is used to achieve 0.1C~5C rate controllable charging, supporting constant current-constant voltage (CC-CV) and constant power (CP) modes, simulating user misoperation or charging pile failure scenarios.
Heating trigger: The battery surface is wrapped with a flexible silicone heating film, the heating rate is adjustable (1~10℃/min), the temperature control accuracy is ±0.5℃, covering the 55℃~130℃ test range required by GB 38031-2020 standard.
Needle trigger: Equipped with a tungsten steel needle (diameter 3mm) driven by a high-speed servo motor, the puncture speed can reach 100mm/s, and it supports multi-angle puncture (0°/45°/90°) to simulate the internal short circuit or mechanical damage of the battery.
2. Functional modules: multi-source data acquisition and gas composition analysis
Multi-parameter real-time monitoring
Temperature field reconstruction: deploy 16 K-type thermocouples to form a three-dimensional temperature field distribution map with a spatial resolution of 5mm to capture local hot spots (such as pole ears and explosion-proof valve areas) during thermal runaway.
Voltage/current monitoring: Hall sensors and isolated sampling circuits are used to achieve millisecond-level synchronous acquisition of voltage (0~1000V) and current (0~1000A), with a data refresh rate of ≥1kHz
Video image recording: Through explosion-proof high-speed cameras (frame rate ≥1000fps) and infrared thermal imagers (resolution 640×512), battery surface deformation, electrolyte splashing and gas release processes are recorded.
Online analysis of gas composition
Sampling system: A micro vacuum pump and solenoid valve array are used to achieve gas sealing capture within 0.1s after thermal runaway to avoid mixing with air.
Detection technology: Integrated gas chromatography-mass spectrometry (GC-MS) and electrochemical sensor array, which can quantitatively analyze 12 key gases such as hydrogen (H₂), carbon monoxide (CO), and methane (CH₄), with a detection limit of ppm.
Data analysis: Based on machine learning algorithms, a correlation model between gas composition and thermal runaway stages (gas production, eruption, combustion) is established to predict the severity of thermal runaway.
3. Safety design: multiple protection and emergency response
Active protection mechanism
Inert gas protection: Nitrogen (purity ≥ 99.999%) is automatically filled before testing to reduce the oxygen concentration in the container to below 3% to inhibit the combustion reaction.
Cooling water circulation: Built-in spiral coil and external cooling tower, the container temperature is reduced to below 40°C within 10 minutes after thermal runaway, which is convenient for subsequent disassembly and analysis.
Emergency response system
Flame detection: Using ultraviolet-infrared composite flame sensor, the response time is ≤50ms, and the heptafluoropropane fire extinguishing device is automatically started after triggering.
Data backtracking: The black box module (powered by an independent power supply) can store data for 72 hours before the test and support accident cause tracing.
4. Test process: standardized operation and typical cases
Standardized test process
Pretreatment: After the battery is fully charged, it is left to stand for 24 hours to ensure the consistency of SOC (state of charge).
Trigger test: Select a single or combined trigger mode (such as "overcharge + heating" composite working condition) according to the needs.
Data acquisition: Synchronously record temperature, voltage, gas composition and video images, with a sampling interval of ≤100ms.
Post-processing: Microscopic characterization of the wreckage through thermogravimetric analysis (TGA) and scanning electron microscopy (SEM).
Typical application cases
Case 1: Overcharge test of high-nickel ternary battery
Under 5C overcharge conditions, the battery triggered thermal runaway at 8 minutes and 12 seconds, CO₂ accounted for 68% of the released gas, and the peak H₂ concentration was 12000ppm. The video shows that the explosion-proof valve was opened at 900℃. Case 2: Needle Puncture Test of Lithium Iron Phosphate Battery
After puncturing at a 90° angle, the battery did not produce an open flame, but the CO concentration in the released gas reached 4500ppm, indicating that the internal electrolyte decomposed violently, verifying the safety advantage of lithium iron phosphate materials.
5. Technical Value and Industry Impact
R&D End: Shorten the battery safety performance verification cycle. For example, a company compressed the thermal runaway test time from 72 hours to 8 hours through this device, reducing the R&D cost by 60%.
Regulatory End: Provide quantitative testing methods for standards such as GB 38031-2020. For example, a certain model was recalled due to excessive gas release to avoid potential accidents.
Recycling End: Judge the health status of retired batteries through gas composition analysis. For example, the hydrogen release of batteries with electrolyte leakage is more than 5 times that of normal batteries.
The power battery thermal runaway gas collection tester provides the industry with a technical path from "passive protection" to "active warning" through the integrated innovation of pressure-bearing closed design, multi-modal trigger test and gas composition analysis. In the future, with the emergence of new technologies such as hydrogen energy storage and solid-state batteries, the device will need to further expand its detection capabilities for special gases such as high-pressure hydrogen and metallic lithium vapor, to help ensure the safe implementation of global energy transformation.
