In the R&D and testing of modern packaged energy storage devices (such as power units in portable equipment and power modules), one critical experiment is the burst test. Its purpose is to simulate the process where, due to abnormal chemical reactions inside the device, a large amount of gas is generated rapidly, causing the housing pressure to surge and burst within tens of milliseconds. This allows engineers to capture key data: the peak pressure at the moment of rupture, the pressure rise rate, and the rupture initiation location. These data directly determine the safety design margin of the housing and the effectiveness of its pressure relief structure.
However, directly measuring pressure during the burst process presents three engineering challenges:
Random rupture location – Rupture tends to occur at the weakest point of the housing; a single‑point measurement may miss the true peak pressure.
Sensor survivability – The sensor must withstand the ultra‑high pressure shock of the burst without being damaged; otherwise, data will be lost.
Controlled cost – Since a single burst may destroy the measurement setup, the cost of the sensor must be manageable.
These challenges collectively point to the need for a pressure sensor that is small, high‑pressure resistant, suitable for multi‑point deployment, and moderately priced. The following sections detail its specific role in burst testing.
Measurement Principle: From Pressure to Electrical Signal
Such sensors typically employ a piezoresistive principle. The core sensing element is a Wheatstone bridge fabricated on a metal diaphragm or silicon wafer. When gas pressure acts on the sensor's pressure‑sensing diaphragm, the diaphragm undergoes elastic deformation on the micron scale, causing a change in the bridge resistance. This change generates a millivolt‑level voltage signal proportional to the pressure. An external data acquisition system then converts this signal into pressure values.
Chip pressure measurement principle
During the burst test, the internal gas generation rate is extremely high. Pressure often jumps from a normal value to a peak within tens of milliseconds, and may briefly exceed the sensor's range. Therefore, besides having sufficient response speed (millisecond level), the sensor must withstand short‑term overload without damage – which is the key reason for designing it to tolerate dozens of megapascals.
Array Deployment to Capture Rupture Initiation
Burst of a single housing usually starts at a localized weak point (e.g., weld seam, corner, or thinnest wall section). To capture the rupture initiation location and analyze pressure distribution, an array deployment scheme is often used: several sensors are installed at different positions on the same stainless steel chamber (which simulates the actual housing or serves as a fixture), and all sensors simultaneously record pressure‑time curves. By comparing the timing and amplitude of the peak pressure across channels, the rupture initiation point can be accurately identified, and the propagation path of the gas shock wave can be inferred.
Schematic of array deployment
Mechanical Interface and Installation Adaptability
The connection between the sensor and the stainless steel chamber relies on standard mechanical threaded interfaces (e.g., M20×1.5, G1/4, NPT), using face seals or tapered thread seals to ensure no leakage under pressures of dozens of megapascals. If the test fixture has non‑standard threads or limited space, the interface dimensions can be customized – including thread type, sealing surface diameter, thread length, and even the sensor's external contour – without modifying the existing fixture.
Engineering Considerations: Size and Cost
In burst testing, there is a certain probability that the sensor will be damaged along with the test piece (due to plastic deformation or rupture of the sensing diaphragm caused by overpressure). Therefore, the sensor needs to be compact (diameter approx. 10–20 mm, length 30–60 mm) so that it can be placed near housing weld seams or in narrow gaps. Meanwhile, the cost per unit should be lower than conventional pressure sensors on the market, making large‑scale multi‑point deployment economically feasible.
Conclusion
The core role of pressure sensors in burst testing is to reliably convert the transient high‑pressure gas changes inside an energy storage unit into recordable electrical signals, thereby quantifying the burst pressure, locating the rupture origin, and evaluating the pressure rise rate. Without such sensors, engineers would have to estimate peak pressure indirectly from housing fragment morphology or residual gas volume after burst, introducing large errors. Through array deployment, interface customization, compact size, and moderate cost, these sensors enable simultaneous pressure acquisition (at dozens of megapascals) from multiple weak points on a stainless steel chamber, providing direct, quantitative data for structural safety design and failure warning of packaged housings.
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