AZL Aachen Commissions JetBlast Battery Casing Test System

AZL Aachen has commissioned a new test system designed to evaluate battery casing materials under extreme conditions. The system, named JetBlast, combines intense flame exposure with a blast of heated particles to replicate the stresses materials face during cell venting and thermal runaway events in electric vehicle batteries.

Initial calibration trials have established a benchmark operating point for the system. These trials are part of the "Thermal Runaway Testing for Battery Casings" Joint Partner Project, which AZL launched in 2025. The company states it will finalize repeatability and reproducibility checks before materials from project participants begin formal testing.

System Specifications and Calibration

The JetBlast system can generate extreme heat. AZL reports the maximum test-zone temperature is 1,650° Celsius, measured approximately 5 millimeters in front of the specimen surface. The current benchmark test profile uses a sequence of base and boost heating modes.

In boost mode, the target temperature at that near-surface position is 1,300° C before the particle blasting phase even begins. Initial calibration measurements showed the subsequent particle-laden blast reaches roughly 1,250° C close to the same plane. This creates a differential of about 50° C between the boost target and the blast condition. AZL notes this differential can be adjusted through the system's operating settings, and the stability and reproducibility of these conditions will be documented in a released calibration protocol.

A key technical challenge the system addresses is blast-induced cooling. Using cold carrier air to propel particles can cool a pre-heated specimen, distorting the intended combination of thermal and erosive loads. AZL says JetBlast is engineered to reduce this unwanted cooling effect.

Custom Engineering and Testing Context

AZL developed the system's core components in-house rather than adapting commercial parts. The company built its own burner and particle-injection architecture. This allows for coordinated control over flame temperature, particle temperature, particle mass flow, blast intensity, and exposure time within a single, configurable sequence.

JetBlast represents the third family of methods in AZL's fire-testing portfolio for battery enclosures. The first method assesses material strength during fire exposure while under a defined tensile load. The second comprises custom torch-and-grit and particle-blasting techniques developed for specific programs with OEMs and tier-one suppliers.

Outputs and Project Scope

The system is designed to provide detailed diagnostic data, not only a simple pass-or-fail result. Potential outputs include temperature development on both the exposed and back sides of a specimen, time to reach a specific threshold or burn-through, material integrity, damage area, mass loss, evidence of cracking or delamination, continued burning, and failure modes.

AZL is clear about the system's purpose. It describes JetBlast as a screening and development tool for selected thermal and particle-impact loads. The company states it does not replace full cell-, module-, pack-, or vehicle-level testing required under standards like GB 38031-2025 or UN Regulation No. 100. Also, it does not generate the pack overpressure that occurs in real thermal runaway events.

Ravi Chaitanya Bhairi, AZL's Head of Fire Testing for E-Mobility, explained the project's philosophy. "The objective is not to imitate one cell event once," he said. It is to identify the damage-driving loads, reproduce them in a controlled profile and use the evidence to match the material, protection concept and casing architecture.

The standard project offer includes testing of two participant-selected materials or material configurations per company. AZL reports that companies can join the joint partner project until September 2026.