Before a battery pack finds its place in an electric vehicle, it must prove its integrity across multiple dimensions—safety, performance, durability, quality, and compliance. Given the high energy density of EV batteries, any flaw—be it a short circuit, faulty cell, or insulation failure—can escalate into thermal runaway, fire, or worse. This makes pre-assembly testing not just important, but indispensable.
To address this, AVL List GmbH, the Graz-based leader in mobility testing and simulation, has introduced the Battery Cycle Tester—a bi-directional, multi-channel DC power supply designed to test and validate batteries at cell, module, and pack levels.
“Understanding a battery’s behaviour before building it into a pack is crucial,” explained Christian Miesner, Vice President – Battery & Cell Testing at AVL Deutschland GmbH. Speaking to Mobility Outlook, he said AVL’s Battery Cycle Tester allows battery makers and even vehicle manufacturers to test for cycle life, charging speed, performance consistency, and supplier reliability.
For instance, a cell in automotive use must typically endure at least 1,000 cycles before capacity dips to 80%. Testing confirms whether it meets this threshold—and more importantly, whether every cell in a batch performs uniformly. It’s only with this foundational understanding that packs can be safely constructed. Even after cells are integrated with cooling systems and housings, further testing is essential to confirm that pack performance matches theoretical expectations. AVL's tools provide the insight necessary to monitor and validate these dynamics—ensuring each battery component functions not just individually, but cohesively across the entire system, he said.
From Cell To System
AVL’s strength lies not only in advanced battery testing technology but in supporting customers across the entire battery value chain—from sourcing and verifying cell quality to assembling, testing, and validating the complete battery pack. One of its largest clients, “Volkswagen’s PowerCo gigafactory, exemplifies how leading OEMs rely on AVL to equip large-scale battery production and testing ecosystems,” he said.
As Miesner explained, AVL covers a broad spectrum of testing disciplines. Its systems enable both electrical performance testing—such as fast-charging capabilities and life cycle validation—and safety and environmental compliance tests, including nail penetration, drop, crush, and submersion tests, as required by global homologation standards.
Beyond individual machines, the testing equipment maker also builds complete battery test labs. While acquiring test units or chambers is straightforward, running an efficient lab at scale is not. Efficiency hinges on automated data analytics, intelligent scheduling, and streamlined channel repopulation. AVL’s lab management solutions, integrated with advanced software, flag anomalies automatically, prioritise test data, and optimise throughput—crucial for customers developing production-ready battery systems under tight timelines, he explained.
Whether a company is an OEM building its own packs, a cell manufacturer, or a third-party assembler supplying batteries to automakers, AVL provides the tools to test at cell, module, and pack levels. Clients like Mahindra already leverage AVL's capabilities to meet the complex demands of EV battery development, he pointed out.
Turnkey Labs, Scalable Solutions
For vehicle manufacturers, partnering with AVL offers a distinct edge: turnkey test labs with guaranteed timelines and performance, supported by the broadest portfolio in the industry. Whether it’s for cost-conscious operations or high-performance development, the company delivers scalable, precision-driven solutions tailored to specific needs, he said.
At the cell testing level, Miesner said, the company offers two product lines. The Eco Line—a rugged, air-cooled system built for price-sensitive customers—delivers strong accuracy and automation with reliable dynamics. Meanwhile, the Performance Line is water-cooled, energy efficient, and integrates advanced features like impedance spectroscopy, ideal for premium manufacturers needing fast cell aging tests, low energy consumption, and sustainability without compromising performance.
The same flexibility extends to pack testing systems, with value-oriented air-cooled setups and high-efficiency water-cooled solutions for performance-driven labs. The unified automation platform across both lines ensures consistency and operational ease, he mentioned.
As for integrating battery testing within vehicle assembly lines, he noted that end-of-line battery tests are relatively fast—typically under 30 seconds—involving basic energy acceptance and safety checks like high-potential testing. “These are carried out post-battery production but prior to vehicle integration, meaning they don’t bottleneck final assembly,” he clarified.
However, quality assurance doesn’t end there. In high-volume production—such as 100,000-unit runs—periodic offline testing is essential. Manufacturers must frequently sample and rigorously validate batteries to detect any deviations in performance or thermal behaviour. Even elements like glue, used not just for adhesion but for thermal dissipation, must be monitored closely to ensure consistent quality and safety across every unit delivered, he observed.
Accelerating Validation
While end-of-line battery tests typically take only a few minutes, the full validation cycle for a newly developed battery—cell or pack—can stretch across six to twelve months, primarily due to exhaustive life cycle testing. But in a fast-moving automotive landscape, where time to market is critical, AVL offers a smarter, faster alternative.
“This is where AVL’s Performance Line stands out. Unlike conventional testers, it integrates impedance spectroscopy—a powerful tool that enables predictive diagnostics of battery health. Rather than running thousands of charge-discharge cycles blindly, engineers can perform short bursts—say, 30 cycles—followed by impedance scans to assess the cell’s current state,” he mentioned.
These readings feed into a simulation model that, over time, learns from the battery’s behaviour and accurately predicts its cycle life. This hybrid approach of real-time testing with virtual modelling can cut validation time by 20–40%, potentially saving two to three months from a typical nine-to-twelve-month cycle, he revealed.
For automakers, this reduction translates directly into faster product launches and competitive advantage. With AVL’s advanced battery intelligence, “manufacturers no longer just test—they accelerate,” he added.
Prognostics & Predictive Insights
According to Meisner, battery health doesn’t decline overnight—it’s a gradual process that, when tracked effectively, can unlock deeper value for both OEMs and users. Today, most Battery Management Systems (BMS) already monitor state of health in real time. While a battery is deemed 'dead' when capacity drops below 80%, this is more a functional threshold than a hard stop. Just like a phone with 70% battery life may still operate efficiently—albeit with more frequent charging—EVs can still be used safely with reduced range.
Miesner confirmed that prognostic systems are entirely feasible. When the BMS is connected to the OEM’s data system, manufacturers can predict degradation trends, advise users on battery replacement, or even suggest new vehicle upgrades based on usage patterns. Brands like Tesla are already leveraging this connectivity to enable predictive maintenance and manage risk, he said.
While rare, battery fires are a concern—but well-designed packs today allow for a 30-minute no-flame window, providing ample time for evacuation. The future aim is to fully contain thermal events within the pack, minimising external harm. However, “proactive safety is more about preventing degradation than reacting to failure,” he said.
Ageing Gracefully, Charging Wisely
Battery ageing is shaped by charging habits and driving style. Frequent high-speed fast charging accelerates wear, whereas moderate home charging significantly extends life. “Manufacturers could, in the future, offer usage-based recommendations—encouraging gentler acceleration and balanced charging routines,” he opined.
With a well-calibrated BMS, batteries can even self-regulate and recover some performance loss. Proven by high-mileage EVs—like early Teslas with over 500,000 km logged—longevity is achievable. When paired with predictive diagnostics and smart usage, electric vehicles can deliver sustainability not just in propulsion, but in lifespan.
Miesner wrapped up the conversation by stating that AVL’s comprehensive approach ensures that manufacturers not only accelerate EV production, but do so with uncompromised quality, traceability, and efficiency.
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