Solving the Challenges of Leak Testing EV Batteries

The Electric Vehicle (EV) sector is a growing field. Specifications and needs are still emerging, making it complicated for manufacturers of components like EV batteries to develop processes and fix test limits that will lead to a stable and high-quality product.

Rigorous leak testing is also a major element in the production of EV batteries. Every battery component, such as modules, cells, packs, and coolant systems, should be leak-tight to prevent inconvenience for customers and even disastrous failure.

While testing, the components of the batteries are particularly sensitive to problems, like barometric pressure fluctuation and temperature change. It is also difficult to detect the smallest leaks in large-volume components, such as EV batteries utilized in commercial vehicles.

Leak testing instrumentation needs the precision, traceability, and sensitivity required to meet the latest but crucial needs of EV battery testing.

Standard Leak Test Instrumentation for EV Battery Components

Cincinnati Test Systems (CTS) has more than 35 years of experience in offering leak test solutions for the most challenging applications. At present, the company is leveraging that experience into consulting with manufacturers involved in the EV market (modules, cells, packs, and cooling systems) and providing leak test instruments and services that help them understand, specify, and fulfill their needs.

CTS has already been working with some of the leading automotive and EV manufacturers and suppliers on testing solutions for their production lines.

Sentinel 3520

Sentinel 3520. Image Credit: Cincinnati Test Systems.

Sentinel I28

Sentinel I28. Image Credit: Cincinnati Test Systems.

CTS Sentinel 3520 — A Proven Leak Tester for EV Batteries

The CTS Sentinel 3520 instrument has been designed with the required strength, accuracy, and features to deal with a variety of battery applications, where things such as large volume and ballooning tend to become problems.

The 3520 provides pressure control and measurement sensitivity needed to fit the leak rates that are being managed by battery manufacturers as they narrow in on the exact specifications for this latest application.

CTS Sentinel 3520 — A Proven Leak Tester for EV Batteries

Image Credit: Cincinnati Test Systems. Click here to view the full infographic

Sentinel I28 — The Right Choice for Battery Cooling Circuits

The Sentinel 128 instrument can support differential pressure decay leak testing, which is perfectly suited for low-volume and low-leak rate parts, including cooling plates.

For a complete cooling circuit, the Sentinel 128 instrument offers an economical, easy-to-use solution with excellent performance to effectively perform the leak test.

Considerations for Leak Testing Battery Components


  • Guaranteeing the integrity of the cells for the product’s life


  • Establishing the leak rate of the module cooling circuit
  • No evident industry standard across manufacturers

Cooling Circuits:

  • Tubes, testing plates, and comprehensive cooling circuit with differing leak rates
  • Testing the validity of circuit connections

Battery Packs:

  • Air leak testing techniques are preferred, but tracer gas supplies repeatable sensitivity
  • Ip67 standards are normal, and IP69K in aggressive environments
  • No evident industry standard across manufacturers

Additional Issues with Leak Testing EV Battery Packs

In comparison to all the battery components, battery packs pose the most difficulties to leak testing. The size of a component is a problem as it is highly complicated to reliably test large volumes. Packs are prone to part expansion at unpredictable rates.

Moreover, atmospheric pressure and temperature affect the pressure in the parts, and when pressure fluctuations occur as a result of heating from an early process or atmospheric variations, test findings can be affected.

The aim with all battery testing, such as packs, is maximized cycle time, cost-effectiveness, and a repeatable, reliable test with low gage R&R.

CTS provides services and solutions to its customers’ requirements to resolve their leak test issues and fulfill these goals.

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