The Importance of Battery Testing

Many different battery technologies are available on the market today, and each one has its own set of distinguishing characteristics. But even batteries with the same basic chemistry can exhibit substantial differences, especially when they come from different manufacturers.

Why is this? As you can imagine, each of the applications mentioned above have specific requirements with respect to the kinds of batteries needed to power them. Some need to last for only a couple of years, while others need to last 15 or more. Some of them require high power capabilities for charging and/or discharging, while others are more demanding when it comes to the energy content that can be contained and provided. Some systems consistently operate in a well-controlled and stable environment, while others need to be able to survive in harsh conditions. From this it’s clear that manufacturers of end applications need to select the most appropriate battery technology for their specific product. You might think that’s an easy job.

Well, think again. Manufacturers are liable for their end products. They have to comply with several standards, and they compete in the market to make the best offer in terms of both performance and cost. They need to make a well thought out decision on every aspect of the device, and so it's not surprising that they want to base their choice on the best information available.

For battery cells, modules or packs, information often comes in the form of a battery data sheet provided by the battery manufacturer. Strikingly, there is no real standard for such data sheets. The data you find on one sheet might be missing on another. Or maybe the characteristics are not defined in the same way. This makes it very difficult to compare one solution to the next. Moreover, most of the time, data sheet values are measured in conditions that are not representative for the end application. For these reasons, it’s almost impossible for product manufacturers to estimate the real value of a battery.

To assess the ‘value’ of a battery in an objective way, it should be subjected to more elaborative testing. To obtain the most reliable results, testing activities should be carried out at dedicated battery testing laboratories. These facilities are often equipped with multiple testing devices specifically designed for testing battery cells, modules and complete packs or even systems. Testing can include electrical, mechanical and/or thermal test programs.

Testing equipment can run standard testing protocols, as defined by the international community, but can also be programmed to perform specific testing that is more relevant to the end application.

Testing equipment can run standard testing protocols, as defined by the international community, but can also be programmed to perform specific testing that is more relevant to the end application.

Examples of measurements related to the performance, ageing and safety of batteries include:

• Capacity at different charging and discharging rates in different thermal conditions
• Internal resistance or impedance at different life stages
• Calendar and cycle life in different (operational) conditions
• Robustness of the battery
• Heat generation during charging and discharging processes

VITO/EnergyVille has vast experience and expertise in setting up and executing testing programs for

different battery technologies aiming to feed different end applications. In an information sharing

and practical training session people will get more familiar with some specific testing procedures.

Why are the tests being performed? What is the correct approach for testing cells, modules and

packs? Which equipment is to be used? How to process the testing data to obtain results for end

customers, battery modelling purposes or the development of battery management systems (BMS)?

Whether you are working in a relevant field or you are just a battery enthusiast, it’s likely you have a lot of questions about battery testing. What is the correct approach for testing cells, modules and packs? Which equipment should be used? How do you process testing data to obtain results for end customers? Or how do you process data for battery modelling or the development of battery management systems (BMS)? Why are these tests being performed?

If you’re working in a position or field where these questions are relevant, it’s important you take steps to form a deeper understanding of battery testing—and not just through information sharing. In order to grow more familiar and confident about specific testing procedures, we recommend completing practical courses and training.

Jeroen Büscher

VITO/EnergyVille