Aging Test For Batteries

Aging Test For Batteries

Before shipping, we need do the test for every battery.Regardless of condition, all items must be packaged appropriately so as not to incur physical damage during return shipping.

Every year, with the development of product designs,  lithium-ion batteries  become smaller and more powerful. These new batteries power medical devices, electric vehicles, consumer electronics, and grid storage devices and are often expected to last years, if not decades. Unfortunately, the design changes that result in these new batteries can have unintended effects on how they age over time.

It is particularly important to understand the changes of the batteries these years because they need to be sure that these new batteries will be applied to meet their specific and potentially unique use case. As an example of an unintended effect, raising voltage can improve performance in the short term, but it may cause the battery to age more rapidly in the long term. In the worse sense, it can potentially cause the battery to swell with gas or develop a short circuit. To understand these and similar tradeoffs, lithium-ion battery experts are required to do a lot of aging testing to ensure their perfomance. 

Accelerated aging is a tool that stresses the battery. It differs from stress testing in that it focuses on applying multiple levels of stress in an attempt to predict behavior. Arrhenius modeling is one such method that can predict (within limits) battery capacity, swelling caused by gas generation, and other behaviors across a multitude of temperatures. This test works by nothing than just sped up by increasing the temperature at which the reaction occurs. An easy way to visualize  how this is with a glow stick. Glow sticks create light via a chemical reaction that produces photons.

The higher the temperature is, the quicker the reaction is. As a result, a glow stick in cold water glow less brightly than a glow stick in hot water. Similar phenomena occur in batteries, except rather than creating light, they lead to undesirable chemical reactions that can decrease capacity, cause gas generation, or have other negative effects on performance. By carefully measuring how quickly these undesirable reactions occur at different temperatures, models can be made to predict the aging behavior.

These models can be used to predict and show how the batteries age over time, which can help inform warranty and supply chain storage decisions. Now, of course, these models may not work at all temperatures, or experience all reactions, but Exponent often finds that loss of capacity, loss of power, and gas generation are well predicted by using these techniques.

After several aging tests, we hopefully can provide our clients with better experience and intend to expand the life period of the batteries.