Cells and modules of lithium-ion batteries are important because they are the basic building blocks of a lithium-ion battery. Cells are the individual components that make up a battery, and modules are groups of cells that are connected to form a larger battery. Cells and modules are important because they determine the size, capacity, and performance of the battery. They also determine the safety and reliability of the battery, as well as its cost.

Batteries aging and performance testing is important because it helps to ensure that batteries are performing at the optimal level of their lifetime and that they are safe to use. It also helps to identify any potential issues with the battery before they become a problem. This testing can help to extend the life of the battery and ensure that it is providing the best possible performance such as fast charge and discharge.

The EUCAR hazard levels define the outcome of cell-level safety testing. These levels are normally used to describe the outcome of tests such as overcharge as part of cell specification. EUCAR Hazard level is a system used by the European Commission to assess the risk of a particular chemical or substance.

It is based on the European Union Classification, Labelling, and Packaging (CLP) Regulation and is used to classify hazardous substances into four categories: acute toxicity, skin corrosion/irritation, serious eye damage/eye irritation, and specific target organ toxicity. The hazard level is determined by the type and amount of the substance, as well as the duration and frequency of exposure.

Aging tests: these involve testing at a certain temperature without the battery load cycle. They are performed within a safe temperature range for the battery.

 Performance tests: various battery-specific parameters, such as the load state, are tested with overlapping temperature ranges. These tests are performed within a safe temperature range for the battery.

Stress tests: various battery-specific parameters, such as the load state, are tested with overlapping temperature ranges. These tests are performed at the limit of the safe temperature range for the battery. This category also includes tests with higher charging and discharging currents overlapping with constant or dynamic temperatures.

Extensive performance tests are carried out to determine the performance of the cells and modules (safety package P). The components are therefore brought to the limits of their performance and load capacities by exposing them to constantly changing temperatures, with and without a current.

The test object is exposed, for example, to temperatures of -10 degrees Celsius to 55 degrees Celsius in the cooling incubator under continuous temperature changes. Test scenarios are also carried out in the environmental simulation chamber in climatic ranges of -30 degrees Celsius to 60 degrees Celsius at up to 96 percent RH. The duration of the tests varies. Some tests last several months with extreme demands on the material. Other tests require years with lower demands.