Testing and type approval are central building blocks of automotive component and vehicle development.
In many cases, independent testing laboratories support their customers through the entire development process until commercialization of the vehicles.
For batteries and electric vehicles, testing is essential in the development process, as functionality and safety of the components and the entire vehicle can be evaluated by internal processes and verified by third parties.
The EU prescribes a series of mandatory tests for type approval.
- Mechanical tests ensure the stability of the battery housing for prevention of dangerous deformation or damage of the battery.
- Electrical tests prove the technical protection of cells and systems, for example, making sure battery management system is not at risk of causing overcharge or over-discharge.
- Thermal tests show the suitable design of the thermal management and ensure the stability of the cells at low and elevated temperatures.
- Electromagnetic compatibility tests ensure that the battery does not interfere with other surrounding systems and eventually cause a malfunction through electromagnetic radiation.
For type approval, each battery has to fulfill precisely defined test procedures within the aforementioned test categories. This test catalog represents the least minimum amount of testing that is required to prove technical and environmental safety of the system.
However, along with the increasing performance and safety requirements of the automotive industry, the demand for testing also increases.
Usually, upfront quality assurance is economically more advantageous than a root cause analysis on malfunctions in the field. Such analyses often include detailed examination of incidents, which are difficult to reconstruct. Moreover, in severe cases, for example a battery fire, most of the evidence is destroyed and conclusive evaluation is impossible.
Battery development is an iterative process, following project phases and distinct milestones from functional sample, to prototype and series production.
In each step and along the development life cycle of the system mandatory verification tests are integrated and augmented by additional tests to prove performance, functionality and safety under extreme conditions.
The test results in the early stage provide important information that can be directly incorporated into the development process.
During the type approval, the mandatory test procedure is applied to test objects already being manufactured using a series production process. For this purpose, production processes are defined, and product-specific, expensive tools are manufactured to map the defined dimensions of the system and ensure estimated tolerances.
A comprehensive, state-of-the-art testing procedure within the battery development is therefore of exceptional importance for manufacturers to avoid costly recalls and continuously improve the product.
Despite extensive testing before type approval, malfunctions or potential sources of danger sometimes force manufacturers to issue recalls. Among other root causes, impurities in the battery materials, immature production processes and malfunctions of electronic components can lead to overheating of the battery and eventually to reduction of battery quality.
In the worst case, this can also result in material harm or personal injury. The consequences for the manufacturer of the affected product can, in addition to the loss of credibility, range from considerable financial impact to insolvency of the company.
While severe battery disasters in the field are extremely rare, these events have to be eliminated under any circumstances. Therefore, it is very importance to simulate extreme situations to verify the safety of the battery during operation.
In addition to the aforementioned procedures, functional and misuse tests are extremely relevant. These include a variety of extreme conditions such as temperature shock, electrical shortcut, mechanical deformation and fire.
The demand for misuse tests is rising rapidly. However, the performance of misuse tests requires specialized testing facilities, equipment and expertise. That is why it has become a major bottleneck in the EV development process.
In summary, testing of the vehicle, components and battery is an essential part of vehicle development to confirm technical and functional safety of the overall system.
The verification of the product along the various sample phases requires know-how, investment and effort.
However, it is an important prerequisite for continuous product improvement, quality assurance and safe operation of the vehicle in the field. Although costly recalls cannot be entirely prevented by rigorous testing, it can definitely help to reduce the odds of occurrence.