What happens if the battery of an electric car breaks, and how is it repaired? In Volkswagen training centres, technicians learn to repair damaged battery packs.
Many people think that when an electric car’s battery reaches the end of its life cycle or has a problem, it is destined to end up in the garbage. Nothing could be more wrong: it would not only be uneconomic, but also a waste of precious resources. There are various ways to keep batteries in good working order during use, and it is also possible to repair them following a crash.
In Volkswagen training centres, employees of the brand’s service partners learn to repair battery packs. If damaged, the modular structure of the battery packs allows partial repairs, as well as accurate diagnostics, which is a more economical option, compared to replacing the whole battery.
Training and support
Volkswagen has two Qualification Centres in Germany, in Erfurt and Wolfsburg, soon to be joined by a third location, in Nürtingen. Here, employees from authorised workshops are taught how to deal properly with high-voltage batteries. Every service partner is qualified to maintain and repair batteries, and specific support centres, which specialise in battery repair, have also been created.
When a service partner accepts a Volkswagen electric vehicle, which they suspect may have a battery fault, they first perform a routine diagnosis: this is a procedure which allows them to determine the State of Health of the battery, that is its remaining capacity. This means, in other words, how much of the original storage capacity a battery can still provide, having been used for a number of years – a value which depends largely on how the battery is maintained.
In general, batteries feel most comfortable with a charge level of between 30 and 70%. Keeping the battery in this range reduces wear. For this reason, Volkswagen electric vehicles come with software that can be used to limit the maximum charge of the battery.
The first checks
If the initial examination points to a problem with the battery, the service partner hands the vehicle over to a support centre. Here the specialists check where the malfunction lies, for example in a control unit or in a battery cell. In the case of a car that has been involved in a crash, the battery casing is also checked.
If any potential risk is discovered, the car is first moved to a so-called quarantine area, where it is isolated and monitored. The repairs required depend on the results of the examination: if a deformation does not affect any sensitive parts, a dent does not necessarily mean there is a technical issue. The batteries in the ID. family also have a sandwich design, where the underbody protection and cooling system protect the battery cells from below.
The failure of individual cells within a battery module can easily be diagnosed. If one cell fails, the capacity of the module still remains between 50 and 66%, due to the parallel wiring of the cells. In this case, the remaining functional cells in the module must “work” harder, which results in them reaching a higher temperature with lower voltage.
In any case, if a cell is faulty, the complete module is exchanged, because individual battery cells cannot be replaced. The battery packs of vehicles based on the MEB platform consist of between seven and twelve modules, depending on the size. In general, if a battery still has 70% or higher residual capacity, it is definitely worth exchanging one or two modules.
A second life
Repairing batteries extends their service life in the vehicle. After this, they are given a so-called second life in a different application, for example as a stationary or mobile energy store.
The batteries are basically designed for the entire life of a vehicle, with more than 95 % of the battery able to be recycled at the end of its lifecycle. Precisely for this purpose, Volkswagen has started up its own specific recycling facility in Salzgitter.
VGI | Responsible UO: VP | Creation date: article date | Class 9.1