One of the many myths to debunk about electric cars is the following: if the battery is damaged, it has to be replaced. Or rather, the statement is true, but only in part. That is, only in cases where the damage affects a large portion of the battery pack, or where its remaining capacity has been drastically reduced. In all other scenarios, repairing and restoring a battery is not only possible but a duty, since it avoids wasting large quantities of valuable raw materials, as well as offering a financial saving.

Electric cars: batteries require new skills

As is easy to imagine, since these are high-capacity battery packs operating at high voltage, a high level of technical specialisation is essential for any work carried out on them. For this reason, Volkswagen has two dedicated training centres (in Erfurt and Wolfsburg) and will soon open another in Nürtingen, also in Germany. Here, staff from authorised workshops learn all the ins and outs of the (new, at least in part) trade.

What happens when a battery fails

Given the high level of specialisation required, not all authorised Volkswagen workshops are able to repair batteries. The current situation is as follows: on one hand, every service partner of the brand is qualified for battery maintenance and replacement. On the other, repair work is carried out only at specific, highly specialised assistance centres. In more practical terms, when an authorised workshop takes in a Volkswagen electric vehicle with a possible battery fault, it immediately carries out a routine diagnostic check. This analysis makes it possible to determine the battery's remaining capacity and what percentage of its original storage capacity can still be used — a value that depends above all on how the battery has been maintained.

Batteries go into quarantine too

If the initial examination does reveal a problem, the vehicle is taken in by a specialised assistance centre. Here, specialists identify the cause of the malfunction (for example in the control unit or in a cell) and, if the car has been involved in an accident, the battery casing is also inspected. Where a potential risk exists, the car is isolated and monitored in what is known as the quarantine zone. Subsequently, based on the results of the examination, the necessary repairs are carried out. If the deformations do not affect sensitive areas, a dent does not necessarily correspond to a technical problem. The batteries of the Volkswagen ID. electric range, for example, have a "sandwich" structure, with an underbody guard and a cooling system that protect the cells from below.

What happens when the cells fail

We have seen that a battery fault does not necessarily mean the battery has to be replaced. Take the case of a problem with a cell: the module in which it is housed continues to work, albeit at reduced capacity — that is, between 50 and 66 per cent. In this case, the functioning cells work harder, which is why they reach a higher temperature at a lower voltage. In any case, if a cell is faulty, the entire module is replaced, because the individual cell cannot be replaced on its own. Replacing a module, however, is a very different matter from fitting a new battery pack: on vehicles based on the MEB platform (the Volkswagen Group's modular platform dedicated to electric vehicles), the battery pack is made up of a minimum of seven and a maximum of twelve modules, depending on the size. In general, if a battery still has at least 70 per cent of its remaining capacity, replacing one or two modules is certainly cost-effective.

The second life of batteries

Before looking at what happens to battery packs that can no longer be used in a car, it is worth recalling the first and most important rule for ensuring a long service life. In general, battery packs perform at their best when the charge level is between 30 and 70 per cent. Keeping the battery within this charging range reduces wear. This is why Volkswagen electric vehicles are equipped with a software function that allows a limit to be set for the charging level. Batteries are designed to last as long as the vehicle; at the end of their useful life in the car, they can begin a second life — for example as a stationary or mobile energy storage unit. After that, it is possible to achieve a recycling rate of 95 per cent. With precisely this in mind, Volkswagen has activated its own dedicated recycling facility in Salzgitter.