The Renault Zoe city car has been one of the most popular electric cars in Europe for years. According to Renault, the electric car batteries have proven themselves in simple endurance tests: more than 99 % of all batteries used in the Renault ZOE since the market launch in 2013 are still fully functional and have at least 70 percent of the capacity. This applies to all battery types - from the 22 kWh battery pack in the first years of production to the current 52 kWh battery.
There used to be a concern that the traction batteries in electric cars would lose a lot of power at an early stage or even break down completely. This has not yet happened on a large scale, but some remain concerned about long-term durability. Renault, therefore, grants a guarantee of eight years or 160,000 kilometers on purchased batteries from the ZOE - there used to be a rental offer. In addition, the French manufacturer guaranteed a minimum capacity of 70 percent of the value when the electric vehicle was purchased over this period or the entire distance.
Battery chemistry loses storage capacity over time. But, according to the company, this has only rarely happened beyond the framework guaranteed by Renault. "Less than one percent of all Renault ZOE batteries ever put into circulation fell below this mark and had to be replaced," says Renault. This also applies to vehicles whose battery guarantee has already expired. So concerns about declining power storage performance are unfounded, assures the carmaker.
The French company uses only lithium-ion batteries with a high energy and power density in the current Renault ZOE. Intelligent battery management measures the temperature and voltage of each battery cell in the "ultramodern" power storage devices. It thus ensures that they neither overheat nor get too cold during operation and therefore lose their performance. This protects the cell chemistry and thus provides a long and complication-free battery life.
In the event of a battery defect, Renault distinguishes whether the battery pack was purchased with the vehicle or rented separately. The latter was an offer available until November 2020, where the rental price was based on the term and mileage. In the case of a rental battery, the customer receives a used "but fully functional" battery whose condition meets the warranty conditions.
If this is worthwhile, the old electricity storage is repaired and put back into circulation, either as storage for an electric vehicle or stationary applications. It is different with purchased batteries: Here, Renault always sends the car battery for repair and then has it reinstalled in the car. The battery is only replaced if the repair costs exceed the battery value.
According to Renault, batteries can often be restored to an unrestrictedly suitable condition for everyday use by replacing individual modules. This is much cheaper than changing the entire battery pack and is particularly important for customers whose electric vehicles have already exceeded the battery warranty period. Only new modules are used for this. The battery of the current Renault ZOE consists of twelve such units, each containing 16 unit cells and housed in the same housing.
Renault workshops can determine the condition of the traction batteries using a diagnostic tool. In the future, this should also be possible for e-vehicle owners themselves via the My Renault app.
In addition, a digital battery certificate for the electric cars from Renault and Dacia about the remaining energy capacity of the drive battery is currently being developed. This digital battery certificate for electric vehicles should make it easier to calculate the residual value of the cars, contribute to easier resale and give the buyer certainty about the SoH (state of health) of their battery. The data for the digital battery certificate is read from the vehicle's battery management system. The information about the relationship between the original and the battery's current capacity is given as a percentage.
