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Your regular update for technical and industry information
State of health | The flash test of TÜV SÜD and AVILOO supplies reliable results on the battery state in used electric vehicles within a few minutes. The cost-effective remarketing solution is interesting for car dealerships, car workshops and commercial customers.
TÜV SÜD already offers the SOH test for private customers as a premium test. A B2B product for commercial customers is now also available.
With the flash test, TÜV SÜD, together with the battery specialists AVILOO, offers a quick test for determining the state of health of the traction battery. The test also provides information about the history of the accumulator.
The traction battery in the electric car is the most expensive component and its state decides on the actual value when a used vehicle is sold. A reliable statement about the state of the battery – its State of Health (SOH) – is therefore very valuable, not only for sellers but also for buyers. Handling, charging cycles, age – these are factors that influence the state of batteries. Use leaves its mark, which can reduce the capacity of the battery.
Since April, in cooperation with the Austrian company AVILOO, TÜV SÜD has offered state of health battery tests in selected TÜV SÜD service centres. The premium test of the drive battery is tailored to end users and is very easy to carry out. The appointment for collecting the box from the service centre is made conveniently online.
“To perform the test, the AVILOO box is connected to the vehicle’s OBD interface. The device then collects raw data from the battery during normal daily operation of the vehicle”, is how Markus Gregor, Product Manager Battery Evaluation at TÜV SÜD, describes the process. “Essentially, the voltage and current at cell level, taking into consideration other parameters such as the operating temperature, are sent to the AVILOO data cloud via a data interface. Based on these data – up to one million data points are collected – the current state of the battery is then determined”, explained Markus Gregor further.
A web app guides the user through the test step-by-step. The customer receives the result by email after 48 hours at the latest. The certificate shows the percentage capacity of the battery still available compared to the as new condition – and thus provides important information for determining the remaining value.
While this premium SOH test will be successively introduced throughout the whole of Germany this year, TÜV SÜD is already working on the market launch of a B2B product for car dealerships and leasing companies, who would like a reliable statement on the battery state and thus determined the vehicle value in the used car business.
“The flash test was especially developed for use by B2B customers who value fast determination of the state – for example, when taking back leasing vehicles”, explained Gregor. While in the premium test, dynamic data are read out over a whole discharging cycle while the vehicle is moving, the fast check is designed to analyse data of the unstressed battery. The recording and analysis of the required data takes only a few minutes and can therefore easily be integrated into existing processes, e.g. in the car dealership. A test run on the site is not necessary.
For the flash test, the AVILOO tester is also connected to the OBD interface of the standing vehicle. After starting the test, it only takes a few minutes before a green LED in the box signals the successful end of the procedure. What looks easy for an onlooker is based on complex computing operations and on the data comparison with the data from thousands of preceding tests already stored in the AVILOO cloud.
The flash test provides statements about the following vehicle parameters:
|The progress of the test is indicated by the colours of the LEDs: LED flashes blue means the box is "waking up" and is ready for the test.||If the box flashes yellow, the AVILOO Box is looking for the FIN. Is this has been determined, the LED is constantly lit yellow.||If the box is constantly lit green, the flash test has been completed successfully; a constant red signal indicates an error.|
“The data on the different vehicle types collected in the AVILOO test laboratory and the data from the premium test are the basis for the flash test”, explains Gregor. The database is already so large that we now also trust ourselves to determine the battery state while the vehicle is stationary. The calculation of the battery state in the flash test is ultimately based on artificial intelligence (AI), which becomes increasingly better, the more vehicles are tested.
Although it is not possible to take measurements of the stressed cell while the vehicle is stopped, the voltage and temperatures at cell level can be compared with the empirical values collected in the cloud. Gregor: “We identify deviations and conspicuous voltage drifts within a battery – from this, the algorithm determines the battery state based on experience. In addition, plausibility checks are performed and the battery state is classified via the values collected. The basis is the comparison with the AVILOO battery cloud using big data algorithms.”
Directly after the test, the user receives a test report with the calculated score by email or via a data interface. Markus Gregor explained its significance: “The score is a calculated value, which correlates with the remaining range of the vehicle. The poorer the percentage is, the smaller the range that can still be achieved with the battery.” The score also reflects historical data of the battery, for example, the total energy consumption, the number of full cycles, the vehicle handling or the charging cycles. The percentage value determined is therefore a combination of current measured values and historical data. If the battery is damaged or causes a risk, a so-called “red flag” report is created, which also contains recommendations for suitable measures.
The AVILOO test is the only test available on the market that can analyse defects at cell level. The method currently covers 90 of the e-vehicle models available on the market, it should soon cover 120 models, which would include all popular e-vehicles. There is a limitation, as Markus Gregor explains: The SOH test is useful for vehicles run solely on battery electricity and for plug-in hybrids, however, not for the mild hybrid drive.
Through an extensive re-engineering process, the AVILOO experts have also managed to decipher information from the battery control units. These data provide valuable information on the battery’s use history. The process is currently being run by selected pilot customers to make it ready for the market and will probably be launched in the third quarter.
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