Concept of energy storage system with renewable energy

PREDICTIVE BATTERY ANALYTICS SOFTWARE

This Software determines how Healthy Expensive Batteries still are

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The Munich-based startup TWAICE ensures longer life and lower costs for modern energy storage devices with a digital twin

The battery is by far the most expensive component in electric vehicles. But of all things, when it comes to valuable energy storage, the developers usually do not know how much it is really stressed and worn out in everyday use. The two engineers Stephan Rohr and Michael Baumann recognized this when they researched their PhD thesis four years ago.  But the researchers did not want to accept it. They developed software that allows insights into the actual processes within each battery. Like this, you always get information about the “health” of the battery.

The engineers founded the startup TWAICE and their idea directly hit a gap in the market. Not only car and scooter manufacturers are interested in their “digital twin” today. The manufacturers of electrical machines and tools also urgently want to know how their batteries behave during operation. The innovative application helps to accelerate the development of electric mobility because it reduces the costs of the batteries and extends their life.

Originally, Rohr and Baumann wanted to find out how lithium-ion batteries could be used in other areas before recycling when they are no longer powerful enough for the mobility application. To enable this so-called Second Life, however, one must know in which state a battery is after its primary application. “We then discovered that manufacturers often hardly could tell how the batteries are stressed during use,” says Baumann. For example, in cold Norway, cell chemistry suffers more than in milder southern Germany. This is to be suspected, but the actual ageing behaviour of a battery was a big mystery so far.

However, the remaining life of an energy store is critical to the viability of potential secondary use. Only the digital twin from TWAICE allows precise insights into the battery. The software even provides predictions for the future.

How long will the storage last, what is needed to extend its life, how much capacity does the battery have left? Such questions can be answered when the program monitors ongoing operations and draws conclusions. “We deliver transparency to our customers,” explains Michael Baumann. As a big plus, he sees the independence of TWAICE: “When a battery manufacturer provides information on his own product, these may be one-sided. We, however, use a neutral procedure – no matter who built the battery.”

The digital twin itself can essentially be thought of as a model-based image of the actual battery. It is continuously fed with measurement data from the operation. Thus, one always knows the current state of the battery system and can predict further ageing. This knowledge helps in two major areas: developing a battery and monitoring its operation.

To determine the health of a battery, the TWAICE software handles many factors that affect its life and performance, such as the way the battery is charged. Fast charging, especially in the cold, wears the chemistry faster than a gentle charging process. The program considers such ageing factors as well as weather and geodata.

The TWAICE forecasts, for example, benefit fleet managers who are increasingly managing electric cars. You can now view the status of each car battery live on the screen and optimize its maintenance and use.

The use of vehicle batteries as power storage are also facilitated by the information. Adding excess electricity to the grid can be a lucrative additional business for companies with many e-cars.

A clear benefit of the software becomes visible with the example of battery wear during winter operation. This knowledge could benefit a sharing provider of electric scooters. He calculates in advance whether the two-wheelers in winter rather stay in the camp. This would be useful if the expected business at this time is lower than the predicted battery damage.

However, TWAICE development is not just benefiting electromobility. The digital twin also makes sense for the increasingly important stationary power storage systems. “If the operating strategy of such a battery is changed over to a new mode after some time, the operator wants to know in advance the consequences for the lifetime”, says Rohr.

Companies are increasingly using this new transparency when designing batteries. “A developer, for example, can see how installing a cooling system would affect battery life. Then he adapts the design accordingly”, Rohr explains. This saves on development costs because the engineers can react long before the start of production. And they avoid a common mistake: Batteries have been oversized by the manufacturers often so far because they lack information on the actual battery degradation. “Up to 30 per cent too big,” excess capacity today, adds Stephan Rohr. The industry simply lacks precise measurement methods to find the right dimension for their application. Given the expensive batteries, this error can easily add up to costs of 1000 euros and more per car.

And the speed of development of vehicles and tools is also accelerating with the help of the digital twin. “The development of batteries and cells is progressing rapidly. It’s important not to lag behind in the application”, say the TWAICE founders.

Autor: TWAICE
Published: 21st January 2019
Location: Munich