Kreisel aims to put Tesla through its paces

Kreisel today launches a residential battery with improvements developed for the automotive sector. Pic: Kreisel.

Kreisel today launches a residential battery with improvements developed for the automotive sector. Pic: Kreisel.








By Jason Deign

Kreisel Electric has become the latest battery vendor to take on the Tesla Powerwall with the launch of a residential energy storage product today.

The Austrian industrial firm is looking to improve on Tesla’s trailblazing battery pack with a system that uses the same 18650-size lithium-ion cells, with a few significant manufacturing improvements.

Critically, Kreisel uses a laser system to solder connections to each cell in the battery. This is in contrast to traditional manufacturing processes where welding is employed.

The heat generated from the welding process damages cells before they are even used, said Christian Schlögl, head of business development. “With our laser technology we don’t destroy the cell,” he told Energy Storage Report.

The laser manufacturing process helps make sure all of the 8,000 or so cells in each battery have the same capacity and voltage once connected, so there is no need to balance them afterwards.

Increase in battery capacity

Schlögl said this helps increase the battery capacity to up to 95%, while the Powerwall only has a warranted capacity of up to 85%, and then just for the first two years.

The Powerwall’s charge rate is also limited by the fact that power inputs in excess of 120kW could cause the thin wires connecting each cell to overheat, according to Schlögl.

Kreisel’s Mavero battery system cells, on the other hand, are connected by a flat plat made of an undisclosed substance that reduces internal resistance and allows charging and discharging at up to 300kW, without overheating.

This means the Mavero can be charged 2.5 times more quickly than a Powerwall, said Schlögl. When discharging, “we can suck out 15% more than Tesla, from the same cell, due to the [lower] inner resistance,” he said.

Another novel design feature of the product is liquid cooling, which maintains the cells at a steady 30ºC. The fact that the cells are immersed in the liquid allows for very precise temperature control.

Charge-discharge cycles degrading cells

Once more this is in contrast to the Powerwall, where heating caused by each charge-discharge cycle further degrades the cells, said Schlögl.

The liquid, a non-toxic, non-flammable coolant provided by 3M, reduces the fire hazard associated with lithium-ion chemistries.

It also helps increase the life span of the battery by between 10 and 15% compared to other systems, Schlögl said. The 4kW Mavero is initially being offered with a 10-year warranty and more than 5,000 cycles.

It will come in 10 and 14kWh variants and multiples thereof, and can be containerised for up to 2MWh of capacity.

The 10kWh battery has a usable capacity of 8kWh, weighs around 60kg, and will be priced at around €5,000 without VAT and installation, which could bring the total price up to €6,500.

Installed within a couple of hours

The 14kWh product, meanwhile, weighs about 90kg, has a usable capacity of 11kWh, and will cost around €500 more. Both are designed to be installed within a couple of hours and can work with any inverter, Schlögl commented.

Kriesel is planning to sell around 1,000 units this year, to what Schlögl described as ‘friendly customers’, before making the product more widely available in Germany and Austria from the beginning of 2017.

Schlögl said the patented manufacturing process, which is the result of a €4m research and development programme, has resulted in one of the best price-performance ratios of any battery on the market.

Kreisel expects to be able to produce batteries at a price point below €200 per kWh with full production of around 1,000 units per year.

Kreisel originally developed its technology for the electric vehicle market, managing to cram 55.7kWh of storage capacity, with liquid cooling, into a 24kWh Volkswagen battery casing while reducing total weight by 9kg.

Double the capacity with lower weight

“In the case of Volkswagen, we can more than double the capacity with lower weight, in the same space,” Schlögl commented.

The company also lists Audi, BMW, Fendt, Magna, McLaren, Mercedes-Benz, Polaris and Porsche among its automotive clients.

For now, Kreisel is still producing prototype batteries by hand. A new, privately funded €12m production facility is expected to start up in March next year, with a capacity of 1.2m kWh.

Schlögl claimed the production capacity for next year is already fully booked.

As well as the Mavero, Kreisel will be producing batteries for a number of electric vehicle applications, including an as-yet unnamed van based on a Mercedes-Benz Sprinter chassis.

Kreisel hopes to produce 2,000 of the €90,000 vans next year, with a 90kWh battery yielding a 300km range. Kreisel is also hoping to licence the manufacturing process to other original equipment manufacturers.

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