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ASD claims new parallel connection technology will give storage companies ‘absolute freedom’

Wolfram Walter, managing director of ASD Sonnenspeicher. Image: ASD.

ASD Sonnenspeicher is preparing to put a new piece of battery technology on the market that allows cells to be connected in parallel, with the company claiming it could have a transformative effect on energy storage, batteries and EVs.

The German company, started up by founder Wolfram Walter when he developed an energy storage system for his own use that Walter claims rapidly became commercialised and quickly turned into a business, is perhaps best known for its residential storage systems. ASD makes larger scale devices as well and claims that its new product, Pacadu, could enable a user to build up to a 1GWh storage system using smaller constituent components.

Speaking to PV Tech Storage at Intersolar Europe earlier this month, Wolfram Walter claimed the parallel circuit technology used in Pacadu solves “all of the main problems” with using batteries for energy storage at present. Walter said Pacadu would also allow for different types of battery to be connected together for use within the same energy storage system.

According to Walter, “[the] batteries we have today are perfect, what we are doing with batteries is wrong”.

“Because we connect all the batteries in a series connection and the series connection causes all the problems we have today. So you cannot use the complete capacity, the weakest battery cell is determining the whole performance of the system, a broken cell in such a system, you have to throw away the complete battery and you have to stay in one technology. You cannot have two different battery technologies in one system, you cannot mix high current batteries with high capacity batteries in one system,” Walter said.

“…It’s a bi-directional system, we can charge and discharge, that we can do very, very, fast and now we are absolutely free, we can build systems where no longer the weakest cell determines the complete system.”

Walter explained that for series connected storage, where one battery had 40% of its capacity remaining out of 100 batteries, the drop in performance would cause the whole system’s performance to drop to 40%.

“If we take the same system with 100 batteries and the same 40% battery, now you have 96% capacity in the whole system, you lose 4% and not 60%. If you’d like to change this battery cell you can do that anytime, put any battery type you like in and it will run again.”

A press spokeswoman for ASD said that third party verification of the company’s claims have not yet been made available, but that “several Professors from all over the world came to visit ASD and were convinced after having seen Pacadu working successfully [for] themselves". The spokeswoman said that certification and tests by external laboratories are underway and will be made available “in the coming months”.

ASD claims new parallel connection technology will give storage companies ‘absolute freedom’

Wolfram Walter claims Pacadu (pictured) can solve the problems associated with accomodating different battery technologies in one system and with mixing high current batteries with high capacity batteries within a storage system. Image: ASD.

Walter said that he even hoped ASD’s competitors would adopt the company’s proprietary technology, drawing an analogy with anti-lock braking systems (ABS) for automobiles. The company has lofty ambitions for Pacadu, with Walter claiming to be “absolutely sure” that in a few short years, it will be the most common way storage makers configure their batteries.

“There are a lot of competitors but they are all using the old technology as we did in the past. We believe we have to bring the Pacadu technology also to all our competitors, so that they are able to build systems with that pure parallel technology to bring the market to the position it has to be.

“I’m absolutely sure in three or four years you will [see] storage systems worldwide where you see [all], or maybe 80% with a 'Pacadu Technology Inside' label on top."  

Energy storage expert Marianne Boust at research firm IHS told PV Tech Storage that some other companies have already started offering parallel connection for batteries in other markets that include California and Australia. Aqueous flow battery manufacturer Aquion is one such example. However, she said, some of the other advantages Pacadu appeared to offer made the product an interesting innovation.

“…It’s interesting to look at the Pacadu innovation they’ve introduced, enabling them to have better information on the battery cells and giving the flexibility to the consumers to change one cell and not the entire battery, and from a different provider.

“Battery lifetime is a major weakness to the deployment of batteries and this feature should help extend the battery duration,” Boust said.

Another interesting aspect of Pacadu’s launch, which could be an indication of what lies ahead for energy storage systems, according to Boust, was that it “underscores the fierce competition among battery providers".

“It’s not enough to provide cheaper batteries. Competition is also on to increase reliability and safety of the system. We’re expecting more of these announcements in the months to come as more players pop up on the market.”

ASD claims new parallel connection technology will give storage companies ‘absolute freedom’

ASD's residential storage system shows power flows to and from different sources as differently coloured, moving stripes of light on the box's exterior. Image: ASD.

Tags: solar-plus-storage, lithium iron phosphate, innovation, parallel connection, bi-directional, battery