Solar power storage systems are on the rise globally – BloombergNEF recently reported a growth rate between 70 and 150 percent worldwide. But these systems are only as good as the batteries within them (typically lithium-ion), and quality standards for the battery units are neither well-developed nor standardized across manufacturers, the majority of which are based in Asia.

The Photovoltaic Institute (PI) Berlin, an independent expert for the construction and operation of PV power plants, has therefore developed a method for thoroughly investigating the production of batteries for solar storage anywhere in the world. This development is good news for the solar industry as it provides more security for investors in and operators of solar parks and systems.

"Batteries represent the greatest safety risk in any energy storage system. Recent cases of insufficiently performing storage systems have highlighted this risk," explains Ian Gregory, managing director of PI Berlin's North American office, in a press release. Poorly produced and inadequately tested batteries not only lead to falling performance, but also safety risks. And it is very hard to identify battery defects within a finished storage system.

"On the way to the finished battery there is a lot of room for error,” explains Gregory. “Our audit identifies the weak points in the manufacturing process.” For example, the chemical electrolytes must be sufficiently pure, the electrode coatings must be totally uniform, and all raw materials must be stored and processed at the right temperature and humidity. Only when all the manufacturing steps are carried out correctly will the battery be reliable.

The PI factory audits check and compare over 170 processes and materials. In order to remain independent, factories won’t be able to commission an audit themselves, but they can ask their customers to request one.