Lithium-ion batteries can be very efficient, reliable and safe energy storage systems. They are able to compensate the fluctuations of renewable energy and are thus key elements for a safe and economically viable energy supply within the German "Energiewende". However, in practice and with regards to standardization there are critical safety loopholes in stationary storage systems, among those also PV home storage systems. There are also no standardized and sufficiently meaningful tests of the cycle life of these products.
You can find further information concerning safety here for download:
Summary standards and regulations
Service portfolio of KIT on battery safety
Checklist for Li-ion home storage systems