Battery Storage - Key Enabler for EV Charging in Multi-family Houses and Commercial Buildings

Objective: For large-scale market development of electric vehicles it is essential to enable “at home charging” not only in single family houses but also in apartment buildings. Secondly it is also crucial to prepare basement garages of commercial buildings for charging huge numbers of electric vehicles.

Methods: The integration of battery storage as a buffer into EV charging stations of multi-family houses and commercial buildings render the extension of the grid connection point and also the extension of the distribution grid. Furthermore such battery storage supports the utilization of building integrated photovoltaics for electromobility purposes and enables high fractions of local use of the generated PV electricity. In case of a building integrated CHP unit a battery storage allows the decoupling of electricity generation and charging of EVs as well.
As buffer storage, integrated into EV charging stations, 2nd use batteries are an interesting alternative to investments into new systems. Typically, batteries, which are not suitable anymore for EVs, can still be used in stationary applications as for example in the addressed charging stations. Such 2nd life concepts prolong the usable life time of batteries and therefore improve their overall CO2 footprint.
2nd use concepts need the investigation of various technical and economical topics addressing safety, reliability, performance and expected life-time as well as regulations for integrating stationary battery storage into buildings. For identifying and forecasting the technical behavior of used batteries within 2nd life applications simulated based analyses are providing valuable information by using models for the electrical, thermal and aging behavior.

Results: Within this presentation the approach and results of two building integrated battery storage examples will be shown. The first one is based on a new battery system for a mixed commercial / residential building, which is combined with building integrated PV. The second one is based on 2nd use batteries for a multi-family house, which is combined with building integrated PV and a CHP unit. In both buildings the technical concepts are enabling flexible EV charging in high numbers and utilization of local resources at the same time.

Conclusion: Integration of battery storage in multi-family houses and commercial buildings offers smart solutions for enabling EV charging and flexible coupling to locally installed power generators such as photovoltaic systems and CHP units. Based on the elaboration of an adapted system design, such concepts can avoid low voltage grid extension and extension of the grid connection points of buildings.