Research in the Department of Mechanical Engineering
UA develops innovative technology to store and give mobility to electricity
Tecnologia vai ao encontro dos condutores que optaram por um carro elétrico
It is called Modular Device for Energy Storage (DMAE) and aims at reducing the resistance to opt for electric cars. Oversimplifying, it consists of a metal structure that houses lithium-ion batteries - the same as used in electric cars - and that is mobile as it is on a truck. Developed in the Department of Mechanical Engineering (DEM) of the University of Aveiro (UA), the Management and Control System of DMAE is the brain that makes the innovative features of the device feasible.

To reduce waiting times to load the car, overcome the limitations arising from the power grid and enable business models arising from the storage of electricity, will be the distinctive features of this technology, that by being mobile, can meet the needs of the drivers who opt for an ecological car as well as allow the electricity storage in any renewable energy production site.

DMAE will be an electric truck that stores energy, such as a tanker stores fossil fuel. Although dependent on the type and capacity of the batteries inserted into the DMAE, the idea is that it will be able to supply simultaneously ten electric cars in fast mode. That is, until ten vehicles can at the same time be loading 80 percent of the capacity of their battery, a higher percentage than what happens currently in the national electric charging network.

The total number of electric vehicles that can be fueled by a load of DMAE depends on the energy stored and also on the load condition of the vehicles, but , in average, the department  ensures that DMAE can load at least three dozen vehicles.

"The batteries inserted in the device are interconnected by an intelligent electronic power network, forming a dynamic array of batteries," explains José Santos. The researcher responsible for developing the Management and Control System of DMAE explains that "the array is dynamic because the interconnections inside and the links with the exterior of the device are monitored and managed by the Management and Control System in real time." DMAE can thus perform multiple functions with the energy it stores.

The project, partially supported by a QREN Innovation voucher, had the duration of a year and was developed in partnership with the company D2M-Energytransit, which owns the patent for DMAE. The results of the tests performed with the prototype built met the expectations of the company and confirm the innovative properties of DMAE.

The electricity storage is an old ambition of the electric sector and, as explained by the DEM researcher, "the advantage of DMAE concept, is that the considerable storage capacity [up to 4 MWh with the best electric vehicles batteries currently], is not the result of a large battery built from scratch, but rather the grouping of existing batteries. "The costs are therefore "notoriously lower".

Considering the association of DMAE concept to the swap stations model (already present in some countries), where the cars exchange the battery instead of waiting for the partial loading, the modularity of the device shows greater advantage. By rotating the batteries inserted in it (resulting from the swap station exchanges), the lifetime of DMAE increases greatly, increasing its sustainability. 

Drivers are doubly benefitted, because the time to restore the full autonomy (estimated less than five minutes to the exchange operation) is reduced, as well as the limitation of autonomy, the main concern for drivers.