How does a mobile battery work?

The container – The packaging

The outer shell of the battery must be sturdy and weather-resistant since mobile batteries can be used at all kinds of locations with widely varying weather conditions. An example of this is the container we use at Greener, which is a 10 feet sea container. This type of container is not only suited for projects on land but can also be used for offshore projects if necessary. Additionally, the size of 10 feet is suitable for modular use and can be relocated easily. With a weight of 8.2 tons the container is heavy, but still manageable for transport.

Another important part of the container is the air-conditioning. All devices inside the container need to be kept at operating temperature to ensure an optimal process. Different technologies, such as a liquid-cooling system, can be used to enhance the air conditioning and to ensure operating temperatures. In the case of the system installed in Greener batteries safe operating temperatures can be provided even at extreme external temperatures from -20 to +40 °C.

The batteries – The DC energy storage

The heart of the energy storage system consists of the batteries. Different types of batteries can be used, which vary in size, weight, and efficiency. To name an example, Greener is using lithium-ion batteries, which are EV batteries. To be exact, the batteries you can find in the BMW i3 series can also be found in our mobile batteries. This ensures high safety due to the testing measures for EV batteries and means that these batteries are safe for relocation and movement. Additionally, the battery system can be charged and discharged within one hour (depending on the available power). The quick (dis)charge ensures that peaks of electricity can be met without problems.

Since the batteries can be used to counter imbalances in the energy market, the capacity and power of the energy storage system were chosen in accordance with that goal, as well as an affordable price in mind. While the battery systems currently in the market do have a higher price in comparison with diesel generators, the operational costs are lower due to the developed software and no need for a diesel generator running on diesel 24/7. This low operational cost makes batteries a cost-efficient option for many projects. Additionally, to the cost benefit on the long term, the lower CO2 and nitrogen emissions together with a low disturbance factor can be advantageous.

The computer – The brain

The computer is located within the container and is the control system of the batteries. Here, the software and different controlling options can differ quite widely considering the supplier of the mobile battery. At Greener, different options are available for the client when monitoring and controlling the energy storage system. Using our local operating system, the Human-Machine-Interface (HMI), commands can be given, and important information is displayed. Next to our local controlling system, we also offer controlling from a distance, since we have developed our software to work with the messenger Telegram, as well as our Energy Management System. This ensures supervision of all operations at all times. Since the computer installed within the battery system keeps track of all information, including the information of any connected energy sources (such as a generator or solar panels), reports with detailed numbers about energy consumption and the savings of CO2- and nitrogen-emissions are included in the service. This data can be used to improve the accuracy of future power plans and have full insight into the electricity consumption. Additionally, all data is tracked and processed in our online dashboards, which give the clients, as well as Greener employees, real time and historical insight into the data.

The inverter – The AC part

The inverter is responsible for converting the electricity from AC to DC and the other way around. Regarding the input of the battery, the electricity can be supplied for instance by a diesel generator or a grid connection, which deliver AC electricity. This needs to be converted to DC electricity to be stored in the batteries. When no external energy source is connected the battery exclusively uses the electricity stored in the lithium-ion batteries and creates its own grid. The inverter then converts this electricity for the output and different net filters optimize the AC electricity to ensure that the energy is suitable for all energy users on the output.

Many different applications are possible on the output, such as powering appliances at a construction site or supplying electricity for food stands at a festival. AC and DC work together seamlessly due to the inverter to supply powerful energy in a suitable form.

For our Greener batteries we use an inverter by the brand Vacon with a capacity of 285 kW.