Two Greener batteries with the old and the new branding

How does a mobile battery work?

Technology is evolving rapidly nowadays. And while most people have gained a basic understanding of how the battery of their smartphone or electric car works, bigger mobile batteries still seem like a mystery. To gain clarity about the inner workings of these energy storage systems, we will explore their most important aspects.

To investigate further how an actual battery works, we first must look at all the different parts of the mobile battery:

  • The container – The packaging
  • The batteries – The DC energy storage
  • The computer – The brain
  • The inverter – The AC part

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.

The inside of a mobile battery

In this picture you can see the four different parts of the battery and how they are arranged on the inside of the battery container.

Set-up possibilities

Knowing what the batteries are capable of, they can be used in a variety of combinations:

  • As a stand-alone solution: This can be the case for projects with a low energy demand, which run for a limited amount of time or with a high energy demand, where the battery can be replaced easily. This option is only advised if there is no other possible energy source to be used and the electricity, which the battery supplies, is exceeding the demand by far.
  • Solar panels or wind energy: Solar panels and wind turbines are the perfect partner for a mobile battery. They deliver sustainable energy, which can be stored in the battery in case it is not needed right away.
  • Grid connection: Ideally, a grid connection is available. If a bigger grid connection was requested and is not available on time, a mobile battery is a fitting solution. While a small grid connection might not be able to supply enough electricity for high electricity peaks, the battery can be used as a buffer in between and is charged by the grid connection to deliver peak power without a problem.
  • Generator: There are different options for the generators, which can be used in combination with a battery, such as a diesel generator. When a battery is connected to a diesel generator, the battery supplies the electricity, and the diesel generator is only turned on when the battery needs to be charged. The battery makes sure that the genset runs at its optimal power when switched on, so all inefficiencies are filtered out. This reduces running hours and saves up to 60% of fuel and emissions.

Other generator options are to use hydrotreated vegetable oil (HVO) diesel or formic acid to further increase the sustainability aspect. Furthermore, hydrogen can also be combined with mobile batteries. There is a high flexibility for different energy sources, especially for tailor-made solutions, where the software can be adjusted accordingly.

There are different combinations possible for the set-up, as well as the combination of multiple batteries according to the needs of the situation.

While the big brother of our smartphone battery does not only increase in size, but also in power, the actual battery is similar in its use. Both types of battery reliably store electricity after being charged to use at another time. And most smartphones these days also provide an overview of the used energy to ensure an optimal use. However, mobile batteries are industry-grade and therefore built with high-resistance materials, as well as a climate-control system. Additionally, batteries are applicable in many situations, while a smartphone battery is an energy storage solely for the smartphone. In this way, mobile batteries contribute to a clean and efficient energy supply – everywhere.