January 19, 2024

Understanding the Mechanics of Energy Storage Systems


Energy storage systems enable consumers to be less dependent on the power grid by storing electricity during high-demand periods. They also allow individuals to quickly control their electricity consumption while reducing their carbon footprint.


This technology’s key components are batteries, inverters, and a control system. C3controls provides world-class products needed to produce these systems, including Surge Protective Devices, Contactors, Terminal Blocks, and DIN Rail.

Power Conversion System

Energy storage systems operate on multiple fronts. They contribute to grid stability, enabling communities to manage electricity production and pricing. These systems also offer backup power solutions across various scales, from daily home backup to real-time power quality maintenance for industrial processes. Additionally, they enhance renewables’ affordability by adjusting peak load times or mitigating the impact of high tariffs during specific hours.

As for the question “how do energy storage systems work,” these systems function by storing excess energy during periods of low demand and releasing it during peak demand. This process helps balance the electricity grid and ensures a reliable and steady power supply.

The power conversion system, or PCS, is the heart of energy storage systems. It is the intermediary between the storage element – large banks of DC batteries of different chemistries – and the power grid. It carries out the bidirectional reversible AC/DC conversion of currents. It can track the power generation of the battery and the grid, manage the charging and discharging of the batteries, and control the microgrid’s voltage.

As a result, the PCS is one of the most critical components for the whole ESS. The technology used in the PCS varies from device to device. For example, some use pulse-width modulated modular multilevel converters (PWM). This converter is used to improve the battery’s efficiency and reduce cost. It is also more reliable than a conventional DC-DC converter. It is resilient to both high temperatures and large loads. It is also more compact than traditional inverters.

Energy Management System

A high-level energy management system (EMS) is responsible for determining the most effective dispatch strategy to maximize the performance of an ESS, such as peak load shifting, valley filling, demand control, and off-grid backup. EMS coordinates onsite components with the battery management system (BMS) and power conversion system.

A scalable EMS is the heart of an energy storage system, providing robust monitoring and communication across all onsite equipment. It integrates seamlessly at the system level with various devices, including PCS and BMS, air conditioners, electricity meters, intelligent circuit breakers, and fire control hosts, to collect real-time data, display device alarm information, and support equipment control.

Due to its various benefits, energy storage systems are becoming increasingly popular with consumers, both residential and commercial. They can cut electricity costs, reduce reliance on the grid, boost energy self-sufficiency, and contribute to a more sustainable world.

A good EMS can spot energy usage trends and offer cost-saving solutions to help businesses/properties save money on their power bill. Additionally, it can provide revenue-generating programs and detect any potential energy leaks. The system can also help companies meet their reporting duties regarding sustainability by providing comprehensive analytics. These analytics can be displayed on a web-based dashboard to give visibility to the entire facility and encourage a more efficient approach to power consumption.

Battery Packs

A battery pack consists of lithium-ion batteries wired in series and parallel with other components like thermal management systems, safety components, and electrical interconnections. Some manufacturers design packs divided into modules that can be removed for repair and replacement. Others prefer to manufacture packs held together in one piece to diminish production costs and improve performance.

There’s also a range of cell chemistries, each offering unique advantages for different applications. Some chemistries are better at handling high-voltage, while others excel at providing a higher capacity in smaller cells.

Many BESS applications benefit from storing electricity at low prices when it’s abundant and then releasing it later for a higher price. Some examples of this include power peak shaving and energy arbitrage.

BESSes are often used to manage energy peaks in the National Grid and other electricity systems, replacing fossil-fuel-powered plants during those hours. They can also help to reduce consumers’ electricity bills through energy storage.

Building a battery pack requires careful attention to detail. For example, adjacent cells mustn’t be short. This can happen if the cases of some batteries rub against each other or if the shrink wrap or film gets brittle and breaks. For this reason, TIMs (thermal interface materials) are used to ensure an adequate electrical separation between cells.

Battery Discharge

Systems for storing battery energy provide a variety of workable answers to the problems that renewable energy sources present. These include promoting a continuous flow of power when the supply dips, helping to combat peak times and higher energy rates, and providing a backup source of electricity during blackouts.

BESSs are often used with solar power installations, electric vehicles, and smart homes. Their most important characteristic is that they can store electrical energy for use at a later time. This helps to prevent interruptions in the flow of electricity and facilitates the transition away from reliance on fossil fuels.

Chemical potential changes between the battery cells’ plates are how energy is stored in batteries. Regular charging and discharging cycles can easily convert this energy to usable energy.

During the discharge process, it is essential to know how the battery/cell is performing and what its current capacity is at that time. This is best accomplished by testing the battery using a constant current. It is also a good idea to set a timer so that the test duration can be easily tracked. Data logging may also be necessary, although this can add to the overall test duration and should be kept to a minimum to avoid short-circuiting the battery.

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