7 LAYERS OF ENERGY STORAGE SYSTEM

Energy storage systems can be divided into seven layers from raw materials to systems, and some of them can be divided into fewer or more layers. I suggest that you don't need to spend time tangled up in these layers. This kind of tangle can be quite useful for academic purposes, but this is mainly for your understanding. We will focus on the most widely used lithium battery energy storage systems.

 Let's unpack the storage system right now! Take a minute to look at the picture below:

The first layer of energy storage system: raw materials and battery materials

Energy storage systems need batteries as a base. The raw materials are mainly mining areas. Battery materials refer to positive electrode, negative electrode, electrolyte and diaphragm, which are not shown in the picture. It's a place where basically every producer already has a foothold, it's not easy to compete, and upstream capital intensity is high, so you have deep pockets to survive here. There may be a chance to drop in the electrolyte, diaphragm these two.

Energy storage system Layer 2: Cell

These battery materials are put together to form a battery cell. Although each design varies greatly, to put this in perspective, a 1MW storage system would have about 14,000 batteries (20 Ah, for example), which is roughly the capacity of 80,000 batteries in 10 Tesla electric cars, although the batteries used in the storage system are much larger than those used in electric cars.

In the current application scenario of electric power grid and electric vehicle, the cathode materials of lithium battery can be generally divided into three categories: lithium cobalt acid (LCO), lithium iron phosphate (LFP) and ternary material (NMC). Because of the pursuit of CP value in China, mainly lithium iron phosphate, commonly known as lithium iron battery; Japan's Panasonic and South Korea's LG/Samsung use three-component materials, commonly known as lithium three, which make them popular in the electric car market. In addition to the classification of different materials, the same brand of batteries will distinguish different specifications, grades, to adapt to different application scenarios, if not insiders, must be dazzled.

Energy storage System Layer 3: Battery Module (Pack)

Each battery cell is like a single soldier in the army, it is impossible to rely on a single soldier to move, but many battery cells can be combined together into a module, a battery module usually has at least 100 batteries, so the management is more convenient.

Module factory is responsible for this part of the assembly technology, they will build the first layer of small battery management system when making modules, and fire protection mechanism is designed to prevent the burning of battery cells, which is also an important part of the international safety certification such as IEC, UL. It's also very capital-intensive because you have economies of scale and price competitiveness, and you have to know where you're going to sell, or you're going to run out of stock.

Floor 4: Battery Cabinet and Battery Management System (Rack and BMS)

To manage battery cells and modules, a higher-level battery management system is needed. Only when the battery is given a command, it will know how to act. The battery management system will also check the status of each battery cell from time to time, and try to maintain the balance between battery cells. Most companies up to the battery cabinet level will include battery management systems as part of the service, the buyer does not need to develop their own, in case you use it carelessly and accidentally burn it, in order to compensate for the issue of people will not be finished.

Energy Storage Level 5: Power Regulator (PCS)

The power regulator is the key to connecting the battery cabinet to the grid application. It can be converted in both directions. The discharge is to convert the DC of the battery into the AC of the general power company, and the charge is to convert the AC of the general power company into the DC of the battery for storage. The machines and equipment that need to communicate with the power grid all need the function of two-way conversion. It just depends on what way to do it. For example, electric vehicles rely on charging piles and can convert alternating current into direct current or reverse direct current.

The power regulator needs to connect various communications between the battery management system and the energy management system described below, and the data acquisition and transmission volumes are quite complex. There are only a few companies selling power conditioners in Taiwan, and there are many established brands to choose from abroad, so the opportunities are relatively small.

Layer 6: Energy Management System (EMS)

Whether it is energy saving, energy innovation, energy storage, intelligent system integration, as long as it involves the integration of many electrical equipment, power generation equipment, energy storage equipment, etc., all need an energy management system, energy storage system is no exception naturally. In the energy storage system, the energy management system is a whole set of monitoring system covering the controller. In addition to managing when the power regulator charges and discharges, it also includes monitoring the ambient temperature and humidity, fire protection system, access control system and so on, which is equivalent to the brain of the energy storage system. The energy management system needs to be able to communicate with the battery management system and the power regulator. If the energy management system is not properly controlled, there may be loopholes in the safety design, which is one of the reasons for the fire accident of the energy storage battery in Korea.

Different applications require different energy management systems. Few battery or module manufacturers can reach this far, so energy management systems are one of the more promising areas. It should be noted that sometimes we will see some headlines like "EMS factory grabs business opportunities" news, then we should be careful to distinguish whether it refers to electric vehicle EMS or energy storage EMS. Electric vehicle EMS factory does electronic components for vehicles, such as the car dashboard, touch panel, etc., which is different from the energy storage EMS to communicate with the power grid.

Tier 7: Energy Storage Systems and System Integration (SI)

Buying an energy storage system is not like buying an electric car. More often than not, you need a custom design. After all, every application scenario that requires an energy storage system is different.

So you need to choose a system integrator to put the whole system together for you. Systems integrators often develop energy management systems to ensure superior execution quality for the various parts they procure.

Congratulations, you have completely understood the energy storage system!