Lithium battery energy storage technology -Lithium - Ion Battery Equipment

Application of lithium battery technology in energy storage power plants -Lithium - Ion Battery Equipment

Lithium battery application scenarios can be divided into consumption, power and energy storage. The earliest application is in mobile phones, laptops, digital cameras and other consumer products, which currently accounts for about half of the global shipments of all types of lithium batteries. With the increase of global demand for new energy vehicles, the proportion of power lithium batteries has increased year by year, accounting for more than 40% at present. Power batteries will become the main application scenario of lithium batteries in the future. According to the standard, if the capacity of the power battery is less than 80%, it can no longer be used in new energy vehicles. However, the requirements for ordinary energy storage batteries are not so high. After the power battery is retired, it can also be used in the energy storage system with a little modification. As a new application scenario, energy storage lithium battery has also been gradually attached importance. Energy storage is one of the important means to solve the intermittent fluctuation of new energy wind power and photovoltaic, and realize the function of "peak clipping and valley leveling".(Lithium - Ion Battery Equipment)

At present, there are two mainstream energy storage lithium batteries: lithium ternary battery and lithium iron phosphate battery. The power density is much higher than that of lead carbon battery. Relatively speaking, lithium ternary battery is higher than lithium iron phosphate battery.

In the energy storage system, lithium battery, lead carbon battery and lead acid battery are all used to store electric energy, and there is no essential difference. The design and selection of battery capacity and charge discharge current are the same. Compared with lead-acid batteries, lithium battery energy storage is a new thing. At present, there is no standard product. Unlike lead-acid batteries, there are many specifications and models. Generally, manufacturers determine the specifications according to the electricity quantity. The biggest difference between lithium battery and lead-acid battery is that lithium battery must be equipped with battery management system.

BMS battery management system

Lithium batteries have the advantages of light weight, large energy storage capacity, high power, no pollution, long life, etc., but lithium batteries are very sensitive to over-current and over-voltage. Large capacity batteries are made of many small capacity single batteries (such as 18,650), which are connected in series and parallel. More parallel batteries are likely to cause unbalanced current in each branch. Therefore, a battery management system must be introduced to join in the control. The lead-acid battery has many advantages, such as good high current characteristics, low self discharge, stable performance, safety and cleanliness. At present, the daily maintenance of the lead-acid battery is mainly completed manually, mainly troubleshooting the connection status and terminal voltage of the battery, and does not require the BMS battery management system.

Battery Management System (BMS) is a device composed of microcomputer technology, detection technology, etc. It is used to dynamically monitor the operation status of battery pack and battery unit, accurately measure the remaining power of the battery, and at the same time protect the battery from charging and discharging, so that the battery can work in the best state, so as to extend its service life, reduce operating costs, and further improve the reliability of the battery pack. The battery management system of electric vehicle shall realize the following functions:

1 -- Accurately estimate the State of Charge (SOC) of the power battery pack

That is, the remaining capacity of the battery, to ensure that the SOC is maintained within a reasonable range, to prevent damage to the battery due to overcharge or overdischarge, so as to predict at any time how much energy is left in the hybrid electric vehicle energy storage battery or the state of charge of the energy storage battery.

2 --- Dynamic monitoring of the working state of the power battery pack

Ensure the safety of the battery. During the charging and discharging process of the battery, collect the terminal voltage and temperature of each battery in the electric vehicle battery pack, the charging and discharging current and the total voltage of the battery pack in real time to prevent the battery from overcharging or overdischarging.

3 -- Balance between single batteries

Namely, it is used to equalize the charging of single battery, so that each battery in the battery pack can reach a balanced and consistent state. Balance technology is the key technology of a battery energy management system that is being researched and developed by the world.



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