Keyword search: battery plant , lithium battery factory , power bank works , lifepo4 battery mill , lithium forklift battery manufacturer

1. Application scenarios of large-scale energy storage systems

New energy power plants, wind or solar power plants, are increasingly equipped with energy storage systems to achieve the goal of smoothing output power fluctuations.

Independent energy storage power stations have gradually entered people's vision with the reform of the power system, and independent energy storage power stations that make a living by reselling electricity have gradually emerged.

A microgrid is a small power supply and distribution network that includes distributed power sources, electricity loads, energy storage systems, and grid management systems within the system. In order to ensure the continuity and stability of power consumption for the load, each microgrid will be equipped with an energy storage system.

Indoor energy storage power station

2. Differences between Energy Storage Battery Management System (ESBMS) and Power lithium battery Management System (BMS)

The energy storage battery management system is very similar to the power lithium battery management system. However, the power lithium battery system is located in high-speed electric vehicles, and there are higher requirements for the power response speed and power characteristics of the battery, SOC estimation accuracy, and the number of state parameter calculations.

The scale of energy storage systems is extremely large, and there is a significant difference between centralized battery management systems and energy storage battery management systems. Here, we will only compare the distributed battery management system for power lithium batteries.

2.1 The position of batteries and their management systems varies within their respective systems.

In energy storage systems, the energy storage battery only interacts with the energy storage inverter on high voltage, which takes power from the AC power grid and charges the battery pack; Alternatively, the battery pack can provide power to the inverter, which converts electrical energy into AC and sends it to the AC power grid.

The communication of the energy storage system and the battery management system are closely related to the information exchange between the inverter and the scheduling system of the energy storage power station. On the one hand, the battery management system sends important status information to the inverter to determine the high-voltage power interaction situation; On the other hand, the battery management system sends the most comprehensive monitoring information to the scheduling system PCS of the energy storage power station. As shown in the following figure.

Basic topology of energy storage systems

The BMS of electric vehicles has an energy exchange relationship with both the electric motor and charger at high voltage; In terms of communication, there is information exchange with the charger during the charging process, and in all application processes, there is the most detailed information exchange with the vehicle controller. As shown in the following figure.

Electrical topology of electric vehicles

2.2 Different hardware logic structures

The energy storage management system generally adopts a two-layer or three-layer hardware model, and larger scale systems tend to have a three-layer management system, as shown in the following figure.

Block diagram of three-layer energy storage battery management system

The power lithium battery management system has only one centralized or two distributed layer, and there is basically no situation of three layers. A centralized battery management system is an important application for small cars. A two-layer distributed power lithium battery management system, as shown in the following figure.

Block diagram of distributed electric vehicle battery management system

From a functional perspective, the first and second layer modules of the energy storage battery management system are basically equivalent to the first layer acquisition module and the second layer main control module of the power lithium battery. The third layer of the energy storage battery management system is an additional layer added on this basis to cope with the huge scale of energy storage batteries.

Make an inappropriate analogy. The optimal number of subordinates for a manager is 7. If the department continues to expand and there are 49 people, then the only option is for 7 people to choose a team leader and appoint a manager to manage these 7 team leaders. Beyond personal abilities, management is prone to confusion.

Mapping to the energy storage battery management system, this management capability refers to the computing power of the chip and the complexity of the software program.

2.3 Differences in communication protocols

The communication between the energy storage battery management system and the internal system is mostly based on the CAN protocol, but its communication with the external system, specifically the energy storage power plant dispatch system PCS, often uses the Internet protocol format TCP/IP protocol.

Power lithium batteries are used in the electric vehicle environment using the CAN protocol, but internal CAN is used between the components inside the battery pack, and the whole vehicle CAN is used to distinguish between the battery pack and the vehicle.

2.4 Different types of battery cells used in energy storage power stations result in significant differences in management system parameters.

For safety and economic considerations, when choosing lithium-ion batteries for energy storage stations, lithium iron phosphate is often chosen, and some energy storage stations use lead-acid batteries and lead-carbon batteries. The current mainstream battery types for electric vehicles are lithium iron phosphate batteries and ternary lithium-ion batteries.

The different types of batteries result in significant differences in their external characteristics, making battery models completely unusable. The battery management system and battery cell parameters must have a one-to-one correspondence. The detailed parameter settings for the same type of battery cell produced by different manufacturers may not be the same.

2.5 Different tendencies in threshold setting

Energy storage power stations have relatively abundant space and can accommodate a large number of batteries, but some power stations are located in remote areas and transportation is inconvenient, making large-scale battery replacement difficult. The expectation of energy storage stations for battery cells is to have a long lifespan and not to malfunction. Based on this, the upper limit of its working current will be set relatively low to prevent the battery cell from working at full load. Do not have particularly high requirements for the energy and power characteristics of battery cells. It's important to consider the cost-effectiveness.

Power lithium batteries are different. In the limited space of a vehicle, the battery that is finally installed hopes to maximize its capabilities. Therefore, system parameters will refer to the limit parameters of the battery, and such application conditions are harsh for the battery.

2.6 The two require different numbers of state parameters to be calculated

SOC is a state parameter that needs to be calculated for both. But until today, there is no unified requirement for energy storage systems, and the energy storage battery management system must have the ability to calculate what state parameters. In addition, the application environment of energy storage batteries has relatively abundant space, stable environment, and small deviations are not easily perceived by people in large systems. Therefore, the computing power requirement of the energy storage battery management system is relatively lower than that of the power lithium battery management system, and the corresponding single string battery management cost is not as high as that of the power lithium battery.

2.7 Energy storage battery management system application has better passive balancing conditions

The demand for the balance ability of management systems in energy storage power stations is very urgent. The scale of energy storage battery modules is relatively large. Multiple series batteries are connected in series, and a large voltage difference between individual cells will cause a decrease in the capacity of the entire box. The more batteries connected in series, the more capacity they will lose. From an economic efficiency perspective, energy storage power stations need to be fully balanced.

Furthermore, due to the abundant space and good heat dissipation conditions, passive balancing can better exert its effectiveness. By using a relatively large balancing current, there is no need to worry about excessive temperature rise. Low priced passive equilibrium can showcase its strength in energy storage power stations. 60 ℃ is the upper limit of the allowable working temperature range for general lithium-ion batteries. Electrochemical reactions are carried out at higher temperatures, and the electrolyte has strong activity and is prone to decomposition reactions. The decomposition products combine with the positive electrode material, which consumes the positive electrode material; The positive electrode structure material is corroded, and the lattice structure collapses due to the lack of sufficient material support, reducing the vacancies of lithium ions and decreasing the ability of the positive electrode to accommodate lithium ions, resulting in a loss of battery capacity;

Meanwhile, the products reflected by the positive electrode material may wander in the electrolyte and adhere to the surface of the positive and negative electrodes. The surface of the electrode is covered by substances that cannot participate in the charging and discharging process, which hinders the smooth occurrence of the electrochemical process and increases the internal resistance of the battery cell.

The impact of high temperature process on aging is mainly on the positive electrode, with a relatively small impact on the negative electrode.

Lithium ForkLift Batteries ,Ensure Quality

Our lithium battery production line has a complete and scientific quality management system

Ensure the product quality of lithium batteries

Years of experience in producing lithium forklift batteries

Focus on the production of lithium batteries

WE PROMISE TO MAKE EVERY LITHIUM BATTERY WELL

We have a comprehensive explanation of lithium batteries

QUALIFICATION CERTIFICATE

THE QUALITY OF COMPLIANCE PROVIDES GUARANTEE FOR CUSTOMERS

MULTIPLE QUALIFICATION CERTIFICATES TO ENSURE STABLE PRODUCT QUALITY

Providing customers with professional and assured products is the guarantee of our continuous progress.

Applicable brands of our products