Ⅰ. The necessity of battery energy storage system
Electric energy storage technology is very important for realizing the basic functions of microgrids. The reasons why microgrids need to store electric energy are mainly due to the following four reasons.
1. In order to ensure the reliability of the power supply system;
2. In order to ensure the quality of power supply;
3. In order to improve the comprehensive utilization efficiency of electric energy;
4. In order to improve the grid-connected performance of various new energy sources. Therefore, a high-performance battery energy storage system is a powerful guarantee for the microgrid to realize its own functions.
Ⅱ. The electrochemical principle of lithium iron phosphate battery
The positive electrode material of the lithium iron phosphate battery is lithium iron phosphate (a peroxy compound of lithium), and the negative electrode material is graphite or coke. The lithium iron phosphate battery is a kind of lithium battery, which is named after the positive electrode material of the lithium iron phosphate battery.
Ⅲ. The characteristics of lithium iron phosphate battery
1. High energy density
Energy density can express how much energy is stored per unit volume or weight. The energy density of an electrochemical cell refers to the electrical energy that can be supplied to an external load per unit volume or mass of the battery.
Under the same weight, the energy density of the lithium iron phosphate battery is 3 to 5 times that of the lead-acid battery, that is to say, when the rated capacity of the battery is the same, the lithium iron phosphate battery will be much lighter than the lead-acid battery, and it is also relatively reduced. Requirements for support strength.
2. Long service life
The life of a recyclable battery refers to the number of cycles that the battery can be charged and discharged normally, and the life of a lead-acid battery is about 500 times.
The life of lithium iron phosphate batteries can reach 1600 times, and the capacity can be maintained at 80%. The life of lithium iron phosphate batteries is significantly better than that of lead-acid batteries.
The safety of lithium batteries has always been a key reason for hindering their development, while lithium iron phosphate batteries completely solve the instability factors of lithium compounds. Lithium cobaltate and lithium manganate will explode under specific conditions, such as collisions.
The lithium iron phosphate battery has been carefully designed and passed strict performance tests and safety tests, and will not explode under severe collisions, penetrations, etc.
4. No memory effect
If the rechargeable and dischargeable battery is fully charged for a long time and not used, its capacity will be relatively lower than the rated capacity value, which is the memory effect. Lead-acid batteries have obvious memory effects, and lithium iron phosphate batteries have basically no memory effects after testing.
At a time when technologies such as fuel cells, vanadium batteries, and flywheel energy storage are not yet mature, and the shortcomings of traditional lead-acid batteries are becoming more and more obvious, lithium iron phosphate batteries, as the representative of the current electrochemical battery technology, have gradually matured, and their applications have also become more and more mature. gradually gained popularity.
National policy support has accelerated the development of lithium iron phosphate batteries, and the price of lithium iron phosphate batteries will gradually decrease in the future development and popularization.
Lithium iron phosphate battery will become the mainstream battery in the future energy storage system with its superior performance, inject fresh blood into the microgrid energy storage system, and further improve the overall performance of the microgrid.