The unique feature of solar LiFePo4 battery (lithium iron phosphate battery) is the use of olive crystal structure, crystal is the shape after crystallization, divided into ionic / molecular / atomic / metal crystal, lithium-ion battery ionic crystal is taken from its cathode material in the arrangement of ionic compounds in the shape of the meaning, that is, by the positive and negative ion group in a certain proportion of the crystal formed by ionic bonding. Generally speaking, ionic crystals are brittle and hard, with high melting and boiling point characteristics, and can conduct electricity when molten or dissolved. The basis of all lithium-ion batteries, including lithium iron phosphate technology, is ionic conductivity.
Most of the internal crystal structure of the lithium-ion battery cathode takes a "spinel structure" arrangement, lithium manganate, lithium cobaltate, ternary lithium batteries are such, this structure consists of eight small cubic units composed of spinel cells (the units that make up the crystal, can be literally understood as crystal cells), the cells are then combined into an octahedral crystal structure. In contrast, the olive structure of lithium iron phosphate crystals are short columns.
The spinel structure of the above three lithium batteries have their own characteristics. Lithium cobalt-acid batteries have excellent overall performance, but low capacity and safety problems, and are more expensive to market; lithium manganate batteries because of good access to materials, low cost and safety, but poor cycle performance and storage performance; ternary lithium batteries are intended to reconcile the shortcomings of the two, the capacity has increased, and the stability of the structure has improved safety, but the price is still relatively expensive, because it also requires strategic raw materials cobalt. The general disadvantage of the spinel lithium-ion battery is that the power is not large, not suitable for large-scale.
Solar LiFePo4 battery technology features and economics, on the other hand, is just right for the home energy storage market scenario. Specifically.
1. solar LiFePo4 battery voltage is moderate: nominal voltage 3.2V, termination charging voltage 3.6V, termination discharge voltage 2.0V.
2. high theoretical capacity, with an energy density of 170mAh/g.
3. good thermal stability and high temperature resistance.
4. moderate energy storage, cathode material compatible with most electrolyte systems.
5. termination voltage of 2.0V, which can discharge more capacity, large and balanced discharge.
6. Good voltage platform characteristics, and the balance of its charging and discharging voltage platform can be close to that of a regulated power supply.
The above technical features make high power and safety ideal to achieve, which strongly promote the application of large-scale LiFePo4 battery.
In addition to technical characteristics, LiFePo4 batteries have two marketable advantages: 1. cheap raw materials, abundant resources; 2. does not contain precious metals, non-toxic, is an environmentally friendly product. This makes lithium iron phosphate battery applications in the current new energy vehicle market shine, and become the preferred energy storage technology for home solar storage systems.
1. Large capacity. Monomer can be made into 5Ah ~ 1000 Ah (1 Ah = 1000m Ah), while the lead-acid battery 2V monomer is usually 100Ah ~ 150 Ah, the change range is small.
2. Light weight. The same capacity of solar LiFePo4 battery volume is 2/3 of the volume of lead-acid batteries, the weight is 1/3 of the latter.
3. Fast charging capability. Solar LiFePo4 battery charging current up to 1C, to achieve a large rate of charging; lead-acid battery current is generally required between 0.1C ~ 0.2C, can not reach fast charging performance.
4. Environmental protection. Lead-acid batteries exist in large quantities of heavy metals - lead, producing waste liquid, while solar LiFePo4 batteries do not contain any heavy metals, no pollution in the production and use.
5. High cost performance. Although lead-acid batteries due to its cheap materials, the acquisition cost is lower than the solar LiFePo4 batteries, but in the service life and routine maintenance of the economy is lower than the solar LiFePo4 batteries. Practical application results show that: solar lithium iron phosphate battery is more than four times the cost performance of lead-acid batteries.
Solar LiFePo4 battery applications are certainly mainly in the direction of energy storage, which is determined by the various advantages shown in the above comparison, if the energy density and discharge multiplier and other aspects and then do something to improve, lithium iron solar phosphate will become the family energy storage choice!