Photovoltaic off-grid system composition
Photovoltaic modules, off-grid inverters (including photovoltaic chargers/inverters), energy storage batteries (lead-acid/colloid/lead carbon/ternary lithium/lithium iron phosphate, etc.), photovoltaic brackets, cables, and accessories Electric boxes, etc., are an important part of photovoltaic off-grid systems.
The biggest difference between photovoltaic off-grid systems and grid-connected systems is that grid-connected systems take investment income as the calculation premise, while off-grid systems take just-needed power supply as the basic demand, so they will have different emphasis when selecting components.
Why should photovoltaic off-grid systems be equipped with energy storage lithium iron phosphate batteries?
In the photovoltaic off-grid system, the energy storage lithium iron phosphate battery accounts for a large proportion, and the cost is similar to the solar module, but the life span is much shorter than that of the solar module. The task of the energy storage iron lithium battery is to store energy to ensure the stability of the system power. Ensure that the load uses electricity in cloudy and rainy days.
1. Photovoltaic power generation time and load power time are not necessarily synchronized. Photovoltaic off-grid systems, the input is components, used for power generation, and the output is connected to the load. Photovoltaic power is generated during the day, and only when there is sunlight, the power generation is usually highest at noon, but at noon, the demand for electricity is not high. Many households use off-grid power stations to use electricity at night. What about the electricity generated during the day? Store energy first. This power storage device is an energy storage lithium iron phosphate battery. Wait for peak electricity consumption, such as 7 or 8 o'clock in the evening, before releasing the electricity.
2. Photovoltaic power generation and load power are not necessarily the same. Photovoltaic power generation is affected by radiance and is not very stable, and the load is also not stable. Like air conditioners and refrigerators, the starting power is very large, and the normal operating power is less. The load will cause the system to be unstable and the voltage will fluctuate.
The energy storage battery is a power balance device. When the photovoltaic power is greater than the load power, the controller sends the excess energy to the battery pack for storage. When the photovoltaic power cannot meet the load needs, the controller sends the battery power to the load. .
3. The cost of off-grid system is high. The off-grid system consists of photovoltaic arrays, solar controllers, inverters, battery packs, loads, etc. Compared with the grid-connected system, there are more batteries, which account for 30-40% of the cost of the power generation system, which is almost the same as the components. Moreover, the service life of batteries is not long. Lead-acid batteries are generally 3-5 years, and lithium batteries are generally 8-10 years, and they need to be replaced afterwards.
The new type of energy storage lithium iron phosphate battery, as the energy storage device of the photovoltaic system, can increase the energy storage efficiency to 95%, which can greatly reduce the cost of solar power generation. Lithium batteries have 95% energy efficiency, while currently commonly used lead-acid batteries are only about 80%. Lithium batteries are lighter in weight and have a longer service life than lead-acid batteries. The number of charge and discharge can reach 1600 cycles, which means that they do not need to be replaced frequently.
At present, photovoltaic power storage is increasingly adopting lithium batteries with technological breakthroughs. The market share of ternary lithium/lithium iron phosphate batteries is gradually increasing in photovoltaic off-grid systems, which is a new application trend.
Summary: In recent years, the proportion of new installed capacity of lithium battery energy storage systems in various energy storage systems has gradually increased. According to the application status and battery characteristics of energy storage power stations at home and abroad, it is recommended that the battery type of energy storage power stations is mainly lithium iron phosphate batteries.
