In the field of solar-powered lights with battery backup in the past two years, lithium iron phosphate batteries have gradually become the new favorite of the market instead of traditional colloidal buried batteries. So what advantages does it have to replace colloidal batteries, and what are the disadvantages of lithium iron phosphate battery that users need to pay attention to in use?

Lithium ion battery fundamentals

Lithium battery mainly refers to a type of battery that uses lithium element as the main active material in the electrode material. Lithium batteries are divided into lithium primary batteries (primary batteries) and lithium secondary batteries.

Advantages of solar street light with lithium ion battery

Compared with NiMH batteries, lithium batteries have the following significant advantages:

High operating voltage, high lithium iron phosphate battery energy density, low self-discharge rate, and no memory effect, long solar battery lifespan. Lithium batteries can be made thinner (the thinnest polymer lithium battery is only 0.5mm), and smaller; the area and shape can be changed at will, this greatly improves the flexibility of battery design. Lithium phosphate battery manufacturers can make batteries of any shape and capacity according to the needs of users. Compared with lead-acid batteries, lithium batteries are light and durable and have relatively less environmental pollution. Lithium batteries are often charged and discharged, charging when it is not fully discharged, or using an external power supply, using it while charging, or continuing to use the external power supply after charging is complete, will not cause additional damage to the battery.

Disadvantages of lithium batteries

1. Lithium batteries are neither resistant to high temperature nor low temperature, so normally the LiFePO4 battery operating temperature range is not so wide. Besides, due to some defects in the manufacturing process, there is a possibility of explosion when the ambient temperature is high.
2. Vulnerable to overcharging. Long-term charging of battery packs for solar lights will keep the battery at the edge of danger for a long time because long-term charging will degrade the characteristics of the battery’s charge-discharge protection circuit. After the lithium battery has been charged for a certain period of time, if the charger is not removed, the system will not only stop charging, but will also start a discharge-charge cycle, and the life of the charger will decrease. Judging from the situation of some countries’ power grids, the voltage at night in many places is relatively high and fluctuates greatly. The lithium-ion battery is much less resistant to fluctuations in charge and discharge than nickel batteries, so the life of lithium batteries will be further reduced.
3. Due to the very active chemical properties of lithium metal, the processing, storage, use and environmental requirements of lithium metal are very high. Therefore, when not in use for a long time, the lithium battery should be taken out and placed in a cool and dry place. Do not freeze to avoid water vapor erosion.
4. Iron phosphate batteries &  lithium ion batteries are rarely used in large-scale energy storage and power batteries (which require a large current instantaneously). The main reason is that lithium batteries use lithium and cobalt as cathode materials, which are not resistant to high current, high voltage, high torque, impact, and high temperature. , low temperature and other special environments, and safety are not guaranteed.
5. Lithium-cobalt batteries cannot be charged quickly and completely avoid secondary pollution. A protection circuit must be designed to prevent overcharging or over-discharging, otherwise, it will cause dangers such as an explosion.
6. The price of cobalt is getting higher and higher. The largest producer of cobalt in the world, the Congo, has had many wars and turmoil, resulting in the rising price of cobalt.
7. Avoid buying spare lithium batteries for storage, because even if the battery is not used, its service life is naturally degraded.