FAQs
Frequently Asked Question
The lithium iron phosphate (LiFePO4) battery is a type of rechargeable battery, specifically a lithium ion battery, which uses LiFePO4 as a cathode material.
There are three types of Lithium Ion Cells based on different cathode materials. They are lithium cobalt oxide, lithium manganese oxide and lithium iron phosphate types. Although lithium cobalt oxide cell has the advantage of high energy density, it suffers from safety concerns. Lithium manganese oxide cell has been evaluated for the application on high rate due to the better safety characteristics. However, its high temperature performance is the major drawback. While Lithium iron phosphate cell has the best safety characteristics, long cycle life (+2000 cycles) and good availability. It has higher discharge current, but it has lower voltage and energy density than normal Li-ion cells. It is the safest and most suitable for high output usage. It is also the best for storage battery usage. It is not necessary to use the equalizer and the protecting PC Board module. Comparison Data among Various Lithium Base Batteries:
Battery | LiFePO4 | LiCoO2 | LiMn2O4 | Li(NiCo)O2 |
Safety | Safest | Not Stable | Acceptable | Not Stable |
Environmental concern | Most Enviro-friendly | Dangerous | Friendly | Very Dangerous |
Cycle life | Best/Excellent | Acceptable | Acceptable | Acceptable |
Power/Weight Density | Acceptable | Good | Acceptable | Best |
Long Term Cost | Most Economic/Excellent | High | Acceptable | High |
Temperature Range | Excellent (-20C to 75C) | Decay beyond (-20C to 55C) | Decay extremely fast over 50 C | -20C to 55C |
In summary, the characteristics of lithium iron phosphate (LiFePO4) are as follows:
A) The safest and the most environmentally friendly
The Lithium Iron Phosphate Battery has been proven as the most environmentally friendly battery. The primary concern with Li-Ion batteries is safety. Overcharging and overheating can cause fire and explosions. The exception to this is the LiFePO4 battery.
B) Fast “forced” charging
Because an overvoltage can be applied to the LiFePO4 battery it can be charged by only one step of CC (Constant Current) to reach 95% SOC (State of Charge) or be charged by CC+CV (Constant Current + Constant Voltage) to get 100% SOC. This is similar to the way lead acid batteries are safely force charged.
C) Large overcharge tolerance and safer performance
A LiFePO4 battery can be safely overcharged up to 30V without protection circuit board. It is therefore suitable for large capacity and high-power applications. From the viewpoint of large overcharge tolerance and safety performance, a LiFePO4 battery is similar to a lead-acid battery.
D) Higher energy density
The lithium iron phosphate (LiFePO4) cell is a non-aqueous system, having 3.2V as its nominal voltage during discharge. Its specific capacity is more than 145Ah/kg. Therefore, the gravimetric energy density of LiFePO4 battery is 130Wh/kg,
E) Simplified battery management system and battery charger
Large overcharge tolerance and self-balance characteristic of LiFePO4 battery can simplify the battery protection and balance circuit boards, lowering their cost.
F) Longer cycle life
In comparison with LiCoO2 battery which has a cycle life of 500-800 cycles, LiFePO4 battery extends its cycle life ranges 2000-5000 cycles.
G) High temperature performance
It is detrimental to have a LiCoO2 battery working at elevated temperature, such as 60°C. However, a LiFePO4 battery runs better at elevated temperature, offering 10% more capacity, due to higher lithium ionic conductivity.
H) What are the main applications of the lithium iron phosphate (LiFePO4)?
Due to the characteristics of lithium iron phosphate (LiFePO4), it is very suitable for high discharge rate occasions such as Solar Energy System, Emergency Lighting, UPS, power tools (for example, electric drill, electric motor saw, cropper) and EVs (Electric Vehicles). According to different applications, the design of battery pack can be modified to provide the best solution to satisfy the customer’s needs.
When batteries connect in parallels or series, first the 2 batteries or more, have to be in same SOC, (state of charge), the second, battery BMS max volts tolerance value has to be higher than the total battery pack. The third, the total battery bank max charge and discharge current should be less than single pack. The fourth, BMS has to have the functions like balancing. Prishda Energy batteries can be connected in Series/Parallel up to 4, however when connecting in series/parallel the batteries need to be in same SOC.
Our LiFePO4 batteries are sealed. They can be put into locations that might get wet or damp without worry about damaging the battery.
Our LiFePO4 Lithium batteries are sealed, they do not release any liquids or harsh fumes.
Internal Features:
- Low Voltage Protection Switch – Automatically disconnects at 8V
- Over Voltage Protection Switch – Automatically disconnects at 15.6V
- Short Circuit Protection Switch – Automatically disconnects
- Reverse Polarity Protection Switch – Automatically disconnects
- Internal cell balancing – Automatically balances cells
- Charge Balancing – Independent balancing for multiple batteries connected in parallel or in series.
For a more accurate calculation of battery currents divide load watts by actual battery voltage, this will be in the range 12-14V (24-28V).
Then to allow for inverter efficiency, typically 85%, divide the figure by 0.85. Thus:
For a 300W load at 12V….300 ÷ 12 ÷ 0.85 = 29.4 Amps.
For a 300W load at 14V….300 ÷ 14 ÷ 0.85 = 25.2 Amps.
Similarly:
For a 300W load at 24V….300 ÷ 24 ÷ 0.85 = 14.7 Amps.
For a 300W load at 28V….300 ÷ 28 ÷ 0.85 = 12.6 Amps.
Note: Figures in brackets are for 24V systems.
