To date, the most popular type of chemical current sources (CPS) are still lead-acid batteries. Despite the huge leap in the development of lithium HEPS in recent years, if we add up all the energy stored in the world (Wh) in lead and lithium batteries, we will see that “lead” in this indicator is an order of magnitude ahead of Li-ion, LiFePO4 and LTO combined. The point, of course, is the low cost of lead-acid batteries.
There are applications where overpaying for better performance is simply not worth it, such as car starter batteries. The main task of such a battery is to deliver a large current for a short time, and such parameters as capacity, weight, resource, etc. recede into the background.
Progress does not stand still, and every year, thanks to the use of new materials and the use of innovative technologies, the production of lithium batteries is becoming cheaper, and at the same time, their scope is expanding significantly. There are many LiFePo4 battery manufacturer who are trying to make it cheaper and cheaper.
The main advantages of LiFePO4 compared to lead-acid batteries:
- The capacity is several times larger. LiFePO4 – 190–250 Wh/kg; lead-acid – 25-40 W•h/kg.
- They give full capacity at high discharge currents.
- Charged with 5 times more current compared to lead-acid batteries.
- Not sensitive to chronic undercharge modes.
- Lighter than lead acid.
- 10x more cycles than lead acid.
- Long service life.
Why LiFePO4 and not Li-ion or LTO?
LTO can be deleted immediately, the applications for this type of battery are very specific, since its cost is still very high.
The advantages of LiFePO4 over Li-ion are as follows:
- Temperature resistance. LiFePO4 can work at low temperatures – from -30°C to +55°C
- Lithium-iron-phosphate batteries have a large number of charge-discharge cycles (up to 2000 cycles) and, as a result, a long service life.
- Discharge voltage stability – LiFePO4 batteries supply the consumer with a constant voltage during discharge
- LiFePO4 batteries do not burn, with severe damage to the elements, heat and smoke are released, but, unlike lithium-ion batteries, there is no flame.
The main disadvantage of LiFePO4 over Li-ion is the lower capacity for the same weight – about 20% less, but still many times more than lead batteries.
Thanks to the combination of the above characteristics, lithium iron phosphate batteries have become an excellent alternative to lead-acid batteries.
Applications For LiFePo4
Until now, in many areas, lead batteries seemed to be the most cost-effective option. But due to declining costs, lithium iron phosphate batteries are replacing lead at a rapid pace in many places. Consider the main areas of application of LiFePO4.
Water Transport
There are 2 scenarios for using batteries in small boats:
- Battery to power the main electric motor on small boats.
- Battery for powering the on-board network and auxiliary electric motors on medium and large motor boats.
In the case of a small electric motor boat, the advantages lithium-iron-phosphate batteries are especially pronounced. The key factors are the low weight of the battery compared to lead. With LiFePO4, you can increase the range by several times, while maintaining adequate weight and dimensions of the battery.
Another important advantage is the ability to deeply discharge the battery without harm to it. In the case of lead batteries, at 25-30% charge level, you have to choose: Either stop using the motor, or continue discharging the battery, thereby exposing it to degradation.
Each deep discharge of a lead-acid battery takes away approximately 2-3% of its original capacity. It is easy to calculate that after 10 such discharges, the battery will lose up to 30% of its capacity.
On medium and large boats, the weight of the batteries is no longer so important, but the number of charge-discharge cycles and the possibility of deep discharge are the main parameters when choosing a battery. The fact is that many boats are equipped with special auxiliary electric motors. They help to keep the vessel at a given point, and also serve to move quietly without using the main internal combustion engine.
With the active use of a boat with such an auxiliary motor, the batteries are constantly being charged and discharged. Lead batteries with their 200 cycles are fundamentally not suitable for this task. Of course, the ideal solution is lithium titanate (LTO), such batteries can withstand a fantastic 20,000 cycles, but they are also expensive. Therefore, LiFePO4 with their 2000 cycles will be the best solution financially.
Loaders, Stackers, Scrubbers
The main parameter when choosing a battery for forklifts and stackers is the maximum long-term discharge current, since this technique consumes high currents during its operation. It is important that under load there are no significant voltage drops. LiFePO4 fully meets this requirement. Lithium-iron-phosphate batteries have minimal voltage drops, while this voltage remains stable throughout the entire discharge cycle and practically does not change.
The large resource of LiFePO4 also plays into the hands, since warehouse equipment, as a rule, works every day. The same can be said about scrubbers, often these devices work 24/7, and battery life is of paramount importance.
Electric Transport
Of course, in the world of electric vehicles, lithium-ion batteries are superior. Due to the record performance in terms of capacity to mass and volume ratio, this type of battery has become widely used in electric vehicles, electric bikes, electric bicycles, etc. But since Li-ion cannot work correctly at negative temperatures, this imposes certain restrictions. And if in electric vehicles this can be solved with the help of built-in battery heating, then in simpler types of electric transport one has to look for an alternative to lithium-ion batteries.
Lead and LiFePO4 batteries are suitable for this alternative, as they can easily withstand negative temperatures. Of course, LiFePO4 would be the best solution, since they are second in terms of capacity per unit weight and volume after Li-ion.
In general, we can say that lead-acid batteries are living out their last days. Increasingly, industries are switching to lithium iron phosphate and lithium titanate. The production of lithium batteries is getting cheaper every year, and the only advantage of lead batteries will soon come to naught – the price.
