公開日:2022/04/27 / 最終更新日:2022/04/27

As a rechargeable battery necessities are: high capacity, excessive output voltage, good cost and discharge cycle efficiency, stable output voltage, high current cost and discharge, electrochemical stability, safety in use (not due to overcharge, over discharge and brief circuit and different improper operation brought on by combustion or explosion), huge operating temperature vary, non-toxic or much less toxic, no pollution to the surroundings.

Lithium iron phosphate ion battery utilizing LiFepO4 as the positive electrode in these efficiency necessities are good, particularly in the big discharge charge discharge (5 ~ 10C discharge), clean discharge voltage, safety (no combustion, no explosion), life (variety of cycles), no pollution to the environment, it’s the perfect, is the most effective excessive-current output energy lithium battery.

Structure and working precept

LiFepO4 is used as the constructive electrode of the battery, which is related by aluminum foil and the optimistic electrode of the battery. Within the center is the polymer diaphragm, which separates the constructive electrode from the unfavourable electrode, but lithium ion Li can go via however electron e- can’t, and on the appropriate is the detrimental electrode of the battery, which is composed of carbon (graphite) and linked by copper foil and the adverse electrode of the battery. Between the upper and decrease ends of the battery is the electrolyte of the battery, and the battery is hermetically sealed by a metallic shell.

LiFepO4 battery during charging, the lithium ion Li in the positive electrode migrates to the unfavourable electrode by way of the polymer diaphragm; throughout discharging, the lithium ion Li within the unfavorable electrode migrates to the optimistic electrode by the diaphragm. Li-ion batteries are named after the lithium ions that migrate again and forth during charging and discharging.

Important Properties

LiFepO4 batteries have a nominal voltage of 3.2 V, an end charge voltage of 3.6 V, and an end discharge voltage of 2.Zero V. There are some differences in efficiency as a result of the quality and means of the optimistic and damaging electrode materials and electrolyte materials used by every producer. For example, the same mannequin (commonplace battery in the identical package deal) has a large distinction (10% to 20%) within the capability of the battery.

It should be famous right here that completely different factories produce lithium iron phosphate energy lithium battery in the varied efficiency parameters will have some variations; in addition, there are some battery efficiency just isn’t included, corresponding to battery resistance, self-discharge rate, charging and discharging temperature, and so on..

Lithium iron phosphate power lithium battery capability has a big distinction, may be divided into three classes: small zero point a couple of to some mAh, medium-sized tens of mAh, massive a whole bunch of mAh. Related parameters of various kinds of batteries even have some differences.

Advantages

1, the safety performance of the improvement of lithium iron phosphate crystal in the p-O bond solid, tough to decompose, even at excessive temperatures or overcharge won’t be the identical as lithium cobalt construction collapse heat or the formation of strong oxidizing substances, and due to this fact has a good safety.

2, life improvement lithium-iron phosphate ion battery is the lithium-ion battery with lithium iron phosphate as the cathode materials. Long-life lead-acid battery cycle life of about 300 times, as much as 500 occasions, and lithium iron phosphate energy lithium batteries, cycle life of greater than 2000 occasions, the usual charge (5-hour charge) use, can reach 2000 instances.

3, high-temperature efficiency of lithium iron phosphate electric peak of 350 ℃ -500 ℃ and lithium manganate and lithium cobalt acid only in about 200 ℃.

4, high-capacity ∩ rechargeable batteries in usually in the full not put out underneath the conditions of labor, the capacity will quickly fall under the rated capacity value, this phenomenon is known as the memory effect. Like nickel-metallic hydride, nickel-cadmium batteries have memory, while lithium iron phosphate ion batteries with out this phenomenon, it doesn’t matter what state the battery is in, can be used as it’s charged, no have to first put out and then charged.

5, gentle weight, the identical capability of lithium iron phosphate battery volume is 2/3 of the amount of lead-acid batteries, the weight of lead-acid batteries 1 / 3.

6, environmental safety

Lithium iron phosphate ion batteries are generally considered to be freed from any heavy metals and uncommon metals (NiMH batteries require rare metals), non-toxic (SGS certification by), non-polluting, in step with European RoHS rules, for absolutely the green battery certificate.

Lithium iron phosphate also has basic defects that can not be ignored, which boils right down to the following vital points:

1, within the preparation of lithium iron phosphate sintering process, iron oxide in a excessive-temperature decreasing ambiance there is the opportunity of being diminished to singlet iron. Monolithic iron will cause a micro-quick circuit in the battery, is essentially the most taboo substance in the battery.

2, lithium iron phosphate has some performance defects, comparable to vibration density and compaction density could be very low, leading to a low energy density of lithium-ion batteries. Poor low-temperature efficiency, even whether it is nanosized and carbon cladding does not solve this downside.

3, the material preparation cost and the manufacturing value of the battery is excessive, the battery yield is low, and the consistency is poor. Nanosized lithium iron phosphate and carbon cladding, regardless of the improved electrochemical efficiency of the material, but in addition brings other problems, such because the discount of power density, increased synthesis prices, poor electrode processing efficiency and harsh environmental necessities.

Although the chemical elements Li, Fe and p in lithium iron phosphate is plentiful and low cost, however the preparation of lithium iron phosphate product cost will not be low, even if you take away the preliminary analysis and growth costs, the material course of value plus the higher value of making ready the battery, will make the final unit of energy storage energy value is higher.

In view of the above-mentioned issues of lithium iron phosphate, it’s tough to be widely used as the cathode materials for energy-type lithium-ion batteries in new energy automobiles and other fields. If the problems of high temperature cycling and poor storage performance of lithium manganate could be solved, there will probably be great potential for its software in energy-type lithium-ion batteries with its advantages of low value and excessive multiplier performance.