How safe are LiFePO4 batteries?This question should be answered from three aspects: material/structural stability, production process, and charge-discharge characteristics.
are lifepo4 batteries safe？
1.The lithium iron phosphate batteries is the safest cathode material for lithium ion batteries at present. It does not contain any heavy metal elements that are harmful to the human body. The oxygen in the olivine structure is difficult to separate out, which improves the stability of the material.
2.The production process of lithium iron phosphate battery pack is roughly the same as that of other lithium battery types. The core processes are: batching, coating, rolling, filming, and winding. In the batching process, the conductivity of lithium iron phosphate materials is relatively poor, so the particles are generally made smaller. The objective effect of this is that the internal arrangement is more uniform, which promotes the formation of a balanced voltage platform, which can be maintained during operation. The state of the battery is stable.
3.Charging and discharging are the two basic working states of lithium battery packs. When the lithium iron phosphate battery pack is charged and discharged, due to the weak oxidizing ability of iron ions, it will not release oxygen, so it is naturally difficult to have a redox reaction with the electrolyte, which makes the charging and discharging process of the lithium iron phosphate battery in a safe environment. .
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Not only that, it is difficult for the lithium iron phosphate battery pack to undergo severe redox reactions during high-rate discharge, even during overcharge and discharge. At the same time, after the lithium is deintercalated, the lattice change will reduce the final volume of the unit cell, which just offsets the increased volume of the carbon negative electrode during the reaction. Therefore, the lithium iron phosphate battery pack can maintain the stability of the physical structure during charging and discharging. , which eliminates the hidden danger of battery explosion caused by the increase in volume.
The P-O bond in the lithium iron phosphate crystal is stable and difficult to decompose. Even at high temperature or overcharge, it will not collapse and generate heat like lithium cobalt oxide or form strong oxidizing substances, so lithium battery packs have good safety. There are reports that a small number of samples were found to be burning in acupuncture or short-circuit experiments in actual operation, but no explosion occurred.
Will lithium iron phosphate batteries explode?
Lithium battery generally do not explode. The safety of lithium iron phosphate battery is quite high in normal use. But nothing is absolute. In some extreme cases it can still be dangerous. This has a lot to do with the material selection, ratio, process and later use of each company.
Although the thermal stability and structural stability of lithium iron phosphate material are the highest among all cathode materials in terms of thermodynamics, and it has also been verified in the actual safety performance test, the possibility of short circuit from the material and the battery And by chance, it’s probably the least secure.
The performance characteristics of lithium iron phosphate battery pack
1. High-efficiency output: standard discharge is 2~5C, continuous high-current discharge can reach 10C, and instantaneous pulse discharge (10S) can reach 20C;
2.Good performance at high temperature: when the external temperature is 65 °C, the internal temperature is as high as 95 °C, and when the battery is discharged, the temperature can reach 160 °C, and the structure of the battery is safe and intact;
3.Even if the battery is damaged internally or externally, the battery does not burn, does not explode, and has the best safety;
4.Excellent cycle life, after 500 cycles, the discharge capacity is still greater than 95%;
5.It can be charged quickly, the battery can be fully charged within 40 minutes at 1.5C under a special charger, and the starting current can reach 2C;
6.No memory effect: no matter what state the lithium iron phosphate battery pack is in, it can be used at any time without having to discharge it before charging;
7.Small in size and light in weight, the volume of the lithium iron phosphate battery of the same specification and capacity is 1/3 of the volume of the lead-acid battery, and the weight is 1/3 of the lead-acid battery.
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In conclusion, Compared with other lithium batteries, the safety of lithium iron phosphate battery packs is the best. At the same time, the battery also has the characteristics of long service life, support for high current charging and discharging, and light weight.
The safety of lithium iron phosphate batteries is second to none among lithium batteries, and because of this, it has become one of the main categories of electric vehicle batteries. With the increasing requirements of domestic lithium battery manufacturers for battery performance, all manufacturers should actively improve the performance of lithium battery products, improve the discharge rate and safety performance.