What is the influence of environment when using lithium battery?

Along with the constant advocate for energy conservation and environmental protection in our country, more and more energy conservation and environmental protection device is developed. In battery market, whether it's dynamic type lithium battery or storage battery, have gradually been replaced by lithium-ion battery. Compared with traditional lead-acid batteries, lithium-ion batteries are with high charge and discharge frequency (1000 times, common battery 300 times), no memory effect, can be completely discharge, long service life, energy conservation, environmental protection, light weight (about a third of the lead-acid battery) etc. Even it costs higher than conventional lead-acid batteries, but it is made up by its long service life.

Lithium ion batteries the use of the environment is also very important influence on its cycle life. Among them, the environment temperature is important factors. Ambient temperature too low or too high will affect the cycle life of lithium batteries.

Small make up C/LiCoO2 is lithium ion battery was studied in 20 ℃ under the condition of charge and discharge performance. The result shows: the battery discharge performance at low temperature, 0.2 C discharge capacity is only 77% of the normal capacity, 1 C discharge capacity was only 0.2 C discharge capacity of 4%. Low temperature constant voltage charging time increases, the charging performance also significantly worse.

Lithium ion battery at low temperatures down the main reason for reducing the number of electric capacity, including: the electrolyte conductivity variation, the wetting of the diaphragm and/or permeability variation, lithium ion migration speed is slow, the electrode/electrolyte interface on the charge transfer rate slows, etc. In addition, the impedance of the SEI film at low temperature increases, the lithium ions through the electrode/electrolyte interface speed slow. Increases in the cost of the impedance of the SEI film is: lithium ion from the cathode at low temperatures out easy, embedded is difficult. Rechargeable lithium metal will appear and react with the electrolyte, form the new SEI film cover in the original on the SEI film, make the impedance of the battery increases leading to battery capacity decline.

The same batch of lithium-ion batteries at 60 ℃ and room temperature respectively 300 times charging and discharging cycle experiments. The initial stage, 60 ℃ under the condition of battery showed higher discharge capacity. But as the cycle of battery capacity attenuation speed and cycle stability is reduced, ballooning occurs late even have batteries. Under the high temperature lithium ion battery charge and discharge cycle is not stable, high temperature led to increasing battery electrode electrochemical polarization and gas production, ballooning phenomenon, the charge transfer resistance increases at the same time, ion transport dynamics performance degradation.

Most current lithium ion battery with LiPF6 as electrolyte, due to the impure or trace water electrolyte catalytic decomposition, conductive salt electrolyte containing HF acid. HF will with the main ingredient in SEI ROLi, the reaction of ROCO2Li etc., which generate LiF deposition in the cathode surface. SEI film containing LiF can hinder lithium ion migration. At the same time, the high impedance material may isolate insulation between graphite particles. Along with the high temperature of the charge and discharge, the cathode performance will worsen * eventually lead to battery failure.

In the condition of transportation or normal working of equipment with lithium-ion battery, it may stand the test of vibration, impact, collision etc. Some lithium-ion batteries will charge and discharge and receive data according to a certain frequency during system communication. Equipment vibration frequency may disturb battery frequency, and causing chip data error or trigger a protection circuit action. Under the strong vibration or shock, lithium-ion battery pole ear, external connection, terminal, solder joints, etc. may break or fall off. The battery pole piece active material may also peel, this will affect the service life of battery or even dangerous situations.

The page contains the contents of the machine translation.