The safety issues that should be paid attention during production of lithium-ion battery

Lithium-ion is used in cardiac pacemaker at the earliest. The self-discharge rate of lithium-ion battery is very low, and the voltage of discharging is also flat. That's why cardiac pacemaker can work for a long time without charging. Generally speaking, lithium-ion battery has standard voltage over 3.0V, which is more suitable for integrated circuit power supply. Manganese dioxide battery is widely used in calculators, digital camera, and watch.

In order to develop more excellent performance of varieties, people of various materials were studied. To create an unprecedented product. For example, lithium sulfur dioxide battery and lithium thionyl chloride battery is very characteristic. Their positive active material and electrolyte solvent. This structure only in non-aqueous solution of electrochemical system. So, lithium-ion electricity pool research, also promoted the development of non-aqueous system electrochemical theory. In addition to use a variety of nonaqueous solvents, people also has carried on the research of polymer film battery.

Sony in 1992 successfully developed lithium-ion batteries. Its practical application, make people's mobile phone, notebook, calculator carry type electronic equipment such as less weight and volume. Use time greatly extended. Because do not contain heavy metal cadmium in lithium ion batteries, compared with the nickel cadmium battery, greatly reduce the pollution to the environment.

The safety problems in the process of lithium-ion battery production

Had better use the high viscosity adhesive glue, and make sure the adhesive is fully dissolved and adhesive is fully dry, water content control of NMP, when dissolved adhesive, best can heat, dissolving, more fully enhance adhesive bonding effect. If interested in water system of adhesive, can consider to Chengdu Yin le (LA132), if use water-based adhesive, bonding problem doesn't exist, but the vacuum baking temperature and time need to be extended appropriately.

To ensure that the lithium iron phosphate material and conductive material drying, had better be in 100-120 degree within the vacuum oven bake more than 2 hours, and down to room temperature, add in more PVDF solution.

Pay attention to ingredients workshop humidity, due to the reason of the circulating water, humidity is more difficult to control, thus recommended charging time as far as possible control in a relatively short period of time, and it is best to control the humidity below 30% RH.

Slurry agitation strength, it is better to use high energy shear emulsifying dispersion, or colloid mill, ensure fully dispersed and paste viscosity and liquidity, the viscosity of the slurry best adjustment in 5000-6000. Second, liquidity is a pulp can glue good premise, slurry liquidity much affected by the moisture, if the pulp a jellylike (into gel), on the performance of PVDF decline, generally difficult to do processing, so strong moisture control is very important in the process of mixing.

Due to material lithium iron phosphate coating speed is slow, when slurry coating may have some changes, especially when the humidity is bigger, affect material bonding effect, therefore, paste in relatively airtight container for the best good or partial transfer material.

Pole piece after coating and drying, the best production, if need to deposit a period of time in production, the best vacuum baking preserved. After the completion of the production, baking temperature should be set at 100 degrees, vacuum bake for about 10 h, not too long, too long to chip.

Winding or fold were most in need of attention is the control of the dust, especially on electrode bonding effect is not ideal, need more attention, otherwise it is easy to produce low voltage problem. Coiling should also pay attention to the battery assembly than batteries, the best control under 91%, otherwise, the assembly is bigger than too easy to cause the battery low voltage.

Battery baking suggested above 85 degrees bake for 24 hours, if using single-layer PE membrane, can be appropriate to reduce the temperature, but time must be guaranteed, and regularly take a breath.

Battery liquid injection rate control in 4 g/Ah, liquid injection should be put on hold after 7 hours, it is better to high temperature (50 degrees) on aging.

Into, it is best can use 0.05 c ratio charging 2 hours, 0.1 c charging five hours, 0.2 c constant current constant voltage charging more than 4 hours, on-line voltage at around 3.8 v (into voltage can be relatively a bit higher for the first time), 0.2 c discharge to 2.3 v.

Points when, had better use 0.2 c inflation (in order to improve the efficiency is also can use 0.5 c or 1 c put charging, charging and discharging voltage controlled between 3.8 v to 3.8 v.

If it shows a bottom of battery capacity or low voltage platform, it can be considered to use high temperature activation (65 ° c more than two hours) And then do the second time filling (0.1 c charging/discharging by small current), then conducts regular points again.

If there are a lot of batteries voltage is low, it can be considered to use large current to activate the battery. It can relieve the situation of low voltage.

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