A fast-charging and fast-discharging high-power lithium-ion battery and its production method

Abstract

The invention discloses a fast-charging and fast-discharging high-power lithium-ion battery and a manufacturing method. The positive and negative current collectors respectively include aluminum foil and conductive coating, copper foil and conductive coating; the separator is made of bidirectional synchronously stretched PE material. The surface is coated with ceramic oxide; the positive electrode paste includes 10-35 lithium cobalt oxide, lithium nickel oxide, lithium manganate, lithium iron phosphate, lithium manganese phosphate, lithium iron manganese phosphate or lithium vanadium phosphate, 62-81 nickel cobalt manganate Lithium, 1‑3 Ketjen Black or carbon nanotubes, 1‑3 graphene or Super‑P and 1‑3 modified polyvinylidene fluoride; negative electrode paste includes 55‑75 artificial graphite or mesophase carbon microspheres, 20.5-36 soft or hard carbon, 1-2CMC, 2-4 Super-P and 1.5-3 styrene-butadiene rubber SBR or polystyrene-acrylate. The invention can meet the requirement of continuous charging and discharging at 30C, the 30C constant current charging capacity ratio can reach more than 70% of the 1C capacity, and the 30C discharge ratio can reach more than 90% of the 1C capacity.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery preparation, and relates to a fast-charging and fast-discharging lithium-ion battery and a manufacturing method thereof. Background technique [0002] Lithium-ion secondary battery has now become the mainstream chemical power source, and is widely used in most mobile terminal equipment and new energy vehicles. Long life and other advantages. In recent years, with the rapid development of electric tools, unmanned aerial vehicles, aircraft models, and new energy vehicles, especially with the batch application of lithium-ion batteries in HEV hybrid vehicles and 12V / 48V vehicle start-stop systems, lithium-ion secondary The charging and discharging power requirements of the battery are getting higher and higher, and generally need to meet the 30-40C rate charging and discharging requirements, but it is difficult for commercial lithium-ion batteries to meet such high-power charging and disc...

AI Technical Summary

Problems solved by technology

In recent years, with the rapid development of electric tools, unmanned aerial vehicles, aircraft models, and new energy vehicles, especially with the batch application of lithium-ion batteries in HEV hybrid vehicles and 12V / 48V vehicle start-stop systems, lithium-ion secondary The charging and discharging power requirements of the battery are getting higher and higher, and generally need to meet the 30-40C rate charging and discharging requirements, but it is difficult for commercial lithium-ion batteries to meet such high-power charging and discharging requirements.

[0003] The vehicle-mounted power lithium-ion battery needs to face three basic requirements: first, long life, the warranty period is generally required to be 5-8 years or 80,000-100,000 kilometers, but the lithium-ion battery is in the cycle of charging and discharging. The polarization of the battery will continue to increase, causing the battery life to not meet the usage requirements

The second is high power, but the lithium-ion battery will increase the polarization of the battery under the condition of high current charging and discharging, and the battery will generate serious heat, which will increase the side reaction, and then cause the battery capacity to decay, resulting in the power of the battery not meeting the use requirements.

The third is a wide temperature range, which needs to meet the requirements of the working range of -20°C-60°C, but the polarization of lithium-ion batteries will increase significantly under low temperature conditions, resulting in lithium deposition and capacity attenuation, so that it cannot be used under low temperature conditions. use

Traditional power lithium-ion batteries are relatively easy to meet high-rate continuous or pulse discharge, but under high-rate continuous charging or pulse charging, lithium-ion batteries are prone to lithium deposition, resulting in irreversible capacity loss of the battery, and even local lithium dendrites produce internal short circuits and cause This leads to thermal runaway of the battery, especially at low temperatures