Cathode paste of rapidly discharged/charged high power lithium ion battery and manufacturing method thereof

Abstract

The invention discloses a cathode paste of a rapidly discharged / charged high power lithium ion battery. The cathode paste comprises following components in parts by weight: 55 to 75 parts of active substance C, 20.5 to 36 parts of active substance D, 1 to 2 parts of thickening agent, 2 to 4 parts of conductive agent C, and 1.5 to 3 parts of binder B; wherein the active substance C is artificial graphite or meso-phase carbon micro beads; the active substance D is soft carbon or hard carbon; the conductive agent C is Super-P; the thickening agent is sodium carboxymethyl cellulose CMC; and the binder B is styrene butadiene rubber SBR or polystyrene-acrylate. The provided lithium ion battery can be rapidly charged and discharged, has high power and a long service life, and can be continuouslydischarged or charged (30C). The 30C constant current charge capacity can account for 70% or more of 1C capacity, and the 30C discharge capacity can account for 90% or more of 1C capacity. Compared with a conventional power type lithium ion battery, the charge performance is improved by 20% or more, and the discharge performance is improved by 10% or more.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery preparation, and relates to a negative electrode paste and a preparation method of a fast-charging and fast-discharging high-power lithium-ion battery. 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 su...

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