High-multiplying power lithium ion battery and preparation method thereof

Abstract

The invention discloses a high-multiplying power lithium ion battery and a preparation method thereof. The lithium ion battery comprises a cathode plate, an anode plate, a composite diaphragm and an electrolyte solution, and the surfaces of the diaphragm are coated with composite conductive layers; each composite conductive layer is composed of a bonding agent, a conductive agent and micropores; the cathode plate and the anode plate are each of a full-tab structure. The preparation method comprises the steps that the diaphragm coated with the composite conductive layers, the cathode plate and the anode plate are subjected to a winding process to prepare a wound core, and the wound core is subjected to the processes of packaging, baking, liquid injecting, hot-cold pressing, forming and capacity grading to prepare the high-multiplying power lithium ion battery. According to the high-multiplying power lithium ion battery and the preparation method thereof, by improving the characteristics of the interfaces between the diaphragm and cathode and anode membranes and optimizing the structural design of the battery, the bonding performance of the contact interfaces between the diaphragm and the cathode and anode plates is improved, the lithium ion transfer resistance between the different interfaces is decreased, the electronic conductivity of the cathode and anode plates is enhanced, the porosity and the air permeability of the composite diaphragm are improved, wetting of the electrolyte solution to the diaphragm is improved, the retaining capacity of the electrolyte solution in the battery is improved, the high-multiplying power performance of the lithium ion battery is greatly improved, the high-multiplying power discharge capacity retention rate is increased by 10% or above compared with the prior art, and the high-multiplying power lithium ion battery is suitable for industrialized production.

Description

Technical field [0001] The invention relates to a lithium-ion battery, in particular to a high-rate lithium-ion battery. The invention also relates to a method for manufacturing the high-rate lithium-ion battery, belonging to the technical field of lithium-ion battery preparation. Background technique [0002] Lithium-ion secondary batteries have now become the mainstream chemical power source and are widely used in most mobile terminal devices. Compared with nickel-hydrogen nickel-cadmium lead-acid batteries, they have the advantages of high working voltage, high specific energy and long cycle life. In recent years, with the rapid development of power tools, aircraft models, drones, etc., the application fields of unmanned equipment are also expanding. For example, agricultural drones spray pesticides on crops and unmanned ships monitor water quality. Applications demand higher and higher battery output power. For example, small model airplanes require continuous discharge at a ...

AI Technical Summary

Problems solved by technology

The internal resistance of the battery is mainly determined by the battery's internal current collector, active material, and the conductivity of the electrolyte. When the battery is discharged at a high rate, lithium ions are quickly released from the negative electrode active material and pass through the separator to undergo a lithium intercalation reaction with the positive electrode active material. In this process, the moving speed of lithium ions also determines the rate performance of the battery. In order to reduce the diffusion path of lithium ions, it is necessary to reduce the interface distance between both sides of the separator and the positive and negative electrodes as much as possible. The current commercial lithium Ion batteries usually coat a layer of polyvinylidene fluoride on the diaphragm as the adhesive between the diaphragm and the positive and negative electrodes. Since the porosity of the polyvinylidene fluoride film is relatively small, and the polyvinylidene fluoride layer is an insulator, This reduces the transmission of lithium ions on these two interfaces to a certain extent, which also reduces the high-current discharge performance of the battery.

At the same time, most of the current batteries adopt the structure of ultrasonic welding tabs, which cannot withstand high-current discharge.

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