Electrode plate and preparation method thereof, and lithium ion battery

Abstract

The invention provides an electrode plate and a preparation method thereof, and a lithium ion battery. The electrode plate comprises a current collector and active substance layers positioned on two sides of the current collector, wherein the active substance layers are provided with holes, and the thickness of the electrode plate is more than 0.30 mm. The preparation method comprises the following steps: 1) coating two surfaces of the current collector with electrode slurry, and carrying out drying and rolling to obtain an unpunched electrode plate, wherein the thickness of the electrode plate which is not punched is 0.30 mm or above; and 2) punching the active substance layers of the unpunched electrode plate to obtain the electrode plate. According to the electrode plate provided by theinvention, by increasing the thickness of the electrode plate, the proportion of the current collector is reduced, and specific energy is improved; the electronic conductivity of the electrode plateis improved through the variety and proportion of a conductive agent; by punching holes in the active substance layers, the liquid absorption property of the electrode plate is improved, the polarization internal resistance of the electrode plate is reduced, the optimization of the ionic conductance of the electrode plate is improved, and the rate capability of the battery is maintained.

Description

technical field [0001] The invention belongs to the technical field of batteries, and relates to an electrode pole piece, a preparation method thereof and a lithium ion battery. Background technique [0002] With the improvement of the energy density requirement of the battery, part of the power performance of the battery cell is sacrificed in the design. In order to make the battery cell have a high energy density and good power performance, the thickness of the current electrode pole piece of the lithium-ion battery is <0.2mm . However, this requires a larger area of ​​copper foil, aluminum foil and other heavy inactive materials in the design of the battery. This design reduces the battery's weight-to-energy ratio. [0003] Although CN106450433 proposes the use of mesh foil, which reduces the amount of copper foil and aluminum foil used, reduces the weight of the battery without changing its power performance, and improves the energy density of the battery; but it us...

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Problems solved by technology

[0003] Although CN106450433 proposes the use of mesh foil, which reduces the amount of copper foil and aluminum foil used, reduces the weight of the battery without changing its power performance, and improves the energy density of the battery; but it uses a mesh structure. Foil, so that it can only be used for the preparation of soft-packed batteries, the use of mesh foils in the production of industrialized large batteries will increase the cost of preparing batteries and there will be a risk of breaking the tape during the manufacturing process

[0004] CN208690386U proposes to improve the ionic and electronic conductivity of the pole piece by mechanically punching holes on the surface of the pole piece after rolling, and improve the rate performance of the battery, but it is limited to the promotion of the conductivity of the pole piece in the actual operation process

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