Pole sheet lithium powder rolling device and method

Abstract

The invention belongs to the technical field of battery manufacturing, and particularly relates to a pole piece lithium powder rolling device. The pole piece lithium powder rolling device comprises an uncoiling mechanism, a coiling mechanism, a pressure roller mechanism and a wrap angle roller, wherein the pressure roller mechanism is arranged between the uncoiling mechanism and the coiling mechanism; the wrap angle roller is arranged between the uncoiling mechanism and the coiling mechanism; the pressure roller mechanism comprises an upper pressure roller and a lower pressure roller matched with the upper pressure roller; the uncoiling mechanism comprises an uncoiling roller; and an upper edge of the wrap angle roller is higher than a common tangent between an upper edge of the uncoiling roller and a lower edge of the upper pressure roller. The wrap angle roller can support a pole piece in order to increase a wrap angle of the pole piece specific to the upper pressure roller, namely, increase a contact area between the pole piece and the upper pressure roller and apply a pre-pressure to the pole piece, so that the upper pressure roller and the lower pressure roller with small roller diameters can be used, and a rolling effect can be ensured, thereby making the device become more compact. Moreover, after the contact area between the pole piece and the upper pressure roller is increased, the pole piece tends not to fold or crimp, thereby increasing the rolling speed of the pressure roller mechanism, and increasing the productivity. The invention also provides a pole piece lithium powder rolling method.

Description

technical field [0001] The invention belongs to the technical field of battery manufacturing, and in particular relates to a pole piece lithium powder rolling device and method. Background technique [0002] Lithium-ion batteries have become one of the most widely used secondary batteries due to their advantages of high voltage, high energy density and long cycle life. However, with the miniaturization of portable electronic devices and the continuous development of long standby time, as well as the use of high-power and high-energy devices such as electric bicycles and electric vehicles, the energy density of lithium-ion batteries as energy storage power sources has been increasingly raised. high demands. [0003] For the negative electrode sheet, part of the lithium will be consumed due to the formation of the solid electrolyte film (SEI film) during the first charging process of the battery, which will cause the loss of lithium in the positive electrode material, thereby...

AI Technical Summary

Problems solved by technology

When the lithium powder is compacted and applied to the negative electrode sheet of the lithium battery by rolling, the rolling effect of the rolling rolls used is different, and the rolling rolls with small roll diameters can be rolled more finely, but due to The contact area between it and the pole piece is small, so the line speed should not be too fast during rolling, otherwise it will easily cause the pole piece to wrinkle, but if the line speed is too slow, it will affect the production capacity

In order to increase the contact area between the pressure roller and the pole piece, the diameter of the pressure roller is enlarged to form a large wrap angle structure, but the pressure roller with a large diameter will make the whole device bulky, increase the equipment cost, and make the equipment become not compact enough

In addition, since metal lithium powder is relatively soft, direct rolling will cause lithium powder to stick to the roller. Therefore, the above three Chinese patent application documents all use protective film to isolate rolling, and the protective film is disposable, and it is necessary to add an additional layer for the protective film Unwinding mechanism

Although it solves the problem of roller sticking, it also increases the cost and brings burden to the enterprise

Images