Coiled laminate square lithium-ion battery cell and preparation method thereof

Abstract

The invention relates to a coiled laminate square lithium-ion battery cell and a preparation method thereof. The coiled laminate square lithium-ion battery cell comprises a platelike coiling needle (3), wherein the coiling needle (3) is coiled with strip-shaped pole pieces; the pole piece comprises a strip-shaped basal layer the surface of which is coated with an electrode material; the pole piece is provided with a coating area for the electrode material and an isolation area (11) used for disconnecting the coating areas; the isolation area (11) is positioned on the pole piece coiled on the two side edges of the coiling needle (3); and the range of the isolation area (11) comprises the whole pole piece coiled on the two side edges of the coiling needle (3). The pole pieces at the corner pieces of the two end side surfaces (the two side edges of the coiling needle) of the coiled laminate square lithium-ion battery cell are easy to yield, thus preventing the electrode material on the pole piece from dropping off or generating cracks.

Description

technical field [0001] The invention relates to a lithium ion battery, in particular to an electric core of the lithium ion battery, in particular to a wound-type laminated square lithium ion electric core and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in many fields, especially mobile phones and electronics industries, because of their outstanding characteristics such as high working voltage, large specific energy, and small self-discharge. With the continuous development of lithium battery application technology, the automotive industry is gradually using lithium batteries to provide power. At present, the commonly used lithium-ion battery structures are mainly stacked and wound. Since there is no tension between the pole piece and the separator in the conventional positive and negative electrode stacking technology, the expansion of the pole piece will cause the battery to The core is greatly deformed, resulting in a...

AI Technical Summary

Problems solved by technology

At present, the commonly used lithium-ion battery structures are mainly stacked and wound. Since there is no tension between the pole piece and the separator in the conventional positive and negative electrode stacking technology, the expansion of the pole piece will cause the battery to The core is greatly deformed, resulting in a drum shell, and at the same time, the separator is easy to wrinkle, and lithium is easy to accumulate in the wrinkle, which affects battery performance (capacity becomes smaller, cycle times become lower, self-discharge becomes higher, etc.), and the lamination The production efficiency of lithium-ion batteries is much lower than that of wound lithium-ion batteries

[0003] At present, the battery core of the winding lithium-ion battery includes a winding needle, a positive electrode piece, a negative electrode piece, a separator, a positive electrode ear and a negative electrode ear. It is made on a needle, and the square lithium-ion battery made by this method is only suitable for the cell winding of a very thin (thickness not exceeding 10mm) square battery. For a thick battery with a large capacity, it is not only difficult to flatten , and during winding or flattening, because the radius of curvature is too small, the pole pieces at the corners of the two ends of the battery core (both sides of the winding needle) are not easy to yield, causing the electrode material on the pole pieces to fall off or produce cracks, thereby reducing the performance of the battery and increasing the safety hazard of the battery

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