Preparation method of ultrathin lithium metal negative electrode

Abstract

The invention discloses a preparation method of an ultrathin lithium metal negative electrode, and belongs to the technical field of lithium primary batteries. The thickness of ultrathin lithium metalis less than 100[mu]m; and the preparation method of the ultrathin lithium metal negative electrode is characterized by comprising the following steps: step 1, cutting an ultrathin lithium strip intoultrathin lithium sheets according to requirements; step 2, cutting a copper foil into tabs according to requirements; step 3, lithium sheet treatment: brushing a lithium sheet and tab bonding area with at least one of natural bristles, horse hairs, sisal hemp, soft plastic fibers, nylon, polypropylene, polyethylene and PBT to remove a lithium sheet passivation layer in the tab area; and step 4,negative electrode piece pressing: adhering a current collecting tab to the treated lithium sheet area, adopting plane pressing equipment and setting equipment pressure; wrapping the upper part and the lower part of the prepared negative electrode piece with polypropylene films respectively; and placing the negative electrode piece between an upper plate and a lower plate of a flat plate pressingmachine, and pressing to obtain the tightly combined negative electrode piece.

Description

technical field [0001] The invention belongs to the technical field of lithium primary batteries, and in particular relates to a preparation method of an ultra-thin lithium metal negative electrode. Background technique [0002] Because lithium primary batteries have excellent performance (such as high energy ratio, long service life, high rated voltage, low self-discharge rate, green environmental protection, etc.), they are widely used in cameras, watches, electronic security, storage backup power, notebook computers Backup power and military and other fields. Lithium is the negative electrode material with the smallest atomic weight, the highest electrochemical equivalent, and the lowest electrode potential among known metals. A battery composed of a suitable positive electrode material is currently the battery system with the highest specific energy. With the increasing application range of lithium primary batteries, various fields have put forward higher requirements f...

AI Technical Summary

Problems solved by technology

During the discharge process, it is possible that some segments of metal lithium will be consumed, causing the tabs to separate from the lithium sheet, increasing the contact internal resistance of the negative electrode interface or even breaking the circuit, causing the battery to fail to discharge normally in the later stage, and the discharge capacity to decrease.

This problem is especially common in the lamination process of ultra-thin lithium sheets and tabs. The main reason is that a passivation film is easily formed on the surface of lithium sheets with a thickness of less than 100 μm during the production process, which makes the contact with smooth copper foil It is difficult to press into a tightly bonded whole, resulting in weak adhesion of the tabs on the surface of the lithium sheet (see figure 2 ), the contact internal resistance becomes larger, which affects the power characteristics of the battery

[0004] In response to these problems, the conventional solution is to increase the pressing pressure, or to perforate or surface-treat the copper foil of the current collector to increase the roughness of the copper foil surface, but in the preparation process of the negative electrode of the power lithium primary battery, The effect of this method is not good, and the area of ​​the tab is very small, and the perforation will affect the current collection effect

Simply increasing the pressing pressure can not achieve the effect of tight pressing

A passivation film is easily formed on the surface of a lithium sheet with a thickness of less than 100 μm during the production process, making it difficult to press into a tightly bonded whole with the smooth copper foil, resulting in poor adhesion of tabs to the surface of the lithium sheet. The contact internal resistance becomes larger, which affects the power characteristics of the battery

In response to these problems, the conventional solution is to increase the pressing pressure, or to perforate or surface-treat the copper foil of the current collector to increase the roughness of the copper foil surface, but in the preparation process of the negative electrode of the power lithium primary battery, The effect of this method is not good, and the area of ​​the tab is very small, and the perforation will affect the current collection effect

Simply increasing the pressing pressure can not achieve the effect of tight pressing

Therefore, it is necessary to find an effective, simple and easy-to-operate method to solve the problem of insufficient bonding force between ultra-thin lithium sheets and tabs, and improve the power characteristics of lithium primary batteries

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