Lithium ion battery negative electrode aqueous adhesive and preparation method thereof

Abstract

The invention relates to a lithium ion battery negative electrode aqueous adhesive and a preparation method thereof, and belongs to the field of energy storage device (battery eg.) manufacturing. The lithium ion battery aqueous adhesive comprises polymer emulsion, which comprises a hydrophilic unit, a hydrophobic unit, and an enhancing unit; wherein the hydrophilic unit comprises sulfonic acid groups accounting for 3.0 to 4.0 wt% of the polymer, and the glass-transition temperature of the polymer is -25 to 5 DEG C. Water is taken as the disperse medium, the adhesive is environmentally friendly, the bonding force of the adhesive is strong, and the using amount of the adhesive for negative electrodes can be reduced. The using amount of the adhesive is only 40% of SBR, the using requirements of battery preparation can be satisfied, and the discharging performance is better at a low temperature (-20 DEG C).

Description

technical field [0001] The invention relates to a lithium ion battery negative electrode material binder and a preparation method thereof, and belongs to the field of manufacturing energy storage devices such as batteries. Background technique [0002] Lithium-ion battery is the most ideal mobile power source, which has incomparable advantages of other batteries: high energy density, long life, small size, and no pollution. Lithium-ion batteries are widely used in electric vehicles, aerospace, communication equipment and various portable appliances. [0003] Lithium-ion batteries are mainly composed of positive electrodes, negative electrodes, separators and non-aqueous electrolytes; positive and negative electrodes are made of powdery electroactive materials, namely lithium transition metal oxide positive electrode materials and carbon negative electrode materials, binders, conductive Agent and current collector composition. It is made by mixing and grinding the electroac...

AI Technical Summary

Problems solved by technology

[0004] The binder that uses fluorine-containing olefin polymer solution as the negative electrode material of lithium-ion batteries has two obvious disadvantages: 1. The volatilization of the solvent in the electrode production process is easy to pollute the environment and have a greater impact on the health of the operators. Great harm; 2. The solvent price of fluorine-containing olefin polymer is high and the consumption is large, but special refrigeration equipment is needed to recover the solvent and process it, resulting in high production cost of the negative electrode

However, there are following disadvantages in use: 1. Negative electrode coating and drying need to be carried out at a lower temperature, resulting in low production efficiency of the pole piece, which cannot meet the high-efficiency negative pole production requirements; The pole piece is easy to break during the production process, and the edge is easy to drop when cutting the piece, which cannot meet the high-efficiency battery winding production process requirements; 3. LA132 adhesive is a resin material with a high glass transition temperature (Tg). The battery is prone to warping during the battery formation process, resulting in battery waste, reducing the yield of battery production, and increasing battery production costs

So far, the amount of negative electrode binder used is still relatively large, and the adhesiveness of the binder needs to be further improved

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