Three-electrode soft package battery and preparation method thereof

Abstract

The invention discloses a three-electrode soft package battery and a preparation method thereof. The three-electrode soft package battery comprises a laminated battery packaged between an upper aluminum-plastic film and a lower aluminum-plastic film, wherein the laminated battery comprises a positive coated pole piece, two diaphragm layers and a negative coated pole piece; the positive coated pole piece is welded with a positive aluminum tab through a current collector; the negative coated pole piece is welded with a negative nickel tab through the current collector; a copper net is arranged between the two diaphragm layers; a lithium sheet metal covers the surface of one end of the copper net; the other end of the copper net extends out of the diaphragms and is connected with an auxiliary aluminum tab. According to a reference electrode preparation method adopted in the invention, lithium can be directly introduced into the battery, a general lithium plating process is omitted, the operation is easy, and the battery can be applicable to the reference electrode preparation process of various total batteries.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a three-electrode pouch battery and a preparation method thereof. Background technique [0002] When the traditional electrochemical workstation analyzes the internal mechanism of the battery, two electrodes are usually used for testing. The impedance spectrum test obtained in this way can only measure the entire impedance of the battery, and the positive and negative electrodes of the battery cannot be separated to study their respective effects on the internal resistance of the battery. contribution. Therefore, it is necessary to use three electrodes to distinguish the influence of the positive and negative materials in the battery on the impedance of the battery system. The three-electrode system has three electrodes: a working electrode (research electrode), a reference electrode, and an auxiliary electrode. Due to the measurement and monitoring ...

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Problems solved by technology

However, lithium is sensitive to oxygen and moisture and cannot be exposed to air

At present, in the research on the reference electrode of lithium batteries, there are direct purchase of lithium metal wires or lithium metal sheets placed between diaphragms as reference electrodes (Journal of Electroanalytical Chemistry 759 (2015) 91–94; Journal of Power Sources 111 (2002 ) 255–267), although this method is simple to operate, when the pure lithium metal wire / sheet is placed in the electrolyte as a reference electrode, lithium metal consumption or even dissolution may occur during long-term charge and discharge; and The reference electrode has only lithium and no other supporting metals are easily disconnected, making it difficult to continue the experiment as a reference electrode

There is also a research group that puts the copper wire in the middle of the separator, packs the battery and then performs lithium plating on the copper wire, so that a layer of lithium metal is attached to the copper surface (Journal of Power Sources 237 (2013) 285-290). The first method has also been tried, but its disadvantage is that it is difficult to maintain a long-term charge-discharge cycle. The layer of lithium plated is still relatively thin, and it will be exhausted after long-term charge-discharge.

If the lithium plating time is extended, problems such as lithium dendrites will appear

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