Ultrathin lithium ion battery current collector, ultrathin lithium ion battery and preparation method

Abstract

The invention provides an ultrathin lithium ion battery current collector. The current collector is a metal composite foil. The metal composite foil at least comprises an easy-tin-soldering layer made of an easy-tin-soldering material and a current collection conducting layer. The current collection conducting layer is one of an aluminum layer, an aluminum alloy layer, a titanium layer, a titanium alloy layer or a chromium layer. The easy-tin-soldering layer and the current collection conducting layer are combined into one. Because the metal composite foil comprises the easy-tin-soldering material and the current collection conducting layer, the metal composite foil can be employed as a packaging film of an ultrathin lithium ion battery, the easy-tin-soldering layer can perform supersonic wave point welding, laser point welding, alternating current point welding, direct current point welding or tin soldering, the welding modes are developed, the solderability is high, and the metal composite foil is convenient to use for users. When tin soldering is employed, welding of a connection sheet is not needed, operations are reduced, the qualified rate is high, and the labor cost is low. The invention also provides an ultrathin lithium ion battery using the ultrathin lithium ion battery current collector and a preparation method. The provided ultrathin lithium ion battery can solve the welding and cracking problems in the prior art effectively, and has good economic benefits.

Description

technical field [0001] The invention relates to the technical field of secondary batteries, in particular to an ultra-thin lithium-ion battery current collector, an ultra-thin lithium-ion battery and a manufacturing method thereof. Background technique [0002] An ultra-thin lithium-ion battery, such as the ultra-thin lithium-ion battery introduced in Chinese patent document CN202503073U, includes a positive electrode sheet, a negative electrode sheet, an electrolyte, a diaphragm and a hot-melt rubber ring. The diaphragm separates the positive electrode sheet from the negative electrode sheet, and the diaphragm and the negative electrode sheet Electrolyte is filled between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet consists of positive electrode current collector, positive electrode paste, and positive electrode tab. The positive electrode current collector is made of titanium foil or titanium alloy foil or chromium foil. The p...

AI Technical Summary

Problems solved by technology

[0005] 1. Welding problems: titanium foil, titanium alloy foil, and chromium foil can be spot welded, ultrasonic welded or laser welded, but not tin welded, which brings restrictions to users; it is necessary to spot weld or ultrasonic weld or laser weld nickel on the tab first Chips can only be soldered, resulting in more processes, lower pass rate, and increased labor costs

[0006] 2. Cracking problem: The scope of application of ultra-thin lithium-ion batteries made of titanium foil, titanium alloy foil, and chromium foil is limited, because some liquid electrolytes will corrode the titanium foil or titanium alloy foil or chromium foil and the hot-melt rubber ring Bonding interface, resulting in insufficient sealing durability, resulting in cracking of the bonding interface between titanium foil or titanium alloy foil or chrome foil and the hot melt rubber ring, resulting in battery failure, affecting storage life and service life; even if physical degreasing, chemical Treatments such as degreasing, ultrasonic degreasing, and chemical oxidation (passivation) still cannot solve the problem of cracking when using liquid electrolytes; titanium foil, titanium alloy foil, and chromium foil are more suitable for ultra-thin lithium-ion batteries with solid electrolytes or gel electrolytes. Batteries, ultra-thin lithium-ion batteries that cannot adapt to all liquid electrolytes

[0007] Chinese patent document CN1557029 introduces a flexible thin battery and its manufacturing method, mainly introduces the structure of the flexible thin battery, the first layer is an adhesive layer, the second layer is a protective layer, the third layer is a conductive layer, and the third layer sandwich Between the first and second layers; its impermeable metal foil layer can be any kind of metal, such as aluminum, nickel, copper, and stainless steel; presents a primary battery and does not involve charging

[0008] To sum up, the single-material current collector and packaging film used in the positive and negative electrodes of the existing ultra-thin lithium-ion batteries has defects such as poor weldability, low strength, low durability, and poor corrosion resistance that are difficult to take into account at the same time, which affects ultra-thin lithium-ion batteries. Production and Application of Lithium-ion Batteries

Images