Method for fabricating lithium-ion secondary battery

Abstract

PROBLEM TO BE SOLVED: To achieve further improvement in the reliability and durability by steadily welding the metal plate and the electrode of a polymer lithium ion secondary battery or the like. SOLUTION: The upper metal plate 7a and the lower metal plate 9a on the side of the positive electrode are respectively welded to the positive electrode side electrode 3 in a manner of interposing the positive electrode side electrode 3 from the upper and lower side respectively. The upper metal plate 7b and the lower metal plate 9b on the side of the negative electrode are respectively welded to the negative electrode side electrode 5 in a manner of interposing the negative electrode 5 from the upper and lower side, respectively. Thereby, the occurrence of welding failure during electric resistance welding is eliminated.

Description

[0001] The present invention is a divisional application of the Chinese patent application No. 01803391.1 and the title of the invention is "battery, its manufacturing method, method of manufacturing welded parts, and support". technical field [0002] The present invention relates to a battery having a structure of metal sheets welded to electrodes, a method of manufacturing a battery including a welding step, a method of manufacturing a weld, and a stand. Background technique [0003] Lithium ion secondary batteries have been used in recent years as a power source capable of charging and discharging included in mobile phones and portable electronic devices. In addition, batteries using solid non-liquefied electrolytes without the risk of liquid leakage are known, for example. Such lithium ion secondary batteries have various external shapes, and batteries generally used for notebook type or notepad type portable electronic devices and mobile phones are generally of a flat ...

AI Technical Summary

Problems solved by technology

First of all, the setting range of the oscillation intensity and amplitude time of ultrasonic welding is small, and it is difficult to maintain the best welding conditions

Secondly, it is difficult to stabilize the welding strength, and a certain rate of defective welding occurs in mass production processing for manufacturing a large number of products

Because, in ultrasonic welding, only very thin alloy layers are produced at the interface between electrode and metal sheet, due to the increased roughness on both surfaces, so that in many cases they are only in a weakly connected state on the surface , and it is difficult to achieve the electrical and mechanical firm welding required for this welding surface

In addition, a natural oxide film produced on the surface of a metal sheet made of aluminum or an aluminum-based alloy forms an obstacle, and becomes weaker due to weak welding by ultrasonic welding

And if the electrode and the metal sheet are weakly welded as described above, the resistance on their part becomes high, with the unfavorable consequence that the voltage transmitted from the secondary battery cell through the electrode and the metal sheet is reduced, or the current is limited

[0015] Third, ultrasonic welding equipment is more expensive than resistance welding equipment, and equipment costs for mass production become higher

Fourth, ultrasonic welding equipment is larger than resistance welding equipment and requires a larger workshop area

However, it inevitably results in components such as strong solder remaining on the electrodes or the metal pieces after welding, which disadvantageously results in the remaining components which may significantly reduce the durability of the connection portion between the electrodes and the metal pieces.

For example, during the use of the secondary battery, the remaining components may gradually corrode the electrode, which eventually leads to damage, peeling, etc.

In addition, because soldering will make the thin aluminum sheet that constitutes the positive electrode terminal become high temperature, and the temperature inside the battery will also become high, resulting in poor battery quality, so it is not preferable to use soldering method to weld the positive electrode terminal and the circuit board.

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