Sealed rechargeable battery and manufacturing method of the same

Abstract

The present invention relates to a sealed secondary battery, wherein an electrode group and an electrolyte are accommodated in a battery container composed of a metal bottom case and a sealing plate, wherein the electrode group is composed of a positive electrode material attached to a positive electrode current collector. The positive electrode plate and the negative electrode plate in which the negative electrode material is attached to the negative electrode current collector are wound by being separated by a diaphragm. The sealing plate is composed of a metal filter that constitutes an internal terminal, a safety mechanism that blocks the current path and discharges gas to the outside when the battery internal pressure is abnormal due to overcharging, etc., and a resin lining is stacked and accommodated The gasket and the metal cap terminal constituting the external terminal are sealed by caulking and sealing the peripheral portion of the metal filter so as to sandwich the resin inner gasket. Since the metal filter mesh and all the metal members housed in the metal filter mesh are joined by welding, it is possible to obtain a sealed secondary battery which has a sealing plate with a small impedance and requires high output power and large current discharge. .

Description

technical field [0001] The present invention relates to a sealed secondary battery suitable for a driving power supply, and more particularly to a sealed secondary battery having a low impedance and a sealing plate structure suitable for large current discharge, and a method for manufacturing the same. Background technique [0002] Among sealed secondary batteries, lithium-ion secondary batteries are used in a variety of applications due to their light weight, small size, and high energy density, ranging from consumer equipment represented by mobile phones to electric vehicles and electric Power supply for driving tools, etc. Especially in recent years, it has attracted much attention as a power supply for driving, and research towards high energy density and high output power is in the ascendant. The sealing plate of the lithium-ion secondary battery used in the current civilian equipment generally has the structure shown in FIG. 4 . Inside the metal filter 19 constitutin...

AI Technical Summary

Problems solved by technology

[0005] However, the problem to be solved for the sealing plate of the lithium ion secondary battery used in consumer equipment is that as the inner liner for sealing by caulking the metal filter, a molded liner made of synthetic resin such as polypropylene is usually used. Under the action of factors such as drop, vibration, and high temperature storage, the resin inner liner will cause a decrease in elastic force over time, which will lead to a decrease in caulking force, thereby reducing the contact resistance of internal parts. increase

[0006] In addition, the problem with the structure of JP-A-2000-90892 is that since the metal thin-walled valve body is not installed, the excessive current path cannot be blocked when the battery is mistakenly overcharged, etc., so the electrolytic The rapid decomposition of liquid and electrode active material is further promoted, causing the temperature of the battery to rise, which develops into a situation where gas is emitted

[0007] Furthermore, the problem with the structure of JP-A-2001-126695 is that although a part of the safety valve member and the metal cap are welded together, most of the sealing plate is mechanically joined together by caulking. Therefore, under the action of factors such as drop, vibration, and high-temperature storage, the caulking force will decrease with time, which will increase the contact resistance of internal parts, which will lead to an increase in the internal resistance of the battery.

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