Electrode assembly and electrochemistry device comprising the electrode assembly

Abstract

The invention provides an electrode assembly and an electrochemistry device comprising the electrode assembly. The electrode assembly includes a plurality of unit batteries. Each unit battery includes an anode, a cathode, and a first separator between the anode and the cathode, and which overlaps a plurality of cells by enclosing full cell or bi-cell unit cells using a second separator, an electrode assembly is disclosed in which the average gas bubble diameter (d2) of the second separator is greater than the average gas bubble diameter (d1) of the first separator amidst the unit cells. The electrode assembly of the invention has raised wettability and raised performance of removing gasses generated by side reaction of the batteries, so that electrolytes will not leak and the expansion of the batteries is smaller. Thus good battery performance can be maintained when the batteries are in long-term usage, and deformation of the batteries due to outside bumping is smaller.

Description

[0001] Cross References to Related Applications [0002] This application claims priority from Korean Patent Application No. 10-2013-0131567 filed in Korea on Oct. 31, 2013, which is incorporated herein by reference. technical field [0003] The present invention relates to electrode assemblies, and more particularly to electrode assemblies that provide improved wetting and degassing performance for electrochemical devices. Background technique [0004] Recently, there has been an increasing interest in energy storage technologies. Electrochemical devices have been widely used as power sources in the fields of mobile phones, camcorders, notebook computers, PCs, and electric vehicles, leading to meticulous research and development thereof. In this regard, electrochemical devices are a subject of great interest. In particular, the development of rechargeable secondary batteries has been the focus of attention. In particular, according to the recent trend of downsizing and l...

AI Technical Summary

Problems solved by technology

Due to the deformation of the electrode assembly, the space between the electrodes becomes uneven, rapidly deteriorating battery performance, and an internal short circuit occurs that threatens battery safety

In addition, the winding of the positive and negative electrodes in sheet form is difficult to maintain a uniform distance between the positive and negative electrodes, and it is also difficult to quickly wind them, thus being disadvantageous in terms of productivity

[0008] Second, since a stacked type electrode assembly is prepared by sequentially laminating a plurality of positive and negative electrode units, a separate step is required to transfer plates to produce the units, and sequential lamination requires a lot of time and effort, so its productivity Low

In fact, it is difficult to obtain sufficient soaking time due to productivity problems

As a result, the electrolyte does not impregnate the separator sufficiently so that the separator is less wetted and unimpregnated electrolyte leaks under harsh conditions

[0014] In addition, gas generated by electrolyte decomposition and battery side reactions causes loosening in the battery, thereby deteriorating battery performance

If the gas generated by the side reaction cannot be released, it is difficult to suppress the expansion of the battery

According to this, the battery deteriorates in its performance and is easily deformed by external impact, so that the strength of the battery decreases

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