What is filmless electromagnetism? What's the difference with membrane batteries?

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Today, let's discuss, what's the difference between the new non-membrane battery and the traditional membrane battery?

Let's be specific.

Difference between new lithium battery nonwoven separator and traditional lithium battery separator

In recent years, with the vigorous development of the lithium battery industry, the market demands higher and higher performance of lithium batteries. A series of problems such as the safety of lithium batteries, high-power charging and discharging, and the improvement of cruising range have also appeared. Upgrading every material in lithium batteries will definitely become a breakthrough to solve these problems. Non-woven diaphragm may become an important direction for upgrading existing polyolefin diaphragm.

First of all, from the perspective of materials, both PP/PE and nonwoven fabrics use polymer materials with different glass transition temperatures. Simply put, the glass transition temperature of PP/PE is lower than normal temperature. With the increase of temperature, the membrane material will become softer and softer.

Nonwoven fabrics have the advantages of high temperature resistance and high porosity. In addition, due to its three-dimensional pore structure, it can effectively avoid short circuit caused by acupuncture and improve the liquid retention rate.

Microporous polyolefin membranes are widely used in lithium batteries, with uniform micropores and a thickness of only 20 μ m. This membrane shrinks greatly after 150℃, and many enterprises add ceramic coatings on its surface to improve heat resistance. There are also foreign companies that use wet coating process to coat ceramic layer on the surface of non-woven fabrics, which makes the film not only have high safety at 220℃, but also have a longer cycle life after coating because the coating is rich in ceramic particles. Compared with microporous membrane, nonwoven fabric coated with ceramic membrane has better electrolyte wettability and ionic conductivity.

Special application of nonwoven diaphragm

The thickness of non-woven fabrics cannot be made very thin. At present, the thinnest non-woven diaphragm that can be mass-produced is made of cellulose with a thickness of 12- 15μm, and it is difficult to minimize the aperture.

In addition, if the obturator function is added, the cost will increase by 2-3 yuan /m2. However, there is no need to increase the closed-cell function in energy storage and power lithium batteries, so the non-woven separator is suitable for large batteries, especially for energy storage and power batteries with long cycle life requirements. At present, non-woven diaphragm is in the stage of small batch production and has not been used in large quantities. However, many battery manufacturers have shown great interest in this, and some are already conducting pilot tests.