Highly-porous separator film with a coating

A technology of porosity and coating, applied in the field of membrane preparation, can solve the problems of unsatisfactory mechanical strength, poor penetration resistance, high tearing tendency, etc.

Inactive Publication Date: 2014-08-13
TREOFAN GERMANY GBMH & CO KG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, their mechanical strength in the transverse direction is still unsatisfactory here, so that their penetration re

Method used

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  • Highly-porous separator film with a coating
  • Highly-porous separator film with a coating
  • Highly-porous separator film with a coating

Examples

Experimental program
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preparation example Construction

[0142] Preparation of the membranes mentioned in the examples:

[0143] Film Example 1

[0144] Calcium pimelate as a nucleating agent is copolymerized with isotactic polypropylene homopolymer (melting point 162°C; MFI3g / 10min), propylene homopolymer and propylene block in a mixer at a concentration of 0.04% by weight. The pellets formed were mixed and processed in a twin-screw extruder (shell temperature 240°C and 200 l / min -1 ) melted. After the extrusion process, the melt was extruded from a slot die at an extrusion temperature of 245°C to form a monolayer film.

[0145] The membrane has the following composition:

[0146]

[0147] The film also contains conventional amounts of stabilizers and neutralizers.

[0148] After extrusion, the polymer mixture is drawn out on the first take-out roll and another three-roll set, cooled and solidified, then longitudinally stretched, transversely stretched and shaped, wherein the following conditions are specifically selected: ...

Embodiment 1

[0175] A silicate coating with the composition of Coating 1 (Table 1) was manually applied onto a microporous BOPP membrane (Membrane Example 1) using a wire knife coater (wire diameter: 0.4 mm). Wetting of the membrane with the ceramic suspension was uniform. The coated film was then dried in a drying oven at 90° C. for one hour. After drying, the coating showed good adhesion to the film. Next, the coating weight, the thickness of the coating layer and the permeability to air were determined using the Gurley value. Only a small increase in the Gurley value was observed, from 180s to 210s.

Embodiment 2

[0177] A silicate coating with the composition of Coating 2 (Table 1 ) was manually applied onto the microporous BOPP membrane (Membrane Example 1 ) using a wire knife coater (wire diameter: 0.4 mm). Coating Solution 2 differs from Coating 1 by a higher proportion of PVDC binder. After coating, the wetting of the membrane with the ceramic suspension was uniform. The coated film was dried again in a drying oven at 90° C. for one hour. After drying, the adhesion of the coating to the film was better than Example 1. In addition, the air permeability (Gurley value) is significantly improved for almost the same coating coat weight. Observe that the Gurley value increases from 180s to 420s.

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Abstract

The invention relates to a bi-axially oriented, single or multi-layered porous film comprising at least one porous layer that contains at least one propylene polymer, (i) the porosity of this porous film being between 30% and 80%, (ii) the permeability of the porous film being <1000s (Gurley value), and this being characterized in that (iii) said porous film has an inorganic, preferably ceramic, coating and that (iv) the coated porous film has a Gurley value of <1500s. In addition, the invention also relates to a method for producing such a film as well as to the use thereof in high-energy or high-power systems, particularly in lithium, lithium-ion, lithium-polymer, and alkaline-earth batteries.

Description

technical field [0001] The present invention relates to coated porous membranes and their use as separators, as well as processes for the production of said membranes. Background technique [0002] Modern devices require energy sources that can be utilized spatially independently, such as batteries or accumulators. The disadvantage of batteries is that they must be disposed of. For this reason, accumulators (secondary batteries) are increasingly being used, which can be recharged repeatedly by means of charging devices connected to the power supply system. For example, a conventional nickel-cadmium battery (NiCd-battery) can achieve a service life of approximately 1000 charge cycles with proper use. [0003] Lithium, lithium-ion, lithium-polymer and alkaline-earth metal batteries are increasingly used as accumulators in high-energy or high-performance systems. [0004] Batteries and accumulators always consist of two electrodes immersed in an electrolyte solution and a se...

Claims

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Application Information

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IPC IPC(8): H01M2/16H01M2/14B29C55/00B29C55/14C08J5/18C08K5/098C08L23/12C08J7/043H01M50/406H01M50/417H01M50/434H01M50/449H01M50/489H01M50/491
CPCH01M2/1686C08J7/06B32B27/32C08L23/12B29C55/12H01M10/0525B29C55/005H01M2/1646C08J2323/12H01M2/1653H01M2/145B29C55/143H01M2/166H01M50/446H01M50/449H01M50/491H01M50/489H01M50/417H01M50/434H01M50/406C08K5/0083C08K5/098C08L53/00Y02E60/10C08J7/043C08J5/22C08K3/00C08J5/18H01M50/431H01M10/052H01M10/054
Inventor B·施密茨D·布什D·克莱恩
Owner TREOFAN GERMANY GBMH & CO KG
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