Composition, method and device for applying a coating on a support

Abstract

A composition for applying a coating on a support at low temperature from a dispersion of at least a component of the coating to be deposited in the composition. The composition includes at least a strong and heavy solvent with a boiling point higher than 150° C. approximately, and a weak solvent with a boiling point less than 100° C. approximately. The solvents forming the composition must constitute a mixture that evaporates at a temperature less than 100° C. The composition is particularly useful for forming electrodes or electrolyte in lithium-ion batteries. The method and the device used for forming the coating use a dispersion spreader and an infrared lamp.

1 . (canceled) 
     
     
         2 . A process of applying a coating on a support, the process comprising:
 providing a composition including a strong solvent and a weak solvent, the strong solvent having a boiling temperature higher than about 150° C. and the weak solvent having a boiling temperature lower than about 100° C., the strong solvent and the weak solvent being present in a ratio capable of constituting a mixture that can evaporate at a temperature lower than 100° C.;   dispersing, in the composition, a component to be applied in the form of a coating on the support;   spreading the dispersion obtained by the dispersing on the support;   drying the dispersion to obtain the coating.   
     
     
         3 . The process according to  claim 2 , wherein the drying includes drying the dispersion at a temperature lower than 100° C. 
     
     
         4 . The process according to  claim 2 , wherein the drying includes drying the dispersion by a heating element. 
     
     
         5 . The process according to  claim 2 , wherein the drying includes drying the dispersion by an infrared lamp. 
     
     
         6 . The process according to  claim 2 , wherein the drying includes drying the dispersion by an infrared lamp and a heating element. 
     
     
         7 . The process according to  claim 2 , further comprising:
 adding a binder, to the composition, for the component dispersed in the dispersing prior to performing the dispersing.   
     
     
         8 . The process according to  claim 7 , further comprising:
 solubilizing the binder in the strong solvent;   combining the weak solvent with a diluting agent; and   mixing the result of the solubilizing and the combining to provide the mixture.   
     
     
         9 . The process according to  claim 2 , wherein the support is an electrode or an electrolyte in the form of film for a rechargeable electrochemical generator. 
     
     
         10 . The process according to  claim 2 , wherein the composition includes a diluting agent having a boiling temperature lower than about 80° C., the diluting agent having a property of relatively increasing a solubilization capacity of the mixture and of facilitating an evaporation of the strong solvent at a relatively lower temperature. 
     
     
         11 . The process according to  claim 2 , wherein the strong solvent is selected from N-methyl pyrolidone and cyclopentanone. 
     
     
         12 . The process according to  claim 2 , wherein the weak solvent is selected from acetone and ethyl acetate. 
     
     
         13 . The process according to  claim 10 , wherein the diluting agent is selected from toluene and benzene. 
     
     
         14 . The process according to  claim 10 , wherein the volume ratio of the mixture comprises less than 20% of the strong solvent, between 40% and 60% of the weak solvent and between 15% and 25% of the diluting agent. 
     
     
         15 . The process according to  claim 2 , wherein the component is present in the dispersion at the rate of 0.015 g/cc to 0.04 g/cc of the mixture. 
     
     
         16 . The process according to  claim 2 , wherein the percentage volume ratio of the weak solvent/diluting agent is between 80/20 and 65/25. 
     
     
         17 . The process according to  claim 2 , wherein the composition includes a binder for the component. 
     
     
         18 . The process according to  claim 7 , wherein the binder comprises fluorinated polyvinylidene. 
     
     
         19 . The process according to  claim 2 , wherein the component includes a graphite powder. 
     
     
         20 . The process according to  claim 19 , wherein the weight ratio between the graphite powder and the composition varies between 60:10 and 90:10. 
     
     
         21 . The process according to  claim 19 , wherein the component also includes cobalt oxide. 
     
     
         22 . A device for applying a coating on a support in the form of a film, the device comprising:
 a source of film support;   a feeding tank configured to contain a dispersion, the dispersion including a component dispersed in a composition, the composition including a strong solvent and a weak solvent, the strong solvent having a boiling temperature higher than about 150° C. and the weak solvent having a boiling temperature lower than about 100° C., the strong solvent and the weak solvent being present in a ratio capable of constituting a mixture that can evaporate at a temperature lower than 100° C.;   an unwinding unit to circulate the film support in the vicinity of the feeding tank;   a pouring unit to coat the film support by continuously pouring a predetermined quantity of the dispersion onto the film support when the film support is circulated in the vicinity of the feeding tank;   a winding unit to continuously transfer the coated film support to a receiving unit;   a motor to operate the unwinding unit, the winding unit and the receiving unit; and   a heating device to evaporate a liquid content of the dispersion at a temperature lower than 100° C. leaving a solid coating on the film support.   
     
     
         23 . The device according to  claim 22 , wherein the heating device includes at least one infrared lamp. 
     
     
         24 . The device according to  claim 23 , wherein the film support consists of a cross-linkable polymer, and the heating device also comprises at least one ultraviolet lamp to cross-link the cross-linkable polymer. 
     
     
         25 . The device according to  claim 22 , wherein the feeding tank includes an adjuster to adjust a width and a thickness of a deposit of the dispersion on the film support according to predetermined parameters.