Screen printing of microprotrusions for use as a space separator in an electrical storage device

Claim 1

A method of producing an array of substantially uniform electrically insulating microprotrusions on an electrode surface as a separator of electrodes of an electrical charge storage device, which method comprises: (a) obtaining an electrically insulating material which is essentially inert to electrolyte conditions which material has thixotropic properties at ambient temperature and pressure; (b) obtaining an electrode material comprising a thin flat electrically conducting metal sheet the center of which is coated on one or both flat surfaces with electrically conducting porous carbon or a porous metal oxide creating a coated flat electrode and securing the coated flat electrode in a holder; (c) placing a stencil having openings over the coated flat electrode; (d) contacting the top exterior stencil surface with the thixotropic material of step(a) so that portions of the material extrude through the stencil and contact the exterior surface of the coated electrode thus creating multiple discrete microprotrusions when a squeegee is brought across the top exterior stencil surface to cause contact of the bottom of the stencil with the coated electrode surface and the stencil is removed; (e) removing the coated electrode produced in step (d) from the holder; and (f) curing the applied multiple discrete microprotrusions whereby the microprotrusions essentially retain their shape and dimensions.

Claim 2

A method of producing an array of substantially uniform electrically insulating microprotrusions on an electrode surface as a separator of electrodes of an electrical charge storage device, which method comprises: (a) obtaining an electrically insulating material which is essentially inert to electrolyte conditions which material has thixotropic properties at ambient temperature and pressure; (b) obtaining an electrode material comprising a thin flat electrically conducting metal sheet the center of which is coated on one or both flat surfaces with electrically conducting porous carbon or a porous metal oxide creating a coated flat electrode and securing the coated flat electrode in a holder; (c) placing a stencil having openings over the coated flat electrode; (d) contacting the top exterior stencil surface with the thixotropic material of step(a) so that portions of the material extrude through the stencil and contact the exterior surface of the coated electrode thus creating multiple discrete microprotrusions when a squeegee is brought across the top exterior stencil surface to cause contact of the bottom of the stencil with the coated electrode surface and the stencil is removed; (e) removing the coated electrode produced in step (d) from the holder; and (f) curing the applied multiple discrete microprotrusions whereby the microprotrusions essentially retain their shape and dimensions.