Micromachined electrolyte sheet, fuel cell devices utilizing such, and micromachining method for making fuel cell devices

Abstract

A sintered electrolyte sheet comprising: a body of no more than 45 μm thick and laser machined features with at least one edge surface having at least 10% ablation. A method of micromachining the electrolyte sheet includes the steps of: (i) supporting a sintered electrolyte sheet; (ii) micromachining said sheet with a laser, wherein said laser has a wavelength of less than 2 μm, fluence of less than 200 Joules/cm 2 , repetition rate (RR) of between 30 Hz and 1 MHz, and cutting speed of preferably over 30 mm/sec.

1 . A sintered electrolyte sheet comprising: a body of no more than 45 μm thick and at least one laser machined feature with at least one edge surface having at least 10% ablation. 
     
     
         2 . The electrolyte sheet of  claim 1 , wherein said at least one edge surface has more than 50% fracture and less than 50% ablation. 
     
     
         3 . The electrolyte sheet according to  claim 1 , wherein said electrolyte sheet has multiple electrodes situated on said electrolyte sheet. 
     
     
         4 . The electrolyte sheet of  claim 1 , wherein said electrolyte sheet is zirconia based and includes a micromachined edge, and the relative concentration of zirconium at the micromachined edge is higher than at another area that is located at the surface of the electrolyte sheet further from the laser micromachined edge. 
     
     
         5 . The electrolyte sheet of  claim 1 , wherein said electrolyte sheet has a laser micromachined surface and the laser micromachined surface has average crystal grain size of less than 1 micron. 
     
     
         6 . The fuel cell device including electrolyte sheet of  claim 1 , and at least one anode and cathode pair, wherein said features are via holes with diameters less than 75 microns. 
     
     
         7 . The fuel cell device of  claim 6 , with length of larger than 30 cm, and with part-to-part via hole registration repeatability of less than +/−200 microns. 
     
     
         8 . An electrolyte of  claim 1  having edge strength of greater than 1.8 GPa. 
     
     
         9 . The electrolyte sheet according to  claim 1  wherein said electrolyte sheet is zirconia based electrolyte sheet with at least one edge surface exhibiting 100% ablation and grain growth at the ablated edge surface, wherein the grain size of the ablated edge surface is less than 2 μm. 
     
     
         10 . The electrolyte sheet according to  claim 1  wherein said electrolyte sheet has an un-printed border, said boarder being less than 5 mm wide. 
     
     
         11 . A method of micromachining an electrolyte sheet comprising: (i) supporting a sintered electrolyte sheet; (ii) micromachining said sheet with a laser, wherein said laser has a wavelength of less than 2 μm, fluence of less than 200 Joules/cm 2 , and repetition rate (RR) of between 30 Hz and 1 MHz, pulse duration less than 1 μs. 
     
     
         12 . The method according to  claim 1 , wherein said laser is a 355 nm nanosecond laser. 
     
     
         13 . The method of micromachining an electrolyte sheet according to claim  23 , wherein said laser has a pulse duration <1 μs, wavelength <400 nm, and: fluence is between 5 Joules/cm 2  and 200 Joules/cm 2 , repetition rate (RR) of at least 1 KHz, and cutting speed >50 mm/sec. 
     
     
         14 . A method of making multiple fuel cell devices, wherein multiple fuel cell devices (i) are at least partially fabricated on a single sheet of electrolyte; and (ii) are laser cut, separating them from one another according to the micromachining method of  claim 11 . 
     
     
         15 . The method of micromachining an electrolyte sheet according to  claim 11 , said method including cutting off by micromachining more than 1 mm of at least one side of the electrolyte sheet, so as to remove at least a portion of electrolyte sheet edge curl. 
     
     
         16 . The electrolyte sheet of  claim 11 , wherein the micromachining is performed by ablation in conjunction with auto-cleaving. 
     
     
         17 . The method of micromachining an electrolyte sheet according to  claim 11 , wherein said micromachining includes cutting holes or trimming perimeter of the electrolyte sheet trough its entire thickness. 
     
     
         18 . The method of micromachining an electrolyte sheet according to  claim 11 , wherein said electrolyte sheet is a corrugated sheet and said micromachining method produces via holes in said electrolyte sheet. 
     
     
         19 . The method of micromaching an electrolyte sheet according to  claim 11 , including a step of laser micromachining at least one additional layer situated on said electrolyte sheet. 
     
     
         20 . The method according to  claim 17 , wherein said holes are produced with a lip and said lip is trimmed off with a laser to a height of less than 5 μm.