Making and inspecting a web of vitreous lithium sulfide separator sheet and lithium electrode assemblies and battery cells

Abstract

A lithium ion-conductive solid electrolyte including a freestanding inorganic vitreous sheet of sulfide-based lithium ion conducting glass is capable of high performance in a lithium metal battery by providing a high degree of lithium ion conductivity while being highly resistant to the initiation and/or propagation of lithium dendrites. Such an electrolyte is also itself manufacturable, and readily adaptable for battery cell and cell component manufacture, in a cost-effective, scalable manner. An automated machine based system, apparatus and methods assessing and inspecting the quality of such vitreous solid electrolyte sheets, electrode sub-assemblies and lithium electrode assemblies can be based on spectrophotometry and can be performed inline with fabricating the sheet or web (e.g., inline with drawing of the vitreous Li ion conducting glass) and/or with the manufacturing of associated electrode sub-assemblies and lithium electrode assemblies and battery cells.

1 . A method of making a battery cell separator layer, the method comprising:
 i) providing a dense solid inorganic glass electrolyte sheet having first and second opposing principal side surfaces; and   ii) spectrophotometrically inspecting the sheet for defects or flaws.   
     
     
         2 . The method of  claim 1 , wherein the spectrophotometrically inspecting the glass sheet further comprises characterizing and evaluating any defects or flaws present at or within 10 μm of one or more of the first principal side surface and the second principal side surface of the solid electrolyte glass sheet. 
     
     
         3 . The method of  claim 1 , wherein the dense glass sheet is freestanding. 
     
     
         4 . The method of  claim 1 , wherein the first and second opposing surfaces are uncoated, and in direct contact with the ambient environment. 
     
     
         5 . The method of  claim 1 , wherein the spectrophotometric inspection is based on a comparison of incident and transmitted light intensities at various wavelengths. 
     
     
         6 . A method of making a battery cell component, the method comprising:
 i) providing an electrode subassembly comprising:
 a dense solid inorganic glass electrolyte sheet as an ionically conductive separator layer having first and second opposing principal side surfaces; and 
 a material layer coated on the first principal side surface; and 
   ii) spectrophotometrically inspecting the subassembly for defects or flaws comprising inspecting an interface between the dense glass sheet and the material layer for flaws or inclusions at the interface.   
     
     
         7 . The method of  claim 6 , wherein the material layer is reflective of light. 
     
     
         8 . The method of  claim 7 , wherein the material layer is a metal that is not lithium metal. 
     
     
         9 . The method of  claim 7 , wherein the spectrophotometric inspection is based on reflected light intensities at various wavelengths. 
     
     
         10 . A method of making a battery cell, the method comprising:
 i) providing an electrode assembly, comprising:
 a dense solid inorganic glass electrolyte sheet as an ionically conductive separator layer having first and second opposing principal side surfaces; and 
 a material layer comprising electroactive lithium disposed on the first principal side surface; and 
   ii) spectrophotometrically inspecting the electrode assembly for defects or flaws at an interface between the material layer and the glass sheet.   
     
     
         11 . The method of  claim 10 , wherein the spectrophotometric inspection involves light attenuation. 
     
     
         12 . The method of  claim 11 , wherein the light is in the visible region. 
     
     
         13 . The method of  claim 10 , wherein the material layer is lithium metal. 
     
     
         14 . The method of  claim 10 , wherein the material layer is a lithium alloy. 
     
     
         15 . The method of  claim 11 , wherein the light attenuation is used to characterize and evaluate concentrations of any scattering centers in the bulk of the glass sheet and at the interface between the glass sheet and the material layer. 
     
     
         16 . The method of  claim 10 , wherein changes in reflectivity of the interface are monitored in order to identify areas of low Li reactivity at the interface. 
     
     
         17 . The method of  claim 10 , wherein the method involves monitoring reactions at the interface in real time. 
     
     
         18 . The method of  claim 10 , wherein the spectrophotometric inspection is an automated inspection comprising:
 i. providing a source of light of a specified wavelength, or the wavelength selectable from a range of wavelengths;   ii. providing sensors for measuring intensity of the light;   iii. providing a computer that interfaces with the sensors for collecting light intensity data;   iv. shining the light at the solid electrolyte glass sheet for transmission or reflection measurements;   v. measuring the transmitted or reflected light intensity using said sensors; and   vi. storing data from said sensors using said computer.   
     
     
         19 . The method of  claim 18 , wherein the spectrophotometric inspection is performed inline with the fabrication of the electrode assembly. 
     
     
         20 . The method of  claim 19 , wherein the spectrophotometric inspection comprises spectrophotometrically inspecting the first and/or second principal side surface of the inorganic solid electrolyte glass sheet at a first glass sheet inspection station, and conveying the glass sheet to a second inspection station for inspecting the interface between the glass sheet and a material layer on the first principal side surface of the glass sheet. 
     
     
         21 - 35 . (canceled)