Solid state battery fabrication
View Patent ↗Embodiments of the invention generally relate to solid state battery structures, such as Li-ion batteries, methods of fabrication and tools for fabricating the batteries. One or more electrodes and the separator may each be cast using a green tape approach wherein a mixture of active material, conductive additive, polymer binder and/or solid electrolyte are molded or extruded in a roll to roll or segmented sheet/disk process to make green tape, green disks or green sheets. A method of fabricating a solid state battery may include: preparing and/or providing a green sheet of positive electrode material; preparing and/or providing a green sheet of separator material; laminating together the green sheet of positive electrode material and the green sheet of separator material to form a laminated green stack; and sintering the laminated green stack to form a sintered stack comprising a positive electrode and a separator.
1. A method of fabricating a solid state battery comprising:
providing a green sheet of positive electrode material;
providing a green sheet of separator material;
laminating together said green sheet of positive electrode material and said green sheet of separator material to form a laminated green stack;
sintering said laminated green stack to form a sintered stack, said sintered stack comprising a positive electrode and a separator;
laminating a negative electrode to said sintered stack; and
incorporating a layer of silicon or copper nitride at an interface between said negative electrode and said sintered stack;
wherein said negative electrode is a lithium metal electrode.
2. The method as in claim 1 , further comprising depositing a positive current collector on the surface of said positive electrode.
3. The method as in claim 1 , wherein said green sheet of positive electrode material is a continuous sheet, and wherein said green sheet of separator material is a continuous sheet.
4. The method as in claim 1 , wherein said green sheet of positive electrode material is attached to a positive current collector.
5. The method as in claim 1 , wherein said green sheet of positive electrode material comprises:
a Li(Mn,Co,Ni)O 2 material; and
a binding polymer.
6. The method as in claim 5 , wherein said green sheet of positive electrode material further comprises an electronic conductive additive.
7. The method as in claim 1 , wherein said green sheet of separator material comprises:
a pure ion conductor material; and
a polymer binder.
8. The method as in claim 7 , wherein said pure ion conductor material is Li 7-x La 3 Zr 2-x Ta x O 12 and x is greater than 0 and less than or equal to 1.
9. The method as in claim 1 , further comprising depositing a negative current collector on a surface of said negative electrode.
10. The method as in claim 1 , wherein said green sheet of positive electrode material is a segmented sheet, and wherein said green sheet of separator material is a segmented sheet.
11. The method as in claim 1 , wherein said solid state battery comprises lithium conducting solid electrolyte and LiNbO 3 coated LiCoO 2 active material.
12. The method as in claim 1 , wherein said green sheet of separator material comprises doped Li 7 La 3 Zr 2 O 12 garnet solid electrolyte.
13. The method as in claim 1 , wherein said green sheet of separator material comprises a sulphide based solid electrolyte.
14. The method as in claim 13 , wherein said sulphide based solid electrolyte is Li 10 GeP 2 S 12 .
15. The method as in claim 1 , wherein said green sheet of separator material comprises material selected from the group consisting of doped Li 7 La 3 Zr 2 O 12 garnet solid electrolyte and sulphide based solid electrolyte.
16. The method as in claim 1 , wherein said laminating said negative electrode to said sintered stack comprises passing said negative electrode and said sintered stack through pinch rollers.
17. The method as in claim 1 , wherein said layer of silicon or copper nitride is a layer of silicon.
18. The method as in claim 1 , wherein said layer of silicon or copper nitride is a layer of copper nitride.
19. A method of fabricating a solid state battery comprising:
providing a green sheet of positive electrode material;
providing a green sheet of separator material;
laminating together said green sheet of positive electrode material and said green sheet of separator material to form a laminated green stack;
sintering said laminated green stack to form a sintered stack, said sintered stack comprising a positive electrode and a separator;
laminating a negative electrode to said sintered stack; wherein said green sheet of separator material comprises a sulphide based solid electrolyte Li 10 GeP 2 S 12 , wherein said negative electrode is a lithium metal electrode; and
incorporating a layer of silicon or copper nitride at an interface between said negative electrode and said sintered stack.