Long life thin film battery and method therefor

• US 6,994,933 B1
• Filed: 09/16/2002
• Issued: 02/07/2006
• Est. Priority Date: 09/16/2002
• Status: Expired due to Fees

• Current Assignee: Oak Ridge Micro Energy, Inc.
• Original Assignee: Oak Ridge Micro Energy, Inc.
• Inventors: Bates, John B.
• Primary Examiner(s): Ryan, Patrick Joseph
• Assistant Examiner(s): Martin, Angela J.
• Application Number:
  US10/244,260
• Time in Patent Office: 1,240 Days
• Field of Search: 429/162, 429/163, 429/127, 429/124, 429/231.95
• US Class Current: 429/162
• CPC Class Codes: H01M 50/11 having a chip structure, e.g. micro-sized batteries integrated on chips
• CPC Class Codes: H01M 50/117 Inorganic material
• CPC Class Codes: H01M 50/119 Metals
• CPC Class Codes: H01M 50/121 Organic material
• CPC Class Codes: H01M 50/122 Composite material consisting of a mixture of organic and inorganic materials
• CPC Class Codes: H01M 50/124 having a layered structure
• CPC Class Codes: H01M 50/1245 characterised by the external coating on the casing
• CPC Class Codes: H01M 50/126 comprising three or more layers
• CPC Class Codes: H01M 50/131 characterised by physical properties, e.g. gas permeability, size or heat resistance
• CPC Class Codes: H01M 50/141 for protecting against humidity
• CPC Class Codes: H01M 6/12 with flat electrodes
• CPC Class Codes: H01M 6/40 Printed batteries , e.g. thin film batteries

Abstract

A thin film battery including an anode layer, a cathode layer and a solid electrolyte layer. The battery also includes, a planarization layer applied to the thin film battery. The planarization layer has a surface roughness of no more than about 1.0 nanometers root mean square and a flatness no larger than about 0.005 cm/inch. A barrier layer is applied to the planarization layer. The barrier layer is provided by one or more layers of material selected from the group consisting of polymeric materials, metals and ceramic materials. The planarization layer and barrier layer are sufficient to reduce oxygen flux through the barrier layer to the anode layer to no more than about 1.6 μmol/m²-day, and H₂O flux through the barrier layer to the anode layer to less than about 3.3 μmol/m²-day thereby improving the life of the thin film battery.

Claims

1. A method for improving the life of a thin film rechargeable battery having a solid electrolyte comprising the steps of:

providing a thin film battery having an anode layer reactive with oxygen and water vapor;

applying a planarization material over the anode layer and thin film battery to provide a relatively smooth, substantially pinhole free planarization layer, wherein the surface roughness of the planarization layer is no more than about 1.0 nanometers root mean square, and the planarization material in the planarization layer is substantially non-reactive with the anode layer; and

applying one or more barrier layers to the planarization layer, the barrier layers being selected from the group consisting of metal materials, ceramic materials, and polymeric materials;

whereby the planarization layer and the one or more barrier layers are effective to provide a thin film battery having an extended life.

2. The method of claim 1 wherein the thin film battery comprises a lithium or lithium ion containing anode.

3. The method of claim 1 wherein the planarization material is selected from the group consisting of acrylates, diacrylates, triacrylates, and polyolefins that do not contain an organic acid group thereon.

4. The method of claim 1 wherein the planarization layer has a flatness no greater than about 0.005 cm/in.

5. The method of claim 1 further comprising applying a metal layer to the anode layer prior to applying the planarization material to the anode layer and thin film battery, wherein the metal layer is provided by a metal that does not significantly alloy with the anode layer.

6. The method of claim 5 further comprising depositing a layer of lithium phosphorus oxynitride on the metal layer prior to applying the planarization material to the anode layer and thin film battery.

7. The method of claim 6 further comprising depositing magnesium over the planarization layer to provide a getter layer reactive with oxygen and H₂O.

8. The method of claim 1 further comprising depositing magnesium over the planarization layer to provide a getter layer reactive with oxygen and H₂O.

9. A long-life, thin film rechargeable battery, comprising:

a support substrate having a support surface;

a cathode current collector spaced-apart from an anode current collector deposited on the support surface of the substrate;

a cathode layer deposited on a portion of the cathode current collector;

a solid electrolyte layer deposited on the cathode material, substrate and a first portion of the anode current collector;

an anode layer deposited on the electrolyte layer, and a second portion of the anode current collector to provide a thin film battery stack;

a planarization material applied over the thin film battery stack to provide a relatively smooth planarization layer having a surface roughness of no more than about 1.0 nanometers root mean square, and the planarization material in the planarization layer is substantially non-reactive with the anode layer;

one or more barrier layers applied over the planarization layer, the barrier layers being selected from the group consisting of metal materials, ceramic materials, and polymeric materials;

whereby the planarization layer and the one or more barrier layers are effective to provide a thin film battery having an extended life.

10. The long-life, thin film battery of claim 9 wherein the anode layer comprises lithium or a lithium ion containing material.

11. The long-life, thin film battery of claim 9 wherein the planarization material is selected from the group consisting of acrylates, diacrylates, triacrylates, and polyolefins that do not contain an organic acid group thereon.

12. The long-life, thin film battery of claim 9 wherein the planarization layer has a flatness no greater than about 0.005 cm/in.

13. The long-life, thin film battery of claim 9 further comprising a metal layer deposited on the anode layer between the anode layer and the planarization layer, wherein the metal layer is provided by a metal that does not significantly alloy with the anode layer.

14. The long-life, thin film battery of claim 13 further comprising a layer of lithium phosphorus oxynitride deposited on the metal layer between the planarization layer and the metal layer.

15. The long-life, thin film battery of claim 9 further comprising a magnesium layer deposited on the planarization layer to provide a getter layer reactive with oxygen and H₂O.

16. A thin film rechargeable battery including an anode layer, a cathode layer and a solid electrolyte layer, the improvement comprising:

a planarization layer applied to the thin film battery, the planarization layer having a surface roughness of no more than about 1.0 nanometers root mean square and a flatness no greater than about 0.005 cm/inch; and

a barrier layer applied to the planarization layer, wherein the planarization layer and barrier layer are sufficient to reduce oxygen flux through the barrier layer to the anode layer, and H₂O flux through the barrier layer to the anode layer to provide a thin film battery having an extended life wherein the barrier layer is provided by one or more layers of material selected from the group consisting of polymeric materials, metals and ceramic materials.

17. The thin film battery of claim 16 wherein the planarization layer is selected from the group consisting of acrylates, diacrylates, triacrylates, and polyolefins that do not contain an organic acid group thereon.

18. The thin film battery of claim 16 further comprising a metal layer deposited on the anode layer between the anode layer and the planarization layer, wherein the metal layer is provided by a metal that does not significantly alloy with the anode layer.

19. The thin film battery of claim 18 further comprising a layer of lithium phosphorus oxynitride deposited on the metal layer between the planarization layer and the metal layer.

20. The thin film battery of claim 16 further comprising a magnesium layer deposited on the planarization layer to provide a getter layer reactive with oxygen and H₂O.

21. The thin film battery of claim 16 wherein the solid electrolyte layer comprises a lithium phosphorus oxynitride material containing a sulfide ion dopant wherein the atomic ratio of sulfide ion to phosphorus ion (S/P) in the electrolyte ranges from greater than 0 up to about 0.2 and wherein the composition is represented by the formula:

Li_wPO_xN_yS_z,

where 2x+3y+2z=5+w, x ranges from about 3.2 to about 3.8, y ranges from about 0.13 to about 0.46, z ranges from greater than zero up to about 0.2, and w ranges from about 2.9 to about 3.3.