1. 11/8/2000 1 Development of Lithium Batteries for Powering Sensor Arrays SFR Workshop November 8, 2000 Nelson Chong, James Lim, Jeff Sakamoto and Bruce Dunn Los Angeles, CA 2001 GOAL: To develop a thermally robust inorganic electrolyte and integrate lid to battery encapsulation scheme by 9/30/2001.

2. 11/8/2000 2 Motivation In order to power SMART wafers, a low profile, thermally stable, high energy density battery must be used. Lithium-V 2 O 5 thick film batteries are used to power SMART wafers. On board power enables in-situ data acquisition during a wafer processing step, such as temperature conditions across the wafer during baking or plasma etching. Advanced fabrication and encapsulation to enhance battery performance under vacuum and high temperature conditions. Sensor Array requirements

3. 11/8/2000 3

4. 4 Room Temperature operation: 2mA discharge to 2.5 volts. 050001000015000 2.0 2.5 3.0 3.5 4.0 4.5 Time (Sec) E (Volts) 2mA discharge 1mA charge Specific capacity of cathode~105mAh/g Battery Characteristics: Capacity Cycling

5. 11/8/2000 5 Alternating discharge at 85°C and room temperature. Discharge Charge T=85 to 110°C 2mA discharge to 2.5 volts. Discharge time: At 85  C: t=1.27 to 1.41 hrs. At 25  C: t=0.59 to 1.39 hrs. Minimum acceptable capacity Thermal Cycling Experiments

6. 11/8/2000 6 Battery Encapsulation and Lid Design Encapsulation with low viscosity epoxy (EP30 from Master Bond) Viscosity=400 to 500 cps at room temperature. Cure time=18 to 24 hrs at room temperature Encapsulation with 5 minute epoxy Cure time= 5 mins.

7. 11/8/2000 7 Polymer Electrolyte 1 21 mole % PAN 38 mole %EC 8 mole % LiClO 4 33 mole %PC T=125 °C to 140 °C Battery Encapsulation 75 wt% Vanadium Oxide Aerogel, 20wt% Carbon Black, 5 wt% PVDF Solvent: PC: C 6 H 12 =1:1 1. K.M. Abraham, J. Electrochem. Soc., 137, 5 (1990). Lithium pressing Apply polymer Electrolyte Celgard ® 3401 Slurry sprayed onto cathode current collector Cathode stacking Battery Fabrication

8. 11/8/2000 8 Inorganic/Organic Electrolyte Electrolyte 1M Li Imide 0.5 cc PC 2.5 cc PEGdm 250 Fumed Silica R805 particles/aggregates Silica Network van der Waals; electrostatic interactions; hydrogen bonding Battery successfully prepared with inorganic/organic Electrolyte (170 mAh/g) Li + conduction liquid polymer *Ref. J. Fan, P. Fedkiw J. Electrochem. Soc. Vol. 144, No. 2, Feb. 1997 Thermal stability 137 o C Thixotropic properties

9. 11/8/2000 9 2002 and 2003 Goals Integrate the inorganic electrolyte into the battery structure. Develop an in-situ lithium formation process by 9/30/2003. Battery operation between room temperature and 150 o C. Battery survivability to soldering operations by 9/30/2003.