Development of the Mechanical Battery

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Development of the Mechanical Battery

• Texas AM University Kingsville
• Javier Lozano MEEN Senior
• Luis Muratalla MEEN Junior
• Eli Hatfield EEEN Sophomore
• Gary Garcia MEEN Freshman
• Richard Rivera MEEN Freshman
• Jonathan Boehm CEEN Freshman
• Faculty Advisor Dr. Larry Peel

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Project Background

• Design a safe, efficient mechanical battery that
  stores energy in a mechanical form, for use on
  the space station.
• Energy will be stored into Fiber Reinforced
  Elastomer composites.
• Rechargeable and portable form of energy storage.

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Design Objectives

• Battery must be lightweight, compact
• Must be free of hazardous chemicals and toxic
  materials
• Have an energy density near or above that of an
  electrochemical battery
• Must be rechargeable electrically and manually
• Mechanically stored energy with an electrical
  energy output
• Prevent overcharging and battery failure

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Semester Objective

• Complete the frame
• Complete Design layout
• Create solid models
• Brake
• Clutch
• Bearings
• Meet Deadlines
• College Station Presentation
• End of Semester report
• Produce Deliverables
• Semester Presentation
• Report to NASA mentors
• Report to College Station

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Project History

• The team went from a smaller battery to a larger
  battery
• Easier Fabrication
• Higher energy density
• From having the strips in torsion to tension
• Analyzed composite strips to compare between
  circular torsion, rectangular torsion, and
  rectangular tension
• Initial dimensions .4 x .8 x 13 in torsion
• Optimal Fiber Orientation for best combination of
  elasticity and stiffness.

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Current Design
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Current Work

• Incorporation of Brake into the system
• Attempt to alter motor to strip gear ratio
• Structural Analysis
• Frames
• Mounting plates
• Further Analysis on Composite Strips
• Test all components of the electrical portion

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Gearing System

• Clustered Design
• Motor Gear
• Generator Gear
• Composite strip gear
• Intermediate gear
• Engagement gear

• Engagement arm
• Engagement gear on end allows engagement of
  either motor or generator
• Gear Ratio Information
• 21 Ratio from Motor to shaft
• 0.251 Ratio from Shaft to Generator

Motor Gear
Composite Shaft Gear
Engagement Gear
Generator Gear
Intermediate Gear
Engagement Arm
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Braking System

• Electromagnetic Brake
• Use Mechanism to stop and lock Composite Strips
  in the stretched position
• Clutch
• Use electromagnetic brake as clutch
• Benefits
• Single Unit
• Less Controllers
• Lighter

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Composite Strip Design

• Strip dimensions 2.25 x .1 x 15
• IM7 Carbon fibers with a polyurethane RP 6442/fr
  1040 matrix
• Ply angles tested /-45, /-60 or /-75
• Elements able to stretch 150
• A time delay between stretching and releasing
  causes energy loss.

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Energy Data
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Energy Loss Data
Both Started at 100
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External Frame

• An aluminum frame covered by a composite skin
• Current dimensions
• 24 x 14 x 8
• Aluminum angle frame
• Thickness of 1/8
• 1 x 1 leg length
• Frame adds mounting capability
• Composite Skin provides stiffness, strength and
  safety

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Building The Frame

• Bolt Vs. Weld
• Vibration
• Strength
• Re-buildable
• Bracket Design
• Frame Corners
• Eliminate Offset
• Better Fit

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Internal Mounting Fixture

• Provides mounting surface to attach parts
• Provides extra support
• Provides mounting of rollers for the strips to
  fully stretch more easily
• Separates gear train from internal parts

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Completed Solid Model
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Energy Conversion

• Purpose
• Convert elastic potential energy to kinetic
  energy, to electrical energy and vice versa
• Components
• Electric Motor
• Generator
• Clutch
• Brake

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Power Generation

• 12 VDC, 20 amp output
• Charge Batteries
• Power 12 volt DC equipment

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Re-charge System

• Recharging
• Easy recharges mechanical battery (Stretches
  composite strips)
• Operate at 120 VAC or 24VDC
• Motor Specifications
• 24 VDC
• 1/3 HP
• 11.7 in lbs Torque
• Problems
• Weight and size
• Rotational speed

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Current Schedule
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Work To Come

• Possibly revise electrical portion
• Finish Building the System
• Finish Building Frame
• Install internal components
• Incorporate Electrical Portion
• Test and Analyze results
• Attempt to Refine Design

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Conclusion

• The fabrication of the frame is almost complete
• The team decided to weld parts of the frame vs.
  bolting
• Completion of gear analysis excel program
• 21 Ratio from motor to composite strip shaft
• 0.251 Ratio from composite strip shaft to
  generator
• Material relaxation is an issue with the strips
• Likely will have much lower energy density than
  expected in battery.
• Battery is best suited for high intensity low
  duration energy output.

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Special Thanks

• Space Engineering Institute
• Magda Lagoudas
• Dr. Judith Jeevarajan
• Dr. Larry Peel
• Mr. Dustin Grant
• NASA (Prime Grant No. NCC9-150)
• TEES (Project No. 32566-681C3)
• Texas AM University Kingsville
• TAMUK staff and faculty

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Any Questions?