Portable Fuel Cell Charger (Input Side)

By: Aishwarya Singh and Rebecca Roecker(Team 59)

Introduction:

● People want to be able to take energy with them to grid-inaccessible places.

● To meet this demand, we require a power supply that is :

● Durable● Lightweight● Easy to use● Energy-rich

Background: Fuel Cells

● Open system electrochemical reactor.

● Uses redox reactions across a catalyzing membrane.

● Advantage vs Batteries: energy capacity is limited only by (scalable) fuel supply.

Background: Fuel Cells● Most common fuel is H2.● H2 has several issues:

○ Production○ Transport○ Safety

● Alternatives:○ Methanol.○ Ethanol.

■ Our choice.

Design: Block Diagram

Build: Fuel Cell Module● Horizon FCJJ-42 science

module.

● Ethanol in, acetic acid out reaction pathway.

● 5 to 15% ethanol in water.

● Tests done outside lab; no liquids in lab.

Build: Fuel Cell Module

Reaction Stage Chemical Equation

Anode (Oxidation)(1) C2H5OH → CH3CHO + 2e- + 2 H+

(2) CH3CHO + H2O → CH3COOH + 2e- + 2H+

Cathode (Reduction) O2 + 4H+ + 4e- → 2H2O

Total Reaction C2H5OH + O2 → CH3COOH + H2O

Current = Fuel Consumption 1 ethanol molecule = 2 electrons

Build / Test: Fuel Cell

"The Power Performance Curve for Engineering Analysis of Fuel Cells" -Kevrekidis et. al., Dept. of Chemical Engineering, Princeton University

Performance: Fuel Cell

Performance: Fuel Cell

Performance: Fuel Cell

Performance: Fuel Cell

Performance: Fuel Cell

Build: Fuel Cell to Battery● Boost Converter

● 1 LiPo battery charging

voltage is 4.2 + or - .03 Volts

● 7 batteries in series so

Vo = 7*4.2 = 29.4

● All components rated at 40

volts 2 Amps

● Fuel cell is only 0.83 Volts

Build: Fuel Cell to Battery Equations

Testing: Fuel Cell to Battery

Build: External Charging Circuit● Started with a 40 Volt .5 Amp HP

charger● Need to step down the voltage

from 40 to 29.4 Volts

Build: Battery Pack● Constructed a

battery pack accumulator.

● 2 sets of 7 GMBPower GMB652535 lithium polymer cells in parallel.

● Requirements set by our output team needs.

Requirements & Verifications

● Battery Pack:○ >= 24 V nominal operating voltage? Yes.○ >= 30 W sustained power? Yes.

● Power Conversion Circuits: ○ Required to meet parameters as described earlier.

○ Parameters met? No. Why?■ Components, impractical nature of source.

Requirements & Verifications

● Fuel Cell Module:○ Works in itself? Yes.

○ Shows fuel cell output character? Yes.

○ Usable as a source? Absolutely Not. Why?■ Reaction pathway. Carbon-to-carbon bonds.

■ Too small scale?● Ethanol to Acetic Acid cell of proper scale would be heavy.● Several hundred FCJJ-42s would be required!

Conclusions

Questions?

The End