How to power your smartphone for a week!. 2 Presentation name What is a battery? A device that stores chemical energy in its active materials and converts.

How to power your smartphone for a week!

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What is a battery?

• A device that stores chemical energy in its active materials and converts it, on demand, into electrical energy by means of an electrochemical reaction– Electrochemical reaction is a chemical

reaction involving the transfer of electrons

• Batteries are made up of one or more basic electrochemical units called cells.– Cells are usually connected in series

to increase the voltage.

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Electrolyte

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Electron flow

Ionflow

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Types of batteries

• Primary batteries are used once and thrown away, like the alkaline batteries used in portable CD players– Electrochemical reactions are not reversible

and active materials cannot be restored to their original state.

• Secondary (or rechargeable) batteries can be used many times, like the battery in cell phones and laptop computers– The electrochemical reactions are reversible,

and the active materials can be restored to their original chemical composition.

Secondary66%

Primary34%

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Widely used rechargeable batteries

• Lead acid (30-40 Wh/kg, 70-92% eff., 2V)– Over 100 years old, and still the most widely used

rechargeable battery in the world.

• Nickel metal hydride (30-80 Wh/kg, 66% eff., 1.2 V)– A high power battery chemistry similar to nickel cadmium,

introduced in the 1980s. It is environmentally friendly, contains no toxic cadmium, and is replacing NiCd in many applications.

• Lithium ion (160 Wh/kg, 99.9% eff., 3.6-3.7V)– The newest and fastest growing rechargeable battery

technology.

– Theoretical capacity: 150-275mAh/g

Main concerns: large volumes, liquid technology, leakage, and toxicity

Market share

51%

31%

8%

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Real batteries

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Research batteries at ORNL

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Actual technology and materials

Specific Energy, Wh/kg

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100

1000

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20 100 120 140 160 180 200 220 240

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Li-ion

Vehicle Mobility

FCS Weapons

Emergency Aircraft

Pb Acid Spiral

Wound

Li-Polymer

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Aircraft

0 40 60 80

Commercial Hybrids

SLI

Where we are today

Where we need to go

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New chemistries

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Cell potential

© TISS, Stretton© pinkmonkey.com

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Cell capacity

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mol

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Cell energy

• Capacity x voltage

• Cut off voltage is controlling available energy but also limiting access for safe operation

Overcharge

Overdischarge

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Lithium ion battery principle

Li+ + e- + MeO2 → LiMeO2 LiC6 → Li+ + e- + C6

Dischargereaction:

Cathode Anode

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• D. Howell, Energy Storage Research and Development, Annual Progress Report 2006

• FreedomCAR and Fuel Partnership and United States Advanced Battery Consortium, Electrochemical Energy Storage Technical Team Technology Development Roadmap (Southfield, MI: USCAR, 2006).

Hybrid electricvehicles (HEV)

Plug-in Hybrid electricvehicles (PHEV)

Development targets and accomplishments

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Fruit battery – Natural galvanic element

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Have fun and stay safe!