Battery Technology Cheryl Salmonson 10/6/14

Applications using Batteries

Battery Convert stored chemical energy into electrical energy Reaction between chemicals take place Consisting of electrochemical cells Contains Electrodes Electrolyte

Electrodes and Electrolytes Cathode Positive terminal Chemical reduction occurs (gain electrons) Anode Negative terminal Chemical oxidation occurs (lose electrons) Electrolytes allow: Separation of ionic transport and electrical transport Ions to move between electrodes and terminals Current to flow out of the battery to perform work Think of questions to ask the class Different kinds of batteries, chemistry behind them Why one type over another in various applications Biggest restrictions, thing that need improving

Battery Overview Battery has metal or plastic case Inside case are cathode, anode, electrolytes Separator creates barrier between cathode and anode Current collector brass pin in middle of cell conducts electricity to outside circuit

Primary Cell One use (non-rechargeable/disposable) Chemical reaction used, can not be reversed Used when long periods of storage are required Lower discharge rate than secondary batteries  Use: smoke detectors, flashlights, remote controls Electrochemical reactions are non-reversible materials in the electrodes are utilized, therefore cannot regenerate electricity

Alkaline Battery Alkaline batteries name came from the electrolyte in an alkane Anode: zinc powder form Cathode: manganese dioxide Electrolyte: potassium hydroxide The half-reactions are: Zn(s) + 2OH−(aq) → ZnO(s) + H2O(l) + 2e− [e° = -1.28 V] 2MnO2(s) + H2O(l) + 2e− → Mn2O3(s) + 2OH−(aq) [e° = 0.15 V] Overall reaction: Zn(s) + 2MnO2(s) → ZnO(s) + Mn2O3(s) [e° = 1.43 V]

Zinc-Carbon Battery Anode: zinc metal body (Zn) Cathode: manganese dioxide (MnO2) Electrolyte: paste of zinc chloride and ammonium chloride dissolved in water The half-reactions are: Zn(s) → Zn2+(aq) + 2e- [e° = -0.763 V] 2NH4+(aq) + 2MnO2(s) + 2e-  → Mn2O3(s) + H2O(l) + 2NH3(aq) + 2Cl- [e° = 0.50 V] Overall reaction: Zn(s) + 2MnO2(s) + 2NH4Cl(aq) → Mn2O3(s) + Zn(NH3)2Cl2 (aq) + H2O(l) [e° = 1.3 V]

Primary Cell Alkaline Battery Zinc-Carbon Battery Zinc powered, basic electrolyte Higher energy density Functioning with a more stable chemistry Shelf-life: 8 years because of zinc powder Long lifetime both on the shelf and better performance Can power all devices high and low drains Use: Digital camera, game console, remotes Zinc body, acidic electrolyte Case is part of the anode Zinc casing slowly eaten away by the acidic electrolyte Cheaper then Alkaline Shelf-life: 1-3 years because of metal body Intended for low-drain devices Use: Kid toys, radios, alarm clocks

Secondary Cells Rechargeable batteries Reaction can be readily reversed Similar to primary cells except redox reaction can be reversed Recharging: Electrodes undergo the opposite process than discharging Cathode is oxidized and produces electrons Electrons absorbed by anode

Nickel-Cadmium Battery Anode: Cadmium hydroxide, Cd(OH)2 Cathode: Nickel hydroxide, Ni(OH)2 Electrolyte: Potassium hydroxide, KOH The half-reactions are: Cd+2OH- → Cd(OH)2+2e- 2NiO(OH)+Cd+2e- →2Ni(OH)2+2OH- Overall reaction: 2NiO(OH) + Cd+2H2O→2Ni(OH)2+Cd(OH)2

Nickel-Cadmium Battery Maintain a steady voltage of 1.2v per cell until completely depleted Have ability to deliver full power output until end of cycle Have consistent powerful delivery throughout the entire application Very low internal resistance Lower voltage per cell http://www.batterystuff.com/kb/articles/battery-articles/what-the-heck-is-a-nicd-battery.html http://www.ehow.com/list_6943868_uses-nickel-cadmium-battery.html http://www.puremobile.com/cell-phone-batteries

Nickel-Cadmium Battery Advantages: This chemistry is reliable Operate in a range of temperatures Tolerates abuse well and performs well after long periods of storage Disadvantages: It is three to five times more expensive than lead-acid Its materials are toxic and the recycling infrastructure for larger nickel- cadmium batteries is very limited

Lead-Acid Battery Anode: Porous lead Cathode: Lead-dioxide Electrolyte: Sulfuric acid, 6 molar H2SO4 Discharging (+) electrode: PbO2(s) + 4H+(aq) + SO42-(aq) + 2e- → PbSO4(s) + 2H2O(l)  (-) electrode: Pb(s) + SO42-(aq) → PbSO4(s) + 2e-  During charging  (+) electrode: PbSO4(s) + 2H2O(l) → PbO2(s) + 4H+(aq) + SO42-(aq) + 2e-  (-) electrode: PbSO4(s) + 2e- → Pb(s) + SO42-(aq)

Lead-Acid Battery The lead-acid cells in automobile batteries are wet cells Deliver short burst of high power, to start the engine Battery supplies power to the starter and ignition system to start the engine Battery acts as a voltage stabilizer in the electrical system Supplies the extra power necessary when the vehicle's electrical load exceeds the supply from the charging system

Lead-Acid Battery Advantages: Disadvantages: Batteries of all shapes and sizes, available in Maintenance-free products and mass-produced Best value for power and energy per kilowatt-hour Have the longest life cycle and a large environmental advantage Ninety-seven percent of the lead is recycled and reused in new batteries Disadvantages: Lead is heavier compared to alternative elements Certain efficiencies in current conductors and other advances continue to improve on the power density of a lead-acid battery's design

Lithium-Ion Battery Anode: Graphite Cathode: Lithium manganese dioxide Electrolyte: mixture of lithium salts Lithium ion battery half cell reactions CoO2 + Li+ + e- ↔ LiCoO2 Eº = 1V Li+ + C6+ e- ↔ LiC6 Eº ~ -3V Overall reaction during discharge CoO2 + LiC6 ↔ LiCoO2 + C6 Eoc = E+ - E- = 1 - (-3.01) = 4V

Lithium-Ion Battery Ideal material Low density, lithium is light High reduction potential Largest energy density for weight Li-based cells are most compact ways of storing electrical energy Lower in energy density than lithium metal, lithium-ion is safe Energy density is twice of the standard nickel-cadmium  No memory and no scheduled cycling is required to prolong battery life  http://batteryuniversity.com/learn/article/is_lithium_ion_the_ideal_battery

Lithium-Ion Battery Advantages: Disadvantages: It has a high specific energy (number of hours of operation for a given weight) Huge success for mobile applications such as phones and notebook computers Disadvantages: Cost differential Not as apparent with small batteries (phones and computers) Automotive batteries are larger, cost becomes more significant Cell temperature is monitored to prevent temperature extremes No established system for recycling large lithium-ion batteries

Intro to Tesla Motors Produces and Sells Electric Cars Founded: 2003 Headquarters: Palo Alto, California Servers: US, Canada, Western Europe, Middle East, China, Japan, Australia, New Zealand Model S $71K - $94K, Model X available in 2015 6000 employees Cars built in Fremont, CA (San Francisco suburb) 35,000 units expected to sell globally in 2014

Lithium Rechargeable Batteries and Tesla High energy density - potential for yet higher capacities Relatively low self-discharge, less than half of nickel-based batteries Low Maintenance No periodic discharge needed No memory Energy density of lithium-ion is three times of the standard lead acid Cost of battery Almost twice of standard nickel-cadmium (40%) Five times that of the standard lead acid

Tesla Model S The 85 kWh battery pack contains 7,104 lithium-ion battery cells 16 modules wired in series 14 in the flat section and 2 stacked on the front Each module has six groups of 74 cells wired in parallel The six groups are then wired in series within the module How many AA batteries does it at take to power the Model S ~35,417 Weigh approximately 320 kg 8 year infinite mile warranty on battery 350 to 400 VDC at ~200A Supercharging Station 110 VAC or 240 VAC charging voltages http://www.teslamotors.com/goelectric#charging Battery energy can store to the equivalent number of gallons gas (energy) – do math on board

Tesla’s New Gigafactory Opens 2017, Reno, Nevada Employ up to 6,500 people and pay ~ $25/hr Builds lithium-ion batteries Cost to build Gigafactory $5 Billion Nevada pitching in $1+ Billion in incentives $100 billion economic benefit over 20 years Factory will help Tesla move closer to mass producing $35,000 car with 200 mile range https://www.google.com/search?hl=en&source=hp&q=tesla+battery+plant&gbv=2&oq=tesla+battery+plant&gs_l=heirloom-hp.3..0l10.2215.7020.0.7239.19.11.0.8.8.0.172.1607.0j11.11.0....0...1ac.1.34.heirloom-hp..0.19.1748.N662h2U6vmg http://www.teslamotors.com/charging#/calculator So this is an awesome project…. But to truly appreciate the project we have to understand the science behind it

Conclusion Companies or researchers are improving batteries Reduced charging time Increase amount of energy stored for size and weight Increase life span, number of charges Reduce Cost Any predictions on where we might be in the future vs today? Toyota’s goal 4X today battery energy density, and 600 mile range for 2020 What cars, like Tesla, might be able to do in the future? Higher performance cars Faster re-charge time Increased mileage range on a charge Higher convenience level, similar to gas powered cars, more affordable