C h a n g e t h e Wo r l d o n e i d e a a t a t i m e Andrew Lamb November 9 th , 2015
Magefekt ● Product Sales ● Engineering Consultancy ● www.magefekt.com
Tonight Think differently ● Batteries are a store of amp hours ● Most tasks require amps not Volts ● Think of the user’s needs not the Battery Data Sheet ● Make it safe ● Make it reliable
What is a Battery ? ● A battery is a chemical cell containing an electrolyte with two distinct chemical potentials. The portion of each potential is determined by the ingress and egress of current. ● The recoverable amp hours multiplied by the potential (i.e.Volts) can be used to deliver energy.
What is Voltage ● Voltage is the activation threshold within a solid state device. Examples: ● Voltage is the activation energy within an LED. ● The top speed of an electric motor ● The break down voltage of a device.
Energy Density A battery car has the energy ● capacity of a Soft Drink Can of petrol.
Energy Density
Discharge / Energy Density In an electric drive ● application Voltage limits the speed of a motor. As the voltage drops ● the top speed will drop. Operational speed ● during normal use therefore determines Voltage required.
Charge / Discharge Cycle Lithium Batteries ● have a smaller drop in Voltage during an operational cycle than lead.
Energy Density Given that energy is ● the area under the charge discharge curve then the energy between the curves is lost when the higher voltage is not required.
Why is this important ? ● The only thing that is fixed in the operational cycle of a Battery is the Amp Hours in and out. ● Current is the torque that gets you up the hill. ● Current is what is converted to light in LED’s ● Current is what comes out of a solar panel.
Practical Application The client wanted to ● increase the range of their high dependency chairs from 10km to 30km at 10km/h . Magefekt achieved 40km ● at 10 km/h with 60% reduction of the original battery weight and half the size.
Motor Vehicles Family and Tow 14+ lt/100 Family 3.5+ lt/100 Daily Commuter Below 3 lt/100
Private vehicle needs Family and Tow ● Takes the Family, luggage and tows as far as you ● want to go Mitsubishi Challenger 10 to 14 lt/100km ● Family ● Takes the Family ● I use a Toyota Prius 3.6 to 5 lt/100km ● Commuter ● Takes 1.1 occupants ● Idea’s Live Here ●
What is the market? There are 3 000 000 Suburban Households ● More than one Car ● Work commute is under 40km. ● Rush hour has a vehicle occupancy of 1.1 ● The Commuter Car is the solution to public ● transport where the Train Stations are not an option. The Commuter Car Market is larger than the ● Domestic Vehicle Production in the last 10 years
Domestic The question is what do we need ● Domestic demand can be counter cyclical to solar power ● generation. It is therefore important to minimize the domestic consumption ● and move the load to align with power availability. Temperature management (air conditioning), washing ● machines and dishwashers should be used during peak solar generation times. Excess solar power generated can be stored in batteries for ● night use. Unlike Lead, Lithium has excellent storage characteristics such as: fast charging, high discharge capability and long life
• Solar installation pumping sewage at Rye. The system is independent with Grid Backup for battery charging. Battery assembly consists of 2 x Adverse Environment 74 Ah 24V units. The system is monitored remotely and expected to have 10 year service intervals.
Magefekt is looking at safety ● This is then being used in our design and sourcing of batteries. Magefekt has collected over 600 failed and end of ● life Lithium Batteries We are progressively analyzing their failure modes ● We are collecting the data and pushing to reduce the ● failure of batteries
Safety ● Whilst LiFePO4 is not the highest capacity cells, the thermal runaway of 270C makes it the least likely to cause issues. ● Magefekt design considers eddy current prevention, thermal management and integrated fusing to reduce the likelihood of thermal runaway from a short.
Consequence & Mechanism The Aurora Solar Car caught ● fire in Spain. The battery pack was ● managed by total voltage over 40 parallel modules. An open circuit failure at low ● voltage within the module was not visible within data resolution. Consequently an overcharge ● failure is the most likely cause.
Open circuit failures Incorrect setting, poor process ● control or Contamination can lead to joint failure. Tabs are folded up so loads will pull on Welds A single cell was found in the ● cycling of an Aurora Pack. This lead to bench top simulations showing that an over charge on a warm day will cause a thermal incident.
Short Circuit through membrane Trim debris is carried ● through the process and contaminates plates and membranes Under mechanical ● pressure and the membrane is damaged and eventually shorts
Magefekt Choice LiFePO 4 cathode, graphite anode L i t h i u m I r o n P h o s p h a t e : LFP or Li-phosphate Voltage, nominal 3.20V, 3.30V Specific energy (capacity) 90–120Wh/kg Charge (C-rate) 1C typical, charges to 3.65V; 3h charge time typical 1C, 25C on some cells; 40A pulse (2s); 2.50V cut-off (lower that Discharge (C-rate) 2V causes damage) Cycle life 1000–3000 (related to depth of discharge, temperature) Thermal runaway 270°C (518°F) Very safe battery even if fully charged Portable and stationary needing high load currents and Applications endurance Very flat voltage discharge curve but low capacity. One of safest Comments Li-Ions. Used for special markets. Elevated self-discharge.
Reliable ● Magefekt goes back to the basics Why do batteries fail. ● Design defect ● Quiescent current through Battery management ● systems Battery Management system failures ● Membrane Defects ● Water Ingress ● Poor manufacturing ● Poor application ●
Size ● Bigger is not better Lithium batteries are reliant on diffusion ● membranes. Membranes defects are described in terms of ● defects per square meter. The more area of membrane in a cell the larger ● the likelihood of a defect being in the cell.
Packaging Prismatic ● Plastic ● Polymers are water absorbent by nature, Nylon 3% and Acetal 0.3%. ● This allows water to pass through the packaging to react with the lithium, ● distorting the graphite resulting in swelling Steel ● Steel offers resistance to water ingress but use of valves negates the ● advantages and flat side offers no resistance to swelling. Satchels ● Satchels have no structural support and whilst metalized still allow ● water ingress
Packaging ● 18650 18650 offers the structural integrity of a steel can ● and cylindrical structure. In a nail test the penetrator is deflected. ● 26650 The 26650 has all the advantages of the 18650 ● with a higher capacity. Carefully selected supply of 26650 cells underlies the magefekt product range.
High Performance Packs The LiPo shown was designed ● for high energy density, low heat and medium life. Each parallel section was ● monitored through opto coupling to isolate voltages. The pack was left in the factory ● overnight, condensation formed on the packaging, ingressed and reacted.
What have I not talked about ● Magefekt Batteries No charge shelf life of two years ● First balance at two years ● Run Cold ● Impact Resistant ● High rate of thermal diffusion ● Submersible in adverse environments ● Capacity of 80% at 3000 cycles ●
Thank you Thank you Ma Ma g g e e f f e e k k t t T T e e a a m m
Why Electric Each time we fill the car around ● 60c per liter leaves Australia. Reducing Fuel consumption ● reduces the national debt. If three million cars Saved 3.2 Lt ● per day we would save $5.7. Localize and minimize the ● energy.
Trust the Maths If the model does not ● match your data then find out why. Load and systems are ● balanced .
LiNiMnCoO 2 . cathode, graphite anode L i t h i u m N i c k e l Ma n g a n e s e C o b a l t O x i d e : NMC (NCM, CMN, CNM, MNC, MCN similar with different metal combinations) Voltage, nominal 3.60V, 3.70V Specific energy (capacity) 150–220Wh/kg 0.7–1C, charges to 4.20V, some go to 4.30V; 3h charge typical. Charge (C-rate) Charge current above 1C shortens battery life. Discharge (C-rate) 1C; 2C possible on some cells; 2.50V cut-off Cycle life 1000–2000 (related to depth of discharge, temperature) Thermal runaway 210°C (410°F) typical. High charge promotes thermal runaway Applications E-bikes, medical devices, EVs, industrial Provides high capacity and high power. Serves as Hybrid Cell. Comments Favorite chemistry for many uses; market share is increasing.
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