question: How does fast(Flash?)charge work? What is limiting us to charge our phone/electronics to be fully charged in minutes?
comment: A few reasons why fast charging is difficult. 1. Heat generation in the battery . No charging process is 100% efficient, they all make heat (except flow batteries which charge by replacing the electrolyte). 2. For lithium cells, overvoltage damages cells. In order to make higher current flow, a higher voltage is needed. Lithium cells are damaged by voltage over 4.3V. Their chargers use a constant current at first which can be fast, but once the voltage reaches 4.3V they have to stay at 4.3V for the rest of the charge. The current then declines as the cell reaches full charge. This is why 0-70% is faster than 70-100%. Tldr : you can't fast charge beyond around 70%. 3. Fast charging requires more current which needs either thicker wire or higher voltage along with conversion circuitry. 120W at 4 V is 30A. That is not possible in a thin wire or small connector. Existing USB uses higher voltage to limit current. The phones have conversion circuitry but scaling that up to 120W takes space and dissipates heat.
passages: Quick Charge was announce in 2012 and has more faster technology in 2016 using USB-C and USB-PD connector. It can charge mobile phone 4 times faster than standard micro USB.
  
  Section::::Applications.:Stationary battery plants.
   Quick Charge is a proprietary technology which allows for the charging of battery powered devices, primarily mobile phones, at levels above and beyond the typical 5 volts and 2 amps for which most USB standards allow. Numerous other companies have their own competing technologies; these include Mediatek's Pump Express, OPPO's VOOC (licensed to OnePlus as Dash Charge). To take advantage of Qualcomm Quick Charge, both the host providing power and the device must support it. In 2012 the USB Implementers Forum (USB IF) announced that their USB Power Delivery (USB PD) standard had been finalized which allows for devices to transfer up to 100 watts of power over capable USB ports. This new technology was first seen in a Xiaomi Mi Mix 3 prototype that went from 1% to 100% in a mere 17 minutes.
   Chargers take from a few minutes to several hours to charge a battery. Slow "dumb" chargers without voltage or temperature-sensing capabilities will charge at a low rate, typically taking 14 hours or more to reach a full charge. Rapid chargers can typically charge cells in two to five hours, depending on the model, with the fastest taking as little as fifteen minutes. Fast chargers must have multiple ways of detecting when a cell reaches full charge (change in terminal voltage, temperature, etc.) to stop charging before harmful overcharging or overheating occurs. The fastest chargers often incorporate cooling fans to keep the cells from overheating. Battery packs intended for rapid charging may include a temperature sensor that the charger uses to protect the pack; the sensor will have one or more additional electrical contacts.
   The charging time depends on the battery capacity and the charging power. In simple terms, the time rate of charge depends on the charging level used, and the charging level depends on the voltage handling of the batteries and charger electronics in the car. The US based SAE International defines Level 1 (household 120V AC) as the slowest, Level 2 (upgraded household 240 VAC) in the middle and Level 3 (super charging, 480V DC or higher) as the fastest. Level 3 charge time can be as fast as 30 minutes for an 80% charge, although there has been serious industry competition about whose standard should be widely adopted. Charge time can be calculated using the formula: "Charging Time [h] = Battery Capacity [kWh] / Charging Power [kW]"
   Section::::Type.:Fast charger.
  
  Fast chargers make use of control circuitry to rapidly charge the batteries without damaging any of the cells in the battery. The control circuitry can be built into the battery (generally for each cell) or in the external charging unit, or split between both. Most such chargers have a cooling fan to help keep the temperature of the cells at safe levels. Most fast chargers are also capable of acting as standard overnight chargers if used with standard NiMH cells that do not have the special control circuitry.
  
  Section::::Type.:Three stage charger.
   The OPPO VOOC (Voltage Open Loop Multi-step Constant-Current Charging) Flash Charging system is a proprietary rapid-charge technology created by OPPO Electronics, which, at present, is able to charge certain OPPO devices from 0 to 75% in just 30 minutes. In contrast to Qualcomm's QuickCharge technology increasing the voltage during fast charging, VOOC uses a higher current than normal USB 2.0 charging. Thus, VOOC operates at 5V and 4A. The VOOC Flash Charge circuit technology reportedly lowers the temperature of the charging adapter, and creates an interface from the adapter to the phone, which improves the speed and safety of the charge.
   A 10 amp-hour battery could take 15 hours to reach a fully charged state from a fully discharged condition with a 1 amp charger as it would require roughly 1.5 times the battery's capacity.
  
  Public EV charging stations provide 6 kW (host power of 208 to 240 VAC off a 40 amp circuit). 6 kW will recharge an EV roughly 6 times faster than 1 kW overnight charging.
  
  Rapid charging results in even faster recharge times and is limited only by available AC power, battery type, and the type of charging system.
   BULLET::::- Capacity in mAh: mAh stands for milli Ampere-hour and measures the amount of power flow that can be supplied by a certain power bank at a specific voltage. Many manufacturers rate their products at 3.7 V, the voltage of cell(s) inside. Since USB outputs at 5 V, calculations at this voltage will yield a lower mAh number. For example, a battery pack advertised with a 3000 mAh capacity (at 3.7 V) will produce 2220 mAh at 5 V. Power losses due to efficiency of the charging circuitry also occur.
   , lithium iron phosphate () battery technology was the fastest-charging/discharging, fully discharging in 10–20 seconds.
   When a device doesn't recognize the faster-charging standard, generally the device and the charger fallback to the USB battery-charging standard of 5 V at 1.5 A (7.5 W).
  
  When a device detects it is plugged into a charger with a compatible faster-charging standard, the device pulls more current or the device tells the charger to increase the voltage or both to increase power (the details vary between standards).
  
  Such standards include:
  
  BULLET::::- Qualcomm Quick Charge
  
  BULLET::::- MediaTek Pump Express
  
  BULLET::::- Samsung Adaptive Fast Charging
  
  BULLET::::- Oppo Super VOOC Flash Charge, also called OnePlus Dash Charge
  
  BULLET::::- Huawei SuperCharge
   In June 2009, many of the world's largest mobile phone manufacturers signed an EC-sponsored Memorandum of Understanding (MoU), agreeing to make most data-enabled mobile phones marketed in the European Union compatible with a common External Power Supply (common EPS). The EU's common EPS specification (EN 62684:2010) references the USB Battery Charging Specification and is similar to the GSMA/OMTP and Chinese charging solutions. In January 2011, the International Electrotechnical Commission (IEC) released its version of the (EU's) common EPS standard as IEC 62684:2011.
  
  Section::::Power.:Faster-charging standards.
  
  A variety of (non-USB) standards support charging devices faster than the USB battery-charging standard (USB-#BCS).
   Quick Charge
  
  Quick Charge is a technology found in Qualcomm SoCs, used in devices such as mobile phones, for managing power delivered over USB. It offers more power and thus charges batteries in devices faster than standard USB rates allow. Quick Charge 2 onwards technology is primarily used for wall adaptors, but it is also implemented in car chargers and powerbanks (For both input and output power delivery). 
  
  Section::::Details.
   Some companies have been experimenting with battery swapping to eliminate delay while charging.A “Super Fast” charging location will currently charge most cars to around 80% in 45–50 minutes.  The final 20% – as with a mobile phone – takes longer, because the systems slow to safely fill the battery and avoid any risks.
  
  Section::::Batteries.:Charging.:Hybrid vehicles.
  
  Some electric vehicles have built in generators, these are considered a type of hybrid vehicle. 
  
  Section::::Batteries.:Lifespan.
   Slow battery chargers may take several hours to complete a charge. High-rate chargers may restore most capacity much faster, but high rate chargers can be more than some battery types can tolerate. Such batteries require active monitoring of the battery to protect it from overcharging. Electric vehicles ideally need high-rate chargers. For public access, installation of such chargers and the distribution support for them is an issue in the proposed adoption of electric cars.
  
  Section::::C-rate.
   BULLET::::3. Multiple bits can be stored on a single flash memory cell.
  
  BULLET::::4. Improved reliability
  
  BULLET::::5. Higher yield since the charge trap is less susceptible to point defects in the tunnel oxide layer
   In 2014, researchers at MIT, Sandia National Laboratories, Samsung Advanced Institute of Technology America and Lawrence Berkeley National Laboratory discovered that uniform charging could be used with increased charge speed to speed up battery charging. This discovery could also increase cycle durability to ten years. Traditionally slower charging prevented overheating, which shortens cycle durability. The researchers used a particle accelerator to learn that in conventional devices each increment of charge is absorbed by a single or a small number of particles until they are charged, then moves on. By distributing charge/discharge circuitry throughout the electrode, heating and degradation could be reduced while allowing much greater power density.
   Control Pilot (Current limit): The charging station can use the wave signal to describe the maximum current that is available via the charging station with the help of pulse width modulation: a 16% PWM is a 10 A maximum, a 25% PWM is a 16 A maximum, a 50% PWM is a 32 A maximum and a 90% PWM flags a fast charge option.
   In 2005, handheld device battery designs by Toshiba were claimed to be able to accept an 80% charge in as little as 60 seconds. Scaling this characteristic up to the same 7 kilowatt-hour EV pack would result in the need for a peak of 340 kilowatts of power from some source for those 60 seconds. It is not clear that such batteries will work directly in BEVs as heat build-up may make them unsafe.
  
  Section::::Specifics.:Charging.:Recharging time.
  
  Electric cars like Tesla Model S, Renault Zoe, BMW i3, etc. can recharge their batteries at quick charging stations within 30 minutes to 80 percent.
   Per the base specification, any device attached to a "standard downstream port" (SDP) must initially be a low-power device, with high-power mode contingent on later USB configuration by the host. Charging ports, however, can immediately supply between 0.5 and 1.5 A of current. The charging port must not apply current limiting below 0.5 A, and must not shut down below 1.5 A or before the voltage drops to 2 V.
   Battery charging and discharging rates are often discussed by referencing a "C" rate of current. The C rate is that which would theoretically fully charge or discharge the battery in one hour. For example, trickle charging might be performed at C/20 (or a "20 hour" rate), while typical charging and discharging may occur at C/2 (two hours for full capacity). The available capacity of electrochemical cells varies depending on the discharge rate. Some energy is lost in the internal resistance of cell components (plates, electrolyte, interconnections), and the rate of discharge is limited by the speed at which chemicals in the cell can move about. For lead-acid cells, the relationship between time and discharge rate is described by Peukert's law; a lead-acid cell that can no longer sustain a usable terminal voltage at a high current may still have usable capacity, if discharged at a much lower rate. Data sheets for rechargeable cells often list the discharge capacity on 8-hour or 20-hour or other stated time; cells for uninterruptible power supply systems may be rated at 15 minute discharge.
   With suitable power supplies, good battery lifespan is usually achieved at rates not exceeding "0.5"C"" or so, taking two to three hours for a full charge, but faster charging can be done.
  
  Charging time is often limited by the capacity of the grid connection. A normal household outlet delivers 1.5 kilowatts (in the US, Canada, Japan, and other countries with 110 volt supply) and 3 kilowatts (in countries with 230 V supply).
   In 2017, the first vehicle in the US to use the new Lithium Titanium Oxide (LTO) battery non-flammable battery technology is a scooter called The Expresso. This new technology charges a battery in less than 10 minutes and withstands 25,000 charges (the equivalent of 70 years of daily charges). The technology, created by Altairnano, is currently being used in China where over 10,000 urban buses run on these fast charge batteries.
  
  Section::::Power source.:Charging.
   The charging protocol (how much voltage or current for how long, and what to do when charging is complete, for instance) depends on the size and type of the battery being charged. Some battery types have high tolerance for overcharging (i.e., continued charging after the battery has been fully charged) and can be recharged by connection to a constant voltage source or a constant current source, depending on battery type. Simple chargers of this type must be manually disconnected at the end of the charge cycle, and some battery types absolutely require, or may use a timer, to cut off charging current at some fixed time, approximately when charging is complete. Other battery types cannot withstand over-charging, being damaged (reduced capacity, reduced lifetime), over heating or even exploding. 
   For models with DC fast charging, a battery pack can be charged from fully discharged to 80% capacity in about 30 minutes. Nissan warns that if fast charging is the primary way of recharging, then the normal and gradual battery capacity loss is about 10% more than regular 220-volt charging over a 10-year period. Other companies make compatible charging stations, and companies and local government have various initiatives to create networks of public charging stations.
  
  Section::::First generation (2010–2017).:Technology.
   As of 2016, the world's largest automated port, PSA TUAS, started to use the Microvast LpTO for 22 electric AGVs as a first phase of a project for horizontal container transportation.
  
  Section::::Brands and uses.:Toshiba.
  
  Toshiba released a lithium-titanate battery, dubbed "Super Charge Ion Battery" (SCiB). The battery is designed to offer 90% charge capacity in just 10 minutes.
  