Battery to promote the modern life, from smart phones to electric cars, many technology devices are inseparable from the battery, like our solar powered portable generator. But the battery is how to store electricity? Why do they always take long? In a number of Samsung cell phone battery explosion, people are faced with a new problem: why the battery explosion? How to make the battery more durable? safer?
It's no exaggeration to say that battery life is an "explosive" problem, and Samsung has discovered this sad fact through painful lessons. Samsung GalaxyNote7 phone just listed because the battery life far more than its competitors and much praise. Unfortunately, good times do not last long. The global GalaxyNote7 battery explosion occurred in succession. Samsung was forced to recall the failed model and launched a replacement program, but the replacement of the new phone also began to explode, forcing Samsung to stop production.
This event is just a roadblock to the latest encounter on the long road to improving the performance of electronic devices batteries. Processor performance is rapidly increasing, doubling every 18 months, but the battery capacity with nearly 10 years to achieve the same progress. This huge gap began to lead to problems, Samsung's lessons once again that this is a difficult technical challenges to overcome.
Smartphone batteries are usually not enough to support a day of use, the laptop can only be used continuously for a few hours, electric cars are fully charged after the mileage is difficult to break 350 miles (about 563 km). So, why is the battery capacity is still such a thorny problem, when we can overcome it?
The structure and principle of the battery
A battery is like a small container of chemical energy. When a smartphone is plugged into a power source, the current causes a chemical reaction in the cell, causing electrons to flow from the negative to the positive.
When the charge is complete, the battery pushes the electrons through the circuit (in this case, the smartphone) to the negative side until all the electrons in the battery return to the negative or until the built-in switch turns off the power.
A typical cell typically contains a negative, positive, and electrolyte - a medium through which positive ions circulate.
Lithium-ion batteries used in most smart phones and electronic devices contain a metal oxide cathode made of a mixture of cobalt, nickel, manganese or iron, a porous graphite anode containing lithium ions inside, and lithium salt electrolytes. The batteries could be used in portable solar power generator.
The positively charged lithium ions flow from the negative electrode through the electrolyte to the positive electrode, driving the electrons through the smart phone and back to the negative electrode.
Why the battery is not durable
The principle of the battery may be very simple, but the technology is very complex. The biggest limitation of batteries is their energy density.
How much energy a cell can produce depends on how much of its chemical components store energy. The inactive material inside the battery is a burden, including the housing, the control chip, and the cables that deliver the current - they can only add weight and not increase energy.
Typical smart phone lithium-ion battery energy density of about 150 watt hour / kg (Wh / kg). Since 1990, since the birth of lithium-ion battery energy density has been improved, but still subject to structural and chemical constraints. The lithium-ion batteries include lifepo4 batteries, it could be used in portable solar power generator.
Relying on existing technology, the only way to quickly increase smart battery life is to increase the energy efficiency of smartphone electronics or to increase the size of the battery, while slimmer smartphones require slimmer batteries.
Battery life is not constant over the life of a smartphone, and as time goes on and the battery is repeatedly charged and discharged, battery life becomes shorter and shorter.
This is because the chemical reaction that produces the current causes a thin layer of lithium to deposit on the electrode, resulting in a reduction in the amount of lithium ions that can be used to generate the current and to increase the internal resistance of the battery.
The higher the resistance, the more difficult it is for the battery to maintain an effective voltage, thus reducing the power output after each charge. You may remember the relevant formula learned in secondary school:
Voltage = Current x Resistance (V = IR)
