How does the phone battery work and why can it explode?

The battery provides fuel for modern life, from smartphones to electric cars. But how does the battery store power? Why can't their lifespan last? Just like why can they explode?

According to The Guardian, battery life is the cause of explosion . At some level, Samsung has found the key to making the company have to exploit Note 7 as it is today. Although when launched, Samsung Galaxy Note 7 has always been praised as one of the smartphones with the best battery life of the high-end segment, far ahead of the iPhone 6s and 7 Plus. However, the Note 7 battery exploded, forcing Samsung to issue a recall order with the pay-back program, but the second replacement machines continued to explode, causing the company to stop producing the Note 7 permanently.

This incident marked a new step in the improvement of batteries for electronic devices. If the processing speed is doubled after about 18 months, then the battery capacity must take nearly a decade to be like that. It was this gap that started to cause problems, even if Samsung had to pay for it, there was no way to fix it.

Usually the battery of a smartphone can be used for a day, with a laptop a few hours, and with an electric car is about 350 miles away. So why is the battery so complex and when can we fix it?

What is the battery?

The battery is a small container containing chemical energy.

The battery is a small container containing chemical energy. When charging the device, electricity is used to establish chemical reactions, transporting electrons from a negatively charged anode to a positively charged cathode at the end of the battery.

Each time the battery is charged, the battery can generate electricity by making electrons run through an electrical circuit, in this case a smartphone, they will go to the anode and keep doing so until the entire electron has In the battery, it all converts towards the positive side or towards the integrated battery to disconnect the battery.

What is the battery made of?

Each battery has anode, cathode and solvent - a substance that helps positive ions to move inside the battery.

Li-ion batteries are batteries used in phones and electronic devices that have cathode poles (cathodes) made of metal oxide, mainly cobalt, nickel, manganese or iron mixed with an anode electrode (anode ) contains tiny holes, made of graphite, inside with lithium ion and electrolyte, lithium salt.

The positively charged lithium ions are exchanged inside the solvent from the anode to the cathode to bring the electrons into the smartphone when necessary and then return to the anode.

Why doesn't Li-ion battery last for long?

Each Li-ion battery inside the smartphone contains about 150Wh / kg.

The structure of each battery can be simple, but the chemicals and technology that make them work are not simple. The density of energy (energy density) is the biggest factor, limiting the current Li-ion battery.

To generate electricity, Li-ion batteries will rely on chemical components that accumulate energy within them. Shells, control chips, and wires in addition to increasing the battery weight do not create any additional energy.

Energy density is usually calculated in Wh / kg and each Li-ion battery inside the smartphone contains about 150 Wh / kg. This is a great improvement effort since the battery was introduced in the early 1990s, though still using the same formula and chemical properties as before.

The only way to increase battery life today is to increase the energy efficiency of each electronic device and increase the size of the battery. But, as the smartphone gets thinner and thinner, the battery must be thinner and lighter.

Why is battery or bottle hot?

The higher the resistance, the more difficult it is for the battery to maintain a certain voltage level.

When the battery is constantly charging and discharging, it means that the battery life will decrease over time, it cannot be forever "immortal" .

This is because electrical reactions that produce electricity thinning the lithium layer placed on each electrode, reduce the number of ions that generate electricity while increasing the internal resistance of each battery.

The higher the resistance, the more difficult it is for the battery to maintain a certain voltage, so the power will gradually decrease after each charge.

What causes some batteries to explode?

Conventional batteries will have a higher energy density than Li-ion batteries, but they are not safe to use for portable electronic devices.

The more energy is placed in a box, the more dangerous it will be.

"The more energy is placed in a box, the more danger will be," said Dr. Billy Wu, an instructor at Imperial College London, "Safety is the most important thing, especially the management issue. If the battery heats up to 80 degrees Celsius, you must cool them down so that the components don't decompose, preventing them from exploding. "

What happens next?

In the short term, battery advances will bring Li-ion technology closer to its limited theories to increase the energy density of batteries.

Need to optimize the internal structure of each battery.

Traditional Li-ion batteries all use manganese oxide with a theoretical capacity of 280Wh / kg but the actual product only reaches 150Wh / kg, so there will definitely be many improvements in the future.

"Need to optimize the internal structure of each battery," Dr. Wu said. "If you look inside the battery you can see the whole hollow structure for the active material."

"If the output power is higher, you need a more hollow structure to increase the surface area and allow lithium ions to travel from one place to another at any time, but therefore it will make the battery available. more holes, the ability to keep active materials becomes worse, making battery capacity less and less ".

Some more advanced chemical batteries such as lithium-sulpur batteries and lithium-silicon batteries are still being developed by companies. Hope to have commercial products soon in the coming years.

What is the future of battery technology?

The Samsung Note 7 image exploded when using pressure equal to the pressure of a fully charged battery in a battery-operated laboratory at Applied Energy Hub in Singapore on October 6.

Solid-state batteries can be used in the future when liquid electrolytes replaced with solid form will provide significant safety for users.

"The main advantage of solid-state batteries is that you can use lithium as a kind of anode pole to produce more energy and energy density, but not safe with liquid electrolytes , " Wu explained.

The solid battery will remove empty carbon anode particles, thereby reducing the weight for the battery to create more power.

Metal batteries, using zinc, lithium or aluminum, are still far away but will be commercialized over the next 20 years, Dr. Wu said.

What to do to extend battery life?

Another point, never plug in the battery constantly, especially with a laptop.

Some of the following can help you extend your battery life. Because the chemical reactions inside each battery will be optimized when the battery is charged below 20% and above 80%.

If you keep the Li-ion battery in this range, it will last longer. Another point, never plug in the battery constantly, especially with a laptop. Sometimes you should remove the battery and plug in the charger directly. One month should be done once.