Today, batteries are almost everywhere in our daily lives. It can be said that the battery is a great invention in the development of human society. It not only has a wonderful and long history, but also has the same awkward future.
Essentially, a battery is a device that converts stored chemical energy into electrical energy. Basically, a battery is a small chemical reactor that produces high-energy electrons by reaction and injects it into an external device.
Past and present
The early appearance of the battery exceeded our imagination. In 1938, the head of the Baghdad Museum found the original battery now known as the "Baghdad battery" in the basement of the museum. Analysis shows that the original battery can be traced back to 250 BC, belonging to the creation of the Mesopotamian civilization.
This earliest battery caused a lot of controversy. There are many opinions about its use, and possible hypotheses include electroplating, pain relief, or the tingling sensation that people experience when they come into contact with them to create a religious experience.
The American inventor Benjamin Franklin first used the term "Battery" in 1749. At the time he used a series of capacitors in series for electrical experiments.
The true modern battery was invented in 1800 by the Italian physicist Alessandro Volt. He built a small unit by sandwiching a sheet of salt-impregnated cloth between a piece of copper and a piece of zinc, and then stacking the small units to get a "volt". The wires connect the two ends of the stack to produce a stable current. Each small unit is capable of producing an open circuit voltage of 0.76 volts. By connecting these small cells in series, we can get a voltage equivalent to the sum of the voltages of each small cell.
Lead storage batteries are among the most enduring batteries currently known. They were invented in 1859 and are still used in most internal combustion engine vehicles. It is also the first rechargeable battery.
Today, the size of the battery can be as large as megawatts, used to store the power of the solar power station to ensure a stable energy supply in the region; small to button size, to power the electronic watch you wear.
Different batteries are based on different chemical reactions, which also allows each different cell to have a different open circuit voltage, typically between 1.0 and 3.6 volts. By connecting these small cells in series, we can increase the voltage; while paralleling these small cells can enhance the current. This rule is used by us to increase the voltage and current to provide the current and voltage we need. Even for megawatt batteries, its voltage and current are obtained through this most basic law.
It is predicted that battery technology will once again usher in a leap. The new battery model will be able to get enough energy from home solar and wind energy installations and have enough capacity to store it, providing the entire family with the power needed for the next few days at the right time (usually at night).
How does the battery work?
Inside the battery, when the chemical reaction begins, additional electrons are released and the battery begins to discharge. The process of extra electron release is like the process of iron oxidation and rust, which reacts with oxygen to release electrons to oxygen to form iron oxides.
The standard battery construction is to separate two metals or compounds of different chemical potentials with a layer of porous insulator. The chemical potential is the energy stored between the atom and the chemical bond. When the electron is free to move in the external device connected to it, the energy can be transmitted to those moving electrons.
Conductive liquids such as brine are often used to transport soluble ions. During the reaction, these ions can be transferred from the surface of one metal to the surface of another metal. We usually call such a conductive liquid an electrolyte. .
During discharge, a metal or compound that loses electrons is called an anode, and a metal or compound that gets electrons is called a cathode. In the external circuit, the flow of electrons flows from the anode to the cathode, which is the "current" we use to drive electrical equipment.
Once with charging
After the current is generated, the state of some batteries cannot be reversed. We call this battery a primary battery. When one of the reactants is exhausted, the battery can no longer be used.
The most common primary battery is a carbon zinc battery. If the electrolyte is alkaline, the battery can be more durable. This is the alkaline battery we usually buy at the supermarket.
The difficulty with handling a battery is that we cannot recycle these batteries by recharging. In today's large-scale battery, recycling is becoming more and more important, and frequent battery replacement is not commercially viable.
One of the world's first rechargeable batteries, nickel-cadmium batteries, also uses alkaline electrolytes. In 1989, nickel-hydrogen batteries were invented, and they have a longer life than nickel-cadmium batteries.
This type of battery is very sensitive to excessive overheating, so the charging power should be controlled below a ** power. But a well-designed controller can speed up the charging process, and we no longer have to wait a few hours for charging.
Now, applications like mobile phones and laptops have been pursuing the goal of storing as much energy as possible in as small a space as possible. As the energy per unit volume increases, the risk of sudden discharge increases, but we can also find some ways to deal with it. For example, for a mobile phone battery, because it is relatively small, we can increase its safety by adding a current limiter to the battery.
However, as more and more large-scale batteries are put into use, people will pay more and more attention to the safety of these large and large-sized batteries.
**Leap: Lithium-ion battery
Today, most new technologies require batteries to have a more compact design, more power, better safety, and the need for batteries to be recharged.
In the year, American physics professor John Goodinav invented a new type of lithium battery. In such a lithium battery, lithium can be shuttled between the two electrodes in the form of lithium ions in the battery.
Lithium is one of the lightest elements in the periodic table and has a strong electrochemical potential. These two advantages make it possible to provide ** voltage in a minimum volume.
And this is the basis of lithium-ion batteries. In this new battery, a compound of lithium and a transition metal such as cobalt, nickel, manganese, and iron is used as a cathode. After the application of the voltage, recharging begins and the positively charged lithium ions migrate from the cathode to the anode made of graphite material and become metal lithium again.
Because metallic lithium has a strong electrochemical driving force, metallic lithium is easily oxidized, it migrates to the cathode and becomes lithium ions again, and the outer electrons are transferred to transition metal ions (such as cobalt ions). The electron movement in this cycle gives us the current we need.
Second leap: nanotechnology
Due to the addition of transition metals, lithium ions can provide higher energy per small unit, but the increase in reactivity also has a negative effect, and the battery is more susceptible to a phenomenon known as "heat dissipation".
In the 1990s, Sony produced a lithium cobalt oxide battery (this is also a commercial lithium-ion battery), but the serious "thermal runaway" caused many of this type of battery to catch fire. If the problem cannot be solved, then in order to obtain better reactivity, the idea of ​​using nanomaterials to make the battery cathode is impossible to talk about.
Still, Gudinaf introduced a new lithium-ion battery cathode made of lithium, iron and phosphate. This stable electrode is another big leap in battery technology.
Along with the continuous development of new batteries, many new applications have emerged. From power tools to hybrid and pure electric vehicles, we are able to find the shadow of lithium-ion batteries. Perhaps the most important application in the future will be to provide household electricity for the home.
electric car
In the field of electric vehicles, the leader is undoubtedly Tesla. The company plans to build the super battery factory Gigafactory to produce large batteries suitable for use in pure electric vehicles. The lithium battery pack capacity of the company's S-type car equipment has reached an astonishing 85 kWh.
This battery pack capacity is enough for an ordinary family, and because of this, everyone has more expectations for the new product, the home battery powerwall, released by Elon Musk.
Modularity in battery design may create a new, interactive battery model that can be used both in a car and in a home life without having to redesign and build.
Perhaps we are the witnesses of an era. In this era, energy is once again being upgraded, and the large battery for the future that provides us with energy is constantly upgraded from the original small battery.
