Yes, lithium batteries are divided into lithium batteries and lithium ion batteries. Cell phones and laptops use lithium-ion batteries, commonly known as lithium batteries. However, true lithium batteries are rarely used in daily electronic products due to their high risk.
Lithium ion battery components
Steel shell/aluminum shell/cylindrical series/soft packaging:
(1) Positive electrode - the active material is generally lithium manganate or lithium cobalt oxide, lithium nickel cobalt manganate materials. Electric bicycles generally use lithium nickel cobalt manganate (commonly known as ternary) or ternary + a small amount of pure lithium manganate and lithium iron phosphate are large and gradually fade. due to poor performance or high cost. The collector ofThe current conductor uses electrolytic aluminum foil with a thickness of 10 to 20 microns.
(2) Separator - a specially formed polymer film with a microporous structure that allows lithium ions to pass freely, but electrons cannot pass through.
(3) Negative electrode - the active material is graphite, or carbon with a graphite structure, and the conductive current collector uses electrolytic copper foil with a thickness of 7 to 15 microns .
(4) Organic electrolyte - a carbonate solvent in which lithium hexafluorophosphate is dissolved. For polymers, a gel electrolyte is used.
(5) Battery casing - divided into steel casing (square type rarely used), aluminum casing, nickel-plated iron casing (used for cylindrical batteries), aluminum-plastic film (soft packaging) , etc. , as well as the batteries. The cap is also the positive terminals andnegative of the battery.
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Environmental pollution by lithium. The batteries are Co, which should be the positive electrode. Lithium cobalt oxide is used. Cobalt is ranked 27th in the periodic table, behind iron and before nickel. As a transition metal, it has some impact on the environment, but it is. insignificant.
Another thing is the electrolyte used in lithium batteries. The electrolyte is organic and has some impact on the environment. Generally speaking, lithium batteries have little impact on the environment.
To improve safety and voltage, scientists invented materials such as graphite and lithium cobalt oxide to store lithium atoms. The molecular structures of these materialsx form tiny nanoscale storage arrays, which can be used to store lithium atoms. This way, even if the battery shell breaks and oxygen enters, the oxygen molecules will be too large to enter these small storage compartments, so the lithium atoms will not enter contact with oxygen to avoid an explosion.
Detailed Information
After the lithium battery cell is overcharged to a voltage higher than
4.2V
, side effects will begin. The higher the overload voltage, the higher the risk. Once the voltage of the lithium battery
is greater than
4.2V
,
the number of lithium atoms remaining in the positive electrode material is less than half
At this time, the storage cells often collapse,
leaving the capacity of the battery decreases slightlypersistence.
If charging continues, since the negative electrode storage compartment has been filled with lithium atoms, subsequent lithium metal will accumulate on the surface of the negative electrode material.These Lithium atoms will grow dendrites from the surface of the negative electrode towards the lithium ions. These lithium metal crystals will pass through the separator paper and short circuit the positive and negative electrodes.
Sometimes the battery explodes before a short circuit occurs. This is because during the overcharging process, the electrolyte and other materials will crack and produce gas, causing the battery shell or pressure valve to swell and burst p>
Crack, allowing oxygen to enter and react with the lithium atoms accumulated on the surface of the negative electrode, then explode.
Therefore, when charging lithium batteries, the limIte upper voltage must be defined,
so that battery life, capacity and safety can be considered at the same time. . The optimal upper limit of charging voltage is 4.2 V.
Lithium batteries should also have a lower voltage limit when discharging.
When the cell voltage is lower than
2.4V
,
some materials will start to be destroyed.
And since the battery will discharge automatically,
the longer it sits, the lower the voltage will be. Therefore, it is better not to put it at 2.4V when discharging.
Stop. During the period when the lithium battery is discharged from
3.0 V
to
2.4 V
Energy is only about 3% of the battery capacity.
Therefore, 3.0V
is an ideal discharge cutoff voltage.
When charging anddischarge, in addition to voltage limitations, current limitations are also necessary. When the current is too high, the lithium ions do not have time to penetrate the storage location and will accumulate on the surface of the material.
Baidu Encyclopedia-Lithium Battery