The most polluting element in lithium batteries is Co. The positive electrode is lithium. Cobalt oxide is ranked 27th in the periodic table of elements, behind iron and ahead of nickel. As a transition metal, it is ranked 27th in the periodic table of elements. an impact on the environment, but not great.
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 materials form tiny nanoscale storage networks, which can be used to store lithium atoms. In this way, even if the hull of the batterie breaks and oxygen enters, the oxygen molecules will be too large to enter these small storage compartments, so the lithium atoms will not come into contact with the 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 lithium battery cell voltage is higher than 4.2V, the number of lithium atoms remaining in the positive electrode material is less than half.
At this time, the memory cell often collapses, causing permanent shrinkage. in battery capacity.
If charging continues, since the storage compartment of the negative electrode has been filled with lithium atoms, subsequent lithium metal will accumulate at thesurface 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 upper voltage limit must be set
In order to take into account both lifespan, capacity and battery safety. The ideal upper limit of the tCharging voltage is 4.2 V.
Lithium batteries must 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 voltage will decrease as it is discharged. Therefore, it is better not to stop discharging at 2.4 V. During the period when a lithium battery is discharged from 3.0 V to 2.4 V
, the energy released only accounts for about 3% of the battery's capacity.
Therefore, 3.0V is an ideal discharge cutoff voltage.
When charging and discharging, 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