Compared with other high-energy secondary batteries (such as Ni Cd battery, Ni MH battery, etc.), lithium ion battery has significant advantages in performance, mainly in the following aspects.
(1) High operating voltage
Using carbon lithium intercalation compounds such as graphite or petroleum coke instead of metal lithium as negative electrode will reduce the battery voltage. However, due to their low lithium intercalation potential, the voltage loss can be minimized. At the same time, selecting the appropriate lithium intercalation compound as the positive electrode of the battery and the appropriate electrolyte system (which determines the electrochemical window of the lithium battery) can make the lithium battery have a higher working voltage (- 4V), which is much higher than that of the aqueous solution battery.
(2) Large specific capacity
Although replacing metal lithium with carbonaceous materials will reduce the material mass specific capacity, in fact, in order to ensure that the battery has a certain cycle life, the negative metal lithium is usually more than three times excessive. Therefore, the actual reduction of mass specific capacity in lithium battery is not large, and the volume specific capacity is almost not reduced.
(3) High energy density
The higher working voltage and volume specific capacity determine the higher energy density of secondary lithium battery. Compared with the widely used Ni Cd battery and Ni MH battery, the secondary lithium battery has the highest energy density and still has great development potential.
(4) Good safety performance and long cycle life
The reason why the battery with metal lithium as anode is unsafe is that multiple charges and discharges change the cathode structure of lithium-ion battery and form porous dendrites. When the temperature increases, it has a violent exothermic reaction with the electrolyte, and the dendrites can pierce the diaphragm and cause internal short circuit. However, the lithium battery does not have this problem, so it is very safe. In order to avoid the presence of metal lithium in the battery, the voltage shall be controlled during charging. For safety, the lithium battery is equipped with multiple safety devices. In the process of charging and discharging, there is no structural change in the insertion and de insertion of lithium ions on the cathode and anode (there will be some expansion and contraction of the lattice in the insertion and de insertion process), and because the lithium intercalation compound is more stable than metal lithium, lithium dendrites will not be formed in the process of charging and discharging, which significantly improves the safety performance of the battery and greatly improves the cycle life. Lithium batteries were excluded from dangerous goods by the dangerous goods transportation division of the U.S. Department of transportation and iait (International Aviation and Transportation Association) in 1989 and 1990, respectively.
(5) Low self discharge rate
Lithium battery adopts non-aqueous electrolyte system, and lithium embedded carbon material is thermodynamically unstable in non-aqueous electrolyte system. In the first charge and discharge process, due to the reduction of electrolyte, a layer of solid electrolyte mesophase (SEI) film will be formed on the surface of carbon negative electrode, which allows lithium ions to pass but does not allow electrons to pass, and makes the electrode active substances with different charged states in a relatively stable state, so it has a low self discharge rate.
(6) Clean and pollution-free
Lithium battery does not contain toxic substances such as lead, mercury, etc. at the same time, because the battery must be well sealed, there is little gas emission during use, which does not pollute the environment. The solvent used to dissolve the binder in the manufacturing process can also be completely recovered. Sony and other large lithium battery manufacturers have started the recycling of lithium batteries and the recycling of materials (such as metal drills) since 1997. In addition, in 1996, Sony's lithium battery was identified to comply with IS014001 international environmental standard [71o]
(7) High current efficiency
Unlike any previous secondary battery in aqueous solution system, lithium battery will not produce gas during normal charge and discharge, and the current efficiency is close to 100%. This property is especially suitable for battery pack for power storage and conversion.
The above is the analysis and introduction of the advantages and characteristics of aluminum battery by the Xiaobian of Guangdong lithium battery manufacturer. Do you understand it? If you want to know more, please contact us Yidian new energy!
