Features and Advantages of Lithium Battery

Lithium batteries have attracted great interest and attention due to their high specific energy, long cycle life, and wide operating temperature range. In particular, the average price of each cycle battery is not high, and it is also declining. trend. The advantages and characteristics of lithium batteries are described in more detail below.

Compared with other high-energy secondary batteries(such as Ni-Cd batteries, Ni-MH batteries, etc.), lithium-ion batteries have significant performance advantages, mainly in the following aspects.

(1) High operating voltage

The use of carbon lithium compounds such as graphite or petroleum Coke instead of metallic lithium as a negative electrode will reduce the battery voltage. However, due to the low potential of lithium embedded in them, voltage loss can be reduced to a minimum. At the same time, choosing a suitable lithium-embedded compound as the positive electrode of the battery and selecting an appropriate electrolyte system(which determines the electrochemical window of the lithium battery) can make the lithium battery have a higher operating voltage(-4V), which is much higher than the aqueous solution system battery.

(2) Higher than capacity

Although replacing metal lithium with carbon material will reduce the material quality over capacity, in fact, in order to ensure that the battery has a certain cycle life, negative metal lithium is usually more than three times excessive. Therefore, the actual reduction of mass to capacity in lithium batteries is not significant, and the volume to capacity is almost not reduced.

(3) High energy density

The higher working voltage and volume ratio determine the higher energy density of secondary lithium batteries. Compared with the currently widely used Ni-Cd batteries and Ni-MH batteries, the second lithium battery has the highest energy density and still has great development potential.

(4) Good safety performance and long cycle life

The reason why batteries with lithium metal anodes are unsafe is that multiple charge and discharge of electricity causes the positive structure of lithium ion batteries to change, forming porous dendrites. When the temperature is raised, it undergoes a violent exothermic reaction with the electrolyte, and dendrites can pierce the diaphragm., causing internal short circuit, The lithium battery does not have this problem and is very safe. In order to avoid the presence of metallic lithium in the battery, the voltage must be controlled when charging. For safety, the lithium battery is equipped with multiple safety devices. Lithium-ion batteries are inserted and de-embedded on the cathode and anode during charging and discharge without any structural changes(the lattice will expand and contract somewhat during insertion and de-embedding), and because lithium compounds are more stable than metallic lithium, Lithium dendrites will not be formed in the process of charging and discharging, thus obviously improving the safety performance of the battery, and the cycle life is also greatly improved. Lithium batteries were excluded from dangerous goods in 1989 and 1990 by the Dangerous Goods Transport Department of the United States and IAIT(International Air Transport Association), respectively.

(5) Low self-discharge rate

Lithium battery adopts non-aqueous electrolytic fluid system, and the thermodynamic instability of lithium-embedded carbon material in non-aqueous electrolytic liquid system. During the first charge and discharge process, a layer of solid electrolyte intermediate phase(SEI) membrane will be formed on the surface of the carbon negative electrode due to the reduction of the electrolyte, allowing lithium ions to pass through but not allowing electrons to pass through, and making electrode active substances in different charged States. In a relatively stable state, Therefore, it has a low self-discharge rate.

(6) Clean and non-polluting

Lithium batteries do not contain toxic substances such as lead, Fu, and Mercury. At the same time, because the battery must be well sealed, very few gases are released during use and there is no pollution to the environment. Solvents used to dissolve binders during manufacturing can also be fully recycled. Major manufacturers of lithium batteries such as Sony have started the recovery of lithium batteries and the recycling of materials(such as metal drills, etc.) since 1997. In addition, Sony's lithium battery was identified in 1996 as meeting the IS014001 international environmental standards[ 71O

(7) High current efficiency

Unlike any previous secondary cell in an aqueous solution system, lithium cells do not produce gas during normal charging and discharging processes, and the current efficiency is close to 100 %. This property is particularly suitable for batteries for power storage and conversion.

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