Lithium ion batteries (LIB), also written as Li-ion battery, is a type of secondary cell, i.e. it is a rechargeable battery type that can be charged, discharged and recharged severally. These batteries consist of one or more electrochemical cells connected together; a lithium based derived compound (e.g. lithium oxide) is used as the positive electrode, carbon (graphite) is used as the negative electrode, and the solution of lithium salt in an organic solvent serves as the electrolyte.
The performance of lithium-ion batteries improves the performance of most electric devices, however special care must be taken in handling these batteries during the end of its life cycle, else the risk of an accident (fire, pollution or explosion) occurring.
Lithium ion batteries must not be disposed with regular waste because they contain various chemicals and lithium is very reactive and difficult to control; these batteries must not be crushed, punctured or mishandled, to prevent short circuiting. Damaged lithium batteries should not also be packed with good ones or stored up in a place not specifically designed to accommodate them. Basically, lithium batteries if not properly discarded can lead to a strain which in turn causes a release of heat (an exothermic reaction) to the environment.
There are basic necessities to be given attention to when handling lithium ion batteries, they are:
- A specialist should be met to remove batteries from electronic devices, if they cannot be removed easily; avoid using force.
- Insulate the terminals of the batteries or wires to prevent current from travelling along unwanted areas with low impedance (short circuit)
- Package damaged batteries in approved barrels or boxes, isolating layers with dry sand, and use an extra package for swollen batteries
- Avoid placing large numbers of batteries together without accurate separation, as this could lead to fire hazard
- Avoid storing discarded lithium ion batteries as this leads to extra risk.
Recycling process aims at reducing the number of batteries being disposed, as they contain chemicals and metals that pollute the environment.
ARE LITHIUM BATTERIES RECYCLABLE?
Yes, Lithium batteries are recyclable, that is they can be broken down and their components used to make other high end valuable products. Components like graphite, aluminum, and plastic, contained in lithium ion batteries can be recycled. These contents are less toxic than those in other battery types, hence making the recycling process a little less difficult.
ARE LITHIUM BATTERIES HAZARDOUS WASTE?
Though the lithium ion batteries promote electronic devices, they are however not environmentally friendly. Damaged Lithium batteries are hazardous waste products because it contains lots of chemicals that are very reactive, and once tempered with becomes difficult to control. Factors such as strain (such as puncture or crush), high temperature, high voltage and short circuit, can lead to a thermal reaction and escalate to explosion.
Lithium-ion batteries contain a sheet of polypropylene which isolates electrodes and prevents short-circuiting; a crush or puncture however could destroy this protective sheet, and lead to ignition of any flammable material around. All of these concerns show the hazard involved in handling lithium batteries, hence proper measures must be taken.
Lithium batteries are classified as miscellaneous hazardous materials and extra care and several restrictions must be met during the transportation, an example is ensuring the devices containing these batteries are properly sealed and are contained in a strong outer coverage to prevent damage or exposure of contents during handling.
HOW ARE LITHIUM BATTERIES DISPOSED OF PROPERLY?
Damaged lithium batteries are recycled in permitted treatment facilities. They are discarded as e-waste (electronic waste) and kept in the appropriate collection point and moved to the specified facilities. When handling these damaged batteries, it is important to keep them away from direct prolonged sunlight or high temperature, water or humidity. The batteries are packaged carefully in safety casings, and cores are prevented from coming in contact with each other; the batteries are discharged first before any form of processing is carried out. The lithium batteries contain recyclable constituents such as: metal compounds, ferric metal, Aluminum, Copper, graphite and plastic. Proper packaging of the damaged lithium batteries keeping at designated centers for collection ends the discarding process for a novice in battery recycling.
The following steps are taken in an authorized recycling plant to properly discard lithium batteries via recycling, mechanical, pyrometallurgical and hydrometallurgical treatments are applied:
THE RECYCLING PROCESS:
1.First step is deactivation; this involves full discharge of stored energy to prevent any thermal occurrence. The electrolyte can also be frozen using liquid nitrogen, to prevent any electrochemical reactions during crushing
2.Organic solvents of the electrolyte are recovered in a vacuum via condensation, and nontoxic gases are produced
3.Mechanical process of crushing the batteries is employed to separate cooper, aluminum, separator, lithium and coating materials
4.Pyrometallurgical process is used to extract the metals via thermal treatment (melting of the battery) to produce cast (nickel, cobalt and copper) and slag (lithium and aluminum)
5.Hydrometallurgical process which involves leaching, extraction, crystallization and precipitation is carried out to recover pure metals like lithium.
Note that this process regains graphite, lithium carbonate, nickel sulphate and manganese sulphate, reduces CO2 footprint, saves energy and produces less hazardous gases. During recycling safety measures against possible electrical, chemical and thermal reactions should be put in place.
Recycling is the best way to discard lithium batteries; the recycling process begins with sorting the batteries into the constituent elements, removing combustible materials, such as plastics and insulators using a thermal oxidizer. Scrubbing removes pollutants created by burning, leaving clean cells with metal content; the cells are chopped and heated to liquid metal, burning off nonmetals, and allowing the alloy to settle. Cadmium which is very light evaporates first and the vapour is cooled and condensed to produce a pure cadmium of 99.95%. The pigs or hogs, which represent the liquid metals are sent to metal recovery plants and separate to pure nickel, chromium and iron; these metals are used to produce other high end products such as stainless steel.
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