HOW DOES LITHIUM-ION BATTERY WORKS?

HOW DOES LITHIUM-ION BATTERY WORKS?

HOW DOES LITHIUM-ION BATTERY WORKS?


Imagine a world where all cars are driven by induction motors and not internal combustion engines. Another huge disadvantage of IC engines is that they only produce usable torque in a narrow band of engine RPM.

 Considering all of these factors, induction motors are definitely the perfect choice for an automobile. However, the power supply for an induction motor is the real bottleneck in achieving a major induction motor revolution in the automobile industry.

Who Discovered Batteries?

 Let's explore how Tesla, with the help of lithium-ion cells, solved this issue and why lithium-ion cells are going to become even better in the future. Let's take a Tesla cell out from the battery pack and break it down. 

HOW DOES LITHIUM-ION BATTERY WORKS?

You can see different layers of chemical compounds inside it.

Tesla's lithium-ion battery works

 Tesla's lithium-ion battery work is an interesting concept associated with metals called the electrochemical potential. Electrochemical potential is the tendency of a metal to lose electrons.
 In fact, the very first cell,developed by Alessandro Volta more than 200 years ago, was based on the concept of electrochemical potential. A general electrochemical series is shown here.

How Lithium Looses Electrons?

 According to these values,lithium has the highest tendency to lose electrons and fluorine has the least tendency to lose electrons. Volta took two metals with different electrochemical potentials, in this case, zinc and silver, and created an external flow of electricity.


Which Company made First Battery Using lithium-ion?

 Sony made the first commercial model of a lithium-ion battery in 1991. It was again based on the same concept of electrochemical potential.

 Lithium, which has the highest tendency to lose electrons, was used in lithium-ion cells. Lithium has only oneelectron in its outer shell and always wants to lose this electron. Due to this reason, pure lithiumis a highly reactive metal. It even reacts with water and air.

 The trick of a LITHIUM-ION battery operation is the fact that lithium, in its pureform, is a reactive metal. In any case, when lithium is essential for a metal oxide, it is very steady.

 Assume that somehow we haveseparated a lithium atom from this metal oxide. This lithium atom is highly unstable and will instantly form alithium-ion and an electron. However, lithium, asa part of metal oxide, is much more stable than this state. Start New Search 

A compact powersupply has become the life saver of the advanced mechanical world, particularly the lithium-particle battery. 

Envision an existence where all vehicles are driven by enlistment engines and notinternal burning motors. 

Enlistment engines are farsuperior to IC motors in practically all designing perspectives, just as being more hearty and less expensive. 

Another tremendous detriment of IC motors is that they just produce usable force in a tight band of motor RPM

Thinking about these variables, acceptance engines aredefinitely the ideal decision for a vehicle. 

Be that as it may, the force supplyfor an acceptance engine is the genuine bottleneck in accomplishing a significant enlistment engine upset in the vehicle business. 

We should investigate how Tesla, withthe help of lithium-particle cells, fathomed this issue and whylithium-particle cells will turn out to be stunningly better later on. 


How about we take a Tesla cell out from the battery pack and separate it?

You According to these values,lithium has the most noteworthy inclination to lose electrons and fluorine has minimal propensity to lose electrons. 

Volta took two metals with various electrochemical possibilities, for this situation, zinc and silver, and made an externalflow of power. 


Sony made the principal business model of a lithium-particle battery in 1991. 

It was again founded on a similar idea of electrochemical potential. 

Lithium, which has the highest tendency to lose electrons, was utilized in lithium-particle cells. 

Lithium has just one electron in its external shell and consistently needs to lose this electron. 

Because of this explanation, unadulterated lithiumis a profoundly receptive metal. 

The stunt of a lithium-ionbattery activity is the way that lithium, in its pureform, is a responsive metal. 

In any case, when lithium is essential for a metal oxide, it is very steady. 

Expect that some way or another we haveseparated a lithium iota from this metal oxide. 

LITHIUM-ION battery module

This lithium molecule is exceptionally temperamental and will in a flash structure alithium-particle and an electron. 

Be that as it may, lithium, asa some portion of metal oxide, is substantially more steady than this state. 

In the event that you can give two unique ways to the electron and lithium-particle stream between the lithium and the metal oxide, the lithium molecule will consequently arrive at the metal oxide part. 

During this cycle, wehave delivered power from the electron flowthrough the one way. 

lithium particles

From these conversations, obviously we can create power from this lithium metal oxide, on the off chance that we initially separate out lithium particles from the lithium metal oxide, and also, control the electrons lostfrom such lithium molecules through an outer circuit. 

We should perceive how lithium-particle cells accomplish these two targets. a commonsense lithium-particle cell likewise utilizes an electrolyte and graphite.Graphite has a layered structure.

 These layers are loosely bonded so that the separated lithium-ions can be stored very easily there. The electrolyte between thegraphite and the metal oxide acts as a guard which allowsonly lithium-ions through.

What happens when you connect charger to phone?

 Now let's see what happens when you connect a power source across this arrangement. The positive side of the powersupply will clearly pull in and eliminate electronic the lithium particles of the metal oxide.These electrons flowthrough the external circuit as they cannot flowthrough the electrolyte and reach the graphite layer.

 In the meantime, the positively charged lithium-ions will be attracted towards the negative terminal and will flow through the electrolyte.

 lithium-ions also reachthe graphite layer space and get trapped there. Once all the lithium atomsreach the graphite sheet, the cell is fully charged. Thus we have achieved the first objective which is the lithium-ionsand electrons detached from the metal oxide. As we discussed, thisis an unstable state, as if being perched on top of a hill.

 As soon as the power source is removed, and a load is connected, thelithium-ions want to go back to their stable state asa part of the metal oxide. Due to this tendency,the lithium-ions move through the electrolyte and electrons via the load, just like sliding down a hill.

 Thus we get an electricalcurrent through the load. Please note that that graphite does not have a role in the chemical reactionof the lithium-ion cells. Graphite is just a storage medium for lithium-ions.

 If the internal temperature of the cell rises due to some abnormal condition, the liquid electrolyte will dry up and there will be a shortcircuit between the anode and cathode and this can leadto a fire or an explosion. 

To avoid such a situation,an insulating layer, called the separator, isplaced between the electrodes. The separator is permeablefor the lithium-ions because of its micro porosity.

 In a practical cell, the graphite and metal oxide are coated onto copper and aluminum foils. The foils act as current collectors here and the positive and negative tabs can be easy taken out from the current collectors.

 An organic salt of lithiumacts as the electrolyte and it is coated on tothe separator sheet. All these three sheets arewound onto the cylinder around a central steel core, thus making the cell more compact.

 A standard Tesla cell has a voltage of between three and 4.2 volts. Many such Tesla cellsare connected in series and in a parallelfashion to form a module.

 16 such modules are connected in series to form a battery pack in the Tesla car. Lithium-ion cells produce a lotof heat during the operation and the high temperature willdecay the cells' performance.

Battery management system

 A battery management system is used to manage the temperature,state of charge, voltage protection and cell health monitoring of such a huge number of cells. Glycol-based cooling technology is used in the Tesla battery pack.

 The BMS adjusts to the glycol flow rate to maintain the optimum battery temperature. Voltage protection is another crucial job of the BMS. For example, in these three cells, during charging a higher capacity cell willbe charged more than the rest.

Balancing of Cell

 To solve this problem, the BMS uses something called cell balancing. In cell balancing, all the bells are allowed to charge and discharge equally,thus protecting them from over and under voltage.

 This is where Tesla scores over Nissan battery technology. The Nissan Leaf has a huge battery cooling issue due to the big size of itscells and the absence of an active cooling method.

 The small multiple cell design has one more advantage. During high power demand situations, the discharge strainwill be divided equally among each of the cells. Instead of many small cells if we had used a single giant cell, it would have been putunder a lot of strain, and eventually it wouldsuffer premature death.

 By using many small cylindrical cells, the manufacturing technology of which is already well established, Tesla clearly made a winning decision. There is a magical phenomenon which happens within lithium-ion cellsduring their very first charge that saves the LITHIUM-ION ells from sudden death. Let's see what it is.

 The electrons in the graphite layer are a major problem. The electrolyte will be degraded if the electrons comeinto contact with it. However, the electronsnever come into contact with the electrolyte dueto an accidental discovery, the solid electrolyte interface.

 When you charge thecell for the first time, as explained above, the lithium-ions move through the electrolyte. Here, in this journey, solvent molecules in the electrolyte cover the lithium-ions.

 When they reach the graphite, the lithium-ions, along with the solvent molecules, react with the graphiteand form a layer there called the SEI layer.

 The formation of this SEI layeris a blessing in disguise. It prevents any direct contact between the electrons and the electrolyte, thus saving the electrolytefrom degradation.

 In this overall process of theformation of the SEI layer, it will consume 5% of the lithium. The remaining 95% ofthe lithium contributes to the main working of the battery.

 Even though the SEI layer was an accidental discovery, with over two decades of research and development, scientists have optimized the thickness and chemistry of the SEI layer formalin cell performance. 


It's amazing to find outthat those electronic gadgets we used around two decades back did not use lithium-ion batteries. With its amazing speed of growth, the lithium-ion battery market is expected to become a $90 billion annual industry within a few years. 

The currently achieved numberof charge discharge cycles of a lithium-ion battery is around 3,000. Great minds across the globeare putting their best efforts into increasing this to 10,000 cycles.

 That means you would not have to worry about replacing the batteryin your car for 25 years. Millions of dollars have alreadybeen invested in research into replacing the storagemedium graphite with silicon.

 If this is successful, the energy density of the lithium-ion cell will then increase by more than five times. We hope this video provided you with a clear conceptual understanding about lithium-ion cells and their future.

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