Lithium Batteries

So, let’s talk about the batteries first , as we all know that overcharging of batteries can reduce and partial charging and discharging can extend the lifetime of batteries. The battery should never be discharged too low . Humans have became familier to batteries from 80’s and 90’s era. Some recent researches showed that batteries can be recharged within few seconds to 100% . Of course the experiment were done in lab with strictly experimental conditions and will be seen commercially in market after few decades.

A battery converts chemical energy into electrical energy by a chemical reaction. Basically the chemicals are kept inside of the battery. The battery produces direct current(DC) electricity (electricity that flows in one direction and not switch back and forth.) batteries exist in our cars , laptops and other electric appliances.A battery is essentialy a can full of chemicals that produce electrons.

Now let’s come to lithium batteries , it is widely used all over the world from electric vehicles to NASA’s spacesuit. These batteries are light weight and commercially available online easily at decent price.

As working of Lithium batteries is quite simple.

The lithium ion cell consists of 4 main parts i.e, cathode(+ve terminal) , Anode(-ve terminal) , electrolyte and porous separator. The anode is of graphite and cathode is always a lithium compund mixed with other materials. The electrolyte is an organic compound which contains lithium salts to transfer lithium ions. The porous separator allows the lithium ions to pass through itself while still separates the anode and cathode within the cell. After when the cell is discharged , the ions just moves from the anode to the cathode by passing through the electrolyte , this discharges electrons on the anode side, powering the circuit after that ultimately any device connected to the circuit. After when the cell is recharged, this process is reversed and the lithium ions pass back from the cathode to the anode.

Now let’s come on the quality of lithium batteries. If you’re buying batteries of brand like companies like Panasonic and Samsung which is available all over the world, you’ll not get a bad review but if you’re buying cheaper batteries your appliance could be damaged. Other small companies have a lower standards , and if you’re making a large battery then a single weak quality cell can end up to show negative impact to other cells. Some companies like trustfire and surefire buys the used batteries from big companies and repacked the same thing and sell it to a cheaper rate.

As we all know that large amount of energy contained in a small volume so it could be dangerous to use a lithium batteries. So we should use them properly and efficient way to power the appliance, never leave lithium batteries charging unattended.

Nowadays when the electric cars are in high demand , the lithium batteries are gone cheaper because it is manufacturing at a large scale. But ihe more challenging thing is that we can’t get batteries of our own shape because the batteries are made on large scale and if we want to make battery of our own then we should learn how it works and how the batteries are made in industries.

Lithium batteries are made in different form fsctor ways but the manufacturing construction is always the same.

Let’s start from the pouch cells. Pouch cells are the simplest form of lithium battery cells. It has two terminal at the edge of the pouch. Inside the cell there are anode and cathode on the opposite sides separated by the porous separator and an electrolyte on the either side. It looks like a sandwish is folded back and forth many times within the pouch so the capacithy of battery will increase. There are no standard size of pouch cells, manyn companies make it designed to exact sizes for different products like in cell phone , so that perfect space should be there in cell phone the design of the battery shape should be like that to increase the productivity of that cell phone company. One advantage of puch cells is that it is cheapand lightweight to produce. Some disadvantage of puch cells is that there is no protective case is given to the cell to safe it from being damaged. Like if you have heard about the news that Xiaomi RealMi 6 phone have blasted due to excessive internal heat and there was no protective case over it also to safe the phone , obviously some external pressure is also had applied to phone that could be reason for that blast.

After that xiaomi released Redmi Note 5 pro which I have till now in which a small graphite layer had been placed so that phone won’t be heated.

When a pouch cells ages it expands , this is done due to small interior shorts that occur due to time as the battery ages, creating gas that might expand the cell size because the cell is tightly sealed and they have no place to escape. The expansion of pouch cells makes the reduction in performance, but when the expansion is more it could rupture explosively.

In case of prismatic cells they can quite similar to pouch cells ,difference is that they have rigid rectangular case outside of the cell , this gives the cell the rectangular shape, they are less space efficient cells the pouch cells. They have thin tab terminals , it allows a nut or bolt to be used for connections. This makes it easier to join prismatic cells to large battery modules. .

Now in the case of cylindrical cells they are AA style batteries which we use in our remote controls , torch and other electrical appliances. They are made by rolling up the same amount to same content of a pouch cell. Unlike prismatic cells and pouch cells cylindrical cells are made in standard sizes.

There are many cylindrical cells like 18650 , 21700 , 14500 etc. where in 18650 , 18mm is the diameter and 65 is the length of cell. While 18650 cell is used in laptops , flashlights etc. But I like the most the 21700 cell not only because it is widely used in Tesla but also because it is slightly larger cell than 18500 and comes in greater capacity than 18500. Actually these cells was designed specifically for Tesla. There are more other cells but they are made by welding two cells to connect them together .

General lithium battery cell summary

Lithium ions are most common and easiest to work with li-ion 18650 cylindrical cells. There are dozens of great quality top branded cells are available in market plus hundreds of off brand and generic 18650 li-ion cells. We can finf cheap , low power Li-ion cells like Samsung ICR18650–26F cells are perfect and low power projects. Sony US18650VTC5, which have the same approximate capacity, size and weight but can provide over 600% more power!

We can now find Li-ion cells that contain a massive amount power in the size of your thumb.

Now shall we come on the battery management services(BMSs), most BMSs for lithium ion batteries have cut of discharge at around 2.7V — 2.9V per cell. Discharging below 2.5 V will cause irreparable damage to the cell.

Lithium Manganese Oxide LiMn2O4 can handle relatively

high power in very short bursts and offers high thermal stability.

Lithium Cobalt Oxide LiCoO2 uses a layered cobalt structure in its cathode. It is relatively low cost and high capacity, but generally has a lower current rating and only moderate cycle life.

Lithium Ion Polymer Battery

Lets know something of Lithium polymers(li-poly or lipo or RC lipo). There are most amount of confusion regarding lithium polymers because the term cells , lithium polymer cells and the lithium polymer are not the same thing.

This new technology promishes to be incredibly safe batteries .

The problem was that dry electrolyte didn’t conduct electricity very fast at surrounding temperature. This means that the batteries had to constantly heated to work properly. The confusion starts when what the people call lithium polymer but this is not true it should be lithium ion polymer batteries.

The main difference is that lithium-ion polymer batteries use a micro-porous electrolyte instead of the normal porous separator layer placed in the electrolyte of lithium ion cells. At last the use of li-ion cells in Radio Controlled(RC) toys and vehicle that are generally called as lipo batteries. These are high power cells which are specifically used in the RCindustry for their ability to provide the highest possible current.

This means that all “lithium ion polymer ” and “lithium ion” are available today are technically lithium ion batteries. I will not use the term lithium polymer as any cell in market being called “lithium polymer ” today is really just lithium ion and the real “lithium polymer ” cells never really made it out of the lab. Another thing is that RC lipo batteries are the dangerous ones.

RC Lipo Cells

RC lipo cells are a specialty chemistry based on lithium cobalt that is suited for high power applications. They can provide super high discharge rates for long periods of time, and insanely high discharge rates for short periods (before they overheat and we will back to that unfortunate fire scenario I told above about it).RC lipo battery is exclusively using in remote controlled vehicle industries for applications like RC drones , helicopter , planes , cars etc.

RC lipo batteries are the cheapest lithium cells available , they cost muchless than li-ion and LiFePO4 cells.

Discharging a RC lipo cell below 2.5 volts and then charging the cell can result in combustion of the cell, especially at higher charging currents. For this reason, RC lipo cells must be monitored carefully during discharge as well to ensure that they are never drained too far.

In few years manufacturing and production of batteries will change and improved as we enter the era of lithium batteries.