Smartphones have been among the major beneficiaries of rechargeable battery technologies. Otherwise if batteries never existed, we would only be able to use our phones when they are directly plugged into power. Imagine how that would be! But thanks to rechargeable battery technology that has been improving over the years. The improvements made are mainly to make the batteries safer, more durable, store more energy per unit volume also to become cheaper.
For instance, the cots per KWH of Li-ion batteries were $1200 in 2010. This cost is now under $200 in 2020. This is about 80% reduction in the price within 10 years. This reduction has made it cheaper for smartphone companies to add bigger batteries in their smartphones without any significant increase in price. At the moment we have smartphones that have batteries with over 4000mah but costing less than $300. This wasn't possible 10 years back when the cost per KWH of these batteries was still above $1000
What phones have lithium batteries
Cell phones all the way from the late1990s till today mainly use Lithium-ion batteries as their source of power. However, there are some earlier phones that used Nickel-Cadmium batteries instead of Lithium. In recent years Nickel-cadmium battery technology has been phased out by Li-ion batteries thanks to the many benefits that Li-ion has over other battery technologies.
Li-ion batteries are preferred because of their high energy density, durability and lightness that is very important in the designing of phones. The earlier challenge of Li-ion batteries was mainly their price but this problem is slowly being solved as the prices of Li-ion batteries are going down every year that passes.
As of 2020, almost all smartphones and other cells phones mainly use Li-ion batteries. There are other battery technology alternatives that are being researched like the Fluoride-ion batteries that are meant to address some of the challenges that Li-ion batteries face. However, all these alternatives still have a couple of years to be validated to get into the general market. So, Li-ion batteries are still expected to dominate the next 10 years as the most used battery technology in cell phones.
Which type of battery is used in mobile phones?
There are two main Lithium battery technologies used in phones today. These are Lithium polymer batteries and lithium ion batteries. The main difference between the two is that Lithium polymer batteries use a polymer electrolyte instead of a liquid electrolyte that is used in lithium-ion batteries.
Lithium polymer batteries are a newer technology to Lithium-ion batteries and are also more expensive due to the many benefits they give over Li-ion batteries. Let us look at some of these benefits;
"They have a higher energy density than Li-in batteries. This means you can pack more energy per unit volume in Li-Poly batteries than Li-ion batteries. This makes it possible to have smaller batteries with more capacity which is a huge factor in smartphones manufacturing.
"Li-Poly batteries are also more moldable than li-ion batteries. This makes it possible to make batteries of any shape without compromising the performance of the battery in the device
"Lithium polymer batteries also have less internal resistance. This makes it possible to fast charge these batteries without any significant increase in internal temperature of the batteries. The battery can also be used for lots of tasks without overheating since it has a higher maximum discharge current.
"Less self-aging rate than Li-ion batteries. If you left a Li-ion and Li-poly batteries stored without use, the Li-poly battery will have a higher battery capacity than the Li-ion when you check on them after a couple of years. This aspect is important for people who do not use their devices heavily. So, they can use their batteries for a couple of years before the need for replacement.
"They are also less vulnerable to high temperatures. Li-ion batteries tend to lose a lot of their capacity when exposed to high temperatures than Li-poly batteries. This makes the Li-poly batteries much safer to use even when in places that have high temperatures without worrying of the battery life and possible explosion of the battery itself.
The only challenge with Li-poly batteries is their price. Since the technology of Li-poly batteries is still new, it is still more costly to design and manufacture these batteries than Li-ion batteries. That is why most of the smartphones are still using Li-ion batteries. Li-Po batteries are more popular in electric cars and plane industries thanks to the many advantages they have over other alternatives like Ni-Cad.
Can cell phone catch fire?
The answer to this question is YES. We can look at a case study of the Samsun galaxy Note 7 that made lots of news in 2016 after a couple of them caught fire. The main reason behind this was related to the battery, cooling systems and circuits that distribute power to the different motherboard components. This phone was finally discontinued and those who returned their galaxy note 7 phones were given the galaxy s7 edge in return.
The main cause of fire is normally a short circuit within the battery system. When Samsung carried out an investigation as to why the batteries were catching fire, they found out that it all started when the anode and cathode of the batteries started crimping. This caused the separator between the two electrodes to weaken hence causing a short circuit. The heat that damaged the two electrodes was as a result of limited space between the heat-sealed protective pouch around the battery and its internals. This meant there was limited space to emit heat from the battery onto the casing and then outside the phone.
In that case the problem was with the design battery systems. But in some situations, a phone may catch fire due an old battery whose separator has been weakened over time. Hence lead to a short circuit that causes the fire. Another issue could be a result of physical damage on the battery that may lead to damaging the electrodes or the separator which may also lead to a short circuit and catching fire.
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