Is a Power Bank a Lithium ion Battery?
May. 20, 2022
Imagine you are stranded in the woods and your cell phone battery is about to run out of juice at 1%.
Your chances of getting help are very limited.
A power bank bank will be able to solve your problem.
It is a portable battery charger that can charge many devices such as cell phones, digital cameras, portable speakers, Bluetooth headsets and more.
The power bank contains a rechargeable battery that can store an electrical charge that can then be used to charge the above mentioned electronic devices.
But is a power bank supply a lithium-ion battery? Lithium-ion batteries are the most commonly used rechargeable batteries in power bank because of their high energy density and low discharge rate, as well as their cost effectiveness.
There are other types of rechargeable batteries available, including lithium polymer (Li-Po) and nickel cadmium (Ni-Cad) for power bank.
Wireless Power Bank MW-2101
Power bank
power bank helps solve many problems, mainly that you can charge your devices when you are not at home or at the office where the power outlet is located.
It gives you peace of mind when traveling to places where these power outlets are difficult to find over long distances.
Let's take a closer look at power bank.
The heart of a power bank source is the rechargeable battery.
Without this major component, power bank would be useless.
A rechargeable battery has the ability to be charged, discharged to a load and then recharged many times.
Regular batteries (disposable batteries) can only be used once and then must be disposed of, which does not make them a viable option for power bank.
Other parts of a power bank supply include: the charging circuit, the battery protection circuit, and the boost converter.
Charging Circuit
The main purpose of the charging circuit is to provide constant DC (direct current) or pulsed DC power to the power bank's rechargeable battery.
Battery Protection Circuit
Sometimes you will charge your power bank and forget to remove the charger, leaving it plugged in for longer than necessary.
Fortunately for us, the battery protection works to protect the power bank's battery from overcharging.
It also protects the battery from high temperatures.
Boost Converter
The boost converter circuit in a power bank supply steps a low voltage between 3.7 and 3.85 volts to a standard operating voltage of 5 volts (which is used by most electronic devices).
10,000mah Wireless Power Bank MW-WL1802
Why do power bank supplies use lithium-ion batteries?
Lithium-ion rechargeable batteries are not the only batteries available when designing power bank supplies, but they are the most common.
In the early days, NiCd batteries were the rechargeable batteries for portable devices and wireless communications.
Lithium-ion is now the battery of choice and is used in almost all portable electronics and can even be found in electric vehicles.
Lithium-ion batteries contain an electrolyte through which lithium ions are transported from the negative terminal to the positive terminal.
Compared to NiCd batteries, Li-ion batteries have a higher energy density (typically twice as high), but there is still room to further increase the energy density.
In addition, lithium-ion batteries are less expensive to maintain than other rechargeable batteries. There is no memory and no need for periodic cycling to extend the life of the battery.
The following are additional characteristics of lithium-ion batteries.
| Specific energy | 100 – 265 W.h/kg |
| Energy density | 250 – 693 W.h/L |
| Specific power | ~250 – ~ 340 W/kg |
| Charge/Discharge efficiency | 80 – 90% |
| Self – discharge rate | 0.35% – 2.5% per month |
| Nominal voltage | 3.6 / 3.7 / 3.8 / 3.85 Volts |
| Cycle life | 400 – 1200 cycles |
Li-Ion vs. Li-Polymer power bank. Which is better for power bank?
As we have seen, NiCd batteries were used back in the infancy of portable technology, and now Li-Ion batteries are the popular choice.
However, there is another very popular rechargeable battery, and that is the lithium polymer rechargeable battery.
Which battery is better for power bank?
Let's take a look at the advantages and disadvantages of these two batteries, which will give us a better idea of which is the better choice for power bank.
Lithium-ion Advantages
● High energy density
● Low self-discharge
● Low maintenance
● Specialty batteries for high current applications
Disadvantages of lithium-ion
● Needs protection circuitry to prevent overvoltage and current
● Will age relatively quickly if not stored in a cool environment
● High manufacturing cost
● Still in evolutionary stage (numerous improvements underway)
Advantages of Lithium Polymer
● Stylish, compact design
● Flexible
● Lightweight
● Improved safety
Disadvantages of lithium polymer
● Lower energy density and reduced cycle times
● No standard size
● Higher cost-to-energy ratio
So, both types of batteries have their advantages and disadvantages.
But how do we know which is better to use in a power bank supply?
There are several requirements to consider for what constitutes an effective power bank source, which ultimately depends on the battery.
● Cost
● Life cycle
● Capacity
Cost
First and foremost is cost.
For anything you buy, you don't want it to cost you an arm or a leg.
The same can be said for purchasing a power bank supply.
While both types of batteries are relatively expensive to manufacture, lithium polymer batteries have a higher cost to energy ratio.
Therefore, it is more cost effective to use Li-ion batteries for power bank because it costs less to get the same amount of energy as a Li-polymer battery.
Life Cycle
It doesn't make sense to have a power bank supply that only lasts 10 uses and then has to be discarded.
The goal is to have a power bank that lasts a long time.
The life cycle of a power bank is the number of times you can charge and discharge it before the battery runs out.
There are many factors that determine the life cycle of a battery, such as capacity, storage, etc.
However, in general, lithium-ion batteries are known to have a higher number of cycles compared to lithium polymer batteries.
Capacity
The final requirement for an effective power bank is its capacity
The capacity of a power bank is the amount of power it can store and thus charge other portable electronic devices.
If the power bank has less power than your phone, it will be meaningless.
This means you will have to charge the power bank several times to fully charge your phone, thus rendering it useless.
The capacity of a power bank is directly related to the energy density of the battery it uses.
The higher the energy density of the battery, the more power it can store, so you can charge your portable electronic device multiple times.
Lithium-ion batteries have a higher energy density than lithium polymer batteries.
Therefore, you can see that lithium ion meets all three requirements that determine the effectiveness of power bank, making it a better choice.
Health and safety issues with Li-Ion battery power bank?
While they have many advantages and reasons for use in power bank, lithium-ion batteries are known for exploding and catching fire.
As a result, they have many restrictions when traveling by air, especially as carry-on luggage.
Therefore, check with the airline you may be flying with to find out what restrictions they have on power bank using lithium-ion batteries.
Always store power bank in a cool place out of direct sunlight.
