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PCB/PCBA knowledge
Power bank circuit board - the ultimate guide for beginners

Power banks are a great power source when out of your house. This convenient and portable power source can charge your phones several times. While this magical device has so many usages, if you are a manufacturer of a power bank circuit board or want to build your own power bank, this article is meant for you.

This article deals with an insight into power bank circuit board or power bank PCB, that act as one of the core parts of a power bank.

Table of Contents

What is power bank circuit board?

A power bank printed circuit board is a piece of silicon chip, that acts as a mainboard of the power bank. When assembled, a power bank PCBA has power input and output points, capacitors, diodes, etc., that make it possible to hold the charge in the batteries and discharge them when needed.

A power bank circuit board is responsible for making a power bank work. It acts as a central mediator between the batteries and your mobile phone. Therefore, power bank circuit board is the most crucial part of the power bank.

What’s inside a power bank?

What is inside a power bank
What is inside a power bank

Below is the list of what you’ll find in a power bank.

1.Printed circuit board assembly
The most important thing is the circuit board, that has several outputs and one input. Nowadays, the input point (to charge your power bank) either comes in Micro USB or Type-C format. Then there are several output points (strictly in USB), that help you charge your mobile phone. Several output points (preferably 3) are embedded on the circuit board to facilitate charging several devices.

Moreover, a good quality power bank circuit board allows simultaneous charge and discharge, which means that you can charge your power bank while also connecting your mobile phones to charge them, all at once.

Since a power bank circuit board has the primary function of charging and discharging the power bank, it’s also called “charge/discharge module”.

Batteries are where your power bank stores all the charge. These batteries are mostly lithium-ion or lithium polymer batteries. The lithium-ion batteries don’t have the capacity to withstand overcharge, which is why, the circuit board has to be designed in such a way, that it can cut off charging when the batteries of a power bank are fully charged.

The batteries usually have a nominal voltage of 1.2 volts with a current ranging from 2000 mAh or more. These batteries are connected in a combination of series and parallel connection, so as to achieve a voltage of 4.8v.

The current of a power bank can differ from one model to another. For instance, a power bank might have a current capacity of 11,000 mAh, while some might have 6,000 mAh. Modern power banks now have a capacity of 20,000 mAh or even more, which is possible because of high capacity batteries.

3.Metal plates
When the batteries are placed in the power bank’s body, they need to be connected with some good conductors of electricity. To do that, two thin aluminum or copper plates are used (one for negative and one for positive connectors) to connect all the batteries with the power bank circuit boards. Most power bank manufacturers avoid using wires and prefer these metal plates, which are a crucial part of a power bank.

What are the different types of power bank circuit boards?

Types of power bank circuit board
Types of power bank circuit board

A brief list of types of power bank circuit boards are listed below:

1.Single-layer PCB
This is the most common type of PCB and perhaps the most sensible option to use in a power bank. A power bank just has a micro-USB connector female, 3 USB connectors female, a couple of LEDs (to indicate the remaining battery and charging status), a few resistors, capacitors, and diodes. These components can be easily assembled on a single-sided PCB to shrink the costs.

2.Rigid PCB
A rigid PCB usage in power banks makes a perfect sense, since they’re capable of withstanding heavy loads. Power banks go through rigorous charge and discharge, which is why making a charge/discharge module using a rigid PCB would be a great idea.

What role of PCB plays in power bank?

The role of PCB in power banks is very interesting. Below is what a PCB does in a power bank.

1.Charge/discharge: The primary purpose is to charge the batteries in the power bank and discharge them when required.

2.Protect the batteries from overcharging: This role is very important in power banks. A power bank circuit board will automatically cut off the charge when the batteries are fully charged. This allows elimination of severe overcharging, that would cause blasting of batteries in the worst case scenario.

3.Act as a flashlight: In most power bank circuit boards, you’ll find a flashlight LED, that has high lumens, so you can use your power bank as a spare emergency flashlight.

4.Bridge the gap between various units: Various units here means input socket, output sockets, and batteries. These components are always connected through power bank circuit board, which is why the circuit board also acts as a mainboard.

How is power bank circuit board made?

Making a power bank is a complex process, which is why there are limited manufacturers in the world. Below are quick steps to making a power bank:

1.PCB preparation
First, you’ll have to get a design prepared, which will contain all the essential information about what components need to be on your PCBA. Get the PCB designed, so that the components can be assembled on it.

2.Get the PCBA assembled
A PCBA will have all the components as identified in the first step.

3.Battery connection
The PCBA will have two points (Battery +ve and –ve). Create a battery pack by connecting batteries in parallel. These batteries need to be connected to the PCB’s battery terminals.

Connect the power bank to a power source and charge the batteries for a few hours. Then connect your smartphone to the USB output, and check if the phone starts charging.

5.Getting the body ready
After the tests and trials succeed, you’ll have to get in touch with a plastic molding company, who can create bodies for your power bank circuit board and battery. The body may also be referred to as “PCB housing” or “power bank PCBA housing”.

What factors should be considered when designing a power bank circuit board?

Factors should consider for designing power bank circuit board
Factors should consider for designing power bank circuit board

When you get in touch with a PCB maker for your power bank project, you should take these things into consideration.

1.Make sure that the PCB has one charging point in USB Type-C mode. Micro USB is getting depreciated and several governments have started to switch to Type-C for all electronic devices for consistency. This means that your power bank should get charged via USB Type-C input.

2.Always ensure that the PCB has several charging points to facilitate multiple device charging. Ideally, go with a PCB with at least 3 fast charging points for output.

3.Ask the PCB manufacturer if they’ll make the PCB in such a way that it can charge and discharge the power bank simultaneously. This means that the PCB should be responsible for supporting charge and discharge at the same time.

4.Ensure that the PCB has an automatic charge cut-off to prevent batteries from getting overcharged.

How does the power bank circuit board module work?

The working structure of power bank circuit board is very complex, but interesting.
1.The PCB charges the battery when connected to a power input source such as a wall socket adapter.

2.The battery starts charging and the PCB shows the status of charge through a set of LEDs.

3.The PCB stops charging the battery when fully charged. This is achieved with the built-in function in the PCB.

4.When the smartphone or any other device is connected to the power bank, the PCB starts charging the connected device and discharges the battery.

What faulty can be inspected in a power bank circuit board?

Ways to inspect a defective USB power bank module
Ways to inspect a defective USB power bank module

Many people get confused between a faulty power bank ciuciut board and battery pack. Below are some points that tell that your power bank PCB is faulty.

1.Try to sniff the power out port. If it smells like burnt, your PCB has been short circuited. It’s damaged.

2.The battery status LEDs might function unusually, indicating a faulty power bank circuit board.

3.If the flashlight isn’t working, it could be a sign of faulty PCB.

4.If the power bank is charging the devices perfectly but the power bank itself isn’t getting charged, perhaps the PCB is faulty. In that case, the power bank will keep functioning until the battery gets fully discharged.

Selecting the right power bank PCB maker- How?

Now, if you’re wondering how to land the best power bank PCB maker, here’s a list of selection criteria:

1.Always go with a maker, who promises to deliver the products as per your requirement.

2.It’s not true that only the experienced ones give quality products. Feel free to deal with a new maker in the market. Just ask for samples and test their quality before moving to bulk orders.

3.You should go with a maker, who can also give you quality batteries. While not all the power bank circuit board makers sell batteries, you can ask your supplier if they can offer you the batteries too.

4.Go with a supplier who can consider your less quantity orders too.

5.A good supplier is one, who is honest, and deals with you in an honest manner. The supplier shouldn’t lie about anything.


One of the leading power bank PCB makers is IBE Electronics. If you’re having trouble finding a good supplier, you can skip testing other suppliers and go with IBE Electronics. You’ll get the best assistance with quality PCBs on time. If you’re a new brand, you can contact IBE Electronics for less quantity orders initially.


mAh (or milliamp-hours) capacity measures how much charge the battery can hold. It represents how long it can power another appliance before you need to recharge it.

1. PCB preparation

First, you’ll have to get a design prepared, which will contain all the essential information about what components need to be on your PCBA.

2. Get the PCBA assembled

A PCBA will have all the components as identified in the first step.

3. Battery connection

The PCBA will have two points (Battery +ve and –ve). Create a battery pack by connecting batteries in parallel. 

4. Testing

Connect the power bank to a power source and charge the batteries for a few hours. 

1. Always go with a maker, who has passed the cerfitication or standard on power bank manufacturing.

2. Cooperated with manufacturer who has experienced on power bank cirucuit boards.

3. Do more survey or research on the reputation, and product quality of power bank circuit board manufacturer before you make the final decision.

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