How to disassemble Xiaomi Power Bank 20000 mAh: detailed instructions with photos and repair tips

Xiaomi Mi Power Bank 20000 mAh is one of the most popular portable chargers on the market, but even it is not immune to breakdowns. Over time, batteries lose capacity, connectors wear out, and the case can crack from a fall. If your device stopped holding a charge, does not turn on or requires cleaning contacts, self-disassembly often becomes the only economical solution.

In this article, we will discuss how to safely open the case of Xiaomi Power Bank 20000 (PLM05ZM, PLM06ZM, PLM07ZM and analogues) without damaging the internal components. You will learn what tools you need, how to avoid short circuits, and what to do if the device does not work after dismantling, and we will also reveal some hidden design nuances that are not written in the standard instructions.

Preparation for disassembly: tools and security measures

Before you start screwdrivers, make sure you have everything you need. Disassembling a power bank is about working with lithium-ion batteries that, if handled improperly, can overheat, ignite or explode, so the first step is to make sure that you're safe.

Here is the minimum set of tools and materials:

• 🔧 Plastic mediators (or guitar mediators) - for neat opening of the body without scratches.
• 🔨 Cross screwdriver (usually suitable PH00 or PH0).
• 🧲 Magnetic mat or tray - so as not to lose small screws.
• 🔋 Multimeter – to check the voltage on the contacts (optional, but recommended).
• 🧤 Rubber gloves – protection against static electricity and accidental circuits.
• 📸 Smartphone for photos – fix every step so as not to confuse the order of assembly.

⚠️ Warning: If the power bank is swelling, has visible damage to the case or produces an unpleasant odor, don't disassemble it yourself. Lithium-ion batteries in this condition are extremely dangerous. Take the device to a service center or dispose of it according to local regulations.

Also, prepare your workspace: the desk should be clean, without metal objects that can cause a circuit; it is better to work on a dielectric surface (wood, plastic); If you plan to replace batteries, purchase similar in capacity and size (for example, Samsung INR18650-20Q or LG MJ1).

Step 1: Removal of the upper body cover

The Xiaomi Power Bank 20000 mAh has two parts, clamped together by screws and latches, starting with the top cover (where the USB- ports and indicators are located).

Procedure:

1. Put the powerbank face down (so that the button and ports are at the bottom).
2. Carefully insert the plastic mediator into the gap between the top and bottom of the case. Start at the corner next to the USB-Type-C port - there the latches are less durable.
3. Smoothly drive the mediator along the seam, alternately snapping the locks. Apply a moderate force - if the body does not respond, do not press harder, but check if all latches are released.
4. When all the latches on one side open, lift the lid, but do not remove it completely - it can be connected by a plume to the board.

In some models (for example, PLM07ZM) there are 4 screws under the lid - they need to be twisted with a cross screwdriver. In newer versions, there may be no screws, and the lid is only held on the latches.

Step 2: Disconnect the plume and remove the control board

Once you remove the lid, you'll see a control board with chips, USB- ports and LED lights, and it's connected to the battery pack with a thin plume or wires.

How to properly disconnect the fee:

• 🔌 If the plume is attached to the connector, gently slap it with a plastic blade and unplug it. Don't pull the wires!
• 🔧 If the wires are soldered, take a picture of their location, then solder off with a soldering iron (power not more than 30 watts).
• ⚡ Before disconnecting, check the voltage on the battery contacts with a multimeter. The normal value is 3.7-4.2 V on each cell. If the voltage is below 2.5 V, the battery is deeply discharged and may be defective.

On the management board, pay attention to:

• 🔍 Charge/discharge controller (usually marked BQ, TI or IP53xx).
• 🔋 MOS transistors are responsible for protection against KZ and overheating.
• 💡 LED lights – they can be replaced if they don’t burn.

⚠️ Warning: If you see contact oxidation (green or white) when you disconnect the board, clean them with alcohol and cotton swab, which is a common cause of unstable powerbanks.

Step 3: Removing the battery pack

The battery pack in Xiaomi Power Bank 20000 mAh consists of two lithium-ion elements of 18650 format, connected in parallel.

• 🔋 Welded together with a nickel tape.
• 🔧 Fixed to a plastic holder.
• 📦 Wrapped in a thermal shrink film or insulation tape.

How to safely remove batteries:

1. If the elements are glued tape - carefully cut it with a knife, without touching the battery case.
2. If soldered with nickel tape, warm up the adhesive with a soldering iron and separate the cells from each other. Don't overheat the batteries!
3. Check each element with a multimeter. If the voltage on one of them is 0 V or well below the second, it needs to be replaced.

The table below shows the characteristics of the original Xiaomi batteries and their analogues:

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If you're replacing batteries, you're going to use cells with the same capacity and internal resistance, and that's more than 10 percent of the difference, and that's going to reduce the life of the entire unit.

Step 4: Diagnostics of malfunctions

Now that the power bank is dismantled, you can identify the cause of the failure, and here are the most common malfunctions and their signs:

• 🔌 Not charging from the network — a problem in the USB-Type-C port, charge controller or fuse.
• 🔋 Fails to charge—the MOS transistors, the discharge controller, or the batteries themselves are faulty.
• 💡 Do not light the indicators - check the LED chain and their soldering to the board.
• 🔥 Overheats when operating - short circuit in batteries or damage to the protection circuit.

How to check the management fee:

1. Turn the multimeter into vertebrae mode and check the integrity of the tracks on the board.
2. Make sure there is a 5V voltage at the USB-Type-C input when charging.
3. Check the resistance between the + and - terminals of the battery - it should be at least 10 kOhm (otherwise there is a KZ).

If you find burnt-out components (blackened chips, bloated capacitors), they need to be replaced. This will require a soldering station and experience with SMD- components. Otherwise, it is easier to buy a new fee (they are sold on AliExpress on request Xiaomi Power Bank 20000 PCB).

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In 80% of cases, the power bank does not work due to the imbalance of the batteries (one element is discharged more than another), just replace the faulty element and the device will work.

Step 5: Replace batteries and build

If the diagnostics show that the battery is a problem, we will start replacing it. It is important to use the same type and capacity as the original ones. For example, for the Xiaomi PLM05ZM, the Samsung INR18650-20Q or LG MJ1 will suit.

Replacement procedure:

1. Salt new batteries with nickel tape, observing the polarity (+ to +, - k).
2. Insulate the soldering places with a shrink tube or tape.
3. Install the block back into the case, securing it with double-sided tape or the original holder.
4. Connect the control board, making sure that the plume or wires are not twisted.

When assembling the body, make sure that:

• 🔌 All the latches are in place, or the lid will hang.
• 🔧 The screws were twisted with moderate force (do not tug!).
• 📶 There were no short circuits between the batteries and the board.

⚠️ Warning: After the battery is replaced, be sure to complete 2-3 full charge/discharge cycles to balance the cells.

Step 6: Checking performance and calibration

After assembly, connect the power bank to the charging and check:

• 🔋 Whether the charge indicators are on.
• 📱 Does it give current to the connected device?
• 🌡️ Does the housing overheat (norm to 40–45 °C)?

If the indicators are not working correctly (for example, they show 100% charge when connecting to a phone), you need to calibrate the controller.

1. Completely discharge the power bank before automatic shutdown.
2. Charge it to 100% and hold on charging for another 2-3 hours.
3. Repeat the cycle 2-3 times.

If after replacing the batteries, the capacity seems less than the declared one, check:

• 🔌 soldering quality – poor contact reduces the current output.
• 📊 Controller settings – some boards limit current to 1–1.5 A at the output.

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To increase the life of a new battery, store the power bank at 40-60% charge and avoid full discharges below 20%.

Frequent Mistakes and How to Avoid Them

Even experienced masters sometimes make mistakes when disassembling Xiaomi Power Bank 20000 mAh.

• 🔨 Too much opening force, causing cracks in the body or damage to the latches, so you can use plastic mediators and heat the body with a hair dryer (up to 50 °C) to soften the adhesive.
• ⚡ Short circuit soldering -- occurs when you touch both + and - contacts at the same time. Solution: work with rubber gloves and use a battery holder.
• 🔋 Using batteries of different capacity leads to a rapid imbalance. Solution: buy cells from the same batch.
• 📉 Improper calibration after replacement -- the indicators are lying, the capacity seems smaller. Solution: run 3 full charge/discharge cycles.

If after assembly the power bank does not include:

1. Check the polarity of the battery connection.
2. Make sure the control board gets power (call the multimeter).
3. If the controller is burned, replace it or contact the service.

FAQ: Answers to Frequent Questions