Xiaomi Redmi Note 7 has proven to be a reliable device with excellent value for money, but over time, even the best quality lithium-polymer battery loses its capacity. If your phone starts to quickly discharge, suddenly turn off at 20-30% charge or swelled up, lifting the rear panel, then replacing the battery becomes an inevitable procedure. Self-repair saves a significant amount, but requires accuracy and understanding of modern electronics.
The process of dismantling the battery in this model is complicated by the fact that it is attached to double-sided tape throughout the area, and the case itself has no screws on the outside. To successfully complete the task, you will need not only a new power source, but also a specific set of tools, as well as patience. It is important to understand that opening the case automatically voids the official manufacturer's warranty if it has not expired.
In this article, we will discuss all the steps of preparation and conduct of the procedure, paying special attention to safety when working with lithium cells. Wrong actions can lead to damage to plumes, battery rupture or even fire, so follow the instructions strictly. We will consider how to safely unplug the glass, disconnect the plumes and properly prepare the landing place for the new component.
⚠️ Warning: Before starting any work, make sure the phone is turned off. If the battery is too swollen and adjacent to the screen, any manipulation of the back cover carries the risk of damage to the display matrix due to pressure.
Tools and workplace preparation required
Quality repairs start with the right organization of space. You will need a clean, well-lit desk, preferably with antistatic coating or simply free of unnecessary items. To work with the Redmi Note 7 you will need a specialized tool that can be purchased in electronics repair kits. Using inappropriate items such as kitchen knives or thick needles can cause serious damage to the body.
The main list of tools includes a dryer (construction or household at maximum power), a sucker, a thin mediator or plastic card, a set of screwdrivers (including a cross and possibly a star), tweezers and isopropyl alcohol. Also, it will not be superfluous to have thermal glue or a special glue B-7000 to fix the new battery and the back cover.
☑️ Preparation for repairs
Special attention should be paid to safety. Lithium polymer batteries are sensitive to puncture and overheating. If you accidentally damage the battery shell with a metal tool, you can short circuit with heat and smoke, so metal blades are better replaced with plastic ones, and all movements should be smooth and controlled.
Dismantling of the rear glass panel
The most difficult step for many users is to remove the back cover, as Xiaomi uses an aggressive adhesive to seal the case. Heating should be done evenly throughout the perimeter of the device, avoiding prolonged exposure to the center where the camera and battery are located. The optimal heating temperature is about 80-90 degrees Celsius, which allows you to soften the adhesive, but not damage the internal components.
After the body has warmed up for 2-3 minutes, carefully install the suction cup at the bottom of the back panel. Pull the suction cup up, creating a small gap, and insert a plastic mediator or blade into it. Driving the tool along the faces, gradually cutting through the glue layer. Movements should be sliding, parallel to the plane of the smartphone, so as not to damage the glass.
What to do if the lid is not removed?
When the perimeter is passed, take your time to remove the panel completely. Inside it may be glued to the fingerprint scanner plume (although in the Note 7 it is more often on the plume coming from the board, but in some revisions there may be nuances with glue). Carefully examine the insides. If the lid is removed, put it in a safe place, putting a soft cloth under it so as not to scratch the glass.
Disabling the plumes and removing the protective plate
When you remove the back cover, you'll see the inside of the smartphone, and most of the space is occupied by the battery, and at the top is a motherboard that's covered with a black plastic or metal safety plate. To access the connectors, you need to unscrew all the visible screws that hold this plate. The screws may vary in length, so you should use a magnetic mat or layout.
Take the safety plate off carefully, and underneath it you'll see the main connectors: the display plume, the main camera plume, the front camera plume, and most importantly, the battery connector. The first thing you need to do is turn off the battery to shut down the device and eliminate the risk of short circuits in further manipulations, and use a plastic blade or nail to do that by lifting the connector up.
Then disconnect the other plumes that prevent full access to the bottom of the board or the charging module. Often you need to remove the board completely or lift it to get to the bottom screws of the case or the charging plume. Be careful with the fingerprint scanner plume if it comes in a separate wire, it is very easy to break when you move sloppy.
⚠️ Attention: Never pull the plume wires themselves. All connectors have locks or tight fits, they need to be snapped with a light swaying motion strictly vertically upwards.
Removal of the old battery
Now that the battery is open, you can start removing it. As mentioned earlier, the Xiaomi Redmi Note 7 uses double-sided tape all over the area. Trying to just pull the battery out with your fingers over the top edge will cause it to deform or rupture. There are several proven methods of safe extraction.
The first is to use floss or floss, thread under the top edge of the battery (on the board side), and, as you move left-right (sawing movements), gradually descend downwards, cutting through the adhesive layer, which is the safest method for battery integrity, but takes time and care.
The second method involves using plastic cards. After a little heating of the bottom of the case (where the battery is) with a hairdryer, try gently tweaking the edge of the battery with a plastic card. Move the card along the layer of glue, adding drops of isopropyl alcohol to facilitate the process. Alcohol penetrates the glue and significantly reduces its adhesion.
If the battery is too swelled, it can only be glued to the edges or pressed on the display, and you have to be careful, so don't try to bend the battery or put your effort into the center of it. Once you're successfully removed, immediately dispose of the old battery in a special battery container.
Installation of a new battery and assembly
Before installing a new battery, you need to thoroughly clean the seat of the residue of old glue and tape. Use a plastic blade and rag moistened with alcohol. The surface should be smooth and clean so that the new adhesive layer provides a reliable fixation. If you use a new two-way tape, stick it in strips around the perimeter and in the center, removing the protective film on only one side.
Put the battery in the case, making sure it's flat and doesn't protrude beyond the edges. Connect the battery connector to the motherboard before the characteristic click. Don't turn the phone on right away -- first check if the battery is properly in the niche and it's not interfering with the lid closing. Then reverse assemble: install the protective plate, twist the screws, connect the display and cameras.
| Parameter | Old battery | New battery | Norma. |
|---|---|---|---|
| Capacity | Less than 3,000 mAh | 4,000 mAh | 4,000 mAh |
| Tension. | 3.85 V (nominal) | 3.85 In | 3.85 In |
| Thickness | Bloated (>5 mm) | Flat (~4 mm) | Strictly on specification. |
| Status of contacts | Oxidized | Clean. | No pollution. |
The final step is to glue the back cover. Apply a thin layer of B-7000 glue or use a new complete adhesive layer around the perimeter of the case. Press the lid and lock the smartphone with rubber bands for 15-20 minutes before the initial grip. Full polymerization of the adhesive takes about 2-4 hours, so it's best not to put the phone under stress during this time.
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After the battery is replaced, perform a calibration cycle: discharge the phone to 0% (off), then charge to 100% when off, which will help the power controller correctly display the charge level.
Checking the performance and possible problems
After assembly, turn on the device. First, check if the screen is touch responsive, if the sound and vibration are working. Go to the settings and see the charge level. If the phone is on and shows charge, this is a good sign. However, it is worth doing a deeper diagnosis using the Xiaomi engineering menu.
To enter the engineering menu, dial the phone app code ##6484##. In the CIT menu that opens, select Battery or Charge. Here you can see the actual capacity, current voltage, temperature and connection status. If the system writes "Unknown" or shows incorrect data, it may not be the connector is fully connected.
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If the phone doesn't turn on after you've replaced it, don't panic. Check the density of the battery connector and make sure the protective plate doesn't crush the plumes.
Possible problems after replacement include no response to charging, quick discharge or heating in downtime. Often the cause lies in a poor battery or damage to the charging plume during disassembly. If heating is observed in the bottom of the housing where the charge controller is located, immediately turn off the device and check the connections.