How to replace battery cells inside laptop battery

To notebook the battery is very important as the mobile work. The notebook become to desktop without laptop battery. There are battery cells and protection board in laptop battery inside. The batteries cells supply the power and the protection panels protect the board safety when charging. Battery cells are consumable items, the capacity reduce in each using, which directly determine the quality of notebook batteries. Notebook battery life short suddenly , cant work, laptop battery down suddenly (such as: battery capacity suddenly reduce from 40% to 10% when working), laptop battery cant be fully charged, notebook battery cant be fully discharged (the notebook closed when the battery power state in 40% or more), the above cases may be caused by batteries capacity declining or batteries cells damage. Of course, there may be due to damage of the protection board, but this possibility is very small.


laptop battery cells

If you find that above failure happened to your notebook, it is necessary to check your laptop battery in laptop battery maintenance business. Now, let me introduce the whole process of laptop battery cells changing (for example Thinkpad T40 battery) . First, we use professional equipment to detect the cause of the malfunction. There are many types equipment of Battery Fault Detection, such as: Texas Instruments products, MAX products, Ateml products, and even some personal home-made products. Most we use the commonly Texas Instruments (Texas) EV2300


Use professional equipment and related software to detect the cause of the malfunction


Battery Fault Detection


Texas Instruments EV2300


Once detected 92P1101 battery cells faulty , we are prepare to change the batteries cells for notebook battery.

Before the battery cells changing, We would like to tell you about the structure of the notebook battery.


The 92P1102 laptop battery are made up of three parts: battery shell, battery cells and protection board.

In general, notebook battery can be divided into three parts: the shell, batteries and protection board‚


Battery shell

Battery shell. That is notebook battery casing. There are different three types: type, ultrasonic bonding and adhesive bonding type.


08K8193 Batteries cell

Batteries cells group, that is, combination the batteries cells together in parallel and series connection. In accordance with the parallel, in series of different combinations can be divided into: 2 parallel and 3 serial connection (the most common), 2 parallel and 4 serial, 2 parallel and 2 serial, 3 serial and 3 parallel and 3 parallel and 4 serial (relatively rare).


Protection panel

Protection board, which is based on an agreement SMB1.1 circuit board, with power management functions and charge-discharge management. Protection board, which is based on an agreement SMB1.1 circuit board. There are three chips on it : battery Measurement management chip, charge and discharge management chip and serial EEPROM memory chips


08K8192 Protection board


On positive plate : measuring management chip and charge-discharge management chip


The plate back has a serial EEPROM memory chips

Decrypt and unlock the protection board are two different works. Before you go into the battery management system you must decrypt the protection board, unlock the battery management system in order to change the parameters of the battery and use of information. If you only change batteries cells without unlock, you can not achieve satisfactory results (for example: the battery can only charge to the state “the last full charge capacity”, the battery maintenance management information will be displayed the charged number) We use professional equipment and related software to unlock and decrypt the protection board. Of course, you must choose the appropriate equipment by 92P1087 battery management chip design.


use professional equipment and related software to unlock and decrypt the protection board




choose the appropriate equipment by battery management chip design


related software for unlock and decrypt the protection board



If the protection board hardware damaged , we would also use oscilloscope, multimeter and logic analyzer


oscilloscope, multimeter


logic analyzer

After the deal with the batteries protection board , let me introduce the method to choose the right cells. We must use sub-meter cabinet and the internal resistance to check batteries capacity resistance, separation voltage, select out all specs of parameters for comparison with similar groups. Also the thinkpad R50 battery thinkpad T41 battery thinkpad T42 battery thinkpad T43 battery is the same battery cells.


Sub-capacity cabinet


Sub-capacity cabinet manage software




Select the similar cells to make a battery group

Then we will use the spot-welding and Nickel sheet to joint the batteries cells together.




use the spot-welding and nickel films to joint the 92P1011 batteries cells together


The Nickel sheet we use are designed in round corner round corner and straight angle Nickel sheet After unlock and decrypt the protection board, connect the battery cells group. We can assemble the shell protection board and cells together.



assemble the shell protection board and cells together

During the assemble, you must take high attention. The steps is also suitable for IBM 40Y679540Y6797 40Y6799. After doing the above steps, the battery cells changing is completed. The repaired battery quality is the new battery in most function, so you must calibrate it first. Generally, you should fully charged in 10 hours then full discharge it 2-3 times.


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