Converting a mouse dry cell battery into a lithium battery_V1.0

This mouse battery can be converted from a dry cell battery to a lithium battery, integrating charging and battery protection.
It features an ultra-compact size of only 11*31mm
, supports charging and over-discharge protection, and uses a diode-based step-down output to minimize standby current.
 
Wiring method:
 
 
Actual effect:
A red light illuminates during charging, and a green light illuminates
when fully charged. The lithium battery operates at 4.2V, with a fully charged output voltage of approximately 2.5V. It works perfectly with my Logitech mouse .
Due to the complex internal space of the mouse, it is recommended to disconnect the Type-C port and insert it into the mouse using a jumper wire
. When not used for mouse modification, it can also be used as a lithium battery charging module. To use this, remove the output diode and short-circuit the diode pads with a wire.
Note:
The project involved two boards, one single-sided and one three-panel. Since free prototyping did not allow for panelization, a panelization without V-cutting was used. It is recommended to choose a board thickness of 0.8mm for prototyping to facilitate cutting and insertion into the mouse.
Defect: This battery protection chip does not automatically activate after installing the battery. It needs to be activated by plugging in the charger after replacing the mouse battery. This is not a problem if the battery is soldered securely.