1. Design requirements
Electric scissors are hand-held electric tools that use a motor as a power source to drive the working head through a transmission mechanism to perform cutting operations. The electric scissors are composed of a motor, a gearbox, an eccentric shaft-link mechanism, a switch, a non-reconnectable plug and a cutter. The electric scissors developed and produced by Dongguan KAYO is a lithium battery scissors with strong power. It is necessary to satisfy the pruning of large-caliber branches, and to ensure that when the load of the scissors reaches the limit, the lithium battery can quickly make a protective action to avoid damage caused by the current. The lithium battery is required to be very accurate when supplying power, and after overcurrent protection , the battery can quickly restore the power supply.
2. Design plan
1) Protection board (PCM): This is a compact lithium battery with high power and accuracy. It has high power, high current, and strong intelligence. It has very high requirements for the control board, so we need to protect The circuit is subjected to multiple comparison tests, and the hardware and software system of the protection board is independently developed to ensure that the battery can work normally and stably in extreme environments. Due to the chemical characteristics of the lithium battery itself, it is necessary to provide intelligent power calculation, overcharge, overdischarge, Protection functions such as short circuit, over current and over temperature. In order to avoid dangers such as burning and explosion.
2) IC: The main protection function chip of the design scheme, which performs online monitoring of overcharge, overdischarge, overcurrent, short circuit and other functions of the battery cell. Make the batteries work in a safe, stable and efficient range.
3) Agreement: no need to have
4) Overcurrent fuse/1 level 2 protection circuit: In addition to active protection, passive trigger protection is also indispensable.
5) 18650 lithium battery cell: The combination of the international first-line brand of 18650 lithium battery cell, the consistency and stability of the battery cell, ensure the service life of the entire battery pack, but also stable current output.
6) Battery pack packaging: shock-proof and explosion-proof structure, fire-proof and anti-fall shell.