Optical fiber welding machine is mainly applied to the operators, engineering companies, enterprises and institutions of the optical fiber cable line construction, line maintenance, emergency repair and production testing of optical fiber devices in a research of teaching and scientific research institutes, the equipment is mainly released by arc two optical fiber fusion, at the same time by using the principle of the collimating gently forward, so as to realize the coupling of optical fiber mode field. For the convenience of construction, the market has developed hand-held fiber fusing machines, ribbon fiber fusing machines specially for Fusing ribbon fiber, and leather fiber fusing machines for fusing leather fiber cables and jumpers, etc. Because the invention of portable optical fiber welding machine has become an important tool for the staff to carry out field testing, and providing efficient, portable, light and sufficient backup power supply solutions for the optical fiber welding machine is an important guarantee for the staff to carry out long-term field work. Because of its unique advantages, 18650 lithium battery pack has become the first choice of backup power supply solutions for such high-tech test instruments.

1. Design requirements for spare battery of optical fiber welding machine:

    The backup battery of the fiber splicer needs automatic protection function of 70 degrees temperature. Equipment start the instantaneous current demand is bigger, peak current can be up to 15 to 20 a, normal working current 2-3 a, the continuous operation demand is higher, the battery for our company in optical fiber welding machine backup battery USES the import sanyo batteries, sanyo batteries with high energy ratio, light quality, small volume, high cycle life, high safety, high voltage, as well as good consistency, The designed output overcurrent protection value of lithium battery pack is 25A, the continuous working current is 7A, and the charged capacity is 7800mAh, which can fully meet the electricity demand of the instrument. Specific design requirements are as follows:

1) Lithium battery pack model design requirements: 18650-3S3P/7.8Ah/11.1V.

2) Circuit design requirements:

1, single overcharge protection voltage: 4.35±0.25V

2, single overcharge recovery voltage: 4.15±0.50V

3, single overdischarge protection voltage: 2.40±0.08V

4, single overdischarge recovery voltage: 3.00±0.10V

5, the combination battery overcurrent protection value (10ms) : 20~30A

6, the combination battery overtemperature protection value (recoverable) : 70±5℃

7, the finished battery also has short circuit, reverse charge protection.

3) Battery cycle life design requirements: 300~500 times (GB charge and discharge standard)

4) Design requirements for battery appearance and size: refer to the battery shell

Second, the spare battery design of optical fiber welding machine

1) Protection board (PCM) : it is mainly a protection line designed for rechargeable lithium battery pack. Due to the chemical characteristics of lithium battery itself, it is necessary to provide intelligent power calculation, overcharge, overdischarge, short circuit, overcurrent and other protection functions to avoid combustion, explosion and other dangers.

2) Protection IC (Protection IC) : the design of the main protection function chip, the cell overcharge, overrelease, overcurrent, short circuit and other functions of online monitoring, so that the cell in a safe, stable and efficient range of work.

3) Temperature switch: mainly designed for temperature protection function. When the battery temperature reaches the range of 70±5 ° C due to other abnormal problems, the temperature switch is turned on for temperature protection

4) 18650 lithium ion cell: 18650 2600mAh 3.7V

5) field effect tube (MOSFET) : MOSFET tube plays a switching role in the protection circuit, always make the voltage at both ends of the load will not increase nor decrease, to ensure voltage stability.

6) Battery package (housing)