11.1v 5000mAh Falw Detector Li ion Battery Pack
Introduction: The flaw detector is a portable industrial non-destructive testing instrument. It can detect, locate, evaluate and diagnose many kinds of defects (weld, crack, inclusion, folding, pore, sand hole, etc.) inside the workpiece quickly, conveniently, nondestructively and accurately. It can be used not only in the laboratory but also in the engineering field. The instrument can be widely used in manufacturing, iron and steel metallurgy, metal processing, chemical industry and other areas requiring defect detection and quality control. It is also widely used in aerospace, railway transportation, boiler, pressure vessel and other areas of in-service safety inspection and life assessment. It is necessary for non-destructive testing industry. Portable flaw detector has become an important tool for on-site testing in modern society. Providing efficient, portable, portable and sufficient backup power solutions for portable flaw detector is an important guarantee for testers to carry out long-term on-site work. 18650 lithium battery pack has become the preferred solution for backup power supply of such high-tech test instruments because of its unique advantages.
1. Design requirements of spare lithium batteries for flaw detector:
Because of the high voltage and long working time of the flaw detector, the quality of the equipment itself and the sustained stability of the power supply are particularly critical, which requires that the power supply of the flaw detector must be realized through the multi-series and parallel combination of large-capacity single lithium batteries. In the working process of the flaw detector, a large number of valuable data need to be kept continuously, so accurate battery power display and alarm system must be provided. To prompt users to save data in time to improve the effectiveness of the work. Intelligent chip is used in the spare lithium battery scheme of the flaw detector. The host computer continuously reads the power and related important data in the smart chip through I2C communication mode, and monitors the battery from time to time in order to prompt users to carry out relevant operations in a reasonable and timely manner. The integrated Sanyo cores in our scheme have the advantages of high energy ratio, light weight, small volume, high cycle life, high safety, high voltage and good consistency. The lithium battery pack is designed to output over-current protection value 12A, continuous working current 7A and charge capacity 5000mAh, which fully meet the power demand of the instrument. Specific design parameters are as follows:
1) Design requirements of lithium battery pack model: 18650-3S2P/5000mAh/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 section overdischarge protection voltage: 2.40+/-0.08V
4. Single section over-discharge recovery voltage: 3.00+/-0.10V
5. Overcurrent Protection Value of Combination Batteries (10ms): 30-35A
6. Overtemperature protection value (recoverable): 70-plusmn; 5 C
7. The finished batteries also have short circuit and backcharge protection.
3) Battery cycle life design requirements: 300-500 cycles (national standard charging and discharging standards)
4) Battery Outside Size Design Requirements: Reference Battery Shell
2. Design scheme of spare lithium battery for flaw detector:
1) Intelligent Calorimeter Protection Board (PCM): SBS intelligent battery management system is used to calculate accurately the battery's power by using advanced power calculation principle. The battery's power information is reported to the host computer through SMBUS, and the rechargeable smart battery pack is protected. Due to the chemical characteristics of lithium battery itself, it is necessary to provide overcharge, overdischarge, short circuit, overcurrent and overcurrent. Overtemperature and other protective functions to avoid the danger of combustion, explosion and so on.
2) 18650 lithium ion core/18650/2500mAh/3.7V Li-ion cell (SANYO).
3) Temperature switch: mainly for the design of temperature protection function. When the temperature of the battery itself reaches 70-plusmn due to other abnormal problems; when the temperature is in the range of 5 C, the temperature switch acts to protect the temperature.
4) Field effect transistor (MOSFET): MOSFET plays a switching role in the protection circuit, which will never increase or decrease the voltage at both ends of the load and ensure voltage stability.
5) Battery Package (Shell)