r03 battery.Working principle and purchase method of BMS lithium battery protection board

　　The working principle and purchase method of BMS lithium battery protection board. The BMS lithium battery protection board is very important. In the battery protection system, the lithium battery protection board or the corresponding BMS must be used in the lithium battery PACK design process to better design the lithium battery pack, and can even assist the quality department to analyze abnormal batteries or circuit. In this article, the editor will introduce the principles and purchasing tips of lithium battery protection board BMS.

　　The main components of lithium batteries:

　　Lithium batteries are mainly composed of two large parts, the battery core and the protective plate PCM (power batteries are generally called battery management systems BMS). The battery core is equivalent to the heart of the lithium battery, and the management system is equivalent to the brain of the lithium battery. The battery core is mainly composed of positive electrode material, negative electrode material, electrolyte, diaphragm and casing, while the protective board is mainly composed of protection chip (or management chip), MOS tube, resistor, capacitor and PCB board.

　　What is BMS?

　　BMS is actually a lithium battery management system. As the name suggests, it is a module specially used to manage the operation and management of lithium batteries. The object is lithium batteries. The main target is secondary batteries, mainly to improve battery utilization and prevent overcharging and over-discharging of batteries. It can be used in electric vehicles, battery cars, robots, drones, etc. In addition, BMS is also a common storage format for computer music and game files and the name of a new generation of telecommunications business management systems.

　　Working principle of BMS lithium battery protection board:

　　The reason why lithium batteries need protection is determined by its own characteristics. Since the material of the lithium battery itself determines that it cannot be overcharged, overdischarged, overcurrent, short-circuited, or charged and discharged at ultra-high temperatures, lithium battery components always appear with a delicate protective board and a current fuse.

　　The BMS protection function of lithium batteries is usually completed by a protection circuit board and current devices such as PTC. The protection board is composed of electronic circuits and can accurately monitor the voltage and charge and return circuit of the battery core at all times in an environment of -40°C to +85°C. current, and timely control the on-off of the current loop; PTC prevents severe damage to the battery in high-temperature environments.

　　Ordinary lithium battery BMS protection boards usually include control IC, MOS switches, resistors, capacitors and auxiliary devices FUSE, PTC, NTC, ID, memory, etc. Among them, the control IC controls the MOS switch to turn on when everything is normal, so that the battery core is connected to the external circuit. When the battery core voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off to protect the battery core. Safety.

　　Introduction to BMS lithium battery protection functions:

　　1. Battery protection is similar to PCM, including overcharge, over-discharge, over-temperature, over-current, and short-circuit protection.

　　2. Energy balance. Since many batteries are connected in series, the entire lithium battery pack will eventually show great differences after working for a certain period of time due to the inconsistency of the cells themselves and the inconsistency of the operating temperature. The life of the battery and the use of the system have a huge impact. Energy balancing is to make up for the differences between individual cells and perform some active or passive charge or discharge management to ensure the consistency of the battery and extend the life of the battery.

　　3. SOC calculation. Due to the development of technology, many methods have been accumulated for SOC calculation. If the accuracy is not high, the remaining power can be judged based on the battery voltage. The most accurate method is the current integration method (also called Ah method), Q= ∫idt, as well as internal resistance method, neural network method, Kalman filter method, etc.

　　4. Communication. Different systems have different requirements for communication interfaces. The mainstream communication interfaces include SPI, I2C, CAN, RS485, etc. Among them, automotive and energy storage systems are mainly CAN and RS485.

　　⒌Balance between batteries: It is to charge the single lithium battery equally so that each battery in the battery pack reaches a balanced and consistent state. Balance technology is a key technology of battery energy management system that the world is currently researching and developing.

　　How to purchase BMS lithium battery protection board:

　　Nowadays, the market is flooded with various types of protective plate lithium batteries. Some of the better ones include Sanyo ones, while the worse ones include UF ones. The lithium battery protection plates themselves are also very different. It is very important to choose a protective plate battery that is suitable for your flashlight. Flashlights without protective circuits are usually used with protected batteries, such as incandescent bulb flashlights. As far as the battery cells themselves are concerned, the good quality and common ones include Sanyo, Panasonic, Sony, Samsung, and AW.

　　Sanyo: Suitable for high discharge platforms, usually for circuits larger than 1A it is recommended to use Sanyo. Sanyo's high-discharge platform lasts longer and has more power than Panasonic.

　　Panasonic: Suitable for low-discharge platforms. Panasonic is recommended for circuits usually less than 1A. Panasonic's low-platform discharge lasts longer than Sanyo's and has more power.

　　Sony: The performance is similar to Sanyo, but slightly lower than Sanyo. I haven’t used Sony since it was recalled because metal powder was mixed into the battery cell materials due to process reasons, which may cause fire and explosion. But it is said that it has been improved now, but it is used by Sanyo, so it is generally not considered unless the price is very suitable.

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