The difference between passive balancing and active balancing of iron lithium battery protection board. The lithium battery protection board, which plays an important role in the battery system, has gradually attracted everyone's attention as an effective means to extend battery life. Among them, the lithium battery protection board balancing system, which plays a key role, has also attracted widespread attention. Currently, there are two methods of balancing multi-series battery systems on the market: traditional passive balancing and active balancing.

　　Active equilibrium and passive equilibrium are one of the hot debates in the electric vehicle industry. It's very similar to the Qi Sect and Sword Sect of the Huashan Sword Sect. There is a lot of debate within the industry, but outsiders don't understand why. The editor below will take you to understand the passive balancing and active balancing of iron lithium battery protection boards and what are the differences between them!

　　Principle of lithium iron battery protection board

　　The principle of lithium battery protection board (rechargeable type) requires protection due to its own characteristics. Since the material of the lithium battery protection board itself determines that it cannot be overcharged, overdischarged, overcurrent, short-circuited or charged and discharged at ultra-high temperatures, lithium battery components will always appear with a delicate protection board and a current fuse. The protection function of lithium batteries is usually completed by the protection circuit board and PTC. The protection board is composed of electronic circuits. It accurately monitors the voltage of the battery core and the current of the charging and returning circuit in an environment of -40°C to +85°C. Controls the on and off of the current loop; PTC prevents severe damage to the battery in high temperature environments.

　　The principle of iron lithium battery protection board usually includes control IC, MOS switch, resistor, capacitor and auxiliary device NTC, ID memory, etc. Among them, the control IC controls the MOS switch to turn on under normal circumstances, allowing the cell to communicate with the external circuit. When the cell voltage or loop current exceeds the specified value, it immediately (tens of milliseconds) controls the MOS switch to turn off. Protect the safety of battery cells. NTC is the abbreviation of Negative temperature coefficient, which means negative temperature coefficient. When the ambient temperature increases, its resistance decreases. Use electrical equipment or charging equipment to respond in time, control internal interruptions, and stop charging and discharging. ID memory is often a single-wire interface memory. ID is the abbreviation of Identification, which means identification. It stores information such as battery type and production date. It can achieve product traceability and application restrictions.

　　Understand the passive balancing and active balancing of iron lithium battery protection board

　　Passive equalization generally discharges lithium-iron batteries with higher voltage through resistor discharge, releasing power in the form of heat to gain more charging time for other batteries. In this way, the power of the entire system is limited by the battery with the smallest capacity. During the charging process, lithium batteries generally have a charging upper limit protection voltage value. When a certain battery string reaches this voltage value, the lithium battery protection board will cut off the charging circuit and stop charging. If the voltage during charging exceeds this value, which is commonly known as "overcharging", the lithium battery may burn or explode. Therefore, lithium battery protection boards generally have overcharge protection functions to prevent the battery from overcharging.

　　The active balancing of iron lithium battery protection board is balanced by power transfer, which has high efficiency and small loss. Different manufacturers have different methods, and the balancing current ranges from 1 to 10?A. Many active balancing technologies currently on the market are immature, resulting in battery over-discharge and accelerated battery degradation. Most active equalizers on the market use the transformer principle and rely on expensive chips from chip manufacturers. In addition to the balancing chip, this method also requires expensive peripheral components such as transformers, which are larger in size and higher in cost.

　　The difference between passive balancing and active balancing of iron lithium battery protection board

　　Because the two balancing functions have their own pros and cons, the active balancing function can originally replace the passive balancing function. However, due to the complex structure and high cost, and the high failure rate after the structure is complex, it is in a stalemate with the passive balancing function. People in the industry often wonder why Which equilibrium is better is debated endlessly. In fact, this actually proves that any technology choice must be suitable for the overall conditions. The consistency itself is very good, and the consistency difference is limited during the lifetime, so passive equalization is enough.

　　Passive equalization is suitable for the application of small-capacity, low-series lithium iron battery packs, and active balancing is suitable for the application of high-series, large-capacity power lithium battery packs. In addition to the important balancing function, the balancing strategy behind it is even more important. When the consistency difference of battery cells is within a certain range, the battery power and voltage are positively correlated; but when the consistency of the battery is far worse, that is, when the battery is in a damaged state, the correlation between power and voltage is not so strong. , the basis for balancing at this time cannot be judged solely by the data of voltage. If you are not aware that a battery is damaged below the critical state and still balance based on voltage, it will cause damage to the lithium iron battery, especially active balancing, which will cause greater damage than passive balancing due to its large current.

　　This deserves all manufacturers to be more vigilant, and both balanced methods and balanced strategies need to be paid attention to. According to the Huashan Sword Sect, the purpose of practicing Qi in Qi Buddhism is to control the sword with Qi and unite the heart and sword. In comparison, both active balance and passive balance can be regarded as sword masters, one with light sword and one with heavy sword, and the balanced strategy can be regarded as air master. Only by practicing Qi Sword together can one be able to discuss swordsmanship in the market.

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