power battery equalization managemen

Hey, you know what ? When we talk about electric vehicles, power tools and other equipment using power batteries, there is a key technology that plays a huge role behind it, that is, power battery equalization management.

The power battery is usually composed of several single cells connected in series and parallel. Imagine that this is like a team, each single cell is a member of the team. If the voltage between these ' players ' is not balanced, it is troublesome ! The single cell with the lowest voltage will be like a dragging team member, affecting the performance of the entire battery, so that the entire battery pack can not play its due strength.

So what can be done? Don't worry. Smart engineers have introduced battery equalization technology. This technology is like a super coach, using various means to make each single battery in the battery pack as consistent as possible in terms of voltage, capacity, and operating state, so as to optimize battery performance and maximize its lifespan.
I. Definition and Significance of Battery Equalization

1. Definition: Battery equalization refers to the use of specific technologies and means to ensure that each single battery in the battery pack is on the same level, just like making a group of runners maintain the same speed and rhythm.
2. Significance:
(1) Improve the performance of the battery pack: Through equalization treatment, the degradation of individual battery performance that leads to a decline in overall performance can be avoided, allowing the battery pack to always operate efficiently.
(2) Extend the battery life: Reducing the differences in voltage and capacity among battery cells and lowering the internal resistance is like giving the battery a "maintenance", effectively extending its service life.
II. Methods of Battery Equalization

1. The equalization function of BMS (Battery Management System): BMS is like the "housekeeper" of the battery pack. It reduces inconsistencies and improves the available capacity and extends the lifespan by adjusting the energy distribution among battery cells. Currently, there are mainly two methods, passive equalization and active equalization.
2. Passive equalization:
(1) It is also known as energy-dissipative equalization, and its working principle is like letting out the "excess air" of the battery cell that stands out. When the charge of a certain battery cell is higher than that of other cells, the energy of this high-energy battery will be dissipated as heat through the parallel resistor, achieving equalization with other battery cells.
(2) Passive equalization technology is simple and has a low cost, and is widely used in various battery systems. However, it also has drawbacks. The energy loss is relatively large, and the consumed energy is turned into heat and not effectively utilized.
(3) When designing a passive equalization system, the equalization current is usually controlled at a very low level (about 100 mA), and the equalization and acquisition processes share the same wire harness and are carried out alternately. Although this reduces the system complexity and cost, it also brings the problem of low equalization efficiency, and it takes a long time to see obvious results.
(4) The implementation methods of passive equalization mainly include fixed shunt resistors and switched shunt resistors. The fixed shunt resistor is like a safety valve that is always connected, preventing the battery from overcharging; the switched shunt resistor is like a precisely controlled valve that eliminates excess energy by controlling the opening and closing of the switch.
3. Active equalization:

(1) Active equalization is a more efficient energy management method, like a "porter", transferring the energy in the battery cell with a higher capacity to the battery cell with a lower capacity, not only achieving voltage equalization but also improving the overall energy utilization rate.
(2) During the charging process, when a certain battery cell reaches the upper limit of the working voltage first, the BMS will start the active equalization mechanism, identify the battery cell with a relatively low capacity, and transfer the energy in the high-voltage battery to the low-voltage battery through a carefully designed equalizer circuit, just like giving an "extra meal" to the "hungry" battery.
(3) Active equalization usually involves complex algorithms to calculate the specific amount of energy transfer, while passive equalization relies more on precisely controlling the switch time to consume excess energy.

Whether it is passive equalization or active equalization, both are indispensable parts of the BMS and play an important role in improving the available capacity of the battery pack, extending its service life, and enhancing the overall efficiency of the system. During the equalization process, the system will continuously monitor the parameter changes of each battery cell to ensure that the equalization operation is both effective and safe. When the differences among battery cells reach the preset acceptable range, the system will end the equalization operation.

By choosing a suitable equalization method, strictly controlling the equalization speed and degree, and effectively managing the heat generated during the equalization process, the performance and service life of the battery pack can be greatly improved. Let's pay attention to power battery equalization management technology together and contribute to more efficient and durable energy utilization!