Balancing function of 6F22 carbon battery protection board
Balancing function of 6F22 carbon battery protection board - Balancing
principle of 6F22 carbon battery protection board Commonly used balancing
charging technologies include constant shunt resistance balancing charging,
on-off shunt resistor balancing charging, average battery voltage balancing
charging, switched capacitor balancing charging, and buck converter balancing
Charging, inductor equalization charging, etc.
Balancing principle of 6F22 carbon battery protection board:
6F22 carbon battery protection board balancing principle Commonly used
balancing charging technologies include constant shunt resistance balancing
charging, on-off shunt resistor balancing charging, average battery voltage
balancing charging, switched capacitor balancing charging, buck converter
balancing charging, inductor balancing charging, etc. When charging a group of
lithium batteries in series, each battery should be charged evenly, otherwise
the performance and life of the entire battery group will be affected during
use. However, the existing single-cell 6F22 carbon battery protection chips do
not contain the balanced charge control function. The balanced charge control
function of the multi-cell 6F22 carbon battery protection chip requires an
external CPU; it is realized through serial communication with the protection
chip (such as I2C bus), which increases the cost. This increases the complexity
and design difficulty of the protection circuit, reduces the efficiency and
reliability of the system, and increases power consumption.
According to the needs of the application, the balancing principle of 6F22
carbon battery protection board can realize protection and equal charging of
power 6F22 carbon battery packs of any structure and voltage level after
changing the protection chip model and series number, and the power level of
switching devices and energy consumption components in the circuit. .
As a kind of battery with relatively large power reserve, 6F22 carbon
battery is used in various computer rooms, communication base stations, data
centers and other fields. The 6F22 carbon battery protection board has the
function of protecting the battery and preventing the battery from
overcharging.
Passive balancing and active balancing of 6F22 carbon battery protection
board:
The battery itself still has usable capacity, but the battery system cannot
continue to perform as it should due to the imbalance between the cells and the
limit of the safe voltage set to protect the battery. In addition, the service
life of the battery in the vehicle is shorter than the life of the vehicle
itself. Even if the vehicle has not reached the end of life, the battery must be
replaced to meet the power performance. However, the cost of replacing batteries
is quite high, which has largely restricted the development of electric
vehicles.
The main cause of battery imbalance is temperature. Generally speaking,
when the ambient temperature of a lithium-ion battery is 10°C higher than its
optimal temperature, the life of the lithium-ion battery will be reduced by
half. Since the number of series connections in the vehicle-mounted battery
system is very large, generally between 88 and 100 series connections, and its
capacity is generally between 20 and 60kWh, the different loading positions of
each string of batteries will produce a temperature difference. Even within the
same battery box, there will be a temperature difference due to different
locations and battery heating. This temperature difference will have a
significant negative impact on battery life, causing the battery to become
unbalanced, resulting in reduced cruising range and shortened cycle life. It is
precisely because of these problems that the capacity of the entire battery
system cannot be fully used, causing battery system losses. Slowing down such
system losses will greatly extend the service life of the battery system.
As shown in Figure 1, the initial capacity of the battery system is 100%.
During use, the battery will gradually decay due to various reasons (mainly
temperature). This is a characteristic of lithium batteries. This part of the
attenuation cannot be restored through equalization. The main reason for the
decrease in system capacity is system loss caused by imbalance of battery
capacity. System loss does not mean that the capacity of all batteries is
reduced, but that the battery system cannot be used even if it has capacity due
to imbalance.
Under normal circumstances, when the battery capacity drops to 70% to 80%,
the battery will be replaced to maintain the cruising range. The longer the
battery capacity remains above 70%, the lower the cost of the electric vehicle
will be. Without balancing and general passive balancing technology, the
capacity of the battery system will drop below 70% in less than 3 years (full
discharge once a day). A well-done passive equalization can barely maintain the
battery capacity at 70%. In sharp contrast, well-done active equalization can
minimize system losses. Such active balancing can effectively reduce system
losses caused by capacity imbalance, thereby extending the service life of the
battery system, delaying the replacement period of the battery system, and
increasing the cruising range. Passive equilibrium and active equilibrium
The 6F22 carbon 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 6F22 carbon 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.
1. Passive equilibrium
Passive equalization generally discharges batteries with higher voltages
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
6F22 carbon 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 6F22 carbon battery may burn or explode. Therefore,
6F22 carbon battery protection boards generally have overcharge protection
functions to prevent the battery from overcharging.
During the charging process, the No. 2 battery is first charged to the
protection voltage value, triggering the protection mechanism of the 6F22 carbon
battery protection board and stopping the charging of the battery system. This
directly causes the No. 1 and No. 3 batteries to be fully charged. The full
charge capacity of the entire system is limited by the AA battery, which is a
system loss. To increase the capacity of the battery system, the 6F22 carbon
battery protection board balances the battery during charging. As shown in
Figure 3, after the equalization is started, the 6F22 carbon battery protection
board will discharge the No. 2 battery, delaying the time for it to reach the
protection voltage value. In this way, the charging time of the No. 1 and No. 3
batteries will be correspondingly extended, thereby improving the entire battery
system. of power. However, 100% of the discharged power of the No. 2 battery is
converted into heat release, causing a lot of waste (the heat dissipation of the
No. 2 battery is a loss of the system and a waste of power).
In addition to overcharging having a serious impact on the battery,
overdischarging can also cause serious damage to the battery. Similarly, the
6F22 carbon battery protection board has over-discharge protection function.
During discharge, when the voltage of battery No. 2 reaches the discharge
protection value, the protection mechanism of the 6F22 carbon battery protection
board is triggered and the system is stopped from discharging. This directly
results in the remaining battery capacity of batteries No. 1 and No. 3 not being
fully used. After balanced startup, the system will be improved. Over
release.
The advantages of passive balancing are low cost and simple circuit design;
the disadvantage is that the balance is based on the lowest remaining battery
capacity, which cannot increase the capacity of batteries with low remaining
capacity, and 100% of the balanced power is wasted in the form of heat.
2. Active balancing
Active balancing uses power transfer to balance, 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, causing batteries to over-discharge and
accelerating 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.
Each 6-string battery is a group, and the total power of the 6-string
battery is transferred to the battery with a smaller capacity. Inductive active
balancing is based on physical conversion and integrates a power switch and a
micro-inductor. It adopts a two-way balancing method to balance the battery
through charge transfer between similar or adjacent batteries, and can be used
regardless of whether the battery is discharging, charging or resting. For
equalization, the equalization efficiency is as high as 92%.
The working principle of discharging and charging is shown in Figure 6 and
Figure 7. Battery No. 2 transfers power to batteries No. 1 and No. 3. Efficient
charge transfer keeps the voltages of the three batteries in a balanced state
during charging, so that all batteries can be fully charged. The 6F22 carbon
battery protection board can also balance the battery when discharging. Battery
No. 1 and Battery No. 3 transfer power to Battery No. 2, and the voltages of the
three batteries are always discharged in a balanced state, so that all batteries
can be used up.
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