Why do lithium-ion batteries need to add a protection board?

2021-08-20 09:12:30 0

Why do lithium-ion batteries need to add a protection board, the principle of lithium-ion battery protection board. The lithium-ion battery protection board, as the name suggests, is to protect the lithium-ion battery. The battery management system BMS is to protect the battery but discharge, but charge, but flow, and has output short-circuit protection. Due to the characteristics of lithium-ion batteries, lithium-ion batteries have a protective plate. Lithium-ion batteries have their own safe discharge and charging and over-current limits. When using lithium-ion batteries, a new protection board is added to keep these values within a safe range. Generally, the voltage of the lithium-ion battery will be controlled within this voltage range after passing through the protection board, which can protect the lithium-ion battery.

Why do lithium-ion batteries need a protective plate?

battery management system BMS

As the lithium ion battery is overcharged, over-discharged, and short-circuited, the battery may be scrapped. The protection board is used for this protection. If you are using it, you must ensure that the battery is not charged, over-discharged, or short-circuited, you cannot use the protection board. . During the use of lithium-ion batteries, every time they are charged, discharged, or short-circuited, the battery life will be reduced. Severe batteries are directly scrapped! If there is no battery management system BMS, the lithium-ion battery will be short-circuited or overcharged, which will cause the battery to drum, and serious leakage, pressure, explosion or fire will occur.

Of course, if the designed lithium-ion battery protection board is not good, it will damage the battery, but the purpose of the protection board is to protect the battery and prevent battery safety problems, so it is still in use, such as lithium-ion batteries. Charging, don't be afraid of time to consider not using the protection board!

The function of the lithium-ion battery protection board is important to protect the battery of the rechargeable battery, maintain the safety and stability of the battery during the charging and discharging process, and play an important role in the performance of the entire battery circuit system.

1. Overcharge protection function: The overcharge protection function means that when the charger reaches a certain voltage (hereinafter referred to as the overcharge detection voltage), the charger is forbidden to continue charging. That is, turn off the overcharged MOS tube and stop charging.

2. Over-discharge protection function: The over-discharge protection function stops discharging when the voltage of the lithium-ion battery is low. Turn off the MOS tube to control over-discharge and prevent it from discharging. This process is just the opposite of the overcharge detection process.

3. Over-current protection function: The over-current protection function stops discharging when large current is consumed. The purpose of this function is to protect the battery and MOS tube, and to ensure the safety of the lithium-ion battery under working conditions. After over-current detection, the battery returns to normal after being separated from the load and can be charged and discharged.

4. Short-circuit protection function: In addition to the control integrated circuit, another important element in the circuit is a MOSFET, which acts as a switching circuit because it directly connects the battery and the external load. The MOSFET is better, the conduction resistance is very small, the internal resistance of the battery is small, the load capacity is strong, and the discharge consumes less power at that time. When your battery is accidentally short-circuited, the shielding layer will automatically close within a few milliseconds and will not be charged, so it is fine if the anode and cathode touch one.

Lithium-ion battery protection board is a series of lithium-ion battery charge and discharge protection; after charging, it can ensure that the voltage difference between the individual cells is less than the set value (usually ±20mV), so as to achieve uniformity of the individual cells Charging effectively improves the charging effect in series charging mode. At the same time, it detects the overvoltage, undervoltage, overcurrent, short circuit, and overtemperature status of each single battery to protect and extend the battery life. Low voltage protection can prevent the battery from being damaged due to over-discharge during the discharge process.