The principle of lithium battery protection board, what are the advantages of lithium battery protection board

2021-08-16 10:13:12 0

The principle of lithium battery protection board, the advantages of lithium battery protection board. The application of lithium batteries in all walks of life has been increasing. Lithium battery protection board, as the name implies, is to protect lithium batteries. The three basic functions of lithium battery protection boards are short-circuit protection, overcharge protection and overcharge protection.放保护。 Put protection. To maximize the safety, life and performance of your lithium battery, you need an accessory to ensure that the lithium battery is short-circuited and overcharged and over-discharged.

Introduction to the principle of lithium battery protection board battery management system BMS

The reason why lithium battery (rechargeable type) needs 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, and ultra-high temperature charging and discharging, the lithium battery components of the lithium battery will always appear with a delicate protection board and a current fuse. The protection function of lithium battery is usually completed by a protection circuit board and current devices such as PTC. The protection board is composed of electronic circuits, which can accurately monitor the voltage of the battery cell and the charging and discharging circuit at all times under the environment of -40°C to +85°C. Current, timely control the on and off of the current loop; PTC prevents severe damage to the battery in high temperature environments.

Ordinary lithium battery protection board battery management system BMSs usually include control ICs, 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 under all normal conditions to make the cell and the external circuit conduct, and when the cell voltage or loop current exceeds the specified value, it immediately controls the MOS switch to turn off to protect the cell’s Safety.

When the protection board is normal, Vdd is high, Vss and VM are low, DO and CO are high. When any parameter of Vdd, Vss, VM is changed, the level of DO or CO will be Changes.

Due to the chemical characteristics of lithium batteries, during normal use, the internal chemical positive reaction of the mutual conversion of electric energy and chemical energy, but under certain conditions, such as overcharging, overdischarging and overcurrent will cause the internal battery A chemical side reaction occurs. When the side reaction is intensified, it will seriously affect the performance and service life of the battery, and may produce a large amount of gas, which will cause the internal pressure of the battery to rapidly increase and then explode, causing safety problems. Therefore, all lithium batteries need a protection The circuit is used to effectively monitor the charging and discharging status of the battery, and to shut off the charging and discharging circuits under certain conditions to prevent damage to the battery.

Advantages of lithium battery protection board

1. Overcharge protection to prevent damage to the lithium battery pack caused by overcharge.

2. Over-discharge protection to prevent over-discharge from declining battery life.

3. Over-current and short-circuit protection is safer and more reliable during the use of lithium batteries.

4. It is small in size and can be applied to a variety of lithium battery packs.

The biggest difference between lithium batteries and traditional nickel-cadmium and nickel-metal hydride batteries is that their negative electrode material uses metal lithium. Lithium ions themselves are relatively active ions in the chemical periodic table, which makes the lithium battery itself and Compared with nickel-cadmium and nickel-metal hydride batteries, the stability is relatively poor. If a line failure occurs, it will easily cause serious consequences. Therefore, lithium batteries must use lithium battery protection boards to enhance the safety of their lines. This is why a lithium battery protection board must be added to the lithium battery.

Although the lithium battery protection board plays a protective role, in the working state, the protection board itself is also equivalent to a load, and it also consumes voltage; therefore, the external consumption of the lithium battery is larger than other batteries. In layman's terms, lithium batteries consume more power than batteries of the same capacity when working, so the life cycle of lithium batteries will be shortened in disguise.

So everything has two sides, and there are good and good things. Do not think that the lithium battery protection board is omnipotent. It also has its own shortcomings. When using a lithium battery, in addition to meeting the hardware requirements, it needs to be manipulated properly, so that the performance and life of the lithium battery can be obtained. Maximize utilization.