The principle of lithium battery protection board, can the lithium battery be charged without the protection board?
The principle of lithium battery protection board, can the lithium battery be charged without the protection board? As the application demand for electronic products is getting higher and higher, the demand for lithium batteries is also getting higher and higher. Lithium batteries are used in various electronic products as a battery with relatively large electric storage. However, there is a product that can effectively prevent lithium batteries from overcharging, overdischarging and short-circuiting of internal circuits. It is a lithium battery protection board.
Lithium battery protection board
The lithium battery protection board is a protection for the charging and discharging of the lithium battery pack in series; when fully charged, it can ensure that the voltage difference between the single cells is less than the set value (generally ±20mV), so as to realize the equal charge of the single cells of the battery pack , Which effectively improves the charging effect in the series charging mode; at the same time, it detects the overvoltage, undervoltage, overcurrent, short circuit, and overtemperature status of each single battery in the battery pack to protect and extend the battery life; A single-cell battery is used to prevent damage to the battery due to over-discharge.
Principle of Lithium Battery Protection Board
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 boards 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.
The main function of lithium battery protection board
Generally, it is required that Control (IC) detect the voltage of the control cell and the working current and voltage of the charging and discharging circuit at -25℃～85℃. Under all normal conditions, the C-MOS switch tube is turned on, so that the cell and the protection circuit board are in contact with each other. Normal working state, and when the cell voltage or the working current in the loop exceeds the preset value of the comparison circuit in the control IC, the CMOS is turned off within 15-30ms (different control ICs and C-MOS have different response times) , That is, close the battery discharge or charging circuit to ensure the safety of the user and the battery.
Is it okay to charge the lithium battery without the protection board?
As to why some people have the idea that lithium batteries do not need to protect the board, a big reason lies in the emergence of lithium iron phosphate batteries. Because there is news that lithium iron phosphate batteries are not afraid of overcharging or over-discharging, there has been the argument that lithium batteries can be used without a protective plate.
However, so far, no manufacturers have publicly declared that they do not use lithium battery protection boards. Since everyone has disputes on this issue, let us first return to the protection board itself, back to its definition and use, so that we can have our own views on whether the lithium battery can be used without the protection board.
The lithium battery protection board, as the name suggests, is used to protect the lithium battery. The function of the lithium battery protection board is to protect the battery from over-discharge, over-charge, and over-current, as well as output short-circuit protection.
Those who think that lithium batteries do not need a protection board feel that if the lithium battery is not connected to the protection board, it will be broken, and the protection board will discharge the lithium battery that has not been used for a long time. Obviously, I don’t know much about the role of the protective plate. The role of the protective plate for the lithium battery is equivalent to an additional protective barrier, and the role of the protective plate is to ensure the safety of the lithium battery and extend the service life. Without the protection board, not only the life span is difficult to guarantee, but it is also very dangerous.
Therefore, when the lithium battery is completely immune to the effects of overcharge, overdischarge, etc., when the lithium battery itself can completely replace the role of the protection board, the lithium battery may not need the protection board, but at this stage, the lithium battery is still Need to protect the board.
The lithium battery protection board is to protect the battery from overcharging, overdischarging, short circuit and other problems. Since the protection board is so important to the safety of the battery, it is best to use the protection board to avoid unnecessary damage to the battery.