Forklifts use lithium batteries, these issues must be known!
Forklift lithium battery packs may pose serious hazards if there are issues with battery cell selection, pack process, charger, protective board, wiring connections, or improper use!
The battery pack cannot be charged
The reason why the battery pack cannot charge during charging can be divided into the following reasons: reverse connection of the charger or charger failure; Protection board protection not restored or protection board failure; The battery pack is disconnected from the outside of the electrical appliance.
When dealing with the above adverse phenomena, check in sequence: whether the charger is connected in reverse, whether the positive and negative plugs of the battery pack are connected in reverse; Restart the electrical appliance to remove the protection board and measure whether the MOS transistor on the protection board has a driving voltage; Check if the wiring connections are loose or disconnected.
The battery pack cannot discharge
There are several reasons why the battery pack cannot discharge normally during use: low battery pack voltage protection board or controller protection; Damage to the protective board or controller; Reverse the polarity of the discharge; The circuit is disconnected or the switch is not turned on.
To address the above issues, measures can be taken such as charging the battery pack, searching for protective boards or wiring connections to solve them.
The battery pack is not fully charged
During the cyclic use of the battery pack, charging stops before the overall cut-off voltage of the battery pack is reached. This situation is due to inconsistent single string battery levels or capacities, where the battery with high or low capacity is first fully charged and protected by the protection board, causing the charging process to stop before the batteries in other strings are fully charged.
In this situation, a balanced charger can be used to recharge the battery pack to keep the voltage of each string consistent. If there is a large difference in capacity, the battery with the large difference must be replaced. But the main thing is that before assembling the battery, it is necessary to perform capacity testing and matching of the battery cells, otherwise it will be troublesome to disassemble them again if a single string becomes outdated.
Short range
The battery pack drains quickly when in use, and the reasons for this situation include: the battery is not fully charged; There is a large difference in voltage capacity between single strings; The micro short circuit or self discharge of the battery pack can cause the battery pack to be fully charged before being consumed.
To address the above issues, the battery pack can be recharged or defective cells can be replaced.
Low voltage battery pack
The overall voltage of the battery pack is only half of the nominal voltage or negative voltage, which usually occurs when the battery pack is just assembled. The reason for this is that the positive and negative poles of the battery pack are connected incorrectly or some batteries are not fully connected; If the battery pack is normally charged but immediately experiences low voltage after being idle or used for a period of time, this situation may be due to the battery self discharging or a slight short circuit in the battery pack.
If the nominal voltage is low or negative, the wiring must be reconnected correctly. If there is a low voltage immediately after being fully charged, the faulty battery needs to be replaced.
High temperature of battery pack
The temperature of the battery pack is abnormally high and hot during charging or discharging, which may be due to the presence of high internal resistance batteries or micro short circuits in the battery pack, resulting in an increase in temperature during charging and discharging.
Long term high-temperature operation of battery packs is very dangerous, and in such cases, it is necessary to replace defective batteries or repair micro short circuit circuits.
Short cycle life of battery pack
The lifespan of the battery pack expires within the promised usage time, which is due to poor consistency of the battery pack or particularly poor performance of individual series connected batteries, resulting in insufficient charging and discharging of the battery pack.
In this situation, only defective battery cells can be selected and replaced again
The battery pack suddenly stops working during use
The sudden stop of the battery pack during use may be due to the battery being discharged and reaching the lower limit voltage of the protection board or controller, causing the protection board or controller to stop working; Or if the continuous working current is too high (such as when an electric vehicle is starting under heavy load or climbing), exceeding the design protection current of the protection board or the continuous current of the controller, causing the protection board or controller to stop working, this will cause the battery pack to suddenly stop working.
The above situation can be solved by charging the battery pack, restarting the electrical appliances, adjusting the parameters, replacing the protection board, or using the controller.
Battery pack leakage and fire
The battery pack may overflow with liquid during use, or suddenly catch fire during use. This situation is not common, but it can be very dangerous when it occurs. Leakage may also lead to fire and explosion, as the spilled electrolyte lithium hexafluorophosphate is an organic solvent with a very low ignition point. The reason for this is that the moisture in the battery cell is not completely dried, resulting in side reactions inside the cell that cause gas to rush open the safety valve. The sealing of the battery cell cap is poor and the protection is poor. The cause of the fire may be a short circuit or leakage inside or outside the battery, or the battery pack being close to the fire source and the packaging material not being fire-resistant.
If the battery is only leaking, replace the leaking battery. If the battery pack catches fire, it must be covered with a fire extinguisher, fire sand, etc. Do not use water, clothing, etc. to extinguish the fire because water is a conductor and clothing is flammable.
Explosion of battery pack
The battery pack may explode when it is stationary or in use, which is rare to occur like a battery pack catching fire, but the consequences are serious. The reason for the occurrence is also due to prolonged external or internal short circuits. An external short circuit is equivalent to an instantaneous discharge of ultra-high current, exceeding the limit of the cell protection board, causing the gas generated inside to instantly spray out, which is very dangerous. Internal short circuit and poor sealing effect of the diaphragm can also cause explosions.
For preventing external short circuits, protective boards can be used to avoid them. Protective boards have short-circuit and overcurrent protection functions to completely eliminate this risk. However, for internal short circuits in batteries, qualified battery cells from reputable manufacturers must be selected to eliminate them.
As mentioned above, it is necessary to ensure the safe use of the battery pack.
