- Jan 10, 2018 -
What do the positive and negative pulses of a pulse charge mean?
Pulse charging is divided into negative pulse, positive pulse, positive and negative pulse
That is, when charging, discontinuous discharge of the battery pulse. In theory, when charging, the polarization voltage in the battery will hinder its own charging, especially in the later stage of fast charging, which will increase the outgassing rate and temperature rise. The magnitude of the polarization voltage will change with the change of charging current. When stop charging, resistance polarization disappeared, concentration polarization and electrochemical polarization also gradually weakened, and if provided a discharge channel for the battery to make it reverse discharge, then the electrochemical polarization will disappear quickly, and the temperature inside the battery will also be reduced by discharge. Therefore, in the battery charging process, timely suspension and charging, and proper discharge of the discharge pulse can eliminate various polarization voltages quickly and effectively, thereby improving charging speed. Therefore, to reduce the loss of water, reduce the temperature and reduce the voltage limit of charging, and fast charging, the negative pulse charging is the first choice of many manufacturers at present. However, it has little effect on vulcanization and equilibrium, and has large energy consumption, and it is not an ideal charging mode. The so-called negative pulse of some manufacturers is just intermittent charging, or when the charging current is interrupted, the battery really discharge little, the effect is small, and the propaganda and speculation is large.
High voltage and large current moment is a major role for curing to pulse, the battery for curing and repairing effect of reduced capacity significantly, the main theory of job market battery repair machine on the way to the positive pulse vulcanization mechanism: the reaction of lead sulfate and lead sulfate the negative battery discharge, lead sulfate just generated by ion soluble and conductive problems such as not timely to charge reduction, lead sulfate molecules combine to form larger molecules will lead sulfate crystal insulation insoluble, the battery can not be formed sulfate - sulfide.
In solid physics, any insulating layer can be penetrated under high enough voltage. Once the insulating layer is broken, the lead sulphate will be conductive. The lead and sulfuric acid will be regenerated under the strong redox action of the current to participate in the electrochemical reaction. If the pulse width is short enough, the microcharge can not be formed at the same time when the crystallization of the heavy lead sulfate is worn. In this way, the pulse can be eliminated under the condition of lossless battery.
The best time to realize pulse vulcanization is the late charging period, that is, the three stage trickle holding section, and the high voltage pulse current is relatively less absorbed and diverted. Because the narrow pulse width and the diversion of other substances, the energy that is used to remove sulfidation is limited. The short time pulse de sulfurization repair effect is limited, and the long-term use of pulse repair charger will be better.
At present, many manufacturers have launched pulse type charger, the incomplete detection has small amplitude current pulse (<2a pulse width (seconds) time (a short pulse timing manufacturers in Guangdong about 60 seconds), and many claimed that the pulse charger tested could not find the pulse waveform, pure speculation and deceive consumers.
For positive and negative pulses, high frequency pulses (8.333khz frequency conversion pulse), or high cost, or technical reasons (effective and effective pulse charger to eliminate noise and interference when pulse is very difficult), it is still in the concept stage, and it is hard to find products in the market. Once the market is also because the price is high, the user is difficult to accept, push but not wide.
Because nickel cadmium battery is easy to polarize during regular charging, constant or constant current charging will cause the electrolyte to generate hydrogen and oxygen gas continuously, and its oxygen will penetrate into the negative electrode and cadmium plate to generate CdO when the internal pressure is high, resulting in the decrease of effective capacity of the plate. The charging and discharging method is usually used in pulse charging, that is to say, charge for 5 seconds and put it for 1 seconds. This charging process of oxygen in the discharge pulse will be reduced to most of the electrolyte, the gassing rate is greatly reduced, reducing the gas evolution can make the concentration polarization and ohmic polarization naturally are eliminated, thus reducing the battery internal pressure, the pulse of the next stage constant current charging more smoothly, so the lead-acid battery can absorb more power.
Intermittent pulse makes the lead-acid battery have sufficient chemical reaction time, thereby reducing the volume of gas in lead-acid battery during charging and improving the acceptability of lead-acid battery charging current.
The pulse charge method is charged for 5 seconds, and the charge is stopped for 1 seconds.