(1) Type identification of the battery
Fixed battery is represented by three parts or four parts, such as GG-360, the first G represents fixed battery, the second G represents tubular positive plate, and 360 represents 360A h; -232, D represents the fixed battery for vehicles, G represents that its positive plate is tubular, and 232 represents 232A•h.
Mobile batteries such as 3CJ-12, S means that the number of single cells is 3, then the voltage is 6V, CJ means silicone battery, 12 means that the ampere hour is 12A.h; another example is 6CJ-180, which means that there are 6 Single battery, the voltage is 12V, CJ means silicone battery, 180 is 180A•h. There are some other models, such as 3-Q-12, which is 6V, starter battery (Q), 12A•h; 6-Q-180, which is 12V, starter battery (Q), 180A•h; QA Indicates dry-load starter battery; M represents motorcycle battery, such as S-MA-12, which is 6V, 12A.h, dry-load motorcycle battery.
(2) How to charge the battery
①Constant current charging method The so-called constant current charging method is a charging method in which the charging current remains unchanged during the charging process. In order to maintain the constant current, the voltage of the power supply must be gradually increased to keep the charging current from decreasing due to the increase of the battery terminal voltage. The disadvantage of this method is that the current at the end of the charging is too large, and the electric energy is uselessly consumed in the electrolytic water.
②Classified constant current charging starts with a larger current (1/10 capacity current), after a period of time, it is switched to 1/20 capacity current charging, and the final current can be smaller (such as 1/30 capacity current) ). This method has high charging efficiency and is good for the life of the battery. The disadvantage is that it is troublesome to constantly adjust the current value.
③Constant voltage charging The so-called constant voltage charging method is a method in which the charging voltage remains unchanged during the charging process. At the beginning of this method, the current is very large, which exceeds the normal charging current, but as the battery terminal voltage rises, the charging current gradually decreases, and finally the current becomes very small, and overcharging will not occur, so you can leave it alone. The disadvantage is that the current is too large at the beginning, which will damage the plate and make the active material fall off. Car teams often use this method to charge, but it cannot perform initial charging and desulfation charging.
③ Pulse charging method To improve the charging speed of the battery without affecting the life and performance of the battery, it is necessary to carefully analyze the charging process of the battery. The main reason for slow battery charging is the existence of concentration polarization and electrochemical polarization in the battery. Concentration polarization is caused by the slow diffusion movement in chemical action. In addition, due to the electrolysis of water during the charging process, H2 surrounds the negative electrode and O2 surrounds the positive electrode, thereby increasing the electrode potential, which is not good for charging. If the charging speed is fast, it is necessary to simulate the actual chemical reaction process in the battery and try to eliminate the factors that are not conducive to charging. Therefore, pulse charging is designed. The steps are: positive pulse charging → pre-break → negative pulse instantaneous discharge (reverse charge depolarization ) → post-break → positive pulse charging. In this cycle, the reverse pulse depth is generally 1.5~3 times the charging current, the pulse width is 150~1000μs, the time between the first and last rest is about 25ms, and the whole process is automatically controlled by a computer.
Using the above-mentioned pulse charger can greatly improve the charging efficiency. Originally, the initial charging time was 50~60h, but now it only takes 5h; the original supplementary charging time is about 13h, but now it only takes 1h, and the pulse charging deepens the reaction depth, increases the capacity of the battery, and removes the effect of sulfation. better. The disadvantage is that the outgassing rate is high, and the scouring force on the active material is large, which makes the active material fall off easily, which affects the life of the battery to a certain extent.
(3) Initial charge of new battery
The quality of the initial charging of a new battery or a newly repaired battery directly affects the life of its capacity, so it must be carried out carefully. The relative density of the electrolyte sulfuric acid is generally 1.251.285, and the relative density is larger when the weather is cold, but it cannot exceed the range casually, because the relative density of sulfuric acid has the best conductivity, low freezing point temperature, and good battery life. After adding the electrolyte, let it stand for 5~6 hours, and then charge when the temperature is lower than 35 ℃ (the electrolyte level should be 15mm higher than the plate); the positive and negative electrodes of the battery are connected to the positive and negative electrodes of the charger during charging. Cannot be reversed. (For more battery charging precautions visit tycorun.com
The charging process is usually divided into two stages. The first stage is charged with C/10~C/15 current. When the terminal voltage reaches about 2.4V, it is switched to C/20 or C/30 charging. The relative density and voltage are stable for 3 hours. So far, the total time is about 60h. During the charging process, the temperature of the electrolyte should be measured frequently. If the temperature rises to 40 °C, the current should be halved. If the temperature continues to rise, the charging should be stopped immediately, and artificial cooling should be adopted. Recharge when it cools down to below 35 °C.
When the initial charging is completed, if the relative density of the electrolyte does not meet the regulations, it should be adjusted with distilled water or sulfuric acid electrolyte with a relative density of 1.2, and then charged for 2 hours after adjustment; if the relative density still does not meet the regulations, it should be adjusted again and charged for 2 hours , until the relative density meets the requirements.
The new battery often fails to reach the rated capacity after the first charge, so it should be charged and discharged for 20h, and then recharged for two or three cycles. The reason why the new battery needs to be charged and discharged is to convert all the PbSO4 generated on the electrode plate of the new battery into active substances during storage, restore the porosity of the electrode plate, improve the contact between the electrode plate and the electrolyte, and make the battery. capable of outputting its rated capacity. Therefore, where conditions permit, the new battery should be charged and discharged.
It is best to use a small current during initial charging, because during the storage process of the battery, a part of the plate may be vulcanized, which increases the internal resistance and is prone to overheating during charging. Charging with a small current can not only make the chemical reaction penetrate into the inside of the plate, but also avoid excessive temperature and have a certain effect on eliminating vulcanization. Determining whether the battery is fully charged is mainly based on three phenomena:
①A large number of bubbles are violently released inside the battery, and the electrolyte is in a “boiling” state;
②The single voltage of the battery reaches 2.7V and remains unchanged for 3h;
③ The relative density of the electrolyte reaches the maximum value, and does not increase for 3h.
This is because with the progress of charging, when the voltage of a single battery reaches 2.4V, almost all of the PbSO4 on the plate has been converted into PbO2 and spongy Pb, respectively. Hydrogen and oxygen are released violently in the form of bubbles, forming a “boiling” state.
Since hydrogen ions combine with electrons slowly on the negative plate, a large amount of hydrogen ions are accumulated near the negative plate, which directly produces a potential difference of 0.33V on the electrode plate of the electrolyte. Therefore, the terminal voltage of a single battery is raised to about 2.7V, and since the lead sulfate on the electrode plate has been completely converted, the relative density of the electrolyte will no longer increase, which means that the battery is fully charged. Silicone batteries do not need to adjust acid and add acid, mainly to control the charging time and observe the voltage.
(4) Dry-charged battery
The main characteristic of dry-charge batteries is that the plates have dry-charging properties. As we all know, the chemical activity of the active material of the positive plate – PbO2 is relatively stable, so the charging performance of the positive plate of the dry-charge battery can be maintained for a long time, but the active material of the negative plate – the charging performance of sponge Pb is not easy. It is maintained because of the large surface area and high chemical activity of spongy lead, which is easily oxidized by oxygen in the air.
In the formation process of dry-charged batteries, repeated charging and discharging should be used to make the formation of active substances profound and thorough, both for the positive and negative plates. However, in addition to this, the negative plate must also solve the problems of easy oxidation and difficult preservation. Therefore, when producing the negative plate, an appropriate amount of antioxidants should be added, such as rosin, У-hydroxyl, β-naphthoic acid, and hydrocarbon-based stearin. Compounds of long-chain fatty acids such as acid and palmoleic acid, lanolin (cholesterol), and high molecular lipids.
(5) The larger the battery discharge current, the lower the temperature, and the smaller the battery capacity.
This is because the larger the current, the faster the chemical reaction, and the active substances on the surface of the plate cannot participate in the chemical reaction, so the actual output capacity of the battery will be reduced. For example, a battery with a rated capacity of 90A h is discharged with a large current of 270A (equivalent to 3 times the rated capacity) when the electrolyte temperature is 30°C. When the single voltage drops to 1.5V, the discharge can only be maintained. 5min, then the output power (ie capacity) at this time is only A h, and its capacity is only 1/4 of the rated capacity.
The lower the temperature, the smaller the capacity of the battery. This is because the lower the temperature of the electrolyte, not only the resistance but also the viscosity of the electrolyte increases, making it difficult for the electrolyte to penetrate into the inner layer of the electrode plate, and the active material in the inner layer of the electrode plate cannot be fully utilized during discharge, so the actual output capacity is also will decrease. For example, taking a battery with a rated capacity of 90A·h as an example, when the electrolyte temperature is -18°C, the battery is discharged at 270A. When the single voltage drops to 1V, the discharge can only be maintained for 2.5min. The power is only 1/8 of the rated capacity. Under normal circumstances, when the electrolyte temperature is lower than 30 °C, for every 1 °C decrease in temperature, the battery capacity will decrease by about 1% when the small battery is discharged, and the capacity will decrease by about 2% when the large current is discharged.
In the formula, У is 0.01 for small current discharge and 0.02 for high current discharge, so when the engine is started with a starter in winter, the discharge current is large, the temperature is low, and the battery capacity is greatly reduced, making people feel that the battery capacity is insufficient.
(6) Internal resistance of the battery
The internal resistance of the battery includes plate resistance, separator resistance and electrolyte resistance, and changes with factors such as charging conditions and temperature. If the internal resistance becomes smaller after charging, the internal resistance becomes larger after discharging; the internal resistance decreases when the electrolyte temperature is high, and the internal resistance increases when the temperature is low; when the battery is normal, the internal resistance is small, and the internal resistance increases when sulfating. Generally speaking, the internal resistance of the battery is small, and the internal resistance of the ordinary 5V battery increases significantly. The main characteristics of excessive internal resistance are that the battery voltage is high during charging, and the temperature of the electrolyte is also high; the voltage is low during discharging, and the discharge capacity also low.
If it is found that the internal resistance of the battery is too large, you should first check whether the plate of the battery is vulcanized. If it is caused by vulcanization, charge it with a small current for a long time to eliminate the vulcanization; if it is caused by poor welding, it should be re-welded.
(7) Self-discharge of battery
A fully charged battery will gradually lose power when left unused, a phenomenon called “self-discharge”. The main reason for self-discharge is that the material is not pure. If there are impurities in the plate material or in the electrolyte, the potential difference between the impurities and the plates, impurities and impurities is directly generated, forming a closed “local battery”. current to discharge the battery.
Since the battery material cannot be very pure, and the positive electrode and the positive electrode grid (Pb-Sb alloy) themselves also constitute a microbattery, slight self-discharge is unavoidable, and if used improperly, it will accelerate the self-discharge. If the electrolyte is impure, when the iron content reaches 1%, the battery will be discharged within a day and night (because iron is a variable valence metal, it is both an oxidizing agent and a reducing agent, which promotes the spontaneous oxidation-reduction inside the battery. When the battery is covered with an electrolyte to make the positive and negative phases conduct, it will cause self-discharge; if the battery is not used for a long time, the sulfuric acid is delaminated, the relative density of the lower part is larger than that of the upper part, and the potential difference between the plate and the lower part is all Can cause self-discharge.
The battery with serious self-discharge can be completely discharged or over-discharged, so that the impurities on the plate enter the electrolyte, then pour out the electrolyte, carefully clean the battery with steamed water, and finally pour in new electrolyte and recharge That’s it.
(8) Charging of long-term storage batteries
For batteries that have been stored for a long time, due to slight vulcanization on the surface of the plates and an increase in internal resistance, the voltage is relatively high at the beginning of charging. This is not really sufficient electricity, but an illusion. After charging for a period of time, with the decrease of PbSO4, the internal resistance will gradually decrease, and its terminal voltage and voltage will drop again. After that, as the charging progresses, the terminal voltage will continue to rise again until the end of charging.
(9) The difference between the charging characteristics of silicone batteries and the charging and discharging characteristics of lead-acid batteries
The charge and discharge characteristics of silicone batteries are basically similar to those of lead-acid batteries, but the charge and discharge characteristics of silicone batteries are not as obvious as those of lead-acid batteries at the end of charge and discharge, but change slowly. A soft characteristic curve. The initial charging time of silicone batteries can be appropriately shortened. The initial charging time of lead-acid batteries is generally about 60~65h, while the initial charging time of silicone batteries is about 55h. Stir evenly, and the silicone battery has no electrolyte layering phenomenon.
For batteries that have been filled with sulfuric acid solution, if you want to change to silica gel electrolyte, you only need to pour out the sulfuric acid after discharging the lead-acid battery, drain it, and then change to silica gel electrolyte.
(10) The battery is overcharged or overdischarged
Normally used batteries do not need to be overcharged, because overcharging will continuously decompose the water in the electrolyte, release H2 and O2, consume electricity uselessly, and the electrolyte will wash the plates for a long time, affecting the life of the battery. However, batteries that have been put on hold for a long time, batteries that have been depleted for a long time, batteries with slight vulcanization, etc. need to be overcharged with a small current for a long time in order to fully activate the active substances of the battery and make the battery capacity sufficient.
When using the battery, generally do not over-discharge, and stop discharging according to the specified termination voltage, otherwise the battery will often lose power, which will cause the plate to vulcanize. , so that the battery is always kept in a fully charged state, which will prolong the service life of the battery.
For lead-acid or silicone batteries, the termination voltage of full discharge when used as an energy storage battery is generally specified as >1.75V per single voltage (100% capacity discharge). The discharged battery must be recharged in time (not more than 20h), otherwise it will promote the vulcanization of the plate.
(11) Float charging
Floating charging is a mode of operation of the battery (or battery pack), generally running in parallel with the floating charger (or solar engine, etc.) after the battery is fully charged, the DC load current is supplied by the floating charger, and the floating charger also When charging, when the external DC load suddenly increases (or the light suddenly stops), the battery will supply power to ensure the needs of the outside world. If the external load is normal, the battery will start to run in parallel with the floating charger. This operation mode is floating charging. .
The floating charging current during floating charging is generally in the range of very small [0.05~5mA/(A·h)], which can be expressed by an empirical formula (for reference only):
In the formula, Ifc is the output current of the floating charge silicon rectifier device; C10 is the rated capacity of the battery (C5 for the nickel-cadmium battery); Ijc is the constant load current of the DC system.
Because the size of the floating charge current is related to the capacity, age, and grid composition of the battery, the size of the floating charge voltage is generally also specified. At the beginning, China quoted foreign experience and stipulated that the float voltage was between 2.1 and 2.2V. Now, according to practical experience, it is considered that it is more appropriate to specify the float voltage in the range of 2.15 to 2.17V. If the float voltage is too low, the capacity of the battery will decrease over time; if the float voltage is too high, it is easy to overcharge and damage the plates. These problems are often encountered.
In a word, careful and meticulous maintenance of the battery is the key to affecting the electrical performance and service life of the battery. The quality of use and maintenance, that is, whether it can be used in strict accordance with the requirements of the product instruction manual, will affect the electrical performance and service life of the battery. , far more significant than the impact of product structure and production level.