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Differences in nickel-hydrogen, cadmium nickel batteries and lithium ion batteries

Differences in nickel-hydrogen, cadmium nickel batteries and lithium ion batteriesNow there are many models of rechargeable batteries on the market, only 500mAh, 600mAh, 700mAh, 850mAh, 1200mAh and 1300mAh, etc. Different capacity batteries require different charging currents, some general-purpose chargers in the market are mostly designed for early 500mAh and 600mAh batteries, and the charging current is between 60 and 70 mA. At present, the battery in the market is mainly based on 18650 lithium batteries.
(1) Weight
From the voltage of each unit battery, the nickel-hydrogen battery and the nickel-cadmium battery are 1.2V, while the lithium ion battery is 3.6V, the voltage of the lithium ion battery is 3 times the nickel-hydrogen and cadmium nickel battery. Further, the weight of the lithium ion battery of the same type is almost equal to the cadmium nickel battery, and the nickel-hydrogen battery is relatively heavy. However, the lithium-ion battery is 3.6V due to the output of the same voltage, and the number of single cells can be reduced by 2/3, thereby reducing the weight and volume of the battery pack after molding.
(2) Memory effect
Cadmium nickel batteries have a memory effect, so regular discharge management is required. This periodic discharge management belongs to passive management in a fuzzy state, even in the case of unspecified amount of cadmium nickel battery load (discharge each time, discharging the cadmium nickel battery or uses several times, all due to cadmium nickel battery production Vendors and use are different.). This cumbersome discharge management is unavoidable when using cadmium nickel batteries. Relatively, the lithium-ion battery has no memory effect. It is very convenient and simple in use, and it is not necessary to consider how much the secondary battery residual voltage can be charged. The charging time can naturally be shortened.
The memory effect is a big enemy of the rechargeable battery. It is generally considered to be caused by long-term incorrect charging, which can make the battery early. The memory effect can make the battery unable to charge, and there is a full charge, and the phenomenon is finished. The method of preventing memory effects from the battery is to strictly follow the principle of "sufficient light", that is, it is best to put the residual amount of electricity in the battery before charging, and it is sufficient when charging. Usually, cadmium-nickel-nickel batteries are prone to memory effects, so they should pay special attention when charging; the nickel-hydrogen battery has no memory effect, but it is best to follow the principle of "sufficient charging", which is a lot of charger to provide discharge attachment function. s reason. For batteries that cause a capacity drop due to memory effects, it can be repeated several times by a method of sufficient and then one-time light, and most of the batteries can be repaired.
(3) Self-discharge rate
Cadmium nickel battery is 15% / month ~ 30% / month, the nickel-hydrogen battery is 25% / month to 35% / month, and the lithium-ion battery is 2% / month to 5% / month. In the above three batteries, the self-discharge rate of the nickel-hydrogen battery is the largest, while the self-discharge rate of the lithium ion battery is minimized.
(4) Charge mode
Charging problems of the rechargeable battery has always been the focus of people concerned, correct, and good charging method ensures the life of the battery. Recommended charging methods recommended by the rechargeable battery have a variety of diverse, different charging methods have different requirements for the charging lines, and naturally affect the production cost of the charger. The relationship between the battery charging time and the charging current is that the battery capacity is divided by the charging current to obtain a charging time, considering the loss during the charging process, so the resulting charging time is multiplied by 1.2.
The most common simple charging method of cadmium nickel and nickel-hydrogen batteries is 10% C constant current charging, and it is called "slow charge", ie, according to battery capacity, the charging current is determined. If a battery is a battery having a capacity of 500mAh, its suggestion charging current is 50mA; another battery is a battery having a capacity of 1300mAh, its proposed charging current is 130mA. Continuous charging under this current can be considered as a battery. Although it is recommended to use constant current charging, the requirements are not strict, and the current allows for large fluctuations, so the charger structure made in this method is very simple, generally only need to use the transformer to convert 220V power to appropriate low voltage, and adopt a rectifier diode Rectify, capacitor uses current limiting resistance limit stream and is equipped with light-emitting diodes, etc. Most of the independent conventional chargers on the market use this way, but the shape is different. Although "slow charging" is relatively simple, it is necessary to wait for more than 10 hours. To this end, battery manufacturers also allow users to charge the battery with 30% C at a current, called "fast charge" ". With the "fast charge" mode, there is a slight damage to the battery in theory. Therefore, most of the conventional chargers have "fast charge" and "slow charge" two gears, and users do not often use "fast charge" mode.
In many cases, users need to quickly, effective, safe charging the battery, quickly charging, you need to use larger current. The battery will generate the polarization effect during the large current charging, so that the battery is fully charged, and if the battery is charged, if it is not stopped, the battery will be quickly generated, and the battery can cause the battery to burn and explode. Therefore, the fast charger is required to have a battery full of self-stop, but also solve the polarization effect, so that the charging process is efficient and safe. Early fast charger uses a simple timing charging method, such chargers have strong targeted battery, and the charging effect is not satisfactory. Modern charger uses a dedicated charging control integrated circuit to charge the battery with high-frequency pulse current to solve the polarization effect. Detect different parameters according to the characteristics of different batteries to accurately determine whether the battery is full, and provides temperature protection and other protection measures and Additional function such as discharge before initial charging. However, this charger structure is more complicated, the cost is also relatively high, generally used for high-end communication equipment and electrical appliances such as mobile phones, walkie-talkies.
If you want to charge a larger capacity battery, you need a longer charging time. The actual charging current can be measured first using a multimeter current, and then the battery capacity is divided by the charging current, and then multiplied by the coefficient 1.2 can obtain the specific charging time. For nickel-hydrogen batteries above 1000mAh, you can try the fast pocket of ordinary chargers because this gear current is large, and the actual charging current is measured with a multimeter current. The value should be close to the 10% C charge required by the prefilmium hydrogen battery. Current. In fact, many so-called nickel-hydrogen batteries in the market are only a conventional charger that is large with a large charging current.

The charger sold in the market mainly has two kinds of special types and universal types. The so-called special model is an charger that is equipped with an integrated battery pack for an electrical appliance, typical is a mobile phone supporting charger. When choosing such a charger, the original supporting product is generally suitable, one is the model to the mouth (a dedicated charge adapter), the charging voltage corresponds; the second is that most such charger use high-efficiency fast charge, high work efficiency. The biggest advantage of some special chargers in China is inexpensive, but because various manufacturers use different internal lines and different charging methods, many products use simple electronic lines to reduce costs, and the charging effect is not good, and there is no international Recommended charging method. When selecting a dedicated charger, a dedicated charger that is supported with the battery pack should be used, it is best to have discharge and self-stop products, and have a liquid crystal charging process indication and automatic fast charging function. Universal charger needs to be charged independently of the battery one section. Most of the general-purpose charger in the market is a product of 10% C-charging current. Some have an additional function such as electricity test.

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