1. Voltage of the batteryThe battery of the battery is 2V, and the actual voltage is changed as charging. At the end of the charging, the voltage is 2.5 to 2.7V, slowly down to a stable state of about 2.05V. If the battery is used as a battery, the voltage is quickly dropped to about 2V when the discharge is started, and then slowly decreases in 1.9 to 2.0V. When the discharge is close to the end, the voltage quickly drops to 1.7V; when the voltage is below 1.7V, it should not be discharged, otherwise the polar panel is damaged. After the use, the battery voltage can rise to 1.98V.
2, battery capacity
The concept of the battery capacity (c): the lead-acid battery in a fully charged state is discharged to the predetermined termination voltage at a certain discharge, referred to as the battery capacity, and is expressed in symbol C. Common units are ampere hours, referred to as safety (a? H). The discharge rate is typically indicated at the lower corner of C, which indicates the time (h) of the type of battery to the set voltage in the class battery to a set voltage. As C10 indicates the discharge capacity of the 10H discharge rate, C120 indicates the discharge capacity of 120H discharge rate.
The battery capacity is divided into theoretical capacity, actual capacity and rated capacity. The theoretical capacity is the highest capacity value calculated according to the quality of the active substance; the actual capacity refers to the amount of electricity that the battery can output under certain discharge conditions. Due to the constitutive battery, there is a side reaction occurs in addition to the main reaction of the battery. In addition to other reasons, the active material utilization rate cannot be 100%, so far below theoretical capacity; the rated capacity is also known as the nominal capacity, it is According to the standard promulgated by the national or relevant department, the battery should be discharged at a certain discharge condition (communication battery generally specifies the LOH discharge current discharge to termination voltage) under a certain discharge condition (communication battery is generally specified in the 25 ¡ã C).
Factors affecting the actual capacity are mainly related to the number and utilization rate of battery positive, negative electrode active substances. The active material utilization is mainly affected by the discharge system, the electrode structure, and the manufacturing process. In the process of use, the actual capacity is the discharge rate, the discharge system, the termination voltage, and the temperature.
3, discharge rate
According to the size of the battery discharge current, it is divided into time rate and current.
The discharge ratio refers to the length of the voltage to discharge to the discharge in a certain discharge condition. Commonity time rate and magnification.
Time Rate (hourly) refers to the time required to put the rated capacity of the battery at a certain current value.
According to the IEC standard, the discharge time rate is 20, 10, 5, 3, 1, O.5 hours, respectively, identified by 20 h, respectively.
10H, 5H, 3H, 1H, O.5H, etc. The most common is 20h, 10h hours. Thus, the rated discharge current is obtained using the capacity divided by hours. That is, the capacity is the same and the discharge rate is different, and their nominal discharge current is very far. For example, a battery capacity 10A? H with electric bicycles, the discharge ratio is 2h, write 10A? H2, its rated discharge current is 10A? H / 2H = 5A; and a car started battery capacity is 54A? H? H? H The discharge rate is 20h, writes 54A? H20, its rated discharge current is only 54A? H / 20H = 2.7a! For a point of view, if the two batteries are discharged with 5A and 2.7A, then it should be It can last 2 h and 20 h, respectively, to the set voltage.
The current intensity of the battery is often expressed by the magnification (current ratio), and writing NCH means that the discharge current value is equivalent to a multiple of the battery rated capacity (a? H) value. n is a multiple, C represents the number of times the capacity, and h indicates the time (h) specified by the discharge ratio. Here, the value of H is only a presentation of the related battery belongs to which discharge ratio, so when the battery is specifically described, the magnification is often written into an NC in the form of an NC without writing the mark. The multiple N multiplied by capacity C is equal to current (a). For example, a 20a? H battery is discharged from 0.5C magnification, O.5 ¡Á 20 = 10A. For an angle example: a car starts the battery capacity 54a? H, and the output current is 5.4a, then the discharge ratio NC at this time is (5.4 / 54) c = 0.1c.
4, stop voltage
The termination of the voltage decreases when the battery is discharged to the lowest operating voltage (at least repeated rechargeable charging) when the battery is discharged. In order to prevent the battery, but the polar plate is damaged, the termination voltage of the battery is specified when discharged at different discharge ratios and temperatures in various standards. The termination voltage of the backup power supply series battery 10H and the 3H discharge rate is 1.80 V / monomer, and the 1H discharge rate is terminated. The voltage is 1.75 V / monomer. Due to the characteristics of the lead-acid battery itself, even if the stop voltage of the discharge continues to decrease, the battery does not release too much capacity, but the termination voltage is too low to the battery, especially when the discharge reaches 0V and cannot be charged in time. Great shortens the life of the battery.
For solar energy storage, the termination voltage value is not fixed, which is reduced as the discharge current increases, usually, less than 10 h, the termination voltage is slightly higher; greater than 10h Large current discharge, the termination voltage is at a slightly lower value.
5, cycle life
Battery experiences charge and discharge, called a cycle (one cycle). Under a certain discharge condition, the battery can withstate the number of cycles before the battery is used to a certain capacity specified value, called a cycle life. The backup power supply generally uses a floating service life to measure the life of the battery, such as the floating life of the valve-controlled lead-acid battery is usually more than 10 years, but it can also be measured by battery cycle life. The main factors affecting battery cycle life are the performance and quality of the product, followed by the quality of maintenance work. For backup power supplies, 100% discharge depth discharge, its cycle life is generally 100 ~ 200 times, that is, 100% capacity discharge, battery discharge to stop voltage is 1.8V / monomer, and the battery is discharged to The termination voltage is 1.8V, the discharge capacity is below 80% of the rated capacity, and the battery life is terminated. Factors affecting battery life is integrated factors, not only the internal factors of the plate, such as the composition of the active material, crystalline form (high temperature curing or normal temperature curing), polar plate size, and grid material structure, but also depends on external factors Such as discharge ratio and depth, working conditions (temperature and pressure, etc.) and use maintenance conditions, etc.
6, battery internal resistance
The internal resistance tester of the battery is not a constant, and continuously changes over time during the charge and discharge process, because the generation of the active substance, the concentration and temperature of the electrolyte concentration and temperature are constantly changing. The internal resistance of the lead-acid battery is very small, and it can be ignored when the small current is discharged, but when the high current is discharged, the voltage drop can reach hundreds of millivolts, and must be paid attention to. There are two parts of the battery in the battery. The ohmic resistance is mainly composed of electrode materials, diaphragms, electrolytes, terminals, and the like, and is also related to battery size, structural and assembly factors. The polarized internal resistance is caused by electrochemical polarization and concentration polarization, and is the internal resistance generated by the electrodework during the battery discharge or the charging process. The polarization resistance is related to the activity of the battery manufacturing process, the electrode structure, and the active material, and is also related to factors such as battery operating current and temperature. The battery internal resistance severely affects the battery operating voltage, operating current, and output energy, and thus the internal resistance of the battery is getting better.
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