Common technical parameters of lithium battery UPS. When selecting lithium battery UPS, when you apply the lithium battery UPS according to the requirements or select the lithium battery UPS according to the recommendations of the lithium battery manufacturer, for example, the machine room selects the rack UPS. Or a tower UPS or the like. After selecting the type of lithium battery UPS? Then you need more specific parameters.
Let's talk about the parameters that people usually look at in the lithium battery UPS. I think many people have a lot of understanding about these parameters, so they have some understanding of the meaning of the general representative, but they still don’t know much about the definition. Let Cuneng Electric Xiaobian collect its specific meanings for everyone to see, the following definitions are mainly collected in Baidu Encyclopedia.
battery capacity
Battery capacity is one of the important performance indicators to measure battery performance. It indicates the amount of electricity discharged by the battery under certain conditions (discharge rate, temperature, termination voltage, etc.) (discharge test can be performed with JS-150D), that is, the capacity of the battery, usually Ampere·hours (abbreviated as A·H, 1A·h=3600C).
The battery capacity is divided into actual capacity according to different conditions, theoretical capacity and rated capacity. The calculation formula of battery capacity C is C=∫t0It1dt (integration of current I during t0 to t1), and the battery is divided into positive and negative poles.
Q
The nominal voltage is a term of physics and refers to the voltage value corresponding to the nominal operating current of the regulated thermistor at +25 ° C. The most commonly used voltage regulator thermistor has a nominal voltage of 2 Volt, other 3 volts, 4 volts, 5 volts, 6 volts, etc. The nominal voltage is also an appropriate voltage approximation, also known as the rated voltage, that can be used to identify the type of battery.
The battery nominal voltage is an appropriate voltage approximation, or voltage rating, that identifies or identifies a battery. It can be used to identify the type of battery. For example, the open circuit voltage of a lead-acid battery is close to 2.1V, and the nominal voltage is 2.0V. The nominal voltage is 1.5V, nickel-cadmium battery, nickel-hydrogen battery nominal voltage is 1.2V, lithium-ion battery nominal voltage is 3.7V.
In fact, the nominal voltage does not refer to the battery voltage. The actual voltage of the battery varies according to the actual capacity of the battery. The nominal voltage of the same battery may be different in different scenarios or regions. The battery is actually not. Changing.
Battery internal resistance
The internal resistance of the battery refers to the resistance that the current flows through the inside of the battery during operation. It includes the internal resistance of the ohmic and the internal resistance of the polarization. The internal resistance of the polarization includes the internal resistance of the electrochemical polarization and the concentration of the polarization. Resistance.
For lithium-ion batteries, the internal resistance of the battery is divided into ohmic internal resistance and polarization internal resistance. The ohmic internal resistance is composed of electrode material, electrolyte, diaphragm resistance and contact resistance of various parts. Polarized internal resistance refers to electrochemical Resistance caused by polarization during the reaction, including resistance caused by electrochemical polarization and concentration polarization.
The actual internal resistance of a lithium-ion battery refers to the resistance that the current is flowing through the inside of the battery during operation. The internal resistance of the battery is large, and a large amount of Joule heat is generated during the normal use of the battery (according to the formula: E=I^ 2RT) causes the battery temperature to rise, resulting in a lower battery discharge operating voltage, shorter discharge time, and serious impact on battery performance and life.
The exact calculation of the internal resistance of the battery is quite complicated, and it will change constantly during the use of the battery. According to experience, the larger the volume of the lithium-ion battery, the smaller the internal resistance, and vice versa.
Self-discharge rate
The self-discharge rate, also known as the charge retention capacity, refers to the ability of the battery to maintain the power stored under certain conditions under open conditions. It is mainly affected by factors such as battery manufacturing process, materials, storage conditions, etc. Important parameters.
The self-discharge size, ie, the self-discharge rate, is related to the solubility of the positive electrode material in the electrolyte and its instability after heating (easy self-decomposition). The self-discharge of the rechargeable battery is much higher than that of the primary battery. And the battery type is different, the battery The monthly self-discharge rate is also different. Generally it varies at 10-35%. The storage process is accompanied by self-discharge, which is the increase of the battery internal resistance, which will cause the battery load force to decrease, and in the case of a large discharge current. The change in energy loss is very obvious.
The value of one of these parameters alone is not enough to judge the performance of the lithium battery UPS. It is also necessary to refer to other technical parameters to comprehensively judge the performance of the selected lithium battery UPS.
