How to control the accuracy and safety of lithium batteries from the source?

How to control the accuracy and safety of lithium batteries from the source? In the processing of lithium batteries, the evaluation of battery capacity and function is a very important link. From low capacity (10), it is mainly used in mobile phones, cameras and hybrid vehicles, media capacity (10a-30a) is used for computers, electric motorcycles and electric vehicles, and high-capacity lithium batteries are used for electric vehicles (30-120a). With one exception, they are all tested before leaving the factory. According to Li Qiang, a system application engineer in the Asia Pacific Precision Instrument Division of ADI, the most common practice in the industry is to use linear test equipment to test small-capacity batteries. Although the power is low and the accuracy is not high, it can still bear it. However, if the same test equipment is used to test a large-capacity battery, a large amount of power will be consumed during the charging phase, resulting in low power consumption, and serious thermal problems regarding equipment hardware planning. Therefore, ADI proposes AD8450/1 precision analog front-end and controller and ADP1972 Buck/improved PWM controller in the specially designed low, medium and high capacity lithium battery RongHuaCheng equipment, abandoning the traditional battery energy discharge impedance load linear structure, and then use The PWM controller powers the current and guides them back to the grid or other batteries for high efficiency and environmental protection purposes. The test data shows that in the charging mode, when the voltage is 3.5v, the power value of 20A is 88%, and the power value of 10A is 90%. In the discharge mode, when the voltage is 3V, the power value of 20A is 89%, and the power value of 10A is 92%. In addition to electricity, lithium battery companies are more concerned about cost and reliability. Li Qiang said that there are also lithium battery testing methods with discrete component combinations on the market, and more than 10 devices may be used. ADI only uses two chips, ad845/1 and ADP1972, these two chips are highly integrated, which greatly reduces the planning standard. In addition, by increasing the switching frequency to 300KHz, multi-channel high-precision DACs and ADCs have lower co-costs, and phase-shift synchronization between channels reduces input filtering and reduces the total system cost. In addition, ADI also provides users with plans and all reference plans to minimize development costs and planning difficulties, and shorten the development cycle. ADI processing method system structure diagram How to share DAC and ADC across multiple channels? The above figure contains two functions: one is to charge the battery, the other is to discharge the battery, which is selected by the ad845/1 and ADP1972 signals. Each function has two modes: constant current (CC) mode and constant voltage (CV) mode. Two DAC channels control the CC and CV set points. The CC setting value determines the size of the loop current in the charge and discharge CC mode. The battery potential of the CV set point selection loop from CC to CV is the same with respect to charging and discharging functions. The precision analog front end and controller ad845/1 use the internal differential amplifier PGDA to measure the battery voltage, and the internal external amplifier PGIA and external shunt resistor (RS) to measure the battery current. Then through the internal fault amplifier and external compensation network (used to verify that the loop function is CC or CV) the current and voltage are compared with the DAC set value. After the module is completed, the output of the faulty amplifier enters the PWM controller ADP1972 to determine the duty cycle of the MOSFET power level. In the end, inductance and capacitance form a loop without any defects. Since ADP1972 is a PWM controller for step-down and step-up, the instructions in this section apply to the charge and discharge functions at the same time. In this case, the ADC reads the loop voltage and current, but it is not part of the control loop. The scan rate has nothing to do with the function of the control loop, so the ADC can measure the current and voltage of multiple channels in a multi-channel system. The same is true for DACs, so you can use low-cost DACs to set up multiple channels. In addition, a single processor can interact with multiple channels as long as it controls the CV and CC set points, how to operate and what to do. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous post: Comparison of lithium battery packs and lead-carbon battery packs