Detailed explanation of battery charge and discharge tester

The charge and discharge tester is the most commonly used test equipment for power lithium batteries. New batteries need to be matched and screened for consistency; in the process of designing and finalizing the battery pack, multiple tests need to be charged and discharged; the performance of the battery pack needs to be investigated and the working condition test needs to be assisted by a charge and discharge tester; Discharge test health status; some certifications, spot checks and tests required by Party A require charging and discharging.

What are the functions of a general charge and discharge tester?

1) It has the function of constant current and constant voltage charging and discharging, which can realize automatic life cycle, and automatically carry out the test of standard working conditions or artificially set working conditions; cyclic testing can realize the nesting of cycles;

2) It has the function of recording real-time current, voltage, temperature, charge and other related test data and fault data;

3) Different charging and discharging termination conditions can be set, such as total voltage, cell voltage, battery state of charge, etc.;

4) Safety monitoring function, dealing with overcurrent, overvoltage, overtemperature, undervoltage, undercurrent, short circuit, power failure protection, and other fault conditions;

5) According to the test record, draw the time-voltage, time-current, time-stage capacity, time-charge accumulative capacity, time-discharge accumulative capacity, time-total capacity, time-power, time-resistance, time-energy, time - Curves such as the voltage of the single cell, the number of cycles - the capacity at the specified stage (cycle capacity decay curve);

6) Screen display, host computer display, sound and light alarm, screen input, selection, host computer input, selection and other human-computer interaction functions.

The basic working principle of charge and discharge tester

1. Charging process

The battery charge and discharge tester can realize various forms of charging process, constant voltage charging, constant current charging, first constant current and then constant voltage charging, positive pulse charging, positive and negative pulse charging and so on. Different forms of charging process can be completed according to the needs of battery performance.

Constant voltage charging, the charging and discharging equipment is adjusted to the constant voltage source mode. Since the set charging voltage must be a value near the full voltage of the battery, the current value is the largest at the beginning of charging. As the terminal voltage of the battery increases, the voltage difference between the charger and the battery becomes smaller and smaller, and the charging current also decreases gradually. When the charging current decreases to a certain value, the charging ends. Constant voltage charging, the charging current is relatively large in the initial stage, which is not good for the life of the cell.

Constant current charging, the charging and discharging equipment is adjusted to the constant current mode, the current remains unchanged throughout the charging process, and the battery terminal voltage gradually increases over time until it reaches the charging cut-off voltage, and the charging process ends. Constant current charging, if the current setting is relatively small, it will take a long charging time; if the current is relatively large, the polarization of the battery will be more obvious, and the battery voltage will drop significantly after the charging circuit is removed.

The advantages of constant current and then constant voltage, constant current charging and constant voltage charging, first set a relatively large current constant current charging, the purpose is to improve the charging efficiency; when the power reaches a certain value, it is converted into constant voltage charging, and the charging current is gradually decrease. The purpose is to charge the battery more power.

Pulse charging, charging with a large current for a period of time, interrupted by a period of zero current time interval, this time interval can play a depolarizing role in the battery part, reduce the power loss during the charging process, and can charge more power.

Pulse charging can have various forms, variable current pulse charging, variable voltage pulse charging, and positive and negative pulse charging. Taking variable current pulse charging as an example, taking the charging current as the adjustment object, the current remains unchanged for a long time, and is interrupted for a short period of time after this period, and then a continuous constant current charging occurs, and so on. On a large trend, the current follows a gradually decreasing law. Variable voltage pulse charging is similar to variable current pulse charging, except that the object of adjustment is replaced by voltage. During the charging process, the current decreases according to the law, while the voltage increases according to the law. Positive and negative pulse charging replaces the zero current time of the interval with negative current, which is said to be for better depolarization.

2. Discharge working process

The battery charge and discharge tester tests the discharge performance of the battery, mainly for different scenarios such as life test, working condition simulation test, capacity test, consistency screening, and other battery parameter tests and safety tests. Different test purposes determine the changing laws of current and voltage during the discharge process. The current and voltage requirements can be input in the host computer, and the tester will adjust the power supply to output as needed according to the requirements of the control system.

If you want to know more about the charge and discharge tester, please contact E-Nanny Electric factory, a manufacturer specializing in the production of Battery Charge and Discharge Tester, Battery Discharge Tester, Battery Discharge Test System and other battery test instruments, worthy of your trust.