When testing battery capacity, the battery divider cabinet mainly ensures testing accuracy through the following methods:
High precision measuring instruments:
1. Use precision sensors: for example, use high-precision current sensors and voltage sensors. The measurement accuracy of the current sensor may reach ± 0.05% FS (full range)+0.05% RD (reading), which can accurately measure the current during the charging and discharging process; The measurement accuracy of voltage sensors for battery voltage can be controlled within a very small range, such as ± 0.05V, to ensure the accuracy of voltage data.
2. Calibration of measuring instruments: Before the equipment leaves the factory, sensors and other measuring instruments will be calibrated. Users also need to regularly (such as annually) use a 0.1 level digital multimeter and digital ammeter to recalibrate the current and battery sampling voltage of each channel to eliminate errors in the measuring instrument itself and ensure measurement accuracy.
Stable charge and discharge control:
1. Stability of constant current and constant voltage sources: Equipped with stable performance constant current and constant voltage sources, ensuring stable output of current and voltage during the charging process. The constant current source has a normal constant current path during charging and discharging, precise current regulation, and accurate alarm indication; A constant voltage source can stably maintain voltage output when the battery is charged to the set voltage, avoiding the impact of voltage fluctuations on capacity testing.
2. Accurate setting of charging and discharging parameters: Based on the characteristics and process requirements of different types of batteries, accurately set parameters such as charging current, discharging current, charging voltage, and discharge termination voltage. For example, for lithium-ion batteries, the setting of charging current and voltage needs to comply with their specific charging curve to ensure that the battery can be charged and discharged under safe and appropriate conditions, thereby accurately measuring capacity.
Reliable sampling and data recording:
1. High speed sampling frequency: The capacity divider cabinet has a high sampling speed, such as a full cabinet inspection time of ≤ 1s, which can quickly and real-time collect voltage, current and other data of the battery during the charging and discharging process, ensuring that no key change points are missed and fully recording the battery's charging and discharging characteristics.
2. Multi channel independent sampling: Each battery channel has a completely independent sampling circuit, which can independently and accurately sample the voltage, current, and other information of each battery, avoiding mutual interference between channels and ensuring data reliability. Even if large-scale battery packs are tested simultaneously, the accuracy of data for each battery can be ensured.
3. Strict data recording conditions: Save all step curves of each battery, including voltage time, current time, capacity time, and charge time curves. The conditions for saving curve points include voltage difference (≥ 5mV), current difference (≥ 5mA), time difference (≥ 1min), etc. Users can freely choose curve sampling conditions to analyze the performance and capacity change process of the battery in detail.
Optimized testing environment and fixtures:
1. Stable environmental conditions: The capacity divider usually operates in a constant temperature and humidity environment, reducing the impact of environmental temperature and humidity on battery performance and measurement results. For example, temperature changes may cause changes in the internal chemical reaction rate of the battery, thereby affecting the charging and discharging performance and capacity measurement of the battery. Stable environmental conditions can reduce this impact.
2. Good battery clamp: Regularly clean the battery clamp to ensure reliable contact between the battery and the clamp, and prevent measurement errors caused by poor contact. If the battery crawls alkali, it should be cleaned immediately to prevent alkali from corroding the battery fixture, affecting the connection and measurement accuracy of the battery.
Advanced software algorithms and system design:
1. Software algorithm correction: Advanced software algorithms are used to process and analyze the collected data, such as filtering, denoising, interpolation, etc., to remove abnormal data and interference signals, and improve the accuracy and reliability of the data. Algorithms can also be used to fit and analyze the charging and discharging curves of batteries, more accurately determining their capacity and performance.
