Lithium-ion battery pack capacity grading: Simply put, it's capacity sorting and performance screening. Battery capacity grading involves charging and discharging the batteries, and determining the capacity of the lithium-ion battery pack by testing the discharge capacity at full charge. During capacity grading, a computer manages the data from each test point, thereby breaking down the data into the battery capacity and internal resistance, and determining the battery's quality level. This process is called capacity grading.
The processed lithium battery cells cannot be sold immediately. They should be stored in the warehouse for at least 15 days. During this period, some inherent defects will become apparent, such as excessive self-discharge. After receiving an order, the battery cells that have reached their storage period in the warehouse will be taken out for testing and capacity assessment again. That is, they will be charged and discharged again to eliminate those that do not meet the capacity requirements or have quality problems. Then, they will be delivered to the sales department with about 50% of their capacity remaining, and finally to the mobile phone battery assembly plant.
The battery cells, soon to be packaged as lithium-ion batteries, undergo another formation process for capacity assessment. This process helps identify and remove any substandard cells, which are then returned to the cell manufacturer. Mechanical testing during lithium-ion battery testing confirms that the cells have undergone charging and discharging and are indeed charged. Therefore, it's normal for the battery to have two bars of charge upon arrival.
The lithium-ion battery pack capacity assessment allows for single-point start-up and single-point stop of each channel, resulting in a fast response time. Each channel has an independent constant current source and constant voltage source, with real-time current and voltage sampling. The switching between constant current and constant voltage is truly seamless. It can also be used for cycle life testing.
