How to distinguish between A-grade, B-grade, and C-grade 18650 battery cells?
What is an A-grade lithium battery?
Grade-A is the highest quality battery cell. Its battery materials, technology, energy storage, stable charging and discharging, specifications, constant temperature standards, etc. are all high-quality standards in the industry. A-class battery cells are generally ordered directly from the battery cell manufacturer by the factory using the battery cells. Cell manufacturers arrange production based on the factory's production and technical capabilities. After a series of battery cell production processes, the battery cells are finally produced and delivered to customers. Before placing an order, battery cell manufacturers usually inform us of parameters such as battery capacity, thickness, length, and width.
Then,
batteries manufactured entirely according to the order standards are called A-grade cells. A-class battery cells generally come with a QR code, which contains detailed information about the battery specifications. The various indicators of the battery are also safe and comply with the specifications. For example, the capacity is generally slightly higher, such as EVE's 100Ah lithium iron phosphate battery cell, which has an actual capacity of 102Ah. However, due to the booming development of the new energy vehicle market, electric vehicle batteries are in short supply. Meanwhile, A-class battery cells are generally preferred for use in new energy vehicles, making it difficult to directly purchase A-class battery cells produced by large factories in the market.
What is a B-class battery cell?
Any product produced by a factory will have a defect rate. So this defect rate determines the vitality of a factory. In the lithium battery industry, the gap between first tier lithium battery factories and third tier lithium battery factories is not significant simply in terms of technology, ingredients, and other aspects.
However, considering the production process, there is a significant difference in the defect rate among manufacturers. First tier manufacturers can reach around 2%, while second - and third tier manufacturers may reach 5% -10%. It is precisely because of this defect rate that B-class batteries are produced.
B-class battery cells only have slightly different capacities, or their length, width, and thickness do not meet the order requirements, but their performance is not discounted and their price is cheaper than A-class battery cells. In addition, A-class batteries are generally stored in warehouses, and if they are not shipped for 3-6 months, they are also known as B-class batteries. Of course, this is just a folk belief.
What is a C-class battery cell?
C-grade battery cells are below average in all aspects and below the standards of A-grade and B-grade battery cells. C-grade batteries differ significantly from A-grade batteries in terms of energy storage, stable charging and discharging efficiency, battery materials, technology, and repeated charging and discharging. If a B-class battery cell is stored in the warehouse for more than 8 months without being shipped, it can be called a C-class battery cell. Due to the long storage time of C-grade battery cells, their performance begins to decline as they age due to self discharge, dust, and water vapor. Battery expansion sometimes occurs during charging, and sometimes during leakage and short circuits.
C-grade battery cells generally have only about 50% -60% of the performance of A-class battery cells of the same type, and the best can reach 70%. The safety of C-grade battery cells is relatively low. In addition, C-class batteries are not durable and their performance will be greatly reduced after several cycles of charging. C-grade battery cells generally do not meet the requirements for capacity, internal resistance, and self discharge rate. Some automotive power batteries may also enter the market after retirement, so purchasing battery cells should be cautious.
How to distinguish different levels of batteries?
The simplest way to distinguish between A-class and B-class batteries is to have the original manufacturer's test report for A-class batteries. The data should include the internal resistance, voltage, capacity, and product code of each battery cell (usually the same as the information on the QR code). If there is no such information, 99% of them may be B-class cells. Usually, some A-class battery cells are recycled and reused from electric vehicles, and these batteries are usually considered B-class battery cells.
