How to Detect Bad 18650 Cells Automatically?

To detect bad 18650 cells is important in high-volume lithium battery production and pack assembly.
Singly failing 18650 cells can cause both capacity imbalance and overheating, shorten the life of a whole pack or even represent a risk to safety on a much larger scale. Manually inspecting 18650s is not feasible when thousands need processing every day. For this reason automatic 18650 cell detection and sorting are used in battery factories, energy storage projects, and recycling lines.
Focus for automatic detection is on identifying cells which fail electrical, physical, and consistency tests prior to inclusion in a battery pack.
Common Types of Bad 18650 Cells
Typically bad cells can be low in capacity, or unstable, and may show abnormally high IR. Alternatively they may show voltage deviation, self-discharge issues, or mechanical defects such as dents or swelling, or fail to make proper contact with terminals. Cells from the same batch could produce a wildly different performance if not properly graded.
These hidden flaws cannot be detected using visual examination meaning automated test stands are required.
How are Automatic 18650 Detection Systems Working?
An automatic 18650 battery sorting machine will be measuring several parameters simultaneously. The most important are the open-circuit voltage, internal resistance (IR) and capacity see below and sometimes AC impedance or temperature behaviour. Usually voltage is the first test as first stepping stone.Cells that are too high or too low will be flagged, and the IR testing is as important as it tends to reflect internal wear/damage or a poor electrode structure. Capacity testing then tells us whether a cell is capable of its rated energy, given controlled charge and discharge conditions.
Most modern lithium battery sorting machines do all these tests and ultimately draw conclusions on what the sort criteria will be for the cell taking into account the test results as well as previous reporting.
How Do Automatic 18650 Cell Sorting Machines Work?
An automatic 18650 cell sorting system integrates the feeding, the testing and data assimilation, and the physical sorting in a single operation. Modules located on each side for instance of a central conveyor or battery feeder arrange cells into place so that probes can touch down exactly where it is desirable.
IR tester, voltage tester and capacity testing modules can record specifics of each cell in milliseconds. All of the collated data is based on preset standard rules to declare which cells belong in which grades of sort, A-grade, B-grade and reject. A rejected cell will simply bolt away from the flow and be ejected without touching the hands of an operator.
On higher speed lines its common to require usable pins to replace tipped devices. Many systems use pogo pin contact structures that usually improve contact stability, especially in high speed sorting.
What Is Automatic Detection Advantages Over Manual Methods?
-Far greater in terms of the volume of cells that can be processed. An automatic cell sorting machine for 18650 cells can easily handle thousands each hour, while manual methods will struggle with numbers in the hundreds. Perhaps even more important than the sheer volume of cells passed through however, is the repeatability and traceability the detection data furnishes the manufacturer for his own quality control and also for after-sale analysis of causes for pack performance drops, warranty claims, or false alarms and pack scrambles.
By separating out the bad cell before pack assembly, the manufacturer saves on post production rework costs, warranty claim, or even false safety alarms through pack fires. This is crucial in products such as EVs and even a fault in a solar energy storage system, battery-charging power tools can mean nuisance or fatal harm.
Automatic Cell Detection Example Scenarios
Automatic 18650 cell detection is destined for wide application in the production of lithium battery packs, grading centers for actual batteries, it’s even a key sequence used in also second-life battery sorting projects or recycling projects in light of the often mixed bag of cell conditions in such.
To sum it up, when planning an automatic series such as of 18650s, the designer and manufacturer can afford to keep faith that if all goes well, all will in conventionally used terms. In other words, cells with good data will go on to make the grade, whilst did not make it today will go away.
Choosing The Right Detection Equipment
One of the most important consideration when making a choice about the automatic 18650 battery sorting machine will be testing accuracy of results:
Next in line will most probably be number of channels in semi-auto or fully automatic systems and the sorting technology speed matched to specific sorted grade and product channel speed. A ballpark figure average inspection channel counts may be in excess of 1280 channels on production machines. Other things to consider will be whether modules such as the tester can be plugged in at some future date to increase numbers to to, for example 2240.
Lastly, customs like lithium battery sorting machine manufacturers keep in mind, and since it begun, it has always carried the promise to also test (and sort in some ranges) 21700 cells or 32700 cells or greater formats. Naturally the machines that are supplied state of the art treatment and mechanisms wait out for wanted and old desirable users and consumers.
Final Thoughts
Detecting bad 18650 cells automatically is an essential part of a standard modern battery business. Today, with accurate voltage, IR and capacity testing, combined in an automatic sorting cells machine, the manufacturer can actually start to breathe easier knowing the return on packs should be significantly of greater safety for all involved and vested in the pack, greater performance and more years in battery life.