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Enhancing EV Battery Performance with Advanced Inspection Solutions
Discover how Tensor ID innovates EV battery inspections, utilizing Teledyne DALSA cameras and AI, ensuring optimal performance with precision checks.
3D rendering EV car with a pack of battery cells modules on a platform in the laboratory.PhonlamaiPhoto/ iStock / Getty Images Plus
When inspecting batteries that power EVs, the inspection system must address multiple challenges, including a thorough inspection of each battery cell for issues like rust or dents, because when one cell is damaged, it diminishes the life of the whole battery pack.
As explained in a previous article titled “Why Emerging Trends in Battery Packing Matter,” the batteries in EVs are made up of hundreds, if not thousands, of individual cells, usually grouped into modules. Up to several dozen modules can reside within a battery pack, which is the complete EV battery. These individual battery cells resemble well-known AA batteries and are encased in a clamshell-type plastic enclosure to make up the module.
EV batteries are worlds apart from the heavy lead-acid batteries in conventional combustion engine cars. They are much closer to the ones in your mobile phone or laptop, yet more reliable and with a vastly increased life span. There’s no lithium metal in the batteries, only ions – atoms or molecules with an electric charge.
As a specific example, Tesla reports that its flagship electric sedan, the Model S, typically comes with two battery pack options: a standard-range and a long-range version. The standard-range Model S utilizes a battery pack of approximately 4,416 individual battery cells, while the long-range version contains around 8,256 cells. On the smaller end, the Chevy Bolt has only 288 battery cells.
The biggest battery packs are massive, measuring a few meters long and weighing several hundred kilos; this is why most are placed under the floor inside a car’s chassis in what’s sometimes called a skateboard configuration. The expected electric car battery life is at least a decade, and many EVs come with warranties for eight years or 100,000 miles.
According to JD Power, the battery costs are the most expensive element of electric vehicles. A battery might cost between $4,000 and $20,000, depending on the brand and model of your vehicle. Although many EVs will never need a battery replacement, this is a significant expense if the vehicle is out of warranty. Brand reputation is another reason EV manufacturers want to ensure the highest quality possible for their batteries, which is tied to quality inspection.
What happens during battery inspection?
The battery cells come in boxes from the supplier, and a robot is deployed to remove one at a time for inspection. Each battery cell must be inspected before they are put into the clamshell module, which will become part of the battery pack. Battery manufacturers are concerned about reading the barcode, identifying rust and dents, and determining polarity.
Barcodes: Each battery cell is identified by a 2D barcode. The vision system scans the barcode and is spun around so that the vision system can scan it. The lot number will have information about the date the battery was created. Batteries that are too old are removed.
Rust: From there, the cameras look for rust on the battery's body. A battery cell could be shiny or dull; it doesn’t matter how the battery looks. However, if rust is present, it could penetrate the layers of the battery and affect battery life.
Dents: The system looks for dents on the side of the battery. Micro-dents won’t have an effect, but deeper dents can affect the dielectric material and reduce battery life. The battery cell comprises layers, almost like a cinnamon roll. If a dent on the side of it meets metal on the inside, that battery cell life may be depleted by more than 50%. Although the complete battery pack will still work if one or two of the cells are dead, it will affect the overall life of the battery pack.
Polarity: When the battery cells arrive from the supplier, they are not positioned or oriented in terms of polarity; some could be positive, and some could be negative. Part of the inspection process is validating the polarity and correctly aligning all the batteries in terms of positive or negative polarity.
With these elements in mind, Tensor ID created a machine vision system to inspect the battery cells and determine these issues.
Tensor ID’s system set up
AI improves inspection performance and is used to identify rust. Four high-resolution cameras from Teledyne DALSA are used to inspect the battery module. (Image courtesy of Tensor ID)
Tensor ID developed a vision inspection system using Teledyne DALSA area scan cameras to inspect each battery cell — both at the individual level and as they're entirely assembled just before they put the clamshell casing over it.
To inspect the stack of batteries accurately, Tensor ID uses four Teledyne DALSA Genie Nano cameras positioned to capture an image “stitched” together from an entire three-foot-wide stack. The cameras can detect defects, including rust and dents. Tensor ID has used both traditional machine vision cameras and the Teledyne DALSA Z-Trak2, a 3D laser profiler, to measure depth.
Traditionally, it has been challenging to recognize rust or dents because of the shiny surface of the battery cells, and the reflections often cause problems. Tensor ID came up with a unique lighting technique, and using the Teledyne DALSA cameras and Sherlock software, it has overcome the issue of shiny surfaces.
Regarding the inspection of rust, an AI-based software platform is used to classify the images. Sometimes, the battery cells have fingerprints or a speck of debris or dirt — these aren’t a problem regarding functionality, but rust is. Training the AI model with Teledyne DALSA’s Astrocyte AI training tool enables the system to recognize the difference between rust and other anomalies; it can identify and remove any battery cells with rust on them.
The race for EV battery innovation and quality
In the fast-paced world of technology, batteries have become the unsung heroes powering our devices and driving innovation. From Samsung to LG Chem to Panasonic, a fierce battle is raging to secure battery patents and supply batteries for this emerging segment of the automotive market.
Ensuring the quality and efficiency of batteries is a critical consideration for every battery supplier and electric vehicle (EV) manufacturer. Overlooking even a single dent or rust spot among thousands of battery cells in an EV can significantly affect long-term performance, leading to potential replacement costs and impacting customer satisfaction. Therefore, adopting effective battery inspection solutions is imperative to guarantee the optimal functionality of EV battery packs.
About Tensor ID
Tensor ID, headquartered in Oceanside, California, offers comprehensive machine vision solutions for addressing battery inspection challenges. Their expertise extends across various technologies, including traditional machine vision cameras, thermal imaging, X-ray cameras, and advanced AI and deep learning tools. Multiple sectors, including battery manufacturers and leading electric vehicle (EV) companies, rely on companies such as Tensor ID to navigate the challenges associated with battery inspections.
About the Author(s)
Chief Technology Officer , Tensor ID
Regional Sales Manager , Teledyne DALSA
Dave Richardson is a Regional Sales Manager for Teledyne DALSA, a provider of high-performance machine vision solutions. Dave works closely with customers to help them choose the best OEM components – such as machine vision cameras and software – for the inspection systems they build. Dave can be reached at [email protected].
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