Performance and safety are critical factors in electric vehicle (EV) battery manufacturing. The two are linked because a battery that fails to deliver the required level of performance is a liability and can create safety issues for the field user. To ensure safety and reliability, battery manufacturers require high-precision measurement and inspection systems. Precision measurement technologies help operators quickly detect flaws and inconsistencies in battery design at each stage of production.
To fully understand and appreciate the role of precision-based measurement systems in EV battery manufacturing, this article discusses why accurate measurements are essential, the precision-based tools used to do so, and the challenges faced in EV battery manufacturing. It also discusses ways to solve identified problems with advanced measurement techniques that guarantee precision.
Figure 1. Precision measurement results in precision manufacturing, which in turn guarantees that EVs meet the strict, rigorous standards of the automotive industry and perform efficiently and reliably.
Taking accurate measurements
EVs and the batteries driving their performance are not new inventions. The first electric car with a rechargeable battery surfaced in the late 1800s. Over the years, the design of EV batteries has improved significantly. This makes for improved capacity and reliability.
However, now manufacturers must find new ways to enhance the performance of electric batteries. New consumer requirements are demanding battery systems that can power longer journeys. Fast charging, which conveniently means less waiting at charging stations, is also gaining traction.
Precision measurement is a critical part of meeting the demands of advancing EV batteries. It’s a crucial step for building battery cells, modules, and packs that can power extended drives, charge fast, and effectively incorporate efficient production materials without sacrificing reliability.
High-precision measurement devices are a form of advanced measurement technology that delivers high-level accuracy measurements even in fast-paced EV battery plants. For example, certain precision measurement devices can measure how well-seated battery IC chips are on a circuit board and the orientation of components. Using precision measurement tools can also help expose defects in inlet weld seams and improve the dimensional accuracy of inner and outer parts.
Tools and techniques
Two essential precision-based measurement systems for EV battery manufacturing, include:
- Vision systems: Machine vision systems use high-speed cameras, optics, lighting, and measurement algorithms to capture and analyze image data. Vision products can be used in EV battery manufacturing plants to determine the dimensions of accuracies of battery components and inspect for defective and missing parts. Aside from high precision, they also offer speed and performance, which is highly advantageous for streamlining production and ensuring efficiency.
- Laser sensors: This measurement/inspection system works by projecting a light beam on a target surface and measuring how long the light takes before reflecting back. The “round trip” time is calculated to determine the distance. Through distance, laser sensors create the 3D profile of the target. The target can be a battery’s internal components or outer parts. Laser-based sensors are deployed as advanced measurement systems for inline measurement and inspection tasks in EV battery production lines.
Challenges
Challenges during high-precision battery measurement, such as dimensional inaccuracies, defects, and deviation from quality standards, largely depend on the battery type. Lithium-ion batteries are the most common type of battery used in EV systems and include prismatic and pouch cells.
Figure 2. There are three types of lithium-based battery cells for EVs: cylindrical, prismatic, and pouch. Each type of battery has a specific chemical composition, size, capacity, and lifespan that make them more or less desirable for EVs.
A typical challenge for EV prismatic cells occurs during the welding process, as these battery systems require extensive welding at the cell sheet level. Inspecting the weld seams around the housing panels can be particularly difficult due to the tightly stacked configuration of prismatic cells. Subtle defects — such as cold joints, small holes, or fine cracks — are often hard to detect but can lead to serious issues.
Therefore, any measurement or inspection device used for prismatic batteries must be capable of identifying even the most minor defects. Failing to do so can result in welding seam problems, potentially causing short circuits or battery failure under high-performance conditions.
One solution is inline 3D laser sensors, which provide highly accurate measurements and inspections of dimensions, surface profiles, and positions of components — even in tightly packed environments.
Pouch-type EV batteries are metallic and flexible, so they create many wrinkles and specular glare that make measuring and detecting critical flaws challenging for the system being used. This is a serious problem when a vision system classifies allowable cosmetic blemishes on a pouch cell surface as critical flaws. This false positive can increase scrap rates and the cost of production.
This challenge can be completed with the help of an AI-powered vision system. This measurement/inspection system can analyze thousands of labeled images to learn what is acceptable and what is not, ensuring inspection and measurement results are accurate.
Pouch-type EV batteries, with their metallic and flexible design, tend to develop wrinkles and specular glare. This makes it challenging for vision systems to accurately detect critical flaws. A significant issue arises when the system mistakenly classifies minor cosmetic blemishes as severe defects, leading to false positives that increase scrap rates and production costs.
Figure 3. Electric vehicle vision systems can detect misalignment and other anomalies that occur during the assembly process, such as improper welding spots and inconsistent spacing between battery cells.
An AI-powered vision system can overcome this challenge by analyzing thousands of labeled images to differentiate between acceptable imperfections and critical flaws, ensuring precise inspection and measurement results while reducing unnecessary waste.
Summary
High-precision measurement equipment and techniques are critical for ensuring accurate results, particularly in producing rechargeable batteries for electric vehicles (EVs). These precise measurement systems enable manufacturers to create batteries that support long-range driving, fast charging, and sustained power retention under demanding conditions. By getting these measurements right, manufacturers can produce vehicles that meet the performance expectations of end users and deliver reliable, high-quality EVs.
When EV battery performance meets expectations, everyone benefits. Battery manufacturers meet quality standards and secure more orders. EV makers can produce vehicles that satisfy consumer demands and uphold their brand reputation, and drivers enjoy maximum value from their investment with reliable, high-performing vehicles.
Filed Under: Batteries, FAQs