Lithium-ion battery alignment detection technology
main content
Alignment is one of the core quality indicators in lithium battery manufacturing, directly determining the spatial positional relationship of key components such as positive and negative electrode sheets and separators inside the battery cell. In high-vibration and high-power scenarios such as lithium-ion start-stop batteries for motorcycles, if the alignment error of the electrode sheets exceeds 50μm, it can lead to abnormal local current density and trigger the risk of thermal runaway. This article conducts an analysis from the aspects of technical mechanism, detection methods, the particularity of motorcycle applications and innovation directions.
1. The precise matching requirements of the battery cell structure
The interior of a lithium battery is composed of alternating layers of positive electrode sheets, negative electrode sheets and separators. Under ideal conditions, the active regions of the positive and negative electrodes should completely overlap, and the positions of the tabs should be precisely aligned. Motorcycle batteries need to withstand random vibrations of 10200Hz (with an acceleration of 1020g). When the positive and negative electrodes are misaligned by more than 100μm, the tabs are prone to move and rub against the separator during charging and discharging, causing a micro-short circuit.
Capacity loss: The misaligned areas of the active substances on the positive and negative electrodes cannot participate in the reaction. For every 1mm of misalignment, the effective contact area is lost by approximately 5%.
Safety risk: The probability of burrs or foreign objects at the edge of the electrode sheet penetrating the separator increases exponentially with the amount of misalignment. When the misalignment amount is ≥200μm, the short-circuit incidence rate in the needle-puncture test increases by three times.
2. Cumulative effect of multi-process errors
The alignment deviation mainly stems from the process fluctuations in the three major procedures of die-cutting, winding and laminating:
Die-cutting accuracy: An error of ±0.1mm in the TAB spacing will result in a cumulative misalignment of 7mm after 50 turns of winding.
Winding tension: When the tension gradient control deviation is greater than ±5%, the electrode sheet will shift laterally under the action of centrifugal force.
Stacking positioning: The repeat positioning accuracy of the robotic arm being less than ±0.05mm is the basis for ensuring alignment at the 0.1mm level.
Ii. Evolution of Motorcycle Battery Alignment Detection Technology
1. Offline detection technology
X-ray imaging detection
Tomographic images were generated using a 225kV microfocus X-ray source (with a resolution of 2μm), and the offset of the positive and negative electrode edges was identified through the gray-scale contrast. The Tianjin Sanying Precision nanoVoxel4000 system can detect 10μ m-level electrode sheet misalignment and, in combination with AI algorithms, achieve defect identification with a porosity of ≤2%.
Laser displacement sensing
The position deviation is measured in real time by scanning the edge of the electrode sheet with a linear array laser. The Zeiss SmartRunner Explorer 3D sensor has a measurement accuracy of ±5μm in the Z-axis direction and is suitable for the dynamic monitoring of wound battery cells.
2. Breakthrough in online detection
CCD visual positioning
A 5μm linear array CCD is adopted in combination with a six-axis mechanical arm to achieve a positioning accuracy of ±0.03mm for the TAB position. The Dataifeng XRAY equipment integrates deep learning algorithms and can complete the full inspection of electrode plate alignment at a production capacity of 4,000 PCS/h.
Laser vision fusion
The Guangdong Dongbo Intelligent patent equipment (CN222753808U) adopts dual-station alternating detection, combining X-ray imaging with geometric shape search algorithms, which increases the detection efficiency by 30%.
Iii. Special Testing Requirements for Motorcycle Batteries
1. Anti-vibration design adaptation
Dynamic compensation technology: In the winding process, servo closed-loop tension control (accuracy ±0.5N) is adopted to counteract the displacement of the electrode sheet caused by high-frequency vibration. The Tianfeng brand motorcycle battery adopts a pre-pressed corrugated nickel strip design, which ensures that the anti-peel strength of the tabs under vibration conditions is ≥6kgf.
Flexible electrode structure: The silicon-based negative electrode adopts a wavy TAB design, allowing ±0.2mm dynamic expansion and contraction, and is combined with ultrasonic welding to enhance interface stability.
2. Low-temperature performance optimization
Material matching detection: When using EA/PC mixed solvent electrolyte, it is necessary to ensure that the consistency of the electrode sheet expansion rate is ≤0.8mm/1000 cycles. The alignment detection needs to verify the difference in electrode sheet shrinkage at 30℃.
Thermal stress simulation: Analyze the deformation law of the electrode sheet under alternating working conditions from 40℃ to 85℃ through CT scanning, and establish a thermal expansion coefficient compensation model.
1. Intelligent detection system
Digital twin model: The Tianjin Lishen Patent CN222353127U tooling integrates X-ray and mechanical simulation, which can predict the displacement trend of the electrode sheet after 2000 cycles and achieve preventive process adjustment.
Multimodal data fusion: Zeiss INSPECT XRay system combined with geometric shape search (ShapeTrax) and deep learning improves the accuracy of composite defects such as folds and fractures to 99.8%.
2. Composite detection technology
Microwave-laser combination: By using microwave to detect the dielectric constant distribution of the electrode sheet and synchronously measuring the topography features with laser, non-contact full-dimensional detection is achieved.
Ultrasonic-optical synergy: 20MHz ultrasonic waves detect the interlayer bonding state of electrode sheets and fuse it with optical positioning data to construct a three-dimensional alignment degree map.
Conclusion
Alignment detection technology is evolving from single geometric measurement to multi-physics field coupling analysis. In the field of lithium-ion start-stop batteries for motorcycles, through three breakthroughs - high-precision online detection (such as 5μ m-level CCD), material and process collaborative optimization (such as pre-loading ripple design), and intelligent early warning systems (such as digital twin models) - the alignment of electrode sheets has been controlled within ±30μm, providing a core guarantee for battery safety in high-vibration scenarios. In the future, with the popularization of solid-state electrolyte technology, alignment detection may be deeply integrated with the analysis of interface ion transport characteristics, opening up a new dimension of quality control in battery manufacturing.
RELATED BLOG
START-STOP LITHIUM battery
Enov start-stop battery is designed to provide excellent performance for high-demand start-stop vaehicles. It adopts the third-generation intelligent lithium platform architecture to achieve technological breakthroughs in core indicators such as cycle life, environmental adaptability and energy density. Compared with the traditional lead-acid battery system, the energy efficiency is increased by 210%, the cycle life is extended by 8-10 times, and the monthly self-discharge rate is controlled within 3%. Enov's unique low-temperature battery technology makes a breakthrough in achieving stable output in the whole climate domain from -30℃ to 65℃, maintaining more than 90% of the effective capacity release under extremely cold conditions (-30℃), and maintaining 90% of the capacity in high temperature environments (65℃).
The start-stop battery series products cover the mainstream voltage platform of 12V/24V/48V, and support flexible configuration of LFP (lithium iron phosphate) and NCM (lithium nickel cobalt manganese oxide) dual-material system. All models adopt modular design to support customization of different model specifications. Enuo engineering and technical team to provide full cycle technical service support, if you need, please contact us.
Other products
UAV BATTERY
LITHIUM ENERGY STORAGE BATTERY
QUICK INQUIRY
FAQ
Access to high frequency technical questions with one click, get accurate answers on product application, after-sales policy and customization process.
Service and Support
Get the latest product specifications, explore professional OEM/ODM customization services, click to open exclusive technical support and production solutions.
Become a Partner
We sincerely invite resources to interconnect, work together for win-win development, and immediately open a new chapter of strategic cooperation!