In the context of global “dual-carbon” strategies, the push for green, eco-friendly, and low-carbon lifestyles has made energy conservation and emission reduction a priority across industries. Energy storage technology is widely recognized as a critical component in the power grid’s operational chain—encompassing generation, transmission, distribution, consumption, and storage—serving as a core pillar for renewable energy development. It is fundamental to building a “clean, low-carbon, safe, and efficient” modern energy system and driving transformations in energy production and utilization. With the construction costs of energy storage systems approaching breakeven points, as modeled by research institutions, the expansion of energy storage is essential for enhancing the flexibility, economy, and security of traditional power systems. Consequently, the energy storage battery module, as the core unit of energy storage systems, faces surging demand, necessitating a shift from discrete, low-automation production modes to highly automated, efficient manufacturing processes.
Current production of energy storage battery modules is plagued by issues such as unstable welding quality—leading to defects like blowholes and cold welds—and inefficiencies in discrete production models, including disordered processes, high labor intensity, and low throughput. To address these challenges, we have developed a modular assembly and testing production line for energy storage battery modules. This line integrates key processes through a double-speed chain system, enabling automated, continuous flow from cell inspection to finished module testing. The modular design allows four core units—cell detection, module pressing, module welding, and module testing—to operate both as an integrated line and independently, minimizing downtime from individual failures. By incorporating advanced technologies like pole laser cleaning, composite laser welding, and negative pressure dust removal, we aim to resolve welding defects and boost product quality. Our automated line eliminates manual handling and process confusion, significantly improving productivity. This article details the design, implementation, and validation of this production line, emphasizing its impact on efficiency and quality for energy storage battery manufacturing.
The energy storage battery module primarily consists of a housing, cover plate, front end plate, battery cells, fin separators, a CCS (Cell Contact System) harness assembly, and a Battery Management Unit (BMU). These components are assembled to form a robust and reliable unit for energy storage applications. In our design, cells and fin separators are alternately stacked within the housing, with the CCS harness assembly installed over the cells. Welding then connects the busbars of the CCS harness to the cell poles to establish electrical circuits, followed by assembly of the BMU, terminal blocks, and other accessories. Finally, the module undergoes comprehensive electrical testing, including voltage, internal resistance, insulation impedance, and withstand voltage checks.
The production workflow involves several key steps: automated cell feeding, cell performance testing and screening, cell stacking into the housing, module pressing and monitoring, pole addressing, polarity detection, pole cleaning, busbar welding, post-weld inspection, insulation testing, voltage and internal resistance measurement, communication testing, and final inspection. Each step is critical to ensuring the reliability and performance of the energy storage battery module. Below, we outline the core processes in detail, highlighting how our modular line optimizes each stage.
| Process Step | Description | Key Control Parameters |
|---|---|---|
| Cell Testing | Measures voltage, internal resistance, and voltage difference of individual cells to filter out defects. | Voltage tolerance: ±2 mV; Internal resistance deviation: <5% |
| Pole Laser Cleaning | Removes oxides and contaminants from cell poles using laser ablation to reduce welding defects. | Laser power: 50-100 W; Scanning speed: 100-200 mm/s |
| Busbar Laser Welding | Joins busbars to cell poles using composite laser welding for high-strength, low-defect connections. | Welding speed: 10-20 mm/s; Effective weld depth: ≥1.1 mm |
| Module Performance Testing | Conducts electrical tests (e.g., insulation,耐压) to validate module integrity and safety. | Insulation resistance: >100 MΩ; Withstand voltage: 3000 V AC for 60 s |
Our modular production line is structured around four interconnected units, linked by a double-speed chain conveyor to enable seamless, single-piece flow. This design ensures that energy storage battery modules move continuously from raw cells to tested products, with each unit performing specialized functions. The modularity allows for flexibility; if one unit requires maintenance, others can operate independently, preventing full line stoppages. Below, we delve into the design of each unit.
The cell detection unit comprises three stations: cell feeding, OCV (Open Circuit Voltage) testing, and module stacking. In the feeding station, a robotic arm picks cells from storage trays and places them into conveyor slots. The OCV station uses a three-axis gantry with probes to contact the cell poles, measuring voltage and internal resistance. Data is uploaded to a central server and compared against baseline values to assess cell health. Approved cells proceed to the stacking station, where operators visually inspect them and assemble them into modules on a stacking cart. Safety features, such as fencing and infrared sensors, ensure operator protection during automated operations. This unit is crucial for filtering out substandard cells early, preventing downstream issues in energy storage battery assembly.
The module pressing unit includes stations for module loading, polarity detection, and pressing. A gantry crane transfers modules from transport carts to line pallets, which are then conveyed via the double-speed chain. At the polarity detection station, a CCD camera on a three-axis gantry scans each cell to identify positive and negative poles, verifying correct stacking orientation. Data is sent to the central server for validation. In the pressing station, modules are compressed to design dimensions, with end plates installed to secure the stack. Pressure sensors monitor real-time force during pressing, with alarms set for limits to prevent cell damage. This process controls cell expansion during operation and ensures precise alignment for subsequent welding. The integration of these stations enhances consistency in energy storage battery module assembly.
The module welding unit is the core of quality assurance, featuring stations for pole addressing, pole cleaning, CCS harness installation, laser welding, post-weld inspection, and rejection handling. At the addressing station, a CCD-based system maps the coordinates of each cell pole relative to the module, sharing this data with downstream stations. The cleaning station uses laser sintering to remove oxides and contaminants from poles, reducing hydrogen generation during welding—a common cause of blowholes. The installation station involves manual placement and pre-fixing of the CCS harness. Welding employs composite laser technology, where an outer ring laser preheats the area and an inner ring performs deep penetration welding, minimizing spatter and defects. A negative pressure dust removal system extracts fumes and spatter, preventing internal short circuits. Post-weld inspection checks each weld for voids, cracks, or misses, with defective modules routed to a rejection station. This unit significantly boosts the reliability of energy storage battery connections.
The module testing unit handles final assembly and validation, including BMU installation, EOL (End of Line) testing, communication testing, and final inspection. At the BMU station, operators attach the BMU and terminal blocks, with torque monitoring for screws. The EOL station conducts comprehensive electrical tests: voltage and internal resistance are measured to ensure circuit integrity, insulation impedance is checked for safety, and withstand voltage tests verify dielectric strength. The communication station interfaces with the BMU to monitor cell voltages and temperatures, analyzing differentials for anomalies. Finally, the inspection station performs visual checks, applies quality labels, and offloads finished modules. This unit ensures that every energy storage battery module meets stringent performance criteria before shipment.
A Manufacturing Execution System (MES) supports the entire line, comprising a host computer, terminal monitors at each station, and display screens. Operators scan codes to input production data, which the host processes for real-time tracking. Key MES functions include: process management, where assembly instructions and device statuses are called based on production orders; data acquisition and retrieval, collecting test results,工艺 parameters, operator info, and fault logs; and electronic dashboards, showing metrics like planned vs. actual output, yield rates, and equipment status. This system enables traceability and quality control across the energy storage battery production lifecycle.
| Metric | Discrete Production Mode | Modular Automated Line | Improvement |
|---|---|---|---|
| Production Cycle Time per Module | ~9 minutes | ~3 minutes | 3× faster |
| Operator Count | 12 persons | 3 persons | 9 persons reduced |
| Product Qualification Rate | ~98.5% | ≥99.88% | ~1.38% increase |
| Line Availability | Low due to bottlenecks | High with modular redundancy | Significant uptime gain |
To validate our design, we conducted extensive testing on both the overall line and key processes. The integrated line, with its double-speed chain, achieves continuous flow, producing energy storage battery modules at a rate of one module every 3 minutes for a 24-cell configuration. This represents a threefold efficiency gain over single-station modes, with a reduction of nine operators. The modular setup proved resilient; during simulations, a fault in one unit did not halt the entire line, as other units continued operating. We attribute this robustness to the independent control systems and standardized interfaces between modules.
A critical focus was on pole laser cleaning and its impact on welding quality. The cleaning process uses high-energy laser beams to ablate surface contaminants, reducing hydrogen sources that cause porosity. We evaluated cleaning effectiveness through metallographic analysis and tensile testing. The weld cross-sections showed that cleaned poles had fewer气孔 and deeper penetration. Tensile tests involved pulling welded samples until failure; results indicated that cleaning increased average pull force by approximately 8.7%. The relationship between cleaning parameters and weld strength can be modeled as:
$$F_c = F_0 \cdot (1 + \alpha \cdot P_{laser} \cdot v^{-1})$$
where \(F_c\) is the pull force after cleaning, \(F_0\) is the baseline force without cleaning, \(\alpha\) is a material constant, \(P_{laser}\) is laser power, and \(v\) is scanning speed. Our optimal parameters were \(P_{laser} = 80\,W\) and \(v = 150\,mm/s\), yielding consistent improvements for energy storage battery connections.
| Sample Condition | Sample 1 (kN) | Sample 2 (kN) | Sample 3 (kN) | Average Force (kN) |
|---|---|---|---|---|
| Uncleaned | 2.996 | 2.895 | 2.766 | 2.885 |
| Laser-Cleaned | 3.108 | 3.127 | 3.146 | 3.127 |
For laser welding, we employed composite technology to minimize defects. The weld area is critical for current-carrying capacity, determined by the effective cross-sectional area. Using a ring-shaped beam, we set parameters to achieve an effective weld width of 2 mm and a weld center trajectory of 11 mm. The minimum required cross-sectional area \(S_{min}\) for a discharge current \(I_{discharge} = 164\,A\) is calculated based on current density limits. Assuming a permissible current density \(J_{max} = 5\,A/mm^2\), we have:
$$S_{min} = \frac{I_{discharge}}{J_{max}} = \frac{164}{5} = 32.8\,mm^2$$
The actual weld area \(S\) for a circular trajectory with outer diameter \(D\) and inner diameter \(d\) is:
$$S = \frac{\pi (D^2 – d^2)}{4}$$
With \(D = 12\,mm\) and \(d = 10\,mm\), we get \(S = \frac{\pi (144 – 100)}{4} = 34.56\,mm^2\), which exceeds \(S_{min}\), ensuring sufficient载流量 for the energy storage battery module. Metallographic analysis confirmed effective weld depths \(\geq 1.1\,mm\), with pull tests showing failures in the base material rather than the weld, indicating superior strength. Over three months of operation, the qualification rate for welded modules exceeded 99.88%, demonstrating the efficacy of our approach.
The implementation of negative pressure dust removal during welding further enhanced quality. By instantly extracting particulates, we prevented insulation breaches and short circuits. The dust extraction efficiency \(\eta\) can be expressed as:
$$\eta = 1 – \frac{C_{out}}{C_{in}}$$
where \(C_{in}\) and \(C_{out}\) are particulate concentrations at the intake and exhaust, respectively. Our system achieved \(\eta > 95\%\), contributing to the high yield of energy storage battery modules.
In summary, our modular production line for energy storage battery modules integrates advanced automation and key technologies to address longstanding manufacturing challenges. By linking cell detection, pressing, welding, and testing units via a double-speed chain, we enable efficient, continuous flow production. The modular design offers flexibility and robustness, allowing units to function independently during maintenance. Through pole laser cleaning, composite laser welding, and dust removal, we have significantly reduced defects like blowholes and cold welds, pushing product qualification rates above 99.88%. The line triples productivity compared to discrete modes and reduces labor by nine persons, yielding substantial economic benefits. This solution not only meets the growing demand for energy storage battery systems but also sets a benchmark for automated, high-quality manufacturing in the renewable energy sector. Future work will focus on integrating AI for predictive maintenance and further optimizing cycle times to scale production for larger energy storage applications.
The success of this line underscores the importance of modularity in modern manufacturing, particularly for complex products like energy storage battery modules. As the world transitions to greener energy, such innovations will be pivotal in ensuring reliable, cost-effective, and scalable production. We believe our design provides a replicable model for industries seeking to enhance automation and quality in energy storage battery assembly, contributing to the broader goals of sustainability and energy security.