Assessment of production factors in the manufacturing of lithium-ion batteries: case study of Gelon LIB equipment

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Introduction Modern lithium-ion batteries (LIB) are a key component of next generation energy systems [1]. Optimizing the LIB production process in terms of safety [4], cost-effectiveness [5] and environmental sustainability [6] is particularly important, requiring a comprehensive and detailed analysis of each step [7]. The production of LIB is a multi-stage process with risks: chemical hazard of components, fire and explosion hazards, mechanical injuries, exposure to nanoparticles [4, 8-13]. Existing studies are often fragmented and do not offer a holistic risk management system for all technological stages [14-19]. The introduction of automatisation to minimize the human factor is of particular importance [20]. However, the approaches proposed in most existing papers often focus either on a limited list of technological stages [4, 8-13], or on individual safety aspects [14-19], without integration into a single multi-level management system. The paper [21] describes a risk management system for all stages of the process but does not include a detailed analysis of each stage in the production of a lithiumion battery taking into account all possible risk factors. Thus, unlike the published papers, this study offers a cross-sectional step-by-step analysis of the entire supply chain, which allows for the identification of interlinkages between risks at different stages and the development of measures to minimize them. This work thus fills the gap between fragmentary hazard assessments and a comprehensive risk management system that is suitable for direct implementation in real-world battery production. The aim of the study is to provide a comprehensive analysis of production risks at all stages of LIB manufacturing and to develop practical recommendations for creating an effective safety system. Research methods The methodology is based on a systematic analysis of the technological process of LIB production. Methods of risk analysis, comparative assessment of manual and automated operations, analysis of technical characteristics of specialized equipment on the example of Gelon LIB equipment were used. The process included key steps: preparation of the electrode mixtures, manufacture of the electrode, stack assembly and battery. Detailed description of the stages of production of LIB is provided in additional materials. Results The greatest risks during the preparation of an electrical mixture are dust and chemical factors, as well as the risk of mechanical injury (Table 1). Based on the results of the evaluation, risk reduction measures have been developed, including local ventilation systems, PPE (respirators FFP2/FFP3, chemically resistant gloves), earthing, locking, parameter control. Ensuring a safe working environment requires strict individual and collective protection measures, monitoring of the operating environment and regular training of staff. Implementation of the proposed recommendations will minimize professional risks, reduce the likelihood of accidents and ensure stable quality of products. In the electrode manufacturing phase, the greatest risks are mechanical injuries caused by rolling and cutting devices, thermal burns during drying (~120°C), exposure to solvent evaporation (Table 2). Proposed key protection measures include safety fences and locks, ventilation, heat-resistant gloves and FFP3 respirators, and vibration insulation. The electrode manufacturing process is thus characterized by a complex of hazardous factors, among which mechanical and thermal risks as well as exposure to harmful substances are the most significant. Special attention should be paid to collective protection equipment and the provision of quality personal protective equipment for workers. Regular monitoring of equipment and training activities for personnel are mandatory conditions to maintain a safe production process. Table 1. The electrode mixture preparation: results of the production factor assessment and risk mitigation measures Weighing of components (scales) Air dustiness Graphite, acetylene black, mixed lithium oxides Irritation to respiratory tract, risk of explosion (soot) Use of exhaust ventilation, PPE (respirator, gloves) Skin contact CMC, SBR, PVDF, NMP Skin irritation, allergic reactions Use of special clothing and gloves Static electricity Dry powders (graphite, soot) Sparking, risk of fire Equipment grounding, antistatic treatment Loading components into the mixer (planetary vacuum mixer GN-PM-5L) Mechanical injury Working with a mixer Pinching, hands caught in moving parts Locking the lid during operation, training, instructions Dust emission Filling with dry components Air pollution, explosion hazard Vacuum dust removal, local ventilation Stirring for several hours Noise Mixer operation Hearing impairment with prolonged exposure Using noise-canceling headphones Vibration Movement of mixer mechanisms Discomfort, operator fatigue Equipment condition monitoring, vibration isolation Heating the mixture Friction of components Change in reagent properties, risk of overheating Temperature control, mixing time limitation Control of the viscosity of the electrode mixture (viscometer) Contact with chemicals Mixture samples Irritation of skin and/or mucous membranes Use of gloves and glasses Measurement errors Incorrect calibration Product defect Regular inspection of equipment Source: compiled by R.G. Akhtyamov, A.V. Shikhovtseva, L.E. Kalugin, E.Yu. Evshchik. Table 2. The electrode manufacturing: results of the assessment of production factors and risk mitigation measures Installing a foil roll into the electrode mixture application machine (GN-C300 electrode mixture application and drying device) Mechanical injury Working with foil rolls Cuts, pinched fingers Use of protective gloves, training in handling materials Static electricity Dry foil Sparking, risk of fire Equipment grounding, antistatic coatings Roll centering error Incorrect installation Foil breakage, equipment downtime Loading control, automatic guides Application of electrode mixture to foil and drying (GN-C300) Exposure to high temperatures Drying at 120°C Burns, equipment overheating Furnace thermal insulation, temperature control, PPE (heat-resistant gloves) Solvent evaporation Drying the electrode mixture Respiratory tract irritation, toxic effects Exhaust ventilation, respirators (class A1 or A2) Contact of the mixture with skin Application of electrode paste Skin irritation, allergic reactions Protective gloves, workwear Rolling of electrode rolls on rollers (Rollers GN-HR-200) Mechanical injury Drawing into rolls Severe limb injuries Access lock during operation, emergency stop buttons Noise and vibration Operation of the rollers Hearing loss, fatigue Noise-canceling headphones (SNR ≥ 25 dB), vibration isolation Deformation of electrodes Uneven pressure Defective products Roller gap adjustment, quality control Cutting electrode rolls into sheets (GN-S 200P electrode cutting machine) Cuts and injuries Sharp edges of foil Hand injuries Use of protective gloves, automatic material feed Cutting errors Material displacement Product defect Positioning control, precision sensors Cutting sheets into electrodes of the required size (GN-S500 electrode cutting device) Contact with moving blades Operation of a guillotine cutter Finger injuries Protective covers, two-button switch Formation of metal dust Cutting foil Respiratory tract irritation Dust collection system, respirators Source: compiled by R.G. Akhtyamov, A.V. Shikhovtseva, L.E. Kalugin, E.Yu. Evshchik. During the battery stack assembly phase, significant differences in risk levels between manual and semi-automated production methods were identified (Table 3). Manual assembly implies high risk of injury, electrostatic discharge, defect due to human factor. Switching to semi-automatic assembly (GN-DP200S) reduces the risks of injury, defect and electrostatic effects but adds the risk of automation failures and noise. Table 3. The stack assembly: results of the assessment of production factors and risk mitigation measures Manual assembly of a stack (form made of plexiglass) Mechanical damage Sharp edges of electrodes, improper handling of foil Cuts, minor finger injuries Use of protective gloves (nitrile/antistatic), training in work safety rules Static electricity Dry materials (separator, electrodes) Sparking, risk of damage to sensitive components Workplace grounding, antistatic wristbands Assembly errors Incorrect placement of electrodes and separator Short circuit, product defect Visual control, use of templates Exposure to dust/ particles Metal and polymer particles Irritation of skin and respiratory tract Work in a clean area, use a respirator (FFP1) Semi-automatic stacking machine (semi-automatic stacking machine GN-DP200S) Mechanical injury Working with moving parts of the device Pinched fingers, injuries Access lock during operation, two-hand control Automation errors Electrode/separator supply failure Incorrect assembly, defective Position control sensors, periodic equipment testing Electrostatic discharges Automatic stacking of dry materials Damage to electronics, risk of fire Anti-static coating of equipment, humidity control (no more than 10%) Noise Operation of the device mechanisms Increased operator fatigue Using headphones (SNR ≥ 20 dB) Source: compiled by R.G. Akhtyamov, A.V. Shikhovtseva, L.E. Kalugin, E.Yu. Evshchik. The risk analysis carried out shows the clear advantage of semi-automated assembly method both in terms of production safety and product quality stability (Table 4). However, even with the use of automated equipment, there is still a need for strict safety measures and regular monitoring of the condition of the machine. The manual assembly method should be considered as a temporary or fallback solution, which is acceptable only if automated lines cannot be used and enhanced security measures are in place. Table 4. Comparative risk assessment for two assembly options Criterion Manual assembly Semi-automatic assembly Risk of injury High (contact with sharp edges) Medium (restricted access to hazardous areas) Risk of defects High (human factor) Low (automated control) Electrostatic risks Medium Low (best control) Performance Low High Operator dependency Critical Minimum Source: compiled by R.G. Akhtyamov, A.V. Shikhovtseva, L.E. Kalugin, E.Yu. Evshchik. Implementation of the proposed recommendations would significantly reduce occupational risks, reduce the number of industrial marriages and create safe working conditions regardless of the chosen method of assembly. Particular attention should be paid to the gradual transition from manual operations to automated processes, which is the most effective way to improve both safety and overall productivity in an enterprise. In the final stage of battery manufacturing, the most dangerous are electrolyte operations (LiPF6), which require work in an argon box due to the risk of producing toxic HF (Table 5). Also critical: noise and burns during ultrasonic welding, overheating during vacuum drying, risks of short circuit in testing. Proposed measures include sound-absorbing skins, electrolyte injection robotization, multi-level thermal control, and a complete set of PPEs. Table 5. The battery manufacturing: results of the assessment of production factors and risk mitigation measures Preparing a laminated aluminum case (GN-S230F case forming machine) Mechanical damage Sharp edges of aluminum foil Hand cuts while molding the body Use of protective gloves (cut-resistant) Deformation of the body Incorrect device setting Product defect Control of molding parameters, equipment calibration Ultrasonic welding of nickel terminals (ultrasonic welding GN-2500) Noise and vibration Operation of an ultrasonic welding machine Hearing damage, operator fatigue Noise-canceling headphones (SNR ≥ 25 dB) Thermal exposure Heating the welding zone Burns due to careless handling Heat-resistant gloves, protective screens Poor connection Incorrect welding parameters Reduced conductivity, defect Welding quality control, regular equipment inspection Vacuum drying of stack (vacuum drying oven) Overheating of components High drying temperature Degradation of electrodes, ignition Temperature control, automatic shutdown when overheating Vacuum depressurization Cabinet malfunction Moisture ingress, product defects Regular equipment maintenance, vacuum control sensors Sealing the housing (GN-HS200 sealing device) Thermal burns Hot surfaces during sealing Skin burns Heat-resistant gloves, automatic pliers Leaky seam Incorrect sealing parameters Electrolyte leakage, defective Seam quality control, visual and instrumental control Filling the argon box with electrolyte (argon box, GN-VS300 impregnation device) Electrolyte exposure Contact with LiPF6 Chemical burns, toxic Full set of PPEs (gloves, and solvents effects glasses, apron), exhaust ventilation Table 5, ending Risk factor Source Possible consequences Risk reduction measures Argon leak Depressurization of the box Suffocation, loss of inert atmosphere Air composition monitoring sensors, emergency ventilation Vacuuming and final sealing (GN-HS200V) Residual gases Incomplete vacuum Bulging of the case, decreased capacity Vacuum degree control Reheating the case Sealing process Deformation of the body Precise temperature control Electrochemical tests (Neware BTS4000-5V20A) Short circuit Incorrect connection Fire, equipment damage Staff training, connection testing Battery overheating High testing currents Thermal runaway, ignition Temperature control, automatic shutdown Source: compiled by R.G. Akhtyamov, A.V. Shikhovtseva, L.E. Kalugin, E.Yu. Evshchik. Discussion Analysis shows that the safety of LIB production cannot be ensured by precise measures. A systemic approach is required that integrates three key principles: Maximum automation of critical hazardous operations (electrolyte work, welding) to prevent direct contact of personnel with hazards; Implementation of multi-level monitoring of parameters (temperature, humidity, dust, air composition) in real time; Comprehensive protection of personnel, combining modern engineering solutions (locking, ventilation), adequate PPE and continuous training. The feature of this study is its phasing and practical orientation. In contrast to works that consider individual risks, here is proposed a holistic management system for the entire process chain, confirmed by a comparative analysis of the effectiveness of different assembly methods. Moving to automated lines is the most efficient way to simultaneously improve safety, quality and productivity. Conclusion The research allowed us to systematise key aspects of lithium-ion battery production, with particular attention to the analysis of production risks at each stage of the process. Electrolytes, ultrasonic welding and drying operations requiring special protection measures have been identified as the most safety-critical operations. The results of the study demonstrate that modern approaches to organizing battery production should be based on three key principles: maximizing automation of critical hazardous operations, implementing multi-level monitoring systems of parameters and comprehensive protection of personnel. The combination of technical solutions and organizational measures proved particularly effective. The practical significance of the work lies in the developed set of recommendations on optimization of technological processes from the point of view of safety, choice of means of individual and collective protection, as well as organization of quality control system and occupational safety. Implementation of the proposed measures would significantly improve safety and efficiency in the production of lithium-ion batteries while reducing production costs. Generally, the study confirms that only a systemic approach that takes into account all aspects of production, from raw material selection to final testing, can ensure competitive and safe battery manufacturing.

About the authors

Rasul G. Akhtyamov

Emperor Alexander I St. Petersburg State Transport University

Email: ahtamov.zchs@gmail.com
ORCID iD: 0000-0001-8732-219X
SPIN-code: 2812-3782

Ph.D. in Engineering (Candidate of Technical Sciences), Associate Professor, Department of Technosphere and Environmental Safety

9 Moskovsky pr., Saint Petersburg, 190031, Russian Federation

Anna V. Shikhovtseva

Federal Research Center for Problems of Chemical Physics and Medicinal Chemistry of the Russian Academy of Sciences

Email: dissovet04@icp.ac.ru
ORCID iD: 0000-0003-4058-2968
SPIN-code: 5367-2937

Junior Research Fellow, Laboratory of Solid-State Electrochemical Systems

1 Academician Semenov Ave., Moscow Region, Chernogolovka, 142432, Russian Federation

Leonid E. Kalugin

Federal Research Center for Problems of Chemical Physics and Medicinal Chemistry of the Russian Academy of Sciences

Email: kleo2712@yandex.ru
ORCID iD: 0009-0003-9507-1185
SPIN-code: 5657-5774

Ph.D. in Chemistry (Candidate of Chemical Sciences), Engineer, Laboratory of Materials and Device Technologies for Electrochemical Power Sources

1 Academician Semenov Ave., Moscow Region, Chernogolovka, 142432, Russian Federation

Elizaveta Yu. Evshchik

Federal Research Center for Problems of Chemical Physics and Medicinal Chemistry of the Russian Academy of Sciences

Author for correspondence.
Email: liza@icp.ac.ru
ORCID iD: 0000-0002-3562-8805
SPIN-code: 5375-9184

Ph.D. in Chemistry (Candidate of Chemical Sciences), Senior Research Fellow, Laboratory of Solid-State Electrochemical Systems

1 Academician Semenov Ave., Moscow Region, Chernogolovka, 142432, Russian Federation

References

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