Production Of Lithium-ion Cells Research Articles

Environmental and economic assessment of a higher energy density and safer operation lithium-ion cell for stationary applications

Europe has made significant progress in decarbonizing the planet by increasing the share of renewable energy, with solar, wind, and water being the primary sources of renewable electricity. Energy storage systems, especially batteries, are critical in integrating high shares of renewable energy and ensuring grid stability. Lithium-ion batteries are the preferred choice due to their acceptable cycle life, safe operation at high voltages, and high energy density. However, there is still room for improvement increasing energy density, safety during operation and producing sustainable batteries. This study has identified new materials that can be incorporated into a high-voltage Co-free spinel cathode cell to enhance its electrical performance and ensure safe operation. These materials include a silicon-containing carbonaceous composite as a long-life high-capacity anode active material and a custom-made porous separator based on PVDF, which facilitates the development of a gel-type electrolyte, improving the cell's safety and providing higher cyclability performance. The introduction of the new silicon-containing carbonaceous composite and the PVDF- based membrane is studied in this work from an environmental and economic perspective. An environmental study is performed using the LCA tool to evaluate the sustainability of the Lithium-ion cell production process. An economic study is also performed to calculate the cost of the cells, including raw materials, transport, production process, and externalities costs related to the production process. The Almagrid cell, which has a safer porous separator and an anode made of silicon-containing carbonaceous composite, showed enhanced safety and similar environmental performance compared to the reference cell. However, Almagrid technology will have the potential to improve its sustainability and cost when in-house synthesized components are optimized and scaled up becoming commercially available.

Dry Battery Electrode Manufacturing Enabled By Continuous Powder Mixing

Lithium-Ion Battery electrode manufacturing is a cost- and energy-intensive process that usually relies on the use of a hazardous and expensive solvent, N-methyl-2-pyrrolidone (NMP), for cathodes. After coating the battery-slurry to a current collector, the solvent needs to be evaporated to obtain a porous electrode suitable for the use in a Lithium-Ion Battery. The solvent is a processing material and unwanted in the final product. In fact, solvent residues can fuel parasitic side-reactions within the battery cell and hence deteriorate battery lifetime and safety. The utilization of NMP in battery production plants demands costly labor protection and explosion safety measurements during mixing and coating and necessitates a highly energy and floor-space demanding drying step using thermic drying ovens of up to 100 meters.[1] For ecological and economic reasons, NMP is not emitted in large-scale production facilities, but condensed and recycled by distillation. The NMP-recovery system adds additional floor space and energy demand to the production site. The drying and solvent recovery can account for up to 39% of the total energy demand of a Lithium-Ion Battery Cell production and therefore produce significant CO2 emissions.[2] A solvent-free, dry electrode manufacturing that eliminates the use of solvents hence reduces the floor space, energy demand and cost of a production plant and eases safety and environmental concerns. Different approaches have been reported in the literature to put dry coating into practice,[3],[4] yet most strategies, for example spray coating or brush coating, lack of a feasible implementation into large scale production. In contrast, a dry coating approach that is sometimes referred to as the Maxwell-Process is, according to media reports, currently installed at Tesla’s Gigafactories in Berlin and Austin.[5] In fact, a publicly available teardown of a Tesla 4680 battery cell hints that a dry coated anode could already be used in commercial vehicles.[6] Compared to the state-of-the-art electrode manufacturing process, dry coating requires different polymeric binder systems that form spiderweb-like structures of fine fibrils connecting the electrochemical active particles and the conductive additive particles. PTFE is highly suitable since it is stable towards typical electrolytes and cathode materials and is known to easily form fibrils. These properties are also utilized to produce expanded PTFE membranes like Gore-Tex. The fibril-network in the battery context is primarily formed by a high-shear dry mixing process. The powder mixture is then compressed to a free-standing electrode film (powder-to-film) by a heated rolling mill (calender) and the resulting film is ultimately laminated to a current collector foil (film-to-foil). We demonstrate that a twin screw-extruder can be used to tune the degree of binder-fibrillation during dry-mixing of NMC-based cathode mixtures. Extrusion based mixing allows to use powder mixtures with little amounts of PTFE binder (1 wt%) to produce self-supporting, free-standing cathode films and, ultimately, battery electrodes with high flexibility and sufficient mechanical stability. We show a superior rate-performance and cycling-stability of single-layer pouch cells with dry-coated cathodes compared to cells with wet coated reference electrodes of likewise composition and electrode design. Possible causes for the improved performance focusing on microstructural electrode properties are discussed.[1] Westphal, Bastian G.; Kwade, Arno (2018): Critical electrode properties and drying conditions causing component segregation in graphitic anodes for lithium-ion batteries. In: Journal of Energy Storage 18, S. 509–517.[2] Erik Emilsson, Lisbeth Dahllöf (2019): Lithium-Ion Vehicle Battery Production. IVL Swedish Environmental Research Institute.[3] Duffner, Fabian; Kronemeyer, Niklas; Tübke, Jens; Leker, Jens; Winter, Martin; Schmuch, Richard (2021): Post-lithium-ion battery cell production and its compatibility with lithium-ion cell production infrastructure. In: Nat Energy 6 (2), S. 123–134.[4] Verdier, Nina; Foran, Gabrielle; Lepage, David; Prébé, Arnaud; Aymé-Perrot, David; Dollé, Mickaël (2021): Challenges in Solvent-Free Methods for Manufacturing Electrodes and Electrolytes for Lithium-Based Batteries. In: Polymers 13 (3).[5] https://www.tagesspiegel.de/berlin/tesla-coup-mit-giga-berlin-neue-technologie-soll-wasserverbrauch-minimieren/27244032.html[6] https://www.youtube.com/watch?v=8WPPBhqeekw Figure 1

Economic potential assessment of multi-cell testing in lithium-ion cell production and electric vehicle application

Lithium-ion cells for electric vehicles are evaluated for their performance at different stages of their life cycle, with the initial characterization in cell production as part of an end-of-line test being the most crucial due to the quality classification and scope. This paper presents an economic potential analysis of a novel multi-cell testing method for the use in sustainable and smart cell quality testing which economizes on the number of test channels required. Using a cost comparison and net present value method assessed for two feasible deployment scenarios, it is shown that the cost parity point compared to conventional single-cell procedures can be reached with only four series-connected cells. Overall, both multi-cell scenarios yield a cost reduction of ∼42 % per tested cell. The percentage shares of the cost categories redistribute moderately when switching from single-cell to multi-cell testing in a smart factory, with procurement costs of the battery cyclers with up to 43 % of the total costs representing the most significant share. Additional benefits can be expected with the method assuming maintenance schedules on a per-device basis. At 5% to 31 % of the costs, the energy expenses represent a significant lever for the profitability of the characterization and the thus economically viable scope of cell characteristics examined. Prospects are given for multi-cell testing in later life cycle phases, considering the re-evaluation of battery performance in operation during service checks and the remanufacturing at the original equipment manufacturers or service providers in 2nd life applications.

A Study of Stress Evolution and Deformation in Cylindrical Cells, from before Manufacturing to End of Life

The mass production of lithium-ion cells involves applying a range of manufacturing processes to a range of materials. These processes inevitably result in residual stresses within the individual materials, which when abetted by operational stresses can cause deformation and fracture of the componentry. This contributes to the degradation of electrochemical properties, device performance, and durability of the cells; leading ultimately to cell failure. This experimental study is concerned with determining the mechanical degradation of componentry within cylindrical cells. Mechanical degradation was evaluated for commercial cells using x-ray tomography, mechanical testing and microscopy. Nanoindentation testing was used to characterise mechanical changes in the foil material in three conditions: before cell manufacture, after cell manufacture and after aging. This work represents a novel ex situ characterisation tool and a new approach to understanding degradation in electrochemical systems. Additionally, we anticipate this work to aide modelling of and controlling degradation within electrochemical systems.

Wetting and Inductivity in the Impedance Behavior of Large Lithium-Ion Cells

The wetting of the porous electrodes and the separator is crucial in the production of lithium-ion cells. Electrochemical impedance spectroscopy is able to measure and characterize the wetting. This paper p resents an equivalent circuit for commercial high-capacity cells and shows a method to analyze the wetting of these cells. The equivalent circuit includes an external inductance, a transmission line model (TLM) for the description of the pore impedance and, additionally, a TLM for the impedance of substrate foil inductance and contact resistance. Based on symmetric and full laboratory cells, the superposition of the impedance is discussed. Furthermore, the method to adjust the impedance and analyze the wetting is demonstrated on hard case cells with a capacity of 22 Ah. It is shown that, in addition to inductance for cables and electrode-external contacts, high-capacity lithium-ion cells build up inductance due to the electrode area in combination with the substrate foil. This inductance, together with the contact resistance, result in a characteristic hook in the Nyquist plot. A TLM describes and explains this behavior quite well. Additionally, the impedance of the cell is adjustable so that it corresponds to a laboratory cell in blocking conditions. Thus, the wetting of the separator and the wetting of the electrode become separately evaluable and calculable.

Lithium Drives EV, Grid Storage as Industry Scrambles To Fill Supply Deficit

What fossil fuel was to the industrial revolution, lithium is to today’s energy transition. Often referred to as the oil of the 21st century, this strategic commodity is essential to the manufacture of batteries, from the 35- to 100-kWh type that power electric vehicles (EVs) to grid-size 100-MW (and larger) battery energy storage systems (BESS) such as those at Tesla’s Gambit Energy Storage Park near Houston, whose power capacity is among the highest in the US. Because lithium-ion batteries charge quickly and last longer due to their higher power density, it is not surprising that as the energy transition picks up the pace, the demand for lithium is rapidly outstripping supply, leaving the industry scrambling to find new sources—whether that means opening new mines or devising new technologies to extract lithium from brines, including brines found in water produced from oil and gas operations. In the EV arena, Deloitte forecast a 29% compound annual growth rate in EV sales over this decade, predicting that EVs will comprise 32% of new car sales by 2030 with China commanding 49% of the market, Europe holding 27%, and the US at 14%. The US Environmental Protection Agency attributes 30% of US greenhouse-gas emissions to transportation, a fact that has prompted the automobile industry to shift into transformational mode to make this decade the tipping point when EVs become mainstream. Catching the Vibe at CES In her keynote at the 2022 Consumer Electronics Show (CES) in Las Vegas, Nevada, in January, General Motors CEO Mary Barra announced that in 2023, GM will launch production of its long-anticipated electric Chevrolet Silverado pickup truck, a move made possible by the company’s $35-billion investment strategy announced last summer to compete with Tesla. GM’s investment plan through 2025 targets, among other things, “on lining” four new, US-based lithium-ion cell production plants with a combined cell production capacity of 140 GWh/year, based on the company’s proprietary Ultium platform. Ultium Cells LLC, a joint venture with LG Energy Solution, announced in late January it would build its third plant in Lansing, Michigan. The JV is currently constructing plants in Lordstown, Ohio, and Spring Hill, Tennessee; the location of the fourth plant has yet to be announced. Back in Las Vegas, Sony grabbed headlines at CES by reaffirming it will open its own automobile unit, Sony Mobility Inc., in the spring of 2022, and Chrysler, a part of the Netherland’s Stellanis group, treated CES visitors to a look at its first EV concept car which is planned to launch in 2025. From that standing start, Stellanis said it expects to convert 70% of its European vehicle sales and 40% of its US sales over to the EV category by 2030.

Energy flow analysis of laboratory scale lithium-ion battery cell production

SummaryLithium-ion batteries (LIBs) have been proven as an enabling technology for consumer electronics, electro mobility, and stationary storage systems, and the steadily increasing demand for LIBs raises new challenges regarding their sustainability. The rising demand for comprehensive assessments of this technology's environmental impacts requires the identification of energy and materials consumed for its production, on lab to industrial scale. There are no studies available that provide a detailed picture of lab scale cell production, and only a few studies provide detailed analysis of the actual consumption, with large deviations. Thus, the present work provides an analysis of the energy flows for the production of an LIB cell. The analyzed energy requirements of individual production steps were determined by measurements conducted on a laboratory scale lithium-ion cell production and displayed in a transparent and traceable manner. For the comparison with literature values a distinction is made between the different production scales.

Post-lithium-ion battery cell production and its compatibility with lithium-ion cell production infrastructure

Lithium-ion batteries are currently the most advanced electrochemical energy storage technology due to a favourable balance of performance and cost properties. Driven by forecasted growth of the electric vehicles market, the cell production capacity for this technology is continuously being scaled up. However, the demand for better performance, particularly higher energy densities and/or lower costs, has triggered research into post-lithium-ion technologies such as solid-state lithium metal, lithium–sulfur and lithium–air batteries as well as post-lithium technologies such as sodium-ion batteries. Currently, these technologies are being intensively studied with regard to material chemistry and cell design. In this Review, we expand on the current knowledge in this field. Starting with a market outlook and an analysis of technological differences, we discuss the manufacturing processes of these technologies. For each technology, we describe anode production, cathode production, cell assembly and conditioning. We then evaluate the manufacturing compatibility of each technology with the lithium-ion production infrastructure and discuss the implications for processing costs. Tremendous research progress has been made in the development of post-lithium-ion batteries (PLIBs), yet there is little discussion on the manufacturing of these upcoming technologies. In this Review, the authors survey the current production status of several representative PLIBs and offer an industrial-scale manufacturing outlook.

Marking of Electrode Sheets in the Production of Lithium-Ion Cells as an Enabler for Tracking and Tracing

The production of lithium-ion batteries is highly complex and characterized by continuous as well as discrete material flows and processes. A first step towards controlling the complexity of battery production is to create transparency through data collection. Electrodes as one of the key elements in a battery cell play a decisive role for the battery performance. The allocation of production data to electrodes enables a detailed digital twin and an individual grading system. This paper presents a concept for the marking of electrode sheets and requirements on markers as well as on marking technologies due to boundary conditions.

All-solid-state lithium-ion and lithium metal batteries – paving the way to large-scale production

Challenges and requirements for the large-scale production of all-solid-state lithium-ion and lithium metal batteries are herein evaluated via workshops with experts from renowned research institutes, material suppliers, and automotive manufacturers. Aiming to bridge the gap between materials research and industrial mass production, possible solutions for the production chains of sulfide and oxide based all-solid-state batteries from electrode fabrication to cell assembly and quality control are presented. Based on these findings, a detailed comparison of the production processes for a sulfide based all-solid-state battery with conventional lithium-ion cell production is given, showing that processes for composite electrode fabrication can be adapted with some effort, while the fabrication of the solid electrolyte separator layer and the integration of a lithium metal anode will require completely new processes. This work identifies the major steps towards mass production of all-solid-state batteries, giving insight into promising manufacturing technologies and helping stakeholders, such as machine engineering, cell producers, and original equipment manufacturers, to plan the next steps towards safer batteries with increased storage capacity.

Cost Reduction Strategies for Lithium Ion Electrode Processing and Pouch Cell Formation Steps

For lithium ion batteries (LIBs) to take their place in widespread commercialization of hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and full electric vehicles (EVs), system cost must still be reduced by 2-3× to about $200 kWh. [1] Two important ways to achieve significant system cost reduction are to: 1) lower the electrode processing cost (elimination of costly organic solvents, increasing the cathode thickness, and reduction of primary solvent drying time); and 2) reduce the formation time associated with the anode solid electrolyte interface (SEI) layer.Purchasing and handling the N-methylpyrrolidone (NMP) solvent used in much of the electrode formulation and coating steps add unnecessary manufacturing cost to the LIB pack. In addition, more processing energy (heated air flow) is required to remove NMP during drying of the electrode coatings than other solvents (such as water and lower alcohols) with much lower boiling points and higher vapor pressures. NMP recovery involves significant capital expense since multiple condensers or distillation towers are needed, and its use adds to the cost of the coating line equipment in making it explosion proof. Cathode thicknesses, which currently limit the cell specific capacity (mAh/g on a total-unit-cell weight basis) and energy density and indirectly add to cell cost, should also be significantly increased, so much fewer inactive components (current collectors and separators) are required per cell.Electrode wetting and formation cycling also add significant process energy cost per kWh of usable energy, which is often neglected in LIB pack cost calculations. Furthermore, the wetting and formation steps are a huge process time bottleneck and add substantial capital cost to a LIB production plant. In a large-scale LIB manufacturing plant, the footprint associated with the wetting and formation steps can be as large as 20-25% of the entire layout.There have been two useful LIB cost studies presented recently by Argonne National Laboratory (ANL) [2] and TIAX, LLC, [3] but these studies consider the entire 18650 cell production process without much granularity on individual processing and fabrication steps. These cost models are also heavy on contributions from material, labor, and capital equipment without detailed consideration of process energy requirements. This paper will give a more in depth review of the process energy consumption associated with electrode processing and formation cycling, two particularly costly elements of lithium-ion cell production, and how manufacturing cost savings could be realized.The cell fabrication steps mentioned above contribute significantly to the current overall pack cost of $400-600/kWh and will be the focus of the calculations in this presentation. Formulation, coating, and drying aspects will be considered with respect to electrode processing cost, and wetting time and low-rate cycling will be addressed with respect to total cell formation time. This cost assessment approach will show the critical link between electrode processing aides, process energy consumption, and LIB pack cost. Initial calculations show that about 20% of the total battery pack cost can be saved by switching to aqueous electrode processing and doubling the electrode thicknesses. Acknowledgment This research at Oak Ridge National Laboratory (ORNL), managed by UT Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725, was sponsored by the Office of Energy Efficiency and Renewable Energy (EERE) Vehicle Technologies Office (VTO) Applied Battery Research (ABR) subprogram (Program Managers: Peter Faguy and David Howell).

The Impact of Intentionally Added Water to the Electrolyte in Li-Ion Cells

Electrolyte formulation is crucial to extending the lifetime and increasing the performance of lithium ion cells. Keeping moisture levels low (< 15 ppm [1]) has always been a standard in commercial lithium ion cell production which also increases the cost of electrolyte and cell manufacturing. The purpose of this study is to show the impact of small amounts of intentionally added water (100 – 2000 ppm) to the electrolyte impacts cell performance.Recently it has been shown that short term measurements of the coulombic efficiency and charge endpoint slippage rate coupled with storage and impedance measurements can give good indications of long term cycling performance [2-4]. In this study, wound LiCoO2/graphite, Li[Ni0.42Mn0.42Co0.16]O2/graphite and LiCoO2/Li4Ti5O12cells were made (similar to those in references 2-4) and filled with electrolytes containing additives such as vinylene carbonate [3, 5] and LiTFSI [4, 6] with and without intentionally added water to the electrolyte. Duplicate cells were made for both cycling on the High Precision Charger [7] and storage on an automated cycling/storage system [8] both built at Dalhousie University. Along with these short term measurements, impedance spectra were collected and long term cycling performance was evaluated. This presentation will discuss the impact of adding water with and without the presence of these additives in different cell chemistries along with other studies done on pouch cells containing intentionally added water in the electrolyte.One outcome of this work is that there appears to be no negative impact, and perhaps a positive impact in adding 1000 ppm water to LCO-graphite cells in the presence of the additives, VC and LiTFSI. This suggests that in the presence of these additives, water content specifications could perhaps be relaxed somewhat leading to an avenue for cost reduction. Long term cycling results on many of the cells are available to compare to the short-term, precision, measurements.Figure 1. A summary of data collected for LiCoO2/graphite cells, with and without both additives and water in the electrolyte, including charge transfer resistance (Rct), voltage drop during storage (V Drop), coulombic efficiency (shown as 1-CE) and charge endpoint slippage rate (Ch. Slippage).Figure 2. The charge endpoint capacity (top), discharge capacity (middle) and coulombic efficiency (bottom) versus cycle number for LiCoO2/Li4Ti5O12cells at both 30 (left) and 60°C (right) containing various amounts of added water in the electrolyte from 200 – 2000 ppm.

Integrated Product and Process Model for Production System Design and Quality Assurance for EV Battery Cells

The megatrend electric mobility induces a significant demand for high energy and high power secondary batteries. Currently lithium-ion technologies are the most promising solution for electrochemical energy storage in hybrid electric vehicles (HEV) and battery electric vehicles (BEV) [1; .Core factors that influence the quality, the performance and the cost of high energy lithium-ion batteries are production technologies, quality measurement techniques and quality management methods [3; . For this reason the Institute for Machine Tools and Industrial Management set up the Research Center for the Production of High-Energy Battery Cells (R-PHEB). In this research center production technologies are investigated according to industrial requirements. Research thrust areas are: first, process and assembly system design; second, quality assurance and management; and third, value chain analysis and design.The mass production of large lithium-ion cells for EV applications is an infant industry; new production technologies are often used in this field [. Hence, the influences of those processes on product properties are not known and the product quality can be evaluated only after the final production step. In order to obtain a resource efficient and economic production of lithium-ion cells, the correlations between the cell performance, the cell quality, the production processes and the assembly system design need to be revealed.This paper focuses on fundamental investigations of the process chain for the production of lithium-ion cells. It introduces a product-and a process-model, both of which specifically match the requirements in the field of battery production. The models can be used individually to describe the product structure or the process chain. Additionally they can be linked via a correlation matrix in order to visualize the dependencies between the requirement specifications of lithium-ion cells and the manufacturing processes (including process alternatives). Both models are based on a layered structure and contain information about battery cell design, battery type and production processes covering all tasks from coating the electrode coils to the start-of-operation of the cells.The product-model, the process-model and the correlation matrix will be implemented in a database, which in the future can be used for the methodical design of assembly systems as well as to investigate the correlations between process parameters and output quality. Furthermore, the database can assist when evaluating established process chains or preparing make-or-buy decisions in the context of battery cell production.

Complexity Management for the Start-up in Lithium-ion Cell Production

This paper presents the core of a quality management methodology for production chain optimization, applicable from early design stages of production systems to the production start-up, as well as its application in lithium-ion cell production. The entire methodology was presented before [1]. The results of the methodology's first step, which is based on process Failure Mode and Effects Analysis (FMEA), are briefly described since the collected correlations are the input for the further steps. This paper describes how these correlations are transferred into correlation matrices and then propagated over the entire production chain by means of multiple domain matrices (MDM). The resulting production chain MDM provides parameters with direct or indirect influences on the quality parameters of the final product. Furthermore, relevant parameters are selected by an iterative application of MDM based production chain analyses in combination with Pareto analysis and experimental investigations. Proceeding steps quantify the identified influences and derive set point values for the individual processes by means of a multivariate optimization of the final cell quality considering the entire production chain.

Design of Assembly Systems for Large-Scale Battery Cells

The social and technical trends regarding electro mobility and the turnaround in energy policy cause an increasing demand on large-scale and high-quality lithium-ion cells as core components for electrical storage systems. Within the production of lithium-ion cells, cell assembly has to deal with diverse challenges which result from product complexity and a lack of production experience. This paper covers the design of assembly systems for large-scale lithium-ion cells and presents the enhancement of conventional design processes by three add-on modules. The first one is an analysis of product structure and design focus points and is described in this paper. The modules two and three are outlined.

Laser Cutting in the Production of Lithium Ion Cells

Due to the current limiting factor of the energy storage alternative electrical drive (e-drive) concepts are still under development and improved battery production techniques are needed. Different research groups are investigating the influence of several production processes on the quality of the produced lithium ion battery cell. One investigated process is the cutting of the cell electrodes. This paper presents investigations on the influence of a laser cutting process on the cutting edge quality of copper and aluminum based electrode materials. The different process parameters are examined and the main influencing factors on the quality are determined to ensure an optimized processing rate.