Matthieu Dubarry

University of Hawaiʻi at Mānoa | UH Manoa · School of Ocean and Earth Science and Technology

Sodium‐ion batteries offer a promising alternative to lithium‐ion batteries by addressing ecological and economic challenges. However, to assess the applicability of these cells for different sectors, understanding aging behavior, including degradation modes, is crucial. This work presents a comprehensive aging analysis of 67 commercial sodium‐ion...

The development of commercial Na-ion battery cells for various energy storage applications has ramped up rapidly in the last three years. Currently, 18650 format cells from several manufacturers have been released for purchase through wholesalers, indicating that Na-ion cells may soon be ready for adoption into the grid, electric vehicles, and vari...

Lithium and sodium plating are inevitable when using negative electrodes with an electrochemical potential close to one of the charge carriers. Typical testing and modeling assume that plating occurs at 0 V when measured against the charge carrier. While this might be true under thermodynamic equilibrium, this is not true outside of steady state. T...

Commercial Na-ion batteries are becoming available with performance forecasted to be similar to that of their lithium counterparts. On the many diagnosis and prognosis techniques developed to characterize batteries in the past four decades, it is essential to assess how many could be directly transferred to Na-ion batteries. In particular, the degr...

This study evaluated three approaches for characterizing voltage relaxation in lithium-ion batteries: voltage vs. time, the derivative of voltage vs. time, and the second derivative of voltage vs. time. The first two are well-established approaches, whereas the third was never investigated to our knowledge. To assess the potential of each approach,...

Commercial Na-ion batteries are now becoming available with performance forecasted to be similar to that of their Lithium counterparts. On the many diagnosis and prognosis techniques developed for Li-ion batteries in the past four decades, it is essential to assess how many could be directly transferred to Na-ion batteries. In particular, the degra...

We are a team of three battery researchers and engineers who are working with The Electrochemical Society to develop an “electrochemical techniques and diagnostics for batteries” curriculum, comprised of an online course and an in-person workshop. With a combined 40+ years of experience working in battery research and engineering, ranging from acad...

Lithium and Sodium plating are inevitable when using negative electrodes with an electrochemical potential close to the one of the charge carrier. Typical testing and modeling usually assumed that plating occurs at 0V when measured against the charge carrier. While this might be true under thermodynamic equilibrium, this is not true outside of stea...

This study evaluated three approaches for characterizing voltage relaxation in lithium-ion batteries: voltage vs. time, the derivative of voltage vs. time, and the second derivative of voltage vs. time. The first two are well-established approaches, whereas the third was never investigated, to our knowledge. To assess the potential of each approach...

Blended electrodes are becoming increasingly more popular in lithium-ion batteries, yet most modeling approaches are still lacking the ability to separate the blend components. This is problematic because the different components are unlikely to degrade at the same pace. This work investigated a new approach towards the simulation of blended electr...

Accurate diagnosis of lithium-ion battery (LIB) degradation is critical for safe and reliable operation in real-world applications. In recent years, data-driven approaches powered by Machine Learning algorithms emerged as a promising solution, among which Deep Learning methods were proven to be effective for various tasks such as State of Charge an...

Lithium-ion batteries are widely used in applications from consumer electronic devices to stationary energy storage. Appropriate management of batteries is challenging due to limited data on their performance and materials degradation. Previous studies have focused on characterization of single cells under specific operating conditions. In the pres...

The ongoing usage of lithium-ion cells and packs in both stationary and mobile applications necessitates comprehensive tools and models to diagnose and prognose cell performance onboard. One of the main tasks of a battery management system is to infer the state of charge (SOC) and state of health (SOH) of batteries. SOC estimation is usually done b...

Temperature is an important parameter in electrochemical processes and battery operation; for instance, open circuit voltage and resistance values of cells are temperature sensitive. Several recent studies have shown temperature within battery packs are not uniform. This non-uniformity of temperature produces localized thermal gradients within cell...

The increasing growth of the second-hand electric vehicle market demands reliable methods for evaluating the state of health of deployed electric vehicle batteries. Among these methods, incremental capacity analysis is a commonly used technique for state of health evaluation via the quantification of degradation modes. While the optimal conditions...

The diagnosis and prognosis of PV-connected batteries are complicated because cells might never experience controlled conditions during operation as both the charge and discharge duty cycles are sporadic. This work presents the application of a new methodology that enables diagnosis without the need for any maintenance cycle. It uses a 1-dimensiona...

In the past decade and half since their introduction, multiple frameworks of mechanistic models were made available to enable the quantification of loss of lithium inventory and loss of active materials. They usually come either with capacity/state of charge- or lithiation-based matching for the electrodes. While both approaches were believed to be...

Photovoltaics supply a growing share of power to the electric grid worldwide. To mitigate resource intermittency issues, these systems are increasingly being paired with electrochemical energy storage devices, e.g., Li-ion batteries, for which ensuring long and safe operation is critical. However, in this operation framework, secondary Li-ion batte...

Digital twins are cyber-physical systems that fuse real-time sensor data with models to make accurate, asset-specific predictions and optimal decisions. For batteries, this concept has been applied across length scales, from materials to systems. However, a holistic approach with a strong conceptual and mathematical framework is needed for battery...

Photovoltaic systems are providing a growing share of power to the electric grid worldwide. As more and more of these systems are tied with battery energy storage to balance their intermittency, being able to ensure long and safe operation of these batteries will become critical. Because of their sporadic usage, far from the typical constant curren...

While relatively young, the mechanistic modeling approach has proven extremely versatile and effective for Lithium-ion battery diagnosis and prognosis and it has gained tremendous traction in the past decade. The approach is relying on digital twins built from different matchings of the individual voltage response of each electrode. The digital twi...

This publication will present best practices for incremental capacity analysis, a technique whose popularity is growing year by year because of its ability to identify battery degradation modes for diagnosis and prognosis. While not complicated in principles, the analysis can often feel overwhelming for newcomers because of contradictory informatio...

Batteries are central to modern society. They are no longer just a convenience but a critical enabler of the transition to a resilient, low-carbon economy. Battery development capabilities are provided by communities spanning materials discovery, battery chemistry and electrochemistry, cell and pack design, scale-up, manufacturing, and deployments....

Lithium-ion batteries are ubiquitous in modern society with a presence in storage systems, electric cars, portable electronics, and many more applications. Consequently, to enable safe and reliable use of LIB systems, diagnosis and prognosis have become critical. Within the field of Artificial Intelligence, Deep Learning algorithms have achieved si...

Photovoltaic systems are providing a growing share of power to the electric grid worldwide. To mitigate resource intermittency issues, new systems are increasingly being paired with battery energy storage for which ensuring long and safe operation is critical. Unlike more typical battery applications, these batteries will undergo sporadic usage whi...

Novel non-destructive analyses open up possibilities to delve into degradation mechanisms of Lithium-ion batteries and diagnose internal states without the inconvenience of post-mortem characterizations. Low-rate constant current charge or discharge measurements (pOCV(Q)) lower than C/20 give comprehensive information on the electrochemical reactio...

Though relatively young, the mechanistic modeling approach has gained tremendous traction in the past decade as it was proven to be extremely versatile and effective for lithium-ion battery diagnosis and prognosis. The approach is relies on assembling digital twins by matching the individual voltage response of each electrode. Changing the matching...

Lithium-ion batteries can last many years but sometimes exhibit rapid, nonlinear degradation that severely limits battery lifetime. Here, we review prior work on “knees” in lithium-ion battery aging trajectories. We first review definitions for knees and three classes of “internal state trajectories” (termed snowball, hidden, and threshold trajecto...

Lithium-ion batteries can last many years but sometimes exhibit rapid, nonlinear degradation that severely limits battery lifetime. In this work, we review prior work on "knees" in lithium-ion battery aging trajectories. We first review definitions for knees and three classes of "internal state trajectories" (termed snowball, hidden, and threshold...

Electrochemical energy storage is central to modern society -- from consumer electronics to electrified transportation and the power grid. It is no longer just a convenience but a critical enabler of the transition to a resilient, low-carbon economy. The large pluralistic battery research and development community serving these needs has evolved in...

Grid-tied energy storage will play a key role in the reduction of carbon emissions. Systems based on Li-ion batteries could be good candidates for the task, especially those using lithium titanate negative electrodes. In this work, we will present the study of seven years of usage of a lithium titanate-based battery energy storage system on an isol...

Battery degradation is a fundamental concern in battery research, with the biggest challenge being to maintain performance and safety upon usage. From the microstructure of the materials to the design of the cell connectors in modules and their assembly in packs, it is impossible to achieve perfect reproducibility. Small manufacturing or environmen...

Understanding systematic trends in degradation of Li-ion batteries through a broad range of operating conditions is critical to improving their performance. Over the course of the last few years, researchers at Sandia National Labs have been conducting a systematic study of battery cycling behavior. In this study, dozens of commercial NCA (LiNi x C...

Accurate lithium battery diagnosis and prognosis is critical to increase penetration of electric vehicles and grid-tied storage systems. Both diagnosis and prognosis are complex due to the intricate, nonlinear, and path-dependent nature of battery degradation. Data-driven models are anticipated to play a significant role in the behavioral predictio...

The Li-ion battery revolutionized energy storage with its high energy density coupled with impressive reversibility; however, negative electrode reactivity and low positive electrode conductivity facilitate unpredictable capacity fade and catastrophic failure (e.g., thermal runaway). The origin of these degradation modes often remains elusive, maki...

The development of data driven methods for Li-ion battery diagnosis and prognosis is a growing field of research for the battery community. A big limitation is usually the size of the training datasets which are typically not fully representative of the real usage of the cells. Synthetic da-tasets were proposed to circumvent this issue. This public...

Intentionally applied interelectrode thermal gradients (ITGs) accelerate capacity loss in 35°C cells, and the directionality of the thermal gradient dictates the responsible degradation mode. By simulating cell self-heating at various temperatures and C-rates, we identify 35°C and C/5 as a condition that does not typically exhibit lithium (Li) plat...

Accurate lithium battery diagnosis and prognosis are critical to increase penetration of electric vehicles and grid-tied storage systems. They are both complex due to the intricate, nonlinear, and path-dependent nature of battery degradation. Data-driven models are anticipated to play a significant role in the behavioral prediction of dynamical sys...

Repurposing retired electric vehicle lithium ion batteries into stationary electricity grid storage will increase their utilization and correspondingly reduce their environmental footprint prior to recycling. In this work, we investigated the performance characteristics of leading commercial cell types repurposed into electricity grid services. Two...

The usage of electric vehicle batteries to assist the main electric grid for the storage of energy provided by intermittent sources should become an essential tool to increase the penetration of green energies. However, this service induces additional usage on the cells and, therefore, could degrade them further. Since degradation is path-dependent...

Li-ion battery degradation and failure are most commonly attributed to SEI (solid electrolyte interphase) growth or metallic lithium plating. We have demonstrated the ability to induce metallic lithium plating after very few cycles (5-10) with a small inter-electrode thermal gradient, maintaining the cathode warmer than the anode, ¹ 36 and 34°C res...

Non-intrusive diagnosis and prognosis methods are increasingly adopted to track Li-ion batteries ageing without additional cost due to destructive processes for post-mortem analyses. To qualify and quantify internal degradation mechanisms of a cell, Incremental Capacity Analysis (ICA) and Differential Voltage Analysis (DVA) have proven themselves t...

Accurate lithium battery diagnosis and prognosis is critical to increase penetration of electric vehicles and grid-tied storage systems. Both diagnosis and prognosis are complex due to the intricate, nonlinear, and path-dependent nature of battery degradation. Data-driven models are anticipated to play a significant role in the behavioral predictio...

Battery Energy Storage Systems (BESSs) show promise to help renewable energy sources integration onto the grid. These systems are expected to last for a decade or more, but the actual battery degradation under different real-world conditions is still largely unknown. In this work we analyzed different types of usage for batteries similar to deploye...

As the number of battery energy storage systems increase, along with their grid applications, it has become imperative to better understand and predict battery cell degradation. Accurately forecasting their durability under different usage regimes has become a priority in determining the operational and commercial risks associated with BESS deploym...

The usage of electric vehicle batteries to assist the main electric grid for the storage of energy provided by intermittent sources should become an essential tool to increase the penetration of green energies. However, this service induces additional usage on the cells and, therefore, could degrade them further. Since degradation is path-dependent...

Accurate lithium battery diagnosis and prognosis is critical to increase penetration of electric vehicles and grid-tied storage systems. They are both complex due to the intricate, nonlinear, and path-dependent nature of battery degradation. Data-driven models are anticipated to play a significant role in the behavioral prediction of dynamical syst...

Due to their high energy density, lithium-ion batteries with blended silicon-graphite (Si-Gr) anodes and nickel-rich (NMC) cathodes have been regarded as one of the most promising technologies for next-generation consumer electronics and electric vehicles. However, there are still several technical challenges to overcome for successful wide-spread...

Studies pinpointed the limitation of power-related performance for Li-ion batteries to the microstructure of each electrode. 1, 2 This random arrangement of the active material (AM) and carbon filling particles bound by a polymer is typically characterized through physical values such as tortuosity, porosity and Mac Mullin Number. ³ There is noneth...

Battery Energy Storage Systems (BESSs) show promise to help renewable energy sources integration onto the grid. These systems are expected to last for a decade or more, but the actual battery degradation under different real-world conditions is still largely unknown. In this work we analyzed different types of usage for batteries similar to deploye...

Today energy conversion devices typically rely on composite electrodes made of several materials interacting with one another. Understanding their individual and combined impacts on performance is essential in the pursuit of optimized systems. Unfortunately, this investigation is often disregarded in favor of quick publishable results. Here, Design...

Validation is an integral part of any study dealing with modeling or development of new control algorithms for lithium ion batteries. Without proper validation, the impact of a study could be drastically reduced. In a perfect world, validation should involve testing in deployed systems, but it is often unpractical and costly. As a result, validatio...

In this paper, we will describe in detail the setting up of a Design of Experiments (DoE) applied to the formulation of electrodes for Li-ion batteries. We will show that, with software guidance, Designs of Experiments are simple yet extremely useful statistical tools to set up and embrace. An Optimal Combined Design was used to identify influentia...

The ongoing extension of usage for lithium-ion cells and packs in both stationary and mobile applications necessitates a steeply increasing need for comprehensive tools and models to diagnose and prognose cell performance. Among those, a simple mechanistic framework using electrode half-cell data has gained a lot of attention due to its ability to...

State of health is an essential parameter for the proper function of large battery packs. A wide array of methodologies has been proposed in the literature to track state of health, but they often lack the proper validation needed to be universally adaptable to large deployed systems. This is likely induced by the lack of knowledge bridge between s...

Automobile dependency and the inexorable proliferation of electric vehicles (EV) compels accurate predictions of cycle life across multiple usage conditions and for multiple lithium-ion battery systems. Synthetic driving cycles have been essential in accumulating data on EV battery lifetimes. However, since battery deterioration is path-dependent,...

With the deployment of more and more large batteries on the grid addressing different applications, it is essential to better understand their degradation pattern and to accurately forecast their durability. In this work, the electrochemical data from a laboratory testing experiment replicating real usage was extensively investigated using incremen...

Cell-to-cell variations can drastically affect the performance and the reliability of battery packs. This study provides a model-based systematic analysis of the impact of intrinsic cell-to-cell variations induced by differences in initial state of charge, state of health, capacity ration, resistance and rate capability. The impact of these cell-to...

Lithium-ion cells currently power almost all electronic devices and power tools; they are a key enabling technology for electric vehicles and are increasingly considered to be the technology of choice for grid storage. In line with this increased applicability, there is also an increase in the development of new commercial lithium-ion cell technolo...

Automobile dependency and the inexorable proliferation of electric vehicles (EVs) compels accurate predictions of cycle life across multiple usage conditions and for multiple lithium-ion battery systems. Synthetic driving cycles have been essential in accumulating data on EV battery lifetimes. However, since battery deterioration is path-dependent,...

The research in the field of Li-ion batteries is stronger than ever, with a common aim of increasing the energy and power density. More and more studies pinpoint the limitation of power-related performance for Li-ion batteries to the microstructure of each electrode. This random arrangement of the active material and carbon filling particles bound...

Battery pack modeling is essential to improve the understanding of large battery energy storage systems, whether for transportation or grid storage. It is an extremely complex task as packs could be composed of thousands of cells that are not identical and will not degrade homogeneously. This paper presents a new approach toward battery pack modeli...

Battery degradation is extremely sensitive to usage and chemistry. Some batteries may be markedly sensitive to temperature, to state of charge, to both, or to some other factors. This raises concerns over battery durability in the rollout of electric vehicles (EVs) in hot climate. Additionally, with the integration of more and more intermittent ren...

Battery Energy Storage Systems (BESSs) can facilitate renewable energy sources integration onto the grid. For this application, these systems are expected to last for a decade or more, but the actual battery degradation under different real-world conditions is still largely unknown. In this work, three years of lithium titanate BESS usage in Hawai'...

Battery energy storage systems (BESS) are often viewed as solution to mitigate the intermittency of renewable energies in electric grids. However, battery degradation associated with grid-tied BESS usage has never been investigated in detail. This work was aimed at understanding the impact of a BESS representative usage profile on the degradation o...

Advances in lithium ion battery pack technology have led to significant market penetration for electric vehicles (EVs), but there is still a need to develop new battery technologies, better control algorithms, and faster charging strategies to enhance further the ownership experience. Once developed, these advances must be validated. Unfortunately,...

Battery Energy Storage Systems (BESSs) can facilitate renewable energy sources integration onto the grid. For this application, these systems are expected to last for a decade or more, but the actual battery degradation under different real-world conditions is still largely unknown. In this work, three years of lithium titanate BESS usage in Hawai'...

In the past twenty years, intensive experimental and modeling efforts have been carried out to access and predict the life expectancy of lithium-ion (Li-ion) batteries under calendar aging conditions. Aging studies are time intensive and usually only focus on one or two chemistries and a few aging conditions. They are therefore not providing a comp...

The use of lithium batteries for power and energy-hungry applications has risen drastically in recent years. For such applications, it is necessary to connect the batteries in large assemblies of cells in series and parallel. With a large number of cells operating together, it is necessary to understand their intrinsic variabilities, not only at th...

The utility of a single-point impedance-based technique to monitor the state-of-health of a pack of four 18650 lithium-ion cells wired in series (4S) was demonstrated in a previous publication. This work broadens the applicability of the single-point monitoring technique to identify temperature induced faults within 4S packs at 0 °C by two distinct...