Thermal runaway is a critical safety concern in lithium-ion battery systems, emphasising the necessity to comprehend its behaviour in various modular setups. This research compares thermal runaway propagation in different modular configurations of lithium-ion batteries by analysing parameters such as cell spacing and distribution, application of phase change materials (PCMs), and implementing insulating materials. The study at the module level includes experimental validation and employs a comprehensive model considering heat transfer due to electrical performance and thermal runaway phenomena. It aims to identify the most effective modular configuration for mitigating thermal runaway risks and enhancing battery safety. The findings provide valuable insights into the design and operation of modular lithium-ion battery systems, guiding engineers and researchers in implementing best practices to improve safety and performance across various applications.
Internal combustion engine (IC engine) vehicles are commonly used for transportation due to their versatility. Due to this, efficiency in design process of IC engines is critical for the industry. To assess performance capabilities of an IC engine, thermal predictions are of utmost consequence. This study describes a computational method based on unsteady Reynolds-averaged Navier–Stokes equations that resolves the gas–liquid interface to examine the unsteady single phase/multiphase flow and heat transfer in a 4-cylinder Inline (i-4) engine. The study considers all important parts of the engine i.e., pistons, cylinder liners, head, block etc. The study highlights the ease of capturing complex and intricate flow paths with a robust mesh generation tool in combination with a robust high-fidelity interface capturing VOF scheme to resolve the gas-liquid interfaces.
In recent years, the electrification of commercial vehicles has emerged as a prominent and transformative trend within the industry. In contrast to their passenger car counterparts, commercial vehicles present distinctive challenges, necessitating solutions that address higher peak and continuous torque demands, unique packaging and interface prerequisites, and extended service life expectations. BorgWarner has committed to research and development aimed at tackling these multifaceted challenges. As a result of these efforts, BorgWarner has successfully engineered an innovative and well-balanced solution tailored specifically to the electrification of commercial vehicles. This paper describes the transformation of a Ford F-550 into a full-fledged electric vehicle employing an 800V electrical system architecture.
The growing global adoption of electric vehicles (EVs) emphasizes the pressing need for a comprehensive understanding of thermal runaway in lithium-ion batteries. Prevention of the onset of thermal runaway and its subsequent propagation throughout the entire battery pack is one of the pressing challenges of lithium-ion batteries. In addition to generating excess heat, thermal runaway of batteries also releases hazardous flammable gases, posing risks of external combustion and fires. Most existing thermal runaway models in literature primarily focus on predicting heat release or the total amount of vent gas. In this study, we present a model capable of predicting both heat release and the transient composition of emitted gases, including CO, H2, CO2, and hydrocarbons, during thermal runaway events. We calibrated the model using experimental data obtained from an 18650 cell from the literature, ensuring the accuracy of reaction parameters.
The transition towards electrification in commercial vehicles is getting more attention in recent years. This technical paper details the conversion of a production medium duty class-5 commercial truck, originally equipped with a gasoline engine and 10-speed automatic transmission, into a battery electric vehicle (BEV). The conversion process involved the removal of the internal combustion engine, transmission, and differential unit, followed by the integration of an ePropulsion system housing a newly developed dual-motor eBeam axle that propels the rear wheels. Complementary additions encompass components such as an 800V/99 kWh battery pack, advanced SiC inverters, an 800V HVAC system, and a DC fast charging system. Central to this study is the control system governing the converted vehicle, prioritizing drivability, NVH suppression, and energy optimization. Evident improvements in responsiveness and reduced noise emission underscore the efficacy of the BEV's design.
Prevailing automotive development focus shifts towards passenger-centric development of vehicle systems. Comparative to autonomous driving development, the challenge evolves to describe all relevant driving situations with the necessary information and context to be able to develop and optimize vehicle systems to actual driving situations. The situational description or scenario, i.e., context or ambience in which a vehicle is located, represents a fundamental factor in consideration of system behavior and respective system optimization opportunities. The challenge to solve the respective automotive engineering problems for nonlinear multidimensional parameter spaces or mixed integer classification problems is to describe and limit the possible solution space by suitable methodologies. Conventional methods prove inadequate solution as they can only be applied with significant financial resources and engineering time efforts, as known by autonomous driving system development.
Battery electric vehicles (BEVs) are a solution to achieving sustainability and carbon neutrality. However, BEV performances are affected by the thermal performance imbalance in the battery packs under driving cycles. Temperature changes in the module, brick, and pack under the transient cycles must be understood for model-based development. The authors conducted chassis dynamometer experiments on a fully electric small crossover sports utility vehicle (SUV) to address this challenge, examining various conditions. The testbed employed a hub-type chassis dynamometer equipped with four dynamometers, a wind blower replicating actual ambient air, and a driving aid to assist the driver according to the Worldwide Harmonized Light Vehicles Test Cycle (WLTC) and Federal Test Procedures (FTP) under various ambient temperatures. The mid-size BEV with dual-motor featured 80 thermocouples mounted on the 74-kWh battery pack, including the cells, upper tray, side cover, and pack cover.
Lithium-ion batteries have become integral to many consumer electronics, electric vehicles, and renewable energy storage systems. Despite their widespread adoption, concerns related to thermal management persist, primarily due to the heat generated during their operation. The heat generated during lithium-ion battery operation adversely affects its performance, efficiency, safety, and lifetime. Hence, the thermal characterization of lithium-ion batteries is important for both the optimization of the battery cells and the design of the thermal management system for battery packs. This study presents an experimental investigation of heat generation of Li-ion batteries under different operating conditions, including charge-discharge rates, ambient temperatures, and states of charge. The experiments were conducted using a custom-designed multifunctional calorimeter, enabling precise measurement of the heat generation rate of the battery.
Model-based development (MBD), which makes it possible to study and adjust contradictory requirements between large number of functions and systems to a high level in a short period of time was implemented within an engine development. However, in fact, elevating engine systems to more advanced levels are a challenge even by satisfying the stand-alone requirements of components. In addition, a still higher level of technology is required for the conflicting relationships between multiple functions, e.g., the power output of an engine and its strength and durability performance, and the reconciliation between the numerous related systems that comprise it. Such reconciling technology requires the consideration of overall optimization that envisions design over a wide range. For present-day development, this would require an extensive period of examination over several years. This presents the issue of requiring an extended period for verification.
Opposed piston two-stroke (OP2S) diesel engines have demonstrated a reduction in engine-out emissions and increased efficiency compared to conventional four-stroke diesel engines. Due to the higher thermal efficiency and absence of a cylinder head, the heat transfer loss to the coolant is lower near the ‘Top Dead Center’. The selection and design of the airpath are pivotal in realizing the benefits of the OP2S engine architecture. Like any two-stroke diesel engine, the scavenging process and the composition of the internal residuals are predominantly governed by the pressure differential between the intake and the exhaust ports. Moreover, a significant portion of the work involved in pumping air is carried out externally to the engine cylinder which needs to be accounted for when calculating brake efficiencies.
With the increasing demand for Battery Electric Vehicles (BEVs) capable of extended mileage, optimizing their efficiency has become paramount for manufacturers. However, the challenge lies in balancing the need for climate control within the cabin and precise thermal regulation of the battery, which can significantly reduce a vehicle's driving range, often leading to energy consumption exceeding 50% under severe weather conditions. To address these critical concerns, this study embarks on a comprehensive exploration of the impact of weather conditions on energy consumption and range for the 2019 Nissan Leaf Plus. The primary objective of this research is to enhance the understanding of thermal management for BEVs by introducing a sophisticated thermal management system model, along with detailed thermal models for both the battery and the cabin.
The thermal strategy of the hybrid system is based on the battery cooling control, the motor, inverter cooling control and the evaporator cooling control. The water temperature sensor in this system of the electric drive circuit is arranged at the outlet of the radiator, without the water temperature sensor. Therefore, when calculating the air volume demand of the radiator and the water demand of the sub components of the electric drive circuit, it is necessary to estimate the inlet water temperature. The water temperature estimate is based on the heat transfer formula, which converts the heat release of the sub components of the circuit into the contribution to the temperature rise of the circuit plus the outlet temperature of the radiator of the last round to obtain the inlet water temperature. The heat transfer power of the inverter depends on the voltage and current. By adjusting the motor torque, the current is rapidly changed.
A two-particle lumped parameter model was developed for the chiller, and an experimental device was built to measure flow and heat exchange of the chiller. Empirical correlations for the convective heat transfer coefficients on both the coolant and refrigerant sides were obtained by fitting the experimental data. The influence of herringbone corrugated plate parameters, including angle, pitch, and depth, on performance of chillers at different Reynolds numbers (Re) was investigated. In modeling of a chiller two-phase and overheated zones of the refrigerant are considered simultaneously, and their respective areas were calculated to enhance the accuracy of the model. Using the Wilson plot method in experimental design, the convective thermal resistance of heat transfer on both sides was separated from the total thermal resistance to determine the actual coefficient of convective heat transfer.
The need for even more efficient internal combustion engines in the road transportation sector is a mandatory step to reduce the related CO2 emissions. In particular, this sector is presently responsible of about 12% of the greenhouse gases worldwide, and the path toward hybrid and electric powertrains has just begun. In particular, in heavy-duty vehicles the full electrification of the powertrain is far to be imagined. So, internal combustion engines will still play a significant role in the near/medium future. Hence, technologies having a low costs to benefits ratio will be favorably introduced in existing engines to reduce emissions. The thermal management of engines is today a recognized area of research. Inside this area, the interest toward the lubricant oil has a great potential but not yet fully exploited. Engine oil is responsible of the mechanical efficiency of the engine and has a significant potential of improvement.
Hydrogen Internal Combustion Engines (H2 ICE) are gaining recognition as a nearly emission-free alternative to traditional ICE engines. However, H2 ICE systems face challenges related to thermal management, N2O emissions, and reduced SCR efficiency in high humidity conditions (15% H2O). This study assesses how hydrogen in the exhaust affects after-treatment system components for H2 ICE engines, such as SCR, HOC, and ASC. A series of Steady-state experiments with inlet H2 concentrations of 0.25% to 1% and gas stream moisture levels up to 15% H2O were conducted to characterize the catalyst response to H2 ICE exhaust. The data was used to calibrate and validate system component models, forming the basis for a system simulation. System model validation involved comparing the model against real-world data from production diesel engine after-treatment systems for transient cycles, including Federal Test Procedure (FTP), low-load cycle (LLC), and Ramp model cycle (RMC) data.
The inverter of the Electrical Driven Compressor (EDC) is subjected to high thermal loads which are resulting from external temperature exposure and from compressor solicitations from the vehicle thermal loop (refrigerant nature, flow rate, compression rate, initial temperature). An incorrect thermal management of the inverter might lead to a significant decrease of efficiency which degrades the performance of the product, huge decrease in the product lifetime (electronics components failure) and even worse, might lead to a Hazardous Thermal Event. The need of the Automotive market to drastically decrease project development time, requires decreasing design and simulation activities lead time without degrading the design robustness, which is one additional complexity and challenge for the R&D team.
Ambient temperature is a very critical and sensitive use condition for electric vehicles (EVs), so it is imperative to ensure the maintenance of suitable temperatures during both usage and parking. This is particularly important in regions characterized by prolonged exposure to unfavorable temperature conditions. In such cases, it becomes necessary to implement insulation measures within parking facilities and allocate energy resources to sustain a desired temperature level. However, the availability of non-renewable energy sources is finite, necessitating further research to promote the sustainable and efficient utilization of energy. Consequently, the provision of affordable energy with minimal emissions assumes significant importance. Solar energy is a renewable and environmentally friendly source of energy that is widely available. However, the effectiveness of utilizing solar energy is influenced by various factors, such as the time of day and weather conditions.