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In recent years, automakers have been developing various types of environmentally friendly vehicles such as hybrid (HV), plug-in hybrid (PHV), electric (EV), and fuel cell (FCV) vehicles to help reduce greenhouse gas (GHG) emissions. However, there are few commercial solar vehicles on the market. One of the reasons why automakers have not focused attention on this area is because the benefits of installing solar modules on vehicles under real conditions are unclear. There are two difficulties in measuring the benefits of installing solar modules on vehicles: (1) vehicles travel under various conditions of sunlight exposure and (2) sunlight exposure conditions differ in each region. To address these problems, an analysis was performed based on an internet survey of 5,000 people and publically available meteorological data from 48 observation stations in Japan.

Polymer electrolyte membrane fuel cell (PEFC) systems for fuel cell vehicles (FCVs) require both performance and durability. Carbon is the typical support material used for PEFC catalysts. However, hydrogen starvation at the anode causes high electrode potential states (e.g., 1.3 V with respect to the reversible hydrogen electrode) that result in severe carbon support corrosion. Serious damage to the carbon support due to hydrogen starvation can lead to irreversible performance loss in PEFC systems. To avoid such high electrode potentials, FCV PEFC systems often utilize cell voltage monitor systems (CVMs) that are expensive to use and install. Simplifying PEFC systems by removing these CVMs would help reduce costs, which is a vital part of popularizing FCVs. However, one precondition for removing CVMs is the adoption of a durable support material to replace carbon.

In recent years, the realization of carbon neutrality has become an activity to be tackled worldwide, and automobile manufacturers are promoting electrification of power train by HEV, PHEV, BEV and FCEV. Although interest in BEV is currently growing, vehicles equipped with internal combustion engines (ICE) including HEV and PHEV will continue to be used in areas where conversion to BEV is not easy due to lack of sufficient infrastructures. For such vehicles, low-viscosity engine oil will be one of the most important means to contribute to further reduction of CO2 emissions. Since HEV requires less work from the engine, the engine oil temperature is lower than that of conventional engine vehicles. Therefore, the reduction of viscous resistance in the mid-to-low temperature range below 80°C is expected to contribute more to fuel economy. On the other hand, the viscosity must be kept above a certain level to ensure the performance of hydraulic devices in the high oil temperature range.

For over a decade and a half, Toyota Motor Corporation has been developing fuel cell vehicles (FCVs) and is continuing various approaches to enable mass production. This study used new methods to quantitatively observe some of the mass transfer phenomena in the reaction field, such as oxygen transport, water drainage, and electronic conductivity. The obtained results are applicable to the design requirements of ideal reaction fields, and have the potential to assist to reduce the size of the fuel cell.

Electrode catalyst (platinum) degradation represents a major challenge to the performance and durability of polymer electrolyte membrane fuel cells (PEMFCs) in Fuel Cell Vehicles (FCVs). While various mechanisms have been proposed and investigated previously, there is still a need to develop in situ imaging techniques that can characterize and provide direct evidence to confirm the degradation process. In the present study, we report an in situ transmission electron microscopy (TEM) method that enables real time, high-resolution observation of carbon-supported platinum nanoparticles in liquid electrolyte under working conditions. By improving the design of the Micro Electro Mechanical Systems (MEMS) sample holder, the migration and aggregation of neighboring platinum nanoparticles could be visualized consistently and correlated to applied electrode potentials during aging process (i.e., cyclic voltammetry cycles).

Multi-cylinder hydrogen-absorbing alloy tanks for fuel cell vehicles have 10 to 40 metallic cylinders that are bundled and filled with hydrogen-absorbing alloy. In this system, the cylinders themselves act as a heat exchanger and the working pressure is lowered to 10 to 20 MPa compared with high-pressure MH tanks. Moreover, both heat conduction and mass reduction can be achieved by reducing the wall thickness of the cylinders. A model verification experiment was conducted using a one-quarter-scale prototype of a full size tank, and a conduction simulation model verified in the experiment was used to predict the performance of the full size tank. Results showed that it is possible to fill the tank with hydrogen to 80% of its capacity in a five-minute filling time, although issues related to heat conductivity performance require improvement. Accordingly, it may be possible to adopt this tank as part of a system if the storage amount of the hydrogen-absorbing alloy can be increased.

While carbon supported PtCo alloy nanoparticles emerged recently as the new standard catalyst for oxygen reduction reaction in polymer membrane electrolyte fuel cells, further improvement of catalyst performance is still of great importance to its application in fuel cell vehicles. Herein, we report two examples of such efforts, related to the improvements of catalyst preparation and carbon support design, respectively. First, by lowering acid treatment voltage, the effectiveness for the removal of unalloyed Co was enhanced significantly, leading to less Co dissolution during cell operation and about 40% higher catalyst mass activity. It has been also found that the use of nonporous carbon support material promoted mass transfer and resulted in substantial drop of overpotential at high current and low humidity. This result may suggest an effective strategy towards the development of fuel cell systems that operate without additional humidification.

Toyota Motor Corporation (TMC) has been developing fuel cell (FC) system technology since 1992. In 2008 the Toyota "FCHV-adv" was released as part of a demonstration program. It established major improvements in key performance areas such as cold start/drive capability, efficiency, driving range, and durability. However, in order to facilitate the commercial widespread adoption of fuel cell vehicles (FCVs), improvements in performance and further reductions in size and cost were required.In December 2014, Toyota launched the world’s first commercially available fuel cell vehicle (FCV) the "Mirai" powered by the Toyota Fuel Cell System (TFCS). Simplicity, reliability and efficiency have been significantly improved within the Toyota TFCS. As a result, the Mirai has become an attractive vehicle which could lead the way towards full-scale popularization of FCVs.

To achieve carbon neutrality by reducing carbon dioxide (CO2) emissions, vehicles with an internal combustion engine have started to be replaced by electrification vehicles such as hybrid electric vehicles (HEVs), plug-in HEVs (PHEVs), and battery EVs (BEVs) worldwide, which have motors in their transaxles (T/As). Reducing transmission torque loss in the transaxles is effective to reduce CO2 emissions, and lowering the viscosity of lubrication fluids in T/As is a promising method for reducing churning and drag loss. However, lowering viscosity generally leads to thin oil films and makes the lubrication condition severe, resulting in worse anti-fatigue and anti-seizure performance. To deal with these issues, we made improvements on the additive formulation of fluid, such as the addition of an oil-film-forming polymer, chemical structure change of calcium detergents, and an increase of anti-wear additives including phosphorus and sulfur.

Weight reduction for a fuel cell vehicle (FCV) is important to contribute a long driving range. One approach to reduce vehicle weight involves using a carbon fiber reinforced plastic (CFRP) which has a high specific strength and stiffness. However, a conventional thermoset CFRP requires a long chemical reaction time and it is not easy to introduce into mass production vehicles. In this study, a new compression-moldable thermoplastic CFRP material for mass production body structural parts was developed and applied to the stack frame of the Toyota Mirai.

The new Toyota Mirai hydrogen fuel cell electric vehicle (FCEV) was launched in December 2020. Achieving a low-cost, high-performance FC stack is an important objective in FCEV development. At the same time, it is also necessary to ensure vehicle safety. This paper presents an overview of the safety requirements for onboard FC stacks. It also describes the simulation and evaluation methods for the following matters related to the FC stack. i) Impact force resistance: The FC stack was designed to prevent cell layer slippage due to impact. Constraint force between the cell layers is provided by the frictional force between the cells and an external constraint. A simulation of the behavior of the cell layers under impact force was developed. The impact force resistance was confirmed by an impact loading test. ii) Hydrogen safety: The FC stack was designed so that permeated hydrogen is ventilated and the hydrogen concentration is kept below the standard.

Toyota Motor Corporation began leasing a new generation fuel cell vehicle the FCHV (Fuel Cell Hybrid Vehicle) in December 2002. That vehicle includes a new variable voltage power electronics system and uses the Nickel Metal Hydride (Ni-MH) battery system from the Prius hybrid gasoline electric vehicle. This paper describes on-going efforts to model optimum secondary storage systems for future vehicles. Efficiency modeling is presented for the base Ni-MH storage system, an ultra capacitor system and a Lithium ion (Li-ion) battery system. The Li-ion system in combination with a new high efficiency converter shows a 4% improvement in fuel economy relative to the base system. The ultra capacitor system is not as efficient as the base system.

The world is currently facing environmental issues such as global warming, air pollution, and high energy demand. To mitigate these challenges, the electrification of vehicles is essential as it is effective for efficient fuel utilization and promotion of alternative fuels. The optimal approach for electrification varies across different markets, depending on local energy conditions and current circumstances. Consequently, Toyota has taken the initiative to offer a comprehensive lineup of battery electric vehicles (BEV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and fuel cell electric vehicles (FCEV), aiming to provide sustainable solutions tailored to the unique situations and needs of each region. As part of this effort, Toyota has developed the 5th generation of hybrid electric vehicles. This paper describes the electric motor used in the new Toyota Camry which achieves high torque, high power, low losses, and compact design.

The first MIRAI was launched in 2014 as the world’s first commercial fuel cell vehicle (FCV) [1]. Compared to the FC stack used in the first MIRAI, the FC stack in the new MIRAI achieved one of the highest volumetric power densities in the world (5.4 kW/L, excluding end plates, 1.5 times higher than the FC stack in the first MIRAI) by adopting a new flow channel for the bipolar plate and an improved electrode [2]. Enhancing the current density is an important means of increasing power performance and reducing size. The bipolar plate functions to distribute gas and drain water inside the cells to stabilize current generation. However, a conventional straight flow channel tends to cause flooding, which makes it difficult to maintain stable current generation. A partially narrow flow channel was developed to enhance oxygen diffusion without the 3D fine-mesh flow field that was adopted in the previous FC stack.

Toyota Motor Corporation (TMC) has been developing fuel cell vehicles (FCVs) since 1992. As part of a demonstration program, TMC launched the FCHV-adv in 2008, which established major technical improvements in key performance areas such as efficiency, driving range, durability, and operation in sub-zero conditions. However, to encourage commercialization and widespread adoption of FCVs, further improvements in performance were required. During sub-zero operating conditions, the FC system output power was lower than under normal operating conditions. The FC stack in the FCHV-adv needed to dry the electrolyte membrane to remove unneeded water from the stack. This increased the stack resistance and caused low output power. In December 2014, TMC launched the world’s first commercially available FCV named the Mirai, which greatly improved output power even after start-up in sub-zero conditions.

The fuel cell (FC) stack that was developed for a new FCV achieves a power density of 3.1 kW/L (one of the highest in the world) by the use of an innovative cell flow field structure, electrodes, and a simplified stack tightening structure. These innovations allow the FC stack to be installed under the floor of a sedan-type fuel cell vehicle (FCV). Underfloor installation also required excellent impact resistance, waterproofing, and rustproofing performance. These items were quantified and analyzed during the development of the FC stack, resulting in an optimized structure capable of enduring a wide range of possible underfloor inputs.

Various issues must be resolved before sustainable mobility can be achieved, the most important of which are reacting to energy supply and demand, and lowering CO2 emissions. At present, the fact that the vast majority of vehicles run on conventional oil is regarded as a problem for which Toyota Motor Corporation (TMC) is developing various technological solutions. Fuel cell (FC) technology is one of the most promising of these solutions. A fuel cell is an extremely clean device that uses hydrogen and oxygen to generate power without emitting substances like CO2, NOx, or PM during operation. Its energy efficiency is high and it is widely expected to form the basis of the next generation of powertrains. Since 1992, TMC has been working to develop the main components of fuel cell vehicles, including the fuel cell itself, and the high pressure hydrogen tank and hybrid systems.

Cold weather operation has been a major issue for fuel cell vehicles (FCV). In order to counteract this effect on FCV operation, an approach for rapid warm-up operation based on : concentration overvoltage increase and conversion efficiency decrease by limiting oxygen or hydrogen supply, was adopted in a running fuel cell hybrid vehicle. In order to adjust the output power response of the fuel cell to the target power of the vehicle, -the inherent capacitance characteristics of the fuel cell were measured- based on the oxidation-reduction reaction and an electric double-layer capacitor, and an equivalent electric circuit model of a fuel cell with the capacitance was constructed. This equivalent electric circuit model was used to develop a power control algorithm to manage absorption of the surplus power, or deviation, to the capacitance.

Toyota Motor Corporation (TMC) has been developing fuel cell (FC) technology since 1992, and finally “MIRAI” was launched in 15th Dec. 2014. An important step was achieved with the release of the “FCHV-adv” in 2008. It established major improvements in efficiency, driving range, durability, and cold start capability. However, enhancing performance and further reductions in size and cost are required to facilitate the commercial widespread adoption of fuel cell vehicles (FCVs). TMC met these challenges by developing the world's first FC stack without a humidifying system. This was achieved by the development of an innovative cell flow field structure and membrane electrode assembly (MEA), enabling a compact and high-performance FC stack. Other cost reduction measures incorporated by the FC stack include reducing the amount of platinum in the catalyst by two-thirds and adopting a carbon nano-coating for the separator surface treatment.

Since 1992, Toyota Motor Corporation (TMC) has been working on the development of fuel cell system technology. TMC is designing principal components in-house, including fuel cell stacks, high-pressure hydrogen storage tank systems, and hybrid systems. TMC developed the '02 model TOYOTA FCHV, the world-first market-ready fuel cell vehicle, and started limited lease of the vehicles in 2002. In 2005, TMC developed a new model of TOYOTA FCHV which obtained vehicle type certification in Japan, and is currently available for leasing. TMC has improved the cruising range and cold start/drive capability of the TOYOTA FCHV, and conducted public road tests to evaluate the performance. The improved TOYOTA FCHV successfully traveled from Osaka to Tokyo (approximately 560km, 350 miles) on a single fueling of hydrogen. In addition, the cold weather tests carried out in Hokkaido and North America have verified its starting/driving capability at subfreezing temperatures including -37°C.