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Despite the fact that methanol is toxic to human health and causes serious damage to automobile engines and fuel system components, methanol-containing gasoline is becoming popular in some areas. Methanol demonstrates similar chemical properties to ethanol (which is already established as an additive to gasoline), so that it is difficult to identify methanol-containing gasoline without performing proper chemical analysis. In this study, we report a low-cost, portable, and easy-to-operate sensor that selectively changes color in response to methanol contained in gasoline. The colorimetric sensor will be useful for automobile users to avoid methanol-containing gasoline upon refueling.

All-solid-state lithium (Li)-ion batteries have attracted significant interest for their enhanced energy density compared with conventional batteries employing an organic liquid electrolyte. However, the interfacial impedance and reaction between electrodes and the electrolyte can hinder the transport of Li-ions, thus degrading the battery performance. This paper presents a systematic screening method to identify coatings to reduce impedance and maintain interface stability during battery operation. Promising coating materials are rapidly selected by evaluating properties for ideal coating materials from computational databases containing a vast collection of Li compounds. Finally, a few candidates are discovered and their battery performances are tested. This approach is demonstrated to be an efficient way to predict and evaluate functional coatings for a high performance all-solid -state battery design.

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.

In 2022, Toyota launched new battery electric vehicle (BEV), the Toyota bZ4X. Unlike gasoline-powered vehicles, BEVs require charging. Users want increased range and shorter charging times. bZ4X's charging system increased range and shortened AC/DC charging time compared to the Lexus UX300e launched in 2020. A new unit called Electricity Supply Unit (ESU) was developed that integrated a DCDC converter, on-board charger, DC relays, and a branch box for power distribution function into a single unit. The design moved the branch box out of the battery pack to make room for the battery capacity, and it integrated the power conversion function into a single unit, making it more compact than if each unit were mounted separately. A 7 kW or 11 kW on-board charger is included with the vehicle. The 7 kW on-board charger is inside ESU; the 11 kW charger is external to the ESU.

Recently, automakers have launched various types of electric vehicles (EVs) to help reduce global CO₂ emissions and reduce dependency on fossil fuel energy. Because the lithium-ion batteries that are currently under development are restricted by energy density, the physical size and mass of the battery must be significantly increased to extend the cruising range of the EV. Furthermore, dedicated charging infrastructure is required to charge the battery in a short time. At SAE in 2012, Toyota Motor Corporation proposed a concept that described the EV as suitable mainly for short-distance transportation now and in the near future. Later in the same year, Toyota launched a new EV that embodies this concept in the American and Japanese markets. This new EV is light-weight and has a compact body size, and its battery capacity is designed to sufficiently cover distances traveled in daily life. Charging is assumed to take place mainly at home.

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.

This paper describes the high-pressure hydrogen storage system developed for new FCV. With the aim of further popularizing FCVs, this development succeeded in improving the performance of the system and reducing costs. This new storage system consists of multiple tanks of different sizes, which were optimized to store the necessary amount of hydrogen without sacrificing the interior space of the vehicle. The new tanks achieved one of the highest volume efficiencies in the world by adopting high-strength carbon fiber, developed in conjunction with the carbon fiber manufacturer, and by optimizing the layered construction design which allowed the amount of carbon fiber to be reduced. To increase the amount of available hydrogen, the longer high pressure tanks were mounted under the vehicle floor unlike the previous model. This was accomplished by the following two measures: First, individual design and manufacturing measures for the tanks were adopted.

We developed a high performance automotive lithium-ion battery and applied it to our new Toyota Intelligent Idling Stop System. This hybrid power management system has been introduced in the “intelligent package” of Toyota Vitz vehicles sold in Japan. The lithium-ion battery is installed under the seat on the passenger-side. The battery supplies electric power to the auxiliary electrical systems during the “idling stop” mode, and when restarting the engine. The main requirements of this battery are to supply high electric power output even at low temperatures and at the same time, maintain continuous power during charge and discharge cycling, and have long storage life. This performance has been accomplished successfully through a series of improvements in battery materials and structures.

Lexus launched the new hybrid luxury coupe LC500h in 2017 to help enhance its brand image and competitiveness for the new generation of Lexus. During the development of the LC500h, major improvements were made to the hybrid system by adopting the newly-developed Multi Stage Hybrid System, which combines a multi stage shift device with the transmission from the previous hybrid system to maximize the potential of the electrically-controlled continuously variable transmission. Optimum engine and electrical component specifications were designed for the new vehicle and transmission. As a result, the LC500h achieves a 0-to-60 mph acceleration time of 4.7 seconds, with a combined fuel economy of 30.0 mpg while satisfying SULEV emissions requirements. Two controls were constructed to help resolve the issues that arose due to adding the shift device.

Reducing vehicle CO2 emissions is an important measure to help address global warming. To reduce CO2 emissions on a global basis, Toyota Motor Corporation is taking a multi-pathway approach that involves the introduction of the optimal powertrains according to the circumstances of each region, including hybrid electric (HEVs) and plug-in hybrid electric vehicles (PHEVs), as well as battery electric vehicles (BEVs). This report describes the development of a new PHEV system for the Toyota Prius. This system features a traction battery pack structure, transaxle, and power control unit (PCU) with boost converter, which were newly developed based on the 2.0-liter HEV system. As a result, the battery capacity was increased by 1.5 times compared to the previous model with almost the same battery pack size. Transmission efficiency was also improved, extending the distance that the Prius can be driven as an EV by 70%.

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.

In recent years, many various energy sources have been investigated as replacements for traditional automotive fossil fuels to help reduce CO₂ emissions, respond to instabilities in the supply of fossil fuels, and reduce emissions of air pollutants in urban areas. Toyota Motor Corporation considers the plug-in hybrid vehicle, which can use electricity efficiently, to be the most practical current solution to these issues. For this reason, Toyota began sales of the Prius plug-in hybrid in early 2012 in both the U.S. and Japan. This is the first plug-in hybrid vehicle to be mass-produced by Toyota Motor Corporation. Prior to this, in December 2009, Toyota sold 650 plug-in hybrid vehicles through lease programs for verification testing in the U.S., Europe, and Japan. The system of the recently launched mass-produced vehicle underwent major improvements in response to the results of this verification testing. As a result, EV range was increased with a smaller battery.

Toyota has launched a new BEV which incorporates our newest evolutions in BEV powertrain systems and vehicle platform innovations. The new BEV uses newly developed large format battery cells, which, in addition to achieving our key performance and safety targets, also incorporates new technologies resulting in improved battery energy density and a reduction in battery deterioration. For the BEV battery cooling, to enhance safety, the cooling plate and the battery cells are separated by a chamber structure. The battery pack also incorporates a newly developed high resistance coolant with low conductivity. The new BEV improves system efficiency by leveraging some technologies that were originally developed for HEV and developing new systems. For example, radiant heating and a newly developed heat pump system improve EV driving range. This presentation will introduce our new battery technologies and discuss our new BEV system.

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.

Cold weather operation has been a major issue for fuel cell hybrid vehicles (FCHV). To counteract the effects of low temperatures on FCHV 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 order to suppress increases in exhaust hydrogen concentration due to pumping hydrogen during rapid warm-up, dilution control using bypass air and reduction of concentration overvoltage by a minimum voltage guard were implemented. These approaches effectively control waste heat generation and suppress exhaust hydrogen concentrations during cold start and warm-up. These developments were incorporated into the 2008 Toyota FCHV-adv and it was confirmed that the rapid warm-up operation strategy allowed the FCHV-adv to be successfully and repeatedly started at -30°C.

Toyota has been introducing several hybrid vehicles (HV) as a countermeasure to concerns related to the automotive mobility like CO2 reduction, energy security, and emission reduction in urban areas. A next step towards an even more effective solution for these concerns is a plug-in hybrid vehicle (PHV). This vehicle combines the advantages of electric vehicles (EV), which can use clean electric energy, and HV with it's high environmental potential and user-friendliness comparable to conventional vehicles such as a long cruising range. This paper describes a newly developed plug-in hybrid system and its vehicle performance. This system uses a Li-ion battery with high energy density and has an EV-range within usual trip length without sacrificing cabin space. The vehicle achieves a CO2 emission of 59g/km and meets the most stringent emission regulations in the world. The new PHV is a forerunner of the large-scale mass production PHV which will be introduced in two years.

Toyota has been developing various environmentally friendly vehicles to address global environmental concerns. In 1996, Toyota started to sell the battery powered "RAV4" electric vehicle, and introduced the "e-com" in 1997. Late last year, Toyota launched production of the world's first hybrid vehicle, the "PRIUS", doubling the fuel efficiency and drastically reducing the emission of carbon dioxide. Toyota is also conducting research in the area of fuel cell electric vehicles. This paper explains the electric systems of these vehicles, i.e., motor, inverter, Ni-MH battery and control. Some of the technical problems will also be discussed

This paper describes the development of a new e-AWD hybrid system developed for SUVs. This hybrid system consists of a high-torque 2.4-liter turbocharged engine and a front unit that contains a 6-speed automatic transmission, an electric motor, and an inverter. It also includes a rear eAxle unit that contains a water-cooled high-power motor, an inverter, and a reduction gear, as well as a bipolar nickel-metal hydride battery. By combining a turbo engine that can output high torque across a wide range of engine rpm with two electric motors (front and rear), this system achieves both smooth acceleration with a torquey driving feeling and rapid response when the accelerator pedal is pressed. In addition, new AWD control using the water-cooled rear motor realized more stable cornering performance than the previous e-AWD system.

For energy saving and global warming prevention, Toyota has developed Toyota Hybrid System (THS) for mass-produced passenger cars, which achieves drastic improvement in fuel efficiency and reduction in exhaust emissions compared to conventional gasoline engine cars. The THS has two motive power sources which engage depending on driving conditions. It's power is supplied either from an engine (controlled by the engine ECU) or an electric motor (controlled by the motor ECU) which is powered by a high-voltage battery (monitored by the battery ECU). These ECUs are controlled by a hybrid ECU. Each ECU has been developed with a fail-safe system in mind, to ensure driver safety in case of vehicle breakdowns. Among these ECUs, this paper reports particularly on the newly introduced ECUs: hybrid ECU and battery ECU. In the development of these ECUs, special attention was focused on fail-safe performance.

Toyota introduced the first generation Prius in 1997. The vehicle was conceived, designed and launched as a dedicated, mass-produced global hybrid vehicle platform, the first of its kind. The introduction of the 2nd and 3rd generation Prius (2003, 2009) saw vehicles with significantly improved performance, including fuel efficiency. The Prius Alpha (Japan/EU), launched in 2011, represented Toyota first foray with Li-ion battery in a strong hybrid configuration. For the Prius Alpha, the adoption of a compact Li-ion battery resulted in sufficient cabin space to allow a 3rd row of seats while maintaining high fuel efficiency. Before and after the launch of the Prius Alpha, an extensive list of tests was performed on the Li-ion battery pack, including electrical, electrochemical, mechanical, and safety. The evaluations were performed in the lab, in the field (demonstration fleets) and by acquiring vehicles used by customers.