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800-volt systems make sense only in certain electric cars, according to Lexus

Toyota, and therefore Lexus, had remained in a kind of background when betting on the electric car. Until very recently, all its energy was put into hybrid cars, but the arrival of its first electric cars has been quite a blow to the table. The next step is the 800 volt electrical systemsbut Toyota and Lexus do not see it as the best solution for all their electrics.

The 800-volt architecture in electric cars has several advantages. On a practical level, the most important is that it allows recharging with more power in direct current, which means reducing waiting times for the customer when they have to charge the battery. Implementing this technology in cars with a relatively small battery would allow for very short recharging times.

On the other hand, the higher voltage also increases the efficiency of the system. Working with 800 volts generates less heat loss in the cables, and allows thinner cables to be used throughout the vehicle’s propulsion system (battery, motor, etc.), which in turn saves weight, space and manufacturing costs. A priori, everything seems to be advantages, but at Lexus they believe that it is only practical in certain types of vehicles.

In a recent interviewTakashi Watanabe, chief engineer at Lexus, confirmed that the company already has an 800-volt electrical architecture ready. However, the first electric Lexus model will not have it (neither will its cousin, the Toyota bZ4X). The reason, according to Watanabe, is the relationship between battery capacity and charge. According to Watanabe, the use of an 800-volt electrical architecture for faster charging is justified with larger batteries, starting at “around 100 kWh” in capacity. With batteries of that capacity, the need for higher charging powers to reduce standby times increases, and that’s where the 800 volts will come into play.

Lexus-RZ-450e-2023-02
The Lexus RZ 450e has a 71.4 kWh battery that works with a nominal voltage of 355 V.

For that reason, Toyota and Lexus will study “case by case”, model by model, the use of 800-volt systems. The 800-volt systems would therefore be reserved for the models at the top of the range, the largest and with a battery above 100 kWh. In the Lexus RZ 450e, whose battery has a capacity of 71.4 kWh, a “conventional” system that works at 400 volts will be used. Fast charging supports a maximum of 150 kW of DC power, which allows you to charge from 0 to 80% in 30 minutes.

At the moment there are few models on the market that use an 800-volt electrical system: Audi e-tron GT, Hyundai IONIQ 5, Kia EV6 and Porsche Taycan. The Lucid Air goes one step further with a 900-volt system, the only one in the world today.

Watanabe also pointed out that higher charging power (above 150 kW) means higher costs both by the hardware of the vehicle as well as by the recharging infrastructure.

An infrastructure that is developing at different rates depending on the region. Watanabe pointed out that the specific needs of each region will dictate much of what the manufacturer does in relation to the performance of its cars. For example, in the United States, most fast chargers offer 150 kW of maximum power, while the deployment of super fast charging (350 kW) is being slow. There are also differences in the needs or tastes of the clientele: while the US market considers a range of around 350 kilometers scarce, in markets such as China it is considered more than sufficient.

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