At latest the second-generation Toyota Prius one has looked at more closely, despite slight warnings taken the covering from the rear luggage compartment. Of course, the electric system had already shut down. So continued and then the surprise: Together with the high-voltage battery appears a very ordinary 12 V lead battery, the raises questions of course.

Difficult it may be to examine all of today's hybrids, but the bet is, all have the comparatively heavy battery with conventional technology on board. Why, if it is more than enough electrical energy available and one otherwise already saves fractions of a kilogram.

One of possibly several reasons may be that classic lead-acid battery in the vehicle electrical system is indispensable because of their ability to take voltage peaks. These are the enemy of almost any electronics, occur when loose contact under electricity and switching on of high electrical loads, including even when start the vehicle using a second battery.

The previously known power relay helps little there, possibly even pours petrol on the fire. Right here would be present applications, e.g. for the pictured above electronically relay, called 'Q-diode'. At the large cross- sections, you may identify perhaps which loads it can switch. The manufacturer speaks of up to 400 amperes and mentioned other benefits also.

The switch and the relay are pretty much the last mechanical components in the electrical system, nevertheless still manifold existing. It is advantageous that they separate electric circuits galvanically. Electronic technician they dislike because they are in addition to the production of voltage peaks also more prone to wear and does not limit oneself to a single switching operation because of the so-called 'bounce'.

In the video below we can not look in completely. It is certain that not only one diode is inside. Overall, the unit has characteristics that were formerly exclusively attributed to the thyristors. How the switching operation is performed and which measured values are used for that, probably remains a company secret. 11/12