The column materials were prepared by Denis BOROVITSKY, Alexey VOROBYEV-OBUKHOV, Mikhail GZOVSKIY
"SPIRAL" … UNDER THE HOOD
The angrily buzzing starter gives way to systems of almost instant start-up, capable of spinning the engine shaft up to 800 rpm in a tenth of a second. But where to get the strength for such a jerk?
The advent of combined starter-generator systems (Dinastart, ISAD and others) encouraged developers to revise the battery scale. Now the capacity does not come to the first place (the motor should start up in the first second), but the maximum discharge current. Therefore, the internal resistance should quickly tend to zero, which is possible only with an increase in the active area of the electrodes and a decrease in the distance between them. We have already introduced readers to the batteries of Optima (ZR, 1998, No. 10), which managed to roll the plates into a tube. The next step was made by the American Johnson Controls, who managed to turn them into the thinnest metal film. As a result, the total area of the electrode coiled into a spiral increased by 20 times, and the current path from plus to minus decreased by 20–100 times! A small lead-acid battery with a capacity of 6.5 A. h can give the “starter” a current of up to … 4900 A in the first 0.1 s. At the same time, a box measuring 117x196x105 mm and weighing 4.1 kg can be placed in any convenient place in the car upside down. It is noteworthy that the ambient temperature can be in the range from –60 to + 100 ° С during a discharge and from –20 to + 75 ° С during a charge.