A mobile phone that goes off without warning, or a car breakdown? Yes, it can be due to low temperatures. But why do the batteries discharge faster under these conditions?
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[EN VIDÉO] From Volta to Graphene: the evolution of batteries The most common type of battery is the lithium-ion battery. Several technologies are in the running to replace it.
There are two main elements to be aware of in a battery : them electrodes and the electrolyte. The electrodes are theanodeor negative pole, and the cathodeor positive pole, between which the electrons. The passage of electrons from one pole to the other provides theenergy necessary for the operation of a device, or its recharging — we will see in a moment that their direction of circulation is important.
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But, to circulate, the electrons need a medium in which to evolve. Thus, between the cathode and the anode, there is a liquid called “conductor” baptized electrolyte. The ions that make up this electrolyte are movement, and it is this mobility that generates current by circulating electrons. This set of electrodes and electrolyte forms what is called a cell which thus makes it possible to generate energy.
A battery is made up of thousands of cells working together. So when we use our cellphone for example, the electrical circuit is in a so-called “closed” state. This means that the anode loses electrons and the cathode will recover them. In other words, it is the phenomenon that makes it possible to create electricity enough for you to use your smartphone all day. Conversely, when charging batterythe chemical process that takes place is reversed: this time, the electrical circuit is open, and the electrons then leave in the opposite direction.
Batteries facing winter temperatures
All the chemical reactions which lead to the proper functioning of a battery are not necessarily suitable for climates extremes. At low temperatures, a battery will produce much less running. And for good reason, chemical reactions take place more slowly. The electrolyte loses its ability to conductivity. It is more viscous, and its voltage increases, so the movement of electrons, from one electrode to another, is more complicated, and therefore greatly slowed down. In this context, the energy consumed will mainly generate enough heat to simply operate the battery which therefore discharges much faster. It is for this reason that it is preferable to store your phone in an inside pocket in very cold weather.winter.
If this is not possible for you, know that there are also batteries, called “low temperatures”, which will withstand these conditions. These batteries work thanks to a modification made on one of the electrodes. The anode in the batteries of a lambda telephone is in graphitea material which tends to perform less well in winter. To deal with this problem, researchers have succeeded in developing a battery with a new anode in carbon said to be “non-graphitisable”. The principle remains the same, but this new material allows electron transfers below -40°C.
That said, this technology is valid for mobile phones but, for cars, it’s more complicated. For the moment, the parade found by certain countries experiencing episodes of extreme cold, would be to connect cars to electricity arrivals in car parks to keep the engine, oil and battery warm.
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