Requests : The battery

The era of purely mechanical machines is pretty much obsolete. Replacing it is a vast horde of electricity consuming devices. They control, find, optimize and do WAAAY more jobs than good ol’ mechanical contraptions. As for cars, electronics and mechanics simultaneously work together to give one a brilliant driving experience. As always though, the electronic and electrical systems need a power source that is sustainable, can get recharged on the go and is mass produced. What is it? It’s a wind turbine! Nah, just kidding. That is efficient, but it is for another time. The item in question is the battery.

(This post is in response to a request from a reader who goes by ‘janith’, so here you go!)

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The car battery is like any other battery but also unlike any other. The history of it dates back to the 1920’s, when cars with electric starters instead of cranks became popular. Why crank a rod to start a car instead of just twisting a key in an ignition slot? Also, early cars had very few electrical functions. For instance, horns were just bells, lamps were fuel – powered and only the engine used electricity. Then, the Hudson Motor car Company started to use standardized batteries designed and made by Battery International Council, which set the standards for car batteries in 1918.

In the early stages of cars with these batteries, their electrical functions ran on a charge of only 6 volts. Cars then had tiny engines, power and needed very little to get running until the 1950’s. These 6 volt systems had their positive lead connected directly to the chassis for engine startup and battery charging. This was called a positive ground system. Today’s vehicles use a negative ground system, where the negative lead is attached to the chassis. After the 1950’s, that system got upgraded to a 12 volt setup, due to the fact that cars started having bigger engines, more electric features and electronics to operate. Some smaller cars still in production remained built with the 6 volt system, like the Volkswagen Beetle in the 60’s and the Citroen 2CV in the 70’s. In 1990, a proposal was made for a standardized battery voltage of 42 volts for all the technology to come, including hybridization.

                                Lead – acid battery

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Today’s common car battery is a rather simple and ingenious way to deliver electricity to a car and recharge efficiently without wasting too much power. To deliver and receive power, a car battery uses reversible chemical reactions to make this happen. Inside a car battery, there are a series of sandwiched chemical plates mostly composed of lead and its alloys immersed in a mixture of water and sulfuric acid with 65% water and 35% of sulfuric acid. That still is a very concentrated mixture, so extreme care is necessary when there is any sign of a battery leak, but today’s batteries are permanently sealed most of the time, so that should keep us safe. The sandwiched chemical plates are made of lead, the positive plate of the battery and lead dioxide, which is the negative plate. The plates are put together to make a cell with each pair. Each cell produces around 2 volts. The larger the number of cells, the more voltage the battery has. Today’s common car batteries have a 6 cell layout, delivering a voltage of 12 volts.

The solution of sulfuric acid and water is called an electrolyte, a liquid that consists of random positive and negatively charged molecules as well as particles that are from the constituents of the electrolyte and they react with the materials immersed in it. For those who know their chemistry, forgive my crude explanation because I want to make the point simple to understand for others, including myself. The random positive and negative particles, or ions, consist of negative sulfate ions (SO4), positive hydrogen ions (H) and electrons (e). The lead and lead dioxide plates react with these ions to discharge electrons for the functioning of electric and electronic parts, but the real phenomenon happens when a circuit is complete. Electrons flow out of the battery via the negative lead discharged by the lead plates and electrons generated by electromagnetic means get to the positive lead and flow out of the lead dioxide plates at a certain voltage in the battery. This completely reverses the reaction, dispersing ions from the battery plates and electrons to be used again to continue the cycle. Absolutely brilliant, isn’t it?

                            Lithium ion batteries

 

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There is an alternative to lead – acid batteries though. They are lithium ion batteries. Found in our many of our daily items, most notably digital products like phones, laptops and more, this kind of battery has been adopted for automobile use. The reason is because these batteries have good characteristics. They are reliable, don’t discharge very quickly and the biggest selling point, their weight. These batteries are much, much lighter than lead – acid batteries and this trait is crucial for one branch of cars. Electric and hybrids.

Just like the lead – acid battery, a reversible chemical reaction takes place in this type as well. Except that there are no fluids present. Lithium is highly reactive and it reacts violently to water, so a non – aqueous electrolyte is used. This electrolyte in question is usually a mixture of organic carbonates containing various lithium ions. Again, forgive my terrible chemistry, as this is a little too much for me to properly understand. These organic carbonates and lithium ions react with the lithium metal in the battery, discharging electrons at a certain voltage through the negative lead. For the battery to get recharged, a high voltage is supplied to the positive lead. The chemical reaction gets reversed when electrons make random ions stable and the cycle continues.

These batteries are great at what they do and they are also very efficient. Yet, the problems make them a questionable power source. First off, they cost a lot to make. Lithium ion batteries are manufactured in a delicate and expensive process, making their prices even higher when they hit the markets. Secondly, there are the bad properties. Lithium batteries are prone to fire and exploding when handled incorrectly. They also need strong casings to ensure rigidity. Finally, and the worst is the depletion of the Earth’s resources. Because the properties of lithium enable it to be made into efficient batteries, humans are digging even deeper into our planet and excavating the metal, not to mention the incorrect recycling of it sometimes.

Lithium ion ones are used in bulk amounts to power electric and hybrid vehicles. The battery pack of one of these cars is usually about as large as a desk top and thick as a mattress. They have a high density to output ratio, obviously promoting their usage. But with most of the world’s products using these batteries, the future of portable electricity is something to harbor doubts about.

I will end this post here. I will write more about cars and parts. Stay tuned.

Happy Driving!

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