Why don't mass-produced cars use lightweight lithium-ion batteries?
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Why don't mass-produced cars use lightweight lithium-ion batteries?

Holding a jump starter (car power bank - there are many names) weighing a couple of kilos, you can't help but wonder: why aren't such things installed as standard in cars? A small and lightweight device can start the engine of both a microcar and a heavy SUV.


After all, it seems that the main thing is to start the car, and then the generator comes into play, which supplies power consumers with current. Yes, indeed, once upon a time, to start an internal combustion engine, a little voltage and a “crooked starter” were enough. In principle, a battery capable of producing 5-10 volts at a current of 3-5 amperes is enough to excite the generator winding. Turn the handle a couple of times - and off you go!

Why don't mass-produced cars use lightweight lithium-ion batteries?The VAZ-2101 has a handle start! Photo: youtube.com

Such a scheme works only on cars with primitive electrical equipment. On cars produced today, the battery is needed not only to start the engine. The battery, like a large capacitor, smooths out current pulsations, ensuring its stability. If the crankshaft speed drops, the battery will maintain the required voltage. And its strictly defined value is very important for electronic components - microcircuits, for example. It makes no difference for a filament bulb or a rear window heater grid - 11 volts or 14,5. Delicate electronics will not tolerate such a spread.

The Porsche GT2 RS comes with a lithium battery from the factory. Photo: youtube.com

In cars of a higher class and an earlier year of production, everything is tied to a digital bus. Before starting the engine, the ECU polls the sensors and only then gives a command - to allow the start or not. This is not to mention the fact that an attempt to start the engine by pushing can "kill" the electronics. Removing the terminals from the battery with the engine running will also lead to problems. But let's get back to lithium-ion batteries: are they really not installed on serial cars at all? They are, but the list of such cars is very small and mainly these are sports and (and) expensive cars like the Porsche GT3/GT2. We are not talking about electric cars: it will not be possible to use a different type of battery there.

How lithium-ion batteries are designed and how they work


Pure Li is not included in the composition of such batteries: oxides with cobalt, nickel, phosphates, iron, manganese are used. The cathode is made of these materials. The anode is made of graphene or graphite. The role of the electrolyte is played by lithium salts with organic solvents.

The first batteries based on Li cobaltites appeared in 1983. Since then, the batteries have been continuously improved: the number of charge/discharge cycles has been increased from 300 to 7 thousand, the specific capacity – to 240 or more kWh/kg of mass, and the price has been reduced by about 10 times.

Interestingly, lithium-ion batteries do not have many advantages, and, first of all, this is low weight and dimensions. For example, if a lead battery of 90 A*h weighs about 24 kg, then a battery based on Li is only 5 kg. This indicates that such batteries have high energy capacity. A couple more advantages are the ability to quickly charge and, if necessary, quickly give current, as well as a low "tendency" to lose capacity when not in use.

The inscription 1000ССА means: the battery produces 1000 A*h at a cold start. Photo: youtube.com

And the last thing is the absence of any maintenance throughout the entire service life. However, modern lead-acid batteries also do not require intervention throughout the entire life cycle if the rules of use are observed. And now - about the disadvantages, which predetermined the reluctance of car manufacturers to install these batteries on mass-produced cars.

Disadvantages of Lithium-ion batteries


The first place can be given to a strong dependence on the ambient temperature. Overheating above 60°C and deep discharge are especially dangerous. It's all about the design. When the battery operates under normal conditions, there is a graphite layer on the anode that protects against aggressive electrolyte. When the temperature increases or the battery is heavily discharged, the coating is destroyed. And when the normal operating conditions are restored, the layer will be formed anew due to graphite and lithium. In fact, the characteristics of a "classic" battery of this type will deteriorate by 4-6% every year. In addition, severe overheating threatens an explosion: remember the recent terrorist attacks in Palestine, when gadgets overheated batteries and pagers were blown to pieces by a signal from the outside.

A lithium battery consists of several cells connected together. Photo: youtube.com

The next point is that the presence of cobalt in the design of a lithium battery is dangerous to human health and the environment as a whole. Therefore, after the end of its service life, such a battery must be disposed of. And this is not to mention the cost of the products: it can reach hundreds or more thousands of rubles. So is it really true that lithium batteries are banned from mass-produced cars? Not everything is so bad: manufacturers are confident that such batteries are the future and are working hard to improve them in all “minus” positions.

Lithium Iron Phosphate Batteries LiFePO4


This is what the famous phrase "if you can't, but really want to, then you can" means. Such batteries, compared to "classic" lithium ones, have a number of advantages. And the first of them is the temperature range, which is from -30 to +55°C. Even in severe frost, LiFePO4 retains 70% of its capacity. And what about overheating? There will be no open flame or explosion, but smoke will pour out. Cobalt is not included in the battery: this is also a plus from an environmental point of view.

Battery LiFePO4 LiitoKala 12.8V 60Ah. Average price: 23 thousand 432 rubles. Photo: market.yandex.ru

In terms of weight, the battery will be heavier than its “pure” lithium “colleague”, but lighter than its lead-acid counterpart. For example, the weight of a 60 A*h battery is 5 kg. As for the price, it is within the range of 23-40 thousand rubles for a battery for a passenger car. car. But even if you decide to “keep up with progress” and want to install such a battery on your car, you won’t be able to do it just like that.

Nuances of lithium batteries


They consist of several cells, usually with a voltage of 3,2 V: i.e. four pieces will give exactly 12,8 V. However, here each element "lives its own life". Therefore, in order for the charging/discharging process to be balanced, a controller will be needed. Otherwise, the service life of the product will be rapidly reduced.

Theoretically, and practically, the "brains" of a car can be reprogrammed for a lithium battery. But it is better to do this with specialists, and how much they will charge for the service is another question...

The second point is that lithium batteries are very sensitive to shaking and vibrations, which cause corrosion at the cell connection points. A car is not a phone that lies in a pocket or purse and is not subject to strong shaking.

Today, the controller can be integrated directly into the battery. Photo: youtube.com

But you can do the opposite, i.e. replace the lithium battery with a lead one in “emergency cases” (as written in the instructions for the McLaren MP4-12C). Yes, the car’s electronics will “go crazy”, the “check” light will come on, but the engine will start and you will get to the service center.

Lithium batteries can be made the same size as lead batteries for ease of installation. Photo: youtube.com

Nevertheless, despite everything, the number of fans of progress in the matter of lithium batteries is not only not decreasing, but growing. A lithium battery can be assembled even independently, in artisanal conditions, by buying individual elements and assembling them into a battery. Or ask a "specialist" from a neighboring garage to assemble the battery.

You can install LiFePO4 in a regular car, but...be careful. Photo: youtube.com

He will probably say that nothing needs to be reflashed, but at the very least, electronic protection against deep discharge will have to be installed. There is a demand for such products and it is even growing. Self-made lithium batteries are used by fans of racing on tracks in cars like Renault Megane RS, when losing ten or fifteen kilos would not be at all superfluous. By the way, for a 2-liter internal combustion engine, a battery with a capacity of … 10 A*h is enough.

All the possibilities of the sporty Renault Megane RS with a lithium battery

But still, we strongly advise against doing such "homemade work". Safety first!
What do you think about lithium-ion batteries in regular cars?
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