Fuel cell VS lithium battery, which will become the important automobile power source

A few months ago, Elon Musk, tesla's chief executive, told the German press that FuelCell is "a FoolCell," telling them, "they're so stupid, even if it's theoretically foolproof, it won't match today's lithium-ion batteries." He also points out that lithium-ion batteries have a lot of untapped potential.

On the other hand, several auto giants, including gm and Toyota, have signed fuel cell development agreements with their partners, and plan to launch fuel cell vehicles in the next few years. Toyota unveiled its fcv-r hydrogen fuel cell concept at the Tokyo motor show in 2011, and this year's Tokyo motor show will feature production models. Toyota and BMW have signed an agreement to cooperate in four areas, including fuel cells.

In addition to Toyota, general motors and Honda motor have announced that they will jointly develop next-generation fuel cell technology for launch in 2020. South Korea's hyundai motor has pioneered fuel-cell vehicles, and ford, Daimler and renault-nissan are working together to develop fuel-cell technology.

Toyota said the fuel cell ModelS to be mass-produced will cost about as much as the BMW 5 series or tesla ModelS, at around $50,000, with a range of up to 300 miles (483km) on a single charge. So cost-effective with a high competitiveness.

So whether it's tesla's gelig or Toyota and a bunch of other automakers, why the battle between fuel cells and lithium-ion batteries, and what will power electric cars in the future? Let's do a deep dive.

Electric cars and conventional cars

Now numerous electric vehicles, in fact, is a continuation of the traditional car, people do, the traditional part of the car power, fuel part into the motor and battery.

Electric cars have a very, very long history. In 1839, Robert Anderson of Scotland fitted a battery and an electric motor to a wagon and turned it into the world's first electric vehicle. The invention of the internal combustion engine was delayed more than 40 years to October 1885, when Karl Benz designed and built the world's first three-wheeled gasoline car, and gottlieb Daimler produced a four-wheeled gasoline car that same year. The two formed their own car companies, which merged into daimler-benz in 1926.

The electric vehicle has experienced three development periods in the history, from 1885 to 1915 was the first golden age of the electric vehicle. During this period, as the internal combustion engine technology is quite backward, short driving range, many faults, maintenance difficulties, electric vehicles, electric vehicles in this period is generally recognized. The President of the United States was driven by an electric car, not an internal combustion engine.

In the second stage, in the 1960s, under the background of the oil crisis caused by the Middle East war, the United States general motors company and ford motor company respectively developed new electric cars. Citroen and Peugeot have converted existing models into small electric cars. As an opportunity, the world set off a wave of electric vehicles.

The third stage is the 1990s, with the progress of lithium battery technology, cost reduction, electric vehicle performance has been greatly improved. Finally achieved tesla, nissan and other mass production of electric vehicles.

It can be seen from the history of electric vehicles that electric vehicles and traditional internal combustion engine vehicles are actually developing in parallel and competing with each other. When the performance, cost and user experience of the electric vehicle are higher than that of the internal combustion engine, the electric vehicle will have a golden period of development. However, when the internal combustion engine technology advances and the user experience exceeds that of the electric vehicle, the electric vehicle will fall into silence.

A key factor in the performance of electric vehicles: power batteries

For electric cars, the key to whether performance, cost and user experience can overtake an internal-combustion car is the power battery.

We know, the car can run, because the engine and gearbox work, to provide power to the car, the electric car can run is the battery and electric motor to provide power. After a hundred years of development, motor technology has become very mature.

No matter be the power of unit weight, still be efficiency, life, cost, control, it is far better than engine. Motors of the same power tend to be cheaper than engines, last longer and are easier to maintain. In theory, electric cars should be far more competitive than internal-combustion vehicles, and the problem lies in the batteries.

As we all know, the movement of a car needs energy. The energy of an internal combustion engine car comes from the combustion of gasoline or diesel, and the heat energy is converted into kinetic energy. The battery USES a motor to convert electrical energy into kinetic energy. Now the problem with electric cars is that they have the same weight, the same volume, and they provide far less energy than gasoline or diesel, which means lower energy density.

So, also run 300 kilometers, gasoline car only need 30 liters of fuel tank, only need more than 20 kilograms of gasoline, and even if the use of advanced lithium ion battery electric car, also want more than 600 kilograms of huge battery pack, not to mention the protection circuit, the battery pack itself to protect the weight.

Lead-acid batteries require a heavy battery pack of one to two tons, compared with the normal weight of a family car.

In addition to energy density, there is also a concept of power density. The maximum current that a power battery can release is limited, and the voltage is limited. Even if the motor power is very high, the battery instantaneous discharge ability is not good, it will affect the performance of electric vehicles.

Classification of power batteries

At present, there are many kinds of power batteries for electric vehicles, but few of them are really practical. Because a lot of batteries have this or that problem. Most of the manufacturers in the world have chosen lithium batteries. Details include lithium ternary batteries, lithium iron phosphate batteries and lithium manganate batteries. However, they all come down to the category of lithium batteries.

Neither the hydrogen fuel cell nor the zinc air cell is a rechargeable battery. Instead, it consumes other materials (hydrogen and zinc) to generate electricity.

There are several more alternative battery, generally as a power battery auxiliary use. Below we will talk about the characteristics of various types of batteries and the advantages and disadvantages of the car.

Hydrogen fuel cell

First up, hydrogen fuel cells, which geligo lampooned as "dumb" cells. Fuel cells are not new. They date back to 1838, when a German chemist came up with the fuel cell theory. Really lead was in 1955, the United States ge engineers made practical hydrogen fuel cells, are then applied to the American duo of space exploration plan (digression, interested can search the documentary "from the earth to the moon", see the American duo plans, the Apollo program, and look at China's shenzhou program, the goddess of the moon plan).

Hydrogen fuel cells, developed in 1991 for use in automobiles, are the source of today's hydrogen fuel cells.

One of the biggest advantages of hydrogen fuel cells over other types of batteries is their high energy density. They can reach 3 kilowatt-hours per kilogram in the laboratory, which is much higher than other types of batteries. The car can be used in a smaller size and weight, providing longer battery life.

But there are problems with hydrogen fuel cells:

First, the price. The core parts of hydrogen fuel cell are proton exchange membrane and platinum catalyst, both of which are very expensive materials. They can be used inspecial regardless of the cost. The current price is 1.5 million to 2 million yuan, far higher than the fuel car and lithium battery electric cars;

Second, the source and storage of fuel. Hydrogen fuel cells need hydrogen, which is not supported by the industrial chain. It is extremely inconvenient to manufacture, transport, storage and refueling.

Hydrogen fuel cell vehicles have a long way to go from a user experience perspective. Geligo's satire of hydrogen fuel cells as "dumb cells" is not entirely unreasonable.

(2) zinc air battery

Zinc air batteries also have a long history, dating back to 1878. Zinc-air batteries are much more similar to the dry batteries we use, and in fact, zinc-air batteries are replacing dry batteries in many fields.

Zinc-air batteries have a higher energy density, up to 0.3 kilowatt-hours per kilogram, which is higher than lithium batteries and cheaper. Zinc is much cheaper than lithium.

But there are two problems with zinc-air batteries:

First of all, the power density is low. Although the range of the electric car using zinc-air battery is not inferior to that of the lithium battery electric car, its acceleration and climbing performance are very bad and its practicality is not good.

Secondly, the industrial chain does not match. Zinc air battery is similar to hydrogen fuel cell, and the material needs to be replaced. Zinc air battery needs to replace zinc oxide with metallic zinc, which requires a series of supporting industrial chain from power plant, electrolytic zinc factory, zinc battery factory, automobile battery changing station and so on. This is all starting from scratch, but it is also far less mature than lithium-ion batteries, and a long way from being practical.

(3) flywheel battery

Flywheel battery is a new type of battery developed in recent decades. It is not a traditional chemical battery that converts chemical energy into electric energy, but a battery that has a high-speed rotating flywheel inside and relies on the flywheel's kinetic energy to store energy.

The flywheel battery has no chemicals, no explosive combustion or other safety issues, and is not afraid of temperature changes, harsh environment and very long cycle life. What's more valuable is that the flywheel battery has a very high power density, up to 5-10kw /kg, which is much higher than other types of batteries. Although the energy density is similar to lithium battery, the high power density can bring excellent vehicle acceleration performance and can withstand more power when energy is recovered.

In a porsche 918 concept car, the co-pilot position is a flywheel energy storage system the flywheel battery is the only weakness is expensive, technology, performance, security, the flywheel battery is very suitable for car use, but the high prices were meant it could only appear on the luxury car or supercar, and could not enter the public with a car.

(iv) lithium battery

Lithium battery can be traced back to the 1970s, is the most widely used battery.

In fact, there are several types of lithium batteries for cars. The latest panasonic battery used by tesla is a three-way lithium battery. The three-way lithium battery has a balanced energy density, power density and safety.

The advantage of tesla is that it solves the security problem during charging and discharging with software. So that the original safety of the tri-lithium battery can be applied to the car.

However, tesla's power management technology cannot solve the puncture problem, so it can only be solved by strengthening the protection of the battery pack. In case of extreme collision, strong impact force breaks the protection of the battery pack, and tesla will still catch fire and explode, but the high-strength protection gives the owner time to escape.

lithium iron phosphate (byd's so-called iron battery) is a widely used battery. Its advantage is that it is relatively safe. It has good power density, high discharge rate and good acceleration performance. In terms of cycle life, lithium iron phosphate also has advantages. Its long-term use cost is relatively low.

The disadvantage of lithium iron phosphate is that it has a relatively low energy density and no advantage in the same weight and range. In addition, low temperature performance is poor, cold days will lose a lot of electricity.

In general, lithium iron phosphate is still regarded as a promising power battery.

Lithium manganate battery is widely used by Japanese enterprises. It has the advantages of better low-temperature performance, less severe low-temperature power loss than lithium iron phosphate, lower price and less safety than lithium iron phosphate, but it is not bad. But the material itself is not very stable, easy to produce gas.

Summary:

From the current technology, hydrogen fuel cell and zinc air cell need to build a new industrial chain to support, which will take a long time and a lot of investment, and both of them have weaknesses, weak competitiveness, will not have much hope for a long time.

Flywheel batteries are excellent, but expensive. If you can find a way to significantly reduce costs, flywheel batteries are the most suitable for electric vehicles. That means that for a long time to come, flywheel batteries will only be available in some ultra-expensive luxury cars and supercars.

Since the invention of lithium battery, with the progress of technology and the expansion of industrialization, every year there is a small range of price reduction and capacity improvement.

Tesla's popularity after 2012 was not due to its leading technology. In 2005, Japan developed Eliica with better performance than tesla ModelS, but the high price of lithium battery meant that this product was just a test product.

Byd is developing the E9 with performance comparable to tesla ModelS, and as a plug-in hybrid vehicle for electric and petrol-powered vehicles, byd qin will be on the market soon, BMW i3 and i8 will be on the market, and porsche 918 has been pre-ordered. The reason behind this is that in 2013, the price of lithium battery has been reduced to an acceptable range.

In the next few years, with the further decrease of lithium battery price and the further improvement of capacity, electric vehicles and plug-in hybrid electric vehicles will become cheaper and better, and the process of electric vehicles replacing fuel vehicles is just beginning.

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