Last year, the global ban on fuel vehicles was announced, which made people realize that the era of new energy vehicles is coming. Why have pure electric vehicles, plug-in hybrids, fuel-powered cell vehicles and so on become the main theme of the future in just a few years? On the one hand, the global strategy, policy support, on the other hand is power and continuous increase of lithium-ion battery technology, longer life, shorter charging time, direct users about commuting requirements, to make the new energy vehicles came to our side, will replace traditional fuel cars in the future, is closely connected with our daily travel.

Lead-acid battery

Lead-acid batteries were first used in pure electric vehicles. Lead and its oxides were made as electrode materials, and sulfuric acid solution was used as electrolyte. This is the power source of most electric bicycles now, and low cost is its biggest advantage. However, because of the low energy density of lead-acid batteries, which bring about problems such as large volume and small capacity, they cannot meet the self-weight control of a car, the consumption of driving force, and even the service life of more than 10,000 kilometers per year, so they cannot be used in mass production cars on a large scale, and are eventually eliminated by automobile manufacturers.

Sealed lead-acid battery pack

Nimh batteries

Nickel metal hydride batteries and is very close to our daily life, from the early with sound heard now common rechargeable toothbrush and other small appliances, is extremely nickel metal hydride compounds, negative extremely metal hydride, its energy density, charge and discharge times than lead-acid battery has a lot of ascension, and electrolyte nonflammable, safety guaranteed, manufacturing processes mature, BYD was the world's second-largest maker of nickel-metal hydride batteries before it built cars.

Nickel-metal hydride battery pack

However, because the nickel-metal hydride battery charging efficiency is general, there is a charging memory effect, the working voltage is low (can not use high pressure fast charging), is not suitable for a single power source of the car, suitable for auxiliary engine work. This best should belong to Toyota, the hybrid system USES atkinson engine + nimh battery pack, the atkinson engine itself has the middle speed range and efficient advantages, but also has the weak low speed and high speed, and nimh batteries can be solved just started with a great addition to the lack of motivation at a high speed.

After the lithium ion battery is widely used, the nickel metal hydride battery also has the trend to be completely replaced in the automobile. For example, Toyota's new generation hybrid system adopts the combination of more efficient engine + lithium ion battery. Compared with lithium-ion batteries, nickel-metal hydride batteries do not have advantages in capacity, cycle charging life and environmental protection. The cost advantage is weakened under the vigorous development of lithium-ion batteries, which is the reason why nickel-metal hydride batteries are gradually withdrawn from the automotive field.

Lithium-ion battery

Lithium ion battery is the mainstream choice of new energy vehicles at the present stage. Lithium compounds (lithium manganese acid, lithium iron phosphate, etc.) are used as electrode material, and graphite is used as anode material. Its advantages are high energy density, small size, light weight and high charging efficiency. The important factor that determines the type or performance of lithium-ion batteries lies in the materials of the battery poles, among which the material of the positive electrode is the key at this stage, such as the mainstream lithium iron phosphate, lithium cobalt oxide in ternary materials, nickel cobalt manganese and so on. There are differences in capacity, cost, low temperature charge and discharge, safety and other dimensions.

General Motors Group Lithium Ion Battery Pack

But cold temperatures are a natural enemy for all lithium-ion batteries of any type. Although there are certain differences in the optimal operating temperature of different types of lithium-ion batteries, the activity of lithium ions decreases when the temperature is lower than the optimal range, which has a great impact on the range of battery life, which is also reflected in our previous tests: Electric vehicles equipped with lithium-ion battery packs can only reach more than 60% of the theoretical range in winter in northern China, or about 70% at most.

Tengse EV400 extreme range test results

The negative impact of low temperature from the battery itself is not very good solution, so many car makers to find a way to give battery heating, the new temperature control system for power lithium batteries alone, the vast majority of this approach brand models have a certain ease use, but the actual effect is not good to solve the problem, because there are some power consumption for the temperature control system of ev, More than the loss of low temperature.

Emgrand EV450 is equipped with version 2.0 of ITCS battery intelligent temperature control management system

In this regard, it is expected that GM will cooperate with South Korea's LG Group to purchase products that can be equipped with multiple temperature control components directly inside the battery pack, not only to heat the battery as it does now, but also to raise the temperature of the battery in cold weather. The technology is expected to be used in GM's next round of pure and plug-in hybrid cars, replacing the current Hitachi battery packs.

Hydrogen fuel powered cells

You know what happens when you burn H2+O2, so hydrogen is an ideal source of clean energy. In the case of hydrogen itself, the energy released by combustion, its performance at low temperatures and, most importantly, the efficiency of hydrogenation, which can travel more than 600 kilometers in just five minutes and has room to improve, are far better than existing lithium-ion batteries.

Regarding the investment of hydrogen fuel-powered cell vehicles, Japanese and South Korean car companies have long started the research, and now they have put into their respective markets on a small scale. For example, the author's test drive of Hyundai Nexo hydrogen fuel-powered cell car before the Spring Festival has been largely used in the Pyeongchang Winter Olympics and marketed.

Hyundai Nexo hydrogen fuel-powered cell car

And hydrogen is such a good source of energy, why not promote? Because it's just too difficult to get hydrogen with the current technology. You've all learned that electrolyzing water makes hydrogen, but using electricity to electrolyze water and then burn hydrogen to turn it into water doesn't take as much power and loss as charging a lithium-ion battery, which is expensive. The cost and process are more appropriate to extract from oil and natural gas, but the amount is not large, so fuel powered cell vehicles only hear its name, difficult to promote.

Graphene cell

The most reliable and most discussed lithium battery for new energy vehicles in the future is graphene battery. Some professional interpretation translation is: There are two ways to use this material combined with lithium-ion battery. One is to use graphene composite material as the conductive agent of lithium-ion battery; the other is to use it as the negative electrode directly. The effect is to increase the activity of lithium-ion battery, so as to improve the range and charging speed of electric vehicles.

Graphene-carbonized sponge lithium oxygen battery

Graphene batteries can effectively solve the shortcomings of lithium-ion batteries, and the product characteristics are directly linked to the use of new energy vehicle users. This material is really big benefits, and South Korea's samsung has announced mastered the technique, but the cost is a big bottleneck, graphene access is not too easy, early is a material used in space, when, by what way to reduce costs, will be a big problem to the high quality products are flying off the shelves, None of the automakers has announced plans to do anything about it.

To put it simply, pure electric vehicles work by charging electricity directly, while hydrogen fuel-powered cell vehicles burn H2+O2 into (chemical reaction) electric energy and water, which is equivalent to burning hydrogen to generate electricity. Both types of batteries are also zero-emission. The lithium-ion battery of electric vehicles has smaller capacity density, poor low-temperature activity, which affects its range and slow charging speed. Hydrogen fuel power battery does not exist at all, and its working efficiency is much higher, which is the reason why hydrogen is called high-quality energy.

Solid state lithium ion batteries

Solid state lithium ion battery as the name suggests is no longer use liquid electrolyte, using solid electrolyte, the ability of the density than now the mainstream of the lithium ion battery, which means that the type of pure electric vehicles, achieve energy-saving petrol car range even higher, and charging efficiency compared to the present stage also has a qualitative leap, is equipped with solid state battery electric vehicles, The most ideal charging speed can reach an additional 800 kilometers per minute, which can be said to be the best core component of new energy vehicles.

Overseas energy and technology companies, as well as battery makers such as Panasonic, are now developing solid-state batteries. The only three major Japanese automakers involved in this field are Toyota, Honda and Nissan, which have been helped by the Japanese government. The parties already working on solid-state batteries are expected to see breakthroughs in cost, energy density and manufacturing by 2020. It is still a long way from 2030 before the results of this research and development can be widely used in new energy vehicles, which is why the automakers didn't mention solid-state batteries when they announced their strategies for a global ban on fuel vehicles by 2025.