Comparison of the advantages and disadvantages of the four power battery technology routes

A, hydrogen fuel cell industry chain

In hydrogen fuel cell industry chain upstream is the production, transportation and storage, hydrogen at filling stations for hydrogen fuel cell system for hydrogen filling; Middle is the production of key components, such as electric pile, the pile and accessories of two parts for integration, form a hydrogen fuel cell system; In the downstream application level, mainly include transportation, portable power supply and stationary power three directions.

Second, power battery compares the advantages and disadvantages in

At present in terms of transportation with a power source, there are four main technical route: Lithium ion batteries, hydrogen fuel cells, supercapacitors and aluminum air battery. The lithium ion battery, super capacitor and hydrogen fuel cells has been widely used, and the aluminum air battery was still in the stage of laboratory research. Energy supply, lithium ion battery, super capacitor applies to pure electric vehicles, but need external charging, while hydrogen fuel cell vehicles need external hydrogen filling, aluminum air battery needs to be added aluminum and electrolyte.

Four kinds of technical route of comparing the advantages and disadvantages

Hydrogen fuel cell characteristics

(1) a good environmental compatibility

Hydrogen fuel cell is efficient clean energy, the discharge of water not only quantity is little, but very clean, so there is no water pollution problems. At the same time because of the fuel cell is not like the engine to heat energy into mechanical energy, but directly to convert chemical energy into electrical energy and thermal energy, high energy conversion efficiency, low noise.

(2) good operating performance

Hydrogen fuel cell power generation, do not need complicated configuration of the device, battery pile can be modular assembly. For example, a 4.5 MW power generation unit can have 460 battery components, the plant covers an area of much smaller than coal-fired power plants. Hydrogen fuel cell is suitable for distributed generation device. And compared with thermal, hydro andspecial power, hydrogen fuel cell power plant construction period is short, easy expansion, can be completely according to the actual need in installment construction. The operation of the hydrogen fuel cells are of good quality at the same time, the response to the rapid changes of load, such as peak load characteristics, in a few seconds can be from low power transformation to the rated power.

(3) the efficient output performance

Hydrogen fuel cells work when the fuel stored energy into electricity and heat, convert electrical energy efficiency is above 40%, and only one third of the steam turbine can be converted into electricity.

(4) flexible structural characteristics

Hydrogen fuel cell assembly is very flexible, easy to allocate, power size compared with the traditional engine, due to the hydrogen fuel cell good modularity can without any increase in infrastructure investment, on the basis of using single cell can be easily piece number increase or decrease the output power and voltage adjustment, so it is easy to build, and relatively easy to implement for grid control. This feature can improve the system stability of the fuel cell.

(5) hydrogen sources

Hydrogen as a secondary energy, can be obtained from a variety of ways, such as hydrogen production from coal, natural gas reforming hydrogen production, hydrogen production by electrolysis of water, and so on. In the fossil energy is exhausted, will become the world's main hydrogen fuel and energy. And use solar hydrogen production by the electrolysis of water in the process of no carbon emissions, can be thought of hydrogen energy is the ultimate.

(6) the bottlenecks

From the point of development at present stage, the popularity of hydrogen fuel cells with certain bottlenecks, such as the battery itself cost is higher, the infrastructure has not yet universal, etc.

Lithium ion battery characteristics

(1) voltage platform

Lithium ion batteries due to the anode materials are different, the monomer battery voltage in the range of 3.7 ~ 4 V, the application of the larger lithium iron phosphate monomer battery voltage of 3.2 V, is 3 times of Ni-Mh batteries, lead-acid battery 2 times.

(2) is greater than the energy

The current passenger car lithium ion power battery energy density of nearly 200 wh/kg, is expected to reach 300 wh/kg in 2020.

(3) the short battery life

Due to the restriction of electrochemical materials properties, lithium ion battery cycles no breakthrough, in the case of lithium iron phosphate, monomer battery cycles can reach more than 2000 times, only after the group for more than 1000 times. Unable to meet the requirements of bus run 8 year period.

(4) the influence to the environment

Lithium ion battery using light metal lithium, although do not contain harmful heavy metals such as mercury, lead, is considered to be the green battery, less pollution to the environment. But in fact as the anode materials and electrolyte containing nickel, manganese and other metals, the United States has the lithium ion battery to be classed as a kind of contains flammable, leaching toxic, corrosive, reactive toxic hazardous battery, is the most toxic substances contained in the various types of battery cells, and because the recycling process is more complicated, leading to high cost, so the current recycling utilization rate is not high, disused battery influence to the environment.

(5) the cost is still high

Lithium ion battery initial cost is high, at the current mainstream bus with power battery products lithium iron phosphate batteries. For an example, the price is about 2500 yuan/kWh, with the popularity of electric cars, in 2020, is expected to be reduced to less than 1000 yuan/kWh. Due to the restriction of monomer battery group cycles, the bus usually in 3 years or so, the need to replace batteries, operating unit cost pressure.

(6) larger influence on grid

First large-scale application of pure electric vehicles, due to the charging demand is bigger, charging equipment for grid harmonic interference will be highlighted, affect the quality of power grid power supply; Secondly, in the quick charge, because it is big charge ratio, therefore charging power is higher (passenger car in about 50 kw, buses in 150 ~ 250 kw), bigger impact load on the grid.

Therefore, based on the technical level of the lithium ion battery, the electric car is mainly in the range of the application of less than 200 km of short of pure electric vehicles.

The super capacitor characteristics

(1) high charge and discharge rate

Super capacitors with high power density, it can be released in a short time a few hundred to several thousand amperes of current, charging speed, it can be finished in a few seconds to a few minutes the charging process. Super capacitance bus and tram is to use this feature in a short period of time to complete charging, drive the vehicle to move forward.

(2) long cycle life

Minimal loss of super capacitor charge and discharge process, so its cycle life is infinite in theory, the actual can reach more than 100000 times, 10 to 100 times higher than the battery.

(3) the low temperature performance is good

Super capacitor charge and discharge occurred in the process of charge transfer on the surface of the electrode active material, mostly attenuation is very small, so the capacity with temperature and usually lithium ion battery capacity attenuation amplitude in the low temperature as high as 70%.

(4) the energy density is too low

One of the bottlenecks of the application of super capacitor energy density is too low, only about 1/20 of the lithium ion battery, about 10 wh/kg. So you can't as main power electric cars, mostly as auxiliary power, mainly used for fast start device and braking energy recovery device.

Aluminum air battery characteristics

(1) the material of low cost, high energy density

Aluminum air battery cathode active material is abundant metal aluminum, cheap, environmental protection, the positive active material is oxygen in the air, the positive visual capacity is infinite. Therefore, aluminum air battery has the advantage of light quality, small volume, long service life.

(2) the key technology is not a breakthrough, has not yet out of the lab

Air electrode polarization and aluminum hydroxide precipitation problem is one of the important obstacles affect metal air batteries towards marketization, the improvement of the performance of the aluminum air battery in big bottleneck. It is at the laboratory stage, there is a big distance from the commercialization.

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