What types of batteries are commonly used in electric vehicles?

Lead-acid batteries & lithium ion batteries

Lead-acid batteries are cheaper, but they are bulky, heavy and they have a short life.

Lithium ion batteries can also be divided into two types, with individual voltages of 3.7V and 3.2V respectively, of which 3.2V polymer batteries are said to be safer than the other.

Lithium battery disadvantage is that the price is expensive, but light weight, small volume and longer life expectancy (as far as I know, lead-acid battery use daily after prosthesis, life should not be less than lithium electricity).

Research on capacitors: their life is relatively unlimited, but even the large capacity of super capacitor, their volume and weight compared with lead-acid batteries are several times larger, I think it is almost impossible.

Electric vehicles is power source of electric vehicle batteries, now the majority of electric vehicle are lead-acid batteries, lead-acid battery of low cost, high cost performance. The battery is called a lead-acid battery because it can be recharged and used repeatedly.

In 1860, Prantet of France invented the battery with lead electrode, which is the predecessor of lead-acid battery.

Those that can be used by electric bicycles have the following four power batteries, namely valve-controlled lead-acid maintenance-free battery, colloidal lead-acid battery, nickel-metal hydride battery and lithium ion battery.

Lead-acid battery

Because of its low price, abundant material sources, high specific power, mature technology and manufacturing technology, and high resource recovery, lead battery has been widely used and studied in various electric vehicles all over the world. Electric bicycle as energy saving, convenient, fast, comfortable, cheap, zero emissions of personal transport, has been widely accepted and brought to the attention of the relevant state departments. By the state council development research center, the national development and reform commission, ministry of construction, ministry of science and technology and other ministries involved in the light electric vehicle industry development strategy research group put forward "light electric vehicle industry development strategy research" report. The national ownership electric bicycle has amounted to more than 30 million vehicles. More than 95% of the electric bicycle with valve-controlled lead-acid batteries.[1]

Have the vast majority of commercialization of the electric bicycle is the use of sealed lead-acid battery, don't need to supplement moisture, often in use free maintenance. The main chemical reaction is: PbO2 + 2 - h2so4 - > 2 + PB recharge and discharge pbso4 + 2 h2o

When lead-acid battery is charged, the spongy lead at the positive and negative poles of lead sulfate releases the sulfuric acid components fixed in it into the electrolyte, which respectively becomes spongy lead and lead oxide. The concentration of sulfuric acid in the electrolyte keeps increasing. Otherwise discharge lead oxide in the anode and the cathode plate of spongy lead react with sulfuric acid in the electrolyte into lead sulfate, and the concentration of sulfuric acid in the electrolyte coming down. When the lead-acid battery is undercharged, the lead sulfate on the positive and negative plates cannot be completely converted into spongy lead and lead oxide. If the battery is undercharged for long time, lead sulfate crystallization will occur, which will sulfide the plates and worsen the battery quality. On the contrary, if the battery is overcharged, the amount of oxygen generated by the positive electrode is greater than the adsorption capacity of the cathode, which increases the internal pressure of the battery, resulting in gas overflow, reducing the electrolyte, and may also lead to the softening or shedding of the active material, greatly shortening the battery life.

The comprehensive performance has been greatly improved

In recent 10 years, the comprehensive performance of valve-controlled lead battery for electric bicycle has been greatly improved. Take the 6-dzm-10 battery as an example. In 1997, the capacity of this type of battery was insufficient, and the discharge capacity of 2h rate (5A) was less than 10Ah. The specific energy is low, and the specific energy of 2h rate is less than 30Wh/kg; Short life, cycle life of 100% discharge depth is only 50~60 times (before the capacity drops to 8Ah; The following is the same as), the service life of only 3 to 5 months and other problems.

By 2003, 2 h rate discharge capacity (5 a) 11 ~ 13 ah; 2 h rate than energy reached 33 ~ 36wh/kg; 100% depth of discharge of the cycle life of 250 ~ 300 times, the service life can reach more than 12 months. Electric bicycle with valve-controlled lead-acid battery problems solved basically.

Deep cycle life performance of this type of battery is new, breakthrough. Main show is: 2 h rate discharge (5 a) initial capacity of 14 ah; 2 h rate than energy 38wh/kg; 100% depth of discharge cycle life of more than 400 times, sent out a total capacity of 4500 Ah, the corresponding total mileage of about 18000km (with 4 km/Ah, the same below). The deep cycle life of more than 600 times, sent out a total capacity of 6151 ah, the corresponding total mileage of about 24600km. If the capacity is lower than 7 ah life ending flag, deep cycle life of 943 cycles, sent out a total capacity of 8710 ah, the corresponding total mileage of about 34800km. If according to the deep cycle life of 250 times or out of a total capacity of 2250 ah, the corresponding total mileage of 9000 km of the battery pack can be used guarantee 1 year. [1]

Attach importance to match with charger

In years of practice, the whole vehicle manufacturers and battery manufacturers of electric bicycles have gradually realized the importance of matching the battery with the relevant equipment of the electric drive system, especially the charger. Manufacturing quality is the premise of battery quality, but only in the use of its matching charger can play a high quality battery should have superior performance, otherwise the high quality battery cannot fully play its potential superior performance. [1]

Different manufacturer of battery in the formula, structure, acid concentration and other differences, the appropriate charging parameters are different. For example, in our study, we found that different manufacturer battery charge in the stage of constant pressure parameters can vary from 1.5 V to 2.0 V (36 V battery).Proper charging parameter basic requirements are: to ensure that the battery can be full of, not due to owe charging battery capacity of normal attenuation; And make sure the battery during the whole life will not caused by charging battery severe water loss and thermal runaway. [1]

Pure electric vehicle lead-acid batteries

Early opening of the pure electric vehicle type lead-acid batteries adopted the "8 · 5" plan during the research, has made available to the successful experience of 19 months (120000 km), the key is accumulated a good control of charging methods, the depth of discharge, the filling water in time a system that matches the work experience and careful maintenance experience. In recent years, four-wheel vehicle (including tourist car, car, golf carts, short road car, etc.) development soon, the car USES the most is the open type lead-acid batteries. Corresponding models of battery get the favor of battery manufacturers. [1]

Electric car uses a valve control type sealed lead-acid battery of new products, its performance is: the rate of 3 h 55 ah capacity; 3 h rate under specific energy for 33 84wh/kg and WH/L;75% of the depth of discharge cycle life reached more than 400 times. Believe that the electric bicycle with valve-controlled lead-acid batteries successful experience can be extended to pure electric vehicle valve-controlled lead-acid batteries, the performance will be further improved. [1]

Hybrid electric vehicle lead-acid batteries

Hybrid electric vehicle is divided into three categories: basic now mild hybrid (namely the electric system is mainly used for starting and braking energy recycling, the promotion of the 42V electrical system on all cars belong to this type), moderate hybrid (that is, the electric system is used for starting, braking energy recycling and driving, short), severe hybrid (i.e. electric system used for starting, braking energy recycling and relatively long distance driving, also known as the "plug-in").[1]

It has been specified in the domestic and foreign documents: in a mild hybrid electric car, valve-controlled lead-acid batteries have advantages, mainly because of its low cost, mature technology, reliable performance. Mild hybrid electric car with valve-controlled lead-acid batteries, ALABC (advanced lead-acid battery consortium) is organizing development, preparation and MH - Ni battery for a mild hybrid electric car market, has now launched and the vehicle test coiling bipolar ear batteries and TMF (metal film) battery. In the field of heavy hybrid electric vehicle, low specific energy of lead battery, cannot satisfy the requirement of the electric system is relatively long drive.[1]

Colloid storage battery

It is an improvement of ordinary lead-acid battery with liquid electrolyte. It uses gel electrolyte, there is no free liquid inside, in the same volume of electrolyte capacity, thermal capacity, thermal dissipation ability is strong, can avoid the general battery easy to produce thermal runaway phenomenon; Low electrolyte concentration, weak corrosion of plate; Uniform concentration, no acid stratification phenomenon.

Nickel metal hydride battery（Ni-MH）

Ni-MH battery is battery family rookie emerged in the ninety s, developing rapidly. Ni - MH battery electrode reaction is:

The positive: Ni (OH) 2 + OH - = NiOOH + H2O + e -

Negative: M + H2O + e = MHab + OH - Ni (OH) 2 + M = NiOOH + MHab

It and nickel cadmium battery belong to alkaline battery, just to hide the hydrogen absorption of alloy material (MH) instead of the nickel cadmium battery anode materials of cadmium CD, electromotive force is 1.32V. It has all the excellent properties of the nickel cadmium battery, and the energy density is higher than that of nickel cadmium battery. Main advantages are: high specific energy (one time charge can exercise long distance); Higher than power, when large current work can also smooth discharge (accelerated climbing ability good); Low temperature discharge performance is good; Long cycle life; Safe and reliable, and free maintenance; No memory effect; There is no any pollution to the environment problem, renewable use, comply with the concept of sustainable development. However, Ni MH battery - cost is too high, too expensive.

Lithium-ion batteries

Lithium-ion battery is a new type of high-energy battery which was first introduced to the market by SONY in 1990. Its advantage is higher than the energy, is the current than the highest energy storage battery. It has won the popularization and application in portable information products.

Lithium-ion batteries are generally considered to have the following advantages: bigger than energy; Higher than the power; Uniformity; No memory effect; Good cycle characteristics; Is discharge rapidly, and the high efficiency; Wide working temperature range. No environmental pollution and so on, therefore is expected to enter the best power source in the 21st century. Is expected in the period 2006 ~ 2012, when the further development of lithium ion batteries, MH/Ni battery market share will shrink. Lithium ion market share will be enlarged. Electric bicycles with lithium-ion batteries are already on sale.

Driven by the development of new and cheap anode materials with good safety, good cycling performance and high specific capacity, the lithium ion battery used in electric bicycle is nearly practical. Several already offer more mature lithium-ion batteries for electric bikes equipped with battery management systems (BMS). There are also specialized in the production of lithium-ion batteries for electric bicycles manufacturers. The author thinks that the lithium ion battery used in the electric bicycle will be the first power battery to be used commercially and in large quantities in the vehicle. It will be a large proportion of practical batteries after the lead battery, but also for high-end electric bicycle products battery. There have been many reports on the trial and demonstration of large lithium-ion batteries in pure electric cars and buses, as well as in hybrid electric cars. According to the current level of lithium-ion battery development and experience, that electric bicycle with 48 v10ah below the safety of the battery pack is guaranteed, but large lithium-ion batteries to use in the commercialization of electric vehicles also do a lot of hard work, the main reason is that the pure electric cars and electric buses, as well as using hybrid electric vehicle battery quantity and complex system, security difficulty bigger, higher request of reliability and consistency, the price is too high. Reports that BYD, a Shenzhen-based company, would start a fleet of 200 electric cars powered by lithium-ion batteries in 2005 have been delayed until 2007. [1]

A fuel cell

Fuel cells convert chemical energy directly into electricity supply motor to drive the vehicle. Its main advantages are: high efficiency and can save fuel; Zero emissions; Low noise, etc., especially suitable for vehicle power supply. Hydrogen fuel cell car would be ideal and eventually replace petroleum products for fuel cars.[1]

Zinc - nickel battery (zinc - Ni)

Zn- Ni battery was once considered to be the battery for electric vehicles that should be advocated. From four to five years of market screening, there is little use in commercial electric vehicles. During the cycle, the initial capacity attenuation rate is large, which affects the actual service life of the battery. In addition, the rapid development and price reduction of lithium ion battery make Zinc - Ni battery application in electric vehicles more uncompetitive.

Zinc air battery

Zinc-air battery is a kind of metal-air battery, which belongs to the category of semi-fuel cell. It has the advantages of high specific energy, abundant raw materials, low price and no pollution, and is considered as a competitive candidate for electric vehicle batteries.

Chinese-Americans have set up PowerZinc, a company in Shanghai that makes empty cells that can be charged with zinc, and have built demonstration workshops. The electric bicycle and electric motorcycle manufactured by the company have been loaded with zinc empty battery for mileage test, reaching 150km and 250km respectively, and a lot of promotion and application work has been done. 50 battery replacement points have been set up in Shanghai. But no more than one year, the promotion trial work stopped, because it was not accepted by users. Later, with the support of some leaders, an electric bus was built with the zinc-empty battery as the power source. However, limited by the high power performance of zinc-empty battery, the startup and acceleration performance of the bus were obviously poor. A lot of work has been done in developing zinc-air batteries for electric vehicles at home and abroad. In recent years, the development of domestic electric vehicle zinc empty battery work again. However, the practice proved the advantages of zinc empty battery, but also exposed problems overseas have reported, such as zinc electrode replace the service system and regeneration cost and oxygen electrode, the life of a battery electrolyte leakage, creep leakage or overflow, etc.

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