Electric car battery definition, electric car battery source!

The electric vehicle battery is the power source of electric vehicles, now the vast majority of electric vehicles are loaded with a lead-acid battery, lead-acid battery cost is low, cost-effective. The battery is called a lead-acid battery because it can be recharged and reused.

In 1860, planted in France invented the battery with lead electrodes, which was the predecessor of the lead-acid battery.

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

Lead-acid battery

Because of its cheap price, abundant material sources, high specific power, mature technology and manufacturing technology, high resource recovery, the lead battery has been widely used and studied in many countries. E-bike as a labor-saving, convenient, fast, comfortable, cheap, zero emissions of personal transport has been widely accepted, and by the state, departments concerned. By the development research center of the state council, the national development and reform commission, the ministry of construction, the ministry of science and technology and other ministries to participate in the "light electric vehicle industry development strategy research" research group put forward the "light electric vehicle industry development strategy research" report. The number of electric bicycles in China has reached over 30 million. More than 95 percent of electric bikes use valve-controlled lead batteries. [1]

The vast majority of the commercialized e-bike is the use of sealed lead-acid batteries, the use of the need not often add water, maintenance-free. Its main chemical reaction is PbO2+2H2SO4+Pb charge, discharge 2PbSO4+2H2O

When a lead-acid battery is charged, lead in the form of sponge at the Yin and Yang of lead sulfate releases the fixed sulfuric acid into the electrolyte and turns into the lead in the form of sponge and lead oxide respectively. The concentration of sulfuric acid in the electrolyte increases continuously. On the contrary, when discharging, the lead oxide in the anode and the sponge lead in the cathode plate react with the sulfuric acid in the electrolyte to become lead sulfate, and the concentration of sulfuric acid in the electrolyte decreases continuously. When the lead-acid battery is undercharged, the lead sulfate on the anode and the cathode cannot be completely transformed into the spongy lead and lead oxide. On the contrary, if the battery is overcharged, the amount of oxygen generated by the anode is greater than the adsorption capacity of the cathode, so that the internal pressure of the battery increases, leading to gas overflow and the reduction of electrolyte, which 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 2h rate (5A) discharge capacity could not reach 10Ah. Specific energy is low, the specific energy of 2h rate is less than 30Wh/kg; Short life, the cycle life of 100% discharge depth is only 50~60 times (the capacity drops to 8Ah before; The following is the same. The service life is only 3~5 months.

By 2003,2h rate (5A) discharge capacity reached 11~13Ah. 2h specific energy reaches 33~36Wh/kg; The cycle life of 100% discharge depth can reach 250~300 times, and the service life can reach more than 12 months. The problems of vrla battery for electric bicycle have been solved basically.

The deep cycle life performance of this type of battery has made new and breakthrough progress. The main performance is :2h rate (5A) the initial discharge capacity reaches 14Ah; 2h specific energy rate reaches 38Wh/kg; The cycle life of 100% discharge depth is more than 400 times, the total discharge capacity is 4500Ah, and the corresponding accumulated driving range is about 18000km(in terms of 4km/Ah, the same as below). The highest deep cycle life is more than 600 times, the total discharge capacity is 6151Ah, and the corresponding cumulative mileage is about 24600km. If the life-ending mark is the capacity less than 7Ah, the life of the deep cycle is 943 cycles, and the total capacity released is 8710Ah, and the corresponding accumulated mileage is about 34800km. If the battery pack with 250 times of deep cycle life or a total capacity of 2250Ah and a corresponding accumulated mileage of 9000km can be used for one year. [1]

Attach importance to match with charger

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

Due to the differences in the formula, structure, acid concentration and other aspects of the battery from different manufacturers, the appropriate charging parameters are different. For example, in our study, we found that the charging parameters of different battery manufacturers in the constant voltage phase can differ by 1.5-2.0v (for 36V battery pack). The basic requirements for proper charging parameters are: to ensure that the battery can be fully charged, and not cause abnormal attenuation of battery capacity due to under-charging; It is also necessary to ensure that the battery will not cause serious water loss and thermal runaway due to overcharging during its full life. [1]

Lead battery for pure electric vehicle

The early open lead battery for pure electric vehicles adopted the research results during the "8 · 5" planning period and has obtained the successful experience of 19 months (120,000 km). The key is to accumulate the experience of controlling the charging mode, discharging depth, timely water replenishment, and other matching work and careful maintenance experience of a set of systems. In recent years, four-wheel miniature electric vehicles (including touring cars, patrol cars, golf carts, short-distance road vehicles, etc.) develop very fast, most of the cars are open lead batteries. The corresponding type of batteries by the battery manufacturers of all ages. [1]

The electric vehicle is a valve control sealed lead battery new products, its performance is: 3h rate capacity 55Ah; The specific energy was 33Wh/kg and 84Wh/L at a 3h rate. Cycle life of 75% discharge depth is over 400 times. It is believed that the successful experience of valve-controlled lead battery used in an electric bicycle can be extended to the valve-controlled lead battery used in a pure electric vehicle, and its performance will be further improved. [1]

Lead batteries for hybrid electric vehicles

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 42 v 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 made clear in domestic and foreign literature that in mildly hybrid electric vehicles, the valve-controlled lead battery has advantages, mainly due to its low cost, mature technology, and reliable performance. ALABC(advanced lead-acid battery consortium) is organizing research and development to compete with Mh-Ni batteries for the market of medium hybrid electric vehicles. It has launched and conducted an on-board test of wound bipolar battery and TMF(metal film) battery. In the field of heavy-duty hybrid electric vehicles, the specific energy of lead batteries is low, which cannot meet the requirements of long-distance driving of electric systems. [1]

Colloidal 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, heat capacity, heat dissipation ability, can avoid the general battery easy to produce thermal runaway phenomenon; Low electrolyte concentration, weak corrosion of plate; Uniform concentration, no acid stratification.

Nickel metal hydride battery

(Ni - MH)

Nickel-metal hydride battery is the emerging battery family in the 1990s, the rapid development. The electrode reaction of ni-mh battery is as follows:

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, but the negative material of nickel-cadmium battery cadmium CD, an electromotive force is still 1.32v. It has all the excellent characteristics of the nicad battery and its energy density is higher than nicad battery. The main advantages are: higher than the energy (a charge can be exercised over a long distance); High specific power, stable discharge even under high current (good climbing speed); Good low-temperature discharge performance; Long cycle life; Safe and reliable, maintenance-free; No memory effect; There is no pollution problem to the environment. It is renewable and in line with the concept of sustainable development. However, Ni-Mh batteries are expensive and expensive.

Lithium-ion battery

The 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 high specific energy, is the current specific energy of the highest battery. It has been widely used in portable information products.

Lithium-ion batteries are generally considered to have the following advantages: greater energy; High specific power; Small self-discharge; No memory effect; Good circulation characteristic; Rapid discharge and high efficiency; Wide operating temperature range; No environmental pollution, so it is expected to enter the 21st century the best power supply ranks. It is expected that the market share of MH/Ni batteries will shrink during the period from 2006 to 2012 when lithium-ion batteries are further developed. Lithium-ion market share will expand. There are already electric bicycles on sale with lithium-ion batteries.

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 bicycles equipped with battery management systems (BMS). There are also specialized in the production of lithium-ion battery electric bicycle 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, also will be used for high-end electric bicycle products battery. There have been many reports of large lithium-ion batteries being tested in electric cars and buses, as well as in hybrid electric vehicles. 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. It has been reported that BYD, a Shenzhen-based company, will offer a fleet of 200 electric cars powered by lithium-ion batteries in 2005, but this has been delayed until 2007. [1]

A fuel cell

The fuel cell converts the chemical energy directly into electricity for the electric motor to drive the vehicle. Its main advantages are: high efficiency, can save fuel; Zero emissions; Low noise, especially suitable for a vehicle power source. Hydrogen fuel cell vehicles would be ideal to eventually replace petroleum-based vehicles. [1]

Zinc-nickel battery (Zn-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. This is primarily because of the higher price of a Zn-Ni battery (2.5 to 4 yuan per VAh, which is 4 to 6 times higher than for a lead battery). 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 batteries make Zn-Ni batteries in electric vehicles more uncompetitive. [1]

Zinc-air cell

Zinc-air battery is a kind of metal-air battery, which belongs to the category of the 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 Power Zinc (Power Zinc) in Shanghai to produce mechanical zinc-charged air batteries, and have built demonstration workshops. The electric bicycle and electric motorcycle manufactured by this company have been equipped with Zn empty battery for driving range test, reaching 150km and 250km respectively. A lot of promotion and application work has been done, and 50 battery replacement points have been set up in Shanghai. But less than a year later, the promotion trial work stopped, and the result of market screening was not accepted by users. After that, with the support of some leaders, an electric bus was built with the zinc-empty battery as the power source. However, due to the poor high power performance of the zinc-empty battery, the starting and accelerating performance of the bus was 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-air battery work again, but the practice proved the superiority of zinc-air battery should be original, but also exposed some overseas has reported problems, such as zinc electrode to replace the service system and regeneration cost and oxygen electrode, the life of a battery electrolyte leakage, leakage or spill, etc.

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