Rechargeable battery is a rechargeable battery with limited charging timesChargeruse.The market generally sells No. 5 and No. 7, but there is also No. 1.The advantages of rechargeable batteries are economic, environmental protection, sufficient power, and electrical appliances suitable for high-power and long-term use (such asWalkman、Electric toysEtc.).The voltage of rechargeable battery is lower than that of disposable battery with the same model. The AA battery (charging No. 5) is 1.2 V, and the 9V rechargeable battery is actually 8.4 V.Currently, the charging times are about 1000.As of February 2012, there are only five kinds: nickel cadmiumni-mh 、Lithium ion, lead storage, iron lithium.
Lead acid batteryThe active substance on the positive plate isLead dioxideThe active material on the negative plate is sponge like pure lead, the electrolyte is sulfuric acid solution of certain concentration, and the electromotive force between the plates is about 2V.
The active substance on the positive plate of the nickel cadmium battery is nickel oxide powder, and the active substance on the negative plate is cadmium oxide powder. The active substance is wrapped in perforated steel strip respectively, and becomes the positive and negative plates of the battery after pressure forming.Electrolyte is commonly usedPotassium hydroxideThe open circuit voltage of solution and battery is 1.2V.
The positive plate material of nickel metal hydrogen battery is nickel oxide powder, the negative plate material is hydrogen absorbing alloy, and the electrolyte is potassium hydroxide solution.,The open circuit voltage of the battery is 1.2V. The lithium ion battery uses LiCoO2 composite metal oxide to form an anode on the aluminum plate and lithium carbon compound to form a cathode on the copper plate. There is a polyolefin film barrier with submicron micropores between the plates. The electrolyte is organic solvent. The open circuit voltage is 3.6V.
Lithium polymer battery is an improved type of lithium-ion battery. There is no battery liquid, so it is used insteadPolymer electrolyte, which is more stable than the ion battery. The open circuit voltage is 3.6V.
Common parameters
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The battery capacity represents how much power the battery can store. The number we see on the battery packaging generally refers to the battery capacity identification.It is expressed in ampere hours or milliampere hours.It is a composite unit, which is composed of the product of current unit and time unit, representing the ability of the battery to discharge continuously under constant current.A fully charged battery can be discharged for 10 hours with a current of 200mA. Multiply the current and time to get a capacity of 2000mAH。If it is discharged with 400mA, the available time is 5 hours.
Energy density: the electric energy capacity contained in the unit volume or unit weight. For the same power requirements, batteries with high energy density can be smaller in size and lighter in weight.
C Current: It refers to the current that will discharge the fully charged battery or fully charge the exhausted battery within one hour.In fact, it is the value of ampere hour capacity.For a battery with a capacity of 1800mA, C current is 1800mA.For a battery with a capacity of 2000mA, C current is 2000mA.
Open circuit voltage: refers to the potential difference between the two poles of the battery.
Memory effect: new battery, with fine grain of electrode material, can obtain the largest electrode surface area.Because of use, the contents of the battery will crystallize. After crystallization, the grains will increase, also known as (passivation), reducing the usable electrode area. Moreover, the growing grains will cause self discharge to increase, reducing the battery capacity and damaging the performance.This is the memory effect.The memory effect is caused by the incomplete repeated partial charging and discharging of the battery.
Self discharge rate: the charged battery will gradually lose its power even when it is not in use. Generally, the higher the temperature, the more obvious the self discharge.
type
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Nickel cadmium
（Ni-Cd）
Voltage: 1.2V Service life: 500 times
Discharge temperature: - 20 ℃~60 ℃
Charging temperature: 0 ℃~45 ℃
ni-mh
rechargeable battery
（Ni-MH）
Voltage: 1.2V
Service life: 1000 times
Discharge temperature: - 10 ℃~45 ℃
Charging temperature: 10 ℃~45 ℃
Note: At present, the maximum capacity of domestic No.5 battery is about 3000mAh.
Lithium ion
rechargeable battery
（Li-lon）
Voltage: 3.6V
Service life: 500 times
Discharge temperature: - 20 ℃~60 ℃
Charging temperature: 0 ℃~45 ℃
Note: The weight is 30%~40% lighter than that of the nickel hydrogen battery, and the capacity is more than 60% higher than that of the nickel hydrogen battery.However, it is not resistant to overcharge. If overcharge occurs, the temperature will be too high and the structure will be damaged=>explosion.
Lithium polymer
Voltage: 3.7V
Service life: 500 times Discharge temperature: - 20 ℃~60 ℃
Remark: The modified lithium battery is used instead of battery liquidpolymerElectrolyte, which can be made into various shapes, is more stable than lithium battery.
Lead acid battery
Single nominal voltage: 2V
Service life: 200~300 times
Discharge temperature: 0 ℃~45 ℃
Charging temperature: 0 ℃~45 ℃
Note: It is a general vehicle battery (it is connected in series with 6 2V to 12V). The water free battery has a service life of up to 10 years, but its volume and capacity are the largest.
Lithium ion: No memory effect, thin body and large capacity, due to different electrode materials,emfThey are 3.6V and 3.7V.The performance of lithium battery is the best among all kinds of existing batteries, with small size, light weight and large capacity.It is widely used in digital cameras, laptops, mobile phones and other electronic products.
Lead storage: the electromotive force is about 12V, the lead battery can be recharged repeatedly, and the electrolyte is sulfuric acid solution,internal resistanceIt is small and widely used in automobiles and motorcycles.
Iron lithium: more sufficient power, safer, lighter, futureElectric vehicleThe main direction of development.
Generally, rechargeable batteries of the same type have larger capacity, larger volume and larger weight.
difference
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rechargeable battery
Disposable batteries are commonly referred to as "disposable" batteries, because they cannot be recharged and used after being exhausted, so they can only be discarded.Common disposable batteries includeAlkaline manganese battery, zinc manganese battery, lithium battery, silver zinc batteryZinc air battery, zinc mercury battery and magnesium manganese battery.
Rechargeable batteries are commonly lead-acid batteries, nickel cadmium batteriesFerronickel batteryNickel hydrogen battery, lithium ion battery.Its advantage is long cycle life. They can be fully charged and discharged for more than 200 times. Some rechargeable batteries have higher load capacity than most disposable batteries.In the use of ordinary nickel cadmium and nickel hydrogen batteries, the unique memory effect causes inconvenience in use and often causes premature failure.
Ordinary batteries are disposable, while rechargeable batteries can be charged with a charger and used repeatedly.
The nominal voltage of ordinary single batteries 1, 2, 3, 5 and 7 is 1.5V, while the nominal voltage of nickel hydrogen and nickel cadmium rechargeable batteries is 1.2V, that of lithium ion rechargeable batteries is 3.7V, and that of lead-acid batteries is 12V.
Terminology
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rechargeable battery
Charging rate
（C-rate)
C is the first letter of Capacity, which is used to indicate the current value during battery charging and discharging.
For example, when the rated capacity of the rechargeable battery is 1000mAh, it means that the discharge time can last for 1 hour at 1000mAh (1C), such as 200mA (0.2C)dischargeThe time can last for 5 hours, and charging can also be calculated according to this comparison.
Termination voltage
rechargeable battery
When the battery is discharged, the voltage drops to the lowest point where it is not suitable to continue dischargingworking voltage Value.
According to different battery types and different discharge conditions, the terminal voltage of battery discharge is also different.The specified termination voltage generally decreases with the increase of discharge current.Take 1.2V, 800mah nickel hydrogen battery as an example, take 40ma (20 hour rate) discharge current and its discharge end voltage is generally set at 1.15v;If the discharge current of 80ma (10 hour rate) is adopted, its discharge termination voltage will be set at 1.10v.
Open circuit voltage
When the battery is not discharged, the potential difference between the two poles of the battery is calledopen circuitVoltage.
The open circuit voltage of the battery will depend on the positivenegative poleDifferent from the electrolyte material, if the positive and negative materials of the battery are exactly the same, the open circuit voltage of the battery will be the same no matter how large the volume of the battery and how the geometric structure changes.
Discharge depth
During the use of the battery, the percentage of the capacity released by the battery in its rated capacity is calledDischarge depth。
The depth of discharge has a deep relationship with the charging life of the secondary battery. The deeper the discharge depth of the secondary battery is, the shorter its charging life will be. Therefore, deep discharge should be avoided as far as possible during use.
Over discharge
In the discharge process, if the battery exceeds the terminal voltage of battery discharge and continues to discharge, the internal pressure of the battery may rise, the reversibility of positive and negative active substances will be damaged, and the capacity of the battery will be significantly reduced.
Overcharge
rechargeable battery
During the charging process, the voltage of the battery will gradually increase with the increase of the stored energy. When the stored energy of the battery reaches saturation and the electrode material cannot continue to charge, if the battery continues to charge, the electrolyte will start electrolysis, and oxygen will be generated at the anode and hydrogen will be generated at the cathode. This will cause an internal pressure rise in the sealed battery and damage the internal structure of the battery,This phenomenon is called overcharging.
In order to avoid damage to overcharged batteries, the capacity of the cathode is usually larger than that of the anode, so that when overcharged, the anode will first reach saturation and produce oxygen, while the cathode is not saturated and will not produce hydrogen, and the oxygen generated by the anode will react chemically with the metal cadmium generated by charging to absorb oxygen after diffusion to the cathode,And the reaction speed is balanced with the speed of metal cadmium production, so the pressure rise of the battery can be effectively avoided.However, if the charging current is too large (when fast charging is used), the balance will be lost. If the internal pressure of the battery is too high, the safety valve of the battery will be pushed open, and hydrogen and oxygen will leak to the outside of the battery. The battery will not be sealed again until the pressure decreases and the safety valve is closed.However, the leakage of gas has reduced the internal chemical materials and shortened the battery life.
energy density
The electric energy released by the average unit volume or mass of the battery.
Generally, under the same volumeenergy density It is 2.5 times of that of nickel cadmium battery and 1.8 times of that of nickel hydrogen batteryBattery capacityIn the same case, lithium-ion batteries will be smaller and lighter than nickel cadmium and nickel hydrogen batteries.
Self discharge
No matter whether the battery is used or not, its power loss will be caused due to various reasons.
If it is calculated in one month, lithium ion batterySelf dischargeAbout 1% - 2%, Ni MH battery self discharge about 3% - 5%.
cycle life
The capacity of rechargeable battery will gradually decrease to 60% - 80% of the initial capacity after repeated charging and discharging.
memory effect
In the process of battery charging and discharging, many small bubbles will be generated on the battery plate. After a long time, these bubbles will reduce the area of the battery plate and indirectly affect the battery capacity.
maintain
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The charging problem of rechargeable batteries has always been the focus of attention. Correct and good charging methods can ensure the life of batteries.There are various charging methods recommended for rechargeable batteries. Different charging methods have different requirements for the charger circuit, which naturally affects the cost.
Figure 1
Memory effect is one of the natural enemies of rechargeable batteries. It is generally believed that it is caused by long-term incorrect charging, which can cause premature aging of batteries.The memory effect can make the battery unable to be charged effectively, and the phenomenon that once charged, it will be full, and once used, it will be finished.The way to prevent the memory effect of the battery is to ensure the principle of "sufficient discharge" of the battery, that is, it is better to discharge the residual power in the battery before charging, and it should be sufficient at one time during charging.Usually, nickel cadmium batteries are prone to memory effects, so special attention should be paid when charging. In theory, nickel hydrogen batteries have no memory effects, but it is better to follow the principle of "sufficient lighting", which is why many chargers provide additional discharge functions.For batteries whose capacity decreases due to memory effects, we can use the method of sufficient lighting at one time and lighting at one time for several times, and most of the batteries can be repaired.For some batteries that have been shelved for a long time and lost their activity, try to use the method of high current shock to try to inactivate them.
The relationship between the battery charging time and the charging current is that the battery capacity is divided by the charging current to get the charging time. Considering the loss in the charging process, the calculated charging time is multiplied by the constant 1.2.
The most commonly used simple charging method for nickel cadmium and nickel hydrogen batteries is to use 10% C constant current charging, also known as "slow charging", that is, determine the charging current according to 10% of the current capacity value. For example, for a battery with a nominal capacity of 500mAH, its recommended charging current is 50MA;Another example is a battery with a nominal capacity of 1300mAH, whose recommended charging current is 130MA.It can be regarded as fully charged after 12-15 hours of continuous charging under this current.Although it is recommended to use constant current charging, the requirements are not strict, and the current can fluctuate greatly, so theChargerThe structure is very simple. Generally, only one transformer, diode for rectification, resistor for current limiting, LED and other indicating devices are needed to convert 220V mains power into appropriate low voltage. The cost is very low. Most independent conventional chargers on the market use this method, but their shapes are different.Although "slow charging" is relatively simple, it takes more than ten hours to recharge, which is really a bit impatient.The battery manufacturer also allows users to charge the battery with 30% C current for 4-5 hours when they need it urgently, which is called "fast charging". However, it is not recommended to use it frequently, which theoretically causes slight damage to the battery.Therefore, most conventional chargers have two levels of "fast charging" and "slow charging", and users are recommended to use "slow charging".
Figure 2
In many cases, users need to charge the battery quickly, effectively and safely, and fast charging requires a large current.In the process of high current charging, the battery will appear polarization effect, which will make the battery hot. When the high current charging battery is fully charged, if it is not stopped in time, the battery will quickly heat up, which can lead to battery burning and explosion in serious cases.Therefore, the fast charger is required to have the function of full automatic stop, and also to solve the polarization effect to make charging efficient and safe.Early fast chargers used simple timing charging, but such chargers were highly targeted and the charging effect was not satisfactory.Modern chargers use special charging control IC toPulsating currentCharge the battery to solve the polarization effect, accurately judge whether the battery is full by detecting the battery - Δ V, and provide protection measures such as temperature protection and additional functions such as discharge.However, this kind of charger is complex in structure and high in cost. It is generally used for mobile phones, walkie talkies and other high-end communication equipment and appliances.
There are many rechargeable battery models in the marketBattery No.5For example, the capacity includes 500MAH, 600MAH, 700MAH, 850MHA, 1200MAH, 1300MAH, etc.From the above 10% C "slow charging" principle, we can understand that batteries with different capacities need different charging currents. Some universal chargers on the market are mostly designed for early 500MAH and 600MAH batteries. The charging current is between 60-70mA. It takes longer to charge batteries with larger capacity.The specific time can be used firstA multimeterMeasure the actual charging current, and then divide the battery capacity by the charging current times the coefficient 1.2 to get the charging time.For Ni MH batteries charged with more than 1000mAH, you can try to use the fast charging gear of the common charger. Because this gear has a large current, use a multimeter to measure the actual charging current. If the value is close to the charging current of 10% C required for the Ni MH battery charged, it is just wrong.In fact, many so-called NiMH battery chargers on the market are just conventional chargers with higher charging current.
There are mainly two types of chargers sold on the market, namely, special charger and universal charger.The so-called special type is used to charge with a certain electrical integrated battery block, typically a charger for mobile phones.This type of charger is generally suitable for the original supporting products. First, the charging voltage corresponds to the model (there is a special charging adapter). Second, most of these chargers use an efficient fast charging mode with high efficiency.The biggest advantage of domestic compatible special chargers is that they are cheap. However, because different manufacturers have different internal circuits and different charging methods, many products use simple electronic circuits to reduce costs. The charging effect is poor and the internationally recommended charging methods are not used.If you buy a domestic charger, you should not choose a product that is too cheap. It is better to have a discharge and full stop product.There is no shortage of high-quality products in domestic products, which are generally equipped withliquid crystalCharging process indication and automatic fast charging function.Universal chargers need to charge batteries independently. The products on the market are mainly made in China. Most of them use the 10% C simple charging circuit mentioned above, and some have additional functions such as power test.When purchasing a universal charger, pay attention to matching with the battery you use (take slow charging as an example, that is, the charging current is 10% C). Some of the market prices are slightly more expensive, and some of them have fast chargers that can be fully charged and stop automatically, which is more convenient to use.All mid-range universal fast chargers are equipped with charging status indication, and the product packaging specification indicates that they have the function of full automatic stop.
When several batteries work together, if there is a large difference between them, the use effect and life will be adversely affected, so please ensure the consistency of the batteries in the same working group, that is, ensure their specificity. For a large number of batteries, it is necessary to number the batteries properly. For example, for batteries used in digital cameras, please keep several batteries charged together,When using electricity together, don't use several batteries as batteries for electric toys or alarm clocks, or put them back into digital cameras. No matter what kind of rechargeable batteries are, they actually have memory effects, but lithium batteries and nickel metal hydride batteries are relatively mild, so we should follow a principle that they should be recycled in a fully depleted and fully charged manner, so that the memory effect can be minimized,To keep the battery performance in the best state, it is better to conduct several deep discharges on the rechargeable battery every year and a half to reduce the lattice phenomenon of the battery contents, but this requires more strict control, which is not to discharge the battery voltage to zero, or just short circuit. More relevant knowledge and equipment are required. For nickel hydrogen batteries and lithium batteries, the memory effect is slight,At ordinary times, there is no need to discharge.
During the charging process, the battery should not be interrupted. After charging for a period of time, do not unplug the charger plug for some reason, and then recharge it after a while. In fact, if the battery is not charged, it has begun to discharge itself, which is not in accordance with the principle of full depletion. It is not good for the battery. If the battery needs to be stored for a long time, please fully charge it first, so as to avoid a long time later,The battery is over discharged due to the self discharge of the battery. For newly purchased batteries, the manufacturer has charged them well, and they can be used according to the principle of fully exhausted 2 and fully charged.
exception handling
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1. Charger smoking: quickly pull out the charger and take out the battery.Charger smoke is generally caused by burning out the transformer due to high mains voltage;
2. The battery is hot (the outer package will crack if it is serious): take out the battery quickly and cover it with a hard box for 1 hour to prevent possible danger.The battery burning is generally caused by the short circuit of the battery or the internal abnormality of the battery. At this time, check whether the charger circuit is normal, and check whether the battery voltage is abnormal (the heating of the charging battery during charging is a normal phenomenon);
3．Battery leakage: Take out the battery quickly, cover it with a hard box for about 1 hour to prevent possible danger, and then wipe the charger clean;
4. Rechargeable battery cannot be used after leakage;
5. Unable to charge: check the charger and battery.At this time, the product should be sent to the supplier's after-sales service department for treatment, and the charger and battery should not be disassembled without permission.
matters needing attention
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1. Carefully read the battery manual, use the recommended battery, and operate according to the operating procedures;
2. Check whether the contacts of electrical appliances and batteries are clean, wipe them with wet cloth if necessary, and install them in the correct polarity direction after drying;
3. Children should not be allowed to replace batteries without adult supervision. Small batteries such as AAA should be kept away from children;
4. Do not mix new and old batteries or batteries of different models, especially dry batteries and rechargeable batteries;
5. Do not attempt to regenerate the primary battery by heating, charging or other methods to avoid danger;
6. Do not short circuit the rechargeable battery, or it will damage the battery and heat the battery to burn.
7. Do not heat the battery or throw the battery into water or fire. Putting the battery into water will cause the battery to fail. Putting the battery into fire will cause the battery to break, or
The violent chemical reaction bursts and injures people, or produces some harmful gases and smoke.
8. Do not disassemble the battery or try to penetrate the battery with sharp tools, because the electrolyte inside the battery will hurt skin and clothing.
9. Disconnect the power switch after using the electrical appliance to avoid fire due to heating;
10. The battery should be taken out of the electrical appliances that have not been used for a long time, and stored after being emptied.Take it out for charging and discharging every 3 months or so;
11. The battery shall be stored in a cool and dry place, avoiding direct sunlight;
12. Nickel charger and lithium charger cannot be mixed;
13. Do not use the battery by welding. The high temperature generated during welding will damage the internal structure of the battery, which may make the battery unusable or even dangerous;
14. Reverse charging is not allowed. Reverse charging is equivalent to over discharge. Over discharge will cause adverse reactions inside the battery and lead to serious damage to the battery
The amount of gas is likely to cause chemical leakage of the rechargeable battery.
15. Do not put the rechargeable battery under the rain.Rainwater can conduct electricity. When the battery is placed under the rain, it is likely to have a short circuit, causing the battery to discharge due to instantaneous high current
If it gets hot, it will damage the battery or cause danger.
16. The battery cannot be stored in a high temperature or high humidity environment, which will aggravate the reaction of the battery itself, so it is unable to provide sufficient capacity for consumers.In addition,
Under high temperature and humidity, the aging speed of the battery will also be greatly accelerated, and the electronic components will also be corroded (except for high-temperature batteries).
17. Do not insert the positive and negative poles of the battery reversely, or the battery will swell or break;
18. When the battery is stored, it is better not to mix it with metal objects, and the insulating film wrapped outside should not be torn off at will.[1]
choose
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The most versatile are No. 5 (AA) and No. 7 (AAA) rechargeable batteries. Many digital cameras, Diskman, Walkman, MD, PDA, etc. need to use them.This type of battery mainly includes nickel cadmium/nickel hydrogen. The following is about nickel cadmium/nickel hydrogen.Nickel cadmium/nickel metal hydride batteries have AA and AAA models that can directly replace ordinary disposable batteries 5 and 7. Although the standard voltage of ordinary batteries is 1.5V while that of nickel cadmium/nickel metal hydride batteries is only 1.2V, it generally does not affect the use.
First of all, let's introduce an important parameter of rechargeable battery - battery capacity, expressed in AH (ampere hour).We can see that it is a composite unit, which is composed of the product of current unit and time unit, representing the product of the continuous discharge time of the battery under constant current.In small batteries, we usually use a smaller unit, mAH (milliampere hour).For example, an ideal fully charged battery can be discharged for 10 hours with 60MA current. Multiplying the discharge current and time, we can know that the capacity of this battery is 600mAH. Theoretically, if it is used for 600MA discharge, it can be used for one hour (divide the discharge current by the battery capacity).The battery capacity parameter represents the amount of power that can be stored in the battery. In the same volume, more is always better. Generally, we can see the capacity label on the batteries in retail packaging.
The capacity, specification and price are the main considerations for purchasing such rechargeable batteries.First, determine the specifications of the batteries to be purchased. For equipment with a narrow battery compartment or devices that need to place multiple batteries side by side, pay attention to whether it is appropriate to purchase batteries with high capacity and large diameter.Rechargeablepositive electrodeThere are also two different forms. One is similar to ordinary batteries with some protrusions, which help to contact the battery box or other negative electrodes well, and the other is a flat battery cap, which is more suitable for welding into battery blocks.It is recommended to generally use the former form of rechargeable battery.The rechargeable batteries on the packaging are divided into industrial packaging and retail packaging. The industrial packaging only uses single color plastic skin. The main supplier is the battery block. There is no other information on the single battery except the production date.The appearance of retail packaging is quite beautiful, with detailed information including brand, trademark, capacity and place of origin. Some also have simple charging methods, suitable for ordinary users.The second isBattery capacitySelection of.For digital cameras, flash lights, communication equipment and other equipment that consume large amounts of electricity, from the perspective of working time and performance, high-capacity nickel metal hydride batteries are the first choice. The batteries with large capacity can be used for a longer time after being sufficient once.Battery No.5It can reach 1200-1300mAH,7 # batteryIt can reach 550mAH, almost twice the low capacity nickel cadmium battery.For radios with low power consumption, nickel cadmium batteries are more economical.The third is the choice of brands. Generally, famous brand products have guaranteed quality and excellent performance. Panasonic, Sanyo and Toshiba batteries are used in many cell phones and interphones.Among the retail NiMH batteries, GP Super Mac is more famous, as well as the combination packaging of chargers.The domestic swan brand is also good.GP, Hitachi and Panasonic are more common in nickel cadmium batteries, and their performance is also good.
The rechargeable batteries of famous brands are severely counterfeited. There are a large number of counterfeit batteries of various famous brands in the electronic market. The price is extremely low, so you should not have any illusions about the performance.For example, the famous GP super battery, counterfeit products and even the hanging plate packaging are completely copied.Therefore, you should be careful to distinguish the true from the false when you buy it. You can buy it in a large photographic equipment store. Although the price is slightly higher, it is not easy to buy fake goods.
Development prospect
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1. The policy benefits the new energy vehicle industry and drives the development of power lithium battery industry
China has issued a number of new energy vehicle incentive policies, clearly supporting the development of new energy vehicles, upgrading the new energy vehicle industry to the focus of government industry support for development during the "14th Five Year Plan", bearing the important mission of China's automobile industry to achieve "overtaking at a curve".At present, China has established a relatively complete policy support system for the new energy vehicle industry from research and development, production, purchase, use to infrastructure, which is conducive to the further development of the new energy vehicle industry.
At the same time, more and more cities, such as Beijing, Shanghai, Guangzhou, Shenzhen, Tianjin, Hangzhou and other first tier and second tier cities, have begun to restrict the purchase and traffic of traditional fuel passenger vehicles in response to the environmental pollution caused by the automobile industry, which also helps to increase the demand for new energy vehicles.
2. "Replacing oil with electricity" has promoted the market demand of power lithium battery industry
China's natural resources are rich in coal, poor in oil and gas, and its dependence on crude oil is high.Reducing the fuel consumption of motor vehicles and maintaining the national energy security are the hard constraints for the development of the automobile industry. In addition to the developed power industry in China, "replacing oil with electricity" is the long-term trend of the development of the automobile industry.
In recent years, with the depletion of oil resources, various countries have issued fuel vehicle sales prohibition schedules.Under the domestic environment of double credit policy and traffic restriction in major cities, new energy vehicles have become the main trend of future global automobile market development.As the core component of new energy vehicles, the market demand of power lithium battery is bound to grow rapidly.
3. Improve environmental protection requirements and accelerate industry development
With the rapid development of China's economy and the continuous increase of car ownership, the environmental pollution problem has become increasingly prominent, and the demand for new clean energy has become increasingly urgent.The environmental problems caused by the exhaust gas from traditional vehicles directly aggravate people's desire for the application of new energy.
The development of new energy automobile industry based on low pollution and low emissions through technological innovation, industrial transformation, new energy development and other means is an important way to achieve sustainable economic development.In terms of market demand for lithium batteries, the field of power batteries for new energy vehicles is undoubtedly a growth point with great potential.[4]
Characteristic use
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Figure 3
Nickel cadmium: small capacity with memory effect Nickel hydrogen: small capacity with memory effect.
Lithium ion: no memory effect, thin body and large capacity. Due to different electrode materials, the electromotive force is 3V or 3.6V.Lithium battery is currently the largest battery in the same volume, and is widely used in digital cameras, laptops, mobile phones and other electronic products.
Lead storage: electromotive force is about 12V,Lead storage batteryIt can be recharged repeatedly. The electrolyte is sulfuric acid solution,internal resistanceIt is small and widely used in automobiles and motorcycles.
Iron lithium: more sufficient power, safer, lighter, futureElectric vehicleThe main direction of development.
Generally, the larger the capacity, the greater the quality of the same type of rechargeable battery.
Identification method
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According to IEC standard, the identification of nickel cadmium nickel hydrogen battery consists of five parts
2. The size data of the battery includes the diameter of the round battery, the height, the width, and the thickness of the square battery. The values are separated by a slash. Unit: mm
3. The discharge characteristic symbol L indicates that the appropriate discharge current ratio is within 0.5C
M indicates that the appropriate discharge current multiplier is within 0.5-3.5C
H indicates that the appropriate discharge current multiplier is within 3.5-7.0C
X indicates that the battery can work under 7C-15C high rate discharge current
4. High temperature battery symbol is represented by T
5. The battery connection piece represents CF represents no connection piece HH represents the connection piece for the pull type series connection piece of the battery HB represents the connection piece for the parallel series connection of the battery
For example, HF18/07/49 means that the square nickel metal hydride battery is 18mm wide, 7mm thick and 49mm high
KRMT33/62HH indicates that the discharge rate of nickel cadmium battery is between 0.5C-3.5. High temperature series single battery has no connector, diameter of 33mm, height of 62mm. According to IEC61960 standard, the identification of secondary lithium battery is as follows:
1. The battery identification consists of 3 letters followed by 5 numbers cylindrical or 6 square numbers
2. The first letter represents theNegative materialI represents lithium ion with built-in battery L represents lithium metal electrode or lithium alloy electrode
3. The second letter represents the positive material of the battery, C, cobalt based electrode, N, nickel based electrode, M, manganese based electrode, V, vanadium based electrode
4. The third letter represents the shape of the battery R represents the cylindrical battery L represents the square battery
5. Five numbers of digital cylindrical battery respectively represent the diameter and height of the battery. The unit of diameter is millimeter. The unit of height is one tenth of a millimeter. The diameter or height. When any size is greater than or equal to 100mm, a diagonal line should be added between the two sizes. Six numbers of the battery respectively represent the thickness, width and height of the battery. The unit of the three sizes is millimeter. When any size is greater than or equal to 100mm, the size should be between the two sizesIf any of the three dimensions is less than 1mm, the letter t shall be added before the dimension. The unit of this dimension is one tenth of a millimeter.[2]
working principle
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Figure 4
First, let's talk about the discharge process of the battery. The battery is a device that converts chemical energy into electrical energy.With zinc and copperPrimary batteryBattery is
Charging process
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Charging is to reverse the discharge process above
Take lead battery as an example:
Lead acid battery is the first practical battery manufactured.The principle is as follows:
Insert two lead plates A and B into the sulfuric acid solution. As a result of the action of lead in sulfuric acid, lead sulfate is formed on two lead plates A and B, and the solution is also saturated with lead sulfate. This is because there is no potential. When charging the battery, the chemical reactions on the two poles are as follows:
A;PbSO4+2H2O - 2e-→PbO2+H2SO4+2H+;
B:PbSO4+2e-→Pb+SO42-;
It can be seen that after charging, PbO2 on board A becomes positive, and Pb on board B becomesnegative pole。When discharging, the reactions of the two poles are as follows:
Positive pole: PbO2+H2SO4+2H+- 2e - → PbSO4+2H2O-2e -;
Negative pole: Pb+SO42 - → PbSO4+2e -;
The reaction during discharge is just the reverse process of charging.When charging, the highestemfIt is 2.2V.When discharging, the electromotive force gradually decreases, and it must be charged when it reaches 1.8V, otherwise the electrode plate will be damaged
New battery
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European and American countries have begun to develop a new rechargeable battery, called nickel zinc AA battery (Ni Zn battery)
Nickel zinc AA battery: the battery size is the same asni-mh /Dimensions of nickel cadmium: IEC specifications
The charger shall be able to charge 4 AA batteries at the same time
1.1. Constant current charge at C rate ( 1.5 amps ) until cell voltage reaches 1.9 volts/cell
Before the voltage of each battery reaches 1.9V, 1.5amps constant current charging
1.2. Maintain 1.9 volts/cell and terminate constant current and allow current to taper at constant float voltage ( 1.9 volt) condition.
Stop constant current charging when the voltage reaches 1.9V, and gradually reduce the current at 1.9V,
1.3. When taper current reach C/15,100 ma or when total time charge reaches 2.5 hrs terminate charge.
WhenSmall currentStop charging when C/15100mA is reached or the total charging time reaches 2.5 hours
Please review this charging information and give me any recommendations you may have to reduce cost and improve reliability.[3]
New generation battery
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Figure 5
Integrating rechargeable batteries and charging devices has become the development trend of new generation rechargeable battery design.USB battery The standard USB interface is built into the rechargeable battery, which is convenient to use and will become the future
Six myths
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Myth 1: Activation of new battery
Figure 6
The new battery should be charged and discharged circularly to activate its performance.
truth:To be precise, the above statement is not a rumor.There is a time difference between the battery delivery and the user's hands, ranging from one month to half a year.For batteries with a long time difference, their electrode materials will be passivated. Therefore, the manufacturer recommends that the batteries used for the first time should be fully charged and discharged for 3-5 times to eliminate the passivation of electrode materials and reach the maximum capacity.But usually, manufacturers do not pay attention to remind consumers that what is said here is completeCharge and dischargeIt should not be a deep discharge, but should be controlled at 5%~8%.Otherwise, a new battery is likely to be scrapped.
Myth 2: "the first three times" charging
When a piece of newBatteryAfter the purchase, it is better to conduct three cycles of charging and discharging. The charging time should exceed 12 hours in order to activate the maximum efficiency of the battery.
Truth: NiMH batteryIn order to achieve the most perfect saturation state, it needs to go through the process of "supplement" and "trickle", which usually takes about 5 hours.At present, the "constant current" and "constant voltage" charging characteristics of lithium ion batteries control their deep charging time within 4 hours.Once fully charged, the protection circuit inside the battery will automatically stop charging, so this practice is unscientific and has no practical significance.
Someone has done experiments with mobile phones.After charging the battery with the travel charger, switch to the seat charger to confirm the saturation degree of the battery.When he finds that the battery is still charged by the seat charger, he thinks that the battery has not reached saturation
。In fact, this test method lacks rigor.The reason is that the indicator light of the seat charge charger is not the only standard to detect whether it is really saturated or not. The reference voltage of the seat charge charger is not necessarily equal to the reference voltage of the mobile phone. Therefore, when the mobile phone thinks that the battery has reached the saturation state, the seat charge charger may not think so and still charge, but only it knows whether to charge it.
Myth 3: Best State
As long as the rechargeable battery is used properly, it will be in the best state within a certain cycle range and reach the maximum capacity.
For example, early nickel hydrogen and nickel cadmium batteries, if properly used and regularly maintained, will reach their maximum capacity in 10~200 cycle points (the capacity of nickel hydrogen batteries with factory capacity of 1000mAh may reach 1100mAh after 100 cycles).
truth:This statement is common in Japanese batteries, and can be seen in the cycle characteristic diagram in the technical specifications.However, for the current mainstream lithium-ion batteries, this cycle peak phenomenon does not exist.Since the capacity of lithium-ion batteries is less than one cycle at a time from delivery to scrap, there has never been a capacity recovery.Maybe some friends will askThinkPad NotebookThe user can recover the battery capacity through deep discharge.In fact, it is just the error detection of the test software, and the actual capacity of the battery has not been improved at all.
Is the lithium-ion battery in the best condition?The answer is yes, which is related to the change of ambient temperature.In general, lithium-ion batteries will show excellent performance at 25 ℃~40 ℃.At low or high temperature, its performance will be greatly reduced.For example, if you use a laptop in the direct sunlight outside, you will not use it indoors for a long time.
Myth 4: The higher the capacity, the better
For two batteries with the same nominal capacity (for example, 800mAh), if one of them actually measured 860mAh and the other 805mAh, then 860mAH must be better than 805mAh.
truth:Generally speaking, lithium ion batteries of different models (different volumes) have higher capacity and longer service life.If the factors such as volume and weight are not considered, the higher the capacity, the better.However, it may not be necessary for two batteries with the same nominal capacity (such as the above example).For the battery with high actual capacity, it is likely that the material used to increase the initial capacity is added to the electrode material, reducing the material used to stabilize the electrode.The result is that after dozens of cycles, the one with high capacity decays rapidly, while the one with low capacity is still strong.In order to reduce costs and expand sales, many domestic manufacturers often use this method to produce high-capacity batteries.After six months of use, users will find that the working time is greatly shortened.In short, the cost of improving the capacity is to sacrifice the cycle life. It is impossible to really improve the battery capacity without the manufacturer's concern about the battery materials
Myth 5: Battery preservation
If the rechargeable battery is not used, it should be discharged before storage.
truth:In fact, not only the rumors mentioned above, but also the fact that the lithium-ion battery should be fully or completely preserved will definitely confuse many people?The answer to this question should start from its congenital defect, that is, the "aging effect".After being stored for a period of time, part of the capacity of lithium ion batteries will be permanently lost even if they are not recycled. This is because the positive and negative electrode materials of lithium ion batteries have begun their depletion process since they left the factory.The aging amplitude is different under different temperatures and saturation degrees, and the specific amplitude is shown in the table.
It can be seen that the higher the storage temperature and the fuller the battery, the greater the capacity.Therefore, for long-term storage of lithium-ion batteries, users should control their power at 40% and store them at 15 ℃ or even lower.As for those Ni MH and Ni Cd batteries, this "aging effect" does not exist. After long-term storage, only a few full charges and discharges can restore their original capacity.
Myth 6: Charging after charging
When charging the battery, charge it for 12 hours after charging, which will help to increase the saturation of the battery.
truth:In general, a qualified seat charge charger will automatically close the charging circuit after charging, and there is no current. Even if the battery is placed on the seat charge for 10 hours, it will not help.At present, most mobile phone chargers sample such designs.Therefore, when the green indicator light is on, the battery can be taken down directly for use.[1]
