18650 lithium-ion batteries can be divided into different types according to their appearance, performance and usage. So, what types of 18650 lithium-ion batteries are there? We'll take a look.
01According to appearance. According to the appearance of 18650 lithium ion batteries, they can be divided into the following two categories: cylindrical 18650 lithium ion batteries and square lithium ion batteries.
02According to outsourcing materials. According to the outer packaging materials of 18650 lithium ion batteries, we can divide 18650 lithium ion batteries into lithium batteries with steel casing, soft batteries and lithium batteries with aluminum casing.
03Depending on performance. According to the performance and usage of 18650 lithium ion batteries, we can divide 18650 lithium ion batteries into disposable lithium ion batteries, high rate lithium ion batteries and lithium ion batteries.high temperature thium-ion.
04Depending on the additives. According to the additives of 18650 lithium ion battery, that is, the materials of positive and negative electrodes, we can divide the 18650 lithium ion battery into lithium cobalt oxide battery, disposable manganese dioxide battery and lithium iron phosphate battery.
Lithium battery knowledge
Pacific Automotive Network distinguishes them by their shape, which can be divided into flexible batteries, cylindrical batteries and square batteries. shell batteries. Its rated voltage can reach 3.6-3.8V, with relatively high energy density, high voltage platform, high tap density, long cruise range, large output power, poor high temperature stability, but excellent low temperature performance and relatively high cost.
What is a ternary lithium battery? Full nameof a ternary lithium battery is "ternary material battery", which generally refers to the use of lithium nickel cobalt manganate (Li(NiCoMn)O2, NCM) or lithium nickel cobalt aluminate (NCA) Lithium batteries with ternary cathode materials use nickel salt, cobalt salt and manganese salt as three different component ratios and adjust them differently, so they are called "ternary" and include many types of batteries with different relationships. . Distinguished by their shape, they can be divided into soft batteries, cylindrical batteries and square hard-shell batteries. Its rated voltage can reach 3.6-3.8V, with relatively high energy density, high voltage platform, high tap density, long cruise range, large output power, poor high temperature stability, but excellent low temperature performancere and a relatively high cost.
Battery industry experts believe that blade batteries have five major advantages
1. According to the raw material standard system, the conceptual energy density can reach 350 watt hours per kilogram. has enormous development potential than lithium iron phosphate.important.
2. Volumetric energy density has been significantly improved. With the patented “blade battery” technology, the volumetric energy density of the PACK exceeds 330 watts per hour/L, which can be improved by 30% or more compared to the inherent battery system.
3. The cost is significantly reduced by 30% or more. By reasonably saving raw materials, labor costs, etc., the cost of batteries is expected to be significantly reduced by 30%.
4. Good heat dissipation performance. Since the "blade battery" is more fiOnly the traditional prismatic battery, the heat dissipation effect is stronger.
5. It offers a combination of high security unique cells, very safe and reliable. The difference between blade batteries and ternary lithium batteries is very obvious. The biggest advantage of lithium iron phosphate is safety, stability and cycle. The disadvantages of long life are poor low temperature performance and relatively low energy density. Ternary lithium batteries can achieve relatively high energy density, but have poor high temperature performance and slightly lower safety and stability than lithium iron phosphate. If the "blade battery" launched by BYD can really effectively solve the problem of energy density and its price is very competitive, it will still have great market potential.
(Images/texts/photos: Questions and answers from Pacific Automotive Network)
Lithium-ion batteries can only be charged and discharged 500 times?
I believe most consumers have heard that the lifespan of a lithium battery is “500 times”, 500 times of charging and discharging. After this number of times, the battery will “end its life”. in order to extend battery life If the battery is completely drained every time, does it really extend battery life? the answer is negative. The lifespan of a lithium battery is "500 times", which does not refer to the number of charges, but to one cycle of charging and discharging.
A charge cycle means that all of the battery's energy is used from full to empty, then charged from empty to full. This is not the same as a single charge. For example, a lithium battery only uses half its power the first day, then it is cfully charged. If it is still the same the next day, i.e. if you charge it half and charge it twice in total, this can only be counted as one charging cycle and not two. Therefore, multiple charges may often be required to complete a cycle. Each time a charge cycle is completed, the battery capacity decreases a little. However, this power reduction is very small. High quality batteries retain 80% of their original capacity after multiple charge cycles. Many lithium-ion powered products are still used as usual after two or three years. Of course, lithium batteries still need to be replaced once their lifespan is reached.
The so-called 500 times means that the manufacturer has achieved approximately 625 times of charging at a constant discharge depth (e.g. 80%), reaching 500 charge cycles.
(80%*625=500) (in ignorant factors such as reduction in lithium battery capacity)
Due to various influences in real life, especially the depth of discharge during charging is not constant, so 500 cycles of charging can only be used as a setting.Test battery life. Lithium batteries can generally be charged and discharged 300 to 500 times. It is better to partially discharge lithium batteries than to fully discharge them, and to avoid frequent full discharges. Once the battery leaves the production line, the clock starts ticking. Whether you use it or not, the lifespan of lithium batteries only lasts the first few years. The decrease in battery capacity is due to an increase in internal resistance caused by oxidation (which is the main cause of the decrease in battery capacity). Finally, the resistance of thecell reaches a point where, even though the battery is fully charged, it is unable to release stored energy.
The aging rate of lithium batteries is determined by temperature and state of charge. The table below illustrates the reduction in battery capacity for both settings.
Charging temperature 40% charging 100%
Capacity 0°C after one year Capacity 98% after one year Capacity 94%
Capacity 25°C after one year 96% Capacity 80% after one year
40°C Capacity 85% after one year Capacity 65% after one year
60°C Capacity 75% after one year Three months later Capacity 60%
As shown in the figure, a high state of charge and increased temperature accelerate the decline in battery capacity.
If possible, try to charge the battery to 40% and place it in a cool place. This allows the battery's own protection circuits to operate for a long life. If the beatterie is exposed to high temperatures after being fully charged, it will cause serious damage to the battery. (So when we use fixed power supply, the battery is fully charged and the temperature is usually between 25-30°C, which will damage the battery and cause its capacity to decrease).
Influence factor 1: Depth of discharge and recharge time
From the data on the left image obtained from the experiment, we can know that the recharge times are related to the depth of discharge. The greater the depth of discharge of the battery, the more rechargeable it can be, the less you need to recharge it.
The number of times recharged * depth of discharge = the total number of charging cycles completed, the higher the number of charging cycles completed, the longer the battery life, that is- i.e. the number of times rechargeable. * depth de discharge = actual battery life (ignoring other factors)
Influence factor 2: overcharge, overdischarge and large charge and discharge current
Avoid to overcharge the battery in any form. If the lithium-ion battery is overcharged, the battery will be seriously damaged and even explode.
Avoid deep discharge below 2V or 2.5V, as this may quickly and permanently damage the lithium-ion battery. Internal metal plating may occur, which may cause a short circuit and render the battery unusable or dangerous.
Most lithium-ion batteries have electronic circuits inside the battery that turn off if the battery voltage drops below 2.5 V, exceeds 4.3 V when charging or discharging, or if the battery current exceeds a predetermined threshold. the battery will be disconnected.
Avoid currentsheavy charging and discharging, which puts excessive pressure on the battery.
Influence factor 3: Overheated or undercooled environment
TemperatureThis also has a significant impact on the lifespan of lithium batteries. Below freezing environments can cause lithium batteries to deplete as soon as electronic products are turned on, while overheating environments will reduce battery capacity. Therefore, if the laptop uses an external power source for a long time without removing the battery, the battery will be exposed to the high heat emitted by the laptop for a long time and will soon be discarded.
Influence factor 4: Fully charged or discharged state for a long time
Excessively high and low power states have a negative impact on the life of lithium batteries . The nshadow of repeated charges shown on most electrical appliances or batteries sold is based on 80% discharge as a benchmark test. Experiments show that for some notebook lithium batteries, if the battery voltage often exceeds the standard voltage of 0.1 volt, that is, from 4.1 volts to 4.2 volts, the Battery life will be cut in half. If it increases by 0.1 volt, the battery life will be cut in half. lifespan will be reduced to 1/3; The more fully you charge the battery, the greater the battery loss will be. A long-term low or no power condition will increase the resistance to the movement of electrons inside the battery, resulting in a smaller battery capacity. It is best for lithium batteries to be in an intermediate state of charge, where they have the longest life.
From the above, nWe can summarize the following points which can extend the capacity and life of lithium batteries. If you use an external power supply to power your laptop for a long time, or if the battery charge exceeds 80%, remove the battery immediately. There is no need to fully charge the battery during normal charging, just charge it to around 80%. Adjust the operating system power options and set the power alarm above 20%. The minimum battery power should not be less than 20%. For mobile phones and other small electronic devices, you should unplug the power cord (including the USB interface for charging function) immediately after charging. Keeping it connected will damage the battery. Charge frequently, but it is not necessary to fully charge the battery. Whether it's a computerlaptop or mobile phone, be careful not to let the battery run out (automatic shutdown). If you're traveling, keep the battery fully charged, but continue to charge your devices whenever conditions permit. Use a smarter, more energy-efficient operating system. First, keeping lithium-ion batteries properly charged and discharged can extend battery life. Keeping the lithium-ion battery power between 10% and 90% is beneficial to protect the battery. This means that when charging batteries of digital products such as mobile phones and laptops, it is not necessary to reach the maximum value.
If digital products equipped with lithium-ion batteries are exposed to sunlight or stored in hot cars, it is best to keep these products turned off because if the operating temperature exceeds 60 degrees Celsius, the lithium-ion battery will accelerate aging.
Lithium battery charging temperature range: 0-45 degrees Celsius, lithium battery discharge temperature range 0-60 degrees Celsius.
Second, if the cell phone battery needs to be charged every day, the reason may be that the battery is defective or it is time to "retire".
For laptop owners, it is best to remove the battery if it is plugged in for a long time (the high heat generated by the computer while in use is not good for the battery of the laptop).
Third, generally, 50% battery is the most beneficial to lithium ion battery storage. 1. Primary lithium battery
Also called primary lithium battery. It can be discharged continuously or intermittently. Once the energy is exhausted, it can no longer bere used and it is widely used in low-power electronic products, such as cameras. Primary lithium batteries have a very low self-discharge and can be stored for 3 years. The effect will be better if stored in refrigerated conditions. It is a good idea to store primary lithium batteries in a low temperature location. Note: Primary lithium batteries are different from lithium-ion batteries, cannot be charged, and charging is very dangerous!
2. Lithium-ion battery
Also called secondary lithium battery. It can be stored for more than six months at 20°C because its self-discharge rate is very low and most of its capacity can be restored.
Lithium batteries have a self-discharge phenomenon. If the battery voltage is stored below 3.6V for a long time, the battery will discharge excessively.ent and will damage the internal structure of the battery, thereby reducing the battery capacity. life. Therefore, lithium batteries stored for a long time should be recharged every 3 to 6 months, that is, charged to a voltage of 3.8 to 3.9 V (the optimal storage voltage of batteries lithium is approximately 3.85 V) and maintained at a depth of discharge of 40% to 60%, should not be full. Batteries should be stored in a dry environment between 4°C and 35°C or in moisture-proof packaging. Keep away from heat sources and do not expose to direct sunlight.
Lithium batteries have a wide application temperature range. They can still be used outdoors during the northern winter, but their capacity will be significantly reduced if returned to room temperature, the capacity can be restored. For cylindrical lithium-ion batteries, the model number comusually has 5 digits. As shown in the table below. The first two numbers are the diameter of the battery and the middle two numbers are the height of the battery. The unit is millimeter. For example, the 18650 lithium battery has a diameter of 18 mm and a height of 65 mm. Model diameter (mm) Height (mm) abcde ab cd Conventional cylindrical lithium ion battery model table model rated capacity (mAh) rated voltage (V) end of discharge voltage (V) rated charging voltage (V) internal resistance (mΩ) diameter (mm) Height (mm) Reference mass (g) ICR18650 1800~2600 3.6-3.7 3.0 4.2 ≤70 18 65 45 ICR18490 1400 3.6-3.7 3.0 4.2 ≤70 18 49 34 ICR14650 1100 3.6-3.7 3.0 4.2 ≤80 14 65 27 ICR14500 800 3.6-3.7 3.0 4.2 ≤80 14 50 21 ICR14430 700 3.6-3.7 3.0 4.2 ≤80 14 43 18 js145007003.0V (used with lithium battery voltage regulator)3.04.2≤80145021 Cylindrical lithium ion battery model powertable model nominal capacity (mAh) nominal voltage (V) end of discharge voltage (V) nominal charge voltage (V) internal resistance (mΩ) diameter (mm) height (mm) Reference mass (g) INR18650 1200~1500 3.6 3.0 4.2 ≤60 18 65 45 INR18490 1100 3.6 3.0 4.2 ≤60 18 49 34 Cylindrical lithium iron phosphate lithium ion battery model table rated capacity (mAh) rated voltage ( V) discharge final voltage (V) Nominal charging voltage (V) Internal resistance (mΩ) Diameter (mm) Height (mm) Reference mass (g) IFR26650 3000 3.2 2.0 3.6 ≤80 26 65 94 IFR22650 1800 3.2 2.0 3.6 ≤80 22 65 67 IFR18650 1100 ~ 1400 3.2 2.0 3.6 ≤80 18 65 45 IFR18490 1000 3.2 2.0 3.6 ≤80 18 49 34 Note: Internal resistance ≤ mΩ means that when fully charged, constant current discharge is performed at the maximum discharge current when the internal resistance reaches this mΩ. , the battery is close to scrap metal
Lithium-ion batteries have different materialsials of positive electrode and different negative electrodes, so they have different operating voltages, such as 3.6 V or 3.7 V.
Rectangular lithium ion battery
Rectangular lithium ion battery is the most common lithium battery in life. It has many models and is widely used in MP3, MP4, mobile phones, models. aircraft and other products.
Prismatic lithium-ion batteries are divided into two types: metal shell packaging (silver-white hard shell) and aluminum plastic shell packaging (white-gray soft shell, which can be scratched with nails). Lithium-ion batteries or liquid lithium batteries are encapsulated in aluminum plastic shells and are polymer (polymer) lithium-ion batteries. It can be said that the chemical materials and electrochemical properties used in these two batteries are similar. Physical batteriesThey use certain colloidal substances to help battery plates adapt to or absorb electrolyte, thereby reducing the use of liquid electrolyte. Therefore, the battery packaging can be changed from a metal shell to an aluminum plastic shell.
The metal cased lithium battery case is the negative electrode, and the positive electrode is on the protrusion on one side of the battery; the positive and negative electrodes of the aluminum cast lithium battery are the negative electrode. two plates on one side of the battery, and the case is an insulator
For square lithium-ion batteries, the model number is usually 6 digits. As shown in the table below. The first two numbers are the battery thickness, to 1 decimal place; the middle two numbers are the width of the battery; the last two digits correspond to the longbattery life. The unit is millimeter. For example, lithium battery 606168 has a thickness of 6.0 mm, a width of 61 mm and a length of 68 mm. (Note: Due to the different packaging methods used by different battery manufacturers, the capacity of prismatic lithium-ion batteries of the same model varies within 300mAh)
The rated voltage of lithium-ion batteries prismatic ion is generally 3.6. ~3.7 V. The end of charge voltage is generally 4.2 V. Square lithium-ion battery model length (mm) width (mm) thickness (mm) rated voltage (V) rated charging voltage (V ) abcdef ef cd a.b 3.6～3.7 4.2