1. Different sizes. Although the 18650 and No. 5 batteries look a little like each other, their sizes are actually different. The 18650 batteries are much larger in length and diameter than No. 5 batteries.
2. Different voltage. The voltage of lithium battery is generally about 3.5-4.0V, the most common is 3.7V, while the voltage of No. 5 battery is 1.5V (non-rechargeable) or 1.2V (rechargeable).
3. Its working principle (internal chemical reaction process) is different.
4.18650 is a rechargeable battery. Most of the ordinary No. 5 batteries are disposable batteries, but few can be recharged.
1. Voltage is different, capacity is different, the former can be charged, the latter can not be charged.
2. From the shape analysis: these two kinds of batteries are cylindrical batteries, but the shape specifications are different. The specifications of 18650 lithium batteries are 18mm in diameter and 65mm in length, while the rules of No. 5 batteries (actually the scientific name of No. 5 batteries is 1450 batteries) are 14mm in diameter and 50mm in length.
3. Analysis of types: 18650 lithium-ion batteries can be divided into 18650 lithium-ion batteries, 18650 lithium iron phosphate batteries and 18650 nickel-hydrogen batteries, while No. 5 batteries include nickel-hydrogen rechargeable batteries, nickel-cadmium rechargeable batteries, alkaline zinc-manganese batteries (abbreviated as "alkaline batteries"), ordinary acid zinc-manganese batteries (abbreviated as "ordinary
The so-called polymer lithium batteries refer to lithium-ion batteries using polymer as electrolyte, which can be divided into "semi-polymer" and "all-polymer". "Semi-polymer" refers to a layer of polymer (usually PVDF) coated on the isolation film, which makes the core more adhesive, the battery can be made harder, and its electrolyte is still liquid electrolyte. The "all polymer" refers to the use of polymers in the core to form a gel network, and then injected into the electrolyte to form electrolytes. Although "all polymer" batteries still use liquid electrolyte, the consumption is much less, which greatly improves the safety performance of lithium ion batteries. As far as I know, only SONY is producing "all polymer" lithium-ion batteries.
On the other hand, polymer batteries refer to lithium-ion batteries using aluminium-plastic packaging film as the outer packaging, which is commonly known as soft-packed batteries. The packaging film consists of three layers: PP layer, Al layer and nylon layer. Because PP and nylon are polymers, this kind of core is called polymer battery.
1. Lower price
2. Not customized
SONY has always wanted to make lithium-ion batteries like alkaline batteries, with certain industrial standards, like batteries No. 5 and No. 7, which are basically the same all over the world. But one of the great advantages of lithium-ion batteries is that they can be designed according to customers'needs, so there can not be a unified standard. So far, the lithium-ion batteries industry has basically only 18650, which is a standard model. The others are designed according to customers' needs.
3. Poor safety
We know that in extreme cases (such as overcharge, high temperature, etc.), the internal reactions of lithium-ion batteries will occur intensely, producing a large number of gases. 18650 batteries use metal shells with certain strength. When the internal pressure reaches a certain level, the steel shells will burst and explode, resulting in terrible safety accidents.
That's why rooms that test 18650 batteries generally have to be protected by layers, and must never be accessed during testing. Polymer batteries do not have this problem, even in extreme cases, because the packaging film strength is low, as long as the air pressure is slightly higher, it will burst, there will be no explosion, the worst case is combustion. Therefore, polymer batteries are superior to 18650 batteries in terms of safety.
4. Low energy density
The capacity of 18650 batteries can reach about 2200 mAh, so the energy density is about 500 Wh/L. At present, the mass production of polymer batteries can be close to 600 Wh/L.
But polymer batteries also have their own shortcomings. Mainly because of the high cost, because it can be designed according to customer needs, the R&D cost should be included. In addition, various shapes and types lead to non-standard fixtures in the manufacturing process, which increase the cost accordingly. Polymer batteries have poor versatility, which is also brought about by flexible design. It is often necessary to redesign one for customers in order to make a difference of 1 mm.
III. Application of 18650 Lithium Battery
The application of lithium secondary battery in energy battery industry benefits from its superior performance. With the continuous development of lithium secondary battery technology, it has been widely used in our daily life; rechargeable batteries used many times are more and more popular with consumers. Focus on the energy battery industry, fully understand the battery and then let us "use it for ourselves". At present, 18650 lithium batteries have certain applications in the following areas.
1. Energy Storage
Mainly used in base station power supply, clean energy storage, power grid energy storage, home optical storage system, etc.
It mainly refers to electric vehicles, electric bicycles, new energy vehicles and so on.
3. Digital Class
Mobile phones, tablets, laptops, electric toys, MP3/MP4, headphones, charging treasures, aeromodelling, mobile power supply, etc.
Lithium polymer battery refers to all solid state or gel too electrolyte for lithium-ion battery. Aluminum-plastic composite film is generally used as packaging material. There are only two real lithium polymer batteries in the world. One is SONY in Japan and the other is ATL in China.
Lithium batteries generally refer to aluminium-shell batteries with liquid electrolyte and aluminium shell as outer packaging materials.
Lithium polymer batteries are safer than lithium batteries. Lithium polymer batteries are upgrading products of lithium ion batteries. Compared with the current popular lithium-ion batteries, it has the advantages of large capacity, small size (thin), safety (no explosion). However, because the whole industry chain needs a certain time to replace, its cost (cost) is still relatively high, only used in high-end digital products (ultra-thin laptops, etc.).
It can be predicted that in the next 5 - 10 years, lithium polymer batteries will replace the existing lithium ion batteries! In fact, the penetration rate of lithium polymer batteries has reached a certain level in Japan, Korea and other countries where the electronic products industry is relatively developed, but our country is still relatively backward in this respect, let's wait and see! In the near future, mobile phones using lithium polymer batteries will be cheaper, so I must replace a safer mobile phone (battery)! __________
Lithium-polymer battery (Li-polymer, also known as polymer lithium battery): with many obvious advantages, such as high energy density, smaller size, ultra-thin, lightweight, high safety and low cost, it is a new type of battery. In shape, lithium polymer batteries are ultra-thin and can be made into batteries of any shape and capacity to meet the needs of various products. The minimum thickness of this kind of battery can be up to 0.5mm. Compared with lithium ion batteries, lithium polymer batteries have the following characteristics:
1. There is no leakage problem in the battery. There is no liquid electrolyte in the battery and colloidal solids are used.
2. Thin batteries can be made: with a capacity of 3.6V 400mAh, the thickness can be as thin as 0.5mm.
3. Batteries can be designed in many shapes.
4. Battery flexibility: The maximum flexibility of polymer batteries is about 90 degrees.
5. Can be made into a single high voltage: liquid electrolyte batteries can only be connected in series with several batteries to obtain high voltage, while polymer batteries can be made into a multi-layer combination in a single to achieve high voltage because they have no liquid.
6. The capacity of lithium-ion batteries will be twice that of lithium-ion batteries of the same size.