It is generally known that there are two types of mobile power batteries: one is 18650 lithium ion battery, and the other is lithium ion polymer battery. High-quality mobile power supplies use lithium-ion polymer batteries as batteries. However, general users have very little specific knowledge of lithium ion polymers. This article explains in detail the lithium ion polymer battery from the structure and performance, advantages, classification and development direction. Generally, the main structure includes three elements: positive electrode, negative electrode and electrolyte. The so-called polymer battery is a battery system in which at least one or more of these three items use polymer materials as its main substrate, and lithium ion polymer batteries are packaged in flexible packaging (aluminum foil)
Structure and performance of lithium ion polymer battery
Lithium polymer battery is mainly composed of positive electrode, negative electrode and separator paper. In the lithium polymer batteries currently being developed, polymer materials are mainly used in positive electrodes and electrolytes. The materials of the positive electrode include conductive polymers, organic sulfur compounds, or inorganic compounds commonly used in lithium ion secondary batteries. The electrolyte can use solid or colloidal polymer electrolytes, or organic electrolytes. The negative electrode usually adopts metal or carbon intercalation compound. Comparing lithium polymer batteries with lithium ion batteries currently on the market, there is still considerable room for development of lithium polymer batteries in terms of shape, charge and discharge, reliability and environmental issues. In terms of shape, Keng polymer battery has many advantages such as thinning, arbitrarily area and arbitrarily shaped, so it can be made into batteries of any shape and capacity according to product requirements.
Shenzhen Sunhe Energy Technology Co., Ltd.Technical experts pointed out that in terms of charge and discharge characteristics, because lithium polymer batteries can use polymer cathode materials and metal anodes, their weight energy density will be more than that of current lithium electronic secondary batteries. In terms of reliability characteristics, because the electrolyte of the polymer lithium secondary battery uses polymer materials, there will be no safety concerns such as leakage, combustion and explosion. At present, many manufacturers have launched commercialized polymer lithium secondary batteries, and the emphasis is on their ultra-thin characteristics. Generally speaking, the thickness of the polymer battery is about one, which can be reduced by at least about 50% compared with the minimum thickness of the current lithium-ion secondary battery, so it can provide manufacturers with considerable flexibility when designing products.
Advantages of lithium ion polymer battery
1. Good safety performance. The polymer lithium battery uses aluminum-plastic soft packaging in structure, which is different from the metal shell of the liquid battery. Once a safety hazard occurs, the liquid battery is easy to explode, while the polymer battery will only blow up.
2. The thickness is small and can be made thinner. Ordinary liquid lithium batteries use the method of customizing the shell first, and then plugging the positive and negative materials. The thickness of the battery is below 3.6mm and there is a technical bottleneck. The polymer cell does not have this problem. The thickness can be below 1mm, which meets the needs of current mobile phones. direction.
3. Light weight. The weight of a polymer battery is 40% lighter than a steel shell lithium battery of the same capacity and 20% lighter than an aluminum shell battery.
4. Large capacity. Polymer batteries have a capacity of 10-15% higher than steel shell batteries of the same size and 5-10% higher than aluminum shell batteries. They have become the first choice for color screen mobile phones and MMS mobile phones. Nowadays, most of the new color screen and MMS mobile phones on the market also use Polymer batteries.
5. Small internal resistance. The internal resistance of polymer batteries is smaller than that of ordinary liquid batteries. At present, the internal resistance of polymer batteries is lower than that of ordinary liquid batteries. The internal resistance of the polymer batteries is greatly reduced. It can even achieve the self-consumption of 35m battery and extend the standby time of mobile phones. Reach the level of keeping up with international standards. This kind of polymer lithium battery that supports large discharge current is an ideal choice for remote control models, and becomes the most promising product to replace Ni-MH batteries.
6. The shape can be customized. The polymer battery can increase or decrease the thickness of the battery cell according to the needs of customers, and develop new battery cell models, which are cheap and short in mold opening cycle. Some can even be tailored to the shape of the mobile phone to make full use of the battery shell space and improve the battery. capacity.
7. Good discharge characteristics. Polymer batteries use gel electrolyte, compared to liquid electrolysis. The colloidal electrolyte has stable discharge characteristics and a higher discharge platform.
8. The design of the protection board is simple. Due to the use of polymer materials, the battery core does not fire or explode, and the battery itself has sufficient safety. Therefore, the protection circuit design of polymer batteries can consider omitting PTC and fuses to save battery costs.