What kind of battery core should be used for the outdoor power supply?
Just as when buying a car, one considers the engine. When buying a power source, the main consideration is also the battery. The battery is the power storage part of the battery. The quality of the battery directly determines the quality of the battery, and the quality of the battery determines the quality of the power supply. It is also a guarantee of safety. The cell can realize over-current protection, over-charge protection, over-discharge protection, short-circuit protection, over-power protection, over-temperature protection, etc. Good batteries have a long life, stable performance, and safety.
Today we understand the difference between the following three types of batteries: lithium iron phosphate batteries, polymer lithium batteries, and ternary lithium batteries. The battery life, charging and discharging of electric vehicles, and all applications of outdoor power sources are also inextricably linked with the functions of the battery. The most commonly used on the market are lithium iron phosphate batteries, polymer lithium batteries, and ternary lithium batteries. The three batteries have their own characteristics.
The difference between lithium iron phosphate battery, polymer lithium battery, and ternary lithium battery
1. Polymer lithium battery
Polymer lithium batteries generally refer to polymer lithium ion batteries. The positive and negative materials used in polymer lithium batteries are the same as the liquid lithium ion. The positive materials are divided into lithium cobalt oxide, lithium manganate, ternary materials, and lithium iron phosphate materials. The negative electrode is graphite, and the operating principle of the battery is also the same. . The principle of polymer lithium battery is the same as that of liquid lithium. The main difference is that the electrolyte is different from liquid lithium. The primary structure of a battery includes three elements: a positive electrode, the negative electrode, and electrolyte. The so-called polymer lithium-ion battery means that at least one or more of these three primary structures use polymer materials as the primary battery system. In the polymer lithium-ion battery system developed now, polymer materials are primarily used in the positive electrode and electrolyte.
Advantages of polymer lithium battery
1) The operating voltage of a single battery is as high as 3.6v~3.8v, which is much higher than the 1.2V voltage of nickel-hydrogen and nickel-cadmium batteries.
2) The capacity density is large, and its capacity density is 1.5~2.5 times that of nickel-hydrogen battery or nickel-cadmium battery, perhaps higher.
3) The self-discharge is small, and its capacity is very small after being left for a long time.
4) Long lifespan, its cycle life can reach more than 500 times in normal use.
5) There is no memory effect, no need to empty the remaining power before charging, which is convenient to use.
6) The safety function is good. The polymer lithium battery adopts aluminum-plastic soft packaging in the structure, which is different from the metal shell of the liquid battery. Once a safety hazard occurs, the liquid battery is easy to burst, and the polymer battery will only blow up at best.
7) The thickness is small, and it can be made thinner. Ultra-thin, the battery can be assembled into a credit card. Ordinary liquid lithium batteries use the method of customizing the shell first and then plugging the positive and negative materials. The thickness is below 3.6mm and there is a technical bottleneck. Polymer batteries do not have this problem. The thickness can be below 1mm, which is in line with the current mobile phone needs.
8) Lightweight, the battery using polymer electrolyte does not need a metal shell as protective outer packaging. The weight of the polymer battery is 40% lighter than the standard steel shell lithium battery of the same capacity, and 20% lighter than the aluminum shell battery.
9) Large capacity, polymer battery is 10-15% higher than the steel shell battery of the same standard, and 5-10% higher than the aluminum shell battery. It has become the first choice for color screen mobile phones and MMS mobile phones. Most MMS mobile phones also use polymer batteries.
10) Small internal resistance
The internal resistance of polymer batteries is smaller than that of ordinary liquid batteries. Now the internal resistance of domestic polymer batteries can even be below 35mΩ, which greatly reduces the self-consumption of the battery and prolongs the standby time of the mobile phone. Level in line with international standards. This kind of polymer lithium battery that supports a large discharge current is an ideal choice for remote control models and has become the most promising product to replace nickel-hydrogen batteries.
11) The shape can be customized
The manufacturer is not limited to the standard shape, it can be economically made into a suitable size. The polymer lithium battery can add or reduce the thickness of the battery cell according to the needs of customers, and develop new battery cell types. The price is cheap, the mold opening cycle is short, and some can even be tailored to the shape of the mobile phone to make full use of the battery shell space and improve battery capacity.
12) Brief protection board planning
Due to the choice of polymer materials, the battery core does not catch fire or burst, and the battery itself has satisfactory safety. Therefore, the protection circuit planning of polymer batteries can consider saving PTC and fuses and then saving battery costs.
2. Lithium iron phosphate battery
Lithium iron phosphate battery refers to a lithium ion battery that uses lithium iron phosphate as the positive electrode material. The cathode materials of lithium batteries mainly include lithium cobalt oxide, lithium manganate, lithium nickelate, ternary materials, lithium iron phosphate, and so on. Among them, lithium cobalt oxide is the cathode material used by most lithium-ion batteries. Regarding the cathode materials of LiFePO4, the sources of the materials are relatively extensive, the cycle life is longer, the safety index is also high, and the environmental pollution is small, and it has a very strong generalization function in many cathode materials.
When the LiFePO4 lithium iron phosphate battery is charged, the lithium ion Li in the positive electrode moves to the negative electrode through the polymer separator; during the discharge process, the lithium ion Li in the negative electrode moves to the positive electrode through the separator. Lithium ion batteries are named after lithium ions move back and forth during charging and discharging.
Advantages of lithium iron phosphate batteries
1) The lithium iron phosphate battery has a long life, with a cycle life of more than 2000 times. Under the same conditions, lithium iron phosphate batteries can be used for 7 to 8 years.
2) Safe to use. Lithium iron phosphate batteries have undergone strict safety inspections and will not explode even in traffic accidents.
3) Fast charging. Using a dedicated charger, the battery can be fully charged after 40 minutes of charging at 1.5C.
4) The lithium iron phosphate battery is resistant to high temperatures, and the hot air value of the lithium iron phosphate battery can reach 350 to 500 degrees Celsius.
5) The lithium iron phosphate battery has a large capacity.
6) The lithium iron phosphate battery has no memory effect.
7) Lithium iron phosphate battery is environmentally friendly, non-toxic, non-polluting, with a wide range of original materials and low price.
3, ternary lithium battery
Ternary lithium battery refers to a lithium battery that uses lithium nickel cobalt manganese oxide as the positive electrode material and graphite as the negative electrode material. Unlike lithium iron phosphate, the ternary lithium battery has a high voltage path, which means that the specific energy and specific power of the ternary lithium battery are greater under the same volume or weight. In addition, ternary lithium batteries also have great advantages in terms of high-rate charging and low-temperature resistance. Compared with lithium iron phosphate batteries, ternary lithium batteries are more accustomed to current and future household electric vehicles.
Ternary lithium batteries have better low-temperature resistance and are the primary technical route for manufacturing low-temperature lithium batteries. At minus 20°C, ternary lithium batteries can release 70.14% of the capacity, while lithium iron phosphate batteries can only release 54.94% of the capacity. And because under low-temperature conditions, the discharge path of the ternary lithium battery is much higher than the voltage path of the lithium iron phosphate battery, and it starts faster.
The lithium iron phosphate battery is better than the ternary lithium battery. The theoretical life of the ternary lithium battery is 2000 times, but when it reaches 1000 cycles, the capacity decays to 60%; even the best brand in the industry, Tesla, has passed 3000 cycles. It can only hold 70% of the power at a time, and the lithium iron phosphate battery has 80% of the capacity after the same cycle.
The above is the difference between lithium iron phosphate battery, polymer lithium battery, and ternary lithium battery. As to which battery to choose, you need to compare it yourself and select the appropriate lithium battery according to the actual situation.
