You can make your own cell phone battery (I tried it), but the process is a bit tedious. Here's how to make your own cell phone battery: (Click the reference link, there are specific drawings, but. you need to pay attention to safety)
1. Battery: 18650 lithium battery is recommended, with a single capacity of 2200-2400mA. It is usually available at computer stores or computer repair shops. -35 yuan. It is difficult to tin the lithium battery due to electric shock, and it also encounters high heat which can easily damage the internal protection circuit. It is best to ask the tradesman to do parallel spot welding (two sections in parallel). during the purchase.
2. Remove the lithium battery part of the discarded 680 cell phone battery and keep the parte circuit.
3. Wiring
4. Charging: You can directly use a mobile phone charger (egg charger), as long as the positive and negative poles are correctly connected, you can connect them. with an alligator clip, two sections. Charging together may take a long time (professional lithium battery chargers are available, but the quality and price are not satisfactory).
5. What I have to say: It is recommended to use the original charger. If you are using a home charger, it is best to use a multimeter to measure the cut-off voltage if it is higher. greater than 4.2 V is dangerous. (Lithium batteries will explode if overcharged!! Really!!) If you have strong practical skills, you can create a homemade protection circuit or charger.
How batteries are made
Process
According to professionnels, the process of making fake cell phone batteries is very simple. The most important thing is to find a suitable size battery cell, then put the battery cell into the original battery box and connect the wires, then use a soldering iron to connect the wires, and a battery is ready.
4 photos in total
Homemade cell phone battery
Charging
Basic charging of a cell phone battery homemade is quite simple, but the safety of charging is the most important difficulty. The rule of thumb is to charge at a constant current (between 0.2 C and 0.7 C) until the battery reaches 4.2 Vpc (volts per cell), and maintain the voltage of 4.2 V until the charging current drops to 10% of the original charging value. . The maximum charging voltage (maximum charging voltage) and the termination current (termination currentn) vary slightly depending on the battery manufacturer.
Protection
Charging temperature: When lower than 0 degree and higher than 45 degree C, charging will not be possible. The charging current should not be too high, generally less than. 0.7C;
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Discharge protection: to avoid danger caused by battery short circuit;?
Charging voltage: built-in permanent fuse to prevent excessive voltage from being applied to the battery;
Overload protection: When the battery voltage exceeds 4.3V, it stops charging;
Overcharge Protection: When the battery voltage is lower than 2.3V, it will stop discharging (the voltage value varies depending on the manufacturer), when the pool has been exposed to an environment exceeding 100 degrees C, the fuse will open.
Standard specifications
The “Current general specificationss for China's lithium-ion batteries for mobile phones clearly stipulate that mobile phone batteries sold in the domestic market must undergo strict testing and have reached the standard, the surface of the battery is marked with the name of the product, capacity, place of origin, model, implementation standards, precautions and plates, etc. The mobile phone batteries manufactured by us that appear on the market obviously do not meet national standards and should be resolutely investigated and sanctioned.
Problem
Cause
According to battery sellers, there was a large market for on-site battery production in 2009, and most products were sold to migrant workers in cities. Manufacturers that supply battery equipment said cell phone upgrades are too fast, leading to incapabilityability to supply batteries to the subsequent market. As long as you buy a microcomputer spot welding machine and a set of battery cells, you can make different types of batteries. on the site.
The quality is concerning
Batteries produced in this way have not been tested for safety. Not only can the quality not be guaranteed, but they are also unsafe to use. Due to power outages, leaks and heat. In the event of overcharging, overdischarging, etc., the separator of the lower battery cell may be broken, causing a short circuit between the positive and negative electrodes of the cell. the battery could explode.
Lithium-ion (Li-ion) batteries are developed from lithium batteries.
Lithium-ion battery composition:
(1) Upper and lower battery covers
(2) Positive electrode - the materialthe active material is lithium cobalt oxide
(3) Separator - a special composite membrane
(4) Negative electrode - the active material is carbon
(5) Organic electrolyte
(6) Battery case (divided into steel case and aluminum case)
3. What are the advantages of lithium-ion batteries ion? What are the disadvantages ?
Lithium-ion batteries have the following advantages:
1) The working voltage of a single battery can reach 3.6-3.8V:
2) It has a high specific energy and can currently reach 100 to 115 Wh/kg and 240 to 253 Wh/L (2 times that of Nl-Cd, 1.5 times that of Ni-MH). technology, the specific energy can reach 150 Wh/kg and 400 Wh/L
3) Long lifespan, generally more than 500 times, even 1,000 times for low discharge electrical appliances fluent. , the battery life will double the competitiveness of the electrical appliance.
4) Good safety performance, no pollution and no memory effect As the predecessor of Li-ion, lithium batteries easily form dendrites. and cause short circuits, which reduces their areas of application: Li-ion does not contain cadmium, lead or mercury. Environmental pollutants: Ni-Cd batteries with certain processes (such as sintering) have them. One of the major disadvantages of Li-ion is the “memory effect”, which seriously restricts the use of batteries, but Li-ion doesn't have this problem at all.