1. Charging process
Driven by an electric field, lithium ions are extracted from the positive electrode lattice, pass through the electrolyte, and are inserted into the negative electrode lattice.
At the start of charging, the voltage of the battery to be charged should be checked first. If the voltage is below 3V, pre-charging should be performed first, with the charging current being 1/10 of the set current, generally around 0.05C. After the voltage rises to 3V, the standard charging process begins. The standard charging process is as follows: constant current charging is performed at the set current. When the battery voltage rises to 4.20V, constant voltage charging is switched to maintain the charging voltage at 4.20V. At this time, the charging current gradually decreases. When the current drops to 1/10 of the set charging current, charging ends.
2. Discharge process
The process is exactly the opposite. Lithium ions return to the positive electrode, while electrons travel through the external circuit via electrical appliances to the positive electrode and recombine with lithium ions. When the battery discharges, electrons e from the negative electrode travel through the external circuit to the positive electrode, while positive lithium ions Li+ jump from the negative electrode into the electrolyte, crawl through the winding holes in the separator, swim to the positive electrode, and recombine with the electrons that have already arrived.
The higher the battery discharge current, the smaller the discharge capacity and the faster the voltage drops.
Lithium-ion battery pack assembly process:
Tools/Materials: Positive electrode material, negative electrode material, separator paper
Steps/Methods
Pulping:
Specialized solvents and binders are used to mix the powdered positive and negative electrode active materials separately. After being stirred at high speed until homogeneous, a slurry of positive and negative electrode materials is formed.
Coating:
The prepared slurry is evenly coated onto the surface of a metal foil, dried, and then used to make positive and negative electrode sheets.
assembly:
The positive electrode sheet, separator, negative electrode sheet, and separator are arranged in the order from top to bottom and wound to form the battery core. Then, the battery assembly process is completed by injecting electrolyte and sealing. The finished battery is then produced.
Formation:
The finished batteries are tested using specialized battery charging and discharging equipment. Each battery is inspected, and qualified finished batteries are selected for shipment.
1. The charging process of lithium-ion batteries
When a power source charges a battery, electrons e on the positive electrode travel through the external circuit to the negative electrode. Lithium ions Li+ jump from the positive electrode into the electrolyte, crawl through the winding holes in the separator, swim to the negative electrode, and combine with the electrons that have already arrived.
2. The discharge process of lithium-ion batteries
There are two types of discharge: constant current discharge and constant resistance discharge. Constant current discharge involves adding a variable resistor to the external circuit that changes with the voltage. Constant resistance discharge essentially involves adding a resistor between the positive and negative terminals of the battery to allow electrons to pass through. Therefore, as long as electrons on the negative terminal cannot move to the positive terminal, the battery will not discharge.
Electrons and Li+ move simultaneously, in the same direction but along different paths. During discharge, electrons travel from the negative electrode through the electronic conductor to the positive electrode, while lithium ions (Li+) jump from the negative electrode into the electrolyte, crawl through the winding holes in the membrane, swim to the positive electrode, and combine with the electrons that have already arrived.
Precautions for charging lithium-ion batteries
1. Beware of overheating during charging.
If the charging temperature exceeds the specified operating temperature (35°C), the lithium-ion battery's capacity will continuously decrease, meaning the power supply time when fully charged will be shortened, which will damage the battery quality and reduce its lifespan.
2. Be wary of excessively low temperatures during charging.
If the battery is charged in a low-temperature environment (below 4°C), the battery capacity will continue to decrease, and it may even fail to charge. However, the situation is different from that in a high-temperature environment. It is not a permanent damage. When the temperature rises to a suitable level, the battery capacity will return to its previous state.
3. Frequently used
Frequent use keeps electrons flowing inside lithium-ion batteries, which helps extend their lifespan. If you don't use them often, remember to complete a full charge cycle for the lithium-ion battery each month, i.e., a deep discharge and deep charge once.
The charging and discharging of lithium batteries occurs simultaneously with the movement of active lithium ions at the anode. In other words, during charging, active lithium ions are generated at both electrodes and move to the cathode, embedding themselves in its layered structure. The cathode is made of graphite, a layered carbon structure with numerous micropores. The more lithium ions embedded in these micropores, the higher the charging capacity.
Similarly, during battery discharge, lithium ions embedded in the carbon layer of the cathode are lost and move towards the anode. The more lithium ions return to the anode, the higher the discharge capacity. The capacity of a lithium battery that we usually refer to is its discharge capacity.
Recycling lithium batteries aligns better with the call for environmental protection and energy conservation, playing a more effective role in protecting the environment. Lithium batteries contain electrolytes, which can cause soil alkalization, and some highly acidic or alkaline components can also have adverse effects on nature. Therefore, the disposal of this product is of great importance. After processing, with continuous social development, lithium batteries are being recycled. This avoids causing particularly serious harm to the natural environment and offers a promising future for the further development of the lithium battery industry and this new industrial market. A certain processing model can both recycle the product and meet our pursuit of environmental protection and energy conservation.
Lithium battery charging method:
1. Charge appropriately.
Proper charging and discharging of lithium-ion batteries can extend their lifespan. Maintaining lithium-ion battery power between 10% and 90% helps protect the battery; it is not necessary to reach the maximum power level when charging batteries in digital products such as mobile phones and laptops.
2. Select a suitable charging temperature
Lithium battery charging temperature range: 0~45 degrees Celsius, lithium battery discharging temperature range: 0~60 degrees Celsius.
3. Avoid over-saturation
Lithium-ion batteries should be avoided from being charged during the charging process, as charging lithium-ion batteries in any form may cause serious damage to battery performance or even explosion.
4. There is no standard charging time for the first activation after drilling.
Lithium-ion and nickel-ion batteries have very different charge/discharge characteristics. Charging time must exceed 12 hours. Please repeat three times. Please charge according to the standard time and method. In particular, do not charge for more than 12 hours.
