How do rechargeable batteries, charge and discharge cycles work
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2022/07/23 17:27:25
Batteries store electrical energy in the form of chemical energy, which can be converted into electrical energy. The process by which chemical energy is converted into electrical energy is called discharge. A chemical reaction during the discharge causes electrons to flow through an external load attached to the terminal, causing the electrons to flow in the opposite direction of the current.
Some batteries can return these electrons to the same electron by applying a reverse current, a process called charging. Batteries that can recover electrons at the same electrode are called rechargeable; if they cannot do so, they are called non-rechargeable.
In a battery, the electrode where reduction occurs is called the cathode and the electrode where oxidation occurs is called the anode.
Lithium-ion batteries This type of battery has a discharge/charge cycle of about 400-1200 cycles. It depends on various factors, how you charge or discharge the battery.
The lithium-ion battery is rated at 3.60 V. When the battery is fully charged, the voltage is about 4.2V, and when the battery is fully discharged, the voltage is about 3.0V. Lithium-ion batteries come in different sizes and shapes, and their capacity is also available on demand.
Discharge of lithium ion batteries
During battery discharge, the load is connected to the terminal battery. Lithium ions are released from the negative electrode into the electrolyte. This lithium ion is absorbed by the positive electrode. The negative electrode also releases electrons that pass through the external wire to the positive electrode. This supplies current to our circuit.
(Lithium ion battery discharge)
Lic6 * * * * * * * C6 + Li + E - at the negative electrode
Coo_2 + Li + E - * * * * & GT; Reaction on positive electrode of licoo_2
Total reaction LiC6 + COO_2 * * * * * C6 + LiCoO2
Lithium-ion batteries can discharge at a rate of 10C (where C is the capacity of the battery). If your battery can provide 1000mah, then the discharge rate will be 10 x 1000 = 10000mAh.
Lithium ion battery charging
When the lithium-ion battery is charged, the battery is connected to the charger. The positive electrode loses a negatively charged electron. To maintain a charge balance on the negative electrode, an equal amount of positively charged ions is dissolved into the electrolyte solution. These lithium ions move to the positive electrode, where they are absorbed by graphite. This absorption reaction also deposits electrons onto the graphite anode to "bind" the lithium ions.
Lithium ion battery charging
* * * * * * * * * * * Reaction on coo_2 + Li + E - positive electrode
C6 + Li + + E - * * * * & GT; Reaction on lic6 negative electrode
Full reaction; LiC6 + CoO2
Lithium ion battery charging chemistry uses constant current and constant voltage algorithms, which can be divided into four parts.
Charge :- When the battery is deeply discharged, the charge of each battery is less than 3.0V. The maximum constant current used to charge the battery is 0.1 degrees Celsius, which is called trickle charge.
Constant current :- When the voltage is higher than 3.0V per cell, constant current is applied in the range of 0.2C to 1c for constant current charging.
Constant voltage :- When the voltage reaches 4.2V per cell constant current charge. Constant voltage until the battery current drops to zero, which maximizes battery performance.
End of charge :- End of charge detection algorithm, detection current range down to 0.02c to 0.07C or use timer method. It detects when a constant voltage phase starts it terminates the charger 2 hours after the constant voltage phase.
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