1. Basic Working Principle of Lithium-ion Batteries:

Lithium-ion batteries store and release energy by shuttling lithium ions between the positive and negative electrodes. During charging, external power drives lithium ions from the positive electrode to the negative electrode, where they are stored in the negative electrode material. During discharging, lithium ions are released from the negative electrode and return to the positive electrode, releasing energy along the way to power devices.

2. Voltage variation:

At the beginning of charging, the voltage is slightly low due to the influence of battery internal resistance and polarization effect. As the charging progresses, the internal chemical reactions of the battery gradually reach equilibrium, and the voltage gradually rises until it reaches the charging limit.

Taking ternary lithium batteries as an example, their charging process can be divided into four stages: trickle charging (low-voltage pre charging), constant current charging, constant voltage charging, and charging termination.

In the trickle stage, if the battery voltage is lower than 3V, it will be preheated at one tenth of the preset current, and the voltage will slowly rise; Once the voltage jumps above the trickle threshold, it enters constant current fast charging, where the current increases and the voltage rises accordingly. Typically, the voltage of a single battery is set between 3.0 and 4.2V during this stage; When the voltage reaches 4.2V, the constant current stage ends and switches to constant voltage charging. The voltage remains constant at 4.2V while the current gradually decreases; Until the current drops to one tenth of the preset current, the charging is successfully completed. During the discharge process, the voltage trend is opposite to that of charging. At the beginning, the voltage rises high and gradually decreases with the consumption of lithium ions and internal resistance until it reaches the lower limit of discharge.

3. Reasons for voltage fluctuations:

Battery internal resistance: During charging and discharging, the battery exhibits a certain internal resistance, resulting in voltage loss.

Polarization phenomenon: Uneven distribution of surface charges on the electrode causes voltage fluctuations.

Chemical reaction kinetics: The internal reaction rate of the battery affects the rate of voltage change, and the voltage fluctuates between fast and slow.

During the charging and discharging process of lithium-ion batteries, the voltage may vary due to factors such as internal resistance, polarization effects, and chemical reaction kinetics. This change is a normal part of battery operation and an important indicator for evaluating battery performance and health status.

4. What is the impact of voltage changes on the performance of lithium-ion batteries

Relationship between voltage and capacity:

As the voltage increases, the battery capacity also increases, the energy storage capacity is enhanced, and the usage time is extended.

Relationship between voltage and discharge curve:

The discharge curve reflects the variation of voltage over time, and voltage differences cause changes in the shape and slope of the curve, which is crucial for equipment use and power display.

Relationship between voltage and charging/discharging speed:

High voltage accelerates the charging and discharging process, but attention should be paid to the risk of overheating and a balance should be sought between performance and safety.

Relationship between voltage and safety:

Overcharging and over discharging of lithium-ion batteries can affect their safety performance and even cause serious accidents such as fires. The voltage limitation of batteries is one of the important factors to consider when designing charging control circuits to ensure the safe use of batteries. When the battery voltage exceeds the normal range, it may trigger the battery's protection mechanism, such as power-off or short-circuit protection, to prevent battery damage or safety accidents.

The voltage variation of lithium-ion batteries has a significant impact on their performance. Therefore, when selecting and using lithium-ion batteries, it is necessary to fully consider the voltage factor and choose the appropriate battery type and specifications based on actual needs and application scenarios. Meanwhile, attention should also be paid to the voltage status of the battery during use to ensure its safety and stability.

Battery safety guarantee

The rise of power battery systems has provided powerful power sources for modern transportation and energy storage, but it also comes with some potential dangers. Explosion proof valves, as critical safety devices, play an irreplaceable role in preventing dangerous events caused by internal short circuits in batteries.

The birth of explosion-proof valves

In order to avoid potential disasters caused by internal short circuits in batteries, engineers have introduced explosion-proof valves as part of the power battery system. The basic working principle of an explosion-proof valve is to quickly release energy when energy is concentrated and explodes, in order to prevent the battery pack from exploding.

The working principle of explosion-proof valve - rapid energy release

The core function of an explosion-proof valve is to quickly release the energy inside the battery to the outside in the event of a dangerous event such as a short circuit inside the battery. This is achieved through a valve mechanism, which typically consists of a combustible gas release valve and a combustible gas storage unit.

When a short circuit occurs inside the battery, the temperature rises sharply, causing the combustible gas inside the storage unit to rapidly heat up and expand. Once the gas reaches a certain pressure, the combustible gas release valve will open, releasing the gas into the external environment. This process is very rapid and can quickly transfer energy before potential dangers become serious.

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