Exploring the lithium plating phenomenon in lithium batteries: The key to safeguarding battery safety and performance.

Hey, friends! Do you know what the core energy source is in the electronic devices we can't live without every day, such as mobile phones and laptops? That's right, it's lithium batteries. But do you understand a somewhat troublesome phenomenon in lithium batteries - lithium plating? Today, let's deeply explore the lithium plating phenomenon in lithium batteries, understand what it is all about, what impacts it brings, and how we can deal with it.

I. What is lithium plating in lithium batteries?

Lithium plating in lithium batteries is like a "little accident" in the battery world. Simply put, under specific circumstances, lithium ions in the battery should settle down well at the negative electrode, but instead, they mischievously precipitate on the surface of the negative electrode and turn into metallic lithium, just like growing small branches. We call this lithium dendrite. This phenomenon usually occurs in low-temperature environments or when the battery is repeatedly charged and discharged. Because at this time, the lithium ions running out from the positive electrode cannot be normally inserted into the negative electrode and can only "set up camp" on the surface of the negative electrode.

II. Why does lithium plating occur?

The lithium plating phenomenon doesn't appear for no reason. It's caused by many factors working together.

First, if the "small house" of the negative electrode is not large enough, that is, the negative electrode capacity is insufficient to accommodate all the lithium ions running from the positive electrode, then the excess lithium ions can only precipitate on the surface of the negative electrode.

Second, be careful when charging! If charging at low temperatures, with a large current, or overcharging, it's like having too many guests coming to the "small house" of the negative electrode all at once. It can't handle it, and the lithium ions cannot be inserted in time, so the lithium plating phenomenon occurs.

Also, if the internal structure of the battery is not designed reasonably, such as if there are wrinkles in the separator or the battery cell is deformed, it will affect the way home for lithium ions and make them unable to find the right direction, which can easily lead to lithium plating.

In addition, the electrolyte is like a "little guide" for lithium ions. If the amount of electrolyte is insufficient or the electrode plates are not fully infiltrated, the lithium ions will get lost, and lithium plating will follow.

Finally, the SEI film on the surface of the negative electrode is also very important! If it becomes too thick or is damaged, the lithium ions cannot enter the negative electrode, and the lithium plating phenomenon will appear.

III. How can we solve lithium plating?

Don't worry, we have ways to deal with lithium plating.

We can optimize the battery structure. For example, design the battery more reasonably, reduce the area called Overhang, use a multi-tab design, and adjust the N/P ratio to allow lithium ions to flow more smoothly.

Controlling the battery charging and discharging conditions is also crucial. It's like arranging appropriate "traffic rules" for lithium ions. Control the charging and discharging voltage, current, and temperature so that the lithium plating reaction is less likely to occur.

Improving the composition of the electrolyte is also good. We can add lithium salts, additives, or co-solvents to make the electrolyte better. It can not only inhibit the decomposition of the electrolyte but also prevent the lithium plating reaction.

We can also modify the negative electrode material. It's like putting a "protective clothing" on the negative electrode. Through methods such as surface coating, doping, or alloying, we can improve the stability and anti-lithium plating ability of the negative electrode.

Of course, the battery management system is also essential. It is like a smart "butler" that monitors and intelligently controls the charging and discharging process in real time to ensure that the battery works under safe conditions, avoid overcharging and discharging, and reduce the risk of lithium plating.

IV. What impacts does lithium plating have on batteries?

Lithium plating is not a good thing! It will cause lithium dendrites to grow inside the battery. These lithium dendrites are like little troublemakers. They may penetrate the separator and cause an internal short circuit, which is very dangerous. Maybe it will even trigger thermal runaway and safety accidents. Moreover, during the lithium plating process, the number of lithium ions decreases, and the battery capacity will also decline, shortening the battery's service life.

V. What is the relationship between low-temperature environments and lithium plating?

In low-temperature environments, the electrolyte will become sticky. Lithium precipitation at the negative electrode will be more severe, the charge transfer impedance will increase, and the kinetic conditions will also deteriorate. These factors combined are like adding fuel to the lithium plating phenomenon, making lithium batteries more prone to lithium plating in low-temperature environments and affecting the immediate performance and long-term health of the battery.

VI. How can the battery management system reduce lithium plating?

The battery management system is very powerful! It can monitor battery parameters in real time, just like a pair of keen eyes, always observing the battery's situation. Then adjust the charging strategy according to the data to make the lithium ions obedient.

It can also identify abnormal changes in the battery charging curve. Like a smart detective, it can predict the lithium plating phenomenon in advance and avoid it.

Thermal management is also very important! The battery management system can heat or cool the battery to control the operating temperature and allow lithium ions to move at an appropriate temperature to reduce the risk of lithium plating.

Balanced charging is also essential. It can ensure that each single battery in the battery pack is charged evenly, just like allowing each lithium ion to find its own "small room".

Moreover, through advances in materials science, we can also optimize the negative electrode material and structural design of the battery to make the battery stronger.

Finally, adjusting the charging rate and current distribution is also crucial. Avoid excessive local current density and set a reasonable charging cut-off voltage to allow lithium ions to be safely inserted into the negative electrode.

In conclusion, although the lithium plating phenomenon in lithium batteries is a bit troublesome, as long as we deeply understand its causes and take effective preventive and control measures, we can make lithium batteries safer, have better performance, and have a longer service life. Let's work together to protect our lithium batteries!