+86 18988945661 
contact@iflowpower.com 
+86 18988945661
Language
+86 18988945661 contact@iflowpower.com +86 18988945661
Author ：Iflowpower – Portable Power Station Supplier
First of all, you have to know, the mobile phone is a lithium-ion battery. Yes, this year's lithium-ion battery has been obtained this year. The lithium ion battery is tightly consists of a positive electrode (anodeelectrode), an electrode, an electrolyte, a separator, a housing (Case).
Because the space inside the phone is small, in order to fully utilize space, the lithium-ion battery on the phone is lithium cobaltate (high compact density, smaller volume, less local), and negative is graphite. The principle of lithium-ion batteries believe that everyone has been understood, which depends on the migration of lithium ions between the positive electrode and the negative electrode to store and release energy. The migration behavior of lithium ions is like rocking chairs, and it is called a rocker battery.
When charging, the lithium ion is disengaged from the positive electrode, and the electrolyte is then embedded in the graphite layer of the negative electrode, and the electron combined with the outer circuit; when discharge, the direction of movement of lithium ions and electrons is opposite to charging. When discharged, the lithium ion moves from the negative electrode to the positive electrode, first in the graphite layer, through the interface of the graphite and the electrolyte, then migrate in the electrolyte, by the electrolyte and the lithium cobalt-cobalt acid, last in lithium cobalt acid Disaster. This step, it can really be said to be across the mountains and the sea, and the lithium ions move home is really not easy.
It is naturally its coordinate axis. The abscissa is the capacity Q (electricity), the ordinate is the voltage U See this, can't help but think of a formula: w = qu (energy = power×Voltage) utilizes a little bit of calculus knowledge, it can be understood that the area of the curve and the coordinate axis is energy. This picture tells us that the lithium-ion battery has decreased with the temperature, but it is not only that, its capacity is reduced, the voltage is low.
This is why lithium-ion batteries are not durable in winter. The little cuteness of the curious heart is certainly not satisfied with just understanding this phenomenon, and I want to know the deep origin of the inside. As mentioned earlier, when the lithium-ion battery is discharged, the lithium ions move from graphite to the positive electrode, and to span the mountains and the sea.
When the temperature of the lithium ion battery is lowered, the migration of lithium ions will be more difficult. When the temperature is lowered, the diffusion coefficient of lithium ions in graphite and lithium cobaltate will decrease, and the viscosity of the electrolyte increases, the migration of lithium ions in the active substance and the electrolyte are greatly obstructed. This sounds less intuitive, let's take a look at the ingredients that have no electrolyte, know what is going on.
The solvent of the electrolyte is a mixture of carbonate (EC) and diomethane (DMC). Ethylenecarbonate, melting point: 34 ~ 37 ° C carbonate dimethylcarbonate, melting point: 2 ~ 4 ° C see the melting point of these two substances? The vinyl carbonate is solidified at room temperature, and dimethyl carbonate is solid at 0 ° C. Then when the lithium-ion battery is in a low temperature environment, the viscosity of the electrolyte is increased, and even partially solidified.
Lithium ions are migrated in the refrigerated electrolyte, think it is very difficult to think about it. At low temperatures, the migration of lithium ions is hindered, the most significant impact is that the internal resistance of the battery increases, the end voltage of the lithium-ion battery (end voltage = open circuit voltage - current×Battery internal resistance decline, when the mobile phone tests to the lithium-ion battery, think that the battery is fast, and reminds you that the battery is insufficient, even in order to protect the battery, will automatically shut down. In fact, the lithium-ion battery is clearly that there is so much power, but it will not play it.
In order to overcome this problem, scientists are also working hard to develop electrolyte additives and low temperature electrolyte, allowing lithium-ion batteries to use it under low temperatures. Then there is a lithium-ion battery on the phone, is there a way to let it fall in winter? Of course, you don't have a warm place in the cold outdoor mobile phone. For example, in the warm room, keep your small phone does not play small temper.
Say, do you play with your mobile phone in a warm room? If it is really necessary to use mobile phones in cold outdoors, then you will use it, and quickly take it. In case the phone is frozen, don't worry, put it in a warm place to recover, and use it normally. It is indeed that winter should pay attention to it is not to charge the phone at a low temperature.
As mentioned earlutation, the migration rate of lithium ions at low temperatures will be lowered, and when charging the lithium ion battery at low temperature, the rate of lithium ions embedded in the graphite layer is slow, and there will be lithium ions and are not embedded in the graphite layer, but straight The electron-forming metal lithium is obtained on the surface of the graphite. This process is called the lithium, and a portion of the precipitated metal lithium has become not active, that is, it will not participate in the subsequent lithium ion migration, becoming a dead lithium.
Copyright © 2024 iFlowpower - Guangong iFlowpower Technology Co., Ltd.
