What is a Lithium-ion Battery?

Catalog

Ⅰ History of Lithium-Ion battery

In 1912 G.N. lewis coined the concept of Lithium-Ion battery; it was only feasible in the 1970s and the first commercially unchargeable lithium battery was installed. In the later 1980s, engineers attempted and partially succeeded in creating the first rechargeable battery using lithium as the anode material. During the charging phase, they did not see this form of lithium battery unstable and would build a short time inside the battery to raise the temperature and cause a thermal disturbance.

One of those lithium batteries in cell phones exploded in Japan in 1991 over the face of a man. It was only after this incident that Li-ion batteries were to be treated with strict care. The manufacturers then recalled a great deal of these types of batteries on the market concerning safety issues. Sony introduced the state-of-the-art Li-ion batteries later after much research, using new chemistry until now.

Ⅱ Chemistry and working of Lithium-Ion battery

The Lithium-Ion batteries use Lithium-ion to carry out the work, as the name clearly suggests. Lithium is a high energy density, very light-weight metal that allows the battery to be light and provides small shapes with high-current conditions. The higher the energy density the smaller the battery would be, the more energy density can be contained per unit battery volume. It cannot be used as an electrode directly in the batteries, despite the overwhelming properties of lithium metal, because lithium is very volatile due to its metallic nature. We, therefore, use lithium ions which but are not metallic, have more or less the same property as lithium metal and are comparatively more secure to use.

Lithium-ion battery structure

Normally, a Lithium Battery Anode is created of carbon, and the Cobalt oxide or other metal oxide is used to create the Cathode of the battery. The electrolyte which is used to link those two electrodes is a plain, lithium-ion salt solution. When the lithium ions are released, travel to the cathode and bombard it until it is positively charged. Now that the cathode is positive, negative electrons are drawn to the cathode. These electrons are driven by our circuit and hence the circuit is driven.

The exact opposite occurs while charging. The electrons migrate from the charges into the battery and the lithium ions thus pass to anode, thus reducing the positive charges of the cathode.

Ⅲ Advantages and disadvantages Lithium-ion battery

1.Lithium-ion battery advantages

The use of a battery li-ion cell provides many advantages. This increasingly uses the technology for a wide range of applications. Anything from small appliances to smartphones, tablets, cars, and a lot more.

High energy density: One of the key benefits of lithium-ion battery technology is the high energy density. Batteries with a much greater power density are still required for electronic equipment such as cell phones, which tend to run longer between charges and yet consume more power. There are also various power applications from electric tools to electric vehicles. Lithium-ion batteries have a slightly higher power capacity. Electric cars will require high-energy battery technology.

Self-discharge: The self-discharge rate is a concern for many rechargeable batteries. It is a fact that lithium-ion cells have a much lower self-disposal rate than other rechargeable cells, including Ni-Cad and NiMH. In the first 4 hours after being paid it normally represents approximately 5% but then amounts to about 1 or 2% a month.

Low maintenance: An significant benefit of the lithium-ion battery is its absence and maintenance in order to maintain its performance.

Ni-Cad cells had to be periodically discharged to make sure the memory effect did not appear. This process or other similar maintenance procedures are not required because it does not affect lithium-ion cells. Similarly, lead-acid cells need maintenance, some requiring daily supplementation of battery acid.

Fortunately, one of the benefits of lithium-ion batteries is that active maintenance is not mandatory.

Cell voltage: Each lithium-ion cell has a voltage of approximately 3.6 volts. This has many benefits. The voltage of each lithium-ion cell is greater and in many battery applications, it requires fewer batteries, being higher than the typical nickel-cadmium, nickel-metal hydride, and even standard alkaline cells at around 1.5 volts and lead-acid at about 2 volts per cell. A single cell is needed for smartphones, which simplifies the management of electricity.

Load characteristics: A lithium-ion cell or battery's characteristics are appropriate. Until dropping off when the last load is used, they provide a relatively steady 3.6v per cell.

No requirement for priming: When they get their first charging, some rechargeable cells need to be made. One benefit of lithium ion batteries is that they are not supplied operationally and readily available for this purpose.

Variety of types available: Multiple lithium-ion cell types are available. This benefit of the lithium-ion batteries could lead to the use of the right technology for the specific application. Certain types of lithium-ion batteries give a high current density and are suitable for mobile electronic consumer devices. Others can have substantially higher levels of current and are suitable for power tools or for electric cars.

2.Lithium-ion battery disadvantages

Like the use of any technology, the benefits have to be balanced against certain drawbacks.

Though the advantages of lithium-ion battery technology are, these cannot be overcome or, at least, the excellent performance obtained is mitigated.

The Li-ion battery disadvantages include:

Protection required: Lithium-ion cells and batteries are not as robust as some others. They need to be shielded from being charged and released too far. Furthermore, the current must be kept within safe limits. Accordingly, one drawback with the lithium-ion battery is that it needs a safety circuit to ensure its safe operating limits are maintained.

Fortunately, this can be reasonably quickly incorporated into the battery or into equipment with modern integrated circuit technology, if the battery is not interchangeable. The integration of the battery control circuit makes it possible to use li-ion batteries without any specific experience. They can be loaded and the charger will cut the battery supply after the full battery is loaded.

The lithium-ion safety circuit controls many aspects of its service. The safety circuit limits every cell's maximum voltage during charge because the cells can suffer from too much voltage. They are generally charged in series because typically there is only one connection for a battery and thus because different cells can need different load levels, one cell can have a higher voltage than needed.

The safety circuit prevents too low cell voltage on discharge. This can happen yet again if one cell can store a lower charge on the battery than others and its charges get tired of the other cell.

Aging: The fact that lithium-ion batteries are aging is one of the biggest drawbacks for consumer electronics. The amount of charge discharging cycles the battery underwent not only depends on the time or the calendar. Sometimes only 500 to 1000 charge-discharge cycles can be withstood by batteries before their power falls. This figure is growing with the advancement of li-ion technology but batteries need to be replaced after a while, and this can be a problem if embedded inside the device.

The batteries of lithium-ion even age, whether in use or not. Despite the use, a reduction in capability is often time-related. If a standard lithium cobalt oxide for the user is to be processed, the LCO battery or cell should be partially charged - around 40 to 50% and held in a cool range of storage. Stocking will help improve life in these environments.

Transportation: In recent years, this drawback with li-ion batteries has been illustrated. Many airlines restrict their number of lithium-ion batteries, meaning that they only hold ships.

Lithium-ion batteries often need carry-on baggage for air travelers, although this can differ from time to time with the safety role. But there could be a small number of batteries. Any lithium-ion batteries separately carried must be covered by protective covers, etc. against short circuits. It is especially important in large lithium-ion batteries, such as large power banks. It is important.

Before flying, it must be tested whether or not the big power bank can be transported. Unfortunately, the advice is not always very simple.

Cost: A significant drawback to the lithium-ion battery is its cost. They usually cost about 40% more than nickel cadmium cells to produce. This is an important factor in the use of mass-produced consumer goods, where additional costs are an important concern.

Developing technology: While lithium-ion batteries are available for several years, they may still be regarded by some as immature technology since they are very much a developing field. This may be an annoyance since the technology is not continuous. However, with the continuous advancement of new lithium-ion technologies, better solutions can also be given.

Ⅳ Li-ion Battery-18650 cell

The Lithium-Ion Battery 18650 is the most frequently used one, so in this article, you will talk about the same. The following picture shows a typical 18650 cell

18650 cell

The Li-ion battery has a voltage and power rating, as all batteries do. For all lithium cells, the nominal voltage level is 3.6V so that you need to combine two or more cells in series for higher voltage requirements. The default voltage is just ~3.6V for all lithium-ion cels. This stress can be down to 3.2V when fully loaded and up to 4.2V when fully loaded. Bear in mind that loading or charging the battery below 3.2V permanently kills the battery and may also become a fireworks formula. Let the vocabulary of a 18650 battery disintegrate so that we can better understand it. Note that these explanations only refer to a single 18650 cell, later we will get into Li-ion battery packs, in which more than one cell is connected to the voltage and current ratings in series or parallel.

Nominal Voltage: The nominal tension is the real 18650 cell voltage. By default, it is 3.6V and, despite its development, remains unchanged for all 18650 cells.

Full discharge voltage: No cell 18650 should ever release under 3.2V, as this would alter the battery's internal resistance, causing irreversible damage to the battery and leading to an explosion.

Full charge Voltage: Lithium-ion cell charging voltage is 4.2V. Please be careful not to raise the cell voltage by 4,2V at any particular time.

mAh Rating: A cell's capacity is typically given as a mAh (Milli Ampere Hour). This value varies according to the cell type that you buy. Let's suppose, for instance, that our cell here is 2000mAh, which is only 2Ah. This means that if the battery draws 2A for 1 hour and similarly if the battery draws 1A for 2 hours. But you need to measure it using the mAh rating if you want to know how long the battery will power your project (run time).

Run Time (in hours) = Current drawn / mAh Rating

Where current drawn should be within the C rating limit.

C Rating: You can find your response from the C rating of the battery if you've ever wondered what is the maximum volume you can draw from the battery. For each battery, we should say that the battery we have is a 2Ah battery with a 3C rating. The battery C rating changes again. The value 3C means the battery can produce 3 times the maximum current of the rated Ah rating. In this case, it can deliver a maximum current of up to 6A (3*2 = 6). 18650 cells normally only have a 1C grade.

Maximum current drawn from battery = C Rating * Ah Rating

Charging Current: The recharging current of a battery is another significant specification to consider. It does not mean that a battery will supply 6A with a maximum current. The battery data sheet includes the maximum charging current since it varies according to the battery. It is normally 0.5C, which is half the Ah rating value. The charging current is 1A (0.5*2 = 1) for a 2 Ah rating battery.

Charging time: For a single 18650 battery cell, the minimum charging time required can be determined with the charging current value and the battery Ah rating. For example, it takes around 2 hours to charge a 2 Ah battery that has 1A loading current, assuming that the charger only uses the CC method for charging the device.

Internal Resistance (IR): By calculating the internal resistance of the battery the health and power of a battery can be predicted. This is essentially the resistance value between the battery endpoints (positive) and cathode (negative). A data sheet shows the standard IR value of a cell. The less powerful is the battery, the more it drifts from the real value. The IR value of an 18650 cell is within a milli ohms range and the IR value has been calculated with dedicated instruments.

Charging methods: Many methods to load a li-ion cell are practiced. But 3 phase topology is the most widely used. CC, CV and trickle loading are three phases. The cell is charged by a steady charging current by changing the input voltage in CC (constant current). The mode is active until the battery is charged to a certain amount, and then the CV mode begins, where charge voltage is usually maintained at 4.2V. End mode is pulse charging or tricking, where the battery passes little current pulses to increase the battery life span. More complex chargers with 7-stage charging are also available.

State Of Charge (SOC) %: The charge status, similar to the ones in our cell phone, is nothing but battery power. With a voltage valve, a battery's capacity cannot be clearly measured, usually, it is calculated with a current integration to assess the battery capacity shift over time.

Depth Of Discharge (DOD) %: The DOD demonstrates the degree to which the battery can be unloaded. There will be no 100% discharges because the battery will be fried as we know. For all batteries, usually, an 80 percent discharge depth is set.

Cell dimension: The dimensions of the 18650 cell are another fascinating and special feature. It is named 18650 for each cell. Each cell has a dia of 18mm, and a height of 650mm.