Week 1 Understanding Different Battery Chemistry
1.Prepare a table which includes materials & chemical reactions occurring at the anode and cathode of LCO, LMO, NCA, NMC, LFP and LTO type of lithium ion cells.Give your detailed explanation on it
ans.
A battery is a source of electric power consisting of one or more electrochemical cells with external connections[1] for powering electrical devices such as flashlights, mobile phones, and electric cars. When a battery is supplying electric power, its positive terminal is the cathode and its negative terminal is the anode.[2] The terminal marked negative is the source of electrons that will flow through an external electric circuit to the positive terminal. When a battery is connected to an external electric load, a redox reaction converts high-energy reactants to lower-energy products, and the free-energy difference is delivered to the external circuit as electrical energy.[3] Historically the term "battery" specifically referred to a device composed of multiple cells, however the usage has evolved to include devices composed of a single cell.[4]
Primary (single-use or "disposable") batteries are used once and discarded, as the electrode materials are irreversibly changed during discharge; a common example is the alkaline battery used for flashlights and a multitude of portable electronic devices. Secondary (rechargeable) batteries can be discharged and recharged multiple times using an applied electric current; the original composition of the electrodes can be restored by reverse current. Examples include the lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics such as laptops and mobile phones.
Batteries come in many shapes and sizes, from miniature cells used to power hearing aids and wristwatches to small, thin cells used in smartphones, to large lead acid batteries or lithium-ion batteries in vehicles, and at the largest extreme, huge battery banks the size of rooms that provide standby or emergency power for telephone exchanges and computer data centers.
Batteries have much lower specific energy (energy per unit mass) than common fuels such as gasoline. In automobiles, this is somewhat offset by the higher efficiency of electric motors in converting electrical energy to mechanical work, compared to combustion engines.
Lithium ion cell
Lithium-ion cells are widely used for cellular phones and note-type personal computers (PCs) because of their high voltage and high energy density. More than 1000 million such cells were sold in the year 2007. Many of the commercial lithium-ion cells have lithium cobalt oxide (LiCoO2) positive electrodes, carbon negative electrodes, and nonaqueous electrolyte solutions. These cells should be safe because the various types of electronic protection devices such as overcharge protection circuit and fuse are installed in the commercial battery pack even if the battery pack employs only one cell. However, the safety margin of these cells is still small for practical use. Many accidents involving lithium-ion cells have been reported in newspapers and via the Internet since 1995. Whatever happens to the cells, the primary reason for these accidents is thermal runaway of lithium-ion cells. Abuse test results show that lithium-ion cells have two fundamental weaknesses, namely, they have insufficient tolerance to overcharging and poor thermal stability. When overcharging and heating occur simultaneously, cell safety is drastically reduced.
Studies on various new lithium-ion cells have been carried out for electric vehicles (EVs), uninterrupted power supplies (UPSs), backup power supplies (BPSs), and so on. Further trend of cell development is to make higher energy density cells and large-size cells. This trend makes cell safety a very important issue in the near future.
At present the best way to evaluate cell safety is to carry out abuse tests on bare cells without protection systems. This chapter describes the recent status of safety of practical lithium-ion cells, a theoretical approach to an understanding of cell safety, how to evaluate the safety of lithium-ion cells before practical use, and example results of safety tests of lithium-ion cells.
Types of lithium-ion batteries
Lithium-ion batteries come in a variety of shapes and sizes, and not all of them are made equal. Below are descriptions of six different lithium-ion battery types, as well as their compositions and common applications.
Lithium Cobalt Oxide
Lithium cobalt oxide batteries are manufactured from lithium carbonate and cobalt and are also known as lithium cobaltate or lithium-ion cobalt batteries. These batteries are used in cell phones, laptops, and electronic cameras because of their high specific energy. They have a cobalt oxide cathode and a graphite carbon anode, and lithium ions migrate from the anode to the cathode during discharge, with the flow reversing when the battery is charged.
This battery has a few disadvantages, including short battery life and low specific power. We also want to let you know that these batteries are not as safe as other varieties. Despite this, they are a popular choice for cell phones and other portable electronic devices because of their properties.
Lithium Manganese Oxide
Lithium manganese oxide batteries are sometimes known as lithium manganate or lithium-ion manganese batteries, or li-manganese or manganese spinel batteries. The technology for this sort of battery was initially discovered in the 1980s, with the first publication in the Materials Research Bulletin in 1983. Moli Energy manufactured the first commercial lithium-ion cells using lithium manganese oxide as the cathode material in 1996.
High-temperature stability distinguishes lithium manganese oxide batteries from others, which are also safer than other lithium-ion battery types. As a result, they’re frequently found in medical equipment and devices, but they can also be used in power tools, electric motorcycles, and other applications. Lithium manganese oxide batteries can also be used to power laptop computers and electric vehicles.
Lithium Iron Phosphate (LFP)
Phosphate is used as a cathode in lithium iron phosphate batteries, often known as li-phosphate batteries. They have low resistance qualities, which improve their thermal stability and safety.
Durability and a long lifecycle are other advantages – fully charged batteries can be kept with no effect on the battery’s overall charge life. When the lengthy battery life of Li-phosphate batteries is considered, they are frequently the most cost-effective option. The lower voltage of the lithium-phosphate battery, on the other hand, means that it has less energy than other lithium batteries.
As a result, these batteries are frequently used in electric bikes and other applications requiring a long lifecycle and high levels of safety. These batteries are also commonly used in electric vehicles.
Lithium Nickel Manganese Cobalt Oxide (NMC)
Lithium Nickel manganese Cobalt Oxide batteries, often known as NMC batteries, are constructed of a variety of materials that are universal in lithium-ion batteries. A cathode constructed of a mix of nickel, manganese, and cobalt is included.
NMC batteries, like other lithium-ion battery types, can have a high specific energy density or a high specific power. They can’t have both features, though. This battery is most commonly seen in power tools and automobile powertrains.
60% nickel, 20% manganese, and 20% cobalt are commonly the cathode combination ratios. This means that the cost of the raw material is lower than for other lithium-ion battery solutions, as cobalt may be fairly costly. Because some battery manufacturers plan to convert their battery chemistry to a larger percentage of nickel to utilize less cobalt, the price of these batteries may drop even more in the future. Because of its low self-heating rate, this battery type is often used in electric vehicles.
Lithium Nickel Cobalt Aluminum Oxide
NCA batteries, or lithium nickel cobalt aluminum oxide batteries, are making their way in electric vehicles and grid storage.
Although NCA batteries are not widely used in consumer electronics, they have great potential in the automobile industry. NCA batteries offer a high-energy choice with a long lifespan, but they are less safe than other lithium-ion battery types and are rather expensive. To ensure driver safety, NCA batteries must be accompanied by monitoring systems.
Given the widespread use of NCA batteries in electric vehicles, demand for these batteries may increase as the number of electric vehicles grows.
Lithium Titanate
Finally, lithium titanate, often known as li-titanate, is a type of battery that has a growing number of uses. Because of its superior nanotechnology, the lithium-titanate battery has an extremely rapid recharge time.
Li-titanate batteries are being employed by makers of electric vehicles and bicycles, and this type of battery has the potential to be used in electric buses for public transit. However, these batteries have a lower intrinsic voltage or energy density than other lithium-ion battery types, which might cause problems when it comes to efficiently power automobiles. Despite this, lithium titanate batteries have a higher density than non-lithium-ion batteries, which is a benefit.
These batteries could be used for military and aerospace applications, as well as storing wind and solar energy and constructing smart grids. Furthermore, according to Battery Space, these batteries could be employed in power system system-critical backups.
After understanding the types of lithium-ion batteries, let’s understand two of these batteries in depth. These batteries are NMC and LFP.
Lithium Nickel Manganese Cobalt Oxide (NMC)
A cathode combination of nickel, manganese, and cobalt is one of the most successful Li-ion systems. These systems, like Li-manganese, can be modified to serve as Energy Cells or Power Cells.
NMC in a 18650 cell for moderate load conditions has a capacity of about 2,800mAh and can produce 4A to 5A; NMC in the same cell can be optimized for specific power. For example, it can have a capacity of just about 2,000mAh but can deliver a continuous discharge current of 20A.
The capacity of a silicon-based anode can be increased to 4,000mAh and beyond, but at the cost of reduced loading capability and shorter cycle life.
The anode grows and shrinks with charge and discharge, making the cell mechanically unstable. Silicon added to graphite has the disadvantage of growing and shrinking with charge and discharge, making the cell mechanically unstable.
The combination of nickel and manganese is the key to NMC’s success. Table salt is an example of this; the major constituents, sodium, and chloride, are both harmful on their own, but when combined, they act as seasoning salt and a food preservative. Manganese has the advantage of developing a spinel structure to create low internal resistance but has low specific energy. Nickel has high specific energy but is unstable. When the metals are combined, their strengths are amplified.
For power tools, e-bikes, and other electric powertrains, NMC is the battery of choice. The cathode is commonly made up of one-third nickel, one-third manganese, and one-third cobalt, or 1-1-1. This creates a distinctive blend while also lowering the cost of raw materials due to the lower cobalt percentage. NCM, which consists of 5 parts nickel, 3 parts cobalt, and 2 parts manganese, is another excellent combination (5-3-2). It’s possible to make other combinations with different amounts of cathode materials.
To increase capacity, new electrolytes and additives are used that enable charging to 4.4V/cell and higher. There is a trend toward NMC-blended Li-ion since the system is cost-effective and provides good performance. Nickel, manganese, and cobalt are three active materials that may be easily combined to suit a wide range of automotive and energy storage systems (EES) applications that require frequent cycling. The NMC family is becoming more diverse.
2.Compare the differences between each type of Li+ion batteries based on their characteristics
ans.
For more details i have uploaded comparison.xls file