Lithium-ion battery : A Complete Introduction
Battery is everywhere in our life, but do you really know what battery is? Do different devices use the same battery? What’s the difference between battery and battery that used in different devices? I guess you probably can’t answer, so before reading this article about lithium-ion battery, we need to know what is battery.
Battery, refers to a part of the space of a cup, tank or other container or composite container that containing electrolyte solution and metal electrode to generate electric current, is a device that can convert chemical energy into electrical energy.
It has two electrodes. The positive terminal is the cathode and negative terminal called anode.
With the progress of science and technology, battery generally refers to the small device that can generate electric energy.
Using the battery as the energy source, we can get stable voltage, stable current, stable power supply for a long time, and little affected by the external environment. Moreover, the battery has simple structure, easy to carry and to charge/discharge operation, which plays an important role in all aspects of modern social life.
In this article, you will not only know the battery industry terms, basic composition, classification, but also the specially complete introduction about the newly developing Lithium-ion battery. Let’s go on reading!
Battery industry terms
There are some industry terms you need to know before the following contents, which will help you get a better understanding.
There are two types of battery packs, in series and in parallel. The voltage of each battery in parallel is required to be same. The parallel battery pack can provide stronger current. There is no excessive requirement for series battery pack.
(2)Beginning of life(BOL).
It refers to the energy and capacity of battery when it is just assembled or in the initial state of battery life.
(3)End of life(EOL).
When the maximum storage energy or power of the battery is reduced to a certain proportion of the initial state of life, it is called the end of life.
The battery completes a charge-discharge progress called a cycle.
It means the energy per unit mass or volume of a battery. The energy density is inversely proportional to the volume of battery, apart from other circumstances, the higher the energy density, the smaller the battery volume.
It’s an efficient battery manufacturing technology, which refers to stacking the cathode, anode and separator together and winding them up. Then putting them into a usually cylindrical container. It can maximize the surface area of a battery without increasing its overall volume.
As time goes on, the amplitude and direction of AC voltage will change periodically. The equipment with high power and requirement mostly adopts alternating current.
The amplitude and direction of DC voltage will not change with time. The equipment with low power and requirement often use direct current.
The most basic industry terms are here. If there are other terms that maybe a little difficult and need to explain, I will explain to you, so don’t worry.
Basic composition about battery
YouTube：How a car battery made? A look inside the Century Batteries factory(https://www.youtube.com/watch?v=G5McJw4KkG8)
There are five main basic compositions in a battery:
The positive terminal of battery called cathode, commonly use “+” to stand for.
The negative terminal of battery called anode, commonly use “-” to stand for.
Separator and jelly roll.
The separator located between the positive and negative electrodes. Its function is to separate the positive and negative electrodes to avoid internal short circuit, which caused by direct contact between the cathode and anode.
After the assembly, the battery cell needs to be packaged with metal shell, plastic shell or composite film.
It is a medium for ion transport, allowing ions to travel between the positive and negative electrodes. After the initial packaging of the battery, electrolyte injection is the last step.
In addition, there are many other small parts in the battery, such as current interrupt device, but not all types of batteries have.
Primary battery and secondary battery
Depending on whether it can be recharged several times, batteries are divided into primary battery and secondary battery.
Primary battery can not be recharged again. After discharging, this kind of battery must be disposed of or discarded, such as the alkaline battery commonly used in the small household electrical equipment.
Secondary battery is also called rechargeable battery, which can be charged and discharged for many times. Its application and life depend on the chemical battery system and environmental condition.
Lead Acid Battery, Nickel Cadmium, Sodium Based Battery and Lithium-ion Battery
According to the different raw materials used in the battery, they are divided into four different categories.
* Lead Acid Battery.
Lead acid battery is the oldest and most common secondary battery by far. Because of its stable, reliable and cheap energy supply system, it is widely used in the energy storage field. What’s more, it is the most frequently backup power supply in electric vehicles.
A Lead acid battery pack
The only disadvantage is its low cycle life, therefore, it is mainly applicable to the application area of high power, low cycle times, no limitation on quality and volume and low battery cost.
Due to its low material, manufacturing cost and high recovery rate, Lead acid battery still have a high market share.
* Nickel Cadmium.
Compared with Lead acid battery, Nickel cadmium has relatively higher voltage, higher capacity and longer cycle life, which is widely used in hybrid electric vehicles.
At the same time, Nickel cadmium has memory effect. Although the influence can be minimized by regular charge and discharge to some extent, it still seriously affects the available energy in the cycle process. Moreover, its high self discharge rate is one of the reasons that affects customers’ choice of Nickel cadmium.
* Sodium Based Battery.
Sodium based battery has low material cost and similar energy density with Nickel cadmium.
However, it needs to operate at high temperature environment, so it is mainly used in small and medium-sized energy storage power station.
* Lithium-ion Battery.
About this battery, I will introduce in detail in the following content.
YouTube：How It’s Made – Lithium Ion Batteries
Because of high energy density, Lithium-ion battery becomes the best choice for small electrical appliance power supply. It means in the situation that providing same amount of energy, Lithium-ion battery requires only half the volume and weight of Nickel cadmium. For example, in mobile power, like mobile phones and laptops, are all use Lithium-ion battery in order to have a longer running time.
Lithium-ion Battery has high working voltage. A high working voltage means that to achieve the same assembly voltage, Lithium-ion battery just needs fewer cells. This feature greatly reduces the cost of producing a battery.
And it has lower self discharge rate. It means that, after being stored for a period of time, the capacity loss of lithium-ion battery is much less than that of other battery.
More importantly, it has very excellent cycle life. The complete charge-discharge cycle life of Lead-acid battery is about 300-500 cycles, while that Lithium-ion battery can reach thousands of times.
Lithium-ion battery cell
According to the different appearance, there are three kinds of common cell in the market: columnar, square and soft package.
- Columnar cell.
The advantage is that the metal shell used is steel shell or nickel coated steel shell and aluminum shell. These metal shells need high energy to be destroyed, and the metal shell can provide “extrusion pressure” for the coil core in the shell to ensure structural stability. Therefore, there are many column cell suppliers and production equipment in the market at present.
However, the disadvantage of small cylindrical cell is its small size, which makes it difficult to seal the cover. Apart from laser welding technology, there are some lithium-ion battery manufacturers using crimping technology to seal the cell, which is easy to lead to safety problems.
And another disadvantage of the cylindrical battery is high initial impedance, which means that it has a higher heat production rate than the square or soft package battery.
- Square cell.
Square battery is usually packaged with stainless steel, plastic or aluminum materials, which is widely used in the electric vehicles area. The advantage of large square cell lies in less connection points and higher power. Fewer connection points also mean lower risk of battery failure.
- Soft package cell.
Soft package cell can be fabricated into various shapes, which is suitable for a variety of assembly systems. The biggest disadvantage is its poor safety.
In addition, when soft package is applied in the module, the auxiliary pressure is required to suppress the volume change to obtain better life performance, and the auxiliary pressure needs to be all the same throughout the cell. If the pressure is not consistent, the lithium ion movement in the cell will be limited, resulting in the increase of cell impedance, shortening of cell life, and even formation of lithium dendrite, which will lead to safety failure.
What’s more, soft package cell is packaged with polymer, which is relatively easy to be damaged in the process of cell assembly, so be careful during operation.
The factors that determine Lithium-ion battery price
The factors that determine Lithium-ion battery price are as followed but not limited to:
(1)Capacity and voltage.
Capacity and voltage are the most two important influence factors. If you require certain capacity and voltage, price will vary according to the condition.
(2) Shell size and battery pack weight.
In a similar manner, shell size and battery pack weight also need to be considered. Battery pack with small shell size and light weight always cheaper than bigger shell size and heavier battery pack.
(3) Cycle life.
Of course, longer cycle life Lithium-ion battery will have a higher price.
(4) Raw material.
It has a difference between Lithium-ion phosphate battery and Ternary lithium-ion battery, as the LFP raw material is rich in resources and the price is relatively low, while the ternary material is a little expensive.
Lithium-ion battery advantages
YouTube：Why Lithium-ion batteries are the future?
In the previous part about battery category, I have made some introduction of the advantages of Lithium-ion battery. In this part I will explain more details.
- Internal advantages.
*High energy density.
The energy density is closely related to battery volume. With high energy density, the volume of a battery is relatively small, which customers also tend to choose smaller battery to use.
*Excellent cycle life.
This advantage makes the Lithium-ion battery has longer time for customers to use, that let you possess a cost-effective battery product within your budget.
*Low self discharge rate.
According to different types of Lithium-ion battery, it self discharge rate is about 1%-5% per month, which makes your battery a longer life.
*Good safety performance
Lithium-ion battery has been put into many safety measures to keep good safety performance, such as installing a exhaust value on the battery. If the battery got something wrong, it will cause the gas generated inside to reach a high pressure, which is different from normal state, the valve will open to ensure safety.
As Lithium-ion battery has no memory effect, it don’t need periodic discharge, which can save the cost of maintenance.
What’s more, government policy support is another important advantage.
Because of the advantages of lithium-ion battery itself, many countries have issued relevant policies for lithium-ion battery to support its development, such as restricting fuel vehicles while encouraging the use of new energy vehicles with lithium-ion battery, and giving certain subsidies according to different standards.
Categories of Lithium-ion battery
According to the different materials used in the positive electrode, common Lithium-ion batteries are Lithium-ion Phosphate Battery and Ternary Lithium-ion Battery.
- Lithium-ion Phosphate Battery.
LFP, also called Lithium Ion Phosphate, is the most commonly used cathode raw material. This kind of material is rich in resources and its price is relatively low, so it is very suitable for large-scale application.
Another important reason is that LFP battery is considered as “safe” battery, but such a statement is not accurate. Because all Lithium-ion batteries have similar thermal runaway process, while the temperature that thermal runaway can reach is different. It’s just that we should admit among all Lithium-ion batteries, Lithium-ion phosphate battery has relatively good tolerance to some limited conditions such as overcharge and high temperature.
However, the energy density of Lithium-ion Phosphate Battery is lower than Ternary Lithium-ion battery, which cause its large volume, so it always be used in some big items or transportation like trucks and buses.
- Ternary Lithium-ion Battery.
Ternary materials refer to Nickel, Cobalt, Manganese or Nickel, Cobalt and Aluminum. Nickel can improve the energy density of a battery, the more Nickel, the higher battery energy; Cobalt can make a battery more stable; Manganese and Aluminum are used as support materials to reduce the battery cost.
Ternary Lithium-ion battery are more active, and higher energy density compared to Lithium-ion phosphate battery. With large discharge capacity and good cycle performance, Ternary Lithium-ion battery is increasingly concerned and recognized by the industry and customers, as a result of the dual advantages of comprehensive performance and cost.
Applications of Lithium-ion Battery
Lithium-ion battery has begun to be widely used in our life. It we want to trace its source, Lithium-ion battery can be traced back to the early 19th century.
In 1881, Jöns Jakob Berzelius found the Lithium in minerals and named it. But the first commercial Lithium-ion battery was born in 1991. Since then, Lithium-ion battery has been gradually used in many different areas:
- Mobile power.
Of course, first is in the mobile power, like laptops, mobile phones, game machines and so on. In these applications, only a small number of cells are needed.
Nowadays, Lithium-ion battery has a widely used in mobile power area. Here we can see how do a Lithium-ion battery work.
YouTube：How do Lithium-ion Batteries Work?
- Personal transportation.
There are mainly electric scooters and electric mopeds, as well as light electric vehicles.
Batteries for electric scooters are usually Lead acid battery, but Lithium-ion battery of nickel cadmium, nickel hydrogen or Lithium iron phosphate materials are also used.
Most electric mopeds use Lead acid battery, but now there are also NiMH battery and Lithium-ion battery, which can reduce the battery weight. The latter battery has high energy density, which means they can ride for longer distances. The use of Lithium-ion battery on motorcycles is mainly due to the demand of high energy and power, also its size that limits.
There are also light electric vehicles are now increasingly using Lithium-ion battery.
- Public transportation.
The application of Electrification Technology in public transport can effectively reduce fuel consumption, which promotes the development of Lithium-ion battery. In addition, with the increase of urban population, the number of private cars is increasing year by year, and problems of urban congestion and environmental pollution are becoming more and more serious.
Generally speaking, using which type of Lithium-ion battery depends on the bus trip and demand. If the battery can accept frequent fast charging without sacrificing service life and capacity, the volume and energy can be relatively small, so the weight and cost can be relatively low.
- Industrial applications.
Batteries and energy storage are widely used in industry. For example, forklift trucks and other transportation tools, golf carts, luggage carriers and ground handling vehicles in the airport are equipped with Lithium-ion battery.
- Power grid application.
Fixed energy storage devices and power grid systems are very large, including various applications and energy storage technologies.
In remote areas or places with unstable power supply, fixed energy system is more convenient. In these places, the generator is usually used to generate electricity. When the generator stops working, the battery is required to continue to supply power to maintain the uninterrupted power supply. Lithium-ion battery has a good application in those areas.
YouTube：The Future Of Energy Storage Beyond Lithium Ion Battery
- Space application.
In the early 20th century, battery system in satellite and space were generally based on NiMH and NiCd battery; Lithium-ion battery was introduced into the space area in the late 20th century.
In space area, the direct reason for introducing Lithium-ion battery is its high energy density. In these areas, the overall weight of the fuselage is critical. Using Lithium-ion battery, engineers can increase energy for the body and reduce the fuselage weight. In satellite applications, the weight is directly related to the cost, so lower battery weight means lower cost. At present, more than 98% government, private and commercial space use lithium-ion battery as power supply.
What’s more, Lithium-ion battery is very valuable for all flights: reduce the occupied volume, reduce the volume of power reserve cabin.
Constraints and limitation about Lithium-ion Battery
There are two main factors restricting the development of lithium-ion batteries: safety and recycling.
Battery safety has always been a hot issue. For Lithium-ion battery, potential risks are hidden in the process of manufacturing and using.
In the manufacturing process, electrode manufacturing, battery assembly and other processes will all have impacts on battery safety. For example, the quality control of positive and negative electrode mixing, coating, rolling, cutting or punching, assembling, adding electrolyte, sealing and other processes all affect the performance and safety of a battery.
In the process of use, overcharge or over discharge should be reduced as much as possible, especially for battery with high monomer capacity. A series of exothermic side effects may be caused because of thermal disturbance, which will result in safety problems.
Therefore, after the Lithium-ion battery is produced, a series of tests are needed to ensure the safety and reduce the potential risks before entering the market. It includes extrusion test, impact test, overcharge test, short circuit test and needle prick test.
What’s more, Lithium-ion battery also adopts many safety protection measures, such as setting battery safety valve, hot melt fuse, series connection of components with positive temperature coefficient, using thermal seal diaphragm, loading special protection circuit, special battery management system, etc..
Lead acid battery has been quite mature in the recycling technology and industry of waste battery, but the Lithium-ion battery regeneration is still in its primary stage. And there is no relevant recycling requirements and regulations for Lithium-ion battery. Because different Lithium-ion batteries have different characteristics and module structures, it is very difficult to match different modules or cells for secondary utilization. In addition, with the decrease of Lithium-ion battery price, Lithium-ion battery recycling does not have enough economic value.
However, from the perspective of resource utilization, the echelon utilization and resource recovery of Lithium-ion battery is the only way for sustainable development of the Lithium-ion battery industry and electric vehicles / energy storage industry.
Lithium-ion battery has just begun to be used in large quantities and is still in the early stage of life, which means it will take at least five years or more for battery to be recycled or remanufactured for reuse. But a large number of NiMH batteries are about to be recycled, which drives some manufacturers to build infrastructure for battery recycling, which can provide recycling experience for Lithium-ion battery in the future.
Attention should be paid when using Lithium-ion battery
In the appropriate temperature range, battery can deliver more power. When in a low temperature condition, the chemical reaction speed inside a battery becomes low, so the energy stored in the battery is greatly reduced.
Don’t store battery in garages, warehouses or sheds. Not only will the available power be reduced, but also the battery life will be shortened. In some cases, the battery may even be frozen, causing the box to break or leading to more other dangerous conditions.
Do not place a battery directly on the concrete floor. If the floor is too cold, both the battery temperature and the capacity will be reduced. Therefore, the battery should be supported away from the ground to keep it a good state.
Ideally, the battery should be placed in an isolated and temperature adjustable room, or in a temperature adjustable battery box to get the best temperature.
In the long run, battery maintenance is very important for renewable energy system. Proper maintenance can increase battery life. Increasing battery life means reducing the long terms operating cost of the system and your electricity price.
When charging, the battery may release hydrogen, so the battery box and storage place should have good ventilation system to release the hydrogen. At the same time, be careful not to put the battery in the place with gas or electrical equipment.
(4) Away from children.
Keep the battery out of the child to prevent the child from touching the battery, causing electric shock or acid burn.
(5) Avoid deep discharge.
The less the number of deep discharges, the longer the battery can be used. Deep discharge will reduce battery life expectancy.
After deep discharge, the battery should be charged as soon as possible. In order to prolong the battery life, it should not be placed in low power state for too long. One way to reduce deep discharge is to save energy and improve power efficiency. For example, turning off lights or electrical equipment to save energy when not in use.
Of course, if you have special demands, you can ask for a customization.
At the beginning of customization, the most important thing for designer is to discuss with you about the detailed requirements.
When you want a customization, you need to think about the shell size, battery capacity, voltage, special charge-discharge rate and so on in advance.
For designers, the purpose of communication with customers is to better understand the information required for battery design. After communication, it may be found that the voltage range required is wider than originally proposed, or the system can be further optimized to meet customers’ special needs.
Battery designers need to know the requirements about charge-discharge cycles and the frequency of charge-discharge that you want to achieve. Maybe it’s used a few times a year or every day. Base on these cases, the energy storage system meeting the requirements of cycles is completely different.
The most important thing for a designer to design a battery is to ensure that they have a complete understanding of the actual needs of customers. However, some customers will not list their demands in detail. At this situation, designers will keep in close contact with you, ask as many questions and negotiate as possible to help you clarify their complete requirements, such as how much power is required for electric vehicles, how long the designed driving range is, and how long the cycle life is. Once this information is clear, it will be much easier for battery system engineers to design.
What’s more, there is also an indispensable point that you need to tell your seller what country do you live in, as seller need to prepare the required certificate in advance.
At the end of this article, if you still have some questions, just feel free to contact us to ask.