Lithium batteries have been the ones that have been imposed in new mobile devices , laptops, and even in other devices such as robots, vacuum cleaners, cordless tools, etc. However, they are not the only batteries that exist, nickel ones are also quite popular, although they are relegated to other types of devices.
For this reason, in this article I will show you everything you need to know about these batteries or rechargeable batteries, the differences, and their most notable advantages and disadvantages…
Index of contents
- History of rechargeable batteries
- Rechargeable Battery Features
- Nickel Metal Hydride (NiMH) Rechargeable Batteries
- Advantages
- Disadvantages
- Lithium Ion (Li-Ion) rechargeable batteries
- Advantages of lithium batteries (Li-Ion)
- Disadvantages of a lithium (Li-ion) battery
- Lithium Polymer (Li-Po) Battery
History of rechargeable batteries
The first rechargeable battery in history was one based on lead acid, that is, a secondary battery or accumulator, as it is usually called. These types of batteries are still present in many current vehicles. It was developed in France in the mid-19th century. Before that, all batteries were primary cells, which meant they couldn’t be recharged.
In 1899, Waldemar Jungner, in Sweden, invented the nickel-cadmium (NiCd) battery , which used cadmium as the positive electrode (cathode) and nickel as the negative electrode (anode). These types of batteries or cells also became popular, although their high price compared to lead limited their expansion to certain areas.
Later, in 1990, European environmentalists began to worry about the damage caused to the environment by NiCd batteries, so they would end up being restricted in the European Union under the Battery Directive 2006/66/EC . Currently they can only be found for industrial use, but they do not have a good enough alternative.
An alternative for this type of rechargeable batteries also arose from the hand of nickel, but this time in the form of NiMH (nickel-metal hydride) . This type of battery is more respectful with the environment but with characteristics similar to NiCd. For this reason, they have spread as one of the most used batteries in all kinds of everyday devices: watches, flashlights, remote controls, scales, some wireless peripherals, etc.
Currently, since lithium batteries were first introduced in 1991 by Sony, most efforts are focused on improving the capacity and energy density that can be stored in this type of battery, as well as optimizing other features such as extending the useful life, make it more respectful with the environment, get faster charges, etc. And it is that lithium has great advantages, which is why it is the current king of mobile devices, robots, laptops, electric vehicles, digital cameras, wireless tools, etc.
The market for devices that use batteries is huge and growing. For this reason, the battery business has become one of the most fruitful today. In addition, the marketing departments of companies are selling it as something ECO or respectful, despite the fact that the production and recycling of batteries is a challenge.
Rechargeable Battery Features
When you are going to choose a new battery for a device, you should know some of the most important features to look for:
- Battery type:There are many types and formats of batteries that you should be aware of, as otherwise they may not be compatible with the device. For example, we have flask batteries, button batteries, etc.
- Voltage:it is the voltage that the battery is capable of supplying. Although it can later be rectified by other additional circuits, it is also important depending on what you are going to use it for.
- Discharge Rate Curve: Thisis a graph of voltage as a function of percentage of capacity discharged. A flat discharge rate curve would be optimal because it means that the voltage remains constant as the battery wears down. That is, from when it is at 100% until it is exhausted at 0%, it would give a stable voltage.
- Capacity:is the amount of electrical energy involved in an electrochemical reaction. It can be measured with different units, such as Whr or watts per hour that it is capable of giving, or also in mAh or milliamps per hour. For example, a 3000 mAh battery is capable of delivering 3 A for one hour or 1.5 A for two hours, and so on…
- Energy Density:Specific is the energy that can be obtained per unit mass of the cell (or sometimes per unit mass of active electrode material). It is the product of the specific capacity and the operating voltage during a complete discharge cycle. The higher it is, the better, since the more energy you will have with the same weight.
- Power density:it is the power that can be obtained per unit mass of the cell and is measured in W/kg or watts per kilogram. That is, for each kilogram of battery, how many watts of power can it provide.
- Temperature dependence:the speed of the reaction in the cell will depend on the temperature according to the kinetic theories. Internal resistance also varies with temperature; low temperatures produce higher internal resistance. At very low temperatures, the electrolyte can freeze and provide a lower voltage, because the movement of ions is impeded. At very high temperatures, the chemicals may break down or there may be enough energy available to trigger unwanted reversible reactions, reducing efficiency.
- Useful life:another very important factor, since it will determine how long the battery will last. Rechargeable battery life cycle is defined as the number of charge/discharge cycles a secondary cell can complete before its capacity drops to 80% of its original value. This varies greatly depending on the type of battery (lithium, Nickel…). Some can last thousands of cycles before showing less and less capacity.
- Deep discharge capacity:there is a logarithmic dependence between the depth of discharge and the battery life, so the battery life can be significantly increased if the battery is not fully discharged; for example, if you keep the battery between 40 and 80% charge, it will last longer than if it is completely discharged or with higher values.
You may also be interested in knowing:
- mAh: what is it
- whhr: what is it
Nickel Metal Hydride (NiMH) Rechargeable Batteries
For nearly half a century, battery-powered devices have used almost exclusively nickel-cadmium (NiCd) rechargeable batteries. But after its restriction in the 90s for environmental reasons, those of nickel-metal hydride or NiMH that we all know today began to become popular.
This type of battery differs from lithium in that the cells have a nickel structure similar to NiCd, and usually come in button, cylindrical, prismatic, or rectangular housings. They are the most common batteries in all kinds of everyday objects that work with them, from a flashlight, through a watch, to a radio control toy.
Advantages
The advantages of NiMH batteries are:
- They can have a higher density than NiCd, which means charges up to 30-40% higher.
- They are not as prone to memory effect as NiCd ones.
- Easy to store and transport. They are not subject to any control.
- Respectful with the environment, it contains only toxins that are not too worrying, such as cadmium (a heavy metal).
- The nickel content makes recycling viable.
Disadvantages
As for the most notable disadvantages are:
- Limited shelf life. After a deep discharge, its capacity will be limited.
- It requires a complex upload algorithm.
- It tolerates overload poorly. Therefore, it is not good to leave them charging beyond the estimated time.
- Generates heat during charging.
- High self-discharge when not in use.
- Efficiency decreases if the battery is stored at higher temperatures. It should be charged to 40% stored in a cool place to.
Lithium Ion (Li-Ion) rechargeable batteries
John B. Goodenough invented lithium-cobalt oxide cells in 1922. However, a few years before that, Sony had already announced that it had an international patent on the lithium-cobalt oxide cathode. After years of litigation to obtain the patent, Sony managed to win the legal battle of what has become the most important battery today.
These lithium batteries have a higher energy density , so they can store more charge in the same space, which is a huge advantage. The cells can have a voltage of up to 3.6V and improved active materials and electrolytes can further increase the density of these batteries.
Not only that, the charging characteristics are also very good, the discharge rate curve is quite flat at 3.7-2.8V/cell and they hardly suffer from memory effect. As for their production price, they have been dropping exponentially as technology has improved. For example, in 1994 18650 batteries could cost up to $10 per unit for 1100 mAh capacities. In 2001, capacities of 1900 mAh had already been achieved with production costs below $3 and this has continued to this day.
It should also be noted that lithium batteries hardly need maintenance , which is a great advantage over others such as lead batteries. You also don’t have to worry about the deliberate full download, since it’s not necessary. And the self-discharge rate is even less than half that of nickel-based batteries, which is a good thing.
3.60V nominal cell voltage can directly power digital devices such as laptops, mobile devices, etc. Disadvantages include the need for protection circuitry to prevent possible spontaneous ignition or explosion. An additional disadvantage is the high price.
The types of lithium-ion batteries are classified according to the electrochemical systems used in them:
- (+) MLi / organic electrolyte / C (–), where the letter M indicates the base metal of the electrode
- C – cobalt
- N – nickel
- M – manganeso
- V – vanadium
- T-titanium
Lithium ion batteries have sealed casings that contain protective control circuitry. The electrode materials are applied on very thin films (copper and aluminum), divided by a separator.
Advantages of lithium batteries (Li-Ion)
Among the main advantages of lithium batteries are:
- High density.
- Low self-discharge rate, being less than half that of NiCd and NiMH
- They are not affected by the memory effect.
- low maintenance
- They do not need periodic decara.
Disadvantages of a lithium (Li-ion) battery
On the other hand, the disadvantages of lithium-ion batteries are:
- You need a protection circuit to limit the voltage and current.
- It ages and has a limited shelf life, similar to other chemicals.
- Strict transportation regulations apply to this type of battery due to the risk of ignition or explosion when reacting on contact with oxygen in the air.
Lithium Polymer (Li-Po) Battery
At the beginning of the 21st century, the first lithium polymer batteries were developed . They became very famous as an alternative to Li-Ion, although the truth is that there are more Li-Ion batteries on the market than Li-Po. However, it must be recognized that they have their advantages over Li-ion batteries, but they also have some limitations.
In this case, the batteries are differentiated by the type of electrolyte used , which is a lithium polymer. It was first developed in the 1970s, resulting in a polymer to create a solid, dry, plastic-like electrolyte. In this way, ionic exchange is possible and the electrolyte-saturated porous separator of Li-Ion batteries is replaced. What is achieved is that they do not have as much danger of spillage.
Solid polymer has poor conductivity at room temperature and the battery must be heated to 50-60°C (122-140°F) to allow current to flow, something that was not the case with Li-Ion batteries. For a modern lithium polymer cell to conduct electricity at room temperature, the electrolyte gels . That is, the current Li-Po batteries do not really have a polymer, but a gel.
Lithium polymer can be built in a number of ways, such as:
- Li-cobalt
- NMC
- Li-phosphate
- Rebuild it
For this reason, the lithium polymer battery is not considered special compared to the lithium ion battery. Most lithium-polymer secondary cells intended for the consumer market are based on lithium-cobalt circuitry . As far as the user is concerned, a lithium polymer is essentially the same as a lithium ion battery. Both systems use identical anode and cathode material and contain a similar amount of electrolyte.
Although the characteristics and efficiency of both systems are similar , the lithium polymer is special because it is a microporous electrolyte and replaces the traditional porous separator. The gelled electrolyte becomes a catalyst that improves electrical conductivity. Lithium polymer offers a slightly higher specific energy and batteries using it can be thinner than conventional lithium ion cells.
But in exchange for these advantages we have a production cost that can be between 10% and 30% higher compared to Li-Ion batteries . For this reason, they are not usually seen in most devices, which prefer to continue using Li-Ion. They are only common on some premium models where price is not an issue.
While a standard lithium-ion battery requires a rigid case to compress the electrodes, lithium-polymer uses laminated sheets that do not require compression . Such an aluminum case reduces weight by more than 20%, in addition, thin-film technology makes format design free, and the battery can be made in any shape.
We recommend the article on how to take care of the laptop battery .
Lastly, the charge and discharge characteristics of lithium polymer are identical to other lithium ion systems and do not require a special charger. The security aspects are also similar.