What Is Rechargeable Battery

1.The Description of Rechargeable Battery

A storage battery, or called rechargeable battery, It refers to the general term of all the chemical energy batteries that can be recharged and reused after a certain amount of electricity is used. The reason why it can be charged is that the chemical reaction can be reversed after the external power supply is connected. To be exact, some diverse electrode materials and electrolytes are combined, containing lead–acid, zinc-air, nickel–cadmium (NiCd), nickel–metal hydride (NiMH), lithium-ion (Li-ion), Lithium Iron Phosphate (LiFePO4), and lithium-ion polymer (Li-ion polymer). At this point, there are many kinds of chemicals used to make batteries, and their designs are also different. Therefore, their voltage, capacity, appearance size and weight are also different.

Nowadays, the rechargeable battery is widely used in various equipment, including automobile starter, different portable devices and tools, uninterruptible power system, etc. The requirements of hybrid electric vehicles and pure electric vehicles for storage batteries make the their technology continuously innovated in order to reduce the cost and improve the performance, such as reducing its weight and increasing its lifetime. Compared with the primary battery, the rechargeable battery has a lower impact on the environment and less carbon emission in the whole life cycle, and most of them can be recycled. In spite of the initial cost of the storage battery is high, the average cost of it is cheaper than that of the primary battery, because it can be reused for many times.

2.The Applications of Rechargeable Battery

The equipment applied for storage batteries contain car starters, light vehicles, (such as electric wheelchairs, golf trucks, electric bikes, and electric forklifts), devices, uninterruptible power supply, and battery stockpiling power stations. Arising applications in half and half interior ignition battery and electric vehicles drive the innovation to lessen cost, weight, and size, and increment lifetime.

Earlier battery-powered batteries self-charge moderately quickly, and require charging before first use. Those more up to date low self-charge NiMH batteries are able to hold their charge for a long time, and are normally sold plant charged to about 70% of their appraised limit.

Battery stockpiling power stations utilize battery-powered batteries for load-leveling (putting away electric energy on occasion of low interest for use during top periods) and for environmentally friendly power utilizes, (for example, putting away force created from photovoltaic exhibits during the day to be utilized around evening time). Burden leveling decreases the most extreme force which a plant must have the option to produce, lessening capital expense and the requirement for cresting power plants.

As indicated by a report from Research and Markets, the investigators conjecture the worldwide battery-powered battery market to develop at a CAGR of 8.32% during the period 2018–2022.[4]

Little battery-powered batteries can control convenient electronic gadgets, power apparatuses, machines, etc. Substantial batteries power electric vehicles, going from bikes to trains and ships. They are utilized in appropriated power age and in independent force frameworks.

3.Common Types of Rechargeable Battery

Lead Acid Battery

It is a kind of storage battery which electrodes are mainly made of lead, and the electrolyte is sulfuric acid solution. Generally, there are two types of lead acid batteries:open-type batteries and valve-regulated batteries. The former requires regular acid injection for maintenance, but the latter is a maintenance-free battery. According to the battery model, the lead acid battery can be divided into small density, medium density and large density.

In 1859, French physicist Gaston Planté invented the lead acid battery. It has low capacity and heavy weight, but it can provide a very stable current. It is widely used in automobile electricity to provide starting current for the engine. However, because lead is harmful to the environment, it needs to be recycled carefully when it is disposed of, and please be careful when using it.

Nickel-cadmium battery（Ni-Cd）

The voltage of Nickel-cadmium battery is 1.2V, and the voltage is quite stable during the discharge process, which is similar to the 1.5V of the widely used carbon-zinc battery and alkaline battery, so it is mostly made with the same appearance size as carbon battery and alkaline battery. To replace these disposable batteries, nickel-cadmium batteries have been widely used in handheld devices. The capacity of Nickel-cadmium battery is higher than that of lead acid batteries, but the cost is higher, and the self-discharge is larger and it possesses a memory effect. However, cadmium is a hazardous substance and is not environmentally friendly.

Ni-MH Battery

The voltage of Ni-MH battery is 1.2V like Nickel-cadmium battery. Its early capacity is only slightly larger than that of Nickel-cadmium battery, but its output current is lower and its self-discharge is larger. However, as the technology matures, the capacity of Ni-MH battery increases greatly, and the output current is larger than Nickel-cadmium battery. Some specific products of Ni-MH batteries can output more than 10C current, and unlike nickel-cadmium batteries that contain toxic substances, they are environmentally friendly batteries and have no memory effect. In 2005 A new low self-discharge Ni-MH battery was introduced, which greatly improved the self-discharge problem, even lower than that of lithium ion batteries. As a matter of fact, Ni-MH batteries can be said to have completely replaced Ni-Cd batteries and have a wider range of applications.

In addition to handheld electronic products, high-power versions of Ni-MH batteries are also used in hybrid vehicles. The representative is Toyota Prius. The longest operating case is that its Ni-MH batteries have been used for more than 10 years. In Japan, the market share of Ni-MH batteries is 22%, and in Switzerland it is as high as 60%. However, it has started to decline in recent years, mostly due to partial replacement of lithium ion batteries.

Lithium Ion Battery（Li-ion）

The voltage of lithium ion battery is about 3.6-3.7V (4.2V when fully charged), which is the highest energy density among the widely used batteries, that is, the lightest, and has no memory effect and low self-discharge, but it still has shortcomings. The manufacturing cost is higher than other widely used batteries, and the safety is poor. There have also been cases of smoke, fire, and explosion from lithium batteries in mobile phones and laptops (most of which are caused by improper use or poor quality batteries). When the self-discharge of lithium ion battery is in its worst condition, it loses about 20% of its total capacity every three months in a room temperature environment of 25°C under full power. However, advanced lithium ion battery process technology can overcome this shortcoming and improve safety, but its cost is relatively high.

Lithium ion batteries used in most electronic products are often LiCoO2, with higher energy density (larger capacity), other types such as LiFeP, LiMnO, LiNiMnCoO… which are lower capacity and more expensive. Due to the high cost and the need to add a protection circuit to avoid over-discharge, which further increases the cost, so the early lithium ion batteries were mostly used in higher-priced products, such as notebook computers and mobile phones, and they are now more popular. Since lithium ion batteries have no memory effect, even new batteries do not need to be depleted and recharged. lithium ion batteries are developing rapidly, and their safety continues to increase. Pure electric vehicles are also being used. What’s more, applications of lithium ion batteries are gradually being found in avionics and military equipment.

Lithium Ion Polymer Battery (Li poly)

The basic structure of lithium ion polymer battery is the same as lithium ion batteries. The difference is that lithium ion polymer battery replace the organic solution in lithium ion battery with solid polymers. Compared with lithium ion battery, it has the advantages of low cost, easy to produce a variety of different shapes, and more reliable. But its disadvantage is that the capacity is slightly lower. The carefully designed lithium polymer battery has high discharge capacity, and its continuous discharge coefficient is even as high as 90C or higher.

4.What is Charging and Discharging

In charging process, the positive dynamic material is oxidized, creating electrons, and the negative material is decreased, burning-through electrons. These electrons comprise the current stream in the outer circuit. The electrolyte may fill in as a straightforward cushion for inward particle stream between the anodes, as in lithium-particle and nickel-cadmium cells, or it very well might be a functioning member in the electrochemical response, as in lead–corrosive cells.

The energy used to charge battery-powered batteries generally comes from a battery charger utilizing AC mains power, albeit some are prepared to utilize a vehicle’s 12-volt DC electrical plug. The voltage of the source must be higher than that of the battery to constrain current to stream into it, however not all that a lot higher or the battery might be harmed.

Chargers take from a couple of moments to a few hours to charge a battery. Slow “imbecilic” chargers without voltage or temperature-detecting abilities will charge at a low rate, regularly taking 14 hours or more to arrive at a full charge. Quick chargers can normally charge cells in two to five hours, contingent upon the model, with the quickest taking as meager as fifteen minutes. Quick chargers must have various methods of distinguishing when a cell arrives at full charge (change in terminal voltage, temperature, and so on) to quit charging before unsafe cheating or overheating happens. The quickest chargers regularly join cooling fans to shield the cells from overheating. Battery packs planned for quick charging may incorporate a temperature sensor that the charger uses to ensure the pack; the sensor will have at least one extra electrical contacts.

Diverse battery sciences require distinctive charging plans. For instance, some battery types can be securely revived from a steady voltage source. Different sorts should be accused of a directed current source that tightens as the battery arrives at completely energized voltage. Charging a battery mistakenly can harm a battery; in outrageous cases, batteries can overheat, burst into flames, or dangerously vent their substance.