The growing consumer interest in mobile gadgets and high-tech portable technology in general is forcing manufacturers to improve their products in a variety of ways. At the same time, there are a number of common parameters that are being worked on in the same way. These include the energy supply method. Only a few years ago, active market participants could observe the process of crowding out NiCd nickel-cadmium batteries with more advanced elements of nickel-metal hydride origin NiMH. Today, new battery generations are competing with each other. Widespread lithium-ion technology in some segments is successfully replacing lithium-polymer battery. The difference from the ion in the new unit is not so noticeable for the average user, but in some aspects it is significant. At the same time, as in the case of competition between the NiCd and NiMH elements, the replacement technology is far from perfect and is inferior in some respects to its analogue.
Li-ion Battery Device
The first models of commercial lithium-based batteries began to appear in the early 1990s. However, cobalt and manganese were then used as the active electrolyte. In modern lithium-ion batteries, it is important not so much the substance as the configuration of its placement in the unit. Such batteries consist of electrodes that are separated by a separator with pores. The mass of the separator, in turn, is just soaked with electrolyte. As for the electrodes, they are represented by a cathode base on aluminum foil and a copper anode. Inside the block, the cathode and anode are interconnected by current collector terminals. Charge maintenance performs a positive charge of lithium ion. This material is advantageous in that it has the ability to easily penetrate into the crystal lattices of other substances, forming chemical bonds. However, the positive qualities of such batteries are increasingly not enough for modern tasks, which led to the emergence of Li-pol elements, which have many features. In general, it is worth noting the similarity of lithium-ion power sources with helium full-size batteries for cars. In both cases, the batteries are designed with physical practicality in mind. In part, this direction of development was continued by polymer elements.
Lithium polymer battery device
The impetus for improving lithium batteries was the need to combat the two shortcomings of existing Li-ion batteries. Firstly, they are unsafe to operate, and secondly, they are quite expensive at a price. Technologists decided to get rid of these disadvantages by changing the electrolyte. As a result, a polymer electrolyte replaced the impregnated porous separator. It should be noted that the polymer was previously used in electrical needs as a plastic film that conducts current. In a modern battery, the thickness of the Li-pol cell reaches 1 mm, which also removes the restrictions on the use of various shapes and sizes from developers. But the main thing is the lack of liquid electrolyte, which eliminates the risk of ignition. Now it’s worth to take a closer look at the differences from lithium-ion cells.
What is the main difference from an ion battery?
The fundamental difference is the rejection of helium and liquid electrolytes. For a more complete understanding of this difference, you should turn to modern models of car batteries. The need to replace liquid electrolyte was, again, due to safety concerns. But if in the case of automobile batteries, progress has stopped on the same porous impregnated porous electrolytes, then lithium models have received a full-fledged solid foundation. Why is a solid-state lithium polymer battery so good? The difference from the ionic one is that the active substance in the form of a plate in the zone of contact with lithium prevents the formation of dendrites during cycling. Just this factor excludes the possibility of explosions and fires of such batteries. This is just about the merits, but there are also weaknesses in the new batteries.
Lithium Polymer Battery Life
On average, such batteries can withstand about 800-900 charge cycles. This indicator is modest against the background of modern analogues, but not even this factor can be considered as determining the resource of an element. The fact is that such batteries are subject to intense aging, regardless of the nature of operation. That is, even if the battery is not used at all, its life will be reduced. And it doesn’t matter if it’s a lithium-ion battery or a lithium-polymer cell. All lithium-based power supplies are characterized by this process. A significant loss in volume can be seen already a year after the acquisition. After 2-3 years, some batteries fail at all. But a lot depends on the manufacturer, since within the segment there are also differences in the quality of battery performance. Similar problems are also characteristic of NiMH elements, which undergo aging under sharp temperature fluctuations.
disadvantages
In addition to problems with fast aging, such batteries need an additional protection system. This is due to the fact that internal stress in different areas can lead to burnout. Therefore, a special stabilization scheme is used to prevent overheating and overcharging. The same system entails other disadvantages. The main one is current limitation. But, on the other hand, additional protective circuits make the lithium-polymer battery safer. Difference from ionic in terms of cost also takes place. Polymer batteries are cheaper, but not by much. Their price tag is also rising due to the introduction of electronic protective circuits.
Operational features of gel-like modifications
In order to increase the electrical conductivity, technologists still add a gel-like electrolyte to the polymer elements. There is no talk of a complete transition to such substances, since this contradicts the concept of this technology. But in portable technology, it is often hybrid batteries that are used. Their feature is their sensitivity to temperature. Manufacturers recommend the use of such battery models in conditions of 60 ° C to 100 ° C. This requirement has determined a special niche of application. You can use gel-like models only in places with a hot climate, not to mention the need for immersion in a thermally insulated body. Nevertheless, the question of which battery to choose - Li-pol or Li-ion - is not so acute in enterprises. Where temperature has a special effect, combined solutions are often used. Polymer elements in such cases are usually used as backup.
Optimal charging method
The usual recharge time for lithium batteries is on average 3 hours. Moreover, the unit remains cold during charging. Filling takes place in two stages. At the first, the voltage reaches peak values, and this mode is maintained up to a set of 70%. The remaining 30% is gained under normal voltage conditions. Another question is also interesting - how to charge a lithium-polymer battery if it is necessary to maintain its full volume in constant mode? In this case, follow the recharge schedule. This procedure is recommended to be performed approximately every 500 hours of operation with full discharge.
Precautionary measures
During operation, only a charger that is suitable for its characteristics should be used, connecting it to a network with a stable voltage. It is also necessary to check the condition of the connectors so that the battery does not open. It is important to consider that, despite a high degree of safety, it is still a type of battery sensitive to overloads. The lithium-polymer cell does not tolerate excess current, excessive cooling of the external environment and mechanical shock. However, for all this indicator polymer blocks are still more reliable than lithium-ion ones. Nevertheless, the main aspect of safety is the harmlessness of solid-state power supplies - of course, provided that their tightness is maintained.
Which battery is better - Li-pol or Li-ion?
This issue is largely determined by operating conditions and the target of energy supply. The main advantages of polymer devices are rather tangible for the manufacturers themselves, who can freely use new technologies. For the user, the difference will be subtle. For example, in the matter of how to charge a lithium-polymer battery, the owner will have to pay more attention to the quality of the power source. In terms of charge time, these are identical elements. As for durability, the situation in this parameter is also ambiguous. The aging effect is more characteristic of polymer elements, but practice shows different examples. For example, there are reviews of lithium-ion cells that become unusable after a year of use. A polymer in some devices are operated for 6-7 years.
Conclusion
Around the batteries, there are still many myths and false judgments that relate to the different nuances of operation. Conversely, some battery features are hushed up by manufacturers. As for myths, one of them refutes the lithium-polymer battery. The difference from the ionic counterpart is that polymer models experience less internal stress. For this reason, recharging sessions of batteries that have not yet run out do not adversely affect the characteristics of the electrodes. If we talk about the facts hidden by manufacturers, then one of them concerns longevity. As already mentioned, the battery life is characterized not only by a modest indicator of charging cycles, but also by the inevitable loss of the useful volume of the battery.