Lithium polymer battery: unlike ion battery, service life, device. Li-pol or Li-ion: which is better

The growth of consumer interest in mobile gadgets and technological portable technology generally forces manufacturers to improve their products in a variety of ways. At the same time, there are a number of common parameters, the work on which is carried out in the same vein. These include the energy supply method. Only a few years ago, active market participants could observe the process of displacement of nickel-cadmium NiCd batteries with more advanced elements of nickel-metal hydride NiMH. Today, rivalry is led by a new generation of batteries. The widespread lithium-ion technology in some segments successfully replaces the lithium-polymer battery. The difference from ionic in the new block 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 NiCd and NiMH cells, the replacement technology is far from flawless and inferior to the analogue in some respects.

Battery charger Li-ion

The first models of lithium-based serial batteries began to appear in the early 1990s. However, cobalt and manganese were used as the active electrolyte. In modern lithium-ion batteries, it is not so much the substance that matters, but the configuration of its placement in the unit. Such batteries consist of electrodes, which are separated by a separator with pores. The weight of the separator, in turn, is just impregnated with the electrolyte. As for the electrodes, they are represented by a cathode base on an aluminum foil and a copper anode. Inside the block, the cathode and anode are connected to each other 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 appearance of Li-pol elements, which have many features. In general, it is worth mentioning the similarity of lithium-ion power sources with helium full-length batteries for cars. In both cases, the batteries are designed with the expectation of physical practicality in use. In part, this direction of development has continued and the polymer elements.

Device of lithium polymer battery

The impetus for improving lithium batteries was the need to combat the two drawbacks of existing Li-ion batteries. First, they are not safe to operate, and secondly, they are quite expensive at the price. To get rid of these minuses, technologists decided by changing the electrolyte. As a result, the polymer electrolyte came to replace the impregnated porous separator. It should be noted that the polymer was previously used in electrical needs as a plastic film that conducts a current. In the modern battery, the thickness of the Li-pol element reaches 1 mm, which also removes restrictions on the use of different shapes and sizes. But the main thing is that there is no liquid electrolyte, which eliminates the risk of ignition. Now it is worthwhile to consider in more detail the differences from lithium-ion elements.

What is the main difference from an ion battery?

The principal difference is the rejection of helium and liquid electrolytes. For a more complete understanding of this difference, one should turn to modern models of car batteries. The need to replace the liquid electrolyte was due, again, to security interests. But if in the case of car batteries progress has stopped on the same porous electrolytes with impregnation, then the lithium models have received a solid solid foundation. What is so good about a solid-state lithium-polymer battery? The difference from the ionic one lies in the fact that the active substance in the form of a plate in the contact zone with lithium interferes with the formation of dendrites during cycling. This factor excludes the possibility of explosions and fires of such batteries. This is only about virtues, but there are also weaknesses in new batteries.

Lifetime of lithium polymer battery

On average, such batteries can withstand about 800-900 charge cycles. This indicator is modest against the background of modern analogs, but not even this factor can be considered as determining the resource of the element. The fact is that such batteries are subject to intense aging, regardless of the nature of the operation. That is, even if the battery is not used at all, its resource will be reduced. And it does not matter, it's a lithium-ion battery or a lithium polymer element. All lithium based power supplies are characterized by this process. A significant loss in volume can be noticed already a year after the acquisition. After 2-3 years some batteries are completely out of order. But much depends on the manufacturer, because within the segment there are also differences in the quality of the battery. Similar problems are also present in NiMH cells, which are subject to 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 drawbacks. The most important of these is current limitation. But, on the other hand, additional protective circuits make a lithium polymer battery safer. The difference from ionic in terms of cost also takes place. Polymer batteries are cheaper, but not much. Their price tag also increases due to the introduction of electronic protective circuits.

Operational features of gel-like modifications

In order to increase the electrical conductivity, a gel electrolyte is added to the polymer elements of the technology. There is no question of a full transition to such substances, since this contradicts the concept of this technology. But in portable technology, hybrid cells are often used. Their feature is the sensitivity to temperature. Manufacturers recommend using such models of batteries in conditions from 60 ° C to 100 ° C. This requirement has determined a special niche of application. Use gel-like models only in places with a hot climate, not to mention the need to immerse in a heat-insulated housing. Nevertheless, the question of which battery to choose - Li-pol or Li-ion, - is not so acute in enterprises. Wherever temperature has a special effect, combined solutions are often used. In such cases, the polymer elements are used as reserve elements.

Optimum charging method

The normal charging time for lithium batteries is on the average 3 hours. Moreover, during the charging process the unit remains cold. The 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% are already collected under normal stress conditions. Another interesting question is how to charge a lithium-polymer battery, if it is necessary to maintain its full volume in a constant mode? In this case, you should follow the schedule for recharging. This procedure is recommended to be performed approximately every 500 hours of operation with full discharge.

Precautionary measures

In the process of operation, only a suitable charger 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 take into account that, despite the high degree of safety, it is still a battery-sensitive type of overload. The lithium polymer element does not tolerate exceeding the current indicators, excessive cooling of the external environment and mechanical shocks. However, for all these indicators, polymer blocks are still more reliable than lithium-ion ones. Still, the main safety aspect is the harmlessness of solid-state power supplies - of course, provided they are kept tight.

Which battery is better - Li-pol or Li-ion?

This issue is largely determined by the operating conditions and the target of the power supply. The main advantages of polymer devices are rather tangible for 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 supply source. By the time of the same charge, these are identical elements. As for durability, in this parameter, too, the situation is ambiguous. The effect of aging is more characteristic of polymer elements, but practice shows different examples. For example, there are reviews about lithium-ion cells, which become unusable after a year of use. And polymeric in some devices are operated for 6-7 years.

Conclusion

Around batteries there are still many myths and false judgments, which relate to different nuances of exploitation. And on the contrary, some features of batteries are hushed up by manufacturers. As for the myths, one of them disproves the lithium-polymer battery. The difference from the ionic analogue is that the polymer models experience fewer internal loads. For this reason, charging sessions of still unoccupied batteries do not adversely affect the characteristics of the electrodes. If we talk about the facts hidden by the producers, then one of them concerns durability. As already mentioned, the battery life is characterized not only by a modest indicator of charge cycles, but also by the inevitable loss of the usable cell volume.