Most people are not aware that batteries really are everywhere around us. They give life to almost every single device we use, from the alarm clock in the morning to the Netflix series displayed on our laptop in the evening. And our crave for batteries ramp up day after day, as electric vehicles are steadily making progress on the international stage. With this unquenchable thirst for batteries, there is little wonder that the battery industry itself has developed over the decades and gave birth to several battery generations. Given the simplicity of the basic functioning principle, different combinations of materials and designs were plenty.
Now is a time of transition in the battery environment; dinosaurs are competing against youngsters. Honorable lead-acid batteries are facing a serious challenger in the form of emerging lithium-ion batteries. When considering investing in a battery backup system, it might be useful to refer to some guidelines regarding the current state of battery technology.
Lead-acid batteries versus Lithium-ion batteries: which technology shall prevail in the telecommunications battlefield? Let’s break it down, step by step.
Lead-acid batteries are the patriarch of the battery family. Invented as early as 1859, this first-of-its-kind rechargeable battery became the absolute standard for any applications. Needless to say that over the span of a century, lead-acid batteries manufacturers have had enough time to set up a mature and cost-efficient industry. Combining lead plates and sulphuric acid proved over the years to be a reliable recipe for power supply and this statement is still valid today since lead-acid batteries are currently the most widely used kind of rechargeable batteries in the world.
At the other side of the spectrum, lithium-ion batteries first saw the light of the day in the late 70s and were not commercialized until 1991. At first, lithium-ion batteries were used for smaller-scale applications such as cell phones or laptops, but in recent years their usage for larger-scale applications (notably electric cars) gained a lot of attention. In that perspective, telecommunications could potentially represent a viable market for lithium-ion batteries.
Lithium-ion has a far greater performance over lead batteries in most aspects.
To begin with, its energy density is 3 times the one of lead-acid batteries, giving lithium-ion technology a significant edge when it comes to large-scale applications (simply fewer batteries would be required). The cycle life of a lithium-ion battery is also significantly higher than its lead-acid counterpart, since lead-acid batteries rarely go beyond 500 cycles whereas an average lithium-ion battery performs well after 1000 cycles (Note: a cycle life is the number of complete charge/discharge cycles that a battery is able to support before its performance is reduced, it is a good indicator of a battery’s lifetime).
Additionally, the “useable capacity” of lead-acid batteries is rather limited; in fact, only 50% of the capacity can be used without severely damaging the battery, while lithium-ion battery usable capacity revolves over 85%. To put that in perspective, consider two 1000 amp/hour battery banks, one using lead-acid and the other lithium-ion. The real capacity provided by the lead-acid one would be in practice only 500 while the one using lithium-ion would deliver 850.
It must also be added that charging lithium-ion batteries is faster and more efficient than charging lead-acid ones. Most lithium-ion batteries can charge within an hour, while lead-acid batteries may take up to 10 hours to fully charge safely.
Last but not least, Lithium-ion batteries are way less affected by outdoor conditions than lead-acid ones. Under very hot temperatures, lead-acid batteries would degrade much quicker than lithium ion-ones, which can be a significant downside in the telecommunications field in many geographic areas. All in all, lead-acid batteries require frequent maintenance operations and replacements (because of their poor lifetime and resistance), which is not so much the case for lithium-ion batteries which are truly maintenance-free.
The only area where lead-acid batteries have a performance edge over lithium-ion batteries are in terms of power in very cold temperatures. This is mostly the reason why they are still used to start most gasoline car engines.
Lead-acid batteries take revenge in the cost department. All performance benefits of lithium-ion come at a high price, usually 2 to 5 times higher. This is due to the fact that lead-acid batteries have been manufactured for over a hundred years in a high volume, and competition has driven down the price to under 100$/kWh. With Lithium-ion comes more complexity. Lithium cells need more electronic and mechanical protections than lead. Although the cost of cells has fallen down under 150$/kWh, when put in an electrically and mechanically safe packaging, they can cost from 200$/kWh to 1000$/kWh. On top of that, the lithium-ion technology relies on expensive raw materials, such as cobalt ($60/kg and prices are only going up). That being said, the lithium-ion technology is still relatively young as an industry and we can expect economies of scale and technological improvements in the years to come. In fact, upfront costs have already begun to decrease (see figure below) and operating costs are well under those of lead-acid batteries, given their shorter lifespan and performance.
Since the end of the 90s, newspapers periodically report spectacular failures of lithium-ion batteries. Such was the case for instance for the Samsung Galaxy S7, whose commercialization had to be stopped after some devices caught fire or even exploded. It gave birth to the belief that lithium-ion batteries were more powerful but at the same time more dangerous than other batteries.
Although there is some scientific ground for that reasoning, this statement is far from reality. The root of the problem here is short circuits, which result in overheat for the battery and can ignite its components. In that perspective, the difference between lead-acid and lithium batteries is that the electrolyte ( Note: the ionic conductive substance that separates the anode from the cathode) of lithium-ion batteries is flammable whereas the one of lead-acid batteries is water. This means that lead-acid batteries are more immune to fire outbreaks.
However, this is not mentioning the safety components that exist within a lithium-ion battery. In fact, electronic protection circuits secure the device by limiting the risk of short circuits and providing mitigation mechanisms in the event of an increase in temperature or pressure. Lead-acid batteries for their part are not safeguarded from short circuits and spillage of the sulphuric acid contained in the lead-acid battery would prove as disastrous as any explosion.
If you think of it, the fact that explosions of lithium-ion batteries always make the headlines is in truth a good indicator of how rare and unexpected these events really are.
Lead-acid batteries’ ecological footprint is a significant source of concerns since they utilize a lot of raw materials only to deliver mediocre outputs. The lead processing industry also necessitates huge amounts of energy and produces a great deal of pollution as a result. This is not even mentioning the fact that lead is known to be particularly detrimental to human and animal health.
This is not to assess that lithium-ion batteries are without environmental preoccupations (especially regarding the mining process), but their superior performances make them more acceptable than lead-acid ones. They are also high hopes regarding the lithium-ion recycling industry which is expected to mimic and rival the already established lead acid recycling branch.
All the aforementioned dimensions should not overshadow practical considerations which do matter when thinking about installing battery banks. The footprint, the weight, the shape or even the possibilities for customization may not be senseless thoughts at all. In that perspective, the lithium-ion technology does it better once again. Lithium-ion batteries weight only a third than their lead-acid counterparts and take up less space as well (which, by the way, is especially relevant when talking about backup power). As a result, lithium-ion batteries are more easily placable and fit in more diverse environments than more cumbersome and out fashioned lead-acid batteries.
And the winner is…
Lithium-ion batteries come out quite clearly as the winners of the comparison with their lead-acid predecessors. They perform simply better, taking advantage of technological improvements to address lead-acid batteries’ shortcomings. They are also less impactful on the environment and easier to blend in any landscape. Lead-acid batteries are not completely out of the picture though, since they offer a lower initial investment, remain cheaper and easily available in comparison with lithium-ion batteries, but these advantages are becoming less and less relevant as the lithium-ion industry is maturing up. Lithium-ion batteries can realistically be considered well-suited for large-scale applications such as telecommunication sites, all the more since technological innovations are on sight (lithium-air batteries could prove even more efficient in the future). Keep in mind that lithium-ion batteries can still be refined by implementing a remote management system, like the one featured in Autonom’s batteries.