The Pros and Cons of Lithium Batteries
Pioneer work with the lithium battery began in 1912 beneath G.N. Lewis but it was not till the early 1970s when the first non-rechargeable lithium batteries became commercially available. Lithium is the lightest of all metals, has the best electrochemical potential and gives the most significant energy density to weight.
Attempts to develop rechargeable lithium batteries failed due to safety issues. Because of the inherent instability of lithium metal, especially during charging, research changed to some non-metallic lithium battery using lithium ions. Although slightly lower in energy density than lithium metal, lithium is secure, provided certain precautions are met when charging and discharging. In 1991, the Sony Corporation commercialized the first lithium ion battery.
The energy density of lithium ion is generally double that of the typical nickel-cadmium. There is potential for greater energy densities. The loading characteristics are reasonably good and act similarly to nickel-cadmium in terms of discharge. The high cell voltage of 3.6 volts enables battery pack designs with only 1 cell. Nearly all of today’s cell phones operate on a single cell.
Lithium-ion is a low maintenance battery, an advantage that much other chemistry cannot claim. There isn’t any memory and no scheduled cycling must extend the battery’s life. In addition, the self-discharge is less than half in comparison to nickel-cadmium, making lithium-ion ideal for modern fuel gauge applications. Lithium-ion cells cause little harm when disposed.
Despite its general advantages, lithium-ion has its drawbacks. It’s fragile and requires a protection circuit to maintain safe operation. Additionally, the cell temperature is monitored to prevent temperature extremes. With these measures in place, the chance of metallic lithium plating happening due to overcharge is practically eliminated.
Aging is an issue with the majority of lithium-ion batteries and many manufacturers stay silent about this situation. Some capacity deterioration is noticeable after one year, whether the battery is in use or not. The battery frequently fails after a couple of decades. It ought to be said that other chemistries also have age-related degenerative effects. This is especially true for nickel-metal-hydride if subjected to high ambient temperatures. At exactly the same time, lithium-ion packs are known to have served for five years in some programs.
Manufacturers are constantly improving lithium-ion. New and improved chemical combinations are introduced every six months or so. With such rapid progress, it is difficult to assess how well the revised battery will era.
Storage in a cool place slows the aging process of ion (as well as other chemistries). Moreover, the battery should be partly charged during storage. The manufacturer recommends a 40 percent charge.
The most economical lithium-ion battery concerning cost-to-energy ratio is that the cylindrical 18650 (size is 18mm x 65.2mm). This cell can be used for mobile computing and other applications that do not demand ultra-thin geometry. If a slender pack is required, the prismatic lithium-ion cell is your best alternative. These cells come in a greater cost in terms of stored energy.
Lithium technology has become well known and known for powering small electronics like laptops or cordless tools, and has become increasingly common in these programs — edging out the elderly NiCad (Nickel-Cadmium) rechargeable battery chemistry due to lithium’s many advantages.
But as you might remember from the many news reports a few years back around faulty notebook batteries bursting into flame — lithium ion batteries also got a reputation for catching fire at a very dramatic fashion. The widely used lithium ion battery formula had been Lithium-Cobalt-Oxide (LiCoO2), and also this battery chemistry is prone to thermal runaway when the battery is ever accidentally overcharged. This could lead to the battery placing itself on fire — and a lithium fire burns hot and fast.
This is among the reasons which Up until lately, lithium was rarely utilised to create large battery banks.
But in 1996 a new formulation for Mixing lithium ion batteries has been designed — Lithium Iron Phosphate. Known as LiFePO4 or LFP, these batteries have a slightly lower energy density but are intrinsically non-combustable, and thus vastly safer than Lithium-Cobalt-Oxide. And once you think about the advantages, Lithium-Ion batteries become exceedingly tempting.
1-Superior “Useable” Capacity
It is considered practical to regularly use 90 percent or more of the rated capability of a lithium battery bank, and occasionally more. Consider a 100 amp hour Battery — if it had been lead acid you would be wise to use just 30 to 50 amp hours Of juice, but with lithium you could tap to 90 amp hours or even 100Ah (100% DoD).
2-Extended Cycle of Life
Laboratory results indicate that you could expect to see 2000 to 5000 cycles out of a well cared for Lithium Iron Phosphate battery bank. Both C-Rate and Depth of Discharge (DoD) influence expected lifespan. Some recent measurement proves that a LFP battery will still provide more than 80% of it’s potential after 2000 cycles at 100% DoD as well as 5000 cycles at 65% DoD. All these tests are finished in 1C-Rate Cycles.
These cycle life results are much Greater than NMC or NCA chemistries, massively used in electric vehicle industry.
In contrast, even the best deep cycle lead acid Batteries are generally only great for 500-1000.
3-Peukert’s Losses & Voltage Sag Virtually Non Existent
The release curve of lithium batteries (particularly relative to lead acid) is essentially flat — meaning that a 20% charged battery will be supplying almost the exact same output voltage within an 80% charged battery. This prevents any issues brought on by the “voltage sag” common to lead acid as they release, but does imply that any battery generator or monitor auto-start dependent upon voltage levels will likely not function well at all when monitoring a lithium ion bank.
Another enormous benefit of lithium batteries is that Peukert’s losses are essentially non-existent. This means that Lithium-Ion batteries can deliver their full rated capacity, even at large currents. Whereas lead acid may see up to a 40% reduction of capacity at high loads. In practice, this usually means that Lithium-Ion battery banks are very well suited to powering high current loads like an air conditioner, a microwave or a induction cook top.
4-Fast & Efficient Charging
Lithium-ion batteries may be “fast” charged to 100% of capacity. Unlike with direct acid, there is not any demand for an absorption phase to get the last 20% saved. And, if your charger is strong enough, lithium batteries can also be charged remarkably quickly. If you can provide enough charging coils — you can actually fully charge a lithium ion battery just 30 minutes.
However, even if you don’t manage to fully top off to 100 percent, no worries — unlike with lead acid, a failure to frequently fully charge Lithium-Ion batteries do not damage the batteries.
This give you lots of flexibility to tap into energy sources whenever it is possible to get them without stressing about needing to perform a full charge regularly. Several partly cloudy days with your solar system? No problem that you can’t top off until the sun goes down, as Long as you are keeping on top of your needs. With lithium ion, you can charge up what you can rather than worry about departing your battery life undercharged.
5-Very Little Wasted Energy
It is efficient at storing electricity than lithium ion batteries. Lithium batteries bill at nearly 100% efficiency, compared to the 85% efficiency of most lead acid batteries.
When charging through solar, when you are trying to squeeze as much efficiency out Of each amp as possible until the sun goes down or gets covered up by clouds. Theoretically, with lithium ion virtually every drop of sunlight you are able to collect goes into your own batteries. With restricted storage & roof space for panels, this become very essential in optimizing every square inch of wattage you’re Able to mount.
Lose their capacity in cold environments. As you can see in the diagram below, Lithium-ion batteries are much more effective at low temperatures. Moreover, the release rate affects the performance of lead acid batteries. At -20°C, a Lithium battery that delivers a 1C current (one times its capability), can provide More than 80 percent of its energy when the AGM battery will deliver 30% of its capacity. For harsh environments (hot and cold), Lithium-Ion is the Technological option.
7- Fewer Placement Issues
Lithium-ion batteries do not have to be stored upright, or in a vented battery compartment. They’re also able to fairly easily be assembled into strange shapes — an advantage if you are trying to squeeze as much power as you can into a little compartment. This is especially useful if you have an current battery bay that is restricted in size, however you want or need more power than direct acid is presently able to supply.
8-Zero maintenance requirements
Lithium-Ion batteries are rather maintenance free. A “balancing” procedure to make sure all of the cells in a battery charge are equally billed is automatically achieved by the BMS (Battery Management System). Just charge you battery and you are good to go.
While less of an issue in the large-scale solar area, LiFePO4 batteries acceptable for RVS are transported only by a couple of specialized battery sellers, and by some providers of battery charging equipment. There’s a substantial shortage of overall expertise in this area — including by many car electricians and battery vendors in general.
2-PERFORMANCE REALITY CHECK
Exaggerated claims for functionality are now less common, but unrealistic comparisons with AGM batteries continue to be made (particularly for big RV systems). For impartial and knowledgeable information talk to sellers who sell equally LiFePO4 and AGM batteries (a few exist in Australia).
LiFePO4 batteries must have a management system. Unlike traditional Batteries, LiFePO4 batteries should have their respective (nominally 3.2 volt) Cells both charged, and charge voltage and current retained within safe limits. This system may be built inside the battery, be outside — or not supplied at all. Without that system that the battery will probably quickly be wrecked.
LiFePO4 batteries must never be 100% discharged. Doing so can cause you or More cells to reverse its polarity. Some vendors claim this can be fixed. Others say it can’t.
Right now, no LiFePO4 battery (known to me) is actually an immediate and universal drop-in replacement for present conventional RV batteries. Some (such as Fusion) are close but can’t necessarily be relied on to work closely with the existing charging system. When buying, buy both the battery and the charger in precisely the same vendor. Or have that seller affirm in writing that the units are compatible.
6-COMMERCIAL OR DIY?
LiFePO4 batteries with management systems from known sellers price three/four times that of traditional batteries of comparable (claimed) capacity. The (12-volt) types used in RVs normally consist of four cells at a common housing. These cells (and the obligatory management methods) can be bought for under half the cost of fully-made up systems. Assembly demands experience, but many seemingly do this successfully.
7-LIFEPO4 PRICING CAN BE CURIOUS
Checking suggests that many apparently identical products (badging apart) are marketed at prices that may vary three or more occasions. This is considered to Be since some pass through several phases of supply, with each adding a mark-up. (I can’t comment further re this).