Today, almost everyone has a phone (smartphone, camera phone, tablet) in their pocket that can outperform your home desktop, which you havenβt updated for several years. In every gadget you have a lithium-polymer battery. Now the question is: which of the readers will remember exactly when the irrevocable transition from dialers to multifunctional devices took place?
Difficult... You have to strain your memory, remember the year you bought the first "smart" phone. For me, this is approximately 2008-2010. At that time, the capacity of a lithium battery for an ordinary phone was about 700 mAh, now the battery capacity of phones reaches 4 mAh.
An increase in capacity by 6 times, despite the fact that, roughly speaking, the size of the battery has increased only 2 times.
Like us , lithium-ion UPS solutions are rapidly conquering the market, have a number of undeniable advantages and (Especially in a server room).
Friends, today we will try to understand and compare solutions based on iron-lithium-phosphate batteries (LFP) and lithium-manganese (LMO), study their advantages and disadvantages, and compare them with each other in a number of specific indicators. Let me remind you that both types of batteries are lithium-ion, lithium-polymer batteries, but differ in chemical composition. If you are interested in continuing, please under cat.
Perspectives of lithium technologies in the field of energy storage
The current situation in the Russian Federation for 2017 was as follows.
Using the source: βThe Concept for the Development of Electricity Storage Systems in the Russian Federationβ, Ministry of Energy of the Russian Federation, August 21, 2017.
As you can see, lithium-ion technology at that time was at the forefront of approaching industrial production technology (primarily LFP technology was meant).
Next, let's look at trends in the US, or rather, consider the latest version of the document:
Reference: ABBM - energy arrays for uninterruptible power supplies, which are used in the electric power industry for:
- Reservation of electricity for critical consumers in case of interruptions in the auxiliary power supply (SN) 0,4 kV at the substation (SS).
- As a "buffer" drive for alternative sources.
- Compensation for power shortages in the peak consumption mode to unload electricity generation and transmission facilities.
- Accumulation of energy during the day during its low cost (night time).
As you can see, Li-Ion technologies, as of 2016, firmly held the leading position and showed rapid multiple growth in both power (MW) and energy (MWh).
In the same document we can read the following:
βLi-ion technologies represent more than 80% of the added power and energy generated by ABBM systems in the US at the end of 2016. Lithium-ion batteries have a highly efficient cycle (charge, author's note) and release stored power faster. In addition, they have a high energy density (power density, author's note) and high recoil currents, which led to their choice as batteries for portable electronics and electric vehicles.
Let's try to compare two technologies of lithium-ion batteries for UPS
We will compare prismatic cells built on the chemistry of LMO and LFP. It is these two technologies (with variations of the LMO-NMC type) that are now the main industrial designs for various electric vehicles, electric vehicles.
A lyrical digression about batteries in electric vehicles can be read here.Ask, what does electric transport have to do with it? Let me explain: the active distribution of electric transport on Li-Ion technologies has long crossed the stage of prototypes. And as we know, all the latest technologies come to us from expensive, newest areas of life. For example, a lot of auto technologies came to us from Formula 1, a lot of the latest technologies entered our life from the space sector, and so on ... Therefore, in our opinion, lithium-ion technologies are now penetrating industrial solutions.
Consider a table comparing the main manufacturers, battery chemistry and the actual automotive companies that are actively producing electric vehicles (hybrids).
We will select only prismatic cells that are suitable for the form factor of use in the UPS. As you can see, lithium titanate (LTO-NMC) is an outsider in terms of specific stored energy. There remain three manufacturers of prismatic cells suitable for use in industrial solutions, in particular in batteries for UPS.
I will quote and translate from the document βLife cycle assessment of long life lithium electrode for electric vehicle batteries- cell for LEAF, Tesla and VOLVO busesβ (Original βLife cycle assessment of long life lithium electrode for electric vehicle batteries- cell for LEAF, Tesla and Volvo bus" from December 11, 2017 by Mats Zackrisson. Here, the chemical processes in the batteries of vehicles, the impact of vibrations and climatic conditions of operation, environmental damage are mainly investigated. However, there is one curious phrase regarding the comparison of two lithium-ion battery technologies.
In my free translation it looks like this:
NMC technology shows a lower environmental impact per kilometer driven than LFP technology with a battery cell metal anode, but it is difficult to reduce or eliminate errors. The bottom line is that the higher energy density of the NMC means less weight and thus less power consumption.
1) Prismatic cell LMO technology, manufacturer , cost $400.
Appearance of the LMO cell
2) Prismatic cell LFP technology, manufacturer , cost $160.
External view of the LFP cell
3) For comparison, let's add an aircraft backup battery built on LFP technology and the one that participated in the sensational scandal , manufacturer of True Blue Power.
TB44 Battery Appearance
4) For objectivity, let's add a standard UPS battery
The appearance of a classic UPS battery
Let's put the initial data in a table.
As you can see, indeed, LMO cells have the highest energy efficiency, classical lead loses at least twice in specific energy.
It is clear to everyone that the Li-Ion battery array BMS system will add mass to this solution, i.e., reduce energy density by about 20 percent (the difference between the net weight of the batteries and the complete solution, taking into account BMS systems, module shell, battery cabinet controller). The mass of jumpers, battery switch and battery cabinet is conditionally equal for lithium-ion batteries and battery array of lead-acid batteries.
Now let's try to compare the calculated parameters. In this case, we take the depth of discharge for lead - 70%, and for Li-Ion - 90%.
Note that the low specific energy for an aircraft battery is due to the fact that the battery itself (which can be considered as a module) is enclosed in a metal fireproof casing, has connectors and a heating system for operation at low temperatures. For comparison, a calculation is given for one cell in the TB44 battery, from which it can be concluded that the characteristics are close to those of a conventional LFP cell. In addition, the aviation battery is designed for high charge / discharge currents, which is associated with the need to quickly prepare the aircraft for a new flight on the ground and a high discharge current in the event of an emergency on board, for example, loss of on-board power
By the way, here's how the manufacturer compares different types of aircraft batteries
As we can see from the tables:
1) The capacity of the battery cabinet in the case of LMO technology is higher.
2) The number of battery cycles for the LFP is longer.
3) The specific gravity for LFP is less, respectively, with the same capacity, the battery cabinet based on iron-lithium-phosphate technology is larger.
4) LFP technology is less prone to thermal runaway due to its chemical structure. As a result, it is considered relatively safe.
For those who want to visually understand how lithium-ion batteries can be connected to a battery array to work with a UPS, I recommend looking here.For example, such a scheme. In this case, the net weight of the batteries will be 340 kg, the capacity will be 100 Ah.
Or a diagram for the LFP 160S2P, where the net weight of the batteries will be 512 kg, and the capacity will be 200 ampere-hours.
CONCLUSION: Despite the fact that batteries with iron-lithium-phosphate (LiFeO4, LFP) chemistry are used mostly in electric vehicles, their characteristics have several advantages over the LMO chemical formula, allow high current charging, and are less susceptible to thermal runaway. Which battery type to choose is up to the end-to-end solution provider, who determines this based on a number of criteria, not least the cost of the battery array as part of the UPS. At the moment, any type of lithium-ion batteries still loses in terms of cost to classical solutions, but the large power density of lithium batteries per unit mass and smaller dimensions will increasingly determine the choice towards new energy storage devices. In some cases, the lower gross weight of the UPS determines the choice towards new technologies. This process will be completely invisible, and is currently being held back by high costs in the low price segment (consumer solutions) and the inertia of lithium fire safety thinking among customers who are looking for the best UPS options in the industrial UPS segment with a capacity of more than 100 kVA. The level of the middle power segment of UPS from 3 kVA to 100 kVA is possible for implementation on lithium-ion technologies, but due to small-scale production it is quite expensive and loses to ready-made serial samples of UPS on VRLA batteries.
To learn more and discuss a specific Li-Ion battery solution for your server room or data center, please send an email request. or by making a request on the company's website .
OPEN TECHNOLOGIES β reliable integrated solutions from world leaders, adapted specifically to your goals and objectives.
Author: Kulikov Oleg
Lead Design Engineer
Department of Integration Solutions
Open Technologies Company
Source: habr.com