4 Reasons for Using Lithium Iron Phosphate Batteries in Storage Systems

Since there are different applications, their energy requirements also differ. To meet these requirements, several battery compositions with different properties are available. At HIS, we mainly rely on lithium iron phosphate, known as LiFePO4 or LFP batteries. For most applications, LFP batteries are used as they are known from mobile phones, notebooks, electric cars and the like.

Within the broad category of lithium-ion batteries, the performance of the batteries varies due to the cathode material used. Lithium-ion batteries typically consist of a conductive substrate, often aluminum foil, coated with an active material to store both lithium ions and electrical current. The most common compositions of these battery cells include lithium nickel cobalt manganese (NMC), lithium nickel cobalt alumina (NCA) and lithium iron phosphate (LFP).

Safety

Safe battery solutions are a top priority, which is why we do not compromise on safety features in our battery solutions. Our battery solutions can withstand excessive temperature, current, voltage or short circuits as they have electrical/mechanical protection circuits. Compared to other LIB cell technologies, LFP technology offers more safety. In the event of a short circuit or a hit by an object that could penetrate the battery cells, most batteries will start to burn or explode. Batteries that remain stable under the above probable conditions are considered reliable for use in BESS. Many of the batteries currently available on the market do not pass this test and are therefore not suitable for use in battery storage systems.

However, in other batteries, unstable chemical and thermal cathode materials (e.g. NMC) can trigger exothermic chemical reactions within a cell. This exothermic reaction is caused by excessive heat generation due to overcharging, internal or external short circuits, contamination during production, high heat exposure or mechanical damage. The internal temperature of a cell rises when the release of thermal energy increases the reaction rate of the cell chemistry. When a certain temperature threshold is exceeded, the self-accelerating reaction becomes uncontrollable and leads to thermal runaway. This can cause the battery cell to catch fire or even explode. The situation is further exacerbated by the release of oxygen from the cathode material, making the fire extremely difficult to extinguish.

Unlike other batteries, LiFePO4 batteries never experience thermal runaway. This eliminates the risk of overheating and possible fires. With a stable temperature profile under extreme conditions, LFP batteries have stable thermal behavior (up to 300°C) and are not self-igniting (from overcharging). In NMC or NCA cells, on the other hand, a short circuit can generate a very high temperature of over 700°C, which can melt the separator and spread to other cells. This results in a fire that cannot be extinguished even underwater, as the oxygen needed for combustion is already contained in the battery material. This is why the LFP battery is the preferred choice for use in battery storage systems.

Durability & Cycle Life

When battery cells are exposed to chemical, thermal and mechanical changes, their original capacity loses a little with each charge and discharge process (duty cycle). This simply means that it stores less and less energy over time. You may also know this from your mobile phone when after 2 years even the fully charged battery only lasts half a day.

Due to the slightly lower cell voltage of 3.2V, LFP cells have a slightly lower energy density compared to NMC cells. However, this initial disadvantage is quickly outweighed by their up to ten times greater cycle stability, which offers significant long-term benefits. With each duty cycle, NMC cells age and after 2500-3000 cycles, 80 percent of their original capacity remains. This offsets the slightly higher initial cost of using lithium iron phosphate over time.

As battery demand is higher in mobile applications, LFP batteries offer longer lifetimes in portable and mobile devices. Due to the longer lifetime of battery storage systems using LFP technology in stationary applications, the relative storage cost (Levelized Cost of Storage or LCOS) over their lifetime can be reduced by up to 50% compared to NMC batteries.

Proven technology

The LFP technology used in HIS Energy solutions guarantees a specific power even when the battery is nearing the end of its life cycle. In addition, the memory effect of the LFP cells makes them superior to other LIBs. If a battery is only partially discharged frequently, this results in a loss of capacity, also known as the memory effect. The battery "remembers" the energy demand and adapts over time to only deliver the amount of energy needed for previous discharge cycles, rather than the full original capacity.

Lithium iron phosphate batteries have a high power density compared to other LIBs. This allows the LFP battery to handle charge and discharge currents along with increased pulse load capacity. With higher currents, LFP cells can be charged quickly, but constant fast charging will shorten the life of this battery. This effect of fast charging occurs to a lesser extent with LFP cells. Through intelligent system design, cost-effective solutions for stationary applications can be created that find the perfect balance between charge and discharge rates, cycle stability and lifetime. This approach helps to reduce the overall Levelized Cost of Storage (LCOS) over the lifetime of the system and ensures both efficiency and long-term value.

Environmentally friendly batteries

LFP is unique among cathode materials because its chemical composition occurs naturally as a mineral and no additional raw materials are needed for the chemical reactions. Therefore, our battery solutions do not contain cobalt or nickel, as these are toxic heavy metals with environmental impacts. In LFP cells, all the lithium is used for the chemical reaction. In contrast, other lithium-ion batteries only use about 50-60% of the lithium, as higher usage can lead to instability in the layer structure or the remaining lithium becomes part of the crystalline structure of the cathode. This efficiency reduces the amount of lithium required per kWh from about 140 grams (in NMC/NCA batteries) to about 80 grams in LFP cells.

LFP Batteries - The Safest Technology for Applications

Lithium Iron Phosphate batteries are reliable, safe and robust compared to traditional lithium-ion batteries. LFP battery storage systems offer exceptional long-term benefits with up to 10 times more charge cycles compared to LCO and NMC batteries and low total cost of ownership (TCO). They provide reliable performance with minimal maintenance, making them a solid investment that ensures both safety and long-lasting functionality.

LFP batteries are preferred due to their cycle stability, lower internal resistance, higher efficiency and wide operating temperature range. For the fastest and safest all-in-one battery solutions, HIS-Energy offers best-in-class options with their 215KW and 233KW premium batteries. Our energy solutions integrated with a battery management system (BMS) are designed for your commercial and industrial applications.