LFP degenerates just 1% in year 3 - SOH 91% after 80,000 km, EV buyers should know ⚡

LFP degenerates just 1% in year 3 - SOH 91% after 80,000 km, people buying EVs should know.

This figure goes against what many people have always believed about EV batteries. The 60 kWh LFP battery-powered Tesla Model Y ran 80,000 kilometers, charged mainly through a Supercharger, and found that the SOH or battery health at year 3 was 91%. This sounds good, but more interesting is that the details behind year 2 had deteriorated by 8% at once, but in year 3, the number was almost stationary, deteriorating by only 1% throughout the year. The chart that should have gone down continuously turned flat, and that's what engineers know about the battery. It's been a long time, but most EV buyers still don't know.

The number one fear of people considering buying an EV is that the battery is degraded. The most common question on Facebook and Pantip is that it is often fast charging. Is the battery broken quickly? If there is no charging point at home, rely on the DC Fast Charge every day. How long will the battery last after three years, running 80,000 kilos? How much will the battery have?

The figure from the Tesla Model Y test that ran 80,000 kilometers charging a Supercharger essentially answered these questions. In Year 2, SOH went down to 92%. It means that 8% of the batteries were degraded on the day of purchase. This figure shocked many who saw the graph at first because it seemed that the batteries were degenerating quickly. But by the third year of use, SOH was 91%, only 1% degenerated throughout the year. At the same time, there was data from a car that had already run 178,600 kilometers, charging through DC Fast Charge almost 100% over its lifetime. The result is that SOH is still 92%, which is barely equal to almost half of cars running less.

What do these numbers tell? And why is it so important for people who buy EVs in Thailand today?

First of all, you need to understand what SOH is. SOH stands for State of Health or Battery Happiness. It's a number that says, as of now, how much energy does this battery store compared to when it's new? 100% SOH means that it's still brand new. It stores full power according to the manufacturer. 91% SOH means that the battery stores 91% of its new episode capacity. If that car has a new 60 kWh battery (kWh is a power unit, it's easy to say that 60 kWh runs about 400 kilos in normal weather), when SOH has 91% left. It will actually store about 54.6 kWh of energy, or run about 360 kilos instead.

Later is the difference between LFP and NMC, which is at the heart of this. LFP stands for Lithium Iron Phosphate or Battery Lithium Iron Phosphate. It is a battery technology that uses iron as the main component instead of rare metals. NMC stands for Nickel Manganese Cobalt or BATNICK Manganese Cobalt. That uses cobalt and nickel, which are much more expensive. The main difference is not in the mixture alone, but in the chemical behavior when charged and emitted repeated current.

LFP has a more stable crystal structure. When lithium ions move in and out between the positive and negative terminals in the process of charging and use, the structure does not expand or shrink much, causing less damage to accumulate than NMC. The structure expands more when charged fast and hot. And that explains why charging with DC Fast Charge or Fast Direct Charge, which emits high current in a short time, clearly affects the NMC more than the LFP. The heat and pressure generated during fast charging causes the NMC structure to deteriorate faster, while the LFP tolerates significantly better.

Now let's explain why the degradation curve, or the deterioration graph of the LFP, is not linear. In the first part of its lifetime, the surface of the electrodes in the LFP battery forms a thin film called SEI (Solid Electrolyte Interphase). This film is caused by the chemical reaction between the electrolyte and the negative pole in the first cycle of charging. This process uses some energy and causes a relatively early decline in SOH. But once SEI is fully formed, it acts as a protective layer, slowing down the deterioration in the next phase significantly. That explains why year 2 is deteriorating so fast, and then year 3 is back. Slow down, almost stand still.

Three sets of figures derived from the actual test tell this story very clearly.

The first series is a Tesla Model Y car based on a CATL-based LFP battery of about 60 kWh. It runs a total of 80,000 kilometers, charging mainly Superchargers throughout the second year. SOH is 92%. But in the third year, SOH is only 91%. Total is only 9% degenerate from the day of purchase, even almost always charging fast.

The second series is another Tesla Model Y that has already run 178,600 kilometers, which exceeds twice the first car and charges nearly 100% DC Fast Charge over its lifetime. The result is that SOH is still 92%. This means that cars that run twice as fast and almost always charge have battery health equivalent to cars that run much less. This figure is very important for people who do not have a charging point at home and rely mainly on DC Fast Charge.

The third set is a comparison of the old NMC at the same distance, about 178,000 kilometers. The SOH of the NMC is 79%, compared to 92% of the LFP. The difference is 13% in the same distance. It sounds numerical, but in practice it means that the NMC with 82.8 kWh batteries. The new episode has a real capacity of 65.4 kWh, while the LFP with a smaller battery with 92% SOH can still maintain a better run distance in the long run. And there is one notable case: the 82.8 kWh NMC Long Range, a 52% fast charger and 48% home charger. In the first 6 months, SOH was still 99%, but that was only 6 months. Before the SEI process fully formed and the graph began to clearly show the difference of the two technologies.

For Thais who are considering buying EVs, this information is directly related because most EVs sold in Thailand today use LFP batteries. Tesla Model Y sold in Thailand uses LFP batteries from CATL, as well as all BYD test vehicles sold in Thailand. Dolphin, Atto 3, Seal uses LFP batteries as BYD's Blade Battery. MG4 Electric and MG ZS EV also use LFP, and Haval H6 HEV, as well as some EV models of GWM, are based on LFP technology.

The point to be aware of is the hot weather in Thailand. High temperature is one of the factors that causes batteries to deteriorate faster for all technologies. The test data cited comes from a climate that may differ from Thailand, which has an average temperature above 30 degrees Celsius throughout the year. Heat triggers chemical reactions within the batteries slightly faster, resulting in a loss of capacity accumulation. However, LFP is better at heat resistance than NMC anyway because its chemical stability is higher and the temperature of explosion or fire in LFP is significantly higher than NMC.

For infrastructure charging in Thailand, DC Fast Charge points are also concentrated in Bangkok and major cities. If you travel frequently in the provinces, check the charger map before you decide to buy a car with a small battery. Because the limited running distance per charging cycle may be inconvenient. But if you use a car in the city, this data clearly confirms that LFP is very resistant to repeated fast charging.

The straight answer for people who are making decisions. If you use a car in the city, rely mainly on the DC Fast Charge because there is no charging point at home. And considering an EV that uses an LFP battery, such as the Tesla Model Y, all BYD models, or MG4. The data from the actual test says you don't have to be afraid of it. The LFP battery is designed to withstand repeated fast charging, and after the first two years of deterioration, the graph will flatten and SOH will stabilize.

There are three things to do to maintain SOH for a long time. First, do not charge 100% every day. Set the charge at 80-90% for normal use. Keep 100% charging for days that need to travel long distances. Second, avoid often leaving the battery below 10%. The best SOC range for LFP is 20-80%. Third, if parking in a hot outdoor, avoid charging for a long time after full charging. Because heat combined with high SOC for a long time accelerates deterioration.

What needs to be watched in the next phase is the actual SOH data from BYD vehicles sold in Thailand in the long run. Currently, there is no official SOH data release from Thai vendors, whether BYD, MG or Tesla. What is available is data from international users whose weather is different from Thailand. Reliable Thai data will come from the user community that measures SOH themselves through the application of each brand.

Besides that, the battery warranty is another point to check before buying BYD. The battery warranty is 8 years or 160,000 kilometers, with the SOH warranty not lower than 70%. Tesla has 8 years or 192,000 kilometers of battery warranty. Depending on the model, MG indicates a battery warranty of 8 years or 150,000 kilometers. These figures are the minimum safety net guaranteed by the manufacturer, but based on the actual data acquired, LFP seems to have done significantly better than the figures in the warranty contract.

Finally, BOI and battery testing standards in Thailand. There are signs that the relevant authorities are considering setting SOH standards for EV vehicles sold in the country. This will give buyers in Thailand the same benchmark comparisons instead of relying solely on foreign data as they are now. If the standard is applicable, it will significantly change the way Thai people decide to buy EV vehicles.

# Electric train # WelldoneGuarantee # EV Thailand # Tesla # LFP# Batteries # BYD