In winter, the battery life is greatly reduced, and electric vehicles become "electric dads". Is lithium iron phosphate really reliable?

There are only a few days left before 2021. The "New Year's Eve cold wave" is coming. Many places across the country have issued yellow warnings. I believe that many friends in the northern regions have already felt the breath of severe winter. This cold wave weather has a wide impact range, drastic temperature drops, low temperatures, and long-lasting strong winds. Most parts of the country will experience the coldest weather since the beginning of winter.

The arrival of the cold wave is undoubtedly "adding insult to injury" for many owners of new energy vehicles. Recently, many owners of pure electric vehicles have reported on online platforms that their vehicles will have varying degrees of shortened battery life, slower charging speeds, and inability to charge in the low temperatures of winter.

Therefore, many netizens joked: Electric cars in winter need to be taken care of like a father.

I wonder how many people still remember the NIO owner who dared not turn on the heater last winter. Once the heater was turned on, the battery life plummeted, and driving in a down jacket was a helpless move. The main reason for the reduction in battery life of pure electric vehicles in winter is the battery. At present, most pure electric products are equipped with ternary lithium battery packs. At low temperatures, the activity of lithium ions in the battery will be greatly reduced, and the electrolyte will become viscous, which will lead to a decrease in battery capacity.

However, compared with the reduced battery life of ternary lithium batteries, the battery life problem of lithium iron phosphate, which has been a hot topic recently, seems to be more serious.

At the end of October this year, the first batch of domestically produced Model 3 equipped with Ningde Times lithium iron phosphate batteries began to be delivered. The new car is equipped with a 55kWh lithium iron phosphate battery pack and has a NEDC range of 468 kilometers, which is 22 kilometers longer than the previous ternary lithium battery version. Tesla's price cuts and range increases seem to be "really good", but after entering winter, many Model 3 owners who just picked up their cars have experienced a serious reduction in low-temperature range.

According to feedback from netizens, the lithium iron phosphate version of Tesla Model 3 shows a range of 420 kilometers when fully charged in winter, but after actually traveling 241 kilometers, only 5% of the battery power remains. The gap is even more serious than the previous ternary lithium battery version of Model 3.

Why does the battery life of lithium iron phosphate batteries decline more seriously than that of ternary lithium batteries at low temperatures? In fact, this is due to the difference in the material structure of lithium iron phosphate. The ternary material is nickel, cobalt and manganese, arranged in a layered structure, but lithium iron phosphate uses an octahedral olivine structure, so lithium iron phosphate batteries will have better stability performance, and the battery capacity decline is more controllable.

However, the difference in structure also leads to a lower capacity of lithium iron phosphate batteries. It is very easy for ions to migrate in the hierarchical structure of ternary lithium, but during the migration process of octahedrons, there is greater resistance, lower activity, and the power is more easily affected by the external temperature environment.

The capacity retention rate of lithium iron phosphate batteries is about 60-70% at 0°C, decays to 40-55% at minus 10°C, and only remains 20-40% at minus 20°C.

However, ternary lithium batteries can still maintain about 70%-80% of the normal battery capacity at -20℃, which is why the range of vehicles equipped with lithium iron phosphate batteries is more severely reduced in winter.

Of course, Tesla has recently announced a solution through official channels: through software upgrades, the preheating function of lithium iron phosphate models has been optimized along the way. When using the large screen to navigate to a super charging station/third-party DC charging station, the vehicle will preheat the battery during driving. Before starting charging, let the battery reach an ideal temperature close to the activity of lithium electrons to improve charging efficiency and speed.

I just don’t know whether such a software upgrade can really solve the battery life problem of the lithium iron phosphate version of Model 3.

Coincidentally, BYD Han EV, a new hit in the domestic pure electric market, is also equipped with a lithium iron phosphate battery pack, and has recently been exposed to have a reduced range in winter, becoming the focus of media and consumers.

Recently, a BYD Han EV owner revealed that after driving 230 kilometers on a full charge, the battery power of the mid-range BYD Han EV he purchased was only 5%, which is nearly two-thirds of the 605-kilometer range displayed on the meter. The owner charged the car three times in total after picking it up, but the cumulative mileage was only 744 kilometers, which is significantly different from the official nominal range data.

As a new domestic product that has been on the market for less than 5 months, BYD Han's sales performance is indeed eye-catching. In November, its sales have exceeded 10,000 units, of which Han EV's sales reached 7,482 units, making it the "leader" of China's pure electric vehicles. If it were not limited by the current insufficient production capacity, I believe Han's sales would still have a lot of room for growth. I just don't know whether this winter range reduction incident will affect BYD Han's subsequent sales.

Finally: In the short term, the problem of pure electric vehicle's range reduction in winter is still "unsolvable". It is undeniable that pure electric vehicles have many advantages such as strong power, high intelligence, and assisted driving, but do users have to accept the shortcomings of reduced range in winter? Perhaps manufacturers should inform users of the vehicle's low-temperature range problem when promoting the model, rather than waiting until winter comes to regret buying an "electric dad" home.

Given the same budget, would you choose a traditional fuel vehicle or a new energy vehicle? Please leave your opinion.