Part 1: Chinese, European, American or Korean electric cars – which ones have the longest-lasting batteries?

The battery – the most important component in a modern electric vehicle A decade ago, the main question when buying an electric vehicle was whether the range would be sufficient for everyday needs. Today, the situation is different. Modern electric vehicles offer a range of between 350 and over 700 kilometers on a single charge, and consumers’ attention is increasingly focused on another key factor – the life of the electric vehicle battery. The battery is the most expensive component in an electric vehicle. Depending on the model and its capacity, its value can represent between 25 and 45% of the price of the car. Therefore, more and more buyers are interested in how many years it will last, what its degradation is and whether expensive repairs or replacement will be required. In recent years, Chinese manufacturers have made a huge technological leap. Companies such as BYD and CATL are already developing batteries that are used not only in Chinese cars, but also in models from BMW, Mercedes-Benz, Tesla, Volkswagen, Volvo and other global manufacturers. This shows that quality no longer depends solely on the country of origin, but on the technology and engineering solutions used. What is an electric vehicle battery? Unlike the traditional 12-volt battery, which is mainly used to start the engine and power electrical consumers, the electric vehicle battery is a high-voltage energy pack with a voltage of between 350 and 800 volts. It consists of: hundreds or thousands of lithium-ion cells; a battery management module (BMS); a cooling or heating system; multiple temperature sensors; high-voltage fuses and protection modules. All of these components work together to ensure safety, high efficiency and maximum service life.

What does “battery life of an electric vehicle” mean? Many people believe that when a battery “gets old” the vehicle stops working. This is not true. Manufacturers assume that a battery reaches the end of its normal service life when its capacity drops to around 70–80% of its original capacity. Even then, the vehicle remains fully usable, but the range per charge decreases. For example: a new vehicle with a range of 500 km; after years of operation at 80% remaining capacity, the range may be around 400 km. For most drivers, this is still sufficient for everyday use. What is battery degradation? Degradation is the natural reduction in the maximum capacity of a battery over time. The main factors that influence this process are: the age of the battery; the number of charge and discharge cycles; the frequent use of fast DC charging stations; prolonged stay at 100% charge; deep discharge to almost 0%; high temperatures; lack of effective cooling. It is important to note that degradation is not linear. Most often in the first years the decline is minimal, after which the process gradually accelerates. What is SOH (State of Health)? When buying a used electric vehicle, one of the most important indicators is SOH (State of Health). It shows what percentage of the initial capacity the battery has retained. For example: 100% SOH – battery as new; 95% SOH – practically no noticeable loss; 90% SOH – excellent condition; 85% SOH – normal condition for a car with higher mileage; below 80% SOH – more careful assessment is required. Professional SOH diagnostics are much more reliable than judging only by the mileage displayed on the dashboard.

Why can two identical cars have different battery life? This is one of the most frequently asked questions. Two completely identical electric vehicles can differ significantly in the condition of their batteries after a few years. The reasons are various: one car is mainly charged at an AC charging station; the other almost always uses ultra-fast DC chargers; one is driven in a temperate climate; the other operates year-round in very high temperatures; different driving styles; different frequency of full charging to 100%. Therefore, the same battery can have different degradation rates for different owners. What warranty do manufacturers provide? Almost all major manufacturers now offer a warranty of between 8 years or 160,000 kilometers for the high-voltage battery. The warranty usually covers cases in which the capacity drops below a certain value (most often 70%). However, it is important to know that the warranty does not mean that the battery must be replaced after eight years. In practice, many electric vehicles continue to operate reliably after this period. Why do batteries last significantly longer today? The first electric vehicles used relatively primitive battery management systems. Today, the technology is significantly more advanced. Modern BMS systems: control the temperature of each cell; balance the voltage between individual cells; limit excessive charging and discharging; monitor hundreds of parameters in real time. Thanks to these technologies, the battery life of modern electric vehicles is significantly longer compared to models from ten years ago.

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