Is the voltage of electric vehicle battery the higher the better?

Electric car industry has become increasingly popular. But as an emerging industry, it develops with multi- thinking and multi- route and has not formed the inherent mode. This confuses consumers.

The battery voltage for example, the initial electric bike voltage is generally 36V, some 24V, or even 12V(Because it was all lead-acid batteries, a lead-acid battery voltage is 12V), then the electric scooter voltage up to 48v, 60v, 72v, 84v, even more than 100V.

While the electric car needs more power, so the battery voltage is generally more than 100V, most 300V, even the highest more than 600V.

A lot of people wonder: is the battery voltage of electric cars higher better or lower better? Does higher voltage mean better performance?

To understand this problem, first of all we need to learn the relationship between voltage, current and power. The formula is simple:

voltage * current = power

For example, if an electric vehicle has a battery voltage of 48V and a working current of 30A (ampere), the output power of the battery will be 48*30=1440W

If you have ever ridden an electric car, you should know that the electric bike of this power is actually very general. If you want to get more power, you can either increase the battery voltage or increase the working current.

Heightening the battery voltage

Suppose we put the 48V battery voltage of electric vehicles, heightening the battery voltage to 72V, 120V.There's significantly higher power.

It seems that the higher the voltage, the better. But the voltage will lead to the two biggest drawbacks: safety and electrical parts design difficulty.

But the alternating current (ac) is more dangerous than with dc voltage. According to the different laws and regulations, generally less than or equal to 36V or 48V dc is considered safe voltage. More than 60V voltage can be harmful to the human body. Products above 48V in Eu electrical regulations require additional electrical safety certification. In principle, batteries higher than 48V should be electrically insulated and waterproofed to comply with regulatory requirements.

Electric power lines are more than 1000V insulation protection and waterproof IP67 rating, and the protection requires a lot of cost and occupies the space of car body layout.

Furthermore, the electronic and electrical design of high voltage circuit is also very difficult. Because of the electronic components are stress levels. To achieve a higher pressure, often means that the electrical parts need higher cost and larger volume. And high pressure inevitably need batteries in series number multiplied, the battery management system is more complex, also impose costs have risen sharply.

BMW C - Evolution modular battery structure

It can be seen that brought by the high pressure is the rise in cost and assembly requirements of the space. So now it is generally electric vehicles such large size, high value products use more high-voltage batteries.

Increase the working current

We now look at increasing the working current, suppose we put the 48V battery voltage of electric vehicles, increase current to 50A, 80A,the power can also increase significantly.

However, the disadvantages of increasing the current are obvious. The circuit itself also has resistance. So when the current passes through the circuit, it will consume electric energy due to the heating of the resistance. The larger the current is, the greater the wasted electric energy will be lost on the transmission line. That's why the national grid uses tens of thousands of volts, hundreds of thousands of volts.

At the same time, high current operation also puts forward higher requirements for electronic components. Once there is a small design is unreasonable or defective, the large current will magnify the problem, causing rapid damage and even causing greater risks such as line combustion.

Therefore, whether it is to increase the battery voltage or increase the operating current to improve the working power of electric vehicles, if not through reasonable design and strict test, there will be a great safety risk.

Many electric cars on the market is easily configured 72 ~ 110V.But because of the cost or space layout, there is great potential safety hazard for no corresponding levels of insulation protection. As a manufacturer, this is irresponsible behavior. As a consumer, you should choose a reliable manufacturer.

In recent years, many automobile and motorcycle enterprises have begun to promote low-voltage solutions. In the automobile industry, Japanese automobile manufacturers represented by Toyota began to use 48V system solution in electric vehicles. In the motorcycle industry, BMW, KTM, American ZERO, Harley, white ghost and so on, all have 48V electric motorcycle products.

The page contains the contents of the machine translation.