Let’s take a look at the differences between energy storage BMS and electric vehicle BMS.

It’s quite interesting to be exposed to energy storage projects recently. Energy storage is not a new thing. I was doing energy storage when I just graduated, but I didn’t understand it at the time. Energy storage has become very popular in the past two years. For me, Talking is also an opportunity to reorganize knowledge in this area.

What are the differences between BMS for energy storage and BMS for electric vehicles? I asked about artificial intelligence here and the answer is as follows. I feel it’s not even interesting.

Today I want to make a comparison between energy storage BMS and electric vehicle BMS from the perspective of standard definitions, that is, the following two standards correspond to the application scenarios of the two industries. The purpose of the comparison is to see what the energy storage BMS has to offer. different.

"GB/T 34131-2023 Battery Management System for Electric Energy Storage"

"GB/T 38661-2020 Technical Conditions for Battery Management Systems for Electric Vehicles"

Use environment requirements

Let’s first look at the usage environment requirements. The usage environment requirements for BMS for electric vehicles are as follows, specifically including temperature, humidity, and power supply requirements. The power supply requirements are clearly divided into two intervals. Passenger cars are basically in the 9V~16V range.

Let’s look at the requirements for energy storage BMS as shown below. It includes requirements for temperature, humidity, altitude, and salt spray. Electric vehicles also have application altitude requirements for BMS, but they are generally placed in the requirements of the OEM; as for salt spray , electric vehicle BMS generally does not require it; for energy storage BMS, the standard does not define power supply requirements. It is actually understood that there are two types of power supply, 12V and 24V, but there is no standard to further define the use occasions of these two power supplies; some The supplier has made the energy storage BMS compatible with both 12V and 24V power supplies. In fact, there may be some restrictions on device selection.

Basic functional requirements

The basic functions of electric vehicle BMS are as follows, covering collection, calculation, alarm, charging, etc.

The basic functions of energy storage BMS are as follows. Through comparison, it is found that the functional requirements of the two are actually similar. Of course, energy storage BMS does not have special charging management requirements. As for data collection objects (such as cell voltage, temperature, total voltage, current, insulation resistance, etc.) are the same; the relay adhesion detection function not mentioned in the standard is also available.

Detection performance requirements

The detection accuracy requirements of the two BMS defined in the standard are as follows. When comparing these two standards, the accuracy requirements are different from each other; and the electric vehicle BMS has requirements for SOC detection accuracy, but the energy storage BMS has requirements for SOE detection accuracy. , I still can’t answer the reason.

Test performance requirements

Both divide test projects according to electrical, mechanical, environmental, EMC and insulation performance aspects, and compare several key projects.

1. Insulation performance

Specifically including insulation testing and withstand voltage testing, the specific requirements for electric vehicle BMS are as follows:

The specific requirements of the energy storage BMS are as follows: In the insulation resistance test, the energy storage BMS does not require the insulation resistance size during operation. This size actually limits the value of the bridge arm resistance in the insulation detection circuit; the withstand voltage test is called dielectric strength here. Test, because the platform voltage of energy storage may be higher, so a higher test voltage is defined here.

2. Electrical test

The electrical test items of the electric vehicle BMS are very clear, and there are very clear reference standards, such as ISO 16750, which can achieve dozens of tests in total; while the electrical test items of the energy storage BMS are rarely written, as shown in the figure below, only roughly I wrote several projects, including DC power supply range, anti-reverse connection, overvoltage, communication short circuit, etc.; I think the possible reasons are that the automobile has been developed for a long time and is relatively mature, and each test has a clear corresponding scenario; the second is that the two The application environments of users are different, and some test items may not be applicable, but I personally think that the number of electrical test items for energy storage will gradually increase.

3. Environment and EMC testing

There are more test items in these two test standards, and there are differences in comparison. Especially in the EMC test of energy storage BMS, there are some items that have not been tested on electric vehicle BMS, as shown below, here You need to interpret the standards yourself.

Finally, the energy storage BMS defines the lifespan and MTBF; the BMS of electric vehicles also has requirements, which are generally released by the OEM, and the BMS itself must match the requirements of the entire vehicle.

Summarize:

After writing for so long, I finally wrote about energy storage. The voltage of the energy storage system reaches a maximum of 1500V, and the maximum voltage of electric vehicles currently only reaches 1000V, so I want to summarize the safety design again later; all the above are only for refer to.