Let’s learn about Ligao’s BMS control board---structure and process analysis
Latest update time：2021-07-22
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I have some free time in the past two days, so I will hurry up and write another article. I haven’t updated it for a long time. I will gather popularity first and then gradually return to normal.
Today, let’s learn about a certain BMS controller from Ligao. The picture of the product is as shown below. This is a relatively old product, estimated to be six or seven years old. Because I have not come into contact with their products before, this time Take a good look.
You can find some product application information on the back of the product, including customers, corresponding models, and software and hardware version numbers; the model corresponding to this controller is BC52A.
The size of the entire product is approximately 202mm*97mm*35mm. It is a metal black shell, which is coated with insulating paint. The basic information of the product is posted on the surface of the product, including connector pin definitions, etc.; the protection level of the overall shell is expected to be IP3X.
The casing of the product is divided into two parts: the upper and lower casings. Remove the 4 M3*6 flat-head screws on the left and right sides. Remove the upper casing, as shown in the figure below.
You can see that there is a black PCB inside. The biggest advantage of black PCB is to prevent others from copying the board, because the traces look very unclear.
After removing the five M3*8 screws on the PCBA, you can remove the lower case, as shown in the figure below: There are five corresponding mounting posts on the lower case, and an insulating pad is pasted inside the lower case.
Let's take a look at the PCBA of this main control board BCU. From the information on the Internet, we know that this BCU does not have high-voltage modules, such as insulation detection, high-voltage sampling, etc. More decoupled. (The picture below comes from the Internet)
The TOP surface of the controller is shown in the picture below. The size of the entire PCBA is 170mm*96mm*23mm, which should be a 4-layer board. All devices are coated with conformal coating. This conforming coating is relatively soft and can be easily scraped off. ; And there is a little glue treatment on the high components on the TOP surface, such as electrolytic capacitors, relays, etc.
The BOTTOM surface is as follows. You can see that there are very few test points on the entire product, and there are basically no ICT test points. There are a total of 3 connectors on the PCBA, all of which are in-line packaging. The left and right connectors have locks on the B side. The screws are from TYCO; the middle connector is from MOLEX; there are quite a lot of plug-in components on this board.
The function distribution of the three connectors is as follows (pictures come from the Internet). By definition, they are all low-voltage signals.
The C-P2 connector is an external USB interface, which is equivalent to a U disk function and can copy the data on the TF card; because this product is relatively early, the current BMS generally does not have this interface, and the data is passed through Get it by uploading it to the cloud.
The C-P1 connector is mainly for small signal relay output and Hall sensor power supply and input, as shown in the figure below: There are a total of six relay control outputs. These small signal relays should be used to drive external high-voltage relays.
The C-P3 connector is mainly used for external communication signal output and power supply input of the board; its external communication includes CAN and 485, and it seems that there is isolated communication.
Summarize:
This time I mainly introduce its structure and process characteristics. If I have the opportunity, I will learn about the internal circuit structure later. It has been raining heavily in many places these days, especially in Zhengzhou. I wish all the friends there are well; all the above are for reference only.
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