The liquid cooling plate is a cooling component of the power battery pack of new energy vehicles, which is often used at the bottom or side of the battery pack. The liquid circulates through the internal flow channel of the cooling plate, which can take away the excessive heat during the work of the battery pack, so as to achieve safe cooling and avoid the aging of the battery caused by excessive temperature.

The liquid cooling plate is usually composed of some thin aluminum alloy heat sink through nesting or welding, etc., and some guiding internal channels are set up inside the plate to guide the fluid cooling medium to take away the heat, but the liquid cooling plate requires strict air tightness testing to ensure the heat dissipation effect and durability.

Liquid cooling plate air tightness testing method

1. Pressure method

Pressure method is also called pressure reduction method and gas test method. There are usually direct pressure air tightness detection, differential pressure air tightness detection and other detection methods, according to different product needs to choose the detection method, the power battery liquid cooling plate air tightness test is usually carried out by direct pressure detection.

This method needs to inject gas with specific pressure into the liquid cooling plate parts according to the detection requirements, observe the size of the internal pressure change of the workpiece through the pressure holding, and then judge whether there is leakage of the liquid cooling plate workpiece. Observe the pressure holding condition, if the pressure holding capacity exceeds the standard, the air tightness performance of the liquid cooling plate is better.

2. Soaking method

Soaking method is also known as water inspection, the liquid cooling plate to be tested is immersed in water, and then observe whether there are bubbles, if there are bubbles, indicating that the liquid cooling plate has loopholes, does not meet the detection standards.

3. Hydrogen leak detection method

Before the test, prepare a water container, pressurize the water in the container, so that the difference between the water pressure before and after the container is between 5 and 10MPa, and then place the outlet of the liquid cooling plate under the water surface of the pressurized container, such as the leakage of the liquid cooling plate, then the hydrogen at the outlet will be absorbed by the water, and the hydrogen in the water will be tested by the detection instrument. We can locate the leakage point of the liquid cooling plate.

4. Thermal cycling method

This method is to first put the liquid cooling plate in a low temperature environment, and then quickly heated to a high temperature environment, to observe whether the liquid cooling plate has deformation or loopholes, if there is, it indicates that the liquid cooling plate air tightness is not good.

Test requirements of liquid cooling plates

Test pressure: 200kpa-250kpa Standard: < 50pa, IP67

 Air tightness test introduction

The air tightness test is a test method to verify the air tightness of the container, also known as the tightness test or waterproof test. It is a compact test using gas as the pressurizing medium in order to prevent the leakage of the pressure vessel. The air tightness test must be qualified in the hydraulic test before it can be carried out, and the test method will be different according to the different device. In the process of selection and preparation for detection, it is also necessary to master some principles, such as the liquid in the device to form a closed environment, so that the temperature can be changed, and the strength of the pressure can also be changed, and the air tightness can be effectively judged through this change.