Vacuum loading on battery pack
现代锂电池组中的空气夹杂或气泡是一个严重而危险的问题。 isi-sys SE2传感器能够在一秒钟内检测出微小和较大的缺陷，例如气泡，气穴，裂纹等。 缺陷可能远低于表面或接近表面。 电池组的示例（来自慕尼黑大学机械与工业管理学院的测试样品）和测量结果如下所示。
Air inclusion or air pockets in modern Li-battery packs is a serious and dangerous problem. The isi-sys SE2 sensor is able to detect tiny and large defects such as air bubbles, air pockets, cracks and other within a second. The defects can be far below or near to the surface. An example of a battery pack (test sample from University of Munich, IWB) and the measurement result is shown below.
试验设置 Test setup:
该测试是SE2传感器结合玻璃真空室通过简单的手动操作完成。 对于现场的无损检测，通过手动形式操作是个经济有效的解决方案。 但对于生产中的自动化系列测试，则需要不同的设置方式。
The test has been done by SE2 sensor in combination with a glass vacuum chamber for a simple manual test. This is an economic solution for spot NDT by manual service. For automated series test in production different setups are required.
测试流程 Test pocedure:
The battery packs are tested by small pressure differences of some mbar, which can be applied in seconds or below in small chambers. The sensor is monitoring the surface of the battery pack while the pressure is changed, measuring the differential deformation of the surface. Due to the expansion of the air bubbles and air pockets, the air inclusions can be located such as shown in the following images.
The first image shows the live view of the battery pack from the sensor. The second shows the recontructed phase, which is corresponding to the local deformation gradient.
Generally the required pressure difference depends on the defect depth, defect size an the mechanical stiffness of the tested structure, but in general the load is small due to the high sensitivity of the sensor detecting differential deformations of the surface.