1. Overview

This equipment is suitable for dry leak testing of finished lithium battery cores (hereinafter referred to as workpieces) after injection and sealing nail welding of square aluminum shell lithium batteries.

The manually loaded workpieces, which have been filled with helium in previous processes, are placed into the vacuum chamber. The equipment utilizes the vacuum chamber method for helium mass spectrometry leak testing to determine the qualification of the tested workpieces.

The system is designed and manufactured strictly according to the requirements of the customer, employing modular design to fully consider leak detection requirements. Standardized modules and components are used wherever possible to ensure system reliability, maintainability, and compliance with specified technical standards.

2. Main Technical Parameters and Requirements

1. Workpiece Volume: ≤ 2L

2. Maximum Workpiece Dimensions: 136mm X 32mm X 221mm (based on drawings provided by the customer)

3. Detection Accuracy: Approximately 5×10-7 Pa.m3/s

4. Test Pressure in Leak Detector (inside vacuum chamber): ≤ 40 Pa

5. Leakage Rate Control Setting: Set by the customer according to their process requirements on the leak detector or system

6. Internal Chamber Dimensions and Volume of Vacuum Chamber: 250mm (L) × 100mm (W) × 300mm (H), approximately 10L

The dimensions of the vacuum chamber are determined by mutual agreement based on the largest existing workpiece dimensions. Any adjustments in workpiece size or placement by the customer may require supplementary agreements or adjustments in vacuum chamber size, potentially extending the testing time.

7. Number of Vacuum Chambers: 2

8. Number of Workpieces Tested per Chamber: 1

9. Vacuum Chamber Door Opening/Closing Method: Drawer type

3. System Introduction

3.1 Vacuum Chamber Section

The vacuum chamber section includes the vacuum chamber, workpiece positioning device, vacuum pump unit, vacuum measurement device, solenoid valves, pneumatic door opening/closing device, pipelines, and framework.

The vacuum chamber is made of stainless steel or hard aluminum, with polished and cleaned internal surfaces to ensure low background and minimal trapped gases, thereby enhancing pumping speed. The vacuum chamber door adopts a pneumatic switching mechanism for simple and reliable operation, significantly improving leak detection efficiency.

The primary vacuum pump uses Leybold vacuum pumps, known for their stable and reliable performance.

3.2 Leak Detector Section

The leak detector section mainly consists of a helium mass spectrometer leak detector, control valves, and calibration components. The helium mass spectrometer leak detector utilizes the A100 helium mass spectrometer, which is advanced in technology, stable in performance, and easy to install and maintain.

3.3 Electrical Control Section

The electrical control section employs PLC control to integrate the leak detector, vacuum chamber, and inflation/venting parts organically, ensuring a coordinated and stable control system. Various information such as evacuation time, vacuum level in the vacuum chamber, alarm values, and leakage rates can be displayed and set on a color touchscreen. The system can store parameters for different types of workpieces, facilitating production needs.

The electrical control features include:

• All parameters can be displayed and modified on the touchscreen with password protection.

• Automatic transition to alarm screen upon system alarm, with sound prompts and return to initial operation interface after alarm confirmation.

• Manual operation screen mirrors automatic operation functions.

• PLC status monitoring screen provides real-time monitoring and control of system operation.

• Cumulative count of non-conforming chambers after each startup, with manual reset capability.

• Fault diagnosis function.

3.4 Helium Purge System Introduction

The equipment includes a helium purge function to inject high-purity nitrogen into contaminated vacuum chambers and common pipelines before the next leak test, ensuring that elevated helium background levels do not cause false alarms (ambient helium concentrations must not exceed specified limits).

3.5 System Safety Description

The system features extensive safety configurations to ensure operational safety for both the system and operators, including overload protection for vacuum pump units, automatic protections for nitrogen and helium pressure anomalies, safety grating for vacuum chamber doors, and various alarms and protections for malfunction scenarios.

3.6 Equipment Appearance and Other Details

1. Rational layout of components inside the system, with easily detachable and replaceable vulnerable parts for ease of maintenance.

2. Clear labeling of control circuitry endpoints and wiring terminals.

3. Properly marked direction of air pipes and robust material for cable ducts.

4. Standardized and orderly pipeline routing with adherence to national standards, clear textual and directional signage.

5. Main switches for air and power sources installed in easily accessible locations.