TIDUEY0 November   2020

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  5.   5
  6. 1System Description
    1. 1.1 Li-ion Battery Formation
    2. 1.2 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 High-Resolution PWM Generation
      2. 2.2.2 Feedback Controller
      3. 2.2.3 Multiphase Configuration
      4. 2.2.4 Current and Voltage Feedback
      5. 2.2.5 Delta-Sigma ADC Clock Frequency Tuning
      6. 2.2.6 Minimize Crosstalk Error With a Differential ADC
      7. 2.2.7 Overcurrent Protection
    3. 2.3 Highlighted Products
      1. 2.3.1 TMS320F280049
      2. 2.3.2 ADS131M08
      3. 2.3.3 INA821
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Hardware Requirements
    2. 3.2 Software
    3. 3.3 Test Setup
    4. 3.4 Test Results
      1. 3.4.1 Constant Control Accuracy ADS131M08 Feedback
      2. 3.4.2 Constant Control Accuracy 12-bit ADC Feedback
      3. 3.4.3 Constant-Voltage Control Accuracy
      4. 3.4.4 CC, CV Transformation
      5. 3.4.5 Constant-Current Transient Response
      6. 3.4.6 Charge to Discharge Mode Transition
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 BOM
    2. 4.2 Tools and Software
    3. 4.3 Support Resources
    4. 4.4 Trademarks
  10. 5About the Author

1.1 Li-ion Battery Formation

Figure 1-1 shows a simplified Li-Ion battery manufacturing process. Battery testing comes at final stages of the production, in which formation is the most critical process. After the cell assembly process, each Li-ion battery goes through gradual charging, during which it forms a solid electrolyte interphase (SEI) layer that can consume significant portions of total battery capacity. Therefore, the test equipment must be able to precisely control the thickness of the SEI layer, which can bring down the capacity loss during formation to below 5%.

Tests such as self-discharge measurement and life span estimation are performed to remove defective cells during production. The battery test equipment must possess accurate voltage and current control, often better than ±0.05%, over the specified temperature range.

GUID-20201020-CA0I-JCC3-ZN5G-37NSBRRGFRD2-low.gifFigure 1-1 Simplified Li-Ion Battery Manufacturing Process.