Case Studies

Battery Test System for Pack Remanufacturing and Warranty Servicing Process

Posted in Automotive, Battery Pack Test Systems, Energy and Utilities, Green Technology, LabVIEW, Test & Measurement Automation, Test Stand

Summary

DMC utilized the DMC Battery Test Platform to develop a Test Control Panel software application to perform automated testing of a Client's automotive lithium ion battery packs.

This test system allowed the Client to instate an efficient process for evaluating the operating state of battery packs returned under warranty claims, and thereby greatly reduced the cost of servicing these warranty claims.

Battery Module Test System - Test Stand Structure

Test Control Application - DCR and Capacity

Battery Module Tester System State Diagram

Test Control Application - Set Target SOC

Solution

Experienced Client engineers selected the instrumentation/components, designed the hardware platform for the battery module test station, and developed test specifications to define the desired testing procedures.  Although the Client had expert test engineering and software programming resources on staff, the Client chose to engage DMC to handle the software programming portion of the test system development. This allowed the Client to expedite the overall implementation schedule of the test system (in turn allowing the Client to begin realizing cost savings sooner from reduced warranty servicing costs), as well as to allow the Client's engineering resources to focus their valuable time on developing and executing their battery pack remanufacturing process.

DMC programmed a LabVIEW-based Test Control Application to test the Client's automotive battery packs in full accordance with the Client's prescribed testing specifications.; DMC implemented this application rapidly by leveraging existing code modules from the DMC Battery Test Platform and molding these preexisting frameworks to the Client's unique hardware architecture and testing requirements. 

The Test Control Application provides fully automated functional testing of battery pack samples through a "Test Executive" architecture.  This highly configurable architecture allows engineering users to establish a library of defined test procedures by adjusting input settings and grading criteria for pre-defined test processes (based on testing specs).  A flexible test sequence management interface then allows these test procedures to be sequenced together to build a comprehensive functional testing regimen.

The battery testing capabilities provided by this test station include the following:

  • DUT Connection Test: Performs appropriate continuity measurements to ensure proper DUT Connection to test stand
  • Incoming/Outgoing OCV Test:  Performs a check of the open circuit voltage of the battery module
  • Cell Voltage Reporting Test: Acquires and grades individual cell voltage values as reported over the DUT's LIN interface
  • DUT Thermistor Test:  Measures and evaluates thermistors within the battery module
  • Insulation Resistance Test:  Performs DC HiPot insulation resistance measurements from battery module's high voltage bus to low voltage / chassis connections
  • Set SOC Test: Charges or Discharge the battery module as needed to drive the module's State of Charge to a target percentage
  • DC Resistance and Capacity Test:  Subjects the battery module to a discharge current pulse to measure the DC resistance and capacity of the battery module

Learn more about DMC's battery pack and BMS test system services. 

Customer Benefits

Previously, the Client had no manageable process for evaluating battery packs that were returned by the Client's customers during the warranty period to identify what, if any, faults were actually present in the returned packs.

The test stand programmed by DMC allowed the Client to implement an efficient process to identify and isolate root causes of faults or performance issues in these returned battery packs.  This Client obtained a large ROI on the implementation of this test system from a major reduction in the overall cost of servicing warranty claims, and provided their customers with the option of replacing damaged out-of-warranty battery packs with a low cost, high quality remanufactured component.

Instead of being saddled with the high costs of providing customers a new replacement pack with "no questions asked" for warranty claims, the Client was able to manage these claims in an optimal manner for each returned battery pack.  For remanufactured battery packs, the Client was able to perform targeted repairs for common fault cases like damaged power bus bars, directly replace the small subset of packs with prohibitive repair costs, and redeploy returned packs that in fact had no faults and were perfectly operational.

Technologies