Chroma EV/PHEV Battery Packs

Chroma Battery Test Solutions

DC Impedance Measurement For Battery Cell

The battery pack for electric vehicles requires the battery cells be paralleled for large current use. An important parameter is the impedance consistency of the battery cell since battery life may be affected if the impedance is not consistent. The DC impedance test solution offered by Chroma sets the discharge current change (ΔI) and measures the voltage change (ΔV), and then calculates the battery’s internal resistance using ΔV/ΔI as shown in the figure below.

Chroma’s 63600 Series Electronic Loads supply a 6V/16V/80V voltage range with 0.025% + 0.01%F.S. accuracy to measure the small changes of a battery cell. Each module is able to perform 80A low voltage loading and up to 400A loading when 5 modules are paralleled. The loads feature a high speed data digitizing function that captures the voltage and current every 2us with a maximum 4096 measurements for digital waveform sampling.

Users can conduct the test using our Battery DCR Measurement Software with Chroma 63600 Series Electronic Loads. With the software users can select DC impedance measurements, edit the discharge procedure to test the DC impedance of a battery cell automatically when under different power, and generate a report of the outcome.

Connection Diagram

Test Sequences Editing of Battery DCR Measurement Software

Voltage & Current Waveform Analysis of Battery DCR Measurement Software

Test Report

MODEL DESCRIPTION
63600-1 63600 Mainframe for Single Modules
63600-2 63600 Mainframe for up to 2 Modules
63600-5 63600 Mainframe for up to 5 Modules
63610-80-20 DC Load Module, 100W x 2 /80V/ 20A
63630-80-60 DC Load Module, 300W/ 80V/ 60A
63640-80-80 DC Load Module, 400W/ 80V/ 80A

Battery Module & Pack Charge/Discharge Test

Software

Chroma provides battery charge/discharge test software that integrates the DC Source and Electronic Load to perform battery pack simulation testing. This system facilitates the R&D/QA to test the battery for capacity, discharge performance to get the C-V curve under different discharge rates, and endurance in cycles. Functions of the battery charge/discharge test software include editing test sequences, loops, and stop conditions. All tested voltage/current/power data is recorded in a file for immediate analysis.

Setting & Monitor Software

Test Report

Dynamic Discharge Simulation Test for Battery Pack

The discharge waveform is irregular for EV/HEV battery applications. Although various batteries capacities are labeled the same, the discharge rate varies with materials used that cause driving distances to be different. Thus, it is necessary to use the actual current waveform to perform battery discharge testing for performance evaluation which can serve as the basis for battery materials selection or BMS design.

The advanced dynamic current waveform discharge simulation software provided by Chroma is able to read actual recorded battery discharge waveform data in Excel format and use a digital/analog converter to control the Electronic Load to discharge the same current. This allows both automotive and battery pack manufacturers to simulate the application of irregular battery discharge and conduct repetitive tests in the lab rather than perform costly real road tests every time endurance evaluation is required or analysis is needed to test the material characteristics of a battery cell.

Dynamic Discharge Simulation Software

Record The Current Waveform During Road Test

Dynamic Current Waveform Discharge Test