Example of a battery test stand
The development of new batteries and battery management systems requires extensive testing and validation - especially with regard to the specified application. This includes investigations of charging and discharging cycles at different temperatures. These tests are carried out in specially protected climatic chambers and require extensive instrumentation.
Requirements for measurement systems:
For a detailed analysis of the battery and its cells, temperatures and cell voltages have to be measured in many places. Over 100 measurement points are not a rarity here. Due to the high common-mode level of the battery of up to 800 V, a highly isolated measurement technique is required which allows for safe testing.
Measurement technology used:
On the battery test stand, 20 imc CANSAS-HCI8 CAN measurement modules were used. Each module offers 8 highly-isolated inputs for measuring cell voltages or temperatures (thermocouples and PT100) at up to 800 V voltage levels. In sum, up to 80 cell voltages and 80 temperatures can be measured simultaneously.
Highly isolated and safe:
The high-isolation strength of 800 V CAT I and 300 V CAT II ensures safe measurements (EN 61010).
Automation system integration:
The imc measurement modules support the CANopen protocol for particularly worry-free integration into the automation environment.
As an additional security, an imc BUSDAQ-X data logger was used which also monitored and stored all measurement data from the imc CANSAS modules. The data logger took over the following functions:
- Sensor-break detection for thermocouples
- Monitoring of measurement values according to min and max values (comparative operations)
- Monitoring of implausible measurement value change by monitoring rise/fall (differentiation: result for rise/fall speed too high)
- Monitoring if measurement values no longer change (differentiation: long-term average value and short-term mean value equal to zero)
- Power failure
- Termination of the test
- Backup in ring buffer
- Deactivation of test stand components possible