The trend towards climate protection through "sustainable solutions" that reduce CO2 emissions is driving technologies such as high capacity/high energy batteries or H2-based fuel cells as the main sources of mobile energy. Moving away from internal combustion engines also requires a new mindset in testing and measurement, including new safety concepts, new test environments, new types of sensors and measurement technologies, and customised data analysis.
New drive technologies - new testing requirements
In the search for sustainable, eco-friendly mobility, HBK soon faced challenges in the development and testing of mobile energy storage for vehicles. As a market leader in test and measurement, electrical performance, sound and vibration testing, and environmental testing, HBK gained early insights into the many requirements and needs of industries such as automotive and commercial vehicle development when it comes to validating innovative energy storage and overall NEV concepts.
Batteries with voltages of up to 1000 V in modern vehicles require a huge range of tests, augmented by special precautions when handling dangerous electrical voltages and lithium as essential elements of the electrochemical process. Within the test range, HBK covers most of the measured quantities:
- Electrical voltage, current and power to analyze the efficiency and performance of the entire powertrain.
- Safety short circuit tests and optimized charging tests.
- Strength, thrust, pressure and weight for mechanical resistance analysis.
- Temperature, flow and pressure for heat resistance analysis.
Combustion engine testing includes up to 300 temperature measurement points and highly dynamic torque, speed and pressure measurements. With the integration of batteries and fuel cells, the number of measurement channels is moving towards the energy storage as the largest component of the modern powertrain.
Why measurement and data analysis?
In today's electrified powertrain solutions, all aspects from single cell batteries to battery packs are covered by virtual (simulation) and physical testing with the following typical scope:
- Long-term battery reliability testing with a focus on discharge/charge cycles (slow, fast), self-discharge including voltage and temperature measurements of individual cells and overall performance analysis.
- Dynamic testing with a focus on performance, efficiency and feedback during recovery.
- Environmental testing in which application-specific mechanical load profiles are performed on LDS vibration systems in combination with cyclical temperature increases and decreases in a climate chamber.
- Misuse and impact testing (overload, short circuit, overheating, mechanical stress, fault).
- Structural integrity tests, starting with mobile vehicle tests for road load data acquisition (RLDA), summer/hot, winter/cold tests with transient phenomena.
Battery design testing
Batteries are one of the largest and heaviest components in modern electric vehicles. The overall lightweight design and flexible battery packaging must be balanced. Optimal weight, structural durability and overall life cycle estimation are key parameters that need to be verified before production begins. HBK is one of the leading suppliers of complete measurement chains not only for measurement and physical structural resistance testing, but also for virtual structural resistance testing and lifetime estimation.
Battery pyro-fuse short circuit test
Qualification of high power traction battery circuit breakers and pyrofuse requires the ability to measure currents in the range of several kiloamperes with extremely high sampling rates to capture peak current. It also requires the ability to measure currents on the order of a few amperes accurately and with high dynamics. And given the high voltages, high currents and extremely fast dynamic events, it places high demands on the DAQ system used with respect to EMI immunity, surge protection and isolation. One way to perform short-circuit tests is to use non-linear current sensors and Genesis high-speed data loggers.
Cell case testing: mechanical testing of batteries
Force sensors can help you understand how fast the battery capacity is decreasing, as they can be used to evaluate the stress on the battery cells during charge/discharge cycles.
In the so-called cell case test, a force sensor measures the mechanical stress that occurs inside the battery under different charging conditions. This stress is important for the performance of the battery, as it can lead to a loss of capacity or, in extreme situations, to complete battery failure.
Get to know the most important features of force transducers for mechanical testing of batteries.
Electrical qualification and verification under dynamic load conditions
Qualification and verification of these systems is essential before the traction battery can be placed on the market. A suitable test bench must cover a high voltage and current range as well as high dynamics and should be able to perform the necessary tests in the most realistic and application-oriented way. To this end, the measurement techniques must be highly accurate and dynamic.
How this can be achieved and how HBK equipment can help, you can find out here.
Thermal management of the battery
Batteries are the foundation and largest single component of a modern battery electric vehicle (BEV) or new electric vehicle (NEV). It is about finding and verifying the optimal key parameters of the whole assembly.
The limited performance of lithium-ion batteries at extreme temperatures drives the complexity of thermal management systems with supporting auxiliary units and air cooling paths. Excessively high temperatures can lead to self-destruction and even fire (thermal runaway). Extensive testing, and in particular thermal validation, are therefore essential in the overall test setup.
Operational safety is one of the most important requirements. Lifetime expectations range from a minimum of 10 years, 450,000 kilometres or a target charging time of five minutes for super chargers. Battery reuse and second life are also important issues.
Thermal management of battery life is crucial for parameters such as speed performance, safety, cost and many others. Thermal analysis therefore requires numerous temperature measurement sites with the highest demands: small measurement sites, maximum safety with double insulated sensing lines, electrically isolated channels...
Thermal analysis of high voltage batteries
Computer thermal simulation using CFD (Computational Fluid Dynamics) models is an important step towards optimal system design. However, it is still necessary to perform physical testing, as simulation cannot cover all architectures, integration aspects or parameters.
During testing in climate chambers, we gain important information about the performance of the batteries. By routinely testing the environment and performance, we can investigate the effect of extreme temperatures. We can find out which cooling systems are best for achieving the desired results. We can perform testing at different levels of integration, from testing individual components to the entire powertrain. In this way, we can optimize the entire system and temperature control before mass production begins.
Long-time expert in thermal testing
HBK has been developing and offering the necessary components for measurement chains for thermal validation for years. These solutions cover electrical, optical or combined - hybrid - measuring chains.
Even internal combustion engines have to deal with the fact that power generates heat. With the electrification of mobility and the upcoming need to develop thermal testing methods here too, HBK has looked at existing procedures and refined them from a new perspective. All the experience and knowledge has thus been processed and adapted to become a specialist also for thermal testing of eMobility and, within this, for battery testing.
HBK's thermal energy storage testing system measures parameters including voltage, current, temperature, humidity, cooling flow, pressure and battery call control system. Power calculations, efficiency, hot spot monitoring, visualization and analysis are performed. Automation deals with test control and safety.
HBK's data acquisition and analysis solution provides thermocouple measurements for the outer part of the electric powertrain and for in-depth battery investigations, including cell voltage, total voltage and current measurements. Universal inputs cover universal flow, pressure, humidity and other required parameters.
HBK is a cost-effective provider of comprehensive solutions for thermal, mechanical and electrical analysis of test samples.
HBK battery testing solution:
Take advantage of the HBK solution and ensure maximum flexibility and investment protection:
- Safety first - HBK meets the EN61010 standard for electrical safety
- Freely scalable and flexible multiphysics DAQ systems for many different testing areas: electrical, thermal, mechanical, ...
- Full channel isolation up to 1500 V DC allows measurements at high potential
- Input ranges up to +/- 1500 V, with CAT III overvoltage class.
- Signal quality resistant to electromagnetic noise
- Optional isolated digitizers for higher isolation and noise immunity
- Powerful open software concept from ready-to-use to real-time integration
- PC-based data analysis and collection in parallel with real-time integration into test benches
- Capture data at the bench, in the lab, and on mobile devices in a single solution that scales to your needs