In today’s electronics applications, batteries power nearly all of our portable electronic devices. Batteries also serve as emergency power backup systems on large premises. And all-electric vehicles use large cascading battery packs to meet the expected power for the required performance.
In this guest commentary, Bernard Ang from Keysight Technologies shares his insights on specialised battery testing.
Batteries are the key to our portable/mobile electronic gadgets in this digital era.
Battery packs need the required specific power (W/kg) to be able to dispense enough current to achieve the electric vehicle speed performance.
They also need the required specific energy (Wh/kg) to achieve longer runtime or travel range.
Why is it important to monitor battery temperature?
Most rechargeable batteries today are lithium ion and have an operating range between 15 °C and 35 °C at which their full performance and capacity kicks in.
- If the battery and its ambient temperature is below 15 °C, you may experience sluggish electrochemical reactions within the battery and as a result, lower battery performance and reduced charge capacity.
- If the battery or battery pack operates above 35 °C in ambient temperature, battery degradation can accelerate over time. As a result, you may notice shorter battery life, non-uniform aging due to thermal gradients, greater exposure to safety issues, and higher life cycle costs. At extremely hot temperatures, batteries can break down and cause leakage, smoke, fire, and even explosions.
The power map chart below shows the power limits of your lithium-ion battery or battery packs across the temperature range.
Power map chart showing the power limits of a battery or battery pack across temperature range (Source from Kandler Smith, NREL milestone report, 2008).
The range between 15 °C and 35 °C is the optimum operating temperature range for the batteries to achieve full performance.
The temperature range is also the most efficient, reliable, and safe range for battery operation.
When to use a data acquisition (DAQ) system for monitoring battery temperature
A data acquisition (DAQ) system is one of the most versatile instruments to measure the temperature of physical objects or multiple objects.
About the Author: Bernard Ang is a product marketing manager at Keysight Technologies. Bernard has been with Test and Measurement industry for twenty years. He was a product engineer for microwave test accessories, spent a short stint as an Oracle manufacturing data transition manager, and moved on to work in basic instruments as a program manager in the product development group for close to ten years. He is currently a product marketer for general purpose bench instruments.
A DAQ system monitors temperature at multiple points in a product’s battery system.
Typically, you initially test functional design blocks independently, and then you test sub-integrated design blocks during a product design and development stage.
Testing for lab battery packs and systems occurs during an early product design cycle using several common R&D lab instruments.
A DAQ system can be used to monitor temperature at multiple points in a product’s battery system.
Charge the battery system with a DC power supply and use a DC electronic load to discharge the battery system.
Using Keysight’s PathWave BenchVue software application, you can quickly set up and execute tests and get results faster.
The application’s test flow feature allows you to build automated tests and reduces test development time significantly.
A common lab test setup for product battery system test using a DAQ, DC Power Supply, and DC electronic load. If you happen to own a bidirectional DC power supply that can source and sink current, then you can replace the separate DC power supply and DC electronic load with a bidirectional DC power supply.
The test flow feature also enables the simple sequencing of instrument settings and measurements, and combines multiple instruments to help you create your own automated test.
PathWave BenchVue software allows you to:
- Test the battery management system in your devices by varying the charging sources and discharging the electronic load while monitoring the temperature and behavior of your battery system.
- Perform multiple temperature point measurements to evaluate cell-to-cell temperature variations.
- Set alarm triggers to monitor temperature, voltages, or currents if they go above or below acceptable limits.
When to use a specialised battery test system for monitoring battery temperature
Performing quick workarounds on bench test instruments may serve you well for quick troubleshooting and verifying your battery system design.
However, when you need a dedicated and well-supported specialised battery test system, Keysight’s Scienlab SL-1000 series provides reliable and precise testing of battery systems whether they are in the cell, module, or at the pack level.
The Scienlab SL-1000 series battery test system is scalable up to 1000 V, ± 2400 A, and ± 360 kW.
This figure shows the Keysight Scienlab battery test system which is scalable from individual stand-alone solutions, to fully integrated test systems and ready-to-use test laboratories.
The battery test system is suitable for various energy storage applications ranging from automobile transportation, to industrial and other large on-premise use cases.
The Keysight Scienlab SL-1000 series battery test system offers many features that make it a standout in the market.
The system comes with integrated test environments for your device under test (DUT) such as temperature and climate chambers, conditioning for your DUT, and standardised contacting systems and integration to your DUT.
There are also built-in safety and security mechanisms to help you avoid potentially hazardous situations.
Summary
Monitoring battery temperature occurs throughout the battery system’s product life cycle.
References
During the early stages of the product life cycle, engineers can quickly troubleshoot and validate their battery system designs with bench instruments such as a DAQ, in conjunction with a current sourcing and sinking DC power supply.
During the characterization and qualification stages of the product life cycles, the Keysight Scienlab battery test solution becomes invaluable to you to ensure a precise and volume scalable test solution.
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