Category: Electronic Load

The worldwide battery market is undergoing enormous growth, due in large part to recent advances in electronic technology. The automakers have been accelerating Electric Vehicle (EV) development and they are introducing the new EV models in the market. In response to these situation, Company I received a request from its customer for prompt action on developing smaller and lighter batteries with more power.

The Problem

Difficult to meet customer’s request promptly

Leading battery cell manufacturers have built new factories utilizing the latest production techniques, including greater automation and faster throughput. Production volumes alone cannot solve the battery problem. There must be improvements in the battery’s density, materials, weight, and safety for EVs.

The Company I did not have the right test equipment to conduct the Capacity measurement, Over-discharge test, and I/V performance test efficiently for high voltage batteries. When the company submitted a newly developed prototype to the business partner, it failed in their evaluation because of the insufficient performance. To conduct the required tests on batteries, designed test circuits were used. The company needed to adjust the circuits so that any type of battery can be tested with the circuits. Or sometimes the engineers had to design new circuits more than once, when the test conditions were changed. Having not enough skilled engineers, the company could not conduct the tests efficiently, making it difficult to meet the request. The company wanted to establish a new test environment to improve efficiency of their work, but realized that there was no such space to install the system. Mr. A at the Design Development Dept. was seriously concerned about the present situation that the company I had been facing and tried to find the solution in vain.

Key Aspects of the Problem

  • Company I wanted to conduct accurate test on high voltage battery efficiently
  • Having not enough space to install new large instruments

Around the world, efforts are being made to harness the power of hydrogen, the most abundant element in the universe. Using hydrogen results in zero CO2 emissions. Fuel cell vehicles are ideal eco-cars. Fuel Cell Vehicle (FCV) are an expected market trend.

The Problem

Intricate, time-consuming high cost inspection on Fuel Cell weighs heavily upon the company.

The company O manufacturing various automotive components had technical issues in inspection process on Fuel Cell. “Complexed inspection process on Fuel Cell extended inspection time, and it tightened the company’s production schedule”, said Mr. B at the Quality Inspection Dept.

It is essential to conduct impedance measurement of a Fuel Cell on load. Impedance measurement on a battery or Fuel Cell with load is very important in order to examine the influence on its performance. Fuel Cell measurement system that the company owned consists of electronic load and digital multiple multi-meters. It was a complication work by using the system.

Each inspection procedure has each test equipment setup and test method. It requires the test equipment cost and man-hours, since the test methods changes upon the inspection. The test condition varies when measuring discharge characteristics and impedance separately. Due to this, Mr. B could not conduct reproducible test.

These circumstances urged engineers at the company to find the solution for the better test method in order to get test result with ease in a short time. In response to this demand, Mr. B collected information to solve the issues.

Key Aspects of the Problem

  • Multiple test equipment to conduct inspection for Fuel Cell leads to complexity, excessive man-hour and cost increase.
  • Measuring discharge characteristics and impedance separately made test conditions change, this caused low reproducible test.

With the increasing popularity of electric vehicles, the automobile industry is rapidly transitioning to an electronic one. As demand increases for the components that support vehicle systems, including motors and batteries, more manufacturers from other industries have started to produce components for automotive use, causing competition between component suppliers to intensify.

The Problem

Doubling of system voltage meant parts could no longer be tested.

The company that is the subject of this case study manufactures electronic components for electric vehicles. While most electric vehicle systems still operate at around 400 volts, an increasing number of car manufacturers are now releasing 800 volt vehicles, and this had presented the company with a range of issues. The company’s chief quality assurance engineer explains:

“With the shift to higher voltages, the electronic loads we had been using to perform properties testing no longer offered sufficient capacity. Our electronic loads could be used at a maximum of 650 volts, so some components used in 800-volt vehicles could not be tested.”

Efficiency a matter of urgency.

For their part, the company’s engineers were unhappy about the increasingly fiddly testing process.

“We had more parts to test, all rated at different voltages and currents. Whenever we tested a component with a different voltage rating, for example, we had to reconfigure and reconnect the load devices, thereby making the test preparations more time consuming”, reflects the head of QA.

At the time, the company was in the process of moving its focus to electric vehicles, and the QA head’s bosses had told him to reduce testing time and otherwise make the testing operation more efficient.

“The requirement to reduce the size of the testing area was also an issue. While we tried rearranging the existing equipment in various ways, this did not work. We were therefore looking for a new electronic load that would provide an elegant solution to our problems”, he says.

Key Aspects of the Problem

  • The voltage rating of the existing electronic loads made them insufficient for some tests.
  • More components to test meant that the process of preparing for testing had become more complex.
  • The new electronic loads would need to deliver space savings.

Smart devices and devices that utilize information and communications technology are becoming rapidly more sophisticated. The control circuits contained in the field programmable gate arrays (FPGA,DSP,ASIC etc.), digital signal processors, and application-specific integrated circuits, which are central to the operation of these devices operate at increasingly lower voltages and higher currents, have created an increased demand for topologies capable of enduring drastic load variations in the form of point of load (POL) converters.

The Problem

The manufacturer’s electronic load could not handle low-voltage, high current applications or drastic load variations.

The manufacturer produces semiconductor devices and power supplies. When developing a new POL converter, they found that issues with their existing electronic loads were slowing down the development process. A team leader in the design division explains:

“The specifications of our existing electronic loads did not enable us to perform the low-voltage, high current testing required. The loads had a minimum operating voltage of 1.5 V, so had to be combined with extra power supplies or the like to enable low-voltage testing. This made the process of configuring and connecting the loads complex and time-consuming, and also made us nervous about the accuracy of the test results. The loads had a maximum slew rate of 30A/μs, which was insufficient for performing intense load variation tests, and we were therefore, unable to properly evaluate the devices under test.”

He continues:
“In order to simulate real-world applications, we also wanted to run multiple POL converters at once. However, synchronizing the electronic loads was difficult and time-consuming. Our engineers were unhappy about the complex and inefficient nature of the task.”

Deciding that upgrading the electronic loads was a matter of urgency in order to make testing more accurate and more efficient, the team leader began to do some research.

“With digital, large-scale integrated circuits (LSI), a consistent power supply is paramount. We were looking for a high-spec programmable load that could handle low-voltage, high-current applications.”

Key Aspects of the Problem

  • The manufacturer needed an electronic load that could handle low-voltage, high-current applications and drastic fluctuations.
  • The manufacturer also wanted an efficient way of operating multiple POL converters simultaneously.

The client was ramping up development of solid polymer fuel cells, which it made in small lots but to a wide range of specifications to cater to the needs of its customers. However, an inefficient manufacturing processes was causing issues.

The Problem

Misgivings about Electronic Loads.

The issue related to the important task of measuring the power and voltage profile and performance of fuel cells under load. An engineer in the fuel cell development team recalls:

“We would connect together several variable resistors to achieve the desired resistance, but tweaking those resistors to elicit the target load was quite a chore. The job also required a degree of knowledge and experience to be performed properly, and the resulting load banks offered poor accuracy and quality considering the time spent building them.”

The engineer and his team considered getting rid of the bottleneck in the process by switching to electronic loads. However, not many engineers were familiar with these devices, and concerns were raised that their complexity would make it difficult to master their use, and that training would be time-consuming.

“I was surprised when another division asked me to choose a model that could emulate high-capacity fuel cells”, says the engineer.

“Meanwhile, the quality control team also heard that we were introducing electronic loads, and asked me to choose a model that could measure impedance.”

Faced with a barrage of requests from other divisions in addition to his own team’s misgivings, the engineer did not know where to start.

Key Aspects of the Problem

  • Building a load bank to specification was time consuming, yet home-built load banks offered low accuracy and quality.
  • While the engineer considered switching to electronic load devices to remedy the situation, he was reluctant to take the plunge because of concerns about his team’s unfamiliarity with these devices.
  • He was also inundated with requests from other divisions.

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