I. Industry background

　　Under the dual-carbon background, the National Development and Reform Commission (NDRC) and the National Energy Administration (NEA) jointly issued the "Medium- and Long-Term Plan for the Development of the Hydrogen Energy Industry (2021-2035)", pointing out that the focus will be on promoting the development of hydrogen energy and fuel cell automobile industry in a low-carbon manner. According to SPIR data, China's hydrogen fuel cell shipments will be 690MW in 2023, and shipments are expected to reach 6,400MW by 2028, with a compound annual growth rate of 40%.

　　China Hydrogen Fuel Cell Shipments and Growth Rate, 2020-2028

　　II. Application requirements

　　Fuel cell technology has the advantages of environmental protection, high energy efficiency and long range, and is mostly used in cargo and large buses, which requires high safety and reliability. Therefore, China has launched a number of regulations and standards to regulate its safety, cycle life and test efficiency, etc., to provide support for the healthy development of the industry.

　　Relevant criteria:

　　III.Testing Difficulties and Solutions

　　1、 Test Difficulties (Fuel Cell EIS Test Principle Model)

　　Fuel cell internal resistance includes DC internal resistance DCIR, AC internal resistance ACIR and electrochemical impedance spectroscopy EIS, which is one of the key indexes to measure the performance of fuel cells. The EIS test includes DCIR and ACIR tests, and the three impedance relationships are shown in the figure below:

　　The industry typically simplifies the fuel cell test equivalent model as follows:

　　From the above figure, the circuit principle is simplified as follows: DCIR=RΩ+Rct+Rw, ACIR=RΩ, EIS is the complex impedance with wide frequency, EIS needs to be measured in the complex domain, the loop is band-loaded with sinusoidal waveforms, the frequency range is 0.01Hz-20kHz, the peak value of tens of amperes to hundreds of amperes, and the value of EIS is obtained by plotting the cole-cole curve.

　　Complex testing process increases the difficulty of testing, and a perfect fuel cell testing program is especially important.

　　2. Solutions

　　The EIS test of fuel cell requires various measurement equipments such as waveform generator, electronic load, electrochemical workstation and so on. According to the actual fuel cell testing requirements, the waveform generator generates small amplitude sinusoidal potential signals, combined with the external waveform pull-load function of the electronic load, the actual sinusoidal pull-load waveforms of the control loop, and the electrochemical workstation carries out the centralized control and analysis, and ultimately obtains the EIS measurement values. This test program, there are higher equipment costs, low test efficiency, poor reliability, test quality in general, etc. At present, Ainuo Instrument high-power DC electronic load AN23600E series targeted introduction of the SWD mode function, an effective solution to the industry's difficulties, the specific comparative analysis of the following chart:

　　IV. Products

　　Ainuo Instrument has been deeply engaged in the testing industry for many years. Aiming at the difficulties in the production testing process of fuel cells, Ainuo Instrument has launched the special high-power DC electronic load AN23600E series. The load is characterized by fast testing speed, high precision and strong load adaptability, which can greatly improve the testing efficiency of fuel cells.

　　Ø Product Characteristics:

　　(1) Precision measurement technology, voltage 0.015% + 0.015% F.S., current 0.04% + 0.04% F.S. and power 0.1% + 0.1% F.S.;

　　(2) Built-in dynamic load pull mode with dynamic frequency up to 25kHz and Vpk+/- test function;

　　(3) Built-in FLEX mode allows simulation of capacitive loads, inductive loads, and compound impedance loads;

　　(4) Built-in fixed current, fixed voltage, fixed resistance, fixed power, short-circuit simulation, over-current protection test, serialization test and many other functions;

　　(5) Wide range, the same capacity, provides close to two times the current range of conventional high-power loads;

　　(6) Excellent dynamic characteristics, up to 96A/us flow rate increase capability;

　　(7) Complete protection function, support over-current over-voltage over-temperature reverse connection protection and so on;

　　(8) Built-in temperature acquisition chip and speed-regulated fan control;

　　(9) Built-in battery mode, suitable for discharge test for power integration and timing;

　　(10) LED test function, fast simulation of LED volt-ampere characteristic curve;

　　(11) High power density, 6kW height 4U, 24kW height 13U; small size, light weight, easy to operate;

　　(12) Rich interface, standard RS232, LAN, GPIB, CAN, USB, RS485 and other six interfaces.

　　Ainuo electronic load SWD measured waveforms

　　1.Condition 1 test condition

　　a. Load setting: frequency: 1Hz, I_DC: 30A, I_AC: 30A

　　b. Power supply setting: voltage: 15V, current limit: 50A

　　2.Condition 2 test condition

　　a. Load setting: frequency: 1kHz, I_DC: 30A, I_AC: 30A

　　b. Power supply setting: voltage: 15V, current limit: 50A

　　3.Condition 3 test condition

　　a. Load setting: frequency: 20kHz, I_DC: 30A, I_AC: 30A

　　b. Power supply setting: voltage: 15V, current limit: 50A

　　V. Conclusion

　　Ainuo High Power DC Electronic Load AN23600E series adopts a new generation of digital controller, built-in five basic modes as well as seven advanced modes, and also provides serialization function to meet the user's programming, automation testing and other various needs. The product is widely used in fuel cells, grid energy storage, charging piles, photovoltaic, new energy vehicle OBC, servo/server, etc. It is able to efficiently solve the industry's testing difficulties, and has won unanimous praise in the R&D and production tests of many benchmark customers.