WISE Testing Solutions Pvt. Ltd., a privately held company registered as a limited company, aims to provide a comprehensive range of products and services that are valuable throughout different stages of vehicle development and upgrade cycles. WISE represents Michigan Scientific Corporation (MSC) in India, a renowned provider of instrumentation and measurement solutions for various industries, including automotive testing. Their offerings include wheel force transducers, torque sensors, strain gauges, data acquisition systems, and more, which are applicable in the testing and analysis of electric vehicles (EVs). In an interview with Himanshu Vaibhav, a technology journalist at timesev.com, Mayuresh Gaikwad, an Application Engineer at WISE Vehicle Testing Solution, extensively discussed the testing equipment employed for EV batteries, the process of mechanical and electrical testing of EV batteries, and the challenges encountered during the testing process for EV batteries.
TimesEV: Provide comprehensive information regarding the testing equipment utilized in electrical testing.
Mayuresh Gaikwad: Electric vehicle (EV) testing requires specialized equipment to assess the performance, safety, and efficiency of various EV components. Here are some commonly used testing equipment for electric vehicle testing:
- Battery Test Systems: These systems are designed to evaluate the performance and characteristics of EV batteries, including capacity, voltage, current, cycle life, and internal resistance. They can simulate real-world conditions and assess battery health and degradation.
- Electric Motor Dynamometers: Dynamometers are used to measure and evaluate the power output, torque, and efficiency of electric motors used in EVs. They provide data on motor performance under different load conditions and help optimize motor design and control algorithms.
- Charging Station Testers: These testers assess the functionality and safety compliance of electric vehicle charging stations. They verify the charging protocol compatibility, insulation resistance, grounding, communication, and protection features of the charging infrastructure.
- Vehicle Emission Testers: Electric vehicles also need emissions testing to evaluate any potential electromagnetic interference (EMI) or radiofrequency interference (RFI) that could impact other electrical systems. Emission testers measure and analyse the electromagnetic emissions from EVs.
- Thermal Management Systems: These systems monitor and evaluate the thermal characteristics of EV components, such as battery packs, motors, and power electronics. They ensure that proper cooling or heating systems are in place to maintain optimal temperature ranges for efficient and safe operation.
- Vehicle Powertrain Test Benches: These test benches simulate real-world driving conditions to assess the performance, efficiency, and durability of EV powertrain systems. They can replicate various driving scenarios and measure parameters like speed, torque, power output, and energy consumption.
- Vehicle Safety Testing Equipment: EV safety testing involves crash testing, electrical safety evaluations, and overall vehicle structural integrity assessments. Specialized equipment such as crash test dummies, impact sensors, and structural analysis tools are used to ensure EV safety compliance.
- Data Acquisition Systems: These systems collect and analyze data from various sensors and instruments installed in EVs during testing. They enable engineers to monitor and evaluate factors like acceleration, braking, energy consumption, and other performance parameters.
- Vehicle Simulator Software: While not physical equipment, vehicle simulator software is utilized to recreate real-world driving scenarios in a virtual environment. It helps assess the behaviour and performance of EVs under different conditions and enables virtual testing without the need for physical prototypes.
These are some examples of testing equipment used in electric vehicle testing. The specific equipment and tools required may vary depending on the scope of testing, specific components being evaluated, and regulatory standards applicable to the EV industry.
TimesEV: Provide a concise summary of the mechanical testing conducted on electric vehicle batteries.
Mayuresh Gaikwad: Mechanical testing of electric vehicle (EV) batteries involves evaluating their structural integrity, durability, and safety under various conditions. Key tests include:
- Compression Test: Batteries are subjected to controlled pressure to assess their ability to withstand external forces, such as collisions or stacking in transportation.
- Vibration Test: Batteries are exposed to vibrations resembling real-world conditions to ensure their resistance to mechanical stress and assess the stability of internal components.
- Drop Test: Batteries are dropped from specified heights to evaluate their ability to endure impacts, simulate accidents, and prevent damage or leakage.
- Thermal Cycling Test: Batteries undergo repeated heating and cooling cycles to mimic temperature variations during charging, discharging, and environmental conditions. This test ensures battery performance and prevents thermal runaway.
- Penetration Test: Batteries are pierced or impacted with sharp objects to evaluate their resistance to punctures, ensuring safety against external threats.
- Crush Test: Batteries are crushed to simulate extreme conditions, such as vehicle accidents or stacking mishaps, ensuring the prevention of hazardous events like thermal runaways or explosions.
These mechanical tests help manufacturers design and produce EV batteries that meet safety standards, endure real-world usage scenarios, and safeguard against potential hazards.
TimesEV: Provide details about the tests conducted to evaluate a battery’s ability to withstand sudden impacts or collisions.
Mayuresh Gaikwad: To evaluate a battery’s ability to withstand sudden impacts or collisions, manufacturers conduct specific tests that focus on assessing its structural integrity and safety. Here are some details about the tests conducted:
- Mechanical Shock Test: This test involves subjecting the battery to rapid, high-intensity shocks. The battery is typically mounted on a platform, and sudden impacts are applied to simulate collision scenarios. Accelerometers are used to measure the forces experienced by the battery during impact. This test assesses the battery’s ability to resist deformation, withstand sudden accelerations, and prevent internal damage or leakage.
- Combined Environmental Tests: Manufacturers often subject batteries to combined environmental tests that simulate both mechanical impacts and thermal conditions. These tests evaluate the battery’s performance and safety under extreme scenarios, such as collisions combined with temperature variations or thermal abuse. They help identify potential weaknesses or vulnerabilities in the battery design.
Additionally, test like drop test and crash which are explained earlier will also be useful to ensure that electric vehicle batteries can withstand sudden impacts, collisions, and other mechanical stresses while maintaining their structural integrity, preventing safety hazards, and safeguarding the vehicle and its occupants.
TimesEV: Provide detailed information about the test that assesses the battery’s capability to withstand the compression forces that can arise during a vehicle accident.
Mayuresh Gaikwad: The test designed to assess a battery’s capability to withstand compression forces during a vehicle accident is known as the Compression Test. This test evaluates the battery’s ability to resist deformation, maintain structural integrity, and prevent critical failures or safety hazards. Here are some details about this test:
- Test Setup: The battery is securely placed between two rigid plates or fixtures in a controlled testing environment. The plates are then compressed to apply a specified force or pressure to the battery. The compression force may be applied uniformly or targeted to specific areas of the battery to simulate realistic accident conditions.
- Force Measurement: Load cells or force sensors are used to measure the force applied to the battery. These sensors provide accurate readings of the compression force and help assess the battery’s response under pressure. The force is typically measured in Newton or pounds.
- Compression Rate: The compression test may involve applying a constant compression force or subjecting the battery to a specific compression rate. The compression rate determines how quickly the force is applied to the battery. It can be controlled to simulate different accident scenarios, ranging from slow and gradual compression to rapid and intense impacts.
- Deformation Assessment: During the compression test, the battery’s deformation and structural changes are carefully monitored. Visual inspections, strain gauges, or displacement sensors can be used to measure and record any physical alterations, such as changes in shape, bulging, or crushing. These measurements help evaluate the battery’s ability to maintain its structural integrity under compression forces.
- Safety and Performance Evaluation: The compression test assesses the battery’s performance and safety under extreme compression forces. It ensures that the battery can withstand the pressure without rupturing, leaking, or causing hazardous events like thermal runaway. Additionally, the test helps identify potential weak points in the battery design, such as areas prone to deformation or failure, allowing manufacturers to make necessary improvements.
By subjecting batteries to compression testing, manufacturers can validate their ability to withstand the forces generated during vehicle accidents. This test plays a crucial role in ensuring the safety and reliability of electric vehicle batteries by confirming their resistance to compression and minimizing the risk of damage or safety hazards during real-world scenarios.
TimesEV: Provide comprehensive information about the procedure involved in conducting electrical testing for electric vehicle batteries.
Mayuresh Gaikwad: Electrical testing for electric vehicle (EV) batteries involves evaluating their electrical performance, capacity, efficiency, and safety. The following is a comprehensive overview of the procedure involved in conducting electrical testing for EV batteries:
- Initial Preparation: Before conducting electrical tests, the battery is conditioned or brought to a specific state of charge (SOC) as per the test requirements. This may involve fully charging or discharging the battery and allowing it to stabilize at the desired SOC.
- Voltage Measurement: Voltage testing is performed to measure the battery’s open-circuit voltage (OCV), which indicates the battery’s state of charge. It involves using a multimeter or specialized voltage-measuring equipment to directly measure the voltage across the battery terminals.
- Capacity Testing: Capacity testing assesses the battery’s ability to store and deliver electrical energy. This test involves charging the battery to a specified SOC, discharging it at a constant current or load, and measuring the total energy discharged. The discharge profile is monitored to analyze the battery’s voltage, current, and capacity over time.
- Internal Resistance Measurement: Internal resistance testing helps determine the battery’s resistance to the flow of electrical current. It is typically performed by applying a known current to the battery and measuring the voltage drop across the terminals. By using Ohm’s law (V = IR), the internal resistance can be calculated. Lower internal resistance indicates better electrical conductivity and higher efficiency.
- Power Performance Testing: Power performance testing evaluates the battery’s ability to deliver high-power bursts or sustained power output. It involves subjecting the battery to dynamic load conditions, such as rapid charge and discharge cycles, to measure its power capability, voltage response, and overall performance.
- Efficiency Analysis: Efficiency testing focuses on assessing the battery’s energy efficiency during charging and discharging processes. This involves measuring the input and output energy levels and calculating the energy efficiency based on the ratio between them. Higher efficiency indicates reduced energy losses during battery operation.
- Safety Testing: Safety is a critical aspect of electrical testing. Various safety parameters are evaluated, including overvoltage protection, overcurrent protection, thermal protection, and short-circuit protection. These tests ensure that the battery has appropriate safety features to prevent hazards such as overheating, overcharging, or over-discharging.
- Environmental Testing: Environmental conditions, such as temperature and humidity, can significantly impact battery performance. Electrical testing may involve subjecting the battery to extreme temperature environments or thermal cycling to evaluate its behaviour and performance under different operating conditions.
- Data Analysis and Interpretation: Throughout the testing process, data is collected and analysed to assess the battery’s electrical performance, efficiency, capacity, and safety characteristics. The test results are compared against specified standards or performance criteria to determine whether the battery meets the required specifications.
By conducting comprehensive electrical testing, manufacturers can ensure that EV batteries perform optimally, meet safety standards, and deliver the desired power output and energy efficiency. These tests help validate the battery’s electrical capabilities, enabling the development of reliable and high-performing electric vehicles.
TimesEV: Provide a succinct overview of the electrical test employed to estimate the battery’s performance and useful life across multiple charging and discharging cycles.
Mayuresh Gaikwad: The electrical test employed to estimate the battery’s performance and useful life across multiple charging and discharging cycles is known as cycle life testing. This test assesses the battery’s ability to maintain its capacity and performance over repeated charge and discharge cycles. The key features of this test are:
- Test Setup: The battery is subjected to a predetermined charge and discharge profile, simulating real-world usage patterns. This profile specifies the charging and discharging currents, voltages, and durations. The test may include various charge and discharge rates to represent different operating conditions.
- Cycle Count: The battery undergoes a specific number of charge and discharge cycles, typically ranging from several hundred to thousands of cycles. The cycle count depends on the desired estimation of the battery’s useful life under specific conditions.
- Capacity Measurement: At regular intervals during the test, the battery’s capacity is measured. This involves fully charging the battery, discharging it to a specified cutoff voltage, and recording the energy discharged. The capacity is calculated by comparing the energy discharged to the battery’s rated capacity.
- Performance Analysis: The measured capacity values are analyzed over the course of the cycle life test. This analysis helps identify any degradation in the battery’s capacity over time. By monitoring capacity retention, manufacturers can estimate the battery’s useful life and its ability to maintain performance across multiple cycles.
- End-of-Life Criteria: The cycle life test continues until the battery reaches a specified end-of-life criterion. This criterion is often defined as a certain percentage of capacity loss, typically 80% of the initial capacity. Once the battery’s capacity drops below this threshold, the test is considered complete, and the battery is deemed to have reached its estimated useful life.
- Data Analysis: Throughout the cycle life test, data is collected and analysed to evaluate the battery’s performance trends, capacity degradation rate, and cycle life characteristics. This data helps manufacturers assess the battery’s durability, estimate its lifespan, and make improvements in battery design and chemistry.
Cycle life testing provides valuable insights into a battery’s performance and expected lifespan under specific usage scenarios. It helps manufacturers understand how the battery’s capacity degrades over time and plan for battery replacements or maintenance intervals. By conducting cycle life testing, manufacturers can optimize the battery’s design and chemistry to enhance its durability and improve overall battery performance.
TimesEV: Provide a concise overview of the process involved in evaluating and comprehending the electrochemical properties and behaviour of batteries.
Mayuresh Gaikwad: Evaluating and comprehending the electrochemical properties and behaviour of batteries involves a systematic process that helps understand their performance, efficiency, and characteristics. Here is a concise overview of the process:
- Electrochemical Analysis: Electrochemical techniques, such as cyclic voltammetry, impedance spectroscopy, and galvanostatic charge-discharge, are used to study the battery’s electrochemical behaviour. These methods involve applying controlled electrical signals to the battery and measuring the resulting electrochemical responses, including voltage, current, and impedance.
- Electrode Material Characterization: The properties of the battery’s electrode materials, such as the active material composition, surface morphology, and conductivity, are analyzed. Techniques like scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS) help examine the structure and composition of the electrode materials.
- Electrolyte Evaluation: The electrolyte, which facilitates ion transport between the battery’s electrodes, is analyzed to assess its composition, conductivity, and stability. Various spectroscopic and chromatographic techniques can be used to characterize the electrolyte’s chemical composition and performance.
- Capacity Testing: Capacity testing involves charging the battery to its maximum capacity and then discharging it under specific conditions while monitoring the energy or charge transferred. This test helps evaluate the battery’s energy storage capacity and assess its performance and efficiency.
- Rate Capability Analysis: Rate capability testing measures the battery’s ability to deliver power at different charge and discharge rates. By subjecting the battery to varying current levels and evaluating its voltage response and capacity retention, its rate capability and power delivery performance can be assessed.
- Ageing and Degradation Studies: Batteries are subjected to accelerated ageing tests, which involve subjecting them to extreme conditions such as high temperatures or fast charge/discharge rates. The battery’s performance and degradation characteristics are monitored over time to understand its ageing behaviour and estimate its lifespan.
- Data Analysis and Modeling: The data collected from electrochemical analyses and tests are analyzed and interpreted to comprehend the battery’s behaviour. Mathematical models and simulations can be developed to predict battery performance, estimate degradation mechanisms, and optimize battery designs.
By following this process, researchers and manufacturers can gain insights into the electrochemical properties, performance, and ageing behaviour of batteries. This understanding helps improve battery technologies, optimize their usage in various applications, and develop more efficient and durable energy storage solutions.
TimesEV: What are the key challenges encountered by testing engineers during the execution of mechanical and electrical testing for electric vehicle batteries?
Mayuresh Gaikwad: Testing engineers face several key challenges during the execution of mechanical and electrical testing for electric vehicle (EV) batteries. Here are some of the common challenges they encounter:
- Test Standardization: The absence of standardized testing procedures and protocols for EV batteries poses a challenge. As battery technologies evolve, it becomes crucial to establish consistent testing standards that accurately assess battery performance, safety, and durability. The lack of standardization can lead to inconsistencies and difficulties in comparing test results across different laboratories or manufacturers.
- Safety Considerations: Testing EV batteries involves handling high-energy systems that can pose safety risks. Engineers must implement strict safety protocols to ensure protection against thermal runaway, fire, or explosion hazards. Proper training, safety equipment, and controlled testing environments are essential to mitigate these risks effectively.
- Test Equipment and Facilities: Conducting mechanical and electrical tests for EV batteries requires specialized equipment and testing facilities. These may include compression machines, vibration tables, environmental chambers, high-current sources, data acquisition systems, and sophisticated analysis tools. Ensuring the availability and proper calibration of these equipment and facilities can be a challenge for testing engineers.
- Test Duration and Sample Size: Battery testing, especially for evaluating long-term performance and durability, often requires extended test durations. Testing engineers must carefully plan and manage their resources to accommodate the necessary time frames. Additionally, testing a representative sample size of batteries can be challenging due to cost constraints, limited availability, or logistical considerations.
- Complex Test Setup: Mechanical and electrical testing for EV batteries involves setting up intricate test configurations, including precise load application, data acquisition, and control systems. Engineers need to ensure accurate and consistent test conditions to obtain reliable results. Managing the complexity of test setups and minimizing potential sources of errors or inconsistencies is crucial.
- Data Interpretation and Analysis: Analyzing and interpreting the vast amount of data generated during mechanical and electrical testing can be challenging. Engineers need to employ advanced data analysis techniques and modelling approaches to extract meaningful insights, identify trends, and understand the battery’s behaviour accurately.
- Evolving Battery Technologies: The rapid advancements in battery technologies, such as new chemistries or cell designs, present challenges for testing engineers. They need to continuously update their knowledge, stay informed about the latest developments, and adapt testing methodologies to effectively evaluate and validate the performance and safety of emerging battery technologies.
Addressing these challenges requires collaboration among industry stakeholders, research institutions, and regulatory bodies to establish standardized testing procedures, improve safety measures, enhance testing infrastructure, and promote knowledge sharing. Overcoming these challenges enables more accurate and reliable assessment of EV batteries, leading to safer, more efficient, and more durable energy storage systems for electric vehicles.