[Manufacturing] - Why do lithium batteries need aging experiments and monitoring? What are the test items?

Electric vehicles are emerging as a prominent trend in the modern transportation industry, and the advent of Lithium batteries plays a crucial role in paving the way for the development of this sector. The aging experiment and aging detection of lithium-ion batteries are to evaluate the EV battery life and performance degradation. These experiments and detections can help scientists and engineers better understand changes in batteries during use and determine the reliability and stability of batteries.
Here are some of the main reasons:
1. Evaluate life: By simulating the cycle charge and discharge process of the battery under different working conditions, the life and service life of the battery can be inferred. By conducting long-term aging experiments, the life of the battery in actual use can be simulated, and the performance and fading capacity of the battery can be detected in advance.
2. Performance degradation analysis: Aging experiments can help determine the performance degradation of the battery during the cycle charge and discharge process, such as capacity decrease, internal resistance increase, etc. These attenuations will affect the battery's charge and discharge efficiency and energy storage capacity.
3. Safety assessment: Aging experiments and aging detection help detect potential safety hazards and malfunctions that may occur during battery use. For example, aging experiments can help discover safety performance under conditions such as overcharge, over-discharge, and high temperature, and further improve battery design and protection systems.
4. Optimized design: By conducting aging experiments and aging detection on batteries, scientists and engineers can help scientists and engineers understand the characteristics and change patterns of batteries, thereby improving the design and manufacturing process of batteries and improving battery performance and lifespan.
In summary, aging experiments and aging detection are very important to understand and evaluate the performance and life of lithium-ion batteries, which can help us better design and use batteries and promote the development of related technologies.

What are the lithium battery aging experiment procedures and project tests?

Through the testing and continuous monitoring of the following performances, we can better understand the changes and attenuation of the battery during use, as well as the reliability, lifespan, and performance characteristics of the battery under specific working conditions.
1. Capacity fading: Capacity fading is one of the main indicators of battery life decline. The aging experiment will periodically perform charge and discharge cycles to simulate the cyclic charge and discharge process of the battery in actual use. Evaluate the degradation of battery capacity by measuring the change in battery capacity after each cycle.
2. Cycle life: Cycle life refers to how many complete charge and discharge cycles a battery can undergo. Aging experiments perform a large number of charge and discharge cycles to evaluate the cycle life of the battery. Typically, a battery is considered to have reached the end of its cycle life when its capacity decays to a certain percentage of its initial capacity (e.g., 80%).
3. Increase in internal resistance: Internal resistance is an important indicator of the battery, which directly affects the battery's charge and discharge efficiency and energy conversion efficiency. The aging experiment evaluates the increase in battery internal resistance by measuring the change in internal resistance of the battery during charge and discharge.
4. Safety performance: The aging experiment also includes the evaluation of the safety performance of the battery. This may involve simulating the reaction and behavior of the battery under abnormal conditions such as high temperature, overcharge, and over-discharge to detect the safety and stability of the battery under these conditions.
5. Temperature characteristics: Temperature has an important impact on battery performance and life. Aging experiments can simulate the operation of batteries under different temperature conditions to evaluate the battery's response and performance to temperature changes.

Why does the internal resistance of a battery increase after being used for a period of time? What will be the impact?

After the battery is used for a long time, the internal resistance increases due to the aging of the battery materials and structure. Internal resistance is the resistance encountered when current flows through the battery. It is determined by the complex characteristics of the internal conductive path of the battery composed of electrolytes, electrode materials, current collectors, electrolytes, etc. The following is the impact of increased internal resistance on discharge efficiency:
1. Voltage drop: Internal resistance will cause the battery to produce a voltage drop during the discharge process. This means that the actual output voltage will be lower than the battery's open circuit voltage, thus reducing the battery's available power.
2. Energy loss: Internal resistance will cause the battery to generate additional heat during discharge, and this heat represents energy loss. Energy loss reduces the energy conversion efficiency of the battery, causing the battery to provide less effective power under the same discharge conditions.
3. Reduced power output: Due to the increase in internal resistance, the battery will have a greater voltage drop and power loss when outputting high current, which will cause the battery to be unable to effectively provide high power output. Therefore, the discharge efficiency decreases and the power output capability of the battery decreases.

In summary, electric vehicles and lithium-ion batteries are playing an increasingly crucial role in modern life. However, to ensure the performance and safety of lithium-ion batteries during use, aging experiments and monitoring are extremely important. Increased internal resistance can reduce the discharge efficiency of the battery, impacting the available energy, output power, and overall performance of the battery. Therefore, reducing the internal resistance of the battery can improve discharge efficiency and battery performance.

EV battery testing solutions at COMIT

To support electric vehicle (EV) manufacturers in the process of reliability testing and quality management, COMIT is a pioneer in providing specialized EV vehicle testing solutions to meet standards. strict requirements of electric vehicles globally, especially the world's WLTP standards and the US EPA, related to Climatic Chamber systems that simulate Temperature, Humidity, and Solar, along with the Road Simulation system that simulates different driving behaviors (Dynamometer) and simulates wind-blowing into the vehicle while driving. In addition, we also provide a rich set of solutions for EV R&D needs as well as testing the features and reliability of EV components that factories produce or purchase from other partners.