With the wide application of lithium ion batteries in electronic equipment, electric vehicles and energy storage systems, the performance and safety of batteries have become a topic of great concern to users and manufacturers. The battery may suffer various physical damages in the process of use, among which acupuncture is a typical damage method that simulates the battery being punctured by sharp objects. As a standard safety evaluation method, battery acupuncture test is widely used in battery design verification and quality control, aiming at simulating internal short circuit under extreme conditions, evaluate the safety and endurance of the battery. This article will introduce in detail the principle, testing process, key parameters and its important role in battery safety assessment of battery acupuncture test.

I. Basic principles of battery acupuncture test

the core of battery acupuncture test is to use a needle of a specific size to penetrate the inside of the battery at a certain speed to simulate the internal damage that may occur when the battery is punctured by sharp foreign bodies. The acupuncture process may lead to the rupture of the battery diaphragm, causing direct contact between the positive and negative electrodes, leading to internal short circuit, resulting in thermal runaway. This test simulating extreme damage helps to reveal the safety risks of batteries after mechanical damage.

Through acupuncture test, we can observe whether the battery will burn, explode, smoke and other dangerous phenomena, as well as the changes of battery voltage and temperature. The test results can provide the basis for battery design optimization and help improve the safety protection performance of the battery.

II. Testing process of acupuncture test

the battery acupuncture test process usually includes the following steps:

1. Test preparation

first, select the appropriate specification according to the test standard. Battery sample, and ensure that the battery is in a specific state, such as full power or a specific charging and discharging state. The test environment should be kept stable and usually carried out in a well-ventilated safety laboratory.

2. Fixture installation

fix the battery on a special fixture to ensure that the battery position is stable and the needle can accurately penetrate into the specified part of the battery. The fixture design should ensure that the battery cannot move due to acupuncture force to avoid deviation of test results.

3. Acupuncture action

the needle is controlled to penetrate the battery at a specified speed and force through mechanical devices. The diameter, length and shape of the needle are usually in accordance with relevant standards to ensure the repeatability and scientificity of the test.

4. Data collection

5. Result recording and analysis

if the battery smoke, burning or explosion occurs during the test, it should be recorded immediately. After the test is completed, the data is analyzed to evaluate the safety performance of the battery and the damage after acupuncture.

III. Key test parameters and their significance

battery acupuncture test involves many key parameters, which directly affect the scientificity of the test and the accuracy of the results.

1. Needle size

the diameter and shape of the needle determine the degree of damage when piercing the battery. Common needle diameters range from 2 to 5mm. Needles of different sizes are used to simulate penetration damage of different degrees.

2. Penetration speed

The speed of needle penetration affects the probability of internal short circuit. Faster penetration speed may lead to more severe internal damage and thermal runaway reaction, usually the test speed is controlled at several millimeters per second.

3. Battery status

the battery power state has a significant influence on the acupuncture test results. In the state of full power, the internal energy of the battery is relatively high, and the thermal reaction caused by short circuit is more intense. Therefore, acupuncture tests are mostly conducted in the state of full power.

4. Test environment

temperature, humidity and ventilation conditions all affect the performance of the battery during acupuncture. The standard test environment is generally kept at room temperature and dry to avoid external environment interfering with the test results.

IV. Importance of battery acupuncture test

the importance of battery acupuncture test is reflected in the following aspects:

1. Security performance verification

acupuncture test can simulate the battery suffering from internal short circuit caused by sharp object puncture, and check the safety of the battery under extreme mechanical damage.Full performance. Through the test, it can be confirmed whether the battery has the ability to prevent thermal runaway and fire explosion.

2. Design improvement basis

the test results help design engineers find the weak links in battery structure and materials. For example, the puncture resistance of diaphragm and the stability of positive and negative electrode materials can be optimized according to acupuncture Test feedback.

3. Quality control and certification

as an important part of safety assessment, acupuncture test is a necessary test item in many battery certification standards. Only by passing the qualified acupuncture test can Battery products obtain the market access qualification and ensure the safety of end users.

4. Improve user confidence

as a product with high energy density, users pay more and more attention to safety. The battery verified by acupuncture test can gain market recognition and enhance users' confidence in the safety performance of the product.

V. Safety protection measures in acupuncture test

Due to the possibility of battery burning or explosion caused by acupuncture test, strict safety measures must be taken during the test:

• isolation protection
  the test area shall be equipped with explosion-proof and fire-proof isolation facilities to avoid damage to personnel and equipment caused by abnormal events.

• Ventilation equipment
  ensure air circulation in the test environment and eliminate possible harmful gases in time.

• Remote operation
  the remote control and monitoring system is adopted to reduce the close contact between testers and high-risk equipment.

• Emergency plan
  equipped with fire extinguishing equipment and emergency treatment plan to ensure quick response in case of fire.

6. Common problems and precautions

when conducting battery acupuncture test, pay attention to the following points to ensure the accuracy and safety of the test:

• confirm that the battery status meets the test requirements to avoid overcharging or overdischarging affecting the results.
• Record abnormal phenomena and parameter changes in time for subsequent analysis.
• After the test, clean up the equipment and environment to prevent residual chemicals or fire hazards.

As an important means to evaluate the performance and safety of lithium ion batteries, battery acupuncture test reveals the risks of short circuit and thermal runaway in the battery by simulating the extreme conditions when the battery is punctured by sharp objects. Its scientific and reasonable testing process and rigorous parameter control make acupuncture testing a key link in battery safety certification and design optimization. Through acupuncture tests, manufacturers can effectively identify and prevent potential safety hazards of batteries, improve product quality and user safety.