EV Battery Testing Solutions

As people become more aware of environmental protection, EVs are becoming more and more popular. The value of HEVs and BEVs also depends largely on the power battery and its management technology. The new energy vehicle power battery is the key component in an EV that stores and releases electrical energy to provide continuous power for the EV. This article can be read by beginners who want to buy a used car or test the battery of a new car, as well as by professionals researching batteries. This article analyses the causes of power battery degradation. It explores the testing methods of lithium batteries and medium-sized battery modules to provide relevant practitioners with a reference.

Battery testing methods and use

Lithium-ion and medium-sized battery modules are the two most common types of EV batteries. Testing the performance and safety of power cells is critical to the reliability and safety of electric vehicles. Below are some common battery testing methods and the equipment that may be required:

Capacity Test:

Method: Charge-discharge cycle test to simulate the life of the battery in actual use

Instrument: Battery Test Chamber

The battery test chamber is dedicated to the testing of lithium battery products. With customized battery bracket and multiple temperature protection functions, it provides control for long continuous work, multiple temperature points, and frost free.

Advantage:

1. It can carry out large-scale, automated battery performance testing and is suitable for production lines.

2. Highly controllable charging and discharging conditions to simulate different usage scenarios.

3. Capable of real-time battery performance monitoring, capacity testing and cycle life testing.

Internal resistance measurement:

Methods: Measurement of the internal resistance of a cell by voltage and current response.

Apparatus: Electrochemical workstation

Advantage:

1. Highly flexible and can be used for a wide range of electrochemical tests.

2. Capable of measuring a wide range of electrical parameters such as potential, current and conductivity of cells.

3. Provides in-depth analysis of electrode and electrolyte properties.

Electrochemical impedance spectroscopy measurements:

Method: Measurement of electrochemical parameters such as resistance and capacitive resistance of the battery by frequency response.

Instrument: Electrochemical Impedance Spectroscopy, EIS

Advantage:

1. Provides frequency-domain information that allows analysis of parameters such as resistance, capacitive reactance and phase angle of the battery.

2. Ideal for studying electrochemical processes within the battery.

3. Capable of detecting interface and electrode reaction problems that may exist in a battery system.

X-ray diffraction analysis:

Methods: Analysis of changes in crystal structure in cells.

Apparatus: X-ray diffractometer

Advantage:

1. Provides information about the crystalline structure of battery materials.

2. Capable of analysing crystal defects and phase transitions in electrode materials.

3. Plays a key role in materials research, helping to understand battery performance and failure mechanisms.

Battery Voltage Measurement:

Method: Using the voltage measurement function of the multimeter, you can measure the open circuit voltage of the battery. This is a simple method for determining whether the battery is charging properly.

Instrument: Multimeter

Advantage:

1. Small, lightweight and easy to carry and use. This makes it a convenient tool for battery testing in the field or in emergency situations.

2. The simple user interface and operating procedures make it easy to perform basic battery measurements even for non-experts.

Electronic load test:

Method: Simulates the performance of a battery under different loads.

Equipment: Electronic load

Advantage:

1. Ability to simulate battery load conditions in real-world applications.

2. Allows dynamic load adjustment to simulate different load conditions.

3. Can work independently of the power supply, suitable for power failure or unstable power supply.

EV Battery Decay Cause Analysis

EV battery is composed of several single batteries connected in parallel and series, and the performance of power battery depends on the consistency of the capacity and internal resistance of single batteries. There are several reasons for power battery degradation.

1. Production process

   The inconsistency of monomer battery itself is mainly due to the imperfection of preparation process and sorting technology. To ensure the consistency of the monomer battery, the uniformity of the positive electrode, negative electrode materials, and electrolytes is very demanding, and inconsistency of raw materials will lead to inconsistency of the monomer battery.

2. Temperature factor

   Due to the limitations of the power battery layout space, it is difficult to ensure that all the monomer batteries are in a completely consistent environment during the integration design of the power battery. From a comprehensive point of view, vehicles with water-cooled battery body wrapping technology are more conducive to overcoming the influence of temperature factors than vehicles with simple air-cooled battery bodies.

3. Usage Habits

   Some people like to accelerate sharply when driving, resulting in long-term high-current discharge of the power battery, which accelerates the internal changes in the power battery; some people like to wait until the power battery is exhausted before charging, resulting in deep discharge of the power battery, which leads to power battery attenuation; in addition, due to the limitations of the charging conditions, some owners can only choose to fast-charging, resulting in the vehicle being in the charging state of the long term high-current, which accelerates the decay of the power battery. These all accelerate the attenuation of the power battery.