Lithium batteries are a type of battery that uses lithium metal or lithium alloy as the negative electrode material and uses non-aqueous electrolyte solution.
Due to the very active chemical properties of lithium metal, the processing, storage, and use of lithium metal have very high environmental requirements.
Lithium batteries can be roughly divided into two categories: lithium metal batteries and lithium-ion batteries. Lithium-ion batteries do not contain metallic lithium and are rechargeable.
As the smallest unit of the battery and also the energy storage unit, the cell must have a high energy density to store as much energy as possible,
so that the service life of consumer electronic products and battery durability are better, and electric vehicles can have a longer range. In addition,
the life of the cell is also a very critical factor. Any damage to the cell will cause damage to the entire battery pack. Therefore, during the cell production process,
relevant tests must be carried out to better ensure the quality of the battery.
When testing the battery cells, the testers often need to manually connect the positive and negative electrodes of the battery cells with alligator clips,
and manually scan the barcode with a scanner to record the battery cell information, which increases the battery cell measurement time.
It can be done easily when the quantity is small, but when the test quantity is large, it is necessary to arrange testers to operate one by one.
The low-cost semi-automatic battery cell OCV test device solves this problem well.
OCV testing is a test of the open circuit voltage, AC internal resistance, and shell voltage of the single battery. It is a very important part of the battery production process.
It needs to meet the OCV accuracy of 0.1mv and the shell voltage accuracy of 1mv. The OCV test is used to sort the battery cells. The full name of OCV is open circuit voltage.
The OCV test is mainly to measure the battery characteristics by pressing the probes connected to the voltage tester and the internal resistance tester on the positive and negative ears
of the soft-pack battery. The current OCV test is mainly semi-automatic detection.
The worker manually places the battery in the test device, and the probe of the test device is abutted against the positive and negative ears of the battery,
so as to perform OCV testing on the battery, and then manually unload and sort.
The purpose of testing it is to help detect the performance parameters of the battery and calculate the starting point of the battery SOC. The battery's charge and
discharge state, battery capacity and battery aging condition can be evaluated by measuring the battery's OCV.
Generally speaking, OCV1 refers to the open circuit voltage value measured at t1, and OCV2 refers to the open circuit voltage value measured at t2.
The purpose of the two voltage values tested is to calculate the battery's K value (refers to the voltage drop per unit time of the same battery,
which is used to measure the battery's self-discharge index). K value = OCV1- OCV2, which means the battery's voltage drop from t1 to t2.
The size of the K value is one of the indicators for determining the quality of the battery.
The role of OCV testing:
1. Help customers accurately evaluate the battery's charge and discharge state, battery capacity and battery aging condition, thereby ensuring the best performance of the battery.
2. Can detect abnormal conditions of the battery and inform customers to better maintain the battery.
3. Through testing, you can obtain the OCV values of multiple batteries, better understand the battery's performance parameters, determine whether the battery is effective,
and help customers quickly screen and improve efficiency.
OCV test equipment
OCV test mainly measures battery characteristics by pressing the probes connected to the voltage tester and the internal resistance tester on the positive and negative ears of the soft pack battery.
The current OCV test is mainly semi-automatic detection. The worker manually places the battery in the test device,
and the probe of the test device is abutted against the positive and negative ears of the battery to perform OCV test on the battery, and then manually unloads and sorts it.
OCV test equipment: that is, it can automatically complete the open circuit voltage, AC internal resistance,
and shell cover insulation test (voltage between the positive electrode and the shell) of the single battery in the battery tray. It is an important part of the battery production process.
It is matched with the production process to perform batch testing or single-piece conveyor line testing on the tray to achieve the purpose of fast and reliable detection.
The production management control system automatically calculates the K value according to the test data, automatically completes the binding of production data information,
automatically saves data information and binding information, and transmits the data to the outside through network connection.
Its main process flow includes: automatic incoming materials, code scanning, open circuit voltage measurement, AC internal resistance measurement, shell voltage test, automatic unloading, etc.
Manual material discharge--manual rapid alignment--press test--automatic scanning---battery tester detection----manual removal of products
(1) OCV test--carrier loading
First, place the carrier on the workbench. The workbench is equipped with X/Y limit and positioning blocks, which are generally made of stainless steel and other materials. Pins are used for positioning.
The Y-type push block is used to push and clamp in the X/Y direction, so that the carrier can be positioned and fixed. The clamping power can be a cylinder;
(2) OCV test--test process
The battery cell is placed according to the reference requirements, and the test block is lowered to press the support test block to contact the battery cell ear for testing.
The test block is made of brass material to utilize its excellent conductive properties;
(3) OCV test - battery cell unloading
The upper and lower test blocks are installed on the parts of POM material. The main purpose is to ensure the insulation between the two tabs and the excellent rigidity
and processability of POM material.
Equipment features
1. The equipment can be installed outside the output line or connected inside the line. It is flexible and can be customized on demand.
2. The human-machine interface adopts embedded design. The display height and operating platform are designed according to ergonomic requirements.
3. High-precision test instruments are used, with high accuracy and stable and reliable performance.
4. The OCV tester can be seamlessly connected with the automated logistics equipment and process equipment in the front and rear processes. The test accuracy is high and reliable.