【Omron industry case】Application of high-end pouch battery welding machine

Process introduction

In the middle process of the secondary battery, the battery welding machine first needs to quickly heat press the battery cells after winding/lamination to achieve cell compaction, and then ultrasonic welding of the positive and negative tabs of the battery cells.

【Omron industry case】Application of high-end pouch battery welding machine

　　problem

1. The pressure fluctuates greatly, resulting in poor wrapping or insufficient liquid filling

At present, the pressure fluctuation is controlled at about 10%, resulting in a large deviation in the thickness of the cell, and when the actual thickness of the cell is larger than the requirement, there will be poor wrapping in the subsequent packaging; When the thickness of the cell is thinner than required, the cell will have insufficient electrolyte injection at the injection site.

2. The safety protection level of the equipment is not up to standard, and there are potential safety hazards

In order to create a safer working environment for employees (according to OSHA requirements), avoid accidents, and launch the equipment on the EU market with higher safety standards, effective safety measures need to be implemented for the equipment to achieve a safety protection level of D.

solution

1. Effectively control pressure fluctuations through PID optimization

Conventional PIDs are prone to overshoot or long settling times, so they need to be optimized for existing PIDs.

　　Optimized PID closed-loop control model:

At the transition point, reduce the speed of the equipment to control the pressure fluctuation and not let the pressure change too much; After reaching a certain pressure value, the PID control is switched to achieve a pressure fluctuation of ≤5% and a shorter stability time.

　　2. According to the 4 steps, formulate targeted safety protection measures

Security protection is mainly divided into 4 steps:

1. Risk identification

2. Risk assessment

3. Safety protection measures

4. PL grade assessment.

First of all, the risk identification of welding machines mainly includes the following aspects:

Hot press servo at the hot pressing station:

It is possible to squeeze people when hot pressing is pressed;

At the welding machine station, there is a risk of contact when the welding machine is welding;

Accidental entry of personnel into the equipment may cause collision;

When the robot picks up and unloads materials, it may squeeze people;

At the turntable station, there is a risk of colliding with people when the turntable is moving;

Secondly, risk assessment, in order to solve the risk points of the robot, the evaluation table based on ISO13849-1 (GB/T16855.1) is shown in the figure below:

　　Third, safety protection measures are mainly implemented in three aspects:

Safety redundancy circuit design:

Dual-channel input/output is used to form a redundant loop, and the category level of the hardware loop is improved

Increase the MTTFd value:

According to the actual operation of the equipment, the components that meet the requirements of B10d are adopted;

Improving Diagnostic Coverage:

Reasonable inspection, use of normally open and closed mechanical contacts, use of dynamic testing.

Finally, the PL rating is calculated according to the safety design scheme of the welding machine (IS013849-1:2006 risk calculation standard), and the rating of the lowest safety loop (single safety function) is taken as an example.

　　Control system

● Mechanical automation controller NJ/NX series

● AC servo system 1S series

● Safety control unit NX series

● Image processing system FH series

● SCARA Robot Cobra 450/650 series

● Safety light curtain F3SG-SR/PG series

　　Deliver value

1. Pressure fluctuation ≤5%

2. Equipment security level = D level

【Management】

■ In the context of the rapid development of the secondary battery industry, we can quickly respond to market changes, greatly upgrade the performance of the equipment by improving the pressure control accuracy of hot pressing and the safety protection level of the overall equipment, and strive to create a new standard in the industry and become the law of winning in the competition.

【Management】

■ The improvement of the accuracy of hot pressure control is completely based on the optimization of the control system and program, without changing the mechanical structure and movement time, and the introduction time is faster and the cost is lower.

■ Through targeted safety protection measures, the safety level that meets the requirements is realized, the personal safety of on-site operators is ensured, the efficiency of the welding machine is improved, and the product quality is guaranteed.

【Engineer Layer】

■ From PLC, image processing, servo, robot to security, Omron provides a full set of products, solutions and technical support, communication is barrier-free, and later maintenance is simpler.

■ Omron engineers participate in the whole process of guidance, and the later project is adjusted, and you only need to modify the parameters by yourself.

Article source: Omron Industrial Automation Information Account

【Omron industry case】Application of high-end pouch battery welding machine

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