Put the battery box on the positioning plate, move the injection device, vacuum, open the injection valve, and complete the injection…… A series of automatic liquid injection operation, such as flowing water smooth, so that the entire lithium battery liquid injection link is very “pleasing to the eye”.

As a key part of the production process of the midsection battery cell, the battery cell injection process connects the upstream winding/lamination stage and the downstream capacitance/formation stage, and the amount of electrolyte injection directly affects the electrochemical performance and safety of the battery. Entering the era of TWh, battery manufacturers put forward higher requirements for injection accuracy, equipment stability and injection speed, and at the same time, it is necessary to consider the safety protection and control of the injection machine.

Safety considerations for lithium giants

At the beginning of 2021, the Time FAW, a joint venture of lithium battery giant Ningde Times, launched a power battery production line expansion project located in Ningde Xiapu Base, with a total investment of 5 billion yuan and construction in two phases, with a corresponding capacity of about 16GWh. As the world’s leading lithium battery supplier, in order to meet the requirements of the international market, Ningde era began to require its production equipment to have safety certification qualifications. In the domestic Xiapu base project, Ningde Times put forward the application requirements of safety products for automatic injection machines to gradually move closer to international standards.

Founded in 2009, Shenzhen Green Sheng Technology Co., LTD. (referred to as Green Sheng) is specialized in the research and development, manufacturing and sales of lithium battery production equipment, and is also the liquid injection equipment provider of Times FAW Xiapu base. Because the automatic injection machine equipment in the process of moving, grabbing and placing, etc., need to use a series of high-speed moving manipulator, motor, cylinder and mechanical guide rail device, which undoubtedly brings the corresponding risk to the operator and equipment. In order to better protect the machine and prevent the misoperation of the battery injector by the operator, after careful screening and evaluation, the Power Technology of Greensson finally selected Pilz’s injector safety solution, which is a combination of the PSEN me5 mechanical safety switch and the PNOZ mB0 programmable safety relay base module. As an internationally renowned mainstream supplier of safety automation technologies and services, Pilz’s solutions are cost-effective and highly targeted, and are well received by users.

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Simple and safe solution

The whole straight line length of the injection machine is close to 10 meters, and even the corner, in order to ensure production safety, it is often necessary to install a large number of safety doors, and achieve both sides of the door. A single injection machine of Greensun needs 7-80 safety doors. In order to ensure that the safety level of the injection machine equipment reaches PLd or above, the experts of PSEN China are equipped with a mechanical safety lock with protective lock PSEN me5 for each safety door. Considering the cost of components, every 5 or so mechanical safety door switches are connected to a programmable safety relay PNOZ MB0 after being connected in series during the design. It meets the above safety level requirements and takes into account the cost, which is a simple and safe solution.

The PSEN me5 integrates the safety door position monitoring and safety protection locking function, which meets the requirements of EN ISO14119. It is an economical safety lock ideal for injection machine applications. It can ensure that the safety protection door of the injection machine is always closed when the dangerous state is not eliminated, and the retention force is up to 1500 N.

In injector applications, the PSEN me5 also offers a different number of independent normally open and normally closed contacts, making the application very flexible, such as the 2-contact access safety controller PNOZ MB0, the 1-contact access standard plc to indicate which door is perfectly adapted to the needs of monitoring the position of the door and protecting the lock. There is no false alarm or shielding of discovered contact series faults due to misoperation of unlock/lock.

As the base unit for the PNOZ multi 2, the PNOZ mB0 is only 45 mm wide and extensible, making it easy for customers to install in the field, and can also be expanded according to the requirements and dimensions of the injector. The PNOZmulti Configurator, a graphical configuration tool, greatly simplified the configuration and diagnosis of the safety system, and the in-line terminals further reduced the wiring workload and made the safety debugging faster. Finally, the power battery production line expansion project was completed ahead of schedule.

With the rapid development of China’s new energy power battery industry, the safety of some key process equipment such as injection machines is bound to receive more and more attention. As an expert in safety automation, Pilmagnetic is able to provide complete solutions for battery equipment manufacturers in China to help users achieve equipment safety in a professional manner.