An electrolyte automatic mixing system and an automatic mixing method thereof

Abstract

This invention relates to an automatic electrolyte mixing system and method, comprising: multiple solvent metering units; at least one mixing and filling module; an intermediate pipeline connecting the solvent metering units and the mixing and filling module in parallel; a glove box connected to a weighing and preparation vessel via a feeding pipeline; a circulating rinsing pipeline, with its circulating pump inlet connected to the terminal filter outlet and its outlet connected to the top of the weighing and preparation vessel, and connected to the glove box feeding pipeline via a tee; and a nitrogen pipeline with three branches: one for pressurizing the solvent, one for purging filling residues, and one for maintaining a slight positive pressure in the glove box. This invention achieves high-precision metering, zero waste, and fully automated mixing through nitrogen pressurizing of the solvent, reverse flushing of the inner wall of the salt addition pipeline via the circulating rinsing pipeline, and nitrogen purging of residues after filling, thereby improving production efficiency and safety.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery manufacturing technology, specifically to an automatic electrolyte mixing system and its automatic mixing method. Background Technology

[0002] Electrolyte is a core component of lithium-ion batteries, and its performance directly affects the battery's capacity, cycle life, and safety. Electrolytes are typically composed of various organic solvents such as ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and propylene carbonate (PC), as well as lithium salts such as lithium hexafluorophosphate (LiPF6) and various functional additives, mixed in specific proportions. The physicochemical properties of different solvents vary significantly. For example, ethylene carbonate (EC) requires temperature-controlled storage, while dimethyl carbonate (DMC) and diethyl carbonate (DEC) are highly sensitive to moisture. Some additives require refrigeration. This places high demands on material management, environmental control, and metering accuracy in the mixing system.

[0003] Currently, electrolyte mixing and production mostly employs semi-manual or fully manual operations. Specifically, operators manually weigh various solvents and lithium salts according to the formulation requirements, then transfer them separately to a mixing tank for stirring, mixing, and settling, before finally filling them into finished product containers. The aforementioned existing technology has the following shortcomings: 1. Low metering accuracy and unstable product quality: Manual weighing and transportation are prone to errors due to factors such as operator skill and fatigue, which can cause the proportions of each component to deviate from the formula requirements, ultimately affecting the consistency of the electrolyte and battery performance.

[0004] 2. Low efficiency and difficulty in meeting the needs of large-scale production: Weighing and transferring multiple solvents one by one takes a long time, and cleaning containers and pipelines is required when switching between different formulations, which further prolongs the production cycle.

[0005] 3. Significant material waste and increased costs: Leaks and residues are inevitable during manual operation, and residual solvents or electrolytes in the pipelines are difficult to recover, resulting in raw material waste and increased production costs.

[0006] 4. Potential safety hazards and environmental pollution risks: Some organic solvents and lithium salts are corrosive, toxic or flammable. Direct contact or exposure during operation can easily lead to safety accidents, and volatile gases may pollute the environment.

[0007] 5. Lack of dynamic control over storage conditions for different solvents: Existing systems often use a uniform storage method for all solvents, which cannot meet the differentiated requirements of EC, such as the need for heat preservation and the need for refrigeration of certain additives, thus affecting the quality of raw materials.

[0008] Therefore, there is an urgent need for a system that can automate and precisely mix various solvents and lithium salts to overcome the shortcomings of manual operation, improve production efficiency, product quality and safety, and reduce waste and costs. Summary of the Invention

[0009] This invention designs an automatic electrolyte mixing system and its automatic mixing method. The technical problem it solves is to overcome the defects of existing electrolyte mixing processes, such as large measurement errors, low efficiency, serious material waste, safety hazards, and inability to meet the differentiated storage conditions of different solvents caused by manual weighing and transportation of multiple solvents and additives.

[0010] To solve the aforementioned technical problems, the present invention adopts the following solution: An automatic electrolyte mixing system includes: multiple solvent metering units, each solvent metering unit consisting of a solvent tank, a filter and a weighing metering tank connected in series, the outlet of the solvent tank being connected to the inlet of the filter via a pipeline, the outlet of the filter being connected to the inlet of the weighing metering tank via a pipeline, and the outlet of the weighing metering tank being connected to an intermediate pipeline via a pipeline. At least one mixing and filling module, each mixing and filling module is composed of a weighing and preparation vessel, a terminal filter, a regulating valve and a filling connector connected in series. The bottom outlet of the weighing and preparation vessel is connected to the inlet of the terminal filter, the outlet of the terminal filter is connected to the inlet of the regulating valve, and the outlet of the regulating valve is connected to the filling connector. The outlets of the plurality of solvent metering units are connected in parallel to the inlet of the at least one mixing and filling module via the intermediate pipeline. The glove box is connected to the top inlet of one or more of the weighing and configuration vessels via a sealed feeding pipeline; The circulating rinsing pipeline includes a circulating pump and connecting pipelines. The inlet of the circulating pump is connected to the outlet of the terminal filter, and the outlet of the circulating pump is connected to the top circulation return port of the weighing and preparation vessel through a pipeline. A tee is provided on the pipeline between the outlet of the circulating pump and the top of the weighing and preparation vessel. The tee is connected to the feeding pipeline of the glove box to form a return loop in which the material flows in reverse through the feeding pipeline. The nitrogen pipeline has three branches: the first branch is connected to the top of each solvent tank for pressurizing the solvent; the second branch is connected to the filling pipeline between each regulating valve and the corresponding filling connector for purging residual electrolyte; and the third branch is connected to the gas replenishment port of the glove box for maintaining a slightly positive pressure nitrogen atmosphere inside the glove box.

[0011] Preferably, there are multiple weighing and configuration vessels and multiple mixing and filling modules arranged in parallel. The outlets of the multiple solvent metering units are connected to the inlets of the multiple mixing and filling modules through the intermediate pipeline.

[0012] Preferably, the terminal filter serves as both a dynamic filter during cyclic rinsing and a final filter before filling.

[0013] Preferably, the glove box is a slightly positive pressure nitrogen-protected box, with a precision electronic balance and a feeding funnel inside, and the water and oxygen content inside is controlled below 1 ppm.

[0014] Preferably, the first branch of the nitrogen pipeline is equipped with a pressure reducing valve and a pneumatic ball valve, the second branch is equipped with a pressure reducing valve and a pneumatic ball valve, and the third branch is equipped with a pressure reducing valve and a ball valve.

[0015] It also includes a fourth nitrogen branch, which is led out from the main nitrogen pipe, passes through a pressure reducing valve and a pneumatic ball valve, and is connected to the circulating washing pipeline between the outlet of the circulating pump and the feeding pipeline of the glove box; the top of the weighing and preparation vessel is also equipped with an exhaust valve and a pressure sensor.

[0016] A method for automatically mixing electrolytes using the system includes the following steps: Step 1: Nitrogen gas is introduced into the top of the solvent tank through the first branch of the nitrogen pipeline. The solvent is then pressurized through the filter and the weighing tank to the intermediate pipeline, and then sent to the weighing preparation vessel through the intermediate pipeline. After the solvent enters the weighing preparation vessel, it is re-weighed by its weighing sensor. The re-weighed value is compared with the value measured in the weighing tank to confirm that all the solvent in the pipeline has been added to the preparation vessel. Finally, the total amount of solvent added is precisely controlled by the weighing sensor of the weighing preparation vessel. Step 2: Manually weigh the lithium salt and / or additives inside the glove box and add them to the weighing and preparation vessel through a closed feeding pipeline; Step 3: Start the circulating flushing pipeline so that the material in the weighing and mixing vessel passes through the terminal filter and the circulating pump, and then flows in reverse through the feeding pipeline of the glove box via the three-way valve, flushing the material remaining on the inner wall of the feeding pipeline back to the weighing and mixing vessel. Step 4: Start the stirrer in the weighing and mixing vessel to obtain the electrolyte; Step 5: Fill the packaging barrel with electrolyte through the terminal filter, regulating valve and filling connector. After filling, introduce nitrogen into the filling pipeline through the second branch of the nitrogen pipeline to blow the residual electrolyte into the packaging barrel.

[0017] Preferably, in step 3, before starting the circulating rinsing pipeline, the feeding pipeline is briefly purged through the nitrogen pipeline to push the free droplets into the weighing and preparation vessel.

[0018] Preferably, in step 5, the filling process adopts a two-stage control: first, filling at the maximum flow rate to 95% of the set capacity, then reducing the flow rate to fill to more than 99%, and finally purging the residue with nitrogen.

[0019] Preferably, in steps 1 and 2, the weighing sensor of the weighing configuration vessel accumulates the total weight, and the control system automatically verifies the integrity of the feeding.

[0020] Compared with existing technologies, the automatic electrolyte mixing system and its automatic mixing method have the following advantages: (1) This invention sets up a solvent metering unit consisting of a solvent tank, a filter, and a weighing and metering tank to independently weigh and meter each solvent, and combines the total weight feedback of the weighing and configuration vessel to achieve dual metering verification. The entire solvent delivery process is completed by nitrogen pressure delivery, avoiding errors caused by manual weighing and transfer, ensuring that the proportions of each component accurately meet the formulation requirements, and significantly improving the consistency of the electrolyte and battery performance.

[0021] (2) This invention features a circulating rinsing pipeline, with the glove box's salting pipeline connected to this circulating pipeline via a tee. After each feeding, the circulating rinsing is initiated, utilizing the reverse flow of material from the preparation vessel through the salting pipeline to flush all residual lithium salts or additives from the inner wall back into the vessel, achieving complete recovery of trace additives. Simultaneously, after filling, nitrogen purging pushes the residual electrolyte in the tubing into the packaging barrel. The combination of these two methods eliminates material waste at the source and reduces production costs.

[0022] (3) The three branches of the nitrogen pipeline of the present invention respectively realize the clean pressure delivery of solvent without pump, the zero-drip purging after filling, and the glove box micro-positive pressure protection, and the entire process is closed operation, so that personnel do not directly contact the chemicals. The glove box controls the water and oxygen content at an extremely low level to prevent the generation of corrosive gases by lithium salt hydrolysis.

[0023] (4) By adding a nitrogen auxiliary branch, the present invention introduces nitrogen pulses to form a gas-liquid two-phase flow in the circulating rinsing, which significantly enhances the stripping effect on the residue on the inner wall of the feeding pipeline, and blows the pipeline dry with nitrogen after rinsing to effectively prevent crystallization blockage; at the same time, combined with the weighing difference adaptive selection of the rinsing mode, nitrogen and time are saved and production costs are reduced. Attached Figure Description

[0024] Figure 1 : A schematic diagram of the partial component arrangement of the automatic electrolyte mixing system of the present invention; Figure 2 : A schematic diagram of the connections of the components of the automatic electrolyte mixing system in Embodiment 1 of the present invention; Figure 3 : A schematic diagram of the connection of each component of the automatic electrolyte mixing system in Embodiment 2 of the present invention.

[0025] Explanation of reference numerals in the attached figures: 1—Solvent tank; 2—Filter; 3—Weighing and mixing vessel; 4—Glove box; 5—Fourth nitrogen branch. Detailed Implementation

[0026] The following is combined Figures 1 to 3 The present invention will be further described as follows: Example 1

[0027] like Figure 1 As shown, the automatic electrolyte mixing system of the present invention includes: multiple solvent tanks 1, multiple filters 2, multiple weighing and mixing tanks 3, and a glove box 4.

[0028] There are multiple solvent tanks 1, each used to store various solvents required for electrolyte preparation, such as ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (EMC), and propylene carbonate (PC). Each solvent tank 1 is equipped with an insulation jacket, a refrigeration jacket, or ambient temperature storage conditions, depending on the physicochemical properties of the solvent it stores. The outlet of each solvent tank 1 is connected to the corresponding filter 2 via an independent pipeline.

[0029] There are also multiple filters 2, each installed on the pipeline between each solvent tank 1 and the weighing and preparation vessel 3, for primary or multi-stage filtration of the solvent to remove particulate impurities and ensure the purity of the final electrolyte.

[0030] Multiple weighing and preparation vessels 3 constitute the core equipment for electrolyte mixing. Each vessel has multiple inlets at its top, connected to the filtered pipelines of each solvent tank 1 and the outlet pipeline of the glove box 4. Weighing sensors are installed at the bottom of each weighing and preparation vessel 3 to monitor the total weight of the materials inside in real time. An agitator is installed inside each weighing and preparation vessel 3, and heating / cooling jackets and temperature sensors can be configured according to process requirements. An outlet is also located at the bottom of each weighing and preparation vessel 3 to transport the prepared electrolyte to downstream filling equipment (not shown in the figure).

[0031] Glove box 4 is a sealed, slightly positive-pressure operating chamber filled with high-purity nitrogen, equipped with a precision electronic balance and a feeding funnel. Glove box 4 is used for the manual and precise weighing of lithium salts such as lithium hexafluorophosphate (LiPF6) and trace amounts of functional additives in an anhydrous and oxygen-free environment, followed by addition to the weighing and preparation vessel 3 via a sealed pipeline. The moisture and oxygen content inside glove box 4 is controlled below 1 ppm to ensure the stability of the lithium salts.

[0032] In addition, glove box 4 is equipped with an additive container for storing lithium salts. This sealed container is used to temporarily store lithium salts such as lithium hexafluorophosphate (LiPF6) under a slightly positive nitrogen atmosphere within the glove box, allowing operators to easily access and weigh them within the glove box. The outlet of this additive container is connected to the top inlet of the weighing and preparation vessel 3 via the sealed feeding pipeline. A pressure regulating valve is installed on the main nitrogen pipeline, located before the bifurcation point of the three nitrogen branches. This valve is used to regulate the inlet pressure of the main nitrogen pipeline, providing a stable gas source for the subsequent three branches. Each branch is also equipped with a pressure reducing valve for precise pressure regulation. Through the cooperation of this pressure regulating valve and the pressure reducing valves of each branch, the internal pressure of the glove box is ensured to remain stable within a slightly positive pressure range, such as 0.1-0.3 MPa, while ensuring stable gas pressure in the pipeline and complete material transfer during the feeding process.

[0033] like Figure 2 As shown, the specific piping connections between the components are as follows: The bottom outlet of each solvent tank 1 is connected to the inlet of a corresponding filter 2 via an independent conveying pipeline. The outlet of filter 2 is then connected to the corresponding inlet of the weighing and metering tank via a pipeline. In other words, each solvent conveying path consists of an independent solvent tank, filter, and weighing and metering tank connected in series to form a solvent metering unit. The pipelines for different solvents do not intersect before entering the weighing and mixing vessel 3.

[0034] Filter 2 is installed on the pipeline between solvent tank 1 and weighing tank. Figure 2 The diagram clearly shows that each filter 2 is independently connected in series downstream of its corresponding solvent tank 1 to filter the solvent before it enters the weighing and metering tank, removing particulate impurities. The weighing and metering tank ensures precise and controllable quality of each solvent entering the weighing and metering vessel 3.

[0035] The mixing and filling module includes a weighing and mixing vessel, a terminal filter, a regulating valve, and a filling connector, which is used to mix, filter, regulate the flow rate, and fill various solvents and additives into packaging barrels.

[0036] The bottom outlet of the weighing and preparation vessel 3 is connected to the inlet of the terminal filter via a pipeline. The terminal filter is used for final filtration of the prepared electrolyte, removing any particles or impurities to ensure the cleanliness of the finished product. The outlet of the terminal filter is directly connected to the inlet of the regulating valve via a pipeline. A weighing sensor is installed on the body of the weighing and preparation vessel 3 to measure the total weight of the materials inside the vessel in real time.

[0037] The regulating valve, either pneumatic or electric, is used to control the filling flow rate, achieving precise filling with a fast initial flow followed by a slower flow. The outlet of the regulating valve is connected to the inlet of the filling connector, i.e., the inlet of the quick-connect filling connector, via a flexible or rigid pipe. The filling connector is used for quick docking with the feed inlet of the packaging drum to achieve a sealed filling.

[0038] There are multiple solvent metering units and multiple mixing and filling modules. The multiple solvent metering units are set in parallel, and the multiple mixing and filling modules are also set in parallel. The outlet of the multiple solvent metering units is connected to the inlet of the multiple mixing and filling modules through an intermediate pipeline.

[0039] The system also includes a glove box 4 connected to a dedicated feed port on the top of the weighing and preparation vessel 3 via a separate, sealed feeding pipeline. Alternatively, it can be connected to an intermediate pipeline and ultimately deliver the lithium salts or additives to the weighing and preparation vessel 3. The glove box 4 contains a feeding funnel and a precision balance. Operators manually add the weighed lithium salts or additives to the weighing and preparation vessel 3 through this sealed pipeline. The feeding pipeline is equipped with manual or pneumatic valves to control the feeding flow.

[0040] When preparing the electrolyte, according to the formula requirements, the discharge valves of one or more corresponding solvent tanks 1 are opened sequentially. The solvent is filtered through filter 2 and then enters the weighing and metering tank. After weighing and metering, it enters the weighing and preparation vessel 3. The weighing sensor in the weighing and preparation vessel 3 provides real-time weight feedback, and the corresponding valve is closed after the set value is reached. For lithium salts and trace additives, the operator weighs them in the glove box 4 and then adds them to the weighing and preparation vessel 3 through a closed feeding pipeline. After all materials have entered the weighing and preparation vessel 3, the stirrer is started for mixing, and the final product electrolyte is obtained.

[0041] It also includes a circulating rinsing pipeline, whose core function is to circulate, filter, and uniformly mix the electrolyte in the reactor. This loop can also be used to rinse the terminal filters and pipelines. It includes intermediate pipelines, multiple weighing and preparation reactors, multiple terminal filters, a circulating pump, and connecting pipelines between them. Rigid or flexible pipes are used for connection, and circulating discharge valves are installed on the pipelines to control whether material in the reactor enters the circulating loop. This section of pipeline is usually shared with the normal filling discharge pipeline, but in circulating mode, the valve on the filling branch is closed. The outlet of the terminal filter is directly connected to the suction port of the circulating pump. The terminal filter performs both circulating filtration and pre-filling filtration, serving a dual purpose and improving cleanliness. The circulating pump is typically a centrifugal pump or diaphragm pump, providing power for the circulation. The outlet pipeline of the circulating pump is connected via intermediate pipelines to a dedicated circulating return port or feed / inlet at the top of each weighing and preparation reactor. Check valves and pneumatic ball valves can be installed on this pipeline to prevent backflow.

[0042] In addition, the glove box's salt addition line is connected via a T-junction to the circulating rinse line between the circulating pump and the weighing and mixing vessel. The circulating rinse line, through the glove box's salt addition line, uses the salt addition line as a return channel, allowing the material to flow backward through the salt addition line, flushing the inner wall and carrying any residual material back to the weighing and mixing vessel. After each addition, the circulating rinse is initiated to flush all residual material from the inner wall of the line into the mixing vessel, ensuring formula accuracy, line cleanliness, preventing crystallization blockage, and eliminating waste.

[0043] The system also includes a nitrogen pipeline with three branches: the first branch is connected to the top of each solvent tank 1 for pressurizing the solvent; the second branch is connected to the filling pipeline between each regulating valve and the corresponding filling connector for purging residual electrolyte, achieving zero dripping during filling and reducing material waste; and the third branch is connected to the air supply port of the glove box 4 for maintaining a slightly positive pressure nitrogen atmosphere inside the glove box.

[0044] Nitrogen line branch one introduces nitrogen into the top of the solvent tank, creating positive pressure that forces the solvent into the solvent line, through the outlet, filter, and weighing tank, achieving clean, pump-free delivery. After filling, nitrogen line branch two introduces low-pressure nitrogen into the section between the filling connector and the regulating valve, pushing the residual electrolyte into the packaging container, achieving zero dripping and precise filling. Nitrogen line branch three continuously supplies nitrogen into the glove box, maintaining a slightly positive pressure, anhydrous, and oxygen-free environment to ensure that the lithium salt additive does not hydrolyze during manual feeding.

[0045] This system also includes a PLC control system. The PLC control system is electrically connected to each pneumatic ball valve, regulating valve, circulating pump, weighing sensor, pressure transmitter, temperature sensor, and the pneumatic valve of the nitrogen pipeline. The PLC control system performs the following automatic controls: sequentially opening or closing the corresponding pneumatic ball valves according to the formula requirements to achieve solvent pressure delivery and metering; controlling the start and stop of the circulating pump and the valve switching of the circulating rinsing pipeline to achieve automatic rinsing of the salt addition pipeline; during the filling stage, receiving the weight signal from the filling platform scale and controlling the opening of the regulating valve through a PID algorithm to achieve two-stage filling, first fast and then slow; after filling, controlling the opening of the nitrogen purging valve to purge residual electrolyte. Through the above controls, this system achieves fully automated operation of the entire process of solvent pressure delivery, weighing and metering, mixing and stirring, circulating rinsing, and automatic filling.

[0046] Appendix Figure 2 Although no valves are individually labeled, necessary control valves, such as pneumatic ball valves, regulating valves, and nitrogen purging interfaces, can be installed on each pipeline as required by the invention. These auxiliary components are designed by those skilled in the art based on the appendix. Figure 2 The basic connection relationships shown can be reasonably expanded with additional content.

[0047] Taking the preparation of a batch of electrolyte as an example, this system operates under the automatic control of the PLC control system according to the following process: Preparation and status checks before system operation: a) Parameter setting: The operator inputs or retrieves the formula on the PLC touchscreen, including the type of solvent required, the target amount or final total weight, the pre-weighing values ​​of lithium salt and additives, the cycle rinsing time, the target filling weight, and the two-stage filling switching point, such as 95% and 99%. b) Status check: The PLC system self-checks that all weighing sensors are zeroed, valves are closed, nitrogen source pressure is normal, the water oxygen content in glove box 4 is below 1 ppm and the slight positive pressure is stable, and the terminal filter and pipeline are in a ready state. c) Nitrogen pre-charging: Nitrogen is continuously supplied to glove box 4 through the third branch of the nitrogen pipeline to maintain a slight positive pressure; at the same time, if the system has not been used for a long time, the first branch of the nitrogen pipeline can be opened to briefly pre-pressurize the top of each solvent tank 1.

[0048] Step 1: Nitrogen gas is introduced into the top of solvent tank 1 through the first branch of the nitrogen pipeline. The solvent is then pressurized through filter 2 and weighing tank to the intermediate pipeline, and then sent to the weighing preparation vessel 3 through the intermediate pipeline. After the solvent enters the weighing preparation vessel 3, its weighing sensor records the weight gain, while the weighing tank records the weight loss. The control system compares the two. If the difference is within the preset allowable range, such as not exceeding the reasonable estimated value of the pipeline residue, it is determined that the solvent has been basically added to the preparation vessel and there is no abnormal residue. Finally, the total amount of solvent added is precisely controlled by the weighing sensor of the weighing preparation vessel 3.

[0049] Specifically, this is manifested in the following steps: 1.1 Solvent Pressure Delivery: The PLC sequentially opens the pressure reducing valve and pneumatic ball valve of the first nitrogen branch at the top of the required solvent tank 1 according to the formula sequence. The pressure inside the tank increases, forcing the solvent out from the bottom outlet. 1.2 Filtration and Metering: The solvent enters the corresponding filter 2 through the pipeline to remove particles, and then enters the weighing and metering tank. The real-time weight signal from the weighing and metering tank is fed back to the PLC. 1.3 Feeding into the Preparation Vessel: When the amount of solvent in the weighing and metering tank reaches the formula set value, the PLC opens its outlet valve, and the solvent flows into the designated weighing and preparation vessel 3 through the intermediate pipeline. If the "cumulative metering" method is used, the solvent can also be directly pressure-delivered to the weighing and preparation vessel 3, and the final quantitative control is performed by the weighing sensor of the weighing and preparation vessel 3. 1.4 Repeated Operation: Other solvents are added sequentially according to the same steps. During the process, the weighing sensor of the weighing and preparation vessel 3 accumulates the total weight, and the PLC automatically checks whether the amount of each solvent added is within the tolerance range. If the deviation is exceeded, the system alarms and pauses.

[0050] Step 2: Manually weigh the lithium salt and / or additives inside the glove box and add them to the weighing and preparation vessel through a closed feeding pipeline.

[0051] Specifically, the operator, inside glove box 4 under a slightly positive pressure environment of high-purity nitrogen, uses a precision electronic balance to weigh the required lithium hexafluorophosphate (LiPF6) and other additives for the formula. The weighed materials are then placed into a feeding funnel and added to the weighing and preparation vessel 3 through a sealed feeding pipeline. After feeding, the valve on the feeding pipeline is closed.

[0052] Start the nitrogen pipeline. You can use an independent purging gas source or the first branch to briefly purge the feeding pipeline, such as for 2-5 seconds, to push the free droplets into the weighing and preparation vessel 3.

[0053] Step 3: Circulation washing and pre-purging: 3.1 Pre-purging: First, briefly purge the feeding pipeline through the nitrogen pipeline, such as for 2-5 seconds, to push the free droplets into the weighing and preparation vessel 3; start the circulation washing pipeline so that the material in the weighing and preparation vessel passes through the terminal filter and circulation pump, and then flows in reverse through the feeding pipeline of the glove box via the three-way valve, flushing the material remaining on the inner wall of the feeding pipeline back to the weighing and preparation vessel.

[0054] 3.2 The PLC starts the circulation pump and opens the relevant valves in the circulation flushing pipeline. This allows the mixture in the weighing and mixing vessel 3 to flow out from the bottom. At this point, the mixture already contains solvent. After passing through the terminal filter and the circulation pump, the flow direction is switched through the three-way valve, and the mixture flows in reverse through the feeding pipeline of the glove box 4, flushing off the lithium salts and additives adhering to the inner wall of the pipeline. Then, it returns to the weighing and mixing vessel 3 through the circulation return port.

[0055] 3.3. Continuous rinsing for a set time, such as 30-120 seconds, or after reaching a specified number of cycles, ensure complete recovery of residue. After completion, turn off the circulation pump and related valves.

[0056] Step 4: Start the stirrer in the weighing and mixing vessel to obtain the electrolyte.

[0057] The PLC starts the agitator inside the weighing and configuration vessel 3, and sets the speed (e.g., 200-800 rpm) and stirring time (e.g., 30-120 minutes) according to process requirements. Simultaneously, the heating / cooling jacket can be activated as needed to control the temperature inside the vessel. After stirring is complete, samples are taken to test various indicators such as moisture, acidity, and conductivity. Once qualified, the product proceeds to the filling stage.

[0058] Step 5: Fill the packaging barrel with electrolyte through the terminal filter, regulating valve and filling connector. After filling, introduce nitrogen into the filling pipeline through the second branch of the nitrogen pipeline to blow the residual electrolyte into the packaging barrel.

[0059] 5.1 Initial Filling: Place the packaging drum on the filling platform scale and connect the filling connector. The PLC opens the regulating valve and controls it to a large opening, such as 80%-100%, allowing the electrolyte to flow quickly into the packaging drum through the terminal filter, regulating valve, and filling connector. The platform scale provides real-time weight feedback.

[0060] 5.2 Two-stage precision filling: When the filling weight reaches 95% of the set target value, the PLC automatically reduces the opening of the regulating valve. If it drops to 20%-30%, the flow rate is reduced and filling continues.

[0061] When the fill rate reaches 99% or higher, such as 99.5%, further reduce the opening or intermittently open the regulating valve until the final set filling weight is reached, then close the regulating valve. 5.3 Purging Residuals: After closing the regulating valve, the PLC automatically opens the pneumatic ball valve of the second branch of the nitrogen pipeline, introducing low-pressure nitrogen (e.g., 0.1-0.3 MPa) into the filling pipeline between the regulating valve and the filling connector, blowing all residual electrolyte in the pipeline into the packaging drum, achieving "zero leakage." 5.4 Sealing and Drum Unloading: After purging, close the nitrogen valve, and the operator or automatic mechanism removes the filling connector to seal the packaging drum. Repeat the above steps if multiple drums need to be filled continuously. Example 2

[0062] like Figure 3 As shown, this embodiment is basically the same as embodiment 1, except that nitrogen is introduced into the circulating rinsing pipeline to enhance the cleaning effect on the residue on the inner wall of the feeding pipeline and to avoid crystallization blockage.

[0063] Based on Example 1, a fourth nitrogen branch line 5 is added: This branch line 5 is drawn from the main nitrogen pipe, passes through a pressure reducing valve (0.2-0.4 MPa) and a pneumatic ball valve, and then connects to the circulating rinse pipeline between the circulating pump outlet and the glove box feeding pipeline. Simultaneously, an exhaust valve and a pressure sensor are added to the top of the reactor. All other components and connections are identical to those in Example 1.

[0064] The PLC automatically selects the rinsing mode based on the weighing difference, with preset thresholds α, β, and γ, where α < β < γ. After step 1, the PLC calculates the difference Δ between the cumulative decrease in the solvent metering tank and the cumulative increase in the weighing preparation vessel. This difference reflects the residual amount in the solvent delivery pipeline. After step 2, before starting step 3, the PLC automatically selects the following rinsing mode based on the Δ value: If Δ≤α, perform normal liquid phase circulation rinsing: follow the subsequent circulation rinsing operation after the self-starting circulation pump in the original Example 1. If α<Δ≤β, perform extended liquid phase circulation rinsing: do not turn on nitrogen assistance, only extend the pure liquid phase circulation time to 30-60 seconds. If β<Δ≤γ, perform nitrogen-assisted circulation rinsing: automatically execute steps S3.3-1 to S3.3-4 below. If Δ>γ, the system alarms and stops, prompting the operator to check the solvent delivery pipeline. In this embodiment, α, β, and γ can be preset according to the system accuracy and pipeline length, for example, α=1g, β=5g, and γ=15g.

[0065] In this embodiment, the pre-purging part in step 3.1, that is, the brief purging of the feeding pipeline through the nitrogen pipeline, is performed in accordance with Example 1 regardless of the size of Δ.

[0066] When Δ>β, the following nitrogen-assisted circulating rinsing procedure replaces the original circulating rinsing operation in Example 1, that is, it replaces all operations after starting the circulating rinsing pipeline in step 3.1 of Example 1, as well as steps 3.2 and 3.3: S3.3-1: Start the circulation pump to allow the material in the preparation vessel to flow along the circulation washing pipeline for 5 seconds to wet the feeding pipeline.

[0067] S3.3-2: Open the pneumatic ball valve for 0.8 seconds to form a gas ball in the pipeline, peeling off the residue on the inner wall; close the pneumatic ball valve, and continue circulating the pure liquid phase for 10 seconds to carry the peeled material back to the preparation vessel. Repeat the above nitrogen pulse-liquid phase flushing 5 times.

[0068] S3.3-3: Recirculate the pure liquid phase for 10 seconds to make the material uniform.

[0069] S3.3-4: Stop the circulation pump, open the exhaust valve, and then continuously purge with nitrogen for 3 minutes to thoroughly dry the residual liquid film in the feed line and prevent crystallization. After drying, close the pneumatic control ball valve and the exhaust valve.

[0070] Example 2 provides a nitrogen-assisted circulation cleaning method based on weighing difference adaptive. The residual amount Δ of the solvent pipeline is calculated by comparing two weighing values, and the normal liquid phase circulation, extended liquid phase circulation or nitrogen-assisted pulse drying mode is automatically selected by using preset thresholds α, β and γ. In this way, the energy consumption and time are optimized according to the actual cleanliness of the solvent pipeline while ensuring that the feeding pipeline is effectively cleaned after each feeding.

[0071] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the implementation of the present invention is not limited to the above-described manner. Any improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. An automatic electrolyte mixing system, characterized in that, include: Multiple solvent metering units are provided. Each solvent metering unit consists of a solvent tank (1), a filter (2) and a weighing metering tank connected in series. The outlet of the solvent tank (1) is connected to the inlet of the filter (2) through a pipeline. The outlet of the filter (2) is connected to the inlet of the weighing metering tank through a pipeline. The outlet of the weighing metering tank is connected to an intermediate pipeline through a pipeline. At least one mixing and filling module, each mixing and filling module is composed of a weighing and configuration vessel (3), a terminal filter, a regulating valve and a filling connector connected in series. The bottom outlet of the weighing and configuration vessel (3) is connected to the inlet of the terminal filter, the outlet of the terminal filter is connected to the inlet of the regulating valve, and the outlet of the regulating valve is connected to the filling connector. The outlets of the plurality of solvent metering units are connected in parallel to the inlet of the at least one mixing and filling module via the intermediate pipeline. The glove box (4) is connected to the top inlet of one or more of the weighing and configuration vessels (3) via a sealed feeding pipeline; The circulating rinsing pipeline includes a circulating pump and connecting pipelines. The inlet of the circulating pump is connected to the outlet of the terminal filter. The outlet of the circulating pump is connected to the top circulation return port of the weighing and configuration vessel (3) through a pipeline. A tee is provided on the pipeline between the outlet of the circulating pump and the top of the weighing and configuration vessel. The tee is connected to the feeding pipeline of the glove box (4) to form a return loop in which the material flows in reverse through the feeding pipeline. The nitrogen pipeline has three branches: the first branch is connected to the top of each solvent tank (1) for pressurizing the solvent; the second branch is connected to the filling pipeline between each regulating valve and the corresponding filling connector for purging residual electrolyte; and the third branch is connected to the gas replenishment port of the glove box (4) for maintaining a slightly positive pressure nitrogen atmosphere in the glove box.

2. The automatic electrolyte mixing system according to claim 1, characterized in that: There are multiple weighing and configuration vessels (3), and multiple mixing and filling modules are connected in parallel. The outlets of the multiple solvent metering units are connected to the inlets of the multiple mixing and filling modules through the intermediate pipeline.

3. The automatic electrolyte mixing system according to claim 1, characterized in that: The terminal filter serves as both a dynamic filter during cyclic rinsing and a final filter before filling.

4. The automatic electrolyte mixing system according to claim 1, characterized in that: The glove box (4) is a slightly positive pressure nitrogen protection box, which is equipped with a precision electronic balance and a feeding funnel. The water and oxygen content inside is controlled to be below 1 ppm.

5. The automatic electrolyte mixing system according to claim 1, characterized in that: The first branch of the nitrogen pipeline is equipped with a pressure reducing valve and a pneumatic ball valve, the second branch is equipped with a pressure reducing valve and a pneumatic ball valve, and the third branch is equipped with a pressure reducing valve and a ball valve.

6. The automatic electrolyte mixing system according to claim 1, characterized in that: It also includes a fourth nitrogen branch (5), which is led out from the nitrogen main pipe, and connected to the circulating washing pipeline between the outlet of the circulating pump and the glove box feeding pipeline after passing through the pressure reducing valve and the air control ball valve; the top of the weighing and configuration vessel (3) is also equipped with an exhaust valve and a pressure sensor.

7. An automatic mixing method using the automatic electrolyte mixing system according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Nitrogen gas is introduced into the top of the solvent tank (1) through the first branch of the nitrogen pipeline. The solvent is then pressurized through the filter (2) and the weighing metering tank to the intermediate pipeline, and then sent into the weighing preparation vessel (3) through the intermediate pipeline. After the solvent enters the weighing preparation vessel (3), it is re-weighed by its weighing sensor. The re-weighed value is compared with the measurement value of the weighing metering tank to confirm that all the solvent in the pipeline has been added to the preparation vessel. Finally, the total amount of solvent added is precisely controlled by the weighing sensor of the weighing preparation vessel. Step 2: Manually weigh lithium salt and / or additives in the glove box (4) and add them to the weighing and preparation vessel (3) through a closed feeding pipeline. Step 3: Start the circulating flushing pipeline so that the material in the weighing and preparation vessel (3) flows through the terminal filter and the circulating pump, and then flows in reverse through the feeding pipeline of the glove box (4) via the three-way valve, flushing the material remaining on the inner wall of the feeding pipeline back to the weighing and preparation vessel (3). Step 4: Start the stirrer of the weighing and preparation vessel (3) to mix and obtain the electrolyte; Step 5: Fill the packaging barrel with electrolyte through the terminal filter, regulating valve and filling connector. After filling, introduce nitrogen into the filling pipeline through the second branch of the nitrogen pipeline to blow the residual electrolyte into the packaging barrel.

8. The automatic mixing method according to claim 7, characterized in that: In step 3, before starting the circulating rinsing pipeline, the feeding pipeline is briefly purged through the nitrogen pipeline to push the free droplets into the weighing and preparation vessel (3).

9. The automatic mixing method according to claim 7, characterized in that: In step 5, the filling process adopts a two-stage control: first, filling at the maximum flow rate to 95% of the set capacity, then reducing the flow rate to fill to over 99%, and finally purging the residue with nitrogen.

10. The automatic mixing method according to claim 7, characterized in that: In steps 1 and 2, the weighing sensor of the weighing configuration vessel (3) accumulates the total weight, and the control system automatically verifies the integrity of the feeding.

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