Liquid injection device and method for improving liquid injection accuracy

Abstract

The application provides a liquid injection device and a method for improving liquid injection precision, and relates to the field of lithium batteries. A metering tank is placed in a liquid storage tank, and a to-be-injected liquid is introduced into the liquid storage tank to a liquid discharge port; a bottom of the metering tank is adhered to a bottom wall of the liquid storage tank by applying pressure to the metering tank, a cover plate and a filling rod are pressed down, the liquid in the metering tank is overflowed from a top opening in the process of pressing down, and the cover plate is adhered to a top wall of the metering tank; at this time, the metering tank contains a specific amount of the to-be-injected liquid, and the volume V of the to-be-injected liquid in the metering tank is only related to the volume V1 of the metering tank, the volume V2 of the filling rod and the like, and the machining level of the components can guarantee the high liquid injection precision; the volume V in the metering tank is irrelevant to the delivery precision of a pump, and a conventional centrifugal pump can be selected, and one pump can drive multiple metering tanks and liquid injection cups at the same time, and the cost is lower.

Description

Technical Field

[0001] This invention relates to the field of lithium batteries, and more specifically, to a liquid injection device and a method for improving liquid injection accuracy. Background Technology

[0002] In the lithium battery production process, an essential electrolyte injection step is required. To ensure injection accuracy, a high-precision plunger pump is typically used to pump the electrolyte from the storage tank to the injection cup, and then inject the electrolyte from the injection cup into the battery. To guarantee the injection accuracy, a high-precision plunger pump is usually used to control the electrolyte flow rate. However, this method presents the following main problems:

[0003] ① Conventionally, one plunger pump controls the weight of electrolyte in 1-2 injection cups. The more pumps there are, the lower the accuracy. Currently, the conventional injection equipment has 8 stations (i.e., 8 injection cups), which requires at least 4 plunger pumps. However, plunger pumps are very expensive (at least 100,000 RMB each).

[0004] ② Taking the commonly used 280AH battery cell on the market as an example, the electrolyte injection volume is 800-1200g, and the injection accuracy of the plunger pump can only reach ±10g, which cannot further improve the accuracy.

[0005] Therefore, this application is submitted. Summary of the Invention

[0006] The purpose of this invention is to provide a liquid injection device and a method for improving liquid injection accuracy, aiming to improve liquid injection accuracy while reducing costs.

[0007] The embodiments of the present invention can be implemented as follows:

[0008] In a first aspect, the present invention provides a liquid injection device, including a liquid storage tank and at least one metering tank, wherein the liquid storage tank is provided with a liquid inlet and a liquid outlet, and the top and bottom of the metering tank are both open; at least one injection pipe for discharging liquid from the metering tank is connected to the bottom wall of the liquid storage tank.

[0009] Let H1 be the distance between the bottom of the drain port of the liquid storage tank and the bottom wall of the liquid storage tank, and let H2 be the height of the metering tank, and satisfy H1 < H2; the metering tank can be placed in the liquid storage tank and generate relative movement, so that the bottom of the metering tank is away from or attached to the bottom inner wall of the liquid storage tank.

[0010] It also includes a cover assembly for closing the top of the metering tank before liquid discharge. The cover assembly includes a cover plate and at least one filling rod for expelling gas from the top of the metering tank when closed. The cover plate has a first end face for abutting the top of the metering tank and a second end face opposite to the first end face. Each filling rod extends from the first end face of the cover plate. An air inlet pipe extending to the first end face is also installed on the cover plate. The air inlet pipe is an openable and closable pipe so that after the filling rod extends into the top of the metering tank and the cover plate is abutting the top wall of the metering tank, the liquid in the metering tank is discharged from the injection pipe by air intake from the air inlet pipe.

[0011] In an optional embodiment, a volume adjustment rod is also connected to the cover plate, one end of which extends from the first end face of the cover plate, and the length of the volume adjustment rod extending from the first end face is less than the length of the filling rod extending from the first end face.

[0012] In an optional implementation, the volume adjustment rod is movably connected to the cover plate to adjust the length of the volume adjustment rod extending from the first end face of the cover plate.

[0013] In an optional embodiment, the liquid injection device further includes a drive component for driving the cover plate to rise and fall, a fixing block is connected to the second end face of the cover plate, the other end of the volume fine adjustment rod extends from the fixing block, the air inlet pipe extends from the end of the fixing block away from the second end face of the cover plate to the second end face, and an air pipe connector is also provided at the end of the fixing block away from the second end face of the cover plate.

[0014] In an optional embodiment, the device further includes a fixing frame for fixing the metering tank and a drive component for driving the fixing frame to rise and fall. The fixing frame includes a top crossbeam, a bottom connecting rod, and two end support rods. The bottom connecting rod includes two end connecting rods and at least one intermediate connecting rod. The two ends of the intermediate connecting rod are respectively connected to the side walls of two adjacent metering tanks. One end of each end connecting rod is connected to the side wall of the metering tank located at the end, and the other end is connected to the bottom of an end support rod. The top of each end support rod is connected to the top crossbeam.

[0015] In an optional embodiment, the distance between the center of the drain port of the liquid storage tank and the bottom wall of the liquid storage tank is H0, and H1 < H2 < H0.

[0016] In an optional implementation, the inner diameter of the top of the metering tank is smaller than the inner diameter of the bottom.

[0017] In an optional embodiment, a sealing groove is provided on the bottom inner wall of the storage tank, which matches the bottom diameter of the metering tank, and a sealing gasket is installed on the sealing groove.

[0018] In an optional embodiment, the system further includes a storage tank and a transfer pump, with the inlet end of the transfer pump connected to the storage tank and the outlet end of the transfer pump connected to the inlet on the storage tank.

[0019] Each injection tube is equipped with a switch valve, and the outlet end of each injection tube is connected to an injection cup.

[0020] Secondly, the present invention provides a method for improving injection accuracy, which utilizes the injection device of any of the foregoing embodiments for injection, comprising:

[0021] Place the metering tank into the storage tank and pass the liquid to be injected into the storage tank until it reaches the drain port;

[0022] By applying pressure to the metering tank, the bottom of the metering tank is pressed against the bottom wall of the storage tank, causing the cover plate and filling rod to be pressed down. During the pressing process, the liquid in the metering tank overflows from the top opening, causing the cover plate to be pressed against the top wall of the metering tank.

[0023] Air is introduced through the air inlet pipe, causing the liquid to be injected in the metering tank to be discharged through the injection pipe;

[0024] Preferably, the liquid to be injected is an electrolyte.

[0025] The beneficial effects of this invention are as follows: In use, the metering tank is placed in the storage tank, and the liquid to be injected is introduced into the storage tank until the drain port is reached. By applying pressure to the metering tank, the bottom of the metering tank is made to adhere to the bottom wall of the storage tank, causing the cover plate and filling rod to press down. During the pressing process, the liquid in the metering tank overflows from the top opening, causing the cover plate to adhere to the top wall of the metering tank. At this time, the metering tank contains a specific volume of liquid to be injected. Moreover, the volume V of the liquid to be injected in the metering tank is only related to the volume V1 of the metering tank, the volume V2 of the filling rod, etc., and these components can be guaranteed by the processing level of the parts, resulting in high injection accuracy. The volume V in the metering tank is independent of the pump's delivery accuracy, so a conventional centrifugal pump can be used. Furthermore, one pump can drive multiple metering tanks and injection cups simultaneously, resulting in lower cost. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the liquid injection device provided by the present invention;

[0028] Figure 2 for Figure 1 Schematic diagram of the structure of the intermediate liquid storage tank;

[0029] Figure 3 for Figure 1 Schematic diagram of the metering tank;

[0030] Figure 4 for Figure 1 Enlarged view of region IV;

[0031] Figure 5 This is a diagram showing the first operating state of the liquid injection device;

[0032] Figure 6 This is a diagram showing the second operating state of the liquid injection device;

[0033] Figure 7 This is a diagram showing the third working state of the liquid injection device;

[0034] Figure 8 This is a diagram showing the fourth operating state of the liquid injection device.

[0035] Icons: 100-Injection device; 110-Storage tank; 111-Inlet; 112-Outlet; 113-Sealing groove; 120-Metering tank; 130-Injection pipe; 131-Second switch valve; 140-Cover assembly; 141-Cover plate; 1411-First end face; 1412-Second end face; 142-Filling rod; 143-Air inlet pipe; 144-First switch valve; 145-Volume fine-tuning rod; 146-Fixing block; 147-Air pipe connector; 150-Fixing frame; 151-Top crossbeam; 152-Bottom connecting rod; 1521-End connecting rod; 1522-Intermediate connecting rod; 153-End support rod; 160-Storage pool; 170-Transfer pump; 180-Injection cup. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0038] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0039] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0040] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0041] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0042] Please refer to Figure 1 This embodiment provides a liquid injection device 100, including a liquid storage tank 160, a transfer pump 170, a liquid storage tank 110, at least one metering tank 120, an injection pipe 130, and an injection cup 180. Liquid in the liquid storage tank 160 is pumped to the liquid storage tank 110 by the transfer pump 170. A specific volume of liquid is measured by the metering tank 120 and then transported through the injection pipe 130 to the injection cup 180, thereby injecting a specific volume of liquid into the injection cup 180.

[0043] It should be added that the injection volume of the liquid to be injected is not related to the pump's delivery accuracy, so a conventional centrifugal pump can be used. Furthermore, one pump can drive multiple metering tanks 120 and injection cups 180 simultaneously, resulting in lower costs.

[0044] The storage tank 160 can be any container capable of storing the liquid to be injected, and is not limited to tanks, pools, or other structures; it can be selected as needed. The transfer pump 170 can be, but is not limited to, a regular water pump, and the type of liquid to be injected can be, but is not limited to, electrolyte. The inlet of the transfer pump 170 is connected to the storage tank 160, and the outlet of the transfer pump 170 is connected to the inlet 111 on the storage tank 110.

[0045] Please combine Figure 1 and Figure 2The storage tank 110 is provided with an inlet 111 and a outlet 112. Liquid is input through the inlet 111 and discharged through the outlet 112. Therefore, the outlet 112 is located above the horizontal position of the inlet 111. A sealing groove 113 is provided on the inner bottom wall of the storage tank 110, which matches the bottom diameter of the metering tank 120. A sealing gasket (not shown) is installed on the sealing groove 113. The metering tank 120 can be accommodated in the storage tank 110 and undergo relative movement, so that the bottom of the metering tank 120 moves away from or against the inner bottom wall of the storage tank 110. When the metering tank 120 is against the storage tank 110, it is confined within the sealing groove 113, and the sealing gasket provides a good seal, preventing liquid from overflowing from the bottom.

[0046] In some embodiments, the inlet 111 of the liquid storage tank 110 is located on the bottom wall, and the outlet 112 of the liquid storage tank 110 is located on the top side wall. The number of outlets 112 is not limited and can be two opposite to each other, but is not limited thereto. The top of the liquid storage tank 110 can be open or have a cover, which is not limited here.

[0047] The bottom wall of the storage tank 110 is connected to at least one injection pipe 130 for discharging liquid from the metering tank 120. The number of metering tanks 120 corresponds to the number of injection pipes 130, with each metering tank 120 corresponding to one injection pipe 130. The end of each injection pipe 130 is connected to an injection cup 180. In other embodiments, each metering tank 120 may correspond to two or more injection pipes 130 to improve injection efficiency.

[0048] Please refer to Figure 1 and Figure 3 The metering tank 120 has openings at both the top and bottom, and the inner diameter of the top of the metering tank 120 is smaller than the inner diameter of the bottom. Let H1 be the distance between the bottom end of the drain port 112 of the storage tank 110 and the bottom wall of the storage tank 110, and let H2 be the height of the metering tank 120, satisfying H1 < H2. After the storage tank 110 is filled with liquid, the liquid can be discharged from the drain port 112; at this time, the metering tank 120 is not yet full.

[0049] Specifically, the metering tank 120 can be roughly divided into three sections: a top constriction section, a diameter reduction section, and a bottom wide opening section. The bottom wide opening section has a large enough opening to facilitate the rapid filling of the metering tank 120 with electrolyte during the metering process. The top constriction section should be small enough so that the liquid level can rise rapidly when air is discharged from the top pipe opening, making it easier for the liquid level to quickly reach the pipe opening.

[0050] In some embodiments, the distance between the center of the drain port 112 of the storage tank 110 and the bottom wall of the storage tank 110 is H0 (not shown in the figure), and satisfies H1 < H2 < H0. That is, the height of the metering tank 120 is H2, which is only slightly greater than H1, so that the metering tank 120 is also in a state of near fullness after the storage tank 110 is filled with liquid.

[0051] Please refer to Figure 1 and Figure 4 The liquid injection device 100 also includes a cover assembly 140 for covering the top of the metering tank 120 before liquid discharge. The cover assembly 140 includes a cover plate 141 and at least one filling rod 142 for expelling gas from the top of the metering tank 120 when the cover is closed. Each metering tank 120 may correspond to one filling rod 142, but is not limited to this one-to-one correspondence. The cover plate 141 has a first end face 1411 for abutting against the top of the metering tank 120 and a second end face 1412 opposite to the first end face 1411. Each filling rod 142 extends from the first end face 1411 of the cover plate 141. An air inlet pipe 143 extending to the first end face 1411 is also installed on the cover plate 141. The air inlet pipe 143 is an openable and closable pipe so that after the filling rod 142 extends into the top of the metering tank 120 and the cover plate 141 abuts against the top wall of the metering tank 120, the liquid in the metering tank 120 is discharged from the injection pipe 130 by air intake from the air inlet pipe 143.

[0052] Specifically, a first switching valve 144 is provided on the air inlet pipe 143. The first switching valve 144 is closed before air is supplied and opens when air is supplied, so as to discharge the liquid in the metering tank 120.

[0053] The cover assembly 140 may include a cover plate 141, or each metering tank 120 may have a corresponding cover plate 141; this is not limited here. Using a cover plate 141 with multiple filling rods 142 installed facilitates standardized operation. The first switching valve 144 may be, but is not limited to, a typical one-way valve.

[0054] In some embodiments, a volume adjustment rod 145 is also connected to the cover plate 141. One end of the volume adjustment rod 145 extends from the first end face 1411 of the cover plate 141, and the length of the volume adjustment rod 145 extending from the first end face 1411 is less than the length of the filling rod 142 extending from the first end face 1411. The volume adjustment rod 145 can be used for further fine-tuning, and it can be integrally set with the filling rod 142 or set separately.

[0055] In some embodiments, the volume adjustment rod 145 is movably connected to the cover plate 141 to adjust the length of the volume adjustment rod 145 extending from the first end face 1411 of the cover plate 141. The method of movable connection is not limited; for example, it can be a threaded connection or an electrically controlled connection. An electrically controlled connection could involve driving the volume adjustment rod 145 up and down via an external cylinder, but is not limited to this. By controlling the up and down movement of the volume adjustment rod 145, the length of the volume adjustment rod 145 extending from the first end face 1411 of the cover plate 141 can be adjusted, ultimately regulating the volume of the liquid in the metering tank 120.

[0056] In some embodiments, a fixing block 146 is also connected to the second end face 1412 of the cover plate 141. The other end of the volume fine-tuning rod 145 extends from the fixing block 146. An air inlet pipe 143 extends from one end of the fixing block 146 away from the second end face 1412 of the cover plate 141 to the second end face 1412. An air pipe connector 147 is also provided at one end of the fixing block 146 away from the second end face 1412 of the cover plate 141. The air pipe connector 147 is used to communicate with an external compressed air supply pipe to introduce compressed air and discharge the liquid in the metering tank 120 by applying pressure.

[0057] In some embodiments, for the purpose of facilitating unified operation and control, the liquid injection device 100 further includes a fixing frame 150 for fixing the metering tank 120 and a driving component (not shown) for driving the fixing frame 150 to rise and fall. The fixing frame 150 includes a top crossbeam 151, a bottom connecting rod 152 and two end support rods 153. The bottom connecting rod 152 includes two end connecting rods 1521 and at least one intermediate connecting rod 1522. The two ends of the intermediate connecting rod 1522 are respectively connected to the side walls of two adjacent metering tanks 120. One end of each end connecting rod 1521 is connected to the side wall of the metering tank 120 located at the end, and the other end of each end connecting rod 1521 is connected to the bottom of an end support rod 153. The top of each end support rod 153 is connected to the top crossbeam 151. By uniformly controlling the height of the top beam 151, the position of each metering tank 120 can be controlled. After the liquid storage tank 110 is filled with liquid, pressure can be applied to the top beam 151 through external cylinders or other equipment, so that each metering tank 120 is attached to the bottom wall of the liquid storage tank 110. Each metering tank 120 corresponds to the injection pipe 130, which facilitates subsequent liquid drainage operations.

[0058] Specifically, the driving components for raising and lowering the cover plate 141 and the driving components for raising and lowering the fixed frame 150 can both be cylinders. The fixed frame 150 and the cover plate 141 can be connected to external cylinders respectively, so that the external cylinders can provide pressure or lifting force to the fixed frame 150 to control the raising and lowering of the fixed frame 150, thereby controlling the raising and lowering of the metering tank 120; and the external cylinders can provide pressure or lifting force to the cover plate 141 to control the raising and lowering of the cover plate 141. The fixed frame 150 and the cover plate 141 can be different external cylinders, and the type of cylinder is not limited.

[0059] In some embodiments, a second switching valve 131 is provided on each injection pipe 130, and the outlet end of each injection pipe 130 is connected to an injection cup 180. After compressed air is introduced, the first switching valve 144 and the second switching valve 131 are opened simultaneously, discharging the liquid in the metering tank 120 from the injection pipe 130 to the injection cup 180. Specifically, the number of injection cups 180 can also correspond to the number of metering tanks 120, that is, one metering tank 120 corresponds to one injection pipe 130 and one injection cup 180. However, it is not limited to the above correspondence; one metering tank 120 can correspond to two or more injection pipes 130, or it can correspond to two or more injection cups 180.

[0060] In some embodiments, a one-way valve may also be provided on the injection pipe 130, as shown in the figure, located above the second switching valve 131 and in contact with the storage tank 110.

[0061] It should be noted that the liquid storage tank 160 and the liquid injection cup 180 may not be included in the complete set of equipment, but may be adjusted according to the source of the liquid to be injected and the target container.

[0062] This invention also provides a method for improving injection accuracy, which utilizes the above-mentioned injection device 100 for injection, including:

[0063] S1, Liquid storage tank 110 filled with liquid

[0064] Please refer to Figure 1 and Figure 5 Place the metering tank 120 in the liquid storage tank 110, and introduce the liquid to be injected into the liquid storage tank 110 until the drain port 112 is reached.

[0065] By starting the transfer pump 170, the liquid in the storage tank 160 is transferred to the storage tank 110. The liquid level in the storage tank 110 gradually rises. When the liquid level reaches H1, the excess liquid flows out from the drain port 112. The transfer pump 170 operates continuously, and the liquid level in the storage tank 110 is always maintained at height H1. At this time, the liquid level in the metering tank is H1-H3, and the distance from the liquid level in the metering tank to the metering tank opening is H2+H3-H1.

[0066] S2, Downward Exhaust

[0067] Please refer to Figures 4-7 By applying pressure to the metering tank 120, the bottom of the metering tank 120 is made to adhere to the bottom wall of the liquid storage tank 110, and the cover plate 141 and the filling rod 142 are pressed down. During the pressing process, the liquid in the metering tank 120 overflows from the top opening, and the cover plate 141 adheres to the top wall of the metering tank 120.

[0068] Specifically, using an external cylinder or other driving component, the metering tank 120 and the cover plate 141 are lowered together by a stroke of H3. At this point, the bottom of the metering tank 120 is in contact with the bottom of the storage tank 110, the liquid level in the metering tank 120 is H1, and the distance from the liquid level in the metering tank to the metering tank inlet is H2-H1. After the bottom of the metering tank is in contact with the tank body, the disturbance of the fluid inside the tank causes the water pump to continuously pump the liquid to be injected, such as electrolyte, into the tank, while the electrolyte is continuously discharged from the drain port, without affecting the liquid in the metering tank.

[0069] like Figure 7 As shown, the cover plate above the metering tank 120 is pressed down to a stroke H4, at which point the cover plate is flush with the top opening of the metering tank. During the pressing process, the filling rod 142 is continuously inserted into the metering tank, causing the liquid level in the metering tank 120 to rise continuously to the opening of the metering tank 120. At this point, the metering tank 120 is completely filled with liquid, the filling rod 142, and the volume adjustment rod 145, and excess liquid flows out from the opening. At this time, the liquid level in the metering tank is H2, and the volume V in the metering tank is equal to the volume of the metering tank V1 - the volume of the filling rod 142 V2 - the volume of the filling rod 142 V3. In this process, the function of the filling rod 142 is to ensure that the electrolyte level is flush with the opening; the function of the volume adjustment rod 145 is to change the insertion depth of the volume adjustment rod 145, thereby fine-tuning the volume of the electrolyte in the metering tank.

[0070] S3. Drainage

[0071] Air is introduced through the air inlet pipe 143, and the first switch valve 144 is opened, allowing the liquid to be injected in the metering tank 120 to be discharged through the injection pipe 130. Air can be introduced by opening the air inlet pipe 143, or compressed gas can be introduced through the air inlet pipe 143 to accelerate the outflow of liquid from the metering tank 120.

[0072] In actual operation, the air pipe connector 147 can be connected to an external compressed air pipeline, and the first switch valve 144 and the second switch valve 131 can be opened simultaneously. Under the action of compressed air, all the liquid in the metering tank is discharged into the filling cup 180. At this time, the liquid volume in the metering tank is 0, and the liquid volume in the filling cup 180 is V. Figure 8 As shown.

[0073] It should be added that after the drainage is completed, the first switch valve 144 and the second switch valve 131 are closed, the air in the air inlet pipe 143 is shut off, and the next injection cycle is repeated.

[0074] The entire working process demonstrates that the liquid volume V in the injection cup 180 is only related to the volume V1 of the metering tank 120, the volume V2 of the filling rod 142, and the volume V3 of the volume fine-tuning rod 145. The injection accuracy of these components can be guaranteed solely by the manufacturing level of their parts. The volume V in the injection cup 180 is independent of the pump's delivery accuracy; a conventional centrifugal pump can be used. Furthermore, one pump can simultaneously drive multiple metering tanks 120 and injection cups 180, resulting in lower costs.

[0075] In summary, the embodiments of the present invention provide a liquid injection device and a method for improving liquid injection accuracy. By improving the way of injecting liquid into the injection cup, after the liquid storage tank is filled with liquid, the liquid in the metering tank can be filled by using structures such as a metering tank, a cover plate, and a filling rod. The liquid volume V in the metering tank is only related to the volume V1 of the metering tank, the volume V2 of the filling rod, and the volume fine-tuning rod V3, and is not related to the pump's delivery accuracy. A conventional centrifugal pump can be used, which can improve the liquid injection accuracy while reducing the liquid injection cost.

[0076] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A liquid injection device, characterized in that, The device includes a storage tank and at least one metering tank. The storage tank is provided with an inlet and a outlet. The outlet is located above the horizontal position of the inlet. The metering tank is open at both the top and bottom. At least one injection pipe for discharging liquid from the metering tank is connected to the bottom wall of the storage tank. Let H1 be the distance between the bottom end of the drain port of the liquid storage tank and the bottom wall of the liquid storage tank, and let H2 be the height of the metering tank, and satisfy H1 < H2; the metering tank can be accommodated in the liquid storage tank and generate relative movement, so that the bottom of the metering tank is away from or attached to the bottom inner wall of the liquid storage tank. It also includes a cover assembly for closing the top of the metering tank before liquid discharge. The cover assembly includes a cover plate and at least one filling rod for expelling gas from the top of the metering tank when closed. The cover plate has a first end face for abutting the top of the metering tank and a second end face opposite to the first end face. Each of the filling rods extends from the first end face of the cover plate. The cover plate is also equipped with an air inlet pipe extending to the first end face. The air inlet pipe is an openable and closable pipe so that after the filling rod extends into the top of the metering tank and the cover plate abuts the top wall of the metering tank, the liquid in the metering tank is discharged from the injection pipe by air intake from the air inlet pipe. The cover plate is also connected to a volume adjustment rod, one end of which extends from the first end face of the cover plate, and the length of the volume adjustment rod extending from the first end face is less than the length of the filling rod extending from the first end face.

2. The liquid injection device according to claim 1, characterized in that, The volume adjustment rod is movably connected to the cover plate to adjust the length of the volume adjustment rod extending from the first end face of the cover plate.

3. The liquid injection device according to claim 2, characterized in that, The liquid injection device also includes a driving component for driving the cover plate to rise and fall. A fixing block is also connected to the second end face of the cover plate. The other end of the volume fine adjustment rod extends from the fixing block. The air inlet pipe extends from the end of the fixing block away from the second end face of the cover plate to the second end face. An air pipe connector is also provided at the end of the fixing block away from the second end face of the cover plate.

4. The liquid injection device according to claim 1, characterized in that, It also includes a fixing frame for fixing the metering tank and a driving component for driving the fixing frame to rise and fall. The fixing frame includes a top crossbeam, a bottom connecting rod and two end support rods. The bottom connecting rod includes two end connecting rods and at least one intermediate connecting rod. The two ends of the intermediate connecting rod are respectively connected to the side walls of two adjacent metering tanks. One end of each end connecting rod is connected to the side wall of the metering tank located at the end. The other end of each end connecting rod is connected to the bottom of one of the end support rods. The top of each end support rod is connected to the top crossbeam.

5. The liquid injection device according to claim 1, characterized in that, The distance between the center of the drain port of the liquid storage tank and the bottom wall of the liquid storage tank is H0, and H1 < H2 < H0.

6. The liquid injection device according to claim 1, characterized in that, The inner diameter of the top of the metering tank is smaller than the inner diameter of the bottom.

7. The liquid injection device according to claim 1, characterized in that, The bottom inner wall of the liquid storage tank is provided with a sealing groove that matches the bottom diameter of the metering tank, and a sealing gasket is installed on the sealing groove.

8. The liquid injection device according to claim 1, characterized in that, It also includes a storage tank and a transfer pump, wherein the inlet end of the transfer pump is connected to the storage tank and the outlet end of the transfer pump is connected to the inlet on the storage tank. Each of the injection tubes is equipped with a switch valve, and the outlet end of each injection tube is connected to an injection cup.

9. A method for improving injection accuracy, characterized in that, It uses the injection device according to any one of claims 1-8 to perform injection, comprising: Place the metering tank in the liquid storage tank, and introduce the liquid to be injected into the liquid storage tank until the drain port is reached; By applying pressure to the metering tank, the bottom of the metering tank is made to adhere to the bottom wall of the liquid storage tank, and the cover plate and the filling rod are pressed down. During the pressing process, the liquid in the metering tank overflows from the top opening, and the cover plate adheres to the top wall of the metering tank. Air is introduced through the air inlet pipe, causing the liquid to be injected in the metering tank to be discharged through the injection pipe.

10. The method according to claim 9, characterized in that, The liquid to be injected is an electrolyte.

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