Liquid injection device, battery cell cover plate, battery and electric equipment
By using a liquid injection device with a parallel connection of an injection needle and a vacuum needle, a vacuum pump extracts the gas inside the battery cell to create a negative pressure environment, which solves the problems of low liquid injection efficiency and high cost, and achieves efficient liquid injection and low-cost production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 广东瑞浦兰钧能源有限公司
- Filing Date
- 2025-04-29
- Publication Date
- 2026-04-24
AI Technical Summary
Existing technologies suffer from low electrolyte injection efficiency, high production costs, and the tendency for electrolyte to overflow, leading to defective products and contamination.
A liquid injection device with a parallel connection of injection needle and suction needle is used. The vacuum pump extracts the gas inside the battery cell through the suction needle to form a negative pressure environment and maintain the internal gas pressure balance of the battery cell.
Improve electrolyte injection efficiency, reduce defective products, lower production costs, and avoid electrolyte overflow and contamination.
Smart Images
Figure CN224164376U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of battery technology, and specifically relates to a liquid injection device, a battery cell cover, a battery, and electrical equipment. Background Technology
[0002] In the manufacturing process of aluminum-cased battery cells, automated electrolyte injection is a crucial step. As the core component of the battery, the effectiveness of electrolyte injection directly affects the cell's performance, safety, and lifespan. Currently, the commonly used injection method is single-needle injection. This method injects electrolyte into the cell under high pressure. However, at the moment the injection needle is withdrawn, the internal pressure of the cell is much higher than the external air pressure, making electrolyte prone to overflow. This overflow not only corrodes the explosion-proof valve protective film on the cell's top cover, leading to material loss, but also severely contaminates the cell's appearance, resulting in a large number of defective products, high production costs, and low injection efficiency.
[0003] Therefore, it is necessary to provide a new technical solution to solve the above-mentioned technical problems. Utility Model Content
[0004] The technical problem to be solved by this utility model is the low injection efficiency and high production cost.
[0005] To solve the above-mentioned technical problems, this utility model provides a liquid injection device, which includes a sealing element with an inlet hole and an outlet hole, an injection needle for injecting electrolyte into the battery cell, a suction needle arranged in parallel with the injection needle, and a vacuum pump. The injection needle passes through the inlet hole, the suction needle passes through the outlet hole, and the length of the suction needle protruding into the battery cell is less than the length of the injection needle protruding into the battery cell. The vacuum pump is connected to the suction needle through a suction pipe. During the liquid injection process, the vacuum pump extracts gas from inside the battery cell through the suction needle.
[0006] Optionally, the length of the suction needle probing into the battery cell is one-quarter to three-quarters of the length of the injection needle probing into the battery cell.
[0007] Optionally, the liquid injection device further includes an automatic control valve and a pressure sensor. The automatic control valve is disposed on the suction needle and is located between the seal and the vacuum pump. The pressure sensor is disposed on the suction needle and is located between the automatic control valve and the seal. The pressure sensor is connected to the automatic control valve.
[0008] Optionally, the automatic control valve includes a valve and a controller connected to the valve and the pressure sensor respectively. The valve is disposed on the suction needle and is located between the automatic control valve and the seal. The pressure sensor is used to collect the internal pressure of the battery cell in real time. The controller receives the internal pressure of the battery cell collected by the pressure sensor and compares the pressure with a first set threshold. When the pressure is greater than the first set threshold, the controller triggers the vacuum pump to work and the valve opens.
[0009] Optionally, the numerical range of the first set threshold is 10%*P±0.5Pa, where P is standard atmospheric pressure.
[0010] Optionally, the controller compares the air pressure with a second set threshold. When the air pressure is less than the second set threshold, the controller triggers the vacuum pump to stop and the valve to close.
[0011] Optionally, the numerical range of the second set threshold is 5%*P±0.5Pa, where P is standard atmospheric pressure.
[0012] According to another aspect of the present invention, the present invention also provides a battery cell cover plate, including a cell cover plate and an injection device disposed on the cell cover plate as described above.
[0013] According to another aspect of the present invention, the present invention also provides a battery, including the aforementioned battery cell cover plate.
[0014] According to another aspect of the present invention, the present invention also provides an electrical device, including the battery described above, the battery being used to provide electrical energy.
[0015] Beneficial effects:
[0016] This invention provides a liquid injection device. A liquid injection needle penetrates an inlet hole located in a sealing element to inject electrolyte into the battery cell. A vacuum needle penetrates an vent hole located in the sealing element. The vacuum needle and the liquid injection needle are connected in parallel. The length of the vacuum needle penetrating into the battery cell is less than the length of the liquid injection needle penetrating into the battery cell. A vacuum pump is connected to the vacuum needle through a vacuum pipe. During the liquid injection process, the vacuum pump extracts gas from inside the battery cell through the vacuum needle. Thus, during the liquid injection process, the liquid injection needle injects electrolyte into the battery cell, causing the internal gas pressure to rise. To maintain the internal gas pressure balance of the battery cell and prevent electrolyte overflow, the vacuum system composed of the vacuum needle and the vacuum pump promptly extracts gas from inside the battery cell, creating a negative pressure environment. A negative pressure environment not only promotes rapid electrolyte penetration and reduces injection time, but also effectively prevents electrolyte from overflowing when the injection needle is withdrawn due to internal pressure exceeding external air pressure. This avoids contamination of the battery cell exterior and the generation of defective products, thus helping to reduce production costs and improve injection efficiency. Therefore, it achieves the technical effect of improving injection efficiency and reducing production costs. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic diagram of the structure of a liquid injection device provided in an embodiment of the present invention.
[0019] Figure 2 This is a schematic diagram of the structure of a battery cell cover plate provided in an embodiment of the present utility model.
[0020] Figure 3 This is a schematic diagram of the structure of a battery provided for an embodiment of the present utility model.
[0021] Figure 4 This is a schematic diagram of the structure of a vacuum pump and a pressure sensor in a liquid injection device provided for an embodiment of this utility model.
[0022] Figure 5 This is a schematic diagram of the structure of an automatic control valve in a liquid injection device provided for an embodiment of this utility model. Detailed Implementation
[0023] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0024] To enable those skilled in the art to better understand the solutions of this application, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.
[0025] In the embodiments of this application, "at least one" refers to one or more; "multiple" refers to two or more. In the description of this application, the terms "first," "second," "third," etc., are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance, nor should they be construed as indicating or implying order.
[0026] In this specification, references such as "one embodiment" or "some embodiments" mean that one or more embodiments of this application include the specific features, structures, or characteristics described in connection with that embodiment. Therefore, the terms "comprising," "including," "having," and variations thereof in this specification all mean "including but not limited to," unless otherwise specifically emphasized. It should be noted that in the embodiments of this application, "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone.
[0027] It should be noted that, in the embodiments of this utility model, when a component is referred to as being "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is considered to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. When a component is considered to be "set on" another component, it can be directly set on the other component or there may be an intervening component. Furthermore, in the embodiments of this application, "connection" can also be understood as an electrical connection; the connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components. The terms "vertical," "horizontal," "left," "right," and similar expressions used in the embodiments of this utility model are for illustrative purposes only and are not intended to limit the utility model.
[0028] The first embodiment of this utility model provides a liquid injection device, please refer to... Figure 1 , Figure 4 and Figure 5 As shown, Figure 1 This is a schematic diagram of the structure of a liquid injection device provided in an embodiment of this utility model. Figure 4 This is a schematic diagram of the structure of the vacuum pump 4 and the pressure sensor 6 in a liquid injection device provided in an embodiment of this utility model. Figure 5 This is a schematic diagram of the automatic control valve 5 in a liquid injection device provided in this embodiment of the present invention. The liquid injection device provided in this embodiment of the present invention includes a sealing element 1, an injection needle 2, a vacuum needle 3, and a vacuum pump 4. The sealing element 1 has an inlet hole 11 and an outlet hole 12. The injection needle 2 penetrates the inlet hole 11 and is used to inject electrolyte into the battery cell. The vacuum needle 3 is connected in parallel with the injection needle 2 and penetrates the outlet hole 12. The length of the vacuum needle 3 protruding into the battery cell is less than the length of the injection needle 2 protruding into the battery cell. The vacuum pump 4 is connected to the vacuum needle 3 through a vacuum pipe. During the liquid injection process of the injection needle 2, the vacuum pump 4 extracts gas from inside the battery cell through the vacuum needle 3. The length of the vacuum needle 3 protruding into the battery cell refers to the distance between the end of the vacuum needle 3 protruding into the battery cell and the bottom side of the sealing element 1. The length of the injection needle 2 protruding into the battery cell refers to the distance between the end of the injection needle 2 protruding into the battery cell and the bottom side of the sealing element 1.
[0029] The sealing element 1 can be made of highly elastic and corrosion-resistant rubber or silicone material, so that the sealing element 1 fits tightly with the liquid injection port of the cell cover plate 7 to prevent electrolyte leakage. The positions of the liquid inlet 11 and the vent 12 on the sealing element 1 are matched with the size and position of the liquid injection needle 2 and the vent needle 3, respectively.
[0030] The injection needle 2 can be hollow, with one end connected to the electrolyte supply system and the other end serving as the injection end. The evacuation needle 3 can also be hollow, with one end connected to an evacuation pipe and the other end serving as the evacuation end, facilitating communication with the inside of the battery cell and effectively extracting gas.
[0031] The vacuum pump 4 can be a rotary vane vacuum pump or a vortex vacuum pump, which allows for stable and efficient extraction of gas from inside the battery cell during the liquid injection process. The vacuum pump 4 is connected to the evacuation needle 3 via an evacuation pipe. Alternatively, the operator can use a handheld pressure gauge to observe changes in the internal pressure of the battery cell. When evacuation is required, the operator activates the vacuum pump 4 to evacuate the gas from inside the battery cell.
[0032] In this embodiment, an injection needle 2 penetrates the inlet hole 11 located in the seal 1 to inject electrolyte into the battery cell. A suction needle 3 penetrates the vent hole 12 located in the seal 1. The suction needle 3 and the injection needle 2 are connected in parallel, with the suction needle 3 penetrating into the battery cell to a lesser extent than the injection needle 2. A vacuum pump 4 is connected to the suction needle 3 via a suction pipe. During the injection process, the vacuum pump 4 extracts gas from inside the battery cell through the suction needle 3. During the injection process, the injection needle 2 injects electrolyte into the battery cell, causing the internal pressure to rise. To maintain internal pressure balance and prevent electrolyte overflow, the suction system consisting of the suction needle 3 and the vacuum pump 4 promptly extracts gas from inside the battery cell, creating a negative pressure environment. The negative pressure environment not only promotes rapid electrolyte penetration and reduces injection time, but also effectively prevents electrolyte from overflowing when the injection needle 2 is withdrawn due to internal pressure exceeding external air pressure. This avoids contamination of the battery cell's appearance and the generation of defective products, thus helping to reduce production costs and improve injection efficiency. Therefore, it achieves the technical effect of improving injection efficiency and reducing production costs.
[0033] In one implementation, the length of the suction needle 3 inserted into the battery cell is one-quarter to three-quarters of the length of the injection needle 2 inserted into the battery cell. By setting the length of the suction needle 3 inserted into the battery cell to one-quarter to three-quarters of the length of the injection needle 2, the suction needle 3 can effectively extract the gas rising inside the battery cell due to electrolyte injection, while avoiding interference with the injection needle 2. Preferably, the length of the suction needle 3 inserted into the battery cell is one-third of the length of the injection needle 2 inserted into the battery cell. During the electrolyte injection process, the suction system composed of the suction needle 3 and the vacuum pump 4 promptly extracts the gas inside the battery cell, creating a negative pressure environment, promoting rapid electrolyte penetration, reducing injection time, and preventing electrolyte overflow.
[0034] In some embodiments, the liquid injection device provided in Embodiment 1 of this utility model further includes an automatic control valve 5 and a pressure sensor 6. The automatic control valve 5 is disposed on the suction needle 3 and is located between the sealing element 1 and the vacuum pump 4. The pressure sensor 6 is disposed on the suction needle 3 and is located between the automatic control valve 5 and the sealing element 1, and is connected to the automatic control valve 5. By setting the automatic control valve 5 and the pressure sensor 6, real-time monitoring and automatic adjustment of the internal pressure of the battery cell can be achieved. During the liquid injection process, when the pressure sensor 6 detects an increase in the internal pressure of the battery cell, the automatic control valve 5 adjusts the suction volume of the suction needle 3 according to the pressure data, so that the internal pressure of the battery cell is stabilized. This not only improves the stability of the liquid injection process, but also promotes the rapid penetration of electrolyte and reduces the risk of electrolyte overflow.
[0035] In some embodiments, the automatic control valve 5 in the liquid injection device provided in Embodiment 1 of this utility model includes a valve 51 and a controller 52. The controller 52 is connected to the valve 51 and a pressure sensor 6 respectively. The valve 51 is disposed on the suction needle 3 and is located between the automatic control valve 5 and the sealing element 1. The pressure sensor 6 is used to collect the internal pressure of the battery cell in real time. The controller 52 receives the internal pressure of the battery cell collected by the pressure sensor 6 and compares the pressure with a first set threshold. When the pressure is greater than the first set threshold, the controller 52 triggers the vacuum pump 4 to work and causes the valve 51 to open. Through the valve 51 and the controller 52, precise control of the internal pressure of the battery cell can be achieved. When the pressure exceeds the first set threshold, the controller 52 automatically triggers the vacuum pump 4 to work and opens the valve 51, timely extracting the gas inside the battery cell and forming a negative pressure environment. This not only allows the electrolyte to quickly and evenly penetrate into the battery cell, but also reduces the possibility of electrolyte overflow, improves the liquid injection efficiency, and reduces the production of defective products.
[0036] In some implementations, the first set threshold value ranges from 10% * P ± 0.5 Pa, where P is standard atmospheric pressure. Specifically limiting the first set threshold to 10% * P ± 0.5 Pa improves the accuracy of internal cell pressure control during electrolyte injection. When the pressure exceeds the first set threshold, the vacuum pump 4 immediately starts and opens valve 51 to evacuate air. If the measured internal cell pressure is greater than (0.1 * P - 0.5 Pa), valve 51 can be started and opened to evacuate air, effectively preventing electrolyte overflow due to excessive pressure, improving injection efficiency, ensuring the quality of electrolyte injection, reducing cell appearance contamination and defective products caused by electrolyte overflow, and lowering production costs.
[0037] In some implementations, the controller 52 compares the gas pressure with a second preset threshold. When the gas pressure is lower than the second preset threshold, the controller 52 triggers the vacuum pump 4 to stop and closes the valve 51. By setting the second preset threshold, intelligent control of the liquid injection process is achieved. During the liquid injection process, when the gas pressure drops below the second preset threshold, a sufficient negative pressure environment is formed inside the reaction cell. At this time, the controller 52 automatically triggers the vacuum pump 4 to stop and closes the valve 51, avoiding unnecessary energy consumption and mechanical wear. This not only improves the stability and reliability of the liquid injection process but also helps to reduce production costs while ensuring that the liquid injection efficiency is not affected.
[0038] In some implementations, the second set threshold value ranges from 5%*P ± 0.5 Pa, where P is standard atmospheric pressure. By precisely setting the second set threshold to 5%*P ± 0.5 Pa, a stable and moderate negative pressure environment can be maintained inside the cell after electrolyte injection. This negative pressure environment effectively prevents electrolyte from overflowing when the injection needle 2 is withdrawn, and also avoids damage to the internal structure of the cell or uneven electrolyte distribution due to excessive air extraction. While maintaining the internal pressure balance of the cell, it improves the stability and safety of the electrolyte injection process, helps reduce the defect rate, lowers production costs, and improves electrolyte injection efficiency.
[0039] To provide a detailed description of the battery cell cover 7 provided by this utility model, the above embodiment 1 provides a detailed description of an injection device. Based on the same utility model concept, this application also provides a battery cell cover 7, as detailed in embodiment 2.
[0040] Please see Figure 2 , Figure 2 This is a schematic diagram of the structure of a battery cell cover 7 provided in an embodiment of the present invention. Embodiment two of the present invention provides a battery cell cover 7, including a cell cover 7 and the aforementioned liquid injection device disposed on the cell cover 7. The cell cover 7 body is provided with a liquid injection port that matches the aforementioned sealing member 1, enabling the liquid injection device to be stably installed and operate normally.
[0041] This utility model provides a battery cell cover plate 7. An injection needle 2 penetrates an inlet hole 11 located in a sealing element 1 to inject electrolyte into the cell. A suction needle 3 penetrates an vent hole 12 located in the sealing element 1. The suction needle 3 and the injection needle 2 are connected in parallel. The length of the suction needle 3 penetrating into the cell is less than the length of the injection needle 2 penetrating into the cell. A vacuum pump 4 is connected to the suction needle 3 through a suction pipe. During the electrolyte injection process, the vacuum pump 4 extracts gas from inside the cell through the suction needle 3. During the electrolyte injection process, the injection needle 2 injects electrolyte into the cell, causing the internal gas pressure to rise. To maintain the internal pressure balance of the cell and prevent electrolyte overflow, the suction system composed of the suction needle 3 and the vacuum pump 4 promptly extracts gas from inside the cell, creating a negative pressure environment. The negative pressure environment not only promotes rapid electrolyte penetration and reduces injection time, but also effectively prevents electrolyte from overflowing when the injection needle 2 is withdrawn due to internal pressure exceeding external air pressure. This avoids contamination of the battery cell's appearance and the generation of defective products, thus helping to reduce production costs and improve injection efficiency. Therefore, it achieves the technical effect of improving injection efficiency and reducing production costs.
[0042] To provide a detailed description of the battery 8 provided by this utility model, the above embodiment 1 provides a detailed description of an injection device. Based on the same utility model concept, this application also provides a battery 8, as detailed in embodiment 3.
[0043] Please see Figure 3 , Figure 3 This is a schematic diagram of the structure of a battery 8 provided in an embodiment of the present invention. Embodiment three of the present invention provides a battery 8, including the aforementioned battery cell cover plate 7. During the assembly of the battery 8, the battery cell cover plate 7 is sealed and installed at the open end of the battery cell, forming a complete battery 8 structure. During the production or maintenance of the battery 8, electrolyte is injected into the battery cell through the aforementioned liquid injection device, while a vacuum needle 3 and a vacuum pump 4 system can be used to maintain the internal pressure balance of the cell.
[0044] This invention provides a battery 8. An injection needle 2 penetrates an inlet hole 11 located in a sealing element 1 to inject electrolyte into the battery cell. A vacuum needle 3 penetrates an vent hole 12 located in the sealing element 1. The vacuum needle 3 and the injection needle 2 are connected in parallel. The length of the vacuum needle 3 penetrating into the battery cell is less than the length of the injection needle 2 penetrating into the battery cell. A vacuum pump 4 is connected to the vacuum needle 3 through a vacuum pipe. During the electrolyte injection process, the vacuum pump 4 extracts gas from inside the battery cell through the vacuum needle 3. During the electrolyte injection process, the injection needle 2 injects electrolyte into the battery cell, causing the internal gas pressure to rise. To maintain the internal gas pressure balance and prevent electrolyte overflow, the vacuum system composed of the vacuum needle 3 and the vacuum pump 4 promptly extracts gas from inside the battery cell, creating a negative pressure environment. The negative pressure environment not only promotes rapid electrolyte penetration and reduces injection time, but also effectively prevents electrolyte from overflowing when the injection needle 2 is withdrawn due to internal pressure exceeding external air pressure. This avoids contamination of the battery cell's appearance and the generation of defective products, thus helping to reduce production costs and improve injection efficiency. Therefore, it achieves the technical effect of improving injection efficiency and reducing production costs.
[0045] In order to provide a detailed description of the electrical equipment provided by this utility model, the above embodiment 1 provides a detailed description of a liquid injection device. Based on the same utility model concept, this application also provides an electrical equipment, as detailed in embodiment 4.
[0046] Embodiment 4 of this utility model provides an electrical device, including the aforementioned battery 8, which is used to provide electrical energy. The electrical device can be any device that requires electrical power, such as an electric vehicle, an electric bicycle, an energy storage system, or a portable electronic device.
[0047] This invention provides an electrical device. An injection needle 2 penetrates an inlet hole 11 located in a sealing element 1 to inject electrolyte into the battery cell. A vacuum needle 3 penetrates an vent hole 12 located in the sealing element 1. The vacuum needle 3 and the injection needle 2 are connected in parallel. The length of the vacuum needle 3 penetrating into the battery cell is less than the length of the injection needle 2 penetrating into the battery cell. A vacuum pump 4 is connected to the vacuum needle 3 through a vacuum pipe. During the injection process, the vacuum pump 4 extracts gas from inside the battery cell through the vacuum needle 3. During the injection process, the injection needle 2 injects electrolyte into the battery cell, causing the internal gas pressure to rise. To maintain the internal pressure balance of the battery cell and prevent electrolyte overflow, the vacuum system composed of the vacuum needle 3 and the vacuum pump 4 promptly extracts gas from inside the battery cell, creating a negative pressure environment. The negative pressure environment not only promotes rapid electrolyte penetration and reduces injection time, but also effectively prevents electrolyte from overflowing when the injection needle 2 is withdrawn due to internal pressure exceeding external air pressure. This avoids contamination of the battery cell's appearance and the generation of defective products, thus helping to reduce production costs and improve injection efficiency. Therefore, it achieves the technical effect of improving injection efficiency and reducing production costs.
[0048] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although this utility model has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solution of this utility model without departing from the spirit and scope of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the claims of this utility model.
Claims
1. A liquid injection device, characterized in that, The electrolyte injection device includes a sealing element with an inlet and an outlet, an injection needle for injecting electrolyte into the cell, a suction needle connected in parallel with the injection needle, and a vacuum pump. The injection needle passes through the inlet, the suction needle passes through the outlet, and the length of the suction needle protruding into the cell is less than the length of the injection needle protruding into the cell. The vacuum pump is connected to the suction needle through a suction pipe. During the electrolyte injection process, the vacuum pump extracts gas from inside the cell through the suction needle.
2. The liquid injection device according to claim 1, characterized in that, The length of the suction needle probing into the cell is one-quarter to three-quarters of the length of the injection needle probing into the cell.
3. The liquid injection device according to claim 1, characterized in that, The liquid injection device further includes an automatic control valve and a pressure sensor. The automatic control valve is disposed on the suction needle and is located between the seal and the vacuum pump. The pressure sensor is disposed on the suction needle and is located between the automatic control valve and the seal. The pressure sensor is connected to the automatic control valve.
4. The liquid injection device according to claim 3, characterized in that, The automatic control valve includes a valve and a controller connected to the valve and the pressure sensor respectively. The valve is disposed on the suction needle and is located between the automatic control valve and the seal. The pressure sensor is used to collect the air pressure inside the battery cell in real time. The controller receives the air pressure inside the battery cell collected by the pressure sensor and compares the air pressure with a first set threshold. When the air pressure is greater than the first set threshold, the controller triggers the vacuum pump to work and the valve opens.
5. The liquid injection device according to claim 4, characterized in that, The first set threshold value ranges from 10% * P ± 0.5 Pa, where P is standard atmospheric pressure.
6. The liquid injection device according to claim 4, characterized in that, The controller compares the air pressure with a second set threshold. When the air pressure is less than the second set threshold, the controller triggers the vacuum pump to stop and the valve to close.
7. The liquid injection device according to claim 6, characterized in that, The second set threshold value range is 5% * P ± 0.5 Pa, where P is standard atmospheric pressure.
8. A battery cell cover plate, characterized in that, It includes a cell cover plate and a liquid injection device disposed on the cell cover plate as described in any one of claims 1 to 7.
9. A battery, characterized in that, Includes the battery cell cover plate as described in claim 8.
10. An electrical appliance, characterized in that, Includes the battery as described in claim 9, wherein the battery is used to provide electrical energy.