Liquid injection method and liquid injection equipment

Abstract

The embodiment of the invention provides a liquid injection method and liquid injection equipment. The liquid injection equipment comprises a liquid injection device and a vacuumizing device, the liquid injection device is provided with a containing cavity, and the containing cavity is used for containing electrolyte; the vacuumizing device is used for extracting air from the interior of the battery and forming negative pressure when the electrolyte injection device is communicated with the interior of the battery, so that the electrolyte enters the interior of the battery. The liquid injection method comprises the following steps: providing a vacuumizing device and a liquid injection device; the vacuumizing device and the liquid injection device are connected to the battery; when the vacuumizing device and the liquid injection device are kept to be communicated with the interior of the battery, the vacuumizing device is started, so that negative pressure is formed in the battery, and the electrolyte contained in the liquid injection device enters the interior of the battery. According to the method and the equipment provided by the embodiment of the invention, the problem of low efficiency of liquid injection of the existing battery is solved, and the production efficiency of the battery is improved.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a liquid injection method and liquid injection equipment. Background Art

[0002] With the advancement of electric vehicle technology, electric vehicles are becoming increasingly common as a means of transportation. Batteries, as a key energy source for electric vehicles, are crucial for the sustainable development of the electric vehicle industry due to their energy-saving and environmentally friendly advantages. Therefore, controlling battery production costs is directly related to the production costs of electric vehicles.

[0003] Currently, battery production efficiency needs to be improved. Summary of the Invention

[0004] The embodiments of the present application provide a liquid injection method and liquid injection equipment to improve the liquid injection efficiency of a battery, thereby improving the production efficiency of the battery.

[0005] In a first aspect, an embodiment of the present application provides a liquid injection method for injecting electrolyte into the interior of a battery, the liquid injection method comprising: providing a vacuum pumping device and a liquid injection device; connecting the vacuum pumping device and the liquid injection device to the battery; while maintaining the vacuum pumping device and the liquid injection device in communication with the interior of the battery, starting the vacuum pumping device to form a negative pressure inside the battery, thereby allowing the electrolyte contained in the liquid injection device to enter the interior of the battery.

[0006] In the above technical solution, a vacuum pump and a liquid injection device are simultaneously connected to the interior of the battery. In this state, the vacuum pump is activated. As the vacuum pump operates, the air inside the battery decreases, and the pressure inside the battery becomes negative. Based on this negative pressure, the electrolyte contained in the liquid injection device enters the interior of the battery. As the vacuum pump continues to operate, the electrolyte is continuously injected into the interior of the battery. In this way, the liquid injection process is performed simultaneously with the vacuum pump, and the liquid injection and vacuum pumping operations overlap, reducing the additional time required for either operation. Compared to the traditional breathing multi-step liquid injection method, this liquid injection method not only eliminates the dwell time required to switch between vacuum pumping and liquid injection, but also allows the battery interior to be injected while the vacuum pump is being evacuated to maintain a negative pressure. This allows the liquid injection process to overlap, further reducing the time cost required for liquid injection and improving liquid injection efficiency.

[0007] In some embodiments, a liquid injection hole and an air extraction hole are provided on the outer shell of the battery; connecting the vacuum extraction device and the liquid injection device to the battery includes: connecting the vacuum extraction device to the air extraction hole so that the vacuum extraction device is connected to the interior of the battery; connecting the liquid injection device to the liquid injection hole so that the liquid injection device is connected to the interior of the battery.

[0008] In the above technical solution, there are respectively a liquid injection hole and an air extraction hole on the outer shell of the battery. The liquid injection device is connected to the liquid injection hole, specifically, the electrolyte liquid outlet end of the liquid injection device is connected to the interior of the battery; at the same time, the vacuum device is connected to the air extraction hole, specifically, the air inlet end of the vacuum device is connected to the interior of the battery. The hole for liquid injection on the outer shell of the battery: the liquid injection hole and the hole for air extraction: the air extraction hole, are independent of each other. During implementation, two holes are processed on the outer shell of the battery for liquid injection and air extraction respectively. This can not only meet the internal air extraction and liquid injection needs of the battery, but also does not need to consider the layout of the liquid injection device and the vacuum extraction device due to the limitation of the operating space, and is easy to operate.

[0009] In some embodiments, after the electrolyte contained in the injection device enters the interior of the battery, the injection method further includes: providing a first seal and using the first seal to seal the injection hole; providing a second seal and using the second seal to seal the exhaust hole.

[0010] In the above technical solution, after the battery is filled with liquid, the liquid injection hole and the exhaust hole on the battery shell need to be sealed to seal these two parts and meet the requirements for the subsequent normal operation of the battery. When sealing the liquid injection hole, a first sealing member is placed in the liquid injection hole and the liquid injection hole is sealed by an interference fit, welding, etc. to ensure that the liquid injection hole is blocked. A second sealing member is placed in the exhaust hole and the exhaust hole is sealed by an interference fit, welding, etc. to ensure that the exhaust hole is blocked.

[0011] In some embodiments, a liquid injection hole is provided on the outer shell of the battery; connecting the vacuum pumping device and the liquid injection device to the battery includes: connecting the liquid injection device and the vacuum pumping device to the liquid injection hole so that the vacuum pumping device and the liquid injection device are both connected to the interior of the battery.

[0012] In the above technical solution, both the liquid injection device and the vacuum extraction device are connected to the liquid injection hole. This eliminates the need for adding a vacuum extraction hole in the battery casing; the existing liquid injection hole can be used for both liquid injection and vacuum extraction. Compared to solutions that provide separate liquid injection and vacuum extraction holes, this implementation eliminates the need for machining one hole in the battery casing, thereby better ensuring the strength of the battery casing. It also allows only one hole to be sealed later, reducing the number of necessary steps, improving work efficiency, and reducing the time and cost required for liquid injection.

[0013] In some embodiments, after the electrolyte injection is completed, the injection method includes: providing a first sealing member, and using the first sealing member to seal the injection hole.

[0014] In the above technical solution, after the battery is filled with liquid, the liquid filling hole on the battery casing needs to be sealed to ensure the liquid filling hole is sealed and meet the requirements for subsequent normal operation of the battery. When sealing the liquid filling hole, a first sealing member is placed in the liquid filling hole, and then the liquid filling hole is sealed using an interference fit, welding, or other methods.

[0015] In a second aspect, an embodiment of the present application provides a liquid injection device for injecting electrolyte into the interior of a battery, comprising a liquid injection device and a vacuum pumping device, wherein the liquid injection device is provided with a accommodating chamber for accommodating the electrolyte; the vacuum pumping device is used to evacuate the interior of the battery and form a negative pressure when the liquid injection device is connected to the interior of the battery, thereby allowing the electrolyte to enter the interior of the battery.

[0016] In the above technical solution, the liquid injection device and the vacuum device are simultaneously connected to the interior of the battery. In this state, the vacuum device is started. As the vacuum device works, the air inside the battery is reduced, and the pressure inside the battery becomes negative. Then, based on this negative pressure, the electrolyte contained in the liquid injection device enters the interior of the battery. As the vacuum device continues to work, the electrolyte is continuously injected into the interior of the battery until the liquid injection operation is completed. Compared with traditional liquid injection equipment, the use of this liquid injection equipment not only eliminates the dwell time required for switching between vacuuming and liquid injection, but also injects liquid into the interior of the battery while evacuating the interior of the battery to maintain a negative pressure. The two processes overlap, further reducing the time cost required for liquid injection and improving the efficiency of liquid injection.

[0017] In some embodiments, the vacuum pumping device includes a vacuum pumping tube and a vacuum pump, one end of the vacuum pumping tube is connected to the vacuum pump, and the other end is used to communicate with the interior of the battery.

[0018] In the above technical solution, the vacuum pump in the vacuum pumping device is a component that applies suction to the gas inside the battery, thereby extracting the gas inside the battery. The vacuum pump is connected to the interior of the battery through a vacuum pumping tube. When the vacuum pump is started, the vacuum pump extracts the gas inside the vacuum pumping tube. The end of the vacuum pumping tube connected to the interior of the battery continuously takes in air, and the gas inside the battery continuously enters the vacuum pumping tube and is extracted by the vacuum pump, thereby reducing the amount of gas inside the battery, and then reducing the internal pressure of the battery so that it is in a negative pressure state, so that the electrolyte in the accommodating chamber of the liquid injection device enters the interior of the battery.

[0019] In some embodiments, the injection device includes a main body and an injection tube, the main body is provided with the accommodating cavity; the injection tube is connected to the main body, one end of the injection tube is connected to the accommodating cavity, and the other end is used to be inserted into the injection hole of the battery and connected to the interior of the battery.

[0020] In the above technical solution, the accommodating cavity contains electrolyte. When the electrolyte is injected into the interior of the battery, the bottom end of the injection tube is the outlet end for the electrolyte to flow out. The bottom end of the injection tube is inserted into the injection hole of the battery and the battery is injected, that is, the outlet end does not contact the battery casing. The electrolyte in the accommodating cavity directly enters the interior of the battery through the injection tube. This can avoid the electrolyte from leaking into the top cover of the battery during the injection process, thereby preventing the electrolyte from leaking and contaminating the battery during injection.

[0021] In some embodiments, the vacuum pumping device includes a vacuum pumping tube, a vacuum pump and a reflux component, one end of the vacuum pumping tube is connected to the vacuum pump through the reflux component, and the other end is used to communicate with the interior of the battery.

[0022] In the above technical solution, the vacuum pump in the vacuum device is a power component, which is connected to the interior of the battery through a vacuum tube. When the vacuum pump is started, the vacuum pump evacuates the gas inside the vacuum tube. The end of the vacuum tube connected to the interior of the battery continuously takes in air, and the gas inside the battery continuously enters the vacuum tube and is evacuated by the vacuum pump, thereby reducing the amount of gas inside the battery, and then reducing the internal pressure of the battery to a negative pressure state, so that the electrolyte in the receiving chamber of the injection device enters the interior of the battery. At the same time, one end of the vacuum tube is connected to the vacuum pump through the reflux component. In this way, when the fluid extracted by the vacuum device contains not only air but also a portion of electrolyte, the reflux component collects the electrolyte when the fluid extracted by the vacuum device enters the reflux component. This can not only prevent the electrolyte from being directly discharged by the vacuum device and causing contamination, but also collect the electrolyte extracted by the vacuum device to avoid waste of electrolyte.

[0023] In some embodiments, an injection hole and an exhaust hole are provided on the outer shell of the battery; the end of the vacuum tube away from the vacuum pump is connected to the exhaust hole; the end of the body away from the accommodating cavity is in contact with the outer shell of the battery, and the injection tube is inserted into the injection hole.

[0024] In the above technical solution, the liquid injection tube and the vacuum pumping tube are respectively connected to two different parts of the battery shell, so that the liquid discharge device and the vacuum pumping device are completely independent, making the installation and use of the two devices more convenient, without considering the interference and space concession between the two during installation.

[0025] In some embodiments, the center distance between the liquid injection hole and the air extraction hole is L1, which satisfies 10 mm ≤ L1 ≤ 300 mm.

[0026] In the above technical solution, the spacing between the injection hole and the air extraction hole is too small. After the electrolyte is directly extracted from the injection tube by the vacuum device, it will directly enter the vacuum tube and be directly extracted by the vacuum device. Therefore, based on the above considerations, the center-to-center spacing between the injection hole and the air extraction hole is set to no less than 10mm.

[0027] In some embodiments, 12 mm ≤ L1 ≤ 30 mm.

[0028] In some embodiments, the battery housing is provided with an injection hole, and a portion of the vacuum pump tube, distal from the vacuum pump, is sleeved over the injection tube. Both the vacuum pump tube and the injection tube are inserted into the injection hole to communicate with the interior of the battery. An annulus is formed between the inner wall of the vacuum pump tube and the outer wall of the injection tube, providing a gas flow channel for the vacuum pump to evacuate the interior of the battery.

[0029] In the above technical solution, the section of the vacuum tube away from the vacuum pump is the air inlet of the vacuum device, and the section of the liquid injection tube away from the accommodating chamber is the liquid outlet of the liquid injection device. In the technical solution of this embodiment, these two sections are sleeved, specifically the vacuum tube is sleeved on the liquid injection tube, so that vacuuming and liquid injection can share a hole position on the battery shell, and the hole position can directly use the existing liquid injection hole on the battery shell. In this way, there is no need to add channels to the battery shell. Compared with the solution of separately setting the liquid injection hole and the air extraction hole, this implementation method can not only reduce the processing of one hole on the battery shell, better ensure the strength of the battery shell, but also only need to seal one hole when the hole is subsequently blocked, reducing the necessary operating steps, improving work efficiency, and reducing the time cost required for liquid injection.

[0030] In some embodiments, an end of the liquid injection tube connected to the interior of the battery extends beyond an end of the vacuum tube connected to the interior of the battery.

[0031] In the above technical solution, the liquid injection tube passes through the vacuum tube. In this way, when the vacuum operation is performed to make the interior of the battery into a negative pressure state, the vacuum device first extracts the gas inside the battery instead of the air at the liquid outlet port of the liquid injection tube, thereby avoiding the electrolyte from being drawn into the vacuum device.

[0032] In some embodiments, the length of the liquid outlet tube extending beyond the vacuum tube is L, which satisfies 5mm≤L≤10mm.

[0033] In some embodiments, 6 mm ≤ L ≤ 9 mm is satisfied.

[0034] In the above technical solution, if the length of the liquid outlet pipe extending from the vacuum tube is too short, some electrolyte can be easily drawn directly from the liquid outlet pipe into the vacuum tube by the vacuum device, hindering rapid liquid injection. If the length of the liquid outlet pipe extending from the vacuum tube is too long, the space at the top of the battery will be too large to accommodate the length of the liquid outlet pipe, resulting in low battery energy density. Therefore, when both meeting the requirements of liquid injection and maximizing the battery's energy density, an appropriate length of the liquid outlet pipe extending from the vacuum tube is selected. Within this range, the longer the length of the liquid outlet pipe extending from the vacuum tube, the greater the negative pressure that can be used for liquid injection without causing electrolyte vaporization, thereby improving liquid injection efficiency.

[0035] In some embodiments, the ratio of the inner diameter of the vacuum tube to the inner diameter of the liquid injection tube is not less than 125%.

[0036] In the above technical solution, the vacuum tube is used to exhaust gas from the battery's interior, while the liquid injection tube is used to inject liquid into the battery. Since the vacuum tube needs to be inserted into the liquid injection hole, its outer diameter is smaller than the minimum diameter of the liquid injection hole, while its inner diameter is larger than the outer diameter of the liquid injection tube. The liquid injection tube is a thin-walled metal tube, so its inner diameter is larger than that of the liquid injection tube.

[0037] In some embodiments, a first through hole is provided on the wall of the vacuum tube, and the first through hole is located on a side of the vacuum tube close to the accommodating cavity, and the injection tube extends into the vacuum tube through the first through hole.

[0038] In the above technical solution, an optional embodiment for sleeve-mounting the section of the vacuum tube away from the vacuum pump over the section of the liquid injection tube away from the accommodating chamber is as follows: the end of the liquid injection tube away from the accommodating chamber passes through the upper side wall of the vacuum tube through the first through-hole, is located within the air inlet section of the vacuum tube, and then exits the vacuum tube through the air inlet port of the vacuum tube. By sleeve-mounting the section of the vacuum tube over the liquid injection tube in this manner, the vacuum tube and the liquid injection tube share a common liquid injection hole, eliminating the need to enlarge the liquid injection hole or add a new hole in the battery casing, thereby ensuring the strength of the battery casing. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0040] Figure 1 A schematic flow chart of a liquid injection method according to some embodiments of the present application;

[0041] Figure 2 is a schematic flow chart of a liquid injection method provided according to other embodiments of the present application;

[0042] Figure 3 is a schematic flow chart of a liquid injection method provided according to some further embodiments of the present application;

[0043] Figure 4 Schematic diagram of the liquid injection method of some embodiments of the present application;

[0044] Figure 5 Schematic diagrams of injection methods of other embodiments of the present application;

[0045] Figure 6 This is a schematic diagram of the top cover after the liquid injection operation is completed in some embodiments of the present application;

[0046] Figure 7 Schematic diagram of the top cover after the liquid injection operation is completed in other embodiments of the present application;

[0047] Figure 8 Schematic diagram of a liquid injection device according to some embodiments of the present application;

[0048] Figure 9 Schematic diagrams of liquid injection devices according to other embodiments of the present application;

[0049] Figure 10 for Figure 9 Enlarged view of point A in the middle;

[0050] Figure 11 It is a structural diagram of a section of the vacuum tube that cooperates with the main body;

[0051] Figure 12 It is a structural diagram of the hole for the main body to cooperate with the vacuum tube.

[0052] Icons: 1-liquid injection device; 2-vacuum extraction device; 3-interior of the battery; 4-outer shell; 5-liquid injection hole; 6-exhaust hole; 701-first sealing member; 702-second sealing member; 8-accommodating chamber; 9-vacuum extraction tube; 901-vertical section; 902-bending section; 903-extension section; 904-first through hole; 10-vacuum pump; 11-body; 12-liquid injection tube; 13-reflux component; 14-second through hole; 1401-first section; 1402-second section; 1403-third section; 15-third through hole; 16-first sealing ring installation groove; 17-second sealing ring installation groove; 18-first sealing ring; 19-second sealing ring; 20-sealing pad. DETAILED DESCRIPTION

[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0054] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments in the present application without creative work are within the scope of protection of the present application.

[0055] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0056] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0057] In the description of the embodiments of the present application, it should be noted that the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the application is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are merely for the convenience of describing the present application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present application. In addition, the terms "first," "second," "third," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0058] In the description of the embodiments of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0059] Traditionally, power batteries have been widely used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants. However, with technological advancements and environmental protection requirements, power batteries are now widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As the application areas of power batteries continue to expand, market demand is also increasing. Therefore, effectively improving battery production efficiency has always been a constant pursuit in battery production. Battery production involves many processes, such as electrode manufacturing, battery casing fabrication, and battery filling. Among them, battery filling is a very important process step in battery production. Battery filling mainly involves, after battery assembly, a vacuum device evacuates the battery interior to create a negative pressure. Then, a liquid filling device injects electrolyte into the battery through the filling port in the battery casing. The vacuum device then evacuates the battery interior again to create a negative pressure. The liquid filling device then injects electrolyte into the battery, repeating this cycle until the battery filling is complete.

[0060] The electrolyte injection device used in the battery injection process includes a main body, which can be a nozzle, and a chamber for storing electrolyte. To inject electrolyte into the battery, the vacuum pump must first be activated to evacuate the battery, and then the electrolyte is injected into the battery. Specifically, the electrolyte in the chamber is injected into the battery through the nozzle. In this injection process, the vacuum pump's air extraction port and the liquid discharge port of the injection device are the same port. This means that when injecting electrolyte into the battery's interior, the vacuum pump must first be activated to evacuate the battery's interior, then deactivated, and the electrolyte injected. The electrolyte injection process is then paused, and the vacuum pump is activated again to evacuate the battery's interior, and the electrolyte injected is then injected. This cycle repeats until the electrolyte injection process is complete. This one-step injection method is also known as the breathing multi-step method. However, the breathing multi-step method involves a time gap: the vacuum pumping and injection processes occur in two separate phases, requiring one to cease before the other. When this breathing method is used to inject liquid, the injection and vacuum operation time periods do not overlap, and there is a time gap when the two are switched, resulting in low injection efficiency, which in turn reduces battery production efficiency and causes a high time cost when injecting batteries.

[0061] To improve battery production efficiency, the present invention addresses the independence of the devices involved in the two operations of liquid injection and vacuuming, and analyzes the time distribution characteristics of these two operations. It is found that when vacuuming the battery's interior, liquid injection is paused, and when liquid is injected into the battery, vacuuming is paused. Vacuuming and liquid injection, except for a common port at one end of the battery's interior, are all independent structures. Both vacuuming and liquid injection in the battery's liquid injection operation are related to the vacuuming device. Therefore, the present invention combines the two operations of liquid injection and vacuuming, making the liquid outlet port and the air extraction port involved in these two operations independent of each other, and designing a solution that can greatly save liquid injection time. Specifically, the present invention makes the vacuuming pipeline and the liquid injection pipeline independent of each other, so that when injecting liquid into the battery, the vacuuming device can continue to vacuum the battery's interior, and while the vacuuming device continues to vacuum the battery's interior, the battery's interior continues to be injected with liquid, so that the vacuuming and liquid injection operations are carried out simultaneously, achieving negative pressure extraction and liquid injection simultaneously. This can eliminate the time gap during the existing liquid injection and vacuum pumping cycle operations, and the liquid injection and vacuum pumping operations can be carried out simultaneously, that is, the time of the liquid injection and vacuum pumping operations overlap, thereby eliminating the extra time required for one of the operations, thereby improving the battery liquid injection efficiency, improving the battery production efficiency, and reducing related production costs.

[0062] Based on the above, in order to solve the technical problem of the time gap caused by liquid injection in battery production, which in turn leads to low battery liquid injection efficiency, the liquid injection method disclosed in the embodiment of the present application performs vacuum pumping and liquid injection operations simultaneously, and realizes negative pressure pumping and liquid injection simultaneously, which greatly improves the battery liquid injection efficiency.

[0063] The liquid injection method and liquid injection device disclosed in the embodiments of the present application effectively improve the battery injection efficiency, reduce the battery production cost, and are beneficial to the cost control of electric vehicles and other electrical devices that require this battery.

[0064] As an example, the interior of the battery of the embodiment of the present application is specifically the inner cavity of a battery cell. A battery cell is the smallest unit of a battery. The battery cell may be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell or a battery cell of other shapes. Prismatic battery cells include square-shell battery cells, blade-shaped battery cells, and polygonal prismatic batteries. Polygonal prismatic batteries are, for example, hexagonal prismatic batteries, etc. There are no special restrictions in the embodiments of the present application. The outer shell of the battery includes a top cover and a shell. The shell is provided with an opening. The top cover closes the opening to form an enclosed space for accommodating substances such as electrode assemblies and electrolytes. The injection hole is provided on the top cover. The parts for connecting with the injection device and the vacuum device are both provided on the top cover.

[0065] As an example, a vacuum pump is a device used to evacuate a cavity to reduce the pressure inside the cavity. Its core component may optionally include a vacuum pump, and the air inlet of the vacuum pump is connected to the vacuumed cavity through a vacuum pipe.

[0066] As an example, the liquid injection device is a device for injecting liquid into a battery, which may optionally have a receiving cavity for receiving electrolyte, such as a liquid injection nozzle.

[0067] As an example, the reflux component is also called a reflux tank or a gas-liquid separator. In this embodiment, it is used to separate the electrolyte and gas extracted by the vacuum device and collect the electrolyte.

[0068] For the convenience of description, the following embodiments are described by taking a liquid injection method according to an embodiment of the present application as an example.

[0069] The present application provides a method for injecting liquid. Figure 1 As shown, Figure 1 This is a schematic flow chart of a liquid injection method according to some embodiments of the present application. This liquid injection method is used to inject electrolyte into the interior 3 of the battery, and the liquid injection method includes:

[0070] S100, providing a vacuum pumping device 2 and a liquid injection device 1;

[0071] S200, connecting the vacuum device 2 and the liquid injection device 1 to the battery;

[0072] S300 , while keeping the vacuuming device 2 and the liquid injection device 1 connected to the interior 3 of the battery, start the vacuuming device 2 to form a negative pressure in the interior 3 of the battery, so that the electrolyte contained in the liquid injection device 1 enters the interior 3 of the battery.

[0073] In the technical solution of the embodiment of the present application, a vacuum pump 2 and a liquid injection device 1 are simultaneously connected to the interior 3 of the battery. In this state, the vacuum pump 2 is activated. As the vacuum pump 2 operates, the air in the interior 3 of the battery decreases, and the pressure in the interior 3 of the battery becomes negative. Based on this negative pressure, the electrolyte contained in the liquid injection device 1 enters the interior 3 of the battery. As the vacuum pump 2 continues to operate, the electrolyte is continuously injected into the interior 3 of the battery. When liquid injection is performed during vacuum pumping, the exhaust path of the vacuum pump 2 and the liquid injection path of the liquid injection device 1 are not shared. That is, the exhaust path of the vacuum pump 2 is used for exhaust, not for electrolyte circulation, and the liquid injection path of the liquid injection device 1 is used only for liquid injection, not for gas exhaust.

[0074] In this way, the pipelines for electrolyte flow required for liquid injection and the exhaust pipelines involved in vacuuming are separated from each other, and liquid injection is carried out while vacuuming is being carried out, so that the liquid injection and vacuuming operations can be carried out simultaneously, and the time of the liquid injection and vacuuming operations is overlapped, thereby reducing the additional time required for one of the operations. Compared with the traditional breathing multi-step liquid injection method, this liquid injection method not only eliminates the dwell time required for switching between vacuuming and liquid injection, but also injects liquid into the interior 3 of the battery while vacuuming and maintaining a negative pressure. In this way, the time of vacuuming and maintaining a negative pressure while the liquid is injected is overlapped, further reducing the time cost required for liquid injection, improving the liquid injection efficiency, and then improving the production efficiency of the battery.

[0075] In some embodiments, as Figure 2 and Figure 4 As shown, Figure 2 is a schematic flow chart of a liquid injection method according to some other embodiments of the present application. Figure 4 Schematic diagram of the liquid injection method of some embodiments of the present application, wherein the battery housing 4 is provided with a liquid injection hole 5 and an air extraction hole 6;

[0076] Step S200, connecting the vacuum pumping device 2 and the liquid injection device 1 to the battery, includes:

[0077] S201, connecting the vacuum pumping device 2 to the air extraction hole 6, so that the vacuum pumping device 2 is in communication with the interior 3 of the battery;

[0078] S202 , connecting the liquid injection device 1 to the liquid injection hole 5 , so that the liquid injection device 1 is in communication with the interior 3 of the battery.

[0079] In the battery electrolyte injection operation based on the above steps, it is not necessary to follow the above steps in sequence. In other words, the steps can be performed in the order mentioned in the embodiment, or in a different order than the embodiment, or several steps can be performed simultaneously. For example, steps S201 and S202 can be performed in any order and can be performed simultaneously.

[0080] In the technical solution of the embodiment of this application, Figure 4As shown, the battery housing 4 is provided with a liquid injection hole 5 and an air extraction hole 6. The liquid injection device 1 is connected to the liquid injection hole 5, specifically, the electrolyte outlet of the liquid injection device 1 is connected to the interior 3 of the battery; at the same time, the vacuum extraction device 2 is connected to the air extraction hole 6, specifically, the air inlet of the vacuum extraction device 2 is connected to the interior 3 of the battery. The liquid injection hole 5 and the air extraction hole 6 on the battery housing 4 are independent of each other. During implementation, two holes are machined on the battery housing 4 for liquid injection and air extraction, respectively. This not only meets the requirements of air extraction and liquid injection for the interior 3 of the battery, but also does not require consideration of the layout of the liquid injection device 1 and the vacuum extraction device 2 due to operating space limitations, making operation simple.

[0081] In some embodiments, after the electrolyte contained in the injection device 1 enters the interior 3 of the battery, Figure 6 As shown, Figure 6 This is a schematic diagram of the top cover after the liquid injection operation is completed in some embodiments of the present application. The liquid injection method further includes:

[0082] S401, providing a first sealing member 701, and using the first sealing member 701 to block the injection hole 5;

[0083] S402 , providing a second sealing member 702 , and using the second sealing member 702 to seal the air extraction hole 6 .

[0084] When sealing the hole based on the above steps, it is not necessary to follow the above steps in sequence. In other words, the steps can be performed in the order mentioned in the embodiment, or in a different order than the embodiment, or several steps can be performed simultaneously. For example, steps S401 and S402 can be performed in any order and can be performed simultaneously.

[0085] The partial structure of the battery shell 4 after the injection hole 5 and the air extraction hole 6 are sealed with sealing nails is as follows: Figure 6 As shown, Figure 6 This is a schematic diagram of the top cover after the liquid injection operation is completed in some embodiments of the present application. The top cover of the shell 4 is provided with a liquid injection hole 5 and an air extraction hole 6, and the corresponding holes are sealed with a sealant.

[0086] Based on the above, when the battery housing 4 is provided with a liquid injection hole 5 and an air extraction hole 6, the liquid injection method is as follows:

[0087] S100, providing a vacuum pumping device 2 and a liquid injection device 1;

[0088] S201, connecting the vacuum pumping device 2 to the air extraction hole 6, so that the vacuum pumping device 2 is in communication with the interior 3 of the battery;

[0089] S202, connecting the liquid injection device 1 to the liquid injection hole 5, so that the liquid injection device 1 is in communication with the interior 3 of the battery;

[0090] S300, while maintaining the vacuuming device 2 and the liquid injection device 1 in communication with the interior 3 of the battery, starting the vacuuming device 2 to create a negative pressure in the interior 3 of the battery, thereby allowing the electrolyte contained in the liquid injection device 1 to enter the interior 3 of the battery;

[0091] S401, providing a first sealing member 701, and using the first sealing member 701 to block the injection hole 5;

[0092] S402 , providing a second sealing member 702 , and using the second sealing member 702 to seal the air extraction hole 6 .

[0093] In the technical solution of the embodiment of the present application, the internal liquid of the battery is injected through the liquid injection hole 5, and the internal vacuum of the battery is extracted through the exhaust hole 6; after the liquid injection operation is completed, the liquid injection hole 5 and the exhaust hole 6 on the battery shell 4 need to be sealed to seal these two parts and meet the requirements for the subsequent normal operation of the battery. When sealing the liquid injection hole 5, the first sealing member 701 is placed in the liquid injection hole 5, and the liquid injection hole 5 is sealed by interference fit, welding, etc., so that the liquid injection hole 5 is blocked. The second sealing member 702 is placed in the exhaust hole 6, and the exhaust hole 6 is sealed by interference fit, welding, etc., so that the exhaust hole 6 is blocked.

[0094] In some embodiments, as Figure 3 and Figure 5 As shown, Figure 3 is a schematic flow chart of a liquid injection method provided according to some other embodiments of the present application, Figure 5 Schematic diagram of the liquid injection method of some other embodiments of the present application, wherein the battery housing 4 is provided with a liquid injection hole 5; the vacuum device 2 and the liquid injection device 1 are connected to the battery, including:

[0095] S201, connecting the vacuum pumping device 2 to the liquid injection hole 5, so that the vacuum pumping device 2 is in communication with the interior 3 of the battery;

[0096] S202 , connecting the liquid injection device 1 to the liquid injection hole 5 , so that the liquid injection device 1 is in communication with the interior 3 of the battery.

[0097] In the battery electrolyte injection operation based on the above steps, it is not necessary to follow the above steps in sequence. In other words, the steps can be performed in the order mentioned in the embodiment, or in a different order than the embodiment, or several steps can be performed simultaneously. For example, steps S201 and S202 can be performed in any order and can be performed simultaneously.

[0098] In the technical solution of the embodiment of the present application, the liquid injection device 1 and the vacuum extraction device 2 are both connected to the liquid injection hole 5. In this way, there is no need to add channels on the battery shell 4. The original liquid injection hole 5 can be directly used to perform liquid injection and vacuum extraction operations. Compared with the solution of separately setting the liquid injection hole 5 and the air extraction hole 6, this implementation method can not only reduce the need to process one hole on the battery shell 4, better ensure the strength of the battery shell 4, but also only need to seal one hole when sealing the hole later, reducing the necessary operating steps, improving work efficiency, and reducing the time cost required for liquid injection.

[0099] In some embodiments, as Figure 7 As shown, Figure 7 This is a schematic diagram of the top cover after the liquid injection operation is completed in some other embodiments of the present application. After the electrolyte injection is completed, the liquid injection method includes:

[0100] S400 , providing a first sealing member 701 , and using the first sealing member 701 to seal the liquid injection hole 5 .

[0101] The partial structure of the battery housing 4 after the injection hole 5 is sealed with the first sealing member 701 is as follows: Figure 7 As shown, Figure 7 This is a schematic diagram of the top cover after the liquid injection operation is completed in some other embodiments of the present application. A liquid injection hole 5 is provided on the top cover of the shell 4, and the first sealing member 701 seals the liquid injection hole 5 by interference fit, welding, etc.

[0102] In the technical solution of the embodiment of the present application, after the battery is filled with liquid, the liquid filling hole 5 on the battery housing 4 needs to be sealed to ensure the sealing at the liquid filling hole 5 so that the battery can operate normally. When sealing the liquid filling hole 5, the first sealing member 701 is placed in the liquid filling hole 5, and then the liquid filling hole 5 is sealed by interference fit, welding, etc.

[0103] Based on the above, when the battery housing 4 is provided with a liquid injection hole 5, the liquid injection method is:

[0104] S100, providing a vacuum pumping device 2 and a liquid injection device 1;

[0105] S201, connecting the vacuum pumping device 2 to the liquid injection hole 5, so that the vacuum pumping device 2 is in communication with the interior 3 of the battery;

[0106] S202, connecting the liquid injection device 1 to the liquid injection hole 5, so that the liquid injection device 1 is in communication with the interior 3 of the battery;

[0107] S300, while maintaining the vacuuming device 2 and the liquid injection device 1 in communication with the interior 3 of the battery, starting the vacuuming device 2 to create a negative pressure in the interior 3 of the battery, thereby allowing the electrolyte contained in the liquid injection device 1 to enter the interior 3 of the battery;

[0108] S400 , providing a first sealing member 701 , and using the first sealing member 701 to seal the liquid injection hole 5 .

[0109] In the technical solution of the embodiment of the present application, liquid is injected into the battery through the injection hole 5, and the battery's interior is also vacuumed through the injection hole 5, that is, these two operations share a single hole. The end of the injection device 1 for discharging electrolyte and entering the battery's interior is the injection port, and the end of the vacuum device 2 that communicates with the battery's interior and is used for gas to enter the battery's interior is the exhaust port. When these two ports share the injection hole 5, the injection port and the exhaust port can each occupy a portion of the injection hole 5, or the injection port can be mounted on the exhaust port, or the exhaust port can be mounted on the injection port. In specific implementation, the coordination of these two ports can be adaptively selected based on on-site production conditions. After the battery is injected, the injection hole 5 on the battery housing 4 needs to be sealed to ensure that this area is sealed and meets the requirements for subsequent normal operation of the battery. When sealing the injection hole 5, the first sealing member 701 is placed in the injection hole 5 and sealed by interference fit, welding, or other methods to ensure that the injection hole 5 is blocked.

[0110] In the above, the injection method in which the vacuum device 2 is connected to the inner cavity through the vacuum hole 6 and the injection device 1 is connected to the inner cavity through the injection hole 5 is summarized as the first injection method; the injection method in which both the vacuum device 2 and the injection device 1 are connected to the inner cavity through the injection hole 5 is summarized as the second injection method. The time required for these two methods to complete the injection is shown in the following table, respectively, under the same conditions as the existing breathing multi-step injection method: the hole diameter of the injection hole 5 is 3mm, the vacuum negative pressure is -80kPa, and the electrolyte injection volume is 500g:

[0111]

[0112] Table 1. Injection schedule for three injection methods

[0113] In Table 1, the liquid injection port is the liquid outlet end of the liquid injection device 1. In the first and second embodiments, the vacuum port is the air inlet end of the vacuum tube 9 of the vacuum device 2. In the existing breathing multi-step liquid injection method, the vacuum port is the liquid injection port of the liquid injection device 1, which is the same port as the liquid injection port. Therefore, the diameter of the vacuum port of the existing breathing multi-step liquid injection method is consistent with the diameter of the liquid injection port. In some breathing multi-step methods, during vacuuming, only the vacuum device 2 is connected to the interior 3 of the battery through the liquid injection port; after completing the first round of vacuuming, only the liquid injection device 1 is connected to the interior 3 of the battery through the liquid injection port for liquid injection; after completing the first round of liquid injection, only the vacuum device 2 is connected to the interior 3 of the battery through the liquid injection port for a second round of vacuuming; after completing the second round of vacuuming, only the liquid injection device 1 is connected to the interior 3 of the battery through the liquid injection port for a second round of liquid injection. This cycle continues until the liquid injection operation is completed.

[0114] It can be seen from the above table that under the same injection conditions: the diameter of the injection hole 5 is 3mm, the vacuum negative pressure is -80kPa, and the electrolyte injection volume of 500g is completed. The existing breathing multi-step injection method requires an injection time of 300s, while the first injection method only requires 100s, and the second injection method only requires 90s. The injection time is shortened from the existing 300s to 100s or 90s in this embodiment, which greatly improves the injection efficiency. Compared with the existing injection method, the injection method provided in the embodiment of the present application has a greatly shortened injection time, reduces the time cost required for injection, improves the injection efficiency, and helps to reduce the time cost required for battery production, thereby having a positive effect on controlling the production cost of batteries manufactured by this method for electric vehicles and the like.

[0115] In some embodiments, the time required to complete the injection of 500 g of liquid for the first and second injection methods under different liquid injection port diameters, vacuum port diameters, and vacuum negative pressures is as follows:

[0116]

[0117]

[0118] Table 2. Injection schedule for the two injection methods

[0119] It can be seen from sequence numbers 1 and 2 in Table 2 that for the same liquid injection method, when the liquid injection port size and the vacuum port size are the same, the larger the vacuum negative pressure, the less time is required to complete the same liquid injection volume; it can be seen from sequence numbers 2 and 3 in Table 2 that for the same liquid injection method, when the vacuum port size, the vacuum negative pressure, and the injection volume are the same, the larger the liquid injection port size, the less time is required; it can be seen from sequence numbers 5 and 6 in Table 2 that for the same liquid injection method, when the liquid injection port size, the vacuum negative pressure, and the injection volume are the same, the larger the vacuum port size, the less time is required.

[0120] In the technical solution of the embodiment of the present application, the size of the vacuum port is only related to the size of the vacuum tube 9 of the vacuum device 2 itself. The channel required for vacuuming does not need to involve the liquid outlet channel of the injection device 1. Therefore, different injection ports can be configured according to actual production conditions, which improves the flexibility of the injection method and its adaptability to different injection conditions.

[0121] The embodiment of the present application provides a liquid injection device for injecting electrolyte into the interior 3 of the battery, such as Figure 8 or Figure 9 As shown, Figure 8 This is a schematic diagram of a liquid injection device according to some embodiments of the present application. Figure 9 This is a schematic diagram of the liquid injection device of some other embodiments of the present application, the liquid injection equipment includes a liquid injection device 1 and a vacuum pumping device 2, wherein the liquid injection device 1 is provided with a accommodating chamber 8, and the accommodating chamber 8 is used to accommodate the electrolyte; the vacuum pumping device 2 is used to evacuate the interior 3 of the battery and form a negative pressure when the liquid injection device 1 is connected to the interior 3 of the battery, thereby allowing the electrolyte to enter the interior 3 of the battery.

[0122] In the technical solution of the embodiment of the present application, the liquid injection device 1 and the vacuum device 2 are simultaneously connected to the interior 3 of the battery. In this state, the vacuum device 2 is started. As the vacuum device 2 works, the air in the interior 3 of the battery is reduced, and the pressure in the interior 3 of the battery becomes negative. Then, based on this negative pressure, the electrolyte contained in the liquid injection device 1 enters the interior 3 of the battery. As the vacuum device 2 continues to work, the electrolyte is continuously injected into the interior 3 of the battery until the liquid injection operation is completed. The use of this liquid injection equipment eliminates the dwell time required for switching between vacuuming and liquid injection. In addition, while the interior 3 of the battery is being evacuated to maintain a negative pressure, liquid is injected into the interior 3 of the battery, so that the time for the two operations overlaps, further reducing the time cost required for liquid injection, improving the liquid injection efficiency, and thus improving the production efficiency of the battery.

[0123] In some embodiments, the vacuum pumping device 2 includes a vacuum pumping tube 9 and a vacuum pump 10 , one end of the vacuum pumping tube 9 is connected to the vacuum pump 10 , and the other end is used to communicate with the interior 3 of the battery.

[0124] In the technical solution of the embodiment of the present application, the vacuum pump 10 in the vacuum device 2 is a vacuum pump, which is connected to the interior 3 of the battery through the vacuum tube 9. When the vacuum pump 10 is started, the vacuum pump 10 evacuates the gas inside the vacuum tube 9. The end of the vacuum tube 9 connected to the interior 3 of the battery continuously takes in air, and the gas in the interior 3 of the battery continuously enters the vacuum tube 9 and is evacuated by the vacuum pump 10, thereby reducing the amount of gas in the interior 3 of the battery, and then reducing the pressure in the interior 3 of the battery so that it is in a negative pressure state, so that the electrolyte in the accommodating chamber 8 of the liquid injection device 1 enters the interior 3 of the battery.

[0125] In some embodiments, the injection device 1 includes a main body 11 and an injection tube 12, the main body 11 is provided with the accommodating cavity 8; the injection tube 12 is connected to the main body 11, one end of the injection tube 12 is connected to the accommodating cavity 8, and the other end is used to be inserted into the injection hole 5 of the battery and connected to the interior 3 of the battery.

[0126] In the technical solution of the embodiment of the present application, the accommodating cavity 8 contains electrolyte. When the electrolyte is injected into the interior 3 of the battery, the bottom end of the injection tube 12 is the outlet end for the electrolyte to flow out. The bottom end of the injection tube 12 is inserted into the injection hole 5 of the battery and injected into the interior of the battery, that is, the outlet end will not contact the battery casing 4. The electrolyte in the accommodating cavity 8 directly enters the interior 3 of the battery through the injection tube 12. This can avoid the electrolyte from leaking into the top cover of the battery during the injection process, thereby preventing the electrolyte from leaking and contaminating the battery during injection.

[0127] In some embodiments, the vacuum pumping device 2 includes a vacuum pumping tube 9, a vacuum pump 10 and a reflux component 13. One end of the vacuum pumping tube 9 is connected to the vacuum pump 10 through the reflux component 13, and the other end is used to communicate with the interior 3 of the battery.

[0128] In the technical solution of the embodiment of the present application, the vacuum pump 10 in the vacuum device 2 is a power component. It is connected to the interior 3 of the battery via the vacuum tube 9. When the vacuum pump 10 is activated, the vacuum pump 10 evacuates the gas inside the vacuum tube 9. The end of the vacuum tube 9 connected to the interior 3 of the battery continuously receives air. The gas inside the interior 3 of the battery continuously enters the vacuum tube 9 and is evacuated by the vacuum pump 10, thereby reducing the amount of gas inside the interior 3 of the battery, and then reducing the pressure inside the battery 3 to a negative pressure state, thereby allowing the electrolyte in the receiving chamber 8 of the liquid injection device 1 to enter the interior 3 of the battery. At the same time, one end of the vacuum tube 9 is connected to the vacuum pump 10 via the reflux component 13. In this way, when the fluid extracted by the vacuum device 2 contains not only air but also a portion of electrolyte, the reflux component 13 collects the electrolyte when the fluid extracted by the vacuum device 2 enters the reflux component 13. This not only prevents the electrolyte from being directly discharged by the vacuum device 2 and causing contamination, but also collects the electrolyte extracted by the vacuum device 2 to avoid electrolyte waste.

[0129] In some embodiments, as Figure 4 As shown, the battery housing 4 is provided with a liquid injection hole 5 and an air extraction hole 6; the end of the vacuum tube 9 away from the vacuum pump 10 is connected to the air extraction hole 6; the end of the body 11 away from the accommodating cavity 8 is in contact with the battery housing 4, and the liquid injection tube 12 is inserted into the liquid injection hole 5. The liquid injection equipment includes a liquid injection device 1 and a vacuum extraction device 2, as shown in FIG. Figure 8 As shown, Figure 8 Schematic diagram of the liquid injection device of some embodiments of the present application, wherein the liquid injection device 1 is connected to the liquid injection hole 5, and the vacuum device 2 is connected to the air extraction hole 6, as shown in FIG. Figure 4 shown.

[0130] In the technical solution of the embodiment of the present application, the liquid injection tube 12 and the vacuum tube 9 are respectively connected to two different parts of the battery shell 4, so that the liquid discharge device and the vacuum device 2 are completely independent, making the installation and use of the two devices more convenient, without having to consider the interference and space concession during the installation of the two.

[0131] In some embodiments, the center distance between the liquid injection hole 5 and the air extraction hole 6 is L1, which satisfies

[0132] 10mm≤L1≤300mm.

[0133] In the technical solution of the embodiment of the present application, the spacing between the liquid injection hole 5 and the air extraction hole 6 is too small. After the electrolyte is directly extracted from the liquid injection tube 12 by the vacuum pumping device 2, it will directly enter the vacuum pumping tube 9 and be directly extracted by the vacuum pumping device 2. Therefore, based on the above considerations, the center-to-center spacing between the liquid injection hole 5 and the air extraction hole 6 is set to be no less than 10 mm to prevent air extraction and liquid injection from interfering with each other.

[0134] In some embodiments, 12 mm ≤ L1 ≤ 30 mm.

[0135] In some embodiments, the battery housing 4 is provided with a liquid injection hole 5, such as Figure 5 As shown, a section of the vacuum tube 9 away from the vacuum pump 10 is sleeved onto the liquid injection tube 12. Both the vacuum tube 9 and the liquid injection tube 12 are inserted into the liquid injection hole 5 and communicate with the interior 3 of the battery. An annulus is formed between the inner wall of the vacuum tube 9 and the outer wall of the liquid injection tube 12, which serves as a gas flow channel when the vacuum device 2 evacuates the interior 3 of the battery.

[0136] The liquid injection equipment includes a liquid injection device 1 and a vacuum device 2. Figure 9 and Figure 10 As shown, Figure 9 Schematic diagrams of liquid injection devices according to other embodiments of the present application. Figure 10 for Figure 9 The enlarged view of A in the middle; the liquid injection device 1 and the vacuum device 2 are both connected to the liquid injection hole 5, as Figure 5 shown.

[0137] In the technical solution of the embodiment of the present application, the section of the vacuum tube 9 away from the vacuum pump 10 is the air intake portion of the vacuum device 2, and the section of the liquid injection tube 12 away from the accommodating chamber 8 is the liquid discharge portion of the liquid injection device 1. In the technical solution of this embodiment, these two portions are sheathed, specifically, the vacuum tube 9 is sheathed on the liquid injection tube 12, as shown in FIG. Figure 10 As shown, vacuuming and liquid injection can share a single hole on the battery casing 4. The hole can directly utilize the existing liquid injection hole 5 on the battery casing 4. This eliminates the need for additional channels on the battery casing 4. Compared to solutions with separate liquid injection holes 5 and vacuum holes 6, this embodiment not only eliminates the need for machining one hole on the battery casing 4, better ensuring the strength of the battery casing 4, but also allows only one hole to be sealed later. This reduces the number of necessary steps, improves work efficiency, and reduces the time and cost required for liquid injection.

[0138] In some embodiments, one end of the liquid injection tube 12 communicating with the interior 3 of the battery extends beyond one end of the vacuum tube 9 communicating with the interior 3 of the battery.

[0139] In the technical solution of the embodiment of the present application, the liquid injection tube 12 passes through the vacuum tube 9. In this way, when the vacuum operation is performed to make the interior 3 of the battery into a negative pressure state, the vacuum device 2 first extracts the gas in the interior 3 of the battery, rather than extracting the air at the liquid outlet port of the liquid injection tube 12, which can avoid drawing the electrolyte into the vacuum device 2.

[0140] In some embodiments, the length of the liquid outlet pipe extending beyond the vacuum pipe 9 is L, which satisfies 5mm≤L≤10mm.

[0141] In some embodiments, 6 mm ≤ L ≤ 9 mm.

[0142] In the technical solution of the embodiment of the present application, the length of the liquid outlet pipe passing through the vacuum tube 9 is too short, and part of the electrolyte is easily drawn directly from the liquid outlet pipe into the vacuum tube 9 by the vacuum device 2, which is not conducive to rapid liquid injection; if the length of the liquid outlet pipe passing through the vacuum tube 9 is too long, the vacant space on the top of the battery to match the length of the liquid outlet pipe will be too large, resulting in low battery energy density.

[0143] In the technical solution of the embodiment of the present application, the shorter the length of the injection tube 12 extending from the vacuum tube 9, the more difficult it is to inject the electrolyte into the interior 3 of the battery. The longer the injection tube 12 extends from the vacuum tube 9, the lower the cell height and the lower the battery's energy density to avoid interference. Therefore, when both satisfying the injection requirements and maximizing the battery's energy density, an appropriate length of the injection tube 12 extending from the vacuum tube 9 is sufficient. Within this range, the longer the injection tube 12 extends from the vacuum tube 9, the greater the negative pressure that can be used for injection without causing electrolyte vaporization, thereby improving injection efficiency.

[0144] In some embodiments, the ratio of the inner diameter of the vacuum tube 9 to the inner diameter of the liquid injection tube 12 is not less than 125%.

[0145] In the technical solution of the embodiment of the present application, the vacuum tube 9 is used to discharge the gas from the interior 3 of the battery, and the injection tube 12 is used to inject liquid into the interior 3 of the battery. The vacuum tube 9 needs to be inserted into the injection hole 5, so its outer diameter is smaller than the minimum aperture of the injection hole 5, and its inner diameter is larger than the outer diameter of the injection tube 12. An annulus is formed between the inner wall of the vacuum tube 9 and the outer wall of the injection tube 12, which facilitates the vacuum device 2 to extract the gas from the interior 3 of the battery. The vacuum device 2 evacuates the interior 3 of the battery, and the gas enters between the inner wall of the vacuum tube 9 and the outer wall of the injection tube 12, and then enters the part of the vacuum tube 9 that is not mounted on the injection tube 12, and is finally discharged by the vacuum device. The injection tube 12 is a thin-walled metal tube, so the inner diameter of the vacuum tube 9 is larger than the inner diameter of the injection tube 12.

[0146] In some embodiments, as Figure 11 As shown, Figure 11 This is a structural schematic diagram of a section of the vacuum tube that cooperates with the main body. A first through hole 904 is provided on the tube wall of the vacuum tube 9. The first through hole 904 is located on the side of the vacuum tube 9 close to the accommodating cavity 8. The injection tube 12 extends into the vacuum tube 9 through the first through hole 904.

[0147] In the technical solution of the embodiment of the present application, an optional implementation method for the section of the vacuum tube 9 away from the vacuum pump 10 to be sleeved on the section of the liquid injection tube 12 away from the accommodating chamber 8 is as follows: the end of the liquid injection tube 12 away from the accommodating chamber 8 passes through the upper side wall of the vacuum tube 9 from the first through hole 904 and is located in the air inlet section of the vacuum tube 9, and then passes through the vacuum tube 9 from the air inlet port. By so doing, a section of the vacuum tube 9 is sleeved on the liquid injection tube 12, so that the vacuum tube 9 and the liquid injection tube 12 can share the liquid injection hole 5, eliminating the need to enlarge the liquid injection hole 5 or add a hole in the battery shell 4, thereby ensuring the strength of the battery shell 4.

[0148] In the technical solution of the embodiment of the present application, the embodiment in which the section of the vacuum tube 9 away from the vacuum pump 10 is sheathed over the section of the liquid injection tube 12 away from the accommodating chamber 8 is implemented such that the end of the liquid injection tube 12 away from the accommodating chamber 8 passes through the upper side wall of the vacuum tube 9 and is located in the air inlet section of the vacuum tube 9, and then passes through the vacuum tube 9 from the air inlet port. The section of the vacuum tube 9 away from the vacuum pump 10 and the section of the liquid injection tube 12 away from the accommodating chamber 8 are preferably coaxial in implementation.

[0149] In some embodiments, as Figure 12 As shown, Figure 12 This is a structural diagram of the hole for cooperating between the main body and the vacuum tube, wherein a second through hole 14 and a third through hole 15 are provided on the main body 11, and the second through hole 14 includes a first section 1401, a second section 1402 and a third section 1403. The first section is coaxial with the liquid outlet pipe, and its bottom end is connected to the bottom of the main body 11, and its top end is connected to one end of 1403 through the second section 1402, and the other end of the third section 1403 is connected to the outer wall of the main body 11, and a first sealing ring mounting groove 16 is provided on the inner wall of the third section 1403 on the side away from the second section 1402, and a first sealing ring 18 is provided in the first sealing ring mounting groove 16; the first section 1401 smoothly transitions to the third section 1403 through the second section 1402.

[0150] like Figure 12 As shown, the top end of the third through hole 15 is connected to the accommodating cavity 8, and the bottom end thereof is connected to the second section 1402, and the third through hole 15 is coaxial with the first section 1401. A second sealing ring mounting groove 17 is provided on the side of the hole wall of the third through hole 15 close to the accommodating cavity 8, and a second sealing ring 19 is provided in the second sealing ring mounting groove 17.

[0151] like Figure 11As shown, a section of the vacuum tube 9 away from the vacuum pump 10 includes a vertical section 901, a bent section 902 and an extended section 903 connected in sequence, the vertical section 901 is located in the first section 1401, the bottom end of which passes through the bottom end of the first section 1401, and the top end of which smoothly transitions to the extended section 903 through the bent section 902; the bent section 902 is located in the second section 1402, and the first through hole 904 is provided on the side wall thereof close to the accommodating chamber 8, the extended section 903 is located in the third section 1403, and is sealed with the third section 1403 through a first sealing ring.

[0152] The top end of the injection tube 12 is located in the third through hole 15 and is connected to the accommodating chamber 8. Its outer peripheral surface is sealed with the third through hole 15 through the second sealing ring 19; the bottom end of the injection tube 12 passes through the first through hole 904 and the vertical section 901 and is located below the bottom end of the vacuum tube 9.

[0153] In some embodiments, the area of ​​the injection hole and the area of ​​the top cover are conventionally set in a projection parallel to the electrolyte surface, with the area of ​​the injection hole typically accounting for 5% to 70% of the area of ​​the top cover. Specifically, the diameter of the injection hole should be smaller than the width of the top cover, and to ensure smooth subsequent welding operations to seal the injection hole, the minimum distance between the injection hole wall and the edge of the top cover should be greater than 2 mm.

[0154] In some embodiments, in the projection parallel to the electrolyte surface, the area of ​​the vacuum hole and the area of ​​the top cover are in the following relationship: the area of ​​the vacuum hole accounts for 5%-80% of the area of ​​the top cover. Specifically, the diameter of the vacuum hole should be smaller than the width of the top cover, and in order to ensure the smooth progress of the subsequent welding operation of sealing the injection hole, the minimum distance between the hole wall of the vacuum hole and the edge of the top cover should be greater than 2 mm.

[0155] In some embodiments, a sealing gasket 20 is installed at the bottom end of the body 11. The sealing gasket 20 is installed on the end surface of the body 11. The sealing gasket 20 can be bonded to the body 11, embedded in the body 11, or sleeved on the body 11. During liquid injection, the sealing gasket 20 is compressed between the body 11 and the battery casing 4, and is used to maintain the sealing of the top of the liquid injection hole 5, facilitating smooth liquid injection and air extraction operations.

[0156] In some embodiments, the battery casing 4 is provided with a liquid injection hole 5 and an air extraction hole 6. The liquid injection device for injecting electrolyte into the battery interior 3 includes a liquid injection device 1 and a vacuum device 2. The liquid injection device 1 includes a body 11 and a liquid injection tube 12. The body 11 is provided with a receiving chamber 8. The liquid injection tube 12 is connected to the body 11. The end of the body 11 away from the receiving chamber 8 contacts the battery casing 4. One end of the liquid injection tube 12 communicates with the receiving chamber 8, and the other end is inserted into the battery's liquid injection hole 5 and communicates with the battery's interior 3. The receiving chamber 8 is used to hold the electrolyte. The vacuum device 2 includes a vacuum tube 9, a vacuum pump 10, and a reflux component 13. One end of the vacuum tube 9 is connected to the vacuum pump 10 via the reflux component 13, and the other end is connected to the air extraction hole 6, thereby communicating with the battery's interior 3. The center-to-center distance between the liquid injection hole 5 and the air extraction hole 6 is 15 mm. The vacuum device 2 is used to evacuate the interior 3 of the battery and form a negative pressure when the liquid injection device 1 is connected to the interior 3 of the battery, so that the electrolyte enters the interior 3 of the battery.

[0157] In the technical solution of the embodiment of the present application, while the interior 3 of the battery is evacuated to maintain a negative pressure, liquid is injected into the interior 3 of the battery, so that the negative pressure is maintained while the battery is injected, and the liquid is injected while the negative pressure is maintained. The time of the two is overlapped, which further reduces the time cost required for the injection of liquid, improves the injection efficiency, and thus improves the production efficiency of the battery.

[0158] At the same time, a liquid injection hole 5 and an air extraction hole 6 are provided on the battery shell 4 for liquid injection and air extraction, respectively, so that the liquid injection pipe 12 and the vacuum tube 9 are respectively connected to two different parts of the battery shell 4, so that the liquid discharge device and the vacuum extraction device 2 are completely independent, making the installation and use of the two devices more convenient, without having to consider the interference and space concession during the installation of the two.

[0159] In some embodiments, the battery housing 4 is provided with an injection hole 5, and the injection equipment for injecting electrolyte into the interior 3 of the battery includes an injection device 1 and a vacuum device 2, wherein the injection device 1 includes a body 11 and an injection tube 12, wherein the body 11 is provided with a receiving chamber 8; the injection tube 12 is connected to the body 11, and the end of the body 11 away from the receiving chamber 8 contacts the battery housing 4. One end of the injection tube 12 is connected to the receiving chamber 8, and the other end is used to be inserted into the injection hole 5 of the battery and connected to the interior 3 of the battery. The receiving chamber 8 is used to accommodate electrolyte. The vacuum device 2 includes a vacuum tube 9, a vacuum pump 10, and a reflux component 13. One end of the vacuum tube 9 is connected to the vacuum pump 10 through the reflux component 13, and the other end is inserted into the injection hole 5 and is sleeved on the injection tube 12, that is, the vacuum tube 9 and the injection tube 12 are both inserted into the injection hole 5 and connected to the interior 3 of the battery. The liquid outlet pipe extends beyond the vacuum tube 9 by 8 mm. The ratio of the inner diameter of the vacuum tube 9 to the inner diameter of the liquid injection pipe 12 is 150%. The vacuum device 2 is used to evacuate the interior 3 of the battery and create a negative pressure when the liquid injection device 1 is connected to the interior 3 of the battery, thereby allowing the electrolyte to enter the interior 3 of the battery.

[0160] In the technical solution of the embodiment of the present application, while the interior 3 of the battery is evacuated to maintain a negative pressure, liquid is injected into the interior 3 of the battery, so that the negative pressure is maintained while the battery is injected, and the liquid is injected while the negative pressure is maintained. The time of the two is overlapped, which further reduces the time cost required for the injection of liquid, improves the injection efficiency, and thus improves the production efficiency of the battery.

[0161] At the same time, vacuuming and liquid injection can share the same injection hole for vacuuming and liquid injection, so there is no need to add channels on the battery shell 4, which can better ensure the strength of the battery shell 4. At the same time, when the hole is sealed later, only one hole needs to be sealed, which reduces the necessary operating steps, improves work efficiency, and reduces the time cost required for liquid injection.

[0162] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be substituted with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A method for injecting electrolyte into a battery, characterized in that: include: Provide vacuum extraction device and liquid injection device; connecting the vacuuming device and the liquid injection device to the battery; While the vacuuming device and the liquid injection device are both connected to the interior of the battery, the vacuuming device is started to form a negative pressure inside the battery, so that the electrolyte contained in the liquid injection device enters the interior of the battery.

2. The liquid injection method according to claim 1, characterized in that: The battery shell is provided with a liquid injection hole and an air extraction hole; The step of connecting the vacuum pump and the liquid injection device to the battery comprises: Connecting the vacuum pumping device to the air extraction hole so that the vacuum pumping device is in communication with the interior of the battery; The liquid injection device is connected to the liquid injection hole so that the liquid injection device is communicated with the interior of the battery.

3. The liquid injection method according to claim 2, characterized in that: After the electrolyte contained in the liquid injection device enters the interior of the battery, the liquid injection method further includes: Providing a first sealing member, and using the first sealing member to block the injection hole; A second sealing member is provided, and the air extraction hole is sealed by the second sealing member.

4. The liquid injection method according to claim 1, characterized in that: The battery shell is provided with a liquid injection hole; The step of connecting the vacuum pump and the liquid injection device to the battery comprises: The liquid injection device and the vacuum pumping device are both connected to the liquid injection hole, so that the vacuum pumping device and the liquid injection device are both connected to the interior of the battery.

5. The liquid injection method according to claim 4, characterized in that: After the electrolyte contained in the liquid injection device enters the interior of the battery, the liquid injection method includes: A first sealing member is provided, and the injection hole is sealed by the first sealing member.

6. A liquid injection device for injecting electrolyte into a battery, characterized in that: include: A liquid injection device, provided with a receiving chamber, wherein the receiving chamber is used to receive the electrolyte; The vacuum device is used to evacuate the interior of the battery and form a negative pressure when the liquid injection device is connected to the interior of the battery, so that the electrolyte enters the interior of the battery.

7. The liquid injection device according to claim 6, characterized in that: The vacuum pumping device comprises a vacuum pumping tube and a vacuum pump. One end of the vacuum pumping tube is connected to the vacuum pump, and the other end is used to communicate with the interior of the battery.

8. The liquid injection device according to claim 6, characterized in that: The injection device comprises a body and an injection tube, wherein the body is provided with the accommodating cavity; the injection tube is connected to the body, one end of the injection tube is communicated with the accommodating cavity, and the other end is used for inserting into the injection hole of the battery.

9. The liquid injection device according to claim 8, characterized in that: The vacuum pumping device comprises a vacuum pumping tube, a vacuum pump and a reflux component. One end of the vacuum pumping tube is connected to the vacuum pump through the reflux component, and the other end is used to communicate with the interior of the battery.

10. The liquid injection device according to claim 9, characterized in that: The battery shell is provided with a liquid injection hole and an air extraction hole; One end of the vacuum tube away from the vacuum pump is connected to the air extraction hole; One end of the body away from the accommodating cavity contacts the battery shell, and the injection tube is inserted into the injection hole.

11. The liquid injection device according to claim 10, characterized in that: The center distance between the liquid injection hole and the air extraction hole is L1, which satisfies 10mm≤L1≤300mm.

12. The liquid injection device according to claim 11, characterized in that: 12mm≤L1≤30mm.

13. The liquid injection device according to claim 9, characterized in that: The battery shell is provided with a liquid injection hole, a section of the vacuum tube away from the vacuum pump is sleeved on the liquid injection tube, and both the vacuum tube and the liquid injection tube are inserted into the liquid injection hole and communicated with the interior of the battery.

14. The liquid injection device according to claim 13, characterized in that: One end of the liquid injection tube connected to the interior of the battery is beyond one end of the vacuum tube connected to the interior of the battery.

15. The liquid injection device according to claim 14, characterized in that: The length of the injection tube exceeding the vacuum tube is L, which satisfies: 5mm≤L≤10mm.

16. The liquid injection device according to claim 15, characterized in that: 6mm≤L≤9mm.

17. The liquid injection device according to claim 13, characterized in that: The ratio of the inner diameter of the vacuum tube to the inner diameter of the liquid injection tube is not less than 125%.

18. The liquid injection device according to any one of claims 13 to 17, characterized in that: A first through hole is provided on the tube wall of the vacuum tube. The first through hole is located on a side of the vacuum tube close to the accommodating cavity. The injection tube extends into the vacuum tube through the first through hole.

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