End cover assembly, housing assembly, battery cell, battery and electrical consumption equipment

Abstract

To provide a battery cell end cover assembly that effectively improves the performance of a battery cell, a battery cell, a housing assembly, a battery, and a device using a battery cell.SOLUTION: An end cover assembly used for a battery cell of the present application includes: an end cover that has a through hole to which an electrolyte is injected and a first engagement part (the first engagement part is arranged in a circumferential direction of the through hole and located at one side of the end cover separated from the inside of the battery cell); a seal ring that seals the through hole; and a pressure relaxation device that is destroyed when the internal pressure of the battery cell reaches a threshold to cancel the closing of the through hole, and releases the internal pressure of the battery cell. The pressure relaxation device is rotatable, and includes a second engagement part. When the pressure relaxation device rotates to a first position, the second engagement part is engaged with the first engagement part to restrict the separation of the pressure relaxation device and the end cover from each other, and when the pressure relaxation device rotates to a second position, the second engagement part is disengaged from the first engagement part to separate the pressure relaxation device and the end cover from each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present application relates to the technical field of batteries, and in particular to end cover assemblies, housing assemblies, battery cells, batteries, and electrical consuming equipment. [Background technology]

[0002] Lithium-ion battery cells have advantages such as high energy density, high power density, high cycle density, many cycles, and long storage time, and are therefore widely used in electrical consumption equipment such as electric vehicles. Summary of the Invention [Problem to be solved by the invention]

[0003] The performance of battery cells directly affects the performance of electrical consuming equipment, but how to effectively improve the performance of battery cells has always been a difficult challenge for the industry.

[0004] The purpose of this application is to improve the performance of battery cells. [Means for solving the problem]

[0005] According to a first aspect of the present application, there is provided an end cover assembly, the end cover assembly comprising: an end cover provided with a through hole for injecting an electrolyte and a first engagement portion (the first engagement portion is arranged along the circumferential direction of the through hole and is located on one side of the end cover away from the interior of the battery cell); a seal ring for sealing the through hole; a pressure relief device that covers at least a portion of the seal ring and closes the through-hole, and that is broken when the internal pressure of the battery cell reaches a threshold value to release the blockage of the through-hole and release the internal pressure of the battery cell; The pressure relief device is rotatable and includes a second engagement portion, and when the pressure relief device is rotated to a first position, the second engagement portion engages with the first engagement portion to restrict separation between the pressure relief device and the end cover, and when the pressure relief device is rotated to a second position, the second engagement portion disengages from the first engagement portion to achieve separation between the pressure relief device and the end cover.

[0006] The pressure relief device and the end cover rotate to engage with each other, and the engagement position is located on one side of the end cover away from the inside of the battery cell. This makes it difficult for metal scraps generated when the pressure relief device is attached or detached to fall into the battery cell, reducing the risk of short circuits caused by metal scraps falling into the battery cell and improving the safety of using the battery cell.

[0007] In some embodiments, the pressure relief device includes a main body and a pressure relief member, the main body being connected to the second engagement portion, the pressure relief member closing the through-hole, and the pressure relief member being broken when the internal pressure of the battery cell reaches a threshold value to release the internal pressure.

[0008] In some embodiments, the pressure relief member and the body can be integrated or separate. An integrated structure simplifies the structure and facilitates assembly. Separate structures facilitate the maintenance of the body and the pressure relief member. Alternatively, the body and the pressure relief member can be designed with different materials or structural configurations to meet different application needs.

[0009] In some embodiments, the pressure relief member and the body are provided separately, and the pressure relief member is provided separately between the body and the seal ring. In this case, the pressure relief member is closer to the interior of the housing than when the pressure relief member is not located between the body and the seal ring but is provided at another position, such as above the lower end surface of the body. This allows the gas to impact and break through the pressure relief member more quickly during the pressure relief process, resulting in a more efficient, reliable, and safe pressure relief process.

[0010] In some embodiments, the pressure relief device further includes a split ring disposed between the body portion and the pressure relief member, separating the body portion and the pressure relief member to protect the pressure relief member. The split ring is supported between the body portion and the pressure relief member, separating the body portion and the pressure relief member to prevent direct contact between the body portion and the pressure relief member, thereby reducing or eliminating wear on the pressure relief member during rotation of the body portion and further protecting the pressure relief member.

[0011] In some embodiments, the split ring is attached to the stress relief member, so that the split ring and stress relief member can be pre-assembled before assembly to the end cover assembly, improving assembly efficiency of the battery cells.

[0012] In some embodiments, the stress relief member includes a metal layer and a protective layer, the protective layer is laminated with the metal layer, and the elongation rate of the protective layer is greater than that of the metal layer. Therefore, even if the metal layer is accidentally ruptured, the stress relief member can maintain the closure of the through-holes under the action of the protective layer, thereby reducing the risk of the metal layer being accidentally ruptured and causing problems such as liquid or gas leakage, and effectively improving the reliability of the stress relief member.

[0013] In some embodiments, the pressure relief device includes at least two pressure relief members connected to each other, and when the internal pressure of the battery cell reaches a threshold, the connected portions of the at least two pressure relief members are punched to release the internal pressure. The strength of the connected portions of the pressure relief members is relatively low, which constitutes a weak part of the pressure relief device, and is convenient for meeting the pressure relief needs when the threshold is low.

[0014] In some embodiments, at least two pressure relief members are docked or partially overlapped. When docked, the connected portions of the pressure relief members can have lower strength and thus can meet the pressure relief demands at low thresholds. When overlapped, it is more convenient to implement the connection between each pressure relief member.

[0015] In some embodiments, the at least two pressure relief members partially overlap, with the overlapping portions of the at least two pressure relief members projecting to one side away from the sealing ring relative to the remaining portions of the at least two pressure relief members, which is advantageous in maintaining a flat surface of the pressure relief device near the sealing ring for better contact between the pressure relief device and the sealing ring.

[0016] In some embodiments, the overlapping portions of the at least two stress relief members are folded to reduce the height of the overlapping portions, which is advantageous for reducing the height of the end cover assembly, improving the space utilization rate of the battery cells in the height direction, and increasing the energy density of the battery cells.

[0017] In some embodiments, the split ring of the pressure relief device is provided with a receiving groove, and the overlapping portions of the at least two pressure relief members are received in the receiving groove, thereby preventing the overlapping portions from protruding and causing uneven stress between the main body and the pressure relief members.

[0018] In some embodiments, at least two pressure relief members are connected by heat sealing, which is convenient for operation and allows the strength of the connected parts of the pressure relief members to be lower than the pressure resistance strength of the other parts of the pressure relief members, thereby meeting the explosion-proof requirements of battery cells at lower explosion pressures.

[0019] In some embodiments, the pressure relief member is an aluminum-plastic film, which can utilize the aluminum-plastic film's relatively strong electrolyte penetration prevention and waterproofing capabilities to achieve stable closure of the through-hole under steady state conditions, and can utilize the aluminum-plastic film's superior deformation resistance ability compared to individual metal plates to further reduce the risk of breakage or leakage caused by accidental deformation of the pressure relief member.

[0020] In some embodiments, the first engagement portion is one of the locking groove and the locking post, and the second engagement portion is the other of the locking groove and the locking post. The combination of the locking groove and the locking post achieves a simple structure.

[0021] In some embodiments, the end cover assembly further includes a guide groove, which communicates with the locking groove, and the locking post passes through the guide groove to move in and out of the locking groove during the rotation of the pressure relief device, thereby realizing a smoother and more efficient rotational engagement process under the guiding action of the guide groove.

[0022] In some embodiments, the pressure relief device is provided with a sinking groove, and the sealing ring is positioned in the sinking groove, thereby reducing the space occupied by the sealing ring, which is advantageous for reducing the overall height of the battery cell and improving the energy density of the battery cell.

[0023] According to a second aspect of the present application, the present application provides a housing assembly for use with a battery cell, the housing assembly comprising: a housing that is connected to the end cover to form a battery cell case and that is provided with a through hole and a first engagement portion (the first engagement portion is provided along the circumferential direction of the through hole and is located on one side of the housing away from the interior of the battery cell); a seal ring for sealing the through hole; a pressure relief device configured to cover at least a portion of the sealing ring, close the through-hole, and release the closure on the through-hole when an internal pressure of the housing reaches a threshold value; The pressure relief device is rotatable and includes a second engagement portion, and is configured such that when the pressure relief device is rotated to a first position, the second engagement portion engages with the first engagement portion to limit separation between the pressure relief device and the end cover, and when the pressure relief device is rotated to a second position, the second engagement portion disengages from the first engagement portion to achieve separation between the pressure relief device and the housing.

[0024] The housing has a relatively large free area, which makes it easier to install the through-holes, sealing rings and pressure relief devices.

[0025] According to a third aspect of the present application, the present application provides a battery cell, The battery cell includes an electrode assembly and a case for accommodating the electrode assembly, the case including a housing and an end cover assembly in an embodiment of the present application, the housing having an end opening, and the end cover assembly covering the end opening of the housing; or The battery cell includes an electrode assembly and a case for accommodating the electrode assembly, the case including an end cover and a housing assembly in an embodiment of the present application, the housing having an end opening, and the end cover configured to cover the end opening of the housing.

[0026] Based on the provided end cover assembly and housing assembly, the performance of the battery cell can be effectively improved.

[0027] According to a fourth aspect of the present application, the present application provides a battery, the battery comprising a battery cell according to an embodiment of the present application. The performance of the battery cell is improved, and therefore the performance of the battery is improved.

[0028] According to a fifth aspect of the present application, the present application provides an electrical consumer, the electrical consumer comprising a battery cell according to an embodiment of the present application, the battery cell being used to provide electrical energy, and the performance of the battery cell being improved, thereby improving the performance of the electrical consumer.

[0029] According to a sixth aspect of the present application, the present application provides a method for injecting a liquid into a battery cell, the method comprising: injecting an electrolyte into the interior of the battery cell through a through-hole on the battery cell case housing or end cover; placing the pressure relief device at a second position on the housing or end cover such that the pressure relief device covers at least a portion of the seal ring and a second engagement portion of the pressure relief device is disposed along the circumferential direction of the through-hole on the case and is disengaged from a first engagement portion located on one side of the case away from the interior of the battery cells; and rotating the pressure relief device from the second position to the first position such that the second engagement portion engages with the first engagement portion, limiting separation of the pressure relief device from the housing or end cover.

[0030] Compared to the conventional method of closing the liquid injection hole by laser welding, this liquid injection method not only eliminates the welding sealing process of the liquid injection hole, but also eliminates several processes such as cleaning the welding slag generated by welding and drying the remaining liquid after cleaning. Therefore, the present application improves the manufacturing efficiency of battery cells.

[0031] In some embodiments, the liquid injection method further includes the step of attaching a sealing ring to the case before placing the pressure relief device on the housing or end cover, where the sealing ring can be directly covered after the pressure relief device is attached, or pressure can be applied to the sealing ring to achieve a better sealing effect for the through-hole.

[0032] In some embodiments, the liquid injection method comprises: rotating the pressure relief device from the first position to the second position such that the second engagement portion is disengaged from the first engagement portion; and separating the pressure relief device from the housing or the end cover.

[0033] Removing the pressure relief device from the case makes it convenient to perform maintenance operations such as filling fluid, discharging gas, and replacing the pressure relief device.

[0034] According to a fifth aspect of the present application, the present application provides a liquid injection device for use in a battery cell, the liquid injection device comprising: a liquid injection mechanism configured to inject an electrolyte into the case through a through-hole provided on the case; and a first detachment mechanism that, when the pressure relief device is located in the second position, rotates the pressure relief device from the second position to the first position, changing the second engagement portion of the pressure relief device and the first engagement portion on the case from a disengaged state to an engaged state, thereby limiting separation between the pressure relief device and the housing or end cover of the case.

[0035] The provided liquid injection device can flexibly and conveniently assist in the removal and installation of pressure relief devices during battery cell manufacturing, assembly, secondary liquid injection, and other battery cell maintenance processes. It is simple to operate and is beneficial for improving battery cell assembly efficiency, shortening the maintenance time required for battery cells, and allowing for timely replenishment of liquid when battery cell performance deteriorates, thereby ensuring the working performance of the battery cell. [Brief explanation of the drawings]

[0036] The drawings described herein are provided to facilitate a better understanding of the present application and constitute a part of the present application, and the schematic examples and description thereof are for illustrative purposes only and do not constitute undue limitations on the present application. [Figure 1A] 1 is a schematic diagram of an electrical consumer in accordance with some embodiments of the present disclosure. [Figure 1B] FIG. 1 is a schematic diagram of a battery according to some embodiments of the present disclosure. [Figure 1C] FIG. 1 is a schematic diagram of a battery module according to some embodiments of the present disclosure. [Figure 1D] FIG. 2 is an exploded view of a battery cell according to the first embodiment of the present disclosure. [Figure 2]FIG. 1E is an exploded view of the end cover assembly in FIG. 1D. [Figure 3A] 3 is a perspective view of the end cover assembly when the pressure relief device shown in FIG. 2 is located in a first position. [Figure 3B] 3B is a plan view in which the electrode terminals and insulating members of FIG. 3A are omitted. [Figure 3C] 3C is a cross-sectional view taken along the line AA in FIG. 3B. [Figure 4A] 3 is a perspective view of the end cover assembly when the pressure relief device shown in FIG. 2 is positioned in a second position. [Figure 4B] FIG. 4B is a plan view of FIG. 4A. [Figure 4C] FIG. 4C is a partial schematic view taken along the line BB in FIG. 4B. [Figure 5] FIG. 3 is a perspective view of the end cover in FIG. 2. [Figure 6A] FIG. 3 is a first perspective view of the mounting member shown in FIG. 2. [Figure 6B] FIG. 3 is a second perspective view of the mounting member shown in FIG. 2. [Figure 7A] FIG. 3 is a first perspective view of the pressure relief device shown in FIG. 2. [Figure 7B] FIG. 3 is a second perspective view of the pressure relief device shown in FIG. 2. [Figure 7C] FIG. 3 is a cross-sectional view of the pressure relief device shown in FIG. 2. [Figure 8] FIG. 10 is an exploded view of an end cover assembly according to a second embodiment of the present disclosure. [Figure 9] FIG. 9 is a perspective view of the main body in FIG. 8. [Figure 10A] FIG. 10 is a perspective view of the pressure relief member in FIG. 9. [Figure 10B] 10B is a first modified example of the pressure relief member shown in FIG. 10A. [Figure 10C] 10B is a second modified example of the pressure relief member shown in FIG. 10A. [Figure 11] FIG. 10 is a perspective view of an end cover assembly according to a third embodiment of the present disclosure. [Figure 12] FIG. 12 is an exploded view of the end cover assembly shown in FIG. [Figure 13]FIG. 13 is a combination diagram of the pressure relief member and split ring in FIG. 12. [Figure 14] FIG. 14 is a perspective view of the split ring in FIG. 13. [Figure 15] FIG. 14 is a perspective view of the pressure relief member in FIG. [Figure 16] FIG. 16 is a cross-sectional view of the pressure relief member shown in FIG. [Figure 17] FIG. 17 is an enlarged view of part I in FIG. [Figure 18] 18 is a first modified example of the pressure relief member shown in FIG. [Figure 19] 18 is a second modified example of the pressure relief member shown in FIG. [Figure 20] FIG. 10 is a perspective view of an end cover assembly according to a fourth embodiment of the present disclosure. [Figure 21] FIG. 21 is an exploded view of the end cover assembly shown in FIG. 20. [Figure 22] FIG. 22 is a perspective view of the mounting member in FIG. 21. [Figure 23] FIG. 22 is a perspective view of the pressure relief device in FIG. 21. [Figure 24] FIG. 1 is a perspective view of a case assembly in some embodiments of the present disclosure. [Figure 25] 1 is a schematic flow chart of a method for injecting liquid according to some embodiments of the present disclosure. [Figure 26] 10 is a schematic flow chart of a liquid injection method according to some other embodiments of the present disclosure. [Figure 27] 1 is a schematic diagram of a liquid injection device according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0037] The present application will be described in detail below. In the following paragraphs, different aspects of the embodiments are further defined in detail. Unless expressly indicated as incombinable, each defined aspect can be combined with any other aspect or aspects. In particular, any feature that is considered to be preferred or advantageous can be combined with one or more other preferred or advantageous features.

[0038] Terms such as "first" and "second" used in this application are merely for the convenience of description and are intended to distinguish between different components having the same name, and do not indicate a chronological or subordinate relationship.

[0039] Furthermore, when an element is said to be "on" another element, it may be directly on the other element, or it may be indirectly connected to the other element with one or more intermediate elements interposed therebetween. Furthermore, when an element is said to be "connected" to another element, it may be directly connected to the other element, or it may be indirectly connected to the other element with one or more intermediate elements interposed therebetween. Hereinafter, the same reference numerals refer to the same elements.

[0040] There are several factors that affect the performance of a battery cell, and over the years, those skilled in the art have attempted to improve the structure of battery cells from various aspects in order to improve the performance of battery cells, but have not achieved the expected results.

[0041] A secondary battery cell, such as a lithium-ion battery cell, mainly includes a case, an electrode assembly, an adapter, and an electrolyte. The electrode assembly is placed inside the case and electrically connected to the electrode terminals via the adapter. The electrode terminals are placed in the case and electrically connected to an external circuit. The electrolyte is injected into the housing through a liquid injection hole and undergoes an electrochemical reaction with the active material on the electrode plates of the electrode assembly, resulting in the charge and discharge process.

[0042] To prevent the battery cell from exploding when its internal pressure becomes too high, the battery cell further includes a pressure relief member, which breaks when the internal pressure of the battery cell reaches a threshold, thereby realizing pressure release and fulfilling a safety protection role.

[0043] During the course of implementing this application, the inventors have found that the arrangement of the pressure relief member and the liquid injection hole also affects the performance of the battery cell, including the energy density and service life of the battery cell.

[0044] In the prior art known to the inventors, an exhaust passage and a liquid injection hole corresponding to the pressure relief member are disposed in the end cover. The pressure relief member is fixed to the end cover by laser welding. The liquid injection hole is closed with a separate metal sealing member. After electrolyte injection is completed, the metal sealing member is fixed by laser welding to close the liquid injection hole. This prevents electrolyte leakage during use, which could pollute the surrounding air or environment, or water vapor / metal particles from entering the battery cell, which could cause a short circuit between the positive and negative electrodes.

[0045] In the above arrangement, the pressure relief member is fixed by welding, so it can only be used once. Once broken, the battery cell structure will be irreversibly damaged, and the entire battery cell will be discarded, which will affect the service life of the battery cell.

[0046] However, in the above-described arrangement, the liquid injection hole is sealed by welding, making it difficult to realize the function of refilling the electrolyte during battery cell use and meeting the liquid replenishment needs of the battery cell. After several charge / discharge cycles, the internal electrolyte of the battery cell inevitably reacts irreversibly and is consumed, reducing the usable capacity of the battery cell and shortening the battery cell's service life. If the internal electrolyte of the battery cell could be replenished during battery cell use, the decrease in battery cell capacity could be effectively alleviated and the service life of the battery cell could be improved. However, if the liquid injection hole is sealed by welding, the liquid injection must be completed during the manufacturing process. This is because refilling the liquid during battery cell use would destroy the laser-welded structure, which would cause irreversible damage to the battery cell structure and lead to the battery cell being discarded.

[0047] Furthermore, in the above-mentioned arrangement, the liquid injection hole and the exhaust passage are separately arranged, which takes up a relatively large space and affects the energy density of the battery cell.

[0048] In light of the above, the present application improves the arrangement of the pressure relief member and the liquid injection hole, i.e., the pressure relief member is detachably arranged, and the exhaust passage corresponding to the pressure relief member is also used as the liquid injection hole, thereby forming an integrated structure for pressure relief and liquid injection, which extends the service life of the battery cell, improves the energy density of the battery cell, and enhances the performance of the battery cell.

[0049] To achieve the above object, the present application provides an end cover assembly, a housing assembly, a battery cell, a battery, an electrical consumer device, a liquid injection method, and a liquid injection device.

[0050] 1A to 27 show the structures of an electrical consumer device, a battery, a battery cell, an end cover assembly, a housing assembly, and a liquid injection device and a process of a liquid injection method according to some embodiments of the present application.

[0051] For ease of explanation, the directions of the battery cell will be defined using the coordinate system of FIG. 1D . Here, the X-axis indicates the longitudinal direction of the battery cell 400. The Y-axis is perpendicular to the X-axis in a horizontal plane and indicates the width direction of the battery cell 400. The Z-axis is perpendicular to the plane formed by the X-axis and Y-axis and indicates the height direction of the battery cell 400. Based on these orientation definitions, the orientations or positional relationships have been described using terms such as "upper," "lower," "top portion," "bottom portion," "front," "rear," "inner," and "outer." However, such orientation definitions are intended to facilitate the explanation of the present application and do not indicate or imply that the referred-to device must have a specific orientation, be configured, or operate in a specific orientation, and should not be construed as limiting the present application.

[0052] Next, the present application will be explained in conjunction with FIGS. 1A to 27.

[0053] 1A illustrates the structure of an electricity consuming device 100 in some embodiments. Referring to FIG. 1A, the electricity consuming device 100 is a device that uses a battery cell 400 as a power source and includes the battery cell 400 for providing electrical energy.

[0054] Here, the electricity consuming equipment 100 may be a mobile equipment such as a vehicle 101, a boat, a small airplane, etc., and includes a power source including a battery cell 400, which provides driving force for the electricity consuming equipment 100. In some embodiments, the driving force of the electricity consuming equipment 100 is entirely electric energy, in which case the power source includes only the battery cell 400. In other embodiments, the driving force of the electricity consuming equipment 100 includes electric energy and other energy (e.g., mechanical energy), in which case the power source includes the battery cell 400 and other equipment such as an engine.

[0055] Take for example a case where the electric consumer 100 is a vehicle 101. Referring to Figure 1A, in some embodiments, the electric consumer 100 is a new energy vehicle such as a pure electric vehicle, a hybrid vehicle, or an extended range electric vehicle, and the electric consumer 100 includes a battery cell 400, a controller 104, and a powered device 102 such as a motor 103, and the battery cell 400 is electrically connected to the powered device 102 such as the motor 103 via the controller 104 so that the battery cell 400 supplies electricity to the powered device 102 such as the motor 103 under the control of the controller 104.

[0056] In order for the battery cells to achieve a relatively high output to meet higher usage demands, the battery 200 can be arranged in the electricity consuming equipment 100. Referring to Figures 1B and 1C, the battery 200 includes at least two battery cells 400 and provides more electrical energy than when a single battery cell 400 is arranged.

[0057] 1B and 1C, in some embodiments, the battery 200 includes a housing 500 and a plurality of battery cells 400, which are disposed inside the housing 500. The plurality of battery cells 400 may be formed into a battery module 300, and then the battery 200 may be formed from the plurality of battery modules 300.

[0058] 1B , in some embodiments, the housing 500 includes a first housing 501 and a second housing 502. The first housing 501 and the second housing 502 are interlocked with each other to form a closed space inside the housing 500 to accommodate the battery cells 400.

[0059] 1B and 1C, in some embodiments, the number of battery cells 400 is large, and the battery cells 400 are arranged in groups, with each group of battery cells 400 being referred to as a battery module 300. In other words, the battery 200 includes at least two battery modules 300, all of which are arranged in a housing 500, and each battery module 300 includes at least two battery cells 400. It should be noted that FIG. 1B employs a simplified depiction of the battery modules 300, and FIG. 1C employs a simplified depiction of the battery cells 400 of the battery module 300.

[0060] The battery cells 400 of the battery module 300 are electrically connected in series, parallel, or a mixed connection to achieve a relatively large capacity or output. For example, referring to FIG. 1C , in some embodiments, the battery cells 400 are arranged upright, in which the height direction of the battery cells 400 coincides with the vertical direction, and the battery cells 400 of the battery module 300 are arranged side by side along the width direction of the battery cells 400. Also, for example, in some other embodiments, the battery cells 400 are arranged horizontally, in which the width direction of the battery cells 400 coincides with the vertical direction, and each battery cell 400 of the battery module 300 includes at least one layer overlapping along the width direction of the battery cells 400, with each layer including at least two battery cells 400 spaced apart along the length direction.

[0061] It can be seen that the battery cells 400 are all core structures of the electricity consuming device 100 and the battery 200, and the performance of the battery cells 400 directly affects the performance of the electricity consuming device 100 and the battery 200. Extending the lifespan and improving the performance of the battery cells 400 is beneficial for extending the lifespan and improving the performance of the electricity consuming device 100 and the battery 200.

[0062] Next, the structure of the battery cell 400 will be described with reference to FIGS. 1D to 24. FIG.

[0063] 1D shows the overall structure of a battery cell 400 according to some embodiments. Referring to FIG. 1D, the battery cell 400 can be any type of battery cell, such as a rectangular battery cell or a cylindrical battery cell, and includes a case 70, an electrode assembly 30, a separator 40, an adapter 20, and the like.

[0064] Here, the case 70 accommodates the electrode assembly 30 and other components to protect them. The case 70 includes a housing 7 and an end cover assembly 10. The housing 7 has an end opening 71. The end cover assembly 10 covers the end opening 71 of the housing 7 to form an airtight space inside the case 70 for accommodating the electrode assembly 30 and other components.

[0065] The electrode assembly 30 is used to generate electrical energy and is arranged in a case 70. It is formed by stacking or winding together a first electrode plate, a second electrode plate, and an insulating spacer between the first and second electrode plates. One of the first and second electrode plates is a positive electrode plate, and the other is a negative electrode plate. Both have a coating portion coated with an active material and a tab 301 extending outward from the coating portion without the active material. Electrical energy generated by the electrode assembly 30 is transmitted to the outside via the tab 301. Here, the tab 301 corresponding to the positive electrode plate can be referred to as a positive electrode tab, and the tab 301 corresponding to the negative electrode plate can be referred to as a negative electrode tab. The positive electrode tab extends from the coating portion of the positive electrode plate, and the negative electrode tab extends from the coating portion of the negative electrode plate. In some cases, for example, in some rectangular battery cells, the positive electrode tab and the negative electrode tab are located at the same end of the electrode assembly 30. In other cases, for example, in some circumferential battery cells, the positive and negative tabs are located at opposite ends of the electrode assembly 30.

[0066] According to actual usage demands, the number of electrode assemblies 30 in the battery cell 400 may be one, two, or more.

[0067] The separator 40 is disposed in the case 70 and is positioned between the electrode assembly 30 and the housing 7 to insulate the electrode assembly 30 from the housing 7 and prevent a short circuit from occurring between the electrode assembly 30 and the housing 7.

[0068] The adapter 20 is provided in the case 70 and is positioned between the electrode assembly 30 and the end cover assembly 10. The adapter 20 is used to establish an electrical connection between the electrode assembly 30 and the electrode terminals 10c of the end cover assembly 10. Specifically, referring to FIGS. 1D and 2, in some embodiments, the end cover assembly 10 includes two electrode terminals 10c, which correspond to a positive tab and a negative tab, respectively, and can be referred to as a positive terminal and a negative terminal, respectively. In this case, the battery cell 400 includes two adapters 20, which correspond one-to-one to the two electrode terminals 10c and are used to establish an electrical connection between the positive terminal and the positive tab, and an electrical connection between the negative terminal and the negative tab, respectively. As a variation, in some other embodiments, the end cover assembly 10 may include only one electrode terminal 10c, but the battery cell 400 includes two end cover assemblies 10, which are disposed on opposite sides of the electrode assembly 30.

[0069] 2 to 23 show more specific structures of the end cover assembly 10 in some embodiments. Next, the structure of the end cover assembly 10 will be further introduced by combining FIGS.

[0070] 2 to 23, in some embodiments, the end cover assembly 10 includes an end cover 10a, an insulating member 10d, a seal ring 3, and a pressure relief device 10b.

[0071] The end cover 10a is used to cover the end opening 71 of the housing 7 and provides a mounting base for other structural components of the end cover assembly 10, such as the electrode terminals 10c and pressure relief devices 10b. Through holes 11 for injecting electrolyte are arranged on the end cover 10a. The through holes 11 penetrate both opposing surfaces of the end cover 10a so that electrolyte can be injected into the battery cells 400 through the through holes 11. The shape of the through holes 11 is not limited and may be, for example, a circular hole, an elliptical hole, a polygonal hole, or a hole of another shape.

[0072] The insulating member 10d is provided between the end cover 10a and the electrode assembly 30 to provide insulation between the end cover 10a and the electrode assembly 30.

[0073] The seal ring 3 is provided on the end cover 10a to seal the through hole 11 and prevent leakage of the electrolyte.

[0074] The pressure relief device 10b is disposed on the end cover 10a, covers at least a portion of the seal ring 3, and closes the through-hole 11. When the internal pressure of the battery cell 400 reaches a threshold, the pressure relief device 10b is broken and releases the blockage of the through-hole 11, thereby releasing the internal pressure of the battery cell 400 and fulfilling a safety and explosion-proof role.

[0075] Here, the threshold value may vary depending on one or various materials of the positive electrode plate, negative electrode plate, electrolyte, and insulating spacer of the battery cell 400, and the specific size may also vary depending on design needs.

[0076] Destruction of the pressure relief device 10b means that the pressure relief device 10b operates or is activated to a certain state (e.g., at least a portion of the pressure relief device 10b bursts, crushes, breaks, or opens, etc.) to relieve the internal pressure and temperature of the battery cell 400.

[0077] When the internal pressure or temperature of the battery cell 400 reaches a set threshold, the pressure relief device 10b operates or a vulnerable portion of the pressure relief device 10b is destroyed, forming an opening or passage for relieving the internal pressure or temperature. The pressure relief device 10b may have a structural form such as an explosion-proof valve, a gas valve, a decompression valve, or a safety valve, and more specifically, may use a pressure-sensing or temperature-sensing element or structure. After the pressure relief device 10b is destroyed, high-temperature and high-pressure materials within the battery cell 400 are discharged as waste from the destroyed portion of the pressure relief device 10b to the outside, and by performing pressure relief and temperature relief of the battery cell 400 in a situation where pressure or temperature control is possible, the occurrence of a potentially more serious accident is prevented.

[0078] Based on the above arrangement, an integrated pressure relief and liquid injection structure is formed on the end cover assembly 10. The through-hole 11 is used as both a liquid injection hole and an exhaust passage, thereby combining the functions of liquid injection and gas discharge, eliminating the need for separate liquid injection holes and exhaust passages, effectively reducing space occupation and improving the energy density of the battery cell 400. Meanwhile, the pressure relief device 10b is used both as an explosion-proof device and as a sealing member for the liquid injection hole, combining the explosion-proof pressure relief function and the liquid injection sealing function, eliminating the need for a separate metal sealing member for the liquid injection hole, which is advantageous in simplifying the structure of the battery cell 400.

[0079] To facilitate removal of the pressure relief device 10b and extend the service life of the battery cell 400, in some embodiments, the pressure relief device 10b and the end cover 10a can be configured to rotate in engagement.

[0080] 2 to 23, first engagement portions 24 are provided on the end cover 10a, and the first engagement portions 24 are arranged along the circumferential direction of the through-holes 11. Meanwhile, the pressure relief device 10b is rotatable and includes second engagement portions 42 that mate with the first engagement portions 24. When the pressure relief device 10b rotates to the first position, the second engagement portions 42 engage with the first engagement portions 24, limiting separation between the pressure relief device 10b and the end cover 10a. When the pressure relief device 10b rotates to the second position, the second engagement portions 42 disengage from the first engagement portions 24, enabling separation between the pressure relief device 10b and the end cover 10a. Specifically, in some embodiments, the pressure relief device 10b rotates relative to the end cover 10a in a plane perpendicular to the height direction of the battery cells 400, and the rotation axis is the axis of the through-holes 11.

[0081] Based on the above arrangement, when the pressure relief device 10b is controlled to rotate between the first position and the second position relative to the end cover 10a, the pressure relief device 10b can be attached or detached by utilizing the engagement or disengagement between the first engagement portion 24 and the second engagement portion 42 to connect or separate the pressure relief device 10b and the end cover 10a.

[0082] When the pressure relief device 10b rotates to the first position relative to the end cover 10a and the first engaging portion 24 engages with the second engaging portion 42, the pressure relief device 10b is coupled to the end cover 10a. The pressure relief device 10b is stably fixed on the end cover 10a, and the through-holes 11 are blocked to prevent liquid leakage, gas leakage, or external impurities from entering the battery cells 400. In this case, the pressure relief device 10b is prevented from moving away from the electrode assembly 30 relative to the end cover 10a due to the restriction of the end cover 10a, preventing the pressure relief device 10b from detaching from the end cover 10a. In some embodiments, the pressure relief device 10b in the first position presses the seal ring 3, increasing its deformation and thereby achieving a better sealing effect. In other embodiments, the pressure relief device 10b in the first position does not press the seal ring 3 but simply contacts it, limiting its vertical movement.

[0083] When the pressure relief device 10b is rotated to a second position relative to the end cover 10a and the first engagement portion 24 and the second engagement portion 42 are disengaged, the end cover 10a does not restrict the pressure relief device 10b from moving to one side away from the electrode assembly 30, and therefore the pressure relief device 10b can be removed from the end cover 10a.

[0084] Removing the pressure relief device 10b not only facilitates replacement of a pressure relief device 10b that has been damaged or has prematurely creeped to a threshold value and is therefore no longer able to withstand damage, but also reduces the lifespan requirements of the pressure relief device 10b and improves its reliability. At the same time, the pressure relief device 10b unblocks the through-hole 11, allowing the through-hole 11 to communicate with the inside and outside of the battery cell 400. In this case, on the one hand, additional electrolyte can be injected into the battery cell 400 through the through-hole 11, thereby realizing a secondary liquid injection function. This allows the battery cell 400 to be replenished or replaced with electrolyte conveniently and timely during use, effectively alleviating capacity loss and extending the service life of the battery cell 400. On the other hand, gas inside the battery cell 400 can also be discharged through the through-hole 11, realizing a gas discharge process.

[0085] Here, the gas inside the battery cell 400 that is discharged through the through-holes 11 may include gas generated during use of the battery cell 400. Discharging the gas generated during use of the battery cell 400 can relieve the internal pressure of the case 70, and the continuous gas generation acts on the pressure relief device 10b, preventing premature creep of the pressure relief device 10b. This premature creep of the pressure relief device 10b prevents leakage of the battery cell 400 or intrusion of water / gas, which is advantageous to extending the service life of the pressure relief device 10b and further advantageous to extending the service life of the battery cell 400. Meanwhile, discharging the gas generated inside the case 70 can reduce the force that the expansion of the battery cell 400 applies to other structures, preventing structural damage to other structures due to excessive expansion of the battery cell 400, which is advantageous to further improve the service life of the battery 200 and the electrical consumption equipment 100 that use the battery cell 400.

[0086] Based on the above configuration, the pressure relief device 10b can be removed after a certain period of use, and the gas inside the battery cell 400 can be discharged, thereby reducing the requirements for the service life of the pressure relief device 10b and improving the service reliability of the pressure relief device 10b. In addition, after removing the pressure relief device 10b, secondary liquid can be replenished, improving the performance of the battery cell 400 and extending the service life of the battery cell 400. Meanwhile, when the pressure relief device 10b is reinstalled, it can be replaced with a new pressure relief device 10b, further improving the service reliability of the battery cell 400 and extending the service life of the battery cell 400.

[0087] The above-described arrangement allows the pressure relief device 10b to be detachably mounted, allowing for quick and easy installation and removal without causing irreversible damage to the battery cells 400. This allows for repeated use of the battery cells 400 and extends their service life. Furthermore, liquid injection and gas discharge can be performed during the installation and removal of the pressure relief device 10b, improving the reliability of the battery cells 400 and extending their service life. Furthermore, the space in the end cover 10a can be utilized more efficiently, reducing the space required for a single liquid injection hole and improving the energy density of the battery cells 400. At the same time, because the passage area of ​​the exhaust passage is generally larger than the area of ​​the liquid injection hole, using the through-holes 11 used for gas discharge as liquid injection holes simultaneously increases the liquid injection area, improving liquid injection efficiency, and accelerating production and improving production capacity.

[0088] Therefore, when the pressure relief device 10b is configured to be rotationally locked and the gas discharge through-hole 11 corresponding to the pressure relief device 10b is also used as a liquid injection hole, the pressure relief device 10b can be quickly attached and detached, and liquid injection and gas discharge can be facilitated, while preventing irreversible damage to the battery cell 400. This can effectively improve the energy density of the battery cell 400, extend the service life of the battery cell 400, and improve the performance of the battery cell 400.

[0089] The detachable pressure relief device 10b can be easily removed to replace the pressure relief device 10b when necessary, for example, if it is already broken or if it has operated for a predetermined period of time without being broken. This facilitates battery cell maintenance operations such as liquid injection and gas discharge. Furthermore, removing the pressure relief device 10b does not cause irreversible damage to the battery cell 400, and the appearance of the battery cell 400 can be maintained intact before and after removal, without affecting its use after liquid injection or gas discharge. At the same time, after liquid injection and gas discharge are completed, the pressure relief device 10b can be easily attached to the end cover 10a to reliably close the through-hole 11, ensuring the reliability of the battery cell 400 after liquid injection and gas discharge. Furthermore, because the through-hole 11 is closed directly by rotating the pressure relief device 10b, there is no need to seal the through-hole 11 through laser welding. This eliminates the need for a cleaning process for the through-hole 11 before laser welding, thereby improving the manufacturing efficiency of the battery cell 400.

[0090] To achieve detachable placement of the pressure relief device 10b, the pressure relief device 10b can be connected to the end cover 10a using other methods, such as a screw connection. However, using a rotational engagement method places less demand on the fitting accuracy between the pressure relief device 10b and the end cover 10a, is easier to process, and is simpler and more convenient to operate, which is advantageous for achieving a more efficient attachment and detachment process. This improves the assembly efficiency of the battery cells 400 during manufacturing and reduces the maintenance time during use of the battery cells 400. Furthermore, because the rotational engagement method does not require a large number of threads like a screw connection, it does not require as much height space as a screw connection. Therefore, the height requirement for the end cover assembly 10 is relatively low, which reduces the height of the battery cells 400, improves the utilization rate of the height space of the battery cells 400, and is advantageous for increasing the energy density of the battery cells 400.

[0091] Furthermore, when using a screw connection method, metal scraps generated by friction during the process of tightening or loosening the screw members may fall directly into the battery cell 400, which may cause a short circuit inside the battery cell 400. When using a rotation engagement method, a rotation engagement structure can be set up to reduce the risk of a short circuit caused by falling metal scraps.

[0092] 2 to 23, in some embodiments, the first engagement portion 24 is located on one side of the end cover 10a away from the interior of the battery cell 400 (i.e., one side away from the housing 7, i.e., one side away from the electrode assembly 30). In other words, the first engagement portion 24 is not located directly on the surface of the end cover 10a facing the interior of the battery cell 400 (which is also the surface of the end cover 10a closer to the electrode assembly 30), but is located at a predetermined distance from the surface of the end cover 10a facing the interior of the battery cell 400. Here, the size of the "predetermined distance" is not specifically limited, and for example, the first engagement portion 24 may be located in an upper region, a middle region, or a lower region of the end cover 10a so that at least a portion of the end cover 10a is located between the first engagement portion 24 and the electrode assembly 30.

[0093] During the rotation of the pressure relief device 10b, friction may occur between the first engaging portion 24 and the second engaging portion 42, generating metal particles. By providing the first engaging portion 24 on one side of the end cover 10a away from the inside of the battery cell 400, it is possible to prevent metal particles generated during the rotation from falling directly into the housing 7 and causing a short circuit in the battery cell 400, thereby effectively improving the operational safety of the battery cell 400.

[0094] 2 to 4C, in some embodiments, the position of the first engagement portion 24 is not lower in the height direction than the position of the seal ring 3, and therefore the rotational engagement position is not lower than the position of the seal surface, so that metal scrap generated during the rotational friction process is blocked by the seal ring 3 and does not fall into the housing 7. After the pressure relief device 10b is removed, the metal scrap can be easily cleaned and the falling of metal scrap can be more reliably prevented. On the other hand, if the rotational engagement position is not lower than the position of the seal surface, it is convenient for the pressure relief device 10b to apply force to the seal ring 3 during the rotation process, which increases the deformation of the seal ring 3 and improves the sealing effect of the seal ring 3.

[0095] 4C, in some embodiments, a sinking groove 412 is provided on the pressure relief device 10b, and the sealing ring 3 is provided in the sinking groove 412. Therefore, the height occupation of the sealing ring 3 can be reduced, which further reduces the overall height of the end cover assembly 10 and improves the energy density of the battery cell 400.

[0096] Next, the structure of the pressure relief device 10b will be further explained.

[0097] 2 to 23, in some embodiments, the pressure relief device 10b includes a main body 4 and a pressure relief member 5, the main body 4 is connected to the second engagement portion 42, the pressure relief member 5 closes the through-hole 11, and the pressure relief member breaks to relieve the internal pressure when the internal pressure of the battery cell 400 reaches a threshold value. Therefore, the main body 4 can be used to drive and rotate the second engagement portion 42, thereby realizing the rotation locking function, and the pressure relief member 5 can be used to realise the pressure relief function.

[0098] 2-7C and 20-23, the main body 4 and the pressure relief member 5 can be provided as a single unit to simplify the structure and facilitate assembly. Alternatively, as shown in FIGS. 8-19, the main body 4 and the pressure relief member 5 can be provided separately. This facilitates maintenance of the main body 4 and the pressure relief member 5. For example, if the pressure relief member 5 is damaged but the main body 4 is not, only the pressure relief member 5 can be replaced, reducing maintenance costs. At the same time, the main body 4 and the pressure relief member 5 can be designed with different materials or structural configurations to meet different usage needs. For example, the thickness of the pressure relief member 5 can be flexibly changed to achieve blast pressure relief at different thresholds by adjusting the internal pressure capacity of the pressure relief member 5.

[0099] 8 to 19 , when the body 4 and the pressure relief member 5 are provided separately, the pressure relief member 5 can be disposed between the body 4 and the seal ring 3. In this case, the pressure relief member 5 is closer to the interior of the housing 7 than when the pressure relief member 5 is disposed not between the body 4 and the seal ring 3 but at another location, such as above the lower end surface of the body 4. This allows the gas to impact and break through the pressure relief member 5 more quickly during pressure relief, resulting in a more efficient and secure pressure relief process. Furthermore, the pressure relief member 5 disposed between the body 4 and the seal ring 3 can cover the seal ring 3. The pressure relief member 5 can be configured to have a larger cross-sectional area than the body 4, allowing the pressure relief device 10b to cover the seal ring 3 via the pressure relief member 5 rather than the body 4. This allows for more complete contact between the pressure relief device 10b and the seal ring 3 and more secure crimping and / or positioning relative to the seal ring 3.

[0100] Continuing with reference to Figures 8 to 19, when the pressure relief member 5 is located between the main body portion 4 and the sealing ring 3, in some embodiments, the pressure relief device 10b further includes a split ring 6, which is disposed between the main body portion 4 and the pressure relief member 5 to separate the main body portion 4 and the pressure relief member 5 and protect the pressure relief member 5.

[0101] Because the split ring 6 is supported between the main body 4 and the pressure relief member 5, it separates the main body 4 and the pressure relief member 5 so that they do not come into direct contact with each other, thereby reducing or eliminating wear on the pressure relief member 5 during the rotation of the main body 4 and also protecting the pressure relief member 5. Meanwhile, because the middle part of the split ring 6 is hollow, clogging of the liquid injection passage and the exhaust passage does not occur, which is advantageous for smooth liquid injection and gas exhaust processes.

[0102] Here, the split ring 6 can be attached to the pressure relief member 5; for example, the split ring 6 can be glued to the pressure relief member 5 or connected via a connecting member. Therefore, the split ring 6 and the pressure relief member 5 can be pre-assembled before assembling them to the end cover 10a, thereby improving the assembly efficiency of the battery cell 400.

[0103] The construction of the pressure relief member 5 can vary.

[0104] As one example, the stress relief member 5 may be a single-layer member. For example, referring to Figures 2 to 7C, 8 to 10A, and 20 to 23, in some embodiments, the stress relief member 5 includes only a metal layer 51. In this case, the structure of the stress relief member 5 is relatively simple.

[0105] Alternatively, the stress relief member 5 may have a two-layer structure or a multi-layer structure. For example, referring to Figures 10B, 10C, 17, and 19, in some embodiments, the stress relief member 5 includes a metal layer 51 and a protective layer 52a, where the protective layer 52a and the metal layer 51 are stacked, and the elongation of the protective layer 52a is greater than that of the metal layer 51. Therefore, even if the metal layer 51 is accidentally ruptured, the stress relief member 5 maintains the closure of the through-hole 11 under the action of the protective layer 52a, thereby reducing the risk of the metal layer 51 being accidentally ruptured and causing problems with liquid and gas leakage, and effectively improving the reliability of the stress relief member 5.

[0106] Specifically, the protective layer 52a may have a single-layer structure, be disposed on one side of the metal layer 51 closer to the electrode assembly 30, or be disposed on one side of the metal layer 51 farther from the electrode assembly 30. Alternatively, the protective layer 52a may have a two-layer structure or a multi-layer structure to more fully protect the metal layer 51. For example, referring to FIGS. 10B and 10C , in some embodiments, the protective layer 52a includes a first protective layer 521 and a second protective layer 523, where the first protective layer 521 is disposed on one side of the metal layer 51 farther from the electrode assembly 30 and the second protective layer 523 is disposed on one side of the metal layer 51 closer to the electrode assembly 30. In this case, the first protective layer 521 and the second protective layer 523 sandwich the metal layer 51 therebetween, and the metal layer 51 is located inside the protective layer 52a. Therefore, the protective layer 52a can provide double protection to the metal layer 51 on both sides in the thickness direction of the metal layer 51, which has a better protective effect and can reliably reduce the risk of accidental liquid and gas leakage.

[0107] In one specific embodiment of the multilayer pressure relief member 5, the pressure relief member 5 may be an aluminum-plastic film 52. The aluminum-plastic film 52 has a multilayer thin film structure and generally includes an outer shielding layer, a barrier layer, and a high-blocking layer, arranged in this order from outside to inside, with adhesive between each layer. Here, the outer shielding layer, also known as a base layer, is primarily made of nylon or PET (Polyethylene terephthalate) material and serves to protect the barrier layer from damage. The barrier layer is generally an aluminum layer and serves to provide shaping and waterproofing. The high-blocking layer, also known as an electrolyte-resistant layer, is primarily made of polypropylene material. Because the aluminum-plastic film 52 has multiple advantages, such as high shielding properties, insulation properties, and electrolyte resistance, it is used in related art as one of the core materials for packaging soft-pack battery cells and serves to protect the internal electrode assembly 30. The present application breaks away from the conventional method of using the aluminum-plastic film 52 and uses the aluminum-plastic film 52 as the pressure relief member 5. Specifically, the outer blocking layer, barrier layer, and high-blocking layer of the aluminum-plastic film 52 are used as the first protective layer 521, metal layer 522, and second protective layer 523, respectively. This utilizes the aluminum-plastic film 52's relatively strong electrolyte penetration prevention and waterproofing capabilities to achieve stable closure of the through-hole 11 under steady state conditions. Furthermore, the aluminum-plastic film 52's superior deformation resistance ability compared to individual metal plates can be utilized to further reduce the risk of breakage or leakage caused by accidental deformation of the pressure relief member 5.

[0108] The number of pressure relief members 5 is not limited and may be one, two, or more. Referring to FIGS. 11 to 19, when the pressure relief device 10b includes at least two pressure relief members 5, the at least two pressure relief members 5 can be connected to each other, and when the internal pressure of the battery cell 400 reaches a threshold, the connected portions of the at least two pressure relief members 5 are punched out to release the internal pressure. In this case, the strength of the connected portions of the pressure relief members 5 is relatively low, forming a weak portion of the pressure relief device 10b and making it easy to meet the pressure relief demand when the threshold is low.

[0109] 19, in some embodiments, the at least two pressure relief members 5 can be docked, i.e., connected without overlapping, in which case the connected portions of the pressure relief members 5 can have lower strength to meet the pressure relief demands at low thresholds.

[0110] 17 and 18, in some other embodiments, the at least two pressure relief members 5 are docked or partially overlapped, which makes it more convenient to implement the connection between each pressure relief member 5.

[0111] 17-18, in some embodiments, when at least two pressure relief members 5 partially overlap, the overlapping portions 524 of the at least two pressure relief members 5 protrude to one side, away from the sealing ring 3, relative to the remaining portions of the at least two pressure relief members 5. This is advantageous in keeping the surface of the pressure relief device 10b near the sealing ring 3 flat, so as to provide better contact between the pressure relief device 10b and the sealing ring 3.

[0112] 17 , in some embodiments, the overlapping portion 524 is bent, specifically, the overlapping portion 524 is bent toward the side closer to the seal ring 3. Therefore, the height of the overlapping portion 524 can be reduced. The reduction in the height of the overlapping portion 524 is advantageous in reducing the height of the end cover assembly 10, improving the space utilization rate of the battery cells 400 in the height direction, and increasing the energy density of the battery cells 400.

[0113] 13 to 15, in some embodiments, when the pressure relief device 10b includes a split ring 6, an accommodation groove 61 is provided on the split ring 6, and the overlapping portion 524 is accommodated in the accommodation groove 61. This prevents the overlapping portion 524 from protruding and causing uneven stress between the main body 4 and the pressure relief member 5.

[0114] In the above-described embodiments, various connection methods, such as bonding or heat sealing, can be used between the pressure relief members 5. Here, when the heat sealing method is used for connection, the operation is convenient, and the strength of the connected portions of the pressure relief members 5 can be set lower than the pressure resistance strength of the remaining portions of the pressure relief members, thereby meeting the explosion-proof requirements of battery cells at lower explosion pressures.

[0115] Furthermore, based on the above-described embodiments, a notch 53 can be further provided on the pressure relief member 5. The notch 53 forms a weak area of ​​the pressure relief member 5, and when the internal pressure of the battery cell 400 reaches a threshold, the pressure relief member 5 will first break at the position of the notch 53, making it less likely to break the pressure relief member 5, realizing directional gas discharge pressure relief for the battery cell 400, and further improving the safety of the battery cell 400 in use.

[0116] Here, the notch 53 may have various shapes, such as a cross-shaped groove 532 or an annular groove 531. Furthermore, when the notch 53 is an annular groove 531, the annular groove 531 may be a complete or incomplete circular groove. For example, in some embodiments, when the annular groove 531 is a 3 / 4 circular groove, when the notch 53 is broken through, it does not completely separate from the rest of the pressure relief member 5 but still maintains a connection with the rest of the pressure relief member 5. This prevents the notch 53 from popping out directly and causing other damage, and improves the safety of the pressure relief process.

[0117] 4C , in some embodiments, the notch 53 is located radially inside the inner ring of the sealing ring 3. In other words, it is located radially of the sealing ring 3, with the edge of the notch 53 located inside the inner ring of the sealing ring 3 and not extending beyond the inner ring of the sealing ring 3. In this case, the notch 53 is not subjected to the repulsive force of the sealing ring 3, which prevents the notch 53 from accidentally bursting due to the repulsive force of the sealing ring 3. This is advantageous for improving the reliability of the pressure relief member 5 and extending the service life of the pressure relief member 5.

[0118] Next, the structure of the rotational engagement between the pressure relief device 10b and the end cover 10a will be further introduced.

[0119] As described above, the pressure relief device 10b and the end cover 10a achieve rotational engagement by coupling the first engagement portion 24 on the end cover 10a with the second engagement portion 42 on the pressure relief device 10b. Here, when one of the first engagement portion 24 and the second engagement portion 42 is the locking groove 24a, the other is the locking post 42a. In other words, when the first engagement portion 24 is one of the locking groove 24a and the locking post 42a, the second engagement portion 42 is the other of the locking groove 24a and the locking post 42a. For example, referring to FIGS. 2 to 23, in some embodiments, the first engagement portion 24 is the locking groove 24a and the second engagement portion 42 is the locking post 42a, which makes it easier to process the locking groove 24a and the locking post 42a.

[0120] 2 to 23, in some embodiments, the end cover assembly 10 further includes a guide groove 25, which communicates with the locking groove 24a, such that the locking post 42a moves in and out of the locking groove 24a through the guide groove 25 during rotation of the pressure relief device 10b. Therefore, on the one hand, the guide groove 25 avoids the pressure relief device 10b in the second position to prevent interference between the pressure relief device 10b and the end cover 10a. On the other hand, the guide groove 25 guides the locking post 42a to move in and out of the locking groove 24a more smoothly during rotation of the pressure relief device 10b, thereby achieving a smoother and more efficient rotational engagement process.

[0121] 2 to 23, in some embodiments, the end cover 10a not only includes an end cover body 1 but also a mounting member 2 so that the first engagement portion 24 can be easily positioned on the end cover 10a. The end cover body 1 has an end opening 71 for covering the housing 7. The mounting member 2 is positioned on the end cover body 1, specifically on one side of the end cover body 1 away from the electrode assembly 30, with a gap between the surface of the end cover body 1 facing the electrode assembly 30. The through-hole 11 sequentially penetrates the mounting member 2 and the end cover body 1 and includes a first hole segment 111 located on the end cover body 1 and a second hole segment 26 located on the mounting member 2. The first hole segment 111 and the second hole segment 26 are sequentially positioned from the inside to the outside of the battery cell 400 and penetrate each other. When an electrolyte is injected, the electrolyte flows into the housing 7 by sequentially passing through the second hole segment 26 and the first hole segment 111. The first engagement portion 24 is disposed on the mounting member 2, or the first engagement portion 24 is formed by being surrounded by the mounting member 2 and the end cover main body 1.

[0122] Because the thickness of the end cover body 1 is generally thin, it is difficult to directly process the first engagement portions 24 on the end cover body 1. By installing more mounting members 2 connected to the end cover body 1 and arranging the first engagement portions 24 on the mounting members 2, or by arranging the first engagement portions 24 between the mounting members 2 and the end cover body 1, the difficulty of processing the first engagement portions 24 can be effectively reduced, and the arrangement of the first engagement portions 24 on the end cover 10a can be easily achieved.

[0123] Specifically, referring to FIGS. 2 to 19, in some embodiments, the body 4 of the pressure relief device 10b is inserted into the second hole segment 26, the first engagement portion 24 is disposed on the inner wall of the mounting member 2, and the second engagement portion 42 is disposed on the outer wall of the body 41. Alternatively, referring to FIGS. 20 to 23, in other embodiments, the body 4 is attached to a sleeve on the outside of the mounting member 2, the first engagement portion 24 is attached to the outer wall of the mounting member 2, and the second engagement portion 42 is attached to the inner wall of the body 41. In these two cases, the first engagement portion 24 and the second engagement portion 42 can both be engaged or disengaged by rotating the pressure relief device 10b, allowing the pressure relief device 10b to be attached to or detached from the end cover 10a. Here, inserting the body 4 into the second hole segment 26 is advantageous in reducing the height of the pressure relief device 10b protruding from the end cover 10a, thereby improving the vertical space utilization rate of the battery cell 400 and improving the energy density of the battery cell 400. On the other hand, it is possible to reduce the possibility of the pressure relief device 10b colliding with other components during installation or use of the battery cell 400. On the other hand, when the battery cell 400 is applied to the battery 200 or the electricity consuming equipment 100, it is convenient to secure space above the battery cell 400 for installing other structural components such as a signal detection circuit.

[0124] Therefore, in the present application, the pressure relief device 10b can be quickly attached and detached, and is convenient for injecting liquid and discharging gas, thereby effectively improving the performance of the battery cell 400, eliminating the need to irreversibly destroy the battery cell 400 during the maintenance process, and not affecting the appearance of the battery cell 400.

[0125] Next, the proposal of the present application will be further explained in conjunction with the embodiments shown in FIGS. 1D to 23.

[0126] First, the first embodiment shown in FIGS. 1D to 7C will be described.

[0127] 1D , in this embodiment, the battery cell 400 is a rectangular battery cell and includes an electrode assembly 30 and a case 70 for accommodating the electrode assembly 30. The case 70 includes a housing 7 and an end cover assembly 10. The end cover assembly 10 is disposed on one side of the housing 7 and covers an end opening 71 of the housing 7 to form an enclosed space inside the case 70 for accommodating the electrode assembly 30 and the like.

[0128] As shown in FIGS. 2 and 3A, the end cover assembly 10 includes an end cover 10a, an electrode terminal 10c, an insulating member 10d, a seal ring 3, and a pressure relief device 10b. The end cover 10a is connected to the housing 7 to close an end opening 71 of the housing 7. A through-hole 11 is provided on the end cover 10a. The seal ring 3 is used to seal the through-hole 11. The insulating member 10d is provided between the end cover 10a and the electrode assembly 30 to provide insulation between the end cover 10a and the electrode assembly 30. Two electrode terminals 10c are provided on the end cover 10a, located on either side of the through-hole 11 along the longitudinal direction. The two electrode terminals 10c are electrically connected to the positive and negative tabs of the electrode assembly 30 via an adapter 20. The pressure relief device 10b is detachably provided on the end cover 10a and is inserted into the through-hole 11 between the two electrode terminals 10c, thereby achieving the functions of sealing the through-hole and safely relieving pressure.

[0129] 2 and 5 to 6B, the end cover 10a includes an end cover main body 1 and a mounting member 2. The end cover main body 1 is connected to the housing 7. The mounting member 2 is connected to one side of the end cover main body 1 remote from the electrode assembly 30. Specifically, the two electrode terminals 10c are provided on the end cover main body 1, a mounting groove 15 is provided between the two electrode terminals 10c, and the mounting member 2 is provided in the mounting groove 15. The mounting groove 15 is recessed toward the electrode assembly 30 from the surface of the end cover main body 1 opposite the electrode assembly 30, and the mounting member 2 is fixed to the mounting groove 15 by a method such as interference fit, bonding, connection with a fastener, or welding.

[0130] By providing mounting grooves 15 to accommodate the mounting members 2, the height of the mounting members 2 relative to the end cover body 1 can be reduced. As shown in FIG. 5 , the height of the battery cells 400 can be reduced by positioning the surface of the mounting members 2 away from the electrode assemblies 30 not to exceed the surface of the end cover body 1 away from the electrode assemblies 30, but to be lower or equal to the surface of the end cover body 1 away from the electrode assemblies 30.

[0131] As shown in Figures 3C and 4C, the mounting groove 15 is a tapered groove that is wider at the top and narrower at the bottom, and the side walls of the mounting groove 15 can act as a guide for the mounting component 2 during the process of mounting the mounting component 2. Meanwhile, when the mounting component 2 is fixed to the mounting groove 15 via laser welding, the mounting groove 15 also ensures that there are no gaps in the laser incidence path, thereby preventing welding explosions caused by gaps and improving the strength of the welded structure.

[0132] The through-hole 11 penetrates the mounting member 2 and the end cover body 1 and includes a first hole segment 111 located on the end cover body 1 and a second hole segment 26 located on the mounting member 2. The first hole segment 111 extends from the bottom of the mounting groove 15 to the surface of the end cover body 1 facing the electrode assembly 30. The second hole segment 26 is located on one side of the first hole segment 111 away from the electrode assembly 30 and communicates with the first hole segment 111. The diameter of the second hole segment 26 is larger than that of the first hole segment 111. Therefore, when the through-hole 11 is opened, liquid can be injected into the battery cell 400 or gas can be discharged from the battery cell 400 through the through-hole 11. Because the through-hole 11 has both the liquid injection and gas discharge functions, there is no need to provide separate liquid injection holes and exhaust passages. This reduces the number of holes on the end cover 10a, reduces the space occupied by the holes, increases space utilization, and improves the energy density of the battery cell 400.

[0133] The seal ring 3 is located at one end of the first hole segment 111, closer to the second hole segment 26, and seals the first hole segment 111, thereby achieving a seal for the through-hole 11. The seal ring 3 is covered by the pressure relief device 10b and compressed by the pressure relief device 10b, forming a sealing surface between the pressure relief device 10b and the end cover body 1. In this case, the coefficient of friction between the seal ring 3 and the pressure relief device 10b may be smaller than the coefficient of friction between the seal ring 3 and the end cover 10a, in order to reduce friction during rotation of the pressure relief device 10b, ease assembly, and reduce wear on the seal ring 3. To reduce the friction between the seal ring 3 and the pressure relief device 10b, methods such as applying lubricant between the seal ring 3 and the pressure relief device 10b or placing other spacers with low friction can be used.

[0134] In order to realize the detachable connection between the pressure relief device 10b and the end cover 10a, as shown in Figures 1D to 7C, in this embodiment, the pressure relief device 10b is rotatably inserted into the second hole segment 26, a first engagement portion 24 is provided on the end cover 10a, and a corresponding second engagement portion 42 is provided on the pressure relief device 10b. By realizing the rotational engagement between the pressure relief device 10b and the end cover 10a, the first engagement portion 24 and the second engagement portion 42 can be engaged or disengaged during the process of the pressure relief device 10b rotating between the first position and the second position relative to the end cover 10a, thereby realizing the attachment and detachment of the pressure relief device 10b to the end cover 10a, and further enabling the pressure relief device 10b to open and close the through-hole 11.

[0135] 1D to 7, in this embodiment, the first engagement portion 24 is a locking groove 24a, and the second engagement portion 42 is a locking post 42a. An engagement structure is formed between the locking groove 24a and the locking post 42a. When the pressure relief device 10b is rotated to the first position, all or part of the locking post 42a is positioned in the locking groove 24a, which limits the displacement of the pressure relief device 10b away from the electrode assembly 30, thereby preventing the pressure relief device 10b from coming off the end cover 10a and stably closing the through-hole 11. When the pressure relief device 10b is rotated to the second position, the locking post 42a and the locking groove 24a are displaced circumferentially around the through hole 11, and the locking post 42a is completely disengaged from the locking groove 24a. As a result, the displacement of the pressure relief device 10b away from the electrode assembly 30 is not restricted by the end cover 10a. This allows the pressure relief device 10b to be removed from the end cover 10a to open the through hole 11 for maintenance work such as liquid injection, gas discharge, and replacement of the pressure relief device 10b.

[0136] The first engaging portion 24 and the second engaging portion 42 are engaged or disengaged by rotating the pressure relief device 10b, resulting in a simple structure, relatively low requirements for fitting precision, and repeated use. In terms of processing, the arrangement of the locking posts 42a on the pressure relief device 10b and the arrangement of the locking grooves 24a in the end cover 10a are both easy to process, making this device particularly suitable for lithium-ion battery cells with relatively small overall sizes. In terms of installation and maintenance, the pressure relief device 10b is relatively easy to install and remove, improving the assembly efficiency of the battery cell 400 during manufacturing and reducing maintenance time during use.

[0137] Furthermore, by rotating the pressure relief device 10b to open and close the through-hole 11, maintenance work such as liquid injection, gas discharge, and pressure relief device 10b replacement can be performed without damaging the battery cell 400. Here, by removing the pressure relief device 10b and injecting liquid through the through-hole 11, secondary liquid injection can be performed, which effectively reduces capacity reduction of the battery cell 400 and extends the service life of the battery cell 400. By removing the pressure relief device 10b and discharging gas through the through-hole 11, the internal pressure of the battery cell 400 can be released, which shortens the time the inside of the battery cell 400 continuously acts on the pressure relief device 10b and prevents the pressure relief device 10b from creeping and bursting, which can cause problems with liquid and gas leakage, which is advantageous in extending the service life of the pressure relief device 10b. In addition, since the pressure relief device 10b can be removed and replaced, it is possible to not only meet the need to replace the pressure relief device 10b after it is damaged, but also to extend the service life of the battery cell 400 and meet the need to periodically replace the pressure relief device 10b even when it is not damaged, thereby reducing the requirements for the service life of the pressure relief device 10b and improving the reliability of use of the pressure relief device 10b.

[0138] 6A and 6B, in this embodiment, the locking groove 24a is formed by being surrounded by the mounting member 2 and the end cover main body 1. Specifically, the mounting member 2 includes a mounting ring 21 and a position limiting step 22. The hollow portion in the center of the mounting ring 21 forms a second hole segment 26. The position limiting step 22 is connected to the inner wall of the mounting ring 21 and protrudes radially inward from the inner wall of the mounting ring 21, with a gap between it and the surface of the mounting ring 21 that faces the electrode assembly 30. Therefore, as shown in FIG. 5, after the mounting member 2 is mounted in the mounting groove 15, the locking groove 24a used as the first engagement portion 24 is formed between the position limiting step 22 and the groove bottom of the mounting groove 15. In this case, the first engagement portion 24 is a locking groove 24a formed by being surrounded by the mounting member 2 and the end cover main body 1, and when Figures 3C, 4C, 5 and 6B are combined, the bottom wall of the position limiting step 22, the side wall of the mounting ring 21 and the bottom wall of the mounting groove 15 respectively form the first groove wall 243, the second groove wall 244 and the third groove wall 245 of the locking groove 24a, which limit the displacement of the locking post 42a in the vertical direction when it is inserted.

[0139] Furthermore, based on the above arrangement, the locking groove 24a is located on one side of the end cover 10a away from the electrode assembly 30, which is advantageous in preventing metal particles generated by friction during rotational engagement from falling directly into the housing 7 and causing a short circuit in the battery cell 400, thereby effectively improving the operational safety of the battery cell 400.

[0140] 5 to 6B, position limiting step 22 is disposed at one end of mounting ring 21 that is remote from first hole segment 111, and position limiting step 22 is disposed alongside the surface of mounting ring 21 that is remote from first hole segment 111. This allows for an increase in the height of locking groove 24a, which is advantageous in improving the engagement strength between first engagement portion 24 and second engagement portion 42.

[0141] As shown in FIGS. 7A to 7C, in this embodiment, the pressure relief device 10b includes a main body 4 and a pressure relief member 5 to facilitate the placement of the locking post 42a and realize the sealing function of the pressure relief device 10b against the through-hole 11. The main body 4 has a disk-shaped or annular structure. The locking post 42a is provided on the outer wall of the main body 4 and protrudes outward from the outer wall of the main body 4 to form a cantilever structure. When the main body 4 is inserted into the second hole segment 26, the locking post 42a rotates along the main body 4 to engage with or disengage from the locking groove 24a. A vent 414 is formed in the hollow central portion of the main body 4. The pressure relief member 5 is provided at the position of the vent 414 and closes the vent 414. When the internal pressure of the battery cell 400 reaches a threshold, the pressure relief member 5 is broken, releasing the blockage on the vent 414, allowing the through-hole 11 to communicate with the external environment through the vent 414, thereby carrying out the pressure relief process and fulfilling the role of safety protection.

[0142] Specifically, in this embodiment, the pressure relief member 5 and the main body 4 are integrally provided. The pressure relief member 5 is connected to one end of the main body 4 remote from the electrode assembly 30 and closes the external port of the vent 414, thereby achieving closure for the vent 414. Here, the pressure relief member 5 can be made of a metal layer 51 such as an aluminum sheet 522.

[0143] 4C and 7B or 7C, in this embodiment, a sinking groove 412 is formed on the stress relief member 5, and the sealing ring 3 is located inside the sinking groove 412. Specifically, the sinking groove 412 may be manufactured by stamping, and is recessed in the surface of the electrode assembly 30 of the stress relief member 5 in a direction away from the electrode assembly 30. This reduces the space occupied by the sealing ring 3, which is advantageous for reducing the overall height of the battery cell 400 and improving the energy density of the battery cell 400.

[0144] 7B and 7C, in this embodiment, a circumferential notch 53 is disposed on the pressure relief member 5. When the internal pressure of the battery cell 400 reaches a threshold, the notch 53 breaks first, realizing directional gas discharge pressure relief for the battery cell 400 and preventing the battery cell 400 from exploding due to excessive internal pressure. Here, the notch 53 is located radially inward of the inner ring of the sealing ring 3, and can prevent the notch 53 from accidentally breaking due to the elastic force of the sealing ring 3.

[0145] 7A or 7C, in this embodiment, at least two locking posts 42a are provided on the outer wall of the main body 4, and these at least two locking posts 42a are spaced apart along the circumferential direction of the main body 4 and all extend along the circumferential direction of the through-hole 11. In this case, as shown in FIGS. 5 to 6B, the number of position limiting steps 22 surrounded by the locking grooves 24a on the end cover 10a is also at least two, and the position limiting steps 22 extend along the circumferential direction of the through-hole 11 and correspond one-to-one to the locking posts 42a. Therefore, at least two locking grooves 24a are arranged on the end cover 10a, and the locking grooves 24a extend along the circumferential direction of the through-hole 11 and correspond one-to-one to the locking posts 42a. Based on this, multiple positions are defined and supported when the pressure relief device 10b is in the first position. This is not only advantageous in improving the mounting stability and robustness of the pressure relief device 10b, but also in reducing the engagement force that a single locking post 42a must bear, thereby reducing the strength requirements of the locking post 42a.

[0146] The rotation angle of the pressure relief device 10b between the first position and the second position can be adjusted by setting the number and spacing angle of the position limiting steps 22. For example, if two position limiting steps 22 are arranged on the mounting member 2 so that they face each other, the pressure relief device 10b can be rotated from the first position to the second position or from the second position to the first position by simply rotating it 90°, which is advantageous in improving the efficiency of attachment and detachment. Of course, the angle between the first position and the second position of the pressure relief device 10b is not limited to 90° and may vary within a range of, for example, 60° to 120°, and can be specifically set according to actual needs.

[0147] As can be seen from Figures 5 to 6B, a guide groove 25 is formed in the space between the two spaced apart positioning steps 22. The guide groove 25 communicates with the locking groove 24a and guides the locking post 42a to move in and out of the locking groove 24a, thereby improving the smoothness of the rotational engagement process. Here, when the pressure relief device 10b is in the second position, the circumferential length of the guide groove 25 can be greater than the circumferential length of the locking groove 42a so as to accommodate the locking post 42a. On the other hand, the length of the guide groove 25 does not exceed the circumferential length of the locking groove 24a, thereby maximizing the engagement length between the locking post 42a and the locking groove 24a and improving the stability of positioning.

[0148] The guide groove 25 not only guides the locking post 42a to smoothly enter and exit the locking groove 24a, but also provides an inclined surface 42b on the locking post 42a, as shown in FIG. 7A. The inclined surface 42b can be used to guide the locking post 42a when entering and exiting the locking groove 24a. Specifically, the inclined surface 42b is disposed along the circumferential sidewall of the locking post 42a, and the thickness of the sidewall of the locking post 42a gradually decreases from the center to the outside along the circumferential direction. Based on this, the inclined surface 42b allows the locking post 42a to smoothly enter the locking groove 24a without the need for pre-adjustment of the height of the locking post 42a, thereby improving assembly efficiency. This prevents collisions between the locking post 42a and the locking groove 24a at the entrance, which is advantageous for improving the service life of the end cover assembly 10 and reducing scrap metal generation.

[0149] Here, the inclined surface 42b may be a flat surface or an arcuate surface. The inclined surface 42b may be disposed on one or both circumferential sides of the locking post 42a. Disposing all inclined surfaces 42b on both circumferential sides of the locking post 42a is advantageous in guiding the locking post 42a to smoothly enter and exit the locking groove 24a.

[0150] The inclined surface 42b is disposed on the locking post 42a, which facilitates processing. Alternatively, the inclined surface 42b may be disposed on a groove wall of the locking groove 24a, for example, on the first groove wall 243 or the second groove wall 244.

[0151] To facilitate the rotation of the locking post 42a into and out of the locking groove 24a, the height of the locking groove 24a may be greater than that of the locking post 42a. Therefore, after the locking post 42a enters the locking groove 24a, the locking post 42a comes into contact with the first groove wall 243 due to the elastic force of the seal ring 3, while there is a gap between the bottom surface of the locking post 42a and the second groove wall 244.

[0152] 3A-3C and 4A-4C show the pressure relief device 10b in the first and second positions, respectively. When the pressure relief device 10b is rotated to the first position, as shown in FIGS. 3A-3C, the locking posts 42a are inserted into the locking grooves 24a, which prevent the pressure relief device 10b from being removed from the end cover 10a. When the pressure relief device 10b is rotated to the second position, as shown in FIGS. 4A-4C, the locking posts 42a are disengaged from the locking grooves 24a and inserted into the guide grooves 25. The pressure relief device 10b is no longer restricted by the locking grooves 24a and can be removed from the end cover 10a, opening the through-hole 11.

[0153] 3C , when the pressure relief device 10b is in the first position, the locking post 42a abuts against the first groove wall 243 of the locking groove 24a, which is away from the electrode assembly 30, so that the first groove wall 243 limits the displacement of the pressure relief device 10b away from the electrode assembly 30 and prevents the pressure relief device 10b from being separated from the end cover 10a. More specifically, the first groove wall 243 includes a protrusion 243a, which protrudes toward one side of the electrode assembly 30 relative to the rest of the first groove wall 243 and abuts against the locking post 42a, causing the first groove wall 243 to abut against the locking post 42a via the protrusion 243a.

[0154] Furthermore, in order to reduce resistance when the pressure relief device 10b rotates, a gap may be provided between the second groove wall 244 facing the first groove wall 243 and the locking post 42a. Similarly, in order to reduce resistance when the pressure relief device 10b rotates, a gap may be provided between the third groove wall 245 connected between the first groove wall 243 and the second groove wall 244 and the locking post 42a.

[0155] When the pressure relief device 10b needs to be installed, a downward force is applied to the pressure relief device 10b, and the deformation of the seal ring 3 creates a gap between the locking post 42a and the first groove wall 243. In this case, the pressure relief device 10b is rotated so that the locking post 42a smoothly enters the locking groove 24a and reaches the first position, after which the pressure relief device 10b is released. The pressure relief device 10b moves under the action of the elastic force of the seal ring 3 until the top surface of the locking post 42a abuts against the first groove wall 243. In this case, a gap (not shown) may occur between the bottom surface of the locking post 42a and the second groove wall 244.

[0156] When it is necessary to remove the pressure relief device 10b, a downward force is applied to the pressure relief device 10b, and the deformation of the sealing ring 3 creates a gap between the locking post 42a and the first groove wall 243. In this case, the pressure relief device 10b is rotated so that the locking post 42a smoothly shifts circumferentially from the locking groove 24a and the entire device is positioned within the guide groove 25. In this case, when the pressure relief device 10b reaches the second position, it can be removed and operations such as liquid injection, gas discharge, or replacement of the pressure relief device 10b can be performed.

[0157] Here, the first groove wall 243, the second groove wall 244, and the third groove wall 245 may be flat or arcuate. If the contact surfaces between the first groove wall 243 and the locking post 42a are all flat, the contact area between the first groove wall 243 and the locking post 42a can be increased, improving the stability of the engagement and increasing the frictional force between the first groove wall 243 and the locking post 42a, thereby increasing the difficulty of rotating the pressure relief device 10b circumferentially relative to the end cover 10a in the engaged state.

[0158] 7A to 7C, in this embodiment, in order to easily realize the rotation of the pressure relief device 10b, the pressure relief device 10b further includes an operating unit 411, which is used to accept an external operation and drive the rotation of the pressure relief device 10b. By arranging the operating unit 411, it is convenient to rotate the pressure relief device 10b by fitting a tool or the like to the operating unit 411, which is convenient to apply an external force when attaching or detaching the pressure relief device 10b, and it is easy to control the rotation angle of the pressure relief device 10b.

[0159] Specifically, as shown in FIG. 7A , in this embodiment, at least two bosses 411a are arranged on the surface of the pressure relief member 5 away from the electrode assembly 30. These at least two operating portions 411 are spaced apart along the circumferential direction of the through-hole 11, and the operating portions 411 include grooves 411b between two adjacent bosses 411a. In this case, a tool can be inserted into the grooves 411b to rotate the pressure relief device 10b. The assembly process for the battery cell 400 of this embodiment is as follows: First, the mounting member 2 is seated in the mounting groove 15 and welded. Next, electrolyte is injected through the through-hole 11, and the sealing ring 3 is attached after the liquid injection is completed. Next, the pressure relief device 10b is attached to the second position on the end cover 10a so as to cover at least a portion of the sealing ring 3. The locking posts 42a of the pressure relief device 10b and the locking grooves 24a of the end cover 10a are shifted circumferentially and disengaged from each other. Then, a special tool is used to hook groove 411b and apply a downward force, forming a gap between locking post 42a and first groove wall 243 of locking groove 24a, and pressure relief device 10b is rotated from the second position to the first position, hooking locking post 42a into locking groove 24a and restricting separation of pressure relief device 10b and end cover 10a. After rotating to the predetermined position, pressure relief device 10b is released, and pressure relief device 10b rises under the action of the elastic force of seal ring 3, so that pressure relief device 10b and first groove wall 243 abut against each other.

[0160] If maintenance operations such as injecting a secondary liquid, discharging gas, or replacing the pressure relief device 10b are required for the battery cell 400, a tool is used to engage the groove portion 411b and rotate the pressure relief device 10b in the opposite direction, returning the pressure relief device 10b from the first position to the second position, removing the pressure relief device 10b, removing the sealing ring 3, and after completing operations such as injecting liquid and discharging gas, repeating the above-mentioned installation process will complete the maintenance for the battery cell 400.

[0161] Next, a second embodiment will be described with reference to Figures 8 to 10A. For the sake of convenience, only the differences between the second embodiment and the first embodiment will be emphasized.

[0162] As shown in FIGS. 8 to 10A, the main difference between the second embodiment and the first embodiment is the structure of the pressure relief device 10b.

[0163] Specifically, as can be seen from FIGS. 8 to 10A, in the second embodiment, the main body 4 and the pressure relief member 5 of the pressure relief device 10b are not integrally arranged but are arranged separately. Here, the pressure relief member 5 still uses a metal layer 51 structure, such as an aluminum sheet 522, but is not connected to the end of the main body 4 far from the electrode assembly 30 but is instead located between the main body 4 and the sealing ring 3. In this case, the pressure relief member 5 covers the sealing ring 3 and closes the opening at the end of the vent 414 of the main body 4 closest to the electrode assembly 30 (i.e., the lower end opening of the vent 414), thereby sealing the vent 414 and also the through-hole 11. After the pressure relief member 5 is destroyed, the through-hole 11 is connected to the external environment via the vent 414, allowing for liquid injection and gas replenishment processes.

[0164] Because the pressure relief member 5 is not connected to the main body 4, when the main body 4 rotates, the pressure relief member 5 does not rotate together with the main body 4, but rather there is relative rotation between the main body 4 and the pressure relief member 5. In this case, in order to reduce wear on the pressure relief member 5 during the rotation of the main body 4, as shown in FIG. 8, the pressure relief device 10b of the second embodiment further includes a split ring 6, which is disposed between the main body 4 and the pressure relief member 5 to separate the main body 4 and the pressure relief member 5, thereby reducing wear on the pressure relief member 5 during the rotation of the main body 4 and providing protection for the pressure relief member 5.

[0165] 10B and 10C show a first modified example and a second modified example, respectively, of the pressure relief member 5 shown in FIG. 10A.

[0166] 10B and 10C, in the first and second modified examples, the pressure relief member 5 does not have a single-layer structure but a multi-layer structure. Specifically, the pressure relief member 5 is an aluminum-plastic film 52, and includes a first protective layer 521 made of nylon or PET material, a second protective layer 523 made of polypropylene material, and a metal layer 51 such as an aluminum sheet 522 positioned between the first protective layer 521 and the second protective layer 523.

[0167] The aluminum plastic film 52 has the same electrolyte penetration prevention and waterproofing capabilities as metal materials, and has better deformation resistance than the other metal layer 51 in which the notches 53 are located, so it is possible to prevent damage and liquid leakage caused by accidental deformation.

[0168] 10B and 10C, the differences between the two modified examples are as follows: In the first modified example shown in Fig. 10B, no notch 53 is arranged on the metal layer 51, whereas in the second modified example shown in Fig. 10C, a notch 53 is arranged on the metal layer 51, and the notch 53 is a cross-shaped groove 532 instead of an annular groove 531.

[0169] Compared with the first variant, in the second variant, a notch 53 is further arranged on the metal layer 51, which can reduce the pressure resistance value of the aluminum plastic film 52 and meet the safety protection needs of the battery cell 400 with a lower explosion pressure.

[0170] When the pressure relief member 5 is an aluminum plastic film 52, the split ring 6 provided between the pressure relief member 5 and the main body 4 prevents the aluminum plastic film 52 from being worn during the rotational engagement of the main body 4, thereby preventing the aluminum plastic film 52 from being worn and causing sealing failure.

[0171] Next, a third embodiment will be described with reference to FIGS.

[0172] 12 to 17, the main differences between the third embodiment and the above-described embodiments are as follows: the pressure relief device 10b does not include only one pressure relief member 5, but includes at least two pressure relief members 5, which are connected to each other, and when the internal pressure of the battery cell 400 reaches a threshold value, the pressure relief device 10b is broken at the connection position of the pressure relief members 5.

[0173] 15 to 17, in the third embodiment, the pressure relief device 10b includes two pressure relief members 5, which partially overlap each other and are connected by heat sealing at the overlapping portion 524. More specifically, the pressure relief member 5 is an aluminum plastic film 52.

[0174] Based on the above arrangement, an aluminum-plastic film seal is formed between two aluminum-plastic films 52 by heat sealing. During the heat-sealing process, the seal strength can be controlled to be much lower than the pressure resistance of the aluminum-plastic film 52 itself, thereby achieving a lower threshold for pressure relief and explosion prevention. Furthermore, compared with the method of forming a notch 53 on the metal layer 51 of the aluminum-plastic film 52, the heat-sealing process is easier to operate, avoiding the difficulty of controlling the notch 53 on the metal layer 51 and improving production efficiency.

[0175] 12 to 15, in the third embodiment, the overlapping portion 524 protrudes toward one side away from the seal ring 3 relative to the other portions of the pressure relief member 5, and a receiving groove 61 is arranged on the split ring 6, and the overlapping portion 524 is received in the receiving groove 61. Based on this, it is possible to prevent the overlapping portion 524 from protruding and causing uneven stress between the main body 4 and the pressure relief member 5.

[0176] On the other hand, as shown in FIG. 17 , in the third embodiment, the overlapping portion 524 is bent to one side closer to the electrode assembly 30, and the height of the overlapping portion 524 is reduced compared to when the overlapping portion 524 is not bent, which reduces the height of the end cover assembly 10 and improves the space utilization rate in the height direction of the battery cell 400, which is advantageous for improving the energy density of the battery cell 400.

[0177] As a variation of the third embodiment pressure relief device 10b, as shown in FIG. 18, the two pressure relief members 5 still partially overlap, but the overlapping portion 524 is not folded, and the pressure relief member 5 has a single layer structure rather than a multi-layer structure.

[0178] As another variation of the pressure relief device 10b of the third embodiment, as shown in FIG. 19, the two pressure relief members 5 are still multi-layered, but there is no overlap between the two pressure relief members 5, and they are docked together.

[0179] Next, a fourth embodiment shown in FIGS. 20 to 23 will be introduced.

[0180] 20 to 23, the differences between the fourth embodiment and the previously described embodiments are mainly as follows: the main body 4 is not inserted into the mounting member 2 but is provided as a sleeve on the outside of the mounting member 2; the first engagement portion 24 is not formed surrounded by the mounting member 2 and the end cover main body 1 but is disposed on the mounting member 2 and is located on the outer wall of the mounting member 2; and correspondingly, the second engagement portion 42 is disposed on the inner wall of the main body 4.

[0181] By providing the pressure relief device 10b as a sleeve on the outside of the mounting member 2, an operator can easily apply an external force directly to the pressure relief device 10b to rotate it, which is convenient and easy to operate and does not require the design of special tools, thereby improving assembly and maintenance efficiency. Also, because the pressure relief device 10b is provided as a sleeve on the outside of the mounting member 2, the mounting member 2 generally needs to protrude from the surface of the end cover body 1. Therefore, locating the first engagement portion 24 on the outer wall of the mounting member 2 not only improves the strength of the end cover body 1, but also helps to reduce the thickness of the end cover body 1.

[0182] As shown in FIGS. 21 and 22 , the mounting member 2 includes a mounting ring 21 and a base 23. The base 23 is fixed in the mounting groove 15. For example, the base 23 may be fixed in the mounting groove 15 by interference fit, adhesive bonding, welding, or connection using a fastener. The mounting ring 21 is connected to one end of the base 23 remote from the electrode assembly 30. Therefore, the mounting ring 21 protrudes from the surface of the end cover body 1 remote from the electrode assembly 30, facilitating sleeve installation of the pressure relief device 10b. Furthermore, by disposing the base 23 in the mounting groove 15, the overall height of the end cover assembly 10 can be reduced to some extent. At the same time, the installed base 23 also facilitates the mounting stability of the mounting ring 21.

[0183] As shown in FIGS. 22 and 23 , in the fourth embodiment, the first engagement portion 24 is a locking groove 24a disposed on the outer wall of the mounting ring 21, and the corresponding second engagement portion 42 is a locking post 42a disposed on the inner wall of the main body 4. When the pressure relief device 10b is rotated to the first position, the locking post 42a is embedded in the locking groove 24a, thereby achieving attachment of the pressure relief device 10b to the end cover 10a. Specifically, as shown in FIG. 22 , the locking groove 24a is located on one side of the mounting ring 21 closer to the base 23, and the upper surface of the base 23 serves as a second groove wall 244. Here, the locking groove 24a includes a first locking groove 241 that extends circumferentially around the mounting ring 21. The locking groove 24a further includes a second locking groove 242. The second locking groove 242 communicates with the first locking groove 241 and is located above the first locking groove 241, i.e., the second locking groove 242 is located on one side of the first locking groove 241 that is farther from the base 23. In this case, when the pressure relief device 10b is rotated to the first position, the locking post 42a is embedded in the second locking groove 242 and has a gap with the base 23, so that the pressure relief device 10b experiences less resistance during the rotation process.

[0184] At least two locking grooves 24a can be spaced apart along the circumferential direction, and correspondingly, at least two locking posts 42a can be arranged along the circumferential direction. In this case, as shown in FIG. 22, a guide groove 25 can be arranged between adjacent locking grooves 24a to guide the locking posts 42a so that they can smoothly move in and out of the locking grooves 24a. Specifically, the tip of the guide groove 25 penetrates the top of the mounting ring 21. The bottom end of the guide groove 25 communicates with the locking groove 24a. More specifically, the bottom end of guide groove 25 communicates with one side of first locking groove 241 away from second locking groove 242, and guide groove 25 and locking groove 24a are connected to form an L-shaped groove, so that when main body 4 is sleeved and rotated on mounting ring 21, locking post 42a can smoothly advance into locking groove 24a under the guiding action of guide groove 25 and engage with second locking groove 242.

[0185] 21 and 23, in the fourth embodiment, the arrangement of the pressure relief member 5 is similar to that of the first embodiment, and it is still integrally arranged at one end of the body 4 remote from the electrode assembly 30. The arrangement of the sealing ring 3 is different, however, the sealing ring 3 is not arranged at the end of the first hole segment 111 close to the second hole segment 26, but is arranged within the pressure relief device 10b, specifically, between the locking post 42a and the pressure relief member 5, and the sealing ring 3 is compressed by the pressure relief device 10b to improve the sealing effect.

[0186] The assembly process of the battery cell 400 of the fourth embodiment is as follows.

[0187] First, the mounting member 2 is inserted into the mounting groove 15 and welded. Next, electrolyte is injected through the through-hole 11. Next, the sealing ring 3 is bonded to the underside of the pressure relief member 5. Finally, the pressure relief device 10b is sleeved onto the outside of the mounting member 2. During the sleeve installation, the locking post 42a enters the locking groove 24a through the guide groove 25. After the locking post 42a reaches the locking groove 24a, a downward force is applied to the pressure relief device 10b, rotating it until it reaches the first position. The locking post 42a moves within the locking groove 24a. After the locking post 42a reaches the second locking groove 242, the pressure relief device 10b is released. The pressure relief device 10b rises under the elastic force of the sealing ring 3 and abuts against the upper wall of the second locking groove 242, preventing the pressure relief device 10b from separating from the end cover 10a. This completes the assembly process.

[0188] If a secondary liquid injection is required for the battery cell 400, rotate the pressure relief device 10b in the opposite direction, rotate the pressure relief device 10b from the first position to the second position, remove the pressure relief device 10b and the sealing ring 3, inject the liquid, and after the liquid injection is completed, repeat the above-mentioned assembly process to complete the maintenance of the battery cell 400.

[0189] As can be seen from the above introduction, the embodiments of the present application all have an integrated liquid injection and explosion-proof structure, which can quickly install and remove the pressure relief device 10b without damaging the battery cell 400, and can easily perform maintenance operations such as liquid injection, gas discharge, and pressure relief device replacement, thereby effectively improving the energy density of the battery cell 400, extending the service life of the battery cell 400, and improving the operating reliability of the battery cell 400, thereby effectively improving the performance of the battery cell 400.

[0190] As an improvement of the end cover assembly 10 based on the above-described embodiments, referring to Fig. 24, the present application further provides a housing assembly 700 for use with a battery cell 400, the housing assembly 700 including a housing 7, a through hole 11, and a force absorbing device 10b. Here, the housing 7 is connected to the end cover 10a to form a case 70 of the battery cell 400, and is provided with a through hole 11 and a first engaging portion 24, the first engaging portion 24 being provided along the circumferential direction of the through hole 11 and located on one side of the housing 7 away from the interior of the battery cell, The sealing ring 3 is for sealing the through hole 11, and the pressure relief device 10b is configured to cover at least a portion of the sealing ring 3, close the through hole 11, and release the closure of the through hole 11 when the internal pressure of the housing 7 reaches a threshold value.

[0191] Here, the pressure relief device 10b is rotatable and includes a second engagement portion 42, and when the pressure relief device 10b rotates to the first position, the second engagement portion 42 engages with the first engagement portion 24, restricting separation between the pressure relief device 10b and the end cover 10a, and when the pressure relief device 10b rotates to the second position, the second engagement portion 42 disengages from the first engagement portion 24, realizing separation between the pressure relief device 10b and the housing 7.

[0192] Based on the above arrangement, the through hole 11, the seal ring 3, and the pressure relief device 10b are not disposed in the end cover 10a, but are disposed on the housing 7 connected to the end cover 10a. Here, the pressure relief device 10b can be any of the embodiments described in the section on the end cover assembly 10.

[0193] Unlike the end cover 10a, the housing 7 does not require the placement of other components such as the electrode terminal 10c or the end cover temperature sampling structure. Therefore, the housing 7 has a relatively large free area, which makes it easier to place the through-hole 11, the sealing ring 3, and the pressure relief device 10b. Furthermore, when the through-hole 11 is placed on the housing 7, which has a relatively large free area, it is easier to increase the size of the through-hole 11 and the pressure relief device 10b, which is advantageous to further improve the liquid injection efficiency, the structural strength of the pressure relief device 10b, and the closure reliability of the pressure relief device 10b against the through-hole 11. At the same time, a relatively large operating space can be provided for the attachment and detachment of the pressure relief device 10b, improving the attachment and detachment efficiency.

[0194] 24, the through-holes 11 are arranged in the wall surface adjacent to the end cover 10a of the housing 7, and the battery cells 400 can be stably mounted with the end cover 10a facing upward. For example, when the through-holes 11 are arranged in the wall surface adjacent to the largest side surface of the housing 7 and a battery module 300 is formed with multiple battery cells 400 arranged horizontally or vertically, the largest side surfaces of the adjacent battery cells 400 are kept in contact with each other, thereby making the structure of the battery module 300 more stable and reducing its volume.

[0195] The housing assembly 700 provided in the present application allows the pressure relief device 10b to be flexibly attached and detached repeatedly. When the electrolyte is insufficient or the performance of the electrolyte is deteriorated, the pressure relief device 10b can be conveniently removed to carry out secondary liquid injection and discharge the gas inside the battery cell 400. After the secondary liquid injection is completed, the through-hole 11 can be stably closed. This ensures the operational reliability of the battery cell 400 after the secondary liquid injection, and allows the appearance of the battery cell 400 to be maintained as it was before the liquid injection.

[0196] In the present application, when the housing assembly 700 is included, the case 70 does not include the end cover assembly 10 of each of the above-described embodiments, but includes the end cover 10a.

[0197] In addition, the present application further provides a liquid injection method for the battery cell 400. Referring to FIG. 25, the liquid injection method includes: Step S101: injecting an electrolyte into the battery cell 400 through the housing 7 of the case 70 of the battery cell 400 or the through-hole 11 on the end cover 10a; Step S102 of placing the pressure relief device 10b at a second position on the housing 7 or the end cover 10a so that the pressure relief device 10b covers at least a portion of the seal ring 3, and the second engagement portion 42 of the pressure relief device 10b is arranged along the circumferential direction of the through-hole 11 on the case 70 and is disengaged from the first engagement portion 24 located on one side of the case 70 away from the interior of the battery cell 400; and step S103 of rotating the pressure relief device 10b from the second position to the first position so that the second engagement portion 42 engages with the first engagement portion 24, limiting separation of the pressure relief device 10b from the housing 7 or the end cover 10a.

[0198] Compared to the conventional method of closing the liquid injection hole using a laser welding method, the present invention not only eliminates the welding sealing process of the liquid injection hole, but also eliminates several processes, such as cleaning the welding slag generated by the welding and drying the remaining liquid after cleaning. Therefore, the present invention improves the manufacturing efficiency of battery cells. The present invention achieves engagement and disengagement between the second engaging portion 42 and the first engaging portion 24 by rotating the pressure relief device 10b, which is simple and quick. This improves the assembly efficiency of the pressure relief device 10b during the assembly process of the battery cell 400, and therefore further improves the production efficiency of battery cells.

[0199] Furthermore, as shown in FIG. 26, before placing the pressure relief device 10b in the second position on the housing 7 or the end cover 10a in step S102, the liquid injection method further includes step S102A of attaching the seal ring 3 to the case 70.

[0200] In this embodiment, the seal ring 3 is attached to the case 70 in advance, and after the pressure relief device 10b is attached, it can directly cover the seal ring 3 or generate a pressing force against the seal ring 3, thereby achieving a better sealing effect for the through hole 11. For example, in each of the embodiments shown in FIGS. 1D to 19, the seal ring 3 may be attached to the end cover 10a in advance. In the embodiments shown in FIGS. 20 to 23, the seal ring 3 may be bonded to the underside of the pressure relief member 5 in advance.

[0201] Continuing with reference to FIG. 26, in some embodiments, a liquid injection method includes: Step S104: rotating the pressure relief device 10b from the first position to the second position so that the second engagement portion 42 is disengaged from the first engagement portion 24; The method further includes a step S105 of separating the pressure relief device 10b from the housing 7 or the end cover 10a.

[0202] Removing the pressure relief device 10b from the case 70 facilitates maintenance operations such as liquid injection, gas discharge, or replacement of the pressure relief device 10b. For example, after step S105, step S106 can be performed to replenish the electrolyte inside the battery cell 400 through the through-hole 11, thereby achieving a secondary liquid injection function.

[0203] After the maintenance is completed, the installation of the pressure relief device 10b can be completed through steps S101 to S103, and the through-hole 11 can also be closed, which is simple and convenient.

[0204] This liquid injection method allows the pressure relief device 10b to be flexibly and conveniently attached and detached repeatedly, and can stably close the through-hole 11 after the secondary liquid injection is completed, ensuring the operational reliability of the battery cell 400 after the secondary liquid injection and maintaining the same appearance of the battery cell as before the liquid injection. It also reduces maintenance time during the secondary liquid injection, and if the performance of the battery cell 400 deteriorates, it is possible to replenish the liquid in a timely manner to ensure the operational performance of the battery cell 400.

[0205] In addition, after step S105 of separating the pressure relief device 10b from the housing 7 or the end cover 10a, the sealing ring 3 is first removed to facilitate the discharge of the electrolyte in the case 70, thereby preventing the electrolyte from leaking into the sealing ring 3, keeping the sealing ring 3 clean, and extending its service life.

[0206] Finally, the present application further provides a liquid injection device 600 that can inject liquid into the battery cell 400 and realize the above-mentioned liquid injection method. As shown in FIG. 27, in some embodiments, the liquid injection device 600 includes: a liquid injection mechanism 601 configured to inject an electrolyte into the case 70 through a through-hole 11 provided on the case 70; and and a first detachment mechanism 602 that, when the pressure relief device 10b is located in the second position, rotates the pressure relief device 10b from the second position to the first position, changing the second engagement portion 42 of the pressure relief device 10b and the first engagement portion 24 on the case 70 from a disengaged state to an engaged state, thereby limiting separation of the pressure relief device 10b from the housing 7 or the end cover 10a of the case 70.

[0207] Compared to the conventional method of closing the liquid injection hole by laser welding, the present invention not only eliminates the welding sealing process of the liquid injection hole, but also eliminates several processes such as the subsequent cleaning of the welding slag generated by the welding and drying of the remaining liquid after cleaning. The liquid injection device 600 can manufacture the battery cell 400 simply and efficiently, thereby improving the manufacturing efficiency of the battery cell 400.

[0208] Continuing with reference to FIG. 27, in some embodiments, the first detachment mechanism 602 is also arranged to rotate the pressure relief device 10b from the first position to the second position so that the second engagement portion 42 disengages from the first engagement portion 24, thereby facilitating removal of the pressure relief device 10b from the case 70.

[0209] 27 , in some embodiments, the liquid injection device 600 further includes a second detachment mechanism 603, which is configured to attach the sealing ring 3 to the case 70 or detach the sealing ring 3 from the case 70, for example, to detach the sealing ring 3 from the case 70 after the pressure relief device 10b has been removed from the case 70. This facilitates the detachment and attachment of the sealing ring 3 during battery cell assembly and battery cell maintenance such as secondary liquid injection, thereby improving the detachment efficiency, reducing contamination of the sealing ring 3, and improving the service life of the sealing ring 3.

[0210] The liquid injection device 600 provided in the present application can flexibly and conveniently assist in the detachment and installation of the pressure relief device 10b during the battery cell maintenance process, such as battery cell manufacturing and assembly and secondary liquid injection. It is easy to operate and is advantageous for improving the assembly efficiency of the battery cell 400, shortening the maintenance time required for the battery cell 400, and ensuring the working performance of the battery cell 400 by timely replenishing liquid when the performance of the battery cell 400 deteriorates.

[0211] The features of each of the aforementioned protection subjects and embodiments of this application can be mutually referenced, and where the structure allows, those skilled in the art can flexibly combine the technical features of different embodiments to form more embodiments.

[0212] The battery cell end cover assembly, the battery cell, and the device using the battery cell provided in this application have been introduced in detail above. Although specific examples have been used in this specification to explain the principles and embodiments of this application, the explanation of the above examples is only used to help understand the method and key ideas of this application. It should be noted that those skilled in the art may make minor improvements and modifications to this application without departing from the principles of this application, and all such improvements and modifications are within the scope of protection of this application.

Claims

1. An end cover assembly (10) for use with a battery cell (400), comprising: The end cover assembly (10) comprises: an end cover (10a) provided with a through hole (11) for injecting an electrolyte and a first engagement portion (24); a seal ring (3) for sealing the through hole (11); a pressure relief device (10b) that covers at least a portion of the seal ring (3), closes the through hole (11), and is broken when the internal pressure of the battery cell (400) reaches a threshold value to release the blockage of the through hole (11) and release the internal pressure of the battery cell (400); the first engagement portion (24) is arranged along the circumferential direction of the through-hole (11) and is located on one side of the end cover (10a) away from the interior of the battery cell (400); the pressure relief device (10b) is rotatable and includes a second engagement portion (42), configured such that when the pressure relief device (10b) is rotated to a first position, the second engagement portion (42) engages with the first engagement portion (24) to restrict separation between the pressure relief device (10b) and the end cover (10a), and when the pressure relief device (10b) is rotated to a second position, the second engagement portion (42) disengages from the first engagement portion (24) to allow separation between the pressure relief device (10b) and the end cover (10a); The pressure relief device (10b) is provided with a sinking groove (412), and the sealing ring (3) is disposed in the sinking groove (412); The first engagement portion (24) is one of the locking groove (24a) and the locking post (42a), and the second engagement portion (42) is the other of the locking groove (24a) and the locking post (42a). An end cover assembly (10) comprising:

2. The pressure relief device (10b) includes a main body (4) and a pressure relief member (5), the main body (4) is connected to the second engagement portion (42), the pressure relief member (5) closes the through-hole (11), and the pressure relief member (5) is broken when the internal pressure of the battery cell (400) reaches the threshold value, thereby releasing the internal pressure. The end cover assembly (10) of claim 1.

3. The pressure relief member (5) and the main body (4) are provided integrally or separately. The end cover assembly (10) of claim 2.

4. The pressure relief member (5) and the main body (4) are provided separately, and the pressure relief member (5) is provided between the main body (4) and the seal ring (3). The end cover assembly (10) of claim 3.

5. The pressure relief device (10b) further includes a split ring (6) provided between the main body (4) and the pressure relief member (5), dividing the main body (4) and the pressure relief member (5) to protect the pressure relief member (5). The end cover assembly (10) of claim 4.

6. The split ring (6) is attached to the pressure relief member (5). The end cover assembly (10) of claim 5.

7. The pressure relief member (5) includes a metal layer (51) and a protective layer (52a), the protective layer (52a) is laminated with the metal layer (51), and the elongation rate of the protective layer (52a) is greater than the elongation rate of the metal layer (51). An end cover assembly (10) according to any one of claims 3 to 6.

8. The pressure relief device (10b) includes at least two pressure relief members (5) connected to each other, and when the internal pressure of the battery cell (400) reaches the threshold value, the connected portions of the at least two pressure relief members (5) are punched out to release the internal pressure. An end cover assembly (10) according to any one of claims 2 to 7.

9. The at least two pressure relief members (5) dock or overlap each other. The end cover assembly (10) of claim 8.

10. The at least two pressure relief members (5) partially overlap, and the overlapping portions (524) of the at least two pressure relief members (5) protrude to one side away from the sealing ring (3) relative to the remaining portions of the at least two pressure relief members (5). The end cover assembly (10) of claim 9.

11. The overlapping portions (524) of the at least two pressure relief members (5) are folded to reduce the height of the overlapping portions (524). The end cover assembly (10) of claim 10.

12. The split ring (6) of the pressure relief device (10b) is provided with a receiving groove (61), and the overlapping portions (524) of the at least two pressure relief members (5) are received in the receiving groove (61). An end cover assembly (10) according to claim 10 or 11.

13. The at least two pressure relief members (5) are connected by heat sealing. An end cover assembly (10) according to any one of claims 8 to 12.

14. The pressure relief member (5) is an aluminum plastic film (52). An end cover assembly (10) according to any one of claims 3 to 13.

15. The end cover assembly (10) further includes a guide groove (25), which communicates with the locking groove (24a), and the locking post (42a) passes through the guide groove (25) and moves in and out of the locking groove (24a) during rotation of the pressure relief device (10b). An end cover assembly (10) according to any one of the preceding claims.

16. A housing assembly (700) for use with a battery cell (400), comprising: a housing (7) that is connected to the end cover (10a) to form a case (70) for the battery cell (400), and that is provided with a through hole (11) and a first engagement portion (24); a seal ring (3) for sealing the through hole (11); a pressure relief device (10b) configured to cover at least a portion of the sealing ring (3), close the through hole (11), and release the closure of the through hole (11) when the internal pressure of the housing (7) reaches a threshold value; the first engagement portion (24) is provided along the circumferential direction of the through hole (11) and is located on one side of the housing (7) away from the inside of the battery cell; the pressure relief device (10b) is rotatable and includes a second engagement portion (42), configured such that when the pressure relief device (10b) is rotated to a first position, the second engagement portion (42) engages with the first engagement portion (24) to limit separation between the pressure relief device (10b) and the end cover (10a), and when the pressure relief device (10b) is rotated to a second position, the second engagement portion (42) disengages from the first engagement portion (24) to achieve separation between the pressure relief device (10b) and the housing (7); The pressure relief device (10b) is provided with a sinking groove (412), and the sealing ring (3) is disposed in the sinking groove (412); The first engagement portion (24) is one of the locking groove (24a) and the locking post (42a), and the second engagement portion (42) is the other of the locking groove (24a) and the locking post (42a). A housing assembly (700) comprising:

17. An electrode assembly (30) and a case (70) for housing the electrode assembly (30), The case (70) includes a housing (7) and an end cover assembly (10) according to any one of claims 1 to 15, wherein the housing (7) has an end opening (71), and the end cover assembly (10) covers the end opening (71) of the housing (7), or The case (70) includes an end cover (10a) and a housing assembly (700) according to claim 16, wherein the housing (7) has an end opening (71), and the end cover (10a) is configured to cover the end opening (71) of the housing (7). A battery cell (400).

18. A battery (200) configured to include at least two battery cells (400) according to claim 17.

19. 20. An electrical consumer (100) comprising a battery cell (400) according to claim 17, wherein the battery cell (400) is used to provide electrical energy.

Images