End caps, end cap assemblies, battery cells, batteries and power consuming devices

Abstract

This application relates to an end cap, an end cap assembly, a battery cell, a battery, and an energy-consuming device. The end cap includes two through-holes extending through the end cap for mounting electrode terminals, a recess formed by recessing the surface of the end cap along the thickness direction, the bottom wall of the recess forming a pressure relief mechanism, and a weakened portion disposed on the pressure relief mechanism, which is configured to tear along the weakened portion when the internal pressure of the battery cell reaches a threshold, where the depth of the weakened portion gradually decreases along one or both sides of the perpendicular bisector of the connection line of the two through-holes in a direction away from the perpendicular bisector. The end cap according to this application is free of connection defects, has relatively high structural strength, and the pressure relief mechanism on the end cap allows pressure to be relieved in a directionally controllable manner, effectively improving the safety of the battery.

Description

[Technical Field]

[0001] The present application relates to the field of battery technology, and more particularly to end caps, end cap assemblies, battery cells, batteries, and power consuming devices.

[0002] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims priority to Chinese patent application No. 202122325362.6, entitled "End Cap, End Cap Assembly, Battery Cell, Battery, and Power Consumption Device," filed on September 24, 2021, the entire contents of which are incorporated herein by reference. [Background technology]

[0003] In the macro environment where energy conservation and reduction of pollutant emissions are required, electric vehicles, with their advantages of energy conservation and environmental protection, have become a new trend in the development of the automobile industry and are an important component of the sustainable development of the automobile industry.When using electric vehicles and other power-consuming devices, the batteries they carry are prone to safety issues if the internal pressure rises abnormally during the charging and discharging process.Battery safety is related to the safety of the device and the safety of the user, so how to improve battery safety is an important research and development direction. Summary of the Invention [Problem to be solved by the invention]

[0004] The present application is intended to provide an end cap, an end cap assembly, a battery cell, a battery, and a power consuming device that improves the safety of the battery. [Means for solving the problem]

[0005] An embodiment of the present application is realized as follows.

[0006] According to a first aspect, an embodiment of the present application provides an end cap for use with a battery cell, the end cap comprising: two through holes penetrating the end cap for attaching electrode terminals; a groove formed by recessing a surface of the end cap along a thickness direction, the bottom wall of the groove forming a pressure relief mechanism; a weak part disposed on the pressure relief mechanism for relieving internal pressure of the battery cell; Here, the depth of the weakened portion gradually decreases along one or both sides of the perpendicular bisector of the connecting line of the two through holes in a direction away from the perpendicular bisector.

[0007] While conventional pressure relief mechanisms are generally molded separately and then connected to the end caps, which makes connection defects likely to occur at the connection points, the end caps of the present application are molded directly onto the end caps, eliminating the need for connection and eliminating the problem of connection defects. The thickness of the pressure relief mechanism at the weakened portion is reduced, and the greater the depth of the weakened portion, the smaller the thickness of the pressure relief mechanism at the weakened portion. The pressure relief mechanism is used to release the internal pressure of the battery cell, and can release pressure spontaneously or passively. Optionally, when the internal pressure of the battery cell reaches a threshold, the pressure relief mechanism will tear along the weakened portion to release the internal pressure of the battery cell.

[0008] The weak parts on the conventional pressure relief mechanism are likely to affect the structural strength of the end cap, while the weak parts of the present application have the deepest depth only in a local area and are smaller in other areas. As the depth of the weak parts decreases, the thickness of the pressure relief mechanism gradually increases, improving the structural strength of the pressure relief mechanism and the structural strength of the end cap.

[0009] When the internal pressure of the battery cell increases, the end cap expands and deforms, and the perpendicular bisector of the connecting line between the two through-holes is the centerline of the stress deformation of the end cap, where stress on the end cap is relatively concentrated. Therefore, by locating the maximum depth of the weakened part of the pressure relief mechanism on the perpendicular bisector of the two through-holes, when the internal pressure of the battery cell reaches a threshold, the maximum stress experienced by the end cap acts on the maximum depth of the weakened part, ensuring that the weakened part of the pressure relief mechanism tears at the maximum depth. After the weakened part tears, the internal pressure of the battery cell acts on the pressure relief mechanism, making it easier for the pressure relief mechanism to continue tearing along the weakened part, increasing the valve opening area, achieving effective pressure relief and ensuring battery safety. The pressure relief mechanism limits the opening direction of the pressure relief mechanism to the direction of the tear of the weakened part, thereby taking proactive measures to further improve battery safety.

[0010] Therefore, the end cap according to the present application has no connection defects, the structural strength of the end cap is relatively high, and the pressure relief mechanism on the end cap can relieve pressure in a directionally controllable manner, so that the end cap can effectively improve the safety of the battery.

[0011] In some embodiments of the present application, the perpendicular bisector of the connecting line between the two through holes passes through the center of the weakened portion.

[0012] In the above technical solution, the deepest position of the weak part is in the center, and when the internal pressure of the battery cell reaches a threshold, the pressure relief mechanism tears from the center to both sides along the weak part, allowing the pressure relief mechanism to open quickly and relieve pressure quickly, thereby improving safety.

[0013] In some embodiments of the present application, the weakened portion is symmetrical about the perpendicular bisector.

[0014] In the above technical solution, the weakened part ensures that the force received on both sides of the perpendicular bisector is consistent, and the pressure relief mechanism tears from the center to both sides along the weakened part, thereby further controlling the opening direction of the pressure relief mechanism and improving safety.

[0015] In some embodiments of the present application, the groove is symmetrical with respect to the perpendicular bisector.

[0016] In the above technical solution, the groove is symmetrical about the perpendicular bisector, the weak part is symmetrical about the perpendicular bisector, and the pressure relief mechanism is symmetrical about the perpendicular bisector, so that the structural strength and stress-bearing capacity of the pressure relief mechanism on both sides of the perpendicular bisector are consistent, ensuring that both sides of the pressure relief mechanism open synchronously when the internal pressure of the battery cell reaches a threshold, making the opening direction of the pressure relief mechanism more accurate and ensuring higher safety.

[0017] In some embodiments of the present application, the end cap is circular, the perpendicular bisector passes through the center of the end cap, and the weakened portion extends circumferentially around the end cap.

[0018] The above technical solution ensures that the structural strength and bearing capacity of the two parts on both sides of the perpendicular bisector of the entire end cap are consistent, and that the stress of the end cap is concentrated on the perpendicular bisector. This ensures that the end cap first tears from the deepest point of the weak part on the perpendicular bisector, ensuring the opening direction of the pressure relief mechanism and ensuring the safety of the battery.

[0019] Furthermore, by extending the weakened portion along the circumferential direction of the end cap, the weakened portion is relatively far from the center of the end cap and close to the edge of the end cap. When the circular end cap is deformed under internal pressure, the deformation at the center is relatively large and the deformation at the edge is relatively small. Therefore, when the weakened portion is located close to the edge of the end cap under the same valve-opening pressure, the depth of the weakened portion must be relatively large to ensure that the pressure relief mechanism can tear along the weakened portion under internal pressure to open the valve. Because the entire end cap is thin, the pressure relief mechanism and the weakened portion can be more precise, and when the depth of the weakened portion is relatively large, the processing difficulty is relatively small and easy.

[0020] In some embodiments of the present application, the groove includes an arcuate wall and a flat wall, the arcuate wall and the flat wall are interlocked, and the arcuate wall extends along the circumferential direction of the end cap.

[0021] In the above technical solution, the groove is arranged in an arcuate shape, and when processing the weakened portion, the arcuate wall can be used as a reference, and the weakened portion can be processed along the arcuate wall, which is easy to process. Similarly, when compared with a waist-shaped or other shape having an arcuate portion, if the length of the weakened portion is constant, i.e., the length of the arcuate wall is constant, the arcuate shape has a larger valve opening area than other shapes, further improving safety.

[0022] In some embodiments of the present application, the arc angle enclosed by the arc wall is less than or equal to 180°.

[0023] In the above technical solution, the center of the end cap is not located in the groove, which ensures the structural strength of the end cap and leaves a space for installing other functional components on the end cap.

[0024] In some embodiments of the present application, the weakened portion and the arcuate wall have a first spacing distance.

[0025] In the above technical solution, the fragile portion and the arc-shaped wall are installed with a gap between them, and when the connection position between the arc-shaped wall and the bottom wall of the groove is not flat, a first gap distance is set, which makes it less likely that the fragile portion will be poorly formed, ensures good forming of the fragile portion, and ensures that the pressure relief mechanism will tear along the fragile portion.

[0026] In some embodiments of the present application, the ends of the weakened portion and the flat wall have a second separation distance.

[0027] In the above technical solution, when the edge of the end cap is extruded, the flat wall prevents deformation from being transmitted to the weak part, making the weak part less likely to tear. The structural strength of the end cap is high, and when the internal pressure of the battery cell does not reach the threshold, the pressure relief mechanism prevents tearing along the weak part, ensuring the normal use of the end cap.

[0028] In some embodiments of the present application, the arcuate wall and the edge of the end cap have a third separation distance.

[0029] In the above technical solution, the arc-shaped wall of the groove and the edge of the end cap are spaced apart to improve the structural strength of the edge corresponding to the arc-shaped wall of the end cap.

[0030] In some embodiments of the present application, the transition between the arcuate wall and the flat wall is an arc.

[0031] In the above technical solution, the corner at the connection point between the arc-shaped wall and the flat wall is rounded and chamfered, which alleviates the problem of stress concentration at the corner, prevents the end cap from being damaged by the corner of the groove when the edge of the end cap is extruded, and improves the structural strength of the end cap.

[0032] In some embodiments of the present application, a step surface is formed on a side wall of the groove, and the step surface extends along the circumferential direction of the groove.

[0033] When the edge of the end cap is extruded, the side wall above the step plane first resists deformation, and then the stress is transmitted by the step plane to the side wall and bottom wall below the step plane. Therefore, the above solution effectively alleviates the problem of the extrusion of the edge of the end cap causing damage to the weak part, and improves the structural strength of the end cap.

[0034] According to a second aspect, an embodiment of the present application provides an end cap assembly, the end cap assembly comprising: The device includes an end cap; a groove formed by recessing the surface of the end cap in the thickness direction, the bottom wall of the groove forming a pressure relief mechanism, the groove including an arc-shaped wall extending circumferentially of the end cap; and a fragile portion arranged to tear when the pressure relief mechanism is activated and installed to correspond to the shape of the arc-shaped wall.

[0035] The end cap assembly of the present application has high structural strength and can effectively and directionally open the valve to relieve pressure, improving battery safety.

[0036] In some embodiments of the present application, the weakened portion is arc-shaped, and the depth dimension of the weakened portion varies along the circumferential extension direction of the arc.

[0037] In the above technical solution, the installation format of the weak part matches the shape of the arc-shaped wall and is easy to process, and the depth dimension of the weak part varies along the circumferential extension direction of the arc, making it easy for the weak part to tear and the pressure relief mechanism to easily release the internal pressure of the battery cell.

[0038] In some embodiments of the present application, the end cap assembly further includes an electrode terminal, the electrode terminal including a flat first wall, the groove further including a flat wall connecting both ends of the arc-shaped wall, and the first wall being approximately parallel to the flat wall.

[0039] In the above technical solution, the first wall is approximately parallel to the flat wall; on the one hand, the distance between the groove and the electrode terminal is relatively small, which reduces the occupied space; on the other hand, it limits the tearing direction of the pressure relief mechanism and reduces the risk of the pressure relief mechanism coming into contact with the electrode terminal after being destroyed.

[0040] In some embodiments of the present application, the depth of the weakened portion gradually decreases along the direction of extension from the middle portion of the arcuate wall to both ends.

[0041] In the above technical solution, the depth of the weak part is determined by the above installation method, and when the pressure relief mechanism is activated, the weak part tears from the middle of the arc-shaped wall to both ends, restricting the tearing direction of the pressure relief mechanism and facilitating the pressure relief mechanism to release pressure.

[0042] In some embodiments of the present application, the end cap assembly further includes two through holes, which are used to attach the electrode terminals, and the depth of the weakened portion gradually decreases along one or both sides of a perpendicular bisector of the connection line of the two through holes in a direction away from the perpendicular bisector.

[0043] In the above technical solution, the deepest position of the weak part is at the perpendicular bisector, and when the pressure relief mechanism is activated, the weak part tears from the position corresponding to the perpendicular bisector in the direction away from the perpendicular bisector, facilitating the pressure relief mechanism to quickly release pressure and improving safety.

[0044] According to a third aspect, an embodiment of the present application provides a battery cell, the battery cell comprising: a case having an opening; and an end cap assembly as previously described, wherein the end cap seals the opening.

[0045] The end caps of the battery cell according to the present application are not easily broken, the entire structure is stable, and the pressure relief mechanism on the end caps can open the valve to relieve pressure effectively and in a directionally controllable manner, ensuring high safety.

[0046] In some embodiments of the present application, the recess is located on one side of the end cap that faces away from the case.

[0047] In the above technical solution, the groove is formed by recessing the outer surface of the end cap, so that the pressure relief mechanism is separated from the outer surface of the end cap, and the pressure relief mechanism is less likely to come into contact with other objects and be damaged.

[0048] According to a fourth aspect, an embodiment of the present application provides a battery, the battery including the end cap as described above or the end cap assembly as described above.

[0049] Since the battery according to the present application has the battery cells with relatively high safety as described above, the safety of the battery is relatively high and the performance is stable.

[0050] According to a fifth aspect, an embodiment of the present application provides a power consuming device, the power consuming device including a battery as described above.

[0051] The power consumption device according to the present application employs a battery that is highly safe and has stable performance, thereby realizing stable operation. [Brief explanation of the drawings]

[0052] In order to more clearly explain the technical solutions of the embodiments of the present application, the following briefly introduces the drawings that need to be used in the embodiments of the present application. It is obvious that the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on the drawings without exerting any creative efforts. [Figure 1] 1 is a structural schematic diagram of a vehicle according to an embodiment of the present application; [Figure 2] 1 is an exploded schematic view of a battery according to an embodiment of the present application. [Figure 3] 1 is a structural schematic diagram of a battery module according to an embodiment of the present application; [Figure 4] 1 is a structural schematic diagram of a battery cell according to an embodiment of the present application; [Figure 5] 1 is an exploded schematic view of a battery cell according to an embodiment of the present application. [Figure 6] FIG. 2 is a schematic plan view of an end cap according to one embodiment of the present application. [Figure 7] 7 is a cross-sectional view taken along the line AA in FIG. 6. [Figure 8] FIG. 8 is an enlarged view of part B in FIG. 7. [Figure 9] FIG. 2 is a perspective schematic view of an end cap according to an embodiment of the present application. [Figure 10] FIG. 10 is an enlarged view of part C in FIG. 9. [Figure 11] FIG. 2 is a top schematic view of an end cap assembly according to one embodiment of the present application. [Figure 12]1 is a top schematic view of an end cap assembly according to another embodiment of the present application. DETAILED DESCRIPTION OF THE INVENTION

[0053] The following detailed description will be given of the embodiments of the technical solution of the present application in conjunction with the drawings. The following embodiments are merely for the purpose of more clearly illustrating the technical solution of the present application, and are for illustrative purposes only and should not be construed as limiting the scope of protection of the present application.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art of this application, and the terms used herein are only for describing specific embodiments and are not intended to limit this application. The terms "comprises" and "having" and any variations thereof in the specification and claims of this application and the description of the drawings above are intended to cover a non-exclusive "comprise."

[0055] In the description of the embodiments of the present application, the technical terms "first," "second," etc. are merely used to distinguish between different objects, and should not be understood as indicating or suggesting the relative importance or implicitly specifying the number, specific order, or hierarchical relationship of the indicated technical features. In the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0056] The term "embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. Appearances of this phrase in various locations throughout the specification do not necessarily all refer to the same embodiment, nor are they mutually exclusive, independent, or alternative embodiments. Those skilled in the art can explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0057] In the description of the embodiments of this application, the term "and / or" is merely a relation that describes related objects and indicates that three relations may exist. For example, A and / or B may represent three cases: A alone, a combination of A and B, and B alone. In addition, the character " / " in this specification generally indicates that the related objects before and after are in an "or" relationship.

[0058] In describing the embodiments of the present application, unless otherwise specified, the term "plurality" refers to two or more (including two), and similarly, "sets" refers to two or more (including two sets), and "plurality" refers to two or more (including two).

[0059] In describing the embodiments of the present application, the orientations or positional relationships indicated by technical terms such as "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" are orientations or positional relationships shown in the drawings, and are intended merely to facilitate and simplify the description of the embodiments of the present application. They do not indicate or imply that the devices or elements referred to have a specific orientation or must be configured and operated in a specific orientation, and therefore should not be understood as limitations on the embodiments of the present application.

[0060] In the description of the embodiments of the present application, unless otherwise clearly defined or limited, the technical terms "attached," "connected," "connected," "fixed," etc. should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or an integral connection, a mechanical connection, an electrical connection, a direct connection, an indirect connection via an intermediate medium, internal communication between two elements, or an interactive relationship between two elements. Those skilled in the art may understand the specific meanings of the above terms in the embodiments of the present application according to specific circumstances.

[0061] The battery referred to in the embodiments of this application refers to a single physical module containing one or more battery cells to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. The battery generally includes a housing for packaging one or more battery cells. The housing can prevent liquids or other foreign objects from affecting the charging or discharging of the battery cells.

[0062] A battery cell includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode plate, a negative electrode plate, and a separator. The battery cell operates primarily through the movement of metal ions between the positive electrode plate and the negative electrode plate. The positive electrode plate includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The current collector without the positive electrode active material layer protrudes from the positive electrode active material layer coated current collector, and the current collector without the positive electrode active material layer is called a positive electrode tab. For example, in a lithium-ion battery, the positive electrode current collector may be made of aluminum, and the positive electrode active material may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode plate includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The current collector without the negative electrode active material layer protrudes from the current collector coated with the negative electrode active material layer, and the current collector without the negative electrode active material layer is called a negative electrode tab. The material of the negative electrode current collector may be copper, and the negative electrode active material may be carbon or silicon, etc. To ensure that a large current does not melt, multiple positive electrode tabs are stacked, and multiple negative electrode tabs are stacked. The separator may be made of PP or PE, etc. The electrode assembly may have a wound structure or a stacked structure, and the embodiments of the present application are not limited thereto. The development of battery technology requires simultaneous consideration of a wide range of design factors, such as performance parameters such as energy density, cycle life, discharge capacity, and charge / discharge ratio, as well as battery safety.

[0063] The main safety hazards for battery cells stem from the charging and discharging process, as well as from proper environmental temperature design. To effectively prevent unnecessary losses, battery cells typically have at least three protective measures. Specifically, these include at least a switching element, an appropriate separator material, and a pressure relief mechanism. The switching element is a device that can stop charging or discharging a battery when the temperature or resistance within the battery cell reaches a certain threshold. The separator separates the positive and negative electrodes. When the temperature rises to a certain value, the micropores on the separator, which are on the order of microns (and even nanometers), can automatically dissolve. This prevents metal ions from passing through the separator, stopping the internal reaction of the battery cell.

[0064] A pressure relief mechanism is an element or component that activates to release the internal pressure or temperature of a battery cell when the internal pressure or temperature reaches a predetermined threshold. The threshold design varies depending on design needs. The threshold may depend on one or more of the materials of the battery cell, including the positive electrode plate, the negative electrode plate, the electrolyte, and the separator. "Activation" as referred to in this application refers to the pressure relief mechanism operating or being activated to a certain state, thereby releasing the internal pressure and temperature of the battery cell. Operation by the pressure relief mechanism may include, but is not limited to, rupturing, crushing, tearing, or opening at least a portion of the pressure relief mechanism. When the pressure relief mechanism is activated, high-temperature and high-pressure materials inside the battery cell are discharged as discharged material from the activated location. In this manner, pressure relief can be generated in the battery cell when the pressure or temperature is controllable, thereby avoiding potentially more serious accidents. The emissions from battery cells referred to in this application include, but are not limited to, electrolyte, dissolved or split positive and negative electrodes, separator fragments, high temperature and pressure gases generated by reactions, flames, etc.

[0065] The pressure relief mechanism on a battery cell has an important impact on battery safety. For example, when a short circuit or overcharging occurs, thermal runaway may occur inside the battery cell, causing a sudden increase in pressure or temperature. In such cases, the pressure relief mechanism can be activated to release the internal pressure and temperature, thereby preventing the battery cell from exploding or catching fire. The pressure relief mechanism can take the form of an explosion-proof valve, air valve, pressure relief valve, or safety valve, and can specifically employ a pressure- or temperature-sensitive element or structure. That is, when the internal pressure or temperature of the battery cell reaches a predetermined threshold, the pressure relief mechanism operates, or a fragile structure in the pressure relief mechanism breaks, thereby forming a through hole or channel for releasing the internal pressure or temperature.

[0066] Currently, a pressure relief channel is typically installed on the end cap, and a pressure relief mechanism is connected to the end cap and seals the pressure relief channel. However, conventional battery cells still have safety risks after the pressure relief mechanism is installed, such as the risk of debris flying out when the pressure relief mechanism is activated and the risk of materials (such as high-temperature, high-pressure gas) being released when the pressure relief mechanism is activated, as well as the risk of battery cell leakage. Further research has found that the need to open a channel for the pressure relief mechanism in the end cap reduces the structural strength, making the end cap more susceptible to damage and leakage. Furthermore, the connection between the pressure relief mechanism and the end cap is more likely to have connection defects, leading to leakage due to imperfect connections, such as bubbles and cracks at the welded seam between the pressure relief mechanism and the end cap.

[0067] In view of this, in order to solve the safety issues caused by the operation of the pressure relief mechanism and the safety issues caused by leakage, the present application provides an end cap, the surface of which is recessed along the thickness direction to form a groove, the bottom wall of which forms the pressure relief mechanism, a weak part disposed on the pressure relief mechanism, the pressure relief mechanism being arranged to tear along the weak part when the internal pressure of the battery cell reaches a threshold value, two through holes for mounting electrode terminals formed on the end cap, the perpendicular bisector of the connecting lines of the two through holes intersects with the weak part, and the depth of the weak part gradually decreases along one or both sides of the perpendicular bisector of the connecting lines of the two through holes in the direction away from the perpendicular bisector.

[0068] In the end cap of the present application, a groove is installed on the end cap, so that the thickness of the bottom wall of the groove is thinner than that of the end cap, and the relatively thin bottom wall of the groove serves as a pressure relief mechanism. This pressure relief mechanism is molded directly on the end cap, so there is no need to connect the pressure relief mechanism to the end cap, eliminating the problem of connection defects and the resulting leakage problem.

[0069] A weakened portion is further provided on the pressure relief mechanism to further reduce the thickness of the pressure relief mechanism at the weakened portion. The weakened portion may be a recess formed on the pressure relief mechanism, which is used to reduce the thickness of the pressure relief mechanism (i.e., the thickness of the bottom wall of the recessed portion). The recess may be a notch, or a groove formed on the pressure relief mechanism by extrusion, punching, integral casting, etc. While the entire weakened portion of the pressure relief mechanism in prior art is uniform in depth, the depth of the weakened portion in the present application varies, with the greatest depth only at the intersection of the weakened portion and the perpendicular bisector of the connecting line of the two through holes, and the depth of the weakened portion gradually decreasing in the direction away from this perpendicular bisector, thereby gradually increasing the thickness of the pressure relief mechanism at the weakened portion, improving the structural strength of the pressure relief mechanism and the end cap, and making the end cap less likely to break or leak when the internal pressure of the battery cell is below the threshold.

[0070] When the internal pressure of the battery cell increases, the end cap expands and deforms, and the perpendicular bisector of the connecting line of the two through-holes is the center line of the stress deformation of the end cap, and the stress of the end cap is relatively concentrated on the center line of the stress deformation. By locating the maximum depth position of the weak part of the pressure relief mechanism on the perpendicular bisector of the two through-holes, when the internal pressure of the battery cell reaches the threshold, the maximum stress received by the end cap acts on the maximum depth position of the weak part, ensuring that the weak part of the pressure relief mechanism tears at the maximum depth position. After the weak part tears, the internal pressure of the battery cell acts to make the pressure relief mechanism continue to tear along the weak part, increasing the opening area and achieving effective pressure relief, ensuring the safety of the battery.

[0071] Furthermore, by setting the depth of the weak part, the initial tear position and tear direction of the weak part can be determined, and thereby the opening direction of the pressure relief mechanism can be determined. This allows for advance measures to be taken, mitigating safety issues caused by flying debris and protruding emissions when the pressure relief mechanism is activated, and further improving the safety of the battery.

[0072] The end caps disclosed in the embodiments of the present application are used with battery cells, and the battery cells may include, but are not limited to, lithium ion secondary batteries, lithium ion primary batteries, lithium-sulfur batteries, sodium lithium ion batteries, sodium ion batteries, magnesium ion batteries, etc. The battery cells may be cylindrical, flat, rectangular, or have other shapes, etc., and the embodiments of the present application are not limited to these.

[0073] The battery cells disclosed in the present embodiment may be used in power consuming devices such as, but not limited to, vehicles, ships, and aircraft, etc. The battery cells and batteries disclosed in the present application may be used to configure the power supply system of the power consuming devices, which is advantageous in mitigating safety risks caused by battery leakage and charging / discharging, and improving the safety of battery performance and the service life of the battery.

[0074] An embodiment of the present application provides a power-consuming device that uses a battery as a power source, and the power-consuming device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, an electric bike, an electric car, a steamship, a spacecraft, etc. Here, the electric toy may include a stationary or mobile electric toy, such as a game console, an electric car toy, an electric steamship toy, and an electric airplane toy, and the spacecraft may include an airplane, a rocket, a space shuttle, a spaceship, etc.

[0075] In the following embodiment, for ease of explanation, an example will be described in which one power consuming device in one embodiment of the present application is a vehicle.

[0076] For example, as shown in FIG. 1, FIG. 1 illustrates a vehicle 1000 according to an embodiment of the present application. The vehicle 1000 may be a fuel oil vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a range extender vehicle, etc. A battery 100, a controller 300, and a motor 200 may be installed inside the vehicle 1000. The controller 300 is used to control the battery 100 to power the motor 200. For example, the battery 100 may be installed at the bottom, front, or rear of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as an operating power source for the vehicle 1000, and may be used for the circuit system of the vehicle 1000, for example, for starting the vehicle 1000, navigation, and operating power consumption needs during driving. In another embodiment of the present application, the battery 100 can not only be the operating power source for the vehicle 1000, but can also be the driving power source for the vehicle 1000, providing driving power to the vehicle 1000 in place of, or in place of, fuel oil or natural gas.

[0077] To meet various power consumption needs, the battery 100 may include multiple battery cells 1, where the multiple battery cells 1 may be connected in series, parallel, or series-parallel, where series-parallel connection is a combination of series and parallel connections. The battery 100 may also be referred to as a battery 100 pack. Alternatively, referring to FIGS. 2 and 3 , multiple battery cells 1 may first be connected in series, parallel, or series-parallel to form a battery module 102, and the multiple battery modules 102 may then be connected in series, parallel, or series-parallel to form the battery 100. That is, the multiple battery cells 1 may directly form the battery 100, or the battery module 102 may first be formed, and the battery 100 may then be formed using the battery module 102.

[0078] The battery 100 may include a plurality of battery cells 1. The battery 100 may further include a housing 101 (also referred to as a cover), the interior of which has a hollow structure, and the plurality of battery cells 1 are housed within the housing 101. The housing 101 may include two housing portions (which may refer to FIG. 2 ), here referred to as a first portion 1011 and a second portion 1012, respectively, and the first portion 1011 and the second portion 1012 are engaged with each other. The shapes of the first portion 1011 and the second portion 1012 may be determined according to the shape of the combination of the plurality of battery cells 1, and both the first portion 1011 and the second portion 1012 may have an opening. For example, the first part 1011 and the second part 1012 may both be hollow rectangular parallelepipeds with only one open side, with the opening of the first part 1011 and the opening of the second part 1012 positioned opposite each other, and the first part 1011 and the second part 1012 engaged with each other to form the housing 101 having a sealed chamber. One of the first part 1011 and the second part 1012 may be a rectangular parallelepiped with an opening, and the other may have a cover plate structure that seals the opening of the rectangular parallelepiped. A plurality of battery cells 1 are combined by being connected in parallel, series, or series-parallel with each other, and then placed in the housing 101 formed after the first part 1011 and the second part 1012 are engaged with each other.

[0079] Optionally, the battery 100 may further include other structures. For example, the battery 100 may further include busbar members, which are used to realize electrical connections between the multiple battery cells 1, such as parallel connections, series connections, or series-parallel connections. Specifically, the busbar members can realize electrical connections between the battery cells 1 by connecting the electrode terminals of the battery cells 1. Furthermore, the busbar members can be fixed to the electrode terminals of the battery cells 1 by welding. Electrical energy from the multiple battery cells 1 can further be conducted through the housing 101 by a conductive mechanism. Optionally, the conductive mechanism may also belong to the busbar members.

[0080] Hereinafter, one of the battery cells 1 will be described in detail. As shown in FIGS. 4 and 5, the battery cell 1 includes an electrode assembly 11, a case 12, and an end cap assembly 13.

[0081] The electrode assembly 11 is a component that generates an electrochemical reaction within the battery cell 1. One battery cell 1 may include one or more electrode assemblies 11. The electrode assembly 11 is primarily formed by winding or stacking positive and negative electrode plates, and typically has a separator between the positive and negative electrode plates. The portions of the positive and negative electrode plates that contain active material constitute the main body of the electrode assembly 11, and the portions of the positive and negative electrode plates that do not contain active material constitute the tabs, respectively. The positive and negative electrode tabs may both be located at one end of the main body, or may be located at both ends of the main body. During the charge and discharge process of the battery 100, the positive and negative electrode active materials react with the electrolyte, and the tabs are connected to the electrode terminals 132 to form a current circuit.

[0082] The case 12 is an assembly that is fitted with an end cap 131 to form an internal environment for the battery cell 1. The formed internal environment may be used to accommodate the electrode assembly 11, electrolyte, and other components. The case 12 and the end cap 131 may be separate components, or an opening 121 may be provided on the case 12, and the end cap 131 may be placed over the opening 121 to form the internal environment for the battery cell 1. Alternatively, the end cap 131 and the case 12 may be integrated. Specifically, the end cap 131 and the case 12 may first form a common connection surface before other components are inserted into the case, and the end cap 131 is then placed over the case 12 when the interior of the case 12 needs to be packaged. The case 12 may have various shapes and sizes, such as a rectangular parallelepiped, cylindrical, or hexagonal prism. Specifically, the shape of the case 12 may be determined depending on the specific shape and size of the electrode assembly 11. The case 12 may be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application is not particularly limited thereto.

[0083] The end cap assembly 13 is a component that fits into the opening 121 of the case 12 to isolate the internal environment of the battery cell 1 from the external environment. The end cap assembly 13 includes an end cap 131, electrode terminals 132, a pressure relief mechanism 134, and other functional components. Here, the end cap 131 is used to connect to the case 12 to seal the opening 121. Alternatively, the shape of the end cap 131 may be adapted to match the shape of the case 12 so that it fits into the case 12. Alternatively, the end cap 131 may be made of a material (e.g., aluminum alloy) with a certain hardness and strength. In this way, the end cap 131 is less likely to deform when extruded or impacted, and the battery cell 1 may have higher structural strength and improved safety performance. The end cap 131 may be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application are not particularly limited thereto. In some embodiments, an insulating member may be further installed inside the end cap 131, and the insulating member may be used to separate the end cap 131 from the electrical connection members inside the case 12 to reduce the risk of short circuits. Illustratively, the insulating member may be made of plastic, rubber, or the like. Electrode terminals 132 may be installed in the end cap 131 and may be used for electrical connection with tabs of the electrode assembly 11 so as to be used for outputting or inputting electrical energy to or from the battery cell 1. A pressure relief mechanism 134 is installed in the end cap 131 and is used to release internal pressure when the internal pressure or temperature of the battery cell 1 reaches a threshold.

[0084] According to some embodiments of the present application, the present application provides an end cap 131 for use with a battery cell 1 (shown in FIG. 5), as shown in Figures 6, 7, and 8. The end cap 131 is provided with a groove 133 and two through holes 135. The groove 133 is formed by recessing the surface of the end cap 131 in the thickness direction, and the bottom wall of the groove 133 forms a pressure relief mechanism 134. A weak part 1341 is provided on the pressure relief mechanism 134, and the pressure relief mechanism 134 is arranged to tear along the weak part 1341 when the internal pressure of the battery cell 1 reaches a threshold. The two through holes 135 penetrate the end cap 131 and are used to attach electrode terminals 132. The depth of the weak part 1341 gradually decreases along one or both sides of a perpendicular bisector α of the connecting line of the two through holes 135 in a direction away from the perpendicular bisector α.

[0085] As shown in the figure, the β direction is the thickness direction of the end cap, and the recess direction of the recessed groove 133 and the depth direction of the fragile portion 1341 are both along the thickness direction β of the end cap.

[0086] The pressure relief mechanism 134 is used to release the internal pressure of the battery cell 1, and the pressure relief mechanism 134 can release pressure spontaneously or passively. Optionally, the pressure relief mechanism 134 releases pressure passively, for example, the pressure relief mechanism 134 is arranged to tear along the weakened portion 1341 when the internal pressure of the battery cell 1 reaches a threshold value.

[0087] 7, by providing groove 133 on end cap 131, the thickness of the bottom wall of groove 133 is thinner than the thickness of end cap 131, and this thinner bottom wall of groove 133 serves as pressure relief mechanism 134, that is, when the internal pressure of battery cell 1 reaches a threshold, the bottom wall of groove 133 is broken to release the internal pressure. Groove 133 may be formed on end cap 131 by cutting or other methods, or may be integrally cast with end cap 131. Further, groove 133 may be formed together with end cap 131 by one-time stamping, or may be formed by stamping groove 133 out of raw material and then stamping out end cap 131.

[0088] As shown in FIG. 8 , the fragile portion 1341 is a recess formed on the pressure relief mechanism 134, i.e., another groove 133 (hereinafter referred to as the second groove) formed on the bottom wall of the groove 133. The bottom wall of the groove 133 has a surface recessed along the thickness direction β of the end cap to form the second groove, which reduces the thickness of the bottom wall of the groove 133 (i.e., reduces the thickness of the pressure relief mechanism 134). The second groove may be a notch formed on the surface of the pressure relief mechanism 134, or may be formed on the pressure relief mechanism 134 by secondary punching, or may be integrally formed during casting of the end cap 131. The fragile portion 1341 is used to define a preferential failure position of the pressure relief mechanism 134. When the internal pressure of the battery cell 1 reaches a threshold, the pressure relief mechanism 134 will preferentially fail from the fragile portion 1341 to release the internal pressure.

[0089] Two through holes 135 on the end cap 131 penetrate the end cap 131 along the thickness direction β of the end cap, and two electrode terminals 132 are attached to the two through holes 135, respectively. The connection points between each electrode terminal 132 and the through holes 135 are sealed to prevent leakage. Optionally, an insulating member is installed at the connection points between each electrode terminal 132 and the through holes 135 to prevent charging of the end cap 131, thereby reducing the safety risk of a short circuit due to charging of the end cap 131. The polarities of the two electrode terminals 132 may be the same or different.

[0090] When the internal pressure of the battery cell 1 increases, the end cap 131 is extruded and thus expands and deforms. The structural strength of the through-holes 135 of the end cap 131 is relatively low, and the perpendicular bisector α of the connecting line of the two through-holes 135 is the center line of stress deformation of the end cap 131. That is, the stress of the end cap 131 is relatively concentrated on the perpendicular bisector α of the connecting line of the two through-holes 135. The perpendicular bisector α refers to the perpendicular bisector of a line segment, i.e., the perpendicular line drawn through the midpoint of the connecting line of the two through-holes 135. The two through-holes 135 may have a circular shape, and in other embodiments, the two through-holes 135 may have other shapes. The connecting line of the two through-holes 135 refers to the connecting line of the centroids of the two through-holes 135. For example, when the two through-holes 135 are circular, the connecting line of the two through-holes 135 is the connecting line of the centers of the circles of the two through-holes 135.

[0091] The perpendicular bisector α (hereinafter referred to as the perpendicular bisector α) of the connecting line of the two through holes 135 passes through the weak portion 1341, i.e., the perpendicular bisector α intersects with the weak portion 1341, and there is an intersection between the perpendicular bisector α and the weak portion 1341. The weak portion 1341 is positioned so that its depth is greatest at the intersection and its depth decreases along the direction away from the perpendicular bisector α to one or both sides of the perpendicular bisector α. In other words, the further away from the intersection between the weak portion 1341 and the perpendicular bisector α along the extension direction of the weak portion 1341, the smaller the depth of the weak portion 1341 becomes, and the greater the thickness remaining after being thinned by the weak portion 1341 of the pressure relief mechanism 134.

[0092] The pressure relief mechanism 134 is directly formed on the end cap 131, and a weakened portion 1341 with a gradually varying depth is provided on the pressure relief mechanism 134. The deepest point of the weakened portion 1341 is located on the perpendicular bisector α of the connecting line of the two through holes 135. This ensures that the strength of the entire end cap 131 is relatively high, and there are no connection defects between the pressure relief mechanism 134 and the end cap 131. This effectively alleviates the leakage problem, and the pressure relief mechanism 134 on the end cap 131 does not tear from the specific deepest point of the weakened portion 1341. This further ensures that the pressure relief mechanism 134 operates effectively under internal pressure, and the pressure relief mechanism 134 further tears along the fragile portion 1341 under the internal pressure of the battery cell 1, expanding the valve opening area. If the initial breaking position and subsequent tearing direction of the pressure relief mechanism 134 are limited, the valve opening position and direction of the pressure relief mechanism 134 can be controlled, making it easier to prepare the pressure relief mechanism 134 in advance, for example, to install protection in the release direction of the pressure relief mechanism 134, thereby improving the safety of the battery 100. The channel connecting the inside and outside of the battery cell 1 formed after the pressure relief mechanism 134 tears is used to release waste, and the valve opening area referred to in this application refers to the flow cross-sectional area of ​​this channel.

[0093] According to some embodiments of the present application, the perpendicular bisector α of the connecting line of the two through holes 135 passes through the center of the weakened portion 1341 .

[0094] As described above, the extension direction of the fragile portion 1341 and the perpendicular bisector α form a certain angle, and the intersection of the fragile portion 1341 and the perpendicular bisector α is at the midpoint of the extension direction of the fragile portion 1341.

[0095] Since the deepest position of the weak part 1341 is in the center, when the internal pressure of the battery cell 1 reaches a threshold, the pressure relief mechanism 134 synchronously tears from the center to both sides along the weak part 1341, the pressure relief mechanism 134 opens quickly, and the pressure in the battery cell 1 is quickly relieved, improving safety.

[0096] According to some embodiments of the present application, the weakened portion 1341 is symmetrical about the perpendicular bisector α.

[0097] The intersection of the weakened portion 1341 and the perpendicular bisector α is at the midpoint of the extension direction of the weakened portion 1341, the extension direction of the weakened portion 1341 is perpendicular to the perpendicular bisector α, and the weakened portion 1341 is symmetrical with respect to the perpendicular bisector α.

[0098] Because the perpendicular bisector α is a stress concentration line, the stress distribution on both sides of the stress concentration line is close, and the forces received by the weak part 1341 on both sides of the perpendicular bisector α are consistent, ensuring that the pressure relief mechanism 134 tears from the center to both sides along the weak part 1341, further controlling the opening direction of the pressure relief mechanism 134 and improving safety.

[0099] According to some embodiments of the present application, the groove 133 is symmetrical with respect to the perpendicular bisector α.

[0100] By making the groove 133 symmetrical about the perpendicular bisector α, it is further ensured that the stress concentration position of the end cap 131 is on the perpendicular bisector α, and it is further ensured that the pressure relief mechanism 134 breaks from the intersection of the weakened portion 1341 and the perpendicular bisector α, thereby controlling the valve opening position. When the groove 133 is symmetrical about the perpendicular bisector α and the weakened portion 1341 is symmetrical about the perpendicular bisector α, the pressure relief mechanism 134 is symmetrical about the perpendicular bisector α, and the structural strength and stress-bearing capacity of the pressure relief mechanism 134 on both sides of the perpendicular bisector α are consistent. This ensures that when the internal pressure of the battery cell 1 reaches a threshold, the pressure relief mechanism 134 opens synchronously from the intersection of the weakened portion 1341 and the perpendicular bisector α to both sides of the perpendicular bisector α, resulting in more accurate valve opening direction, faster valve opening speed, and higher safety.

[0101] According to some embodiments of the present application, the end cap 131 is circular, the perpendicular bisector α passes through the center of the end cap 131 , and the weakened portion 1341 extends along the circumferential direction of the end cap 131 .

[0102] 6 , the two through holes 135 are symmetrically arranged on the circular end cap 131, with the perpendicular bisector α of the connecting line between the two through holes 135 passing through the center of the circular end cap 131, and the two through holes 135 being symmetrical with respect to the perpendicular bisector α. The weakened portion 1341 extends along the circumferential direction of the end cap 131, i.e., the weakened portion 1341 extends along an arcuate direction, and the center of the arcuate circle overlaps with the center of the circular end cap 131. The overlap referred to in this application may be a complete overlap, or may be a state in which the center of the arcuate circle is near the center of the end cap 131, resulting in an approximate overlap.

[0103] With the above-mentioned arrangement, the entire end cap 131 is symmetrical with respect to the perpendicular bisector α, and the structural strength and bearing capacity of the two parts of the end cap 131 on both sides of the perpendicular bisector α are consistent. This ensures that the stress of the end cap 131 is concentrated on the perpendicular bisector α, which further ensures that the end cap 131 will first tear from the deepest position of the weak part 1341 on the perpendicular bisector α, and further ensures the opening direction of the pressure relief mechanism 134.

[0104] When the circular end cap 131 is deformed by internal pressure, the deformation at the center (circle center) is relatively large and the deformation at the edge is relatively small. Because the weakened portion 1341 extends along the circumferential direction of the end cap 131, the weakened portion 1341 is relatively closer to the edge of the end cap 131 and relatively farther from the center of the end cap 131. Therefore, when the weakened portion 1341 approaches the edge of the end cap 131 where deformation is relatively small, the weakened portion 1341 needs to be relatively deep to ensure that it will tear with the same valve-opening pressure. Because the overall thickness of the end cap 131 is small, the pressure relief mechanism 134 and the weakened portion 1341 are more precise and have higher requirements for processing accuracy. Therefore, by making the weakened portion 1341 relatively deep, the processing difficulty can be effectively reduced.

[0105] According to some embodiments of the present application, the groove 133 includes an arc-shaped wall 1331 and a flat wall 1332 , the arc-shaped wall 1331 and the flat wall 1332 are mutually surrounding, and the arc-shaped wall 1331 extends along the circumferential direction of the end cap 131 .

[0106] 6 , the projection of the arc-shaped wall 1331 onto the end cap 131 is an arc, and the center of the arc overlaps with the center of the circular end cap 131. The overlap referred to in this application may be a complete overlap, or a state in which the center of the arc is near the center of the end cap 131, resulting in an approximate overlap. The projection of the flat wall 1332 onto the end cap 131 is a straight line segment, and both ends of the straight line segment are connected to both ends of the arc, forming an arc. That is, the projection shape of the groove 133 onto the end cap 131 is an arc, or the shape of the groove 133 is an arc.

[0107] When processing the fragile portion 1341, for example, by engraving, punching, or other methods, on the pressure relief mechanism 134, the arc-shaped wall 1331 is used as a reference and the fragile portion 1341 is processed along the arc-shaped wall 1331, making processing easy.

[0108] After the pressure relief mechanism 134 is torn along the weak portion 1341, the pressure relief mechanism 134 is connected to the flat wall 1332 to prevent the pressure relief mechanism 134 from flying out after being broken, and the opening direction of the pressure relief mechanism 134 faces the edge of the end cap 131, limiting the discharged material to escape toward the edge of the end cap 131.

[0109] In other embodiments, the groove 133 may have other shapes, such as a waist shape. The waist shape has two arcuate walls 1331 extending along the circumferential direction of the end cap 131, with one arcuate wall 1331 closer to the center of the end cap 131 and the other arcuate wall 1331 closer to the edge of the end cap 131. Optionally, a weakened portion 1341 may be machined along the arcuate wall 1331 closer to the edge of the end cap 131. This allows the pressure relief mechanism 134 to remain connected to the arcuate wall 1331 closer to the center of the end cap 131 after it tears along the weakened portion 1341, preventing it from flying out after being broken. Furthermore, the opening direction of the pressure relief mechanism 134 faces the edge of the end cap 131, limiting the release of waste materials toward the edge of the end cap 131.

[0110] When the length of the fragile portion 1341 is constant, the opening area of ​​the arcuate portion is larger than that of the waisted portion, further improving safety. When the opening area is constant, the arcuate portion extends less along the edge of the end cap 131 than that of the waisted portion, so the effect of the groove 133 on the structural strength of the end cap 131 is relatively small, and the structural strength of the end cap 131 with the arcuate portion installed is higher.

[0111] According to some embodiments of the present application, the arc angle γ enclosed by the arc wall 1331 is less than or equal to 180°.

[0112] Referring again to FIG. 6, the figure shows the arc angle γ enclosed by the arc-shaped wall 1331. By making the arc angle γ≦180°, the center position of the end cap 131 is not within the groove 133, which ensures the structural strength of the end cap 131 and leaves space for other functional components to be installed on the end cap 131.

[0113] According to some embodiments of the present application, the weakened portion 1341 and the arcuate wall 1331 have a first spacing distance L1.

[0114] 6 again, the weakened portion 1341 is not installed closely to the connection position between the arc-shaped wall 1331 and the bottom wall of the recessed groove 133, but has a first gap L1 between the weakened portion 1341 and the arc-shaped wall 1331. Optionally, the first gap L1 is greater than 1 mm.

[0115] When the connection position between the arc-shaped wall 1331 and the bottom wall of the groove 133 is not flat, the first gap distance L1 is set, which makes it less likely to affect the shape of the fragile portion 1341, avoids the problem of poor molding of the fragile portion 1341, ensures good molding of the fragile portion 1341, and guarantees that the pressure relief mechanism 134 will tear along the fragile portion 1341.

[0116] The first gap distance L1 allows the groove 133 to have a certain degree of processing error, and prevents the weak portion 1341 from being positioned outside the groove 133 due to the processing error.

[0117] According to some embodiments of the present application, the ends of the weakened portion 1341 and the flat wall 1332 have a first spacing distance L1.

[0118] 6, both ends of the fragile portion 1341 do not extend to the connection between the flat wall 1332 and the bottom wall of the recessed groove 133, and there is a second gap distance L2 between both ends of the fragile portion 1341 and the flat wall 1332. Optionally, the second gap distance L2 is ≥ 0.5 mm.

[0119] Since there is a second gap distance L2 between both ends of the fragile portion 1341 and the flat wall 1332, when the edge of the end cap 131 is pushed out, the flat wall 1332 is less likely to transmit deformation to the fragile portion 1341, making the fragile portion 1341 less likely to tear. The structural strength of the end cap 131 is high, and when the internal pressure of the battery cell 1 does not reach the threshold, the pressure relief mechanism 134 is less likely to tear unexpectedly along the fragile portion 1341.

[0120] According to some embodiments of the present application, the arcuate wall 1331 and the edge of the end cap 131 have a third spacing distance L3.

[0121] 6, a third gap L3 is provided between the arc-shaped wall 1331 of the groove 133 and the edge of the end cap 131 to ensure the structural strength of the edge corresponding to the arc-shaped wall 1331 of the end cap 131. Optionally, the third gap L3 is greater than 3 mm.

[0122] According to some embodiments of the present application, the transition between the arcuate wall 1331 and the flat wall 1332 is an arc.

[0123] Referring again to FIG. 6, the corners at the junctions of the arcuate wall 1331 and the flat wall 1332 are rounded and chamfered to achieve an arcuate transition between the arcuate wall 1331 and the flat wall 1332 .

[0124] By arranging the arc-shaped wall 1331 and the flat wall 1332 at an arc transition, the problem of stress concentration at the corner between the arc-shaped wall 1331 and the flat wall 1332 is alleviated, and when the edge of the end cap 131 is extruded, the end cap 131 is prevented from being damaged at the corner of the groove 133, thereby improving the structural strength of the end cap 131.

[0125] According to some embodiments of the present application, a step surface 1333 is formed on the side wall of the groove 133 , and the step surface 1333 extends along the circumferential direction of the groove 133 .

[0126] 9 and 10 , the step surface 1333 is perpendicular to the arcuate wall 1331 and the flat wall 1332 and divides the side wall formed by the arcuate wall 1331 and the flat wall 1332 into upper and lower parts in the thickness direction β of the end cap, where the upper side wall and the lower side wall are offset from each other, and the opening area of ​​the groove 133 is larger than the bottom wall area of ​​the groove 133. In other embodiments, the opening area of ​​the groove 133 may be smaller than the bottom wall area of ​​the groove 133.

[0127] By installing the step surface 1333, when the edge of the end cap 131 is subjected to a pushing force toward the center of the circle, the upper side wall first resists deformation, and then the stress is transmitted by the step surface 1333 to the lower side wall and then to the bottom wall, effectively mitigating the impact of the edge of the end cap 131 being pushed out and affecting the weak part 1341, preventing the weak part 1341 from being destroyed when the internal pressure of the battery cell 1 does not reach the threshold, and improving the structural strength of the end cap 131.

[0128] 11 , some embodiments of the present application provide an end cap assembly 13, which includes an end cap 131 and electrode terminals 132 according to any one of the above solutions. Two electrode terminals 132 are installed in two through-holes 135 of the end cap 131 to extract or input electrical energy from or into the battery cell 1.

[0129] 11 , some embodiments of the present application provide an end cap assembly 13, which includes an end cap 131, a groove 133, and a weakened portion 1341. The groove 133 is formed by recessing the surface of the end cap 131 along the thickness direction β, and the bottom wall of the groove 133 forms a pressure relief mechanism 134. The groove 133 includes an arc-shaped wall 1331 extending along the circumferential direction of the end cap 131. The weakened portion 1341 is arranged to tear when the pressure relief mechanism 134 is activated, and the weakened portion 1341 is installed to correspond to the shape of the arc-shaped wall 1331.

[0130] The end cap 131 has a circular outline, the arc-shaped wall 1331 extends circumferentially around the end cap 131, the pressure relief mechanism 134 is formed on the bottom wall of the groove 133, and the weak portion 1341 is installed on the pressure relief mechanism 134, and the weak portion 1341 is installed to correspond to the shape of the arc-shaped wall 1331.

[0131] The fragile portion 1341 is a recess formed on the pressure relief mechanism 134, i.e., a separate groove (hereinafter referred to as the second groove for ease of distinction) formed on the bottom wall of the groove 133. The surface of the bottom wall of the groove 133 is recessed along the thickness direction β of the end cap 131 to form the second groove. The second groove reduces the thickness of the bottom wall of the groove 133 (i.e., reduces the thickness of the pressure relief mechanism 134). The fragile portion 1341 may be a notch formed on the surface of the pressure relief mechanism 134, may be formed on the pressure relief mechanism 134 by secondary punching, or may be integrally formed during casting of the end cap 131. The fragile portion 1341 is used to define a preferential breaking position of the pressure relief mechanism 134. Optionally, when the internal pressure of the battery cell 1 reaches a threshold, the pressure relief mechanism 134 is activated and the pressure relief mechanism 134 preferentially tears from the fragile portion 1341 to release the internal pressure.

[0132] The pressure relief mechanism 134 tears along the fragile portion 1341, expanding the opening area. If the initial breaking position and subsequent tearing direction of the pressure relief mechanism 134 are limited, the opening position and direction of the pressure relief mechanism 134 can be controlled, facilitating preparation of the pressure relief mechanism 134 in advance, for example, providing protection in the release direction of the pressure relief mechanism 134, thereby improving the safety of the battery 100. The channel connecting the inside and outside of the battery cell 1 formed after the pressure relief mechanism 134 tears is used to release effluent, and the opening area referred to in this application refers to the flow cross-sectional area of ​​this channel.

[0133] The end cap assembly 13 of the present application has high structural strength and can effectively and directionally open the valve to relieve pressure, thereby improving the safety of the battery 100.

[0134] According to some embodiments of the present application, as shown in FIG. 11, the weakened portion 1341 has an arc shape, and the depth dimension of the weakened portion 1341 varies along the circumferential extension direction of the arc shape.

[0135] The weakened portion 1341 is arc-shaped and is provided to correspond to the shape of the arc-shaped wall 1331, facilitating processing and forming.

[0136] The depth dimension of the weakened portion 1341 varies along the arcuate circumferential extension direction, allowing the weakened portion to tear in an arcuate shape, facilitating the pressure relief mechanism to release the internal pressure of the battery cell.

[0137] According to some embodiments of the present application, as shown in FIG. 11 , the end cap assembly 13 further includes an electrode terminal 132, the electrode terminal 132 including a flat first wall 1321, the groove 133 further including a flat wall 1332 connecting both ends of the arc-shaped wall 1331, and the first wall 1321 being approximately parallel to the flat wall 1332.

[0138] The first wall 1321 is one wall of the electrode terminal 132, and this wall is approximately parallel to the flat wall 1332 of the groove 133. The first wall 1321 being approximately parallel to the flat wall 1332 means that the first wall 1321 is parallel to the flat wall 1332, or that the angle between the first wall 1321 and the flat wall 1332 is relatively small (for example, less than 5°).

[0139] The first wall 1321 may be a wall that is closer to the groove 133 of the electrode terminal 132 , and the first wall 1321 is closer to the groove 133 than the other walls of the electrode terminal 132 .

[0140] The first wall 1321 is approximately parallel to the flat wall 1332. On the one hand, the distance between the groove 133 and the electrode terminal 132 is relatively small, which reduces the space occupied; on the other hand, it limits the tearing direction of the pressure relief mechanism 134 and reduces the risk of the pressure relief mechanism 134 coming into contact with the electrode terminal 132 after being destroyed.

[0141] According to some embodiments of the present application, the depth of the weakened portion 1341 gradually decreases along the direction of extension from the middle portion of the arcuate wall 1331 to both ends.

[0142] In the above technical solution, the depth of the fragile portion 1341 is set in the above installation manner, and when the pressure relief mechanism 134 is activated, the fragile portion 1341 tears from the middle to both ends of the arc-shaped wall 1331, restricting the tearing direction of the pressure relief mechanism 134 and facilitating the pressure relief mechanism 134 from releasing pressure.

[0143] According to some embodiments of the present application, as shown in Figures 6 and 11, the end cap assembly 13 further includes two through holes 135, which are used to attach the electrode terminals 132, and the depth of the weakened portion 1341 gradually decreases along one or both sides of the perpendicular bisector α of the connection line of the two through holes 135 in the direction away from the perpendicular bisector α.

[0144] The depth of the fragile portion 1341 may gradually decrease along one side of the perpendicular bisector α of the connecting line of the two through holes 135, in a direction away from the perpendicular bisector α, or the depth of the fragile portion 1341 may gradually decrease along both sides of the perpendicular bisector α of the connecting line of the two through holes 135, in a direction away from the perpendicular bisector α.

[0145] In the above technical solution, the deepest position of the fragile part 1341 is at the perpendicular bisector α, and when the pressure relief mechanism 134 is activated, the fragile part 1341 tears from the position corresponding to the perpendicular bisector α in the direction away from the perpendicular bisector α, facilitating the pressure relief mechanism 134 to quickly release pressure and improving safety.

[0146] According to some embodiments of the present application, as shown in Figures 4, 5, and 11, the embodiments of the present application provide a battery cell 1, which includes a case 12 and the aforementioned end cap assembly 13. An opening is provided on the case 12, and an end cap 131 seals the opening.

[0147] According to some embodiments of the present application, the recess 133 is located on one side of the end cap 131 that faces away from the case 12 .

[0148] The groove 133 is formed by recessing the outer surface of the end cap 131, so that the pressure relief mechanism 134 is separated from the outer surface of the end cap 131 and is less likely to come into contact with other objects and be damaged. The outer surface of the end cap 131 referred to here refers to the surface on one side of the end cap 131 that is away from the case 12.

[0149] In some embodiments, as shown in FIG. 12, the end cap assembly 13 of the battery cell 1 further includes a protective membrane 136, which covers the opening of the recess 133 to protect the pressure relief mechanism 134.

[0150] According to some embodiments of the present application, the embodiments of the present application provide a battery 100, which includes the battery cell 1 described above.

[0151] According to some embodiments of the present application, the embodiments of the present application provide a battery 100, which includes the end cap 131 described above or the end cap assembly 13 described above.

[0152] According to some embodiments of the present application, embodiments of the present application provide a power consuming device, the power consuming device including the battery 100 described above.

[0153] The power consuming device may be any one of the devices or systems described above that utilizes the battery 100 .

[0154] According to some embodiments of the present application, referring to Figures 6 to 10, the present application provides an end cap 131, which is circular and has through holes 135 for attaching two electrode terminals 132 to the end cap 131, the two through holes 135 being arranged symmetrically with respect to the center of the end cap 131, and the perpendicular bisector α of the connecting line of the two through holes 135 passing through the center of the end cap 131.

[0155] The end cap 131 further includes a groove 133, which is symmetrical about the perpendicular bisector α. The side walls of the groove 133 include an arc-shaped wall 1331 and a flat wall 1332. Both ends of the arc-shaped wall 1331 and both ends of the flat wall 1332 are connected, forming an arc-shaped circumferential wall. The arc-shaped wall 1331 and the flat wall 1332 transition along an arc, resulting in rounded, chamfered corners of the side walls of the groove 133. The arc-shaped wall 1331 extends along the circumferential direction of the end cap 131. A third gap L3, which is 3.5 mm, is between the arc-shaped wall 1331 and the edge of the end cap 131. The groove 133 is formed by recessing the surface of the end cap 131 facing away from the battery cell 1 case 12 in the thickness direction, so that the thickness of the bottom wall of the groove 133 is thinner than the thickness of the end cap 131. The bottom wall of the groove 133 serves as a pressure relief mechanism 134, on which a weakened portion 1341 is provided. The weakened portion 1341 is a second groove or notch formed by punching, and the weakened portion 1341 on the bottom wall of the groove 133 is even thinner. The weakened portion 1341 is symmetrical with respect to the perpendicular bisector α, and the depth of the weakened portion 1341 is arranged in a continuously gradual manner, with the weakened portion 1341 being deepest at the intersection with the perpendicular bisector α and gradually decreasing on both sides of the perpendicular bisector α in the direction away from the perpendicular bisector α. When the internal pressure of the battery cell 1 reaches a threshold, the stress on the perpendicular bisector α of the end cap 131 is relatively concentrated. The intersection of the weak part 1341 and the perpendicular bisector α is the thinnest part of the entire pressure relief mechanism 134, but the force received there is the greatest, which has the effect of causing the pressure relief mechanism 134 to burst at a specific point. Under the action of the internal pressure of the battery cell 1, the pressure relief mechanism 134 further tears along the weak part 1341. After the tear, the pressure relief mechanism 134 remains connected to the flat wall 1332, preventing it from flying out after it is broken. Furthermore, the discharged material is limited to escaping toward the edge of the end cap 131, improving safety.

[0156] A step surface 1333 is formed on the side wall of the groove 133, and the step surface 1333 divides the side wall of the groove 133 into two parts, upper and lower, along the thickness direction β of the end cap, with the side wall of the upper part offset from the side wall of the lower part, and the opening area of ​​the groove 133 is larger than the bottom wall area of ​​the groove 133 to facilitate the escape of waste.

[0157] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Those skilled in the art can make various modifications and variations to the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application. [Explanation of symbols]

[0158] 1000—vehicle, 100—battery, 200—motor, 300—controller, 101—housing, 1011—first part, 1012—second part, 102—battery module, 1—battery cell, 11—electrode assembly, 12—case, 121—opening, 13—end cap assembly, 131—end cap, 132—electrode terminal, 1321—first wall, 133—groove, 1331—arc-shaped wall, 1332—flat wall, 1333—step surface, 134—pressure relief mechanism, 1341—weakened part, 135—through hole, 136—protective membrane, L1—first spacing distance, L2—second spacing distance, L3—third spacing distance, α—perpendicular bisector, β—thickness direction of end cap, γ—arc angle.

Claims

1. An end cap for use with a battery cell, comprising: two through holes penetrating the end cap for attaching electrode terminals; a groove formed by recessing a surface of the end cap along a thickness direction, the bottom wall of the groove forming a pressure relief mechanism; a weak part disposed on the pressure relief mechanism for relieving internal pressure of the battery cell; Here, the depth of the weakened portion gradually decreases along one or both sides of a perpendicular bisector of the connecting line of the two through holes in a direction away from the perpendicular bisector, a perpendicular bisector of the connecting line between the two through holes passes through a center of the weakened portion, The end cap is circular, the perpendicular bisector passes through a center of the end cap, and the weakened portion extends along a circumferential direction of the end cap.

2. The end cap of claim 1 , wherein the weakened portion is symmetrical about the perpendicular bisector.

3. The end cap of claim 1 , wherein the recessed groove is symmetrical about the perpendicular bisector.

4. An end cap for use with a battery cell, comprising: two through holes penetrating the end cap for attaching electrode terminals; a groove formed by recessing a surface of the end cap along a thickness direction, the bottom wall of the groove forming a pressure relief mechanism; a weak part disposed on the pressure relief mechanism for relieving internal pressure of the battery cell; Here, the depth of the weakened portion gradually decreases along one or both sides of a perpendicular bisector of the connecting line of the two through holes in a direction away from the perpendicular bisector, The groove includes an arcuate wall and a flat wall, the arcuate wall and the flat wall are mutually surrounding, and the arcuate wall extends along the circumferential direction of the end cap.

5. The end cap of claim 4 , wherein the arcuate angle enclosed by the arcuate wall is less than or equal to 180°.

6. the weakened portion and the arcuate wall have a first separation distance; and / or the ends of the weakened portion and the flat wall have a second separation distance; and / or The end cap of claim 4 , wherein the arcuate wall and the edge of the end cap have a third spacing distance.

7. The end cap of claim 4 , wherein the transition between the arcuate wall and the flat wall is an arc.

8. The end cap according to claim 1 , wherein a step surface is formed on a side wall of the groove, and the step surface extends along a circumferential direction of the groove.

9. 1. An end cap assembly comprising: End caps and a groove formed by recessing a surface of the end cap along a thickness direction, the groove having a bottom wall that forms a pressure relief mechanism, the groove including an arc-shaped wall that extends along a circumferential direction of the end cap; a weakened portion disposed to break when the pressure release mechanism is activated and disposed to correspond to the shape of the arc-shaped wall; The depth of the weakened portion gradually decreases along the direction of extension from the middle portion of the arcuate wall to both ends.

10. The end cap assembly of claim 9 , wherein the weakened portion is arcuate, and the weakened portion has a depth dimension that varies along the circumferential extension of the arcuate portion.

11. 11. The end cap assembly of claim 9 or 10, wherein the end cap assembly further includes an electrode terminal, the electrode terminal including a flat first wall, the groove further including a flat wall connecting both ends of the arc-shaped wall, and the first wall being substantially parallel to the flat wall.

12. 1. An end cap assembly comprising: End caps and a groove formed by recessing a surface of the end cap along a thickness direction, the groove having a bottom wall that forms a pressure relief mechanism, the groove including an arc-shaped wall that extends along a circumferential direction of the end cap; a weakened portion disposed to break when the pressure release mechanism is activated and disposed to correspond to the shape of the arc-shaped wall; the end cap assembly further includes an electrode terminal, the electrode terminal including a flat first wall, the groove further including a flat wall connecting both ends of the arc-shaped wall, the first wall being substantially parallel to the flat wall, and The end cap assembly further includes two through holes, which are used to attach the electrode terminals, and the depth of the weakened portion gradually decreases along one or both sides of a perpendicular bisector of a connection line of the two through holes in a direction away from the perpendicular bisector.

13. The end cap assembly of claim 12 , wherein the weakened portion is arcuate, and the weakened portion has a depth dimension that varies along the circumferential extension of the arcuate portion.

14. A battery comprising an end cap according to claim 1 or 4, or an end cap assembly according to claim 9 or 12.

15. 15. A power consuming device comprising the battery of claim 14.

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