Cover plate structure, battery cell, battery pack, and electric device

Abstract

The application provides a cover plate structure, an electric core, a battery pack and an electric device. The cover plate structure comprises a cover plate and an explosion-proof valve. The cover plate has an explosion-proof hole. The explosion-proof valve comprises an opening part and a connecting part. The opening part has a to-be-broken part at the edge of the opening part, and the to-be-broken part extends along the circumference of the opening part. The connecting part is connected to the opening part and surrounds the outer periphery of the opening part. The connecting part is connected to the cover plate to block the explosion-proof hole. In the longitudinal section of the explosion-proof valve, the length of the single-side extension track of the connecting part is L1. The straight-line distance between the first end of the connecting part close to the opening part and the second end of the connecting part away from the opening part is L2, and L2 is less than L1. The connecting part has an energy absorption groove. In this way, the reliability of the explosion-proof valve is improved, and the safety performance of the electric core is improved.

Description

Technical Field

[0001] This application relates to the field of electrical equipment technology, specifically to a cover structure, a battery cell, a battery pack, and electrical equipment. Background Technology

[0002] A battery is a device that provides power to electrical equipment. A battery cell typically includes a casing, electrode arrays, and a cover structure. The electrode arrays are located inside the casing, and the cover structure seals the casing and provides electrical connection between the electrode arrays and external electrical components. The cover structure includes a cover plate and an explosion-proof valve connected to the cover plate.

[0003] In related technologies, the structural strength of the un-disconnected part of the explosion-proof valve is low, which leads to a decrease in the stability of the opening pressure of the explosion-proof valve and affects the safety performance of the battery cell. Utility Model Content

[0004] This application provides a cover plate structure, a battery cell, a battery pack, and an electrical device to address the problem of how to avoid the low structural strength of the unopenable part of the explosion-proof valve, which leads to a decrease in the stability of the opening pressure of the explosion-proof valve and affects the safety performance of the battery cell.

[0005] To achieve the above objectives, the embodiments of this application adopt the following technical solutions: In a first aspect, embodiments of this application provide a cover plate structure, which includes a cover plate and an explosion-proof valve. The cover plate has an explosion-proof hole. The explosion-proof valve includes an opening portion and a connecting portion. The edge of the opening portion has a part to be disconnected, which extends circumferentially along the opening portion. The connecting portion connects to the opening portion and surrounds the outer periphery of the opening portion; the connecting portion is connected to the cover plate to block the explosion-proof hole; within the longitudinal section of the explosion-proof valve, the length of the single-sided extension trajectory of the connecting portion is L1; the straight-line distance between the first end of the connecting portion near the opening portion and the second end of the connecting portion away from the opening portion is L2, where L2 is less than L1. The connecting portion has an energy-absorbing groove.

[0006] In some possible implementations of the first aspect, the connecting portion includes two first connecting sections and a second connecting section extending along the thickness direction of the explosion-proof valve. The two first connecting sections are spaced apart along the arrangement direction of the opening portion and the connecting portion; wherein, one of the two first connecting sections is connected to the opening portion, and the other of the two first connecting sections is connected to the cover plate. The second connecting section is connected between the two first connecting sections; the second connecting section has an energy-absorbing groove.

[0007] In some possible implementations of the first aspect, the connecting portion includes: a first connecting section and a second connecting section. The first connecting section is connected to the opening portion and extends along the thickness direction of the explosion-proof valve. The second connecting section is connected to one end of the first connecting section and is located on the side of the first connecting section away from the opening portion; the second connecting section is connected to a cover plate; wherein the second connecting section has an energy-absorbing groove.

[0008] In some possible implementations of the first aspect, the connecting portion includes: a first connecting section and a second connecting section. The second connecting section is connected to the opening portion; the second connecting section has an energy-absorbing groove; a first end of the first connecting section is connected to the end of the second connecting section away from the opening portion; a second section of the first connecting section is connected to a cover plate; the first connecting section extends along the thickness direction of the explosion-proof valve.

[0009] In some possible implementations of the first aspect, the second connecting section has a first surface and a second surface facing away from each other along the thickness direction of the explosion-proof valve; the first surface and the second surface are respectively provided with energy-absorbing grooves.

[0010] In some possible implementations of the first aspect, the energy-absorbing grooves located on the first surface and the energy-absorbing grooves located on the second surface are spaced apart along the arrangement direction of the opening portion and the connecting portion.

[0011] In some possible implementations of the first aspect, the maximum material thickness H of the second connecting section satisfies: 0.3mm≤H≤0.6mm; the depth h of the energy absorption groove satisfies: 0.16≤h / H≤0.65.

[0012] In some possible implementations of the first aspect, the width W of the energy-absorbing groove satisfies: 0.25mm≤W≤1.2mm.

[0013] Secondly, embodiments of this application also provide a battery cell, comprising: a housing and a cover structure according to any of the foregoing implementations. The housing has an opening. The cover structure is connected to the housing and seals the opening.

[0014] Thirdly, embodiments of this application also provide a battery pack, which includes a casing and battery cells according to any of the aforementioned implementations. The battery cells are installed in the casing.

[0015] Fourthly, embodiments of this application also provide an electrical device, which includes an electrical user body and a battery pack according to any of the aforementioned implementations. The battery pack is electrically connected to the electrical user body.

[0016] The cover structure, battery cell, battery pack, and electrical equipment provided in this application have the following beneficial effects: When the explosion-proof valve is connected to the cover plate (e.g., through welding), certain stress is generated, and this stress inevitably gets released to the disconnecting section of the explosion-proof valve. This disconnecting section is the easiest point on the explosion-proof valve to disconnect in the event of thermal runaway of the battery cell. Its structural strength is relatively low compared to other parts of the explosion-proof valve. Therefore, when stress is released to this section, its structural strength decreases, leading to a reduction in the stability of the explosion-proof valve's opening pressure and affecting the safety performance of the battery cell.

[0017] Therefore, the length L1 of the single-sided extension trajectory of the connecting part within the longitudinal section of the explosion-proof valve is set to be less than the straight-line distance L2 between the first end of the connecting part near the opening part and the second end of the connecting part away from the opening part. This results in the connecting part extending non-linearly within the longitudinal section of the explosion-proof valve. In this way, when the explosion-proof valve is connected to the cover plate and stress is generated towards the disconnected part, on the one hand, the connecting part can deform to a certain extent based on its own shape to absorb the stress. Furthermore, the energy-absorbing groove on the connecting part provides a certain deformation space for the connecting part, making it easier for the connecting part to deform under stress and absorb the stress, preventing the stress from being transmitted to the disconnected part. On the other hand, the shape of the connecting part increases the path size required for the stress to be released to the disconnected part of the explosion-proof valve, making the stress reaching the disconnected part very small or almost non-existent. This is beneficial to improving the structural strength of the disconnected part, thereby improving the reliability of the explosion-proof valve and the safety performance of the battery cell. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of an electrical device provided for some embodiments of this application.

[0019] Figure 2 for Figure 1 The diagram shows a cross-sectional view of the battery pack of the electrical device.

[0020] Figure 3 for Figure 2 The diagram shows the structural structure of the battery cells in the battery pack.

[0021] Figure 4 for Figure 3 An exploded view of the cover plate structure shown (also showing the pole).

[0022] Figure 5 for Figure 4 A top view of the cover plate structure shown (also showing the pole).

[0023] Figure 6 for Figure 5 The cover plate structure shown is a cross-sectional view at line AA.

[0024] Figure 7 for Figure 6 A magnified view of the area within box B.

[0025] Figure 8 for Figure 4 The diagram shows the structure of the explosion-proof valve.

[0026] Figure 9 for Figure 8 The diagram shows the structure of the explosion-proof valve from another perspective.

[0027] Explanation of reference numerals in the attached figures: Electrical equipment 1000; battery pack 100; main electrical unit 200; outer casing 20; battery compartment 1001; Cell 10; Cover structure 1; Cover 11; Explosion-proof hole 11a; Housing 2; Terminal post 3; Cover plate 13; Explosion-proof valve 12; opening part 121; disconnection part 1211; second connecting section 122; energy absorption groove 1221; first connecting section 1222; second connecting section 1223; first surface 1223a; second surface 1223b. Detailed Implementation

[0028] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0029] In this application, the accompanying drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features.

[0030] Unless otherwise stated, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. The term "and / or" as used in this application includes any and all combinations of one or more of the associated listed items. The singular forms "a," "the," and "the" as used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0031] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified. In the description of this application, "several" means one or more, unless otherwise explicitly specified.

[0032] In the description of this application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the purpose of simplifying the description of this application and do not indicate that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. In other words, they should not be construed as limitations on this application.

[0033] In the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "linking," "fixing," "setting," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can also refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0034] In the description of this application, unless otherwise expressly defined, the terms "above," "over," "on top of," "below," "below," "under," or "below" for "first feature over second feature" can refer to the first and second features being in direct contact, or to the first and second features being in indirect contact through an intermediate medium. Furthermore, "above," "below," and "over" for "first feature over second feature" can mean the first feature is directly above or diagonally above the second feature, or simply indicates that the horizontal height of the first feature is higher than the horizontal height of the second feature. Similarly, "below," "below," and "below" for "first feature over second feature" can mean the first feature is directly below or diagonally below the second feature, or simply indicates that the horizontal height of the first feature is lower than the horizontal height of the second feature.

[0035] A battery is a device that provides power to electrical equipment. A battery cell typically includes a casing, electrode arrays, and a cover structure. The electrode arrays are located inside the casing, and the cover structure seals the casing and provides electrical connection between the electrode arrays and external electrical components. The cover structure includes a cover plate and an explosion-proof valve connected to the cover plate.

[0036] It is understandable that when the explosion-proof valve and the cover plate are connected by means such as welding, certain stress will be generated at the connection point. This stress will inevitably be released to the disconnectable part of the explosion-proof valve. The disconnectable part is the most likely point on the explosion-proof valve to disconnect in the event of thermal runaway of the battery cell. Its structural strength is relatively low compared to other parts of the explosion-proof valve. Therefore, when stress is released to the disconnectable part, it will reduce the structural strength of the disconnectable part, thereby reducing the stability of the opening pressure of the explosion-proof valve and affecting the safety performance of the battery cell.

[0037] To address the aforementioned issues, this application provides a cover plate structure, a battery cell, a battery pack, and an electrical device. By setting the length L1 of the single-sided extension trajectory of the connecting part within the longitudinal section of the explosion-proof valve to be less than the straight-line distance L2 between the first end of the connecting part near the opening portion and the second end of the connecting part away from the opening portion, the connecting part extends non-linearly within the longitudinal section of the explosion-proof valve. Thus, when the explosion-proof valve is connected to the cover plate and stress is generated towards the disconnected portion, on the one hand, the connecting part can deform to a certain extent based on its shape to absorb the stress. Furthermore, the connecting part is provided with an energy-absorbing groove, which provides a certain deformation space for the connecting part, making it easier for the connecting part to deform under stress and absorb the stress, preventing the stress from being transmitted to the disconnected portion. On the other hand, the shape of the connecting part increases the path size required for stress release to the disconnected portion of the explosion-proof valve, making the stress reaching the disconnected portion very small or almost non-existent. This helps improve the structural strength of the disconnected portion, thereby improving the reliability of the explosion-proof valve and the safety performance of the battery cell.

[0038] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0039] Please see Figure 1 , Figure 1 This is a schematic diagram of an electrical device 1000 provided in some embodiments of this application. Figure 1 In the illustrated embodiment, an electric vehicle is used as an example of the electrical device 1000 for illustrative purposes, which should not be construed as a specific limitation of this application. In other embodiments, the electrical device may also be a mobile phone, a laptop computer, a mobile charging station, or other similar devices.

[0040] Please continue reading. Figure 1 The electrical device 1000 includes a power-consuming body 200 and a battery pack 100. The battery pack 100 is fixed to the power-consuming body 200 and electrically connected to the power-consuming components of the power-consuming body 200 to supply power to the power-consuming components of the power-consuming body 200. Specifically, the power-consuming body 200 may have a battery compartment 1001, and the battery pack 100 is fixed inside the battery compartment 1001.

[0041] Please see Figure 2 , Figure 2 for Figure 1 A cross-sectional structural diagram of the battery pack 100 of the electrical device 1000 shown.

[0042] The battery pack 100 may include a housing 20 and at least one battery cell 10. The battery cell 10 is electrically connected to the aforementioned power-consuming body 200. The battery cell 10 is fixed inside the housing 20, which protects the battery cell 10 from external forces causing vibration and impact that could damage it. The housing 20 may be a metal housing or a plastic housing.

[0043] Cell 10 is the most basic electrochemical unit, capable of storing and releasing electrical energy. Cell 10 can be a lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc., and this application embodiment does not limit it to this.

[0044] Figure 2 In the battery pack 100 shown, there are multiple battery cells 10. These multiple battery cells 10 can be electrically connected in series, in parallel, or in a mixed configuration. A mixed configuration means that the multiple battery cells 10 are connected in both series and parallel relationships, which can be specifically designed according to the power requirements of the electrical device 1000. In some other embodiments, the battery pack 100 may contain only one battery cell 10.

[0045] Please refer to the following: Figure 3 and Figure 4 , Figure 3 for Figure 2 A schematic diagram of the structure of the battery cell 10 in the battery pack 100 shown; Figure 4 for Figure 3 An exploded view of the cover structure shown (also showing the poles); the cell 10 includes a housing 2, a pole group (not shown in the figure), a cover structure 1, and poles 3.

[0046] The housing 2 has a receiving cavity (not shown in the figure) and an opening communicating with the receiving cavity. The receiving cavity is used to receive the electrode assembly and electrolyte, and the opening is used to place the electrode assembly inside the receiving cavity.

[0047] Figure 3 In the illustrated embodiment, the housing 2 can be a rigid component, and the housing 2 can be generally rectangular in shape so that the battery cell 10 is generally rectangular in shape. The housing 2 can be a metal housing.

[0048] In some examples, the housing 2 can be an aluminum alloy housing to make it lighter, which is beneficial for the weight reduction of the battery cell 10, and thus for the overall weight reduction of the electrical equipment 1000. In other examples, the housing 2 can also be a stainless steel housing to make it stronger, which in turn gives the battery cell 10 better overall strength and stronger resistance to puncture and vibration damage. In still other embodiments, the housing 2 can also be a flexible component.

[0049] The electrode assembly is disposed within a receiving cavity and immersed in an electrolyte. The electrode assembly includes a positive electrode (not shown), a negative electrode (not shown), and a separator (not shown). The positive electrode can be formed from a positive current collector and a positive active material coated on the current collector. In some examples, the positive current collector can be aluminum foil, and the positive active material can be lithium cobalt oxide (LCO), ternary materials (NCM / NCA), lithium iron phosphate (LFP), etc. Based on this, the electrode assembly also includes a positive electrode tab (not shown), which is connected to the positive electrode and electrically conductive. Specifically, the positive electrode tab can be fixed to the positive current collector by welding or integrally formed with the positive current collector.

[0050] The negative electrode sheet can be formed from a negative current collector and a negative active material coated on the negative current collector. In some examples, the negative current collector can be copper foil, and the negative active material can be graphite, silicon-carbon composite material, etc. Based on this, the electrode assembly also includes a negative electrode tab (not shown in the figure), which is connected to the negative electrode sheet and is electrically conductive. The negative electrode tab and the positive electrode tab are used to electrically connect the electrode assembly to the circuit. Specifically, the negative electrode tab can be fixed to the negative current collector by welding, or it can be integrally formed with the negative current collector.

[0051] A separator is placed between the positive and negative electrode plates to isolate them and prevent short circuits. The separator can be made of porous polyethylene (PE) or polypropylene (PP), etc.

[0052] Please refer to the following: Figure 5 and Figure 6 , Figure 5 for Figure 4 Top view of the cover plate structure shown (also showing the poles); Figure 6 for Figure 5 The diagram shows a cross-sectional view of cell 10 at the AA line. Please refer to [link / reference]. Figures 3 to 6 The cover structure 1 includes a cover plate 11, an explosion-proof valve 12, and a cover plate 13.

[0053] The cover plate 11 is connected to the housing 2 and seals the opening to protect the electrode assembly and prevent electrolyte leakage. Figure 3 and Figure 4 In the illustrated embodiment, the cover plate 11 is generally rectangular flat. In other embodiments, the cover plate 11 may also be circular, triangular, or other shapes.

[0054] The electrode post 3 is disposed on the cover plate 11. Specifically, the cover plate 11 may have an electrode post hole (not shown in the figure). The electrode post 3 may pass through the electrode post hole and be fixed to the cover plate 11. Figure 3In the embodiment shown, there are two poles 3, which are arranged along the length of the cover plate 11. The aforementioned positive electrode tab is electrically connected to one pole 3, and the aforementioned negative electrode tab is electrically connected to the other pole 3.

[0055] The cover plate 11 can be a metal structural component, connected to the housing 2 by welding, bonding, or snap-fitting. In some examples, the cover plate 11 can be an aluminum alloy structural component, which is beneficial for the weight reduction of the battery cell 10 and the electrical equipment 1000. In other examples, the cover plate 11 can be a stainless steel component, so that the cover plate 11 has high strength, and thus the battery cell 10 has high strength.

[0056] The cover plate 11 has an explosion-proof hole 11a extending through the cover plate 11 along its thickness direction. The explosion-proof valve 12 is adapted to the shape of the explosion-proof hole 11a, and is connected to the cover plate 11, thus blocking the explosion-proof hole 11a.

[0057] In some embodiments, the inner wall of the explosion-proof hole 11a may be stepped. The dimension of the end of the explosion-proof hole 11a facing the inside of the housing 2 is larger than the dimension of the end of the explosion-proof hole 11a facing the outside of the housing 2. The explosion-proof valve 12 is disposed at the stepped surface of the explosion-proof hole 11a of the cover plate 11 and seals the explosion-proof hole 11a.

[0058] The explosion-proof valve 12 can be a metal structural component. For example, the explosion-proof valve 12 can be an aluminum alloy structural component (such as a manganese-aluminum alloy component), which is beneficial for the weight reduction of the battery cell 10 and the electrical equipment 1000. Alternatively, the explosion-proof valve 12 can also be a stainless steel structural component, so that the explosion-proof valve 12 has higher strength, which in turn makes the battery cell 10 have higher strength.

[0059] In some embodiments, the cover plate 13 is connected to the cover plate 11 and located on the side of the explosion-proof valve 12 away from the center of the housing 2, to cover at least a portion of the explosion-proof valve 12. This prevents external moisture, dust, and other impurities from entering the battery cell 10 through the explosion-proof hole 11a and the explosion-proof valve 12, thus affecting the stability of the battery cell 10's operation. For example, the cover plate 13 is connected to the cover plate 11 by adhesive backing. The cover plate 13 can be a plastic part (such as PET, PC, or PE), thereby reducing the weight of the battery cell 10. In addition, plastic parts have good insulation properties. Therefore, when the battery cell 10 experiences thermal runaway and the thermal runaway gas pushes open the cover plate 13, the plastic cover plate 13, with its own insulation properties, can prevent short circuits from occurring inside the battery cell 10 or between the battery cell and other battery cells, thereby improving the safety performance of the battery cell 10.

[0060] It is understandable that there is a gap between the cover plate 11 and the cover plate 13, so that the cover plate 13 can both satisfy the function of dust prevention and avoid affecting the opening pressure of the explosion-proof valve 12 and the stability of the opening of the explosion-proof valve 12.

[0061] Please refer to the following: Figures 7-9 , Figure 7 for Figure 6 A magnified view of a portion of box B in the image; Figure 8 for Figure 4 The diagram shows the structure of the explosion-proof valve 12. Figure 9 for Figure 8 The diagram shows the structure of the explosion-proof valve 12 from another perspective. The explosion-proof valve 12 includes an opening part 121 and a connecting part 122.

[0062] The opening portion 121 has a section to be broken 1211 at its edge, and the section to be broken 1211 extends circumferentially along the opening portion. For example, a reference line is defined by the midpoint of the line connecting the center of the opening portion 121 and all points on the outer edge of the opening portion 121. The portion of the opening portion 121 located on the reference line away from the center of the opening portion 121 is the edge of the opening portion 121. In some embodiments, the section to be broken 1211 is a groove.

[0063] The connecting part 122 is connected to the opening part 121 and surrounds the outer periphery of the opening part 121. The connecting part 122 is connected to the cover plate 11 so that the explosion-proof valve 12 blocks the explosion-proof hole 11a.

[0064] Within the longitudinal section of the explosion-proof valve 12, the length of the single-sided extension trajectory of the connecting portion 122 is L1; the straight-line distance between the first end of the connecting portion 122 near the opening portion 121 and the second end of the connecting portion 122 away from the opening portion 121 is L2, where L2 is less than L1. It should be noted that... Figure 7 The connecting portion 122 shown is composed of three connecting segments. Therefore, the length L1 of the unilateral extension trajectory of the connecting portion 122 can be expressed as the sum of the lengths L11, L12, and L13 of the three connecting segments. However, Figure 7 The structure of the connecting part 122 shown is merely an example and should not be construed as limiting the scope of this application.

[0065] It is understandable that stress will be generated at the connection point when the connecting part 122 is connected to the cover plate 11, and this stress often needs to be released. Since the disconnectable part 1211 of the explosion-proof valve 12 is relatively close to the connection point between the explosion-proof valve 12 and the cover plate 11 (for example, when the connecting part 122 is welded to the cover plate 11, this connection point is a weld point), stress will inevitably be released to the disconnectable part 1211 of the explosion-proof valve. The disconnectable part 1211 is the most likely point on the explosion-proof valve 12 to disconnect in the event of thermal runaway of the battery cell 10. The structural strength of the disconnectable part 1211 itself is relatively low compared to other parts of the explosion-proof valve 12. Combined with the effect of stress on the disconnectable part 1211, the structural strength of the disconnectable part 1211 decreases, which in turn reduces the stability of the opening pressure of the explosion-proof valve 12, affecting the safety performance of the battery cell 10.

[0066] Therefore, in this embodiment, by setting the length L1 of the single-sided extension trajectory of the connecting part 122 in the longitudinal section of the explosion-proof valve 12 to be less than the straight-line distance L2 between the first end of the connecting part 122 near the opening part 121 and the second end of the connecting part 122 away from the opening part 121, the connecting part extends non-linearly in the longitudinal section of the explosion-proof valve 12. In this way, when the explosion-proof valve 12 is connected to the cover plate 11 and stress is generated toward the disconnected part 1211, on the one hand, the connecting part 122 can deform to a certain extent based on its own shape to absorb the stress. On the other hand, the shape of the connecting part 122 increases the path size required for the stress to be released to the disconnected part 1211 of the explosion-proof valve 12, so that the stress reaching the disconnected part 1211 is very small or almost non-existent. This can prevent the stress from being transmitted to the disconnected part 1211 and affecting the structural strength of the disconnected part 1211, thereby improving the reliability of the explosion-proof valve 12 and the safety performance of the battery cell 10.

[0067] It is understandable that when the connecting part 122 is welded to the cover plate 11, a certain amount of welding heat will be generated. This welding heat will be conducted in the explosion-proof valve 12, causing different temperatures in different parts of the explosion-proof valve 12. For example, the temperature of the disconnected part 1211 is different from that of other parts of the explosion-proof valve 12. In this case, based on the thermal expansion and contraction effect, the disconnected part 1211 will undergo a certain amount of deformation relative to other parts of the explosion-proof valve 12. Since the material thickness at the disconnected part 1211 is relatively thin, even a small deformation may lead to a reduction in the structural strength of the disconnected part 1211.

[0068] In this case, if the length L1 of the single-sided extension trajectory of the connecting part 122 within the longitudinal section of the explosion-proof valve 12 is equal to the straight-line distance L2 between the two ends of the connecting part 122, the welding heat will be conducted along the connecting part 122 to the part to be disconnected 1211 via the shortest path (i.e., straight-line transmission), affecting the structural strength of the groove and causing instability in the opening pressure of the groove, thereby reducing the reliability of the explosion-proof valve 12. Therefore, the length L1 of the single-sided extension trajectory of the connecting part 122 within the longitudinal section of the explosion-proof valve 12 is set to be less than the straight-line distance L2 between the two ends of the connecting part 122 (hereinafter referred to as L1 < L2). In this way, the path of welding heat from the weld point (i.e., the point where the connecting part 122 is welded to the cover plate 11) to the part to be disconnected 1211 can be extended, thereby reducing the impact of welding heat on the structural strength of the part to be disconnected 1211, which is beneficial to improving the reliability of the explosion-proof valve 12 and improving the safety performance of the battery cell.

[0069] It should be noted that the longitudinal section mentioned in this application refers to the cross section formed by cutting the object along a plane passing through the object's axis. Since the connecting part 122 surrounds the outer periphery of the opening part 121, that is, the connecting part 122 is annular, the longitudinal section of the connecting part 122 includes a first part and a second part spaced apart, and the single-sided extension trajectory of the connecting part 122 is either the extension trajectory of the first part or the extension trajectory of the second part.

[0070] It should be noted that the preceding description uses the example of the connection between the connecting part 122 and the cover plate 11 being welded, and does not mean that the connecting part 122 and the cover plate 11 can only be connected by welding. In other embodiments, the connecting part 122 and the cover plate 11 can also be connected by bonding, interference fit, etc., and this application does not limit this.

[0071] In some embodiments, see Figure 7 and Figure 8 The connecting portion 122 has an energy-absorbing groove 1221. For example, the connecting portion 122 has an energy-absorbing groove 1221 on at least one side surface along the thickness direction of the explosion-proof valve 12.

[0072] Understandably, the energy-absorbing groove 1221 provides a certain amount of space for deformation of the connecting part 122, making it easier for the connecting part 122 to deform under stress and absorb stress. This prevents the stress from being transmitted to the part to be disconnected 1211, thus affecting the structural strength of the part to be disconnected 1211. This, in turn, helps improve the reliability of the explosion-proof valve 12 and the safety performance of the battery cell 10. Since the thermal conductivity of air is lower than that of metal structural components, when both the explosion-proof valve 12 and the cover plate 11 are metal structural components, and the connecting part 122 is welded to the cover plate 11, the energy-absorbing groove 1221 in the connecting part 122 can provide a certain degree of barrier to the welding heat. This reduces the impact of the welding heat on the structural strength of the part to be disconnected 1211, thereby improving the stability of the opening pressure of the explosion-proof valve 12 and enhancing its reliability.

[0073] In some embodiments, see Figures 7-9 The connecting portion 122 includes a first connecting segment 1222 and a second connecting segment 1223. The second connecting segment 1223 extends along the arrangement direction of the opening portion 121 and the connecting portion 122. The first connecting segment 1222 is connected to the second connecting segment 1223, and the first connecting segment 1222 extends along the thickness direction of the explosion-proof valve 12. At this time, the length L1 of the single-sided extension trajectory of the connecting portion 122 in the longitudinal section of the explosion-proof valve 12 includes the length L11 of the first connecting segment 1222 and the length L12 of the second connecting segment 1223.

[0074] In this way, L1 < L2, extending the length between the connection point of the connecting part 122 and the cover plate 11 and the part to be separated 1211, thus extending the stress transmission path and reducing the stress transmission to the part to be separated 1211. Furthermore, since the first connecting segment 1222 and the second connecting segment 1223 extend in different directions, there is an inflection point at the connection point. Therefore, the connecting part 122 is more likely to deform at this inflection point to absorb stress, thereby improving the structural strength of the part to be separated 1211. Moreover, when the connecting part 122 is welded to the cover plate 11, the heat transfer path of the welding process is also extended, thereby reducing the impact of the welding heat on the structural strength of the part to be separated 1211.

[0075] For example, the second connecting segment 1223 is connected to one end of the first connecting segment 1222, and the second connecting segment 1223 is located on the side of the first connecting segment 1222 away from the opening portion 121. The second connecting segment 1223 is connected to the cover plate 11 (e.g., by welding).

[0076] For example, the first end of the first connecting segment 1222 is connected to the end of the second connecting segment 1223 away from the opening portion 121, and the second segment of the first connecting segment 1222 is connected to the cover plate 11 (e.g., by welding).

[0077] For example, there are two first connecting segments 1222. The two first connecting segments 1222 extend along the thickness direction of the explosion-proof valve 12, and are spaced apart along the arrangement direction of the opening portion 121 and the connecting portion 122. Furthermore, one of the two first connecting segments 1222 is connected to the opening portion 121, and the other is connected to the cover plate 11 (e.g., by welding). A second connecting segment 1223 is connected between the two first connecting segments 1222. In this case, the length L1 of the unilateral extension trajectory of the connecting portion 122 within the longitudinal section of the explosion-proof valve 12 includes the lengths of the two first connecting segments 1222 (i.e., the sum of L11 and L13) and the length L12 of the second connecting segment 1223. This further extends the stress transmission path and the transmission path of the welding heat generated when the connecting portion 122 is welded to the cover plate 11, thereby reducing the impact of welding heat on the structural strength of the unsevered portion 1211.

[0078] It is understood that the structure of the connection 122 is not limited to the examples mentioned above. In some other examples, the connection 122 may be wavy or other irregular in shape. As long as the connection 122 is easy to deform under stress, and plays the role of absorbing heat and extending the heat transfer path of welding, any implementation of the connection 122 should be within the scope of protection of this application.

[0079] In some embodiments, see Figure 7 and Figure 8 The second connecting section 1223 has an energy-absorbing groove 1221. It can be understood that the second connecting section 1223 extends along the arrangement direction of the opening part 121 and the connecting part 122. Compared with the first connecting section 1222, the second connecting section 1223 is straighter. Therefore, the straight surface of the second connecting section 1223 is more convenient to form the energy-absorbing groove 1221 by cutting or die casting, thereby reducing the production cost of the explosion-proof valve 12 and improving the production efficiency of the explosion-proof valve 12.

[0080] In some embodiments, see Figure 7 and Figure 8 The second connecting section 1223 has a first surface 1223a and a second surface 1223b that are opposite to each other along the thickness direction of the explosion-proof valve 12. Energy-absorbing grooves 1221 are respectively arranged on the first surface 1223a and the second surface 1223b, that is, there are multiple energy-absorbing grooves 1221.

[0081] Thus, by forming energy-absorbing grooves 1221 on the two opposite surfaces of the second connecting section 1223, the total depth of the energy-absorbing grooves 1221 in the thickness direction of the explosion-proof valve 12 can be increased, which can further reduce the stress and the impact of the welding heat generated when the connecting part 122 is welded to the cover plate 11 on the structural strength of the disconnected part 1211, thereby improving the stability of the opening pressure of the explosion-proof valve 12 and improving the reliability of the explosion-proof valve 12.

[0082] In some embodiments, see Figure 7 and Figure 8 The energy-absorbing groove 1221 located on the first surface 1223a and the energy-absorbing groove 1221 located on the second surface 1223b are spaced apart along the arrangement direction of the opening portion 121 and the connecting portion 122.

[0083] This prevents the energy-absorbing groove 1221 on the first surface 1223a and the energy-absorbing groove 1221 on the second surface 1223b from overlapping along the thickness direction of the connecting portion 122. This would prevent the material thickness of the connecting portion 122 between the energy-absorbing groove 1221 on the first surface 1223a and the energy-absorbing groove 1221 on the second surface 1223b from being too thin, which would reduce the strength of the connecting portion 122. This would help improve the structural strength of the explosion-proof valve 12 and increase its reliability.

[0084] In some embodiments, see Figure 7The maximum material thickness H of the second connecting section 1223 satisfies: 0.3mm ≤ H ≤ 0.6mm; for example, the maximum material thickness H of the second connecting section 1223 is 0.3mm, 0.4mm, 0.5mm, or 0.6mm. The depth h of the energy-absorbing groove 1221 satisfies: 0.16 ≤ h / H ≤ 0.65. For example, the ratio of the depth h of the energy-absorbing groove 1221 to the maximum material thickness H of the second connecting section 1223 is 0.16, 0.24, 0.36, 0.48, or 0.65.

[0085] It is understandable that if the ratio of the depth h of the energy-absorbing groove 1221 to the maximum material thickness H of the second connecting section 1223 is less than 0.16, the depth h of the energy-absorbing groove 1221 is too small relative to the maximum material thickness H of the second connecting section 1223. This would reduce the heat insulation effect of the energy-absorbing groove 1221 and reduce the deformation capacity at the energy-absorbing groove 1221, thereby reducing the buffering effect of the connecting part 122 against the force. If the ratio of the depth h of the energy-absorbing groove 1221 to the maximum material thickness H of the second connecting section 1223 is greater than 0.65, the ratio of the depth h of the energy-absorbing groove 1221 to the maximum material thickness H of the second connecting section 1223 is too large, that is, the material thickness at the energy-absorbing groove 1221 is too small (e.g., it may be less than the material thickness at the part to be disconnected 1211). In this case, the explosion-proof valve 12 may disconnect at the energy-absorbing groove 1221 instead of at the part to be disconnected 1211 when the battery cell 10 thermally runs away, which will reduce the stability of the opening pressure of the explosion-proof valve and affect the safety performance of the battery cell.

[0086] Therefore, when the ratio of the depth h of the energy-absorbing groove 1221 to the maximum material thickness H of the second connecting section 1223 satisfies: 0.16≤h / H≤0.65, it is beneficial to improve the blocking effect of the energy-absorbing groove 1221 on welding heat and the buffering effect on welding stress. In addition, when the battery cell 10 thermally runs away, the explosion-proof valve 12 can be disconnected at the energy-absorbing groove 1221, thereby improving the safety performance of the battery cell 10.

[0087] In some embodiments, see Figure 7 The width W of the energy-absorbing groove 1221 satisfies the following condition: 0.25mm ≤ W ≤ 1.2mm. For example, the width W of the energy-absorbing groove 1221 is 0.25mm, 0.45mm, 0.85mm or 1.2mm.

[0088] Understandably, if W < 0.25 mm, the groove width W of the energy-absorbing groove 1221 is too small, which will reduce the heat insulation effect of the energy-absorbing groove 1221 and reduce the deformation capacity at the energy-absorbing groove 1221, thereby reducing the buffering effect of the connection part 122 on welding stress. If W > 1.2 mm, it may affect the structural strength of the second connection section 1223.

[0089] Therefore, when the groove width W of the energy-absorbing groove 1221 satisfies: 0.25mm≤W≤1.2mm, it is beneficial to improve the heat insulation effect of the second connecting section 1223, improve the buffering effect of the second connecting section 1223 on welding stress, and help ensure the structural strength of the second connecting section 1223.

[0090] It is understood that in the various embodiments of this application, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0091] It is understood that the various implementation methods described in this application can be implemented individually or in combination, and the embodiments of this application are not limited in this respect.

[0092] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the aforementioned method implementations, and will not be repeated here.

[0093] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A cover plate structure, characterized in that, include: Cover plate, the cover plate having explosion-proof holes; as well as Explosion-proof valve, the explosion-proof valve comprising: An opening portion, wherein the edge of the opening portion has a portion to be broken, the portion to be broken extending circumferentially along the opening portion; and A connecting portion is provided, which connects to the opening portion and surrounds the outer periphery of the opening portion; the connecting portion is connected to the cover plate so that the explosion-proof valve seals the explosion-proof hole; within the longitudinal section of the explosion-proof valve, the length of the single-sided extension trajectory of the connecting portion is L1; the straight-line distance between the first end of the connecting portion near the opening portion and the second end of the connecting portion away from the opening portion is L2, where L2 is less than L1; The connecting part has an energy-absorbing groove.

2. The cover plate structure according to claim 1, characterized in that, The connecting part includes: Two first connecting segments extending along the thickness direction of the explosion-proof valve are spaced apart along the arrangement direction of the opening portion and the connecting portion; wherein, one of the two first connecting segments is connected to the opening portion, and the other of the two first connecting segments is connected to the cover plate; and A second connecting segment is connected between the two first connecting segments; the second connecting segment has the energy-absorbing groove.

3. The cover plate structure according to claim 1, characterized in that, The connecting part includes: A first connecting section, which is connected to the opening portion and extends along the thickness direction of the explosion-proof valve; and The second connecting segment is connected to one end of the first connecting segment, and the second connecting segment is located on the side of the first connecting segment away from the opening portion; the second connecting segment is connected to the cover plate; wherein the second connecting segment has the energy-absorbing groove.

4. The cover plate structure according to claim 1, characterized in that, The connecting part includes: A second connecting section is connected to the opening portion; the second connecting section has the energy-absorbing groove; and A first connecting segment, the first end of which is connected to the end of the second connecting segment away from the opening portion, and the second segment of which is connected to the cover plate; the first connecting segment extends along the thickness direction of the explosion-proof valve.

5. The cover plate structure according to any one of claims 2-4, characterized in that, The second connecting section has a first surface and a second surface that are opposite to each other along the thickness direction of the explosion-proof valve; The first surface and the second surface are respectively provided with the energy-absorbing grooves.

6. The cover plate structure according to claim 5, characterized in that, The energy-absorbing groove located on the first surface and the energy-absorbing groove located on the second surface are spaced apart along the arrangement direction of the opening portion and the connecting portion.

7. The cover plate structure according to any one of claims 2-4, characterized in that, The maximum material thickness H of the second connecting section satisfies: 0.3mm ≤ H ≤ 0.6mm; the depth h of the energy-absorbing groove satisfies: 0.16 ≤ h / H ≤ 0.65; and / or The width W of the energy-absorbing groove satisfies: 0.25mm≤W≤1.2mm.

8. A battery cell, characterized in that, include: A housing having an opening; A cover plate structure, wherein the cover plate structure is the cover plate structure according to claim 7, the cover plate structure is connected to the housing and seals the opening.

9. A battery pack, characterized in that, include: shell; and The battery cell is the battery cell according to claim 8, and the battery cell is installed inside the housing.

10. An electrical appliance, characterized in that, include: Electricity-consuming entities; as well as The battery pack is the battery pack according to claim 9, and the battery pack is electrically connected to the power-consuming body.

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