Cover plate assembly and battery cell

Abstract

The application provides a cover plate assembly and a battery cell, and relates to the technical field of batteries. The cover plate assembly comprises an explosion-proof valve, a cover plate body and a support frame. The cover plate body comprises a mounting main body provided with a mounting opening and a plurality of mounting pieces. The explosion-proof valve is arranged in the mounting opening. The mounting pieces protrude from the mounting main body. The plurality of mounting pieces are divided into two groups. The two groups of mounting pieces are located on the two sides of the explosion-proof valve. The support frame comprises a plurality of support plates and two connecting pieces. The two ends of the support plates are connected with the two connecting pieces. The plurality of support plates are arranged at intervals. The two support plates surround an exhaust passage. The two connecting pieces are connected with the two groups of mounting pieces. The area of the projection of the outer contour of the support frame is S1. The area of the plurality of exhaust passages is S2. The thickness of the support plate is H. S1, S2 and H satisfy the following conditions: S1 / S2>1.5 and H / S2>0.5. The support frame can support the pole group, so that the pole group does not shield the explosion-proof valve, the exhaust effect of the explosion-proof valve is ensured, and the safety performance of the battery cell is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a cover plate assembly and a battery cell. Background Technology

[0002] Lithium-ion batteries are widely used in various fields such as transportation power supply, power storage, new energy storage power supply, aerospace and military industries due to their advantages such as large capacity, high operating voltage, strong charge retention capability, and long cycle life. A typical energy storage cell includes a cover plate, casing, bare cell, insulating film, side plates, electrode assembly, and electrolyte.

[0003] Energy storage cells generally have a large capacity and higher safety requirements. Their positive and negative terminals can be set on the same cover plate, and the explosion-proof valve is set on the opposite cover plate to achieve thermal and electrical separation and improve the safety performance of the cell.

[0004] However, when thermal runaway occurs in the battery cell, the explosion-proof valve opens to release pressure and exhaust gas. As the pressure decreases, the electrode assembly will move towards the explosion-proof valve under the impact of the high-temperature and high-pressure airflow inside the battery cell. This causes the front end of the electrode assembly to block the explosion-proof valve, which will significantly reduce the exhaust effect of the explosion-proof valve and thus weaken the safety performance of the battery cell. Summary of the Invention

[0005] In view of this, this application provides a cover plate assembly and a battery cell to solve, to some extent, the problem that electrode movement during battery cell thermal runaway can block the explosion-proof valve.

[0006] According to one aspect of this application, a cover plate assembly is provided, the cover plate assembly including an explosion-proof valve, a cover plate body and a support frame, the cover plate body including a mounting body and a plurality of mounting components, the mounting body having an mounting opening extending through the mounting body in a first direction, the explosion-proof valve being disposed in the mounting opening, the mounting components protruding from the mounting body, the plurality of mounting components being divided into two groups, the two groups of mounting components being located on both sides of the explosion-proof valve respectively; The support frame includes multiple support plates and two connectors. The two ends of each support plate are connected to the two connectors respectively. The multiple support plates are arranged at intervals. Two adjacent support plates form an exhaust channel. The two connectors are connected to two sets of mounting components respectively. Define the plane perpendicular to the first direction as the projection plane, and the area of ​​the outer contour of the projection of the support frame along the first direction onto the projection plane is... The sum of the areas of the plurality of exhaust channels is The thickness of the support plate in the first direction is , , and satisfy: .

[0007] Preferably, the cover plate assembly faces the electrode assembly, and the area of ​​the outer contour of the electrode assembly projected onto the projection plane along the first direction is... The support plate includes a support plane facing away from the cover plate body in the first direction, and the distance between the support plane and the mounting body in the first direction is... , , and satisfy: .

[0008] Preferably, the plurality of support plates are arranged at intervals along the second direction, the connector includes a connecting part and a fixing part connected to each other, the fixing part protrudes toward the mounting body relative to the connecting part, the two ends of the support plate in the third direction are respectively connected to two connecting parts of the two connectors, the two fixing parts of the two connectors are respectively connected to two sets of mounting parts, the first direction is perpendicular to the second direction, and the third direction is perpendicular to the plane determined by the first direction and the second direction.

[0009] Preferably, the mounting member includes a first boss and a second boss, the first boss protruding from the mounting body, the second boss protruding from the first boss, the surface of the fixing part facing the mounting body in the first direction abutting against the mounting body on the side of the first boss facing away from the mounting body in the first direction, the side of the fixing part facing away from the connecting part in the third direction abutting against the connecting part in the third direction, and the surface of the second boss facing away from the mounting body in the first direction being flush with the surface of the fixing part facing away from the mounting body in the first direction.

[0010] Preferably, the distance between the mounting component and the explosion-proof valve in the third direction is... , satisfy: .

[0011] Preferably, the dimension of the explosion-proof valve in the third direction is The dimension of the exhaust passage in the third direction is , and satisfy: .

[0012] Preferably, each of the support plates is provided with a plurality of protrusions, the protrusions protruding from the side of the support plate facing the mounting body in the first direction toward the side of the mounting body, and the plurality of protrusions are arranged at intervals along the third direction; The support plate has multiple grooves, which are recessed from the support surface toward the interior of the support plate. The multiple grooves on the support plate correspond one-to-one with the multiple protrusions, and the grooves are directly opposite the protrusions corresponding to the grooves.

[0013] Preferably, the dimension of the protrusion in the first direction is , satisfy: ; And / or, the dimension of the groove in the first direction is , satisfy: .

[0014] According to another aspect of this application, a battery cell is provided, the battery cell including an electrode assembly and the aforementioned cover plate assembly, the electrode assembly including a contact surface and a clearance groove, the clearance groove being recessed from the contact surface toward the interior of the electrode assembly, and the support frame being located within the clearance groove.

[0015] Preferably, the battery cell further includes a support plate, the support plate including an insulating body and two extensions, the two extensions being connected to opposite ends of the insulating body, the insulating body covering the contact surface and the groove wall of the clearance groove, and the two extensions being abutted to opposite ends of the electrode assembly.

[0016] The cover plate assembly of this application includes an explosion-proof valve, a cover plate body, and a support frame. The cover plate body includes a mounting body and multiple mounting components. The mounting body has an installation opening extending through the mounting body along a first direction. The explosion-proof valve is disposed within the installation opening. The mounting components protrude from the mounting body and are divided into two groups, with the two groups of mounting components located on opposite sides of the explosion-proof valve. The support frame includes multiple support plates and two connecting components. The two ends of each support plate are connected to the two connecting components. The multiple support plates are arranged at intervals, with adjacent support plates forming an exhaust channel. The two connecting components are connected to the two groups of mounting components. A plane perpendicular to the first direction is defined as the projection plane, and the area of ​​the outer contour of the support frame projected onto the projection plane along the first direction is... The sum of the areas of the multiple exhaust channels is The thickness of the support plate in the first direction is , , and satisfy: This provides the support frame with sufficient strength to support the electrode assembly. In the event of thermal runaway in the cell, the explosion-proof valve opens, allowing high-temperature gas to flow through the exhaust channel and the gap between the edge of the support frame and the cover plate to the valve, where it is then discharged. Thus, by supporting the electrode assembly with the support frame, the electrode assembly is prevented from obstructing the explosion-proof valve, ensuring its effective venting and improving the cell's safety performance. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A three-dimensional structural schematic diagram of the cover plate assembly is shown; Figure 2 A schematic diagram of the planar structure of the cover plate assembly from one perspective is shown; Figure 3 A schematic diagram of the cover plate assembly from another perspective is shown. Figure 4 A three-dimensional structural diagram of the support frame is shown; Figure 5 A schematic diagram of the planar structure of the support frame from one perspective is shown; Figure 6 A schematic diagram of the planar structure of the support frame from another perspective is shown; Figure 7 A three-dimensional structural view of the cover plate body is shown; Figure 8 A schematic diagram of the planar structure of the cover plate body is shown; Figure 9 A three-dimensional structural diagram of the battery cell is shown; Figure 10 A partial structural diagram of the battery cell is shown; Figure 11 A diagram showing the relative positions of the support plate, electrode assembly, and insulating film; Figure 12 A three-dimensional structural diagram of the tray is shown; Figure 13 A schematic diagram of the planar structure of the tray is shown.

[0019] Reference numerals: 1-Explosion-proof valve; 2-Cover plate body; 21-Mounting body; 22-Mounting component; 221-First boss; 222-Second boss; 3-Support plate; 31-Insulating body; 311-Fitting part; 312-Extension part; 32-Extension component; 33-Exhaust hole; 34-Setting groove; 4-Adhesive layer; 5-Electrode assembly; 51-Electrode group; 52-Insulating film; 521-Vent hole; 53-Allowing groove; 54-Contact surface; 6-Support frame; 61-Support plate; 62-Connector; 621-Fixing part; 622-Connecting part; 63-Protrusion; 64-Groove; 65-Supporting plane; 66-Exhaust channel; 7-Shell; 8-Top cover; 9-Weld; F1-First direction; F2-Second direction; F3-Third direction. Detailed Implementation

[0020] The following detailed embodiments are provided to help the reader gain a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will be apparent after understanding the disclosure of this application. For example, the order of operations described herein is merely illustrative and is not limited to the order set forth herein; changes that will be apparent after understanding the disclosure of this application are possible, except for operations that must occur in a specific order. Furthermore, for clarity and brevity, descriptions of features known in the art may be omitted.

[0021] The features described herein may be implemented in different forms and should not be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0022] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, it may be directly "on" another element, "connected to" another element, "bonded to" another element, "on" another element, or "covering" another element, or there may be one or more other elements in between. In contrast, when an element is described as being "directly on" another element, "directly connected to" another element, "directly bonded to" another element, "directly on" another element, or "directly covering" another element, there may be no other elements in between.

[0023] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0024] Although terms such as “first,” “second,” and “third” may be used herein to describe individual components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts are not limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Therefore, without departing from the teachings of the examples described herein, the first component, assembly, region, layer, or part referred to as the second component, assembly, region, layer, or part may also be referred to as the second component, assembly, region, layer, or part.

[0025] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” are used herein to describe the relationship between one element and another, as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also different orientations of the device during use or operation. For example, if the device in the drawings is flipped, an element described as being “above” or “upper” relative to another element will subsequently be “below” or “lower” relative to that other element. Therefore, the term “above” includes both “above” and “below” orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relation terms used herein will be interpreted accordingly.

[0026] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0027] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0028] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have a wide variety of constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application.

[0029] The following will combine Figures 1 to 13 The cover plate assembly and the battery cell are described in detail. Figures 1 to 13In the middle, the first direction F1 is perpendicular to the second direction F2, and the third direction F3 is perpendicular to the plane determined by the second direction F2 and the first direction F1.

[0030] According to one aspect of this application, a cover plate assembly is provided, such as... Figures 1 to 8 As shown, the cover assembly includes an explosion-proof valve 1, a cover body 2, and a support frame 6. The cover body 2 includes a mounting body 21 and multiple mounting components 22. The mounting body 21 has an installation opening that extends through the mounting body 21 along the first direction F1. The explosion-proof valve 1 is disposed within the installation opening. The mounting components 22 protrude from the mounting body 21, and the multiple mounting components 22 are divided into two groups, with the two groups of mounting components 22 located on opposite sides of the explosion-proof valve 1. The support frame 6 includes multiple support plates 61 and two connecting components 62. The two ends of the support plates 61 are connected to the two connecting components 62 respectively. The multiple support plates 61 are arranged at intervals, and two adjacent support plates 61 form an exhaust channel 66. The two connecting components 62 are connected to the two groups of mounting components 22 respectively. The plane perpendicular to the first direction F1 is defined as the projection plane, and the area of ​​the outer contour of the projection of the support frame 6 along the first direction F1 onto the projection plane is... The sum of the areas of the multiple exhaust channels 66 is The thickness of the support plate 61 in the first direction F1 is , , and satisfy: This provides the support frame 6 with sufficient strength to support the electrode assembly 51. In the event of thermal runaway in the battery cell, the explosion-proof valve 1 opens, allowing high-temperature gas to flow through the exhaust channel 66 and the gap between the edge of the support frame 6 and the cover plate body 2 towards the explosion-proof valve 1, and then be discharged through it. Thus, by supporting the electrode assembly 51 with the support frame 6, the electrode assembly 51 is prevented from obstructing the explosion-proof valve 1, ensuring the effective venting of the explosion-proof valve 1 and improving the safety performance of the battery cell.

[0031] Optionally, , .

[0032] In addition, At that time, the area of ​​support frame 6 was too small, resulting in poor support effect for pole group 51 and poor exhaust effect during thermal runaway; At that time, the thickness of the support plate 61 The battery is too large; the support frame 6 occupies a significant amount of space, reducing the space available for the electrode assembly 51 and thus affecting the battery's capacity. At the same time, it can ensure the support effect of the support frame 6 pairs of pole groups 51 while ensuring the battery capacity.

[0033] Furthermore, such as Figure 3 and Figure 11As shown, the cover plate assembly faces the electrode assembly 5, and the area of ​​the outer contour of the projection of the electrode assembly 5 along the first direction F1 onto the projection plane is... , , The dimension of electrode assembly 5 in the second direction F2, The dimension of electrode assembly 5 in the third direction F3. Support plate 61 includes a support plane 65 on the side opposite to cover plate body 2 in the first direction F1, and the distance between support plane 65 and mounting body 21 in the first direction F1 is... , , and satisfy: .exist At that time, the area of ​​the outer contour of the support frame 6 The size is too small, resulting in poor support for the 6-pole assembly 51 and poor venting performance during thermal runaway. At that time, the distance between the supporting plane 65 and the mounting body 21 The size is too large; the support frame 6 occupies a large space in the first direction F1, reducing the space that the pole group 51 can occupy, thus affecting the cell capacity. At the same time, it can ensure the support effect of the support frame 6 pairs of pole groups 51 while ensuring the battery capacity.

[0034] Optionally, the distance between the supporting plane 65 and the mounting body 21 in the first direction F1 is... satisfy: .

[0035] Optionally, multiple support plates 61 can be arranged at intervals along the second direction F2, in which case the two ends of the support plates 61 on the third direction F3 are respectively connected to two sets of connectors 62; multiple support plates 61 can be arranged at intervals along the third direction F3, in which case the two ends of the support plates 61 on the second direction F2 are respectively connected to two sets of connectors 62.

[0036] Preferably, multiple support plates 61 are arranged at intervals along the second direction F2, and the two ends of the support plates 61 in the third direction F3 are respectively connected to two sets of connectors 62. The number of exhaust channels 66 can be two, three or more, preferably three.

[0037] like Figure 8 As shown, the dimension of explosion-proof valve 1 in the second direction F2 is The dimension of explosion-proof valve 1 on the third direction F3 is , and satisfy: , The effective opening area of ​​explosion-proof valve 1 is , satisfy: .

[0038] like Figure 4 , Figure 5 and Figure 6 As shown, each support plate 61 is provided with multiple protrusions 63. The protrusions 63 protrude from the side of the support plate 61 facing the mounting body 21 in the first direction F1 toward the side of the mounting body 21, and the multiple protrusions 63 are arranged at intervals along the third direction F3. The support plate 61 is provided with multiple grooves 64. The grooves 64 are recessed from the support plane 65 toward the interior of the support plate 61. The multiple grooves 64 on the support plate 61 correspond one-to-one with the multiple protrusions 63, and the grooves 64 are directly opposite the protrusions 63 corresponding to the grooves 64. In this way, the support plate 61 is provided with protrusions 63 and grooves 64, which can improve the structural strength of the support plate 61, thereby ensuring the support effect of the support frame 6 on the pole group 51.

[0039] Preferably, the dimension of the protrusion 63 in the first direction F1 is , satisfy: The dimension of groove 64 in the first direction F1 is , satisfy: .

[0040] Preferably, the support frame 6 can be made of aluminum, and the entire support frame 6 is integrally formed.

[0041] like Figure 4 , Figure 5 and Figure 6 As shown, the connector 62 includes a connecting part 622 and a fixing part 621 connected to each other. The fixing part 621 protrudes towards the mounting body 21 relative to the connecting part 622. The two ends of the support plate 61 in the third direction F3 are respectively connected to the two connecting parts 622 of the two connectors 62. The two fixing parts 621 of the two connectors 62 are respectively welded to the two sets of mounting parts 22 to form a weld 9, thereby realizing the fixation of the support frame 6.

[0042] Optionally, the number of mounting parts 22 in each group can be selected according to requirements, and the number of mounting parts 22 in each group can be one, two, three or more. The number of support plates 61 can be three, four or more. Preferably, the number of mounting parts 22 in each group is two, and the number of support plates 61 is four, with the two support plates 61 located at the edge being connected to the two ends of the connecting part 622 in the second direction F2, respectively.

[0043] like Figure 1 , Figure 7 and Figure 8As shown, the mounting component 22 includes a first boss 221 and a second boss 222. The first boss 221 protrudes from the mounting body 21, and the second boss 222 protrudes from the first boss 221. The fixing part 621 is attached to the side of the first boss 221 facing away from the mounting body 21 in the first direction F1. The fixing part 621 is attached to the side of the second boss 222 facing the connecting part 622 in the third direction F3. The surface of the second boss 222 facing away from the mounting body 21 in the first direction F1 is flush with the surface of the fixing part 621 facing away from the mounting body 21 in the first direction F1. The second boss 222 and the fixing part 621 are welded together to form a weld 9.

[0044] Optionally, the weld penetration depth between the second boss 222 and the fixing part 621 is... , melt width is , , This is to ensure the welding effect between the second boss 222 and the fixing part 621.

[0045] Preferably, the thickness of the mounting body 21 is 2.0 .

[0046] Furthermore, such as Figure 7 As shown, the dimension of the first boss 221 in the first direction F1 is... , The first boss 221 cooperates with the fixing part 621, so that there is a certain distance between the support plate 61 and the mounting body 21, so that high-temperature gas can flow to the explosion-proof valve 1 through the gap between the edge of the support frame 6 and the mounting body 21. The dimension of the second boss 222 in the first direction F1 is... The dimensions of the second boss 222 in the first direction F1 Equal to the thickness of the connecting part 622 ,Right now = This is such that the surface of the second protrusion 222 facing away from the mounting body 21 in the first direction F1 is flush with the surface of the fixing part 621 facing away from the mounting body 21 in the first direction F1. .

[0047] Furthermore, the distance between the mounting component 22 and the explosion-proof valve 1 in the third direction F3 is... , satisfy: .exist At that time, the gap between the mounting part 22 and the explosion-proof valve 1 was too small. When the mounting part 22 was processed by stamping, it affected the flatness of the installation position of the explosion-proof valve 1, thus affecting the welding yield of the explosion-proof valve 1. At that time, the span of the support frame 6 was relatively large, and the support effect of the two sets of mounting parts 22 on the pole group 51 was poor, which in turn led to the poor support effect of the support frame 6 on the pole group 51. This can reduce the impact of machining and installing the parts 22 on the welding of the explosion-proof valve 1, while ensuring the support effect of the parts 22 on the support frame 6.

[0048] Select rated discharge energy for Rated charging power for Rated voltage for Ten groups of battery cells were subjected to thermal runaway performance tests. The parameters of the ten cells in each group were identical, while the parameters of the cells in different groups were different. , , , , and The values ​​are shown in the table below.

[0049] Test environment: The battery cell under test is placed in the thermal runaway test apparatus. A sheet-like heating element is arranged on the largest surface area of ​​the battery cell. The size of the sheet-like heating element is no larger than the area of ​​the largest surface area of ​​the battery cell, and the power of the heating element needs to be greater than [missing information]. (For example, the power of the heating element can be) ); Test equipment: A temperature sensor with a diameter of less than 1 mm is placed at the center of the other surface with the largest area in the battery cell. The temperature sampling period is set to 1 second, and the test is set to continuously detect three temperature rise rate values ​​that are greater than or equal to... Alternatively, fire or explosion can be used as the criteria for determining thermal runaway. The test cell is then connected to the charging and discharging device and its voltage data sampling line. Experimental method: Perform constant current charging, start heating, and record time, voltage, current, temperature, and rate of temperature rise. Record experimental phenomena, including expansion, leakage, smoke, fire, explosion, shell rupture, and rupture location; trigger the judgment condition for thermal runaway or when the temperature reaches... Or the test time reaches When the time is up, stop the power supply and heating, observe for 1 hour, and record the time, voltage, current, temperature, and rate of temperature rise. Record the test phenomena, including expansion, leakage, smoke, fire, explosion, shell cracking, crack location, electrode group movement, and support frame deformation.

[0050] The test results of 10 groups of battery cells are as follows:

[0051] Based on the table above, it can be seen that... At that time, the area of ​​support frame 6 was too small, affecting the overall structural strength of support frame 6, and some battery cells could not pass the safety test; At that time, the area of ​​the outer contour of the support frame 6 The size is too small, resulting in poor support for the 6-pole assembly 51 and poor venting performance during thermal runaway. ,and At the same time, it can simultaneously take into account the support effect and the exhaust efficiency in the event of thermal runaway. In the event of thermal runaway, the explosion-proof valve 1 can open normally, the pole group 51 will not move significantly, and the support frame 6 will not deform, and the strength meets the requirements.

[0052] According to another aspect of this application, a battery cell is provided, such as... Figures 9 to 13 As shown, the battery cell includes an electrode assembly 5 and the aforementioned cover plate assembly. The electrode assembly 5 includes a contact surface 54 and a clearance groove 53. The clearance groove 53 is recessed from the contact surface 54 toward the interior of the electrode assembly 5, and the support frame 6 is located within the clearance groove 53.

[0053] Preferably, the first direction F1 is parallel to the length direction of the battery cell, the second direction F2 is parallel to the width direction of the battery cell, and the third direction F3 is parallel to the thickness direction of the battery cell.

[0054] like Figure 9 As shown, the battery cell also includes a housing 7 and a top cover 8. The electrode assembly 5 is disposed inside the housing 7. The two ends of the housing 7 in the first direction F1 are welded to the top cover 8 and the cover plate body 2, respectively.

[0055] like Figure 10 and Figure 11As shown, the battery cell also includes a support plate 3, which includes an insulating body 31 and two extensions 32. The two extensions 32 are respectively connected to both ends of the insulating body 31 in the second direction F2. The insulating body 31 has multiple vent holes 33. The insulating body 31 is attached to the side of the electrode assembly 5 facing the cover plate assembly in the first direction F1. The two extensions 32 are respectively attached to both sides of the electrode assembly 5 in the second direction F2. The electrode assembly 5 and the support plate 3 are interference-fitted. The support plate 3 can achieve insulation between the electrode assembly 5 and the support plate 61, and between the electrode assembly 5 and the cover plate body 2. When the battery cell experiences thermal runaway and the support plate 3 does not melt, the explosion-proof valve 1 opens, and high-temperature gas can flow out from the vent holes 33. Then, it flows through the exhaust channel 66 and the gap between the edge of the support frame 6 and the mounting body 21 to the explosion-proof valve 1, and is then discharged through the explosion-proof valve 1. When thermal runaway occurs in the battery cell and the support plate 3 melts, the support plate 61 can support the electrode assembly 5. High-temperature gas can flow to the explosion-proof valve 1 through the exhaust channel 66 and the gap between the edge of the support frame 6 and the mounting body 21, and then be discharged through the explosion-proof valve 1. Since the support frame 6 can support the electrode assembly 5, this can prevent the electrode assembly 51 from blocking the explosion-proof valve 1. In this way, the exhaust effect of the explosion-proof valve 1 is guaranteed, and the safety performance of the battery cell is improved.

[0056] In addition, the tray 3 can serve as insulation, eliminating the need for plastic parts and improving the space utilization of the battery cell casing 7.

[0057] Optionally, the thickness of pallet 3 is , The pallet 3 can be made of PP (Polypropylene). The tensile strength of the material of the pallet 3 is greater than 50 MPa, the elastic modulus is greater than 1100 MPa, and the elongation is greater than 85%. The entire pallet 3 is integrally molded.

[0058] In the embodiments of this application, such as Figure 11As shown, the electrode assembly 5 includes an electrode group 51 and an insulating film 52. A groove is formed on the side of the electrode group 51 facing the cover plate assembly. The shape of the insulating film 52 is adapted to the shape of the electrode group 51, so that the electrode assembly 5 forms a relief groove 53. The surface of the insulating film 52 facing the cover plate assembly is a contact surface 54. The relief groove 53 is recessed into the interior of the electrode assembly 5 relative to the contact surface 54. The insulating body 31 includes an extension 312 and two fitting portions 311. The two fitting portions 311 are respectively connected to the two ends of the extension 312 in the second direction F2. At least one of the extension 312 and the two fitting portions 311 has an exhaust hole 33. The extension 312 protrudes from the side away from the cover plate body 2 relative to the fitting portions 311. The fitting portions 311 fit against the contact surface 54. The extension 312 extends into the clearance groove 53 and contacts the groove wall of the clearance groove 53. A mounting groove 34 is formed on the side of the extension 312 opposite to the electrode assembly 51, and the support frame 6 is located in the mounting groove 34. In this way, the electrode assembly 51 is configured with a groove, so that the electrode assembly 5 forms a clearance groove 53. The extension portions 312 of the support frame 6 and the tray 3 are both located in the clearance groove 53. In the limited space of the housing 7, the electrode assembly 51 can occupy a large space, which ensures the capacity of the battery cell.

[0059] In addition, a vent hole 521 is provided on the insulating film 52 so that the gas inside the insulating film 52 can be discharged through the vent hole 521.

[0060] Optionally, the end face of the electrode assembly 51 on the side in the second direction F2 is the bonding surface. A vent hole 521 is provided in the area where the insulating film 52 is bonded to the bonding surface. The area where the insulating film 52 is bonded to the end face of the electrode assembly 51 facing the cover plate assembly is divided into three regions. The first region is bonded to the groove wall of the electrode assembly 51. The second and third regions are located on opposite sides of the first region in the second direction F2, respectively. Vent holes 521 are provided in both the first and second regions. When the battery cell is in use, the bonding surface and the second region are located on the upper side, and the third region is located on the lower side to prevent electrode powder from falling into the housing 7.

[0061] In addition, an exhaust hole 33 is provided on the extension 312 and on the fitting portion 311 that is in contact with the second region, so as to facilitate exhaust in case of thermal runaway. The diameter of the exhaust hole 33 is greater than or equal to 4 mm and less than or equal to 6 mm, and the total area of ​​the exhaust hole 33 accounts for 3%-6% of the surface area of ​​the insulating body 31 facing the electrode assembly 5.

[0062] Optionally, such as Figure 11 , Figure 12 and Figure 13 As shown, the dimension of electrode assembly 5 in the second direction F2 is When the support plate 3 is not assembled onto the electrode assembly 5, the dimension of the support plate 3 in the second direction F2 is: , and satisfy: This ensures that the support plate 3 and the electrode assembly 5 are interference-fitted, thereby guaranteeing the assembly stability of the support plate 3 while avoiding damage to the electrode sheets in the electrode assembly 51.

[0063] Furthermore, the dimension of electrode assembly 5 on the third direction F3 is... The dimensions of tray 3 on the third direction F3 are: , and satisfy: In this way, the support plate 3 can be prevented from protruding relative to the electrode assembly 5 while ensuring the insulation effect on the electrode assembly 5, so that the electrode assembly 5 and the support plate 3 can be installed into the housing 7 during the cell manufacturing process.

[0064] like Figure 12 As shown, the battery cell also includes multiple adhesive layers 4. One side of the adhesive layer 4 is bonded to the electrode assembly 5, and the other side of the adhesive layer 4 is bonded to the support plate 3. In this way, by setting the adhesive layer 4, the stability of the support plate 3 can be improved, so as to ensure the insulation effect between the electrode assembly 5 and the mounting body 21 and between the electrode assembly 5 and the support plate 61.

[0065] Optionally, the total area of ​​the three sides of the tray facing the electrode assembly 51 is The total area of ​​the support plate 3 facing the pole group 51 here This is the sum of the area where the vent 33 is located, the area where it is bonded to the adhesive layer 4, and the areas of other areas facing the electrode assembly 5. The sum of the areas where the tray 3 is bonded to the multiple adhesive layers 4 is... . and satisfy: This reduces costs while ensuring adhesive stability.

[0066] Optionally, the number of adhesive layers 4 can be four, with one adhesive layer 4 attached to each extension 32 and two adhesive layers 4 attached to the location of the extension 312.

[0067] Optionally, the adhesive layer 4 is made of an insulating adhesive that is resistant to temperature and electrolyte and has good stability. The temperature range of the insulating adhesive is -40℃ to 85℃. The insulating adhesive has been tested according to GB / T2792-2014 standard and has a 180° peel force greater than 35N. According to ASTM D3654 standard test, the holding force meets the requirement of not falling off for more than 60 hours. According to GB / T31125-2014 standard test, the initial tack force is greater than 25N to ensure the bonding effect of the adhesive layer 4.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A cover plate assembly, characterized in that, The cover plate assembly includes an explosion-proof valve, a cover plate body, and a support frame. The cover plate body includes an installation body and multiple mounting components. The installation body has an installation opening that extends through the installation body in a first direction. The explosion-proof valve is disposed in the installation opening. The mounting components protrude from the installation body. The multiple mounting components are divided into two groups, and the two groups of mounting components are located on both sides of the explosion-proof valve. The support frame includes multiple support plates and two connectors. The two ends of each support plate are connected to the two connectors respectively. The multiple support plates are arranged at intervals. Two adjacent support plates form an exhaust channel. The two connectors are connected to two sets of mounting components respectively. Define the plane perpendicular to the first direction as the projection plane, and the area of ​​the outer contour of the projection of the support frame along the first direction onto the projection plane is... The sum of the areas of the plurality of exhaust channels is The thickness of the support plate in the first direction is , , and satisfy: .

2. The cover plate assembly according to claim 1, characterized in that, The cover plate assembly faces the electrode assembly, and the area of ​​the outer contour of the electrode assembly projected onto the projection plane along the first direction is... The support plate includes a support plane facing away from the cover plate body in the first direction, and the distance between the support plane and the mounting body in the first direction is... , , and satisfy: .

3. The cover plate assembly according to claim 2, characterized in that, Multiple support plates are arranged at intervals along the second direction. The connector includes a connecting part and a fixing part connected to each other. The fixing part protrudes towards the mounting body relative to the connecting part. The two ends of the support plate in the third direction are respectively connected to two connecting parts of two connectors. The two fixing parts of the two connectors are respectively connected to two sets of mounting parts. The first direction is perpendicular to the second direction. The third direction is perpendicular to the plane determined by the first direction and the second direction.

4. The cover plate assembly according to claim 3, characterized in that, The mounting component includes a first boss and a second boss. The first boss protrudes from the mounting body, and the second boss protrudes from the first boss. The surface of the fixing part facing the mounting body in the first direction is fitted with the side of the first boss facing away from the mounting body in the first direction. The side of the fixing part facing away from the connecting part in the third direction is fitted with the side of the second boss facing the connecting part in the third direction. The surface of the second boss facing away from the mounting body in the first direction is flush with the surface of the fixing part facing away from the mounting body in the first direction.

5. The cover plate assembly according to claim 4, characterized in that, The distance between the mounting component and the explosion-proof valve in the third direction is , satisfy: .

6. The cover plate assembly according to claim 3, characterized in that, The explosion-proof valve has a dimension in the third direction. The dimension of the exhaust passage in the third direction is , and satisfy: .

7. The cover plate assembly according to claim 3, characterized in that, Each of the support plates is provided with a plurality of protrusions, which protrude from the side of the support plate facing the mounting body in the first direction toward the side of the mounting body, and the plurality of protrusions are arranged at intervals along the third direction. The support plate has multiple grooves that are recessed from the support plane toward the interior of the support plate. Each groove corresponds to a protrusion, and the groove is directly opposite the protrusion corresponding to the groove.

8. The cover plate assembly according to claim 7, characterized in that, The dimension of the protrusion in the first direction is: , satisfy: ; And / or, the dimension of the groove in the first direction is , satisfy: .

9. A battery cell, characterized in that, The battery cell includes an electrode assembly and a cover plate assembly according to any one of claims 1-8. The electrode assembly includes a contact surface and a clearance groove, the clearance groove being recessed from the contact surface toward the interior of the electrode assembly, and the support frame being located within the clearance groove.

10. The battery cell according to claim 9, characterized in that, The battery cell also includes a support plate, which includes an insulating body and two extensions. The two extensions are respectively connected to the two opposite ends of the insulating body. The insulating body covers the contact surface and the groove wall of the clearance groove. The two extensions are respectively attached to the two opposite ends of the electrode assembly.

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