Battery cells and battery packs

Abstract

The present invention relates to the field of battery technology, and in particular to a battery cell and a battery pack. The battery cell comprises: a first cover plate having an exhaust hole and a convex portion protruding toward the interior of the battery cell; a pressure relief member is mounted on the exhaust hole; a support member is mounted on the convex portion, so that the support member is spaced apart from the first cover plate, and the projection of the support member on the first cover plate covers the exhaust hole; a first ventilation area is formed on the support member, and gas can flow to the exhaust hole through the first ventilation area; the dimensions of the pressure relief member and the first ventilation area in the first direction are L1 and L2 respectively; the dimensions of the pressure relief member and the first ventilation area in the second direction are W1 and W2 respectively; 1.15≤L2 / L1≤1.3; 1.15≤W2 / W1≤1.3. In the present invention, even if displacement occurs inside the electrode group battery cell, the support member can prevent the electrode group from moving toward the exhaust hole, thereby preventing the electrode group from blocking or even completely blocking the exhaust hole.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell and a battery pack. Background Art

[0002] Lithium-ion batteries have become the representative of modern high-performance batteries due to their advantages such as high operating voltage, high specific energy, large capacity, low self-discharge, good cycle performance, long service life, light weight and small size.

[0003] Long cell lithium ion battery Figure 1 As shown, its structure includes: a cover plate 2, a shell 4, a bare cell insulating film 7, an electrode assembly 1, and an electrolyte. After the cover plate 2 and shell 4 are welded, they form a sealed space with a certain mechanical strength to protect the electrode assembly 1. The electrode assembly 1 is welded and fixed to the pole 6 on the cover plate 2 via the tabs, achieving electrical connection. The bare cell insulating film 7 surrounds the electrode assembly 1 and is heat-fused to the lower plastic 3 on the cover plate 2 on both sides, thereby ensuring isolation and insulation between the electrode assembly 1 and the shell 4. The cover plate 2 is integrated with an explosion-proof valve 5 structure to directional discharge internal high-temperature and high-pressure gases in the event of thermal runaway due to an internal short circuit, thereby improving battery safety.

[0004] At present, the insulating material in the battery cell is generally made of pp (polypropylene), whose strength and high temperature resistance are far lower than the temperature when thermal runaway occurs. During thermal runaway, the insulating components in the battery cell are at least partially melted, resulting in an increase in the gap between the electrode assembly and the cover and shell. Since the high-temperature and high-pressure gas is directional exhausted in the direction where the explosion-proof valve is installed, the electrode group will move with the high-temperature and high-pressure airflow and block the explosion-proof valve on the cover, greatly reducing the exhaust effect of the explosion-proof valve, thereby affecting the safety performance of the battery cell and battery pack. Summary of the Invention

[0005] In view of this, the purpose of the present application is to provide a battery cell and a battery pack to solve the problem that the insulating components in the battery cell are prone to melting during thermal runaway, resulting in an increase in the gap between the electrode group and the cover plate and the shell, and the electrode group will move with the high-temperature and high-pressure airflow to block the explosion-proof valve on the cover plate, reducing the exhaust effect of the explosion-proof valve, thereby reducing the safety performance of the battery cell and the battery pack.

[0006] A first aspect of the present invention provides a battery cell, wherein the battery cell comprises:

[0007] case;

[0008] a pole group, disposed in the housing;

[0009] a first cover plate connected to the housing, the first cover plate being provided with an exhaust hole and a convex portion protruding toward the interior of the battery cell;

[0010] a pressure relief member, mounted on the exhaust hole;

[0011] a support member mounted on the convex portion such that the support member is spaced apart from the first cover plate, and a projection of the support member on the first cover plate covers the exhaust hole; a first ventilation area is formed on the support member;

[0012] The size of the pressure relief part in the first direction is L1, in mm; the size of the pressure relief part in the second direction is W1, in mm; the size of the first ventilation area in the first direction is L2, in mm; the size of the first ventilation area in the second direction is W2, in mm; 1.15≤L2 / L1≤1.3; 1.15≤W2 / W1≤1.3.

[0013] Preferably, on the surface of the first cover plate facing the interior of the battery core, the minimum distance between the protrusion and the exhaust hole is H, and H is ≥ 4 mm.

[0014] Preferably, the support member is formed into a plate-like structure parallel to the first cover plate, and the thickness dimension of the support member is t, 0.8 mm≤t≤1.5 mm.

[0015] Preferably, the first ventilation area is provided with a plurality of first through holes arranged in an array.

[0016] Preferably, it also includes:

[0017] An insulating protective member is arranged on the side of the first cover plate facing the interior of the battery cell, and the support member is arranged between the insulating protective member and the first cover plate. A second ventilation area is formed on the insulating protective member and is arranged opposite to the first ventilation area. The second ventilation area is provided with a second through hole, and the radial dimension of the second through hole is d2, in mm; the radial dimension of the first through hole is d1, in mm; 1.2≤d2 / d1≤2.

[0018] Preferably, the insulating protective member is further provided with an auxiliary exhaust area, and the auxiliary exhaust area is provided with auxiliary ventilation holes.

[0019] Preferably, there are multiple protrusions, which are spaced apart around the exhaust hole. Two adjacent protrusions, the support member and the first cover plate form an exhaust channel, and at least part of the gas flows to the exhaust hole through the exhaust channel.

[0020] Preferably, the support member is a metal member;

[0021] And / or, the support member is arranged at one end of the protrusion facing the interior of the battery cell.

[0022] Preferably, it also includes:

[0023] a second cover plate connected to the housing, wherein a mounting hole is formed on the second cover plate;

[0024] The pole is arranged in the mounting hole, and the pole includes a positive pole and a negative pole.

[0025] A second aspect of the present invention provides a battery pack comprising the battery cell described in any of the above technical solutions.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The battery cell of the present invention is provided with an exhaust hole on the first cover plate, and a convex portion protruding toward the interior of the battery cell is formed; the support member is installed on the convex portion so that the support member and the first cover plate are spaced apart, and the boss is away from the surface of the cover plate body, so that the support member and the cover plate body are spaced apart, and the projection of the support member on the first cover plate covers the exhaust hole and forms a first ventilation area, so that at least part of the gas flows to the exhaust hole through the first ventilation area, and even if the pole group is displaced inside the battery cell during thermal runaway, the support member can prevent the pole group from moving toward the direction close to the exhaust hole, thereby avoiding the situation where the pole group blocks the exhaust hole or even completely blocks the exhaust hole, and preventing internal combustion products from splashing outward during thermal runaway, thereby improving the safety performance of the battery cell. The size of the pressure relief part in the first direction is L1, the size of the pressure relief part in the second direction is W1, the size of the first ventilation area in the first direction is L2, the size of the first ventilation area in the second direction is W2, 1.15≤L2 / L1≤1.3, 1.15≤W2 / W1≤1.3. This arrangement can ensure the structural strength of the support plate while ensuring that the exhaust effect of the first ventilation area meets the pressure relief requirements, so that the battery cell can be smoothly exhausted in the case of thermal runaway, thereby improving the safety performance of the battery cell and battery pack.

[0028] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 Exploded diagram of the structure of a battery cell in the prior art;

[0031] Figure 2 An exploded diagram of the structure of a battery cell provided by an embodiment of the present invention;

[0032] Figure 3 An exploded view of the structure of the first cover plate, the support member and the insulating protection member in the battery cell provided in an embodiment of the present invention;

[0033] Figure 4 An exploded view of the structure of the first cover plate, the support member, and the insulating protection member in the battery cell provided by an embodiment of the present invention from another perspective;

[0034] Figure 5 A schematic diagram of the structure in which the support member of the battery cell provided by an embodiment of the present invention is installed on the first cover plate;

[0035] Figure 6 A schematic structural diagram of a battery cell according to an embodiment of the present invention, in which a support member is installed on a first cover plate from another perspective;

[0036] Figure 7 This is a schematic structural diagram of the first cover plate in the battery cell provided by an embodiment of the present invention.

[0037] Icons: 10-shell; 20-insulating film; 30-pole group; 31-positive electrode ear; 32-negative electrode ear; 40-first cover; 41-convex portion; 42-exhaust hole; 51-pressure relief member; 52-protective patch; 60-support member; 61-first ventilation area; 611-first through hole; 62-exhaust channel; 70-insulating protection member; 71-second ventilation area, 711-second through hole; 72-auxiliary exhaust area; 721-auxiliary ventilation hole; 80-second cover; 81-positive electrode column; 82-negative electrode column; 83-insulating member; 84-liquid injection hole; 1-electrode assembly; 2-cover; 3-lower plastic; 4-shell; 5-explosion-proof valve; 6-pole column; 7-bare cell insulation film; D1-first direction; D2-second direction. DETAILED DESCRIPTION

[0038] The following detailed description is provided to help the reader gain a comprehensive understanding of the methods, devices, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, devices, and / or systems described herein will be apparent upon 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. Rather, except for operations that must occur in a particular order, changes may be made that will be apparent upon understanding the disclosure of this application. Furthermore, descriptions of features known in the art may be omitted for clarity and brevity.

[0039] 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 possible ways to implement the methods, devices, and / or systems described herein that will be apparent upon understanding the disclosure of this application.

[0040] Throughout the specification, when an element (such as a layer, region, or substrate) is described as being “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, it may be directly “on,” “connected to,” “coupled to,” “over,” or “overlaying” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on,” “directly connected to,” “directly coupled to,” “directly over,” or “directly covering” another element, there may be no other elements intervening therebetween.

[0041] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0042] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are used only to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Thus, a first member, component, region, layer, or portion in the examples described herein may also be referred to as a second member, component, region, layer, or portion without departing from the teachings of the examples.

[0043] For ease of description, spatial relational terms such as "above," "upper," "below," and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element would subsequently be "below" or "lower" relative to the other element. Thus, the term "above" includes both the orientations "above" and "below," 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 relational terms used herein will be interpreted accordingly.

[0044] The terms used herein are intended only to describe various examples and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the singular is intended to include the plural. The terms "comprise," "include," and "have" list the presence of stated features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0045] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include changes in shapes that occur during manufacturing.

[0046] The features of the examples described herein can be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0047] According to a first aspect of the present invention, a battery cell is provided, which specifically includes a housing 10 , an electrode group 30 , a first cover plate 40 , a pressure relief member 51 and a support member 60 .

[0048] Hereinafter, the specific structure of the battery cell according to the present embodiment as described above will be described.

[0049] In this embodiment, if Figure 2 As shown, a cavity is formed inside the shell 10, and the electrode group 30 is arranged in the cavity inside the shell 10. The electrode group 30 can be formed by stacking or winding positive and negative electrode sheets. A positive electrode ear 31 and a negative electrode ear 32 are provided on the electrode group 30. The outside of the electrode group 30 is covered with an insulating film 20 to separate the shell 10 and the electrode group 30, thereby forming insulation protection.

[0050] In this embodiment, if Figure 2 As shown, the first cover plate 40 is formed into a plate-like structure, such as a rectangular plate-like structure. The first cover plate 40 is connected to the shell 10. The first cover plate 40 is arranged at the opening of the cavity of the shell 10. The first cover plate 40 is provided with an exhaust hole 42 and a protrusion 41 protruding toward the interior of the battery cell. The exhaust hole 42 is formed as a through hole penetrating in the thickness direction of the first cover plate 40. The pressure relief member 51 is installed in the exhaust hole 42. When the battery cell has thermal runaway, the pressure relief member 51 opens so that the gas inside the battery cell can diffuse to the outside of the battery cell through the exhaust hole 42. The pressure relief member 51 can be an explosion-proof valve.

[0051] In addition, in this embodiment, Figure 3As shown, a protective patch 52 is provided on the side of the first cover plate 40 facing the outside of the battery cell. The protective patch 52 can be an explosion-proof valve patch. The protective patch 52 covers part of the exhaust hole 42 to protect the pressure relief component 51 in the exhaust hole 42, avoiding damage to the pressure relief component 51 due to impact, which may cause the pressure relief component 51 to open prematurely. The protective patch 52 only covers part of the exhaust hole 42, so that the outside of the battery cell can be connected to the pressure relief component 51 for detection, such as helium detection.

[0052] Furthermore, in this embodiment, Figures 3 to 5 and Figure 7 As shown, the protrusion 41 is formed into a convex block structure, and the support member 60 is installed on the protrusion 41, so that the support member 60 is spaced apart from the first cover plate 40, and the projection of the support member 60 on the first cover plate 40 covers the exhaust hole 42. In the event of thermal runaway, even if the electrode group 30 is displaced inside the battery cell, the support member 60 can prevent the electrode group 30 from continuing to move toward the exhaust hole 42, thereby avoiding the situation where the electrode group 30 blocks the exhaust hole 42 or even completely blocks it, and preventing internal combustion products from splashing outward during thermal runaway, thereby improving the safety performance of the battery cell.

[0053] In this embodiment, if Figures 3 to 7 As shown, a first ventilation area 61 is formed on the support member 60, so that at least part of the gas flows to the exhaust hole 42 through the first ventilation area 61, and the size of the pressure relief member 51 in the first direction D1 is L1, and the unit is mm; the size of the pressure relief member 51 in the second direction D2 is W1, and the unit is mm; the size of the first ventilation area 61 in the first direction D1 is L2, and the unit is mm; the size of the first ventilation area 61 in the second direction D2 is W2, and the unit is mm; 1.15≤L2 / L1≤1.3; 1.15≤W2 / W1≤1.3, such a setting can ensure that the exhaust effect of the first ventilation area 61 meets the pressure relief requirements while ensuring the structural strength of the support plate, so that the battery cell can be smoothly exhausted in the case of thermal runaway, thereby improving the safety performance of the battery cell.

[0054] The following multiple groups of safety tests are conducted on battery cells with different L1, L2, W1 and W2 to detect whether the limiting conditions of 1.15≤L2 / L1≤1.3 and 1.15≤W2 / W1≤1.3 can ensure the exhaust requirements in the event of thermal runaway of the battery cells. Five groups of similar battery cells are used in each group of tests to ensure the reliability and accuracy of the test results. The test results are shown in Table 1 below.

[0055] Table 1

[0056]

[0057]

[0058] As can be seen from Table 1, in Examples 1-1 to 1-3, the ratio of the size of the first ventilation area 61 to the size of the pressure relief member 51 has a direct impact on the exhaust effect. In Examples 1-4 to 1-7, when 1.15≤L2 / L1≤1.3 and 1.15≤W2 / W1≤1.3 are satisfied, the support member 60 takes into account both exhaust and strength requirements, and the pass rate of the battery cell safety test is significantly increased. However, in Example 1-8, the excessive size of the support member 60 will affect the structural strength.

[0059] It should be noted that, in this embodiment, the first direction D1 is perpendicular to the second direction D2. When the first cover plate 40 is a rectangular plate structure, the first direction D1 can be the length direction of the first cover plate 40, and the second direction D2 can be the width direction of the first cover plate 40. When the exhaust hole 42 is a long hole, the first direction D1 can be the length direction of the exhaust hole 42, and the second direction D2 is the width direction of the exhaust hole 42.

[0060] In this embodiment, the support member 60 is a metal member, for example, the support member 60 and the first cover plate 40 are both made of aluminum; the support member 60 and the protrusion 41 are welded together, and the protrusion 41 is preferably formed on the first cover plate 40 through a stamping process, which is simple to prepare, low in cost, and reduces the battery cell assembly process.

[0061] In this embodiment, the support member 60 is provided at one end of the convex portion 41 facing the inside of the battery cell, so as to increase the contact area between the support member 60 and the convex portion 41 and ensure that the support member 60 and the convex portion 41 are firmly connected. Preferably, the total area of ​​the projection of the convex portion 41 on the first cover plate 40 is 400 mm. 2 Up to 900mm 2 The total area of ​​the projections of all the protrusions 41 on the first cover plate 40 in the direction perpendicular to the thickness of the first cover plate 40 is 400 mm. 2 Up to 900mm 2 , thus ensuring that the protrusion 41 can effectively support the support member 60.

[0062] In a preferred embodiment, Figure 4 As shown, on the surface of the first cover plate 40 facing the interior of the battery cell, the minimum distance between the protrusion 41 and the exhaust hole 42 is H, H≥4mm, so as to prevent the welding of the support member 60 and the protrusion 41 from affecting the opening of the pressure relief member 51.

[0063] The following tests are conducted on the opening pressure values ​​of multiple groups of pressure relief members 51 for battery cells with different sizes H. The opening pressure of the pressure relief member 51 is designed to be 0.9 MPa. The data of the actual opening pressure of the pressure relief member 51 at different H distances are compared. Multiple groups of similar battery cells are used in each test to ensure the reliability and accuracy of the test results. The test results are shown in Table 2 below.

[0064] Table 2

[0065]

[0066] As shown in Table 2, in Examples 2-1 to 2-3, since the position of the protrusion 41 on the first cover plate 40 is close to the position of the exhaust hole 42, the welding connection between the support member 60 and the protrusion 41 will affect the normal opening of the pressure relief member 51; while in Examples 2-4 to 2-8, the welding of the support member 60 has no obvious effect on the opening pressure of the pressure relief member 51, meeting the design requirements.

[0067] In this embodiment, if Figure 4 As shown, the support member 60 is formed into a plate-like structure parallel to the first cover plate 40. The thickness of the support member 60 is t, and 0.8mm≤t≤1.5mm. This ensures that the support member 60 has sufficient structural strength to prevent the electrode group 30 from blocking or blocking the pressure relief member 51, and prevents t from being too large, which would occupy the internal space of the battery cell and affect the energy density of the battery cell. Specifically, when the battery cell is a ternary system or energy storage system, 1.1mm≤t≤1.5mm, and when the battery cell is an iron-lithium system, 0.8mm≤t≤1.1mm.

[0068] Next, multiple groups of battery cell safety tests were conducted on battery cells with different sizes t to detect whether support members 60 with different thicknesses were deformed after the tests. The test results are shown in Table 3 below.

[0069] Table 3

[0070] system t / mm Test results Example 3-1 Ternary / Energy Storage 1.0 The support is not strong enough. After disassembling the battery cell, it was found that the support was deformed. Example 3-2 Ternary / Energy Storage 1.1 No deformation of support parts Example 3-3 Ternary / Energy Storage 1.2 No deformation of support parts Examples 3-4 Ternary / Energy Storage 1.5 No deformation of support parts Examples 3-5 Ternary / Energy Storage 1.6 No deformation of support parts Examples 3-6 Iron lithium 1.0 No deformation of support parts Examples 3-7 Iron lithium 0.9 No deformation of support parts Examples 3-8 Iron lithium 0.8 No deformation of support parts Examples 3-9 Iron lithium 0.7 The support is not strong enough. After disassembling the battery cell, it was found that the support was deformed.

[0071] As shown in Table 3, in Example 3-1 and Example 3-9, the support member 60 is not strong enough, and after the battery cells are disassembled, it is found that the support member 60 is deformed. In Example 3-2 to Example 3-8, the support member 60 has no deformation problem. Therefore, the thickness of the support member 60 in the battery cells of the iron-lithium system needs to be greater than or equal to 0.8 mm, and the thickness of the support member 60 in the battery cells of the ternary / energy storage system needs to be greater than or equal to 1.1 mm to ensure that the strength of the support member 60 meets the requirements and will not be deformed during the battery cell safety test.

[0072] In this embodiment, if Figures 2 to 7 As shown, the first ventilation area 61 is provided with a plurality of first through holes 611 arranged in an array, thereby ensuring that the support member 60 has sufficient structural strength and meets the exhaust requirements. The first through holes 611 can be circular through holes. The plurality of first through holes 611 can be arranged in an array in a rectangular, circular, or similar shape to the exhaust holes 42.

[0073] In this embodiment, if Figure 5As shown, the battery cell also includes an insulating protective member 70, which is arranged on the side of the first cover plate 40 facing the interior of the battery cell, and the support member 60 is arranged between the insulating protective member 70 and the first cover plate 40, so as to separate the pole group 30 from the first cover plate 40 and the support member 60 to form an insulating protection, and a second ventilation area 71 is formed on the insulating protective member 70 and is arranged opposite to the first ventilation area 61. The second ventilation area 71 is provided with a second through hole 711, and the radial dimension of the second through hole 711 is d2, in mm; the radial dimension of the first through hole 611 is d1, in mm; 1.2≤d2 / d1≤2, so that when the temperature is low, the insulating protective member 70 has sufficient strength while meeting the exhaust requirements, ensuring smooth exhaust and unaffected exhaust rate, and can also prevent internal combustion products from splashing outward during thermal runaway, thereby improving the safety performance of the battery cell.

[0074] Furthermore, in this embodiment, Figures 3 to 5 As shown, the insulating protective member 70 is also provided with an auxiliary exhaust area 72, and the auxiliary exhaust area 72 is provided with auxiliary ventilation holes 721. Preferably, a plurality of auxiliary ventilation holes 721 are provided on the auxiliary exhaust area 72, and the auxiliary ventilation holes 721 are formed as strip holes, and the area of ​​the auxiliary ventilation holes 721 is larger than the area of ​​the first through hole 611 and the second through hole 711, so as to accelerate the exhaust in the event of thermal failure and quickly alleviate thermal runaway.

[0075] Specifically, the auxiliary exhaust region 72 is provided on the side of the second ventilation region 71 . Preferably, when the insulating protection member 70 is formed into a rectangular plate-like structure, auxiliary exhaust regions 72 are provided on both sides of the insulating protection member 70 in the length direction.

[0076] In a preferred embodiment, Figure 5 and Figure 7 As shown, there are multiple protrusions 41, and the multiple protrusions 41 are arranged at intervals around the exhaust hole 42. Two adjacent protrusions 41, the support member 60 and the first cover plate 40 form an exhaust channel 62. At least part of the gas flows to the exhaust hole 42 through the exhaust channel 62, thereby further accelerating the discharge of gas inside the battery cell.

[0077] In this embodiment, if Figure 4 As shown, in the thickness direction of the first cover plate 40, the height dimension of the protrusion 41 is A, 1mm≤A≤2mm, so that the protrusion 41 separates the first cover plate 40 and the support member 60, and the support member 60 is formed into a plate-like structure parallel to the first cover plate 40, avoiding excessive occupation of the internal space of the battery cell while ensuring the need for rapid exhaust of the battery cell.

[0078] In addition, in this embodiment, Figure 2As shown, the battery cell also includes a second cover plate 80, a pole and an insulating member 83. The second cover plate 80 is connected to the shell 10. The second cover plate 80 is provided with a mounting hole and a liquid injection hole 84. After the battery cell is assembled, the electrolyte is injected into the battery cell and the vacuum is drawn through the liquid injection hole 84. The pole is arranged in the mounting hole. The pole includes a positive pole 81 and a negative pole 82. The positive pole 81 is connected to the positive ear 31, and the negative pole 82 is connected to the negative ear 32. The insulating member 83 is arranged on the side of the second cover plate 80 facing the inside of the battery cell, and is used to separate the second cover plate 80 from the conductive components inside the battery cell, thereby forming insulation protection. The insulating film 20 as described above can be hot-melt connected to the insulating member 83 and the insulating protection member 70, so as to separate the conductive components inside the battery cell from the shell 10 and the cover plate of the battery cell, thereby reducing the risk of short circuit.

[0079] Preferably, the first cover plate 40 and the second cover plate 80 are arranged at both ends of the housing 10, so that one side of the battery cell is used for electrical connection and the other side is used for pressure relief protection during thermal runaway, thereby improving the safety performance of the battery cell.

[0080] According to a battery cell provided by the present invention, an exhaust hole is opened on the first cover plate, and a convex portion protruding toward the interior of the battery cell is formed; the support member is installed on the convex portion so that the support member and the first cover plate are spaced apart, and the boss is away from the surface of the cover plate body, so that the support member and the cover plate body are spaced apart, and the projection of the support member on the first cover plate covers the exhaust hole and forms a first ventilation area, so that at least part of the gas flows to the exhaust hole through the first ventilation area, and even if the pole group is displaced inside the battery cell during thermal runaway, the support member can prevent the pole group from moving toward the exhaust hole, thereby avoiding the pole group blocking or even completely blocking the exhaust hole, and preventing internal combustion products from splashing outward during thermal runaway, thereby improving the safety performance of the battery cell. The size of the pressure relief part in the first direction is L1, the size of the pressure relief part in the second direction is W1, the size of the first ventilation area in the first direction is L2, the size of the first ventilation area in the second direction is W2, 1.15≤L2 / L1≤1.3, 1.15≤W2 / W1≤1.3. This arrangement can ensure the structural strength of the support plate while ensuring that the exhaust effect of the first ventilation area meets the pressure relief requirements, so that the battery cell can be smoothly exhausted in the case of thermal runaway, thereby improving the safety performance of the battery cell.

[0081] A battery pack provided by the present invention includes the battery cell described above. By providing a support member, the exhaust hole is prevented from being blocked or blocked by the electrode group during thermal runaway, thereby ensuring smooth exhaust and improving the safety performance of the battery pack.

[0082] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The scope of protection of the present application is not limited thereto. Although the present application has been described in detail with reference to the above-described embodiments, those skilled in the art should understand that any person skilled in the art can modify or easily conceive of changes to the technical solutions described in the above-described embodiments within the technical scope disclosed in the present application, or perform equivalent replacements for some of the technical features thereof. These modifications, changes, or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the scope of protection of the claims.

Claims

1. A battery cell, characterized in that: The battery cell comprises: case; a pole group, disposed in the housing; a first cover plate connected to the housing, the first cover plate being provided with an exhaust hole and a convex portion protruding toward the interior of the battery cell; a pressure relief member, mounted on the exhaust hole; a support member mounted on the convex portion such that the support member is spaced apart from the first cover plate, and a projection of the support member on the first cover plate covers the exhaust hole; a first ventilation area is formed on the support member; The size of the pressure relief part in the first direction is L1, in mm; the size of the pressure relief part in the second direction is W1, in mm; the size of the first ventilation area in the first direction is L2, in mm; the size of the first ventilation area in the second direction is W2, in mm; 1.15≤L2 / L1≤1.3; 1.15≤W2 / W1≤1.

3.

2. The battery cell according to claim 1, characterized in that On a surface of the first cover plate facing the interior of the battery core, a minimum distance between the protrusion and the exhaust hole is H, where H is ≥ 4 mm.

3. The battery cell according to claim 1, characterized in that The support member is formed into a plate-shaped structure parallel to the first cover plate, and the thickness dimension of the support member is t, 0.8 mm≤t≤1.5 mm.

4. The battery cell according to claim 1, characterized in that The first ventilation area is provided with a plurality of first through holes arranged in an array.

5. The battery cell according to claim 4, characterized in that: Also includes: An insulating protective member is arranged on the side of the first cover plate facing the interior of the battery cell, and the support member is arranged between the insulating protective member and the first cover plate. A second ventilation area is formed on the insulating protective member and is arranged opposite to the first ventilation area. The second ventilation area is provided with a second through hole, and the radial dimension of the second through hole is d2, in mm; the radial dimension of the first through hole is d1, in mm; 1.2≤d2 / d1≤2.

6. The battery cell according to claim 5, characterized in that The insulating protective member is further provided with an auxiliary exhaust area, and the auxiliary exhaust area is provided with auxiliary ventilation holes.

7. The battery cell according to claim 1, characterized in that There are multiple convex parts, and the multiple convex parts are arranged at intervals around the exhaust hole. Two adjacent convex parts, the support member and the first cover plate form an exhaust channel, and at least part of the gas flows to the exhaust hole through the exhaust channel.

8. The battery cell according to claim 1, characterized in that The support member is a metal member; And / or, the support member is arranged at one end of the protrusion facing the interior of the battery cell.

9. The battery cell according to claim 1, characterized in that: Also includes: a second cover plate connected to the housing, wherein a mounting hole is formed on the second cover plate; The pole is arranged in the mounting hole, and the pole includes a positive pole and a negative pole.

10. A battery pack, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 9.

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