Cover plate assembly and battery cell

Abstract

A cover plate assembly and a battery cell comprising the cover plate assembly. The cover plate assembly comprises a cover plate (1) and an explosion-proof valve body (2). The explosion-proof valve body (2) comprises a valve plate (20); the valve plate (20) comprises an opening portion (200) and an outer edge portion (201) surrounding the opening portion (200); the outer edge portion (201) is connected to the cover plate (1); the valve plate (20) is provided with a score line (202); the score line (202) has a first end (2020) and a second end (2021); a base (21) surrounds the outer edge portion (201); and the base (21) has a first side surface (210) and a second side surface (211). The residual thickness of the valve plate (20) at the score line (202) is T, the depth of the score line is T1, the distance between the first side surface (210) and the second side surface (211) is W1, and the minimum distance between the score line (202) and the second side surface (211) is W2, satisfying: 0.2≤T / (T+T1)≤0.5, and 0.3≤W2-W1≤5. By optimizing the parameters and dimensions of portions of the valve plate (20), it is ensured that the explosion-proof valve body (2) and the cover plate (1) have sufficient structural strength, thereby improving the overall strength of the battery cell. In addition, when the pressure inside the battery cell reaches a threshold, the opening portion (200) can be opened in a timely manner by means of the score line (202), thereby improving the safety of a battery.

Description

Cover plate assembly and single battery

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number CN202410101132.7, entitled “A cover assembly and single cell battery,” filed with the Patent Office of China on January 25, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present application belongs to the field of battery technology, and specifically relates to a cover plate assembly and a single battery. Background Art

[0004] At present, with the development of the application of lithium batteries in the automotive power industry, higher requirements are placed on the strength and safety performance of batteries. Existing single-cell batteries often adopt the design of safety explosion-proof valves. When a single-cell battery has a fault such as thermal runaway, the air pressure inside the single-cell battery reaches the preset value. The explosion-proof valve will open and discharge the high-pressure gas inside the single-cell battery in time to avoid more serious safety problems in the single-cell battery.

[0005] However, the explosion-proof valve structure also affects the structural strength of the entire single battery. If the explosion-proof valve structure is insufficiently strong and has poor stability, it is easy to open prematurely or completely break, thereby causing damage to the entire battery and battery pack. If the explosion-proof valve structure is too strong, it is easy for the explosion-proof valve to fail to open in time.

[0006] Application Contents

[0007] In view of this, the present application proposes a cover assembly to solve the above technical problems.

[0008] In a first aspect, the present application provides a cover plate assembly, comprising:

[0009] A cover plate, wherein the cover plate is provided with an explosion-proof hole;

[0010] The explosion-proof valve body is connected to the cover plate and covers the explosion-proof hole. The explosion-proof valve body includes:

[0011] a valve disc, the valve disc comprising an opening portion and an outer edge portion surrounding the opening portion, the outer edge portion being connected to the cover plate, the valve disc being provided with a notch, the notch being provided between the opening portion and the outer edge portion and partially surrounding the opening portion, the notch having corresponding first and second ends in a direction surrounding the opening portion;

[0012] a base, the base surrounding the outer edge portion, the outer edge portion being connected to the cover plate through the base, the base having a first side surface connected to the outer edge portion and a second side surface facing away from the outer edge portion;

[0013] The residual thickness of the valve plate at the notch is T, the depth of the notch is T1, the first side and the second side have a spacing of W1, the minimum distance between the notch and the second side is W2, and the following conditions are satisfied: 0.2≤T / (T+T1)≤0.5, 0.3≤W2-W1≤5.

[0014] Beneficial effects: Through the parameter size design of the explosion-proof valve body and the notch, it is ensured that the ratio of the residual thickness of the valve plate at the notch to the valve plate thickness is within an optimal range, and at the same time, a better distance is reserved between the notch and the base, ensuring that the explosion-proof valve body and the cover plate have sufficient structural strength to improve the overall strength of the single cell, and at the same time ensuring that the opening part can be opened in time through the notch when the internal pressure of the battery reaches the threshold, thereby improving the safety performance of the battery.

[0015] In an optional embodiment, the following conditions are satisfied: 1.5 mm ≤ W1 ≤ 10 mm;

[0016] And / or, meet the following requirements: 2mm≤W2≤15mm;

[0017] And / or, meet the following requirements: 0.1mm≤T+T1≤0.45mm;

[0018] And / or, satisfying: 0.03mm≤T≤0.1mm.

[0019] In an optional embodiment, the notch has a first straight segment, a first arc segment, a second straight segment, a second arc segment, and a third straight segment connected in sequence, the first straight segment, the second straight segment, and the third straight segment all extend parallel to the first direction, and the first straight segment and the third straight segment are respectively spaced apart from the second straight segment in the second direction, an end of the first straight segment away from the first arc segment is the first end, an end of the third straight segment away from the second arc segment is the second end, an end of the first straight segment away from the third straight segment is the third end, and an end of the third straight segment away from the first straight segment is the fourth end, and the first direction and the second direction intersect;

[0020] The minimum distance between the first end and the second end in the direction in which the notch extends is L, and the minimum distance between the third end and the fourth end in the direction in which the notch extends is L1, satisfying the following: 0.2≤L / L1≤0.8.

[0021] In an optional embodiment, the minimum distances between the first straight line segment, the first arc segment, the second straight line segment, the second arc segment, and the third straight line segment and the outer edge portion facing away from the opening portion are all equal.

[0022] In an optional embodiment, the following conditions are met: 5 mm ≤ L ≤ 40 mm;

[0023] And / or, satisfying: 10mm≤L1≤50mm.

[0024] In an optional embodiment, the valve plate protrudes toward the outside of the explosion-proof hole, and the valve plate has a first cross-section and a second cross-section that are perpendicular to each other, and the first cross-section and the second cross-section are both arc-shaped sections.

[0025] In an optional embodiment, the arc radius of the first cross section is R1, which satisfies: 10 mm ≤ R1 ≤ 50 mm or 150 mm ≤ R1 ≤ 500 mm;

[0026] And / or, the arc radius of the second cross section is R2, which satisfies: 10mm≤R2≤30mm or 150mm≤R2≤500mm.

[0027] In an optional embodiment, the base has a thickness H1 that satisfies: 0.55 mm ≤ H1 ≤ 1.2 mm.

[0028] In an optional embodiment, the thickness of the valve plate between the first end and the second end is H2, which satisfies 0.08 mm ≤ H2 ≤ 0.4 mm.

[0029] In a second aspect, the present application further provides a single cell, comprising the above-mentioned cover plate assembly, wherein the length of the single cell in the first direction is a, satisfying: 50 mm ≤ a ≤ 250 mm;

[0030] The length of the single battery in the second direction is b, which satisfies the following conditions: 10 mm ≤ b ≤ 100 mm;

[0031] The length of the single battery in the third direction is c, which satisfies: 100mm≤c≤600mm or 600mm≤c≤1500mm;

[0032] The first direction, the second direction, and the third direction intersect with each other.

[0033] Beneficial effects: The single cell uses the above-mentioned cover plate assembly, so it has all the beneficial effects of the cover plate assembly, which will not be described here. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0035] FIG1 is a schematic structural diagram of a cover plate assembly according to an embodiment of the present application;

[0036] FIG2 is a partial cross-sectional view of a cover plate assembly according to an embodiment of the present application;

[0037] FIG3 is a schematic structural diagram of an explosion-proof valve body according to an embodiment of the present application;

[0038] FIG4 is a schematic diagram of the structure of the notch of the explosion-proof valve body according to an embodiment of the present application;

[0039] FIG5 is a schematic cross-sectional view of the structure along line AA in FIG4 ;

[0040] FIG6 is an enlarged structural view of portion C in FIG5 ;

[0041] FIG7 is a schematic cross-sectional view of the structure along line BB in FIG5 ;

[0042] FIG8 is a schematic structural diagram of a single cell according to an embodiment of the present application;

[0043] FIG9 is a partial cross-sectional view of a cover plate assembly according to another embodiment of the present application;

[0044] FIG10 is a schematic diagram of a shell rupture of a single cell battery experiment according to an embodiment of the present application;

[0045] Figure numerals: 1. Cover plate; 10. Explosion-proof hole; 2. Explosion-proof valve body; 20. Valve plate; 200. Opening portion; 201. Outer edge portion; 202. Notch; 2020. First end; 2021. Second end; 2022. First straight segment; 2023. First arc segment; 2024. Second straight segment; 2025. Second arc segment; 2026. Third straight segment; 2027. Third end; 2028. Fourth end; 203. First cross section; 204. Second cross section; 21. Base; 210. First side surface; 211. Second side surface; 3. Single cell; 30. Rupture opening; X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0046] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0047] The applicant noted that, at present, with the development of the application of lithium batteries in the automotive power industry, higher requirements are placed on the strength and safety performance of batteries. Existing single cells often adopt the design of safety explosion-proof valves. When a single cell has a fault such as thermal runaway, the air pressure inside the single cell reaches a preset value, and the explosion-proof valve will open and discharge the high-pressure gas inside the single cell in time to avoid more serious safety problems in the single cell.

[0048] However, the explosion-proof valve structure also affects the structural strength of the entire single battery. If the explosion-proof valve structure is insufficiently strong and has poor stability, it is easy to open prematurely or completely break, thereby causing damage to the entire battery and battery pack. If the explosion-proof valve structure is too strong, it is easy for the explosion-proof valve to fail to open in time.

[0049] In view of this, in combination with Figures 1 to 10, an embodiment of the present application provides a cover assembly, which aims to overcome at least one of the above-mentioned technical problems.

[0050] In the following embodiments, a first direction X, a second direction Y, and a third direction Z intersecting each other are introduced, wherein the first direction X is parallel to the length direction of the cover assembly, the second direction Y is parallel to the width direction of the cover assembly, and the third direction Z is parallel to the thickness direction of the cover assembly.

[0051] 1 to 7 , a cover plate assembly includes a cover plate 1 and an explosion-proof valve body 2 .

[0052] The cover plate 1 is provided with an explosion-proof hole 10 , and the explosion-proof valve body 2 is connected to the cover plate 1 and covers the explosion-proof hole 10 . The explosion-proof valve body 2 includes a valve plate 20 and a base 21 .

[0053] The valve plate 20 includes an opening portion 200 and an outer edge portion 201 surrounding the opening portion 200. The outer edge portion 201 is connected to the cover plate 1. The valve plate 20 is provided with a notch 202. The notch 202 is provided between the opening portion 200 and the outer edge portion 201 and partially surrounds the opening portion 200. The notch 202 has a corresponding first end 2020 and a second end 2021 in the direction surrounding the opening portion 200.

[0054] The base 21 surrounds the outer edge 201, and the outer edge 201 is connected to the cover plate 1 through the base 21. The base 21 has a first side surface 210 connected to the outer edge 201 and a second side surface 211 away from the outer edge 201; the residual thickness of the valve plate 20 at the notch 202 is T, the depth of the notch 202 is T1, the first side surface 210 and the second side surface 211 have a spacing W1, and the minimum distance between the notch 202 and the second side surface 211 is W2, satisfying: 0.2≤T / (T+T1)≤0.5, 0.3≤W2-W1≤5.

[0055] By designing the parameters and dimensions of the explosion-proof valve body 2 and the notch 202, it is ensured that the ratio of the residual thickness of the valve plate 20 at the notch 202 to the thickness of the valve plate 20 is within an optimal range, and at the same time, it is ensured that a better distance is reserved between the notch 202 and the base 21, so that the explosion-proof valve body 2 and the cover plate 1 have sufficient structural strength to improve the overall strength of the single cell 3, and at the same time, it is ensured that the opening part 200 can be opened in time through the notch 202 when the internal pressure of the battery reaches the threshold, thereby improving the safety performance of the battery.

[0056] Here, T / (T+T1) can be any one of 0.2, 0.3, 0.4, and 0.5, or a range of any two of them.

[0057] At the same time, W2-W1 can be any one of 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5, or a range of any two of them.

[0058] Furthermore, in some embodiments, the following is satisfied: 1.5 mm ≤ W1 ≤ 10 mm; it is understandable that W1 can be 1.5 mm or 10 mm or any value between 1.5 mm and 10 mm.

[0059] Meanwhile, in some embodiments, the following is satisfied: 2 mm ≤ W2 ≤ 15 mm. Similarly, W2 can be 2 mm or 15 mm or any value between 2 mm and 15 mm.

[0060] Meanwhile, in some embodiments, the following is satisfied: 0.1 mm ≤ T+T1 ≤ 0.45 mm; T+T1 can be 0.1 mm or 0.45 mm or any value between 0.1 mm and 0.45 mm.

[0061] Meanwhile, in some embodiments, the following is satisfied: 0.03 mm ≤ T ≤ 0.1 mm. T can be 0.03 mm, 0.1 mm, or any value between 0.03 mm and 0.1 mm.

[0062] In some embodiments, referring to Figures 1 to 4, the notch 202 has a first straight segment 2022, a first arc segment 2023, a second straight segment 2024, a second arc segment 2025 and a third straight segment 2026 connected in sequence, the first straight segment 2022, the second straight segment 2024 and the third straight segment 2026 all extend parallel to the first direction X, and the first straight segment 2022 and the third straight segment 2026 are respectively spaced apart from the second straight segment 2024 in the second direction Y.

[0063] In this embodiment, the first straight line segment 2022 and the third straight line segment 2026 are collinear, the end of the first straight line segment 2022 away from the first arc segment 2023 is the first end 2020, the end of the third straight line segment 2026 away from the second arc segment 2025 is the second end 2021, the end of the first straight line segment 2022 away from the third straight line segment 2026 is the third end 2027, and the end of the third straight line segment 2026 away from the first straight line segment 2022 is the fourth end 2028.

[0064] The minimum distance between the first end 2020 and the second end 2021 in the extending direction of the notch 202 is L, and the minimum distance between the third end 2027 and the fourth end 2028 in the extending direction of the notch 202 is L1, satisfying: 0.2≤L / L1≤0.8.

[0065] L / L1 can be any one of 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8, or a range of any two of them.

[0066] Furthermore, in this embodiment, the minimum distances between the first straight segment 2022 , the first arc segment 2023 , the second straight segment 2024 , the second arc segment 2025 , and the third straight segment 2026 and the side of the outer edge portion 201 away from the opening portion 200 are all equal.

[0067] It can be understood that, as shown in Figure 4, in this embodiment, the projection of the overall explosion-proof valve body 2 on the plane where the first direction X and the second direction Y are located is a rounded rectangle, and the projection of the opening portion 200 surrounded by the outline in the extension direction of the notch 202 on the plane where the first direction X and the second direction Y are located is also a rounded rectangle similar to the explosion-proof valve body 2, and is located at the center of the explosion-proof valve body 2.

[0068] In some embodiments, the following is satisfied: 5mm≤L≤40mm; L can be a range value of any one of 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, and 40mm, or any two of them.

[0069] In some embodiments, the following is satisfied: 10 mm ≤ L1 ≤ 50 mm.

[0070] L1 can be any one of 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, 40mm, 41mm, 42mm, 43mm, 44mm, 45mm, 46mm, 47mm, 48mm, 49mm, and 50mm, or a range value consisting of any two of them.

[0071] 4 , 5 and 7 , the valve disc 20 protrudes toward the outside of the explosion-proof hole 10 , and the valve disc 20 has a first cross section 203 and a second cross section 204 perpendicular to each other, both of which are arc-shaped cross sections.

[0072] It can be understood that the first cross section 203 is the cross section of the valve disc 20 along line AA in FIG. 4 and FIG. 5 , and the second cross section 204 is the cross section of the valve disc 20 along line BB in FIG. 4 and FIG. 7 .

[0073] Further, in some embodiments, referring to FIG5 , the arc radius of the first cross section 203 is R1, satisfying: 10 mm ≤ R1 ≤ 50 mm or 150 mm ≤ R1 ≤ 500 mm; it is understandable that R1 can be 10 mm or 50 mm or 150 mm or 500 mm or any value between 10 mm and 50 mm or any value between 150 mm and 500 mm.

[0074] In some embodiments, referring to FIG. 7 , the arc radius of the second cross section 204 is R2, which satisfies: 10 mm ≤ R2 ≤ 30 mm or 150 mm ≤ R2 ≤ 500 mm.

[0075] It is understandable that R2 can be 10 mm or 30 mm or 150 mm or 500 mm or any value between 10 mm and 30 mm or any value between 150 mm and 500 mm.

[0076] In addition, in order to improve the welding strength between the base 21 and the cover plate 1 and improve the structural strength of the entire explosion-proof valve body 2 and the cover plate 1, in some embodiments, the base 21 has a thickness H1 that satisfies: 0.55 mm ≤ H1 ≤ 1.2 mm.

[0077] H1 can be 0.5mm, 0.51mm, 0.52mm, 0.53mm, 0.54mm, 0.55mm, 0.56mm, 0.57mm, 0.58mm, 0.59mm, 0.6mm, 0.61mm, 0.62mm, 0.63mm, 0.64mm, 0.65mm, 0.66mm, 0.67mm, 0.68mm, 0.69mm, 0.7mm, 0.71mm, 0.72mm, 0.73mm, 0.74mm, 0.75mm, 0.76mm, 0.77mm, 0.78mm, 0.79mm, 0.8mm, 0.81mm, 0.82mm, 0.83mm, 0.84mm, 0.85mm, 0. The range value consists of any one of 86mm, 0.87mm, 0.88mm, 0.89mm, 0.9mm, 0.91mm, 0.92mm, 0.93mm, 0.94mm, 0.95mm, 0.96mm, 0.97mm, 0.98mm, 0.99mm, 1mm, 1.01mm, 1.02mm, 1.03mm, 1.04mm, 1.05mm, 1.06mm, 1.07mm, 1.08mm, 1.09mm, 1.1mm, 1.11mm, 1.12mm, 1.13mm, 1.14mm, 1.15mm, 1.16mm, 1.17mm, 1.18mm, 1.19mm, and 1.2mm, or any two of them.

[0078] In addition, the weight of the valve plate 20 is further reduced on the basis of ensuring the structural strength of the overall explosion-proof valve body 2. In some embodiments, the thickness of the valve plate 20 between the first end 2020 and the second end 2021 is H2, satisfying 0.08mm≤H2≤0.4mm.

[0079] H2 can be any one of 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, 0.15mm, 0.16mm, 0.17mm, 0.18mm, 0.19mm, 0.2mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.3mm, 0.31mm, 0.32mm, 0.33mm, 0.34mm, 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, and 0.4mm, or a range value consisting of any two of them.

[0080] In addition, referring to FIG. 2 , illustratively, in this embodiment, the integral explosion-proof valve body 2 is located in the explosion-proof hole 10 , and the explosion-proof valve body 2 is disposed close to the bottom of the cover plate 1 .

[0081] In some embodiments, referring to FIG. 9 , for example, the integral explosion-proof valve body 2 may also be disposed near the top of the cover plate 1 . In addition, in other embodiments, the position of the explosion-proof valve body 2 may be flexibly adjusted within the explosion-proof hole 10 .

[0082] Below, the embodiment of the present application provides parameter experiments to verify the technical effects of the parameter value range of the present application:

[0083] Table 1:

[0084] Table 2:

[0085] Among them, ① comparing Example 1 and Comparative Example 1, the T and T+T1 values ​​of the two cover plates 1 are different, and the other dimensions are the same, so T / T+T1 is different. The residual thickness of the valve plate 20 of Comparative Example 1 is too small, and the opening portion 200 ruptures and fails during the test. The opening portion 200 opens prematurely, and there is a safety hazard during the use of the battery cell. During the test process of Example 1, the opening portion 200 opens normally, and the battery shell does not rupture or fail, and the thermal runaway test is passed.

[0086] ② Comparing Example 2 and Comparative Example 2, the L values ​​of the two cover plates 1 are different, and the other dimensions are the same. The L length of Comparative Example 2 is too long, and the ratio of L / L1 is too large. During the test, the opening time of the opening portion 200 is delayed. Referring to Figure 10, the battery shell has ruptured and failed, and a rupture opening 30 has been formed, but the opening portion 200 has not yet opened, and cannot provide safety protection for the battery during use. During the test process of Example 2, the opening portion 200 opened normally, and the battery shell did not rupture or fail, and the thermal runaway test passed.

[0087] ③ Comparing Example 3 and Comparative Example 3, the L values ​​of the two cover plates 1 are different, and the other dimensions are the same. The L length of Comparative Example 3 is too small, and the ratio of L / L1 is too small. During the test, the opening portion 200 is opened prematurely. Although the battery shell does not rupture or fail, the premature opening of the opening portion 200 cannot provide safety protection for the battery during use. During the test process of Example 3, the opening portion 200 is opened normally, and the battery shell does not rupture or fail, and the thermal runaway test is passed.

[0088] ④ Comparing Example 4 and Comparative Example 4, the W2 values ​​of the two cover plates 1 are different, and the other dimensions are the same. The value of W2-W1 of Comparative Example 4 is too small, and the opening portion 200 of the valve plate 20 is broken during the welding process, resulting in failure of the test. This is because the notch 202 is too close to the edge of the valve plate 20, causing the notch 202 to be affected by the heat of welding, thereby causing the opening portion 200 to deform and break. During the test process of Example 4, the opening portion 200 opened normally, and the battery shell did not suffer any rupture or failure, and the thermal runaway test passed.

[0089] ⑤ Comparing Example 5 and Comparative Example 5, the T values ​​of the two cover plates 1 are different, and the other dimensions are the same. The T value of Comparative Example 5 is too large, and the opening time of the opening portion 200 is delayed during the test. Referring to Figure 10, the battery shell has ruptured and failed, and an exemplary rupture opening 30 has been formed, but the opening portion 200 has not yet opened, and cannot provide safety protection for the battery during use. During the test process of Example 5, the opening portion 200 opened normally, and the battery shell did not rupture or fail, and the thermal runaway test passed.

[0090] ⑥ Comparing Example 6 and Comparative Example 6, the W2 values ​​of the two cover plates 1 are different, and the other dimensions are the same. The value of W2-W1 in Comparative Example 6 is too small, which affects the normal opening of the opening portion 200, resulting in failure of the explosion-proof valve body 2 during the test. Referring to Figure 10, the battery shell has ruptured and failed, and a rupture opening 30 has been formed, but the opening portion 200 has not yet opened, and cannot play a role in protecting the battery during use. During the test of Example 5, the opening portion 200 opened normally, and the battery shell did not rupture or fail, and the thermal runaway test passed.

[0091] ⑦ Comparing Example 7 and Comparative Example 7, the L1 values ​​of the two cover plates 1 are different, and the other dimensions are the same. The ratio of L / L1 of Comparative Example 7 is too large, and the opening time of the opening portion 200 is delayed during the test. Referring to Figure 10, the battery shell has ruptured and failed, and a rupture opening 30 has been formed, but the valve plate 20 has not yet opened, and cannot provide safety protection for the battery during use. However, during the test of Example 7, the opening portion 200 opened normally, and the battery shell did not rupture or fail, and the thermal runaway test passed.

[0092] Accordingly, the embodiment of the present application provides a single cell 3, which includes the above-mentioned cover plate assembly. It is understandable that the single cell 3 can have all the technical features and corresponding beneficial effects of the above-mentioned cover plate assembly, which will not be repeated here.

[0093] In some embodiments, referring to FIG. 7 , the length of the single cell 3 in the first direction X is a, satisfying: 50 mm ≤ a ≤ 250 mm; the length of the single cell 3 in the second direction Y is b, satisfying: 10 mm ≤ b ≤ 100 mm; the length of the single cell 3 in the third direction Z is c, satisfying: 100 mm ≤ c ≤ 600 mm or 600 mm ≤ c ≤ 1500 mm.

[0094] It will be appreciated that a may be 50 mm or 250 mm or any value between 50 mm and 250 mm, similarly, b may be 10 mm or 100 mm or any value between 10 mm and 100 mm, and c may be 100 mm or 600 mm or 1500 mm or any value between 100 mm and 600 mm or any value between 600 mm and 1500 mm.

[0095] The above is a detailed introduction to a cover plate assembly and a single cell provided in the embodiments of the present application, and specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and core idea of ​​the present application; ordinary technicians in this field should understand that: they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solution of the embodiments of the present application. Industrial Applicability

[0096] The cover plate is provided with an explosion-proof hole; the explosion-proof valve body is connected to the cover plate and seals the explosion-proof hole, the explosion-proof valve body includes a valve plate and a base, the valve plate includes an opening portion and an outer edge portion surrounding the opening portion, the outer edge portion is connected to the cover plate, the valve plate is provided with a notch, the notch is provided between the opening portion and the outer edge portion and partially surrounds the opening portion, the notch has corresponding first and second ends in the direction surrounding the opening portion; the base surrounds the outer edge portion, the outer edge portion is connected to the cover plate through the base, the base has a first side surface connected to the outer edge portion and a second side surface facing away from the outer edge portion; the residual thickness of the valve plate at the notch is T, the depth of the notch is T1, the first side surface and the second side surface have a spacing W1, the minimum distance between the notch and the second side surface is W2, satisfying: 0.2≤T / (T+T1)≤0.5, 0.3≤W2-W1≤5. By designing the parameters and dimensions of the explosion-proof valve body and the various parts of the notch, it is ensured that the ratio of the residual thickness of the valve plate at the notch to the valve plate thickness is within an optimal range, and at the same time, a better distance is reserved between the notch and the base. It is ensured that the explosion-proof valve body and the cover plate have sufficient structural strength to improve the overall strength of the single cell, and at the same time, it is ensured that the opening part can be opened in time through the notch when the internal pressure of the battery reaches the threshold, thereby improving the safety of the battery.

Claims

1. A cover plate assembly, characterized in that, Comprising: A cover plate, an explosion-proof hole is provided on the cover plate; An explosion-proof valve body, the explosion-proof valve body is connected to the cover plate and seals the explosion-proof hole, the explosion-proof valve body includes: A valve disc, the valve disc includes an opening part and an outer edge part surrounding the opening part, the outer edge part is connected to the cover plate, the valve disc is provided with a notch, the notch is arranged between the opening part and the outer edge part and partially surrounds the opening part, the notch has a corresponding first end and a second end in the direction of surrounding the opening part; A base, the base surrounds the outer edge part, and the outer edge part is connected to the cover plate through the base, the base has a first side surface connecting the outer edge part and a second side surface facing away from the outer edge part; Wherein, the residual thickness of the valve disc at the notch is T, the depth of the notch is T1, the distance between the first side surface and the second side surface is W1, and the minimum distance between the notch and the second side surface is W2, satisfying: 0.2≤T / (T + T1)≤0.5, 0.3≤W2 - W1≤5.

2. The cover plate assembly according to claim 1, wherein Satisfying: 1.5mm≤W1≤10mm; and / or, satisfying: 2mm≤W2≤15mm; and / or, satisfying: 0.1mm≤T + T1≤0.45mm; and / or, satisfying: 0.03mm≤T≤0.1mm.

3. The cover plate assembly according to claim 1, wherein The notch has a first straight line segment, a first arc segment, a second straight line segment, a second arc segment and a third straight line segment connected in sequence, the first straight line segment, the second straight line segment and the third straight line segment all extend parallel to the first direction, and the first straight line segment and the third straight line segment are respectively spaced from the second straight line segment in the second direction, one end of the first straight line segment away from the first arc segment is the first end, one end of the third straight line segment away from the second arc segment is the second end, one end of the first straight line segment away from the third straight line segment is the third end, one end of the third straight line segment away from the first straight line segment is the fourth end, the first direction and the second direction intersect; the minimum distance between the first end and the second end in the extending direction of the notch is L, and the minimum distance between the third end and the fourth end in the extending direction of the notch is L1, satisfying: 0.2≤L / L1≤0.

8.

4. The cover plate assembly according to claim 3, wherein The minimum distances between the first straight line segment, the first arc segment, the second straight line segment, the second arc segment and the third straight line segment and the side of the outer edge part facing away from the opening part are all equal.

5. The cover plate assembly according to claim 3, characterized in that, Satisfying: 5mm≤L≤40mm; and / or, satisfying: 10mm≤L1≤50mm.

6. The cover plate assembly according to claim 1, wherein The valve disc bulges towards the outside of the explosion-proof hole, the valve disc has a first cross-section and a second cross-section perpendicular to each other, and both the first cross-section and the second cross-section are arc-shaped cross-sections.

7. The cover plate assembly according to claim 6, characterized in that, The arc radius of the first cross-section is R1, satisfying: 10mm≤R1≤50mm or 150mm≤R1≤500mm; and / or, the arc radius of the second cross-section is R2, satisfying: 10mm≤R2≤30mm or 150mm≤R2≤500mm.

8. The cover plate assembly according to claim 1, characterized in that, The base has a thickness H1, satisfying: 0.55mm≤H1≤1.2mm.

9. The cover plate assembly according to claim 4, wherein The thickness H2 of the valve sheet between the first end and the second end satisfies 0.08 mm ≤ H2 ≤ 0.4 mm.

10. A single cell, characterized in that, Comprising: The cover plate assembly according to any one of claims 1 to 9, wherein the length of the single cell in the first direction is a, satisfying 50 mm ≤ a ≤ 250 mm; the length of the single cell in the second direction is b, satisfying 10 mm ≤ b ≤ 100 mm; the length of the single cell in the third direction is c, satisfying 100 mm ≤ c ≤ 600 mm or 600 mm ≤ c ≤ 1500 mm; the first direction, the second direction and the third direction intersect pairwise.

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