Battery monomer, battery pack and electric equipment

Abstract

This application discloses a battery cell, a battery pack, and electrical equipment, belonging to the field of battery technology. The battery cell includes: a housing with a receiving cavity; an electrode assembly disposed in the receiving cavity; a bottom wall of the housing having a first surface facing the electrode assembly and a second surface away from the electrode assembly, and a pressure relief port penetrating the first and second surfaces; an explosion-proof valve connected to and sealing the pressure relief port; a first protective film disposed in the receiving cavity, its orthographic projection along the thickness direction covering the pressure relief port on the first surface; a first connecting member located between the first protective film and the first surface, connected to both the first protective film and the first surface respectively; the orthographic projection area of ​​the first connecting member along the thickness direction on the first surface is S1, the orthographic projection area of ​​the first protective film along the thickness direction on the first surface is S2, and the area of ​​the pressure relief port on the first surface is S8; satisfying: 0.4≤(S2-S1) / S8≤1.5. By setting the area relationship, the first protective film is prevented from peeling off from the first surface, thus protecting the explosion-proof valve.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a battery cell, a battery pack, and an electrical device. Background Technology

[0002] In the prior art, the explosion-proof valve is located on the bottom wall of the casing. The electrolyte deposited at the explosion-proof valve will corrode the explosion-proof valve and affect the safety performance of the battery cell. Summary of the Invention

[0003] Purpose of the invention: This application provides a battery cell to solve the problem of corrosion caused by deposits at the explosion-proof valve, which affects the reliability of the battery cell; another purpose of this application is to provide a battery pack including the above-mentioned battery cell; yet another purpose of this application is to provide an electrical device including the above-mentioned battery pack.

[0004] Technical solution: This application provides a single battery cell, comprising:

[0005] The shell has a receiving cavity;

[0006] Electrode assembly, located within the receiving cavity;

[0007] The housing includes a bottom wall having a first surface facing the electrode assembly and a second surface away from the electrode assembly, and the bottom wall having a pressure relief port extending through the first and second surfaces along the thickness direction of the bottom wall;

[0008] Explosion-proof valve, the explosion-proof valve is connected to the orifice wall of the pressure relief port and the pressure relief port is sealed;

[0009] A first protective film and a first connector are provided. The first protective film is disposed in the receiving cavity, and the orthographic projection of the first protective film on the first surface along the thickness direction covers the pressure relief port. The first connector is located between the first protective film and the first surface and is connected to the first protective film and the first surface respectively, so that the first protective film seals the pressure relief port.

[0010] The orthographic projection area of ​​the first connector on the first surface along the thickness direction is S1mm. 2 The orthographic projection area of ​​the first protective film on the first surface along its thickness direction is S2mm. 2 The area of ​​the pressure relief port on the first surface is S8mm. 2 The single battery cell satisfies: 0.4≤(S2-S1) / S8≤1.5.

[0011] In some embodiments, it also includes:

[0012] The second protective film is located outside the receiving cavity, and the second connecting member is located between the second protective film and the second surface and is connected to the second protective film and the second surface respectively, so that the second protective film seals the pressure relief port.

[0013] The projected area of ​​the second connector on the second surface along the thickness direction is S3mm. 2 The projected area of ​​the second protective film on the second surface along the thickness direction is S4mm. 2 The pressure relief port has an area of ​​S9mm on the second surface. 2 The cell size of the battery cell must satisfy the following condition: 0.4 ≤ (S4-S3) / S9 ≤ 1.5.

[0014] In some embodiments, a single battery cell satisfies one or more of the following conditions:

[0015] (a) 242≤S1≤1400;

[0016] (b) 105≤S2≤5000;

[0017] (c) 100≤S8≤2000.

[0018] In some embodiments, a single battery cell satisfies one or more of the following conditions:

[0019] (d) 24≤S3≤1920;

[0020] (e) 120≤S4≤3200;

[0021] (f) 100≤S9≤2000.

[0022] In some embodiments, the orthographic projection of the first protective film on the first surface coincides with the explosion-proof valve; and / or,

[0023] The orthographic projection of the second protective film on the second surface coincides with the explosion-proof valve.

[0024] In some embodiments, the second protective film has a plurality of vent holes that penetrate the second protective film along the thickness direction.

[0025] In some embodiments, a plurality of vent holes are arranged in an array perpendicular to the thickness direction.

[0026] In some embodiments, it also includes:

[0027] A bottom support plate is located between the electrode assembly and the bottom wall, and the bottom support plate is connected to the housing.

[0028] The base plate has clearance holes that penetrate the base plate along the thickness direction and correspond to the position of the pressure relief port. The first protective film is located inside the clearance holes.

[0029] In some embodiments, the orthogonal projected area of ​​the explosion-proof valve on the bottom wall along the thickness direction is S5mm. 2 The area of ​​the first surface is S6mm.2 The area of ​​the second surface is S7mm. 2 A single battery cell must meet one or more of the following conditions:

[0030] (g) 0.01≤S5 / S6≤0.5;

[0031] (h) 0.008≤S5 / S7≤0.5.

[0032] In some embodiments, a single battery cell satisfies one or more of the following conditions:

[0033] (i) 100≤S5≤2800;

[0034] (j) 1000≤S6≤50000;

[0035] (k) 1200≤S7≤70000.

[0036] In some embodiments, the thickness of the first connector along the thickness direction is D1mm, the thickness of the second connector along the thickness direction is D2mm, and the battery cell satisfies one or more of the following conditions:

[0037] (n) 0.01≤D1≤0.1;

[0038] (m) 0.01≤D2≤0.1.

[0039] In some embodiments, the orthographic projection of the first protective film along the thickness direction on the first surface is an ellipse or a polygon, and / or, the orthographic projection of the second protective film along the thickness direction on the second surface is an ellipse or a polygon.

[0040] In some embodiments, it also includes:

[0041] The top cover plate is connected to the housing and seals the receiving cavity, while the bottom wall is positioned opposite to the top cover plate.

[0042] Accordingly, this application also provides a battery pack, including a battery cell as described in any of the above embodiments.

[0043] Accordingly, this application also provides an electrical device including a battery pack as described in the above embodiments.

[0044] Beneficial Effects: Compared with the prior art, the battery cell provided in this application includes: a housing having a receiving cavity; an electrode assembly disposed in the receiving cavity; the housing includes a bottom wall having a first surface facing the electrode assembly and a second surface away from the electrode assembly, the bottom wall having a pressure relief port that penetrates the first and second surfaces along the thickness direction of the bottom wall; an explosion-proof valve connected to the wall of the pressure relief port and sealing the pressure relief port; a first protective film and a first connector, the first protective film being disposed in the receiving cavity, and the orthographic projection of the first protective film along the thickness direction on the first surface covering the pressure relief port; the first connector being located between the first protective film and the first surface and connected to the first protective film and the first surface respectively, so that the first protective film seals the pressure relief port; wherein, the orthographic projection area of ​​the first connector along the thickness direction on the first surface is S1, the orthographic projection area of ​​the first protective film along the thickness direction on the first surface is S2, and the area of ​​the pressure relief port on the first surface is S8; the battery cell satisfies: 0.4≤(S2-S1) / S8≤1.5. This application provides a first protective film and a first connector, with an area ratio between the first connector, the first protective film, and the pressure relief port. This ensures the peel force between the first protective film and the first surface, preventing the first protective film from peeling off the first surface. It also blocks the electrolyte from contacting the explosion-proof valve, preventing the electrolyte from corroding the explosion-proof valve and improving the reliability of the battery cell.

[0045] It is understood that, compared with the prior art, the battery pack provided in this application embodiment includes all the technical features and technical effects of the above-mentioned battery cells, which will not be repeated here.

[0046] It is understood that, compared with the prior art, the electrical device provided in this application embodiment includes all the technical features and technical effects of the above-mentioned battery pack, and will not be repeated here. Attached Figure Description

[0047] The technical solution and other beneficial effects of this application will become apparent from the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0048] Figure 1 An exploded view of a single battery cell provided in an embodiment of this application;

[0049] Figure 2 This is a schematic diagram of the structure of the casing in a battery cell provided in an embodiment of this application;

[0050] Figure 3 for Figure 1 Schematic diagram of the cross section of AA;

[0051] Figure 4 for Figure 3 A magnified view of a portion of region B in the middle;

[0052] Figure 5for Figure 4 A magnified view of a portion of region C in the middle;

[0053] Figure 6 This is a schematic diagram of the structure of the second connector and the second protective film in a battery cell provided in the embodiments of this application;

[0054] Figure 7 This is a schematic diagram of the structure of the explosion-proof valve in a battery cell provided in an embodiment of this application;

[0055] Figure 8 This is a schematic diagram of the structure of the first connector and the first protective film in a battery cell provided in an embodiment of this application.

[0056] Reference numerals: 100-Housing shell; 110-Pressure relief port; 120-Bottom wall; 121-First surface; 122-Second surface; 130-Receiving cavity; 200-Second protective membrane; 210-Second connector; 220-Ventilation hole; 300-Explosion-proof valve; 310-Welded part; 320-Weak part; 330-Reinforcing part; 400-First protective membrane; 410-First connector; 500-Bottom support plate; 510-Allowing hole; 600-Electrode assembly; 700-Connecting piece; 800-Top cover piece; X-Thickness direction. Detailed Implementation

[0057] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0058] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for mutual communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances. In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically limited. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0059] The following disclosure provides many different implementations or examples for carrying out different structures of this application. To simplify the disclosure of this application, the components and arrangements of specific examples are described below. Of course, these are merely examples and are not intended to limit this application.

[0060] This application provides a single battery cell; please refer to [link / reference]. Figure 1 , Figure 2 , Figure 3 and Figure 4 , Figure 1 An exploded view of a single battery cell provided in an embodiment of this application is shown; Figure 2 This illustration shows a structural diagram of the casing in a battery cell provided in an embodiment of this application; Figure 3 It indicated Figure 1 Schematic diagram of the cross section of AA; Figure 4 It indicated Figure 3 A partially enlarged schematic diagram of region B in this application. An embodiment of this application provides a battery cell comprising: a housing 100, an electrode assembly 600, an explosion-proof valve 300, a first protective film 400, and a first connector 410; the housing 100 has a receiving cavity 130; the electrode assembly 600 is disposed in the receiving cavity 130; the housing 100 includes a bottom wall 120, the bottom wall 120 having a first surface 121 facing the electrode assembly 600 and a second surface 122 away from the electrode assembly 600, the bottom wall 120 having a pressure relief port 110, the pressure relief port 110 penetrating the first surface 121 and the second surface 122 along the thickness direction X of the bottom wall 120; the explosion-proof valve 300 is connected to the wall of the pressure relief port 110 and seals the pressure relief port 110; the first protective film 400 is provided with… Within the receiving cavity 130, the orthographic projection of the first protective film 400 along the thickness direction X onto the first surface 121 covers the pressure relief port 110; the first connector 410 is located between the first protective film 400 and the first surface 121 and is connected to the first protective film 400 and the first surface 121 respectively, so that the first protective film 400 seals the pressure relief port 110; wherein, the orthographic projection area of ​​the first connector 410 along the thickness direction X onto the first surface 121 is S1, the orthographic projection area of ​​the first protective film 400 along the thickness direction X onto the first surface 121 is S2, and the area of ​​the pressure relief port 110 on the first surface 121 is S8; the battery cell satisfies: 0.4≤(S2-S1) / S8≤1.5. This application provides a first protective film 400 on the surface of the explosion-proof valve 300 facing the receiving cavity 130, which can prevent the electrolyte from contacting the explosion-proof valve 300 when the battery cell is facing downward or under vibration conditions, causing the explosion-proof valve 300 to be corroded by the electrolyte and affecting the safety performance of the battery cell.

[0061] Please see Figure 8 , Figure 8This illustration shows the structure of the first connector and the first protective film in a battery cell provided in this application embodiment. Furthermore, by setting the first protective film 400 and the first connector 410, and establishing an area ratio between the first connector 410, the first protective film 400, and the pressure relief port 110, the application increases the peel force between the first protective film 400 and the first surface 121, preventing the first protective film 400 from peeling off from the first surface 121, thus preventing electrolyte leakage from corroding the explosion-proof valve 300 and improving the reliability of the battery cell.

[0062] It should be noted that in the embodiments of this application, existing dimensional measuring tools such as vernier calipers and micrometers are used to measure the length and width dimensions of the orthographic projection of the first connector 410 along the thickness direction X on the first surface 121, the length and width dimensions of the orthographic projection of the first protective film 400 along the thickness direction X on the first surface 121, and the length and width dimensions of the pressure relief port 110 on the first surface 121, and then calculate S1, S2, and S8. The value of (S2-S1) / S8 is in the range of 0.4 to 1.5, that is, this value can be any value among 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, and 1.5 or a range between any two values. Without changing the thickness of the first connector 410, the smaller this value, the greater the peel force between the first protective film 400 and the first surface 121. When the value of (S2-S1) / S8 is in the range of 0.4 to 1.5, since this ratio does not exceed 1.5, it can ensure that the first protective film 400 is firmly fixed to the first surface 121 by the first connector 410, ensuring that the first protective film 400 is always located on the side of the explosion-proof valve 300 facing the receiving cavity 130, thus preventing the explosion-proof valve 300 from being corroded by the electrolyte in the receiving cavity 130. At the same time, since this ratio is not less than 0.4, it can prevent the area of ​​the first connector 410 at the position of the explosion-proof valve 300 from being too large. When the explosion-proof valve 300 is opened, the solid and liquid substances that rush out inside it will stick to the first connector 410, hindering the pressure relief rate. The first connector 410 will affect the pressure relief rate of the explosion-proof valve 300, and at the same time increase the difficulty and cost of rework.

[0063] In some embodiments, the battery cell further includes: a second protective film 200 and a second connector 210, wherein the second protective film 200 is disposed outside the receiving cavity 130, and at least a portion of the second protective film 200 is exposed from the pressure relief port 110; the second connector 210 is located between the second protective film 200 and the second surface 122 and is connected to the second protective film 200 and the second surface 122 respectively, so that the second protective film 200 seals the pressure relief port 110; wherein the orthographic projection area of ​​the second connector 210 along the thickness direction X on the second surface 122 is S3, the orthographic projection area of ​​the second protective film 200 along the thickness direction X on the second surface 122 is S4, and the area of ​​the pressure relief port 110 on the second surface 122 is S9; the battery cell satisfies: 0.4≤(S4-S3) / S9≤1.5. Specifically, by providing a second protective film 200 on the outside of the receiving cavity 130, this application can prevent external debris from impacting the explosion-proof valve 300 during the movement of the battery cell, thereby preventing damage to the explosion-proof valve 300, affecting its function, and improving the reliability of the battery cell.

[0064] It should be noted that in the embodiments of this application, existing dimensional measuring tools such as vernier calipers and micrometers are used to measure the length and width dimensions of the orthographic projection of the second connector 210 along the thickness direction X onto the second surface 122, the length and width dimensions of the orthographic projection of the second protective film 200 along the thickness direction X onto the second surface 122, and the length and width dimensions of the pressure relief port 110 on the second surface 122, and then calculate S3, S4, and S9. The value of (S4-S3) / S9 is in the range of 0.4 to 1.5, that is, this value can be any value among 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, and 1.5 or a range between any two values. The smaller this value is, the greater the peel force between the second protective film 200 and the second surface 122.

[0065] When the value of (S4-S3) / S9 is in the range of 0.4 to 1.5, since this ratio does not exceed 1.5, it can ensure that the first protective film 400 is firmly fixed to the first surface 121 by the first connector 410, ensuring that the first protective film is always located on the side of the explosion-proof valve 300 facing the receiving cavity 130. During the movement of the pool unit, external debris will impact the explosion-proof valve 300 and damage it, affecting the function of the explosion-proof valve 300. At the same time, since this ratio is not less than 0.4, it can avoid the area of ​​the first connector at the explosion-proof valve position being too large. When the explosion-proof valve is opened, the solid and liquid substances that rush out inside will stick to the first connector 410, hindering the pressure relief rate. The first connector 410 will affect the pressure relief rate of the explosion-proof valve 300, and at the same time increase the difficulty and cost of rework.

[0066] In some embodiments, the orthographic projection area of ​​the first connector 410 on the first surface 121 along the thickness direction X is S1mm. 2 The first protective film 400 has a projected area of ​​S2mm along the thickness direction X on the first surface 121, satisfying 242≤S1≤1400. 2 The following conditions must be met: 105 ≤ S2 ≤ 5000, and the area of ​​the pressure relief port 110 on the first surface 121 is S8mm. 2 The condition is satisfied that 100≤S8≤2000.

[0067] It should be noted that the value of S1 is in the range of 242 to 1400, that is, the value can be any value among 242, 300, 500, 880, and 1400 or any range between any two values; the value of S2 is in the range of 105 to 5000, that is, the value can be any value among 370, 2200, 3000, 2200, 3000, and 5000 or any range between any two values; and the value of S3 is in the range of 100 to 2000, that is, the value can be any value among 100, 320, 1066, 1154, and 2000 or any range between any two values.

[0068] If S1, S2, and S3 meet the above range, the bonding strength of the first protective film can be guaranteed, reducing the difficulty of rework.

[0069] In some embodiments, the orthogonal projection area of ​​the second connector 210 on the second surface 122 along the thickness direction X is S3mm. 2 The following conditions must be met: 24 ≤ S3 ≤ 1920, and the orthogonal projection area of ​​the second protective film 200 along the thickness direction X on the second surface 122 is S4 mm. 2 The following conditions must be met: 120 ≤ S4 ≤ 3200, and the area of ​​the pressure relief port 110 on the second surface 122 is S9mm. 2 The condition is satisfied that 100≤S9≤2000.

[0070] It should be noted that the value of S3 is in the range of 24 to 1920, that is, the value can be any value or any two values ​​among 24, 107, 150, 200, 372, 400, 611, 651, 967, 1500, and 1920. The value of S4 is in the range of 120 to 3200, that is, the value can be any value or any two values ​​among 120, 500, 1300, 1500, 1600, 1605, 2250, 1600, and 3200. The value of S9 is in the range of 100 to 2000, that is, the value can be any value or any two values ​​among 100, 200, 320, 1066, 1154, and 2000.

[0071] If S3, S4, and S9 meet the above range, the bonding strength of the second protective film can be guaranteed, reducing the difficulty of rework.

[0072] Please see Figure 5 , Figure 5 It indicated Figure 4 A partially enlarged schematic diagram of region C. In some embodiments, the thickness of the first connector 410 along the thickness direction X is D1 mm, the thickness of the second connector 210 along the thickness direction X is D2 mm, and the battery cell satisfies: 0.01≤D1≤0.1; and / or, 0.01≤D2≤0.1.

[0073] It should be noted that in the embodiments of this application, existing dimensional measuring tools such as vernier calipers and micrometers are used to measure the thickness of the first connector 410 along the thickness direction X and the thickness of the second connector 210 along the thickness direction X. The value of D1 is in the range of 0.01 to 0.1, that is, this value can be any value among 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.1 or a range between any two values. The value of D2 is in the range of 0.01 to 0.1, that is, this value can be any value among 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, and 0.1 or a range between any two values. Controlling the values ​​of D1 and D2 within the above range can ensure the bonding strength while avoiding waste and increased costs.

[0074] It should be noted that the thickness of the first connector 410 and the second connector 210 can be the same. In one embodiment, the thickness of the first connector 410 and the second connector 210 can both be 0.05mm.

[0075] It should be noted that the first connector 410 and the second connector 210 are adhesive layers. The first connector 410 and the second connector 210 can use 3M467 adhesive, a double-sided tape from the 3M brand, or other domestic adhesives or double-sided tapes.

[0076] In some embodiments, the orthographic projection of the first protective film 400 on the first surface 121 exactly covers the explosion-proof valve 300; and / or, the orthographic projection of the second protective film 200 on the second surface 122 exactly covers the explosion-proof valve 300. This ensures effective protection of the explosion-proof valve 300 while reducing the amount of the first protective film 400 and the second protective film 200 used, thus lowering costs.

[0077] Please see Figure 6 , Figure 6This illustration shows a schematic diagram of the structure of the second connector and the second protective film in a battery cell provided in an embodiment of this application. In some embodiments, the second protective film 200 has multiple vent holes 220, which penetrate the second protective film 200 along the thickness direction X. When the battery cell is baked at high temperature, since its internal cavity 130 is a sealed space, the second protective film 200 will collapse after baking due to the thermal expansion and contraction of the internal air. Therefore, this embodiment of the application provides vent holes 220 to make the internal and external air pressure of the battery cell consistent, preventing the second protective film 200 from collapsing and losing its protective effect, and improving the safety of the battery cell.

[0078] In some embodiments, a plurality of vent holes 220 are arranged in an array perpendicular to the thickness direction X. Specifically, the array arrangement of a plurality of vent holes 220 can further improve the speed at which the internal and external air pressure of the battery cell remains consistent, further prevent the second protective film 200 from collapsing and losing its protective effect, and improve the safety of the battery cell.

[0079] In some embodiments, the device further includes: a base plate 500 disposed between the electrode assembly 600 and the bottom wall 120, and connected to the housing 100; the base plate 500 has a clearance hole 510 extending through the base plate 500 along the thickness direction X and corresponding to the position of the pressure relief port 110, and a first protective film 400 disposed within the clearance hole 510. Thus, by providing the base plate 500, the electrode assembly 600 is isolated from the bottom wall 120, preventing short circuits in the electrode assembly 600, while the clearance hole 510 ensures the function of the explosion-proof valve 300 in the event of thermal runaway.

[0080] In some embodiments, the orthogonal projected area of ​​the explosion-proof valve 300 along the thickness direction X on the bottom wall 120 is S5mm. 2 The area of ​​the first surface 121 is S6mm. 2 The area of ​​the second surface 122 is S7 mm. 2 The individual battery cells satisfy the following conditions: 0.01 < S5 / S6 ≤ 0.5; and / or, 0.008 < S5 / S7 ≤ 0.5.

[0081] It should be noted that in the embodiments of this application, existing dimensional measuring tools such as vernier calipers and micrometers are used to measure the orthographic projection of the explosion-proof valve 300 along the thickness direction X on the bottom wall 120, as well as the length and width dimensions of the first surface 121 and the second surface 122, and then calculate S5, S6, and S7. The values ​​of S5 / S6 are in the range of 0.01 to 0.5, that is, the value can be any value among 0.01, 0.1, 0.2, 0.3, 0.4, and 0.5 or a range between any two values. The values ​​of S5 / S7 are in the range of 0.008 to 0.5, that is, the value can be any value among 0.008, 0.1, 0.2, 0.3, 0.4, and 0.5 or a range between any two values. This ensures that the explosion-proof valve 300 explodes normally while avoiding excessively high production costs for individual battery cells.

[0082] In some embodiments, the orthographic projection of the first protective film 400 onto the first surface 121 along the thickness direction X is an ellipse or a polygon, and / or, the orthographic projection of the second protective film 200 onto the second surface 122 along the thickness direction X is an ellipse or a polygon. Thus, the elliptical or polygonal orthographic projection shape can more effectively utilize the space of the first surface 121 and the second surface 122, thereby maximizing the coverage of the pressure relief port 110 or the explosion-proof valve 300 and providing more comprehensive protection without wasting space.

[0083] Please see Figure 7 , Figure 7 This illustration shows a schematic diagram of the structure of the explosion-proof valve in a battery cell provided in an embodiment of this application. In some embodiments, the battery cell further includes a top cover plate 800, which is connected to the housing 100 and seals the receiving cavity 130, with the bottom wall 120 facing the top cover plate 800. In this embodiment, the explosion-proof valve 300 includes a welded portion 310, a weak portion 320, and a reinforcing portion 330. The welded portion 310 is welded to the top cover plate 800 to seal the pressure relief port 110, and the weak portion 320 is disposed between the welded portion 310 and the reinforcing portion 330. During use, the positive and negative electrode materials of the electrode assembly 600 will generate gas. When the internal pressure of the battery cell increases due to thermal runaway or other reasons and reaches a predetermined value, the gas and high-temperature foreign matter will enter from the inside and successively break through the first protective film 400, the weak portion 320 of the explosion-proof valve 300, and the second protective film 200, and be ejected in time to achieve the purpose of timely pressure relief, so as to avoid safety risks such as explosion caused by failure to relieve pressure in time. Generally, battery cells in a vehicle are vertical, with the top cover 800 close to the passenger compartment and the bottom wall 120 close to the chassis, near the ground. In this embodiment, the pressure relief port 110 is positioned facing the top cover 800. In the event of thermal runaway, gas and high-temperature foreign objects can be discharged downwards or to the side, preventing them from being sprayed into the passenger compartment and causing injury to personnel.

[0084] The following provides specific embodiments of the battery cells of this application, through which the application will be described in more detail.

[0085] It should be noted that in the following embodiments, the thickness of the first connector 410 and the second connector 210 is the same, which is 0.05mm. Both the first connector 410 and the second connector 210 use 3M467, a double-sided adhesive from the 3M brand.

[0086] The peel force test method is as follows: a sample with a width of 25 mm and a length greater than 175 mm is placed tightly on a steel plate and left for 20 minutes. Then, the steel plate is fixed, the sample is clamped by a fixture, and the sample is peeled off at a speed of 300 mm / min in a 180° direction. The maximum force during the peeling process is recorded as the peel force.

[0087] The test method for determining whether the burst value is normal is as follows: Inflate the battery until the explosion-proof valve 300 ruptures and releases pressure. The pressure at which the explosion-proof valve 300 ruptures and releases pressure is the burst value. If this value is within the normal range for the corresponding volume and model of battery cell, the burst value is considered normal; if it is outside the range, the burst value is considered abnormal.

[0088] Whether the shell 100 is deformed can be confirmed by observation. If there are cracks, misalignments, or deformations on the surface of the shell 100, it can be considered that the shell 100 has been deformed.

[0089] Among them, rework difficulty refers to the operational difficulty and increased cost of rework. If the difficulty is increased, the rework difficulty is considered high. If there is no additional increase in rework difficulty and rework cost, the rework difficulty is considered low.

[0090] Examples 1-9 and Comparative Examples 1-2 are shown in Tables 1-2:

[0091] Table 1

[0092]

[0093] Table 2

[0094]

[0095] As can be seen from Examples 1-9 and Comparative Examples 1-2 above, when the battery cell satisfies 0.4≤(S2-S1) / S8≤1.5, the bonding strength of the first protective film can be guaranteed, and the rework difficulty is low. Conversely, when (S2-S1) / S8 is too small, the bonding area between the first connector and the explosion-proof valve will be too large. During rework, the explosion-proof valve may be damaged, increasing the rework difficulty and cost. When (S2-S1) / S8 is too large, the first protective film is easily peeled off, and the bonding strength of the first protective film is too small.

[0096] As can be seen from Examples 1-9 and Comparative Examples 1-2 above, when the battery cell satisfies 0.4≤(S4-S3) / S9≤1.5, the bonding strength of the second protective film can be guaranteed, and the rework difficulty is low. Conversely, when (S4-S3) / S9 is too small, the bonding area between the first connector and the explosion-proof valve will be too large. During rework, the explosion-proof valve may be damaged, increasing the rework difficulty and cost. When (S4-S3) / S9 is too large, the first protective film is easily peeled off, and the bonding strength of the first protective film is too small.

[0097] As can be seen from Examples 1-9 and Comparative Examples 1-2 above, when the battery cell satisfies 0.01≤S5 / S6≤0.5 and 0.008≤S5 / S7≤0.5, the burst value of the battery cell is normal and the casing will not deform due to insufficient strength. Conversely, if the ratio of S5 / S6 and S5 / S7 is too small, the burst value of the battery cell is abnormal, the battery cell cannot burst normally, and the casing will deform, increasing the safety risk. If the ratio of S5 / S6 and S5 / S7 is too large, the area of ​​the explosion-proof valve on the bottom wall of the casing will be too large, which will lead to insufficient strength of the casing.

[0098] Accordingly, this application also provides a battery pack, including battery cells as described in any of the above embodiments.

[0099] It is understood that, compared with the prior art, the battery pack provided in this application embodiment includes all the technical features and technical effects of the above-mentioned battery cells, which will not be repeated here.

[0100] Accordingly, this application also provides an electrical device, including a battery pack as described in the above embodiments. The electrical device can be a vehicle, mobile phone, portable device, laptop, ship, spacecraft, electric toy, and power tool, etc. Vehicles can be new energy vehicles, including pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc.; spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.; electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This application does not impose special limitations on the above-described electrical device. It is understood that the electrical device can include all the technical features and beneficial effects of the above-described battery pack, which will not be repeated here.

[0101] The foregoing has provided a detailed description of a single battery, a battery pack, and an electrical device provided in the embodiments of this application. Specific examples have been used in this application to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the technical solutions and core ideas of this application. 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 of the technical features. 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 this application.

Claims

1. A battery cell, characterized in that, include: The housing (100) has a receiving cavity (130); An electrode assembly (600) is disposed in the receiving cavity (130); The top cover plate (800) is connected to the housing (100) and seals the receiving cavity (130). The housing (100) includes a bottom wall (120) disposed toward the top cover plate (800); the bottom wall (120) has a first surface (121) toward the electrode assembly (600) and a second surface (122) away from the electrode assembly (600); the bottom wall (120) has a pressure relief port (110) that extends through the first surface (121) and the second surface (122) along the thickness direction (X) of the bottom wall (120); the pressure relief port (110) is disposed toward the top cover plate (800). An explosion-proof valve (300) is connected to the wall of the pressure relief port (110) and covers the pressure relief port (110). A first protective film (400) and a first connector (410) are provided in the receiving cavity (130), and the orthographic projection of the first protective film (400) on the first surface (121) along the thickness direction (X) covers the pressure relief port (110); the first connector (410) is located between the first protective film (400) and the first surface (121) and is connected to the first protective film (400) and the first surface (121) respectively, so that the first protective film (400) seals the pressure relief port (110). The orthographic projection area of ​​the first connector (410) along the thickness direction (X) on the first surface (121) is S1mm. 2 The orthographic projection area of ​​the first protective film (400) on the first surface (121) along the thickness direction (X) is S2mm. 2 The area of ​​the pressure relief port (110) on the first surface (121) is 8 mm. 2 The battery cell satisfies the following conditions: 0.4≤(S2-S1) / S8≤1.5; 242≤S1≤1400, 105≤S2≤5000, 100≤S8≤2000, in order to increase the peel force between the first protective film (400) and the first surface (121). A second protective film (200) is disposed outside the receiving cavity (130), and at least a portion of the second protective film (200) is exposed from the pressure relief port (110), and the second protective film (200) seals the pressure relief port (110). A base plate (500) is disposed between the electrode assembly (600) and the bottom wall (120), and the base plate (500) is connected to the housing (100); the base plate (500) has a clearance hole (510), the clearance hole (510) penetrates the base plate (500) along the thickness direction (X) and corresponds to the position of the pressure relief port (110), the first protective film (400) is disposed in the clearance hole (510), and the first protective film (400) is spaced apart from the hole wall of the clearance hole (510).

2. The battery cell according to claim 1, characterized in that, Also includes: The second connector (210) is located between the second protective film (200) and the second surface (122) and is connected to the second protective film (200) and the second surface (122) respectively, so that the second protective film (200) seals the pressure relief port (110). The orthographic projection area of ​​the second connector (210) on the second surface (122) along the thickness direction (X) is S3mm. 2 The orthographic projection area of ​​the second protective film (200) on the second surface (122) along the thickness direction (X) is S4mm. 2 The area of ​​the pressure relief port (110) on the second surface (122) is 59 mm. 2 The battery cell satisfies: 0.4≤(S4-S3) / S9≤1.

5.

3. The battery cell according to claim 2, characterized in that, The battery cell satisfies one or more of the following conditions: (d) 24≤S3≤1920; (e) 120≤S4≤3200; (f) 100≤S9≤2000.

4. The battery cell according to claim 1, characterized in that, The orthographic projection of the first protective film (400) onto the first surface (121) coincides with the explosion-proof valve (300); and / or, The orthographic projection of the second protective film (200) onto the second surface (122) coincides with the explosion-proof valve (300).

5. The battery cell according to claim 1, characterized in that, The second protective film (200) has a plurality of vent holes (220) that penetrate the second protective film (200) along the thickness direction (X).

6. The battery cell according to claim 5, characterized in that, The plurality of the vent holes (220) are arranged in an array perpendicular to the thickness direction (X).

7. The battery cell according to claim 1, characterized in that, The orthogonal projection area of ​​the explosion-proof valve (300) on the bottom wall (120) along the thickness direction (X) is S5mm. 2 The area of ​​the first surface (121) is S6 mm. 2 The area of ​​the second surface (122) is S7 mm. 2 The battery cell satisfies one or more of the following conditions: (g) 0.01≤S5 / S6≤0.5; (h) 0.008≤S5 / S7≤0.

5.

8. The battery cell according to claim 7, characterized in that, The battery cell satisfies one or more of the following conditions: (i) 100≤S5≤2800; (j) 1000≤S6≤50000; (k) 1200≤S7≤70000.

9. The battery cell according to claim 2, characterized in that, The thickness of the first connector (410) along the thickness direction (X) is D1mm, the thickness of the second connector (210) along the thickness direction (X) is D2mm, and the battery cell satisfies one or more of the following conditions: (n) 0.01≤D1≤0.1; (m) 0.01≤D2≤0.

1.

10. The battery cell according to claim 1, characterized in that, The first protective film (400) has an orthographic projection along the thickness direction (X) onto the first surface (121) that is elliptical or polygonal, and / or the second protective film (200) has an orthographic projection along the thickness direction (X) onto the second surface (122) that is elliptical or polygonal.

11. The battery cell according to any one of claims 1 to 10, characterized in that, Also includes: A top cover (800) is connected to the housing (100) and seals the receiving cavity (130). The bottom wall (120) is disposed opposite to the top cover (800).

12. A battery pack, characterized in that, Includes the battery cell as described in any one of claims 1 to 11.

13. An electrical appliance, characterized in that, Includes the battery pack as described in claim 12.

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