Battery monomer, battery pack and electric equipment

Abstract

The invention discloses a single battery, a battery pack and electric equipment, and belongs to the technical field of batteries. The electrode assembly is arranged in the accommodating cavity; the bottom wall of the shell is provided with a first surface facing the electrode assembly and a second surface far away from the electrode assembly, and the bottom wall is provided with a pressure relief opening penetrating through the first surface and the second surface; the anti-explosion valve is connected with the hole wall of the pressure relief opening and covers and seals the pressure relief opening; the first protective film is arranged in the containing cavity, and the orthographic projection on the first surface in the thickness direction covers the pressure relief opening. The first connecting piece is located between the first protective film and the first surface and connected with the first protective film and the first surface. The orthographic projection area of the first connecting piece on the first surface in the thickness direction is S1, the orthographic projection area of the first protective film on the first surface in the thickness direction is S2, and the area of the pressure relief opening on the first surface is S8; and (S2-S1) / S8 is greater than or equal to 0.4 and less than or equal to 1.5. The first protective film is prevented from being peeled off from the first surface by setting the area relation, and the anti-explosion valve is protected.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a battery cell, a battery pack and an electrical device. Background Art

[0002] In the prior art, the explosion-proof valve is arranged on the bottom wall of the housing, and the electrolyte deposited on the explosion-proof valve may corrode the explosion-proof valve, thereby affecting the safety performance of the battery cell. Summary of the invention

[0003] Purpose of the invention: The present application provides a battery cell for solving the problem of corrosion of the explosion-proof valve caused by deposition on the explosion-proof valve, thereby affecting the reliability of the battery cell; another purpose of the present application is to provide a battery pack including the above-mentioned battery cell; another purpose of the present application is to provide an electrical device including the above-mentioned battery pack.

[0004] Technical solution: This application provides a battery cell, including: A housing having a receiving cavity; An electrode assembly is arranged in the accommodating cavity; The shell includes a bottom wall, the bottom wall has a first surface facing the electrode assembly and a second surface away from the electrode assembly, the bottom wall has a pressure relief port, and the pressure relief port penetrates the first surface and the second surface along the thickness direction of the bottom wall; An explosion-proof valve, which is connected to the hole wall of the pressure relief port and covers the pressure relief port; a first protective film and a first connecting member, wherein the first protective film is disposed in the accommodating cavity, and an orthographic projection of the first protective film on the first surface along a thickness direction covers the pressure relief port; and the first connecting member is located between the first protective film and the first surface and is respectively connected to the first protective film and the first surface, so that the first protective film seals the pressure relief port; The orthographic projection area of ​​the first connecting member 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 the thickness direction is S2mm 2 , the area of ​​the pressure relief port on the first surface is S8mm 2 ; The battery cell meets the following requirements: 0.4≤(S2-S1) / S8≤1.5.

[0005] In some embodiments, it also includes: a second protective film and a second connecting member, wherein the second protective film is disposed outside the accommodating 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; The orthographic projection area of ​​the second connecting member on the second surface along the thickness direction is S3mm 2 The orthographic projection area of ​​the second protective film on the second surface along the thickness direction is S4mm 2, the area of ​​the pressure relief port on the second surface is S9mm 2 ; The battery cell meets the following requirements: 0.4≤(S4-S3) / S9≤1.5.

[0006] In some embodiments, the battery cell satisfies one or more of the following conditions: (a) 242≤S1≤1400; (b) 105≤S2≤5000; (c) 100≤S8≤2000.

[0007] In some embodiments, the battery cell satisfies one or more of the following conditions: (d) 24≤S3≤1920; (e) 120≤S4≤3200; (f) 100≤S9≤2000.

[0008] In some embodiments, the orthographic projection of the first protective film on the first surface coincides with the explosion-proof valve; and / or, The orthographic projection of the second protective film on the second surface coincides with the explosion-proof valve.

[0009] In some embodiments, the second protective film has a plurality of air holes, and the air holes penetrate the second protective film along the thickness direction.

[0010] In some embodiments, the plurality of air holes are arranged in an array perpendicular to the thickness direction.

[0011] In some embodiments, it also includes: A bottom support plate, which is disposed between the electrode assembly and the bottom wall and is connected to the shell; The bottom support plate has an avoidance hole, which penetrates the bottom support plate along the thickness direction and corresponds to the position of the pressure relief port, and the first protective film is arranged in the avoidance hole.

[0012] In some embodiments, the orthographic projection 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 The battery cell meets one or more of the following conditions: (g) 0.01≤S5 / S6≤0.5; (h) 0.008≤S5 / S7≤0.5.

[0013] In some embodiments, the battery cell satisfies one or more of the following conditions: (i) 100≤S5≤2800; (j) 1000≤S6≤50000; (k) 1200≤S7≤70000.

[0014] In some embodiments, the thickness of the first connector along the thickness direction is D1 mm, the thickness of the second connector along the thickness direction is D2 mm, and the battery cell satisfies one or more of the following conditions: (n) 0.01≤D1≤0.1; (m) 0.01≤D2≤0.1.

[0015] In some embodiments, the orthographic projection of the first protective film on the first surface along the thickness direction is an ellipse or a polygon, and / or the orthographic projection of the second protective film on the second surface along the thickness direction is an ellipse or a polygon.

[0016] In some embodiments, it also includes: A top cover sheet is connected to the shell body and covers the accommodating cavity, and the bottom wall is arranged opposite to the top cover sheet.

[0017] Correspondingly, the present application also provides a battery pack, comprising a battery cell as described in any one of the above embodiments.

[0018] Correspondingly, the present application also provides an electrical device, including the battery pack as described in the above embodiment.

[0019] Beneficial effect: Compared with the prior art, a battery cell provided in an embodiment of the present application comprises: a shell having a containing cavity; an electrode assembly arranged in the containing cavity; the shell comprising a bottom wall, the 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, the pressure relief port penetrating the first surface and the second surface along the thickness direction of the bottom wall; an explosion-proof valve, the explosion-proof valve being connected to the hole wall of the pressure relief port and covering the pressure relief port; a first protective film and a first connecting member, the first protective film being arranged in the containing 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 connecting member 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; wherein the orthographic projection area of ​​the first connecting member on the first surface along the thickness direction is S1, the orthographic projection area of ​​the first protective film on the first surface along the thickness direction 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. The present application provides a first protective film and a first connecting member, and an area ratio relationship is set between the first connecting member, the first protective film and the pressure relief port to ensure the peeling force between the first protective film and the first surface, thereby preventing the first protective film from peeling off from the first surface. This can block the contact between the electrolyte and the explosion-proof valve, prevent the electrolyte from corroding the explosion-proof valve, and improve the reliability of the battery cell.

[0020] It can be understood that, compared with the prior art, the battery pack provided in the embodiment of the present application includes all the technical features and technical effects of the above-mentioned battery cells, which will not be repeated here.

[0021] It can be understood that, compared with the prior art, the electrical equipment provided in the embodiment of the present application includes all the technical features and technical effects of the above-mentioned battery pack, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0023] Figure 1 An exploded view of a battery cell provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of a shell in a battery cell provided in an embodiment of the present application; Figure 3 for Figure 1 Schematic diagram of the cross section of AA; Figure 4 for Figure 3 A partial enlarged schematic diagram of the middle B area; Figure 5 for Figure 4 A partial enlarged schematic diagram of the middle C area; Figure 6 A schematic diagram of the structure of a second connector and a second protective film in a battery cell provided in an embodiment of the present application; Figure 7 A schematic diagram of the structure of an explosion-proof valve in a battery cell provided in an embodiment of the present application; Figure 8 This is a schematic structural diagram of the first connecting member and the first protective film in the battery cell provided in an embodiment of the present application.

[0024] Figure markings: 100-shell; 110-pressure relief port; 120-bottom wall; 121-first surface; 122-second surface; 130-accommodating chamber; 200-second protective film; 210-second connecting piece; 220-air vent; 300-explosion-proof valve; 310-welding portion; 320-weak portion; 330-reinforcement portion; 400-first protective film; 410-first connecting piece; 500-bottom support plate; 510-avoidance hole; 600-electrode assembly; 700-connecting sheet; 800-top cover sheet; X-thickness direction. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0026] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features.

[0027] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application.

[0028] The present application embodiment provides a battery cell. Figure 1 , Figure 2 , Figure 3 and Figure 4 , Figure 1 An exploded view of a battery cell provided in an embodiment of the present application is shown; Figure 2 A schematic diagram of the structure of a shell in a battery cell provided in an embodiment of the present application is illustrated; Figure 3 Indicated Figure 1 Schematic diagram of the cross section of AA; Figure 4 Indicated Figure 3A partial enlarged schematic diagram of the B area in the middle. A battery cell provided in an embodiment of the present application includes: a shell 100, an electrode assembly 600, an explosion-proof valve 300, a first protective film 400 and a first connecting member 410; the shell 100 has a receiving cavity 130; the electrode assembly 600 is arranged in the receiving cavity 130; the shell 100 includes a bottom wall 120, the bottom wall 120 has a first surface 121 facing 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, and the pressure relief port 110 passes through 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 hole wall of the pressure relief port 110 and covers the pressure relief port 110; the first protective film 400 is provided The first protective film 400 is in the accommodating 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 connecting member 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 connecting member 410 on the first surface 121 along the thickness direction X is S1, the orthographic projection area of ​​the first protective film 400 on the first surface 121 along the thickness direction X 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. The present application sets a first protective film 400 on the surface of the explosion-proof valve 300 facing the accommodating cavity 130, which can prevent the electrolyte from contacting the explosion-proof valve 300 when the explosion-proof valve 300 is facing downward or in vibration conditions, causing the explosion-proof valve 300 to be corroded by the electrolyte and affecting the safety performance of the battery cell.

[0029] See also Figure 8 , Figure 8 The schematic diagram of the structure of the first connector and the first protective film in the battery cell provided by the embodiment of the present application is illustrated. Furthermore, the application increases the peeling force between the first protective film 400 and the first connector 410 by setting the first protective film 400 and the first connector 410, and sets an area ratio relationship between the first connector 410, the first protective film 400 and the pressure relief port 110, so as to prevent the first protective film 400 from peeling off from the first surface 121, so that the electrolyte leakage causes corrosion to the explosion-proof valve 300, and improve the reliability of the battery cell.

[0030] It should be noted that in the embodiment of the present application, existing dimension measuring tools such as vernier calipers and micrometers are used to measure the length and width of the orthographic projection of the first connecting member 410 on the first surface 121 along the thickness direction X, the length and width of the orthographic projection of the first protective film 400 on the first surface 121 along the thickness direction X, and the length and width 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, the 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 value between any two values. When the thickness of the first connecting member 410 is not changed, the smaller the value is, the greater the peeling force between the first protective film 400 and the first surface 121 is. When the value of (S2-S1) / S8 is in the range of 0.4~1.5, since the ratio does not exceed 1.5, it can ensure that the first protective film 400 is firmly fixed to the first surface 121 through the first connecting member 410, and ensure that the first protective film 400 is always located on the side of the explosion-proof valve 300 facing the accommodating chamber 130, so as to prevent the explosion-proof valve 300 from being corroded by the electrolyte in the accommodating chamber 130; at the same time, since the ratio is not less than 0.4, it can be avoided that the area of ​​the first connecting member 410 located at the position of the explosion-proof valve 300 is too large. When the explosion-proof valve 300 is opened, the solid and liquid substances rushing out of the explosion-proof valve 300 will adhere to the first connecting member 410, hindering the pressure relief rate. The first connecting member 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.

[0031] In some embodiments, the battery cell further includes: a second protective film 200 and a second connecting member 210, the second protective film 200 is disposed outside the accommodating cavity 130, and at least a portion of the second protective film 200 can be exposed from the pressure relief port 110; the second connecting member 210 is located between the second protective film 200 and the second surface 122 and is respectively connected to the second protective film 200 and the second surface 122, so that the second protective film 200 seals the pressure relief port 110; wherein, the orthographic projection area of ​​the second connecting member 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, the present application provides a second protective film 200 outside the accommodating cavity 130 to prevent external debris from impacting the explosion-proof valve 300 and damaging the explosion-proof valve 300 during the movement of the battery cell, thereby affecting the function of the explosion-proof valve 300 and improving the reliability of the battery cell.

[0032] It should be noted that in the embodiments of the present application, existing dimension measuring tools such as vernier calipers and micrometers are used to measure the length and width of the orthographic projection of the second connecting member 210 on the second surface 122 along the thickness direction X, the length and width of the orthographic projection of the second protective film 200 on the second surface 122 along the thickness direction X, and the length and width 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, the 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 value between any two values. The smaller the value, the greater the peeling force between the second protective film 200 and the second surface 122.

[0033] When the value of (S4-S3) / S9 is in the range of 0.4~1.5, since the ratio does not exceed 1.5, it can ensure that the first protective film 400 is firmly fixed to the first surface 121 through the first connecting piece 410, ensuring that the first protective film is always located on the side of the explosion-proof valve 300 facing the accommodating chamber 130. During the movement of the cell monomer, external debris will impact the explosion-proof valve 300 and damage the explosion-proof valve 300, affecting the function of the explosion-proof valve 300. At the same time, since the ratio is not less than 0.4, it can avoid that the area of ​​the first connecting piece at the explosion-proof valve position is too large. When the explosion-proof valve is opened, the solid and liquid substances rushing out of it will adhere to the first connecting piece 410, hindering the pressure relief rate. The first connecting piece 410 will affect the pressure relief rate of the explosion-proof valve 300, while increasing the difficulty and cost of rework.

[0034] In some embodiments, the orthographic projection area of ​​the first connecting member 410 on the first surface 121 along the thickness direction X is S1 mm. 2 , satisfying 242≤S1≤1400, the orthographic projection area of ​​the first protective film 400 on the first surface 121 along the thickness direction X is S2mm 2 , satisfying: 105≤S2≤5000, the area of ​​the pressure relief port 110 on the first surface 121 is S8mm 2 , satisfying: 100≤S8≤2000.

[0035] It should be noted that the value of S1 is in the range of 242~1400, that is, the value can be any value among 242, 300, 500, 880, 1400 or a range value between any two values; the value of S2 is in the range of 105~5000, that is, the value can be any value among 370, 2200, 3000, 2200, 3000, 5000 or a range value between any two values; the value of S3 is in the range of 100~2000, that is, the value can be any value among 100, 320, 1066, 1154, 2000 or a range value between any two values.

[0036] S1, S2, and S3 satisfy the above ranges, which can ensure the bonding strength of the first protective film and reduce the difficulty of rework.

[0037] In some embodiments, the orthographic projection area of ​​the second connecting member 210 on the second surface 122 along the thickness direction X is S3 mm. 2 , satisfying: 24≤S3≤1920, the orthographic projection area of ​​the second protective film 200 on the second surface 122 along the thickness direction X is S4mm 2 , satisfying: 120≤S4≤3200, the area of ​​the pressure relief port 110 on the second surface 122 is S9mm 2 , satisfying: 100≤S9≤2000.

[0038] It should be noted that the value of S3 is in the range of 24~1920, that is, the value can be any value among 24, 107, 150, 200, 372, 400, 611, 651, 967, 1500, 1920, or a range value between any two values; the value of S4 is in the range of 120~3200, that is, the value can be any value among 120, 500, 1300, 1500, 1600, 1605, 2250, 1600, 3200, or a range value between any two values; the value of S9 is in the range of 100~2000, that is, the value can be any value among 100, 200, 320, 1066, 1154, 2000, or a range value between any two values.

[0039] S3, S4, and S9 meet the above ranges, which can ensure the bonding strength of the second protective film and reduce the difficulty of rework.

[0040] See also Figure 5 , Figure 5 Indicated Figure 4A partial enlarged schematic diagram of the middle C region. 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.

[0041] It should be noted that in the embodiments of the present application, existing dimension measuring tools such as vernier calipers and micrometers are used to measure the thickness of the first connecting member 410 along the thickness direction X and the thickness of the second connecting member 210 along the thickness direction X. The value of D1 is in the range of 0.01 to 0.1, that is, the value can be any value in 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 or a range value between any two values. The value of D2 is in the range of 0.01 to 0.1, that is, the value can be any value in 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1 or a range value between any two values. Controlling the values ​​of D1 and D2 within the above range can ensure the bonding strength while avoiding waste and increasing costs.

[0042] It should be noted that the thickness of the first connecting member 410 and the second connecting member 210 may be the same. In one embodiment, the thickness of the first connecting member 410 and the second connecting member 210 may both be 0.05 mm.

[0043] It should be noted that the first connecting member 410 and the second connecting member 210 are adhesive layers. The first connecting member 410 and the second connecting member 210 can use an adhesive layer of model 3M467, a double-sided adhesive tape under the 3M brand, or other domestic glue or double-sided adhesive tape.

[0044] In some embodiments, the orthographic projection of the first protective film 400 on the first surface 121 just covers the explosion-proof valve 300; and / or, the orthographic projection of the second protective film 200 on the second surface 122 just covers the explosion-proof valve 300. The protection effect of the explosion-proof valve 300 can be guaranteed, and at the same time, the usage of the first protective film 400 and the second protective film 200 can be reduced, thereby reducing the cost.

[0045] See also Figure 6 , Figure 6The schematic diagram of the structure of the second connector and the second protective film in the battery cell provided by the embodiment of the present application is illustrated. In some embodiments, the second protective film 200 has a plurality of air holes 220, and the air holes 220 penetrate the second protective film 200 along the thickness direction X. When the battery cell is baked at high temperature, since the internal accommodating cavity 130 is a closed space, the internal air will expand and contract due to heat, which will cause the second protective film 200 to collapse after baking. For this reason, the embodiment of the present application is provided with air holes 220, so that the internal and external air pressures of the battery cell are consistent, so as to avoid the second protective film 200 from collapsing and losing its protective effect, thereby improving the safety of the battery cell.

[0046] In some embodiments, multiple vent holes 220 are arranged in an array perpendicular to the thickness direction X. Specifically, the array arrangement of multiple vent holes 220 can further increase the speed of maintaining consistency of air pressure inside and outside the battery cell, further prevent the second protective film 200 from collapsing and losing its protective effect, and improve the safety of the battery cell.

[0047] In some embodiments, it further includes: a bottom support plate 500, which is disposed between the electrode assembly 600 and the bottom wall 120, and is connected to the housing 100; the bottom support plate 500 has an avoidance hole 510, which penetrates the bottom support plate 500 along the thickness direction X and corresponds to the position of the pressure relief port 110, and the first protective film 400 is disposed in the avoidance hole 510. In this way, the electrode assembly 600 is isolated from the bottom wall 120 by providing the bottom support plate 500 to prevent the electrode assembly 600 from short-circuiting, and the provision of the avoidance hole 510 can ensure the function of the explosion-proof valve 300 during thermal runaway.

[0048] In some embodiments, the orthographic projection area of ​​the explosion-proof valve 300 on the bottom wall 120 along the thickness direction X is S5 mm. 2 , the area of ​​the first surface 121 is S6mm 2 , the area of ​​the second surface 122 is S7 mm 2 , the battery cell satisfies: 0.01<S5 / S6≤0.5; and / or, 0.008<S5 / S7≤0.5.

[0049] It should be noted that in the embodiments of the present application, existing dimension measuring tools such as vernier calipers and micrometers are used to measure the orthographic projection of the explosion-proof valve 300 on the bottom wall 120 along the thickness direction X, the length and width of the first surface 121 and the second surface 122, and then calculate S5, S6 and S7. The value of S5 / S6 is in the range of 0.01~0.5, that is, the value can be any value among 0.01, 0.1, 0.2, 0.3, 0.4, 0.5 or the range between any two values. The value of S5 / S7 is in the range of 0.008~0.5, that is, the value can be any value among 0.008, 0.1, 0.2, 0.3, 0.4, 0.5 or the range between any two values. Under the premise of ensuring that the explosion of the explosion-proof valve 300 is normal, the production cost of the battery cell is avoided to be too high.

[0050] In some embodiments, the orthographic projection of the first protective film 400 on 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 on the second surface 122 along the thickness direction X is an ellipse or a polygon. In this way, the orthographic projection shape of the ellipse or polygon can more effectively utilize the space of the first surface 121 and the second surface 122, thereby covering the pressure relief port 110 or the explosion-proof valve 300 to the greatest extent, and providing more comprehensive protection without wasting space.

[0051] See also Figure 7 , Figure 7 The structure diagram of the explosion-proof valve in the battery cell provided by the embodiment of the present application is illustrated. In some embodiments, the battery cell further includes: a top cover sheet 800, the top cover sheet 800 is connected to the shell 100 and covers the accommodating cavity 130, and the bottom wall 120 is arranged toward the top cover sheet 800. In the embodiment of the present application, the explosion-proof valve 300 includes a welding portion 310, a weak portion 320 and a reinforcing portion 330, wherein the welding portion 310 is welded to the top cover sheet 800 to seal the pressure relief port 110, and the weak portion 320 is arranged between the welding portion 310 and the reinforcing portion 330. During the use of the battery cell, 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 and other reasons and reaches a predetermined value, the gas and high-temperature foreign matter are in place 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 are ejected in time to achieve the purpose of timely pressure relief, so as to avoid safety risks such as explosion caused by failure to timely relieve pressure. Generally speaking, the battery cell is vertical in the vehicle, that is, the top cover sheet 800 is close to the passenger compartment, and the bottom wall 120 is close to the chassis and close to the ground. In the embodiment of the present application, the pressure relief port 110 is arranged toward the top cover sheet 800, and when thermal runaway occurs, gas and high-temperature foreign matter can be discharged downward or to the side to avoid being sprayed into the passenger compartment and causing personal injury.

[0052] Next, specific embodiments of the battery cell of the present application are provided, and the present application is described in more detail through the specific embodiments.

[0053] It should be noted that the thickness of the first connecting member 410 and the second connecting member 210 in the following embodiments are both the same, which is 0.05 mm. The first connecting member 410 and the second connecting member 210 are both made of double-sided adhesive of model 3M467, a 3M brand.

[0054] Among them, the peeling force test method is: place a sample with a width of 25mm and a length greater than 175mm close to the steel plate, leave it for 20 minutes, fix the steel plate, clamp the sample with a clamp, peel the sample in a 180° direction at a speed of 300mm / min, and record the maximum force during the peeling process, which is the peeling force.

[0055] The test method for whether the burst value is normal is to fill the battery with gas until the explosion-proof valve 300 ruptures and releases pressure. The pressure when the explosion-proof valve 300 ruptures and releases pressure is the burst value. If the value is within the normal range of the battery cell of the corresponding volume model, the burst value is considered normal. If it is not within the range, the burst value is considered abnormal.

[0056] Whether the housing 100 is deformed can be confirmed by observation. If the surface of the housing 100 is cracked, dislocated, deformed, etc., it can be considered that the housing 100 is deformed.

[0057] Among them, the difficulty of rework refers to the difficulty of operation during rework and the increased cost caused. If the difficulty is increased, the rework difficulty is considered to be high. If there is no additional increase in rework difficulty and rework cost, the rework difficulty is considered to be low.

[0058] Examples 1 to 9 and Comparative Examples 1 to 2 are shown in Tables 1 to 2: Table 1

[0059] Table 2

[0060] It can be seen from the above-mentioned Examples 1-9 and Comparative Examples 1-2 that 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 difficulty of rework is low. On the contrary, when (S2-S1) / S8 is too small, the adhesion area between the first connecting member and the explosion-proof valve will be too large, which may cause damage to the explosion-proof valve during rework, increasing the difficulty and cost of rework. When (S2-S1) / S8 is too large, the first protective film is easily peeled off and the connection strength of the first protective film is too small.

[0061] It can be seen from the above-mentioned embodiments 1-9 and comparative examples 1-2 that 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 difficulty of rework is low. On the contrary, when (S4-S3) / S9 is too small, the adhesion area between the first connecting member and the explosion-proof valve will be too large, which may cause damage to the explosion-proof valve during rework, increasing the difficulty and cost of rework. When (S4-S3) / S9 is too large, the first protective film is easily peeled off and the connection strength of the first protective film is too small.

[0062] It can be seen from the above-mentioned embodiments 1-9 and comparative examples 1-2 that when the battery cell satisfies 0.01≤S5 / S6≤0.5 and 0.008≤S5 / S7≤0.5, the explosion value of the battery cell is normal and the shell will not be deformed due to insufficient strength. On the contrary, if the ratio of S5 / S6 to S5 / S7 is too small, the explosion value of the battery cell is abnormal, the battery cell cannot explode normally, and the shell will be deformed, increasing the safety risk. If the ratio of S5 / S6 to S5 / S7 is too large, the area of ​​the explosion-proof valve on the bottom wall of the shell accounts for too large a proportion, which will lead to insufficient strength of the shell.

[0063] Correspondingly, the present application also provides a battery pack, comprising a battery cell as described in any one of the above embodiments.

[0064] It can be understood that, compared with the prior art, the battery pack provided in the embodiment of the present application includes all the technical features and technical effects of the above-mentioned battery cells, which will not be repeated here.

[0065] Accordingly, the present application also provides an electric device, including a battery pack as in the above embodiment. The electric device may be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle may be a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, and the like; the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, and the like; the electric toy includes a fixed or mobile electric toy, for example, a game console, an electric car toy, an electric ship toy, and an electric airplane toy, and the like; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and an electric tool for railways, for example, an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electric devices. It is understandable that the electric device may include all the technical features and beneficial effects of the above-mentioned battery pack, which will not be repeated here.

[0066] The above is a detailed introduction to a single cell battery, a battery pack and an electrical device provided in the embodiments of the present application. Specific examples are used in the present application 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 solutions and core ideas 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 replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery cell, characterized in that: include: A housing (100) having a receiving cavity (130); An electrode assembly (600), arranged in the accommodating cavity (130); The housing (100) comprises 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 a thickness direction (X) of the bottom wall (120); An explosion-proof valve (300), the explosion-proof valve (300) being connected to the hole wall of the pressure relief port (110) and covering the pressure relief port (110); a first protective film (400) and a first connecting member (410), wherein the first protective film (400) is disposed in the accommodating cavity (130), and an 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 connecting member (410) is located between the first protective film (400) and the first surface (121) and is respectively connected to the first protective film (400) and the first surface (121), so that the first protective film (400) seals the pressure relief port (110); The orthographic projection area of ​​the first connecting member (410) on the first surface (121) along the thickness direction (X) is S1 mm. 2 The orthographic projection area of ​​the first protective film (400) on the first surface (121) along the thickness direction (X) is S2 mm 2 The area of ​​the pressure relief port (110) on the first surface (121) is S8 mm 2 ; The battery cell satisfies: 0.4≤(S2-S1) / S8≤1.

5.

2. The battery cell according to claim 1, characterized in that: Also includes: a second protective film (200) and a second connecting member (210), wherein the second protective film (200) is arranged outside the accommodating cavity (130), and the second connecting member (210) is located between the second protective film (200) and the second surface (122) and is respectively connected to the second protective film (200) and the second surface (122), so that the second protective film (200) seals the pressure relief port (110); The orthographic projection area of ​​the second connecting member (210) on the second surface (122) along the thickness direction (X) is S3 mm. 2 The orthographic projection area of ​​the second protective film (200) along the thickness direction (X) on the second surface (122) is S4 mm 2 The area of ​​the pressure relief port (110) on the second surface (122) is S9 mm 2 ; The battery cell meets: 0.4≤(S4-S3) / S9≤1.

5.

3. The battery cell according to claim 1, characterized in that: The battery cell meets one or more of the following conditions: (a) 242≤S1≤1400; (b) 105≤S2≤5000; (c) 100≤S8≤2000.

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

5. The battery cell according to claim 2, characterized in that: The orthographic projection of the first protective film (400) on the first surface (121) coincides with the explosion-proof valve (300); and / or, The orthographic projection of the second protective film (200) on the second surface (122) coincides with the explosion-proof valve (300).

6. The battery cell according to claim 2, characterized in that: The second protective film (200) has a plurality of air holes (220), and the air holes (220) penetrate the second protective film (200) along the thickness direction (X).

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

8. The battery cell according to claim 1, characterized in that: Also includes: A bottom supporting plate (500), the bottom supporting plate (500) being arranged between the electrode assembly (600) and the bottom wall (120), and the bottom supporting plate (500) being connected to the housing (100); The bottom support plate (500) has an avoidance hole (510), the avoidance hole (510) penetrates the bottom support plate (500) along the thickness direction (X) and corresponds to the position of the pressure relief port (110), and the first protective film (400) is arranged in the avoidance hole (510).

9. The battery cell according to claim 1, characterized in that: The orthographic projection area of ​​the explosion-proof valve (300) on the bottom wall (120) along the thickness direction (X) is S5 mm 2 , the area of ​​the first surface (121) is S6mm 2 , the area of ​​the second surface (122) is S7mm 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.

10. The battery cell according to claim 9, characterized in that: The battery cell meets one or more of the following conditions: (i) 100≤S5≤2800; (j) 1000≤S6≤50000; (k) 1200≤S7≤70000.

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

1.

12. The battery cell according to claim 2, characterized in that: The orthographic projection of the first protective film (400) along the thickness direction (X) on the first surface (121) is an ellipse or a polygon, and / or the orthographic projection of the second protective film (200) along the thickness direction (X) on the second surface (122) is an ellipse or a polygon.

13. The battery cell according to any one of claims 1 to 12, characterized in that: Also includes: A top cover sheet (800), the top cover sheet (800) is connected to the shell (100) and covers the accommodating cavity (130), and the bottom wall (120) is arranged opposite to the top cover sheet (800).

14. A battery pack, characterized in that: The invention comprises a battery cell as claimed in any one of claims 1 to 13.

15. An electrical equipment, characterized in that: Comprising the battery pack as claimed in claim 14.

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