Pressure relief mechanism, battery cell and power utilization device

Abstract

The embodiment of the invention provides a pressure relief mechanism, a battery cell and a power utilization device, and relates to the technical field of batteries. The pressure relief mechanism comprises an adhesive film and a first metal sheet, and the first metal sheet is arranged on one side of the adhesive film and bonded with the adhesive film. Wherein the pressure relief mechanism is used for pressure relief of the battery cell, and the adhesive film can be fused when the temperature reaches a threshold value. The adhesive film is arranged in the shell of the battery cell, so that when the pressure relief mechanism is arranged in the shell of the battery cell, the adhesive film can be heated and melted to form a pressure relief channel for communicating the inside and the outside of the shell of the battery cell, the thermal sensitivity of the pressure relief mechanism is better, the pressure relief reliability is higher, the safety of the battery cell can be improved, and compared with a nick groove pressure relief structure, the embodiment does not need to reserve a large space and is convenient to use. The structure of the electric device can be more compact, and the cost for preparing the pressure relief mechanism is lower. The first metal sheet can reduce the water seepage area of the adhesive film, so that the sealing effect is better.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a pressure relief mechanism, a battery cell and an electrical device. Background Art

[0002] With the rapid development of new energy technologies, batteries have been widely used in electronic equipment, electric vehicles, electric two-wheelers, power tools, etc. The requirements for battery quality, safety, and miniaturization are becoming increasingly higher.

[0003] At present, in order to improve the safety of steel shell batteries, laser grooves are used to vent the battery when the internal pressure is too high. The electrical device equipped with the steel shell battery needs to reserve a larger valve opening space corresponding to the groove, which makes the overall space occupied by the electrical device larger. In addition, the thermal sensitivity of the groove is poor, resulting in poor reliability of pressure relief, affecting the safety of the battery. Laser grooves will also increase the preparation cost of the battery. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a pressure relief mechanism, a battery cell and an electrical device. The pressure relief mechanism provided by the embodiments of the present application can improve the reliability of pressure relief of the battery cell and increase the space utilization rate of the electrical device.

[0005] This application is achieved through the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides a pressure relief mechanism, which includes an adhesive film and a first metal sheet, wherein the first metal sheet is arranged on one side of the adhesive film and is bonded to the adhesive film; wherein the pressure relief mechanism is used to relieve pressure on the battery cell, and the adhesive film can melt when the temperature reaches a threshold value.

[0007] In the above technical solution, the pressure relief mechanism includes a film and a first metal sheet, and the first metal sheet is arranged on one side of the film and bonded to the film, so that when the pressure relief mechanism is arranged in the shell of the battery cell, the film can be melted by heat to form a pressure relief channel connecting the inside and outside of the battery cell shell. The thermal sensitivity of the pressure relief mechanism is good, so that the reliability of the pressure relief is high, and the safety of the battery cell can be improved. Compared with the notched groove pressure relief structure, this embodiment does not need to reserve a large space, which can make the structure of the electrical device more compact and the cost of preparing the pressure relief mechanism is lower. The first metal sheet can reduce the water seepage area of ​​the film, so that the sealing effect is better.

[0008] In some embodiments of the present application, the pressure relief mechanism further includes a second metal sheet, and the second metal sheet is disposed on a side of the adhesive film facing away from the first metal sheet.

[0009] In some embodiments of the present application, the melting point of the adhesive film is 100°C to 130°C.

[0010] In the above technical solution, by making the melting point of the adhesive film be 100℃~130℃, the adhesive film can melt to form a pressure relief channel when the battery cell is in thermal runaway; if T1 is small (such as less than 100℃), the adhesive film may melt before the battery cell reaches thermal runaway, and the sealing reliability of the adhesive film is low; if T1 is large (such as greater than 130℃), the adhesive film is difficult to melt when the battery cell is in thermal runaway, and the sensitivity of the battery cell pressure relief is low.

[0011] In some embodiments of the present application, the adhesive film includes a first adhesive layer and a second adhesive layer, the first adhesive layer and the second adhesive layer are stacked, the second adhesive layer is located on the side of the first adhesive layer facing the first metal sheet, and the melting point of the first adhesive layer is lower than the melting point of the second adhesive layer.

[0012] In the above technical solution, by setting the first glue layer and the second glue layer, and making the melting point of the first glue layer lower than the melting point of the second glue layer, when the glue film is activated by high temperature, the first glue layer can melt to fit with the shell of the battery cell, while the second glue layer will not melt, which can avoid the glue film from over-melting and affecting the installation of the glue film, and can also reduce the amount of glue overflow.

[0013] In some embodiments of the present application, the adhesive film further includes a third adhesive layer, the third adhesive layer is located between the second adhesive layer and the first metal sheet, and the melting point of the third adhesive layer is lower than the melting point of the second adhesive layer.

[0014] In the above technical solution, by setting a third adhesive layer and making the melting point of the third adhesive layer lower than that of the second adhesive layer, when the adhesive film is activated by high temperature, the third adhesive layer can melt to adhere to the first metal sheet, while the second adhesive layer will not melt, thereby preventing the adhesive film from over-melting and affecting the installation of the first metal sheet, and reducing the amount of glue overflow.

[0015] In some embodiments of the present application, the first adhesive layer, the second adhesive layer, and the third adhesive layer satisfy at least one of the following conditions:

[0016] (1) The melting point of the first adhesive layer is T1, which satisfies 100°C ≤ T1 ≤ 130°C;

[0017] (2) The melting point of the second adhesive layer is T2, which satisfies 140°C ≤ T2 ≤ 190°C;

[0018] (3) The melting point of the third adhesive layer is T3, which satisfies 100°C≤T3≤130°C.

[0019] In the above technical solution, by setting the melting point of the first adhesive layer at 100°C to 130°C, the first adhesive layer can melt to form a pressure relief channel when the battery cell is in thermal runaway; if T1 is small (such as less than 100°C), the first adhesive layer may melt before the battery cell reaches thermal runaway, and the sealing reliability of the adhesive film is low; if T1 is large (such as greater than 130°C), the first adhesive layer is difficult to melt when the battery cell is in thermal runaway, and the sensitivity of the battery cell to pressure relief is low.

[0020] By setting the melting point of the second adhesive layer at 140°C to 190°C, the second adhesive layer will not melt when the first adhesive layer melts. If T2 is small (such as less than 140°C), the first adhesive layer and the second adhesive layer may melt at the same time and mix into one when the adhesive film is activated by high temperature, making the installation of the adhesive film difficult. If T2 is large (such as greater than 190°C), the second adhesive layer will also be difficult to melt when the battery cell experiences excessive thermal runaway, and the sensitivity of the battery cell to pressure relief is low.

[0021] By setting the melting point of the third adhesive layer at 100°C to 130°C, the third adhesive layer can melt to form a pressure relief channel with the first metal sheet when the battery cell is in thermal runaway; if T3 is small (such as less than 100°C), the third adhesive layer may melt before the battery cell reaches thermal runaway, and the sealing reliability of the adhesive film is low; if T3 is large (such as greater than 130°C), the third adhesive layer is difficult to melt when the battery cell is in thermal runaway, and the sensitivity of the battery cell to pressure relief is low.

[0022] In some embodiments of the present application, the thickness of the adhesive film is H, satisfying 0.05 mm ≤ H ≤ 0.5 mm.

[0023] In the above technical solution, by setting the thickness of the adhesive film to 0.05 mm to 0.5 mm, the adhesive film can be made not easy to be damaged or water-permeable, and the pressure relief effect is better; if H is small (such as less than 0.05 mm), the adhesive film is easy to be damaged, and the water permeability is too high; if H is large (such as greater than 0.5 mm), the adhesive film is difficult to melt when the battery cell is thermally runaway, and the sensitivity of the battery cell pressure relief is low.

[0024] In some embodiments of the present application, 0.1 mm≤H≤0.3 mm.

[0025] In the above technical solution, by setting the thickness of the adhesive film to 0.1 mm ≤ H ≤ 0.3 mm, the adhesive film can be further made less prone to damage and water permeability, and has a better pressure relief effect.

[0026] In a second aspect, an embodiment of the present application provides a battery cell, comprising a shell, a pole and a pressure relief mechanism, wherein the shell comprises a bottom wall and a plurality of side walls surrounding the bottom wall, wherein a first side wall of the plurality of side walls is provided with a first through hole and a second through hole. The pressure relief mechanism covers the first through hole, and the pressure relief mechanism is the pressure relief mechanism described above. The pole is passed through the second through hole. The adhesive film can melt when the temperature of the battery cell reaches a threshold value, so that the pressure inside the shell is released through the first through hole.

[0027] In the above technical solution, a pressure relief mechanism including a film is provided to cover the first through hole of the shell, so that the film can melt when the temperature of the battery cell reaches a threshold value to release the pressure inside the shell through the first through hole. The thermal sensitivity of the pressure relief mechanism is good, so that the reliability of the pressure relief is high, and the safety of the battery cell can be improved. In addition, the first through hole and the second through hole for installing the pole are both located on the first side wall, so that the pressure relief mechanism can use the space reserved for the pole, which can save space for the electrical device equipped with the battery cell, make the structure of the electrical device more compact, and the cost of preparing the pressure relief mechanism is lower.

[0028] In some embodiments of the present application, the battery cell also includes a first insulating member, which is located on the inner side of the first side wall, connected to the pole, and provided with a channel connecting the internal space of the shell and the pressure relief mechanism.

[0029] In the above technical solution, by providing a channel connecting the internal space of the shell and the pressure relief mechanism on the first insulating member, the first through hole can be less likely to be blocked during the pressure relief process, the pressure relief effect is better, and the safety of the battery cell pressure relief is higher.

[0030] In some embodiments of the present application, the channel is a groove provided on a side of the first insulating member facing the first side wall, and at least one end of the groove extends to an edge of the first insulating member.

[0031] In the above technical solution, by setting the channel as a groove on the side of the first insulating member facing the first side wall, the distance between the first through hole and the channel can be shortened, further reducing the possibility of the channel being blocked, achieving a better pressure relief effect and higher safety of battery cell pressure relief.

[0032] In some embodiments of the present application, the groove penetrates the first insulating member along a width direction of the first insulating member.

[0033] In the above technical solution, the air on both sides of the first insulating member along the width direction of the first insulating member can flow to the first through hole through the channel, the air flow rate is faster during the pressure relief process, and the pressure relief can still be achieved when the first insulating member is blocked on either side along the width direction of the first insulating member, and the reliability of the pressure relief of the battery cell is higher.

[0034] In some embodiments of the present application, the depth of the groove is A, satisfying: 0.05mm≤A≤0.5mm.

[0035] In the above technical solution, by setting the depth A of the channel to 0.05mm to 0.5mm, the first insulating component can have a larger cross-sectional area of ​​the channel and a faster pressure relief speed without occupying too much space inside the shell; if A is smaller (such as less than 0.05mm), the cross-sectional area of ​​the channel is smaller and easily blocked, and the pressure relief speed is too slow, affecting the safety of pressure relief; if A is larger (such as greater than 0.5mm), the size of the first insulating component will be too large, occupying more space inside the shell, squeezing the installation space of other components in the shell.

[0036] In some embodiments of the present application, 0.1 mm≤A≤0.2 mm.

[0037] In the above technical solution, by setting the depth A of the channel to 0.1 mm to 0.2 mm, the cross-sectional area of ​​the channel can be further increased without occupying too much space inside the shell.

[0038] In some embodiments of the present application, the diameter of the first through hole is B, and the width of the groove is C, satisfying: 0.8*B≤C.

[0039] In the above technical solution, by setting C to be greater than or equal to 0.8*B, the connecting area between the channel and the first through hole is larger and the pressure relief speed is faster; if C is smaller (such as less than 0.8*B), the connecting area between the channel and the first through hole is smaller and easily blocked, and the pressure relief speed is too slow, affecting the safety of pressure relief.

[0040] In some embodiments of the present application, B≤C≤2*B.

[0041] In the above technical solution, by setting C at B to 2*B, the connecting area between the channel and the first through hole can be further increased.

[0042] In some embodiments of the present application, the battery cell further includes an electrode assembly and a transition piece, both of which are disposed in the housing, the transition piece is used to electrically connect the electrode assembly and the pole, and the first insulating member is located between the first side wall and the transition piece. The first insulating member is provided with a third through hole, the transition piece is provided with a fourth through hole, the pole is passed through the third through hole and the fourth through hole and is riveted to the transition piece.

[0043] In the above technical solution, by allowing the pole to pass through the first insulating member and the adapter and to be riveted to the adapter, the connection between the pole and the adapter can be made more stable, and the first insulating member can play the role of insulating and isolating the adapter and the shell.

[0044] In some embodiments of the present application, the battery core further includes a second insulating member, at least a portion of the second insulating member is located outside the first side wall, the second insulating member is provided with a fifth through hole, and the pole is passed through the fifth through hole.

[0045] In the above technical solution, by passing the pole through the second insulating member, the second insulating member can play the role of insulating and isolating the pole and the shell.

[0046] In some embodiments of the present application, the adhesive film includes a first adhesive segment and a second adhesive segment that are connected, the first adhesive segment is located outside the first side wall, and at least a portion of the second adhesive segment is located in the first through hole.

[0047] In the above technical solution, by dividing the adhesive film into a first adhesive segment and a second adhesive segment, and at least part of the second adhesive segment is located in the first through hole, the first adhesive segment can fit with the shell, and the second adhesive segment can block the first through hole, thereby achieving a better sealing effect on the first through hole.

[0048] In some embodiments of the present application, the adhesive film further includes a third adhesive segment connected to a side of the second adhesive segment away from the first adhesive segment, and the third adhesive segment is located on an inner side of the first side wall.

[0049] In the above technical solution, by dividing the adhesive film into three adhesive segments, and making the third adhesive segment located inside the first side wall, the size of the third adhesive segment is larger than that of the second adhesive segment, so that the adhesive film can be better fixed on the shell, the adhesive film is not easy to fall off, and the sealing reliability of the first through hole is better.

[0050] In some embodiments of the present application, the first through hole is circular, and the diameter of the first through hole is B, satisfying 0.5 mm ≤ B ≤ 3 mm.

[0051] In the above technical solution, by setting the diameter B of the first through hole to 0.5mm to 3mm, the first through hole can provide a pressure relief channel with a larger cross-sectional area when the battery cell is in thermal runaway, and it is convenient to install the pressure relief mechanism; if B is smaller (such as less than 0.5mm), the cross-sectional area of ​​the pressure relief channel formed by the melting of the film when the battery cell reaches thermal runaway is smaller, the gas in the shell may not be released in time, and the safety of the battery cell pressure relief is low; if B is larger (such as greater than 3mm), a pressure relief mechanism with a larger area is required to cover the first through hole, making the installation of the pressure relief mechanism difficult.

[0052] In some embodiments of the present application, 0.9 mm ≤ B ≤ 1.6 mm.

[0053] In the above technical solution, by setting the diameter B of the first through hole to 0.9 mm to 1.6 mm, a pressure relief channel with a larger cross-sectional area can be further provided, and the installation of the pressure relief mechanism is facilitated.

[0054] In some embodiments of the present application, the width of the portion where the adhesive film is bonded to the first side wall is W, satisfying 0.2 mm ≤ W ≤ 2 mm.

[0055] In the above technical solution, by setting the width W of the portion where the adhesive film adheres to the first side wall to 0.2 mm to 2 mm, the length of the pressure relief path of the battery cell can be shorter during thermal runaway, the sensitivity of the battery cell to pressure relief can be higher, and at the same time, the sealing reliability of the adhesive film to the first through hole can be higher; if W is smaller (such as less than 0.2 mm), the sealing reliability of the adhesive film to the first through hole is lower; if W is larger (such as greater than 2 mm), the length of the pressure relief path is longer, and the sensitivity of the battery cell to pressure relief is lower.

[0056] In some embodiments of the present application, 0.3 mm ≤ W ≤ 1 mm.

[0057] In the above technical solution, by setting the width W of the portion where the adhesive film adheres to the first side wall to 0.3 mm to 1 mm, the length of the pressure relief path of the battery cell can be further shortened during thermal runaway, and the sensitivity of the pressure relief of the battery cell can be higher.

[0058] In a second aspect, an embodiment of the present application provides an electrical device, comprising a battery cell as described above, wherein the battery cell is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0060] Figure 1 A schematic top view of a partial structure of an electrical device provided in some embodiments of the present application;

[0061] Figure 2 A schematic diagram of the three-dimensional structure of a pressure relief mechanism provided in some embodiments of the present application;

[0062] Figure 3 A schematic diagram of the explosion structure of the pressure relief mechanism provided in some embodiments of the present application;

[0063] Figure 4 A schematic diagram of a three-dimensional structure of a battery cell provided in some embodiments of the present application;

[0064] Figure 5 An exploded schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application;

[0065] Figure 6 A schematic diagram of a three-dimensional structure of a pressure relief mechanism provided in some other embodiments of the present application;

[0066] Figure 7 A schematic diagram of the explosion structure of the pressure relief mechanism provided in some other embodiments of the present application;

[0067] Figure 8 A schematic cross-sectional structural diagram of a rubber film of a pressure relief mechanism provided in some embodiments of the present application;

[0068] Fig. 9 A schematic diagram of the main structure of the adhesive film provided in some other embodiments of the present application;

[0069] Fig.10 A schematic diagram of an exploded structure of a battery cell provided in some embodiments of the present application;

[0070] Fig.11 A schematic diagram of a three-dimensional structure of a battery cell provided in some embodiments of the present application;

[0071] Fig.12 A schematic diagram of an exploded structure of a battery cell provided in some embodiments of the present application;

[0072] Fig.13 A schematic top view of the structure of a first insulating member provided in some embodiments of the present application;

[0073] Fig.14 A schematic diagram of the main structure of a first insulating member provided in some embodiments of the present application;

[0074] Fig.15 A schematic diagram of the main structure of a battery cell provided in some embodiments of the present application;

[0075] Fig.16 A bottom-up structural schematic diagram of a battery cell provided in some embodiments of the present application;

[0076] Fig.17 for Fig.16 A schematic diagram of the cross-sectional structure along the X1-X1 direction;

[0077] Fig.18 for Fig.16 A schematic diagram of the cross-sectional structure along the X2-X2 direction;

[0078] Fig.19A schematic cross-sectional view of a partial structure of a battery cell provided in some embodiments of the present application;

[0079] Fig. 20 A schematic cross-sectional view of a partial structure of a battery cell provided in some embodiments of the present application.

[0080] Icons: 10-battery cell; 100-shell; 101-first through hole; 102-second through hole; 110-bottom wall; 121-first side wall; 122-second side wall; 123-third side wall; 124-fourth side wall; 200-shell cover; 300-pressure relief mechanism; 310-adhesive film; 311-first adhesive layer; 312-second adhesive layer; 313-third adhesive layer; 310a-first adhesive section; 310b second adhesive section; 310c third adhesive section; 320-first metal sheet; 330-second metal sheet; 400-pole; 410-first insulating member; 411-groove; 412-third through hole; 420-adapter; 421-fourth through hole; 430-second insulating member; 431-fifth through hole; 20-casing. DETAILED DESCRIPTION

[0081] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of this application.

[0082] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0083] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" 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 direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0084] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0085] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0086] In the present application, each battery cell can be a secondary battery or a primary battery; for example, the battery cell can be a lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, etc., which is not limited in the present application. The battery cell can be cylindrical, flat, rectangular, or in other shapes, which is not limited in the present application.

[0087] The electrode assembly may be a wound structure or a laminated structure, which is not limited in the embodiments of the present application.

[0088] The inventors have found that for general steel shell batteries, the notched groove is mainly formed by laser notching on the shell cover, so that when the internal air pressure of the battery cell is too high, the notched groove can be broken to form a pressure relief channel to discharge the gas inside the battery cell, which plays an explosion-proof role and can improve the safety of the battery cell. However, in order to allow the gas inside the battery cell to be discharged smoothly after the notched groove is broken, it is generally necessary to reserve a valve opening space in the part of the electrical device corresponding to the notched groove, and because the shell cover is the side with the largest area of ​​the battery cell shell, the length of the notched groove is also long, so in order to reserve space between the shell cover and other components, a large space in the electrical device will be occupied. In addition, the notched groove mainly relies on the air pressure inside the battery cell to cause rupture, and has poor thermal sensitivity. The pass rate of the hot box test is low, which affects the safety of the battery cell. At the same time, laser notching will also increase the preparation cost of the battery cell.

[0089] Based on the above considerations, in order to solve the problems of excessive space occupation, low safety of pressure relief and high preparation cost caused by the current pressure relief of battery cells through notched grooves, the inventors have designed a pressure relief mechanism after in-depth research. The pressure relief mechanism includes a film and a first metal sheet. The first metal sheet is arranged on one side of the film and bonded to the film. The pressure relief mechanism is used for pressure relief of the battery cell, and the film can melt when the temperature reaches a threshold. When the pressure relief mechanism is arranged in the shell of the battery cell, the film can melt under heat to form a pressure relief channel connecting the inside and outside of the battery cell shell. The pressure relief mechanism has good thermal sensitivity, which makes the reliability of pressure relief higher and can improve the safety of the battery cell. Compared with the notched groove pressure relief structure, this embodiment does not need to reserve a large space, which can make the structure of the electrical device more compact and the cost of preparing the pressure relief mechanism is lower. The first metal sheet can reduce the water seepage area of ​​the film, so that the sealing effect is better.

[0090] The present application embodiment provides an electric device using a battery cell as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. For example, in Figure 1 middle, Figure 1 This is a schematic top view of a partial structure of an electrical device provided in some embodiments of the present application. The battery cell 10 is a rectangular parallelepiped structure and is accommodated in a housing 20 .

[0091] Please refer to Figures 2 to 5 , Figure 2 A schematic diagram of a three-dimensional structure of a pressure relief mechanism provided in some embodiments of the present application, Figure 3 A schematic diagram of the explosion structure of the pressure relief mechanism provided in some embodiments of the present application, Figure 4 A schematic diagram of a three-dimensional structure of a battery cell provided in some embodiments of the present application. Figure 5 An exploded schematic diagram of a partial structure of a battery cell provided in some embodiments of the present application.

[0092] The embodiment of the present application provides a pressure relief mechanism 300, which includes an adhesive film 310 and a first metal sheet 320. The first metal sheet 320 is arranged on one side of the adhesive film 310 and is bonded to the adhesive film 310. The pressure relief mechanism 300 is used to relieve pressure on the battery cell 10, and the adhesive film 310 can melt when the temperature reaches a threshold.

[0093] By making the pressure relief mechanism 300 include the adhesive film 310 and the first metal sheet 320, the first metal sheet 320 is arranged on one side of the adhesive film 310 and bonded to the adhesive film 310, so that when the pressure relief mechanism 300 is arranged on the shell 100 of the battery cell 10, the adhesive film 310 can be melted by heat to form a pressure relief channel connecting the inside and outside of the battery cell shell 100, the pressure relief mechanism 300 has good thermal sensitivity, so that the reliability of pressure relief is high, and the safety of the battery cell 10 can be improved. Compared with the notched groove pressure relief structure, this embodiment does not need to reserve a large space, which can make the structure of the electric device more compact, and the cost of preparing the pressure relief mechanism 300 is lower. The first metal sheet 320 can reduce the water seepage area of ​​the adhesive film 310, so that the sealing effect is better.

[0094] Please refer to Figure 6 and Figure 7 , Figure 6 Schematic diagram of the three-dimensional structure of the pressure relief mechanism provided in some other embodiments of the present application, Figure 7 Schematic diagram of the explosion structure of the pressure relief mechanism provided in other embodiments of the present application.

[0095] In some embodiments, the pressure relief mechanism 300 further includes a second metal sheet 330 . The second metal sheet 330 is disposed on a side of the adhesive film 310 facing away from the first metal sheet 320 .

[0096] In some embodiments, the melting point of the adhesive film 310 is 100° C. to 130° C.

[0097] By setting the melting point of the adhesive film 310 to 100°C to 130°C, the adhesive film 310 can melt to form a pressure relief channel when the battery cell 10 is in thermal runaway. If T1 is small (such as less than 100°C), the adhesive film 310 may melt before the battery cell 10 reaches thermal runaway, and the sealing reliability of the adhesive film 310 is low. If T1 is large (such as greater than 130°C), the adhesive film 310 is difficult to melt when the battery cell 10 is in thermal runaway, and the sensitivity of the pressure relief of the battery cell 10 is low.

[0098] Please refer to Figure 8 , Figure 8 A schematic diagram of the cross-sectional structure of the adhesive film of the pressure relief mechanism provided in some embodiments of the present application.

[0099] In some embodiments, the adhesive film 310 may include a first adhesive layer 311 and a second adhesive layer 312 , the first adhesive layer 311 and the second adhesive layer 312 are stacked, the second adhesive layer 312 is located on the side of the first adhesive layer 311 facing away from the shell 100 , and the melting point of the first adhesive layer 311 is lower than the melting point of the second adhesive layer 312 .

[0100] By providing the first adhesive layer 311 and the second adhesive layer 312, and making the melting point of the first adhesive layer 311 lower than the melting point of the second adhesive layer 312, when the adhesive film 310 is activated by high temperature, the first adhesive layer 311 can melt to fit with the shell 100, while the second adhesive layer 312 will not melt, thereby preventing the adhesive film 310 from over-melting and affecting the installation of the adhesive film 310, and reducing the amount of adhesive overflow.

[0101] In some embodiments, the adhesive film 310 may further include a third adhesive layer 313 , the third adhesive layer 313 is located between the second adhesive layer 312 and the first metal sheet 320 , and the melting point of the third adhesive layer 313 is lower than the melting point of the second adhesive layer 312 .

[0102] By providing the third adhesive layer 313 and making the melting point of the third adhesive layer 313 lower than the melting point of the second adhesive layer 312, when the adhesive film 310 is activated by high temperature, the third adhesive layer 313 can melt to adhere to the first metal sheet 320, while the second adhesive layer 312 will not melt, thereby preventing the adhesive film 310 from over-melting and affecting the installation of the first metal sheet 320, and reducing the amount of adhesive overflow.

[0103] In some embodiments, the melting point of the first adhesive layer 311 may be T1, satisfying 100° C. ≤ T1 ≤ 130° C.

[0104] By setting the melting point of the first adhesive layer 311 at 100°C to 130°C, the first adhesive layer 311 can melt to form a pressure relief channel when the battery cell 10 is in thermal runaway; if T1 is small (such as less than 100°C), the first adhesive layer 311 may melt before the battery cell 10 reaches thermal runaway, and the sealing reliability of the adhesive film 310 is low; if T1 is large (such as greater than 130°C), the first adhesive layer 311 is difficult to melt when the battery cell 10 is in thermal runaway, and the battery cell 10 has low sensitivity to pressure relief.

[0105] In some embodiments, 110° C. ≤ T1 ≤ 125° C., and the thermal runaway of the battery cell 10 can be controlled more accurately.

[0106] In some embodiments, the melting point of the second adhesive layer 312 is T2, which satisfies 140° C. ≤ T2 ≤ 190° C.

[0107] By setting the melting point of the second adhesive layer 312 at 140°C to 190°C, the second adhesive layer 312 will not melt when the first adhesive layer 311 melts. If T2 is small (such as less than 140°C), the first adhesive layer 311 and the second adhesive layer 312 may melt at the same time and mix together when the adhesive film 310 is activated by high temperature, making it difficult to install the adhesive film 310. If T2 is large (such as greater than 190°C), the second adhesive layer 312 will also be difficult to melt when the battery cell 10 has excessive thermal runaway, and the battery cell 10 has low sensitivity to pressure relief.

[0108] In some embodiments, 150° C. ≤ T2 ≤ 170° C., and thermal runaway of the battery cell 10 can be more accurately controlled.

[0109] In some embodiments, the melting point of the third adhesive layer 313 is T3, satisfying 100° C.≤T3≤130° C.

[0110] By setting the melting point of the third adhesive layer 313 at 100°C to 130°C, the third adhesive layer 313 can melt to form a pressure relief channel with the first metal sheet 320 when the battery cell 10 is in thermal runaway; if T3 is small (such as less than 100°C), the third adhesive layer 313 may melt before the battery cell 10 reaches thermal runaway, and the sealing reliability of the adhesive film 310 is low; if T3 is large (such as greater than 130°C), the third adhesive layer 313 is difficult to melt when the battery cell 10 is in thermal runaway, and the battery cell 10 has low sensitivity to pressure relief.

[0111] In some embodiments, 110° C. ≤ T3 ≤ 125° C., and the thermal runaway of the battery cell 10 can be controlled more accurately.

[0112] In some embodiments, the thickness ratio of the first adhesive layer 311 , the second adhesive layer 312 , and the third adhesive layer 313 may be 1:0.5:1 to 1:3:1.

[0113] By setting the thickness ratio of the first adhesive layer 311, the second adhesive layer 312, and the third adhesive layer 313 to 1:0.5:1 to 1:3:1, the second adhesive layer 312 can have a good supporting effect while having little effect on the pressure relief effect of the adhesive film 310; if the second adhesive layer 312 is thinner (such as less than 0.5 times the thickness of the first adhesive layer 311), the second adhesive layer 312 cannot have a good supporting effect, and it is not convenient for the adhesive laminating device (not shown in the figure) to support the second adhesive layer 312 during the melting of the first adhesive layer 311 to avoid the displacement of the adhesive film 310, and the second adhesive layer 312 is easily damaged, and it is not convenient to install the adhesive film 310; if the second adhesive layer 312 is thicker (such as greater than 3 times the thickness of the first adhesive layer), it may affect the melting of the first adhesive layer 311, and further affect the sensitivity of the pressure relief of the battery cell 10.

[0114] In some embodiments, the thickness of the adhesive film 310 may be H, satisfying 0.05 mm ≤ H ≤ 0.5 mm.

[0115] By setting the thickness of the adhesive film 310 to 0.05 mm to 0.5 mm, the adhesive film 310 can be made less prone to damage and water permeability, and the pressure relief effect is better; if H is smaller (such as less than 0.05 mm), the adhesive film 310 is easily damaged and the water permeability is too high; if H is larger (such as greater than 0.5 mm), the adhesive film 310 is difficult to melt when the battery cell 10 thermally runs away, and the sensitivity of the pressure relief of the battery cell 10 is low.

[0116] In some embodiments, 0.1 mm ≤ H ≤ 0.3 mm, which can further make the adhesive film 310 less prone to damage and water permeability, and has a better pressure relief effect, and can more accurately control the thermal runaway of the battery cell 10 .

[0117] Please refer to Figure 4 and Figure 5 The battery cell 10 includes a housing 100, a housing cover 200, an electrode assembly (not shown in the figure) and an electrolyte (not shown in the figure). The housing cover 200 is used to cover the housing 100 to form a housing space, and the housing space is used to accommodate the electrode assembly and the electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work.

[0118] Reference Figures 1 to 3 An embodiment of the present application provides a battery cell 10, which includes a shell 100 and a pressure relief mechanism 300 provided in any of the above embodiments. The shell 100 is provided with a first through hole 101, and the pressure relief mechanism 300 covers the first through hole 101. The adhesive film 310 can be melted by heat to form a pressure relief channel connecting the inside and outside of the shell 100.

[0119] By setting the pressure relief mechanism 300 to cover the first through hole 101 of the shell 100, the adhesive film 310 can be melted by heat to form a pressure relief channel connecting the inside and the outside of the shell 100. The pressure relief mechanism 300 has good thermal sensitivity, so that the reliability of pressure relief is high, which can improve the safety of the battery cell 10. Compared with the notched groove pressure relief structure, the size of the first through hole 101 in this embodiment is smaller, and there is no need to reserve a large space, which can make the structure of the electrical device more compact. The preparation of the pressure relief mechanism 300 only requires steps such as drilling and melting glue, which is lower in cost than laser notching.

[0120] In some embodiments, the first through hole 101 may be a liquid injection hole, and the electrolyte is injected into the battery cell 10 through the first through hole 101 .

[0121] Reusing the injection hole as the first through hole 101 for pressure relief can further simplify the preparation process of the battery cell 10 , reduce the number of drilling steps, and reduce the preparation cost of the battery cell 10 .

[0122] In other embodiments, the first through hole 101 may also be other through holes formed in the housing 100 .

[0123] Please refer to Figure 8 In some embodiments, the first through hole 101 is circular, and the diameter of the first through hole 101 is D, satisfying 0.5 mm ≤ D ≤ 2 mm.

[0124] By setting the diameter of the first through hole 101 to 0.5 mm to 2 mm, the first through hole 101 can provide a pressure relief channel with a larger cross-sectional area when the battery cell 10 is in thermal runaway, and the installation of the pressure relief mechanism 300 is facilitated; if D is small (such as less than 0.5 mm), the cross-sectional area of ​​the pressure relief channel formed by the melting of the adhesive film 310 when the battery cell 10 reaches thermal runaway is small, and the gas in the shell 100 may not be released in time, and the safety of the pressure relief of the battery cell 10 is low; if D is large (such as greater than 2 mm), a larger area of ​​the pressure relief mechanism 300 is required to cover the first through hole 101, and the adhesive film 310 is a flexible material with weak supporting force, which will make the installation of the pressure relief mechanism 300 difficult.

[0125] In some embodiments, 0.9 mm ≤ D ≤ 1.6 mm, which can further enable the first through hole 101 to provide a pressure relief channel with a larger cross-sectional area when the battery cell is in thermal runaway, and facilitate the installation of the pressure relief mechanism 300 .

[0126] In some embodiments, the shell 100 includes a bottom wall 110 and multiple side walls surrounding the bottom wall 110. The multiple side walls may include a first side wall 121, a second side wall 122, a third side wall 123 and a fourth side wall 124 connected in sequence. The battery cell 10 may also include a pole 400. The pole 400 and the first through hole 101 are arranged on the same side wall (for example, the first side wall 121).

[0127] When the battery cell 10 is installed in an electrical device, space needs to be reserved to facilitate electrical connection between the pole 400 and other components of the electrical device, so that the electrode assembly in the shell 100 can be electrically connected to other components. Therefore, the pole 400 and the first through hole 101 are arranged on the same side wall, and there is no need to reserve additional space for the first through hole 101 to achieve pressure relief. In addition, the first side wall 121 can be the smallest wall among the multiple walls of the shell 100, and the interval space that needs to be reserved is also smaller, which can further save space in the electrical device and make the structure of the electrical device more compact.

[0128] In some embodiments, the first metal sheet 320 and the adhesive film 310 are stacked along the opening direction of the first through hole 101 (ie, the wall thickness direction of the first side wall 121 ), and the first metal sheet 320 is disposed on a side of the adhesive film 310 facing away from the housing 100 .

[0129] Since the adhesive film 310 is a high molecular polymer and is water permeable, when moisture enters the shell 100 through the adhesive film 310, it will have an adverse effect on the electrode assembly and the electrolyte. By setting a first metal sheet 320 on the side of the adhesive film 310 facing away from the shell 100, the water seepage area of ​​the adhesive film 310 can be reduced, thereby achieving a better sealing effect.

[0130] In some embodiments, the adhesive film 310 may be made of polypropylene, which has good toughness and good chemical resistance.

[0131] In some embodiments, the first metal sheet 320 can be made of aluminum, nickel, stainless steel or other materials, which is not easy to rust and has a long service life.

[0132] In some embodiments, the first metal sheet 320 may be arranged in a circular shape, the adhesive film 310 may be arranged in a circular shape, and the first through hole 101 may be arranged in a circular shape.

[0133] By setting the first metal sheet 320 into a circle, there is no need to adjust the assembly direction, so the first metal sheet 320 and the adhesive film 310 can be easily assembled. By setting the adhesive film 310 into a circle, the adhesive film 310 can be assembled in the circular first through hole 101, and when the center of the adhesive film 310 is collinear with the center of the first through hole 101, the fitting surface of the adhesive film 310 and the shell 100 is evenly distributed, the sealing effect is better, and the installation of the adhesive film 310 is convenient.

[0134] Please refer to Fig. 9 , Fig. 9 This is a schematic diagram of the main structure of the film provided in other embodiments of the present application.

[0135] In some embodiments, the first metal sheet 320 may be arranged in a circular shape, and the adhesive film 310 may also be arranged in a ring shape.

[0136] By configuring the adhesive film 310 to be in a ring shape, pressure relief channels can be formed between the adhesive film 310 and the housing 100 and between the adhesive film 310 and the first metal sheet 320 , thereby increasing the number of pressure relief channels and achieving a better pressure relief effect.

[0137] Re-reference Figure 4 and Figure 5 In some embodiments, the first through hole 101 is circular, the diameter of the first metal sheet 320 is less than or equal to the outer diameter of the adhesive film 310 , and the diameter of the first metal sheet 320 is greater than the diameter of the first through hole 101 .

[0138] By setting the diameter of the first metal sheet 320 to be less than or equal to the outer diameter of the adhesive film 310, the assembly of the first metal sheet 320 and the adhesive film 310 can be further facilitated. By setting the diameter of the first metal sheet 320 to be larger than the diameter of the first through hole 101, the first metal sheet 320 can completely cover the first through hole 101, thereby achieving better sealing effect and better shielding effect against water vapor.

[0139] Please refer to Fig.10 , Fig.10 Schematic diagram of the explosion structure of a battery cell provided in some embodiments of the present application.

[0140] In some embodiments, the second metal sheet 330 is disposed between the adhesive film 310 and the housing 100 , the second metal sheet 330 is welded to the housing 100 , and the second metal sheet 330 is provided with a first hole 331 .

[0141] Since the first through hole 101 is reused as the injection hole, there may be residual electrolyte at the injection hole of the battery cell 10 after the injection is completed. The electrolyte will affect the viscosity of the adhesive film 310, making the adhesive film 310 and the shell 100 not firmly attached. By setting a second metal sheet 330 for welding with the shell 100, the connection between the pressure relief mechanism 300 and the shell 100 can be made more stable and the sealing effect can be better.

[0142] In some embodiments, the adhesive film 310 may be firstly attached to the first metal sheet 320 and the second metal sheet 330 respectively to form the pressure relief mechanism 300 , and then the pressure relief mechanism 300 may be welded to the housing 100 , which can make the manufacturing process simpler.

[0143] In other embodiments, the first metal sheet 320, the adhesive film 310, and the second metal sheet 330 may be stacked first, and then when the second metal sheet 330 is welded to the shell 100, the welding high temperature may melt the adhesive film 310 to simultaneously achieve the bonding of the adhesive film 310 with the first metal sheet 320 and the second metal sheet 330.

[0144] In some embodiments, the second metal sheet 330 is arranged in a ring shape.

[0145] By configuring the second metal sheet 330 to be ring-shaped, a pressure relief channel with a larger area can be formed in the second metal sheet 330 , thereby achieving a better pressure relief effect.

[0146] Please refer to Fig.11 and Fig.12 , Fig.11 A schematic diagram of a three-dimensional structure of a battery cell provided in some embodiments of the present application. Fig.12 Schematic diagram of the explosion structure of a battery cell provided in some embodiments of the present application.

[0147] The embodiment of the present application provides a battery cell 10, which includes a shell 100, a pole 400 and a pressure relief mechanism 300. The shell 100 includes a bottom wall 110 and multiple side walls surrounding the bottom wall 110. The first side wall 121 of the multiple side walls is provided with a first through hole 101 and a second through hole 102. The pressure relief mechanism covers the first through hole 101, and the pole 400 is passed through the second through hole 102. The pressure relief mechanism includes a film 310, which can melt when the temperature of the battery cell 10 reaches a threshold value, so that the pressure inside the shell 100 can be released through the first through hole 101.

[0148] By providing a pressure relief mechanism including a film 310 to cover the first through hole 101 of the shell 100, the film 310 can melt when the temperature of the battery cell 10 reaches a threshold value to release the pressure inside the shell 100 through the first through hole 101. The pressure relief mechanism has good thermal sensitivity, so that the reliability of pressure relief is high, which can improve the safety of the battery cell 10. In addition, the first through hole 101 and the second through hole 102 for installing the pole 400 are both located on the first side wall 121, so that the pressure relief mechanism can use the space reserved for the pole 400, which can save space for the electrical device equipped with the battery cell 10, make the structure of the electrical device more compact, and reduce the cost of preparing the pressure relief mechanism.

[0149] In some embodiments, the battery cell 10 may further include a first insulating member 410 , which is located on the inner side of the first side wall 121 , connected to the pole 400 , and provided with a channel connecting the internal space of the shell 100 and the pressure relief mechanism.

[0150] By providing a channel connecting the internal space of the shell 100 and the pressure relief mechanism on the first insulating member 410 , the first through hole 101 is not easily blocked during the pressure relief process, the pressure relief effect is better, and the safety of the battery cell pressure relief is higher.

[0151] In some embodiments, the channel is a groove 411 disposed on a side of the first insulating member 410 facing the first sidewall 121 , and at least one end of the groove 411 extends to an edge of the first insulating member 410 .

[0152] By setting the channel in a groove 411 on the side of the first insulating member 410 facing the first side wall 121, the distance between the first through hole 101 and the channel can be shortened, further reducing the possibility of the channel being blocked, improving the pressure relief effect, and increasing the safety of the battery cell pressure relief.

[0153] In some embodiments, the channel penetrates the first insulating member 410 along a width direction of the first insulating member 410 .

[0154] The air on both sides of the first insulating member 410 along the width direction of the first insulating member 410 can flow to the first through hole 101 through the channel, the air flow rate is faster during the pressure relief process, and the pressure relief can still be achieved when the first insulating member 410 is blocked on either side along the width direction of the first insulating member 410, and the reliability of the pressure relief of the battery cell 10 is higher.

[0155] Please refer to Fig.13 , Fig.13 A schematic top view of the structure of a first insulating member provided in some embodiments of the present application.

[0156] In some embodiments, the depth of the groove 411 , ie, the depth of the channel along the opening direction of the first through hole 101 (ie, the thickness direction of the first side wall 121 ) is A, which satisfies: 0.05 mm≤A≤0.5 mm.

[0157] By setting the depth A of the channel along the opening direction of the first through hole 101 to 0.05mm to 0.5mm, the first insulating member 410 can have a larger cross-sectional area of ​​the channel and a faster pressure relief speed without occupying too much space inside the shell 100; if A is smaller (such as less than 0.05mm), the cross-sectional area of ​​the channel is smaller and easily blocked, and the pressure relief speed is too slow, affecting the safety of pressure relief; if A is larger (such as greater than 0.5mm), the size of the first insulating member 410 will be too large, occupying more space inside the shell 100, squeezing the installation space of other components in the shell 100.

[0158] In some embodiments, 0.1 mm≤A≤0.2 mm, which can further increase the cross-sectional area of ​​the channel without occupying too much space inside the housing 100 .

[0159] Please refer to Fig.14 and Fig.15 , Fig.14 This is a schematic diagram of the main structure of the first insulating member provided in some embodiments of the present application, Fig.15 This is a schematic diagram of the main structure of a battery cell provided in some embodiments of the present application.

[0160] In some embodiments, the diameter of the first through hole 101 along the spacing direction between the second through hole 102 and the first through hole 101 is B, and the width of the channel along the spacing direction between the second through hole 102 and the first through hole 101 is C, satisfying: 0.8*B≤C.

[0161] By setting C to be greater than or equal to 0.8*B, the connecting area between the channel and the first through hole 101 is larger and the pressure relief speed is faster; if C is smaller (such as less than 0.8*B), the connecting area between the channel and the first through hole 101 is smaller and easily blocked, and the pressure relief speed is too slow, affecting the safety of pressure relief.

[0162] In some embodiments, B≤C≤2*B, which can further increase the connecting area between the channel and the first through hole 101 .

[0163] Please refer to Fig.11 , Figures 16 to 18 , Fig.16 This is a bottom-up structural diagram of a battery cell provided in some embodiments of the present application. Fig.17 for Fig.16 Schematic diagram of the cross-sectional structure along the X1-X1 direction, Fig.18 for Fig.16Schematic diagram of the cross-sectional structure along the X2-X2 direction.

[0164] In some embodiments, the battery cell 10 also includes an electrode assembly (not shown in the figure) and a adapter 420, which are both arranged in the shell 100. The adapter 420 is used to electrically connect the electrode assembly and the pole 400. The first insulating member 410 is located between the first side wall 121 and the adapter 420. The first insulating member 410 is provided with a third through hole 412, and the adapter 420 is provided with a fourth through hole 631. The pole 400 is penetrated by the third through hole 412 and the fourth through hole 631 and is riveted to the adapter 420.

[0165] By allowing the pole 400 to pass through the first insulating member 410 and the adapter 420 and to be riveted to the adapter 420 , the connection between the pole 400 and the adapter 420 can be made more stable, and the first insulating member 410 can play the role of insulating and isolating the adapter 420 and the housing 100 .

[0166] In some embodiments, the battery cell 10 may further include a second insulating member 430 , at least a portion of which is located outside the first side wall 121 , and the second insulating member 430 is provided with a fifth through hole 431 , and the pole 400 is passed through the fifth through hole 431 .

[0167] By passing the pole 400 through the second insulating member 430 , the second insulating member 430 can play a role in insulating and isolating the pole 400 and the housing 100 .

[0168] Please refer to Fig.19 , Fig.19 A schematic cross-sectional view of a partial structure of a battery cell provided in some embodiments of the present application.

[0169] In some embodiments, the adhesive film 310 may include a first adhesive segment 310 a and a second adhesive segment 310 b connected to each other. The first adhesive segment 310 a is located outside the first sidewall 121 , and at least a portion of the second adhesive segment 310 b is located inside the first through hole 101 .

[0170] By dividing the adhesive film 310 into the first adhesive segment 310a and the second adhesive segment 310b, and at least part of the second adhesive segment 310b is located in the first through hole 101, the first adhesive segment 310a can fit with the housing 100, and the second adhesive segment 310b can block the first through hole 101, thereby achieving a better sealing effect on the first through hole 101.

[0171] Please refer to Fig. 20 , Fig. 20 A schematic cross-sectional view of a partial structure of a battery cell provided in some embodiments of the present application.

[0172] In some embodiments, the adhesive film 310 may also include a first adhesive segment 310a, a second adhesive segment 310b and a third adhesive segment 310c connected in sequence, the first adhesive segment 310a is located on the outside of the first side wall 121, the second adhesive segment 310b is located in the first through hole 101, and the third adhesive segment 310c is located on the inside of the first side wall 121.

[0173] By dividing the adhesive film 310 into three adhesive segments and making the third adhesive segment 310 c located inside the first side wall 121 , the adhesive film 310 can be better fixed on the housing 100 , and the sealing reliability of the first through hole 101 is improved.

[0174] In some embodiments, the dimension of the third adhesive segment 310c along the thickness direction of the bottom wall 110 is greater than the dimension of the second adhesive segment 310b along the thickness direction of the bottom wall 110 , which can further prevent the adhesive film 310 from detaching and improve the sealing reliability of the first through hole 101 .

[0175] In some embodiments, the first through hole 101 is circular, and the diameter of the first through hole 101 is B, satisfying 0.5 mm ≤ B ≤ 3 mm.

[0176] By setting the diameter B of the first through hole 101 to 0.5 mm to 3 mm, the first through hole 101 can provide a pressure relief channel with a larger cross-sectional area when the battery cell 10 is in thermal runaway, and the installation of the pressure relief mechanism 300 is facilitated; if B is smaller (such as less than 0.5 mm), the cross-sectional area of ​​the pressure relief channel formed by the melting of the adhesive film 310 when the battery cell 10 reaches thermal runaway is smaller, and the gas in the shell 100 may not be released in time, and the safety of the pressure relief of the battery cell 10 is lower; if B is larger (such as greater than 3 mm), a larger area of ​​the pressure relief mechanism 300 is required to cover the first through hole 101, making the installation of the pressure relief mechanism 300 difficult.

[0177] In some embodiments, 0.9 mm ≤ B ≤ 1.6 mm, which can further provide a pressure relief channel with a larger cross-sectional area and facilitate the installation of the pressure relief mechanism 300 .

[0178] In some embodiments, the width of the portion where the pressure relief mechanism 300 is in contact with the first side wall 121 is W, satisfying 0.2 mm≤W≤2 mm.

[0179] By setting the width W of the portion where the adhesive film 310 is in contact with the first side wall 121 to be between 0.2 mm and 2 mm, the length of the pressure relief path of the battery cell 10 can be shorter during thermal runaway, and the battery cell 10 can have higher sensitivity to pressure relief. At the same time, the sealing reliability of the adhesive film 310 for the first through hole 101 can be higher. If W is smaller (such as less than 0.2 mm), the sealing reliability of the adhesive film 310 for the first through hole 101 is lower. If W is larger (such as greater than 2 mm), the length of the pressure relief path is longer, and the battery cell 10 can have lower sensitivity to pressure relief.

[0180] In some embodiments, 0.3 mm ≤ W ≤ 1 mm, which can further shorten the length of the pressure relief path of the battery cell 10 during thermal runaway, and increase the sensitivity of the pressure relief of the battery cell 10 .

[0181] Please refer to Figure 1 According to some embodiments of the present application, the embodiments of the present application also provide an electrical device, including the battery cell 10 of any of the above schemes, and the battery cell 10 is used to provide electrical energy to the electrical device.

[0182] The electrical device may be any of the aforementioned devices or equipment using the battery cell 10 .

[0183] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0184] The above are only preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A pressure relief mechanism, characterized in that: The pressure relief mechanism comprises: Adhesive film; A first metal sheet, disposed on one side of the adhesive film and bonded to the adhesive film; The pressure relief mechanism is used for relieving pressure in the battery cell, and the adhesive film can melt when the temperature reaches a threshold value.

2. A pressure relief mechanism according to claim 1, characterized in that: The pressure relief mechanism further includes a second metal sheet, which is arranged on a side of the adhesive film away from the first metal sheet.

3. A pressure relief mechanism according to claim 1, characterized in that: The melting point of the adhesive film is 100°C to 130°C.

4. A pressure relief mechanism according to claim 3, characterized in that: The adhesive film includes a first adhesive layer and a second adhesive layer, the first adhesive layer and the second adhesive layer are stacked, the second adhesive layer is located on a side of the first adhesive layer facing the first metal sheet, and the melting point of the first adhesive layer is lower than the melting point of the second adhesive layer.

5. A pressure relief mechanism according to claim 4, characterized in that: The adhesive film further includes a third adhesive layer, the third adhesive layer is located between the second adhesive layer and the first metal sheet, and the melting point of the third adhesive layer is lower than the melting point of the second adhesive layer.

6. A pressure relief mechanism according to claim 5, characterized in that: The first adhesive layer, the second adhesive layer, and the third adhesive layer satisfy at least one of the following conditions: (1) The melting point of the first adhesive layer is T1, which satisfies 100°C ≤ T1 ≤ 130°C; (2) The melting point of the second adhesive layer is T2, which satisfies 140°C ≤ T2 ≤ 190°C; (3) The melting point of the third adhesive layer is T3, which satisfies 100°C≤T3≤130°C.

7. The pressure relief mechanism according to claim 1, characterized in that: The thickness of the adhesive film is H, which satisfies 0.05 mm ≤ H ≤ 0.5 mm.

8. The pressure relief mechanism according to claim 7, characterized in that: 0.1mm≤H≤0.3mm.

9. A battery cell, characterized in that: include: The housing comprises a bottom wall and a plurality of side walls surrounding the bottom wall, wherein a first side wall of the plurality of side walls is provided with a first through hole and a second through hole; A pressure relief mechanism, arranged to cover the first through hole, wherein the pressure relief mechanism is the pressure relief mechanism according to any one of claims 1 to 8; A pole, passing through the second through hole; The adhesive film can melt when the temperature of the battery core reaches a threshold value, so that the pressure inside the shell can be released through the first through hole.

10. The battery cell according to claim 9, characterized in that: The battery core further includes a first insulating member, which is located on the inner side of the first side wall, connected to the pole, and provided with a channel connecting the inner space of the shell and the pressure relief mechanism.

11. The battery cell according to claim 10, characterized in that: The channel is a groove provided on a side of the first insulating member facing the first side wall, and at least one end of the groove extends to an edge of the first insulating member.

12. The battery cell according to claim 11, characterized in that: The groove penetrates the first insulating member along a width direction of the first insulating member.

13. The battery cell according to claim 11, characterized in that: The depth of the groove is A, which satisfies: 0.05mm≤A≤0.5mm.

14. The battery cell according to claim 13, characterized in that: 0.1mm≤A≤0.2mm.

15. The battery cell according to claim 11, characterized in that: The diameter of the first through hole is B, and the width of the groove is C, satisfying: 0.8*B≤C.

16. The battery cell according to claim 15, characterized in that: B≤C≤2*B.

17. The battery cell according to claim 10, characterized in that: The battery cell further includes an electrode assembly and a transition piece, wherein the electrode assembly and the transition piece are both disposed in the housing, the transition piece is used to electrically connect the electrode assembly and the pole, and the first insulating piece is located between the first side wall and the transition piece; The first insulating member is provided with a third through hole, the adapter is provided with a fourth through hole, the pole is passed through the third through hole and the fourth through hole and is riveted to the adapter.

18. The battery cell according to claim 17, characterized in that: The battery core further includes a second insulating member, at least a portion of which is located outside the first side wall, and the second insulating member is provided with a fifth through hole, and the pole is passed through the fifth through hole.

19. The battery cell according to claim 9, characterized in that: The adhesive film includes a first adhesive segment and a second adhesive segment that are connected, the first adhesive segment is located outside the first side wall, and at least a portion of the second adhesive segment is located in the first through hole.

20. The battery cell according to claim 19, characterized in that: The adhesive film further includes a third adhesive segment connected to a side of the second adhesive segment away from the first adhesive segment, and the third adhesive segment is located on an inner side of the first side wall.

21. The battery cell according to claim 9, characterized in that: The first through hole is circular, and the diameter of the first through hole is B, satisfying 0.5 mm ≤ B ≤ 3 mm.

22. The battery cell according to claim 21, characterized in that: 0.9mm≤B≤1.6mm.

23. The battery cell according to claim 9, characterized in that: The width of the portion where the adhesive film is attached to the first side wall is W, satisfying 0.2 mm≤W≤2 mm.

24. The battery cell according to claim 23, characterized in that: 0.3mm≤W≤1mm.

25. An electrical device, characterized in that: The battery cell comprises a battery cell as described in any one of claims 9 to 24, wherein the battery cell is used to provide electrical energy.

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