Battery cell and electronic equipment

Abstract

The utility model provides a battery cell and electronic equipment. The battery cell comprises a first pole piece, a second pole piece, an annular sealing element and an insulating medium layer, the first pole piece and the second pole piece are stacked and are opposite in polarity, the first pole piece comprises a first current collector, and the second pole piece comprises a second current collector; the annular sealing element is arranged between the first current collector and the second current collector, and the annular sealing element, the first current collector and the second current collector jointly define a closed cavity; the insulating medium layer is arranged in the closed chamber and isolates the first current collector and the second current collector. The airtight chamber can improve the leakproofness of the area, and external substances are prevented from entering the airtight chamber to affect the structure in the airtight chamber. When the battery cell works normally, the first current collector and the second current collector are isolated by the insulating medium layer in the closed chamber; and when the battery cell is in thermal runaway or the safety structure is punctured, the insulating medium layer in the closed chamber changes to prevent the battery from further runaway or explosion, so that the safety performance of the battery in use is improved.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and in particular to a battery cell and electronic equipment. Background Art

[0002] In the field of batteries, battery safety is an issue that needs to be addressed urgently. In addition to using materials with more stable safety performance, new materials and substances are also used to improve battery safety. However, batteries may still experience thermal runaway or battery puncture and other failures. Batteries are prone to further explosions, causing secondary damage and thus causing some safety issues. Utility Model Content

[0003] In view of this, the present application provides a safety structure to solve the safety problem of the battery. The present application also provides a battery including the above safety structure.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] A battery cell, characterized by comprising:

[0006] A first pole piece and a second pole piece, wherein the first pole piece and the second pole piece are stacked and have opposite polarities, the first pole piece includes a first current collector, and the second pole piece includes a second current collector;

[0007] an annular sealing member, disposed between the first current collector and the second current collector, and enclosing together with the first current collector and the second current collector to form a closed chamber;

[0008] The insulating medium layer is disposed in the sealed chamber and isolates the first current collector from the second current collector.

[0009] Optionally, the insulating medium layer includes a heat shrinkable layer.

[0010] Optionally, the insulating dielectric layer further includes:

[0011] Insulation parts;

[0012] A conductive sheet connected to one side of the heat shrinkable layer, wherein the heat shrinkable layer shrinks when the temperature is not lower than 90° C.

[0013] The conductive sheet and the insulating member are stacked, and the conductive sheet is attached to one of the first current collector and the second current collector, and the insulating member is disposed between the other current collector and the conductive sheet.

[0014] Optionally, the insulating medium layer is a fluid layer, and the fluid layer includes at least one of a polyol solution, a polyacrylic acid solution, a polyolefin melt, a polyurethane melt, or a gel.

[0015] Optionally, the insulating medium layer includes a flame retardant layer and an insulating layer, the flame retardant layer and the insulating layer are both arranged between the first current collector and the second current collector, and the flame retardant layer is attached to one of the first current collector and the second current collector, and the insulating layer is arranged between the other one and the flame retardant layer.

[0016] Optionally, the flame retardant layer includes NaN3 and NaHCO3, and when the temperature of the flame retardant layer is not lower than 90°C, the flame retardant layer generates an inert gas.

[0017] Optionally, the flame retardant layer is a flame retardant and a first solvent, and the boiling point of the first solvent is t, wherein t satisfies: 90°C≤t≤120°C.

[0018] Optionally, the flame retardant is at least one of polyphosphate, aluminum hydroxide or magnesium hydroxide, and the first solvent is at least one of dimethyl carbonate, ethyl methyl carbonate, petroleum ether or cyclohexane.

[0019] Optionally, in the orthographic projection of the plane where the large surface of the battery cell is located, the annular seal extends beyond at least one side edge of the first current collector and / or the second current collector.

[0020] Optionally, the battery core is a winding core, the winding core comprises a straight section and an arc section, and the annular seal and the insulating medium layer are arranged in the arc section; or

[0021] The annular seal and the insulating medium layer are arranged in the straight section.

[0022] Optionally, the annular seal comprises:

[0023] A base layer, wherein the thickness of the base layer is 5 to 20 μm, and the base layer is a PET layer, a PE layer or a PP layer;

[0024] The adhesive layer is arranged on both sides of the base layer, the thickness of the adhesive layer is 1 to 20 μm, and the adhesive layer is at least one of an acrylate layer, an epoxy resin layer, a polyurethane layer, a polyester layer, an EVA hot melt adhesive layer, a styrene block copolymer layer, a polyamide layer, a polyurethane layer or a polyolefin layer.

[0025] An electronic device, comprising any one of the above-mentioned battery cells, the electronic device comprising a housing, the battery cell being installed in the housing;

[0026] The annular seal and the insulating medium layer are arranged on a side of the battery core close to the shell.

[0027] The safety structure provided by the present application is achieved by providing an annular seal between the first current collector and the second current collector of the battery cell, and forming a closed chamber with the first current collector and the second current collector, and providing an insulating medium layer isolating the first current collector and the second current collector in the inner wall chamber. The closed chamber can improve the airtightness of the area and prevent foreign substances from entering the closed chamber and affecting the structure in the closed chamber. When the battery cell is working normally, the insulating medium layer in the closed chamber isolates the first current collector and the second current collector, and the battery cell discharges normally; when the battery cell thermally runs away or the safety structure is punctured, the insulating medium layer in the closed chamber changes, preventing the battery from further losing control or exploding, thereby improving the safety performance of the battery when in use. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0029] Figure 1 A front view of the winding core structure is provided for this embodiment;

[0030] Figure 2 It is a front view of the stacked core structure;

[0031] Figure 3 It is a three-dimensional picture of the closed chamber;

[0032] Figure 4 is a top view of the annular seal;

[0033] Figure 5 A top view of a sealed chamber hiding a first current collector in one embodiment;

[0034] Figure 6 for Figure 5 Sectional view at AA;

[0035] Figure 7 A top view of another embodiment in which a sealed chamber hides a first current collector;

[0036] Figure 8 for Figure 7 Sectional view at the middle BB;

[0037] Fig. 9 A top view of a sealed chamber hiding a first current collector in another embodiment;

[0038] Fig.10 for Fig. 9 Cross-section view at CC.

[0039] Figures 1 to 10 middle:

[0040] 1-first pole piece, 2-second pole piece, 3-annular seal, 4-insulating medium layer, 5-straight section, 6-arc section;

[0041] 11 - first current collector, 21 - second current collector, 41 - heat shrinkable layer, 42 - insulating member, 43 - conductive sheet, 44 - fluid layer, 45 - flame retardant layer, 46 - insulating layer. DETAILED DESCRIPTION

[0042] The present application provides a battery cell. The present application also provides an electronic device including the battery cell.

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] like Figures 1 to 10 As shown, the embodiment of the present application provides a battery cell, which can be combined with a shell and components to form a battery, and the battery is installed on an electrical device and provides power to the electronic device. The battery cell mainly includes a first pole piece 1, a second pole piece 2, an annular seal 3 and an insulating medium layer 4. The first pole piece 1 and the second pole piece 2 are stacked and have opposite polarities. The first pole piece 1 includes a first current collector 11, and the second pole piece 2 includes a second current collector 21; the annular seal 3 is arranged between the first current collector 11 and the second current collector 21, and together with the first current collector 11 and the second current collector 21, forms a closed chamber; the insulating medium layer 4 is arranged in the closed chamber, and isolates the first current collector 11 and the second current collector 21. Specifically, an annular seal 3 is provided between the first current collector 11 and the second current collector 21, and the annular seal 3 and the first current collector 11 and the second current collector 21 are enclosed together to form a closed chamber, which can improve the airtightness of the area, prevent foreign substances from entering the closed chamber and affecting the structure in the closed chamber, and the insulating medium layer 4 in the closed chamber can change with the temperature or puncture state outside the closed chamber to improve the safety of the battery cell. The insulating medium layer 4 is provided between the first current collector 11 and the second current collector 21 in the closed chamber to isolate the first current collector 11 and the second current collector 21. Thus, when the battery cell is working normally, the insulating medium layer 4 in the closed chamber isolates the first current collector 11 and the second current collector 21, and the battery cell discharges normally; when the battery cell is thermally out of control or the safety structure is punctured, the insulating medium layer 4 in the closed chamber changes, preventing the battery from further losing control or exploding, thereby improving the safety performance of the battery when in use.

[0045] It should be noted that the closed chamber refers to the area jointly enclosed by the annular seal 3, the first current collector 11 and the second current collector 21. The annular seal 3 is arranged between the first current collector 11 and the second current collector 21, usually located at the end of the battery cell (the end in the stacking direction of the stacked core or the tail of the winding core). The annular seal 3 forms the side wall of the closed chamber, and the first current collector 11 and the second current collector 21 located on both sides of the annular seal 3 form the upper and lower walls of the closed chamber.

[0046] It should also be noted that the closed chamber does not only refer to the closed and airtight space formed by the annular seal 3 and the first current collector 11 and the second current collector 21. The closed chamber may have inevitable gaps. The closed chamber refers to a closed space formed by at least the seal and the first current collector 11 and the second current collector 21.

[0047] Here, the first current collector 11 and the second current collector 21 are not limited. The first current collector 11 can be a negative electrode current collector of copper foil, and correspondingly, the second current collector 21 can be a positive electrode current collector of aluminum foil; the first current collector 11 can be a positive electrode current collector of aluminum foil, and correspondingly, the second current collector 21 can be a negative electrode current collector of copper foil.

[0048] The battery cell of the above structure is provided with an annular seal 3 between the first current collector 11 and the second current collector 21 of the battery cell, and a closed chamber is formed with the first current collector 11 and the second current collector 21, and an insulating medium layer 4 is provided in the inner wall chamber to isolate the first current collector 11 and the second current collector 21. The closed chamber can improve the airtightness of the area and prevent foreign substances from entering the closed chamber and affecting the structure in the closed chamber. When the battery cell works normally, the insulating medium layer 4 in the closed chamber isolates the first current collector 11 and the second current collector 21, and the battery cell discharges normally; when the battery cell thermally runs away or the safety structure is punctured, the insulating medium layer 4 in the closed chamber changes, preventing the battery from further losing control or exploding, thereby improving the safety performance of the battery during use.

[0049] In some embodiments, the insulating medium layer 4 includes a heat shrink layer 41. Specifically, when the battery provided with the cell is used under high loads such as high power and high current, or when the battery is in a relatively harsh environment such as high temperature, impact, and foreign body extrusion, such as when the battery is continuously in an ambient temperature above 90°C during use, or when the battery is squeezed and impacted by foreign objects, causing the battery temperature to continue to rise. At this time, the heat shrink layer 41 in the closed chamber shrinks, thereby reducing the size of the insulating medium layer 4, so that the first current collector 11 and the second current collector 21 are in contact, so that the first current collector 11 and the second current collector 21 are short-circuited, the cell is discharged slowly, the battery energy is reduced, and the consequences of combustion and explosion caused by thermal runaway of the battery are avoided. Moreover, when the temperature is low and the battery is used normally, the heat shrink layer 41 of the insulating medium layer 4 does not shrink, the first current collector 11 and the second current collector 21 do not contact, and the battery performs normal charging and discharging.

[0050] In some embodiments, the insulating medium layer 4 further includes an insulating member 42 and a conductive sheet 43, the conductive sheet 43 is connected to one side of the heat shrink layer 41, and the heat shrink layer 41 shrinks when the temperature is not lower than 90°C; and the conductive sheet 43 and the insulating member 42 are stacked, and the conductive sheet 43 is attached to one of the first current collector 11 and the second current collector 21, and the insulating member 42 is arranged between the other and the conductive sheet 43. Specifically, when the battery provided with the battery cell has the above-mentioned fault and the battery cell temperature is high, the heat shrink layer 41 shrinks, and the size of the heat shrink layer 41 becomes smaller, and the heat shrink layer 41 drives the conductive sheet 43 to move to a position where the insulating member 42 is not provided, so that the first current collector 11 and the second current collector 21 are in contact through the conductive sheet 43, so as to achieve short circuit between the first current collector 11 and the second current collector 21, so that the battery cell is discharged slowly, the battery energy is reduced, and the consequences such as combustion and explosion caused by thermal runaway of the battery are avoided. With such a configuration, when the heat shrink layer 41 shrinks, the conductive sheet 43 can accelerate the short circuit between the first current collector 11 and the second current collector 21, quickly realize the short circuit between the first current collector 11 and the second current collector 21, and avoid further thermal runaway of the battery cell. Moreover, when the temperature is low and the battery is used normally, the heat shrink layer 41 of the dielectric layer of the insulating member 42 does not shrink, the insulating member 42 is arranged between the conductive sheet 43 and another current collector, the first current collector 11 and the second current collector 21 are not in contact with the conductive sheet 43, and the battery provided with the battery cell performs normal charging and discharging operations.

[0051] In some embodiments, the insulating medium layer 4 is a fluid layer 44. Specifically, when the battery provided with the cell is subjected to mechanical compression such as heavy impact, screw compression or needle puncture, the sealed chamber will be punctured, and the insulating medium layer 4, which is the fluid layer 44, will flow out from the punctured position. After the fluid flows out, the first current collector 11 and the second current collector 21 located on both sides of the fluid layer 44 will be short-circuited, and the battery voltage and energy will decrease rapidly, thereby preventing the battery from thermal runaway; at the same time, the fluid is an insulating fluid, and when it flows down, it will synchronously cover the fracture surface layer of the battery pole piece, effectively reducing the risk of secondary fire when the pole piece is exposed to the air, thereby improving the safety of the battery provided with the cell when in use.

[0052] Exemplarily, the fluid layer 44 includes at least one of a polyol solution, a polyacrylic acid solution, a polyolefin melt, a polyurethane melt, or a gel.

[0053] In some embodiments, the insulating medium layer 4 includes a flame retardant layer 45 and an insulating layer 46, and the flame retardant layer 45 and the insulating layer 46 are both arranged between the first current collector 11 and the second current collector 21, and the flame retardant layer 45 is attached to one of the first current collector 11 and the second current collector 21, and the insulating layer 46 is arranged between the other and the flame retardant layer 45. Specifically, when the battery provided with the battery cell has the above-mentioned fault and causes the battery cell temperature to be high, the volume of the flame retardant layer 45 in the closed chamber becomes larger, so that the flame retardant layer 45 will rush out of the closed chamber, and the flame retardant material in the flame retardant layer 45 will flow to the high temperature area of ​​the battery cell to prevent the battery cell from burning due to excessive temperature, so as to achieve a flame retardant effect. Moreover, when the battery cell is working normally, an insulating layer 46 is arranged between the first current collector 11 and the second current collector 21, and the insulating layer 46 can prevent the first current collector 11 and the second current collector 21 from short-circuiting in the chamber, thereby ensuring the normal operation of the battery cell.

[0054] In this embodiment, an optional implementation is provided, the flame retardant layer 45 includes NaN3 and NaHCO3, and when the temperature of the flame retardant layer 45 is not less than 90°C, the flame retardant layer 45 generates an inert gas. Specifically, the flame retardant layer 45 is set to a NaN3 solution or a NaHCO3 solution, so that when the temperature of the battery core rises to about 90°C, NaN3 will be thermally decomposed into nitrogen, so that the pressure in the closed chamber will increase, and the nitrogen will break through the edge of the closed chamber. Nitrogen is an inert gas that can play a flame retardant role and can prevent the battery core from burning due to further increase in temperature. Correspondingly, the flame retardant layer 45 can also be a NaHCO3 solution, so that when the temperature of the battery core rises to about 90°C, NaHCO3 will be thermally decomposed into carbon dioxide gas, so that the pressure in the closed chamber will increase, and the carbon dioxide gas will break through the edge of the closed chamber. Carbon dioxide gas is also an inert gas that can play a flame retardant role, which can prevent the battery core from burning due to further increase in temperature, thereby improving the safety performance of the battery core.

[0055] In this embodiment, another optional implementation is also provided, the flame retardant layer 45 is a flame retardant and a first solvent, and the boiling point of the first solvent is t, where t satisfies: 90°C≤t≤120°C. Specifically, the flame retardant layer 45 is set to be a flame retardant and a first solvent, so that when the temperature of the battery cell rises to about 90°C to 120°C, the first solvent with a low boiling point between 90°C and 120°C will boil, which will cause the pressure in the closed chamber to increase, so that the flame retardant will rush out of the edge of the closed chamber, and the flame retardant with flame retardant effect will flow to various positions of the battery cell to play a flame retardant role, prevent the battery cell from being heated and burned, and improve the safety performance of the battery cell.

[0056] Exemplarily, the flame retardant is at least one of polyphosphate, aluminum hydroxide or magnesium hydroxide. When the polyphosphate, aluminum hydroxide or magnesium hydroxide flows out of the sealed chamber and flows to other positions of the battery cell, it can have a flame retardant effect.

[0057] Exemplarily, the first solvent is at least one of dimethyl carbonate, ethyl methyl carbonate, petroleum ether or cyclohexane. Specifically, the first solvent is set to the above-mentioned low boiling point solvent. When the temperature of the battery cell rises, the above-mentioned dimethyl carbonate, ethyl methyl carbonate, petroleum ether or cyclohexane will boil and produce gas, which will cause the pressure in the closed chamber to increase, so that the flame retardant will rush out of the edge of the closed chamber to achieve the effect of releasing the flame retardant.

[0058] In some embodiments, in the orthographic projection of the plane where the large surface of the battery cell is located, the annular seal 3 exceeds at least one side edge of the first current collector 11 and / or the second current collector 21. When the battery cell is a roll core, the large surface of the battery cell refers to the plane where the outermost straight section 5 of the roll core is located; when the battery cell is a stacked core, the large surface of the battery cell refers to the end face in the stacking direction of the stacked core. Specifically, the annular seal 3 exceeds one side edge or both side edges of the first current collector 11, and / or the annular seal 3 exceeds one side edge or both side edges of the second current collector 21, which can ensure the stability of the bonding between the annular seal 3 and the first current collector 11 and the second current collector 22, improve the stability of the closed chamber, avoid further occurrence of thermal runaway, and improve the safety of the battery cell when in use.

[0059] In some embodiments, the battery cell is a winding core, and the winding core includes a straight section 5 and an arc section 6, and the annular seal 3 and the insulating medium layer 4 are arranged in the arc section 6; or, the annular seal 3 and the insulating medium layer 4 are arranged in the straight section 5. Specifically, when the battery cell is a winding core, the annular seal 3 and the insulating medium layer 4 can be arranged in the straight section 5, or the annular seal 3 and the insulating medium layer 4 can be arranged in the arc section 6, so that when the battery provided with the battery cell is subjected to mechanical compression such as heavy impact, screw extrusion or acupuncture, the closed chamber is broken, and the insulating medium layer 4 of the fluid layer 44 flows out, and then the first current collector 11 and the second current collector 21 are in contact and short-circuited, so as to prevent the battery from continuing to react and causing thermal runaway. Since the volume occupied by the straight section 5 in the winding core is greater than the volume occupied by the arc section 6, it is preferred to arrange the annular seal 3 and the insulating medium layer 4 in the straight section 5, which can further improve the safety of the battery cell.

[0060] In some embodiments, the annular seal 3 includes a base layer and an adhesive layer. The thickness of the base layer is 5 to 20 μm; the adhesive layer is disposed on both sides of the base layer, and the thickness of the adhesive layer is 1 to 20 μm. Specifically, ensuring that the thickness of the adhesive layer and the base layer is within the above range can ensure the bonding strength between the annular seal 3 and the first current collector 11 and the second current collector 21.

[0061] It should be noted that the base layer is a PET layer, a PE layer or a PP layer; the adhesive layer is at least one of an acrylate layer, an epoxy resin layer, a polyurethane layer, a polyester layer, an EVA hot melt adhesive layer, a styrene block copolymer layer, a polyamide layer, a polyurethane layer or a polyolefin layer.

[0062] Exemplarily, the thickness of the base layer may be 5 μm, 6 μm, 7 μm, 8 μm, 10 μm, 15 μm, or 20 μm; the thickness of the adhesive layer may be 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, 10 μm, 15 μm, or 20 μm.

[0063] An electronic device includes the above-mentioned battery cell. Since the electronic device includes the battery cell, the beneficial effects of the electronic device brought by the battery cell can be found in the above content and will not be repeated here.

[0064] The electronic device includes a shell, and the battery cell is installed in the shell; the annular seal 3 and the insulating medium layer 4 are arranged on the side of the battery cell close to the shell. Specifically, after the battery cell is installed in the shell of the electronic device, one side of the battery cell is the shell of the electronic device, and the other side of the battery cell is the screen of the electronic device. When the electronic device is subjected to mechanical extrusion such as heavy impact, screw extrusion or needle puncture, the side where the screen of the electronic device is located has a larger hardness and is not easy to be broken, while the shell of the electronic device has a smaller hardness and is easy to be broken. Therefore, by arranging the annular seal 3 and the insulating medium layer 4 on the side of the battery cell close to the shell, when the shell side is broken, it can act on the closed chamber formed by the annular seal 3, the insulating medium layer 4, the first current collector 11 and the second current collector 21 at the first time, and the closed chamber reacts, which can prevent the battery cell from further thermal runaway and improve the safety of the battery cell.

[0065] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0066] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0067] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0068] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0069] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0070] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A battery cell, characterized in that: include: A first pole piece and a second pole piece, wherein the first pole piece and the second pole piece are stacked and have opposite polarities, the first pole piece includes a first current collector, and the second pole piece includes a second current collector; an annular sealing member, disposed between the first current collector and the second current collector, and enclosing together with the first current collector and the second current collector to form a closed chamber; The insulating medium layer is disposed in the sealed chamber and isolates the first current collector from the second current collector.

2. The battery cell according to claim 1, characterized in that: The insulating medium layer includes a heat shrinkable layer.

3. The battery cell according to claim 2, characterized in that: The insulating dielectric layer also includes: Insulation parts; A conductive sheet connected to one side of the heat shrinkable layer, wherein the heat shrinkable layer shrinks when the temperature is not lower than 90° C. The conductive sheet and the insulating member are stacked, and the conductive sheet is attached to one of the first current collector and the second current collector, and the insulating member is disposed between the other current collector and the conductive sheet.

4. The battery cell according to claim 1, characterized in that: The insulating medium layer is a fluid layer, and the fluid layer includes at least one of a polyol solution, a polyacrylic acid solution, a polyolefin melt, a polyurethane melt, or a gel.

5. The battery cell according to claim 1, characterized in that: The insulating medium layer includes a flame retardant layer and an insulating layer, the flame retardant layer and the insulating layer are both arranged between the first current collector and the second current collector, and the flame retardant layer is attached to one of the first current collector and the second current collector, and the insulating layer is arranged between the other one and the flame retardant layer.

6. The battery cell according to claim 5, characterized in that: The flame retardant layer includes NaN3 and NaHCO3, and when the temperature of the flame retardant layer is not lower than 90°C, the flame retardant layer generates an inert gas.

7. The battery cell according to claim 5, characterized in that: The flame retardant layer comprises a flame retardant and a first solvent, and the boiling point of the first solvent is t, wherein t satisfies: 90°C≤t≤120°C.

8. The battery cell according to claim 7, characterized in that: The flame retardant is at least one of polyphosphate, aluminum hydroxide or magnesium hydroxide, and the first solvent is at least one of dimethyl carbonate, ethyl methyl carbonate, petroleum ether or cyclohexane.

9. The battery cell according to claim 1, characterized in that: In the orthographic projection of the plane where the large surface of the battery cell is located, the annular seal extends beyond at least one side edge of the first current collector and / or the second current collector.

10. The battery cell according to claim 1, characterized in that: The battery core is a winding core, the winding core comprises a straight section and an arc section, the annular seal and the insulating medium layer are arranged in the arc section; or The annular seal and the insulating medium layer are arranged in the straight section.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The annular seal comprises: A base layer, wherein the thickness of the base layer is 5 to 20 μm, and the base layer is a PET layer, a PE layer or a PP layer; The adhesive layer is arranged on both sides of the base layer, the thickness of the adhesive layer is 1 to 20 μm, and the adhesive layer is at least one of an acrylate layer, an epoxy resin layer, a polyurethane layer, a polyester layer, an EVA hot melt adhesive layer, a styrene block copolymer layer, a polyamide layer, a polyurethane layer or a polyolefin layer.

12. An electronic device, characterized in that: The electronic device comprises a battery cell as claimed in any one of claims 1 to 11, wherein the battery cell is installed in the housing; The annular seal and the insulating medium layer are arranged on a side of the battery core close to the shell.

Images