Battery cell, battery module and electronic equipment

Abstract

The embodiment of the invention provides a battery cell, a battery module and electronic equipment, and relates to the technical field of batteries. The battery cell comprises a shell, a pole core, a first insulating layer and a second insulating layer, a containing cavity is defined by the shell. The pole core is arranged in the accommodating cavity; the pole core comprises positive plates, negative plates and diaphragms, and the positive plates, the diaphragms and the negative plates are sequentially arranged at intervals. The first insulating layer is arranged around the pole core and located between the inner wall of the shell and the pole core. The second insulating layer is positioned between the inner wall of the shell and the pole core; the maximum tolerable temperature of the second insulating layer is greater than or equal to 300 DEG C. According to the structural design of the battery cell, the probability of thermal runaway of the battery cell can be effectively reduced, so that the stability and the safety of the battery module are improved.

Description

Technical Field

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

[0002] With the development of the new energy industry, especially the power battery industry, the safety of power batteries has become more and more concerned by everyone. At present, the safety accidents of power batteries are mainly caused by thermal runaway of the battery cells in the battery pack. When individual battery cells are in thermal runaway, the high-temperature and high-pressure gas generated will be directly sprayed to the surroundings, which can easily lead to thermal runaway of a large area of ​​the battery pack and cause serious safety accidents.

[0003] Therefore, how to avoid large-scale thermal runaway of the battery pack remains a problem that needs to be solved urgently. Summary of the invention

[0004] The embodiments of the present application provide a battery cell, a battery module and an electronic device, the purpose of which is to reduce the probability of thermal runaway of the battery cell, thereby improving the stability and safety of the battery module.

[0005] To achieve the above objectives, the embodiments of the present application adopt the following technical solutions:

[0006] In a first aspect, a battery cell is provided, which includes a shell, a pole core, a first insulating layer, and a second insulating layer. The shell is surrounded to form a receiving cavity. The pole core is arranged in the receiving cavity; the pole core includes a positive electrode sheet, a negative electrode sheet, and a diaphragm, the positive electrode sheet and the negative electrode sheet have a facing area, and at least a diaphragm is provided between the positive electrode sheet and the negative electrode sheet. The first insulating layer is arranged around the pole core and is located between the inner wall of the shell and the pole core. The second insulating layer is located between the inner wall of the shell and the pole core; the maximum tolerance temperature of the second insulating layer is greater than or equal to 300°C.

[0007] In the embodiments provided in the present application, a second insulating layer having high temperature resistance (maximum tolerable temperature greater than or equal to 300°C) and insulation properties is provided between the inner wall of the outer shell and the pole core, so that electrical insulation can be maintained between the outer shell and the pole core in a high temperature environment, thereby avoiding problems such as the outer shell being charged and arcing inside the battery cell, which may lead to thermal runaway of the battery cell or even the entire electronic device, thereby improving the stability and safety of the battery cell.

[0008] In a possible implementation of the first aspect, the second insulating layer is attached to the inner wall of the shell and is disposed between the inner wall of the shell and the first insulating layer. This can avoid damage to the structure of the pole core during the process of preparing the second insulating layer, thereby improving the product yield of the battery core. In addition, the second insulating layer is disposed between the first insulating layer and the shell, which can effectively isolate the heat from the shell to the first insulating layer, thereby improving the electrical insulation capacity of the first insulating layer in a high temperature environment, and further improving the stability of the battery core.

[0009] In a possible implementation of the first aspect, the second insulating layer is attached to the surface of the pole core, which can reduce the difficulty of preparing the second insulating layer, ensure the bonding firmness of the second insulating layer, and thus improve the stability of the battery cell.

[0010] In a possible implementation of the first aspect, the negative electrode sheet includes a first sub-section and a second sub-section, the first sub-section, the diaphragm and the positive electrode sheet are arranged alternately in sequence, the second sub-section is the portion of the negative electrode sheet that exceeds the end of the positive electrode sheet, and the second sub-section is arranged around the outermost layer of the electrode core, and the second insulating layer is arranged on the second sub-section.

[0011] In a possible implementation of the first aspect, the second insulating layer is disposed on the second sub-part specifically: the second insulating layer is disposed on the negative electrode active layer on the surface of the second sub-part away from the positive electrode sheet. This embodiment can simplify the steps of preparing the electrode core.

[0012] In a possible implementation of the first aspect, the second insulating layer is disposed on the second sub-unit in the following manner: the second insulating layer is disposed on the negative current collector of the second sub-unit instead of the negative active layer on the surface of the side of the second sub-unit away from the positive electrode sheet. Thus, while ensuring the function of the pole core, the size of the pole core can be avoided from being increased after the second insulating layer is disposed, thereby facilitating the miniaturization design of the battery core and avoiding affecting the energy density of the battery core.

[0013] In a possible implementation of the first aspect, the second insulating layer is disposed on the second sub-section specifically as follows: a receiving groove is provided in the negative electrode active layer on a surface of the second sub-section away from the positive electrode sheet; and the second insulating layer is disposed in the receiving groove.

[0014] That is, the negative electrode active layer is removed only at the position where the second insulating layer is set. This can also ensure the function of the pole core while avoiding increasing the size of the pole core after setting the second insulating layer, thereby facilitating the miniaturization design of the battery cell and avoiding affecting the energy density of the battery cell.

[0015] In a possible implementation of the first aspect, the second insulating layer is arranged around the pole core. That is, the second insulating layer is arranged in a full circle, and the second insulating layer is arranged at all sides of the battery core (including the sides of the battery core with a longer length), thereby further improving the electrical insulation ability of the second insulating layer to the pole core.

[0016] In a possible implementation of the first aspect, the second insulating layer is adjacent to and facing the first side surface of the shell; the first side surface of the shell is a surface of the shell that is used to be adjacent to other battery cells. Because the position where the first insulating layer is prone to melting and deformation (i.e., the position adjacent to other battery cells) is covered by the second insulating layer, when the temperature of the battery cell is too high, causing the first insulating layer adjacent to the first side surface of the battery cell to melt and deform, the second insulating layer can still continue to maintain electrical insulation, thereby avoiding short circuit between the shell and the pole core, thereby improving the safety performance of the battery cell.

[0017] In a possible implementation of the first aspect, the positive electrode sheet, the separator and the negative electrode sheet are stacked; or the positive electrode sheet, the separator and the negative electrode sheet are wound.

[0018] In a possible implementation manner of the first aspect, the material of the second insulating layer includes aerogel; and / or the thickness of the second insulating layer is less than or equal to 300 μm.

[0019] By arranging the material of the second insulating layer to include aerogel, it is possible to ensure that the battery cell has a lighter weight while achieving high-temperature electrical insulation properties.

[0020] In a possible implementation manner of the first aspect, the material of the second insulating layer includes a ceramic material; and / or the thickness of the second insulating layer is less than or equal to 200 μm.

[0021] By setting the material of the second insulating layer 40 to include a ceramic material, it is possible to ensure that the second insulating layer has a thinner thickness while achieving high-temperature electrical insulation characteristics, thereby ensuring a miniaturized design of the battery cell.

[0022] In a second aspect, a battery cell is provided, which includes a shell, a pole core and a second insulating layer. The shell is surrounded to form a receiving cavity. The pole core is arranged in the receiving cavity; the pole core includes a positive electrode sheet, a negative electrode sheet and a diaphragm, and the positive electrode sheet, the diaphragm and the negative electrode sheet are arranged alternately in sequence. The second insulating layer is arranged around the pole core and is located between the inner wall of the shell and the pole core; the maximum tolerance temperature of the second insulating layer is greater than or equal to 300°C.

[0023] By setting a second insulating layer around the pole core, it can be ensured that the battery cell can still maintain electrical insulation in a high temperature environment, avoid short circuit between the outer shell and the pole core, and improve the safety performance of the battery cell. In addition, there is no need to set a first insulating layer in the battery cell with a second insulating layer set in a whole circle. On the one hand, it can simplify the preparation process of the battery cell, and on the other hand, it is easy to reduce the size of the battery cell, realize the miniaturization design of the battery cell, and avoid affecting the energy density of the battery cell.

[0024] In a possible implementation of the second aspect, the second insulating layer is attached to the inner wall of the housing, which can reduce the requirements for the flexibility of the second insulating layer, thereby reducing the difficulty of preparing the battery cell while achieving high-temperature insulation.

[0025] In a third aspect, a battery module is provided, the battery module comprising a battery management system and one or more battery cells. The battery cell is a battery cell provided by any one of the embodiments of the first aspect or the second aspect. The one or more battery cells are electrically connected to the battery management system.

[0026] The technical effects brought about by the battery module in the third aspect can refer to the technical effects brought about by the design of the battery cell in the first aspect or the second aspect, and will not be repeated here.

[0027] In a possible implementation of the third aspect, the plurality of battery cells include at least one pair of two adjacent battery cells. The battery module further includes a third insulating layer, which is at least sandwiched between the two adjacent battery cells; and the thickness of the third insulating layer is less than or equal to 3500 μm.

[0028] By providing a third insulating layer between two adjacent battery cells in the battery module, the heat transfer between the two adjacent battery cells can be isolated, effectively preventing a small-scale thermal runaway in the battery module from spreading to a large-scale thermal runaway, thereby avoiding causing serious safety accidents.

[0029] In addition, in the battery module provided in the embodiment of the present application, while the third insulating layer achieves heat insulation between two adjacent battery cells, the thickness of the third insulating layer can be less than or equal to 3500μm, thereby improving the integration of the battery cells in the battery module, or reducing the size of the battery module in the thickness direction of the third insulating layer, thereby facilitating the miniaturization design of the battery module.

[0030] In a fourth aspect, an electronic device is provided, the electronic device comprising a controller and a battery cell provided by any one of the embodiments of the first aspect, the second aspect or the third aspect, wherein the controller is electrically connected to the battery cell.

[0031] The technical effects brought about by the electronic device in the fourth aspect can refer to the technical effects brought about by the design of the battery cell in the first aspect, the second aspect or the third aspect, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of the structure of a battery module provided in an embodiment of the present application;

[0034] Figure 3 A schematic diagram of the structure of a battery cell provided in an embodiment of the present application;

[0035] Figure 4Another schematic diagram of the structure of the battery cell provided in the embodiment of the present application;

[0036] Figure 5 For along Figure 3 A side view in the A direction;

[0037] Figure 6 For along Figure 3 The side view in the B direction;

[0038] Figure 7 Another schematic diagram of the structure of the battery cell provided in the embodiment of the present application;

[0039] Figure 8 Another schematic diagram of the structure of the battery cell provided in the embodiment of the present application;

[0040] Fig. 9 Another schematic diagram of the structure of the battery cell provided in the embodiment of the present application;

[0041] Fig.10 Another schematic diagram of the structure of the battery cell provided in the embodiment of the present application;

[0042] Fig.11 For along Fig.10 Side view in the C direction;

[0043] Fig.12 Another schematic diagram of the structure of the battery cell provided in the embodiment of the present application;

[0044] Fig.13 A temperature change diagram of a battery cell in a thermal runaway experiment provided in an embodiment of the present application;

[0045] Fig.14 This is a temperature change diagram of a battery cell without a second insulation layer during a thermal runaway experiment. DETAILED DESCRIPTION

[0046] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in some embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments provided by the present application, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present application.

[0047] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0048] Unless the context requires otherwise, throughout the specification and claims, the term "including" is interpreted as an open, inclusive meaning, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "exemplarily" or "some examples" and the like are intended to indicate that specific features, structures, materials or characteristics associated with the embodiment or example are included in at least one embodiment or example of the present application. The schematic representation of the above terms does not necessarily refer to the same embodiment or example. In addition, the specific features, structures, materials or characteristics may be included in any one or more embodiments or examples in any appropriate manner.

[0049] In the following, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "plurality" means two or more.

[0050] When describing some embodiments, the expression "connection" and its derivatives may be used. The term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected or indirectly connected through an intermediate medium. The embodiments disclosed herein are not necessarily limited to the contents of this document.

[0051] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0052] As used herein, "parallel", "perpendicular", and "equal" include the situations described and situations similar to the situations described, and the range of the similar situations is within the acceptable deviation range, wherein the acceptable deviation range is determined by a person of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "parallel" includes absolute parallelism and approximate parallelism, wherein the acceptable deviation range of approximate parallelism may be, for example, a deviation within 5°; "perpendicular" includes absolute perpendicularity and approximate perpendicularity, wherein the acceptable deviation range of approximate perpendicularity may also be, for example, a deviation within 5°. "Equal" includes absolute equality and approximate equality, wherein the acceptable deviation range of approximate equality may be, for example, the difference between the two equalities is less than or equal to 5% of either one.

[0053] Exemplary embodiments are described herein with reference to cross-sectional views and / or plan views that are idealized exemplary drawings. In the drawings, the thickness of layers and regions are exaggerated for clarity. Therefore, variations in shape relative to the drawings due to, for example, manufacturing techniques and / or tolerances are conceivable. Therefore, the exemplary embodiments should not be interpreted as being limited to the shapes of the regions shown herein, but include deviations in shape due to, for example, manufacturing. Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shapes of regions of the device, and are not intended to limit the scope of the exemplary embodiments.

[0054] In addition, the scenarios described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application, and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. A person of ordinary skill in the art can appreciate that, with the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0055] The embodiment of the present application provides an electronic device, which may be, for example, a mobile phone, a tablet computer, a personal digital assistant (PDA), a television, a smart wearable product (e.g., a smart watch, a smart bracelet), a virtual reality (VR) terminal device, an augmented reality (AR) terminal device, a rechargeable small household appliance (e.g., a soymilk machine, a sweeping robot), a drone, a radar, an aerospace equipment, an on-board device, a vehicle, a power system, and other different types of user devices or terminal devices; the electronic device may also be a network device such as a base station. The embodiment of the present application does not impose any special restrictions on the specific form of the electronic device.

[0056] The following uses a vehicle as an example to describe in detail the electronic device provided in the embodiments of the present application.

[0057] Figure 1 A schematic diagram of the structure of an electronic device 1000 provided in an embodiment of the present application.

[0058] like Figure 1 As shown, in some embodiments, the electronic device 1000 includes a battery cell 100 and a controller 200. The controller 200 is electrically connected to the battery cell 100.

[0059] Among them, the battery cell 100 is used to provide electrical energy. The controller 200 is used to control the working conditions of the components of the electronic device 1000 (such as a vehicle). For example, the controller 200 is electrically connected to the battery cell 100 to control the power of the battery cell 100. Exemplarily, the controller 200 can be a vehicle control unit (VCU) or a motor control unit (MCU). The embodiment of the present application does not impose any special restrictions on the specific form of the controller 200.

[0060] For example, in some embodiments, the battery cell 100 is directly integrated into the electronic device 1000. For example, when the electronic device 1000 is a vehicle, the battery cell 100 can be directly integrated into the chassis of the vehicle, thereby improving the integration of the vehicle.

[0061] Or, illustratively, in other embodiments, see Figure 1 The electronic device 1000 may include at least one battery module 2000, and the battery cell 100 is integrated in the battery module 2000. The battery module 2000 may be assembled on a chassis of a vehicle.

[0062] For example, the battery module 2000 can be used as a battery pack or a part of a battery pack. The battery module 2000 can support, fix and protect the battery cell 100.

[0063] The present application also provides a battery module 2000, such as Figure 1 As shown, in some embodiments, the battery module 2000 may include one or more battery cells 100 and a battery management system (BMS) 300 .

[0064] It is understandable that the battery module 2000 can be integrated or assembled in the aforementioned electronic device 1000 .

[0065] For example, see Figure 1 The battery module 2000 may include a plurality of battery cells 100 connected in series and / or in parallel to provide the electronic device 1000 with the required electrical energy.

[0066] The battery management system 300 is a system for monitoring and managing the battery cell 100. For example, the working state (charging and discharging) of the battery cell 100 can be controlled or the battery cell 100 can be protected by collecting and calculating parameters such as voltage, current, temperature, and remaining power. For example, the battery management system 300 can prevent the temperature in the battery cell 100 from exceeding a threshold by reducing the current, thereby protecting the battery cell 100 and reducing the probability of safety problems caused by thermal runaway of the battery cell 100.

[0067] For example, when the battery module 2000 is integrated in the electronic device 1000, the controller 200 in the electronic device 1000 can be electrically connected to the battery module 2000 so as to achieve indirect electrical connection between the controller 200 and the battery cell 100 in the battery module 2000, thereby enabling the controller 200 to control the power of the battery cell 100.

[0068] Exemplarily, the battery module 2000 may also include more structures than the above structures, for example, it may also include a thermal management system and an electrical system, etc., and the present application does not limit this.

[0069] Figure 2 A schematic diagram of the structure of a battery module 2000 provided in an embodiment of the present application.

[0070] In some embodiments, Figure 2 As shown, the battery module 2000 includes a plurality of battery cells 100 , wherein the plurality of battery cells 100 include at least one pair of two battery cells 100 disposed adjacent to each other.

[0071] For example, the battery module 2000 includes Figure 2 The first battery cell 101 and the second battery cell 102 are shown in FIG. Figure 2 The first battery cell 101 and the second battery cell 102 are arranged adjacent to each other.

[0072] See also Figure 2 The battery module 2000 further includes a third insulating layer 50, which is sandwiched between two adjacent battery cells 100. For example, see Figure 2 The third insulating layer 50 is disposed between the first battery cell 101 and the second battery cell 102 .

[0073] It can be understood that the battery module 2000 may include multiple third insulating layers 50, and the third insulating layer 50 can be arranged between each pair of adjacent battery cells 100. The drawings provided in the embodiments of the present application only use the adjacent first battery cell 101 and the second battery cell 102, and a third insulating layer 50 arranged therebetween as an example to illustrate the structure of the battery module 2000, rather than limiting the number of battery cells 100 and the number of third insulating layers 50 in the battery module 2000.

[0074] Exemplarily, the material of the third insulating layer 50 may include a high temperature resistant material.

[0075] Exemplarily, the material of the third insulating layer 50 may include aerogel, or may include ceramic material, such as silicon oxide, aluminum oxide, calcium oxide, potassium oxide, sodium oxide, magnesium oxide, zirconium oxide, titanium dioxide and corresponding binders.

[0076] Exemplarily, the maximum withstanding temperature of the third insulating layer 50 may be greater than or equal to 300° C., for example, 300° C., 500.75° C., 753.5° C. or 1000° C., etc.

[0077] By setting a third insulating layer 50 between two adjacent battery cells 100 (a first battery cell 101 and a second battery cell 102) in the battery module 2000, heat transfer between the two adjacent battery cells 100 can be isolated. For example, in the event of thermal runaway of the first battery cell 101, the third insulating layer 50 can prevent the heat generated after the thermal runaway of the first battery cell 101 from being transferred to the second battery cell 102, thereby preventing the second battery cell 102 from also experiencing thermal runaway under high temperature. This effectively prevents the thermal runaway in a small area in the battery module 2000 from spreading to a large area of ​​thermal runaway, thereby avoiding causing serious safety accidents.

[0078] In some embodiments, Figure 2 As shown, the thickness d of the third insulating layer 50 may be less than or equal to 3500 μm. For example, the thickness d of the third insulating layer 50 may be 1000 μm to 3500 μm, or may be less than or equal to 1000 μm. For example, the thickness d of the third insulating layer 50 may be 3500 μm, 2500 μm, 2000 μm, 1680.5 μm, 1000 μm, or 689.83 μm, etc.

[0079] It should be noted that the aforementioned “thickness d of the third insulating layer 50” may refer to the dimension of the third insulating layer 50 in the direction perpendicular to the first battery cell 101 pointing to the second battery cell 102. For example, the thickness d of the third insulating layer 50 may be equal to the distance between the first battery cell 101 and the second battery cell 102 (the distance between the opposite sides of the first battery cell 101 and the second battery cell 102).

[0080] In the battery module 2000 provided in the embodiment of the present application, the third insulating layer 50 can achieve heat insulation between two adjacent battery cells 100 while the thickness d of the third insulating layer 50 can be less than or equal to 3500 μm, thereby improving the integration of the battery cells 100 in the battery module 2000, or reducing the size of the battery module 2000 in the thickness direction of the third insulating layer 50, thereby facilitating the miniaturization design of the battery module 2000.

[0081] The embodiment of the present application further provides a battery cell 100, Figure 3 A schematic diagram of the structure of a battery cell 100 provided in an embodiment of the present application. Figure 4 Another structural schematic diagram of the battery cell 100 provided in an embodiment of the present application. Figure 5 For along Figure 3 Side view in direction A. Figure 6 For along Figure 3 Side view in direction B.

[0082] For example, the type of the battery cell 100 provided in the embodiment of the present application may include a lithium ion battery or a sodium ion battery, etc. It is understandable that the embodiment of the present application does not limit the specific type of the battery cell 100, and the battery cell 100 may also be any type of battery capable of converting electrical energy and other energies except for lithium ion batteries and sodium ion batteries.

[0083] A lithium-ion battery is a rechargeable battery in which lithium ions can migrate between the positive electrode and the negative electrode. During the charging process, lithium ions migrate from the positive electrode to the negative electrode, and during the discharging process, lithium ions migrate from the negative electrode to the positive electrode.

[0084] Lithium-ion batteries are widely used in products such as energy storage base stations, consumer electronics and electric vehicles due to their high specific energy, long service life, no memory effect, low self-discharge rate and environmental friendliness.

[0085] The following uses a lithium battery as an example to describe in detail the battery cell 100 provided in the embodiment of the present application.

[0086] like Figure 3 to Figure 6 As shown, the battery cell 100 may include a housing 10 , a pole core 20 , a first insulating layer 30 and a second insulating layer 40 .

[0087] Among them, see Figure 3 to Figure 6 The housing 10 is surrounded to form a receiving cavity Q, and the receiving cavity Q is used to carry the pole core 20 and protect the pole core 20 and other structures from external damage.

[0088] It should be noted that in order to avoid blocking some structures of the battery cell 100 (such as the pole core 20 and other structures), Figure 3 Only part of the structure of the housing 10 is shown. It is understood that the housing 10 also includes a Figure 3 The part of the structure shown in , so that the shell 10 surrounds and forms a complete chamber (ie, the accommodating chamber Q).

[0089] Exemplarily, the material of the housing 10 may include a conductive material, such as aluminum alloy, copper alloy, steel, etc., or may also include insulating materials such as plastic or ceramic, which is not limited in the embodiment of the present application.

[0090] For example, see Figure 3 and Figure 4 The housing 10 may be roughly in the shape of a cuboid. It is understandable that the housing 10 may also be in other shapes, such as a cube, a sphere, an ellipsoid, etc., and the present application does not limit this.

[0091] Exemplarily, the shell 10 may further include an opening (not shown in the figure), which is communicated with the accommodating cavity Q, so as to facilitate connecting the structure in the accommodating cavity Q (such as the pole core 20 ) to the outside of the shell 10 .

[0092] See also Figure 3 and Figure 4 The pole core 20 is disposed in the accommodating cavity Q. The pole core 20 includes a positive electrode sheet 21, a negative electrode sheet 22 and a separator 23. Figure 3 or Figure 4 The positive electrode sheet 21, the separator 23 and the negative electrode sheet 22 are arranged alternately in sequence. That is, the three have a positive facing area, and the separator 23 is arranged at least between the positive electrode sheet 21 and the negative electrode sheet 22.

[0093] It is understandable that the battery cell 100 also includes an electrolyte, which is arranged in the accommodating cavity Q, and the aforementioned pole core 20 is immersed in the electrolyte. During the charging and discharging process of the lithium-ion battery (i.e., the battery cell 100), the lithium ions in the electrolyte migrate between the positive electrode sheet 21 and the negative electrode sheet 22 of the pole core 20.

[0094] It is understandable that during the charging and discharging process of the lithium-ion battery (ie, the battery cell 100), as the lithium ions migrate, the size of the pole core 20 will increase or decrease. Figure 3 and Figure 4 A gap is provided between the inner wall of the housing 10 and the pole core 20 to provide space for the size change of the pole core 20, and the electrolyte can be provided in the gap.

[0095] For example, see Figure 3 and Figure 4 The positive electrode sheet 21 may include a positive electrode current collector 211 and a positive electrode active layer 212 . The positive electrode active layer 212 may be wrapped on the surface of the positive electrode current collector 211 .

[0096] The positive electrode current collector 211 may include one or more conductive metal layers. For example, the material of the positive electrode current collector 211 may include aluminum foil, and the material of the positive electrode active layer 212 may include lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, ternary materials or any other material that can be used as a positive electrode.

[0097] For example, see Figure 3 and Figure 4 The negative electrode sheet 22 may include a negative electrode current collector 221 and a negative electrode active layer 222 . The negative electrode active layer 222 may be wrapped around the surface of the negative electrode current collector 221 .

[0098] Among them, the negative electrode current collector 221 may include one or more conductive metal layers, for example, the material of the negative electrode current collector 221 may include copper foil, and the material of the negative electrode active layer 222 may include at least one of a carbon negative electrode material, a tin-based negative electrode material, a lithium-containing transition metal nitride negative electrode material, an alloy negative electrode material or a nanoscale negative electrode material, for example, it may include graphite.

[0099] Exemplarily, the positive electrode sheet 21 and the negative electrode sheet 22 may also include other materials. For example, both may include adhesives, etc. This embodiment of the present application is not limited to this.

[0100] For example, see Figure 3 and Figure 4 The aforementioned electrode core 20 may further include a positive electrode ear 24 and a negative electrode ear 25. The positive electrode ear 24 may be formed by a portion of the positive electrode current collector 211 that is not wrapped by the positive electrode active layer 212, or the positive electrode ear 24 may be formed by a conductive structure electrically connected to the positive electrode current collector 211 (which may be integrally provided with the positive electrode current collector 211). Similarly, the negative electrode ear 25 may be formed by a portion of the negative electrode current collector 221 that is not wrapped by the negative electrode active layer 222, or may be formed by a conductive structure electrically connected to the negative electrode current collector 221 (which may be integrally provided with the negative electrode current collector 221).

[0101] The positive electrode tab 24 and the negative electrode tab 25 can be connected to the outside after passing through the outer shell 10, so that the external structure can apply voltage to the positive electrode sheet 21 and the negative electrode sheet 22. For example, the positive electrode tab 24 and the negative electrode tab 25 can be connected to the outside through the opening of the outer shell 10. For example, see Figure 2The negative electrode tab 25 can be connected to the pole N outside the housing 10, so that external electric energy can be input into the battery cell 100 for storage through the pole N. Or, for example, the positive electrode tab 24 can be externally connected to a metal sheet (not shown) outside the housing 10, so that electric energy can be output to the outside of the battery cell 100 through the metal sheet.

[0102] For example, see Figure 5 The battery cell 100 may further include a positive electrode connecting sheet 24A and a negative electrode connecting sheet 25A. The positive electrode ear 24 may be electrically connected to a conductive structure (e.g., a metal sheet) outside the housing 10 through the positive electrode connecting sheet 24A, and the negative electrode ear 25 may be electrically connected to a conductive structure (e.g., a pole N) outside the housing 10 through the negative electrode connecting sheet 25A.

[0103] Exemplarily, a plurality of positive electrode tabs 24 in the same battery cell 100 may be electrically connected, for example, by a positive electrode connecting sheet 24A, and the same is true for the negative electrode tabs 25 .

[0104] It is understandable that in order to avoid blocking the structure of the pole core 20, Figure 5 and Figure 6 The part of the structure of the housing 10 and the first insulating layer 30 parallel to the paper surface is also not shown. Similarly, in order to avoid blocking, Figure 3 and Figure 6 The positive electrode connecting tab 24A and the negative electrode connecting tab 25A are not shown.

[0105] Understandably, Figure 5 The arrangement of the positive electrode ear 24 and the negative electrode ear 25 is only exemplified and does not limit it. The arrangement positions and external connection methods of the positive electrode ear 24 and the negative electrode ear 25 can be different from Figure 5 shown.

[0106] The aforementioned diaphragm 23 has electronic insulation properties and is used to achieve mechanical isolation between the positive electrode sheet 21 and the negative electrode sheet 22 to avoid direct conduction between the positive electrode sheet 21 and the negative electrode sheet 22. In addition, the diaphragm 23 also has a high ion conductivity, which allows lithium ions and other ions to migrate freely between the positive electrode sheet 21 and the negative electrode sheet 22, thereby realizing the charging and discharging of the battery cell 100.

[0107] Exemplarily, the separator 23 may be a single layer or multiple layers.

[0108] For example, the material of the separator 23 may include a polypropylene material or a polyethylene material having multiple micropores.

[0109] For example, see Figure 3 to Figure 5 The aforementioned pole core 20 is generally in the shape of a sheet or a plate. For example, the entire pole core 20 may be in the shape of a strip.

[0110] For example, Figure 4 As shown, the pole core 20 can be provided in a laminated manner (i.e., a laminated core), for example, see Figure 4 The positive electrode sheet 21, the separator 23 and the negative electrode sheet 22 are stacked in sequence.

[0111] Among them, for example, see Figure 4 In the case where the electrode core 20 is a laminated core, the positive electrode sheet 21, the negative electrode sheet 22 and the separator 23 can all be flat sheet materials, and the positive electrode sheets 21 of different layers are disconnected, and the negative electrode sheets 22 and the separator 23 are similar. Alternatively, for example, the multi-layer positive electrode sheet 21 can be provided in one piece, that is, a whole positive electrode sheet 21 is folded back and forth to form multiple layers, and the negative electrode sheet 22 and the separator 23 are the same.

[0112] Among them, for example, see Figure 4 In the case where the electrode core 20 is a laminated core, the positive electrode sheet 21, the negative electrode sheet 22 and the separator 23 can each be multiple sheets.

[0113] Among them, for example, see Figure 4 In the case where the electrode core 20 is a laminated core, the length of the diaphragm 23 is greater than the length of the positive electrode sheet 21 and greater than the length of the negative electrode sheet 22, thereby ensuring the isolation between the positive electrode sheet 21 and the negative electrode sheet 22 and avoiding the problem of device failure caused by interconnection between the positive electrode sheet 21 and the negative electrode sheet 22 at the side.

[0114] Among them, for example, see Figure 4 In the case where the electrode core 20 is a stacked core, the length of the negative electrode sheet 22 is greater than that of the positive electrode sheet 21. Therefore, after the electrode core 20 is stacked, the side of the positive electrode sheet 21 is retracted relative to the side of the negative electrode sheet 22, thereby effectively protecting the positive electrode sheet 21 made of more precious materials and reducing the probability of loss of the positive electrode sheet 21.

[0115] For example, Figure 3 As shown, the pole core 20 can also be wound (i.e., a winding core), for example, see Figure 3 The positive electrode sheet 21, the separator 23 and the negative electrode sheet 22 are stacked and wound. Figure 3 When the electrode core 20 is a winding core, the positive electrode sheet 21, the negative electrode sheet 22 and the separator 23 are all in the shape of a rolled sheet.

[0116] See also Figure 3 and Figure 4 The first insulating layer 30 is disposed around the pole core 20, and the first insulating layer 30 is located between the inner wall of the shell 10 and the pole core 20. The first insulating layer 30 is used to achieve electrical insulation between the shell 10 and the pole core 20, thereby preventing the conductive structure in the pole core 20 from being short-circuited with the shell 10.

[0117] Exemplarily, the material of the first insulating layer 30 may include polypropylene material, polyethylene material or other suitable high molecular polymers.

[0118] For example, Figure 3 As shown, the first insulating layer 30 can be attached to the inner wall of the shell 10 , that is, the pole core 20 and the electrolyte are contained in the first insulating layer 30 , so that the pole core 20 and the shell 10 are isolated by the first insulating layer 30 .

[0119] Alternatively, illustratively, the first insulating layer 30 may be disposed on the surface of the pole core 20 , and may also isolate the pole core 20 from the housing 10 .

[0120] Exemplarily, the first insulating layer 30 can be provided integrally with the separator 23. For example, the length of the separator 23 is set to be longer than the length of the positive electrode sheet 21 and the negative electrode sheet 22, and the excess length of the separator 23 can be wound around the outer ring of the pole core 20 with a preset number of turns (one or more turns), and the portion of the separator 23 surrounding the pole core 20 can be used as the first insulating layer 30, thereby simplifying the preparation process of the battery cell 100 and increasing the consistency and safety of the structure of the battery cell 100.

[0121] See also Figure 3 , Figure 4 and Figure 5 The second insulating layer 40 is located between the inner wall of the shell 10 and the pole core 20 .

[0122] The maximum tolerable temperature of the second insulating layer 40 is greater than or equal to 300° C. For example, it may be 300° C., 500.75° C., 753.5° C. or 1000° C., etc.

[0123] When only the first insulating layer 30 is provided between the shell 10 and the pole core 20 to achieve electrical insulation between the two, the stability of the battery cell 100 is poor, especially when the operating temperature of the battery cell 100 is high, the battery cell 100 is very likely to have thermal runaway, which poses a great safety hazard. For example, when the operating time is too long, or the ambient temperature is high, or the temperature rises due to thermal runaway of the adjacent battery cell 100, the operating temperature of the battery cell 100 will gradually increase over time (for example, to 200°C to 300°C), and the first insulating layer 30 (melting point is approximately 160°C to 180°C) will melt under the action of high temperature, which is likely to cause the electrical insulation between the shell 10 and the pole core 20 to fail, that is, the two are likely to be short-circuited. In addition, the battery cell 100 will also deform (for example, local expansion, etc.) under the action of high temperature, and the deformation will squeeze the first insulating layer 30, further resulting in the thinning or even removal of the insulating material at some positions between the shell 10 and the pole core 20, so that the shell 10 and the pole core 20 are in electrical contact. The electrical contact between the outer shell 10 and the pole core 20 will cause the outer shell 10 to be charged. For example, when the outer layer of the pole core 20 is the negative electrode sheet 22, the electrical contact between the outer shell 10 and the pole core 20 will cause the outer shell 10 to be negatively charged, which may easily cause a short circuit between the outer shell 10 and other conductive structures and produce an arc. For example, when the outer shell 10 is negatively charged, the positive electrode ear 24 closer to the outer shell 10 is likely to produce an arc with the negatively charged outer shell 10, thereby triggering the combustion of the battery cell 100, and even causing a comprehensive thermal runaway of the electronic device 1000 (i.e., the combustion of the entire battery module 2000 or the entire electronic device 1000), resulting in serious safety accidents and economic losses.

[0124] In the aforementioned embodiment provided in the present application, by providing a second insulating layer 40 having high temperature resistance (maximum tolerance temperature greater than or equal to 300°C) and insulation characteristics between the inner wall of the outer shell 10 and the pole core 20, it can be ensured that in the aforementioned high temperature environment, electrical insulation can still be maintained between the outer shell 10 and the pole core 20, thereby avoiding problems such as the outer shell 10 being charged and arcing inside the battery cell 100, which may lead to a comprehensive thermal runaway of the battery cell 100 or even the entire electronic device 1000, thereby improving the stability and safety of the battery cell 100.

[0125] In addition, the second insulating layer 40 is provided in the embodiment of the present application to improve the thermal insulation capability of a single battery cell 100. Figure 2 ) when thermal runaway occurs, the second insulating layer 40 can also isolate the transfer of heat generated by the faulty battery cell 100 (battery cell 100 experiencing thermal runaway), thereby preventing the heat of the faulty battery cell 100 from damaging the normal battery cell 100, avoiding the occurrence of a comprehensive thermal runaway problem, and improving the safety performance of the battery cell 100 and even the battery module 2000 and even the electronic device 1000.

[0126] Furthermore, when the third insulating layer 50 is disposed between adjacent battery cells 100 (see Figure 2 ), by providing the second insulating layer 40, the single battery cell 100 itself has a certain thermal insulation ability, so that the thickness of the third insulating layer 50 can be reduced to a certain extent (for example, the thickness is reduced to less than or equal to 3500μm). The thinner third insulating layer 50 is superimposed on the second insulating layer 40. On the one hand, it can jointly isolate the heat conduction between adjacent battery cells 100 and solve the problem of comprehensive thermal runaway. On the other hand, it is easy to realize the miniaturized design of the battery module 2000 and improve the energy density of the battery cell 100.

[0127] In some embodiments, the material of the second insulating layer 40 may include aerogel or ceramic material.

[0128] Exemplarily, the thickness of the second insulating layer 40 may be less than or equal to 300 μm.

[0129] For example, when the material of the second insulating layer 40 is aerogel, the thickness of the second insulating layer 40 may be less than or equal to 300 μm, for example, 30 μm to 300 μm, for example, 30 μm, 110.5 μm, 253.75 μm or 300 μm.

[0130] For example, when the material of the second insulating layer 40 is a ceramic material, the thickness of the second insulating layer 40 may be less than or equal to 200 μm, for example, 10 μm to 200 μm, for example, 10 μm, 83.6 μm, 105.75 μm or 200 μm.

[0131] By configuring the material of the second insulating layer 40 to include aerogel, it is possible to ensure that the battery cell 100 has a lighter weight while achieving high-temperature electrical insulation properties.

[0132] By setting the material of the second insulating layer 40 to include a ceramic material, the second insulating layer 40 can be ensured to have a relatively thin thickness while achieving high-temperature electrical insulation characteristics, thereby ensuring a miniaturized design of the battery cell 100 .

[0133] Figure 7 , Figure 8 and Fig. 9 They are respectively another structural schematic diagram of the battery cell 100 provided in an embodiment of the present application.

[0134] In some embodiments, Figure 7 As shown, the second insulating layer 40 can be attached to the inner wall of the housing 10 and disposed between the inner wall of the housing 10 and the first insulating layer 30 .

[0135] Exemplarily, the second insulating layer 40 may be fixed by bonding. For example, the second insulating layer 40 may be fixed after adhesive is coated on its surface, or the material of the second insulating layer 40 may be mixed with adhesive before fixing.

[0136] By attaching the second insulating layer 40 to the inner wall of the shell 10, the process of preparing the second insulating layer 40 can avoid damage to the structure of the pole core 20, thereby improving the product yield of the battery cell 100. In addition, the second insulating layer 40 is arranged between the first insulating layer 30 and the shell 10, which can effectively isolate the heat from the shell 10 to the first insulating layer 30, thereby improving the electrical insulation ability of the first insulating layer 30 in a high temperature environment, and further improving the stability of the battery cell 100.

[0137] In some embodiments, Figure 3 and Figure 8 As shown, the second insulating layer 40 can be attached to the surface of the pole core 20. For example, when the outermost circle of the pole core 20 is the negative electrode sheet 22, the second insulating layer 40 is attached to the outermost circle of the negative electrode sheet 22 of the pole core 20.

[0138] By attaching the second insulating layer 40 to the outer surface of the pole core 20 , the difficulty of preparing the second insulating layer 40 can be reduced, and the bonding strength of the second insulating layer 40 can be ensured, thereby improving the stability of the battery cell 100 .

[0139] For example, in other embodiments, the second insulating layer 40 may also be attached to a side surface of the first insulating layer 30 close to the inner wall of the outer shell 10, or attached to a side surface of the first insulating layer 30 away from the inner wall of the outer shell 10, and the present application does not limit this.

[0140] In some embodiments, Figure 3 and Figure 7 As shown, the shell 10 is substantially strip-shaped, and the second insulating layer 40 is located between the edge of the shell 10 in the length extension direction and the pole core 20 .

[0141] The side of the battery cell 100 is subjected to greater force in the length extension direction. When the external environment temperature of the battery cell 100 is too high, the first insulating layer 30 gradually melts. The first insulating layer 30 located at the longer side of the battery cell 100 will move under force (such as squeezing), resulting in the loss of the first insulating layer 30 material at this position, which can easily cause a short circuit between the outer shell 10 and the pole core 20 at this position.

[0142] By providing a second insulating layer 40 between the edge of the outer shell 10 in the length extension direction and the pole core 20 (i.e., in the length direction of the battery cell 100), the position where the first insulating layer 30 may melt or deform (i.e., the portion of the first insulating layer 30 located on the longer side of the battery cell 100) can be covered by the second insulating layer 40. When the operating temperature of the battery cell 100 is too high, causing the first insulating layer 30 in the length direction of the battery cell 100 to melt or deform, the second insulating layer 40 can still continue to maintain electrical insulation, thereby avoiding a short circuit between the outer shell 10 and the pole core 20, thereby improving the safety performance of the battery cell 100.

[0143] In some embodiments, Figure 2 As shown, the second insulating layer 40 is adjacent to and faces the first side surface 10A of the housing 10 .

[0144] Among them, see Figure 2 The first side surface 10A of the housing 10 is the housing 10 and other housings (eg Figure 2 The surface adjacent to the shell where the battery cell 101 is located.

[0145] Exemplarily, the battery module 2000 includes at least two adjacent battery cells 100, and usually the longer sides of the two battery cells 100 are arranged close to each other, and the second insulating layer 40 is located on the sides of the two adjacent battery cells 100 that are close to each other (i.e., the longer sides).

[0146] The side of the battery cell 100 is subjected to greater force in the length extension direction, and when one of the battery cells 100 fails (for example, burns) and generates heat, the heat is mostly spread from the longer side of the battery cell 100, causing the first insulating layer 30 on the longer side of the battery cell 100 to melt and deform easily, resulting in a short circuit and arcing between the outer shell 10 and the pole core 20.

[0147] By arranging the second insulating layer 40 adjacent to and facing the first side surface 10A (for example, on the surface of the battery cell 101 adjacent to the first side surface 10A or on the inner wall of the housing 10 adjacent to the first side surface 10A), the second insulating layer 40 can be placed adjacent to the first side surface 10A in other battery cells 100 (for example Figure 2 In the event of thermal runaway of the battery cell 101 in the embodiment, heat can be effectively prevented from being transferred from the first side surface 10A to the normal battery cell 100 (e.g. Figure 2 In the battery cell 102), thereby avoiding a chain reaction of large-scale thermal runaway.

[0148] In some embodiments, Figure 8 and Fig. 9As shown, the second insulating layer 40 is arranged around the pole core 20. That is, the second insulating layer 40 is arranged in a full circle, and the second insulating layer 40 is arranged at all sides of the battery cell 100 (including the sides with longer lengths of the battery cell 100), thereby further improving the electrical insulation ability of the second insulating layer 40 to the pole core 20. For example, when the operating temperature of the battery cell 100 is very high, resulting in a high degree of melting of the first insulating layer 30, the electrical insulation ability between the shell 10 and the pole core 20 can still be guaranteed.

[0149] In some embodiments, Figure 3 , Figure 7 , Figure 8 and Fig. 9 As shown, the aforementioned negative electrode sheet 22 includes a first sub-section 2A and a second sub-section 2B, and the first sub-section 2A, the separator 23 and the positive electrode sheet 21 are arranged alternately in sequence, and the second sub-section 2B is the portion of the negative electrode sheet 22 that exceeds the end of the positive electrode sheet 21, and the second sub-section 2B is arranged around the outermost layer of the electrode core 20.

[0150] That is, the first sub-portion 2A is the portion of the negative electrode sheet 22 that is directly opposite to the positive electrode sheet 21 and can carry out ion migration with the positive electrode sheet 21, and the second sub-portion 2B surrounds the outermost circle of the pole core 20, thereby protecting the positive electrode sheet 21 and preventing the positive electrode sheet 21, which is made of a relatively precious material and has a higher cost, from being damaged when it is in the outermost layer.

[0151] See also Figure 7 and Figure 8 , the aforementioned second insulating layer 40 can be disposed on the second sub-portion.

[0152] For example, see Figure 7 and Figure 8 , the negative electrode active layer 222 in the second sub-portion 2B covers the surface of the negative electrode current collector 221 on one side close to the positive electrode sheet 21 and the surface of the side away from the positive electrode sheet 21. That is, the part of the negative electrode sheet 22 disposed on the outermost layer of the electrode core 20 (i.e., the second sub-portion 2B) has a complete negative electrode current collector 221 and a negative electrode active layer 222, so that the preparation process of the electrode core 20 can be simplified. For example, the preparation of the negative electrode sheet 22 can be realized by a continuous coating process.

[0153] Specifically, the second insulating layer 40 is arranged on the second sub-section, and the second insulating layer 40 can be arranged on the negative electrode active layer 222 on the side surface of the second sub-section 2B away from the positive electrode sheet 21, that is, the outermost layer of the pole core 20 is the negative electrode active layer 222 of the second sub-section 2B, and the second insulating layer 40 is arranged on the negative electrode active layer 222.

[0154] Exemplarily, in this embodiment, the second insulating layer 40 is disposed around the pole core 20 , or is disposed only on a side of the pole core 20 with a longer length.

[0155] For example, see Fig. 9 The negative electrode active layer 222 in the second sub-section 2B covers the surface of the negative electrode collector 221 on one side close to the positive electrode sheet 21 , and the negative electrode collector 221 in the second sub-section 2B serves as the outermost layer of the electrode core 20 .

[0156] Specifically, the second insulating layer 40 is disposed on the second sub-section, and the second insulating layer 40 replaces the negative electrode active layer 222 on the side surface of the second sub-section 2B away from the positive electrode sheet 21 and is disposed on the negative electrode collector 221 of the second sub-section 2B.

[0157] That is, the negative electrode active layer 222 located on the outermost layer of the electrode core 20 (i.e., the second sub-section 2B) is removed, and the negative electrode active layer 222 close to the inner side of the accommodating cavity Q is removed, so that the outermost layer of the electrode core 20 is the negative electrode collector 221 of the second sub-section 2B, and the second insulating layer 40 is arranged on the negative electrode collector 221 of the second sub-section 2B, which is equivalent to replacing the negative electrode active layer 222 of the outer layer of the second sub-section 2B with the second insulating layer 40. In this way, while ensuring the function of the electrode core 20, the size of the electrode core 20 can be avoided from being increased after the second insulating layer 40 is arranged, thereby facilitating the miniaturization design of the battery cell 100 and avoiding affecting the energy density of the battery cell 100.

[0158] For example, the negative electrode sheet 22 can be prepared by a continuous coating process, and the negative active layer 222 on one side of the negative electrode collector 221 is scraped off from the portion of the negative electrode sheet 22 belonging to the second sub-portion 2B, and then rolled or stacked to form the electrode core 20 .

[0159] Exemplarily, in this embodiment, the second insulating layer 40 is disposed around the pole core 20 , or is disposed only on a side of the pole core 20 with a longer length.

[0160] For example, see Figure 3 The negative electrode active layer 222 in the second sub-section 2B covers the side surface of the negative electrode collector 221 close to the positive electrode sheet 21 and the side surface away from the positive electrode sheet 21, and the negative electrode active layer 222 on the side surface of the second sub-section 2B away from the positive electrode sheet 21 is provided with a receiving groove U.

[0161] Specifically, the second insulating layer 40 is disposed on the second sub-portion, and the second insulating layer 40 is disposed in the receiving groove U.

[0162] That is, the negative electrode active layer 222 is removed only at the position where the second insulating layer 40 is set. This can also ensure the function of the pole core 20 while avoiding increasing the size of the pole core 20 after setting the second insulating layer 40, thereby facilitating the miniaturization design of the battery cell 100 and avoiding affecting the energy density of the battery cell 100.

[0163] Exemplarily, the negative electrode sheet 22 can be prepared by a continuous coating process, and a portion of the negative electrode active layer 222 is dug out at a preset position to form the receiving groove U. Alternatively, the negative electrode sheet 22 can be prepared by a gap coating process, and the position of the receiving groove U is reserved during the gap coating process.

[0164] For example, see Figure 3 In this embodiment, the second insulating layer 40 is disposed on the longer side of the pole core 20 .

[0165] Fig.10 Another structural schematic diagram of the battery cell 100 provided in an embodiment of the present application. Fig.11 For along Fig.10 Side view in the C direction.

[0166] The application embodiment also provides a battery cell 100. In some embodiments, as Fig.10 and Fig.11 As shown, the battery cell 100 may include a housing 10 , a pole core 20 and a second insulating layer 40 .

[0167] Among them, see Fig.10 and Fig.11 , the second insulating layer 40 is arranged around the pole core 20 and is located between the inner wall of the shell 10 and the pole core 20. That is, the second insulating layer 40 is arranged in a full circle, so as to achieve electrical insulation between the shell 10 and the pole core 20 at any position.

[0168] The maximum tolerable temperature of the second insulating layer 40 is greater than or equal to 300° C.

[0169] It can be understood that the features of the structures such as the shell 10, the pole core 20 and the second insulating layer 40 in this embodiment can all refer to the corresponding descriptions in the aforementioned embodiments and will not be repeated here.

[0170] By providing a second insulating layer 40 around the pole core 20, it can be ensured that the battery cell 100 can still maintain electrical insulation in a high temperature environment, avoid short circuit between the outer shell 10 and the pole core 20, and improve the safety performance of the battery cell 100. In addition, there is no need to provide a first insulating layer 30 in the battery cell 100 with a second insulating layer 40 arranged in a whole circle. On the one hand, it can simplify the preparation process of the battery cell 100, and on the other hand, it is easy to reduce the size of the battery cell 100, realize the miniaturized design of the battery cell 100, and avoid affecting the energy density of the battery cell 100.

[0171] In some embodiments, see Fig.10 The second insulating layer 40 can be attached to the inner wall of the shell 10, which can reduce the requirements for the flexibility of the second insulating layer 40, thereby reducing the difficulty of preparing the battery cell 100 while achieving high-temperature insulation.

[0172] In some embodiments, Fig.12 As shown, the battery cell 100 includes a plurality of pole cores 20 , and the plurality of pole cores 20 are arranged in an array. Fig.12 The two pole cores 20 are merely taken as an example for schematic illustration, and are not intended to be limiting.

[0173] For example, see Fig.12 The second insulating layer 40 can be arranged on the longer side of the pole core 20, or illustratively, a circle of the second insulating layer 40 (not shown in the figure) is correspondingly arranged on the outer circle of each pole core 20 to further enhance the heat insulation effect.

[0174] Fig.13 A temperature change diagram of a battery cell during a thermal runaway experiment provided in an embodiment of the present application; Fig.14 Graph showing the temperature variation of a comparative sample (a battery cell without the second insulating layer 40) during a thermal runaway experiment.

[0175] Among them, Fig.13 and Fig.14 As shown, the horizontal axis in the temperature change diagram is time, and the vertical axis is the temperature of the battery cell to be tested. Fig.13 and Fig.14 The curve in can represent the temperature of the battery cell under test at different time nodes.

[0176] It should be noted that, during the experiment, a battery cell for forced thermal runaway and a battery cell to be tested adjacent to the battery cell for forced thermal runaway may be included. Fig.13 In the embodiment, the battery cell to be tested is a battery cell 100 provided with the second insulating layer 40 described in the embodiment of the present application. Fig.14 The battery cell to be tested is a battery cell without the second insulating layer 40.

[0177] like Fig.14 It can be seen that in the comparison samples, when adjacent battery cells are forced into thermal runaway, the temperature of the battery cell to be tested will gradually increase, and after exceeding 100°C, the temperature will rise rapidly in a short period of time, and eventually rise to nearly 1000°C, triggering large-scale thermal runaway, which is extremely dangerous.

[0178] And as Fig.13 It can be seen that in the battery cell 100 provided in the embodiment of the present application, the second insulating layer 40 is provided to effectively suppress the occurrence of thermal runaway in a large area. Fig.13 After the thermal runaway experiment occurs, the temperature of the adjacent battery cells (i.e., the battery cells to be tested) can be heated to above 150°C, or even close to 200°C, for more than 10 minutes by forcing the battery cells that fail due to thermal runaway to fail. Then, the temperature of the battery cells to be tested gradually decreases to below 100°C, effectively avoiding the chain reaction of thermal runaway.

[0179] In addition, the application also tested and analyzed the voltage of the two groups of cells to be tested during the experiment, and the results are as follows:

[0180] During the experiment of the comparison samples, after the adjacent battery cells were forced to thermally runaway, the voltage of the battery cells to be tested began to fluctuate, and after the temperature exceeded 100°C, the voltage of the battery cells to be tested dropped rapidly and finally dropped to 0V, indicating that serious arc discharge occurred in the battery cells to be tested and serious functional failure occurred in the battery module where the battery cells to be tested were located.

[0181] During the experiment on the battery cells to be tested provided in the present application, the voltage of the battery cells to be tested provided in the embodiments of the present application was relatively stable, that is, there was no problem of battery module function failure.

[0182] To sum up, the battery cell 100 provided in the embodiment of the present application effectively solves the problem of large-area thermal runaway, thereby improving the reliability and safety factor of the battery cell 100. In addition, it can also avoid functional failure of the battery cell 100 (such as arcing and other problems), thereby also improving the reliability of the battery cell 100.

[0183] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A battery cell, characterized in that: include: A housing, wherein the housing is arranged to form a receiving cavity; A pole core is arranged in the accommodating cavity; the pole core comprises a positive pole sheet, a negative pole sheet and a separator, and the positive pole sheet, the separator and the negative pole sheet are arranged alternately in sequence; A first insulating layer is arranged around the pole core and is located between the inner wall of the shell and the pole core; The second insulating layer is located between the inner wall of the shell and the pole core; the maximum tolerable temperature of the second insulating layer is greater than or equal to 300°C.

2. The battery cell according to claim 1, characterized in that: The second insulating layer is attached to the inner wall of the shell and is arranged between the inner wall of the shell and the first insulating layer.

3. The battery cell according to claim 1, characterized in that: The second insulating layer is attached to the surface of the pole core.

4. The battery cell according to claim 3, characterized in that: The negative electrode sheet includes a first sub-section and a second sub-section, wherein the first sub-section, the separator and the positive electrode sheet are arranged alternately in sequence, the second sub-section is a portion of the negative electrode sheet that exceeds the end of the positive electrode sheet, and the second sub-section is arranged around the outermost layer of the electrode core, and the second insulating layer is arranged on the second sub-section.

5. The battery cell according to claim 4, characterized in that: The second insulating layer is disposed on the second sub-section specifically: The second insulating layer is disposed on the negative electrode active layer on a surface of the second sub-section that is away from the positive electrode sheet.

6. The battery cell according to claim 4, characterized in that: The second insulating layer is disposed on the second sub-section specifically in that the second insulating layer replaces the negative electrode active layer on the surface of the second sub-section on one side away from the positive electrode sheet and is disposed on the negative electrode collector of the second sub-section.

7. The battery cell according to claim 4, characterized in that: The second insulating layer is disposed on the second sub-section specifically: A receiving groove is provided in the negative electrode active layer on the surface of one side of the second sub-part away from the positive electrode sheet; and the second insulating layer is arranged in the receiving groove.

8. The battery cell according to any one of claims 1 to 6, characterized in that: The second insulating layer is disposed around the pole core.

9. The battery cell according to any one of claims 1 to 7, characterized in that: The second insulating layer is adjacent to and facing the first side surface of the shell; the first side surface of the shell is a surface of the shell used to be arranged adjacent to other battery cells.

10. The battery cell according to any one of claims 1 to 9, characterized in that: The positive electrode sheet, the separator and the negative electrode sheet are stacked; or, The positive electrode sheet, the separator and the negative electrode sheet are wound together.

11. The battery cell according to any one of claims 1 to 10, characterized in that: The material of the second insulating layer includes aerogel; and / or the thickness of the second insulating layer is less than or equal to 300 μm.

12. The battery cell according to any one of claims 1 to 10, characterized in that: The material of the second insulating layer includes a ceramic material; and / or the thickness of the second insulating layer is less than or equal to 200 μm.

13. A battery cell, characterized in that: include: A housing, wherein the housing is arranged to form a receiving cavity; A pole core is arranged in the accommodating cavity; the pole core comprises a positive pole sheet, a negative pole sheet and a separator, and the positive pole sheet, the separator and the negative pole sheet are arranged alternately in sequence; The second insulating layer is arranged around the pole core and is located between the inner wall of the shell and the pole core; the maximum tolerable temperature of the second insulating layer is greater than or equal to 300°C.

14. The battery cell according to claim 13, characterized in that: The second insulating layer is attached to the inner wall of the shell.

15. A battery module, characterized in that: include: One or more battery cells as claimed in any one of claims 1 to 14; A battery management system, the one or more battery cells are electrically connected to the battery management system.

16. The battery module according to claim 15, characterized in that: The plurality of battery cells include at least one pair of two battery cells arranged adjacent to each other; The battery module also includes: A third insulating layer, the third insulating layer being sandwiched at least between the two adjacent battery cells; The thickness of the third insulating layer is less than or equal to 3500 μm.

17. An electronic device, characterized in that: include: The battery cell according to any one of claims 1 to 14; A controller is electrically connected to the battery cell.

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