Battery monomer, battery and electric device

Abstract

The embodiment of the invention provides a battery monomer, a battery and a power utilization device. The battery monomer comprises a first wall, a pressure relief mechanism and an insulating part, the pressure relief mechanism is arranged on the first wall, and the pressure relief mechanism is provided with a first weak area; the insulating part is arranged on one side, facing the electrode assembly of the battery monomer, of the first wall, and the orthographic projection of the insulating part on the first wall covers the first weak area. The first weak area is covered by the insulating part, so that the impact of a medium, such as an electrolyte, in the battery monomer on the first weak area can be reduced, the protection effect of the insulating part on the first weak area is enhanced, the risk that the first weak area is opened by impact under a non-emergency condition is reduced, and the safety of the battery is improved.

Description

Battery cells, batteries and electrical devices Technical Field

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

[0002] As the depletion of natural resources and environmental damage worsen, interest in devices that can store and effectively utilize energy is growing in various fields. Battery cells are systems that can be combined to utilize new renewable energy.

[0003] In the field of battery equipment technology, a pressure relief mechanism is typically provided on the battery cell housing, which can connect the inside and outside of the battery in the event of thermal runaway. However, if it is opened in non-emergency situations, it will seriously affect the safety of the battery cell.

[0004] Application Contents

[0005] The embodiments of the present application provide a battery cell, a battery, and an electrical device, which can reduce the possibility of a pressure relief mechanism being activated during normal use of the battery cell, thereby improving the safety of the battery.

[0006] In a first aspect of an embodiment of the present application, a battery cell is provided, comprising a first wall, a pressure relief mechanism, and an insulating member. The pressure relief mechanism is disposed on the first wall and has a first weakened area. The insulating member is disposed on a side of the first wall facing the electrode assembly of the battery cell, with the insulating member's orthographic projection on the first wall covering the first weakened area.

[0007] By adopting the above structure, by covering the first weak area with an insulating part, the impact of the medium in the battery cell, such as electrolyte, on the first weak area can be reduced, the protective effect of the insulating part on the first weak area can be strengthened, the risk of the first weak area being opened by impact in non-emergency situations is reduced, and the battery safety is improved. For example, when the battery cell is inverted, the medium in the battery cell compresses the first weak area under the action of gravity, causing the first weak area to rupture and the pressure relief mechanism to open. After the insulating part is set to cover the first weak area, the insulating part can effectively share the force pressing on the first weak area, that is, the compressive force on the first weak area is reduced, thereby preventing the first weak area from being pressed and ruptured, causing the pressure relief mechanism to open by mistake.

[0008] In some optional embodiments of the present application, the first wall includes a pressure relief hole, the pressure relief mechanism is an explosion-proof plate, the explosion-proof plate closes the pressure relief hole, the explosion-proof plate is provided with a main body and a second weak area, the main body is connected to the first wall, the first weak area is arranged in the second weak area, the thickness of the first weak area is less than the thickness of the second weak area, the thickness of the second weak area is less than the thickness of the main body, and the positive projection of the insulating member on the first wall covers the second weak area.

[0009] By adopting the above structure, by setting the pressure relief mechanism as an explosion-proof plate, the structure on the first wall can be simplified and the overall strength of the first wall can be improved; secondly, by setting a second weak area with a thickness greater than the first weak area and smaller than the main body, the strength at the first weak area can be reduced, which makes it easier for the first weak area to be ruptured by impact, and also makes it easier for the second weak area to follow the rupture when the first weak area ruptures, thereby expanding the rupture range and improving the pressure relief capacity. Thirdly, by covering the second weak area with an insulating part, the impact of the medium in the battery cell, such as the electrolyte, on the second weak area can be reduced, thereby strengthening the protective effect of the insulating part on the second weak area.

[0010] In some optional embodiments of the present application, a through hole is provided on the insulating member and passes through the first wall in a thickness direction thereof, and an orthographic projection of the through hole on the first wall does not overlap with the first weak area.

[0011] By adopting the above structure, by providing a through hole that does not overlap with the first weak area, the insulating part can be guaranteed to protect the first weak area. At the same time, it is convenient for the battery cell to be in an emergency situation, such as when the battery cell thermal runaway produces a large amount of gas. The gas in the battery cell can quickly pass through the insulating part, and then impact the first weak area to open the pressure relief mechanism, thereby improving the pressure relief response speed and enhancing the safety of the battery cell.

[0012] In some optional embodiments of the present application, the first wall includes a pressure relief hole, the pressure relief mechanism is a bursting disc, the bursting disc closes the pressure relief hole, and the orthographic projection of the through hole on the first wall does not overlap with the bursting disc.

[0013] By adopting the above structure, by providing a through hole that does not overlap with the explosion-proof plate, the protective effect of the insulating member on the first weak area can be improved, and the through hole is arranged away from the area where the pressure relief mechanism is located, thereby reducing the risk of the medium in the battery cell passing through the insulating member and impacting the first weak area in non-emergency situations.

[0014] In some optional embodiments of the present application, the insulating member includes a first area, the first area is arranged corresponding to the area surrounded by the first weak area, and the through hole is arranged around the first area.

[0015] With the above structure, by arranging the through holes around the first area, the high-temperature gas in the battery cell can pass through the insulating member and be close to the first weak area, which is convenient for impacting the first weak area to open the pressure relief mechanism in an emergency.

[0016] In some optional embodiments of the present application, a plurality of through holes may be provided, and the plurality of through holes are arranged at intervals around the first region.

[0017] With the above structure, by arranging the through holes at intervals around the first area, a structure without through holes exists around the first area, which can improve the strength of the first area and also enhance the protection of the first weak area by the insulating member.

[0018] In some optional embodiments of the present application, the positive projection of the first weak zone on the insulating member includes an arc-shaped boundary. In the radial direction of the arc-shaped boundary, the minimum distance between the through hole and the arc-shaped boundary is D1, and the radius of the arc-shaped boundary is D2, satisfying 0≤D1 / D2≤1.

[0019] By adopting the above structure, the range of the through hole around the first weak area can be constrained by constraining the D1 / D2 range. On the one hand, it ensures that the high-temperature gas in the battery cell is close to the first weak area after passing through the insulating part, thereby improving the response speed. On the other hand, it also prevents the high-temperature gas in the battery cell from passing through the insulating part and being far away from the first weak area, resulting in the inability to quickly impact the first weak area and cause the pressure relief mechanism to open quickly.

[0020] In some optional embodiments of the present application, the insulating member is provided with a third weak area, and the third weak area is configured to be destroyed when the battery cell thermally runs away, so that gas passes through the third weak area and acts on the first weak area.

[0021] By adopting the above structure and setting the third weak zone, on the one hand, the penetrating structure on the insulating part can be reduced, further reducing the impact of the medium (such as electrolyte) in the battery cell on the first weak zone, and strengthening the protective effect of the insulating part on the first weak zone. On the other hand, the third weak zone can also be broken by the impact of the high-temperature gas in the battery cell in an emergency, thereby allowing the high-temperature gas in the battery cell to pass through and trigger the pressure relief process.

[0022] In some optional embodiments of the present application, the third weak area includes a reduced thickness area, and the thickness of the reduced thickness area is smaller than the thickness of other areas on the insulating member.

[0023] With the above structure, by providing the thickness-reduced area, the third weak area can be easily crushed by the impact of the high-temperature gas in the battery cell.

[0024] In some optional embodiments of the present application, the orthographic projection of the reduced thickness area on the first wall at least partially overlaps with the first weak area.

[0025] By adopting the above structure, by providing a thickness reduction area that at least partially overlaps with the first weak area, the high-temperature gas in the battery cell can impact and crush the thickness reduction area and directly correspond to the first weak area, thereby improving the pressure relief response speed and enhancing the safety of the battery cell.

[0026] In some optional embodiments of the present application, a through hole is provided on the insulating member and passes through the first wall in a thickness direction thereof, and an orthographic projection of the through hole on the first wall does not overlap with the first weak area.

[0027] With the above structure, by providing the through hole, it is possible to facilitate the high-temperature gas in the battery cell to pass through the insulating member and impact the first weak area, thereby increasing the pressure relief response speed and improving the safety of the battery cell.

[0028] In some optional embodiments of the present application, the thickness of the reduced thickness area is D3, the insulating member includes a second area connected to the reduced thickness area, the thickness of the second area is D4, and 0<D3 / D4≤0.8 is satisfied.

[0029] By adopting the above structure, by constraining the ratio of D3 / D4 to be in the range of 0 to 0.8, the requirement that the thickness reduction area is easily broken to form a channel in an emergency situation can be met.

[0030] According to a second aspect of the embodiments of the present application, a battery is provided, comprising the above-mentioned battery cell.

[0031] According to a third aspect of the embodiments of the present application, there is provided an electrical device comprising the above-mentioned battery cell, wherein the battery cell is used to provide electrical energy.

[0032] Compared with the related art, in the battery cell, battery and electrical device of the embodiment of the present application, by covering the first weak area with an insulating part, the impact of the medium in the battery cell, such as electrolyte, on the first weak area can be reduced, the protective effect of the insulating part on the first weak area is strengthened, the risk of the first weak area being opened by impact in non-emergency situations is reduced, and the battery safety is improved. For example, when the battery cell is inverted, the medium in the battery cell compresses the first weak area under the action of gravity, causing the first weak area to rupture and the pressure relief mechanism to open. After the insulating part is set to cover the first weak area, the insulating part can effectively share the force pressing on the first weak area, that is, the compressive force on the first weak area is reduced, thereby preventing the first weak area from being pressed and ruptured, causing the pressure relief mechanism to open by mistake. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0034] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0035] FIG2 is a schematic diagram of the structure of a battery provided in some embodiments of the present application.

[0036] FIG3 is a schematic structural diagram of a battery cell provided in some embodiments of the present application.

[0037] FIG4 is a schematic structural diagram of the first wall provided in some embodiments of the present application.

[0038] FIG5 is a schematic diagram of the structure of the explosion-proof disk provided in some embodiments of the present application.

[0039] FIG6 is a schematic diagram of a long-axis cross-sectional structure of a first wall provided in some embodiments of the present application.

[0040] FIG7 is a schematic diagram of the local structure of point B in FIG6 .

[0041] FIG8 is a schematic structural diagram of an insulating member provided in some other embodiments of the present application.

[0042] FIG9 is a bottom view of the structure of the embodiment shown in FIG8 .

[0043] FIG10 is a schematic diagram of a short-axis cross-sectional structure of the first wall provided in some other embodiments of the present application.

[0044] FIG11 is a schematic diagram of an orthographic projection of a first weak area on an insulating member provided in some other embodiments of the present application.

[0045] FIG12 is a schematic diagram of the short-axis cross-sectional structure of the first wall provided in some further embodiments of the present application.

[0046] FIG13 is a schematic structural diagram of an insulating member provided in some further embodiments of the present application.

[0047] FIG14 is a bottom view of the structure of the embodiment shown in FIG13 .

[0048] FIG15 is a bottom view schematic diagram of the insulating member provided in some further embodiments of the present application.

[0049] FIG16 is a schematic diagram of the short-axis cross-sectional structure of the first wall provided in some other embodiments of the present application.

[0050] In the accompanying drawings: 1000, vehicle; 100, battery; 200, controller; 300, motor; 110, box; 111, first box part; 112, second box part; 1, outer shell; 101, first wall; 102, shell; 103, electrode assembly; 104, pressure relief hole; 105, electrode terminal; 2, pressure relief mechanism; 21, explosion-proof plate; 211, first weak area; 212, reinforcing rib; 213, main body; 214, second weak area; 3, insulating part; 31, first area; 311, arc-shaped boundary; 312, straight line boundary; 32, through hole; 33, third weak area; 331, thickness reduction area; 34, second area. DETAILED DESCRIPTION

[0051] The following embodiments of the technical solution of the present application are described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0053] In the description of the implementation methods of this application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0054] Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it refer to independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0055] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the related objects are in an "or" relationship.

[0056] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0057] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of 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. Therefore, they should not be understood as limiting the embodiments of the present application.

[0058] In the description of the embodiments of this application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of this application based on specific circumstances.

[0059] In this application, battery cells may include lithium-ion battery cells, lithium-sulfur battery cells, sodium-lithium-ion battery cells, sodium-ion battery cells, or magnesium-ion battery cells, and the embodiments of this application are not limited to this. Battery cells may be cylindrical, flat, rectangular, or other shapes, and the embodiments of this application are not limited to this. Battery cells may be hard-shell battery cells, soft-pack battery cells, or other types of battery cells.

[0060] A battery cell includes an electrode assembly and an electrolyte. Exemplarily, the electrode assembly includes a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell primarily operates by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer, which is coated on the surface of the positive current collector. The positive current collector includes a positive current collector portion and a positive tab, which is coated with the positive active material layer, while the positive tab is uncoated. For example, in a lithium-ion battery cell, the positive current collector can be made of aluminum, and the positive active material layer includes a positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer, which is coated on the surface of the negative current collector. The negative current collector includes a negative current collector portion and a negative tab, which is coated with the negative active material layer, while the negative tab is uncoated. The negative electrode current collector may be made of copper, and the negative electrode active material layer includes a negative electrode active material, which may be carbon or silicon, etc. The separator may be made of PP (polypropylene) or PE (polyethylene), etc.

[0061] The battery referred to in the embodiments of this application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. A battery generally includes a housing that encloses one or more battery cells. The housing prevents liquids or other foreign matter from affecting the charging or discharging of the battery cells.

[0062] The development of battery technology must take into account multiple design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery safety must also be considered.

[0063] The pressure relief mechanism on a battery cell has a significant impact on its safety. For example, short circuits, overcharging, and other events can cause thermal runaway within the cell, leading to a sudden increase in pressure. In these situations, the pressure relief mechanism activates to release the internal pressure, preventing explosion or fire.

[0064] A pressure relief mechanism can be an element or component that activates when a battery cell reaches certain conditions. For example, it can be activated to release internal pressure and / or internal materials when the internal pressure or temperature of the battery cell reaches a predetermined threshold. This threshold design varies depending on design requirements. This threshold may depend on the materials of one or more of the positive electrode plate, negative electrode plate, electrolyte, and separator in the battery cell.

[0065] The pressure relief mechanism can take the form of an explosion-proof valve, an air valve, a pressure relief valve, or a safety valve, and can specifically employ a pressure-sensitive element or structure. Specifically, when the internal pressure of the battery cell reaches a predetermined threshold, the pressure relief mechanism activates or a weak area within the pressure relief mechanism ruptures, thereby forming a pressure relief channel for internal pressure relief. Alternatively, the pressure relief mechanism can employ a temperature-sensitive element or structure. Specifically, when the internal temperature of the battery cell reaches a predetermined threshold, the pressure relief mechanism activates, thereby forming a pressure relief channel for internal pressure relief. Alternatively, the pressure relief mechanism can be an actively actuated component. For example, the pressure relief mechanism can be actuated upon receiving a control signal from the battery.

[0066] The pressure relief mechanism can also take other forms. For example, the pressure relief mechanism can be a relatively low-strength structure on the battery cell's outer shell. When the battery cell experiences thermal runaway, the relatively low-strength structure cracks or deforms, forming a pressure relief channel for internal pressure relief. For example, the pressure relief mechanism can be a weld mark on the battery cell's outer shell.

[0067] The "activation" mentioned in this application refers to the action of the pressure relief mechanism or its activation to a certain state, so that the internal pressure and / or internal substances of the battery cell can be released. The action produced by the pressure relief mechanism may include but is not limited to: at least a part of the pressure relief mechanism is broken, shattered, torn or opened, etc. When the pressure relief mechanism is actuated, the high-temperature and high-speed substances inside the battery cell will be discharged outward from the actuated part as emissions. In this way, the battery cell can be depressurized under controllable pressure, thereby avoiding potential more serious accidents.

[0068] The inventors noted that the triggering condition for the pressure relief mechanism is actually that the pressure acting on the pressure relief mechanism exceeds a threshold value, and the medium in the internal environment of the battery has fluid properties, so that the pressure in different places in the internal environment of the battery may be different. This leads to the situation that even under normal use of the battery (such as when the battery is inverted or placed on its side, so that the pressure relief mechanism is located at the bottom end of the battery in the direction of gravity), the local pressure at the pressure relief mechanism is relatively high, causing the pressure relief mechanism to open, causing an accident, and in turn reducing the safety of the battery.

[0069] In order to alleviate the problem of low battery safety, the inventors have found that by adjusting the structure of the pressure relief mechanism and appropriately shielding the pressure relief mechanism, the force on the pressure relief mechanism can be reduced under normal use, reducing the risk of accidental opening of the pressure relief mechanism and effectively improving the safety of the battery.

[0070] Based on the above considerations, the inventors of the present application have conducted in-depth research and designed a battery cell, a battery and an electrical device.

[0071] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0072] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device according to an embodiment of the present application.

[0073] FIG1 is a schematic structural diagram of a vehicle 1000 provided in some embodiments of the present application. As shown in FIG1 , the vehicle 1000 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A battery 100 is provided inside the vehicle 1000, and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000. The battery 100 may be used to power the vehicle 1000, for example, the battery 100 may serve as an operating power source for the vehicle 1000. The vehicle 1000 may further include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to power the motor 300, for example, for starting, navigating and operating power requirements of the vehicle 1000 during driving.

[0074] In some embodiments of the present application, the battery 100 can serve not only as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0075] In the embodiments of the present application, the battery mentioned herein refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned herein may include a battery module or a battery pack.

[0076] Figure 2 is a schematic diagram of the structure of the battery 100 provided in some embodiments of the present application. As shown in Figure 2, in some embodiments of the present application, the battery 100 includes a housing 110, and the housing 110 may include a first housing portion 111 and a second housing portion 112 connected to each other. A plurality of battery cells are connected in parallel, in series, or in a mixed combination and placed in a space formed by the connection of the first housing portion 111 and the second housing portion 112. The shape of the first housing portion 111 and the second housing portion 112 can be determined according to the shape of the combination of the plurality of battery cells. The battery cell may be cylindrical, flat, rectangular, or in other shapes, and the embodiments of the present application are not limited thereto. The packaging methods of the battery cell include, but are not limited to, cylindrical battery cells, square battery cells, and soft-pack battery cells, and the embodiments of the present application are not specifically limited thereto. In addition, the battery 100 may also include other structures, such as a busbar component, for realizing electrical connection between a plurality of battery cells, which will not be described one by one here.

[0077] Figure 3 is a schematic diagram of the structure of a battery cell provided in some embodiments of the present application, Figure 4 is a schematic diagram of the structure of the first wall 101 provided in some embodiments of the present application, and Figure 5 is a schematic diagram of the structure of the explosion-proof disk 21 provided in some embodiments of the present application. As shown in Figures 3 to 5, in some embodiments of the present application, a battery cell 10 is provided, comprising a first wall 101, a pressure relief mechanism 2, and an insulating member 3. The pressure relief mechanism 2 is disposed on the first wall 101 and is provided with a first weakened area 211; the insulating member 3 is disposed on the side of the first wall 101 facing the electrode assembly 103 of the battery cell, and the orthographic projection of the insulating member 3 on the first wall 101 covers the first weakened area 211.

[0078] The orthographic projection of the insulating member 3 on the first wall 101 covers the first weak area 211 , which means that the orthographic projection of the insulating member 3 on the first wall 101 completely covers the first weak area 211 , that is, no through-hole structure is provided on the insulating member 3 at a position corresponding to the first weak area 211 .

[0079] The first wall 101 is used to carry the pressure relief mechanism 2. Exemplarily, the battery cell 10 may also include an outer shell 1, which is used to enclose a relatively independent internal environment. The internal environment formed can be used to accommodate the electrode assembly 103, electrolyte (not shown in the figure) and other components. Exemplarily, the outer shell 1 can be a variety of structural forms, such as a cuboid, a cylinder, etc. Exemplarily, the shape of the outer shell 1 can be determined according to the specific shape of the electrode assembly 103. The material of the outer shell 1 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. Optionally, the first wall 101 can be any shell wall on the outer shell 1 of the battery.

[0080] For example, the housing 1 may include a shell 102 and an end cap. The shell 102 is a hollow structure with an opening on one side. The end cap is sealed against the opening of the shell 102 to form an internal environment for accommodating the electrode assembly 103 and the electrolyte. The end cap is provided with an electrode terminal 105 for extracting electrical energy. For ease of description, the following description assumes that the first wall 101 is the end cap.

[0081] The first weak zone 211 is the area on the pressure relief mechanism 2 that first ruptures when the internal pressure exceeds a threshold. For example, the first weak zone 211 can be a thinned area, or a pre-set area on the pressure relief mechanism 2 that has undergone material treatment, resulting in a weaker strength than other areas after the treatment. The material in the first weak zone 211 can have a lower melting point than other areas of the explosion-proof disk, allowing it to melt through and allow high-temperature gases to escape in the event of thermal runaway of the battery cell.

[0082] For example, the first weak area 211 may be an area on the pressure relief mechanism 2 that is about to be penetrated, such as a notch or groove on the explosion-proof disc 21 .

[0083] The insulating member 3 is used to insulate the first wall 101 from the electrode assembly 103. For example, the insulating member 3 can be a rubber plate or a plastic plate.

[0084] The electrode assembly 103 is the component within the battery cell where the electrochemical reaction occurs. For example, the electrode assembly 103 can be formed by winding or stacking a positive electrode sheet and a negative electrode sheet, typically with a separator between the positive and negative electrodes. The portions of the positive and negative electrodes containing active material form the main body of the electrode assembly 103, while the portions of the positive and negative electrodes without active material each form a tab. During the battery's charge and discharge processes, the positive and negative electrode active materials react with the electrolyte, forming a current loop connected to a power source or power-consuming device through the tabs.

[0085] By covering the first weak area 211 with the insulating part 3, the impact of the medium in the battery cell, such as the electrolyte, on the first weak area 211 can be reduced, the protective effect of the insulating part 3 on the first weak area 211 can be strengthened, the risk of the first weak area 211 being opened by the impact in non-emergency situations is reduced, and the battery safety is improved. For example, when the battery cell is inverted, the medium in the battery cell compresses the first weak area 211 under the action of gravity, causing the first weak area 211 to rupture and the pressure relief mechanism 2 to open. After the insulating part 3 is set to cover the first weak area 211, the insulating part 3 can effectively share the force pressing on the first weak area 211, that is, the compressive force on the first weak area 211 is reduced, thereby preventing the first weak area 211 from being crushed and causing the pressure relief mechanism 2 to open by mistake.

[0086] Alternatively, the pressure relief mechanism 2 may be a separately formed component, and the pressure relief mechanism 2 may be connected to the first wall 101 by welding, bonding, or other means. For example, a hole-like structure may be formed through the first wall 101, and the pressure relief mechanism 2 may be installed in and cover the hole-like structure to separate the space on both sides of the first wall 101. In an alternative embodiment, the pressure relief mechanism 2 and the first wall 101 may also be an integrally formed structure.

[0087] Optionally, the insulating member 3 may be entirely located between the pressure relief mechanism 2 and the electrode assembly 103 , or may be only partially located between the pressure relief mechanism 2 and the electrode assembly 103 .

[0088] 5 , the first weak area 211 can optionally be a closable annular structure, such as an annular notch. This allows for a larger passage area to be formed when the first weak area 211 ruptures, thereby improving pressure relief capabilities. In other embodiments, the first weak area 211 can also be an open annular notch or a plurality of intersecting notches.

[0089] FIG6 is a schematic diagram of a long-axis cross-sectional structure of the first wall 101 provided in some embodiments of the present application. FIG7 is a schematic diagram of a partial structure at point B in FIG6 . As shown in FIG4 to FIG7 , in some optional embodiments of the present application, the first wall 101 includes a pressure relief hole 104, the pressure relief mechanism 2 is a bursting disc 21, the bursting disc 21 seals the pressure relief hole 104, the bursting disc 21 is provided with a body 213 and a second weak area 214, the body 213 is connected to the first wall 101, the first weak area 211 is provided in the second weak area 214, the thickness of the first weak area 211 is less than the thickness of the second weak area 214, the thickness of the second weak area 214 is less than the thickness of the body 213, and the orthographic projection of the insulating member 3 on the first wall 101 covers the second weak area 214.

[0090] The orthographic projection of the insulating member 3 on the first wall 101 covers the second weak area 214 , which means that the orthographic projection of the insulating member 3 on the first wall 101 completely covers the second weak area 214 , that is, no through-hole structure is provided on the insulating member 3 at a position corresponding to the second weak area 214 .

[0091] By setting the pressure relief mechanism 2 as an explosion-proof plate 21, the structure on the first wall 101 can be simplified and the overall strength of the first wall 101 can be improved; secondly, by setting a second weak area 214 with a thickness greater than the first weak area 211 and less than the main body 213, the strength at the first weak area 211 can be reduced, which facilitates the first weak area 211 to be ruptured by impact, and also facilitates the second weak area 214 to follow the rupture when the first weak area 211 ruptures, thereby expanding the rupture range and improving the pressure relief capacity. Thirdly, by covering the second weak area 214 with the insulating part 3, the impact of the medium in the battery cell, such as the electrolyte, on the second weak area 214 can be reduced, thereby strengthening the protective effect of the insulating part 3 on the second weak area 214.

[0092] Optionally, the second weakened area 214 may be a thinned area on the bursting disk 21 .

[0093] Optionally, the bursting disc 21 may be further provided with reinforcing ribs 212 for reinforcing the overall strength of the bursting disc 21. Exemplarily, the reinforcing ribs 212 are provided within the area enclosed by the first weak area 211.

[0094] Figure 8 is a schematic diagram of the structure of the insulating member 3 provided in other embodiments of the present application. Figure 9 is a schematic diagram of the structure of the embodiment shown in Figure 8 from above, and Figure 10 is a schematic diagram of the short-axis cross-sectional structure of the first wall 101 provided in other embodiments of the present application. As shown in Figures 8, 9, and 10, in some optional embodiments of the present application, the insulating member 3 is provided with a through hole 32 extending through the thickness direction of the first wall 101 (the x-axis direction in the figure). The orthographic projection of the through hole 32 on the first wall 101 does not overlap with the first weak area 211.

[0095] By providing a through hole 32 that does not overlap with the first weak area 211, the insulating member 3 can ensure the protective effect of the first weak area 211. At the same time, in an emergency situation of the battery cell, such as thermal expansion of the battery cell, the high-temperature gas in the battery cell can quickly pass through the insulating member 3, and then impact the first weak area 211 to open the pressure relief mechanism 2, thereby improving the pressure relief response speed and enhancing the safety of the battery cell.

[0096] In some embodiments, when the first weak area 211 is an annular structure, the through hole 32 may be disposed outside the first weak area 211 , that is, the projection of the through hole 32 on the first wall 101 is located outside the first weak area 211 .

[0097] In some embodiments, the through hole 32 may be arranged outside the second weak area 214, that is, the projection of the through hole 32 on the first wall 101 is located outside the second weak area 214, so as to reduce the impact of the medium in the battery cell, such as electrolyte, on the first weak area 211 or the second weak area 214.

[0098] As shown in Figures 4, 8, 9 and 10, in some optional embodiments of the present application, the first wall 101 includes a pressure relief hole 104, the pressure relief mechanism 2 is an explosion-proof plate 21, the explosion-proof plate 21 closes the pressure relief hole 104, and the orthographic projection of the through hole 32 on the first wall 101 does not overlap with the explosion-proof plate 21.

[0099] By providing a through hole 32 that does not overlap with the explosion-proof plate 21, the protective effect of the insulating member 3 on the first weak area 211 can be improved, and the through hole 32 is arranged away from the area where the pressure relief mechanism 2 is located, thereby reducing the risk of the medium (such as electrolyte) in the battery cell passing through the insulating member 3 and impacting the first weak area 211 in non-emergency situations.

[0100] As shown in Figures 4, 8, 9 and 10, in some optional embodiments of the present application, the insulating member 3 includes a first area 31, the first area 31 is arranged corresponding to the area surrounded by the first weak area 211, and the through hole 32 is arranged around the first area 31.

[0101] The boundary of the orthographic projection of the first area 31 on the first wall 101 may be located outside the first weak area 211 or may coincide with the boundary of the first weak area 211 .

[0102] By arranging the through holes 32 around the first area 31 , the high-temperature gas in the battery cell can pass through the insulating member 3 and be closer to the first weak area 211 , so that in an emergency, the gas can impact the first weak area 211 and open the pressure relief mechanism 2 .

[0103] Optionally, the through hole 32 may be a square hole or a circular hole.

[0104] As shown in FIG. 4 , FIG. 8 , FIG. 9 and FIG. 10 , in some optional embodiments of the present application, a plurality of through holes 32 may be provided, and the plurality of through holes 32 are arranged at intervals around the first region 31 .

[0105] By arranging the through holes 32 at intervals around the first area 31 , a structure without through holes 32 exists around the first area 31 , which can improve the strength of the first area 31 and also enhance the protection of the insulating member 3 on the first weak area 211 .

[0106] Optionally, in a plane perpendicular to the thickness direction, the through hole 32 may conform to the outer contour of at least a portion of the first region 31 .

[0107] FIG11 is a schematic diagram of an orthographic projection of a first weak zone 211 on an insulating member 3, provided in some alternative embodiments of the present application. As shown in FIG8 to FIG11 , in some optional embodiments of the present application, the orthographic projection of the first weak zone 211 on the insulating member 3 includes an arcuate boundary 311. In the radial direction of the arcuate boundary 311, the minimum spacing between the through hole 32 and the arcuate boundary 311 is D1, and the radius of the arcuate boundary 311 is D2, satisfying the condition 0 ≤ D1 / D2 ≤ 1.

[0108] 11 , the boundary of the orthographic projection of the first area 31 on the first wall 101 coincides with the boundary of the first weak area 211 .

[0109] By constraining the range of D1 / D2, the range of the through hole 32 around the first weak area 211 can be constrained. On the one hand, it ensures that the high-temperature gas in the battery cell is close to the first weak area 211 after passing through the insulating part 3, thereby improving the response speed. On the other hand, it also prevents the high-temperature gas in the battery cell from being far away from the first weak area 211 after passing through the insulating part 3, resulting in the inability to quickly impact the first weak area 211 and causing the pressure relief mechanism 2 to open quickly.

[0110] Referring to Figure 11 , in some optional embodiments of the present application, the orthographic projection of the first weak zone 211 on the insulating member 3 may further include a straight boundary 312 connected to the arcuate boundary 311. In a direction perpendicular to the straight boundary 312, the minimum spacing between the hole wall of the through hole 32 and the straight boundary 312 is L1, satisfying that L1 equals D1. For example, two parallel straight boundaries 312 may be provided. In a direction perpendicular to the straight boundaries 312, the spacing between the two parallel straight boundaries 312 is L2, satisfying that 0 ≤ L1 / L2 ≤ 2. Optionally, L1 / L2 may be 0.1, 0.3, 0.5, 0.7, 0.9, 1, 1.3, 1.5, 1.7, or 1.9.

[0111] Optionally, the arc-shaped boundary 311 may be semicircular, and two arc-shaped boundaries 311 may be symmetrically provided, and the arc-shaped boundaries 311 on both sides may be connected by a straight boundary 312. For example, the boundary of the first zone may be in the shape of a circular racetrack.

[0112] Optionally, in the radial direction of the arcuate boundary 311, the minimum distance between the hole wall of the through hole 32 and the arcuate boundary 311 is D1, and the radius of the arcuate boundary 311 is D2, satisfying that D1 / D2 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9.

[0113] Optionally, when the arc-shaped boundary 311 coincides with the hole wall, D1 / D2 may be set to 0.

[0114] Figure 12 is a schematic diagram of the short-axis cross-section structure of the first wall provided in some further embodiments of the present application, Figure 13 is a schematic diagram of the structure of the insulating member 3 provided in some further embodiments of the present application, and Figure 14 is a schematic diagram of the bottom view of the embodiment shown in Figure 13. As shown in Figures 12 to 14, in some optional embodiments of the present application, the insulating member 3 is provided with a third weak area 33, which is designed to be destroyed in the event of thermal runaway of the battery cell, allowing gas to pass through the third weak area 33 and act on the first weak area 211.

[0115] By setting the third weak zone 33, on the one hand, the penetrating structure on the insulating member 3 can be reduced, further reducing the impact of the medium (such as electrolyte) in the battery cell on the first weak zone 211, and strengthening the protective effect of the insulating member 3 on the first weak zone 211. On the other hand, the third weak zone 33 can also be broken by the impact of the high-temperature gas in the battery cell in an emergency, thereby allowing the high-temperature gas in the battery cell to pass through and triggering the pressure relief process.

[0116] Optionally, the third weak zone 33 is the area on the insulating member 3 that first ruptures when the internal pressure exceeds a threshold. For example, the third weak zone 33 may be a region that has undergone a thickness reduction process; the third weak zone 33 may also be a pre-determined area on the insulating member 3 that has undergone material treatment, whereby the strength of the pre-determined area after material treatment is weaker than that of other areas; or the third weak zone 33 may be an area on the insulating member formed of a material with a lower melting point, which can be melted through to allow high-temperature gases to escape in the event of thermal runaway of the battery cell.

[0117] As shown in FIG. 12 to FIG. 14 , in some optional embodiments of the present application, the third weak area 33 includes a reduced thickness area 331 , and the thickness of the reduced thickness area 331 is less than the thickness of other areas on the insulating member 3 .

[0118] For example, a groove is formed on the insulating member 3 to form the reduced thickness area 331. Alternatively, the groove can be provided on a side of the insulating member 3 close to the first wall 101. Alternatively, the groove can be provided on a side of the insulating member 3 away from the first wall 101.

[0119] By providing the reduced thickness area 331 , the third weak area 331 can be easily broken by the impact of the high-temperature gas in the battery cell.

[0120] As shown in FIG. 12 , in some optional embodiments of the present application, the orthographic projection of the reduced thickness area on the first wall 101 at least partially overlaps with the first weak area 211 .

[0121] By providing a thickness reduction area that at least partially overlaps with the first weak area 211 , the high-temperature gas in the battery cell can impact and crush the thickness reduction area and directly correspond to the first weak area 211 , thereby increasing the pressure relief response speed and improving the safety of the battery cell.

[0122] FIG15 is a bottom view of the insulating member 3 provided in some other embodiments of the present application. Referring to FIG15 , optionally, the thinned thickness region may include multiple thinned thickness regions 331 , and the multiple thinned thickness regions 331 may be provided corresponding to the explosion-proof disks.

[0123] Optionally, the reduced thickness area may be annular and arranged around the orthographic projection of the first weak area 211 on the insulating member 3 .

[0124] As shown in Figures 12 to 14, in some optional embodiments of the present application, the thickness of the reduced thickness region is D3, and the insulating member 3 includes a second region 34 adjoining the reduced thickness region 331. The thickness of the second region 34 is D4, satisfying the condition 0 < D3 / D4 ≤ 0.8. By constraining the ratio D3 / D4 to a range of 0 to 0.8, the requirement that the reduced thickness region be easily ruptured to form a channel in an emergency can be met.

[0125] Alternatively, D3 / D4 may be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 or 0.7.

[0126] Figure 16 is a schematic diagram of a short-axis cross-sectional structure of the first wall provided in some further embodiments of the present application. As shown in Figure 16, in some optional embodiments of the present application, the insulating member 3 is provided with a through hole 32 extending through the thickness direction of the first wall 101 and a third weak zone 33. The orthographic projection of the through hole 32 on the first wall 101 does not overlap with the first weak zone 211.

[0127] By providing the through hole 32 , it is possible to facilitate high-temperature gas in the battery cell to pass through the insulating member 3 and impact the first weak area 211 , thereby increasing the pressure relief response speed and improving the safety of the battery cell.

[0128] In this embodiment, the through hole 32 may be provided on the third weak area 33 , or may be located outside the third thinned area 33 .

[0129] In some optional embodiments of the present application, a battery is provided, comprising the above-mentioned battery cell.

[0130] In some optional embodiments of the present application, an electrical device is provided, comprising the above-mentioned battery cell, for providing electrical energy.

[0131] In some optional embodiments of the present application, a battery cell is provided, comprising a first wall 101, a pressure relief mechanism 2, and an insulating member 3. The pressure relief mechanism 2 is disposed on the first wall 101 and has a first weakened area 211. The insulating member 3 is disposed on the side of the first wall 101 facing the electrode assembly 103 of the battery cell, with the orthographic projection of the insulating member 3 on the first wall 101 covering the first weakened area 211. The first wall 101 includes a pressure relief hole 104. The pressure relief mechanism 2 is a bursting disc 21, which seals the pressure relief hole 104. The bursting disc 21 has a body 213 and a second weakened area 214. The body 213 is connected to the first wall 101, and the first weakened area 211 is disposed in the second weakened area 214. The thickness of the first weakened area 211 is less than that of the second weakened area 214, which is less than that of the body 213. The orthographic projection of the insulating member 3 on the first wall 101 covers the second weakened area 214. The insulating member 3 is provided with a through hole 32 extending through the first wall 101 in the thickness direction. The orthographic projection of the through hole 32 on the first wall 101 does not overlap with the first weak zone 211. The insulating member 3 includes a first zone 31, which is arranged corresponding to the area enclosed by the first weak zone 211. The through hole 32 is arranged around the first zone 31. There may be multiple through holes 32, which are arranged at intervals around the first zone 31. The orthographic projection of the first weak zone 211 on the insulating member 3 includes an arcuate boundary 311. In the radial direction of the arcuate boundary 311, the minimum distance between the hole wall of the through hole 32 and the arcuate boundary 311 is D1, and the radius of the arcuate boundary 311 is D2, satisfying the following conditions: 0.6≤D1 / D2≤0.8.

[0132] Compared with the related art, in the battery cell, battery and electrical device of the embodiment of the present application, by covering the first weak area 211 with the insulating member 3, the impact of the medium in the battery cell, such as the electrolyte, on the first weak area 211 can be reduced, the protective effect of the insulating member 3 on the first weak area 211 is strengthened, the risk of the first weak area 211 being opened by the impact in non-emergency situations is reduced, and the battery safety is improved. For example, when the battery cell is inverted, the medium (such as the electrolyte) in the battery cell compresses the first weak area 211 under the action of gravity, causing the first weak area 211 to rupture and the pressure relief mechanism 2 to open. After the insulating member 3 is set to cover the first weak area 211, the insulating member 3 can effectively share the force pressing on the first weak area 211, that is, the compressive force on the first weak area 211 is reduced, thereby preventing the first weak area 211 from being crushed and causing the pressure relief mechanism 2 to open by mistake.

[0133] Although the present application has been described with reference to preferred embodiments, various modifications may be made thereto and components may be replaced with equivalents without departing from the scope of the present application. In particular, the various technical features described in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions within the scope of the claims.

Claims

1. A battery cell, comprising: First wall; a pressure relief mechanism, disposed on the first wall, the pressure relief mechanism having a first weak area; as well as An insulating member is provided on a side of the first wall facing the electrode assembly of the battery cell, and an orthographic projection of the insulating member on the first wall covers the first weak area.

2. The battery cell according to claim 1, wherein: The first wall includes a pressure relief hole, and the pressure relief mechanism is an explosion-proof disk. The explosion-proof disk closes the pressure relief hole. The explosion-proof disk is provided with a main body and a second weak area. The main body is connected to the first wall. The first weak area is arranged in the second weak area. The thickness of the first weak area is less than the thickness of the second weak area. The thickness of the second weak area is less than the thickness of the main body. The orthographic projection of the insulating member on the first wall covers the second weak area.

3. The battery cell according to claim 1 or 2, wherein: The insulating member is provided with a through hole penetrating along the thickness direction of the first wall, and the orthographic projection of the through hole on the first wall does not overlap with the first weak area.

4. The battery cell according to claim 3, wherein: The first wall includes a pressure relief hole, the pressure relief mechanism is a bursting disc, the bursting disc seals the pressure relief hole, and the orthographic projection of the through hole on the first wall does not overlap with the bursting disc.

5. The battery cell according to claim 3 or 4, wherein: The insulating member includes a first area, the first area is arranged corresponding to the area surrounded by the first weak area, and the through hole is arranged around the first area. The battery cell according to claim 5 , wherein: There may be a plurality of through holes, and the plurality of through holes are arranged at intervals around the first region.

7. The battery cell according to any one of claims 3 to 6, wherein: The orthographic projection of the first weak zone on the insulating member includes an arc-shaped boundary. In the radial direction of the arc-shaped boundary, the minimum distance between the through hole and the arc-shaped boundary is D1, and the radius of the arc-shaped boundary is D2, satisfying 0≤D1 / D2≤1.

8. The battery cell according to claim 1 or 2, wherein: The insulating member is provided with a third weak area, and the third weak area is configured to be destroyed when the battery cell thermally runs away, so that internal gas passes through the third weak area and acts on the first weak area.

9. The battery cell according to claim 8, wherein: The third weak area includes a reduced thickness area, and the thickness of the reduced thickness area is smaller than the thickness of other areas on the insulating member.

10. The battery cell according to claim 9, wherein: An orthographic projection of the reduced thickness area on the first wall at least partially overlaps with the first weakened area.

11. The battery cell according to any one of claims 8 to 10, wherein: The insulating member is provided with a through hole penetrating along the thickness direction of the first wall, and the orthographic projection of the through hole on the first wall does not overlap with the first weak area.

12. The battery cell according to any one of claims 9 to 11, wherein: The thickness of the reduced thickness area is D3, the insulating member includes a second area connected to the reduced thickness area, the thickness of the second area is D4, and 0<D3 / D4≤0.8 is satisfied.

13. A battery comprising the battery cell according to any one of claims 1 to 12.

14. An electrical device comprising the battery cell according to any one of claims 1 to 12, wherein the battery cell is used to provide electrical energy.

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