WO2024026825A1

WO2024026825A1 - Battery cell, battery and electrical apparatus

Info

Publication number: WO2024026825A1
Application number: PCT/CN2022/110520
Authority: WO
Inventors: 杨开焕; 周文林; 李全坤; 柯海波; 梅祥
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-08-05
Filing date: 2022-08-05
Publication date: 2024-02-08

Abstract

Provided in the embodiments of the present application are a battery cell, a battery and an electrical apparatus. The battery cell comprises a first wall, a pressure relief mechanism and an insulation member. The pressure relief mechanism is arranged on the first wall, and the pressure relief mechanism is provided with a first vulnerable area. The insulation member is arranged on the side of the first wall facing an electrode assembly of the battery cell, and the orthographic projection of the insulation member on the first wall covers the first vulnerable area. By covering the first vulnerable area with the insulation member, the impact of a medium in the battery cell, such as an electrolyte, on the first vulnerable area can be alleviated, such that the protection effect of the insulation member on the first vulnerable area is improved, and the risk that the first vulnerable area is broken by impact under non-emergency conditions is reduced, thereby improving the safety of batteries.

Description

Battery cells, batteries and electrical devices

Technical field

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 technique

As the consumption of natural resources and environmental damage become increasingly severe, interest in devices that can store energy and effectively utilize the stored energy is growing in various fields. Battery cells are systems that can be combined with each other to harness new renewable energy.

In the field of battery equipment technology, the pressure relief mechanism usually installed on the battery cell shell can connect the inside and outside of the battery when the battery cell is thermally out of control. However, if it is opened in non-emergency situations, it will seriously affect the battery cell. body safety.

Application content

Embodiments of the present application provide a battery cell, a battery and an electrical device, which can reduce the pressure relief mechanism from being opened when the battery cell is in normal use, thereby improving the safety of the battery.

A first aspect of the embodiment of the present application provides a battery cell, including a first wall, a pressure relief mechanism and an insulator. The pressure relief mechanism is provided on the first wall, and the pressure relief mechanism is provided with a first weak area; the insulating member is provided on a side of the first wall facing the electrode assembly of the battery cell, and the An orthographic projection of the insulating element on the first wall covers the first weak zone.

Using the above structure, by covering the first weak area with the insulating member, 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 member on the first weak area can be strengthened, and non-emergency In this case, the risk of the first weak zone being opened by impact improves the safety of the battery. For example, when the battery cell is turned upside down, the medium in the battery cell presses the first weak zone under the action of gravity, causing the first weak zone to rupture and release the pressure. The mechanism is turned on, and after the insulating member is installed to cover the first weak area, the insulating member can effectively share the force pressing on the first weak area, that is, the pressing force on the first weak area is reduced, thereby preventing the first weak area. It was crushed and ruptured, causing the pressure relief mechanism to open accidentally.

In some optional embodiments of the present application, the first wall includes a pressure relief hole, the pressure relief mechanism is an explosion-proof disc, the explosion-proof disc closes the pressure relief hole, and the explosion-proof disc is provided with a body and a third Two weak areas, the body is connected to the first wall, the first weak area is provided in the second weak area, the thickness of the first weak area is smaller than the thickness of the second weak area, the The thickness of the second weak zone is smaller than the thickness of the body, and the orthographic projection of the insulating member on the first wall covers the second weak zone.

Using the above structure, by setting the pressure relief mechanism as an explosion-proof disc, 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 zone with a thickness greater than the first weak zone and smaller than the body, It can reduce the strength of the first weak zone, making it easier for the first weak zone to be ruptured by impact. It is also convenient for the second weak zone to follow the rupture when the first weak zone ruptures, expanding the rupture range and improving the pressure relief capability. Thirdly, by The insulating member covers the second weak area, which can reduce the impact of the medium in the battery cell, such as electrolyte, on the second weak area, and strengthen the protective effect of the insulating member on the second weak area.

In some optional embodiments of the present application, 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 is consistent with the The first weak areas do not overlap.

Using the above structure, by arranging through holes that do not overlap with the first weak area, it is possible to ensure that the insulating member protects the first weak area, and at the same time, it is convenient for the battery cells to be removed in emergency situations, such as when the battery cells are thermally out of control and generate a large amount of gas. The gas in the battery cell can quickly pass through the insulator, and then impact the first weak area to open the pressure relief mechanism, improving the pressure relief response speed and improving the safety of the battery cell.

In some optional embodiments of the present application, the first wall includes a pressure relief hole, the pressure relief mechanism is an explosion-proof disc, the explosion-proof disc closes the pressure relief hole, and the through hole is in the first The orthographic projection on the wall does not overlap the explosion disk.

Using the above structure, by arranging a through hole that does not overlap with the explosion-proof disc, the protective effect of the insulating member on the first weak zone can be improved, so that the through hole can be set away from the area where the pressure relief mechanism is located, and the medium in the battery cell can be reduced in non-emergency situations. Risk of impact through the insulation to the first weak zone.

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. .

Using the above structure, by arranging the through holes around the first area, the high-temperature gas in the battery cell can be closer to the first weak area after passing through the insulating member, so that in an emergency, it can impact the first weak area to activate the pressure relief mechanism. Open.

In some optional implementations 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 section.

Using the above structure, by arranging the through holes at intervals around the first area, there is a structure without through holes on the peripheral side of the first area, which can improve the strength of the first area and also improve the protection of the first weak area by the insulating member. effect.

In some optional implementations of the present application, the orthographic projection of the first weak zone on the insulating member includes an arc-shaped boundary, and in the radial direction of the arc-shaped boundary, the through hole and the arc-shaped boundary The minimum distance between boundaries is D1, and the radius of the arc-shaped boundary is D2, satisfying 0≤D1/D2≤1.

Using the above structure, by constraining the D1/D2 range, the range of the through hole on the peripheral side of the first weak zone can be restricted. On the one hand, it is ensured that the high-temperature gas in the battery cell is closer to the first weak zone after passing through the insulator. , to improve the response speed. On the other hand, it also prevents the high-temperature gas in the battery cell from passing through the insulator and being far away from the first weak zone, resulting in the inability to quickly impact the first weak zone and causing the pressure relief mechanism to quickly open.

In some optional embodiments of the present application, the insulator is provided with a third weak zone, and the third weak zone is used to be destroyed when the battery cell is thermally out of control, so that gas can pass through the third weak zone. Three weak areas act on the first weak area.

Using the above structure, by setting up the third weak zone, on the one hand, it can reduce the penetration structure on the insulating member, further reduce the impact of the medium (such as electrolyte) in the battery cell on the first weak zone, and strengthen the impact of the insulating member on the first weak zone. On the other hand, the third weak zone can also be impacted and broken by the high-temperature gas in the battery cell in an emergency, allowing the high-temperature gas in the battery cell to pass through and trigger the pressure relief process.

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

Using the above structure, by setting the thickness reduction area, the third weak area can be easily broken by the impact of high-temperature gas in the battery cell.

In some optional implementations of the present application, an orthographic projection of the thickness reduction zone on the first wall at least partially overlaps the first weak zone.

Using the above structure, by arranging a thinned area that at least partially overlaps with the first weak area, the high-temperature gas in the battery cell can directly correspond to the first weak area after impacting and breaking the thinned area, thereby improving the pressure relief response. speed and improve the safety of battery cells.

Adopting the above structure and providing through holes can facilitate the high-temperature gas in the battery cell to pass through the insulating member and impact the first weak zone, thereby improving the pressure relief response speed and improving the safety of the battery cell.

In some optional embodiments of the present application, the thickness at the thinned area is D3, and the insulating member includes a second area connected to the thinned area, and the thickness of the second area is D4, satisfies, 0<D3/D4≤0.8.

Using the above structure, by constraining the ratio of D3/D4 to a range of 0 to 0.8, it can meet the needs of the thickness reduction area that is prone to breakage to form a channel in an emergency.

A second aspect of the embodiment of the present application provides a battery, including the above-mentioned battery cell.

A third aspect of the embodiment of the present application provides an electrical device, including the above-mentioned battery cell, where the battery cell is used to provide electric energy.

Compared with related technologies, in the battery cells, batteries and electrical devices of the embodiments of the present application, by covering the first weak area with an insulating member, the impact of the medium in the battery cell, such as electrolyte, on the first weak area can be reduced. impact, strengthen the protective effect of the insulating parts on the first weak zone, reduce the risk of the first weak zone being opened by impact in non-emergency situations, and improve battery safety. For example, when the battery cell is inverted, the medium in the battery cell will be under gravity Under the action, the first weak zone is pressed, causing the first weak zone to rupture, and the pressure relief mechanism is opened. After the insulating part is set to cover the first weak zone, the insulating part can effectively share the force pressing on the first weak zone, that is, the pressure is reduced. The pressure on the first weak zone is reduced, thereby preventing the first weak zone from being crushed and causing the pressure relief mechanism to open accidentally.

Description of the drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments of the present application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. Those of ordinary skill in the art can also obtain other drawings based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a vehicle provided by some embodiments of the present application.

Figure 2 is a schematic structural diagram of a battery provided by some embodiments of the present application.

Figure 3 is a schematic structural diagram of a battery cell provided by some embodiments of the present application.

Figure 4 is a schematic structural diagram of the first wall provided by some embodiments of the present application.

Figure 5 is a schematic structural diagram of an explosion-proof disc provided by some embodiments of the present application.

Figure 6 is a schematic structural diagram of a long axis cross-section of the first wall provided by some embodiments of the present application.

Figure 7 is a schematic diagram of the partial structure at B in Figure 6.

Figure 8 is a schematic structural diagram of an insulator provided by other embodiments of the present application.

FIG. 9 is a schematic structural view from below of the embodiment shown in FIG. 8 .

Figure 10 is a short-axis cross-sectional structural diagram of the first wall provided by other embodiments of the present application.

Figure 11 is a schematic orthographic view of the first weak zone on the insulating member provided by other embodiments of the present application.

Figure 12 is a schematic structural diagram of a short-axis cross-section of the first wall provided in some embodiments of the present application.

Figure 13 is a schematic structural diagram of an insulating member provided by some further embodiments of the present application.

FIG. 14 is a schematic structural view from below of the embodiment shown in FIG. 13 .

Figure 15 is a schematic bottom view of an insulating member provided in some embodiments of the present application.

Figure 16 is a schematic structural diagram of the short-axis cross-section of the first wall provided by some embodiments of the present application.

In the drawings: 1000, vehicle; 100, battery; 200, controller; 300, motor; 110, box; 111, first box part; 112, second box part; 1, shell; 101, first Wall; 102. Shell; 103. Electrode assembly; 104. Pressure relief hole; 105. Electrode terminal; 2. Pressure relief mechanism; 21. Explosion-proof disc; 211. First weak zone; 212. Reinforcement rib; 213. Body; 214. The second weak zone; 3. Insulating parts; 31. The first zone; 311. Arc-shaped boundary; 312. Straight-line boundary; 32. Through holes; 33. The third weak zone; 331. Thickness reduction zone; 34. District 2.

Detailed ways

The implementation of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present application more clearly, and are therefore only used as examples and cannot be used to limit the protection scope of the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the technical field belonging to this application; the terms used herein are for the purpose of describing specific embodiments only and are not intended to be used in Limitation of this application; the terms "including" and "having" and any variations thereof in the description and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion.

In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying the relative importance or implicitly indicating the quantity or specificity of the indicated technical features. Sequence or priority relationship.

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 appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art understand, both explicitly and implicitly, that the embodiments described herein may be combined with other embodiments.

In the description of the embodiments of this application, the term "and/or" is only an association relationship describing associated objects, indicating that there can be three relationships, such as A and/or B, which can mean: A exists alone, and A exists simultaneously and B, there are three cases of B alone. In addition, the character "/" in this article generally indicates that the related objects are an "or" relationship.

In the description of the embodiments of this application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to It is more than two pieces (including two pieces).

In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right" and "vertical" The orientation or positional relationships indicated by "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on those shown in the accompanying drawings. The orientation or positional relationship is only to facilitate the description of the embodiments of the present application and to simplify the description. It does 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 cannot be understood as a limitation of the implementation of the present application. method restrictions.

In the description of the embodiments of the present application, unless otherwise explicitly stipulated and limited, technical terms such as "installation", "connection", "connection" and "fixing" should be understood in a broad sense. For example, it can be a fixed connection or a removable connection. It can be disassembled and connected, or integrated; it can also be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be an internal connection between two elements or an interaction between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

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, etc. The embodiments of this application are not limited to this. . The battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped or other shapes, and the embodiments of the present application are not limited to this. The battery cells may be hard-shell battery cells, soft-pack battery cells or other types of battery cells.

The battery cell includes electrode components and electrolyte. Exemplarily, the electrode assembly includes a positive electrode piece, a negative electrode piece, and a separator. Battery cells mainly rely on the movement of metal ions between the positive and negative electrodes to work. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode current collector includes a positive electrode current collector and a positive electrode tab. The positive electrode current collector is coated with the positive electrode active material layer. , the positive electrode tab is not coated with the positive electrode active material layer. Taking a lithium-ion battery cell as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material layer includes a positive electrode active material. The positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganate, etc. The negative electrode piece includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode current collector includes a negative electrode current collector and a negative electrode tab. The negative electrode current collector is coated with the negative electrode active material layer. , the negative electrode tab is not coated with the negative electrode active material layer. The material of the negative electrode current collector may be copper, the negative electrode active material layer may include a negative electrode active material, and the negative electrode active material may be carbon or silicon. The material of the isolator can be PP (polypropylene, polypropylene) or PE (polyethylene, polyethylene), etc.

The battery mentioned in the embodiments of this application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. Batteries generally include a box for packaging one or more battery cells. The box can prevent liquid or other foreign matter from affecting the charging or discharging of the battery cells.

The development of battery technology must consider 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 also needs to be considered.

The pressure relief mechanism on the battery cell has an important impact on the safety of the battery cell. For example, when short circuit, overcharge, etc. occur, thermal runaway may occur inside the battery cell and the pressure may rise suddenly. In this case, the internal pressure can be released outward by actuating the pressure relief mechanism to prevent the battery cells from exploding or catching fire.

The pressure relief mechanism may be an element or component that is activated when the battery cells reach certain conditions. Illustratively, the pressure relief mechanism may be an element or component that is actuated to relieve the internal pressure and/or internal contents when the internal pressure or internal temperature of the battery cell reaches a predetermined threshold. This threshold design varies based on design requirements. This threshold may depend on one or more materials of the positive electrode tab, negative electrode tab, electrolyte and separator in the battery cell.

The pressure relief mechanism can take the form of an explosion-proof valve, an air valve, a pressure relief valve or a safety valve, etc., and can specifically adopt a pressure-sensitive element or structure. That is, when the internal pressure of the battery cell reaches a predetermined threshold, the pressure relief mechanism executes The weak area provided in the action or pressure relief mechanism ruptures, thereby forming a pressure relief channel for internal pressure relief. Alternatively, the pressure relief mechanism may also adopt a temperature-sensitive element or structure, that is, when the internal temperature of the battery cell reaches a predetermined threshold, the pressure relief mechanism takes action, thereby forming a pressure relief channel for the internal pressure to be released. Alternatively, the pressure relief mechanism may also be an actively actuable component. For example, the pressure relief mechanism may be actuated upon receiving a control signal from the battery.

The pressure relief mechanism can also take other forms. For example, the pressure relief mechanism may be a lower-strength structure on the outer casing of the battery cell. When the battery cell is thermally out of control, the lower-strength structure cracks or deforms to form a pressure relief channel for internal pressure relief. . For example, the pressure relief mechanism can be a welding mark on the casing of the battery cell.

The “actuation” mentioned in this application means that the pressure relief mechanism acts or is activated to a certain state, thereby allowing the internal pressure and/or internal materials of the battery cells to be released. The actions generated by the pressure relief mechanism may include, but are not limited to: at least a portion of the pressure relief mechanism is ruptured, broken, torn or opened, etc. When the pressure relief mechanism is actuated, high-temperature and high-speed substances inside the battery cells will be discharged outward from the actuated part as emissions. In this way, the battery cells can be depressurized under controllable pressure, thereby avoiding potentially more serious accidents.

The inventor noticed that the triggering condition of the pressure relief mechanism is actually that the pressure acting on the pressure relief mechanism exceeds the threshold, and the medium in the battery's internal environment has fluid properties, so the pressure in the battery's internal environment may be different everywhere, which leads to Under normal use conditions of the battery (such as the battery being placed upside down or on its side, so that the pressure relief mechanism is located at the bottom of the battery in the direction of gravity), the pressure relief mechanism may be opened due to the large local pressure at the pressure relief mechanism. Cause an accident, but reduce the safety of the battery.

In order to alleviate the problem of low battery safety, the inventor found that the structure of the pressure relief mechanism can be adjusted and the pressure relief mechanism can be appropriately blocked, so that under normal use, the bearing force on the pressure relief mechanism can be reduced and leakage can be reduced. The risk of accidentally opening the pressing mechanism is eliminated, effectively improving the safety of the battery.

Based on the above considerations, the inventor of the present application designed a battery cell, a battery and a power device after in-depth research.

Embodiments of the present application provide an electrical device that uses a battery as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric vehicle, a ship, a spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, spaceships, etc.

For the convenience of explanation in the following embodiments, an electric device 1000 according to an embodiment of the present application is used as an example.

Figure 1 is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application. As shown in Figure 1, the vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or a range-extended vehicle. The battery 100 is disposed inside the vehicle 1000 , and the battery 100 may be disposed 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 also include a controller 200 and a motor 300 . The controller 200 is used to control the battery 100 to provide power to the motor 300 , for example, for starting, navigating and driving the vehicle 1000 .

In some embodiments of the present application, the battery 100 can not only be used as an operating power source for the vehicle 1000 , but also can be used 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 .

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

Figure 2 is a schematic structural diagram of a battery 100 provided by some embodiments of the present application. As shown in Figure 2, in some embodiments of the present application, the battery 100 includes a box 110. The box 110 may include a connected first box part 111 and a second box part 112, and multiple battery cells are connected in parallel. Either in series or in mixed combination, they are placed in the space formed by connecting the first box part 111 and the second box part 112. The shapes of the first box part 111 and the second box part 112 can be based on the shape of multiple battery cells. The shape formed by the combination of bodies is determined. The battery cell may be in the shape of a cylinder, a flat body, a rectangular parallelepiped, or other shapes, which are not limited in the embodiments of the present application. The packaging methods of the battery cells include but are not limited to cylindrical battery cells, rectangular battery cells, soft-pack battery cells, etc., and the embodiments of the present application are not specifically limited to this. In addition, the battery 100 may also include other structures, such as bus components, for realizing electrical connections between multiple battery cells, which will not be described in detail here.

Figure 3 is a schematic structural diagram of a battery cell provided by some embodiments of the present application. Figure 4 is a schematic structural diagram of the first wall 101 provided by some embodiments of the present application. Figure 5 is a schematic structural diagram of the explosion-proof disc 21 provided by some embodiments of the present application. Schematic. As shown in FIGS. 3 to 5 , in some embodiments of the present application, a battery cell 10 is provided, including a first wall 101 , a pressure relief mechanism 2 and an insulator 3 . The pressure relief mechanism 2 is provided on the first wall 101, and the pressure relief mechanism 2 is provided with a first weak area 211; the insulating member 3 is provided on the side of the first wall 101 facing the electrode assembly 103 of the battery cell, and the insulating member 3 is on the first wall 101. The orthographic projection on one wall 101 covers the first weak area 211 .

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 to say, the insulating member 3 No through-hole structure is provided at the position corresponding to the first weak area 211.

The first wall 101 is used to carry the pressure relief mechanism 2 . Exemplarily, the battery cell 10 may also include a casing 1, which is used to enclose and form a relatively independent internal environment. The formed internal environment may be used to accommodate the electrode assembly 103 and the electrolyte (not shown in the figure). and other components. For example, the housing 1 can be in various structural forms, such as rectangular parallelepiped, cylinder, etc. For example, the shape of the housing 1 may be determined according to the specific shape of the electrode assembly 103 . The housing 1 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. Alternatively, the first wall 101 may be any wall on the housing 1 of the battery.

For example, the housing 1 may include a housing 102 and an end cover. The housing 102 is a hollow structure with one side open. The end cover covers the opening of the housing 102 and forms a sealed connection to form a structure for accommodating the electrode assembly 103 and the internal environment of the electrolyte. The end cap is provided with electrode terminals 105 for extracting electrical energy. For convenience of explanation, the first wall 101 is used as an end cap for description below.

The first weak area 211 is the area on the pressure relief mechanism 2 that first breaks when the pressure of the internal environment exceeds the threshold. For example, the first weak area 211 can be a thinned area; it can also be a preset area where material treatment is performed on the pressure relief mechanism 2, and the strength of the preset area after material treatment is weaker than the strength of other areas. ; The melting point of the material at the first weak area 211 can be lower than that of other areas of the explosion-proof disc. When the battery cell is thermally out of control, this area can melt through and allow high-temperature gas to escape.

For example, the first weak area 211 may be an area on the pressure relief mechanism 2 that will be penetrated, such as a score or a groove on the explosion-proof disc 21 .

The insulating member 3 is used to insulate the first wall 101 and the electrode assembly 103 . For example, the insulating member 3 may be a rubber plate or a plastic plate.

The electrode assembly 103 is a component used in the battery cell for electrochemical reactions to occur. For example, the electrode assembly 103 may be formed by winding or stacking positive electrode sheets and negative electrode sheets, and usually a separator is provided between the positive electrode sheets and the negative electrode sheets. The portions of the positive electrode sheet and the negative electrode sheet that contain active material constitute the main body of the electrode assembly 103, and the portions of the positive electrode sheet and the negative electrode sheet that do not contain active material each constitute tabs. During the charging and discharging process of the battery, the positive active material and negative active material react with the electrolyte, and are connected to the power supply or electrical device through the tabs to form a current loop.

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 can be strengthened, and the impact of the insulating member 3 on the first weak area 211 can be reduced. The risk of the first weak zone 211 being opened by impact in an emergency improves battery safety. For example, when a battery cell is inverted, the medium in the battery cell compresses the first weak zone 211 under the action of gravity, causing the first weak zone 211 rupture, the pressure relief mechanism 2 is opened, and after the insulating member 3 is installed 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 pressure on the first weak area 211 is reduced. The compressive force prevents the first weak area 211 from being crushed and causing the pressure relief mechanism 2 to open accidentally.

Alternatively, the pressure relief mechanism 2 may be an independently formed component, and the pressure relief mechanism 2 and the first wall 101 may be connected by welding, bonding or other means. For example, a hole-like structure is provided through the first wall 101 , and the pressure relief mechanism 2 is installed and covered on the hole-like structure to separate the spaces on both sides of the first wall 101 . In alternative embodiments, the pressure relief mechanism 2 and the first wall 101 may also be an integrally formed structure.

Alternatively, 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 .

Referring to FIG. 5 , optionally, the first weak area 211 can be a closeable annular structure, for example, the first weak area 211 can be an annular notch. This facilitates the formation of a larger passing area when the first weak zone 211 ruptures, thereby improving the pressure relief capability; in other embodiments, the first weak zone 211 may also be an unclosed annular score or a plurality of cross-set score.

Figure 6 is a schematic structural diagram of the long axis cross-section of the first wall 101 provided by some embodiments of the present application. Figure 7 is a schematic diagram of the partial structure at B in Figure 6. As shown in Figures 4 to 7, 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 disc 21, the explosion-proof disc 21 closes the pressure relief hole 104, and the explosion-proof disc 21 closes the pressure relief hole 104. 21 is provided with a body 213 and a second weak zone 214. The body 213 is connected to the first wall 101. The first weak zone 211 is provided in the second weak zone 214. The thickness of the first weak zone 211 is smaller than the thickness of the second weak zone 214. The thickness of the second weak zone 214 is smaller 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 zone 214 .

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 to say, the insulating member 3 No through hole structure is provided at the position corresponding to the second weak area 214 .

By arranging the pressure relief mechanism 2 as an explosion-proof disc 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 arranging a second weak area with a thickness greater than the first weak area 211 and smaller than the body 213 Zone 214 can reduce the strength of the first weak zone 211, making it easier for the first weak zone 211 to be ruptured by impact. It is also convenient for the second weak zone 214 to follow the rupture when the first weak zone 211 ruptures, expanding the rupture range and improving pressure relief. Thirdly, by covering the second weak area 214 with the insulating member 3, the impact of the medium in the battery cell, such as the electrolyte, on the second weak area 214 can be reduced, and the impact of the insulating member 3 on the second weak area 214 can be reduced. Protective effects.

Optionally, the second weak area 214 may be a thinned area on the explosion-proof disc 21 .

Optionally, the explosion-proof disc 21 may also be provided with reinforcing ribs 212 to enhance the overall strength of the explosion-proof disc 21 . For example, the reinforcing ribs 212 are provided in the area enclosed by the first weak zone 211 .

Figure 8 is a schematic structural diagram of the insulating member 3 provided by other embodiments of the present application. FIG. 9 is a schematic structural view from below of the embodiment shown in FIG. 8 , and FIG. 10 is a schematic short-axis cross-sectional structural view of the first wall 101 provided by other embodiments of the present application. As shown in FIGS. 8 , 9 and 10 , in some optional embodiments of the present application, the insulating member 3 is provided with a through hole 32 penetrating along 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 .

By arranging the through hole 32 that does not overlap with the first weak area 211, it is possible to ensure the protective effect of the insulating member 3 on the first weak area 211, and at the same time, it is convenient for the battery cell to protect the battery cell in case of emergency, such as thermal expansion of the battery cell. The high-temperature gas can quickly pass through the insulator 3 and then impact the first weak area 211 to open the pressure relief mechanism 2, thereby improving the pressure relief response speed and improving the safety of the battery cells.

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

In some embodiments, the through hole 32 can be disposed 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 to reduce the medium in the battery cell. Such as the impact of electrolyte on the first weak area 211 or the second weak area 214.

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 disc 21, and the explosion-proof disc 21 seals the leakage. The orthographic projections of the pressure hole 104 and the through hole 32 on the first wall 101 do not overlap with the explosion-proof disc 21 .

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

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, and the first area 31 corresponds to the area surrounded by the first weak area 211. Arranged, the through hole 32 is arranged around the first area 31 .

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 .

By arranging the through holes 32 around the first area 31, the high-temperature gas in the battery cell can be closer to the first weak area 211 after passing through the insulating member 3, so that in an emergency, it can impact the first weak area 211 to relieve the pressure. Institution 2 opens.

Alternatively, the through hole 32 may be a square hole or a circular hole, or the like.

As shown in FIGS. 4 , 8 , 9 and 10 , in some optional embodiments of the present application, multiple through holes 32 may be provided, and the multiple through holes 32 are arranged at intervals around the first region 31 .

By arranging the through holes 32 at intervals around the first area 31, there is a structure without the through holes 32 on the peripheral side of the first area 31, which can improve the strength of the first area 31 and also improve the resistance of the insulating member 3 to the first weak point. Zone 211 protection.

Alternatively, in a plane perpendicular to the thickness direction, the through hole 32 may conform to at least part of the outer contour of the first region 31 .

FIG. 11 is a schematic orthographic view of the first weak zone 211 on the insulating member 3 provided by other embodiments of the present application. As shown in FIGS. 8 to 11 , in some optional embodiments of the present application, the orthographic projection of the first weak zone 211 on the insulator 3 includes an arc-shaped boundary 311 , and in the radial direction of the arc-shaped boundary 311 , the through hole The minimum distance between 32 and the arc-shaped boundary 311 is D1, and the radius of the arc-shaped boundary 311 is D2, which satisfies, 0≤D1/D2≤1.

Referring to FIG. 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 .

By constraining the range of D1/D2, the range of the through hole 32 on the peripheral side of the first weak zone 211 can be restricted. On the one hand, it is ensured that the high-temperature gas in the battery cell is closer to the first weak zone 211 after passing through the insulator 3 , improve the response speed, on the other hand, it also prevents the high-temperature gas in the battery cell from passing through the insulator 3 and being far away from the first weak area 211, resulting in the inability to quickly impact the first weak area 211, so that the pressure relief mechanism 2 can quickly open .

Referring to FIG. 11 , in some optional embodiments of the present application, the orthographic projection of the first weak zone 211 on the insulator 3 may also include a straight boundary 312 connected to the arc boundary 311 , in a direction perpendicular to the straight boundary 312 On, the minimum distance between the hole wall of the through hole 32 and the linear boundary 312 is L1, which satisfies that L1 is equal to D1. For example, two straight-line boundaries 312 may be provided in parallel. In the direction perpendicular to the straight-line boundaries 312, the distance between the two parallel straight-line boundaries 312 is L2, which satisfies 0≤L1/L2≤2. Alternatively, L1/L2 can be 0.1, 0.3, 0.5, 0.7, 0.9, 1, 1.3, 1.5, 1.7 or 1.9.

Optionally, the arcuate borders 311 may be semicircular, and two arcuate borders 311 may be symmetrically provided, and the arcuate borders 311 on both sides may be connected by straight lines 312 . For example, the boundary of the first zone may be in the shape of a circular racetrack.

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

Optionally, when the arc-shaped boundary 311 coincides with the hole wall, D1/D2 can be taken as 0.

Figure 12 is a schematic structural diagram of the short-axis cross-section of the first wall provided in some embodiments of the present application. Figure 13 is a schematic structural diagram of the insulating member 3 provided in some further embodiments of the present application. Figure 14 is a schematic diagram of the embodiment shown in Figure 13 Schematic diagram of the structure looking up. 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. The third weak area 33 is used to be destroyed when the battery cell is thermally out of control, so that the The gas passes through the third weak zone 33 and acts on the first weak zone 211.

By providing the third weak area 33, on the one hand, the penetration 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 area 211, and strengthening the impact of the insulating member 3 on the first weak area 211. In addition to the protective effect of the weak zone 211, on the other hand, the third weak zone 33 can also be impacted and broken by the high-temperature gas in the battery cell in an emergency, thereby allowing the high-temperature gas in the battery cell to pass through, triggering the pressure relief process.

Optionally, the third weak zone 33 is the area on the insulating member 3 that first breaks when the pressure of the internal environment exceeds a threshold. For example, the third weak area 33 may be a thickness reduction area; the third weak area 33 may also be a preset area where material treatment is performed on the insulating member 3, and the strength of the preset area after material treatment is weak. The third weak area 33 can also be an area formed of a material with a lower melting point on the insulating member. When the battery cell is thermally out of control, this area can be melted through to allow high-temperature gas to escape.

As shown in FIGS. 12 to 14 , in some optional embodiments of the present application, the third weak area 33 includes a thickness reduction area 331 , and the thickness of the thickness reduction area 331 is smaller than the thickness of other areas on the insulating member 3 .

For example, the thickness reduction area 331 is formed by making grooves on the insulating member 3 . Alternatively, the groove may be provided on a side of the insulating member 3 close to the first wall 101 . Alternatively, the groove may be provided on the side of the insulating member 3 away from the first wall 101 .

By providing the thinned area 331, the third weak area 331 can be easily broken by the impact of high-temperature gas in the battery cell.

As shown in FIG. 12 , in some optional implementations of the present application, the orthographic projection of the thickness reduction zone on the first wall 101 at least partially overlaps the first weak zone 211 .

By providing a thinned area that at least partially overlaps the first weak area 211, the high-temperature gas in the battery cell can directly correspond to the first weak area 211 after impacting and breaking the thinned area, thereby improving the pressure relief response speed. Improve the safety of battery cells.

Figure 15 is a schematic bottom structural view of the insulating member 3 provided in other embodiments of the present application. Referring to FIG. 15 , optionally, the thickness reduction zone may include multiple thickness reduction zones 331 , and multiple thickness reduction zones 331 may be provided corresponding to the explosion-proof disc.

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

As shown in Figures 12 to 14, in some optional embodiments of the present application, the thickness at the thinned area is D3, and the insulating member 3 includes a second area 34 connected to the thinned area 331. The thickness of area 34 is D4, which satisfies 0<D3/D4≤0.8. By constraining the ratio of D3/D4 to a range of 0 to 0.8, it is possible to meet the requirement that the thickness thinning area is prone to breakage to form a channel in an emergency.

Alternatively, D3/D4 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 or 0.7.

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

By providing the through hole 32 , the high-temperature gas in the battery cell can pass through the insulator 3 and impact the first weak zone 211 , thereby improving the pressure relief response speed and improving the safety of the battery cell.

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

In some optional embodiments of the present application, a battery is provided, including the above-mentioned battery cell.

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

In some optional embodiments of the present application, a battery cell is provided, including a first wall 101 , a pressure relief mechanism 2 and an insulator 3 . The pressure relief mechanism 2 is provided on the first wall 101, and the pressure relief mechanism 2 is provided with a first weak area 211; the insulating member 3 is provided on the side of the first wall 101 facing the electrode assembly 103 of the battery cell, and the insulating member 3 is on the first wall 101. The orthographic projection on one wall 101 covers the first weak area 211 . The first wall 101 includes a pressure relief hole 104. The pressure relief mechanism 2 is an explosion-proof disc 21. The explosion-proof disc 21 closes the pressure relief hole 104. The explosion-proof 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 disposed in the second weak area 214. The thickness of the first weak area 211 is smaller than the thickness of the second weak area 214. The thickness of the second weak area 214 is smaller than the thickness of the body 213. The insulating member 3 is on the first wall. The orthographic projection on 101 covers the second weak zone 214. The insulating member 3 is provided with a through hole 32 penetrating along the thickness direction of the first wall 101 , and the orthographic projection of the through hole 32 on the first wall 101 does not overlap with the first weak area 211 . The insulating member 3 includes a first area 31 , which 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 . A plurality of through holes 32 may be provided, and the plurality of through holes 32 are arranged at intervals around the first area 31 . The orthographic projection of the first weak zone 211 on the insulating member 3 includes an arc-shaped boundary 311. In the radial direction of the arc-shaped boundary 311, the minimum distance between the hole wall of the through hole 32 and the arc-shaped boundary 311 is D1. The arc-shaped boundary The radius of 311 is D2, which satisfies 0.6≤D1/D2≤0.8.

Compared with the related art, in the battery cells, batteries and electrical devices of the embodiments of the present application, by covering the first weak area 211 with the insulating member 3, it is possible to reduce the impact of the medium in the battery cell, such as electrolyte, on the first weak area 211. The impact of the weak area 211 strengthens the protective effect of the insulating member 3 on the first weak area 211, reduces the risk of the first weak area 211 being opened by impact in non-emergency situations, and improves battery safety. For example, when the battery cell is inverted, the battery cell The medium (such as electrolyte) in the body presses the first weak area 211 under the action of gravity, causing the first weak area 211 to rupture, and the pressure relief mechanism 2 is opened. After the insulating member 3 is installed to cover the first weak area 211, the insulation The component 3 can effectively share the force pressing on the first weak area 211, that is, reducing the pressing force on the first weak area 211, thereby preventing the first weak area 211 from being crushed and causing the pressure relief mechanism 2 to open accidentally.

Although the application has been described with reference to preferred embodiments, various modifications may be made and equivalents may be substituted for parts thereof without departing from the scope of the application, in particular provided that no structural conflicts exist , the technical features mentioned in each embodiment can be combined in any way. The application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

A battery cell including:

first wall;

A pressure relief mechanism is provided on the first wall, and the pressure relief mechanism is provided with a first weak zone; and

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.
The battery cell according to claim 1, wherein the first wall includes a pressure relief hole, the pressure relief mechanism is an explosion-proof disc, the explosion-proof disc closes the pressure relief hole, and the explosion-proof disc is provided with a body and a second weak zone, the body is connected to the first wall, the first weak zone is provided in the second weak zone, the thickness of the first weak zone is smaller than the thickness of the second weak zone, The thickness of the second weak zone is smaller than the thickness of the body, and the orthographic projection of the insulating member on the first wall covers the second weak zone.
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 through hole is located directly on the first wall. The projection does not overlap the first weak area.
The battery cell according to claim 3, wherein the first wall includes a pressure relief hole, the pressure relief mechanism is an explosion-proof disc, the explosion-proof disc closes the pressure relief hole, and the through hole is in the The orthographic projection on the first wall does not overlap with the explosion-proof disc.
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 surrounds the First zone settings.
The battery cell according to claim 5, wherein a plurality of through holes can be provided, and a plurality of the through holes are arranged at intervals around the first section.
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, and in the radial direction of the arc-shaped boundary, the 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.
The battery cell according to claim 1 or 2, wherein the insulating member is provided with a third weak zone, the third weak zone is used to be destroyed when the battery cell is thermally runaway, so that the internal gas The first weak zone is acted upon through the third weak zone.
The battery cell according to claim 8, wherein the third weak area includes a thickness reduction area, and the thickness of the thickness reduction area is smaller than the thickness of other areas on the insulating member.
The battery cell of claim 9, wherein an orthographic projection of the thickness-thinning region on the first wall at least partially overlaps the first weak region.
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 through hole is formed on the first wall. The orthographic projection on does not overlap with the first weak zone.
The battery cell according to any one of claims 9 to 11, wherein the thickness of the thinned area is D3, the insulating member includes a second area connected to the thinned area, and the The thickness of the second area is D4, which satisfies 0<D3/D4≤0.8.
A battery including the battery cell according to any one of claims 1-12.
An electrical device, including the battery cell according to any one of claims 1 to 12, wherein the battery cell is used to provide electrical energy.