Battery monomer, battery and electric equipment

Abstract

The invention discloses a single battery, a battery and electric equipment, the single battery comprises a shell, a pressure relief part and an electrode assembly, in a first direction, the pressure relief part is arranged on a first side wall of the shell, the electrode assembly is arranged in the shell, in the first direction, the height of one part of the electrode assembly is smaller than that of the other part so as to define an avoidance space, and the pressure relief part is arranged on the first side wall of the shell; and the avoiding space is opposite to the pressure relief part. According to the single battery, the use safety of the battery can be improved, and the service life of the battery can be prolonged.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages of energy conservation and environmental protection. For electric vehicles, people are paying more and more attention to the safety of electric vehicles, among which battery technology is an important factor related to its development.

[0003] During use, the battery is prone to thermal runaway, which can lead to heat spread problems and affect the safety of battery use. Summary of the invention

[0004] In view of the above problems, the present application provides a battery cell that can improve the safety of battery use and extend the service life of the battery.

[0005] In a first aspect, the present application provides a battery cell, including: a shell, a pressure relief portion and an electrode assembly. In a first direction, the pressure relief portion is arranged on a first side wall of the shell, and the electrode assembly is arranged inside the shell. In the first direction, the height of a part of the electrode assembly is smaller than the height of the remaining part to define an avoidance space, and the avoidance space is arranged directly opposite to the pressure relief portion.

[0006] In the technical solution of the embodiment of the present application, an avoidance space is defined by limiting the heights of different parts of the electrode assembly in the first direction to be different, and the avoidance space is arranged opposite to the pressure relief portion, so that when the electrode assembly expands and deforms and causes the first side wall to deform in the early stage, the first side wall can be recessed in the direction of the avoidance space. In this way, the avoidance space can play a certain role in avoiding the deformation of the first side wall, thereby preventing the first side wall from abutting against the electrode assembly too early. Moreover, since the pressure relief portion is arranged on the first side wall, the avoidance space is arranged opposite to the pressure relief portion, that is, the avoidance space can play a role in avoiding the pressure relief portion, so that the pressure relief portion will not be pulled and cracked too early, thereby reducing the problem of heat spread in the battery, thereby improving the safety of battery use and extending the service life of the battery.

[0007] In some embodiments, in the first direction, the distance between the electrode assembly and the geometric center of the pressure relief portion is a first distance, the distance between the electrode assembly and the edge area of ​​the pressure relief portion is a second distance, and the first distance is greater than the second distance.

[0008] In the above technical solution, the distance between the geometric center of the electrode assembly and the pressure relief part is greater than the distance between the electrode assembly and the edge area of ​​the pressure relief part, so that the height of the avoidance space corresponding to the geometric center of the pressure relief part is higher. In this way, when the first side wall expands, it can avoid to a greater extent the geometric center of the pressure relief part from abutting against the electrode assembly too early, so that the pressure relief part will not be pulled and cracked too early, thereby reducing the problem of heat spread in the battery and further improving the safety of battery use.

[0009] In some embodiments, the distance between the electrode assembly and the pressure relief portion gradually increases in a direction toward a geometric center of the pressure relief portion.

[0010] In the above technical solution, the distance between the electrode assembly and the pressure relief portion is gradually increased in the direction toward the geometric center of the pressure relief portion, so that the shape of the avoidance space can better adapt to the expansion and deformation law of the first side wall at the pressure relief portion, thereby avoiding the pressure relief portion while reducing the impact on the volume energy density of the battery.

[0011] In some embodiments, the electrode assembly includes a positive electrode sheet and a negative electrode sheet stacked together. In the direction toward the geometric center of the pressure relief portion, the avoidance space includes multiple gradient areas, and the distances between the multiple gradient areas and the pressure relief portion gradually increase. Each gradient area includes at least two layers of negative electrode sheets.

[0012] In the above technical solution, by arranging in the direction toward the geometric center of the pressure relief portion, the distance between multiple gradient areas and the pressure relief portion gradually increases, so that the shape of the avoidance space can better adapt to the expansion and deformation law of the first side wall at the pressure relief portion, and each gradient area includes at least two layers of negative electrode sheets, which can reduce the impact of setting the avoidance space on the volume energy density of the battery.

[0013] In some embodiments, the number of negative electrode sheets in each gradient region is N, and the distance difference between two adjacent gradient regions and the pressure relief portion is H1, H1 = 2*D / (N-1), where D is the maximum distance between the avoidance space and the pressure relief portion.

[0014] In the above technical solution, by setting the relationship between the distance difference between two adjacent gradient areas and the pressure relief part and the number of layers of the negative electrode sheet in each gradient area, the avoidance space can reduce the impact on the volume energy density of the battery while avoiding the pressure relief part.

[0015] In some embodiments, the maximum distance between the avoidance space and the pressure relief portion is D, and in the first direction, the maximum height of the electrode assembly is H2, and satisfies: 1 / 20≤D / H2≤1 / 6.

[0016] In the above technical solution, when the maximum distance between the avoidance space and the pressure relief part and the maximum height of the electrode assembly satisfy the above proportional relationship, it is possible to avoid the pressure relief part in the avoidance space while reducing the impact on the volumetric energy density of the battery.

[0017] In some embodiments, the maximum distance D and the maximum height H2 satisfy 1 / 20 ≤ D / H2 ≤ 1 / 12.

[0018] In the above technical solution, by further limiting the proportional relationship between the maximum distance between the avoidance space and the pressure relief part and the maximum height of the electrode assembly, it is possible to avoid the pressure relief part in the avoidance space while reducing the impact on the volumetric energy density of the battery.

[0019] In some embodiments, the value range of the maximum distance D between the avoidance space and the pressure relief part is 5 - 15 mm.

[0020] In the above technical solution, when the maximum distance D between the avoidance space and the pressure relief part takes a value within the above value range, it is convenient for the avoidance space to avoid the pressure relief part while reducing the impact on the volumetric energy density of the battery.

[0021] In some embodiments, the height of the positive electrode sheet is less than the height of the negative electrode sheet, and the maximum distance D is the maximum distance between the negative electrode sheet in the avoidance space and the pressure relief part.

[0022] In the above technical solution, by defining the maximum distance between the negative electrode sheet and the pressure relief part as the maximum distance D between the avoidance space and the pressure relief part, the definition of the maximum distance D is made more accurate.

[0023] In some embodiments, the orthographic projection of the avoidance space on the first side wall covers the pressure relief part and a part of the first side wall.

[0024] In the above technical solution, through the above setting, a part of the avoidance space is disposed opposite to the part of the first side wall provided with the pressure relief part, so that the avoidance space can avoid the pressure relief part, so that the pressure relief part will not be prematurely pulled and cracked, thereby reducing the problem of thermal propagation of the battery and improving the use safety of the battery.

[0025] In some embodiments, the area of the orthographic projection of the avoidance space on the first side wall is S1, the area of the surface of the first side wall facing the electrode assembly is S2, and the ratio of S1 and S2 satisfies: 60% ≤ S1 / S2 ≤ 100%.

[0026] In the above technical solution, when the ratio of the area of the orthographic projection of the avoidance space on the first side wall to the area of the surface of the first side wall facing the electrode assembly satisfies the above proportional relationship, it is possible to avoid the pressure relief part in the avoidance space while reducing the impact on the volumetric energy density of the battery.

[0027] In some embodiments, the ratio satisfies: 60%≤S1 / S2≤80%.

[0028] In the above technical solution, by further limiting the ratio of the area of ​​the avoidance space's positive projection on the first side wall to the area of ​​the surface of the first side wall facing the electrode assembly, the avoidance space can reduce the impact on the volume energy density of the battery while avoiding the pressure relief part.

[0029] In some embodiments, in a width direction of the shell, the avoidance space extends from one end of the electrode assembly to the other end of the electrode assembly, and the width direction is respectively perpendicular to the first direction and the thickness direction of the shell.

[0030] In the above technical solution, the avoidance space is extended in the width direction of the shell so that the first side wall at different positions in the width direction of the shell can be deformed toward the avoidance space. In this way, the avoidance space can better avoid the deformation of the first side wall.

[0031] In some embodiments, the shell includes: a main body and a cover plate, the main body is provided with an opening, the cover plate is arranged at the opening to cover the opening, the electrode assembly is arranged in the main body, and the main body is provided with a first side wall.

[0032] In the above technical solution, an opening is provided in the main body so that the electrode assembly can be taken in and out through the opening, and a cover plate is provided so that the cover plate and the main body can protect the electrode assembly on the outside of the electrode assembly.

[0033] In some embodiments, the cover plate is provided with a pole, and the pole is electrically connected to the electrode assembly.

[0034] In the above technical solution, poles are provided so that the electric energy of the electrode assembly can be led out through the poles, thereby facilitating the input or output of the battery cell.

[0035] In some embodiments, the first side wall is used to support the electrode assembly and is located below the electrode assembly.

[0036] In the above technical solution, the first side wall is arranged below the electrode assembly, that is, the first side wall serves as the bottom wall of the battery cell, and the pressure relief portion is arranged on the bottom wall. In this way, when the electrode assembly expands and deforms and causes the first side wall to deform in the early stage, the first side wall can be recessed in the direction of the avoidance space. In this way, the avoidance space can play a certain avoidance role in the deformation of the first side wall, thereby preventing the first side wall from abutting against the electrode assembly too early. Moreover, since the pressure relief portion is arranged on the first side wall, the avoidance space is arranged opposite to the pressure relief portion, that is, the avoidance space can play a avoidance role for the pressure relief portion, so that the pressure relief portion will not be pulled and cracked too early, thereby reducing the problem of heat spread in the battery, and further improving the safety of battery use.

[0037] In a second aspect, the present application provides a battery, comprising a battery cell according to any one of the above embodiments.

[0038] In a third aspect, the present application provides an electrical device comprising the battery of the above embodiment.

[0039] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Moreover, the same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0041] Figure 1 A schematic diagram of the structure of a vehicle according to some embodiments of the present application;

[0042] Figure 2 An exploded schematic diagram of a battery according to some embodiments of the present application;

[0043] Figure 3 A perspective view of a battery cell according to some embodiments of the present application;

[0044] Figure 4 for Figure 3 A top view of a battery cell shown in ;

[0045] Figure 5 for Figure 4 Sectional view at AA in the middle;

[0046] Figure 6 for Figure 5 The enlarged view of point B in the middle;

[0047] Figure 7 Schematic diagram of an electrode assembly of some embodiments of the present application, which is a stack of positive and negative electrodes

[0048] Figure 8 The electrode assembly of other embodiments of the present application is a schematic diagram of a wound electrode sheet.

[0049] The reference numerals in the specific implementation manner are as follows:

[0050] Vehicles 1000;

[0051] Battery 100; battery cell 20; first direction F1; width direction F2; thickness direction F3; shell 1; first side wall 11; main body 12; cover plate 13; pole 131; pressure relief portion 2; electrode assembly 3; negative electrode sheet 311; positive electrode sheet 312; wound electrode sheet 32; pole ear 321; inner ring 322; outer ring 323; avoidance space 4; gradient area 41; first distance L1; second distance L2. DETAILED DESCRIPTION

[0052] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field 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" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0054] 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 relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0055] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0056] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0057] 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).

[0058] 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. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, which 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 referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the embodiments of the present application.

[0059] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship 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 the specific circumstances.

[0060] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0061] In the related art, a battery includes a battery cell. When a battery cell experiences thermal runaway, the electrode assembly inside the battery cell will generate heat and expand outward. In order to increase the volume energy density and weight energy density of the battery cell, the electrode assembly is usually directly against the shell. However, when the battery experiences thermal runaway, the expansion of the electrode assembly will squeeze the shell, causing the shell to rupture and causing heat spread, thereby reducing the safety of the battery.

[0062] In order to alleviate the problem of battery safety, a pressure relief portion can be provided on the shell in the related art. Specifically, the pressure in the shell is reduced by the rupture of the pressure relief portion, thereby reducing the heat spread problem caused by the rupture of the shell. However, the premature rupture of the pressure relief portion will reduce the service life of the battery, and the distance between the pressure relief portion of the bottom wall of the shell and the electrode assembly is usually closer than the distance between the pressure relief portion of the top of the shell, considering the energy density. When the shell is deformed by the expansion of the electrode assembly, it is easy to pull the bottom pressure relief portion to cause the pressure relief portion to crack. Through the analysis of the failure mechanism, the electrode assembly expands and pulls the bottom pressure relief portion in two stages: 1) The first stage, the early stage, when the electrode assembly expands outward, the pressure relief portion of the bottom wall of the shell is mainly concave upward; 2) The second stage, the pressure relief portion of the bottom wall of the shell is concave inward to contact the electrode assembly, and it cannot continue to be concave. After that, the bottom wall of the shell continues to bulge and deform, which will pull the pressure relief portion of the bottom wall laterally. Experimental verification has shown that the lateral pulling of the pressure relief portion on the bottom wall in the second stage is the main reason for the cracking of the pressure relief portion. If there is only the first stage in this process, that is, if only the pressure relief portion on the bottom wall of the shell is concave, the pressure relief portion will not crack.

[0063] Based on the above considerations, in order to solve the problem of safety during battery use and the problem that premature rupture of the pressure relief part will reduce the service life of the battery, the present application designs a battery cell, by arranging an avoidance space in the shell of the battery cell, and setting the avoidance space to be opposite to the pressure relief part, so that when the electrode assembly expands, the avoidance space can avoid the pressure relief part.

[0064] In such a battery cell, since the avoidance space is arranged opposite to the pressure relief portion, when the electrode assembly expands and deforms, causing the first side wall to deform in the early stage, the first side wall can be recessed in the direction of the avoidance space. In this way, the avoidance space can play a certain role in avoiding the deformation of the first side wall, thereby preventing the first side wall from abutting against the electrode assembly too early.

[0065] As the electrode assembly continues to expand, the avoidance space can avoid the pressure relief part, so that the pressure relief part will not be pulled and cracked prematurely, thereby reducing the problem of heat spread in the battery and further improving the safety and service life of the battery.

[0066] Against the background of increasing demand for battery energy density, the battery cell of the present application can make full use of the different heights of different areas of the electrode assembly in the first direction to define an avoidance space. Compared with reserving a bracket between the electrode assembly and the pressure relief portion, it can reduce the space occupied in the shell, thereby facilitating reducing the impact on the energy density of the battery.

[0067] The battery cell disclosed in the embodiment of the present application can be used in electrical equipment that uses the battery as a power source or various energy storage systems that use the battery as an energy storage element. Electrical equipment can be, but is not limited to, mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, electric toys can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0068] For the convenience of description, the following embodiments are described by taking a vehicle 1000 as an example of an electrical device in an embodiment of the present application.

[0069] Please refer to Figure 1 , Figure 1 A schematic diagram of the structure of a vehicle 1000 provided for some embodiments of the present application. 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 be used as an operating power source for the vehicle 1000. The vehicle 1000 may also include a controller and a motor, and the controller is used to control the battery 100 to power the motor, for example, for starting, navigating and driving the vehicle 1000.

[0070] In some embodiments of the present application, the battery 100 can not only serve as an operating power source for the vehicle 1000, but also serve 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.

[0071] Please refer to Figure 2 , Figure 2 An exploded view of a battery 100 provided for some embodiments of the present application. The battery 100 includes a case and a battery cell 20, and the battery cell 20 is contained in the case. Among them, the case is used to provide a storage space for the battery cell 20, and the case can adopt a variety of structures. In some embodiments, the case may include a first part and a second part, the first part and the second part cover each other, and the first part and the second part jointly define a storage space for accommodating the battery cell 20. The second part can be a hollow structure with an opening at one end, and the first part can be a plate-like structure, and the first part covers the open side of the second part, so that the first part and the second part jointly define a storage space; the first part and the second part can also be hollow structures with an opening on one side, and the open side of the first part covers the open side of the second part. Of course, the case formed by the first part and the second part can be a variety of shapes, such as a cylinder, a cuboid, etc.

[0072] In the battery 100, there can be multiple battery cells 20, and the multiple battery cells 20 can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 20 are both connected in series and in parallel. Multiple battery cells 20 can be directly connected in series, in parallel, or in mixed connection, and then the whole formed by the multiple battery cells 20 is accommodated in the box; of course, the battery 100 can also be a battery 100 module formed by multiple battery cells 20 connected in series, in parallel, or in mixed connection, and multiple battery 100 modules are then connected in series, in parallel, or in mixed connection to form a whole, and accommodated in the box. The battery 100 may also include other structures. For example, the battery 100 may also include a confluence component for realizing electrical connection between multiple battery cells 20.

[0073] Each battery cell 20 may be a secondary battery or a primary battery, or a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 may be cylindrical, flat, rectangular, or in other shapes.

[0074] The battery cell 20 refers to the smallest unit constituting the battery 100. The battery cell 20 includes an end cap, a housing 1, an electrode assembly 3 and other functional components.

[0075] The end cap refers to a component that covers the opening of the shell 1 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap can be adapted to the shape of the shell 1 to match the shell 1. Optionally, the end cap can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap is not easily deformed when squeezed and collided, so that the battery cell 20 can have a higher structural strength and the safety performance can also be improved. Functional components such as electrode terminals can be provided on the end cap. The electrode terminal can be used to electrically connect to the electrode assembly 3 for outputting or inputting electrical energy of the battery cell 20. In some embodiments, the end cap can also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. The material of the end cap can also be a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiments of the present application are not particularly limited to this. In some embodiments, an insulating member can also be provided on the inner side of the end cap, and the insulating member can be used to isolate the electrical connection components in the shell 1 from the end cap to reduce the risk of short circuit. For example, the insulating member may be plastic, rubber, or the like.

[0076] The shell 1 is a component used to cooperate with the end cap to form the internal environment of the battery cell 20, wherein the formed internal environment can be used to accommodate the electrode assembly 3, the electrolyte and other components. The shell 1 and the end cap can be independent components, and an opening can be set on the shell 1, and the internal environment of the battery cell 20 is formed by covering the opening with the end cap at the opening. Without limitation, the end cap and the shell 1 can also be integrated. Specifically, the end cap and the shell 1 can form a common connection surface before other components are put into the shell, and when the interior of the shell 1 needs to be encapsulated, the end cap is covered with the shell 1. The shell 1 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 1 can be determined according to the specific shape and size of the electrode assembly 3. The material of the shell 1 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0077] The electrode assembly 3 is a component in the battery cell 20 where an electrochemical reaction occurs. One or more electrode assemblies 3 may be included in the housing 1. The electrode assembly 3 is mainly formed by winding or stacking a positive electrode sheet 312 and a negative electrode sheet 311, and a separator is usually provided between the positive electrode sheet 312 and the negative electrode sheet 311. The parts of the positive electrode sheet 312 and the negative electrode sheet 311 with active materials constitute the main body of the electrode assembly 3, and the parts of the positive electrode sheet 312 and the negative electrode sheet 311 without active materials each constitute a tab 321. The positive tab 321 and the negative tab 321 may be located together at one end of the main body or at both ends of the main body respectively. During the charge and discharge process of the battery 100, the positive active material and the negative active material react with the electrolyte, and the tab 321 connects the electrode terminal to form a current loop.

[0078] According to some embodiments of the present application, referring to Figure 3 , and please refer to Figure 4-Figure 6 , Figure 3 A perspective view of a battery cell 20 according to some embodiments of the present application; Figure 4 for Figure 3 A top view of the battery cell 20 shown in FIG. Figure 5 for Figure 4 Sectional view at AA in the middle; Figure 6 for Figure 5 Enlarged view of point B in the middle.

[0079] An embodiment of the present application provides a battery cell 20, including: a shell 1, a pressure relief portion 2 and an electrode assembly 3. In a first direction F1, the pressure relief portion 2 is arranged on a first side wall 11 of the shell 1, and the electrode assembly 3 is arranged in the shell 1. In the first direction F1, the height of a part of the electrode assembly 3 is smaller than the height of the remaining part to define an avoidance space 4, and the avoidance space 4 is arranged opposite to the pressure relief portion 2.

[0080] like Figure 3 As shown in , the F1 direction in the figure is the first direction F1, that is, the height direction of the electrode assembly 3.

[0081] “The height of a portion of the electrode assembly 3 in the first direction F1 is less than the height of the remaining portion” includes the left portion of the electrode assembly 3 (such as Figure 6 The height of the left part in the first direction F1 is smaller than that of the right part (such as Figure 6 The height of the right part of the electrode assembly 3 in the first direction F1 is less than the height of the left part, or the height of the middle part of the electrode assembly 3 in the first direction F1 is less than the height of the left part and / or the right part, which is not limited here.

[0082] The “pressure relief portion 2 ” includes but is not limited to providing an explosion-proof valve, or thinning a local area of ​​the first side wall 11 , or providing notches, indentations, etc. to achieve pressure relief.

[0083] The electrode assembly 3 is arranged in the shell 1 so that the shell 1 can protect the electrode assembly 3, and the height of a part of the electrode assembly 3 in the first direction F1 is smaller than the height of the remaining parts to define an escape space 4, that is, different parts of the electrode assembly 3 have different heights in the first direction F1 to define the escape space 4, and the escape space 4 is arranged opposite to the pressure relief part 2.

[0084] Among them, the avoidance space 4 is defined by limiting the different heights of different parts of the electrode assembly 3 in the first direction F1. Compared with the solution of setting a bracket at the corresponding position of the pressure relief part 2 inside the shell 1 to define the avoidance space 4, the setting method of the avoidance space 4 in the present application is simpler and helps to reduce the impact on the energy density of the battery cell 20.

[0085] In this way, in the early stage of the deformation of the first side wall 11 caused by the expansion and deformation of the electrode assembly 3, the first side wall 11 can be recessed in the direction of the avoidance space 4. In this way, the avoidance space 4 can play a certain avoidance role in the deformation of the first side wall 11, thereby preventing the first side wall 11 from abutting against the electrode assembly 3 too early. Moreover, since the pressure relief portion 2 is arranged on the first side wall 11, the avoidance space 4 is arranged opposite to the pressure relief portion 2, that is, the avoidance space 4 can play a avoidance role for the pressure relief portion 2, so that the pressure relief portion 2 will not be pulled and cracked too early, thereby reducing the problem of heat spread in the battery 100, thereby improving the safety of the battery 100 and extending the service life of the battery cell 100.

[0086] According to some embodiments of the present application, optionally, please refer to Figure 6, in the first direction F1, the distance between the electrode assembly 3 and the geometric center of the pressure relief portion 2 is the first distance L1, and the distance between the electrode assembly 3 and the edge region of the pressure relief portion 2 is the second distance L2, and the first distance L1 is greater than the second distance L2.

[0087] Thereby, the height of the avoidance space 4 corresponding to the geometric center of the pressure relief portion 2 is higher. In this way, when the first side wall 11 expands, it can more effectively prevent the geometric center of the pressure relief portion 2 from coming into contact with the electrode assembly 3 prematurely, so that the pressure relief portion 2 will not be prematurely pulled and cracked, thereby reducing the problem of thermal propagation in the battery 100 and improving the use safety of the battery 100.

[0088] According to some embodiments of the present application, optionally, in the direction towards the geometric center of the pressure relief portion 2 (for example Figure 6 the directions of the left and right sides in towards the geometric center of the pressure relief portion 2), the distance between the electrode assembly 3 and the pressure relief portion 2 gradually increases.

[0089] Thereby, by setting the distance between the electrode assembly 3 and the pressure relief portion 2 to gradually increase in the direction towards the geometric center of the pressure relief portion 2, the shape of the avoidance space 4 can better adapt to the expansion deformation law of the first side wall 11 at the pressure relief portion 2, so as to play a role in avoiding the pressure relief portion 2 while reducing the impact on the volumetric energy density of the battery 100.

[0090] According to some embodiments of the present application, optionally, please refer to Figure 7 , the electrode assembly 3 includes a positive electrode sheet 312 and a negative electrode sheet 311 stacked, and the separator is located between the positive electrode sheet 312 and the negative electrode sheet 311. In the direction towards the geometric center of the pressure relief portion 2, the avoidance space 4 includes a plurality of gradient regions 41, and the distance between the plurality of gradient regions 41 and the pressure relief portion 2 gradually increases, and each gradient region 41 includes at least two layers of negative electrode sheets 311.

[0091] Thereby, the electrode assembly 3 is configured as a laminated electrode formed by laminating the positive electrode sheet 312 and the negative electrode sheet 311. Optionally, a separator can be provided between the positive electrode sheet 312 and the negative electrode sheet 311 to play an insulating role between the positive electrode sheet 312 and the negative electrode sheet 311.

[0092] Furthermore, in the direction toward the geometric center of the pressure relief portion 2, the avoidance space 4 includes a plurality of gradient regions 41, and the distance between the plurality of gradient regions 41 and the pressure relief portion 2 gradually increases, so that the shape of the avoidance space 4 can better adapt to the expansion and deformation law of the first side wall 11 at the pressure relief portion 2, wherein each gradient region 41 includes at least two layers of negative electrode sheets 311, that is, the plurality of gradient regions 41 are two-layer (two layers of negative electrode sheets 311) gradients, which can reduce the difficulty of setting compared to a single-layer (one layer of negative electrode sheet 311) gradient, and is beneficial to reducing the influence of setting the avoidance space 4 on the volume energy density of the battery 100.

[0093] According to some embodiments of the present application, optionally, the number of layers of the negative electrode sheets 311 in each gradient region 41 is N, and the distance difference between two adjacent gradient regions 41 and the pressure relief portion 2 is H1, H1=2*D / (N-1), and D is the maximum distance between the avoidance space 4 and the pressure relief portion 2.

[0094] “D is the maximum distance between the avoidance space 4 and the pressure relief portion 2 ”, that is, D is the same as the first distance L1 in the above embodiment.

[0095] “The distance difference between two adjacent gradual change areas 41 and the pressure relief portion 2 is H1 ” refers to the difference between the distance between one of the two adjacent gradual change areas 41 and the pressure relief portion 2 and the distance between the other gradual change area 41 and the pressure relief portion 2 .

[0096] Among them, the units of H1 and D are both mm. Therefore, by setting the relationship between the distance difference between two adjacent gradient areas 41 and the pressure relief part 2 and the number of layers of the negative electrode sheet 311 in each gradient area 41, the avoidance space 4 can avoid the pressure relief part 2 while reducing the impact on the volume energy density of the battery 100.

[0097] According to other embodiments of the present application, optionally, please refer to Figure 8 The electrode assembly 3 can be constructed as a wound pole piece 32, the wound pole piece 32 is a whole pole piece, and the height difference between the electrode assembly 3 and the pressure relief portion 2 is completed when the whole pole piece is die-cut. The wound pole piece 32 is provided with a pole ear 321, and is divided into an inner ring 322 and an outer ring 323 in the length direction of the pole piece during die-cutting. The width of the inner ring 322 is narrower than that of the outer ring 323 on the non-pole ear 321 side by 0-15mm. When the pole piece is wound, the inner ring 322 is wound first, and the outer ring 323 is wound last, so that the inner rings are narrower in the height direction.

[0098] According to some embodiments of the present application, optionally, the maximum distance between the avoidance space 4 and the pressure relief portion 2 is D, and in the first direction F1, the maximum height of the electrode assembly 3 is H2, and satisfies: 1 / 20≤D / H2≤1 / 6.

[0099] For example, D / H2=1 / 7, or D / H2=1 / 6, or D / H2=1 / 8, that is, when the maximum distance between the avoidance space 4 and the pressure relief portion 2 and the maximum height of the electrode assembly 3 satisfy the above-mentioned proportional relationship, the avoidance space 4 can avoid the pressure relief portion 2 while reducing the impact on the volume energy density of the battery 100.

[0100] According to some embodiments of the present application, optionally, the maximum distance D and the maximum height H2 satisfy 1 / 20≤D / H2≤1 / 12.

[0101] That is, the proportional relationship between the maximum distance D and the maximum height H2 is further limited, for example, D / H2=1 / 12, or D / H2=1 / 15, or D / H2=1 / 15. When the proportional relationship between the maximum distance D and the maximum height H2 satisfies the above-mentioned proportional range, the avoidance space 4 can avoid the pressure relief part 2 while reducing the impact on the volume energy density of the battery 100.

[0102] According to some embodiments of the present application, optionally, a maximum distance D between the avoidance space 4 and the pressure relief portion 2 ranges from 5 to 15 mm.

[0103] For example, the maximum distance D between the avoidance space 4 and the pressure relief portion 2 is 6 mm, or 8 mm, or 12 mm, or 14.5 mm, etc. When the maximum distance D between the avoidance space 4 and the pressure relief portion 2 is within the above-mentioned value range, the avoidance space 4 can avoid the pressure relief portion 2 while reducing the impact on the volume energy density of the battery 100.

[0104] According to some embodiments of the present application, optionally, the height of the positive electrode sheet 312 is smaller than the height of the negative electrode sheet 311 , and the maximum distance D is the maximum distance between the negative electrode sheet 311 and the pressure relief portion 2 in the avoidance space 4 .

[0105] Therefore, by limiting the maximum distance between the negative electrode sheet 311 and the pressure relief portion 2 to the maximum distance D between the avoidance space 4 and the pressure relief portion 2 , the maximum distance D can be more accurately defined.

[0106] According to some embodiments of the present application, optionally, the orthographic projection of the avoidance space 4 on the first side wall 11 covers the pressure relief portion 2 and a portion of the first side wall 11 .

[0107] As a result, a portion of the avoidance space 4 is arranged opposite to the portion of the first side wall 11 where the pressure relief portion 2 is provided, so that the avoidance space 4 can avoid the pressure relief portion 2, so that the pressure relief portion 2 will not be pulled and cracked prematurely, thereby reducing the problem of heat spread in the battery 100 and further improving the safety of the battery 100.

[0108] According to some embodiments of the present application, optionally, the area of ​​the avoidance space 4 on the first side wall 11 is S1, the area of ​​the surface of the first side wall 11 facing the electrode assembly 3 is S2, and the ratio of S1 to S2 satisfies: 60%≤S1 / S2≤100%

[0109] For example, S1 / S2=60%, or 70%, or 90%. When the ratio of the area of ​​the positive projection of the avoidance space 4 on the first side wall 11 to the area of ​​the surface of the first side wall 11 facing the electrode assembly 2 satisfies the above-mentioned proportional relationship, the avoidance space 4 can avoid the pressure relief part 2 while reducing the impact on the volume energy density of the battery cell 20.

[0110] According to some embodiments of the present application, optionally, the ratio satisfies: 60%≤S1 / S2≤80%.

[0111] For example, S1 / S2=60%, or 70%, or 75%, that is, by further limiting the ratio of the area of ​​the positive projection of the avoidance space 4 on the first side wall 11 to the area of ​​the surface of the first side wall 11 facing the electrode assembly 3, the avoidance space 4 can avoid the pressure relief portion 2 while reducing the impact on the volume energy density of the battery cell 20.

[0112] According to some embodiments of the present application, optionally, please refer to Figure 6 In the width direction F2 of the shell 1, the avoidance space 4 extends from one end of the electrode assembly 3 to the other end of the electrode assembly 3, and the width direction F2 is perpendicular to the first direction F1 and the thickness direction F3 of the shell 1.

[0113] Therefore, by setting the avoidance space 4 extending in the width direction F2 of the shell 1, the first side wall 11 at different positions in the width direction F2 of the shell 1 can be recessed and deformed toward the avoidance space 4, so that the avoidance space 4 can better avoid the deformation of the first side wall 11.

[0114] According to some embodiments of the present application, optionally, please refer to Figure 3 The shell 1 includes: a main body 12 and a cover plate 13 . The main body 12 is provided with an opening. The cover plate 13 is provided at the opening to cover the opening. The electrode assembly 3 is provided in the main body 12 . The main body 12 is provided with a first side wall 11 .

[0115] Therefore, an opening is provided in the main body 12 so that the electrode assembly 3 can be taken in and out through the opening, and a cover plate 13 is provided so that the cover plate 13 and the main body 12 can protect the electrode assembly 3 on the outside of the electrode assembly 3 .

[0116] According to some embodiments of the present application, optionally, please refer to Figure 3The cover plate 13 is provided with a pole 131 , and the pole 131 is electrically connected to the electrode assembly 3 .

[0117] Therefore, by providing the pole 131 , it is convenient to lead out the electric energy of the electrode assembly 3 through the pole 131 , and it is convenient for the battery cell 20 to input or output electric energy.

[0118] According to some embodiments of the present application, optionally, please refer to Figure 3 The first side wall 11 is used to support the electrode assembly 3 and is located below the electrode assembly 3 .

[0119] It should be noted that the bottom wall of the shell 1 is usually the side wall supported by the battery cell 20 and the supporting surface, and the first side wall 11 is used to support the electrode assembly 3 and is located below the electrode assembly 3, that is, the first side wall 11 is the bottom wall. In this way, when the electrode assembly 3 is affected by its own gravity, the pressure relief part 2 is arranged on the bottom wall, so that the distance between the pressure relief part 2 and the electrode assembly 3 is closer, so as to improve the energy density of the battery cell 20.

[0120] Therefore, by constructing the first side wall 11 as the bottom wall, that is, the pressure relief portion 2 is arranged on the bottom wall, so that the interference between the pressure relief portion 2 and the pole 131 can be avoided, which is conducive to reducing the difficulty of its arrangement, and the pressure relief portion 2 is arranged on the bottom wall so that when the electrode assembly 3 expands and deforms and causes the first side wall 11 to deform in the early stage, the first side wall 11 can be recessed in the direction of the avoidance space 4, so that the deformation of the first side wall 11 can be avoided to a certain extent by the avoidance space 4, so as to avoid the first side wall 11 from abutting against the electrode assembly 3 too early, and because the pressure relief portion 2 is arranged on the first side wall 11, the avoidance space 4 is arranged opposite to the pressure relief portion 2, that is, the avoidance space 4 can avoid the pressure relief portion 2, so that the pressure relief portion 2 will not be pulled and cracked too early, thereby reducing the problem of heat spread in the battery 100, thereby improving the safety of the battery 100, and at the same time, it is conducive to reducing the impact on the energy density of the battery cell 20.

[0121] In a second aspect, the present application provides a battery 100 including a battery cell 20 according to any one of the above embodiments.

[0122] In a third aspect, the present application provides an electrical device, which includes the battery 100 of the above embodiment.

[0123] According to some embodiments of the present application, the battery cell 20 includes: a shell 1, a pressure relief portion 2 and an electrode assembly 3. In the first direction F1, the pressure relief portion 2 is arranged on the first side wall 11 of the shell 1, and the electrode assembly 3 is arranged in the shell 1. In the first direction F1, the height of a part of the electrode assembly 3 is smaller than the height of the remaining part to define an avoidance space 4, and the avoidance space 4 is arranged opposite to the pressure relief portion 2. Therefore, the avoidance space 4 is defined by limiting the different heights of different parts of the electrode assembly 3 in the first direction F1, and the avoidance space 4 is arranged opposite to the pressure relief portion 2, so that when the electrode assembly 3 expands and deforms to cause the first side wall 11 to deform in the early stage, the first side wall 11 can be recessed toward the direction of the avoidance space 4. In this way, the avoidance space 4 can play a certain role in avoiding the deformation of the first side wall 11, thereby preventing the first side wall 11 from abutting against the electrode assembly 3 too early. Moreover, since the pressure relief portion 2 is arranged on the first side wall 11, the avoidance space 4 is arranged opposite to the pressure relief portion 2, that is, the avoidance space 4 can play a role in avoiding the pressure relief portion 2, so that the pressure relief portion 2 will not be pulled and cracked too early, thereby reducing the problem of heat spread in the battery 100, and further improving the safety of the battery 100.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A battery cell, It is characterized in that include: case; A pressure relief portion, in a first direction, the pressure relief portion is disposed on a first side wall of the housing; The electrode assembly is arranged in the shell, and in the first direction, the height of a part of the electrode assembly is smaller than the height of the remaining part to define an escape space, and the escape space is arranged opposite to the pressure relief part.

2. The battery cell according to claim 1, It is characterized in that In the first direction, the distance between the electrode assembly and the geometric center of the pressure relief portion is a first distance, and the distance between the electrode assembly and the edge area of ​​the pressure relief portion is a second distance, and the first distance is greater than the second distance.

3. The battery cell according to claim 2, It is characterized in that In a direction toward a geometric center of the pressure relief portion, a distance between the electrode assembly and the pressure relief portion gradually increases.

4. The battery cell according to claim 3, It is characterized in that The electrode assembly includes a positive electrode sheet and a negative electrode sheet stacked together. In the direction toward the geometric center of the pressure relief portion, the avoidance space includes a plurality of gradient regions, and the distances between the plurality of gradient regions and the pressure relief portion gradually increase. Each of the gradient regions includes at least two layers of the negative electrode sheets.

5. The battery cell according to claim 4, It is characterized in that The number of layers of the negative electrode sheets in each gradient region is N, and the distance difference between two adjacent gradient regions and the pressure relief portion is H1, wherein H1=2*D / (N-1), and D is the maximum distance between the avoidance space and the pressure relief portion.

6. The battery cell according to claim 1, It is characterized in that The maximum distance between the avoidance space and the pressure relief portion is D. In the first direction, the maximum height of the electrode assembly is H2, and the following relationship is satisfied: 1 / 20≤D / H2≤1 / 6.

7. The battery cell according to claim 6, It is characterized in that The maximum distance D and the maximum height H2 satisfy 1 / 20≤D / H2≤1 / 12.

8. The battery cell according to claim 1, It is characterized in that The maximum distance D between the avoidance space and the pressure relief portion ranges from 5 to 15 mm.

9. The battery cell according to claim 5, It is characterized in that The height of the positive electrode sheet is smaller than the height of the negative electrode sheet, and the maximum distance D is the maximum distance between the negative electrode sheet and the pressure relief portion in the avoidance space.

10. The battery cell according to any one of claims 1 to 9, It is characterized in that The orthographic projection of the escape space on the first side wall covers the pressure relief portion and a portion of the first side wall.

11. The battery cell according to claim 10, It is characterized in that The area of ​​the orthographic projection of the avoidance space on the first side wall is S1, the area of ​​the surface of the first side wall facing the electrode assembly is S2, and the ratio of S1 to S2 satisfies: 60%≤S1 / S2≤100%.

12. The battery cell according to claim 11, It is characterized in that The ratio satisfies: 60%≤S1 / S2≤80%.

13. The battery cell according to claim 10, It is characterized in that In a width direction of the shell, the avoidance space extends from one end of the electrode assembly to the other end of the electrode assembly, and the width direction is respectively perpendicular to the first direction and the thickness direction of the shell.

14. The battery cell according to claim 1, It is characterized in that The housing comprises: A main body and a cover plate, wherein the main body is provided with an opening, the cover plate is arranged at the opening to cover the opening, the electrode assembly is arranged in the main body, and the main body is provided with the first side wall.

15. The battery cell according to claim 14, It is characterized in that The cover plate is provided with a pole, and the pole is electrically connected to the electrode assembly.

16. The battery cell according to claim 14, It is characterized in that The first side wall is used to support the electrode assembly and is located below the electrode assembly.

17. A battery, It is characterized in that The invention comprises a battery cell according to any one of claims 1 to 16.

18. An electrical device, It is characterized in that Comprising a battery according to claim 17.

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