Batteries and electrical devices

Abstract

The present application relates to the technical field of batteries, and in particular to a battery and an electrical device. The battery includes a plurality of battery cells arranged in a certain direction, the battery cell includes an electrode assembly and a shell, the electrode assembly is placed in the shell, and the plurality of battery cells include a first battery cell and a second battery cell, the first battery cell and the second battery cell are configured so that when the number of electrical cycles of the battery is greater than or equal to 100 times, the full charge group margin of the first battery cell is less than 1, and the full charge group margin of the second battery cell is greater than 1; the full charge group margin refers to the ratio of the maximum size of the electrode assembly to the minimum size of the shell along the arrangement direction of the plurality of battery cells when the battery cell is in a fully charged state. In view of the above problems, the battery provided in the embodiment of the present application can reduce the overall external expansion force of the plurality of battery cells, prevent the battery cells from causing extrusion damage to other components of the battery, and improve the electrical connection stability and safety of the battery.

Description

Technical Field

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

[0002] The battery cell includes an electrode assembly and a shell. The shell has a accommodating cavity. The electrode assembly is installed in the accommodating cavity. During the charge and discharge process, the electrode assembly will expand, thereby making the electrode assembly have a certain expansion force. The expansion force acts on the shell, causing the shell to bulge outward.

[0003] When a battery contains a large number of battery cells, the total expansion amount of the multiple battery cells when they swell simultaneously will be large, and other components of the battery adjacent to the multiple battery cells will need to withstand a greater expansion force, and may even break or break under the huge expansion force, thereby reducing the reliability and safety of the battery. Summary of the invention

[0004] In view of the above problems, the embodiments of the present application provide a battery and an electrical device, which can reduce the overall external expansion force of a plurality of battery cells and improve the safety and reliability of the battery.

[0005] According to one aspect of an embodiment of the present application, a battery is provided, comprising a plurality of battery cells arranged along a certain direction, the battery cells comprising an electrode assembly and a casing, the electrode assembly being placed in the casing, the plurality of battery cells comprising a first battery cell and a second battery cell, the first battery cell and the second battery cell being configured such that when the number of electrical cycles of the battery is greater than or equal to 100 times, the full charge group margin of the first battery cell is less than 1, and the full charge group margin of the second battery cell is greater than 1; the full charge group margin refers to the ratio of the maximum size of the electrode assembly to the minimum size of the casing along the arrangement direction of the plurality of battery cells when the battery cells are in a fully charged state.

[0006] By adopting the above scheme, when the number of battery cycles is greater than or equal to 100 times, by making the full charge group margin of the first battery cell less than 1, the gap between the shell side wall of the first battery cell and the electrode assembly is larger. When the expansion degree of the electrode assembly is within a certain range, the outer surface of the electrode assembly does not contact the inner wall of the shell, or although it contacts the side wall of the shell, the expansion force generated is small, so that the shell of the first battery cell does not expand and deform outward or the degree of expansion and deformation outward is small. When the shell side wall of the first battery cell is subjected to a large external force, it may even be concave and deformed inward. By making the full charge group margin of the second battery cell greater than 1, the gap between the shell side wall of the second battery cell and the electrode assembly is smaller, and when the electrode assembly undergoes a small expansion, it is easy to abut the shell side wall, and the shell side wall and the electrode assembly continue to expand outward together. In a battery including a first battery cell and a second battery cell, when the outer shell of the second battery cell contacts the outer shell of the first battery cell during expansion along the arrangement direction of the battery cells, the outer shell of the first battery cell will be squeezed, and the squeezed position of the outer shell of the first battery cell will be concave and deformed inward, thereby reducing the expansion force between two adjacent battery cells and making the size of the whole composed of the arranged multiple battery cells smaller when expanding outward along the arrangement direction, thereby resulting in a smaller external expansion force of the whole composed of the multiple battery cells, preventing the battery cells from causing squeezing damage to other components of the battery, thereby improving the electrical connection stability and safety of the battery.

[0007] In some embodiments, the first battery cell is further configured such that when the number of electrical cycles of the battery is greater than or equal to 100 times, a full charge group margin of the first battery cell is greater than or equal to 0.8.

[0008] By adopting the above scheme, along the arrangement direction of multiple battery cells, the gap between the electrode assembly of the first battery cell and the outer shell of the first battery cell is smaller to avoid the energy density of the first battery cell being too low, and when expansion occurs, the outer shell of the first battery cell can be recessed inwardly by a small amount to accommodate the expanded and protruding part of the second battery cell. At the same time, the outer shell of the first battery cell will not be recessed inwardly too much to cause itself to be damaged by excessive force, thereby improving the safety of the first battery cell.

[0009] In some embodiments, the second battery cell is further configured so that when the number of electrical cycles of the battery is greater than or equal to 100 times, the full charge group margin of the second battery cell is less than or equal to 1.2.

[0010] When the full charge group margin of the second battery cell is too large, the shell of the second battery cell is likely to bulge outward too much in the fully charged state and cause rupture, and the electrode assembly of the second battery cell will also cause the electrical cycle performance to deteriorate due to excessive expansion force. Therefore, by adopting the above solution, limiting the full charge group margin of the second battery cell to less than or equal to 1.2, it is possible to prevent the occurrence of the above adverse situations, or reduce the probability of the above adverse situations, and improve the service life and safety of the second battery cell.

[0011] In some embodiments, the battery has a matching group margin F, F=F3 / A, and F≤1.1; wherein F3 is the sum of the full charge group margins of all battery cells in the battery when the number of electrical cycles of the battery is greater than or equal to 100 times, and A is the total number of battery cells in the battery.

[0012] By adopting the above scheme, the matching group margin is used to measure the overall external expansion force of the multiple battery cells. When the matching group margin is too large, it means that the amount of expansion and protrusion of all the second battery cells is much greater than the maximum amount of depression that can be produced by squeezing all the first battery cells, resulting in excessive expansion and expansion force of the multiple battery cells as a whole. Therefore, limiting the matching group margin F≤1.1 can prevent the excessive expansion and expansion force of the multiple battery cells from causing squeezing damage to other components of the battery, thereby improving the stability of the internal electrical connection of the battery and the safety of the battery.

[0013] In some embodiments, the collocation group margin is greater than or equal to 0.9.

[0014] When the matching group margin is too small, it is easy to cause the total amount of expansion and protrusion of the second battery cell to be much smaller than the maximum total amount of depression that can be caused by squeezing the first battery cell. Therefore, by adopting the above scheme, the matching group margin is limited to be greater than or equal to 0.9, so that after the outer shell of the first battery cell is squeezed and depressed, it can contact the electrode assembly of the first battery cell, or the distance between the electrode assembly of the first battery cell is small, thereby preventing the waste of space in the first battery cell and causing a reduction in battery energy density.

[0015] In some embodiments, the collocation group margin is less than or equal to 1.05.

[0016] By adopting the above solution, the overall expansion amount and expansion force of the multiple battery cells are further limited within a safe range, thereby improving the electrical connection stability inside the battery and the safety of the battery.

[0017] In some embodiments, the first battery cell is disposed adjacent to the second battery cell.

[0018] By adopting the above scheme, the expansion amount generated by each second battery cell can be partially accommodated by the first battery cell adjacent to it by recessing inward, so that the expansion force of the second battery cell can be more easily released outside the shell, thereby reducing the expansion force between adjacent battery cells and reducing the overall expansion amount and expansion force of multiple battery cells.

[0019] In some embodiments, the number of the first battery cells and the number of the second battery cells are equal.

[0020] By adopting the above solution, the value of the collocation group margin is converted into the quantity value of the first battery cell and the second battery cell, which facilitates the control of the value of the collocation group margin during the manufacturing process.

[0021] In some embodiments, the battery further includes two end plates, which are respectively located at one end of the plurality of battery cells along the arrangement direction and are disposed adjacent to the second battery cell.

[0022] When the battery is assembled, there is usually an assembly gap between the end plate and multiple battery cells. By adopting the above solution, after the second battery cell expands, the installation gap can be used to accommodate a part of the expansion to reduce the overall outward expansion size, or reduce the degree of deformation of the end plate.

[0023] According to another aspect of an embodiment of the present application, there is provided an electrical device, comprising the battery in any one of the above embodiments, wherein the battery is used to provide electrical energy.

[0024] By adopting the above scheme, the expansion force between multiple battery cells of the battery is small, and the expansion force of the multiple battery cells as a whole on other components of the battery is also small, thereby improving the electrical connection stability and use safety of the battery and slowing down the deterioration rate of the battery's electrical cycle performance.

[0025] The embodiment of the present application provides a battery comprising a first battery cell and a second battery cell. The first battery cell and the second battery cell are configured such that when the number of electrical cycles of the battery is greater than or equal to 100 times, the full charge group margin of the first battery cell is less than 1, and the full charge group margin of the second battery cell is greater than 1. When the battery provided by the embodiment of the present application is in use, when the outer shell of the second battery cell contacts the outer shell of the first battery cell during expansion along the arrangement direction, it will squeeze the outer shell of the first battery cell, and cause the squeezed position of the outer shell of the first battery cell to be concave and deformed inward, thereby reducing the expansion force between two adjacent battery cells, and making the overall outward expansion size of the multiple battery cells arranged along the arrangement direction smaller, thereby resulting in a smaller outward expansion force of the overall body composed of the multiple battery cells, preventing the battery cells from causing squeezing damage to other components of the battery, thereby improving the electrical connection stability and safety of the battery.

[0026] The above description is only an overview of the technical solution of the embodiment of the present application. In order to more clearly understand the technical means of the embodiment 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 embodiment 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

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 It is a schematic diagram of the structure of an electrical device in one embodiment of the present application.

[0029] Figure 2 Schematic diagram of the structure of a battery in one embodiment of the present application.

[0030] Figure 3 Schematic diagram of the explosion structure of a battery cell in one embodiment of the present application.

[0031] Figure 4 It is a schematic diagram of the structure of the first battery cell when it is fully charged and not squeezed.

[0032] Figure 5 It is a schematic diagram of the structure of the second battery cell when it is in a fully charged state.

[0033] Figure 6 Schematic diagram of the structure of a first battery cell and a second battery cell when the battery is in a fully charged state in one embodiment of the present application.

[0034] Figure 7 Schematic diagram of the arrangement of five battery cells in Experiment 1.

[0035] Figure 8 Schematic diagram of the arrangement of five battery cells in Experiment 2.

[0036] Fig. 9 Schematic diagram of the arrangement of five battery cells in Experiment 3.

[0037] Fig.10 Schematic diagram of the arrangement of five battery cells in Experiment 4.

[0038] Fig.11 Schematic diagram of the arrangement of five battery cells in Experiment 5.

[0039] Fig.12 Schematic diagram of the arrangement of five battery cells in Experiment 6.

[0040] Fig.13 It is a schematic structural diagram of a first battery cell and a second battery cell when the battery in another embodiment of the present application is in a fully charged state.

[0041] Fig.14 Schematic diagram of the structure of a battery with end plates in a fully charged state in one embodiment of the present application.

[0042] Explanation of the reference numerals: 2, automobile; 200, battery; 210, controller; 220, motor; 300, battery module; 201, first housing; 202, second housing; 400, battery cell; 410, electrode assembly; 420, outer shell; 421, casing; 422, end cover; 4221, electrode terminal; 401, first battery cell; 402, second battery cell; 500, end plate. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] 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 in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0045] The terms "comprising" and "having" and any variations thereof in the specification, claims and drawings of this application are intended to cover but not exclude other contents. The word "a" or "an" does not exclude the presence of a plurality.

[0046] 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 "embodiments" 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.

[0047] The term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: 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.

[0048] The directional words appearing in the following description are all directions shown in the figures, and do not limit the specific structure of the battery or electrical device of the present application. For example, in the description of the present application, the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present application.

[0049] In addition, the expressions of the indicated directions, such as the X direction, the Y direction, and the Z direction, used to illustrate the operation and construction of the components of the battery or electrical device of this embodiment are not absolute but relative, and although these indications are appropriate when the components of the battery pack are in the positions shown in the figures, when these positions change, these directions should be interpreted differently to correspond to the changes.

[0050] In addition, the terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0051] In the description of the present application, unless otherwise specified, "plurality" means more than two (including two), and similarly, "multiple groups" means more than two groups (including two).

[0052] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, the "connection" or "connection" of a mechanical structure may refer to a physical connection. For example, the physical connection may be a fixed connection, such as a fixed connection through a fixing member, such as a fixed connection through a screw, bolt or other fixing member; the physical connection may also be a detachable connection, such as a mutual snap connection or snap connection; the physical connection may also be an integral connection, such as welding, bonding or integral molding to form a connection for connection. The "connection" or "connection" of a circuit structure may refer to an electrical connection or a signal connection in addition to a physical connection. For example, it may be a direct connection, that is, a physical connection, or it may be an indirect connection through at least one intermediate element, as long as the circuit is connected, or it may be the internal connection of two elements; the signal connection may refer to a signal connection through a media medium, such as a radio wave, in addition to a signal connection through a circuit. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0053] In the present 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., and the embodiments of the present application do not limit this. Battery cells may be cylindrical, flat, rectangular or other shapes, etc., and the embodiments of the present application do not limit this. Battery cells are generally divided into three types according to the packaging method: cylindrical battery cells, square battery cells and soft-pack battery cells, and the embodiments of the present application do not limit this.

[0054] The battery cell includes a housing, an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet and a separator. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. The positive electrode sheet includes a positive electrode collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode collector. The current collector not coated with the positive electrode active material layer protrudes from the current collector coated with the positive electrode active material layer. The current collector not coated with the positive electrode active material layer serves as the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide, etc. The negative electrode sheet includes a negative electrode collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode collector. The current collector not coated with the negative electrode active material layer protrudes from the current collector coated with the negative electrode active material layer. The current collector not coated with the negative electrode active material layer serves as the negative electrode tab. The material of the negative electrode collector can be copper, and the negative electrode active material can be carbon or silicon, etc. In order to ensure that a large current can be passed without melting, the number of positive electrode tabs is multiple and stacked together, and the number of negative electrode tabs is multiple and stacked together. The material of the separator can be polypropylene (PP) or polyethylene (PE). In addition, the electrode assembly can be a winding structure or a laminated structure, and the embodiments of the present application are not limited thereto.

[0055] During the charge and discharge cycle, the electrode assembly in the battery cell will expand due to the change in the lattice spacing of the negative electrode active material during the lithium ion embedding process. When the expanded size of the electrode assembly exceeds the original size of the battery cell shell, the battery cell will appear to be in a swollen state.

[0056] In batteries, multiple battery cells are usually arranged side by side into groups for the convenience of connecting them in series and parallel. During the charge and discharge cycle of the battery, especially when the battery is in a fully charged state, the electrode assemblies in each battery cell almost all expand to a large extent. When the full charge group margin of the battery cell is set to a large value, the expansion force of each battery cell to the outside of the shell is large, which easily causes a large interaction force between the arranged battery cells, resulting in a rapid deterioration of the battery cell cycle performance, thereby causing a rapid decrease in the battery life. In addition, when multiple battery cells arranged in groups expand, the accumulation of the expanded size will cause a large change in the overall size, which is easy to squeeze other components of the battery, such as electrical connection components, cooling components, etc., thereby affecting the normal functioning of other components, resulting in reduced reliability and safety of the battery, and forming a safety hazard.

[0057] Based on the above problems, the applicant found that using battery cells with smaller full charge group margin to compose a battery can alleviate the battery performance degradation caused by the expansion of battery cell size. However, setting the full charge group margin to a smaller value will affect the battery capacity, causing the battery energy density to decrease.

[0058] In view of this, an embodiment of the present application provides a battery, which arranges battery cells with different full charge group margins into groups in the battery, thereby reducing the impact of battery cell expansion on battery reliability, safety and service life, while reducing the loss of battery capacitance, so that the battery can have a higher energy density.

[0059] The battery in the embodiments of the present application can be applicable to various devices using batteries, such as mobile phones, portable devices, laptop computers, electric vehicles, electric toys, electric tools, electric vehicles, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft, etc., but are not limited to these.

[0060] like Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of an electric device provided in one embodiment of the present application, and the electric device is described by taking a car 2 as an example. The car 2 can be a fuel car, a gas car or a new energy car. The new energy car can be a pure electric car, a hybrid car or an extended-range car, etc. The car 2 includes a battery 200, a controller 210 and a motor 220. The battery 200 is used to supply power to the controller 210 and the motor 220 as the operating power supply and driving power supply of the car 2. For example, the battery 200 is used to supply power to the controller 210 and the motor 220 during the start-up, navigation and operation of the car 2. For example, the battery 200 supplies power to the controller 210, the controller 210 controls the battery 200 to supply power to the motor 220, and the motor 220 receives and uses the power of the battery 200 as the driving power supply of the car 2, replacing or partially replacing the fuel or natural gas to provide driving power for the car 2.

[0061] like Figure 2 As shown, in order to make the battery 200 achieve a higher function to meet the use requirements, the battery 200 may include a plurality of battery modules 300 and a box body electrically connected to each other, wherein the box body includes a first box body 201 and a second box body 202, wherein the first box body 201 and the second box body 202 are buckled with each other, and the plurality of battery modules 300 are arranged in a space enclosed by the first box body 201 and the second box body 202. The first box body 201 and the second box body 202 may be made of aluminum, aluminum alloy or other metal materials. In some embodiments, the first box body 201 and the second box body 202 are sealed and connected.

[0062] like Figure 2As shown, the battery module 300 may include one or more battery cells 400. When the battery module 300 includes multiple battery cells 400, the multiple battery cells 400 may be electrically connected in series, in parallel, or in a hybrid manner to achieve a larger current or voltage, wherein the hybrid means a combination of series and parallel. In addition, the multiple battery cells 400 may be arranged according to a predetermined rule, such as Figure 2 As shown, the battery cell 400 can be placed upright, with the height direction of the battery cell 400 consistent with the Z direction, and multiple battery cells 400 are arranged side by side along the Y direction; or, the battery cell 400 can be placed flat, with the width direction of the battery cell 400 consistent with the Z direction, and multiple battery cells 400 can be stacked in at least one layer along the Z direction, and each layer includes multiple battery cells 400 arranged along the X direction or the Y direction.

[0063] Figure 3 An exploded diagram of a battery cell provided in an embodiment of the present application, Figure 4 is a schematic diagram of the structure of the first battery cell in a fully charged state, Figure 5 is a schematic diagram of the structure of the second battery cell in a fully charged state, Figure 6 This is a schematic diagram of the structure of multiple battery cells in a battery in an embodiment of the present application in a fully charged state. Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, the battery 200 provided in the embodiment of the present application includes a plurality of battery cells 400 arranged along a certain direction (shown as the Y direction in the figure), such as Figure 3 , Figure 4 and Figure 5 As shown, the battery cell 400 includes an electrode assembly 410 and a housing 420, and the electrode assembly 410 is placed in the housing 420; Figure 6 As shown, multiple battery cells 400 include a first battery cell 401 and a second battery cell 402. The first battery cell 401 and the second battery cell 402 are configured so that when the number of electrical cycles of the battery is greater than or equal to 100 times, the full charge group margin of the first battery cell 401 is less than 1, and the full charge group margin of the second battery cell 402 is greater than 1; the full charge group margin refers to the ratio of the maximum size of the electrode assembly 410 to the minimum size of the outer casing 420 along the arrangement direction Y of the multiple battery cells 400 when the battery cells 400 are in a fully charged state.

[0064] like Figure 3As shown, the housing 420 includes a shell 421 and an end cap 422. The shell 421 has a receiving cavity, and one side of the receiving cavity has an opening. One or more electrode assemblies 410 are placed in the receiving cavity through the opening. The end cap 422 cooperates with the opening of the shell 421 to seal the electrode assembly 410 in the shell 421. The end cap 422 is provided with an electrode terminal 4221, and the electrode terminal 4221 is used to be electrically connected to the electrode assembly 410. The battery cell 400 is electrically connected to an external device through the electrode terminal 4221. The shape and size of the shell 421 are determined according to the shape and number of the electrode assembly 410.

[0065] In some embodiments, the shell 421 and the end cover 422 are both made of metal, such as aluminum or aluminum alloy, and the shell 421 and the end cover 422 are connected by welding.

[0066] In the embodiment of the present application, the height direction, width direction and thickness direction of the battery cell 400 are perpendicular to each other. The height direction of the battery cell 400 may refer to the direction in which the electrode terminal 4221 of the battery cell 400 is led out, and the dimension of the width direction of the battery cell 400 is less than or equal to the dimension of the length direction of the battery cell 400. During use, the battery cell 400 will expand in both the width direction and the length direction, and generally the expansion amount in the width direction is greater than the expansion amount in the length direction.

[0067] A certain direction may refer to the length direction of the battery cell 400, that is, Figure 3 The X direction in the figure may also be the width direction of the battery cell 400, that is, Figure 3 Considering that the expansion amount of the battery cell 400 in the width direction is generally greater than the expansion amount of the battery cell 400 in the length direction in the fully charged state, the above-mentioned certain direction is defined as the width direction of the battery cell 400 in the embodiment of the present application. Of course, in other embodiments of the present application, a certain direction may also be defined as the length direction of the battery cell 400.

[0068] One electrical cycle of the battery 200 refers to a process in which the battery 200 is charged to a fully charged state and then discharged to a fully discharged state. The fully charged state refers to a state in which the state of charge of the battery 200 is greater than 99%, and the fully discharged state refers to a state in which the state of charge of the battery 200 is less than 1%.

[0069] During the use of the battery cell 400, the electrode assembly 410 will shrink or expand as the charging and discharging process progresses. Normally, during the charging process, the electrode assembly 410 will expand, and during the discharging process, the electrode assembly 410 will shrink. The degree of expansion of the electrode assembly 410 is often related to the charge state of the battery cell 400. Normally, when the battery cell 400 is fully charged, the expansion of the electrode assembly 410 reaches its peak.

[0070] Since the size of the electrode assembly 410 is different from the size of the accommodating cavity of the shell 420, and the expansion degree of the electrode assembly 410 made of different materials is different during charging, when the battery cell 400 is in a fully charged state, it usually presents two states.

[0071] like Figure 4 As shown, the first state is due to the fact that the volume of the electrode assembly 410 is much smaller than the volume of the accommodating cavity of the shell 420 or the expansion amount of the electrode assembly 410 when fully charged is small, resulting in the expansion of the battery cell 400 only being the expansion of the electrode assembly 410 itself, and the shell 420 does not show any volume change. In this state, the space in the accommodating cavity of the shell 420 is sufficient to accommodate the volume of the electrode assembly 410 in the fully charged state, that is, in a certain direction, the outer surface of the electrode assembly 410 does not contact the inner wall of the shell 420, or although it contacts the side wall of the shell 420, the abutment force on the side wall of the shell 420 is small, which is not enough to cause the side wall of the shell 420 to expand and deform outward. At this time, along the arrangement direction of the multiple battery cells, the ratio of the maximum size of the electrode assembly 410 to the minimum size of the outer shell 420 is less than 1, that is, the full charge group margin of the battery cell 400 with the first full charge state is less than 1. The battery cell 400 with the first full charge state is defined as the first battery cell 401 in the embodiment of the present application. Since the interior of the outer shell of the first battery cell 401 is not supported by the electrode assembly, when the side wall of the outer shell of the first battery cell 401 is subjected to a large external force, it may be concave and deformed inward.

[0072] like Figure 5 As shown, the second state is due to the small difference between the volume of the electrode assembly 410 and the volume of the accommodating cavity of the shell 420 or the large expansion of the electrode assembly 410 when fully charged, which leads to the electrode assembly 410 being easily abutted against the side wall of the shell 420 when it expands slightly, and the side wall of the shell 420 and the electrode assembly 410 continue to expand and bulge outward together. At this time, along the arrangement direction of the multiple battery cells, the ratio of the maximum size of the electrode assembly 410 to the minimum size of the shell 420 is greater than 1, that is, the full charge group margin of the battery cell 400 with the second full charge state is greater than 1, and the battery cell 400 with the second full charge state is defined as the second battery cell 402 in the embodiment of the present application. When the shell side wall of the second battery cell 402 contacts the first battery cell 401 during the process of bulging outward, the shell side wall of the first battery cell 401 may be concave under the large expansion force.

[0073] In the embodiment of the present application, there is no limitation on the number of the first battery cells 401 and the number of the second battery cells 402. As long as any one of the battery cells 400 satisfies the condition that the full charge group margin is less than 1 when the number of battery electrical cycles is greater than or equal to 100 times, it can be considered that the first battery cell 401 exists in the battery. Similarly, as long as any one of the battery cells 400 satisfies the condition that the full charge group margin is greater than 1 when the number of battery electrical cycles is greater than or equal to 100 times, it can be considered that the second battery cell 402 exists in the battery.

[0074] It should be emphasized that since the expansion degree of different battery cells 400 in the fully charged state is different, and as the number of electrical cycles of the battery 200 increases, the difference between different battery cells 400 gradually increases. Therefore, the embodiment of the present application uses the full charge group margin value of the first battery cell 401 and the second battery cell 402 after the number of electrical cycles of the battery 200 is greater than or equal to 100 times as the condition for distinguishing the first battery cell 401 and the second battery cell 402, so that the distinction between the first battery cell 401 and the second battery cell 402 is more accurate.

[0075] like Figure 6 As shown, in a battery including a first battery cell 401 and a second battery cell 402, when the shell of the second battery cell 402 contacts the shell of the first battery cell 401 during expansion along the arrangement direction of the multiple battery cells, it will squeeze the shell of the first battery cell 401, and cause the squeezed position of the shell of the first battery cell 401 to be concave and deformed inward, thereby reducing the expansion force between two adjacent battery cells and making the overall outward expansion size of the multiple battery cells smaller, thereby resulting in a smaller outward expansion force of the overall multiple battery cells, preventing the battery cells from causing squeezing damage to other components of the battery, thereby improving the electrical connection stability and safety of the battery.

[0076] In some embodiments, the first battery cell 401 is further configured such that when the number of electrical cycles of the battery is greater than or equal to 100 times, the full charge group margin of the first battery cell 401 is greater than or equal to 0.8.

[0077] By adopting the above scheme, along the arrangement direction of the multiple battery cells, the gap between the electrode assembly of the first battery cell 401 and the shell of the first battery cell 401 is small, and the electrode assembly of the first battery cell 401 can be relatively firmly fixed in the shell of the first battery cell, and will not shake significantly during use, thereby ensuring the stability of the electrical connection of the first battery cell 401. On this basis, when the battery is in a fully charged state, the shell of the first battery cell 401 can also be slightly recessed inward to accommodate the expanded and protruding part of the second battery cell 402, and the shell of the first battery cell 401 will not be recessed too much inward to cause itself to be damaged due to excessive force. Therefore, the above scheme enables the first battery cell 401 to achieve the effect of reducing the overall expansion amount and expansion force of the multiple battery cells on the basis of ensuring its own electrical connection stability and safety.

[0078] In some embodiments, the second battery cell 402 is further configured such that when the number of electrical cycles of the battery is greater than or equal to 100 times, the full charge group margin of the second battery cell 402 is less than or equal to 1.2.

[0079] When the full charge group margin of the second battery cell 402 is too large, the shell of the second battery cell 402 may easily bulge outward too much in the fully charged state, causing the welding position between the shell and the end cover to tear, and the electrode assembly of the second battery cell 402 may also cause the electrical cycle performance to deteriorate due to excessive expansion force.

[0080] Therefore, by limiting the full charge group margin of the second battery cell 402 to be less than or equal to 1.2, the above adverse situations can be prevented from occurring, or the probability of the above adverse situations occurring can be reduced, thereby improving the service life and safety of the second battery cell 402.

[0081] In some embodiments, the battery has a matching group margin F, F=F3 / A, and F≤1.1; wherein F3 is the sum of the full charge group margins of all battery cells in the battery when the number of electrical cycles of the battery is greater than or equal to 100 times, and A is the total number of battery cells in the battery.

[0082] For example, the battery includes two first battery cells 401 and three second battery cells 402. The full charge group margins of the two first battery cells 401 when the battery has been electrically cycled greater than or equal to 100 times and is in a fully charged state are 0.8 and 0.9 respectively. The full charge group margins of the three second battery cells 402 when the battery has been electrically cycled greater than or equal to 100 times and is in a fully charged state are 1.1, 1.2 and 1.3 respectively. Then, F3=0.8+0.9+1.1+1.2+1.3=5.3, A=5, and the battery matching group margin F=5.3 / 5=1.06.

[0083] The matching group margin is used to measure the overall external expansion force of multiple battery cells. When the matching group margin is too large, it means that the amount of expansion and protrusion of all second battery cells 402 is much larger than the maximum amount of depression that can be produced after all first battery cells 401 are squeezed. This results in the expansion and protrusion of the second battery cells 402 being unable to be completely offset by the depression of the first battery cells 401, resulting in excessive overall expansion and expansion force of the multiple battery cells.

[0084] By limiting the matching group margin F≤1.1, it is possible to prevent the overall expansion amount and expansion force of multiple battery cells from being too large, thereby preventing other battery components from being squeezed and damaged, thereby improving the electrical connection stability inside the battery and the safety of the battery.

[0085] In some embodiments, the collocation group margin is greater than or equal to 0.9.

[0086] When the matching group margin is too small, it means that the amount of expansion and protrusion of all the second battery cells 402 is much smaller than the maximum amount of depression that can be caused by squeezing all the first battery cells 401. For example, in one possible situation, all the second battery cells 402 contained in the battery have expanded to their maximum volume when fully charged, but there is still a situation where the electrode assembly of the first battery cell 401 is not in contact with the inner wall of the outer shell at the point where the depression is the largest. This results in a large idle space in the shell of the first battery cell 401, resulting in a waste of space in the battery. The existence of this space also leads to a reduction in the energy density of the first battery cell 401.

[0087] Therefore, by limiting the matching group margin to be greater than or equal to 0.9, the outer shell of the first battery cell 401 can contact the electrode assembly of the first battery cell 401 after being squeezed and dented, or the distance between the outer shell and the electrode assembly of the first battery cell 401 is smaller, thereby preventing the waste of space in the first battery cell 401 and the reduction of battery energy density.

[0088] In some embodiments, the collocation group margin is less than or equal to 1.05.

[0089] By adopting the above solution, the overall expansion amount and expansion force of the multiple battery cells are further limited within a safe range, thereby improving the electrical connection stability inside the battery and the safety of the battery.

[0090] In order to verify the influence of the number and arrangement order of the first battery cell 401 and the second battery cell 402 on the overall volume energy density and expansion force of the plurality of battery cells, the following experiment was conducted in the embodiment of the present application:

[0091] Experiment 1: Select five second battery cells 402, each of which has a full charge group margin of 1.11 and is a ternary battery cell. Arrange the five second battery cells 402 along their width direction. Connect the five second battery cells 402 in series, and after 1000 electrical cycles, measure the volume energy density and expansion force of the whole composed of the five battery cells. The arrangement state of multiple battery cells in Experiment 1 is as follows: Figure 7 shown.

[0092] Experiment 2: Select a first battery cell 401 and four second battery cells 402. The full charge group margin of the first battery cell 401 is 0.9, and the full charge group margin of the four second battery cells 402 is 1.11. The first battery cell 401 and the second battery cell 402 are both ternary battery cells. Arrange the first battery cell 401 and the four second battery cells 402 along their width direction, and have two second battery cells 402 on each side of the first battery cell 401. Connect the five battery cells in series, and after 1000 electrical cycles, measure the overall volume energy density and expansion force of the five battery cells. The arrangement of multiple battery cells in Experiment 2 is as follows: Figure 8 shown.

[0093] Experiment 3: Select two first battery cells 401 and three second battery cells 402. The full charge group margin of the two first battery cells 401 is 0.9, and the full charge group margin of the three second battery cells 402 is 1.11. The first battery cells 401 and the second battery cells 402 are both ternary battery cells. Arrange the two first battery cells 401 and the three second battery cells 402 along their width direction, and make the first battery cells 401 and the second battery cells 402 adjacent to each other. Connect the five battery cells in series, and after 1000 electrical cycles, measure the overall volume energy density and expansion force of the five battery cells. The arrangement state of multiple battery cells in Experiment 3 is as follows: Fig. 9 shown.

[0094] Experiment 4: Select three first battery cells 401 and two second battery cells 402. The full charge group margins of the three first battery cells 401 are all 0.9, and the full charge group margins of the two second battery cells 402 are all 1.11. The first battery cells 401 and the second battery cells 402 are both ternary battery cells. Arrange the three first battery cells 401 and the two second battery cells 402 along their width direction, and make the first battery cells 401 and the second battery cells 402 adjacent to each other. Connect the five battery cells in series, and after 1000 electrical cycles, measure the volume energy density and expansion force of the whole composed of the five battery cells. The arrangement state of multiple battery cells in Experiment 4 is as follows: Fig.10 shown.

[0095] Experiment 5: Select three first battery cells 401 and two second battery cells 402. The full charge group margin of the three first battery cells 401 is 0.9, and the full charge group margin of the two second battery cells 402 is 1.11. The first battery cells 401 and the second battery cells 402 are both ternary battery cells. Arrange the three first battery cells 401 and the two second battery cells 402 along their width direction, and arrange the three first battery cells 401 and the two second battery cells 402 in a continuous arrangement. Connect the five battery cells in series, and after 1000 electrical cycles, measure the overall volume energy density and expansion force of the five battery cells. The arrangement state of multiple battery cells in Experiment 5 is as follows: Fig.11 shown.

[0096] Experiment 6: Select five first battery cells 401, each of which has a full charge group margin of 0.9 and is a ternary battery cell. Arrange the five first battery cells 401 along their width direction. Connect the five first battery cells 401 in series, and after 1000 electrical cycles, measure the volume energy density and expansion force of the whole composed of the five battery cells. The arrangement of multiple battery cells in Experiment 6 is as follows: Fig.12 shown.

[0097] The experimental data of the above 6 groups of experiments are recorded in the table below.

[0098]

[0099] It can be seen from the above experimental data that the greater the proportion of the first battery cells 401 in the total battery cells, the smaller the overall volume energy density of the multiple battery cells, and the smaller the expansion force; it can be seen from the data of Experiments 4 and 5 that when the proportion of the first battery cells 401 in the total battery cells is equal, the total expansion force of the multiple battery cells when the first battery cells 401 and the second battery cells 402 are adjacent to each other is less than the total expansion force of the multiple battery cells when all the first battery cells 401 are continuously arranged and all the second battery cells 402 are continuously arranged.

[0100] It can be understood that when the full charge group margin of each first battery cell 401 is equal, and the full charge group margin of each second battery cell 402 is equal, the greater the proportion of the first battery cells 401 in the total battery cells, the smaller the battery collocation group margin is. It can be concluded that the smaller the battery collocation group margin is, the smaller the battery energy density is, and the smaller the battery expansion force is. When the battery collocation group margin remains unchanged, the battery volume energy density remains unchanged, but even if the battery volume energy density remains unchanged, the battery expansion force will change due to different battery arrangement states.

[0101] Therefore, in order to reduce the expansion force of the battery while keeping the volume energy density of the battery unchanged, Fig.13 As shown, in some embodiments, the first battery cell 401 is disposed adjacent to the second battery cell 402 .

[0102] By adopting the above solution, the expansion amount generated by each second battery cell 402 can be offset by the inward depression of the adjacent first battery cell 401, so that the expansion force of the second battery cell 402 is released faster, thereby reducing the expansion force between adjacent battery cells and reducing the overall expansion amount and expansion force of multiple battery cells.

[0103] like Fig.13 As shown, in some embodiments, the number of the first battery cells 401 and the number of the second battery cells 402 are equal.

[0104] By adopting the above scheme, the value of the collocation group margin is converted into the quantity value of the first battery cell 401 and the second battery cell 402, so as to facilitate the control of the value of the collocation group margin during the manufacturing process. For example, in the manufacturing process of the battery, the full charge group margin of the first battery cell 401 of the same type and parameter is equal or slightly different when the number of electric cycles is greater than or equal to 100 times, which is about 0.8, and the full charge group margin of the second battery cell 402 of the same type and parameter is equal or slightly different when the number of electric cycles is greater than or equal to 100 times, which is about 1.2. At this time, it is only necessary to assemble the same number of first battery cells 401 and second battery cells 402 to form a battery, so that the value of the collocation group margin of the battery can be within the expected range close to 1, without the need for personnel to calculate and match the number of the first battery cell 401 and the second battery cell 402 during the battery assembly process to obtain a collocation group margin that meets the requirements. Therefore, the above scheme greatly simplifies the assembly process of the battery, making the collocation group margin of the battery more controllable.

[0105] like Fig.14 As shown, in some embodiments, the battery further includes two end plates 500 , which are respectively located at one end of the plurality of battery cells along the arrangement direction and are disposed adjacent to the second battery cell 402 .

[0106] The material of the end plate 500 can be a metal material, such as aluminum, aluminum alloy, etc. The metal end plate 500 can resist the expansion force of multiple battery cells 400 during the charging and discharging process. The material of the end plate 500 can also be a non-metallic material, such as polycarbonate-ABS resin composite material (PC-ABS), polypropylene (PP), fusible polytetrafluoroethylene (FPA), etc. The non-metallic end plate 500 can prevent the end plate 500 itself from short-circuiting with the battery cell 400. The end plate 500 can also be a composite of a metal material and a non-metallic material, for example, a layer of non-metallic material is composited on the outer layer of the metal material.

[0107] The two end plates 500 are used to resist the expansion force of the multiple battery cells 400 during the charging and discharging process, and the multiple battery cells 400 are restricted within a certain range, so that the structure of the battery 200 is more stable.

[0108] The end plate 500 is a component used to resist the dimensional expansion of the multiple battery cells 400 along the arrangement direction during the charge and discharge cycle. The end plate 500 and the side plate are used together to limit the multiple battery cells 400, so as to make the overall structure of the battery 200 more stable. During the assembly process of the battery 200, there is an installation gap between the end plate 500 and the multiple battery cells 400. This gap can be used to accommodate the expansion and deformation of a part of the battery cells 400. The end plate 500 and the second battery cell 402 are set adjacent to each other. After the second battery cell 402 expands, the gap becomes smaller or disappears, so as to reduce the outward deformation of the end plate 500, thereby reducing the degree of outward deformation and expansion of the overall size after the multiple battery cells 400 are grouped.

[0109] According to another aspect of an embodiment of the present application, there is provided an electrical device, comprising the battery in any one of the above embodiments, wherein the battery is used to provide electrical energy.

[0110] By adopting the above scheme, the expansion force between the multiple battery cells that make up the battery is small, and the expansion force of the multiple battery cells as a whole on other components of the battery is also small, thereby improving the electrical connection stability and use safety of the battery and slowing down the rate of deterioration of the battery's electrical cycle performance.

[0111] In summary, the embodiment of the present application provides a battery including a first battery cell and a second battery cell. The first battery cell and the second battery cell are configured so that when the number of electrical cycles of the battery is greater than or equal to 100 times, the full charge group margin of the first battery cell is less than 1, and the full charge group margin of the second battery cell is greater than 1, so that when the battery provided by the embodiment of the present application is in use, when the outer shell of the second battery cell contacts the outer shell of the first battery cell during expansion along the arrangement direction, it will squeeze the outer shell of the first battery cell, and cause the squeezed position of the outer shell of the first battery cell to be concave and deformed inward, thereby reducing the expansion force between two adjacent battery cells, and making the overall outward expansion size of the multiple battery cells arranged in a certain direction smaller, thereby resulting in the overall outward expansion force of the multiple battery cells being smaller, preventing the battery cells from causing squeezing damage to other components of the battery, thereby improving the electrical connection stability and safety of the battery. On this basis, the battery can also ensure a higher energy density.

[0112] Those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0113] As described above, 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 make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery, characterized in that: include: A plurality of battery cells arranged along a certain direction, the battery cells comprising an electrode assembly and a shell, the electrode assembly being placed in the shell, the plurality of battery cells comprising a first battery cell and a second battery cell, the first battery cell and the second battery cell being configured such that when the number of electrical cycles of the battery is greater than or equal to 100 times, the full charge group margin of the first battery cell is greater than or equal to 0.8, and the full charge group margin of the first battery cell is less than 1, the full charge group margin of the second battery cell is greater than 1, and the full charge group margin of the second battery cell is less than or equal to 1.2, the full charge group margin referring to the ratio of the maximum size of the electrode assembly to the minimum size of the shell along the arrangement direction of the plurality of battery cells when the battery cells are in a fully charged state.

2. The battery according to claim 1, characterized in that The battery has a matching group margin F, F=F3 / A, and F≤1.1; wherein F3 is the sum of the full charge group margins of all battery cells in the battery when the number of electrical cycles of the battery is greater than or equal to 100 times, and A is the total number of battery cells in the battery.

3. The battery according to claim 2, characterized in that The collocation group margin is greater than or equal to 0.

9.

4. The battery according to claim 2, characterized in that The collocation group margin is less than or equal to 1.

05.

5. The battery according to claim 1, characterized in that The first battery cell is disposed adjacent to the second battery cell.

6. The battery according to claim 2, characterized in that The number of the first battery cells is equal to the number of the second battery cells.

7. The battery according to claim 1, characterized in that The battery further includes two end plates, which are respectively located at one end of the plurality of battery cells along an arrangement direction and are disposed adjacent to the second battery cell.

8. An electrical device, characterized in that: A battery comprising any one of claims 1 to 7, wherein the battery is used to provide electrical energy.

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