Battery cell, battery and electric device

Abstract

The present application relates to the technical field of batteries, and discloses a battery cell, a battery and an electric device. The battery cell comprises an electrode assembly and a heat shrink film. The electrode assembly comprises a main body and tabs. The main body has two end surfaces arranged opposite to each other in a first direction and a circumferential surface connecting the two end surfaces, and the tabs are arranged on one of the end surfaces. The heat shrink film covers the circumferential surface in a circumferential direction of the main body, the heat shrink film has a head end and a tail end in the circumferential direction, and the head end and the tail end are connected. By providing the heat shrink film, the manufacturing efficiency of the battery cell can be improved to a certain extent, so that the manufacturing efficiency of the battery is improved.

Description

Battery cells, batteries and electrical equipment CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Chinese patent application No. 202420012704.X, filed on January 2, 2024, entitled “Battery Cell, Battery and Electrical Equipment,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] 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

[0003] Energy conservation and emission reduction are key to the sustainable development of the automotive industry. Electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of the sustainable development of the automotive industry. For electric vehicles, battery technology is a key factor in their development.

[0004] How to improve battery manufacturing efficiency is an urgent problem to be solved in battery technology. Summary of the Invention

[0005] In view of the above problems, the present application provides a battery cell, a battery and an electrical device, which can improve the manufacturing efficiency of the battery.

[0006] In a first aspect, the present application provides a battery cell, comprising an electrode assembly and a heat shrink film. The electrode assembly comprises a main body and a tab. The main body comprises a first end face and a second end face disposed opposite each other along a first direction, and a circumferential surface connecting the first end face and the second end face. The tab is disposed on the first end face and / or the second end face. The heat shrink film is wrapped around the circumferential surface of the main body, the heat shrink film having a leading end and a trailing end in the circumferential direction, the leading end and the trailing end being connected.

[0007] In the technical solution of the embodiment of the present application, the heat shrinkable film is used to constrain and shape the electrode assembly by the principle of thermal shrinkage. On the one hand, the hot pressing and cold pressing processes of the battery cell are eliminated, the manufacturing efficiency of the battery cell is improved, and the manufacturing cost of the battery cell is reduced; on the other hand, the heat shrinkable film can also be used to insulate and isolate the electrode assembly from the outer shell of the battery cell.

[0008] In one or more embodiments of the first aspect, the head end and the tail end are bonded by glue.

[0009] In the above solution, the manufacturing cost of the battery cell can be reduced by bonding the head end and the tail end of the heat shrink film with colloid.

[0010] In one or more embodiments of the first aspect, in the first direction, the main body has a first edge and a second edge, a first gap is formed between the heat shrinkable film and the first edge, and a second gap is formed between the heat shrinkable film and the second edge.

[0011] In the above solution, due to the existence of the first gap and the second gap, the heat shrink film does not completely cover the circumference of the main body in the first direction. In this way, the heat shrink film can bind the electrode assembly while also enabling the battery cell to have a higher volume energy density.

[0012] In one or more embodiments of the first aspect, in the first direction, the first gap and the second gap have the same size.

[0013] In the above solution, by simultaneously providing the first gap and the second gap of the same size, the restraining force on the electrode assembly can be substantially consistent, which is beneficial for the electrode assembly to have higher structural stability.

[0014] In one or more embodiments of the first aspect, the electrode assembly is a laminated electrode assembly.

[0015] In the above solution, the internal stress of the laminated electrode assembly itself is relatively small, and the heat shrink film has a better restraining and shaping effect on the laminated electrode assembly.

[0016] In one or more embodiments of the first aspect, the peripheral surface includes a first side surface and a second side surface disposed opposite each other along a second direction, and a third side surface and a fourth side surface disposed opposite each other along a third direction. The third direction is parallel to the stacking direction of the electrode assembly. The area of ​​the third side surface is greater than that of the first side surface. The second direction, the first direction, and the third direction are perpendicular to each other. The leading end and the trailing end are connected to form a connecting portion, and the connecting portion is located on the first side surface.

[0017] In the above solution, arranging the connecting portion on the first side surface can make the third side surface with a larger area have a higher flatness, which is beneficial to improving the volume energy density of the battery cell.

[0018] In one or more embodiments of the first aspect, in the third direction, the size of the connecting portion is L1, the size of the heat shrinkable film is L2, and the following relationship is satisfied: 0.3≤L1 / L2≤0.7.

[0019] In the above scheme, when L1 / L2≥0.3, in the third direction, the ratio of the size of the connecting portion to the size of the heat shrink film is large, the connection strength at the head end and the tail end is high, and the electrode assembly is not easily deformed after the heat shrink film constrains the electrode assembly; when L1 / L2≤0.7, in the third direction, the ratio of the size of the connecting portion to the size of the heat shrink film is small, the heat shrink film occupies less space inside the battery cell, and the volume energy density of the battery cell is high; therefore, when 0.3≤L1 / L2≤0.7, the battery cell can have a higher energy density while having a higher connection strength at the head end and the tail end.

[0020] In one or more embodiments of the first aspect, a portion of the heat shrinkable film covering the first side surface is provided with a first hole.

[0021] In the above scheme, when injecting liquid into the battery cell, the electrolyte can flow into the interior of the electrode assembly through the first hole. The electrolyte inside the battery cell is filled faster, which is beneficial to improving the injection efficiency of the battery cell and also improving the wetting effect of the electrolyte on the electrode assembly.

[0022] In one or more embodiments of the first aspect, the diameter of the first hole is D1, and in the third direction, the size of the heat shrinkable film is L2, satisfying: 0.3≤D1 / L2≤0.7.

[0023] In the above scheme, when D1 / L2≥0.3, the ratio of the diameter of the first hole to the size of the heat shrink film in the third direction is large, and the injection efficiency of the battery cell is high; when D1 / L2≤0.7, the ratio of the diameter of the first hole to the size of the heat shrink film in the third direction is small, the heat shrink film has a higher tensile strength, and after the heat shrink film constrains the electrode assembly, the structural stability of the electrode assembly is higher; therefore, when 0.3≤D1 / L2≤0.7, the battery cell can have a higher injection efficiency while the electrode assembly has a higher structural stability.

[0024] In one or more embodiments of the first aspect, 3 mm ≤ D1 ≤ 7 mm, 5 mm ≤ L2 ≤ 15 mm.

[0025] In the above scheme, when D1 ≥ 3mm, the diameter of the first hole is larger, and the battery cell injection efficiency is higher. When D1 ≤ 7mm, the diameter of the first hole is smaller, the heat shrink film has higher tensile strength, and the electrode assembly has higher structural stability. Therefore, when 3mm ≤ D1 ≤ 7mm, the battery cell injection efficiency is higher while the electrode assembly has higher structural stability. When L2 ≥ 5mm, the heat shrink film is larger in the third direction, and the heat shrink film has a better restraining effect on the electrode assembly. When L2 ≤ 15mm, the heat shrink film is smaller in the third direction, and the battery cell energy density is higher. Therefore, when 5mm ≤ L2 ≤ 15mm, the electrode assembly has a better restraining effect while the battery cell energy density is higher.

[0026] In one or more embodiments of the first aspect, 4 mm ≤ D1 ≤ 6 mm, 8 mm ≤ L2 ≤ 12 mm.

[0027] In the above scheme, when D1 ≥ 4mm, the battery cell injection efficiency can be further improved; when D1 ≤ 6mm, the structural stability of the electrode assembly can be further improved. Therefore, when 4mm ≤ D1 ≤ 6mm, the battery cell injection efficiency can be further improved while also further improving the structural stability of the electrode assembly. When L2 ≥ 8mm, the heat shrink film's restraining effect on the electrode assembly can be further improved; when L2 ≤ 12mm, the battery cell energy density can be further improved. Therefore, when 8mm ≤ L2 ≤ 12mm, the heat shrink film's restraining effect on the electrode assembly can be further improved while also further improving the battery cell energy density.

[0028] In one or more embodiments of the first aspect, the first hole does not overlap with the connecting portion.

[0029] In the above solution, since the first hole and the connecting portion do not overlap, the connecting portion will not block the first hole, which is beneficial to further improve the liquid injection efficiency of the battery cell.

[0030] In one or more embodiments of the first aspect, a plurality of first holes are provided, and the plurality of first holes are arranged at intervals along the first direction.

[0031] In the above solution, by providing a plurality of first holes, the liquid injection efficiency of the battery cell can be further improved.

[0032] In one or more embodiments of the first aspect, a second hole is provided in the portion of the heat shrinkable film covering the second side surface.

[0033] In the above scheme, when injecting liquid into the battery cell, the electrolyte can flow into the interior of the electrode assembly through the second hole. The electrolyte inside the battery cell is filled faster, which is beneficial to improving the injection efficiency of the battery cell and also improving the wetting effect of the electrolyte on the electrode assembly.

[0034] In one or more embodiments of the first aspect, the diameter of the second hole is D2, and in the third direction, the size of the heat shrinkable film is L2, satisfying: 0.3≤D2 / L2<1.

[0035] In the above scheme, when D2 / L2≥0.3, the ratio of the diameter of the second hole to the size of the heat shrink film in the third direction is large, and the injection efficiency of the battery cell is high; when D2 / L2<1, the ratio of the diameter of the second hole to the size of the heat shrink film in the third direction is small, the heat shrink film has a higher tensile strength, and after the heat shrink film constrains the electrode assembly, the structural stability of the electrode assembly is higher; therefore, when 0.3≤D2 / L2<1, the battery cell can have a higher injection efficiency while the electrode assembly has a higher structural stability.

[0036] In one or more embodiments of the first aspect, 3 mm ≤ D2 < 10 mm, 5 mm ≤ L2 ≤ 15 mm.

[0037] In the above scheme, when D2 ≥ 3mm, the diameter of the second hole is larger, and the battery cell injection efficiency is higher; when D2 < 10mm, the diameter of the second hole is smaller, and the structural stability of the electrode assembly is higher. Therefore, when 3mm ≤ D2 < 10mm, the battery cell injection efficiency is higher while the electrode assembly has higher structural stability. When L2 ≥ 5mm, the heat shrink film is larger in the third direction, and the heat shrink film has a better restraining effect on the electrode assembly. When L2 ≤ 15mm, the heat shrink film is smaller in the third direction, and the energy density of the battery cell is higher. Therefore, when 5mm ≤ L2 ≤ 15mm, the electrode assembly has a better restraining effect while the battery cell has a higher energy density.

[0038] In one or more embodiments of the first aspect, 4 mm ≤ D2 ≤ 8 mm, 8 mm ≤ L2 ≤ 12 mm.

[0039] In the above scheme, when D2 ≥ 4mm, the battery cell injection efficiency can be further improved; when D2 ≤ 8mm, the structural stability of the electrode assembly can be further improved. Therefore, when 4mm ≤ D2 ≤ 8mm, the battery cell injection efficiency can be further improved while also further improving the structural stability of the electrode assembly. When L2 ≥ 8mm, the heat shrink film's restraining effect on the electrode assembly can be further improved; when L2 ≤ 12mm, the battery cell energy density can be further improved. Therefore, when 8mm ≤ L2 ≤ 12mm, the heat shrink film's restraining effect on the electrode assembly can be further improved while also further improving the battery cell energy density.

[0040] In one or more embodiments of the first aspect, a plurality of second holes are provided, and the plurality of second holes are arranged at intervals along the first direction.

[0041] In the above solution, by providing a plurality of second holes, the liquid injection efficiency of the battery cell can be further improved.

[0042] In one or more embodiments of the first aspect, the battery cell further includes a first adhesive tape and a second adhesive tape. The first adhesive tape and the second adhesive tape are both disposed around the body along a circumferential direction of the body. The heat shrink film has a first end and a second end in a first direction. The first adhesive tape is used to secure the first end to the body. The second adhesive tape is used to secure the second end to the body.

[0043] In the above solution, the first and second tapes respectively secure the first and second ends to the main body, reducing the risk of secondary shrinkage of the heat shrink film during the subsequent drying process, which could expose the electrode assembly. This helps improve the reliability of the battery cell.

[0044] In one or more embodiments of the first aspect, an outer edge of the first adhesive tape is flush with the first end surface, and an outer edge of the second adhesive tape is flush with the second end surface.

[0045] In the above solution, since the outer edge of the first tape will not exceed the first end face and the outer surface of the second tape will not exceed the second end face, the risk of the first tape blocking the first end face and the second tape blocking the second end face, resulting in reduced battery cell injection efficiency and poor electrode assembly wetting effect, can be reduced.

[0046] In one or more embodiments of the first aspect, the tabs include a positive tab and a negative tab, both of which are disposed on the first end surface.

[0047] In the above solution, the positive electrode tab and the negative electrode tab are located on the same side of the electrode assembly, which is beneficial to improving the energy density of the battery cell in one direction.

[0048] In a second aspect, the present application provides a battery comprising the battery cell according to one or more of the above embodiments.

[0049] In the above solution, manufacturing the battery cells of one or more of the above embodiments has high manufacturing efficiency and low cost, which means that manufacturing batteries including the above battery cells can also have high manufacturing efficiency and low cost.

[0050] In a third aspect, the present application provides an electrical device, which includes a battery cell in one or more of the above embodiments, and the battery cell is used to provide electrical energy; or, the electrical device includes a battery in one or more of the above embodiments, and the battery is used to provide electrical energy.

[0051] In the above solution, the manufacturing of the battery cells or batteries in one or more of the above embodiments has high manufacturing efficiency and low cost, which means that the manufacturing of electrical equipment including the above battery cells or batteries can also have high manufacturing efficiency and low cost.

[0052] 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, which can be implemented in accordance with the contents of the specification, and to make 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

[0053] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0054] FIG1 is a schematic structural diagram of a vehicle according to some embodiments of the present application;

[0055] FIG2 is an exploded view of a battery according to some embodiments of the present application;

[0056] FIG3 is a cross-sectional view of a battery cell according to some embodiments of the present application;

[0057] FIG4 is an axonometric view of a portion of a battery cell according to some embodiments of the present application, showing a heat shrink film in an unfolded state;

[0058] FIG5 is a schematic structural diagram of an electrode assembly according to some embodiments of the present application;

[0059] FIG6 is an axonometric view of a portion of a battery cell according to some embodiments of the present application;

[0060] FIG7 is a partial enlarged view of point B in FIG6;

[0061] FIG8 is a schematic structural diagram of a battery cell according to some embodiments of the present application, showing a first hole;

[0062] FIG9 is a schematic structural diagram of a battery cell according to some embodiments of the present application, showing a second hole;

[0063] FIG10 is an axonometric view of a portion of the structure of a battery cell according to some other embodiments of the present application.

[0064] The accompanying drawings in the specific implementation manner are as follows:

[0065] 1000-Vehicle; 200-Controller; 300-Motor; 100-Battery; 11-Casing; 111-First Part; 112-Second Part; 12-Battery Cell; 121-Casing; 1211-End Cap; 1212-Casing; 122-Electrode Assembly; 1221-Main Body; 12211a-First End Face; 12211b-Second End Face; 12212-Peripheral Surface; 12212a-First Side Face; 12212b-Second Side Face; 12212c-Third Side Face; 12212d-Fourth Side Face; 12213- First edge; 12214-second edge; 1222-ear; 1222a-positive ear; 1222b-negative ear; 123-heat shrink film; 1231-head end; 1232-tail end; 1233-connecting part; 1234-first hole; 1235-second hole; 1236-first end; 1237-second end; 124-transfer plate; 125-electrode terminal; 126a-first gap; 126b-second gap; 127-first tape; 128-second tape; X-first direction; Y-second direction; Z-third direction. DETAILED DESCRIPTION

[0066] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0067] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0068] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0069] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0070] 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).

[0071] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0072] In the description of the embodiments of the present application, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; internal connections between two components or interactions between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application based on specific circumstances.

[0073] In this application, battery cells may include, but are not limited to, lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries. The shape of a battery cell may include, but is not limited to, a cylinder, a flat body, a rectangular parallelepiped, or other shapes. Battery cells, depending on the packaging method, may include, but are not limited to, cylindrical battery cells, prismatic battery cells, soft-pack battery cells, and blade battery cells.

[0074] In some high-power applications such as electric vehicles, the application of batteries includes three levels: battery cells, battery modules and batteries. The battery module is formed by electrically connecting a certain number of battery cells together and placing them in a frame in order to protect the battery cells from external impact, heat, vibration, etc. The battery refers to the final state of the battery system installed in the electric vehicle. The battery mentioned in the embodiments of the present application refers to a single physical module that includes one or more battery cells to provide higher voltage and capacity. The battery generally includes a box for encapsulating one or more battery cells. The box can reduce the risk of liquid or other foreign matter affecting the charging or discharging of the battery cells.

[0075] The following will mainly focus on rectangular parallelepiped battery cells. It should be understood that the embodiments described below are also applicable to cylindrical battery cells, soft-pack battery cells, or blade battery cells in some aspects.

[0076] In a typical battery cell structure, the battery cell includes a housing, an electrode assembly, and an electrolyte. The housing component may include an end cap and a shell, wherein the end cap closes an opening of the shell to define a receiving space for receiving the electrode assembly.

[0077] The electrode assembly is housed in the housing. It includes a positive electrode sheet, a negative electrode sheet, and a separator. Battery cells primarily operate by the movement of metal ions between the positive and negative electrode sheets. The positive electrode sheet includes a positive current collector and a positive active material layer. The positive active material layer is coated on the surface of the positive electrode collector. The uncoated positive electrode collector protrudes from the coated positive electrode collector, serving as the positive electrode tab. For lithium-ion batteries, for example, the positive electrode collector can be made of aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide. The negative electrode sheet includes a negative current collector and a negative active material layer. The negative active material layer is coated on the surface of the negative electrode collector. The uncoated negative electrode collector protrudes from the coated negative electrode collector, serving as the negative electrode tab. The negative electrode collector can be made of copper, and the negative electrode active material can be carbon, silicon, or other materials. To ensure high current flow without melting, multiple positive tabs are stacked together, and multiple negative tabs are stacked together. Furthermore, electrode assemblies can be formed using methods including, but not limited to, winding or lamination. For example, the lamination process involves stacking positive and negative electrode sheets with a separator to form an electrode assembly.

[0078] When the electrode assembly is placed in the housing, the outer surface of the electrode assembly is typically covered with an insulating film to reduce the risk of scratches from the housing and to insulate the electrode assembly from the housing wall. The insulating film is generally soft and flexible. One insulating film can cover one or more electrode assemblies. For example, when multiple electrode assemblies are housed within the housing, one insulating film can cover multiple electrode assemblies.

[0079] The tabs generally lead out the electrical energy of the electrode assembly by being electrically connected to the conductive member. In some cases, the conductive member is a transition piece connecting the tabs and the electrode terminals. In other cases, the conductive member is the electrode terminal.

[0080] Electrode terminals generally include positive and negative terminals. For rectangular battery cells, electrode terminals are typically located in the end caps. In some other cases, electrode terminals may also be located in the housing. Multiple battery cells can be connected in series and / or in parallel via the electrode terminals for various applications.

[0081] The development of battery technology must take into account multiple design factors at the same time, such as reliability, cycle life, discharge capacity, charge and discharge rate, battery energy density and other performance parameters. In addition, battery manufacturing efficiency must also be considered.

[0082] After the electrode assembly is stacked or wound, it must undergo shaping and drying before being placed in a battery case. Typically, the electrode assembly undergoes at least one process: roll pressing, hot pressing, cold pressing, and drying. This complex battery production process results in low efficiency and high costs.

[0083] In view of this, the present application provides a battery cell having an electrode assembly with a laminated structure. The battery cell includes an electrode assembly and a heat shrink film. The electrode assembly includes a main body and a tab. The main body has two end faces arranged opposite to each other along a first direction and a circumferential surface connecting the two end faces. The tab is arranged on the end face. The heat shrink film is wrapped around the circumferential surface of the main body. The heat shrink film has a head end and a tail end in the circumferential direction, and the head end and the tail end are connected. By constraining the heat shrink film and shaping the electrode assembly based on the principle of heat shrinkage, the manufacturing efficiency of the battery cell can be improved and the manufacturing cost of the battery cell can be reduced.

[0084] The technical solutions described in the embodiments of the present application are applicable to battery cells, batteries, and electrical equipment using batteries.

[0085] Electrical equipment includes, but is not limited to, battery vehicles, electric vehicles, ships, and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc.

[0086] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0087] For example, FIG1 is a schematic diagram of the structure of a vehicle 1000 according to some embodiments of the present application. The vehicle 1000 may be a fuel vehicle, a gas vehicle, or a new energy vehicle. The new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle. A motor 300, a controller 200, and a battery 100 may be provided inside the vehicle 1000. The controller 200 is used to control the battery 100 to power the motor 300. For example, the battery 100 may be provided at the bottom, front, or rear of the vehicle 1000. The battery 100 may be used to power the vehicle 1000. For example, the battery 100 may serve as the operating power source of the vehicle 1000 and may be used for the circuit system of the vehicle 1000, such as for the starting, navigation, and operation power requirements of the vehicle 1000. In another embodiment of the present application, the battery 100 may serve not only as the operating power source of the vehicle 1000, but also as the driving power source of the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0088] To meet different power requirements, the battery 100 may include multiple battery cells 12, wherein the multiple battery cells 12 can be connected in series, in parallel, or in a hybrid connection. Hybrid connection refers to a mixture of series and parallel connections. The battery 100 may also be referred to as a battery pack. Optionally, multiple battery cells 12 may first be connected in series, in parallel, or in a hybrid connection to form a battery module, and multiple battery modules may then be connected in series, in parallel, or in a hybrid connection to form the battery 100. In other words, multiple battery cells 12 may directly form the battery 100, or they may first form battery modules, which may then form the battery 100.

[0089] For example, referring to FIG. 2 , FIG. 2 is an exploded view of a battery 100 according to some embodiments of the present application. The battery 100 may include a plurality of battery cells 12. The battery 100 may also include a housing 11 having a hollow interior, and the plurality of battery cells 12 are housed within the housing 11. As shown in FIG. 2 , these are referred to herein as a first portion 111 and a second portion 112, respectively. The first portion 111 and the second portion 112 are fastened together. The shapes of the first portion 111 and the second portion 112 may be determined based on the combined shape of the plurality of battery cells 12. The first portion 111 and the second portion 112 may each have a single opening. For example, the first portion 111 and the second portion 112 may each be a hollow rectangular parallelepiped, each with only one open face. The opening of the first portion 111 and the opening of the second portion 112 are arranged opposite each other, and the first portion 111 and the second portion 112 are fastened together to form the housing 11 having a closed chamber. The plurality of battery cells 12 are then arranged in parallel, in series, or in a mixed configuration and then placed within the housing 11 formed by the fastening of the first portion 111 and the second portion 112.

[0090] Optionally, the battery 100 may also include other structures, which are not described in detail here. For example, the battery may also include a busbar assembly, which is used to electrically connect multiple battery cells 12, such as in parallel, series, or mixed connection. Specifically, the busbar assembly can achieve electrical connection between the battery cells 12 by connecting to the electrode terminals 125 of the battery cells 12. Furthermore, the busbar assembly can be fixed to the electrode terminals 125 of the battery cells 12 by welding. The electrical energy of the multiple battery cells 12 can be further led out through the casing 11 via a conductive mechanism.

[0091] The number of battery cells 12 can be set to any value according to different power requirements. Multiple battery cells 12 can be connected in series, parallel, or in a hybrid manner to achieve a larger capacity or power. Since the number of battery cells 12 included in each battery 100 may be large, for ease of installation, the battery cells 12 can be grouped, and each group of battery cells 12 constitutes a battery module. The number of battery cells 12 included in a battery module is not limited and can be set according to requirements. The battery 100 may include multiple battery modules, which can be connected in series, parallel, or in a hybrid manner.

[0092] As shown in FIG3 , the battery cell 12 includes one or more electrode assemblies 122 and a housing 121 . The housing 121 may include a shell 1212 , wherein the multiple walls of the shell 1212, i.e., the multiple walls of the shell 121, form a cavity that can be used to accommodate the electrode assemblies 122 . The shell 1212 is determined by the shape of the one or more electrode assemblies 122 after being assembled. For example, the shell 1212 may be a hollow cuboid, a cube, or a regular polyhedron, and one of the faces of the shell 1212 may have an opening so that the one or more electrode assemblies 122 can be placed in the shell 1212 . The shell 1212 is filled with an electrolyte, such as an electrolyte solution. In some embodiments, the battery cell 12 may further include an insulating film, which is used to wrap the electrode assembly 122 . One insulating film may cover one or more electrode assemblies 122 . For example, when multiple electrode assemblies 122 are accommodated in the accommodation space, one insulating film may cover multiple electrode assemblies 122 . In some cases, the insulating film may also be referred to as a protective film. In other embodiments, the heat shrink film 123 used to bind the electrode assembly 122 may also serve as an insulating film.

[0093] The battery cell 12 may also include two electrode terminals 125, which may be provided on the end cap 1211. The end cap 1211 is generally in the shape of a flat plate, and the two electrode terminals 125 are fixed to the flat surface of the end cap 1211. The two electrode terminals 125 are respectively a positive electrode terminal 125 and a negative electrode terminal 125. Each electrode terminal 125 is provided with a corresponding adapter 124, which is located between the end cap 1211 and the electrode assembly 122 and is used to electrically connect the electrode assembly 122 and the electrode terminal 125. In the battery cell 12, the electrode assembly 122 may be provided as a single electrode assembly or as multiple electrode assemblies according to actual use requirements. Multiple independent electrode assemblies 122 are provided in the battery cell 12.

[0094] According to some embodiments of the present application, referring to Figures 4-7 and 10 , a battery cell 12 includes an electrode assembly 122 and a heat shrink film 123. The electrode assembly 122 includes a main body 1221 and a tab 1222. The main body 1221 has a first end face 12211a and a second end face 12211b oppositely disposed along a first direction X, and a circumferential surface 12212 connecting the first end face 12211a and the second end face 12211b. The tab 1222 is disposed on the first end face 12211a and / or the second end face 12211b. The heat shrink film 123 is wrapped around the circumferential surface 12212 of the main body 1221 along the circumference. The heat shrink film 123 has a leading end 1231 and a trailing end 1232 circumferentially, with the leading end 1231 and the trailing end 1232 connected.

[0095] The first direction X is the direction in which the tab 1222 extends out of the main body 1221 .

[0096] In some embodiments, the tabs 1222 include a positive tab 1222a and a negative tab 1222b, with the positive tab 1222a disposed on the first end surface 12211a and the negative tab 1222b disposed on the second end surface 12211b. In other embodiments, the negative tab 1222b is disposed on the first end surface 12211a and the positive tab 1222a is disposed on the second end surface 12211b.

[0097] The electrode assembly 122 may include, but is not limited to, a wound electrode assembly or a laminated electrode assembly.

[0098] Electrode assembly 122 includes at least one positive electrode sheet, at least one separator, and at least one negative electrode sheet. The positive and negative electrode sheets are alternately stacked along a direction, with a separator disposed between each positive electrode sheet and its adjacent negative electrode sheet to form electrode assembly 122. When electrode assembly 122 includes multiple positive electrode sheets and multiple negative electrode sheets, the number of positive electrode sheets and the number of negative electrode sheets can be the same or different. For example, in some embodiments, referring to FIG. 4 , the positive and negative electrode sheets are stacked along a third direction Z.

[0099] The portions of the positive and negative electrode sheets containing active materials and the separator constitute the main body 1221 , and the portions of the positive and negative electrode sheets not containing active materials each constitute the tab 1222 .

[0100] 5 , the peripheral surface 12212 can be viewed as a surface where the first side surface 12212a, the third side surface 12212c, the second side surface 12212b, and the fourth side surface 12212d are connected end to end.

[0101] The heat shrink film 123 is a film that can be preheated and shrunk. The material of the heat shrink film 123 includes but is not limited to polyethylene (PE), polypropylene (PP), polyester (PVC), polyolefin shrink film (POF), etc.

[0102] The heat shrink film 123 may be a long strip of film. Referring to FIG. 4 , when the heat shrink film 123 is in an unfolded state, one end in the second direction Y is a leading end 1231 , and the other end in the second direction Y is a trailing end 1232 .

[0103] After being wound around the peripheral surface 12212 , the head end 1231 and the tail end 1232 may be connected by colloid or tape.

[0104] The head end 1231 and the tail end 1232 can be connected to any surface of the main body 1221 .

[0105] The heat shrink film 123 can be wrapped around the circumferential surface 12212 along the circumference of the main body 1221. Wrapping the heat shrink film 123 around the circumferential surface 12212 can reduce the gap between the heat shrink film 123 and the main body 1221, making the electrode assembly 122 more tightly bound and reducing the risk of the electrode assembly 122 falling apart. This in turn provides the electrode assembly 122 with greater structural stability. At the same time, the heat shrink film 123 wrapped around the circumferential surface 12212 can provide a certain insulation effect, to a certain extent replacing the traditional insulating film used to insulate and isolate the electrode assembly 122 from the housing 1212.

[0106] In the technical solution of the embodiment of the present application, the heat shrinkable film 123 is used to constrain and shape the electrode assembly 122 due to the principle of thermal shrinkage. On the one hand, the hot pressing and cold pressing processes of the battery cell 12 are omitted, the manufacturing efficiency of the battery cell 12 is improved, and the manufacturing cost of the battery cell 12 is reduced; on the other hand, the heat shrinkable film 123 can also be used to insulate and isolate the electrode assembly 122 from the outer shell 121 of the battery cell 12.

[0107] According to some embodiments of the present application, the head end 1231 and the tail end 1232 are bonded by colloid.

[0108] The colloid may be formed by coating glue on the head end 1231 and / or the tail end 1232 .

[0109] In the above solution, the manufacturing cost of the battery cell 12 can be reduced by bonding the head end 1231 and the tail end 1232 of the heat shrink film 123 with colloid.

[0110] According to some embodiments of the present application, please refer to Figures 4 to 7. In the first direction X, the main body 1221 has a first edge 12213 and a second edge 12214, a first gap 126a is provided between the heat shrink film 123 and the first edge 12213, and a second gap 126b is provided between the heat shrink film 123 and the second edge 12214.

[0111] There is a first gap 126 a between the heat shrink film 123 and the first edge 12213 , and a second gap 126 b between the heat shrink film 123 and the second edge 12214 , which means that the heat shrink film 123 does not completely cover the peripheral surface 12212 .

[0112] In some embodiments, referring to FIG. 7 , the battery cell 12 further includes a first adhesive tape 127 and a second adhesive tape 128 . The first adhesive tape 127 and the second adhesive tape 128 are disposed around the body 1221 along the circumference of the body 1221. The heat shrink film 123 has a first end 1236 and a second end 1237 in the first direction X. In the first direction X, one end of the first adhesive tape 127 is adhered to the first gap 126a, and the other end of the first adhesive tape 127 is adhered to the heat shrink film 123 to secure the first end 1236. In the first direction X, one end of the second adhesive tape 128 is adhered to the second gap 126b, and the other end of the second adhesive tape 128 is adhered to the heat shrink film 123 to secure the second end 1237.

[0113] In the above solution, due to the existence of the first gap 126a and the second gap 126b, the heat shrink film 123 does not completely cover the peripheral surface 12212 of the main body 1221 in the first direction X. In this way, while the heat shrink film 123 constrains the electrode assembly 122, it can also enable the battery cell 12 to have a higher volume energy density.

[0114] According to some embodiments of the present application, referring to FIG. 4 to FIG. 7 , in the first direction X, the first gap 126 a and the second gap 126 b have the same size.

[0115] In the first direction X, the first gap 126 a and the second gap 126 b have the same size, which means that the first gap 126 a and the second gap 126 b are symmetrically arranged about the center line of the main body 1221 in the first direction X.

[0116] In the above solution, by simultaneously providing the first gap 126 a and the second gap 126 b of the same size, the restraining force on the electrode assembly 122 can be substantially consistent, which is beneficial for the electrode assembly 122 to have higher structural stability.

[0117] According to some embodiments of the present application, the electrode assembly 122 is a laminated electrode assembly.

[0118] The stacking direction of the positive electrode sheets and the negative electrode sheets of the electrode assembly 122 is the third direction Z.

[0119] In the above solution, the internal stress of the laminated electrode assembly itself is relatively small, and the heat shrinkable film 123 has a better restraining and shaping effect on the laminated electrode assembly.

[0120] According to some embodiments of the present application, referring to Figures 4-7, the peripheral surface 12212 includes a first side surface 12212a and a second side surface 12212b disposed opposite each other along a second direction Y, and a third side surface 12212c and a fourth side surface 12212d disposed opposite each other along a third direction Z. The third direction Z is parallel to the stacking direction of the electrode assembly 122. The area of ​​the third side surface 12212c is greater than that of the first side surface 12212a. The second direction Y, the first direction X, and the third direction Z are perpendicular to each other. The leading end 1231 and the trailing end 1232 are connected to form a connecting portion 1233, which is located on the first side surface 12212a.

[0121] In some embodiments, the third side 12212c and the fourth side 12212d have the same area, and the first side 12212a and the second side 12212b have the same area. In other embodiments, the third side 12212c and the fourth side 12212d are the largest surfaces of the electrode assembly 122 .

[0122] In some embodiments, when the head end 1231 and the tail end 1232 are connected to form the connecting portion 1233 , the head end 1231 and the tail end 1232 are first overlapped on the first side 12212a , and then a glue is applied to the overlapping portion of the head end 1231 and the tail end 1232 to bond the head end 1231 and the tail end 1232 .

[0123] In the above solution, disposing the connecting portion 1233 on the first side surface 12212 a can make the third side surface 12212 c with a larger area have a higher flatness, which is beneficial to improving the volume energy density of the battery cell 12 .

[0124] According to some embodiments of the present application, referring to FIG. 4 and FIG. 8 , in the third direction Z, the size of the connecting portion 1233 is L1, and the size of the heat shrinkable film 123 is L2, satisfying: 0.3≤L1 / L2≤0.7.

[0125] The dimensions of the connecting portion 1233 and the heat shrink film 123 are both the dimensions of the heat shrink film 123 after it shrinks due to heat. In some embodiments, the dimensions of the connecting portion 1233 may be the dimensions of the overlapping portion of the head end 1231 and the tail end 1232 in the third direction Z. In other embodiments, the dimensions of the connecting portion 1233 may be the dimensions of the adhesive tape used to bond the head end 1231 and the tail end 1232 in the third direction Z.

[0126] The size of the heat shrink film 123 is the average distance between the upper surface and the lower surface of the heat shrink film 123 in the third direction Z after the heat shrink film 123 shrinks due to heat.

[0127] L1 / L2 can be any value between equal to or greater than 0.3 and equal to or less than 0.7, for example, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, or 0.7.

[0128] In the above scheme, when L1 / L2≥0.3, in the third direction Z, the ratio of the size of the connecting portion 1233 to the size of the heat shrink film 123 is large, the connection strength between the head end 1231 and the tail end 1232 is high, and after the heat shrink film 123 constrains the electrode assembly 122, the electrode assembly 122 is not easily deformed; when L1 / L2≤0.7, in the third direction Z, the ratio of the size of the connecting portion 1233 to the size of the heat shrink film 123 is small, the heat shrink film 123 occupies less space inside the battery cell 12, and the volume energy density of the battery cell 12 is high; therefore, when 0.3≤L1 / L2≤0.7, the battery cell 12 can have a higher energy density while having a higher connection strength between the head end 1231 and the tail end 1232.

[0129] According to some embodiments of the present application, referring to FIG. 4 , FIG. 6 and FIG. 8 , a first hole 1234 is provided on a portion of the heat shrinkable film 123 covering the first side surface 12212 a .

[0130] The shape of the first hole 1234 may include but is not limited to a circle, a semicircle, a polygon, etc.

[0131] The first hole 1234 may be pre-processed before the heat shrink film 123 covers the electrode assembly 122 .

[0132] The diameters of the first holes 1234 may be the same or different.

[0133] The first holes 1234 may be arranged in one or more rows. The number of first holes 1234 in each row may be one or more. In an embodiment where there are multiple first holes 1234, the multiple first holes 1234 may be arranged linearly, in a wavy pattern, or in a random pattern.

[0134] The first side surface 12212a and the second side surface 12212b are arranged opposite each other along the second direction Y. The third direction Z is parallel to the stacking direction of the electrode assembly 122. The second direction Y, the first direction X, and the third direction Z are perpendicular to each other, indicating that there is an interlayer gap on the first side surface 12212a of the electrode assembly 122. When injecting electrolyte into the battery cell 12, the electrolyte can enter the interior of the electrode assembly 122 not only from the side of the tab 1222 but also through the first hole 1234 and the interlayer gap, which helps improve the injection efficiency of the battery cell 12.

[0135] In the above scheme, when the battery cell 12 is injected, the electrolyte can flow into the electrode assembly 122 through the first hole 1234. The electrolyte inside the battery cell 12 is filled faster, which is beneficial to improving the injection efficiency of the battery cell 12 and also improving the wetting effect of the electrolyte on the electrode assembly 122.

[0136] According to some embodiments of the present application, referring to FIG. 4 , FIG. 6 and FIG. 8 , the diameter of the first hole 1234 is D1 , and in the third direction Z, the size of the heat shrinkable film 123 is L2 , satisfying: 0.3≤D1 / L2≤0.7.

[0137] The diameter of the first hole 1234 can be understood as the diameter of the circumscribed circle of the first hole 1234, that is, the diameter of the first hole 1234 is the diameter of the smallest circle that can enclose the first hole 1234. For example, in an embodiment where the first hole 1234 is a square hole, the diameter of the first hole 1234 is the length of the diagonal of the square hole.

[0138] D1 / L2 can be any value greater than or equal to 0.3 and less than or equal to 0.7, for example, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, or 0.7.

[0139] In the above scheme, when D1 / L2≥0.3, the ratio of the diameter of the first hole 1234 to the size of the heat shrink film 123 in the third direction Z is large, and the injection efficiency of the battery cell 12 is high; when D1 / L2≤0.7, the ratio of the diameter of the first hole 1234 to the size of the heat shrink film 123 in the third direction Z is small, the heat shrink film 123 has a high tensile strength, and after the heat shrink film 123 constrains the electrode assembly 122, the structural stability of the electrode assembly 122 is high; therefore, when 0.3≤D1 / L2≤0.7, the battery cell 12 can have a high injection efficiency while the electrode assembly 122 has a high structural stability.

[0140] According to some embodiments of the present application, please refer to Figures 4, 6 and 8, 3mm≤D1≤7mm, 5mm≤L2≤15mm.

[0141] D1 can be any value greater than or equal to 3 mm and less than or equal to 7 mm, for example, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, and 7 mm.

[0142] L2 can be any value greater than or equal to 5 mm and less than or equal to 15 mm, for example, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, and 15 mm.

[0143] In the above scheme, when D1 ≥ 3 mm, the diameter of the first hole 1234 is larger, and the battery cell 12 injection efficiency is higher. When D1 ≤ 7 mm, the diameter of the first hole 1234 is smaller, the heat shrink film 123 has higher tensile strength, and the electrode assembly 122 has higher structural stability. Therefore, when 3 mm ≤ D1 ≤ 7 mm, the battery cell 12 injection efficiency is higher while the electrode assembly 122 has higher structural stability. When L2 ≥ 5 mm, the heat shrink film 123 has a larger dimension in the third direction Z, and the heat shrink film 123 has a better restraining effect on the electrode assembly 122. When L2 ≤ 15 mm, the heat shrink film 123 has a smaller dimension in the third direction Z, and the battery cell 12 has a higher energy density. Therefore, when 5 mm ≤ L2 ≤ 15 mm, the electrode assembly 122 has a better restraining effect while the battery cell 12 has a higher energy density.

[0144] According to some embodiments of the present application, please refer to Figures 4, 6 and 8, 4mm≤D1≤6mm, 8mm≤L2≤12mm.

[0145] D1 can be any value greater than or equal to 4 mm and less than or equal to 6 mm, for example, 4 mm, 4.5 mm, 5 mm, 5.5 mm, and 6 mm.

[0146] L2 can be any value greater than or equal to 8 mm and less than or equal to 12 mm, for example, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, and 12 mm.

[0147] In the above solution, when D1 ≥ 4 mm, the liquid injection efficiency of the battery cell 12 can be further improved; when D1 ≤ 6 mm, the structural stability of the electrode assembly 122 can be further improved. Therefore, when 4 mm ≤ D1 ≤ 6 mm, the liquid injection efficiency of the battery cell 12 can be further improved while also further improving the structural stability of the electrode assembly 122. When L2 ≥ 8 mm, the restraining effect of the heat shrink film 123 on the electrode assembly 122 can be further improved; when L2 ≤ 12 mm, the energy density of the battery cell 12 can be further improved. Therefore, when 8 mm ≤ L2 ≤ 12 mm, the restraining effect of the heat shrink film 123 on the electrode assembly 122 can be further improved while also further improving the energy density of the battery cell 12.

[0148] According to some embodiments of the present application, referring to FIG. 6-FIG . 7 , the first hole 1234 and the connecting portion 1233 do not overlap.

[0149] The first hole 1234 does not overlap with the connecting portion 1233 , which means that the connecting portion 1233 does not block the first hole 1234 .

[0150] In the above solution, since the first hole 1234 and the connecting portion 1233 do not overlap, the connecting portion 1233 will not block the first hole 1234 , which is beneficial for further improving the liquid injection efficiency of the battery cell 12 .

[0151] According to some embodiments of the present application, referring to FIG. 4 , FIG. 6 and FIG. 8 , a plurality of first holes 1234 are provided, and the plurality of first holes 1234 are arranged at intervals along the first direction X.

[0152] When the total area of ​​the holes is constant, compared with a single hole with a larger area, multiple first holes 1234 are arranged at intervals along the first direction X, which means that there is also a heat shrink film 123 between adjacent first holes 1234. The heat shrink film 123 between two adjacent first holes 1234 can also provide a certain binding force to the electrode assembly 122 after shrinking due to heat, which is beneficial to improving the shaping effect of the electrode assembly 122.

[0153] In the above solution, by providing a plurality of first holes 1234 , the liquid injection efficiency of the battery cell 12 can be further improved.

[0154] According to some embodiments of the present application, referring to FIG. 4 and FIG. 9 , a portion of the heat shrink film 123 covering the second side surface 12212 b is provided with a second hole 1235 .

[0155] The shape of the second hole 1235 may include, but is not limited to, a circle, a semicircle, a polygon, and the like.

[0156] The second hole 1235 can be pre-processed before the heat shrink film 123 covers the electrode assembly 122 .

[0157] In some embodiments, the connecting portion 1233 is located on the first side 12212a. The portion of the heat shrink film 123 covering the first side 12212a is provided with a first hole 1234. The first hole 1234 does not overlap with the connecting portion 1233. The portion of the heat shrink film 123 covering the second side 12212b is provided with a second hole 1235. In this embodiment, since the connecting portion 1233 is located on the first side 12212a, the position of the second hole 1235 provided on the second side 12212b does not interfere with the connecting portion 1233, and thus the area of ​​the second hole 1235 can be set larger than the area of ​​the first hole 1234, which is beneficial to improving the injection efficiency of the battery cell 12.

[0158] The second holes 1235 may be arranged in one or more rows. The number of second holes 1235 in each row may be one or more. In an embodiment where the number of second holes 1235 is multiple, the plurality of second holes 1235 may be arranged linearly, in a wavy pattern, or in a random pattern.

[0159] The first side surface 12212a and the second side surface 12212b are arranged opposite each other along the second direction Y. The third direction Z is parallel to the stacking direction of the electrode assembly 122. The second direction Y, the first direction X, and the third direction Z are perpendicular to each other, indicating that there is an interlayer gap on the second side surface 12212b of the electrode assembly 122. When injecting electrolyte into the battery cell 12, the electrolyte can enter the interior of the electrode assembly 122 not only from the side of the tab 1222 but also through the second hole 1235 and the interlayer gap, which helps improve the injection efficiency of the battery cell 12.

[0160] In the above scheme, when the battery cell 12 is injected, the electrolyte can flow into the electrode assembly 122 through the second hole 1235. The electrolyte inside the battery cell 12 is filled faster, which is beneficial to improving the injection efficiency of the battery cell 12 and also improving the wetting effect of the electrolyte on the electrode assembly 122.

[0161] According to some embodiments of the present application, referring to FIG. 4 and FIG. 9 , the diameter of the second hole 1235 is D2 , and in the third direction Z, the size of the heat shrinkable film 123 is L2 , satisfying: 0.3≤D2 / L2<1.

[0162] The diameter of the second hole 1235 can be understood as the diameter of the circumscribed circle of the second hole 1235 , that is, the diameter of the second hole 1235 is the diameter of the smallest circle that can surround the second hole 1235 .

[0163] D2 / L2 can be any value greater than or equal to 0.3 and less than 1, for example, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, and 0.95.

[0164] In the above scheme, when D2 / L2≥0.3, the ratio of the diameter of the second hole 1235 to the size of the heat shrink film 123 in the third direction Z is large, and the injection efficiency of the battery cell 12 is high; when D2 / L2<1, the ratio of the diameter of the second hole 1235 to the size of the heat shrink film 123 in the third direction Z is small, the heat shrink film 123 has a high tensile strength, and after the heat shrink film 123 constrains the electrode assembly 122, the structural stability of the electrode assembly 122 is high; therefore, when 0.3≤D2 / L2<1, the battery cell 12 can have a high injection efficiency while the electrode assembly 122 has a high structural stability.

[0165] According to some embodiments of the present application, please refer to Figure 4 and Figure 9, 3mm≤D2<10mm, 5mm≤L2≤15mm.

[0166] D2 can be any value greater than or equal to 3 mm and less than 10 mm, for example, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, and 9.5 mm. L2 can be any value greater than or equal to 5 mm and less than or equal to 15 mm, for example, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, 12 mm, 12.5 mm, 13 mm, 13.5 mm, 14 mm, 14.5 mm, and 15 mm.

[0167] In the above scheme, when D2 ≥ 3mm, the diameter of the second hole 1235 is larger, and the injection efficiency of the battery cell 12 is higher. When D2 < 10mm, the diameter of the second hole 1235 is smaller, and the structural stability of the electrode assembly 122 is higher. Therefore, when 3mm ≤ D2 < 10mm, the battery cell 12 can have a high injection efficiency while the electrode assembly 122 has a high structural stability. When L2 ≥ 5mm, the dimension of the heat shrink film 123 in the third direction Z is larger, and the heat shrink film 123 has a better restraining effect on the electrode assembly 122. When L2 ≤ 15mm, the dimension of the heat shrink film 123 in the third direction Z is smaller, and the energy density of the battery cell 12 is higher. Therefore, when 5mm ≤ L2 ≤ 15mm, the electrode assembly 122 can have a good restraining effect while the battery cell 12 has a high energy density.

[0168] According to some embodiments of the present application, please refer to Figure 4 and Figure 8, 4mm≤D2≤8mm, 8mm≤L2≤12mm.

[0169] D2 can be any value greater than or equal to 4 mm and less than 8 mm, for example, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, and 8 mm. L2 can be any value greater than or equal to 8 mm and less than or equal to 12 mm, for example, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 10.5 mm, 11 mm, 11.5 mm, and 12 mm.

[0170] In the above solution, when D2 ≥ 4 mm, the liquid injection efficiency of the battery cell 12 can be further improved; when D2 ≤ 8 mm, the structural stability of the electrode assembly 122 can be further improved. Therefore, when 4 mm ≤ D2 ≤ 8 mm, the liquid injection efficiency of the battery cell 12 can be further improved while also further improving the structural stability of the electrode assembly 122. When L2 ≥ 8 mm, the restraining effect of the heat shrink film 123 on the electrode assembly 122 can be further improved; when L2 ≤ 12 mm, the energy density of the battery cell 12 can be further improved. Therefore, when 8 mm ≤ L2 ≤ 12 mm, the restraining effect of the heat shrink film 123 on the electrode assembly 122 can be further improved while also further improving the energy density of the battery cell 12.

[0171] According to some embodiments of the present application, referring to FIG. 4 and FIG. 8 , a plurality of second holes 1235 are provided, and the plurality of second holes 1235 are arranged at intervals along the first direction X.

[0172] When the total area of ​​the holes is constant, compared with a single hole with a larger area, multiple second holes 1235 are arranged at intervals along the first direction X, which means that there is also a heat shrink film 123 between adjacent second holes 1235. The heat shrink film 123 between two adjacent second holes 1235 can also provide a certain binding force to the electrode assembly 122 after shrinking due to heat, which is beneficial to improving the shaping effect of the electrode assembly 122.

[0173] In the above solution, by providing a plurality of second holes 1235 , the liquid injection efficiency of the battery cell 12 can be further improved.

[0174] According to some embodiments of the present application, referring to Figures 6 and 7 , the battery cell 12 further includes a first adhesive tape 127 and a second adhesive tape 128 . The first adhesive tape 127 and the second adhesive tape 128 are both disposed around the body 1221 along its circumference. The heat shrink film 123 has a first end 1236 and a second end 1237 in the first direction X. The first adhesive tape 127 is used to secure the first end 1236 to the body 1221. The second adhesive tape 128 is used to secure the second end 1237 to the body 1221.

[0175] The first adhesive tape 127 and the second adhesive tape 128 may be made of a material such as polypropylene.

[0176] In some embodiments, referring to FIG. 8 , after the heat shrink film 123 is wrapped around the circumferential surface 12212 of the main body 1221 , a gap is left between the first end 1236 and the second end 1237 and the edge of the main body 1221 in the first direction X. A portion of the first adhesive tape 127 and a portion of the second adhesive tape 128 can be bonded to the gap, while the remaining portions can be bonded to the heat shrink film 123 to secure the first end 1236 and the second end 1237 .

[0177] In the above solution, the first tape 127 and the second tape 128 respectively secure the first end 1236 and the second end 1237 to the main body 1221 , which reduces the risk of secondary shrinkage of the heat shrink film 123 during the subsequent drying process, thereby exposing the electrode assembly 122 . This helps improve the reliability of the battery cell 12 .

[0178] According to some embodiments of the present application, referring to FIG. 6 and FIG. 7 , the outer edge of the first tape 127 is flush with the first end surface 12211 a , and the outer edge of the second tape 128 is flush with the second end surface 12211 b .

[0179] The outer edge of the first adhesive tape 127 refers to an edge of the first adhesive tape 127 facing away from the second adhesive tape 128 in the first direction X.

[0180] The outer surface of the second adhesive tape 128 refers to an edge of the second adhesive tape 128 facing away from the first adhesive tape 127 in the first direction X.

[0181] In the above solution, since the outer edge of the first tape 127 will not exceed the first end face 12211a and the outer surface of the second tape 128 will not exceed the second end face 12211b, the risk of the first tape 127 blocking the first end face 12211a and the second tape 128 blocking the second end face 12211b, which may lead to reduced liquid injection efficiency of the battery cell 12 and worse wetting effect of the electrode assembly 122, can be reduced.

[0182] According to some embodiments of the present application, referring to Figures 4 and 6 , the tabs 1222 include a positive tab 1222a and a negative tab 1222b . Both the positive tab 1222a and the negative tab 1222b are disposed on the first end surface 12211a .

[0183] The positive electrode tab 1222a and the negative electrode tab 1222b are both arranged on the first end surface 12211a, which means that inside the battery cell 12, only a larger assembly space needs to be reserved on one side corresponding to the first end surface 12211a of the electrode assembly 122.

[0184] In the above solution, the positive electrode tab 1222 a and the negative electrode tab 1222 b are located on the same side of the electrode assembly 122 , which is beneficial for improving the energy density of the battery cell 12 in one direction.

[0185] According to some embodiments of the present application, the present application provides a battery 100 , which includes the battery cell 12 in one or more of the above embodiments.

[0186] In the above solution, manufacturing the battery cells 12 in one or more of the above embodiments has high manufacturing efficiency and low cost, which means that manufacturing the battery 100 including the above battery cells 12 can also have high manufacturing efficiency and low cost.

[0187] According to some embodiments of the present application, the present application provides an electrical device, which includes the battery cell 12 in one or more of the above embodiments, and the battery cell 12 is used to provide electrical energy; or, the electrical device includes the battery 100 in one or more of the above embodiments, and the battery 100 is used to provide electrical energy.

[0188] In the above solution, the manufacturing of the battery cells 12 or batteries 100 in one or more of the above embodiments has high manufacturing efficiency and low cost, which means that the manufacturing of electrical equipment including the battery cells 12 or batteries 100 can also have high manufacturing efficiency and low cost.

[0189] According to some embodiments of the present application, with reference to Figures 3 to 7, the present application provides a battery cell 12, which includes a housing 121, an electrode assembly 122, and a heat shrink film 123. The housing 121 has a storage space, and the electrode assembly 122 is accommodated in the storage space. The electrode assembly 122 is a laminated electrode assembly. The electrode assembly 122 includes a main body 1221 and a tab 1222. The main body 1221 has a first end face 12211a and a second end face 12211b arranged opposite to each other along a first direction X, and a peripheral surface 12212 connecting the first end face 12211a and the second end face 12211b. The tab 1222 includes a positive tab 1222a and a negative tab 1222b. The positive tab 1222a and the negative tab 1222b are both arranged on the first end face 12211a.

[0190] The heat shrink film 123 is wrapped around the circumferential surface 12212 along the circumference of the main body 1221. The circumferential surface 12212 has a first side surface 12212a and a second side surface 12212b relatively arranged along the second direction Y, and a third side surface 12212c and a fourth side surface 12212d relatively arranged along the third direction Z. The third direction Z is parallel to the stacking direction of the electrode assembly 122. The area of ​​the third side surface 12212c is equal to the area of ​​the fourth side surface 12212d and is the surface with the largest area of ​​the electrode assembly 122. The second direction Y, the first direction X and the third direction Z are perpendicular to each other.

[0191] The heat shrink film 123 has a head end 1231 and a tail end 1232 circumferentially. The head end 1231 and the tail end 1232 are bonded together by a colloid to form a connection portion 1233. The connection portion 1233 is located on the first side surface 12212a. By using the principle of heat shrinkage of the heat shrink film 123 to constrain and shape the electrode assembly 122, the hot pressing and cold pressing processes of the battery cell 12 are eliminated, thereby improving the manufacturing efficiency of the battery cell 12 and reducing the manufacturing cost of the battery cell 12.

[0192] The portion of the heat shrink film 123 covering the first side surface 12212a is provided with a first hole 1234. The first hole 1234 does not overlap with the connecting portion 1233. A plurality of first holes 1234 are provided, and the plurality of first holes 1234 are arranged at intervals along the first direction X. The portion of the heat shrink film 123 covering the second side surface 12212b is provided with a second hole 1235. A plurality of second holes 1235 are provided, and the plurality of second holes 1235 are arranged at intervals along the first direction X. When injecting liquid into the battery cell 12, the electrolyte can flow into the interior of the electrode assembly 122 through the first hole 1234 and the second hole 1235. The electrolyte inside the battery cell 12 is filled faster, which is beneficial to improving the injection efficiency of the battery cell 12, and can also improve the infiltration effect of the electrolyte on the electrode assembly 122.

[0193] The battery cell 12 also includes a first tape 127 and a second tape 128. Along the circumference of the main body 1221, the first tape 127 and the second tape 128 are both arranged around the main body 1221. The heat shrink film 123 has a first end 1236 and a second end 1237 in the first direction X. The first tape 127 is used to fix the first end 1236 to the main body 1221. The second tape 128 is used to fix the second end 1237 to the main body 1221. The outer edge of the first tape 127 is flush with the first end face 12211a, and the outer edge of the second tape 128 is flush with the second end face 12211b. The provision of the first tape 127 and the second tape 128 can reduce the risk of secondary shrinkage of the heat shrink film 123 in the subsequent drying process, resulting in exposure of the electrode assembly 122. This is conducive to improving the reliability of the battery cell 12.

[0194] 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 make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions 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, characterized in that, Comprising: An electrode assembly, including a main body and tab ears. The main body has a first end face and a second end face oppositely arranged in a first direction, and a peripheral surface connecting the first end face and the second end face. The tab ears are arranged on the first end face and / or the second end face. A heat shrinkable film is wrapped around the peripheral surface along the circumference of the main body. The heat shrinkable film has a leading end and a trailing end in the circumferential direction, and the leading end and the trailing end are connected.

2. The battery cell according to claim 1, wherein, The leading end and the trailing end are bonded by a colloid.

3. The battery cell according to claim 1 or 2, characterized in that, In the first direction, the main body has a first edge and a second edge. There is a first gap between the heat shrinkable film and the first edge, and a second gap between the heat shrinkable film and the second edge.

4. The battery cell according to claim 3, wherein, In the first direction, the sizes of the first gap and the second gap are the same.

5. The battery cell according to any one of claims 1-4, characterized in that, The electrode assembly is a laminated electrode assembly.

6. The battery cell according to claim 5, wherein, The peripheral surface has a first side face and a second side face oppositely arranged in a second direction, and a third side face and a fourth side face oppositely arranged in a third direction. The third direction is parallel to the lamination direction of the electrode assembly. The area of the third side face is larger than the area of the first side face. The second direction, the first direction, and the third direction are perpendicular to each other in pairs. The leading end and the trailing end are connected to form a connecting portion, and the connecting portion is located on the first side face.

7. The battery cell according to claim 6, characterized in that, In the third direction, the size of the connecting portion is L1, and the size of the heat shrinkable film is L2, satisfying: 0.3 ≤ L1 / L2 ≤ 0.

7.

8. The battery cell according to claim 6 or 7, characterized in that A first hole is provided in the portion of the heat shrinkable film covering the first side face.

9. The battery cell according to claim 8, wherein, The diameter of the first hole is D1. In the third direction, the size of the heat shrinkable film is L2, satisfying: 0.3 ≤ D1 / L2 ≤ 0.

7.

10. The battery cell according to claim 9, wherein, 3mm ≤ D1 ≤ 7mm, 5mm ≤ L2 ≤ 15mm.

11. The battery cell according to claim 10, wherein 4mm ≤ D1 ≤ 6mm, 8mm ≤ L2 ≤ 12mm.

12. The battery cell according to any one of claims 8-11, characterized in that, The first hole does not overlap with the connecting portion.

13. The battery cell according to any one of claims 8 - 12, characterized in that, A plurality of the first holes are provided, and the plurality of first holes are arranged at intervals in the first direction.

14. The battery cell according to any one of claims 6-13, characterized in that, A second hole is provided in the portion of the heat shrinkable film covering the second side face.

15. The battery cell according to claim 14, wherein, The diameter of the second hole is D2. In the third direction, the size of the heat shrinkable film is L2, satisfying: 0.3 ≤ D2 / L2 < 1.

16. The battery cell according to claim 15, characterized in that, 3mm ≤ D2 < 10mm, 5mm ≤ L2 ≤ 15mm.

17. The battery cell according to claim 16, wherein, 4mm ≤ D2 ≤ 8mm, 8mm ≤ L2 ≤ 12mm.

18. The battery cell according to any one of claims 14-17, characterized in that, A plurality of the second holes are provided, and the plurality of second holes are arranged at intervals in the first direction.

19. The battery cell according to any one of claims 1-18, characterized in that, The battery cell further includes a first tape and a second tape. Along the circumference of the main body, both the first tape and the second tape are wound around the main body. The heat shrinkable film has a first end and a second end in the first direction. The first tape is used to fix the first end to the main body, and the second tape is used to fix the second end to the main body.

20. The battery cell according to claim 19, wherein, In the first direction, the outer edge of the first tape is flush with the first end face, and the outer edge of the second tape is flush with the second end face.

21. The battery cell according to any one of claims 1-20, characterized in that, The tab ears include a positive tab ear and a negative tab ear. Both the positive tab ear and the negative tab ear are arranged on the first end face.

22. A battery, characterized in that, Including the battery cell according to any one of claims 1-21.

23. An electrical device, characterized in that, The electrical device includes a battery cell as described in any one of claims 1-21, and the battery cell is used to provide electrical energy; Alternatively, the electrical device includes a battery as described in claim 22, and the battery is used to provide electrical energy.

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