WO2025146095A1 - Battery cell, battery and electric device - Google Patents

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

This application claims priority to Chinese patent application 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

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

Energy conservation and emission reduction are the key to the sustainable development of the automobile industry. Electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in their development.

How to improve battery manufacturing efficiency is an urgent problem to be solved in battery technology.

Summary of the invention

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.

In a first aspect, the present application provides a battery cell, the battery cell comprising an electrode assembly and a heat shrink film. The electrode assembly comprises a main body and a pole ear, the main body having a first end face and a second end face arranged opposite to each other along a first direction and a peripheral surface connecting the first end face and the second end face, and the pole ear is arranged on the first end face and/or the second end face. The heat shrink film is wrapped around the peripheral surface along the circumference of the main body, and 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.

In the technical solution of the embodiment of the present application, the electrode assembly is constrained and shaped by the principle of heat shrinkage of the heat shrinkable film. On the one hand, the hot pressing and cold pressing processes of the battery cell are omitted, 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.

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

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.

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 provided between the heat shrinkable film and the first edge, and a second gap is provided between the heat shrinkable film and the second edge.

In the above solution, due to the existence of the first gap and the second gap, the heat shrinkable film does not completely cover the circumference of the main body in the first direction. Thus, while the heat shrinkable film binds the electrode assembly, the battery cell can also have a higher volume energy density.

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

In the above scheme, 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 a higher structural stability.

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

In the above scheme, the internal stress of the laminated electrode assembly itself is relatively small, and the heat shrinkable film has a better binding and shaping effect on the laminated electrode assembly.

In one or more embodiments of the first aspect, the peripheral surface has a first side surface and a second side surface arranged opposite to each other along a second direction, and a third side surface and a fourth side surface arranged opposite to 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 the area of the first side surface, and the second direction, the first direction and the third direction are perpendicular to each other. The head end and the tail end are connected to form a connecting portion, and the connecting portion is located on the first side surface.

In the above solution, arranging the connection 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.

In one or more embodiments of the first aspect, in the third direction, the size of the connecting portion is L ₁ , and the size of the heat shrinkable film is L ₂ , satisfying: 0.3≤L ₁ /L ₂ ≤0.7.

In the above scheme, when L ₁ /L ₂ ≥0.3, in the third direction, the ratio of the size of the connection 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 binds the electrode assembly; when L ₁ /L ₂ ≤0.7, in the third direction, the ratio of the size of the connection 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≤L ₁ /L ₂ ≤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.

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.

In the above scheme, when injecting liquid into the battery cell, the electrolyte can flow into the electrode assembly through the first hole, and 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.

In one or more embodiments of the first aspect, the diameter of the first hole is D ₁ , and in the third direction, the size of the heat shrinkable film is L ₂ , satisfying: 0.3≤D ₁ /L ₂ ≤0.7.

In the above scheme, when D ₁ /L ₂ ≥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 D ₁ /L ₂ ≤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 high tensile strength, and after the heat shrink film binds the electrode assembly, the structural stability of the electrode assembly is high; therefore, when 0.3≤D ₁ /L ₂ ≤0.7, the battery cell can have a high injection efficiency while the electrode assembly has a high structural stability.

In one or more embodiments of the first aspect, 3 mm ≤ _{D 1} ≤ 7 mm, 5 mm ≤ L ₂ ≤ 15 mm.

In the above scheme, when D ₁ ≥3mm, the diameter of the first hole is larger, and the injection efficiency of the battery cell is higher; when D ₁ ≤7mm, the diameter of the first hole is smaller, the heat shrink film has a higher tensile strength, and the structural stability of the electrode assembly is higher; therefore, when 3mm≤D ₁ ≤7mm, the battery cell can have a higher injection efficiency while the electrode assembly has a higher structural stability. When L ₂ ≥5mm, the size of the heat shrink film in the third direction is larger, and the heat shrink film has a better binding effect on the electrode assembly; when L ₂ ≤15mm, the size of the heat shrink film in the third direction is smaller, and the energy density of the battery cell is higher; therefore, when 5mm≤L ₂ ≤15mm, the electrode assembly can have a better binding effect while the battery cell has a higher energy density.

In one or more embodiments of the first aspect, 4 mm≤D ₁ ≤6 mm, 8 mm≤L ₂ ≤12 mm.

In the above scheme, when D ₁ ≥4mm, the liquid injection efficiency of the battery cell can be further improved; when D ₁ ≤6mm, the structural stability of the electrode assembly can be further improved; therefore, when 4mm≤D ₁ ≤6mm, the liquid injection efficiency of the battery cell can be further improved while the structural stability of the electrode assembly can be further improved. When L ₂ ≥8mm, the binding effect of the heat shrink film on the electrode assembly can be further improved; when L ₂ ≤12mm, the energy density of the battery cell can be further improved; therefore, when 8mm≤L ₂ ≤12mm, the binding effect of the heat shrink film on the electrode assembly can be further improved while the energy density of the battery cell can be further improved.

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

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.

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.

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

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

In the above scheme, when injecting liquid into the battery cell, the electrolyte can flow into the electrode assembly through the second hole, and 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.

In one or more embodiments of the first aspect, the diameter of the second hole is D ₂ , and in the third direction, the size of the heat shrinkable film is L ₂ , satisfying: 0.3≤D ₂ /L ₂ <1.

In the above scheme, when D ₂ /L ₂ ≥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 D ₂ /L ₂ <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 high tensile strength, and after the heat shrink film binds the electrode assembly, the structural stability of the electrode assembly is high; therefore, when 0.3≤D ₂ /L ₂ <1, the battery cell can have a high injection efficiency while the electrode assembly has a high structural stability.

In one or more embodiments of the first aspect, 3 mm ≤ _{D 2} <10 mm, 5 mm ≤ _{L 2} ≤15 mm.

In the above scheme, when D ₂ ≥3mm, the diameter of the second hole is larger, and the injection efficiency of the battery cell is higher; when D ₂ ＜10mm, the diameter of the second hole is smaller, and the structural stability of the electrode assembly is higher; therefore, when 3mm≤D ₂ ＜10mm, the battery cell can have a higher injection efficiency and the electrode assembly can have a higher structural stability. When L ₂ ≥5mm, the size of the heat shrink film in the third direction is larger, and the heat shrink film has a better binding effect on the electrode assembly; when L ₂ ≤15mm, the size of the heat shrink film in the third direction is smaller, and the energy density of the battery cell is higher; therefore, when 5mm≤L ₂ ≤15mm, the electrode assembly can have a better binding effect and the battery cell can have a higher energy density.

In one or more embodiments of the first aspect, 4 mm≤D ₂ ≤8 mm, 8 mm≤L ₂ ≤12 mm.

In the above scheme, when D ₂ ≥4mm, the liquid injection efficiency of the battery cell can be further improved; when D ₂ ≤8mm, the structural stability of the electrode assembly can be further improved; therefore, when 4mm≤D ₂ ≤8mm, the liquid injection efficiency of the battery cell can be further improved while the structural stability of the electrode assembly can be further improved. When L ₂ ≥8mm, the binding effect of the heat shrink film on the electrode assembly can be further improved; when L ₂ ≤12mm, the energy density of the battery cell can be further improved; therefore, when 8mm≤L ₂ ≤12mm, the binding effect of the heat shrink film on the electrode assembly can be further improved while the energy density of the battery cell can be further improved.

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.

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

In one or more embodiments of the first aspect, the battery cell further includes a first tape and a second tape. Along the circumference of the main body, the first tape and the second tape are both arranged around the main body. The heat shrink 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. The second tape is used to fix the second end to the main body.

In the above solution, the first adhesive tape and the second adhesive tape respectively fix the first end and the second end to the main body, which can reduce the risk of secondary shrinkage of the heat shrink film in the subsequent drying process, resulting in exposure of the electrode assembly, which is conducive to improving the reliability of the battery cell.

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.

In the above scheme, 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.

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

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.

In a second aspect, the present application provides a battery, which includes a battery cell in one or more of the above-mentioned embodiments.

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

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.

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

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

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

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

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

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

FIG4 is an isometric view of a partial structure of a battery cell according to some embodiments of the present application, showing a heat shrinkable film in an unfolded state;

FIG5 is a schematic diagram of the structure of an electrode assembly in some embodiments of the present application;

FIG6 is an isometric view of a portion of the structure of a battery cell according to some embodiments of the present application;

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

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

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

FIG. 10 is an isometric view of a portion of the structure of a battery cell according to some other embodiments of the present application.

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

1000-vehicle; 200-controller; 300-motor; 100-battery; 11-housing; 111-first part; 112-second part; 12-battery cell; 121-housing; 1211-end cover; 1212-housing; 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

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

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

In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

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

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).

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

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

In the present 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, etc. The shape of the battery cell may include but is not limited to a cylinder, a flat body, a rectangular parallelepiped or other shapes, etc. The battery cell may include but is not limited to a cylindrical battery cell, a square battery cell, a soft-pack battery cell and a blade battery cell according to the packaging method.

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 casing for encapsulating one or more battery cells. The casing can reduce the risk of liquid or other foreign matter affecting the charging or discharging of the battery cells.

The following will mainly focus on the rectangular battery cell. 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.

In a common 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, and the end cap closes an opening of the shell to define a receiving space for receiving the electrode assembly.

The electrode assembly is contained in the containing space, and the electrode assembly includes 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 positive electrode collector not coated with the positive electrode active material layer protrudes from the positive electrode collector coated with the positive electrode active material layer, and the positive electrode collector not coated with the positive electrode active material layer serves as a positive electrode ear. 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 negative electrode collector not coated with the negative electrode active material layer protrudes from the negative electrode collector coated with the negative electrode active material layer, and the negative electrode collector not coated with the negative electrode active material layer serves as a negative electrode ear. 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 pass a large current without melting, the number of positive tabs is multiple and stacked together, and the number of negative tabs is multiple and stacked together. In addition, the forming method of the electrode assembly may include but is not limited to winding or lamination. For example, the lamination process is a process of stacking the positive electrode sheet, the negative electrode sheet and the separator to form an electrode assembly.

When the electrode assembly is placed in the shell, in order to reduce the risk of the electrode assembly being scratched by the shell, and to insulate the electrode assembly and the wall of the shell, the outer surface of the electrode assembly is generally coated with an insulating film. The insulating film is generally soft and has good flexibility. An insulating film can cover one or more electrode assemblies. Exemplarily, when multiple electrode assemblies are accommodated in the accommodation space, one insulating film can cover multiple electrode assemblies.

The tab generally leads the electrical energy of the electrode assembly by being electrically connected to a conductive member. In some cases, the conductive member is a transition piece connecting the tab and the electrode terminal. In other cases, the conductive member is an electrode terminal.

The electrode terminals generally include a positive electrode terminal and a negative electrode terminal. For a rectangular battery cell, the electrode terminals are generally provided at the end cap portion. In some other cases, the electrode terminals may also be provided at the housing portion. Multiple battery cells are connected in series and/or in parallel via the electrode terminals for various applications.

The development of battery technology must take into account many 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, the manufacturing efficiency of the battery must also be considered.

After the electrode assembly is stacked or wound, it needs to go through shaping, drying and other processes before it can be put into the shell. Usually, the electrode assembly needs to go through at least one rolling process, hot pressing process, cold pressing process and drying before it can be put into the shell. Battery production has many processes, low efficiency and high cost.

In view of this, the present application provides a battery cell, wherein the electrode assembly is a laminated structure. The battery cell includes an electrode assembly and a heat shrinkable film, wherein the electrode assembly includes a main body and a pole ear, wherein 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, and the pole ear is arranged on the end face. The heat shrinkable film is wrapped around the circumferential surface along the circumference of the main body, and the heat shrinkable 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 shrinkable film by the principle of heat shrinkage and shaping the electrode assembly, the manufacturing efficiency of the battery cell can be improved and the manufacturing cost of the battery cell can be reduced.

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

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.

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.

For example, FIG. 1 is a schematic diagram of the structure of a vehicle 1000 in 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, etc. 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, a 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 be used as an operating power source for the vehicle 1000, for the circuit system of the vehicle 1000, for example, for the working power demand during the start, navigation and operation of the vehicle 1000. In another embodiment of the present application, the battery 100 may not only be used as an operating power source for the vehicle 1000, but also as a driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

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

For example, please refer to FIG. 2, which is an exploded view of a battery 100 in some embodiments of the present application. The battery 100 may include a plurality of battery cells 12. The battery 100 may also include a box 11, the interior of the box 11 is a hollow structure, and a plurality of battery cells 12 are accommodated in the box 11. As shown in FIG. 2, they are respectively referred to as the first part 111 and the second part 112, and the first part 111 and the second part 112 are buckled together. The shapes of the first part 111 and the second part 112 can be determined according to the shapes of the combination of the plurality of battery cells 12, and the first part 111 and the second part 112 may each have an opening. For example, the first part 111 and the second part 112 may both be hollow cuboids and each has only one face as an opening face, the opening of the first part 111 and the opening of the second part 112 are arranged oppositely, and the first part 111 and the second part 112 are buckled together to form a box 11 with a closed chamber. After the plurality of battery cells 12 are connected in parallel, in series, or in a mixed combination, they are placed in the box 11 formed after the first part 111 and the second part 112 are buckled.

Optionally, the battery 100 may also include other structures, which are not described one by one here. For example, the battery may also include a busbar, which is used to realize electrical connection between multiple battery cells 12, such as parallel connection, series connection or mixed connection. Specifically, the busbar can realize electrical connection between battery cells 12 by connecting the electrode terminals 125 of the battery cells 12. Further, the busbar can be fixed to the electrode terminals 125 of the battery cells 12 by welding. The electrical energy of multiple battery cells 12 can be further led out through the box 11 through the conductive mechanism.

According to different power requirements, the number of battery cells 12 can be set to any value. Multiple battery cells 12 can be connected in series, parallel or hybrid 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 the battery module is not limited and can be set according to demand. The battery 100 may include multiple battery modules, which can be connected in series, parallel or hybrid.

As shown in FIG. 3 , the battery cell 12 includes one or more electrode assemblies 122 and a shell 121. The shell 121 may include a shell 1212, and multiple walls of the shell 1212, that is, multiple walls of the shell 121, form a cavity, which can be used to accommodate the electrode assembly 122. The shell 1212 is determined according to the shape of one or more electrode assemblies 122 after being combined. For example, the shell 1212 may be a hollow cuboid or a cube or a regular polyhedron, and one of the faces of the shell 1212 has an opening so that 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. In some embodiments, the battery cell 12 may also include an insulating film, which is used to wrap the electrode assembly 122, and one insulating film may cover one or more electrode assemblies 122. Exemplarily, 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 called 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.

The battery cell 12 may also include two electrode terminals 125, which may be disposed 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 on the flat surface of the end cap 1211, and 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, according to actual use requirements, the electrode assembly 122 may be provided as a single one, or as a plurality of ones, and a plurality of independent electrode assemblies 122 are provided in the battery cell 12.

According to some embodiments of the present application, please refer to FIGS. 4-7 and 10 , the 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 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 is arranged on the first end face 12211a and/or the second end face 12211b. The heat shrink film 123 is wrapped around the peripheral surface 12212 along the circumference of the main body 1221. The heat shrink film 123 has a head end 1231 and a tail end 1232 in the circumferential direction, and the head end 1231 and the tail end 1232 are connected.

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

In some embodiments, the tab 1222 includes a positive tab 1222a and a negative tab 1222b, wherein the positive tab 1222a is disposed on the first end surface 12211a and the negative tab 1222b is 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.

The electrode assembly 122 may include, but is not limited to, a wound-type electrode assembly or a stacked-type electrode assembly.

The electrode assembly 122 includes at least one positive electrode sheet, at least one separator and at least one negative electrode sheet. The positive electrode sheets and the negative electrode sheets are alternately stacked in one direction. A separator is provided between each positive electrode sheet and the negative electrode sheet adjacent thereto to form the electrode assembly 122. When the electrode assembly 122 includes a plurality of positive electrode sheets and a plurality of negative electrode sheets, the number of the positive electrode sheets and the number of the negative electrode sheets may be the same or different. For example, in some embodiments, referring to FIG. 4 , the positive electrode sheets and the negative electrode sheets are stacked in a third direction Z.

The parts of the positive electrode sheet and the negative electrode sheet having active materials and the separator constitute the main body 1221 , and the parts of the positive electrode sheet and the negative electrode sheet not having active materials each constitute the tab 1222 .

5 , the peripheral surface 12212 can be regarded 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.

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

The heat shrinkable film 123 may be a long strip of film. Referring to FIG. 4 , when the heat shrinkable film 123 is in an unfolded state, one end in the second direction Y is a head end 1231 , and the other end in the second direction Y is a tail end 1232 .

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

The head end 1231 and the tail end 1232 may be connected to any surface of the main body 1221 .

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 in a winding manner can reduce the gap between the heat shrink film 123 and the main body 1221, so that the electrode assembly 122 can be more tightly bound, reducing the risk of the electrode assembly 122 being scattered. In this way, the electrode assembly 122 has a higher structural stability. At the same time, the heat shrink film 123 can play a certain insulating effect after being wrapped around the circumferential surface 12212, and can replace the traditional insulating film used to insulate and isolate the electrode assembly 122 and the shell 1212 to a certain extent.

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.

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

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

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.

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 shrinkable film 123 and the first edge 12213, and a second gap 126b is provided between the heat shrinkable film 123 and the second edge 12214.

There is a first gap 126 a between the heat shrink film 123 and the first edge 12213 , and there is 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 .

In some embodiments, referring to FIG. 7 , the battery cell 12 further includes a first tape 127 and a second tape 128, and along the circumference of the main body 1221, the first tape 127 and the second tape 128 are both disposed 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. In the first direction X, one end of the first tape 127 is bonded to the first gap 126a, and the other end of the first tape 127 is bonded to the heat shrink film 123 to fix the first end 1236. In the first direction X, one end of the second tape 128 is bonded to the second gap 126b, and the other end of the second tape 128 is bonded to the heat shrink film 123 to fix the second end 1237.

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, the battery cell 12 can also have a higher volume energy density.

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

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.

In the above solution, by simultaneously providing the first gap 126a and the second gap 126b 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 a higher structural stability.

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

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

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 binding and shaping effect on the laminated electrode assembly.

According to some embodiments of the present application, please refer to FIGS. 4-7 , the peripheral surface 12212 has a first side surface 12212a and a second side surface 12212b arranged oppositely along the second direction Y, and a third side surface 12212c and a fourth side surface 12212d arranged oppositely 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 greater than the area of the first side surface 12212a, and the second direction Y, the first direction X and the third direction Z are perpendicular to each other. The head end 1231 and the tail end 1232 are connected to form a connecting portion 1233, and the connecting portion 1233 is located on the first side surface 12212a.

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

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 colloid 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 .

In the above solution, the connection portion 1233 is disposed on the first side surface 12212 a so that the third side surface 12212 c with a larger area has a higher flatness, which is beneficial to improving the volume energy density of the battery cell 12 .

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 L ₁ , and the size of the heat shrinkable film 123 is L ₂ , satisfying: 0.3≤L ₁ /L ₂ ≤0.7.

The size of the connecting portion 1233 and the size of the heat shrinkable film 123 are both the sizes of the heat shrinkable film 123 after shrinking by heat. In some embodiments, the size of the connecting portion 1233 may be the size of the overlapping portion of the head end 1231 and the tail end 1232 in the third direction Z. In other embodiments, the size of the connecting portion 1233 may be the size of the tape used to bond the head end 1231 and the tail end 1232 in the third direction Z.

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

L ₁ /L ₂ may 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.

In the above scheme, when L ₁ /L ₂ ≥0.3, in the third direction Z, the ratio of the size of the connecting portion 1233 to the size of the heat shrinkable film 123 is large, the connection strength between the head end 1231 and the tail end 1232 is high, and after the heat shrinkable film 123 restrains the electrode assembly 122, the electrode assembly 122 is not easily deformed; when L ₁ /L ₂ ≤0.7, in the third direction Z, the ratio of the size of the connecting portion 1233 to the size of the heat shrinkable film 123 is small, the heat shrinkable film 123 occupies a small space inside the battery cell 12, and the volume energy density of the battery cell 12 is high; therefore, when 0.3≤L ₁ /L ₂ ≤0.7, the battery cell 12 can have a high energy density while having a high connection strength between the head end 1231 and the tail end 1232.

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

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

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

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

The first holes 1234 may be arranged in one row or in multiple rows. The number of the first holes 1234 in each row may be one or more. In the embodiment where the number of the first holes 1234 is multiple, the multiple first holes 1234 may be arranged linearly, in a wavy shape, or in a disorderly arrangement.

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

In the above scheme, when injecting liquid into the battery cell 12, 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.

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 D ₁ , and in the third direction Z, the size of the heat shrinkable film 123 is L ₂ , satisfying: 0.3≤D ₁ /L ₂ ≤0.7.

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 surround 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.

D ₁ /L ₂ may 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.

In the above scheme, when D ₁ /L ₂ ≥0.3, the ratio of the diameter of the first hole 1234 to the size of the heat shrinkable film 123 in the third direction Z is large, and the injection efficiency of the battery cell 12 is high; when D ₁ /L ₂ ≤0.7, the ratio of the diameter of the first hole 1234 to the size of the heat shrinkable film 123 in the third direction Z is small, the heat shrinkable film 123 has a high tensile strength, and after the heat shrinkable film 123 binds the electrode assembly 122, the structural stability of the electrode assembly 122 is high; therefore, when 0.3≤D ₁ /L ₂ ≤0.7, the battery cell 12 can have a high injection efficiency while the electrode assembly 122 has a high structural stability.

According to some embodiments of the present application, referring to FIG. 4 , FIG. 6 and FIG. 8 , 3 mm ≤ _{D 1} ≤ 7 mm, 5 mm ≤ _{L 2} ≤ 15 mm.

_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.

_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.

In the above scheme, when D ₁ ≥3mm, the diameter of the first hole 1234 is larger, and the injection efficiency of the battery cell 12 is higher; when D ₁ ≤7mm, the diameter of the first hole 1234 is smaller, the heat shrink film 123 has a higher tensile strength, and the structural stability of the electrode assembly 122 is higher; therefore, when 3mm≤D ₁ ≤7mm, the battery cell 12 can have a higher injection efficiency and the electrode assembly 122 can have a higher structural stability. When L ₂ ≥5mm, the size of the heat shrink film 123 in the third direction Z is larger, and the heat shrink film 123 has a better binding effect on the electrode assembly 122; when L ₂ ≤15mm, the size 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≤L ₂ ≤15mm, the electrode assembly 122 can have a better binding effect and the battery cell 12 can have a higher energy density.

According to some embodiments of the present application, referring to FIG. 4 , FIG. 6 and FIG. 8 , 4 mm ≤ _{D 1} ≤ 6 mm, 8 mm ≤ _{L 2} ≤ 12 mm.

_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.

_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.

In the above scheme, when D ₁ ≥4mm, the liquid injection efficiency of the battery cell 12 can be further improved; when D ₁ ≤6mm, the structural stability of the electrode assembly 122 can be further improved; therefore, when 4mm≤D ₁ ≤6mm, the liquid injection efficiency of the battery cell 12 can be further improved while further improving the structural stability of the electrode assembly 122. When L ₂ ≥8mm, the restraining effect of the heat shrinkable film 123 on the electrode assembly 122 can be further improved; when L ₂ ≤12mm, the energy density of the battery cell 12 can be further improved; therefore, when 8mm≤L ₂ ≤12mm, the restraining effect of the heat shrinkable film 123 on the electrode assembly 122 can be further improved while further improving the energy density of the battery cell 12.

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

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

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 to further improve the liquid injection efficiency of the battery cell 12 .

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 along the first direction X at intervals.

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 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.

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.

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

The shape of the second hole 1235 may include but is not limited to a circle, a semicircle, a polygon, etc.

The second hole 1235 may be pre-processed before the heat shrink film 123 covers the electrode assembly 122 .

In some embodiments, the connection 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 connection 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 connection portion 1233 is located on the first side 12212a, the position of the second hole 1235 provided on the second side 12212b will not interfere with the connection 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.

The second holes 1235 may be arranged in one row or in multiple rows. The number of the second holes 1235 in each row may be one or more. In the embodiment where the number of the second holes 1235 is multiple, the multiple second holes 1235 may be arranged linearly, in a wavy shape, or in a disorderly arrangement.

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

In the above scheme, when injecting liquid into the battery cell 12, 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.

According to some embodiments of the present application, referring to FIG. 4 and FIG. 9 , the diameter of the second hole 1235 is D ₂ , and in the third direction Z, the size of the heat shrinkable film 123 is L ₂ , satisfying: 0.3≤D ₂ /L ₂ <1.

The diameter of the second hole 1235 may 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 .

D ₂ /L ₂ 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, or 0.95.

In the above scheme, when D ₂ /L ₂ ≥0.3, the ratio of the diameter of the second hole 1235 to the size of the heat shrinkable film 123 in the third direction Z is large, and the injection efficiency of the battery cell 12 is high; when D ₂ /L ₂ <1, the ratio of the diameter of the second hole 1235 to the size of the heat shrinkable film 123 in the third direction Z is small, the heat shrinkable film 123 has a high tensile strength, and after the heat shrinkable film 123 binds the electrode assembly 122, the structural stability of the electrode assembly 122 is high; therefore, when 0.3≤D ₂ /L ₂ <1, the battery cell 12 can have a high injection efficiency while the electrode assembly 122 has a high structural stability.

According to some embodiments of the present application, referring to FIG. 4 and FIG. 9 , 3 mm ≤ _{D 2} ＜10 mm, 5 mm ≤ _{L 2} ≤15 mm.

_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, 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, 15 mm.

In the above scheme, when D ₂ ≥3mm, the diameter of the second hole 1235 is larger, and the injection efficiency of the battery cell 12 is higher; when D ₂ <10mm, the diameter of the second hole 1235 is smaller, and the structural stability of the electrode assembly 122 is higher; therefore, when 3mm≤D ₂ <10mm, the battery cell 12 can have a higher injection efficiency and the electrode assembly 122 can have a higher structural stability. When L ₂ ≥5mm, the size of the heat shrink film 123 in the third direction Z is larger, and the heat shrink film 123 has a better binding effect on the electrode assembly 122; when L ₂ ≤15mm, the size 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≤L ₂ ≤15mm, the electrode assembly 122 can have a better binding effect and the battery cell 12 can have a higher energy density.

According to some embodiments of the present application, referring to FIG. 4 and FIG. 8 , 4 mm ≤ _{D 2} ≤ 8 mm, and 8 mm ≤ _{L 2} ≤ 12 mm.

_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, 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, 12 mm.

In the above scheme, when D ₂ ≥4mm, the liquid injection efficiency of the battery cell 12 can be further improved; when D ₂ ≤8mm, the structural stability of the electrode assembly 122 can be further improved; therefore, when 4mm≤D ₂ ≤8mm, the liquid injection efficiency of the battery cell 12 can be further improved while the structural stability of the electrode assembly 122 can be further improved. When L ₂ ≥8mm, the binding effect of the heat shrinkable film 123 on the electrode assembly 122 can be further improved; when L ₂ ≤12mm, the energy density of the battery cell 12 can be further improved; therefore, when 8mm≤L ₂ ≤12mm, the binding effect of the heat shrinkable film 123 on the electrode assembly 122 can be further improved while the energy density of the battery cell 12 can be further improved.

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 along the first direction X at intervals.

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 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.

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.

According to some embodiments of the present application, referring to FIG. 6 and FIG. 7 , the battery cell 12 further 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 material of the first adhesive tape 127 and the second adhesive tape 128 may include polypropylene or the like.

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 , in the first direction X, there is a gap 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 tape 127 and a portion of the second tape 128 can be bonded to the gap, and the other portion can be bonded to the heat shrink film 123 to fix the first end 1236 and the second end 1237 .

In the above solution, the first tape 127 and the second tape 128 respectively fix the first end 1236 and the second end 1237 to the main body 1221, which 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, thereby improving the reliability of the battery cell 12.

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 .

The outer edge of the first adhesive tape 127 refers to an edge of the first adhesive tape 127 in the first direction X that is away from the second adhesive tape 128 .

The outer surface of the second adhesive tape 128 refers to an edge of the second adhesive tape 128 in the first direction X that is away from the first adhesive tape 127 .

In the above scheme, 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 leads to reduced liquid injection efficiency of the battery cell 12 and poor wetting effect of the electrode assembly 122, can be reduced.

According to some embodiments of the present application, referring to Figure 4 and Figure 6, the electrode tab 1222 includes a positive electrode tab 1222a and a negative electrode tab 1222b. The positive electrode tab 1222a and the negative electrode tab 1222b are both disposed on the first end surface 12211a.

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 of the first end surface 12211a of the electrode assembly 122.

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 to improving the energy density of the battery cell 12 in one direction.

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.

In the above solution, manufacturing the battery cell 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 cell 12 can also have high manufacturing efficiency and low cost.

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.

In the above scheme, manufacturing the battery cell 12 or battery 100 in one or more of the above embodiments has high manufacturing efficiency and low cost, which means that manufacturing electrical equipment including the above battery cell 12 or battery 100 can also have high manufacturing efficiency and low cost.

According to some embodiments of the present application, with reference to FIGS. 3-7 , 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 pole ear 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, and the pole ear 1222 includes a positive pole ear 1222a and a negative pole ear 1222b. The positive pole ear 1222a and the negative pole ear 1222b are both arranged on the first end face 12211a.

The heat shrinkable 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.

The heat shrink film 123 has a head end 1231 and a tail end 1232 in the circumferential direction. The head end 1231 and the tail end 1232 are bonded by colloid to form a connection portion 1233. The connection portion 1233 is located on the first side surface 12212a. The heat shrink film 123 is constrained by the principle of heat shrinkage and the electrode assembly 122 is shaped, so that the hot pressing process and the cold pressing process 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.

The portion of the heat shrinkable 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 shrinkable 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, and 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.

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. It is beneficial to improve the reliability of the battery cell 12.

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

Claims (23)

A battery cell, characterized by comprising: An electrode assembly, comprising a main body and a tab, wherein the main body has a first end face and a second end face arranged opposite to each other along a first direction and a peripheral face connecting the first end face and the second end face, and the tab is arranged on the first end face and/or the second end face; A heat shrinkable film is wrapped around the circumferential surface along the circumferential direction of the main body, and the heat shrinkable film has a head end and a tail end in the circumferential direction, and the head end is connected to the tail end. The battery cell according to claim 1, wherein the head end and the tail end are bonded by colloid. 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, 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. The battery cell according to claim 3, characterized in that, in the first direction, the first gap and the second gap have the same size. The battery cell according to any one of claims 1 to 4, characterized in that the electrode assembly is a laminated electrode assembly. The battery cell according to claim 5, characterized in that the peripheral surface has a first side surface and a second side surface arranged opposite to each other along a second direction and a third side surface and a fourth side surface arranged opposite to 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 the area of the first side surface, and the second direction, the first direction and the third direction are perpendicular to each other; The head end and the tail end are connected to form a connecting portion, and the connecting portion is located on the first side surface. The battery cell according to claim 6, characterized in that, in the third direction, the size of the connecting portion is L ₁ , the size of the heat shrinkable film is L ₂ , and the relationship: 0.3≤L ₁ /L ₂ ≤0.7 is satisfied. The battery cell according to claim 6 or 7, characterized in that a first hole is provided in a portion of the heat shrinkable film covering the first side surface. The battery cell according to claim 8, characterized in that the diameter of the first hole is D ₁ , and in the third direction, the size of the heat shrinkable film is L ₂ , satisfying: 0.3≤D ₁ /L ₂ ≤0.7. The battery cell according to claim 9, characterized in that 3 mm ≤ _{D 1} ≤ 7 mm, and 5 mm ≤ L ₂ ≤ 15 mm. The battery cell according to claim 10, characterized in that 4 mm ≤ _{D 1} ≤ 6 mm, and 8 mm ≤ L ₂ ≤ 12 mm. The battery cell according to any one of claims 8 to 11, characterized in that the first hole and the connecting portion do not overlap. The battery cell according to any one of claims 8 to 12, characterized in that a plurality of the first holes are provided, and the plurality of the first holes are arranged at intervals along the first direction. The battery cell according to any one of claims 6 to 13, characterized in that a second hole is provided in a portion of the heat shrinkable film covering the second side surface. The battery cell according to claim 14, characterized in that a diameter of the second hole is D ₂ , and in the third direction, a size of the heat shrinkable film is L ₂ , satisfying: 0.3≤D ₂ /L ₂ <1. The battery cell according to claim 15, characterized in that 3 mm ≤ _{D 2} < 10 mm, and 5 mm ≤ L ₂ ≤ 15 mm. The battery cell according to claim 16, characterized in that 4 mm ≤ _{D 2} ≤ 8 mm, and 8 mm ≤ L ₂ ≤ 12 mm. The battery cell according to any one of claims 14 to 17, characterized in that a plurality of the second holes are provided, and the plurality of the second holes are arranged at intervals along the first direction. The battery cell according to any one of claims 1 to 18, characterized in that the battery cell further comprises a first adhesive tape and a second adhesive tape, and along the circumference of the main body, the first adhesive tape and the second adhesive tape are both arranged around the main body; The heat shrinkable film has a first end and a second end in the first direction, the first adhesive tape is used to fix the first end to the main body, and the second adhesive tape is used to fix the second end to the main body. The battery cell according to claim 19, characterized in that, in the first direction, the outer edge of the first tape is flush with the first end surface, and the outer edge of the second tape is flush with the second end surface. The battery cell according to any one of claims 1 to 20, characterized in that the tabs include a positive tab and a negative tab; The positive electrode tab and the negative electrode tab are both arranged on the first end surface. A battery, characterized by comprising the battery cell according to any one of claims 1 to 21. An electrical device, characterized in that the electrical device comprises a battery cell according to any one of claims 1 to 21, wherein the battery cell is used to provide electrical energy; Or, the electrical device includes a battery as described in claim 22, and the battery is used to provide electrical energy.