Battery cell, battery device, and electric device

Abstract

The application provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises a shell, an electrode assembly and an adhesive layer. The electrode assembly is accommodated in the shell. The electrode assembly is in a winding shape and comprises a first pole piece. An innermost circle of the first pole piece comprises oppositely arranged first and second flat portions. The adhesive layer is used to adhesively connect the first and second flat portions. The battery monomer provided by the application is beneficial to reduce the risk of folding or displacement of a diaphragm, thereby reducing the risk of internal short circuit of the battery monomer caused by contact between a positive pole piece and a negative pole piece, and improving the reliability of the battery monomer.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Battery cells are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] In the development of battery cell technology, in addition to improving the performance of battery cells, their reliability is also a crucial consideration. Therefore, improving the reliability of battery cells is a continuous challenge in battery cell technology. Summary of the Invention

[0004] This application provides a battery cell, a battery device, and an electrical device, which helps to improve the reliability of the battery cell.

[0005] This application is achieved through the following technical solution:

[0006] In a first aspect, the battery cell provided in the embodiments of this application includes a casing, an electrode assembly, and an adhesive layer. The electrode assembly is housed within the casing, is wound, and includes a first electrode sheet. The innermost ring of the first electrode sheet includes a first straight portion and a second straight portion disposed opposite to each other. The adhesive layer bonds and connects the first straight portion and the second straight portion.

[0007] The battery cell provided in this application embodiment uses an adhesive layer to bond the first straight portion and the second straight portion of the first electrode sheet. This reduces the risk of an opening in the innermost ring of the electrode assembly caused by the separation of the first straight portion and the second straight portion of the innermost first electrode sheet. It also reduces the risk of the separator folding or shifting relative to the electrode sheet. This, in turn, helps to reduce the risk of internal short circuits in the battery cell caused by contact between the positive and negative electrode sheets, and improves the reliability of the battery cell.

[0008] According to some embodiments of this application, the surface area of ​​the first straight portion and the second straight portion opposite to each other is S, and the surface area of ​​the first straight portion and the adhesive layer connection portion is S1, where 50% ≤ S1 / S ≤ 100%.

[0009] In the above scheme, by setting 50%≤S1 / S≤100%, it is beneficial to improve the bonding strength of the first straight part and the second straight part, and reduce the risk of cracking of the first straight part and the second straight part.

[0010] According to some embodiments of this application, 70% ≤ S1 / S ≤ 90%.

[0011] In the above scheme, by setting 70%≤S1 / S≤90%, it is beneficial to further improve the bonding strength of the first straight part and the second straight part, reduce the risk of cracking of the first straight part and the second straight part, and reduce the risk of adhesive layer overflowing to the end of the electrode assembly.

[0012] According to some embodiments of this application, the minimum thickness e of the adhesive layer satisfies: 10μm≤e≤200μm.

[0013] In the above scheme, by setting 10μm≤e≤200μm, it is beneficial to improve the bonding strength of the first straight part and the second straight part, reduce the risk of cracking of the first straight part and the second straight part, and also reduce the risk of adhesive layer overflowing to the end of the electrode assembly.

[0014] According to some embodiments of this application, 20μm≤e≤50μm.

[0015] In the above scheme, by setting 20μm≤e≤50μm, it is beneficial to further improve the bonding strength of the first straight part and the second straight part, reduce the risk of cracking of the first straight part and the second straight part, and also to further reduce the risk of the adhesive layer overflowing to the end of the electrode assembly.

[0016] According to some embodiments of this application, the melting point T of the adhesive layer is ≥170°C.

[0017] In the above scheme, by setting the melting point T of the adhesive layer to ≥170℃, it is beneficial to reduce the risk of the adhesive layer softening or melting during the normal operation of the battery cell, and to improve the structural stability of the adhesive layer, thereby improving the reliability of the bonding connection between the first straight part and the second straight part.

[0018] According to some embodiments of this application, the electrode assembly includes an electrode body and a tab, the tab extending from an end of the electrode body along a first direction. Along the first direction, the shortest distance d from the edge of the adhesive layer to the edge of the first straight portion satisfies: 2mm ≤ d ≤ 10mm.

[0019] In the above scheme, by setting 2mm≤d≤10mm, it is beneficial to improve the bonding strength of the first straight part and the second straight part, thereby reducing the risk of the first straight part and the second straight part splitting apart, and also reducing the risk of the adhesive layer overflowing from the first straight part and the second straight part.

[0020] According to some embodiments of this application, the first straight portion includes alternating adhesive and non-adhesive areas, and the adhesive layer is bonded to the adhesive area of ​​the first straight portion.

[0021] In the above scheme, the adhesive layer is distributed in a large area between the first flat part and the second flat part, which is beneficial to improving the bonding strength of the first flat part and the second flat part. It can also utilize the gaps between the non-adhesive areas to accommodate more electrolyte, and is beneficial to improving the wettability of the electrolyte to the electrode assembly, thereby improving the dynamic performance of the battery cell.

[0022] According to some embodiments of this application, the bonding area is distributed in a mesh or strip pattern.

[0023] The above scheme is beneficial for improving the wettability of the electrolyte to the electrode assembly, while also facilitating the forming process of the adhesive layer on the first electrode, which helps to simplify the process difficulty of the battery cell.

[0024] According to some embodiments of this application, the material of the adhesive layer includes polypropylene.

[0025] In the above scheme, polypropylene has a high melting point and good thermal conductivity. By including polypropylene in the adhesive layer, the structural stability of the adhesive layer can be improved, and the heat can be transferred away from the battery cell in a timely manner during operation.

[0026] Secondly, the battery device provided in the embodiments of this application includes the battery cell provided in any of the above embodiments.

[0027] The battery device provided in this application has the same technical effect as the battery cell provided in any of the above embodiments, and will not be described again here.

[0028] Thirdly, the electrical device provided in the embodiments of this application includes the battery device provided in the above embodiments, and the battery device is used to provide electrical energy.

[0029] The electrical device provided in this application embodiment has the same technical effect as the battery device provided in this application embodiment, and will not be described again here.

[0030] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0031] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1This is a schematic diagram of the vehicle structure provided in an embodiment of this application;

[0033] Figure 2 This is a schematic diagram of the structure of the battery device provided in the embodiments of this application;

[0034] Figure 3 This is a schematic diagram of the structure of a battery cell assembly in a battery device provided in an embodiment of this application;

[0035] Figure 4 This is a schematic diagram of the exploded structure of a single battery cell in a battery device provided in an embodiment of this application;

[0036] Figure 5 This is a cross-sectional view of the electrode assembly in a battery cell provided in an embodiment of this application.

[0037] Figure 6 This is a partial structural diagram of the first electrode in the unfolded state of a battery cell provided in an embodiment of this application.

[0038] The accompanying drawings are not necessarily drawn to scale.

[0039] Explanation of reference numerals in the attached figures:

[0040] 1-Vehicle; 1a-Motor; 1b-Controller;

[0041] 10 - Battery assembly; 11 - Housing; 111 - First sub-housing; 112 - Second sub-housing;

[0042] 20-Battery cell module;

[0043] 30-Battery cell; 31-Casing; 311-Housing shell; 312-End cap; 32-Electrode assembly; 321-Electrode body; 322-Taper; 33-Electrode terminal;

[0044] 40 - First electrode; 41 - First straight portion; 41a - Adhesive area; 41b - Non-adhesive area; 42 - Second straight portion;

[0045] 50 - Adhesive layer;

[0046] X - First direction. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0049] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0050] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0051] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0052] In this application, "multiple" refers to two or more (including two), and similarly, "multiple groups" refers to two or more (including two), and "multiple pieces" refers to two or more (including two).

[0053] The battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0054] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells; as an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells into a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0055] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0056] As an example, the battery cell assembly can be a battery module, which can be housed in a housing by fixing the battery module in the housing.

[0057] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0058] In some embodiments, the housing may be part of the vehicle's chassis structure. For example, a portion of the housing may be at least a part of the vehicle's floor, or a portion of the housing may be at least a part of the vehicle's crossbeams and longitudinal beams.

[0059] In some embodiments, the battery device may be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0060] In this embodiment of the application, the battery cell can be a secondary battery, which refers to a battery cell that can be recharged to activate the active materials and continue to be used after the battery cell has been discharged.

[0061] The battery cell may be, but is not limited to, lithium-ion battery, sodium-ion battery, sodium-lithium-ion battery, lithium metal battery, sodium metal battery, lithium-sulfur battery, magnesium-ion battery, nickel-metal hydride battery, nickel-cadmium battery, lead-acid battery, etc.

[0062] A single battery cell typically includes an electrode assembly. The electrode assembly includes a positive electrode, a negative electrode, and a separator. During the charging and discharging process of a single battery cell, active ions (such as lithium ions) repeatedly insert and extract between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, prevents short circuits while allowing active ions to pass through.

[0063] In some embodiments, the positive electrode may be a positive electrode sheet, which may include a positive electrode current collector and a positive electrode active material disposed on at least one surface of the positive electrode current collector.

[0064] As an example, the positive current collector has two surfaces opposite each other in its own thickness direction, and the positive active material is disposed on either or both of the two opposite surfaces of the positive current collector.

[0065] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be made of stainless steel, copper, aluminum, carbon electrodes, carbon, nickel, or titanium with a silver-plated surface. The composite current collector may include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0066] As an example, the positive electrode active material may include at least one of the following materials: lithium phosphate, lithium transition metal oxide, and their respective modified compounds. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for battery cells may also be used.

[0067] In some embodiments, the negative electrode may be a negative electrode sheet, and the negative electrode sheet may include a negative electrode current collector.

[0068] As an example, the negative electrode current collector can be a metal foil or a composite current collector. For example, as a metal foil, it can be aluminum with a silver-plated surface, stainless steel with a silver-plated surface, copper, aluminum, carbon electrode, carbon, nickel, or titanium, etc.

[0069] In some embodiments, the negative electrode current collector has two surfaces opposite each other in its own thickness direction, and the negative electrode active material is disposed on either or both of the two opposite surfaces of the negative electrode current collector.

[0070] As an example, the negative electrode active material may be a negative electrode active material known in the art for use in battery cells. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. Silicon-based materials may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. Tin-based materials may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials in battery cells may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0071] In some embodiments, the diaphragm is a separator membrane. This application does not impose any particular limitation on the type of separator membrane; any known porous separator membrane with good chemical and mechanical stability can be selected.

[0072] As an example, the main material of the separator can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramic. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation. The separator can be a separate component located between the positive and negative electrodes, or it can be attached to the surfaces of the positive and negative electrodes.

[0073] In some embodiments, the membrane is a solid electrolyte. The solid electrolyte is disposed between the positive and negative electrodes, serving both to transport ions and to isolate the positive and negative electrodes.

[0074] In some implementations, the electrode assembly is a wound structure. The positive and negative electrode sheets are wound into a wound structure.

[0075] In some embodiments, the battery cell may include a housing. The housing is used to encapsulate components such as electrode assemblies and electrolytes. The housing may be made of steel, aluminum, plastic (such as polypropylene), composite metal (such as copper-aluminum composite), or aluminum-plastic film, etc.

[0076] In some embodiments, the housing includes an end cap and a casing, the casing having an opening, and the end cap closing the opening to form a sealed space for accommodating substances such as electrode assemblies and electrolytes. The casing may have one or more openings. The end cap may also be provided one or more times.

[0077] In some embodiments, at least one electrode terminal is provided on the housing, and the electrode terminal is electrically connected to the tab of the electrode assembly. The electrode terminal can be directly connected to the tab or indirectly connected to the tab through a current collector. The electrode terminal can be provided on the end cap or on the housing.

[0078] In some implementations, an explosion-proof valve is provided on the housing. The explosion-proof valve is used to release the internal pressure of the battery cells.

[0079] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a pouch battery cell, or a battery cell of other shapes. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic batteries, such as hexagonal prismatic batteries. There are no particular limitations in the embodiments of this application.

[0080] During the winding process of electrode assemblies, a separator is typically used. The separator provides adhesion between the positive and negative electrode sheets on both sides, reducing the risk of relative folding or displacement of the separator and electrode sheets. However, in related technologies, the innermost ring of the wound electrode assembly consists of electrode sheets. During the winding process, these innermost electrode sheets are positioned opposite each other and adjacent to one another. Since the electrode sheets themselves lack adhesiveness, after the electrode assembly is manufactured, the innermost electrode sheets will separate, forming an opening. When the innermost ring of the electrode assembly has an opening, problems such as separator folding or displacement relative to the electrode sheets can easily occur during the unwinding of the winding needle, severely affecting the reliability of the individual battery cells.

[0081] In view of this, the battery cell provided in this application embodiment includes a casing, an electrode assembly, and an adhesive layer. The electrode assembly is housed within the casing, is wound, and includes a first electrode sheet. The innermost ring of the first electrode sheet includes a first straight portion and a second straight portion disposed opposite to each other. The adhesive layer bonds and connects the first straight portion and the second straight portion.

[0082] The battery cell provided in this application embodiment uses an adhesive layer to bond the first flat portion and the second flat portion of the first electrode sheet, thereby reducing the risk of an opening in the innermost ring of the electrode assembly caused by the separation of the first flat portion and the second flat portion of the innermost first electrode sheet. This reduces the risk of the separator folding or shifting relative to the electrode sheet, which is beneficial to improving the reliability of the battery cell.

[0083] The technical solutions described in the embodiments of this application are applicable to battery cells, battery devices including battery cells, and electrical devices using battery devices.

[0084] The battery device disclosed in this application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using the battery device disclosed in this application.

[0085] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric bicycles, electric motorcycles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0086] For ease of explanation, the following embodiments will be described using a vehicle 1 as an example of an electrical device according to an embodiment of this application.

[0087] Please refer to Figure 1 , Figure 1This is a schematic diagram of the structure of a vehicle 1 provided in an embodiment of this application. Vehicle 1 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 10 is installed inside vehicle 1, and the battery device 10 can be located at the bottom, front, or rear of vehicle 1. The battery device 10 can be used to power vehicle 1; for example, the battery device 10 can serve as the operating power source for vehicle 1's electrical system, such as meeting the power requirements for starting, navigation, and operation of vehicle 1.

[0088] The vehicle 1 may also include a controller 1b and a motor 1a. The controller 1b is used to control the battery device 10 to supply power to the motor 1a, for example, for the power needs of the vehicle 1 during starting, navigation and driving.

[0089] In some embodiments of this application, the battery device 10 can not only serve as the operating power source for the vehicle 1, but also as the driving power source for the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0090] Please refer to Figure 2 and Figure 3 , Figure 2 This is a schematic diagram of the structure of the battery device 10 provided in the embodiments of this application. Figure 3 This is an exploded view of the battery cell 30 provided in an embodiment of this application. The battery device 10 includes a housing 11 and a battery cell 30, with the battery cell 30 housed within the housing 11. The housing 11 provides a space for the battery cell 30, and the housing 11 can have various structures. In some embodiments, the housing 11 may include a first sub-housing 111 and a second sub-housing 112, which overlap each other, and together define a space for accommodating the battery cell 30. The second sub-box 112 can be a hollow structure with one end open, and the first sub-box 111 can be a plate-like structure. The first sub-box 111 covers the opening side of the second sub-box 112 so that the first sub-box 111 and the second sub-box 112 together define the accommodating space. Alternatively, the first sub-box 111 and the second sub-box 112 can both be hollow structures with one side open, and the opening side of the first sub-box 111 covers the opening side of the second sub-box 112.

[0091] In the battery device 10, there can be multiple battery cells 30, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 30 are connected in both series and parallel configurations. Multiple battery cells 30 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 30 is housed within the housing 11. Alternatively, the battery device 10 can also consist of multiple battery cells 30 first connected in series, parallel, or in a mixed manner to form a battery cell assembly 20, and then the multiple battery cell assemblies 20 are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 11. The battery device 10 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 30.

[0092] Among them, the battery cell 30 can be a secondary battery or a primary battery; the battery cell 30 can also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but is not limited to these.

[0093] Please refer to Figure 4 , Figure 4 This is a schematic diagram of the exploded structure of a battery cell 30 provided in an embodiment of this application. Figure 4 As shown, the battery cell 30 includes a housing 31, an electrode assembly 32, and electrode terminals 33. The housing 31 includes a casing 311 and an end cap 312. The casing 311 has an opening, and the end cap 312 closes the opening to isolate the internal environment of the battery cell 30 from the external environment.

[0094] The housing 311 is a component used to cooperate with the end cap 312 to form the internal environment of the battery cell 30, wherein the formed internal environment can accommodate the electrode assembly 32, electrolyte, and other components. The housing 311 and the end cap 312 can be independent components. The housing 311 can have various shapes and sizes. Specifically, the shape of the housing 311 can be determined according to the specific shape and size of the electrode assembly 32. The housing 311 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, and plastic.

[0095] End cap 312 refers to a component that covers the opening of housing 311 to isolate the internal environment of battery cell 30 from the external environment. The shape of end cap 312 can be adapted to the shape of housing 311 to fit it. Optionally, end cap 312 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 312 is not easily deformed under pressure and impact, giving battery cell 30 higher structural strength and improved reliability. Functional components such as electrode terminals 33 can be provided on end cap 312. Electrode terminals 33 can be used for electrical connection with electrode assembly 32 to output or input electrical energy to battery cell 30. The material of end cap 312 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose special limitations on this. In some embodiments, an insulating structure may be provided on the inner side of the end cap 312. The insulating structure can be used to isolate the electrical connection components within the housing 311 from the end cap 312 to reduce the risk of short circuits. For example, the insulating structure may be made of plastic, rubber, etc.

[0096] Electrode assembly 32 is the component in the battery cell 30 where electrochemical reactions occur. The housing 311 may contain one or more electrode assemblies 32. The electrode assembly 32 is mainly formed by winding or stacking positive and negative electrode plates, and typically a separator is provided between the positive and negative electrode plates to separate them and prevent internal short circuits. The portions of the positive and negative electrode plates containing active material constitute the electrode body 321 of the electrode assembly 32, while the portions of the positive and negative electrode plates without active material each constitute a tab 322. The positive and negative tabs may be located together at one end of the electrode body 321 or separately at both ends of the electrode body 321. During the charging and discharging process of the battery cell 30, the positive and negative active materials react with the electrolyte, and the tabs 322 connect to the electrode terminals 33 to form a current loop.

[0097] Firstly, such as Figure 4 and Figure 5 As shown, the battery cell 30 provided in this embodiment includes a housing 31, an electrode assembly 32, and an adhesive layer 50. The electrode assembly 32 is housed within the housing 31 and is in a wound shape, including a first electrode 40. The innermost ring of the first electrode 40 includes a first straight portion 41 and a second straight portion 42 disposed opposite to each other. The adhesive layer 50 bonds and connects the first straight portion 41 and the second straight portion 42.

[0098] The electrode assembly 32 includes a positive electrode plate, a negative electrode plate, and a separator. The separator is disposed between the positive electrode plate and the negative electrode plate to provide a certain degree of insulation between them. The electrode assembly 32 is wound in a spiral shape, with the positive electrode plate, the negative electrode plate, and the separator wound together.

[0099] The first electrode 40 can be a positive electrode or a negative electrode, and the first electrode 40 can be the electrode of the electrode assembly 32 wound around the innermost circle.

[0100] In some winding methods, the first electrode 40 is cut together with the diaphragm, and the diaphragm is only provided on one side of the first electrode 40. Therefore, after the first electrode 40 is wound, there is no diaphragm inside the innermost ring of the first electrode 40. When the electrode assembly 32 is wound into a polygonal prism shape, the innermost ring of the first electrode 40 has a first straight portion 41 and a second straight portion 42. There is no diaphragm between the first straight portion 41 and the second straight portion 42, and the first straight portion 41 and the second straight portion 42 can easily separate from each other, that is, the innermost ring of the electrode assembly 32 forms an opening.

[0101] During the winding process of electrode assembly 32, the presence of an opening can cause the diaphragm to fold or shift relative to the first electrode 40 or other electrodes, potentially leading to a short circuit between the positive and negative electrodes inside electrode assembly 32. Furthermore, the opening makes it difficult to control the tension of the winding on the electrodes and diaphragm, thus increasing the risk of uneven winding of electrode assembly 32. Additionally, during the high-speed rotation of the winding needle during the winding process, an opening in the innermost ring of electrode assembly 32 can cause the tab 322 to fold or crack.

[0102] By setting an adhesive layer 50 to bond the first straight portion 41 and the second straight portion 42, the first straight portion 41 and the second straight portion 42 of the innermost first electrode 40 are fixed relative to each other, reducing the risk of an opening in the innermost ring of the electrode assembly 32. This helps to reduce the risk of the diaphragm folding or shifting relative to the electrode, thereby reducing the risk of a short circuit inside the electrode assembly 32.

[0103] Optionally, an adhesive layer 50 may be applied to the first straight portion 41 or the second straight portion 42 before winding, or the adhesive layer 50 may be applied between the first straight portion 41 and the second straight portion 42 after winding.

[0104] In the embodiment where adhesive layer 50 is applied to the positions of the first straight portion 41 and the second straight portion 42 before winding, the first straight portion 41 and the second straight portion 42 adhere to each other during the winding process, especially during the winding of the innermost ring. This facilitates control of the tension of the winding needle on the electrode sheet and the diaphragm, and helps improve winding uniformity. Furthermore, the mutual adhesion of the first straight portion 41 and the second straight portion 42 on the innermost ring helps reduce the risk of the tab 322 folding or cracking during the high-speed rotation of the winding needle.

[0105] The adhesive layer 50 may be laid flat between the first straight portion 41 and the second straight portion 42, or the adhesive layer 50 may be in the form of a grid, stripes or other shapes.

[0106] Optionally, an adhesive layer 50 may be provided between all the opposing portions of the first straight portion 41 and the second straight portion 42, or an adhesive layer 50 may be provided between a portion of the opposing portions of the first straight portion 41 and the second straight portion 42.

[0107] The battery cell 30 provided in this application embodiment has an adhesive layer 50 that bonds the first straight portion 41 and the second straight portion 42 of the first electrode 40. This reduces the risk of an opening in the innermost ring of the electrode assembly 32 caused by the separation of the first straight portion 41 and the second straight portion 42 of the innermost first electrode 40. This also reduces the risk of the separator folding or shifting relative to the electrode, thereby reducing the risk of internal short circuits in the battery cell 30 caused by contact between the positive and negative electrodes. This improves the reliability of the battery cell 30.

[0108] In some embodiments, the surface area of ​​the first straight portion 41 and the second straight portion 42 facing each other is S, and the surface area of ​​the first straight portion 41 connected to the adhesive layer 50 is S1, where 50% ≤ S1 / S ≤ 100%.

[0109] Optionally, S1 / S can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%, etc.

[0110] It is understandable that the larger the value of S1 / S, the more beneficial it is to increase the bonding area of ​​the first straight portion 41 and the second straight portion 42, thereby improving the bonding strength of the first straight portion 41 and the second straight portion 42 and reducing the risk of cracking of the first straight portion 41 and the second straight portion 42.

[0111] Therefore, after systematic analysis and long-term practice, the inventors discovered that by setting 50%≤S1 / S≤100%, it is beneficial to improve the bonding strength of the first straight part 41 and the second straight part 42 and reduce the risk of cracking of the first straight part 41 and the second straight part 42.

[0112] In some embodiments, 70% ≤ S1 / S ≤ 90%.

[0113] Optionally, S1 / S can be 570%, 75%, 80%, 85%, or 90%, etc.

[0114] Understandably, the smaller the S1 / S ratio, the better it is at reducing the risk of adhesive layer 50 overflowing to the end of electrode assembly 32.

[0115] Therefore, after further systematic analysis and long-term practice, the inventors discovered that by setting 70%≤S1 / S≤90%, it is beneficial to further improve the bonding strength of the first straight portion 41 and the second straight portion 42, reduce the risk of cracking of the first straight portion 41 and the second straight portion 42, and reduce the risk of the adhesive layer 50 overflowing to the end of the electrode assembly 32.

[0116] In some embodiments, such as Figure 5 As shown, the minimum thickness e of the adhesive layer 50 satisfies: 10μm≤e≤200μm.

[0117] Alternatively, e can be 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 1 10μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm or 200μm, etc.

[0118] Understandably, a larger value for e generally improves the bonding strength between the first straight portion 41 and the second straight portion 42, reducing the risk of cracking. Conversely, a smaller value for e generally reduces the risk of the adhesive layer 50 overflowing to the end of the electrode assembly 32.

[0119] Therefore, after systematic analysis and long-term practice, the inventors found that by setting 10μm≤e≤200μm, it is beneficial to improve the bonding strength of the first straight portion 41 and the second straight portion 42, reduce the risk of cracking of the first straight portion 41 and the second straight portion 42, and also reduce the risk of the adhesive layer 50 overflowing to the end of the electrode assembly 32.

[0120] In some embodiments, 20μm≤e≤50μm.

[0121] Optionally, e can be 20μm, 25μm, 30μm, 35μm, 40μm, 45μm or 50μm, etc.

[0122] After further systematic analysis and long-term practice, the inventors discovered that by setting 20μm≤e≤50μm, it is beneficial to further improve the bonding strength of the first straight portion 41 and the second straight portion 42, reduce the risk of cracking of the first straight portion 41 and the second straight portion 42, and also to further reduce the risk of the adhesive layer 50 overflowing to the end of the electrode assembly 32.

[0123] In some embodiments, the melting point T of the adhesive layer 50 is ≥170°C.

[0124] During the cyclic operation, the battery cell 30 generates heat, causing the internal temperature of the battery cell 30 to rise. Under normal operating conditions, the maximum temperature of the battery cell 30 is below 170°C. By setting the melting point T of the adhesive layer 50 to be ≥170°C, it is beneficial to reduce the risk of the adhesive layer 50 softening or melting during the normal operation of the battery cell 30, which is beneficial to improving the structural stability of the adhesive layer 50, and thus beneficial to improving the reliability of the bonding connection between the first flat part 41 and the second flat part 42.

[0125] In some embodiments, such as Figure 4 , Figure 5 and Figure 6 As shown, the electrode assembly 32 includes an electrode body 321 and a tab 322, with the tab 322 extending from the end of the electrode body 321 along the first direction X. Along the first direction X, the shortest distance d from the edge of the adhesive layer 50 to the edge of the first straight portion 41 satisfies: 2mm ≤ d ≤ 10mm.

[0126] Thus, the edge of the adhesive layer 50 along the first direction X is spaced apart from the edge of the first straight portion 41 along the first direction X.

[0127] Optionally, d can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm or 10mm, etc.

[0128] It is understandable that the larger the value of d is to a certain extent, the more beneficial it is to reduce the risk of the adhesive layer 50 overflowing to the end of the electrode assembly 32 along the first direction X, while the smaller the value of d is to a certain extent, the more beneficial it is to improve the bonding strength of the first flat portion 41 and the second flat portion 42.

[0129] Therefore, after systematic analysis and long-term practice, the inventors discovered that by setting 2mm≤d≤10mm, it is beneficial to improve the bonding strength of the first straight portion 41 and the second straight portion 42, thereby increasing the risk of the first straight portion 41 and the second straight portion 42 splitting apart, and also to reduce the risk of the adhesive layer 50 overflowing between the first straight portion 41 and the second straight portion 42.

[0130] In some embodiments, such as Figure 5 and Figure 6 As shown, the first straight portion 41 includes alternating adhesive areas 41a and non-adhesive areas 41b, and the adhesive layer 50 is bonded to the adhesive area 41a of the first straight portion 41.

[0131] The adhesive area 41a and the non-adhesive area 41b are alternately arranged, which allows for the provision of multiple non-adhesive areas 41b. These multiple non-adhesive areas 41b can be arranged in an array or as multiple spaced strips. Of course, the adhesive area 41a and the non-adhesive area 41b can also be distributed in other ways. Correspondingly, the adhesive layer 50 can be arranged in a mesh or strip pattern between the first straight portion 41 and the second straight portion 42, resulting in larger pores between the first straight portion 41 and the second straight portion 42, facilitating the containment of more electrolyte.

[0132] Thus, the adhesive layer 50 is distributed in a large area between the first straight portion 41 and the second straight portion 42, which is beneficial to improving the bonding strength of the first straight portion 41 and the second straight portion 42. It can also utilize the gaps between the non-adhesive areas 41b to accommodate more electrolyte, and is beneficial to improving the wettability of the electrolyte to the electrode assembly 32, thereby improving the dynamic performance of the battery cell 30.

[0133] In some embodiments, the bonding area 41a is distributed in a mesh or strip pattern.

[0134] If the bonding area 41a is distributed in a mesh or strip pattern, then the adhesive layer 50 between the first straight portion 41 and the second straight portion 42 is also distributed in a mesh or strip pattern. This is beneficial to improving the wettability of the electrolyte to the electrode assembly 32, while also facilitating the forming process of the adhesive layer 50 on the first electrode sheet 40, which helps to simplify the process difficulty of the battery cell 30.

[0135] In some embodiments, the adhesive layer 50 is made of polypropylene.

[0136] Polypropylene has a high melting point and good thermal conductivity. By including polypropylene in the adhesive layer 50, the structural stability of the adhesive layer 50 can be improved, and the heat can be transferred away from the battery cell 30 in a timely manner during operation.

[0137] Secondly, the battery device 10 provided in the embodiments of this application includes the battery cell 30 provided in any of the above embodiments.

[0138] The battery device 10 provided in this application embodiment has the same technical effect as the battery cell 30 provided in any of the above embodiments, and will not be described again here.

[0139] Thirdly, the electrical device provided in the embodiments of this application includes the battery device 10 provided in the above embodiments, and the battery device 10 is used to provide electrical energy.

[0140] The electrical device provided in this application embodiment has the same technical effect as the battery device 10 provided in this application embodiment, and will not be described again here.

[0141] In some embodiments, such as Figures 4 to 6 As shown, the battery cell 30 provided in this embodiment includes a housing 31, an electrode assembly 32, and an adhesive layer 50. The electrode assembly 32 is housed within the housing 31 and is wound in shape. It includes a first electrode 40, the innermost ring of which includes a first straight portion 41 and a second straight portion 42 disposed opposite to each other. The adhesive layer 50 bonds the first straight portion 41 and the second straight portion 42 together. The surface area of ​​the first straight portion 41 and the second straight portion 42 opposite to each other is S, and the surface area of ​​the portion where the first straight portion 41 and the adhesive layer 50 are connected is S1, where 50% ≤ S1 / S ≤ 100%. The minimum thickness e of the adhesive layer 50 satisfies: 10μm ≤ e ≤ 200μm. The melting point T of the adhesive layer 50 is ≥ 170℃. The electrode assembly 32 includes an electrode body 321 and a tab 322, the tab 322 being led out from the end of the electrode body 321 along a first direction X. Along the first direction X, the shortest distance d from the edge of the adhesive layer 50 to the edge of the first straight portion 41 satisfies: 2mm ≤ d ≤ 10mm. The first straight portion 41 includes alternately arranged adhesive areas 41a and non-adhesive areas 41b, and the adhesive layer 50 is bonded to the adhesive areas 41a of the first straight portion 41. The adhesive areas 41a are distributed in a mesh or strip pattern, and the material of the adhesive layer 50 includes polypropylene.

[0142] The battery cell 30 provided in this application embodiment has an adhesive layer 50 that bonds the first straight portion 41 and the second straight portion 42 of the first electrode 40. This reduces the risk of an opening in the innermost ring of the electrode assembly 32 caused by the separation of the first straight portion 41 and the second straight portion 42 of the innermost first electrode 40. This also reduces the risk of the separator folding or shifting relative to the electrode, thereby reducing the risk of internal short circuits in the battery cell 30 caused by contact between the positive and negative electrodes. This improves the reliability of the battery cell 30.

[0143] Although this application has been described with reference to preferred embodiments, various modifications can be made thereto and components can be replaced with equivalents without departing from the scope of this application. In particular, the technical features mentioned in the various embodiments can be combined in any manner, provided there is no structural conflict. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, include: shell; An electrode assembly is housed within the housing. The electrode assembly is wound and includes a first electrode plate. The innermost ring of the first electrode plate includes a first straight portion and a second straight portion disposed opposite to each other. An adhesive layer is used to bond the first straight portion and the second straight portion together.

2. The battery cell according to claim 1, characterized in that, The surface area of ​​the first straight portion opposite to the second straight portion is S, and the surface area of ​​the first straight portion connected to the adhesive layer is S1, where 50% ≤ S1 / S ≤ 100%.

3. The battery cell according to claim 2, characterized in that, 70% ≤ S1 / S ≤ 90%.

4. The battery cell according to claim 1, characterized in that, The minimum thickness e of the adhesive layer satisfies: 10μm≤e≤200μm.

5. The battery cell according to claim 4, characterized in that, 20μm≤e≤50μm.

6. The battery cell according to claim 1, characterized in that, The melting point of the adhesive layer is T≥170℃.

7. The battery cell according to claim 1, characterized in that, The electrode assembly includes an electrode body and a tab, the tab being extended from the end of the electrode body along a first direction; Along the first direction, the shortest distance d from the edge of the adhesive layer to the edge of the first straight portion satisfies: 2mm≤d≤10mm.

8. The battery cell according to claim 1, characterized in that, The first straight portion includes alternating adhesive and non-adhesive areas, and the adhesive layer is bonded to the adhesive area of ​​the first straight portion.

9. The battery cell according to claim 8, characterized in that, The bonding area is distributed in a mesh or strip pattern.

10. The battery cell according to any one of claims 1 to 9, characterized in that, The adhesive layer is made of polypropylene.

11. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1 to 10.

12. An electrical appliance, characterized in that, Includes the battery device as described in claim 11, the battery device being used to provide electrical energy.

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