Battery cell, battery pack, and electric device

Abstract

Disclosed in embodiments of the present application are a battery cell, a battery pack, and an electric device. The battery cell has a first direction, and comprises: a casing; an electrode assembly, disposed in the casing; an end cap, disposed at one end of the casing and connected to the casing; and a current collector member, comprising a first current collector portion and a second current collector portion which are connected to each other, wherein the first current collector portion is disposed between the end cap and the electrode assembly and is electrically connected to the electrode assembly, the second current collector portion extends away from the end cap in the first direction, and the second current collector portion is disposed between the electrode assembly and the casing and is electrically connected to the casing. The present disclosure improves the spatial utilization of the electrode assembly in the casing, thereby increasing the energy density of the battery cell.

Description

Single battery, battery pack and electric device

[0001] Cross-reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202422287767.9, filed on September 18, 2024, and entitled “Single battery and battery pack”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of batteries, and in particular to a single battery, a battery pack and an electric device. BACKGROUND

[0004] With the rapid development of mobile phones, notebook computers, electric vehicles, electric tools and the like, batteries with high capacity, high cycle life and high safety performance have been widely applied and developed, and the demand for batteries with better performance such as greater capacity, greater durability and greater safety is very urgent. As one of the core performances of batteries, energy density, therefore, how to improve the energy density of the battery becomes a problem to be solved. SUMMARY

[0005] Embodiments of the present application provide a single battery, a battery pack and an electric device to improve the energy density of the single battery.

[0006] To solve the above technical problems, embodiments of the present application disclose the following technical solutions:

[0007] In one aspect, a single battery is provided, having a first direction, comprising:

[0008] a housing;

[0009] an electrode assembly disposed in the housing;

[0010] an end cover disposed at one end of the housing and connected with the housing; and

[0011] a current collecting member comprising a first current collecting part and a second current collecting part connected with each other, the first current collecting part being disposed between the end cover and the electrode assembly and electrically connected with the electrode assembly, the second current collecting part extending in the first direction away from the end cover, the second current collecting part being disposed between the electrode assembly and the housing and electrically connected with the housing.

[0012] In addition to one or more features disclosed above, or as an alternative, the thickness of the second current collecting part is L1 mm, the thickness of the housing is L2 mm, and 1≤L1 / L2≤1.5 is satisfied.

[0013] In addition to one or more of the above disclosed features, or alternatively, the thickness L1 of the second current collector satisfies 0.1mm≤L1≤1.5mm.

[0014] In addition to one or more of the above disclosed features, or alternatively, the thickness L2 of the housing satisfies 0.1mm≤L2≤1mm.

[0015] In addition to one or more of the above disclosed features, or alternatively, the thickness L3 of the first current collector satisfies 0.05mm≤L3≤1mm.

[0016] In addition to one or more of the above disclosed features, or alternatively, the maximum outer dimension D1 of the first current collector and the maximum outer dimension D2 of the electrode assembly satisfy 1.001≤D1 / D2≤1.1.

[0017] In addition to one or more of the above disclosed features, or alternatively, the maximum dimension H1 of the electrode assembly in the first direction and the maximum dimension H2 of the second current collector in the first direction satisfy 0.01≤H2 / H1≤1.

[0018] In addition to one or more of the above disclosed features, or alternatively, the second current collector has a contact surface, the contact surface has a connecting area, the second current collector is electrically connected with the housing through the connecting area.

[0019] The maximum area of the connecting area is S1mm 2 The maximum area of the contact surface is S2mm 2 0.3≤S1 / S2≤1.

[0020] In addition to one or more of the above disclosed features, or alternatively, the expansion adhesive layer is provided between the electrode assembly and the second current collector.

[0021] In addition to one or more of the above disclosed features, or alternatively, the thickness L4 of the expansion adhesive layer satisfies 0.01mm≤L4≤0.5mm.

[0022] In addition to one or more of the above disclosed features, or alternatively, the expansion adhesive layer is an insulating expansion adhesive.

[0023] In addition to one or more of the above disclosed features, or alternatively, the first current collector is electrically connected with the positive or negative tab of the electrode assembly.

[0024] In addition to one or more of the above disclosed features, or alternatively, the shell is cylindrical, and the second current collecting part is also cylindrical; the second current collecting part is sleeved on the outer periphery of the electrode assembly and the inner periphery of the shell.

[0025] In addition to one or more of the above disclosed features, or alternatively, the first current collecting part is arranged at one end of the second current collecting part close to the end cover.

[0026] In addition to one or more of the above disclosed features, or alternatively, the first current collecting part is circular.

[0027] In addition to one or more of the above disclosed features, or alternatively, the first current collecting part is a hollow annular ring.

[0028] In addition to one or more of the above disclosed features, or alternatively, the first current collecting part is integrally formed with the second current collecting part.

[0029] In another aspect, a battery pack is further disclosed, in addition to one or more of the above disclosed features, or alternatively, the battery pack comprises a box body; and the monomer battery as claimed in any one of the above is arranged in the box body.

[0030] In another aspect, a battery pack is further disclosed, in addition to one or more of the above disclosed features, or alternatively, the battery pack comprises a box body; and the monomer battery as claimed in any one of the above is arranged in the box body.

[0031] In another aspect, a battery pack is further disclosed, in addition to one or more of the above disclosed features, or alternatively, the battery pack comprises a box body; and the monomer battery as claimed in any one of the above is arranged in the box body.

[0032] One of the above technical solutions has the following advantages or beneficial effects: the present application sets the first current collecting part of the current collecting member between the end cover and the electrode assembly, and sets the second current collecting part between the electrode assembly and the shell, so as to reduce the occupation of the space in the first direction inside the shell by the current collecting member, so that more electrode assemblies can be accommodated in the shell, thereby improving the space utilization of the electrode assemblies in the shell, and improving the energy density of the monomer battery; at the same time, the first current collecting part is electrically connected with the electrode assembly, and the second current collecting part is electrically connected with the shell, so that the monomer battery forms an electric current path of electrode assembly-first current collecting part-second current collecting part-shell, thereby making the electric current path not conductive to the end cover when the monomer battery is normally working, and thereby making the resistance value of the structural member when the monomer battery is working not include the end cover, effectively reducing the internal resistance of the monomer battery, reducing the heat generation when the monomer battery is normally working, and improving the performance of the monomer battery. BRIEF DESCRIPTION OF DRAWINGS

[0033] The technical solutions and other beneficial effects of the present application will become apparent from the following detailed description of specific embodiments of the present application, taken in conjunction with the accompanying drawings.

[0034] Fig. 1 is an exploded structural view of a single battery according to an embodiment of the present application;

[0035] Fig. 2 is a partial cross-sectional view of a single battery according to an embodiment of the present application;

[0036] Fig. 3 is a cross-sectional view of an electrode assembly and a current collecting member according to an embodiment of the present application;

[0037] Fig. 4 is a partial enlarged view of A in Fig. 3.

[0038] Reference Signs: 100, single battery; 110, case; 120, electrode assembly; 130, end cap; 140, current collecting member; 141, first current collecting part; 142, second current collecting part; 1421, contact surface; 150, swelling adhesive layer. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and beneficial effects of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described in the present specification are only for the purpose of explaining the present disclosure and are not intended to limit the present disclosure.

[0040] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present disclosure. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features limited by "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0041] In the description of the disclosure, it should be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, it can be direct connection, or indirect connection through intermediate medium, it can be internal communication of two elements or interaction relationship of two elements. For those skilled in the art, the specific meaning of the above terms in the disclosure can be understood according to the specific circumstances.

[0042] In the present disclosure, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "under" and "under" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0043] The existing large cylindrical battery has been widely concerned because of its superior performance of low internal resistance and high energy density. At present, after the current collecting disc and the electrode assembly in the large cylindrical battery are electrically connected, the current collecting disc can be lap welded with the shell or welded with the end cover. When the current collecting disc is lap welded with the shell, the lap structure on the current collecting disc occupies a large height space, which affects the energy density of the battery, and the lap structure is prone to poor contact with the shell, affecting the welding effect. When the current collecting disc is welded with the end cover, the two are mainly connected through the way of penetration welding, and the penetration welding requires very small gap between the end cover and the current collecting disc, and has high tolerance requirement for the height of the electrode assembly and the structural member, and the manufacturing process is difficult.

[0044] In order to solve the above problems, in the embodiments of the present application, with reference to FIGS. 1-4, the present application provides a single battery 100, which has a first direction Z. For example, the first direction Z is the height direction of the single battery 100 in the present application.

[0045] The single battery 100 can be a secondary battery, which refers to a battery that can be activated by charging after discharging. For example, the single battery 100 can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery or a nickel cadmium battery, but is not limited thereto.

[0046] The single battery 100 can be a cylindrical battery, a prismatic battery, a soft package battery or a battery of other shapes.

[0047] Specifically, the single battery 100 can include a shell 110, an electrode assembly 120, an end cover 130, and a current collecting member 140.

[0048] Specifically, the electrode assembly 120 is arranged in the shell 110; the end cover 130 is arranged at one end of the shell 110, and the end cover 130 and the shell 110 are connected; and the current collecting member 140 is arranged in the shell 110 and between the end cover 130 and the electrode assembly 120.

[0049] The shell 110 can be made of a metal material, but is not limited thereto. For example, the shell 110 can be made of an aluminum profile, but is not limited thereto.

[0050] The end cover 130 can be integrally formed with the shell 110, that is, the end cover 130 and the shell 110 are in an integrated structure; or the end cover 130 can be separately formed with the shell 110 and then fixedly connected, for example, the end cover 130 is fixedly connected to one end of the shell 110 in the first direction Z by welding or other processes. In the present disclosure, no specific limitation is made, and the actual situation can be specifically set. For example, in the present disclosure, the end cover 130 is separately arranged with the shell 110, and the end cover 130 and the shell 110 are fixedly connected by welding.

[0051] The single battery 100 further includes electrolyte, a pole, and other functional components. The electrolyte can be a conventional electrolyte or a special electrolyte with additives. The electrolyte is used to soak the electrode assembly 120. The electrode assembly 120 is a component where an electrochemical reaction occurs in the single battery 100, and can be one or more. The electrode assembly 120 is mainly formed by winding or stacking a positive plate, a separator, and a negative plate. The positive plate and the negative plate have a part of active material to form an electrode body, and a part without active material to form a tab. In the charging and discharging process of the single battery 100, the positive active material and the negative active material react with the electrolyte, and the tab is electrically connected to the pole to form a current loop, so that the single battery 100 can be normally used.

[0052] The current collecting member 140 can be a positive current collecting disc or a negative current collecting disc, and no specific limitation is made in the present disclosure.

[0053] Specifically, the current collecting member 140 comprises a first current collecting part 141 and a second current collecting part 142 connected with each other. The first current collecting part 141 is arranged between the end cover 130 and the electrode assembly 120, and the first current collecting part 141 is electrically connected with the electrode assembly 120. The first current collecting part 141 is insulated from the end cover 130. The second current collecting part 142 extends away from the end cover 130 in the first direction Z. The second current collecting part 142 is arranged between the electrode assembly 120 and the shell 110, and the second current collecting part 142 is electrically connected with the shell 110. The second current collecting part 142 is insulated from the electrode assembly 120, so as to form a current path of the electrode assembly 120-the first current collecting part 141-the second current collecting part 142-the shell 110.

[0054] The first current collecting part 141 can be in a disc shape, or the central region of the first current collecting part 141 can be hollow, so that the first current collecting part 141 is in a ring shape. The present disclosure does not make specific limitations, and the actual situation can be specifically selected.

[0055] The first current collecting part 141 can be integrally formed with the second current collecting part 142, that is, the first current collecting part 141 and the second current collecting part 142 are in an integrated structure. The first current collecting part 141 can also be separately formed with the second current collecting part 142 and then fixedly connected, for example, the first current collecting part 141 is fixedly connected with the second current collecting part 142 by welding or other processes. The present disclosure does not make specific limitations, and the actual situation can be specifically set. For example, in the present disclosure, the first current collecting part 141 and the second current collecting part 142 can be integrally formed by using a die casting mold, so as to improve the forming efficiency of the current collecting member 140, and further improve the overall assembly efficiency of the single battery 100.

[0056] The material of the first current collecting part 141 and the second current collecting part 142 can be various, and the material of the first current collecting part 141 and the second current collecting part 142 can be the same or different. For example, the material of the first current collecting part 141 and the second current collecting part 142 can be any one of copper, iron, aluminum, steel, or aluminum alloy and other conductive materials, but is not limited thereto.

[0057] The connection mode between the first current collecting part 141 and the electrode assembly 120 can be various, for example, welding, abutting, or connecting through conductive glue, etc. The first current collecting part 141 is connected with one of the positive electrode tab or the negative electrode tab of the electrode assembly 120. Similarly, the connection mode between the second current collecting part 142 and the shell 110 can also be various, for example, welding, abutting, or connecting through conductive glue, etc.

[0058] The connection manners between different regions of the second current collecting part 142 and the shell 110 can be the same or different. In the present disclosure, the first current collecting part 141 is fixed between the electrode assembly 120 by laser welding, and the second current collecting part 142 is fixed between the shell 110 by laser welding.

[0059] The conductive coefficient of the second current collecting part 142 can be greater than, less than, or consistent with the conductive coefficient of the shell 110. In the present disclosure, no specific limitation is made, and the conductive coefficient of the second current collecting part 142 can be set according to the actual situation.

[0060] It can be understood that, by arranging the first current collecting part 141 of the current collecting member 140 between the end cover 130 and the electrode assembly 120 and arranging the second current collecting part 142 between the electrode assembly 120 and the shell 110, the present disclosure reduces the occupation of the space in the first direction Z inside the shell 110 by the current collecting member 140, so that more electrode assemblies 120 can be accommodated in the shell 110, thereby improving the space utilization of the electrode assemblies 120 in the shell 110 and improving the energy density of the single battery 100. At the same time, in the present disclosure, the first current collecting part 141 is electrically connected to the electrode assembly 120, and the second current collecting part 142 is electrically connected to the shell 110, so that the single battery 100 forms a current path of the electrode assembly 120-first current collecting part 141-second current collecting part 142-shell 110, thereby making the current path not conductive to the end cover 130 when the single battery 100 is normally working, and thereby making the resistance value of the structural member when the single battery 100 is working not include the end cover 130, effectively reducing the internal resistance of the single battery 100 and reducing the heat generation when the single battery 100 is normally working, thereby improving the performance of the single battery 100. At the same time, the current collecting member 140 in the present disclosure adopts the above connection arrangement, so that there is no requirement for the tolerance of the electrode assembly 120 and other structural members in the single battery 100, thereby reducing the production process difficulty of the single battery 100, improving the manufacturability of the single battery 100, and thereby improving the production efficiency of the single battery 100.

[0061] In an embodiment, the thickness of the second current collecting part 142 at different positions can be uniform or non-uniform. When the second current collecting part 142 is a structure with uniform thickness, the thickness ratio of the second current collecting part to the shell 110 is fixed. If it is not a structure with uniform thickness, the thickness ratio is a range value, rather than a single point data.

[0062] In the present disclosure, the thickness of the second current collecting part 142 at different positions is consistent, and even if it is not consistent, there is a small thickness difference based on the processing.

[0063] Specifically, the thickness of the second current collecting part 142 is L1 mm, and the thickness of the shell 110 is L2 mm, and the following condition is satisfied: 1≤L1 / L2≤1.5. Specifically, when the second current collecting part 142 is of a non-uniform thickness structure, the ratio of the thickness L1 mm of the second current collecting part 142 to the thickness L2 mm of the shell 110 can be controlled to be in the range of 1-1.1, 1.1-1.3, 1.2-1.4, or 1.3-1.5. When the second current collecting part 142 is of a uniform thickness structure, L1 / L2 can be 1, 1.05, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, or 1.5. It should be noted that the specific values of L1 / L2 are only exemplary, and any value of the ratio of the thickness of the second current collecting part 142 to the thickness of the shell 110 in the range of 1-1.5 is within the protection scope of the present disclosure.

[0064] The thickness L1 mm of the second current collecting part 142 can be obtained by measuring the distance between the two surfaces of the second current collecting part 142 of the current collecting member 140 arranged opposite to each other in the thickness direction and calculating the average value by using a measuring tool multiple times after the actual single battery 100 is disassembled. The measuring tool can be any one of a ruler, a vernier caliper, or other size measuring instruments, but is not limited thereto.

[0065] The thickness L2 mm of the shell 110 can be obtained by measuring the distance between the two surfaces of the side wall of the shell 110 arranged opposite to each other in the thickness direction and calculating the average value by using a measuring tool multiple times after the actual single battery 100 is disassembled. The measuring tool can be any one of a ruler, a vernier caliper, or other size measuring instruments, but is not limited thereto.

[0066] It can be understood that, by limiting the ratio of the thickness L1 mm of the second current collecting part 142 to the thickness L2 mm of the shell 110 to be in the range of 1-1.5, the thickness structure of the second current collecting part 142 is reasonably designed, so as to further reduce the occupation of the internal space of the shell 110 by the current collecting member 140, so that more electrode assemblies 120 can be accommodated in the shell 110, thereby improving the space utilization of the electrode assemblies 120 in the shell 110, and ultimately improving the energy density of the single battery 100.

[0067] In an embodiment, the thickness L1mm of the second current collecting part 142 also satisfies: 0.1mm≤L1≤1.5mm. Specifically, when the second current collecting part 142 is of a non-uniform thickness structure, the thickness L1mm of the second current collecting part 142 can be controlled in the range of 0.1mm-0.5mm, 0.3mm-0.8mm, 0.5mm-1mm or 1mm-1.5mm. When the second current collecting part 142 is of a uniform thickness structure, the thickness L1mm of the second current collecting part 142 can be 0.1mm, 0.3mm, 0.5mm, 0.7mm, 0.9mm, 1.1mm, 1.3mm or 1.5mm. It is worth noting that the specific values of L1mm are only exemplarily given, and any value within the range of 0.1mm-1.5mm is within the protection scope of the present disclosure.

[0068] The present disclosure further reasonably designs the thickness structure of the second current collecting part 142 by limiting the thickness L1mm of the second current collecting part 142 within the range of 0.1mm-1.5mm, so as to further reduce the occupation of the internal space of the shell 110 by the current collecting member 140, so that more electrode assemblies 120 can be accommodated in the shell 110, thereby improving the space utilization of the electrode assemblies 120 in the shell 110, and finally improving the energy density of the single battery 100.

[0069] In an embodiment, the thickness L2mm of the shell 110 also satisfies: 0.1mm≤L2≤1mm. That is, the thickness L2mm of the shell 110 can be controlled within the range of 0.1mm-1mm. For example, the thickness L2mm of the shell 110 can be one of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1mm, or a range formed by any two of them. The above specific values of L2mm are only exemplarily given, and any value within the range of 0.1mm-1mm is within the protection scope of the present disclosure. The present disclosure designs the thickness structure of the shell 110 by limiting the thickness L2mm of the shell 110 within the range of 0.1mm-1mm, so as to ensure that the shell 110 has a certain structural strength, thereby guaranteeing that the shell 110 has a good protection function, so as to improve the safety performance of the single battery 100.

[0070] In an embodiment, the thickness of the first current collecting part 141 is also designed in the present disclosure. Specifically, the thickness of the first current collecting part 141 is L3 mm, which satisfies: 0.05 mm≤L3≤1 mm. That is, the thickness L3 mm of the first current collecting part 141 can be controlled within the range of 0.05 mm to 1 mm. For example, the thickness L3 mm of the first current collecting part 141 can be one of 0.05 mm, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm, or a range formed by any two of them. The above specific values of L3 mm are only exemplarily given, and any value within the range of 0.05 mm to 1 mm is within the protection scope of the present disclosure. The present disclosure limits the thickness L3 mm of the first current collecting part 141 within the range of 0.05 mm to 1 mm, so as to reasonably design the thickness dimension of the first current collecting part 141, reduce the occupation of the first current collecting part 141 of the current collecting member 140 to the internal space of the shell 110, further accommodate more electrode assemblies 120 in the shell 110, thereby improving the space utilization of the electrode assemblies 120 in the shell 110, and finally improving the energy density of the single battery 100.

[0071] The thickness L3 mm of the first current collecting part 141 can be obtained by measuring the distance between the two surfaces of the first current collecting part 141 of the current collecting member 140 arranged in the thickness direction and calculating the average value multiple times after the actual single battery 100 is disassembled. The measuring tool can be any one of a ruler, a vernier caliper, or other size measuring instruments, but is not limited thereto.

[0072] Further, the thickness L3 mm of the first current collecting part 141 also satisfies: 0.1 mm≤L3≤0.5 mm. That is, the thickness L3 mm of the first current collecting part 141 can be controlled within the range of 0.1 mm to 0.5 mm. For example, the thickness L3 mm of the first current collecting part 141 can be one of 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, or 0.5 mm, or a range formed by any two of them. The above specific values of L3 mm are only exemplarily given, and any value within the range of 0.1 mm to 0.5 mm is within the protection scope of the present disclosure. The present disclosure limits the thickness L3 mm of the first current collecting part 141 within the range of 0.1 mm to 0.5 mm, so as to further reasonably design the thickness dimension of the first current collecting part 141, reduce the occupation of the first current collecting part 141 of the current collecting member 140 to the internal space of the shell 110, further accommodate more electrode assemblies 120 in the shell 110, thereby improving the space utilization of the electrode assemblies 120 in the shell 110, and finally improving the energy density of the single battery 100.

[0073] In an embodiment, the maximum outer contour dimension of the first current collecting part 141 is D1 mm, the maximum outer contour dimension of the electrode assembly 120 is D2 mm, and the following condition is satisfied: 1.001≤D1 / D2≤1.1. That is, the ratio of the maximum outer contour dimension D1 mm of the first current collecting part 141 to the maximum outer contour dimension D2 mm of the electrode assembly 120 can be controlled to be within the range of 1.001-1.1. For example, D1 / D2 can be one of 1.001, 1.005, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, or 1.1, or a range defined by any two of them. The above specific values of D1 / D2 are only exemplary, and any value within the range of 1.001-1.1 is within the protection scope of the present disclosure. The present disclosure limits the ratio of the maximum outer contour dimension D1 mm of the first current collecting part 141 to the maximum outer contour dimension D2 mm of the electrode assembly 120 to be within the range of 1.001-1.1, so as to reasonably design the structural size of the first current collecting part 141, to ensure that the first current collecting part 141 has sufficient contact area to connect with the electrode assembly 120, and in the case of better electrical conductivity, it can also ensure that the single battery 100 can fully utilize the current collecting member 140 for heat dissipation when working normally, thereby improving the heat dissipation performance of the single battery 100, and ultimately improving the safety performance of the single battery 100.

[0074] The maximum outer contour dimension D1 mm of the first current collecting part 141 can be obtained by measuring the outer contour dimensions of different positions of the first current collecting part 141 in the first direction Z and calculating the average value. For example, the maximum outer contour dimension D1 mm of the first current collecting part 141 can be obtained by measuring the outer contour dimensions of the two ends of the first current collecting part 141 in the first direction Z and the outer contour dimension of the middle region of the first current collecting part 141 in the first direction Z, and calculating the average value. The measuring tool can be any one of a ruler, a vernier caliper, or other size measuring tools, but is not limited thereto.

[0075] The maximum outer profile size D2mm of the electrode assembly 120 can be obtained by measuring the outer profile size of the electrode assembly 120 at different positions in the first direction Z by a measuring tool and calculating the average value after the actual single battery 100 is disassembled. For example, the maximum outer profile size D2mm of the electrode assembly 120 can be obtained by measuring the outer profile size of the electrode assembly 120 at two ends arranged oppositely in the first direction Z and the outer profile size of the electrode assembly 120 at the middle region in the first direction Z by a measuring tool and calculating the average value. The measuring tool can be any one of a ruler, a vernier caliper or other size measuring tools, but is not limited thereto.

[0076] Further, the maximum outer profile size of the first current collecting part 141 is D1mm, and the maximum outer profile size of the electrode assembly 120 is D2mm, which satisfy 1.005≤D1 / D2≤1.05. That is, the ratio of the maximum outer profile size D1mm of the first current collecting part 141 to the maximum outer profile size D2mm of the electrode assembly 120 can be controlled in the range of 1.005-1.05. For example, D1 / D2 can be one of 1.005, 1.01, 1.015, 1.02, 1.025, 1.03, 1.035, 1.04, 1.045 or 1.05 or a range formed by any two of them. The above specific values of D1 / D2 are only exemplarily given, and any value in the range of 1.005-1.05 is within the protection scope of the present disclosure. The present disclosure limits the ratio of the maximum outer profile size D1mm of the first current collecting part 141 to the maximum outer profile size D2mm of the electrode assembly 120 in the range of 1.005-1.05 to further reasonably design the structure size of the first current collecting part 141, to ensure that the first current collecting part 141 has sufficient contact area to connect with the electrode assembly 120, to ensure that the single battery 100 can fully utilize the current collecting member 140 to dissipate heat when working normally, to improve the heat dissipation performance of the single battery 100, and finally to improve the safety performance of the single battery 100.

[0077] In an embodiment, the maximum dimension of the electrode assembly 120 in the first direction Z is H1 mm, the maximum dimension of the second current collecting portion 142 in the first direction Z is H2 mm, and the following condition is satisfied: 0.01≤H2 / H1≤1. That is, the ratio of the maximum dimension H2 mm of the second current collecting portion 142 in the first direction Z to the maximum dimension H1 mm of the electrode assembly 120 in the first direction Z can be controlled to be within the range of 0.01 to 1. For example, H2 / H1 can be one of 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1, or a range formed by any two of them. The above specific values of H2 / H1 are only exemplary, and any value within the range of 0.01 to 1 is within the protection scope of the present disclosure. The present disclosure limits the ratio of the maximum dimension H2 mm of the second current collecting portion 142 in the first direction Z to the maximum dimension H1 mm of the electrode assembly 120 in the first direction Z to be within the range of 0.01 to 1, so as to reasonably design the structural size of the second current collecting portion 142, ensure that the second current collecting portion 142 has sufficient contact area to connect with the shell 110, and further ensure that the single battery 100 can fully utilize the current collecting member 140 to dissipate heat when the single battery 100 is working normally, thereby improving the heat dissipation performance of the single battery 100 and ultimately improving the safety performance of the single battery 100.

[0078] The maximum dimension H1 mm of the electrode assembly 120 in the first direction Z can be obtained by measuring the distance between the two oppositely arranged surfaces of the electrode assembly 120 in the first direction Z multiple times and calculating the average value after the actual single battery 100 is disassembled. The measuring tool can be any one of a ruler, a vernier caliper, or other size measuring instruments, but is not limited thereto.

[0079] The maximum dimension H2 mm of the second current collecting portion 142 in the first direction Z can be obtained by measuring the distance between the two oppositely arranged surfaces of the second current collecting portion 142 of the current collecting member 140 in the first direction Z multiple times and calculating the average value after the actual single battery 100 is disassembled. The measuring tool can be any one of a ruler, a vernier caliper, or other size measuring instruments, but is not limited thereto.

[0080] In an embodiment, the maximum dimension H1mm of the electrode assembly 120 in the first direction Z and the maximum dimension H2mm of the second current collecting portion 142 in the first direction Z also satisfy: 0.3≤H2 / H1≤0.9. That is, the ratio of the maximum dimension H2mm of the second current collecting portion 142 in the first direction Z and the maximum dimension H1mm of the electrode assembly 120 in the first direction Z can be controlled within the range of 0.3-0.9. For example, H2 / H1 can be one of 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, or 0.9, or a range consisting of any two of them. The above specific values of H2 / H1 are only exemplary, and any value within the range of 0.3-0.9 is within the protection scope of the present disclosure. The present disclosure limits the ratio of the maximum dimension H2mm of the second current collecting portion 142 in the first direction Z and the maximum dimension H1mm of the electrode assembly 120 in the first direction Z within the range of 0.3-0.9, to further reasonably design the structural size of the second current collecting portion 142, to ensure that the second current collecting portion 142 has sufficient contact area to connect with the shell 110, to enable better conduction, and also to ensure that the monomer battery 100 can fully utilize the current collecting member 140 for heat dissipation when the monomer battery 100 is working normally, to improve the heat dissipation performance of the monomer battery 100, and ultimately to improve the safety performance of the monomer battery 100.

[0081] In an embodiment, the second current collecting portion 142 has a contact surface 1421, and the contact surface 1421 has a connecting area 14211, and the second current collecting portion 142 is electrically connected with the shell 110 through the connecting area 14211.

[0082] In the present disclosure, the contact surface 1421 of the second current collecting portion 142 is an outer surface, and the connecting area 14211 of the contact surface 1421 can be directly connected with the shell 110, or welded, or connected with the shell 110 by using conductive glue. For example, in the present disclosure, the connecting area 14211 of the contact surface 1421 is welded with the shell 110, and the connecting area 14211 is a welding area.

[0083] Specifically, the maximum area of the connecting area 14211 is S1mm 2 , the maximum area of the contact surface 1421 is S2mm 2 , and 0.3≤S1 / S2≤1. That is, the maximum area S1mm 2 of the connecting area 14211 and the maximum area S2mm 2The ratio can be controlled within the range of 0.3 to 1. For example, S1 / S2 can be a range of one or any two of 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. The specific values ​​of S1 / S2 given above are merely illustrative, and any value within the range of 0.3 to 1 is within the protection scope of this disclosure.

[0084] This disclosure defines the maximum area S1mm of the connection region 14211. 2 The maximum area S2mm of the contact surface 1421 2 The ratio is in the range of 0.3 to 1, so as to further rationally design the structural dimensions of the second current collector 142, ensure that the second current collector 142 and the housing 110 are fully connected, and ensure that the current collector 140 can be fully utilized for heat dissipation when the single battery 100 is working normally, thereby improving the heat dissipation performance of the single battery 100 and ultimately improving the safety performance of the single battery 100.

[0085] Among them, the maximum area of ​​contact surface 1421 is S2mm. 2 The actual single cell 100 can be disassembled, and the second current collector 142 of the current collector component 140 can be flattened. The image area of ​​the contact surface 1421 of the second current collector 142 can be measured multiple times using a projection measurement device (such as a digital microscope or image measuring instrument) to obtain the maximum area S2mm of the contact surface 1421. 2 However, it is not limited to this.

[0086] The maximum area of ​​the connecting region 14211 is S1mm. 2 The actual single cell 100 can be disassembled, and the second current collector 142 of the current collector component 140 can be flattened. The image area of ​​the connection area 14211 of the contact surface 1421 of the second current collector 142 can be measured multiple times using a projection measurement device (such as a digital microscope or image measuring instrument) to obtain the maximum area S1mm of the connection area 14211. 2 However, it is not limited to this.

[0087] Furthermore, the maximum area of ​​the connecting region 14211 is S1mm. 2 The maximum area S2mm of the contact surface 1421 2 It also satisfies: 0.9 ≤ S1 / S2 ≤ 1. That is, the maximum area of ​​the connected region 14211 is S1 mm. 2 The maximum area S2mm of the contact surface 1421 2The ratio of S1 / S2 can be controlled within the range of 0.9-1. Exemplarily, S1 / S2 can be one of 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, 0.99, or 1, or a range consisting of any two of them. The above specific values of S1 / S2 are only exemplarily given, and any value within the range of 0.9-1 is within the protection scope of the present disclosure.

[0088] The present disclosure limits the maximum area S1mm 2 of the connecting area 14211 to be within the range of 0.9-1 of the maximum area S2mm 2 of the contact surface 1421, to further reasonably design the structural size of the second current collecting part 142, to ensure that the second current collecting part 142 is in sufficient contact with the shell 110, to ensure that the monomer battery 100 can fully utilize the current collecting member 140 for heat dissipation when working normally, to improve the heat dissipation performance of the monomer battery 100, and finally to improve the safety performance of the monomer battery 100.

[0089] Further, the shell 110 is in a cylindrical shape, and the second current collecting part 142 is also in a cylindrical shape. The second current collecting part 142 is sleeved on the outer periphery of the electrode assembly 120 and is sleeved on the inner periphery of the shell 110. The first current collecting part 141 is arranged at one end of the second current collecting part 142 close to the end cover 130.

[0090] In an embodiment, the monomer battery 100 further comprises an expansion adhesive layer 150, at least part of the expansion adhesive layer 150 being arranged between the electrode assembly 120 and the second current collecting part 142, to ensure that the second current collecting part 142 is in contact with the shell 110 after the expansion adhesive layer 150 expands, to realize electrical conduction between the two.

[0091] In the expansion adhesive layer 150, an insulating material can also be added, to ensure that the expansion adhesive layer 150 has an insulating function, to realize the insulating arrangement between the second current collecting part 142 and the electrode assembly 120, to avoid short circuit caused by the direct contact between the second current collecting part 142 and the electrode assembly 120. That is, the expansion adhesive layer 150 is an insulating expansion adhesive.

[0092] In an embodiment, the thickness of the expansion adhesive layer 150 is L4mm, and satisfies: 0.01mm≤L4≤0.5mm. That is, the thickness L4mm of the expansion adhesive layer 150 can be controlled within the range of 0.01mm to 0.5mm. For example, the thickness L4mm of the expansion adhesive layer 150 can be one of 0.01mm, 0.05mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm, or a range formed by any two of them. The above specific values of L4mm are only exemplary, and any value within the range of 0.01mm to 0.5mm is within the protection scope of the present disclosure. The present disclosure limits the thickness L4mm of the expansion adhesive layer 150 within the range of 0.01mm to 0.5mm, so as to reasonably design the structure size of the expansion adhesive layer 150, reduce the occupation of the internal space of the shell 110 by the expansion adhesive layer 150, further accommodate more electrode assemblies 120 in the shell 110, thereby improving the space utilization of the electrode assemblies 120 in the shell 110, and finally improving the energy density of the single battery 100.

[0093] The thickness L4mm of the expansion adhesive layer 150 can be obtained by measuring the distance between the two surfaces of the expansion adhesive layer 150 arranged in the thickness direction and calculating the average value multiple times after the actual single battery 100 is disassembled. The measuring tool can be any one of a ruler, a vernier caliper or other size measuring instruments, but is not limited thereto.

[0094] Further, the thickness L4mm of the expansion adhesive layer 150 also satisfies: 0.05mm≤L4≤0.3mm. That is, the thickness L4mm of the expansion adhesive layer 150 can be controlled within the range of 0.05mm to 0.3mm. For example, the thickness L4mm of the expansion adhesive layer 150 can be one of 0.05mm, 0.075mm, 0.1mm, 0.125mm, 0.15mm, 0.175mm, 0.2mm, 0.225mm, 0.25mm, 0.275mm or 0.3mm, or a range formed by any two of them. The above specific values of L4mm are only exemplary, and any value within the range of 0.05mm to 0.3mm is within the protection scope of the present disclosure. The present disclosure limits the thickness L4mm of the expansion adhesive layer 150 within the range of 0.05mm to 0.3mm, so as to further reasonably design the structure size of the expansion adhesive layer 150, reduce the occupation of the internal space of the shell 110 by the expansion adhesive layer 150, further accommodate more electrode assemblies 120 in the shell 110, thereby improving the space utilization of the electrode assemblies 120 in the shell 110, and finally improving the energy density of the single battery 100.

[0095] In another aspect, in the embodiments of the present disclosure, the present disclosure also provides an electric device, which comprises a device body and the monomer battery 100 as described above. The monomer battery 100 is installed in the device body to serve as a power supply for the electric device. The electric device as described above can be, but is not limited to, a small household appliance, a power tool, a terminal device, etc.

[0096] In another aspect, in the embodiments of the present disclosure, the present disclosure also provides a battery pack, which comprises a box body and the monomer battery 100 as described in any of the above embodiments. The monomer battery 100 is arranged in the box body.

[0097] In another aspect, in the embodiments of the present disclosure, the present disclosure also provides an electric device, which comprises a device body and the battery pack as described above. The battery pack is installed in the device body to serve as a power supply for the electric device. The electric device as described above can be, but is not limited to, a mobile device (such as a mobile phone, a notebook computer, etc.), an electric vehicle (such as a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship and a satellite, an energy storage system, etc.

[0098] In order to better understand the technical solutions of the present disclosure, the following further explains and describes by taking a lithium ion battery as an example.

[0099] The present embodiment provides a preparation method of a lithium ion battery, and the specific process is as follows:

[0100] 1. Preparation of positive electrode sheet

[0101] The positive electrode active material is lithium iron phosphate, the conductive agent is conductive carbon black SP, and the binder is PVDF, which are mixed in a mass ratio of 96:2:2. Then, NMP is added as a solvent for mixing. The system is stirred under vacuum until it becomes uniform. The positive electrode slurry is obtained. The positive electrode slurry is uniformly coated on both sides of the positive electrode current collector aluminum foil. Then, it is transferred to a 120°C oven for drying. After rolling, slitting and cutting, the positive electrode sheet is obtained.

[0102] 2. Preparation of negative electrode sheet

[0103] The negative electrode active material is graphite, the conductive agent is conductive carbon black SP, the thickening agent is CMC, and the binder is SBR, which are mixed in a mass ratio of 96.2:1.2:1.2:1.4. Then, deionized water is added as a solvent for mixing. The system is stirred under vacuum until it becomes uniform. The negative electrode slurry is obtained. The negative electrode slurry is uniformly coated on both sides of the negative electrode current collector copper foil. Then, it is transferred to a 110°C oven for drying. After rolling, slitting and cutting, the negative electrode sheet is obtained.

[0104] 3. Preparation of electrolyte

[0105] Ethylene carbonate (EC), methyl ethyl carbonate (EMC), diethyl carbonate (DEC) were mixed in a mass ratio of 3:4:3 to obtain an organic solvent, 1 mol / L LiPF6 was added and mixed uniformly, and then vinylene carbonate, vinyl sulfate and lithium difluorophosphate were added to prepare an electrolyte.

[0106] 4. Preparation of the separator

[0107] The PP film was used as the separator.

[0108] 5. Preparation of the lithium ion battery

[0109] The negative electrode sheet and the positive electrode sheet prepared by the above steps were dried, and then were wound together with the separator by using a winding machine to prepare a wound electrode roll. The positive electrode tab and the negative electrode tab were welded on the end cover, and the electrode assembly with the top cover welded was placed in an aluminum shell for packaging. After filling the electrolyte and forming the constant volume, a lithium ion battery was prepared.

[0110] In the lithium ion batteries of each example and the comparative example, the preparation method was the same as described above. The structure size and performance test data of each example and the comparative example were shown in Table 1 and Table 2.

[0111] In the lithium ion batteries of each example and the comparative example, the preparation method was the same as described above. The structure size and performance test data of each example and the comparative example were shown in Table 1 and Table 2.

[0112] In the lithium ion batteries of each example and the comparative example, the preparation method was the same as described above. The structure size and performance test data of each example and the comparative example were shown in Table 1 and Table 2.

[0113] The batteries prepared in the above examples and the comparative examples were tested for performance, and the method for the specific test items was as follows:

[0114] 1. Test method for heat dissipation performance of the lithium ion battery:

[0115] At 25℃, the lithium ion battery was placed for 30 min, and then was discharged at a constant current of 1C rate. After 10 min, the lithium ion battery was charged at a constant current and constant voltage of 1C rate. After 10 cycles of charge and discharge, the maximum temperature rise on the surface of the lithium ion battery was tested.

[0116] 2. Test method for energy density of the lithium ion battery:

[0117] At 25°C, the lithium-ion battery was left to stand for 30 minutes, then charged to the cutoff voltage at a 1C current, left to stand for 30 minutes, and then discharged to the cutoff voltage at a 1C current. The actual discharge energy was recorded. The lithium-ion battery was weighed using an electronic balance. The ratio of the actual 1C discharge energy to the weight is the actual energy density of the lithium-ion battery.

[0118] The relevant parameters and test results from the above embodiments and comparative examples are recorded in Table 1.

[0119] Table 1. Parameters and test results of Examples 1-18

[0120] As can be seen from the data in Table 1: In Example 17, although the energy density of the lithium-ion battery is relatively high, the maximum surface temperature rise of the lithium-ion battery is also relatively high. The lithium-ion battery does not exhibit the corresponding heat dissipation performance and does not meet the requirements. In Example 18, although the heat dissipation performance of the lithium-ion battery is relatively good, the density of the lithium-ion battery is relatively low. The lithium-ion battery does not exhibit the corresponding performance and does not meet the requirements.

[0121] Therefore, this disclosure, by limiting the ratio of the thickness L1mm of the second current collector 142 to the thickness L2mm of the housing 110 to be in the range of 1 to 1.5, limiting the thickness L1mm of the second current collector 142 to be in the range of 0.1mm to 1.5mm, and limiting the thickness L2mm of the housing 110 to be in the range of 0.1mm to 1mm, rationally designs the thickness structure of the second current collector 142, thereby further reducing the occupation of the current collector 140 on the internal space of the housing 110, allowing more electrode components 120 to be accommodated in the housing 110, thus improving the space utilization rate of the electrode components 120 in the housing 110, and ultimately improving the energy density of the single cell 100; at the same time, by limiting the ratio of the maximum dimension H2mm of the second current collector 142 in the first direction Z to the maximum dimension H1mm of the electrode component 120 in the first direction Z to be in the range of 0.01 to 1, and limiting the maximum area S1mm of the connection region 14211, this disclosure achieves a reasonable design of the thickness structure of the second current collector 142. 2 The maximum area S2mm of the contact surface 1421 2 The ratio is in the range of 0.3 to 1, so as to further rationally design the structural dimensions of the second current collector 142, ensure that the second current collector 142 has sufficient contact area to connect with the housing 110, further ensure that the current collector 140 can be fully utilized for heat dissipation when the single battery 100 is working normally, improve the heat dissipation performance of the single battery 100, and ultimately improve the safety performance of the single battery 100.

[0122] Table 2. Parameters and test results of Examples 1, 19-35

[0123] As can be seen from the data in Table 2, in Example 34, the energy density of the lithium ion battery is higher, but the maximum surface temperature rise of the lithium ion battery is also higher, and the lithium ion battery does not exhibit corresponding heat dissipation performance, which does not meet the requirements; in Example 35, the heat dissipation performance of the lithium ion battery is better, but the density of the lithium ion battery is lower, and the lithium ion battery does not exhibit corresponding performance, which does not meet the requirements.

[0124] It can be seen that, by limiting the thickness L3 of the first current collecting part 141 to be within the range of 0.05mm to 1mm and limiting the thickness L4 of the expansion adhesive layer 150 to be within the range of 0.01mm to 0.5mm, more electrode assemblies 120 can be accommodated in the shell 110, thereby improving the space utilization of the electrode assemblies 120 in the shell 110, and ultimately improving the energy density of the single battery 100; at the same time, by limiting the ratio of the maximum outer contour size D1 of the first current collecting part 141 to the maximum outer contour size D2 of the electrode assembly 120 to be within the range of 1.001 to 1.1, the structural size of the first current collecting part 141 is reasonably designed, so as to ensure that the first current collecting part 141 has sufficient contact area to connect with the electrode assembly 120, and to ensure that the single battery 100 can fully utilize the current collecting member 140 for heat dissipation when the single battery 100 is working normally, thereby improving the heat dissipation performance of the single battery 100, and ultimately improving the safety performance of the single battery 100.

[0125] The above steps provide an introduction for helping to understand the method, structure and core idea of the present disclosure. For those skilled in the art, without departing from the principles of the present disclosure, the present disclosure can be improved and modified in several ways, and these improvements and modifications also belong to the protection scope of the present disclosure. Industrial applicability

[0126] In summary, the present disclosure provides a single battery, a battery pack and an electric device, which has simple overall structure, low cost, and can improve the energy density of the single battery.

Claims

1. A monobloc battery, having a first direction (Z), wherein, The application relates to a battery, comprising: a shell (110); an electrode assembly (120) arranged in the shell (110); an end cover (130) arranged at one end of the shell (110) and connected with the shell (110); and a current collecting member (140) comprising a first current collecting part (141) and a second current collecting part (142) connected with each other, the first current collecting part (141) being arranged between the end cover (130) and the electrode assembly (120) and electrically connected with the electrode assembly (120), the second current collecting part (142) extending away from the end cover (130) in the first direction (Z), the second current collecting part (142) being arranged between the electrode assembly (120) and the shell (110) and electrically connected with the shell (110). The thickness of the second current collecting part (142) is L1 mm, the thickness of the shell (110) is L2 mm, and 1<=L1 / L2<=1.5 is satisfied.

2. The single battery as claimed in claim 1, wherein, The thickness L1 mm of the second current collecting part (142) also satisfies 0.1 mm<=L1<=1.5 mm.

3. The monobloc cell of claim 2, wherein, The thickness L2 mm of the shell (110) also satisfies 0.1 mm<=L2<=1 mm.

4. The monobloc cell of claim 2, wherein, The thickness of the first current collecting part (141) is L3 mm, and 0.05 mm<=L3<=1 mm is satisfied.

5. The single cell according to any one of claims 1 to 4, wherein The maximum outer contour size of the first current collecting part (141) is D1 mm, the maximum outer contour size of the electrode assembly (120) is D2 mm, and 1.001<=D1 / D2<=1.1 is satisfied.

6. The single cell according to any one of claims 1 to 4, wherein The maximum size of the electrode assembly (120) in the first direction (Z) is H1 mm, the maximum size of the second current collecting part (142) in the first direction (Z) is H2 mm, and 0.01<=H2 / H1<=1 is satisfied.

7. The single cell according to any one of claims 1 to 4, wherein The second current collecting part (142) has a contact surface (1421) having a connecting area (14211), and the second current collecting part (142) is electrically connected with the shell (110) through the connecting area (14211).

8. The single cell according to any one of claims 1 to 4, wherein The application further comprises: The maximum area of the connection region (14211) is S1 mm 2 The maximum area of the contact surface (1421) is S2 mm 2 0.3 ≤ S1 / S2 ≤ 1 is satisfied.

9. The single cell according to any one of claims 1 to 4, wherein an expanded adhesive layer (150), at least part of which is arranged between the electrode assembly (120) and the second current collecting part (142). The thickness of the expanded adhesive layer (150) is L4 mm, and 0.01 mm<=L4<=0.5 mm is satisfied.

10. The monobloc cell of claim 9, wherein, The expanded adhesive layer (150) is an insulating expanded adhesive.

11. The monobloc cell of claim 9, wherein, The first current collecting part (141) is electrically connected with the positive or negative tab of the electrode assembly (120).

12. The monobloc cell of any one of claims 1-4, wherein, The shell (110) is cylindrical, and the second current collecting part (142) is also cylindrical; the second current collecting part (142) is sleeved on the outer periphery of the electrode assembly (120) and the inner periphery of the shell (110).

13. The monobloc cell of any one of claims 1-4, wherein, The first current collecting part (141) is arranged at one end of the second current collecting part (142) close to the end cover (130).

14. The monobloc cell of claim 13, wherein, The first current collecting part (141) is circular.

15. The monobloc cell of claim 13, wherein, The first current collecting part (141) is a hollow circular ring.

16. The monobloc cell of claim 15, wherein, ​ 17. The monobloc cell of any one of claims 1-4, wherein, The first current collecting portion (141) is integrally formed with the second current collecting portion (142).

18. A battery pack, wherein, Comprising: a case; and The unit cell according to any one of claims 1 to 17 is provided in the case.

19. An electrical device, comprising: Comprising a device main body; and The unit cell according to any one of claims 1 to 17 is provided in the device main body.

20. An electrical device, comprising: Comprising a device main body; and The battery pack according to claim 18 is provided in the device main body.

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