Battery Cells and Battery Packs

Abstract

The present invention relates to the field of battery technology, and in particular to a battery cell and a battery pack. The battery cell comprises: an insulating film used to cover a connecting piece and a pole group, and a positioning hole is formed on the insulating film; a cover plate assembly is formed with a clamping piece protruding toward the inside of the battery cell, and before the insulating film covers the pole group, the clamping piece extends into the positioning hole, and the clamping piece comprises a plurality of claws arranged at intervals, and the claw portion comprises an extension portion connected to the cover plate assembly and a clamping portion arranged at one end of the extension portion away from the cover plate assembly, and the insulating film is clamped between the clamping portion and the cover plate assembly, so that the insulating film is fixedly connected to the cover plate assembly. The present invention enhances the insulation isolation between the connecting piece and the pole ear and the shell, prevents the risk of direct overlap or metal wire overlap between the connecting piece or the pole ear and the shell, and improves the battery cell and production yield, as well as the safety performance of the battery cell and the battery pack.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery cell and a battery pack. Background Art

[0002] As lithium-ion battery technology becomes increasingly mature, lithium-ion batteries are widely used as power batteries in electric vehicles and energy storage fields, and the requirements for the performance and safety of lithium-ion batteries are increasing.

[0003] Traditional lithium batteries are assembled by first assembling the electrode group, connecting piece, and cover plate, then wrapping Mylar film from the bottom, and finally inserting the shell into the shell for welding and sealing the cover plate. Specifically, Mylar is wrapped from the bottom of the electrode group upwards, and then Mylar is hot-melted to the lower plastic on the cover plate. Because the connection strength of the hot-melt area is insufficient, there is a risk of Mylar tearing or falling off at the hot-melt area when the battery cell is pulled. In addition, due to the size chain such as assembly tolerance, there is a risk that the connecting piece and the pole ear are close to or in direct contact with the shell, which will cause a short circuit during the use of the battery cell, affecting the safety of the battery cell. Summary of the invention

[0004] In view of this, the purpose of the present application is to provide a battery cell and a battery pack to solve the problem that the existing battery cell assembly method is prone to the risk of Mylar tearing and falling off, and the connecting piece and the tab are prone to contact with the shell to cause a short circuit, affecting the service life and safety of the battery cell and the battery pack.

[0005] A first aspect of the present invention provides a battery cell, wherein the battery cell comprises:

[0006] Connecting piece;

[0007] A pole group is formed with a protruding pole ear, and the pole ear is connected to the connecting piece;

[0008] An insulating film, used for covering the connecting piece and the electrode group, wherein the insulating film is provided with a positioning hole;

[0009] The cover plate assembly is formed with a clamping piece protruding toward the interior of the battery cell. Before the insulating film covers the connecting piece and the electrode group, the clamping piece extends into the positioning hole. The clamping piece includes a plurality of claw portions arranged at intervals. The claw portion includes an extension portion connected to the cover plate assembly and a clamping portion arranged at one end of the extension portion away from the cover plate assembly. The insulating film is clamped between the clamping portion and the cover plate assembly, so that the insulating film is fixedly connected to the cover plate assembly.

[0010] Preferably, the size of two adjacent extension portions in the first direction is b, 1mm≤b≤10mm;

[0011] The size of two adjacent clamping parts in the first direction is d, db≥0.1mm;

[0012] In the first direction, the distance between two adjacent claw portions is a, bd-0.5mm≤a≤b-0.5mm.

[0013] Preferably, the thickness of the insulating film is t, 0.05 mm≤t≤1 mm, and the dimension of the extending portion in the second direction is h, h≥t.

[0014] Preferably, the battery cell further comprises a shell, and the insulating film is installed in the shell after covering the connecting sheet and the electrode group;

[0015] The dimension of the inner wall of the shell in the first direction is A; after the insulating film covers the connecting piece and the pole group, the dimension of the insulating film in the first direction is w; the dimension of the pole group in the first direction is T; T-1mm≤w≤A-0.5mm;

[0016] And / or, the dimension of the inner wall of the shell in the third direction is K; after the insulating film covers the connecting plate and the pole group, the dimension of the insulating film in the third direction is E; the dimension of the pole group in the third direction is L; L-1mm≤E≤K-0.5mm.

[0017] Preferably, after the insulating film is fixed to the cover plate assembly, the insulating film is formed into attachment portions on both sides of the cover plate assembly in the first direction, and the attachment portions are bent toward the electrode group so that part of the attachment portions is attached to both sides of the electrode group in the first direction;

[0018] The attachment portion on each side is formed as a edging portion at both ends in the third direction, and the edging portion is bent so that the edging portions on both sides of the pole group in the first direction at least partially overlap to form an overlapping area, and are attached to both sides of the pole group in the third direction.

[0019] Preferably, after being bent, the edging portion is transitionally connected to the attached portions attached to the two side portions of the pole group in the first direction by an arc, and the radius of the arc is R; the size of the overlapping area in the first direction is c; after the insulating film covers the connecting plate and the pole group, the size of the insulating film in the first direction is w; 2mm≤c≤w-2R.

[0020] Preferably, the cover plate assembly includes an insulating member, which is hot-melt connected to at least part of the overlapping area to form a hot melt zone, and the size of the hot melt zone in the first direction is g, g ≥ 3mm, c ≥ g + 0.2mm; the size of the hot melt zone in the second direction is f, f ≥ 1mm; the gap between the end of the insulating member facing the inside of the battery cell and the bottom of the hot melt zone is J, J ≥ 0.2mm.

[0021] Preferably, the end of the attachment portion away from the cover plate assembly is formed as a closing portion, and the closing portion is bent so that it is attached to the end of the pole group away from the cover plate assembly; the angle between the longest side and the shortest side of the closing portion is Y, Y≤45°; the dimension of the pole group in the first direction is T, and the width dimension of the closing portion is X, 3mm≤X≤T / 2.

[0022] Preferably, the battery cell also includes a bottom support, and after the insulating film covers the connecting plate and the pole group, the bottom support is arranged at an end of the insulating film away from the cover plate assembly, and the bottom support covers the bottom of the insulating film and the circumferential side wall of the insulating film portion, and the overlapping height dimension of the bottom support and the insulating film in the second direction is H, H≥0.2mm; the distance between the bottom support and the insulating film in the first direction is G, G≥0mm.

[0023] A second aspect of the present invention provides a battery pack, comprising the battery cell described in any of the above technical solutions.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The battery cell of the present invention is provided with a positioning hole on the insulating film; the cover plate assembly is formed with a clamping piece protruding toward the inside of the battery cell, and the clamping piece extends into the positioning hole before the insulating film covers the connecting piece and the pole group, so that the insulating film is first clamped and fixed to the cover plate assembly before covering the pole group, and then the connecting piece and the pole group are covered, thereby reducing the risk of the insulating film being torn or even falling off, and also enhancing the insulation isolation between the connecting piece and the pole ear and the shell, preventing the risk of direct overlap or metal wire overlap between the connecting piece or the pole ear and the shell, thereby improving the battery cell and production yield, as well as the safety performance of the battery cell and the battery pack.

[0026] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 A schematic diagram of the assembly structure of the insulating film in the battery cell provided by an embodiment of the present invention and the cover plate assembly in an unfolded state;

[0029] Figure 2 A schematic diagram of the assembly structure of the insulating film in the battery cell provided by the embodiment of the present invention in a folded state with the electrode group, the connecting sheet and the bottom support member;

[0030] Figure 3 A schematic diagram of the assembly structure of the insulating film of the battery cell provided by the embodiment of the present invention in a folded state, the electrode group and the bottom support member from another viewing angle;

[0031] Figure 4 For along Figure 3 The cross-section taken at AA in the middle;

[0032] Figure 5 for Figure 4 A schematic diagram of the enlarged structure at B in the middle;

[0033] Figure 6 for Figure 4 Schematic diagram of the enlarged structure at C in the middle;

[0034] Figure 7 A schematic diagram of the assembly structure of the insulating film of the battery cell provided by the embodiment of the present invention in a folded state, the electrode group and the bottom support member at another viewing angle;

[0035] Figure 8 A schematic diagram of the positional relationship of the electrode group in the battery cell provided in an embodiment of the present invention within the housing;

[0036] Fig. 9 A schematic diagram of the positional relationship of the electrode group of the battery cell provided by an embodiment of the present invention in the housing from another viewing angle;

[0037] Fig.10 A schematic diagram of the structure of an insulating film with a closing portion in a battery cell provided in an embodiment of the present invention;

[0038] Fig.11 A schematic diagram of the structure of the battery cell provided by an embodiment of the present invention when the attaching portion and the edge wrapping portion of the insulating film with the closing portion wrap the electrode group and the connecting sheet;

[0039] Fig.12A schematic structural diagram of a battery cell provided by an embodiment of the present invention having an insulating film with a closed opening when the electrode group is covered with the closed opening;

[0040] Fig.13 A schematic diagram of the assembly structure of the insulating film and the shell in the battery cell provided by an embodiment of the present invention;

[0041] Fig.14 A cross-sectional view of the assembly structure of the insulating film, the electrode group and the connecting sheet in the battery cell provided by an embodiment of the present invention.

[0042] Icons: 10-insulating film; 11-positioning hole; 101-attachment part; 102-edging part; 103-closing part; 111-overlapping area; 112-hot melting area; 20-cover assembly; 21-clamping part; 211-claw part; 2111-extension part; 2112-clamping part; 22-insulating part; 23-pole; 30-housing; 40-pole group; 41-pole ear; 50-bottom support; 60-connecting piece; D1-first direction; D2-second direction; D3-third direction. DETAILED DESCRIPTION

[0043] The following specific embodiments are provided to help the reader obtain a comprehensive understanding of the methods, devices and / or systems described herein. However, after understanding the disclosure of the present application, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent. For example, the order of operations described herein is merely an example, and is not limited to the order set forth herein, but in addition to the operations that must occur in a particular order, changes that will be apparent after understanding the disclosure of the present application may be made. In addition, in order to improve clarity and brevity, descriptions of features known in the art may be omitted.

[0044] The features described herein may be implemented in different forms and should not be interpreted as being limited to the examples described herein. Rather, the examples described herein have been provided only to illustrate some of the many possible ways of implementing the methods, devices and / or systems described herein that will be apparent after understanding the disclosure of the present application.

[0045] Throughout the specification, when an element (such as a layer, a region, or a substrate) is described as being “on”, “connected to”, “bound to”, “over”, or “covering” another element, it may be directly “on”, “connected to”, “bound to”, “over”, or “covering” another element, or one or more other elements may be present between them. In contrast, when an element is described as being “directly on”, “directly connected to”, “directly bound to”, “directly over”, or “directly covering” another element, there may be no other elements present between them.

[0046] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items.

[0047] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are only used to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Therefore, without departing from the teachings of the examples described herein, the first member, component, region, layer, or portion referred to may also be referred to as the second member, component, region, layer, or portion.

[0048] For ease of description, spatial relational terms such as "above", "upper", "below", and "lower" may be used herein to describe the relationship of one element to another element as shown in the accompanying drawings. Such spatial relational terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the accompanying drawings. For example, if the device in the accompanying drawings is turned over, an element described as being "above" or "upper" relative to another element will subsequently be "below" or "lower" relative to the other element. Therefore, the term "above" includes both "above" and "below" orientations depending on the spatial orientation of the device. The device may also be positioned in other ways (e.g., rotated 90 degrees or in other orientations), and the spatial relational terms used herein will be interpreted accordingly.

[0049] The terms used herein are only used to describe various examples and are not used to limit the present disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms "include", "comprise" and "have" list the stated features, quantities, operations, components, elements and / or their combinations that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or their combinations.

[0050] Variations in the shapes shown in the drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0051] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0052] According to a first aspect of the present invention, a battery cell is provided, which specifically includes a connecting sheet 60 , an electrode group 40 , an insulating film 10 and a cover plate assembly 20 .

[0053] Hereinafter, a specific structure of the battery cell according to this embodiment will be described.

[0054] In this embodiment, if Figure 1 and Fig.14 As shown, the electrode group 40 is formed with a protruding pole ear 41, one end of the connecting piece 60 is connected to the pole ear 41 on the electrode group 40, and the other end of the connecting piece 60 is connected to the pole 23 in the cover plate assembly 20. The insulating film 10 is used to cover the electrode group 40 and the connecting piece 60 to play an insulating role to avoid short circuit. The insulating film 10 can be Mylar; before the insulating film 10 covers the electrode group 40 and the connecting piece 60, that is, the insulating film 10 is formed into a sheet structure in the unfolded state, and a positioning hole 11 is opened on the insulating film 10; the cover plate assembly 20 is formed with a clamping piece protruding toward the inside of the battery cell 21. Before the insulating film 10 covers the electrode group 40 and the connecting piece 60, the clamp 21 extends into the positioning hole 11, so that the insulating film 10 is first positioned and assembled with the cover plate assembly 20 and then covers the electrode group 40. This reduces the risk of the insulating film 10 being torn or even falling off, and enables the insulating film 10 to cover the connecting piece 60 and the electrode group 40, and also enhances the insulation isolation between the connecting piece 60 and the pole ear 41 and the shell 30, and prevents the risk of direct overlap or metal wire overlap between the connecting piece 60 or the pole ear 41 and the shell 30, thereby improving the production yield of the battery cell and the safety performance of the battery cell.

[0055] It should be noted that the insulating film 10 is provided with an opening so that a portion of the connecting piece 60 can be connected to the pole 23 on the cover plate assembly 20 .

[0056] Furthermore, in this embodiment, if Figure 4 and Figure 5 As shown, the clamping member 21 is formed as a claw structure, and the clamping member 21 includes a plurality of claw portions 211 arranged at intervals, and the claw portion 211 includes an extension portion 2111 connected to the cover assembly 20 and a clamping portion 2112 arranged at one end of the extension portion 2111 away from the cover assembly 20, the extension portion 2111 can be formed as a columnar or pin-shaped structure, and the clamping portion 2112 can be formed as a bump-shaped structure, and the insulating film 10 is clamped between the clamping portion 2112 and the cover assembly 20, so that the insulating film 10 is fixedly connected to the cover assembly 20.

[0057] Preferably, there are multiple clamping members 21, and the multiple clamping members 21 are arranged at intervals around the cover assembly 20 to ensure that the insulating film 10 and the cover assembly 20 are firmly and reliably fixed; preferably, the multiple clamping members 21 are symmetrically arranged along the first direction D1 or the third direction D3 to ensure uniform force. The setting position of the clamping member 21 on the cover assembly 20 is preferably close to the edge of the cover assembly 20, so that the insulating film 10 is easily fixed and wrinkles are not easy to appear.

[0058] In addition, the number of the claw portions 211 in each clamping member 21 may be two, and the protruding directions of the clamping portions 2112 on the two claw portions 211 are arranged opposite to each other to prevent the insulating film 10 from being loosened from the clamping member 21 .

[0059] Furthermore, in this embodiment, if Figure 5 As shown, the size of two adjacent extension parts 2111 in the first direction D1 is b, 1mm≤b≤10mm, so as to avoid the situation that the size of b is too small, resulting in insufficient strength of the extension part 2111 and causing the claw part 211 to break, and it can also avoid the problem that the size of b is too large and occupies space and has high cost; the size of two adjacent clamping parts 2112 in the first direction D1 is d, db≥0.1mm, so as to prevent the insulating film 10 from falling off the clamping part 21 and the clamping failure of the clamping part 21; in the first direction D1, the distance between two adjacent clamping claw parts 211 is a, bd-0.5mm≤a≤b-0.5mm, so as to avoid the size of a being too small, resulting in insufficient elasticity of the clamping part 21 so that the clamping part 21 cannot extend into the positioning hole 11 on the insulating film 10, and it can also avoid the situation that the size of a is too large, resulting in insufficient strength of the clamping claw part 21 and causing breakage during assembly.

[0060] Furthermore, in this embodiment, if Figure 5As shown, the thickness of the insulating film 10 is t, 0.05mm≤t≤1mm, so as to avoid the insulating film 10 being too thin, resulting in insufficient insulation withstand voltage and being broken down, and also to avoid the insulating film 10 being too thick and difficult to bend, thereby failing to effectively cover the electrode group 40; the size of the extension portion 2111 in the second direction D2 is h, h≥t, so as to ensure that the clamping piece 21 is firmly clamped to the insulating film 10.

[0061] In a first preferred embodiment, Figure 1 , Figure 2 and Figure 7 As shown, after the insulating film 10 is fixed to the cover plate assembly 20, the insulating film 10 is formed as an attachment portion 101 on both sides of the cover plate assembly 20 in the first direction D1, and the attachment portion 101 is bent toward the pole group 40, so that part of the attachment portion 101 is attached to the two sides of the pole group 40 in the first direction D1; the attachment portion 101 on each side is formed as an edge portion 102 at both ends in the third direction D3, and the edge portion 102 is bent so that the edge portions 102 on both sides of the pole group 40 in the first direction D1 at least partially overlap to form an overlapping area 111, and are attached to the two sides of the pole group 40 in the third direction D3, thereby achieving full circumferential covering of the circumferential side wall of the pole group 40.

[0062] like Figure 7 and Fig.13 As shown, after the edge portion 102 is bent, it is connected to the attachment portion 101 on both sides of the electrode group 40 in the first direction D1 by an arc transition, and the radius of the arc is R; the size of the overlapping area 111 in the first direction D1 is c; after the insulating film 10 covers the electrode group 40 and the connecting piece 60, the size of the insulating film 10 in the first direction D1 is w; 2mm≤c≤w-2R, so as to avoid the size of c being too small to cause the electrode group 40 to be exposed, affecting the insulating protection effect of the insulating film 10, and also to avoid the size of c being too large to cover the bent arc, and the insulating film 10 is prone to warping of the burrs. Since the inner wall of the shell 30 is also an arc-shaped edge, it will interfere with the warped burrs of the insulating film 10, making it difficult to enter the shell.

[0063] In this embodiment, if Figure 1 and Figure 7As shown, the cover assembly 20 includes an insulating member 22 and a cover body, and the insulation is arranged on the side of the cover body facing the inside of the battery cell. The insulating member 22 is hot-melt connected with at least part of the overlapping area 111 to form a hot-melt zone 112, so as to ensure that the two overlapping edge portions 102 will not fall apart. Specifically, the size of the hot-melt zone 112 in the first direction D1 is g, g ≥ 3mm, and the size of the hot-melt zone 112 in the second direction D2 is f, f ≥ 1mm, so as to ensure the strength of the hot-melt connection; the gap between the end of the insulating member 22 facing the inside of the battery cell and the bottom of the hot-melt zone 112 is J, J ≥ 0.2mm, so as to avoid the insulating film 10 from melting and forming a gap, thereby affecting the insulation performance. Preferably, c ≥ g + 0.2mm, so as to ensure that the hot-melt zone 112 is formed in the overlapping area 111, and the two overlapping edge portions 102 are firmly attached.

[0064] In a second preferred embodiment, Figure 4 , Fig. 9 , Figures 10 to 12 As shown, on the basis of the first preferred embodiment described above, one end of the attachment portion 101 away from the cover plate assembly 20 is formed as a closing portion 103, and the closing portion 103 is bent so that it is attached to the end of the pole group 40 away from the cover plate assembly 20, so that the insulating film 10 can cover the six surfaces of the pole group 40; the angle between the longest side and the shortest side of the closing portion 103 is Y (that is, the two ends of the closing portion 103 in the length direction are angled with the length direction of the closing portion 103 (that is, the third direction D3) to form an angle Y), Y≤45°; the dimension of the pole group 40 in the first direction D1 is T, and the width dimension of the closing portion 103 is X, 3mm≤X≤T / 2, so as to ensure that the adjacent closing portions 103 will not overlap each other after bending, thereby avoiding increasing the thickness dimension of the insulating film 10 in the second direction D2 in the folded state, ensuring flatness, and facilitating connection with the bottom support member 50 described below.

[0065] In this embodiment, if Figure 4 and Figure 6 As shown, the battery cell further includes a bottom support 50. After the insulating film 10 covers the electrode group 40, the bottom support 50 is arranged at one end of the insulating film 10 away from the cover plate assembly 20. The bottom support 50 and the electrode group 40 covered with the insulating film 10 are put into the shell together (i.e., assembled into the shell 30 described below) to prevent the insulating film 10 from wrinkling or being damaged during the shell insertion process. The bottom support 50 and the insulating film 10 can be fixed by adhesive tape.

[0066] Specifically, Figure 6As shown, the bottom support member 50 covers the bottom of the insulating film 10 and part of the circumferential side wall of the insulating film 10. In the second direction D2, the overlapping height dimension of the bottom support member 50 and the insulating film 10 in the second direction D2 is H, H≥0.2mm, so as to ensure that there is no obvious gap after the adhesive tape is bonded and fixed; in the first direction D1, the distance between the bottom support member 50 and the insulating film 10 is G, G≥0mm, so as to ensure that the bottom of the bottom support member 50 is flat, and ensure that the bottom support member 50 and the bottom of the shell 30 are in contact after being inserted into the shell.

[0067] In this embodiment, if Figure 3 , Figure 7 , Figure 8 and Fig. 9 As shown, the battery cell also includes a shell 30, and the insulating film 10 is installed in the shell 30 after covering the electrode group 40; the size of the inner wall of the shell 30 in the first direction D1 is A; after the insulating film 10 covers the electrode group 40, the size of the insulating film 10 in the first direction D1 is w; the size of the electrode group 40 in the first direction D1 is T; T-1mm≤w≤A-0.5mm; and / or the size of the inner wall of the shell 30 in the third direction D3 is K; after the insulating film 10 covers the electrode group 40, the size of the insulating film 10 in the third direction D3 is E; the size of the electrode group 40 in the third direction D3 is L; L-1mm≤E≤K-0.5mm, so that the insulating film 10 can be conveniently bent and covered and the shell can be smoothly inserted.

[0068] In this embodiment, the first direction D1, the second direction D2 and the third direction D3 are arranged perpendicular to each other. For example, when the cover plate assembly 20 is formed into a rectangle, the third direction D3 may be the length direction of the cover plate assembly 20, the first direction D1 may be the width direction of the cover plate assembly 20, and the second direction D2 may be the direction in which the pole group 40 extends into the housing 30.

[0069] In order to verify whether the battery cell structure of the present invention can better complete the fixation, insulation and assembly, multiple groups of battery cells are assembled and the assembled battery cells are subjected to vibration tests. The assembly conditions and vibration test results are shown in the following table:

[0070]

[0071] The failure mode " / " in the table indicates that no abnormality occurs in the battery cell during assembly and after the vibration test. Referring to the parameters in the above table, it can be seen that in Examples 1 to 7, the parameters of T, A, L, K, w, E, g, c, f and J are all within the specified range, and no abnormality is found in the battery cell during assembly and after the vibration test. Different failure conditions occur in Comparative Examples 1 to 5. Specifically, in Comparative Examples 1 and 2, it is difficult to put the pole group 40 into the shell during the battery cell assembly process, which is mainly caused by the excessive size of w or E; in Comparative Examples 3 and 4, after the battery cell vibration test was disassembled, it was found that the hot melting point between the insulating film 10 and the pole group 40 fell off (that is, the hot melting area 112 was disconnected), which was mainly due to the insufficient strength of the hot melting connection caused by the small size of g or f; in Comparative Example 5, the insulating film 10 was melted during the hot melting process, resulting in a gap on the insulating film 10, which was mainly caused by the small size of J, so that the insulation performance of the battery cell could not be guaranteed.

[0072] According to a battery cell provided by the present invention, a positioning hole is opened on the insulating film; the cover plate assembly is formed with a clamping piece protruding toward the inside of the battery cell, and the clamping piece extends into the positioning hole before the insulating film covers the pole group and the connecting piece. In this way, the insulating film is first clamped and fixed to the cover plate assembly before covering the pole group, and then the connecting piece and the pole group are covered, thereby reducing the risk of the insulating film being torn or even falling off, and enhancing the insulation isolation between the connecting piece and the pole ear and the shell, preventing the risk of direct overlap or metal wire overlap between the connecting piece or the pole ear and the shell, thereby improving the battery cell and production yield as well as the safety performance of the battery cell.

[0073] A battery pack provided according to the present invention includes the battery cell as described above, wherein a plurality of battery cells are arranged in series and / or in parallel, and during the assembly process of the battery cell, the insulating film and the cover plate assembly are first assembled and then the insulating film is used to cover the electrode group, so that the connecting piece and the electrode ear are both covered by the insulating film, thereby preventing the risk of direct overlap between the connecting piece or the electrode ear and the shell or overlap of the metal wire, thereby effectively improving the safety performance of the battery pack.

[0074] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present application, which are used to illustrate the technical solutions of the present application, rather than to limit them. The protection scope of the present application is not limited thereto. Although the present application is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present application, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A battery cell, characterized in that: The battery cell comprises: Connecting piece; A pole group is formed with a protruding pole ear, and the pole ear is connected to the connecting piece; An insulating film, used for covering the connecting piece and the electrode group, wherein the insulating film is provided with a positioning hole; The cover plate assembly is formed with a clamping piece protruding toward the inside of the battery cell, the clamping piece extends into the positioning hole before the insulating film covers the connecting piece and the electrode group, the clamping piece includes a plurality of claws arranged at intervals, the claws include an extension connected to the cover plate assembly and a clamping part arranged at one end of the extension away from the cover plate assembly, the insulating film is sandwiched between the clamping part and the cover plate assembly, so that the insulating film is fixedly connected to the cover plate assembly; The size of two adjacent extension portions in the first direction is b, 1 mm ≤ b ≤ 10 mm; The size of two adjacent clamping parts in the first direction is d, db≥0.1mm; In the first direction, the distance between two adjacent claw portions is a, bd-0.5mm≤a≤b-0.5mm.

2. The battery cell according to claim 1, characterized in that: The thickness of the insulating film is t, 0.05 mm≤t≤1 mm, and the dimension of the extending portion in the second direction is h, h≥t.

3. The battery cell according to claim 1, characterized in that: The battery cell further comprises a shell, and the insulating film is installed in the shell after covering the connecting sheet and the electrode group; The dimension of the inner wall of the shell in the first direction is A; after the insulating film covers the connecting piece and the pole group, the dimension of the insulating film in the first direction is w; the dimension of the pole group in the first direction is T; T-1mm≤w≤A-0.5mm; And / or, the dimension of the inner wall of the shell in the third direction is K; after the insulating film covers the connecting plate and the pole group, the dimension of the insulating film in the third direction is E; the dimension of the pole group in the third direction is L; L-1mm≤E≤K-0.5mm.

4. The battery cell according to claim 1, characterized in that: After the insulating film is fixed to the cover plate assembly, the insulating film is formed into attachment portions on both sides of the cover plate assembly in the first direction, and the attachment portions are bent toward the electrode group so that part of the attachment portions is attached to both sides of the electrode group in the first direction; The attachment portion on each side is formed as a edging portion at both ends in the third direction, and the edging portion is bent so that the edging portions on both sides of the pole group in the first direction at least partially overlap to form an overlapping area, and are attached to both sides of the pole group in the third direction.

5. The battery cell according to claim 4, characterized in that: After being bent, the edging portion is transitionally connected with the attached portions attached to the two sides of the pole group in the first direction in a circular arc, and the radius of the circular arc is R; the size of the overlapping area in the first direction is c; after the insulating film covers the connecting plate and the pole group, the size of the insulating film in the first direction is w; 2mm≤c≤w-2R.

6. The battery cell according to claim 5, characterized in that: The cover plate assembly includes an insulating member, which is hot-melt connected to at least part of the overlapping area to form a hot-melt zone, and the size of the hot-melt zone in the first direction is g, g≥3mm, c≥g+0.2mm; the size of the hot-melt zone in the second direction is f, f≥1mm; the gap between the end of the insulating member facing the inside of the battery cell and the bottom of the hot-melt zone is J, J≥0.2mm.

7. The battery cell according to claim 4, characterized in that: The end of the attachment portion away from the cover plate assembly is formed as a closing portion, and the closing portion is bent so that it is attached to the end of the pole group away from the cover plate assembly; the angle between the longest side and the shortest side of the closing portion is Y, Y≤45°; the dimension of the pole group in the first direction is T, and the width dimension of the closing portion is X, 3mm≤X≤T / 2.

8. The battery cell according to claim 4, characterized in that: The battery cell also includes a bottom support. After the insulating film covers the connecting plate and the pole group, the bottom support is arranged at an end of the insulating film away from the cover plate assembly. The bottom support covers the bottom of the insulating film and the circumferential side wall of the insulating film portion. The overlapping height dimension of the bottom support and the insulating film in the second direction is H, H≥0.2mm; the distance between the bottom support and the insulating film in the first direction is G, G≥0mm.

9. A battery pack, characterized in that: A battery cell comprising any one of claims 1 to 8.

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