Battery cell assembly and battery monomer

Abstract

The utility model relates to a battery cell assembly and a battery monomer. The battery cell assembly comprises a shell and a battery cell, wherein the shell is provided with a circumferential wall and a welding wall arranged at the end part of the circumferential wall; the battery cell is arranged in the shell and comprises a cell body, an insulating film and an electrode tab, the insulating film wraps the cell body, and the electrode tab is arranged at the end, corresponding to the welding wall, of the cell body in a protruding mode and penetrates out of the insulating film; the electrode tab comprises a welding part located between the welding wall and the insulating film and a tail part connected with the welding part and located between the circumferential wall and the insulating film. The battery cell assembly can effectively prevent the electrode tabs from being inserted into the battery cell.

Description

Technical Field

[0001] The present application relates to the field of new energy technology, and in particular to a battery core assembly and a battery cell. Background Art

[0002] A battery cell generally includes a cell assembly and an electrolyte encapsulated in the cell assembly. The cell assembly generally includes a shell and a cell disposed in the shell. The cell generally has a core body and an electrode tab protruding from the outside of the core body. In some types of battery cells (e.g., cylindrical battery cells), the shell has a welding wall, the welding wall is arranged opposite to the side of the core body with the electrode tab, and the electrode tab is located between the welding wall and the side of the core body with the electrode tab and is welded to the welding wall. The electrode tab of this type of battery cell is easily bent under pressure and inserted into the battery cell, causing the electrode tab to contact the pole piece with the opposite electrical property to itself, which in turn causes the battery cell to short-circuit or even catch fire. Utility Model Content

[0003] Based on this, it is necessary to provide a battery cell assembly that can effectively prevent the electrode tabs from being inserted into the battery cell in order to address the above-mentioned problem.

[0004] A battery cell assembly, comprising:

[0005] A housing having a circumferential wall and a welding wall provided at an end of the circumferential wall; and

[0006] A battery cell is arranged in the shell, and the battery cell includes a core body, an insulating film and an electrode tab. The insulating film is coated on the outside of the core body, and the electrode tab is protruded at the end of the core body corresponding to the welding wall and passes through the outside of the insulating film. The electrode tab includes a welding portion located between the welding wall and the insulating film and a tail portion connected to the welding portion and located between the circumferential wall and the insulating film.

[0007] In some optional embodiments, the electrode tab further includes an arc-shaped transition portion connecting the welding portion and the tail portion.

[0008] In some optional embodiments, an insulating structure is further included within the shell, wherein the insulating structure is sleeved outside one end of the battery cell close to the welding wall, and the insulating structure includes a fixing portion between the welding wall and the battery cell and a connecting portion connected to the fixing portion and located between the circumferential wall and the battery cell, wherein the connecting portion is connected to the battery cell.

[0009] In some optional embodiments, the insulating structure is made of polypropylene; and / or

[0010] The thickness of the insulating structure is 0.5-0.9 mm; and / or

[0011] The connecting portion is arranged perpendicular to the surface where the fixing portion is located; and / or

[0012] The connecting portion has at least one recessed groove on a side away from the fixing portion; and / or

[0013] The fixing portion has a welding through hole, and the welding portion is welded to the welding wall through the welding through hole; and / or

[0014] The connecting portion is connected to the battery core by gluing.

[0015] In some optional embodiments, the connecting portion has a notch for exposing the tail portion outside the connecting portion.

[0016] In some optional embodiments, the fixing portion extends from the notch to between the battery core and the circumferential wall to form a limiting portion located between the battery core and the circumferential wall for limiting the tail portion.

[0017] In some optional embodiments, the notch extends from a side of the connecting portion away from the fixing portion to the fixing portion, and the insulating structure can be sleeved outside an end of the battery core close to the welding wall through the notch.

[0018] In some optional embodiments, in the circumferential direction of the connecting portion, connecting lines at both ends of the connecting portion divide the fixing portion into a first portion connected to the connecting portion and a second portion connected to the first portion, and the width of the second portion gradually decreases in a direction away from the first portion.

[0019] In some optional embodiments, the shell further includes a pole wall disposed at the other end of the circumferential wall, the pole wall being provided with a pole insulated from the pole wall, the battery cell further includes a pole ear, the pole ear protruding from the end of the core body corresponding to the pole wall and extending out of the insulating film, the pole ear being welded and electrically connected to the pole, one of the electrode ear and the pole ear being a positive pole ear, and the other being a negative pole ear; and / or

[0020] The shell and the battery core are both cylindrical.

[0021] The present application also provides a battery cell, comprising the above-mentioned battery cell assembly.

[0022] In the above-mentioned battery cell assembly, the electrode tab includes a welding portion located between the welding wall and the insulating film and a tail portion connected to the welding portion and located between the circumferential wall and the insulating film, that is, the electrode tab extending from the insulating film will "step back" toward the direction close to the circumferential wall and extend between the circumferential wall and the insulating film, so that the electrode tab includes a welding portion located between the welding wall and the insulating film and a tail portion connected to the welding portion and located between the circumferential wall and the insulating film. The tail portion of the electrode tab is located between the circumferential wall and the insulating film, which can effectively avoid the situation in which the electrode tab is compressed and bent during assembly, welding, transportation and use, resulting in the tail portion of the electrode tab being inserted into the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a structural schematic diagram of a battery cell assembly in one embodiment of the present application;

[0025] Figure 2 For along Figure 1 The cross-sectional view of line VV in ;

[0026] Figure 3 is a schematic diagram of a three-dimensional structure of an insulation structure in an embodiment of the present application;

[0027] Figure 4 for Figure 3 A top view of the insulating structure shown;

[0028] Figure 5 is a schematic diagram of a three-dimensional structure of an insulation structure in another embodiment of the present application;

[0029] Figure 6 for Figure 5 A top view of the insulating structure shown;

[0030] Figure 7 is a schematic diagram of a three-dimensional structure of an insulation structure in another embodiment of the present application;

[0031] Figure 8 is a schematic diagram of a three-dimensional structure of an insulation structure in another embodiment of the present application;

[0032] Fig. 9 is a schematic diagram of a three-dimensional structure of an insulation structure in another embodiment of the present application;

[0033] Fig.10is a schematic diagram of a three-dimensional structure of an insulation structure in another embodiment of the present application;

[0034] Fig.11 It is an assembly preparation diagram of a battery cell and an insulation structure of a battery cell assembly in one embodiment of the present application;

[0035] Fig.12 A structural diagram showing a battery cell and an insulating structure of a battery cell assembly in an embodiment of the present application assembled together;

[0036] Fig.13 This is a structural diagram of a battery cell assembly in an embodiment of the present application, in which a battery cell and an insulating structure are assembled together and fixed together by tape. DETAILED DESCRIPTION

[0037] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0038] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0040] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0041] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0042] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0043] like Figure 1 and Figure 2 As shown, the present application discloses a battery cell. The battery cell includes a battery cell assembly 10 and an electrolyte encapsulated in the battery cell assembly 10. Among them, the battery cell assembly 10 includes a shell 200 and a battery cell 300. The shell 200 has a circumferential wall 210 and a welding wall 220 arranged at the end of the circumferential wall 210. The battery cell 300 is arranged in the shell 200. The battery cell 300 includes a core body 310, an insulating film 320 and an electrode tab 330. The insulating film 320 is coated on the outside of the core body 310. The electrode tab 330 is convexly arranged at the end of the core body 310 corresponding to the welding wall 220 and passes out of the insulating film 320. The electrode tab 330 includes a welding portion 332 located between the welding wall 220 and the insulating film 320 and a tail portion 334 connected to the welding portion 332 and located between the circumferential wall 210 and the insulating film 320.

[0044] In the battery cell assembly of the related art, the electrode tabs 330 extending from the insulating film 320 are all located between the insulating film 320 and the welding wall 220. Due to the limited gap between the insulating film 320 and the welding wall 220, when the battery cell 300 is assembled into the housing 200, it is easy for the electrode tab 300 to be compressed and bent, causing the tail 334 of the electrode tab 300 to be inserted into the battery cell 300. Moreover, the welding surface formed after the electrode tab 330 and the welding wall 220 are welded will squeeze the electrode tab 300, and it is also easy for the electrode tab 300 to be compressed and bent, causing the tail 334 of the electrode tab 300 to be inserted into the battery cell 300. In addition, during subsequent transportation and use, when external force acts on the electrode tab 300 through the welding wall 220, it is also easy for the electrode tab 300 to be compressed and bent, causing the tail 334 of the electrode tab 300 to be inserted into the battery cell 300. In particular, when the battery cell 300 is a multi-tab battery cell (in this case, the electrode tab 300 includes multiple tabs), it is more likely that the electrode tab 300 is compressed and bent during assembly, welding, transportation and use, resulting in the tail 334 of the electrode tab 300 being inserted into the battery cell 300. If the electrode tab 300 inserted into the battery cell 300 contacts a pole piece with opposite electrical properties, it will cause a short circuit in the battery cell or even a fire.

[0045] In the above-mentioned battery cell assembly 10, the electrode tab 330 includes a welding portion 332 located between the welding wall 220 and the insulating film 320 and a tail portion 334 connected to the welding portion 332 and located between the circumferential wall 210 and the insulating film 320, that is, the electrode tab 330 extending from the insulating film 320 will "step back" toward the direction close to the circumferential wall 210 and extend between the circumferential wall 210 and the insulating film 320, so that the electrode tab 330 includes a welding portion 332 located between the welding wall 220 and the insulating film 320 and a tail portion 334 connected to the welding portion 332 and located between the circumferential wall 210 and the insulating film 320. The tail portion 334 of the electrode tab 330 is located between the circumferential wall 210 and the insulating film 320, which can effectively prevent the electrode tab 300 from being compressed and bent during assembly, welding, transportation and use, resulting in the tail portion 334 of the electrode tab 300 being inserted into the battery cell 300.

[0046] In some optional embodiments of the present application, the electrode tab 330 further includes an arc-shaped transition portion 336 connecting the welding portion 332 and the tail portion 334. In this way, the electrode tab 330 can be prevented from being damaged by the corner formed by the peripheral wall of the battery cell 300 and the end wall of the battery cell 300 close to the welding wall 220.

[0047] In some optional embodiments of the present application, such as Figure 2-Figure 4As shown, the battery cell assembly 10 also includes an insulating structure 400 located in the shell 200. The insulating structure 400 is sleeved outside one end of the battery cell 300 close to the welding wall 220. The insulating structure 400 includes a fixing portion 410 located between the welding wall 220 and the battery cell 300, and a connecting portion 420 connected to the fixing portion 410 and located between the circumferential wall 210 and the battery cell 300. The connecting portion 420 is connected to the battery cell 300. In this way, the insulating structure 400 can be provided on the battery cell 300 through the connecting portion 420, and the welding portion 332 can be fixed through the fixing portion 410 so that the welding portion 332 is fixed on one end of the battery cell 300 close to the welding wall 220, and when the insulating structure 400 is assembled on the battery cell 300, the connecting portion 420 can also be used as a force attachment point. It is understandable that in some optional embodiments, the insulating structure 400 may also be omitted, and in this case, the welding portion 332 may be bonded and fixed to one end of the battery cell 300 close to the welding wall 220 by using an adhesive tape.

[0048] In some optional embodiments of the present application, the material of the insulating structure 400 is PP (Polypropylene), so that the cost of the insulating structure 400 can be reduced.

[0049] In some optional embodiments of the present application, the thickness of the insulating structure 400 is 0.5-0.9 mm. In this way, not only can the insulating structure 400 have a certain structural strength, but also the space occupied by the insulating structure 400 in the housing 200 can be reduced, which is conducive to providing the energy density of the battery cell assembly 10. In some optional embodiments of the present application, the thickness of the insulating structure 400 is 0.7 mm.

[0050] In some optional embodiments of the present application, the connecting portion 420 is arranged perpendicular to the plane where the fixing portion 410 is located. In this way, it is easier for the connecting portion 420 and the fixing portion 410 to fit the peripheral wall of the battery cell 300 and the end wall of the battery cell close to the welding wall 220 respectively.

[0051] In some optional embodiments of the present application, the fixing portion 410 has a welding through hole 412. The welding portion 332 is welded to the welding wall 220 through the welding through hole 412. In this way, it is very convenient to electrically connect the welding portion 332 to the welding wall 220. It can be understood that in some optional embodiments, the welding through hole 412 can be omitted. In this case, the electrical connection can be achieved by welding the tail portion 334 to the circumferential wall 210.

[0052] In some optional embodiments of the present application, the connection part 420 is connected to the battery cell 300 by gluing. In this way, it is very convenient to set the insulating structure 400 on the battery cell 300 through the connection part 420. It can be understood that in some optional embodiments, the connection part 420 can also be set on the battery cell 300 by other methods such as hot melting. In some optional embodiments of the present application, the battery cell assembly 10 also includes a tape 500 located outside the connection part 420. The tape 500 covers at least part of the connection part 420 to bond with the connection part 420, and at least part of the tape 500 protrudes outside the connection part 420 and bonds with the battery cell 300. It can be understood that in some optional embodiments, the tape 500 can also be located between the connection part 420 and the battery cell 300.

[0053] In some optional embodiments of the present application, the connecting portion 420 has a notch 422 for exposing the tail 334 of the electrode tab 300 outside the connecting portion 420. In this way, the weight of the connecting portion 420 can be reduced. It can be understood that in some optional embodiments, the notch 422 can be omitted. In this case, the connecting portion 420 can be a closed loop structure, and the connecting portion 420 can be sleeved on the end of the battery cell 300 close to the welding wall 220 through the opening on the side away from the fixing portion 410, so that the tail 334 is located between the battery cell 300 and the connecting portion 420, and the connecting portion 420 can fix the tail 334.

[0054] In some optional embodiments of the present application, the fixing portion 410 extends from the notch 422 to between the battery cell 300 and the circumferential wall 210 to form a limiting portion 414 located between the battery cell 300 and the circumferential wall 210 for limiting the tail portion 334. Figure 2 Taking the perspective shown in the figure as an example, the direction is from top to bottom), when the battery cell 300 equipped with the insulating structure 400 is inserted into the shell 200, the limiting portion 414 can limit the tail portion 334, and even if the tail portion 334 is not bent and fixed in the circumferential direction of the battery cell 300 in advance, the tail portion 334 can smoothly enter between the battery cell 300 and the circumferential wall 210. Moreover, the limiting portion 414 can also ensure that the electrode tab 330 transitions in an arc shape and forms an arc transition portion 336 connecting the welding portion 332 and the tail portion 334. It can be understood that in some optional embodiments, the limiting portion 414 can also be omitted. In this case, before the battery cell 300 equipped with the insulating structure 400 is inserted into the shell 200, the tail portion 334 can be bent and fixed in the circumferential direction of the battery cell 300 using tape.

[0055] In some optional embodiments of the present application, the notch 422 extends from the side of the connecting portion 420 away from the fixing portion 410 to the fixing portion 410. The insulating structure 400 can be sleeved on the end of the battery cell 300 close to the welding wall 220 through the notch 422 (with Fig.11Taking the perspective shown as an example, the notch 422 is located on the right side of the connecting portion 420, and the insulating structure 400 can be sleeved from left to right on the end of the battery cell 300 close to the welding wall 220 through the notch 422). In this way, when the insulating structure 400 is sleeved on the battery cell 300 through the notch 422, the fixing portion 410 can guide the electrode tab 330 extending from the insulating film 320 toward the direction close to the circumferential wall 210, which is not only convenient for forming the welding portion 332 but also very convenient for fixing the position of the welding portion 332, so as to facilitate automated assembly (no need to manually control the electrode tab 330 to move toward the direction close to the circumferential wall 210 to form the welding portion 332). It should be noted that the fact that the insulating structure 400 can be sleeved on the end of the battery cell 300 close to the welding wall 220 through the notch 422 indicates that the size of the notch 422 is larger than the size of the battery cell 300. For example, when the battery cell 300 is cylindrical, the opening width d of the notch 422 is larger than the diameter of the battery cell 300. Similarly, the battery cell 300 equipped with the insulating structure 400 needs to be installed in the housing 200 , which means that the outer dimension of the insulating structure 400 is smaller than the inner dimension of the housing 200 .

[0056] In some optional embodiments of the present application, such as Figure 5 and Figure 6 As shown, in the circumferential direction of the connecting portion 420, the connecting lines ( Figure 6 The fixing portion 410 is divided into a first portion 410a connected to the connecting portion 420 and a second portion 410b connected to the first portion 410a by the dotted line in FIG. 4 . The limiting portion 414 is located at the end of the second portion 410b away from the first portion 410a. At this time, the insulating structure 400 is generally L-shaped. In some optional embodiments of the present application, the width of the second portion 410b gradually decreases in the direction away from the first portion 410a. In this way, the weight of the fixing portion 410 can be reduced.

[0057] In some optional embodiments of the present application, the second portion 410b includes a plurality of arc segments. Figure 3 and Figure 4 As shown, the second portion 410b includes two arc segments, namely a first arc segment and a second arc segment. The first portion 410a, the first arc segment and the second arc segment are connected in sequence. The radius of the first arc segment is greater than the radius of the second arc segment. In some optional embodiments of the present application, such as Figure 5 and Figure 6 As shown, the second portion 410b includes a circular arc segment and a wedge-shaped segment. The first portion 410a, the circular arc segment and the wedge-shaped segment are connected in sequence.

[0058] In some optional embodiments of the present application, such as Figure 7-10As shown, the side of the connecting portion 420 away from the welding wall 220 has at least one recessed groove 424. In this way, the weight of the connecting portion 420 can be reduced. In some optional embodiments of the present application, such as Figure 7 and Figure 8 As shown, the side of the connecting portion 420 away from the welding wall 220 has two inward grooves 424. In some optional embodiments of the present application, as Fig. 9 and Fig.10 As shown, the connecting portion 420 has three inward grooves 424 on a side away from the welding wall 220 .

[0059] In some optional embodiments of the present application, such as Figure 1 and Figure 2 As shown, the housing 200 further includes a pole wall 230 disposed at the other end of the circumferential wall 210. A pole 240 insulated from the pole wall 230 is disposed on the pole wall 230. The battery cell 300 further includes a pole tab 340. The pole tab 340 is protruding from the end of the core body 310 corresponding to the pole wall 230 and passes through the insulating film 320. The pole tab 340 is welded to the pole 240 and electrically connected. Among them, one of the electrode tab 330 and the pole tab 340 is a positive pole tab, and the other is a negative pole tab.

[0060] In some optional embodiments of the present application, the battery cell assembly 10 is a battery cell assembly 10 of a cylindrical battery, and the shell 200 and the battery cell 300 are both cylindrical. Among them, the shell 200 is a steel shell, the electrode tab 330 is a negative electrode tab, the pole tab 340 is a positive electrode tab, and the connecting portion 420 is an arc plate.

[0061] Combine the following Figure 2 and attached Figure 11-13 The assembly method of the battery cell assembly 10 is described as follows:

[0062] (1) Figure 2 and Fig.11 As shown, the pole wall 230 is first assembled on the core 310, and laser welding is used to weld the pole ear 340 on the core 310 to the pole 240 to achieve electrical connection.

[0063] (2) The core 310 is covered with an insulating film 320 , and the pole tab 340 and the electrode tab 330 are exposed outside the insulating film 320 .

[0064] (3) Figure 2 and Fig.12As shown, the insulating structure 400 is placed parallel to one side of the battery cell 300, and then the insulating structure 400 is controlled to translate toward the battery cell 300. The insulating structure 400 is sleeved outside one end of the battery cell 300 close to the welding wall 220 through the notch 422. At the same time, the electrode tab 330 is "backward" toward the moving direction of the insulating structure 400 under the guidance of the fixing portion 410. The middle part of the electrode tab 330 is clamped between the fixing portion 410 and the battery cell 300 to form a welding portion 332, and the tail 334 of the electrode tab 330 protrudes out of the battery cell 300. Before performing step (3), the electrode tab 330 can be artificially bent and the welding portion 332 can be pre-fixed on the end wall of the battery cell 300 close to the welding wall 220, and the tail 334 of the electrode tab 330 can protrude out of the battery cell 300. On this basis, the tail portion 334 protruding out of the battery cell 300 may be artificially bent and the tail portion 334 may be pre-fixed on the circumferential wall of the battery cell 300 .

[0065] (4) Figure 2 and Fig.13 As shown, the adhesive tape 500 is used to connect the connecting portion 420 and the battery cell 300 , so that the insulating structure 400 is fixed on the battery cell 300 .

[0066] (5) The battery cell 300 equipped with the insulating structure 400 is inserted into the housing 200. During the insertion process, the limiting portion 414 of the fixing portion 410 limits the tail portion 334 protruding out of the battery cell 300, and allows the tail portion 334 to smoothly enter between the battery cell 300 and the circumferential wall 210.

[0067] (6) The welding portion 332 is welded to the welding wall 210 to achieve electrical connection, and the circumferential wall 210 of the housing 200 is connected to the pole wall 230 to obtain an assembled battery cell assembly 10.

[0068] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A battery cell assembly, characterized in that: include: A shell having a circumferential wall and a welding wall provided at an end of the circumferential wall; as well as A battery cell is arranged in the shell, and the battery cell includes a core body, an insulating film and an electrode tab. The insulating film is coated on the outside of the core body, and the electrode tab is protruded at the end of the core body corresponding to the welding wall and passes through the outside of the insulating film. The electrode tab includes a welding portion located between the welding wall and the insulating film and a tail portion connected to the welding portion and located between the circumferential wall and the insulating film.

2. The battery cell assembly according to claim 1, characterized in that: The electrode tab also includes an arc-shaped transition portion connecting the welding portion and the tail portion.

3. The battery cell assembly according to claim 1, characterized in that: It also includes an insulating structure located in the shell, the insulating structure is sleeved outside one end of the battery cell close to the welding wall, the insulating structure includes a fixing portion located between the welding wall and the battery cell and a connecting portion connected to the fixing portion and located between the circumferential wall and the battery cell, and the connecting portion is connected to the battery cell.

4. The battery cell assembly according to claim 3, characterized in that: The insulating structure is made of polypropylene; and / or The thickness of the insulating structure is 0.5-0.9 mm; and / or The connecting portion is arranged perpendicular to the surface where the fixing portion is located; and / or The connecting portion has at least one recessed groove on a side away from the fixing portion; and / or The fixing portion has a welding through hole, and the welding portion is welded to the welding wall through the welding through hole; and / or The connecting portion is connected to the battery core by gluing.

5. The battery cell assembly according to claim 3, characterized in that: The connecting portion has a notch for exposing the tail portion outside the connecting portion.

6. The battery cell assembly according to claim 5, characterized in that: The fixing portion extends from the notch to between the battery core and the circumferential wall to form a limiting portion located between the battery core and the circumferential wall for limiting the tail portion.

7. The battery cell assembly according to claim 5, characterized in that: The notch extends from a side of the connecting portion away from the fixing portion to the fixing portion, and the insulating structure can be sleeved outside an end of the battery core close to the welding wall through the notch.

8. The battery cell assembly according to claim 5, characterized in that: In the circumferential direction of the connecting portion, connecting lines at both ends of the connecting portion divide the fixing portion into a first portion connected to the connecting portion and a second portion connected to the first portion, and the width of the second portion gradually decreases in a direction away from the first portion.

9. The battery cell assembly according to claim 1, characterized in that: The shell further comprises a pole wall provided at the other end of the circumferential wall, the pole wall being provided with a pole insulated from the pole wall, the battery core further comprises a pole ear, the pole ear protruding at the end of the core body corresponding to the pole wall and passing through the insulating film, the pole ear being welded and electrically connected to the pole, one of the electrode ear and the pole ear being a positive pole ear, and the other being a negative pole ear; and / or The shell and the battery core are both cylindrical.

10. A battery cell, characterized in that: Comprising a battery core assembly as described in any one of claims 1 to 9.

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