Battery cell components and electrical devices

Abstract

The present application discloses a battery cell assembly and an electrical device. The battery cell assembly includes a shell, an electrode terminal and an electrode assembly. The shell includes a first side wall and a second side wall arranged relatively spaced apart in the thickness direction of the shell, and the first side wall is provided with a recessed portion facing away from the second side wall on the side facing the second side wall; the electrode terminal is led out from the shell; the electrode assembly is accommodated in the shell, the electrode assembly and the electrode terminal are arranged relatively in a first direction, and the electrode assembly includes a pole ear connected to the electrode terminal, the pole ear is at least partially bent into an arc, and the projection of the pole ear bent into an arc in the thickness direction at least partially falls in the recessed portion, and the thickness direction is arranged to intersect with the first direction. The battery cell assembly provided by the present application improves the volume energy density.

Description

Technical Field

[0001] The present application relates to the technical field of electric energy storage, and in particular to a battery cell assembly and an electric device. Background Art

[0002] A battery cell assembly is a device that converts external energy into electrical energy and stores it inside, so as to power external electrical devices (such as portable electronic devices, etc.) when needed. In order to meet the requirements of thin product design, the thickness of battery cell assemblies is getting thinner and thinner. In the battery cell assemblies of the related technology, the pole ears need to be led out of the shell through the electrode terminals. When the thickness of the battery cell assembly is sufficient, the pole ears can be bent so that the pole ears occupy a smaller space and are connected to the electronic terminals; when the thickness of the battery cell assembly is insufficient, the thickness of the battery cell assembly is not enough for the pole ears to bend, so that a larger space needs to be reserved in the battery cell assembly to place the straight pole ears, resulting in a loss of volume energy density.

[0003] In summary, it is necessary to design a battery cell assembly and an electrical device to solve the above technical problems. Summary of the invention

[0004] The embodiments of the present application provide a battery cell assembly and an electrical device, wherein the volume energy density of the battery cell assembly is improved.

[0005] In a first aspect, an embodiment of the present application provides a battery cell assembly, including:

[0006] The shell comprises a first side wall and a second side wall which are arranged relatively spaced apart in a thickness direction of the shell, wherein a concave portion which is concave away from the second side wall is provided on a side of the first side wall facing the second side wall;

[0007] Electrode terminals, led out from the shell;

[0008] An electrode assembly is housed in a shell, wherein the electrode assembly and the electrode terminal are arranged relative to each other along a first direction, the electrode assembly includes a pole ear connected to the electrode terminal, the pole ear includes a bending portion, a projection of a portion of the bending portion along the thickness direction at least partially falls on the recess, and the thickness direction is arranged to intersect with the first direction.

[0009] In some embodiments, the electrode assembly includes a first electrode sheet and a second electrode sheet alternately stacked in a thickness direction, and a separator disposed between the first electrode sheet and the second electrode sheet.

[0010] There are multiple pole tabs, and the first pole piece and the second pole piece are respectively connected to the multiple pole tabs in a one-to-one correspondence.

[0011] In some embodiments, the pole ear includes a first extension portion, a second extension portion, a bending portion and a third extension portion, the first extension portion is connected to the first pole piece or the second pole piece along a first direction, the second extension portion extends from the first extension portion in a direction away from the second side wall, the third extension portion and the second extension portion are spaced apart along the first direction, the bending portion is at least partially bent into an arc shape and connects the second extension portion and the third extension portion, and at least part of the bending portion is accommodated in the recess.

[0012] In some embodiments, the recess is a groove extending along the second direction, and the thickness direction, the first direction, and the second direction are perpendicular to each other.

[0013] In some embodiments, the shell also includes a connecting wall and an extension wall, the connecting wall is arranged around the first side wall and connects the first side wall and the extension wall, the peripheral side of the second side wall is sealed with the extension wall, and the two ends of the recess along the first direction are respectively connected to the first side wall and the connecting wall.

[0014] In some embodiments, two ends of the recess along the second direction are respectively connected to the connecting walls.

[0015] In some embodiments, of the two ends of the recess along the second direction, one end is connected to the first side wall, and the other end is connected to the connecting wall.

[0016] In some embodiments, two ends of the recess along the second direction are respectively connected to the first side wall.

[0017] In some embodiments, the electrode tab includes a first electrode tab connected to the first electrode piece, and a second electrode tab connected to the second electrode piece; the electrode terminal includes a first terminal connected to the first electrode tab, and a second terminal connected to the second electrode tab;

[0018] The number of the recesses is two, and the two recesses are arranged at intervals along the first direction. The bent portion of the first pole tab is arranged in one of the recesses, and the bent portion of the second pole tab is arranged in the other recess.

[0019] In some embodiments, the minimum width of the recess along the first direction is W1, the minimum distance from the side of the first pole piece close to the electrode terminal to the connecting wall along the first direction is W2, and W2>W1>1.2 mm.

[0020] In some embodiments, the maximum spacing distance between the first sidewall and the second sidewall is H1, and the maximum spacing distance between the recess and the second sidewall is H2, H1<H2, H2≥2.0 mm.

[0021] In a second aspect, an embodiment of the present application further provides an electrical device, comprising a battery cell assembly provided according to the second aspect, wherein the battery cell assembly is used to provide electrical energy.

[0022] In some embodiments, the electrical device includes a housing, the housing includes a receiving space and an escape space that are connected, the battery cell assembly is partially engaged in the receiving space, and the recess is engaged in the escape space.

[0023] Compared with the related art, in the battery cell assembly and the electrical device provided in the embodiments of the present application, a recess is provided in the shell, and the projection of the pole ear bent into an arc along the thickness direction is at least partially located in the recess, so that when there is a small gap between the first side wall and the second side wall, a larger space can be provided between the recess and the second side wall for the bending of the pole ear, eliminating the need to reserve a large space for placing the straight-extending pole ear, thereby improving the volume energy density of the battery cell assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application 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 creative work.

[0025] Figure 1 It is a schematic diagram of the exploded structure of a battery cell assembly provided in one embodiment of the present application;

[0026] Figure 2 yes Figure 1 An enlarged structural schematic diagram of part A is shown;

[0027] Figure 3 It is a schematic diagram of the three-dimensional structure of a battery cell assembly provided in one embodiment of the present application;

[0028] Figure 4 is along Figure 3 A schematic diagram of a partial cross-sectional structure of line BB shown;

[0029] Figure 5 It is a schematic diagram of a partial cross-sectional structure of a battery cell assembly provided in one embodiment of the present application;

[0030] Figure 6 It is a schematic diagram of the three-dimensional structure of a battery cell assembly provided in one embodiment of the present application;

[0031] Figure 7 yes Figure 6 An enlarged schematic diagram of the structure of part C is shown;

[0032] Figure 8 It is a schematic diagram of the three-dimensional structure of a battery cell assembly provided in one embodiment of the present application;

[0033] Fig. 9 It is a schematic diagram of the cross-sectional structure of an electrical device provided in one embodiment of the present application.

[0034] In the attached figure:

[0035] 10. Cell assembly; 1. Shell; 11. First side wall; 12. Second side wall; 13. Recess; 14. Connecting wall; 15. Extension wall; 2. Electrode terminal; 21. First terminal; 22. Second terminal; 3. Electrode assembly; 31. Tab; 311. First extension; 312. Second extension; 313. Bend; 314. Third extension; 32. First pole piece; 33. Second pole piece; 34. Isolation film;

[0036] X, thickness direction; Y, first direction; Z, second direction;

[0037] 20. Shell; 201. Accommodation space; 202. Avoidance space; 30. Control module. DETAILED DESCRIPTION

[0038] The features and exemplary embodiments of various aspects of the application will be described in detail below. In the detailed description below, many specific details are proposed to provide a comprehensive understanding of the application. However, it is obvious to those skilled in the art that the application can be implemented when some details in these specific details are not needed. The following description of the embodiments is only to provide a better understanding of the application by illustrating the example of the application.

[0039] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The embodiments will be described in detail below in conjunction with the accompanying drawings.

[0040] In order to better understand the technical solution and technical effects of the present application, the following will describe specific embodiments in detail with reference to the accompanying drawings.

[0041] See also Figure 1 , Figure 2 , Figure 3 and Figure 4 A battery cell assembly 10 includes a shell 1, an electrode terminal 2 and an electrode assembly 3, the shell 1 includes a first side wall 11 and a second side wall 12 arranged relatively and spaced apart along a thickness direction X, and a recess is provided on the first side wall surface 11 facing the second side wall 12; the electrode terminal 2 is led out from the shell 1; the electrode assembly 3 is accommodated in the shell 1, the electrode assembly 3 and the electrode terminal 2 are arranged relatively along a first direction Y, the electrode assembly 3 includes a pole ear 31 connected to the electrode terminal 2, the pole ear 31 is at least partially bent into an arc shape, and the projection of the portion of the pole ear 31 bent into an arc shape along the thickness direction X at least partially falls on the recess 13, and the thickness direction X is arranged to intersect with the first direction Y.

[0042] The battery cell assembly 10 provided in the present application can specifically be a lithium-ion secondary battery cell assembly, a lithium-ion primary battery cell assembly, a lithium-sulfur battery cell assembly, a sodium-lithium-ion battery cell assembly, a sodium-ion battery cell assembly or a magnesium-ion battery cell assembly, etc., and the embodiments of the present application are not limited to this.

[0043] The shell 1 may be an aluminum-plastic film. In addition to the tab 31, the electrode assembly 3 also includes a positive electrode sheet, a negative electrode sheet and a separator 34. The portion of the electrode assembly 3 having active substances constitutes the positive electrode sheet and the negative electrode sheet of the electrode assembly 3, and the portion without active substances constitutes the tab 31. In addition to the shell 1, the electrode terminal 2 and the electrode assembly 3, the battery cell assembly 10 also has an electrolyte contained in the shell 1, and the positive electrode sheet, the negative electrode sheet and the separator 34 are immersed in the electrolyte. In some embodiments, the positive electrode sheet, the negative electrode sheet and the separator 34 are wound to form a winding structure. In other embodiments, the positive electrode sheet, the separator 34 and the negative electrode sheet are stacked in sequence to form a laminated structure. Those skilled in the art can select a suitable electrode assembly 3 as needed. During the charge and discharge process of the battery cell assembly 10, the positive active substance and the negative active substance react with the electrolyte. The tab 31 is used to connect the electrode terminal 2 to form a current loop.

[0044] The electrode terminal 2 also includes a first terminal 21 and a second terminal 22 that are electrically connected to the positive electrode sheet and the negative electrode sheet, respectively. Of course, the first terminal 21 and the second terminal 22 need to be spaced apart to avoid contact between the two and cause a short circuit. The first terminal 21 and the second terminal 22 can be led out from the same end of the shell 1, and the first terminal 21 and the second terminal 22 can also be led out from the opposite ends of the shell 1 along the first direction Y. In another embodiment, the electrode terminal 2 is led out from the first end of the shell 1, and the recess 13 is provided at the first end of the shell 1, so that the pole ear 31 can be directly connected to the electrode terminal 2 after being bent between the recess 13 and the second side wall 12, which facilitates the connection between the pole ear 31 and the electrode terminal 2. Optionally, the first direction Y is the length direction of the battery cell assembly 10, the electrode terminal 2 is led out along the length direction of the battery cell assembly 10, and the first end is one end of the shell 1 along the length direction.

[0045] The housing 1 includes a first side wall 11 and a second side wall 12 that are arranged opposite to each other along the thickness direction X. The positive electrode sheet, the negative electrode sheet and the separator 34 in the electrode assembly 3 can be stacked along the thickness direction X and accommodated between the first side wall 11 and the second side wall 12. The first side wall 11 and the second side wall 12 can maintain a relatively flat surface to facilitate the application of the battery cell assembly 10 in the power setting. The first side wall 11 can be thinned to form a recess 13, and of course, it can also extend outward from the first side wall 11 away from the second side wall 12 to form the recess 13. It can be understood that the recess 13 is recessed relative to the plane where the first side wall 11 is located along the thickness direction X away from the second side wall 12. The recess provides a certain accommodation space, that is, compared with the gap between the first side wall 11 and the second side wall 12, there is a larger gap between the recess 13 and the second side wall 12. The pole ear 31 can be bent and then connected to the electrode terminal 2, and can be bent between the recess 13 and the second side wall 12. The recessed portion 13 ensures that the housing 1 provides a suitable space for the tab 31 to bend.

[0046] In this embodiment, a recess 13 is provided in the shell 1, and the projection of the arc-shaped portion of the pole ear 31 along the thickness direction X is set to at least partially fall on the recess 13, so that there is a small gap between the first side wall 11 and the second side wall 12. A larger space can be provided between the recess 13 and the second side wall 12 for bending the pole ear 31, eliminating the need to reserve a large space for placing the straight-extending pole ear 31, thereby improving the volume energy density of the battery cell assembly 10.

[0047] See also Figure 3 and Figure 4 In some embodiments, the electrode assembly 3 is a laminated structure. The electrode assembly 3 includes a first pole piece 32 and a second pole piece 33 alternately stacked along the thickness direction X, and a separation film 34 disposed between the first pole piece 32 and the second pole piece 33. There are multiple pole tabs 31, and the first pole piece 32 and the second pole piece 33 are respectively connected to the multiple pole tabs 31 in a one-to-one correspondence.

[0048] One of the first pole piece 32 and the second pole piece 33 is a cathode pole piece, and the other is an anode pole piece. Each first pole piece 32 and each second pole piece 33 are connected to a corresponding pole ear 31, and then electrically connected to the electrode terminal 2 through the pole ear 31. Optionally, each pole ear 31 extends from the pole piece along the length direction of the battery cell assembly 10, and between the recess 13 and the second side wall 12, the pole ear 31 is bent and multiple pole pieces are stacked into a sheet structure, so that it is convenient for the electrode terminal 2 to be directly connected to the sheet structure.

[0049] In some embodiments, the pole ear 31 includes a first extension portion 311, a second extension portion 312, a bending portion 313 and a third extension portion 314. The first extension portion 311 is connected to the first pole piece 32 or the second pole piece 33 along the first direction Y, the second extension portion 312 extends from the first extension portion 311 in a direction away from the second side wall 12, the third extension portion 314 and the second extension portion 312 are spaced apart along the first direction Y, the bending portion 313 is at least partially bent into an arc shape and connects the second extension portion 312 and the third extension portion 314, and at least part of the bending portion 313 is accommodated in the recess 13.

[0050] The pole lug 31 can be bent multiple times between the second side wall 12 and the recess 13. Optionally, the first extension portion 311 extends between the second side wall 12 and the recess 13 along the first direction Y, the second extension portion 312 performs the first bending of the pole lug 31 between the second side wall 12 and the recess 13, the second extension portion 312 extends to the bending portion 313 away from the second side wall 12, the bending portion 313 performs the second bending of the pole lug 31 in the recess 13 and connects the second extension portion 312 and the third extension portion 314, and the third extension portion 314 extends toward the second side wall 12. The second extension portions 312 of the plurality of pole lugs 31 are stacked into a sheet structure between the second side wall 12 and the recess 13. By providing the recess 13, a larger gap can be provided between the second side wall 12 and the recess 13 for the second extension portion 312 and the bending portion 313 to extend.

[0051] In some embodiments, the recess 13 is a groove extending along the second direction Z, and the thickness direction X, the first direction Y and the second direction Z are perpendicular to each other.

[0052] Since the tab 31 is a sheet structure, the recess 13 is set as a groove extending along the second direction Z, so that a gap can be provided between the recess 13 and the second side wall 12 for the tab 31 to bend along the second direction Z. The second direction Z can be the width direction of the battery cell assembly 10.

[0053] In some embodiments, the shell 1 also includes a connecting wall 14 and an extension wall 15, the connecting wall 14 is arranged around the first side wall 11 and connects the first side wall 11 and the extension wall 15, the peripheral side of the second side wall 12 is tightly connected to the extension wall 15, and the two ends of the recess 13 along the first direction Y are respectively connected to the first side wall 11 and the connecting wall 14.

[0054] The connecting wall 14 can extend from the first side wall 11 along the thickness direction X toward the second side wall 12, and one end of the recess 13 along the first direction Y is connected to the connecting wall 14, that is, the recess 13 is arranged at the edge of the first side wall 11. The extension wall 15 extends outward from the connecting wall 14, and the peripheral side of the second side wall 12 overlaps with the extension wall 15 and is sealed and connected to form a receiving space 201 covering the electrode assembly 3. Optionally, the second side wall 12 and the extension wall 15 are sealed and connected along the thickness direction X. Optionally, the electrode terminal 2 extends out of the housing 1 from between the second side wall 12 and the extension wall 15.

[0055] The concave portion 13 may be a groove extending along the second direction Z, and the groove bottom wall of the concave portion 13 may be an arc surface or a flat bottom. When the groove bottom wall of the concave portion 13 is an arc surface, the groove side wall on one side of the concave portion 13 is extended along the first side wall 11 in a direction away from the second side wall 12, the groove side wall is bent to form an arc surface groove bottom wall, and the groove bottom wall is extended from the groove bottom wall in a direction close to the second side wall 12 until it is connected with the connecting wall 14 to form the groove side wall on the other side of the concave portion 13.

[0056] In some embodiments, both ends of the recess 13 along the second direction Z are respectively connected to the connecting walls 14. That is, the length of the recess 13 along the second direction Z is consistent with the spacing distance between the connecting walls 14 spaced apart along the second direction Z. The recess 13 has a relatively long length, and both the anode tab and the cathode tab can be spaced apart and placed in the recess 13.

[0057] See also Figure 5 and Figure 6 In other embodiments, one end of the two ends of the recess 13 along the second direction Z is connected to the first side wall 11, and the other end is connected to the connecting wall 14. In another embodiment, the two ends of the recess 13 along the second direction Z are respectively connected to the first side wall 11. Compared with the case where both ends of the recess 13 along the second direction Z are connected to the connecting wall 14, when at least one end of the two ends of the recess 13 along the second direction Z is connected to the first side wall 11, the recess 13 has a shorter length along the second direction Z, so that the battery cell assembly 10 has a smaller volume.

[0058] See also Figure 7 In other embodiments, the electrode tab 31 includes a first electrode tab connected to the first electrode piece 32 and a second electrode tab connected to the second electrode piece 33; the electrode terminal 2 includes a first terminal 21 connected to the first electrode tab and a second terminal 22 connected to the second electrode tab;

[0059] There are two recesses 13 , which are spaced apart along the first direction Y. The first pole tab is bent into an arc shape in one recess 13 , and the second pole tab is bent into an arc shape in the other recess 13 .

[0060] One of the first electrode tab and the second electrode tab is an anode electrode tab and the other is a cathode electrode tab, respectively placed in two recesses 13. By providing two recesses 13 spaced apart, the first electrode tab and the second electrode tab can be bent in different recesses 13, respectively.

[0061] See also Figure 8 In some embodiments, the minimum width of the recess 13 along the first direction Y is W1, and the minimum distance from the side of the first pole piece 32 close to the electrode terminal 2 to the connecting wall 14 along the first direction Y is W2, W2>W1>1.2mm.

[0062] The first pole piece 32 may be a cathode pole piece. W2>W1, that is, the first pole piece 32 is disposed between the first side wall 11 and the second side wall 12, and does not extend between the recess 13 and the second side wall 12, so as to avoid the bent pole piece from contacting the first pole piece 32. The minimum distance from the side of the first pole piece 32 close to the electrode terminal 2 along the first direction Y to the connecting wall 14 is W3. In order to ensure the performance of the first pole piece 32 and the second pole piece 33, the HIA may set W3>W1>1.2mm.

[0063] W1>1.2mm, that is, the distance from one end of the recess 13 connected to the first side wall 11 to one end connected to the connecting wall 14 along the first direction Y is greater than 1.2mm, so that the radius of the bending portion 313 bent into an arc can reach 0.6mm.

[0064] In some embodiments, the maximum spacing distance between the first side wall 11 and the second side wall 12 is H1, and the maximum spacing distance between the recess 13 and the second side wall 12 is H2, H1<H2, H2≥2.0mm. When H2≥2.0mm, the electrode can be bent without breaking. The thickness of the battery cell assembly 10 along the thickness direction is H0, H0≤3.0mm, so as to ensure that the battery cell assembly 10 has a thin thickness.

[0065] In one embodiment, H0=1.8mm, H1=1.55mm, H2=2.5mm, W1=1.4mm, W2=2.3mm, the tab is connected to the electrode terminal after being bent twice, the maximum distance from the plane where the first extension portion is located to the bending portion is the bending height H, and the bending height H=2.4mm.

[0066] In one embodiment, H0=2.5mm, H1=2.34mm, H2=2.8mm, W1=1.6mm, W2=2.5mm, the tab is connected to the electrode terminal after being bent twice, the maximum distance from the plane where the first extension portion is located to the bending portion is the bending height H, and the bending height H=2.6mm.

[0067] In one embodiment, H0=1.5mm, H1=1.3mm, H2=2.35mm, W1=1.3mm, W2=2.1mm, the tab is connected to the electrode terminal after being bent twice, the maximum distance from the plane where the first extension portion is located to the bending portion is the bending height H, and the bending height H=2.05mm.

[0068] In the second aspect, the present application also provides an electrical device, see Fig. 9 The electrical device includes the battery cell assembly 10 provided in the first aspect, and the battery cell assembly 10 is used to provide electrical energy.

[0069] There can be multiple battery cell assemblies 10 , which can be connected in series, in parallel, or in mixed connection to form a whole, through which charging and discharging are performed externally, wherein mixed connection means that multiple battery cell assemblies 10 are connected in series or in parallel.

[0070] Specific product types of electrical devices include but are not limited to mobile terminals, smart wearables, power tools, electric vehicles, mobile power supplies, etc.

[0071] Since the battery cell assembly 10 has the aforementioned beneficial effects, the electrical device has higher safety and reliability and a longer service life.

[0072] In one embodiment, the electrical device includes a housing 20 , the housing 20 includes a receiving space 201 and an escape space 202 that are connected to each other, the battery cell assembly 10 is partially engaged in the receiving space 201 , and the recess 13 is engaged in the escape space 202 .

[0073] By providing the escape space 202 in the housing 20, the housing 1 with the recess 13 can be engaged in the escape space 202, ensuring that the housing 20 and the battery cell assembly 10 are tightly assembled. The electrical device may further include a control module 30 provided in the receiving space 201, and the electrode terminal 2 is connected to the control module 30.

[0074] In addition, the term "and / or" in this article is only a description of the association relationship between the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0075] It should be understood that in the embodiment of the present application, "B corresponding to A" means that B is associated with A, and B can be determined according to A. However, it should also be understood that determining B according to A does not mean determining B only according to A, and B can also be determined according to A and / or other information.

[0076] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A battery cell assembly, characterized in that: include: The shell comprises a first side wall and a second side wall which are arranged relatively spaced apart in a thickness direction of the shell, wherein a concave portion which is concave in a direction away from the second side wall is provided on a side of the first side wall facing the second side wall; An electrode terminal is led out from the housing; An electrode assembly is accommodated in the shell, the electrode assembly and the electrode terminal are arranged opposite to each other along a first direction, the electrode assembly includes a pole ear connected to the electrode terminal, a first pole piece and a second pole piece connected to the pole ear, the pole ear includes a bending portion, the projection of the bending portion along the thickness direction at least partially falls on the recessed portion, and the thickness direction is arranged to intersect with the first direction.

2. The battery cell assembly according to claim 1, characterized in that: The electrode assembly includes a separation film disposed between the first pole piece and the second pole piece, and the first pole piece and the second pole piece are alternately stacked along the thickness direction. There are multiple pole tabs, and the first pole piece and the second pole piece are respectively connected to the multiple pole tabs in a one-to-one correspondence.

3. The battery cell assembly according to claim 2, characterized in that: The pole ear also includes a first extension portion, a second extension portion and a third extension portion, the first extension portion is connected to the first pole piece or the second pole piece along the first direction, the second extension portion extends from the first extension portion in a direction away from the second side wall, the third extension portion and the second extension portion are spaced apart along the first direction, the bent portion is at least partially bent into an arc shape and connects the second extension portion and the third extension portion, and at least part of the bent portion is accommodated in the recess.

4. The battery cell assembly according to claim 2, characterized in that: The concave portion is a groove extending along the second direction, and the thickness direction, the first direction and the second direction are perpendicular to each other.

5. The battery cell assembly according to claim 4, characterized in that: The shell also includes a connecting wall and an extension wall. The connecting wall is arranged around the first side wall and connects the first side wall and the extension wall. The peripheral side of the second side wall is tightly connected to the extension wall. One end of the recess along the first direction is connected to the connecting wall.

6. The battery cell assembly according to claim 5, characterized in that: Two ends of the recess along the second direction are respectively connected to the connecting walls.

7. The battery cell assembly according to claim 5, characterized in that: Of the two ends of the recess along the second direction, one end is connected to the first side wall, and the other end is connected to the connecting wall.

8. The battery cell assembly according to claim 5, characterized in that: Two ends of the recess along the second direction are respectively connected to the first side wall.

9. The battery core assembly according to claim 7 or 8, characterized in that: The plurality of pole tabs include a first pole tab connected to the first pole piece, and a second pole tab connected to the second pole piece; the electrode terminal includes a first terminal connected to the first pole tab, and a second terminal connected to the second pole tab; The number of the recesses is two, and the two recesses are arranged at intervals along the first direction. The bent portion of the first pole tab is arranged in one of the recesses, and the bent portion of the second pole tab is arranged in the other recess.

10. The battery core assembly according to claim 5, characterized in that: The minimum width of the recess along the first direction is W1, and the minimum distance from the side of the first pole piece close to the electrode terminal to the connecting wall along the first direction is W2, where W2>W1>1.2 mm.

11. The battery core assembly according to claim 1, characterized in that: The maximum spacing distance between the first side wall and the second side wall is H1, and the maximum spacing distance between the recess and the second side wall is H2, H1<H2, H2≥2.0 mm.

12. An electrical device, characterized in that: The invention comprises a battery cell assembly according to any one of claims 1 to 11, wherein the battery cell assembly is used to provide electrical energy.

13. The electrical device according to claim 12, characterized in that: The electrical device comprises a shell, the shell comprises a receiving space and an escape space which are connected to each other, the battery core assembly is partially engaged in the receiving space, and the recess is engaged in the escape space.

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