Connecting piece and battery

Abstract

The invention relates to the technical field of batteries, in particular to a connecting piece and a battery, the connecting piece comprises multiple layers of foils, the multiple layers of foils are stacked in a first direction to form a connecting body, the connecting body comprises a first connecting area, a bending area and a second connecting area, and the bending area is arranged between the first connecting area and the second connecting area. The first connecting area is provided with a welding area used for being connected with a pole, a welding mark for welding a plurality of layers of foils is arranged in the welding area, and the second connecting area is used for being connected with a tab. According to the connecting piece and the battery provided by the invention, the connecting piece is easier to bend, so that not only is the fixation among the multiple layers of foils realized, but also the spacing distribution uniformity of the layers of foils in the welding region can be effectively improved; and therefore, the phenomenon of point burst in the welding process of the welding area and the pole caused by non-uniform spacing of each layer of the welding area formed by the multi-layer foil can be effectively avoided.

Description

Technical Field

[0001] This application relates to the technical field of batteries, and in particular to a connecting piece and a battery. Background Art

[0002] In the existing battery technology, a connecting piece is usually used to connect the pole column on the top cover and the pole ear on the pole group. Nowadays, the connecting piece is usually formed by continuously stamping copper sheets or aluminum sheets. The hardness and strength of the connecting piece are relatively large, which is not convenient for the connecting piece to be bent between the top cover and the pole group. Moreover, the internal stress of the bent connecting piece is relatively large, which greatly affects the stability of the connection between the pole column and the pole group. Summary of the Invention

[0003] The purpose of this application is to provide a connecting piece and a battery, so as to solve to a certain extent the technical problems existing in the prior art that nowadays the connecting piece is usually formed by continuously stamping copper sheets or aluminum sheets, the hardness and strength of the connecting piece are relatively large, it is not convenient for the connecting piece to be bent between the top cover and the pole group, and the internal stress of the bent connecting piece is relatively large, which greatly affects the stability of the connection between the pole column and the pole group.

[0004] According to the first aspect of this application, a connecting piece is provided. The connecting piece includes multiple layers of foil materials. The multiple layers of foil materials are stacked in a first direction to form a connecting body. The connecting body includes a first connecting area, a bending area, and a second connecting area. The bending area is arranged between the first connecting area and the second connecting area; The first connecting area is provided with a welding area for connecting with the pole column. Welding imprints for welding the multiple layers of foil materials are arranged in the welding area. The second connecting area is used for connecting with the pole ear.

[0005] Preferably, the first connecting area includes one or more welding areas; Multiple welding imprints are arranged in each welding area, and the multiple welding imprints are densely distributed in the welding area in an array form.

[0006] Preferably, the welding imprints form pits on the surface of the connecting body; The sum of the sizes of the pits in the first direction accounts for 50% - 80% of the size of the connecting body in the first direction.

[0007] Preferably, the distance between two adjacent welding imprints in the same welding area is greater than the span of the welding imprint in a direction perpendicular to the first direction.

[0008] Preferably, the distance between two adjacent welding imprints is 0.4 mm - 1.0 mm; The span of the welding imprint in a direction perpendicular to the first direction is 0.2 mm - 0.8 mm.

[0009] Preferably, an indentation that indents into the connection body is formed on one side of the connection body in the first direction to form the bending area; The first connection area, the bending area, and the second connection area are arranged in sequence along the second direction; The bending area extends along a third direction, the third direction intersects with the second direction, and the first direction is perpendicular to the plane determined by both the second direction and the third direction.

[0010] Preferably, the size f of the indentation in the first direction is 0.15 mm to 0.25 mm; The size e of the indentation in the second direction is 2 mm to 10 mm.

[0011] Preferably, a hole penetrating the connection body in the first direction is further provided in the bending area; The number of the holes is one or more; When the number of the holes is multiple, the multiple holes are arranged at intervals along the third direction.

[0012] Preferably, the tab is attached to one side of the second connection area in the first direction; Alternatively, at least a part of the tab is clamped between multiple layers of foils of the second connection area.

[0013] According to a second aspect of the present application, a battery is provided, including the connection piece described in any one of the above technical solutions. Therefore, it has all the beneficial technical effects of this connection piece, and details will not be repeated here.

[0014] Compared with the prior art, the beneficial effects of the present application are as follows: The connection piece provided by the present application forms a connection body by stacking multiple layers of foils in the first direction, which can effectively reduce the hardness of the connection piece and make the connection piece easier to bend. The first connection area, the bending area, and the second connection area are provided on the connection body, and the bending area is arranged between the first connection area and the second connection area to realize the function of connecting the tab and the terminal. At the same time, a welding area for connecting to the terminal is provided in the first connection area, and welding imprints for welding multiple layers of foils are provided in the welding area, which not only realizes the fixation between multiple layers of foils but also can effectively improve the uniformity of the spacing distribution of each layer of foils in the welding area, thereby effectively avoiding the phenomenon of explosion points during the welding process between the welding area formed by multiple layers of foils and the terminal due to uneven spacing between layers.

[0015] To make the above objects, features, and advantages of the present application more obvious and understandable, the following specific preferred embodiments are given in conjunction with the accompanying drawings and described in detail as follows. Description of the Drawings

[0016] In order to more clearly illustrate the specific implementation methods of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 A schematic diagram of the axonometric structure of a connecting piece provided in an embodiment of the present application; Figure 2 A schematic diagram of the front view structure of the connecting piece provided in an embodiment of the present application; Figure 3 for Figure 2 A schematic diagram of the enlarged structure of the connecting piece at position B is provided; Figure 4 for Figure 2 A schematic diagram of a cross-sectional structure of the provided connecting piece obtained by cutting along AA; Figure 5 for Figure 4 A schematic diagram of the enlarged structure of the connecting piece at position C is provided; Figure 6 for Figure 4 A schematic diagram of the enlarged structure of the connecting piece at position D is provided; Figure 7 A schematic diagram of the multi-layer foil stacking structure of the connecting sheet provided in an embodiment of the present application; Figure 8 Another schematic diagram of the structure of the multi-layer foil stacking of the connecting sheet provided in the embodiment of the present application; Figure 9 A schematic diagram of the explosion structure of a battery provided in an embodiment of the present application; Figure 10 A schematic diagram of the exploded structure of the cover plate and the connecting piece provided in an embodiment of the present application; Figure 11 A schematic diagram of the axonometric structure of the connecting piece after bending provided in an embodiment of the present application; Figure 12 A partially enlarged schematic diagram of the assembly structure of a battery provided in an embodiment of the present application; Figure 13 Another partially enlarged schematic diagram of the assembly structure of the battery provided in the embodiment of the present application; Figure 14 Another partially enlarged schematic diagram of the assembly structure of the battery provided in the embodiment of the present application; Figure 15 Another front view structural schematic diagram of the connecting piece provided in the embodiment of the present application; Figure 16Another front view structural schematic diagram of the connecting piece provided by the embodiment of the present application.

[0018] Reference numerals: 1 - Connecting piece; 11 - First connection area; 110 - Welding area; 111 - Weld mark; 12 - Second connection area; 13 - Bending area; 131 - Hole; 2 - Electrode group; 21 - Tab; 3 - Cover plate; 31 - Terminal post; 311 - Bottom plate; 312 - Connection block; 32 - First insulating member; 4 - Second insulating member; 5 - Housing.

[0019] F1 - First direction; F2 - Second direction; F3 - Third direction. Detailed implementation manners

[0020] The technical solutions of the present application will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some but not all of the embodiments of the present application.

[0021] Generally, the components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but merely represents the selected embodiments of the present application.

[0022] All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0023] In the description of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present application. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0025] Next, refer to Figures 1 to 16Describe a connecting piece and a battery according to some embodiments of the present application.

[0026] See Figures 1 to 16 As shown, an embodiment of the first aspect of the present application provides a connecting piece. The connecting piece 1 includes multiple layers of foils. The multiple layers of foils are stacked along the first direction F1 to form a connecting body. The connecting body includes a first connecting area 11, a bending area 13, and a second connecting area 12. The bending area 13 is disposed between the first connecting area 11 and the second connecting area 12. The first connecting area 11 is provided with a welding area 110 for connecting with the pole 31. Welding imprints 111 for welding the multiple layers of foils are disposed in the welding area 110. The second connecting area 12 is used for connecting with the tab 21.

[0027] For the connecting piece provided according to the above technical features, by stacking multiple layers of foils along the first direction F1 to form a connecting body, the hardness of the connecting piece 1 can be effectively reduced, making the connecting piece 1 easier to bend. The first connecting area 11, the bending area 13, and the second connecting area 12 are provided on the connecting body, and the bending area 13 is disposed between the first connecting area 11 and the second connecting area 12 to realize the function of connecting the tab 21 and the pole 31 while the connecting piece 1. The first connecting area 11 is provided with a welding area 110 for connecting with the pole 31, and welding imprints 111 for welding the multiple layers of foils are disposed in the welding area 110, which not only realizes the fixation between the multiple layers of foils but also can effectively improve the uniformity of the spacing distribution of each layer of foils in the welding area 110, and further can effectively avoid the phenomenon of explosion points during the welding process of the welding area 110 formed by the multiple layers of foils and the pole 31 due to uneven spacing between layers.

[0028] As Figures 1 to 3 shown, F1 shown in the figure can be an example of the above-mentioned first direction F1, F2 shown in the figure can be an example of the following second direction F2, and F3 shown in the figure can be an example of the following third direction F3. Among them, when the above-mentioned connecting piece 1 is in an unbent state, the second direction F2 and the third direction F3 can be cross-set, and the above-mentioned first direction F1 can intersect with the plane determined by the above-mentioned second direction F2 and the third direction F3. Preferably, any two of the above-mentioned first direction F1, second direction F2, and third direction F3 are perpendicular to each other.

[0029] As Figure 1 、 Figure 2 and Figure 10 shown, the figure shows an example in which the first connecting area 11 can include two welding areas 110 to facilitate application to a pole 31 having two base plates 311. However, it is not limited thereto. The number of welding areas 110 provided in the first connecting area 11 can be adaptively adjusted according to the structure of the pole 31. For example, the number of welding areas 110 provided in the first connecting area 11 can also be one, three, four, or more.

[0030] Preferably, as Figures 1 to 4 shown, a plurality of welding imprints 111 may be provided in each welding area 110 to further improve the fixing stability between the multi-layer foils and the uniformity of the spacing distribution of the foils in the welding area 110.

[0031] Preferably, as Figures 1 to 4 described, the plurality of welding imprints 111 in the above-mentioned welding area 110 are densely distributed in the welding area 110 in an array form to further improve the uniformity of the spacing distribution of the foils in the welding area 110. It should be noted that as long as it can be ensured that the welding imprints 111 are densely distributed in the welding area 110, the distribution form of the welding imprints 111 in the above-mentioned welding area 110 is not limited to the above-mentioned array form.

[0032] Preferably, as Figure 4 shown, the above-mentioned welding imprints 111 may form pits on the surface of the connecting body.

[0033] Optionally, the above-mentioned welding imprints 111 may be formed by laser ultrasonic welding.

[0034] Preferably, as Figure 4 shown, the above-mentioned welding imprints 111 may form pits at opposite positions on both sides of the connecting body in the first direction F1 to further improve the fixing stability of the welding imprints 111 to the multi-layer foils.

[0035] Preferably, the total size of the pits in the first direction F1 accounts for 50% - 80% of the size of the connecting body in the first direction F1. It should be noted that taking the connecting piece in which the welding imprints form pits at opposite positions on both sides of the connecting body in the first direction F1 as an example, the total size of the pits in the first direction F1 can be understood as the sum of the sizes of the two pits arranged opposite to each other on both sides of the connecting body in the first direction F1 in the first direction F1. That is to say, as Figure 4 shown, the total size of the pits in the first direction F1 accounting for 50% - 80% of the size of the connecting body in the first direction F1 can be understood as 50%T ≤ (t1 + t2) ≤ 80%T; for the connecting piece in which the welding imprints are only provided on one side of the connecting body in the first direction F1 (not shown in the figure), the size of the pits of the connecting piece in the first direction F1 accounts for 50% - 80% of the size of the connecting body in the first direction F1.

[0036] Referring to Table 1, the table shows that a plurality of embodiments with different sizes of welding imprints 111 are respectively applied with opposite pulling forces on both sides of the welding area 110 in the first direction F1. It should be noted that when the above-mentioned pulling forces applied on both sides of the welding area 110 in the first direction F1 exceed 50N, the welding area 110 can still ensure no delamination and is regarded as qualified.

[0037] From the data of Examples 1 to 16 recorded in Table 1, it can be seen that when the total dimension of the pits in the first direction F1 accounts for 50% to 80% of the dimension of the connection body in the first direction F1, the solder joints 111 of the multi-layer foil can withstand a tensile force exceeding 50N without delamination, effectively ensuring the connection strength between the layers of the foil and thus improving the connection stability of the layers of the foil of the connection body. From the data of Examples 17 to 32 recorded in Table 1, it can be seen that when the total dimension of the pits in the first direction F1 is not within the range of 50% to 80% of the dimension of the connection body in the first direction F1, the solder joints 111 of the multi-layer foil cannot withstand a tensile force exceeding 50N without delamination.

[0038] Table 1:

[0039] It should be noted that taking the example where the above-mentioned pits are formed at the relative positions on both sides of the solder joint 111 in the connection body in the first direction F1, the total dimension of the pits in the first direction F1 can be understood as the sum of the dimensions of the two pits at the relative positions on both sides of the connection body in the first direction F1 in the first direction F1.

[0040] Preferably, the distance between two adjacent solder joints 111 within the same welding area 110 is greater than the span of the solder joint 111 in the direction perpendicular to the first direction F1, so as to facilitate the manufacture of the welding area 110.

[0041] Preferably, the distance between two adjacent solder joints 111 can be 0.4mm to 1.0mm. It should be noted that the distance between two adjacent solder joints 111 here can refer to the row spacing between adjacent rows (i.e., Figure 3 shown as L1) of the solder joints 111 distributed in an array, and the distance between two adjacent solder joints 111 here can also refer to the column spacing between adjacent columns (i.e., Figure 3 shown as L2) of the solder joints 111 distributed in an array. In other words, 0.4mm ≤ L1 ≤ 1.0mm, 0.4mm ≤ L2 ≤ 1.0mm.

[0042] Preferably, the span of the solder joint 111 in the direction perpendicular to the first direction F1 can be 0.2mm to 0.8mm.

[0043] Referring to Table 1 and Table 2, from the data of Examples 1 to 16 recorded in Table 1, it can be seen that when the distance between two adjacent solder marks 111 satisfies the range of 0.4 mm to 1.0 mm, and the span of the solder mark 111 in the direction perpendicular to the first direction F1 satisfies 0.2 mm to 0.8 mm, the solder marks 111 of the multi-layer foil can withstand a tensile force exceeding 50 N without delamination, effectively ensuring the connection strength between the layers of the foil, and further improving the connection stability of the layers of the connection body. From the data of Examples 33 to 48 recorded in Table 2, it can be seen that even if the ratio h / H of the depth of the solder mark 111 to the thickness of the connecting piece satisfies the above range of 50% to 80%, but the distance between two adjacent solder marks 111 does not satisfy the range of 0.4 mm to 1.0 mm or the span of the solder mark 111 in the direction perpendicular to the first direction F1 does not satisfy the range of 0.2 mm to 0.8 mm, the solder marks 111 of the multi-layer foil still cannot withstand a tensile force exceeding 50 N without delamination.

[0044] Table 2:

[0045] Preferably, taking Figure 3 the above-mentioned concave pit shown as an example of a square pit, the span of the above solder mark 111 in the direction perpendicular to the first direction F1 can be understood as the side length of this square pit (i.e., Figure 3 S1 and S2 shown).

[0046] Optionally, not shown in the figure, the above concave pit can also be a circular pit (such as Figure 15 shown), correspondingly, the span of the above solder mark in the direction perpendicular to the first direction F1 can be understood as the diameter of the circular pit.

[0047] However, it is not limited to this. The shape of the above concave pit is not limited to the above square pit and circular pit, and can also be a triangular pit (such as Figure 16 shown), a pentagram pit or other regular / irregular shaped concave pits.

[0048] Optionally, the above foil can be aluminum foil, copper foil, etc.

[0049] Optionally, the thickness of the above foil in the first direction F1 can be 0.1 mm, 0.2 mm, 0.3 mm.

[0050] In the embodiment, preferably, as Figures 6 to 8 shown, the figure shows an example of a connection body formed by stacking multi-layer foils in three different ways along the first direction F1.

[0051] Example 1, as Figure 6 shown, the figure shows an example of a connection body formed by stacking multiple U-shaped foil groups, where the U-shaped foil group is formed by stacking multi-layer foils and folding along the center line.Figure 6 An example is shown in which the U-shaped foil group includes two layers of foils, and the connecting body includes two U-shaped foil groups. However, it is not limited thereto. The number of foil layers and the number of U-shaped foil groups can be adaptively adjusted according to the size of the connecting body in the first direction F1 and the size of the foils in the first direction F1.

[0052] Example two, as Figure 7 shown, the figure shows an example in which a base material is formed by stacking multiple layers of foils, and the connecting body is formed by reciprocally winding the base material in a serpentine line. Figure 7 An example is shown in which the base material includes two layers of foils. However, it is not limited thereto. The number of foil layers and the number of reciprocating winding passes of the base material can be adaptively adjusted according to the size of the connecting body in the first direction F1 and the size of the foils in the first direction F1.

[0053] Example three, as Figure 8 shown, the figure shows an example of a connecting body formed by simply stacking multiple layers of foils. It should be noted that as long as the multi-layer foil structure of the connecting body can be realized, the stacking method of the above foils is not limited to the above form.

[0054] In the embodiment, as Figures 1 to 4 shown, an indentation that indents into the connecting body is formed on one side of the connecting body in the first direction F1 to form a bending area 13. The first connecting area 11, the bending area 13, and the second connecting area 12 are arranged in sequence along the second direction F2. The bending area 13 extends along the third direction F3. Thus, on the one hand, the connection stability between the foil layers can be further improved through this indentation; on the other hand, through the bending area 13 formed by the indentation, the pre-bending and shaping of the bending area 13 are realized, and then it is convenient for the connecting body to be bent and formed.

[0055] Preferably, as Figure 5 shown, the size of the above indentation in the first direction F1 (i.e., the f value shown in the figure) can be 0.15 mm to 0.25 mm. For example, the size of the indentation in the first direction F1 can be 2 mm, which is beneficial for the first connecting area 11 and the second connecting area 12 to be bent along the bending area 13, so as to facilitate the connecting piece 1 to be formed into the bending state of the connecting piece 1 as Figure 11 shown.

[0056] Preferably, as Figure 1 and Figure 4 shown, the size of the indentation in the second direction F2 (i.e., the e value shown in the figure) can be 2 mm to 10 mm to adapt to the installation space of the connecting piece 1.

[0057] Preferably, as Figure 1 、 Figure 2 、 Figure 10 andFigure 11 As shown, the above-mentioned bending area 13 may also be provided with holes 131 penetrating through the connecting body along the first direction F1. In this way, on the one hand, through the holes 131, the bending sensitivity of the bending area 13 can be effectively improved to facilitate the bending operation of the connecting piece 1; on the other hand, through the holes 131, the internal stress generated between the layers of foil materials during the bending process can be effectively released to improve the stability of the bending area 13.

[0058] Such as Figure 1 , Figure 2 , Figure 10 and Figure 11 As shown, the figure shows an example where the number of the above-mentioned holes 131 is two, and the two holes 131 are arranged at intervals along the third direction F3 to ensure the uniformity of the release of the internal stress of the bending area 13 by the holes 131.

[0059] However, it is not limited thereto. The number of the holes 131 can be adaptively adjusted according to the size of the connecting piece 1 in the third direction F3 and the designed current-carrying capacity of the connecting piece 1. For example, the number of the holes 131 can also be 1, 3, 4 or more.

[0060] In the embodiment, as Figures 12 to 14 shown, the figure shows two different connection methods between the tab 21 and the second connection area 12.

[0061] Optionally, in the first method, as Figure 12 and Figure 14 shown, the tab 21 can be attached to one side of the second connection area 12 in the first direction F1.

[0062] Preferably, in the second method, as Figure 13 shown, at least a part of the tab 21 is clamped between the multiple layers of foil materials of the second connection area 12, which can not only improve the connection stability between the tab 21 and the connecting piece 1, but also increase the connection area between the tab 21 and the connecting piece 1 to ensure the current-carrying capacity between the tab 21 and the connecting piece 1.

[0063] Optionally, not shown in the figure, the above-mentioned tab 21 and the second connection area 12 can be connected by laser ultrasonic welding to ensure the connection stability between the tab 21 and the connecting piece 1.

[0064] Referring to Figures 9 to 14 , the embodiment of the second aspect of the present application also provides a battery, including the connecting piece described in any of the above embodiments. Therefore, it has all the beneficial technical effects of the connecting piece, and will not be elaborated here.

[0065] Preferably, as Figure 9As shown, the above-mentioned battery may further include a housing 5, a battery cell assembly 2, and a cover plate 3. The housing 5 encloses a space for accommodating the battery cell assembly 2, and the cover plate 3 covers opposite ends of the housing 5. Among them, a terminal post 31 is provided on the cover plate 3, and electrode tabs 21 are provided at both ends of the battery cell assembly 2 opposite to the cover plate 3. The electrode tabs 21 are electrically connected to the terminal posts 31 on the corresponding cover plate 3 through the above-mentioned connecting piece 1.

[0066] As Figure 9 and Figure 10 shown, the figure shows an example in which the terminal post 31 includes a connecting block 312 and two bottom plates 311. The two bottom plates 311 penetrate through the cover plate 3 and are connected to the connecting block 312. Correspondingly, the first connection area 11 of the above-mentioned connecting piece 1 may include two welding areas 110 to be respectively welded to the two bottom plates 311.

[0067] Optionally, as Figures 12 to 14 shown, the above-mentioned battery may further include a first insulating member 32. The first insulating member 32 may be disposed between the connecting block 312 and the cover plate 3 to achieve insulation between the connecting block 312 and the cover plate 3.

[0068] Optionally, as Figure 9 , Figure 10 , Figures 12 to 14 shown, the above-mentioned battery may further include a second insulating member 4. The second insulating member 4 may be disposed on a side of the cover plate 3 facing the battery cell assembly 2 to achieve insulation between the cover plate 3 and the battery cell assembly 2.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A connecting sheet, characterized in that: The connecting sheet (1) comprises a plurality of layers of foil, wherein the plurality of layers of foil are stacked along a first direction (F1) to form a connecting body, wherein the connecting body comprises a first connecting area (11), a bending area (13) and a second connecting area (12), wherein the bending area (13) is arranged between the first connecting area (11) and the second connecting area (12); The first connection area (11) is provided with a welding area (110) for connecting to a pole (31), and a welding mark (111) for welding the multi-layer foil is provided in the welding area (110), and the second connection area (12) is used for connecting to a pole lug (21).

2. The connecting piece according to claim 1, characterized in that: The first connection area (11) includes one or more welding areas (110); A plurality of welding marks (111) are arranged in each welding area (110), and the plurality of welding marks (111) are distributed in the welding area (110) in an array form.

3. The connecting sheet according to claim 1, characterized in that: The welding mark (111) forms a pit on the surface of the connecting body; The sum of the dimensions of the pits in the first direction (F1) accounts for 50% to 80% of the dimension of the connection body in the first direction (F1).

4. The connecting sheet according to claim 2, characterized in that: The distance between two adjacent weld marks (111) in the same weld zone (110) is greater than the span of the weld mark (111) in a direction perpendicular to the first direction (F1).

5. The connecting piece according to claim 4, characterized in that: The distance L1 between two adjacent welding marks (111) is 0.4 mm to 1.0 mm; And / or, the span of the weld mark (111) perpendicular to the first direction (F1) is 0.2 mm to 0.8 mm.

6. The connecting piece according to any one of claims 1 to 5, characterized in that: An indentation is formed on one side of the connecting body in the first direction (F1) and is recessed into the connecting body to form the bending area (13); The first connection area (11), the bending area (13) and the second connection area (12) are arranged in sequence along the second direction (F2); The bending zone (13) extends along a third direction (F3), the third direction (F3) intersects the second direction (F2), and the first direction (F1) is perpendicular to a plane defined by the second direction (F2) and the third direction (F3).

7. The connecting piece according to claim 6, characterized in that: The dimension f of the indentation in the first direction (F1) is 0.15 mm to 0.25 mm; A dimension e of the indentation in the second direction (F2) is 2 mm to 10 mm.

8. The connecting sheet according to claim 6, characterized in that: The bending area (13) is also provided with a hole (131) penetrating the connecting body along the first direction (F1); The number of the holes (131) is one or more; When the number of the holes (131) is plural, the plurality of holes (131) are arranged at intervals along the third direction (F3).

9. The connecting sheet according to claim 1, characterized in that: The pole ear (21) is in contact with one side of the second connection area (12) in the first direction (F1); Alternatively, at least a portion of the electrode tab (21) is sandwiched between the multiple layers of foil in the second connection area (12).

10. A battery, characterized in that: The invention comprises the connecting piece (1) according to any one of claims 1 to 9.

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