Tab, monomer battery and battery pack

Abstract

The application provides a connecting sheet, a single battery and a battery pack, and relates to the technical field of lithium ion batteries. The connecting sheet comprises a pole column area for being connected with a pole column and a first tab area for being connected with a multi-layer tab, which are connected with each other, the first tab area has a first end connected with the pole column area and a second end away from the pole column area, the width is the size in the direction perpendicular to the first end to the second end, and the width of the first tab area gradually decreases in the direction from the first end to the second end. The multi-layer tab can be welded on the connecting sheet in the way of edge welding or side welding, and the width of the first tab area gradually decreases in the direction from the first end to the second end, which can not only reduce the material of the connecting sheet, but also meet the overcurrent capacity of the connecting sheet and ensure the effective welding of the multi-layer tab.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, in particular to a connecting sheet, a single battery and a battery pack. BACKGROUND

[0002] Generally, a lithium ion single battery includes a shell, a top cover assembly and two cell assemblies, each of which has a plurality of layers of positive and negative tabs. In order to lead out the current generated by the cell, the plurality of layers of positive tabs of the two cell assemblies are welded at both ends of a positive soft connecting sheet, and the positive soft connecting sheet is welded with a positive pole of the top cover assembly; the plurality of layers of negative tabs of the two cell assemblies are welded at both ends of a negative soft connecting sheet, and the negative soft connecting sheet is welded with a negative pole of the top cover assembly, and then the current is led out through the positive and negative poles on the top cover assembly.

[0003] Figure 1 The structure of the soft connecting sheet in the prior art is shown in the figure. Please refer to Figure 1 Taking the positive soft connecting sheet as an example, the soft connecting sheet includes a pole connecting area 10, a first tab connecting area 21 and a second tab connecting area 22, the first tab connecting area 21 and the second tab connecting area 22 are connected with the pole connecting area 10, and the first tab connecting area 21 and the second tab connecting area 22 are both square and spaced apart. In order to realize the welding of the first tab connecting area 21 and the plurality of layers of tabs of one cell assembly, and the welding of the second tab connecting area 22 and the plurality of layers of tabs of another cell assembly, the plurality of layers of tabs are overlapped on the tab connecting area, and then a metal sheet is placed above the plurality of layers of tabs, and the welding between the plurality of layers of tabs and the tab connecting area is realized by ultrasonic welding, forming Figure 1 a square ultrasonic welding area 23 as shown, which is basically located in the middle of the square tab connecting area. SUMMARY

[0004] The inventor found that in addition to using ultrasonic welding to weld the plurality of layers of tabs, side welding or edge welding can also be used to weld the plurality of layers of tabs, which can be realized by a cold welding machine. When welding, the end of the plurality of layers of tabs is fusion welded on the side or edge of the tab connecting area, and the welding area can be significantly reduced.

[0005] Based on the above welding method, the present application provides a connecting sheet, a single battery and a battery pack, which can reduce the material of the connecting sheet and meet the overcurrent capacity and the welding of the plurality of layers of tabs.

[0006] In a first aspect, the embodiments of the present application provide a connecting tab, comprising a pole column region for connecting with a pole column and a first tab region for connecting with a multi-layer tab, the first tab region having a first end connected with the pole column region and a second end away from the pole column region, the width of the first tab region gradually decreases along a direction from the first end to the second end.

[0007] Since the welding is performed in the way of side welding or edge welding, the welding mark area is a long strip structure, and the width of the welding mark area is significantly reduced (the welding mark area is narrowed) compared with the ultrasonic welding. Therefore, the width of the first tab region of the connecting tab gradually decreases along the direction from the first end to the second end, which on the one hand reduces the width of the end of the first tab region away from the pole column region, saves the material of the connecting tab, increases the energy density of the battery, and meets the requirements of side welding or edge welding. On the other hand, the width of the position of the first tab region connected with the pole column region is large, which can ensure the current-carrying capacity of the connecting tab (during the operation of the single battery, the current is larger near the pole column, the width of the region of the first tab region near the pole column is large, which can meet the current-carrying capacity of the connecting tab).

[0008] In a possible implementation, the connecting tab further comprises a second tab region connected with the pole column region, the extension direction of the first tab region away from the pole column region is consistent with the extension direction of the second tab region away from the pole column region, and the width of the second tab region also gradually decreases along the direction from the first end to the second end.

[0009] Through the arrangement of the first tab region and the second tab region, the multi-layer tabs of two battery cell assemblies can be connected, and the energy density of the battery can be increased. The width of the second tab region also gradually decreases, and the amount of material of the second tab region can also be reduced, and the multi-layer tab welding and current-carrying of the two battery cell assemblies can be met.

[0010] In a possible implementation, an opening is arranged between the first tab region and the second tab region, and the width of the opening gradually increases along the direction from the first end to the second end.

[0011] The first tab region and the second tab region are separated at the end away from the pole column region, which can facilitate the edge welding or side welding of the multi-layer tab on the side of the first tab region away from the second tab region and the side of the second tab region away from the first tab region.

[0012] In a possible implementation, the side of the first tab region away from the second tab region and the side of the second tab region away from the first tab region are parallel.

[0013] Since the two side edges of the first and second tab areas are parallel, the two side profiles of the cell assembly and the two side profiles of the connecting sheet are substantially parallel when the cell assembly is installed in cooperation with the cell assembly, and no torsion is generated when the multi-layer tab is welded except for the bending for welding, which can avoid the middle part of the tab from bearing the torque to some extent, and the welding effect of the tab is better.

[0014] In a possible implementation, the first and second tab areas are symmetrically arranged.

[0015] Since the first and second tab areas have the same structure and the outer profiles of the first and second tab areas are parallel, the first and second tab areas are substantially right-angled trapezoidal or right-angled triangular structures, the structure of the connecting sheet is relatively reasonable, and the forces borne by the first and second tab areas are substantially consistent, and the welding effect of the multi-layer tab is better.

[0016] In a possible implementation, the wall surface of the opening has a first side surface, a connecting surface and a second side surface connected in sequence, and the first and second side surfaces are planes.

[0017] On the one hand, the structure of the connecting sheet is relatively simple and easy to manufacture; on the other hand, the structural defects of the connecting sheet can be reduced, and the strength of the connecting sheet is relatively high, meeting the welding requirements.

[0018] In a possible implementation, the end surface of the second end is a plane, the width of the second end is 1-5 mm, and the thickness of the connecting sheet is 0.5-1.5 mm.

[0019] The width and thickness can meet the edge welding or side welding of the multi-layer tab and the connecting sheet.

[0020] In a possible implementation, the first and second tab areas are symmetrically arranged.

[0021] In the single battery, since the multi-layer tab is welded to the tab area of the connecting sheet by the edge welding or side welding, the multi-layer tab can be firmly welded. At the same time, the area of the connecting sheet is reduced, the material of the connecting sheet can be saved, and the energy density of the battery is increased.

[0022] In a possible implementation, the connecting sheet further comprises a second tab area connected with the pole column area, the extension direction of the first tab area away from the pole column area is consistent with the extension direction of the second tab area away from the pole column area, and the width of the second tab area gradually decreases along the direction from the first end to the second end. The multi-layer tabs of one battery cell assembly are welded to one side of the first tab area away from the second tab area by side welding or edge welding, and the multi-layer tabs of another battery cell assembly are welded to one side of the second tab area away from the first tab area by side welding or edge welding.

[0023] Through the arrangement of the first tab area and the second tab area, the multi-layer tabs of the two battery cell assemblies can be connected by side welding or edge welding, so that the energy density of the battery can be increased, the material consumption can be reduced, and the welding and overcurrent of the multi-layer tabs of the two battery cell assemblies can be met.

[0024] In a third aspect, the application provides a battery pack, comprising a battery box and a plurality of single batteries as described above, and the single batteries are arranged in the battery box. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0026] Figure 1 A structural schematic diagram of a soft connecting sheet provided by the prior art is shown in FIG. 1.

[0027] Figure 2 A first internal structural schematic diagram of a single battery provided by the embodiments of the application is shown in FIG. 2.

[0028] Figure 3 A second internal structural schematic diagram of a single battery provided by the embodiments of the application is shown in FIG. 3.

[0029] Figure 4 A third internal structural schematic diagram of a single battery provided by the embodiments of the application is shown in FIG. 4.

[0030] Figure 5 A structural schematic diagram of a connecting sheet provided by the embodiments of the application is shown in FIG. 5. Figure 3 An enlarged view of the position V in FIG. 5 is shown in FIG. 6.

[0031] Figure 6 An enlarged view of the position VI in FIG. 5 is shown in FIG. 7. Figure 4 An enlarged view of the position VI in FIG. 5 is shown in FIG. 7.

[0032] Figure 7 A structural schematic diagram of a connecting sheet provided by the embodiments of the application is shown in FIG. 5.

[0033] Figure 8 This is a schematic diagram of the second structure of the connecting piece provided in an embodiment of this application;

[0034] Figure 9 This is a schematic diagram of the third structure of the connecting piece provided in an embodiment of this application.

[0035] Icons: 10 - Terminal connection area; 21 - First electrode connection area; 22 - Second electrode connection area; 23 - Ultrasonic welding area; 110 - First cell assembly; 120 - Second cell assembly; 130 - Positive electrode connecting piece; 140 - Negative electrode connecting piece; 111 - Multilayer first positive electrode tab; 112 - Multilayer first negative electrode tab; 121 - Multilayer second positive electrode tab; 122 - Multilayer second negative electrode tab; 141 - Positive terminal; 142 - Negative terminal; 151 - Terminal area; 152 - First electrode tab area; 153 - Second electrode tab area; 1521 - First end; 1522 - Second end; 154 - Soldering area; 155 - Opening; 1551 - First side surface; 1552 - Connection surface; 1553 - Second side surface. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings.

[0037] This application provides a battery pack for an electrical device, such as a new energy vehicle or an electric vehicle. The battery pack includes a battery housing and multiple individual batteries, with the individual batteries housed within the battery housing.

[0038] Since new energy vehicles are large electrical devices that require higher voltage, each individual battery can contain two cell assemblies to increase the battery's energy density. Figure 2 This is a schematic diagram of the first internal structure of a single battery provided in an embodiment of this application; Figure 3 This is a schematic diagram of the second internal structure of a single battery provided in an embodiment of this application; Figure 4 This is a schematic diagram of the third internal structure of a single battery cell provided in an embodiment of this application. Please refer to [link / reference]. Figures 2-4 In this application, a single battery cell includes a battery casing and a top cover assembly. Figure 2 (Not shown) A first cell assembly 110, a second cell assembly 120, a positive electrode connector 130, and a negative electrode connector 140. The first cell assembly 110 and the second cell assembly 120 are installed inside the battery casing. The positive electrode connector 130 and the negative electrode connector 140 are connected to the top cover assembly and the first cell assembly 110 and the second cell assembly 120, respectively, to draw out the current generated by the cell assemblies.

[0039] The positive connection sheet 130 and the negative connection sheet 140 have the same structure, and the materials thereof can be different. For example, the positive connection sheet 130 is an aluminum sheet, and the negative connection sheet 140 is a copper sheet. Alternatively, the thicknesses of the positive connection sheet 130 and the negative connection sheet 140 are both 0.5-1.5 mm. Since the thicknesses thereof are relatively small, the connection sheets can be deformed to a certain extent, and the connection sheets can also be called soft connection sheets. As an example, the thickness of the connection sheet can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm.

[0040] In the present application, the first cell assembly 110 includes a plurality of layers of first positive tabs 111 and a plurality of layers of first negative tabs 112; the second cell assembly 120 includes a plurality of layers of second positive tabs 121 and a plurality of layers of second negative tabs 122, the top cover assembly includes a positive pole 141 and a negative pole 142, the plurality of layers of first positive tabs 111 and the plurality of layers of second positive tabs 121 are welded on the positive connection sheet 130, the positive connection sheet 130 is welded on the positive pole 141, the plurality of layers of first negative tabs 112 and the plurality of layers of second negative tabs 122 are welded on the negative connection sheet 140, and the negative connection sheet 140 is welded on the negative pole 142. The current is led out through the positive pole 141 and the negative pole 142 of the top cover assembly.

[0041] The positive connection sheet 130 includes a positive tab area and a positive pole 141 area connected to each other, and the negative connection sheet 140 includes a negative tab area and a negative pole 142 area connected to each other. The positive tab area is welded with the plurality of layers of first positive tabs 111 and the plurality of layers of second positive tabs 121, the positive pole 141 area is welded with the positive pole 141, the negative tab area is welded with the plurality of layers of first negative tabs 112 and the plurality of layers of second negative tabs 122, and the negative pole 142 area is welded with the negative pole 142, so as to realize the electrical connection between the cell assembly and the pole.

[0042] Since the structures of the positive connection sheet and the negative connection sheet are basically the same, the structure of the connection sheet is described in detail below, which is applicable to both the positive connection sheet and the negative connection sheet.

[0043] In the prior art, a plurality of layers of tabs are overlapped on a tab connection area, and then a metal sheet is placed above the plurality of layers of tabs. The welding between the plurality of layers of tabs and the tab connection area is realized by ultrasonic welding, forming a square ultrasonic welding area 23 (as shown in Figure 1 Figure 1 The ultrasonic welding area 23 is basically located in the middle of the square tab connection area, and the length of the ultrasonic welding area 23 is about 5-50 mm, and the width thereof is about 3-25 mm.

[0044] ​Figure 5 for Figure 3 Enlarged view at point V; Figure 6 for Figure 4 Enlarged view at point VI; Figure 7 This is a first structural schematic diagram of the connecting piece provided in an embodiment of this application. Please refer to... Figures 3-7 In this application, side welding is performed using a cold welding machine (e.g., Figure 6 ) or edge welding (such as Figure 5 The welding is performed in a fusion welding manner, which allows the ends of the multi-layer tabs to be directly fused together with the tab area, forming a long strip-shaped weld area. The weld area 154 during side welding is shown in the image. Figure 7 The length of the solder area 154 is 5-50mm, and the width is 0.5-2.5mm. The width of the solder area 154 is significantly reduced (the solder area 154 becomes narrower); the welding area during edge welding is located on the side of the tab area. Figure 7 (Not shown).

[0045] Please continue reading. Figure 7 In this application, the connecting piece includes a pole post region 151, a first tab region 152, and a second tab region 153. Both the first tab region 152 and the second tab region 153 are connected to the pole post region 151, and the ends of the first tab region 152 and the second tab region 153 that are away from the pole post region 151 both extend in the same direction. Figure 7 As shown, Figure 7 The vertical dashed line 1 in the diagram can divide the connecting piece into the pole post area 151 and the tab area. Figure 7 The horizontal dashed line 2 divides the tab region into a first tab region 152 and a second tab region 153. This division method is not a standard division method, but is only made for the convenience of subsequent description, and does not limit the scope of protection of this application.

[0046] The first tab region 152 has a first end 1521 connected to the pole post region 151 and a second end 1522 away from the pole post region 151. Its width is defined by a dimension perpendicular to the direction from the first end 1521 to the second end 1522. Along this direction, the width of the first tab region 152 gradually decreases, and the width of the second tab region 153 also gradually decreases. The pole post is welded to the pole post region 151 of the connecting piece. The first multilayer tab is connected to the first tab region 152 by side welding or edge welding, and the second multilayer tab is connected to the second tab region 153 by side welding or edge welding.

[0047] The width of the tab area (the first tab area 152 or / and the second tab area 153) of the connecting tab gradually decreases from the first end 1521 to the second end 1522, and the width of the second end 1522 of the tab area (the width of the end of the first tab area 152 and the second tab area 153 away from the pole area 151) is reduced. On the one hand, the material of the connecting tab is saved, the energy density of the battery is increased, and the requirements of side welding or edge welding and the like can be met. On the other hand, the position of the tab area connected to the pole area 151 has a larger width, which can ensure the overcurrent capacity of the connecting tab (in the process of operation of the single battery, the closer to the pole, the greater the current, and the width of the area of the tab area close to the pole is larger, which can meet the overcurrent capacity of the connecting tab).

[0048] Optionally, the end surface of the second end 1522 is a plane, the width of the second end 1522 is 2-3mm, the width of the second end 1522 of the first tab area 152 is 1-5mm, and the width of the second end of the second tab area 153 is also 1-5mm. The width can meet the edge welding or side welding of the multi-layer tab and the connecting tab. As an example, the width of the second end 1522 is 1mm, 2mm, 3mm, 4mm or 5mm.

[0049] Please continue to refer to Figure 7 An opening 155 is arranged between the first tab area 152 and the second tab area 153, and the width of the opening 155 gradually increases from the first end 1521 to the second end 1522. The first tab area 152 and the second tab area 153 are separated at the end away from the pole area 151, which can facilitate the edge welding or side welding of the multi-layer tab on the side of the first tab area 152 away from the second tab area 153 and the side of the second tab area 153 away from the first tab area 152.

[0050] Optionally, the side of the first tab area 152 away from the second tab area 153 and the side of the second tab area 153 away from the first tab area 152 are parallel. Since the two side edges of the first tab area 152 and the second tab area 153 are parallel, the two side profiles of the battery cell assembly and the two side profiles of the connecting tab are basically parallel when the battery cell assembly is installed in cooperation with the connecting tab. In addition to bending for welding, no torsion will be generated when the multi-layer tab is welded, which can to some extent avoid the middle part of the tab bearing torsional force, and the welding effect of the tab is better.

[0051] Further, the first tab area 152 and the second tab area 153 are symmetrically arranged. The first tab area 152 and the second tab area 153 have the same structure, and the outer contours of the first tab area 152 and the second tab area 153 are parallel. The tab area is basically a square structure, and the first tab area 152 and the second tab area 153 are basically right-angled trapezoidal or right-angled triangular structures. When welding the multi-layer tabs, the multi-layer tabs of the two cell assemblies are respectively welded at the right angle side or the position close to the right angle side of the right-angled trapezoidal or right-angled triangular structure. At this time, the multi-layer tabs will not be twisted when being welded, and the middle part of the tab can be prevented from bearing the torque to some extent, and the welding effect of the tab is better.

[0052] Please continue to refer to Figure 7 The wall surface of the opening 155 has a first side surface 1551, a connecting surface 1552 and a second side surface 1553 connected in sequence, and the first side surface 1551 and the second side surface 1553 are planes. On the one hand, the structure of the connecting sheet is relatively simple and easy to prepare; on the other hand, the structural defects of the connecting sheet can be reduced, and the strength of the connecting sheet is relatively high, which meets the welding requirements.

[0053] Further, the connecting surface 1552 is a circular arc surface, and the direction of the circular arc surface towards the pole column area 151 is concave. The opening 155 at the side of the tab area (the first tab area 152 and the second tab area 153) close to the pole column area 151 is a circular arc surface, which can make the pole column area 151 and the part of the tab area close to the pole column area 151 form a region for welding the pole column (for example, the region of the dotted circle). Figure 1 The firm welding of the pole column can be ensured, the overall area of the connecting sheet is reduced, and at the same time, the area close to the pole column area 151 of the tab area can have a large flow area, which ensures the flow and reduces the use of materials.

[0054] In the present application, the direction from the first end 1521 to the second end 1522 is the length direction, the distance between the circular arc surface and the connecting line of the tab area and the pole column area 151 is 0.3-0.8 times the length of the pole column area 151, that is, the distance a between the circular arc surface and the dotted line 1 is 0.3-0.8 times the distance b between the left edge of the pole column area 151 and the dotted line 1. The pole column area 151 and the tab area close to the pole column area 151 can both weld the pole column, and the size of the connecting sheet meets the above conditions, which can make the length of the pole column area 151 shorter, so as to meet the welding of the pole column, thereby reducing the material consumption of the connecting sheet. As an example, the distance a is 0.3 times, 0.4 times, 0.5 times, 0.6 times, 0.7 times or 0.8 times the distance b.

[0055] Optionally, the pole column region 151 is a square structure, the width of the tab region (the distance between the side of the first tab region 152 away from the second tab region 153 and the side of the second tab region away from the first tab region) is 1.5-3 times the width of the pole column region 151, and the pole column region 151 is connected to the middle of one side (dotted line 1) of the tab region. When the connecting tab is installed, the connecting tab is located on the side of the battery cell assembly close to the top cover assembly, and the width of the tab region and the pole column region 151 is limited within the above range, which on the one hand can facilitate the welding of the pole column region 151 and the pole column, and on the other hand can make the multi-layer tab after bending be directly welded on the edge of the tab region (convenient for edge welding or side welding), to a certain extent, reduce the length of the tab, so as to increase the energy density of the battery. As an example, the width of the tab region is 1.5 times, 2 times, 2.5 times or 3 times the width of the pole column region 151.

[0056] Please continue to refer to Figure 7 and Figure 1 In this application, the structure of the connecting tab in Figure 2 is changed to the structure of the connecting tab in Figure 8 On the one hand, the overcurrent capacity of the connecting tab can be guaranteed, and on the other hand, the improvement is not much on the basis of the original connecting tab, and directly changing the original square tab connecting region to the first tab region 152 and the second tab region 153 in the shape of right triangle or right trapezoid in this application can achieve the purpose of saving materials to increase the energy density of the battery, and the improvement is more convenient; the third aspect is that the main structure of the connecting tab is basically unchanged, the connection with the pole column and the position in the single battery are basically unchanged, and the original battery manufacturing process can be completed.

[0057] Figure 8 The second structure diagram of the connecting tab provided in the embodiment of the application is provided. Please refer to Figure 9 In this embodiment, a welding mark area 154 is arranged on the first tab region 152, which can meet the use of the battery containing one battery cell assembly in the single battery, and can also reduce the material of the adapter piece to a certain extent, increase the energy density of the battery, and achieve the purpose of cooperating with side welding or edge welding to weld multi-layer tabs.

[0058] Figure 9 The third structure diagram of the connecting tab provided in the embodiment of the application is provided. Please refer to Figure 7 Compared with Figure 1 , although the area of the connecting tab is increased, it is still smaller than ​The area of the connecting piece in the single battery is increased, and the connecting area between the pole column area 151 and the first tab area 152 and the connecting area between the pole column area 151 and the second tab area 153 are larger, so that the flow area between the tab area and the pole column area 151 is ensured, and the flow effect is better.

[0059] In the embodiment of the application, the preparation method of the single battery is as follows: the positive pole column 141 area of the positive connecting piece 130 and the part of the positive tab area close to the positive pole column 141 area are welded on the positive pole column 141 of the top cover assembly, and the negative pole column 142 area of the negative connecting piece 140 and the part of the negative tab area close to the negative pole column 142 area are welded on the negative pole column 142 of the top cover assembly; the first cell assembly 110 and the second cell assembly 120 are arranged in the battery shell, the multiple layers of positive tabs of the first cell assembly 110 are welded on the first tab area 152 of the positive connecting piece 130 by side welding or edge welding (side welding on the side of the first tab area 152 of the positive connecting piece 130 away from the second tab area 153, and edge welding on the edge of the first tab area 152 of the positive connecting piece 130 away from the second tab area 153), the multiple layers of positive tabs of the second cell assembly 120 are welded on the second tab area 153 of the positive connecting piece 130 by side welding or edge welding (side welding on the side of the second tab area 153 of the positive connecting piece 130 away from the first tab area 152, and edge welding on the edge of the second tab area 153 of the positive connecting piece 130 away from the first tab area 152), the multiple layers of negative tabs of the second cell assembly 120 are welded on the first tab area 152 of the negative connecting piece 140 by side welding or edge welding (side welding on the side of the first tab area 152 of the negative connecting piece 140 away from the second tab area 153, and edge welding on the edge of the first tab area 152 of the negative connecting piece 140 away from the second tab area 153), and the multiple layers of negative tabs of the second cell assembly 120 are welded on the second tab area 153 of the negative connecting piece 140 by side welding or edge welding (side welding on the side of the second tab area 153 of the negative connecting piece 140 away from the first tab area 152, and edge welding on the edge of the second tab area 153 of the negative connecting piece 140 away from the first tab area 152); the battery shell and the metal cover plate of the top cover assembly are welded, and then the single battery is obtained after liquid injection.

[0060] The connecting piece, the single battery, the battery pack and the electric device provided in the embodiment of the application have the beneficial effects as follows.

[0061] (1), because the multi-layer tabs are welded on the adapter plate by side welding or edge welding, the width of the welding mark area 154 is significantly reduced, so the width of the tab area (first tab area 152 or / and second tab area 153) in the adapter plate gradually decreases from the first end 1521 to the second end 1522, that is, the width of the tab area at the position connected to the pole area 151 is larger, and the width of the tab area away from the pole area 151 is smaller, and the smaller width area can meet the side welding; and the material of the connecting plate can be saved, and the energy density of the battery is increased.

[0062] (2), when welding the multi-layer tabs, the multi-layer tabs of the two cell assemblies are respectively welded at the position of the straight angle side (side welding) or close to the straight angle side (edge welding) of the diameter triangle or right angle trapezoid, at this time, the multi-layer tabs will not be twisted when welding, except for bending for welding, which can to some extent avoid the middle part of the tab bearing torque, and the welding effect of the tab is better.

[0063] (3), the original square tab connection area is directly changed into the first tab area 152 and the second tab area 153 in the shape of right triangle or right trapezoid, without the need to greatly improve the connecting plate, which can achieve the purpose of saving materials, so as to increase the energy density of the battery, and the improvement is more convenient; because the main structure of the connecting plate is basically unchanged, the connection with the pole and the position in the single battery are basically unchanged, which can be completed in the original battery manufacturing process.

[0064] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A tab, characterized in that The connecting sheet comprises a pole column area for connecting with a pole column and a first tab area for connecting with a multi-layer tab, the first tab area has a first end connected with the pole column area and a second end away from the pole column area, the width of the first tab area gradually decreases along the direction from the first end to the second end; The connecting sheet further comprises a second tab area connected with the pole column area, the extending direction of the first tab area away from the pole column area is consistent with the extending direction of the second tab area away from the pole column area, and the width of the second tab area also gradually decreases along the direction from the first end to the second end; An opening is arranged between the first tab area and the second tab area, the width of the opening gradually increases along the direction from the first end to the second end, a first multi-layer tab is connected with the first tab area by side welding or edge welding, and a second multi-layer tab is connected with the second tab area by side welding or edge welding; The pole column area and the part of the first tab area and the second tab area close to the pole column area jointly form an area for welding the pole column.

2. The tab of claim 1, wherein The side edge of the first tab area away from the second tab area is parallel to the side edge of the second tab area away from the first tab area.

3. The tab according to claim 2, characterized in that The first tab area and the second tab area are symmetrically arranged.

4. The tab of claim 1, wherein The wall surface of the opening has a first side surface, a connecting surface and a second side surface connected in sequence, and the first side surface and the second side surface are both planes.

5. The tab according to any one of claims 1-4, characterized in that The end surface of the second end is a plane, the width of the second end is 1-5 mm, and the thickness of the connecting sheet is 0.5-1.5 mm.

6. A single cell characterized by, The connecting sheet further comprises a second tab area connected with the pole column area, the extending direction of the first tab area away from the pole column area is consistent with the extending direction of the second tab area away from the pole column area, and the width of the second tab area also gradually decreases along the direction from the first end to the second end; one multi-layer tab of the battery cell assembly is welded to one side of the first tab area away from the second tab area by side welding or edge welding, and another multi-layer tab of the battery cell assembly is welded to one side of the second tab area away from the first tab area by side welding or edge welding.

7. The cell according to claim 6, wherein The connecting sheet further comprises a second tab area connected with the pole column area, the extending direction of the first tab area away from the pole column area is consistent with the extending direction of the second tab area away from the pole column area, and the width of the second tab area also gradually decreases along the direction from the first end to the second end; one multi-layer tab of the battery cell assembly is welded to one side of the first tab area away from the second tab area by side welding or edge welding, and another multi-layer tab of the battery cell assembly is welded to one side of the second tab area away from the first tab area by side welding or edge welding.

8. A battery pack, characterized by, The connecting sheet further comprises a second tab area connected with the pole column area, the extending direction of the first tab area away from the pole column area is consistent with the extending direction of the second tab area away from the pole column area, and the width of the second tab area also gradually decreases along the direction from the first end to the second end; one multi-layer tab of the battery cell assembly is welded to one side of the first tab area away from the second tab area by side welding or edge welding, and another multi-layer tab of the battery cell assembly is welded to one side of the second tab area away from the first tab area by side welding or edge welding.

Images