Secondary battery and battery pack

Abstract

The embodiment of the utility model provides a secondary battery and a battery pack, and relates to the field of batteries. The secondary battery comprises a first naked battery cell group, and the first naked battery cell group comprises a first naked battery cell and a second naked battery cell. Each of the first naked battery cell and the second naked battery cell comprises a first tab cluster. The first tab clusters of the first naked battery cell and the first tab clusters of the second naked battery cell are arranged in a staggered manner in the length direction and have the same polarity. The staggered arrangement of the first tab clusters can reduce the space occupancy rate in the height mode.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and more specifically, to a secondary battery and battery pack. Background Art

[0002] Secondary batteries, also known as rechargeable batteries or storage batteries, are batteries that can be recharged to activate the active materials after being discharged, allowing them to continue to be used.

[0003] With the development of rechargeable batteries and the increasing capacity requirements, the number of bare cells in a single battery cell has increased. However, the increased number of bare cells leads to an increase in the thickness of the tabs after they are folded up. This requires more height space after connecting to the adapter plate to ensure safety and ease of installation, but it also reduces the space utilization rate of the battery in the height direction. Utility Model Content

[0004] The purpose of this invention is to provide a secondary battery and battery pack that can achieve a large capacity for a single secondary battery while reducing the space utilization rate of the secondary battery in the vertical direction.

[0005] The embodiments of this utility model can be implemented as follows:

[0006] This application provides a secondary battery, which includes a first bare cell group, the first bare cell group including a first bare cell and a second bare cell;

[0007] Both the first bare cell and the second bare cell include a first tab cluster;

[0008] The first tab cluster of the first bare cell and the first tab cluster of the second bare cell are staggered in the length direction and have the same polarity.

[0009] In an optional embodiment, the secondary battery further includes a second bare cell assembly;

[0010] The second bare cell assembly includes a third bare cell and a fourth bare cell;

[0011] In the thickness direction, the first bare cell, the second bare cell, the third bare cell and the fourth bare cell are arranged sequentially, and the third bare cell and the second bare cell have symmetrical structures, and the fourth bare cell and the first bare cell have symmetrical structures.

[0012] In an optional embodiment, in the length direction, the first tab cluster of the second bare cell is disposed inside the first tab cluster of the first bare cell.

[0013] In an optional embodiment, in the thickness direction, the first tab cluster of the first bare cell and the first tab cluster of the second bare cell are arranged adjacent to each other.

[0014] In an optional embodiment, the secondary battery includes a first adapter plate and a first terminal post;

[0015] The first adapter plate has a first pole post connection portion and multiple first pole tab connection portions;

[0016] The first pole post connecting part is connected to the first pole post; the first pole tab connecting part and the first pole tab cluster are connected in a one-to-one correspondence;

[0017] Along the length direction, at least two of the plurality of first electrode tab connecting portions are respectively disposed on both sides of the first electrode post connecting portion.

[0018] In an optional embodiment, where the secondary battery comprises a first bare cell group and a second bare cell group,

[0019] In the thickness direction, the two sides of the first adapter piece are symmetrical.

[0020] In an optional embodiment, the number of the first electrode tab connectors is four; and / or,

[0021] Both the first bare cell and the second bare cell are made by winding electrode sheets.

[0022] In an optional implementation, the polarity of the first electrode cluster is either positive or negative.

[0023] Both the first bare cell and the second bare cell further include a second tab cluster; the first tab cluster and the second tab cluster have opposite polarities.

[0024] In an optional embodiment, the first tab cluster is bent and connected to the bottom wall of the first adapter piece;

[0025] And / or,

[0026] The first adapter plate has weight reduction grooves on all four sides.

[0027] Secondly, this application provides a battery pack, including a housing and a secondary battery as described in any of the above claims;

[0028] Multiple secondary batteries are housed within the casing and connected in series and / or parallel via connecting bars. The beneficial effects of the secondary battery and battery pack provided by this embodiment of the invention include:

[0029] This application achieves this by staggering the first tab clusters of the same polarity in the length direction of the first and second bare cells. This allows the two first tab clusters to be connected to the adapter plate in a staggered manner during connection, eliminating the need for stacking. This saves space in the height direction of the secondary battery. Furthermore, since the first tab clusters do not need to be stacked, the thickness of each individual first tab cluster is reduced, which improves welding quality and reduces defects. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the secondary battery structure provided in this embodiment;

[0032] Figure 2 This is a schematic diagram of the explosion of the secondary battery provided in this embodiment;

[0033] Figure 3 This is a schematic diagram showing the connection between the bare cell of the secondary battery provided in this embodiment and the first and second adapter pieces;

[0034] Figure 4 Figure 3 Enlarged view of point A in the middle;

[0035] Figure 5 Figure 3 Enlarged view of point B in the middle;

[0036] Figure 6 This is a schematic diagram of the cell module structure of the secondary battery provided in this embodiment;

[0037] Figure 7 This is a schematic diagram of the structure of the first adapter piece of the secondary battery provided in this embodiment;

[0038] Figure 8 This is a schematic diagram of the structure of the second adapter piece of the secondary battery provided in this embodiment.

[0039] Icons: 100 - Secondary battery; 101 - First tab cluster; 102 - Second tab cluster; 103 - First terminal; 104 - Second terminal; 110 - Housing; 111 - Receptacle; 130 - Cell module; 131 - Bare cell assembly; 133 - Bare cell; 135 - Positive tab cluster; 137 - Negative tab cluster; 139 - First bare cell assembly; 141 - Second bare cell assembly; 143 - First bare cell; 145 - Second bare cell; 147 - Third bare cell; 149 - Fourth bare cell; 150 - First adapter piece; 151 - First terminal connection; 153 - First tab connection; 155 - Weight reduction groove; 170 - Second adapter piece; 171 - Second terminal connection; 173 - Second tab connection; 190 - Top cover plate; 191 - Positive terminal; 193 - Negative terminal. DETAILED DESCRIPTION

[0040] With the development of rechargeable batteries and the increasing capacity requirements, the number of bare cells in a single battery cell has increased. However, the increased number of bare cells leads to an increase in the thickness of the tabs after they are folded up. This requires more height space after connecting to the adapter plate to ensure safety and ease of installation, but it also reduces the space utilization rate of the battery in the height direction.

[0041] To address the aforementioned problems, this utility model provides a secondary battery that, while achieving a single secondary battery capacity of 100, also reduces the space utilization rate of the secondary battery in the vertical direction.

[0042] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0044] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0045] In the description of this utility model, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the utility model product is usually placed during use, they are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0046] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0047] It should be noted that, where there is no conflict, the features in the embodiments of this utility model can be combined with each other.

[0048] This embodiment provides a battery pack (not shown in the figure) that can be used in new energy vehicles to provide power. Furthermore, this battery pack can also be used in energy storage and other fields.

[0049] Please refer to Figures 1 to 8 The battery pack includes a housing and multiple secondary batteries 100 disposed within the housing. The multiple secondary batteries 100 are connected in series and / or in parallel via connecting bars.

[0050] In this embodiment, the secondary battery 100 includes a first bare cell group 139. The first bare cell group 139 includes a first bare cell 143 and a second bare cell 145. Both the first bare cell 143 and the second bare cell 145 include a first tab cluster 101. The first tab clusters 101 of the first bare cell 143 and the first tab clusters 101 of the second bare cell 145 are staggered in the length direction and have the same polarity.

[0051] In this embodiment, the first tab clusters 101 of the same polarity in the first bare cell 143 and the second bare cell 145 are staggered in the length direction. This allows the two first tab clusters 101 to be connected to the adapter plate in a staggered manner during connection, eliminating the need for stacking. This saves space in the height direction of the secondary battery 100. Furthermore, since the first tab clusters 101 do not need to be stacked, the thickness of each individual first tab cluster 101 is reduced, which improves welding quality and reduces defects.

[0052] It should be noted that the length direction is AB in the diagram, while the width direction is CD. "Inside" and "outside" are relative concepts; the center of the secondary battery 100 is considered "inside," and the outer edge is considered "outside."

[0053] Please refer to Figures 1 to 8In this embodiment, the secondary battery 100 further includes a second bare cell group 141. The second bare cell group 141 includes a third bare cell 147 and a fourth bare cell 149. In the thickness direction, the first bare cell 143, the second bare cell 145, the third bare cell 147, and the fourth bare cell 149 are arranged sequentially, and the structures of the third bare cell 147 and the second bare cell 145 are symmetrical, and the structures of the fourth bare cell 149 and the first bare cell 143 are symmetrical.

[0054] In this embodiment, the structures of the third bare cell 147 and the second bare cell 145 are symmetrically arranged, and the structures of the fourth bare cell 149 and the first bare cell 143 are symmetrically arranged, which facilitates the welding of the tab cluster.

[0055] In this embodiment, in the length direction, the first tab cluster 101 of the second bare cell 145 is disposed inside the first tab cluster 101 of the first bare cell 143.

[0056] The different positions of the first bare cell 143, the second bare cell 145, the third bare cell 147, and the fourth bare cell 149 result in differences in their heat dissipation. The first bare cell 143 and the fourth bare cell 149, located on the outer side, have relatively better heat dissipation, while the second bare cell 145 and the third bare cell 147, located on the inner side, have relatively poor heat dissipation. In this embodiment, the first tab cluster 101 of the second bare cell 145 is located inside the first tab cluster 101 of the first bare cell 143. This change in the position of the tab cluster reduces the heat generation of the second bare cell 145 and the third bare cell 147, thereby improving the safety of the secondary battery 100.

[0057] Please refer to Figures 1 to 8 In this embodiment, in the thickness direction, the first tab cluster 101 of the first bare cell 143 and the first tab cluster 101 of the second bare cell 145 are arranged adjacent to each other.

[0058] In this embodiment, the first tab clusters 101 of the two bare cells 133 are arranged close together, which facilitates connection with the adapter plate.

[0059] Please refer to Figures 1 to 8 In this embodiment, the secondary battery 100 includes a first adapter piece 150 and a first terminal post 103. The first adapter piece 150 has a first terminal post connecting portion 151 and a plurality of first electrode tab connecting portions 153. The first terminal post connecting portion 151 is connected to the first terminal post 103; the first electrode tab connecting portions 153 and the first electrode tab clusters 101 are connected one-to-one. In the length direction, at least two of the plurality of first electrode tab connecting portions 153 are respectively disposed on both sides of the first terminal post connecting portion 151.

[0060] In this embodiment, the welding of the first tab cluster 101 can be conveniently achieved through the above method.

[0061] In this embodiment, the two sides of the first adapter piece 150 are symmetrical in the thickness direction. That is, the first adapter piece 150 is symmetrically arranged in the width direction.

[0062] In this embodiment, there are four first electrode connection portions 153. Providing four first electrode connection portions 153 allows the first electrode clusters 101 of the first bare cell 143, the second bare cell 145, the third bare cell 147, and the fourth bare cell 149 to be connected one-to-one to the first electrode connection portions 151.

[0063] In this embodiment, the first bare cell 143, the second bare cell 145, the third bare cell 147 and the fourth bare cell 149 are all made by winding electrode sheets.

[0064] In this embodiment, the first tab cluster 101 is either positive or negative, and both the first bare cell 143 and the second bare cell 145 further include a second tab cluster 102; the first tab cluster 101 and the second tab cluster 102 have opposite polarities. The first tab cluster 101 is bent and connected to the bottom wall of the first adapter piece 150. Weight reduction grooves 155 are provided around the first adapter piece 150.

[0065] Please refer to Figures 1 to 8 The first bare cell 143, the second bare cell 145, the third bare cell 147, and the fourth bare cell 149 are four bare cells 133 of the cell module 130 of the secondary battery 100. Specifically, the first bare cell 143 and the second bare cell 145 form one bare cell group 131, and the third bare cell 147 and the fourth bare cell 149 form another bare cell group 131. The first tab cluster 101 is the positive electrode tab cluster 135, the second tab cluster 102 is the negative electrode tab cluster 137, the first terminal 103 is the positive terminal, and the second terminal 104 is the negative terminal. Please refer to [the provided text]. Figures 1 to 8In this embodiment, the secondary battery 100 includes a housing 110, a cell module 130, a first adapter 150, a second adapter 170, and a top cover 190. The housing 110 is provided with an accommodating cavity 111. The cell module 130 includes at least two sets of bare cell groups 131, each set of bare cell groups 131 including at least two bare cells 133. Each bare cell 133 has at least one positive electrode tab cluster 135 and at least one negative electrode tab cluster 137. The positive electrode tab clusters 135 of all bare cells 133 in the same bare cell group 131 are staggered. The negative electrode tab clusters 137 of all bare cells 133 in the same bare cell group 131 are staggered. The top cover 190 is provided with a positive terminal post 191 and a negative terminal post 193. The first adapter 150 is connected to the inner side of the positive terminal post 191. The second adapter plate 170 is connected to the inner side of the negative terminal 193. The cell module 130 is disposed in the accommodating cavity 111, and the top cover plate 190 is installed in the opening of the housing 110. The positive electrode tabs 135 of all bare cells 133 are misaligned and connected to the first adapter plate 150, and the negative electrode tabs 137 of all bare cells 133 are misaligned and connected to the second adapter plate 170.

[0066] The secondary battery 100 provided in this embodiment has at least four bare cells 133, which allows for a larger capacity of a single secondary battery 100. Furthermore, this application also arranges the positive electrode tabs 135 of all bare cells 133 in the same bare cell group 131 to be staggered, and the negative electrode tabs 137 of all bare cells 133 in the same bare cell group 131 to be staggered. This allows the positive electrode tabs 135 of all bare cells 133 to be staggeredly connected to the first adapter plate 150, and the negative electrode tabs 137 of all bare cells 133 to be staggeredly connected to the second adapter plate 170. This separate connection method fully utilizes horizontal space, eliminating the need for all positive electrode tabs 135 and all negative electrode tabs 137 to be stacked together. The thickness of a single positive electrode tab 135 or a single negative electrode tab 137 is smaller, thereby improving the space utilization of the secondary battery 100 in the vertical direction. For the same capacity, the secondary battery 100 provided in this application has a lower height. Secondly, reducing the thickness of the positive electrode tab cluster 135 and the negative electrode tab cluster 137 can improve the welding yield.

[0067] In existing secondary batteries 100, all bare cells 133 installed inside the casing have the same structure, meaning the tabs are in the same position. When welding to the adapter plate, to facilitate welding, the positive tabs of several bare cells 133 on the same side are typically folded upwards together before welding. Since the thickness increases after the tabs are folded and stacked, a larger space needs to be reserved in the height direction during design, thus increasing the overall height. In this application, because the bare cells 133 have different specifications, i.e., the tab positions are different, this arrangement can fully utilize the planar space, and the height dimension of the secondary battery 100 with two bare cells 133 does not need to be increased compared to existing designs.

[0068] It should be noted that the positive electrode tab cluster 135 is formed by gathering and stacking the positive electrode tabs of the bare cell 133 together to form a cluster-like structure. The negative electrode tab cluster 137 is formed by gathering and stacking the negative electrode tabs of the bare cell 133 together to form a cluster-like structure.

[0069] Please refer to Figures 1 to 8 In this embodiment, the first adapter piece 150 includes a first terminal connection portion 151 and a plurality of first electrode tab connection portions 153 disposed around the periphery of the first terminal connection portion 151. The first terminal connection portion 151 is connected to the positive terminal 191. The plurality of first electrode tab connection portions 153 are disposed one-to-one with the positive electrode tab clusters 135 of all bare cells 133. The positive electrode tab clusters 135 of all bare cells 133 are connected one-to-one with the first electrode tab connection portion 153.

[0070] In this embodiment, the first adapter piece 150 is configured as a first pole post connection part 151 and a plurality of first pole tab connection parts 153, which is beneficial for the plurality of positive pole tab clusters 135 to be connected one-to-one to the plurality of first pole tab connection parts 153.

[0071] In this embodiment, the battery module 130 includes two sets of bare battery cell groups 131, each set of bare battery cell groups 131 includes two bare battery cells 133, and each bare battery cell 133 is provided with a positive electrode tab cluster 135. The first electrode tab connection part 153 includes four parts, and the four first electrode tab connection parts 153 are connected to the first electrode post connection part 151.

[0072] In this embodiment, the bare cell group 131 is configured into two groups, and each group of bare cell group 131 is configured with two groups of bare cells 133. This can increase the capacity of the secondary battery 100 and facilitate connection.

[0073] Please refer to Figures 1 to 8Specifically, the two bare cells 133 located in the same bare cell group 131 are different. The specific difference lies in the position of their tabs. For example, the two bare cell groups 131 are a first bare cell group 139 and a second bare cell group 141. The first bare cell group 139 includes a first bare cell 143 and a second bare cell 145, while the second bare cell group 141 includes a third bare cell 147 and a fourth bare cell 149. The first bare cell 143, the second bare cell 145, the third bare cell 147, and the fourth bare cell 149 are sequentially arranged within the receiving cavity 111 along the width direction of the housing 110. The first bare cell 143 and the fourth bare cell 149 have the same structure; that is, the positive and negative tabs of the first bare cell 143 and the fourth bare cell 149 extend at the same position in the length direction. The positive and negative tabs of the second bare cell 145 and the third bare cell 147 extend at the same position along their length. The positive and negative tabs of the first bare cell 143 and the second bare cell 145 extend at staggered positions along their length. The positive and negative tabs of the third bare cell 147 and the fourth bare cell 149 extend at staggered positions along their length. This arrangement allows for the production of four bare cells 133 using only two specifications, simplifying manufacturing. Furthermore, this design results in shorter tabs on the inner side of the second bare cell 145 and the third bare cell 147, leading to lower resistance and less heat generation. Conversely, the outer tabs on the first bare cell 143 and the fourth bare cell 149 are longer, resulting in higher resistance and more heat generation, but heat dissipation is also faster, especially for the outermost cells, preventing heat concentration.

[0074] Of course, in other embodiments of this application, the protruding positions of the positive and negative tabs of the first bare cell 143, the second bare cell 145, the third bare cell 147 and the fourth bare cell 149 may all be different in the length direction.

[0075] In this embodiment, the positive electrode tab clusters 135 of the two bare cells 133 of each bare cell group 131 are connected to the two first electrode tab connection portions 153 on the same side of the width direction of the first adapter piece 150.

[0076] In this embodiment, the positive electrode tab clusters 135 of two bare cells 133 located in the same bare cell group 131 are connected to the same side in the width direction of the first adapter piece 150, which can shorten the length of the tabs and facilitate assembly.

[0077] Please refer to Figures 1 to 8 In this embodiment, the first adapter piece 150 has a centrally symmetrical structure, and the positive electrode post 191 is connected to the center of the first adapter piece 150. The four first electrode tabs 153 are located at the four corners of the first adapter piece 150. Thus, the positive electrode tab clusters 135 of the two bare cells 133 located in the same bare cell group 131 are located on both sides of the positive electrode post 191.

[0078] In some embodiments of this application, the first adapter piece 150 may be rectangular, square, or the like. Of course, in other embodiments of this application, the first adapter piece 150 may also be in other shapes.

[0079] Please refer to Figures 1 to 8 In this embodiment, the positive electrode tab cluster 135 of the second bare cell 145 and the positive electrode tab cluster 135 of the third bare cell 147 are respectively connected to the two first electrode tab connection portions 153 located outside the first terminal post connection portion 151 of the first adapter piece 150. The positive electrode tab cluster 135 of the first bare cell 143 and the positive electrode tab cluster 135 of the fourth bare cell 149 are respectively connected to the two first electrode tab connection portions 153 located inside the first terminal post connection portion 151 of the first adapter piece 150. The positive electrode tab cluster 135 is connected to the first electrode tab connection portion 153 by bending the positive electrode tab cluster 135 into a "7" shape and connecting it to the bottom wall of the first electrode tab connection portion 153.

[0080] In this embodiment, the first adapter piece 150 is provided with weight-reducing grooves 155, which are located at the center of the four sides of the first adapter piece 150 and extend parallel to the center to form four strip-shaped weight-reducing grooves 155. Of course, in other embodiments of this application, the location and shape of the weight-reducing grooves 155 can also be specifically designed according to the current flow and other conditions.

[0081] Please refer to Figures 1 to 8 In this embodiment, the shape of the second adapter piece 170 is substantially the same as that of the first adapter piece 150. One of the second adapter piece 170 and the first adapter piece 150 is made of aluminum and the other is made of copper.

[0082] Specifically, the second adapter piece 170 includes a second terminal connection portion 171 and a plurality of second electrode tab connection portions 173 disposed around the second terminal connection portion 171. The second terminal connection portion 171 is connected to the negative terminal 193. The plurality of second electrode tab connection portions 173 are respectively disposed corresponding to the negative electrode tab clusters 137 of all bare cells 133. The negative electrode tab clusters 137 of all bare cells 133 are respectively connected to the second electrode tab connection portions 173.

[0083] Please refer to Figures 1 to 8 In this embodiment, the second adapter piece 170 is configured as a second pole post connection part 171 and a plurality of second pole tab connection parts 173, which is beneficial for the plurality of negative pole tab clusters 137 to be connected one-to-one to the plurality of second pole tab connection parts 173.

[0084] Specifically, the first bare cell 143, the second bare cell 145, the third bare cell 147, and the fourth bare cell 149 are each provided with a negative electrode tab cluster 137. There are four second electrode tab connection portions 173, which are connected to the second terminal post connection portion 171. The negative electrode tab clusters 137 of the two bare cells 133 in each bare cell group 131 are connected to two second electrode tab connection portions 173 on the same side of the width direction of the second adapter piece 170.

[0085] The negative electrode tab cluster 137 of the second bare cell 145 and the negative electrode tab cluster 137 of the third bare cell 147 are respectively connected to the two second electrode tab connection portions 173 located outside the second pole post connection portion 171 of the second adapter piece 170. The negative electrode tab cluster 137 of the first bare cell 143 and the negative electrode tab cluster 137 of the fourth bare cell 149 are respectively connected to the two second electrode tab connection portions 173 located inside the second pole post connection portion 171 of the second adapter piece 170. The negative electrode tab cluster 137 is connected to the first electrode tab connection portion 153 by bending the negative electrode tab cluster 137 into a "7" shape and connecting it to the bottom wall of the second electrode tab connection portion 173.

[0086] In this embodiment, the second adapter piece 170 has a centrally symmetrical structure, and the negative terminal 193 is connected to the center of the second adapter piece 170.

[0087] In some embodiments of this application, the first adapter piece 150 may be rectangular, square, or the like. Of course, in other embodiments of this application, the first adapter piece 150 may also be in other shapes.

[0088] In this embodiment, the second adapter piece 170 is provided with weight-reducing grooves 155, which are located at the center of the four sides of the second adapter piece 170 and extend parallel to the center to form four strip-shaped weight-reducing grooves 155. Of course, in other embodiments of this application, the location and shape of the weight-reducing grooves 155 can also be specifically designed according to the current flow and other conditions.

[0089] Secondly, in some other embodiments of this application, the secondary battery 100 can also be used alone to power an electrical device.

[0090] In summary, the working principle and beneficial effects of the secondary battery 100 and battery pack provided in this embodiment include:

[0091] The secondary battery 100 provided in this embodiment has at least four bare cells 133, which allows for a larger capacity of a single secondary battery 100. Secondly, this embodiment also arranges the positive electrode tabs 135 of all bare cells 133 in the same bare cell group 131 to be staggered, and the negative electrode tabs 137 of all bare cells 133 in the same bare cell group 131 to be staggered. This allows the positive electrode tabs 135 of all bare cells 133 to be staggered and connected to the first adapter plate 150, and the negative electrode tabs 137 of all bare cells 133 to be staggered and connected to the second adapter plate 170. This separate connection method fully utilizes horizontal space, eliminating the need for all positive electrode tabs 135 and all negative electrode tabs 137 to be stacked together. The thickness of a single positive electrode tab 135 or a single negative electrode tab 137 is smaller, thereby improving the space utilization of the secondary battery 100 in the vertical direction. For the same capacity, the secondary battery 100 provided in this application has a lower height.

[0092] The above are merely specific embodiments of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model.

Claims

1. A secondary battery, characterized in that, It includes a first bare cell group (139), which includes a first bare cell (143) and a second bare cell (145); Both the first bare cell (143) and the second bare cell (145) include a first tab cluster (101); The first tab cluster (101) of the first bare cell (143) and the first tab cluster (101) of the second bare cell (145) are staggered in the length direction and have the same polarity.

2. The secondary battery according to claim 1, characterized in that, It also includes a second bare cell assembly (141); The second bare cell group (141) includes a third bare cell (147) and a fourth bare cell (149); In the thickness direction, the first bare cell (143), the second bare cell (145), the third bare cell (147) and the fourth bare cell (149) are arranged in sequence, and the third bare cell (147) and the second bare cell (145) are symmetrical in structure, and the fourth bare cell (149) and the first bare cell (143) are symmetrical in structure.

3. The secondary battery according to claim 2, characterized in that, In the length direction, the first tab cluster (101) of the second bare cell (145) is disposed inside the first tab cluster (101) of the first bare cell (143).

4. The secondary battery according to any one of claims 1 to 3, characterized in that, In the thickness direction, the first tab cluster (101) of the first bare cell (143) and the first tab cluster (101) of the second bare cell (145) are arranged adjacent to each other.

5. The secondary battery according to any one of claims 1 to 3, characterized in that, The secondary battery includes a first adapter piece (150) and a first terminal (103). The first adapter piece (150) has a first pole post connection portion (151) and a plurality of first pole tab connection portions (153); The first pole post connecting part (151) is connected to the first pole post (103); the first pole tab connecting part (153) and the first pole tab cluster (101) are connected one-to-one; In the length direction, at least two of the plurality of first electrode tab connecting portions (153) are respectively disposed on both sides of the first electrode post connecting portion (151).

6. The secondary battery according to claim 5, characterized in that, In the case that the secondary battery includes a first bare cell group (139) and a second bare cell group (141), In the thickness direction, the two sides of the first adapter piece (150) are symmetrical.

7. The secondary battery according to claim 5, characterized in that, The number of the first electrode connecting parts (153) is four; and / or, Both the first bare cell (143) and the second bare cell (145) are made by winding electrode sheets.

8. The secondary battery according to any one of claims 1 to 3, characterized in that, The polarity of the first anode cluster (101) is either positive or negative; Both the first bare cell (143) and the second bare cell (145) further include a second tab cluster (102); The first ear cluster (101) and the second ear cluster (102) have opposite polarities.

9. The secondary battery according to claim 5, characterized in that, The first tab cluster (101) is bent and connected to the bottom wall of the first adapter piece (150); and / or, The first adapter plate (150) is provided with weight reduction grooves (155) on all four sides.

10. A battery pack, characterized in that, Includes a housing and a plurality of secondary batteries as described in any one of claims 1-9; Multiple secondary batteries are housed inside the casing and connected in series and / or in parallel via connecting bars.

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