A battery pack and energy storage device

Abstract

This utility model discloses a battery pack and energy storage device. In the battery pack, the casing has a receiving space, and battery cell assemblies are disposed within the receiving space. A first battery cell assembly and a second battery cell assembly are arranged along a first direction. A first circuit board is connected to the first battery cell assembly, and a second circuit board is connected to the second battery cell assembly. The first and second circuit boards are located on the same side of the battery cell assemblies. A first busbar is disposed on the first circuit board and includes a first fixing part and a first welding part. The first fixing part protrudes from the first welding part. A second busbar is disposed on the second circuit board. A connector is fixed to the first fixing part by a first fastener, and the connector connects the first and second busbars. This method helps reduce the loosening of the connector due to material fatigue, thermal expansion and contraction, or vibration, improves the connection strength between the connector and the first busbar, and enhances the electrical performance and safety of the battery pack.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery pack and energy storage device. Background Technology

[0002] A battery pack is a device that can store and release electrical energy. A battery pack typically includes multiple sets of arranged battery cells and multiple circuit boards corresponding to the sets of battery cells. The busbars of the multiple circuit boards are usually connected by connectors (e.g., copper busbars) to achieve electrical interconnection between the battery cells.

[0003] Currently, the busbars and connectors of battery packs are typically fixed together using methods such as welding or bonding. However, during long-term use, factors such as material fatigue, thermal expansion and contraction, or vibration can lead to insufficient connection strength between the busbars and connectors, resulting in a decline in the electrical performance and safety of the battery pack. Utility Model Content

[0004] The present invention aims to provide a battery pack and energy storage device that can overcome or at least partially solve the above problems.

[0005] To solve the above-mentioned technical problems, one technical solution adopted in this utility model embodiment is: providing a battery pack, including a housing, a cell assembly, a first circuit board, a second circuit board, a first busbar, a second busbar, and a connector. The housing is provided with a receiving space, the cell assembly is disposed in the receiving space, the cell assembly includes a first cell assembly and a second cell assembly, the first cell assembly and the second cell assembly are arranged along a first direction, the first circuit board is connected to the first cell assembly, the second circuit board is connected to the second cell assembly, the first circuit board and the second circuit board are located on the same side of the cell assembly, the first busbar is disposed on the first circuit board, the first busbar includes a first fixing part and a first welding part, the first fixing part protrudes from the first welding part, the second busbar is disposed on the second circuit board, and the connector is fixed to the first fixing part by a first fastener, the connector connects the first busbar and the second busbar.

[0006] In one or more of the above optional embodiments, the first battery cell assembly includes a plurality of first battery cells, and at least one of the tabs of the first battery cell is laminated and welded to a first welding portion, wherein both the tabs of the first battery cell and the first welding portion are located below the connector.

[0007] In one or more of the above optional embodiments, the second busbar includes a second fixing part and a second welding part, the second fixing part protruding from the second welding part, and the connector and the second fixing part being fixed by a second fastener.

[0008] In one or more of the above optional embodiments, the second battery cell assembly includes a plurality of second batteries, at least one of the tabs of the second battery cell being laminated and welded to a second welding portion, wherein both the tabs of the second battery cell and the second welding portion are located below the connector.

[0009] In one or more of the above optional embodiments, a plurality of first cells are arranged along a first direction, a plurality of second cells are arranged along a first direction, the battery pack includes a first electrode portion and a second electrode portion, the polarities of the first electrode portion and the second electrode portion are opposite, the first electrode portion is connected to the first cell among the plurality of first cells that is farthest from the connector, and the second electrode portion is connected to the second cell among the plurality of second cells that is farthest from the connector.

[0010] In one or more of the above optional embodiments, the battery pack includes a third busbar disposed on the first circuit board. The third busbar includes a third fixing part and a third welding part. The third fixing part protrudes from the third welding part. The first electrode part is fixed to the third fixing part by a third fastener. The tab of the first cell farthest from the connector is laminated and welded to the third welding part. The tab of the first cell and the first electrode part do not overlap.

[0011] In one or more of the above optional embodiments, the battery pack includes a fourth busbar disposed on the second circuit board. The fourth busbar includes a fourth fixing part and a fourth welding part. The fourth fixing part protrudes from the fourth welding part. The second electrode part and the fourth fixing part are fixed by a third fastener. The tab of the second cell farthest from the connector is laminated and welded to the fourth welding part. The tab of the second cell and the fourth welding part are both located below the second electrode part.

[0012] In one or more of the above optional embodiments, the first circuit board is provided with a first opening, and the tabs of the other first cells pass through the first opening and are soldered to the first circuit board.

[0013] In one or more of the above optional embodiments, the second circuit board is provided with a second opening, and the tabs of the other second cells pass through the second opening and are soldered to the second circuit board.

[0014] To solve the above-mentioned technical problems, another technical solution adopted in this utility model embodiment is to provide an energy storage device, including the above-mentioned battery pack.

[0015] The beneficial effects of this utility model embodiment are as follows: Unlike the prior art, this utility model embodiment provides a battery pack, including a housing, a cell assembly, a first circuit board, a second circuit board, a first busbar, a second busbar, and a connector. The housing is provided with a receiving space, and the cell assembly is disposed in the receiving space. The cell assembly includes a first cell assembly and a second cell assembly, which are arranged along a first direction of the cell assembly. The first circuit board is connected to the first cell assembly, and the second circuit board is connected to the second cell assembly. The first circuit board and the second circuit board are located on the same side of the cell assembly. The first busbar is disposed on the first circuit board and includes a first fixing part and a first welding part. The first fixing part protrudes from the first welding part. The second busbar is disposed on the second circuit board. The connector is fixed to the first fixing part by a first fastener, and the connector connects the first busbar and the second busbar. In the above manner, the connector and the first busbar in this embodiment of the present invention are fixed by the first fastener, which helps to reduce the loosening of the connector caused by factors such as material fatigue, thermal expansion and contraction or vibration, improve the connection between the connector and the first busbar, improve the overall structural stability of the battery pack, and improve the electrical performance and safety of the battery pack. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the specific embodiments of this utility model or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to actual scale.

[0017] Figure 1 This is a schematic diagram of the overall structure of the battery pack provided in this embodiment of the utility model;

[0018] Figure 2 This is a partial structural diagram of the battery pack provided in this embodiment of the utility model. Figure 1 ;

[0019] Figure 3 This is a partial structural diagram of the battery pack provided in this embodiment of the utility model. Figure 2 ;

[0020] Figure 4 This is a partial structural diagram of the battery pack provided in this embodiment of the utility model. Figure 3 ;

[0021] Figure 5 This is a partial structural diagram of the battery pack provided in this embodiment of the utility model. Figure 4 ;

[0022] Figure 6 This is a partial structural diagram of the battery pack provided in this embodiment of the utility model.Figure 5 ;

[0023] Figure 7 This is a partial structural diagram of the battery pack provided in this embodiment of the utility model. Figure 6 ;

[0024] Figure 8 This is a schematic diagram of the first busbar structure of the battery pack provided in this embodiment of the utility model.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Shell;

[0027] 2. Battery cell assembly, 21. First battery cell assembly, 211. First battery cell, 2111. First sub-battery cell, 22. Second battery cell assembly, 221. Second battery cell, 2211. Second sub-battery cell;

[0028] 3. First circuit board; 31. First opening; 32. First conductive element;

[0029] 4. Second circuit board; 41. Second opening; 42. Second conductive element;

[0030] 51 First busbar, 511 First fixing part, 512 First welding part, 513 First plate, 514 Second plate, 515 Third plate, 516 Fourth plate, 52 Second busbar, 521 Second fixing part, 522 Second welding part, 53 Third busbar, 531 Third fixing part, 532 Third welding part, 54 Fourth busbar, 541 Fourth fixing part, 542 Fourth welding part;

[0031] 6 connectors;

[0032] 7. First electrode section;

[0033] 8. Second electrode section;

[0034] 91 First fastener, 92 Second fastener, 93 Third fastener, 94 Fourth fastener;

[0035] X is the first direction;

[0036] 100 battery pack. Detailed Implementation

[0037] To facilitate understanding of this utility model, a more detailed description is provided below with reference to the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as "connected" to another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "upper," "lower," "inner," "outer," "vertical," "horizontal," etc., used in this specification indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0038] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items.

[0039] Please see Figures 1 to 4 This utility model provides an embodiment of a battery pack 100, which includes a housing 1 and a cell assembly 2. The housing 1 is provided with a receiving space, and the cell assembly 2 is disposed in the receiving space.

[0040] In some embodiments, the battery cell assembly 2 includes a first battery cell assembly 21 and a second battery cell assembly 22, the first battery cell assembly 21 and the second battery cell assembly 22 being arranged along a first direction X.

[0041] In some embodiments, the first direction X is the thickness direction of the battery cell, which is beneficial for the arrangement of the battery cell assembly 2.

[0042] In some embodiments, the battery pack 100 includes a first circuit board 3 and a second circuit board 4. The first circuit board 3 is connected to the first cell assembly 21, and the second circuit board 4 is connected to the second cell assembly 22. The first circuit board 3 and the second circuit board 4 are located on the same side of the cell assembly 2.

[0043] In some embodiments, the battery pack 100 includes a first busbar 51, a second busbar 52, and a connector 6. The first busbar 51 is disposed on a first circuit board 3 and includes a first fixing portion 511 and a first welding portion 512. The first fixing portion 511 protrudes from the first welding portion 512. The second busbar 52 is disposed on a second circuit board 4. The connector 6 is fixed to the first fixing portion 511 by a first fastener 91, and the connector 6 connects the first busbar 51 and the second busbar 52. The first fixing portion 511 protrudes from the first welding portion 512, thereby raising the first fixing portion 511 relative to the first welding portion 512. The first welding portion 512 and the first fixing portion 511 form a single-layer stepped structure, providing the first fixing portion 511 with sufficient depth to provide the required depth when the connector 6 is fixed to the first fixing portion 511 by the first fastener 91.

[0044] In this manner, the connector 6 and the first busbar 51 are fixed together by the first fastener 91. This helps reduce the possibility of the connector 6 loosening due to material fatigue and thermal expansion and contraction, improves the connection strength between the connector 6 and the first busbar 51, enhances the overall structural stability of the battery pack 100, and improves the electrical performance and safety of the battery pack 100. Simultaneously, the connection between the connector 6 and the first busbar 51, secured by the first fastener 91, facilitates a detachable connection between them, making it convenient for the connector 6 to be installed, removed, maintained, and replaced.

[0045] In some embodiments, the first fastener 91 includes a screw, and both the first fixing part 511 and the connector 6 are provided with threaded holes. The first fastener 91 fixes the first fixing part 511 and the connector 6.

[0046] In some embodiments, please refer to Figure 3 and Figure 5 The first battery cell assembly 21 includes a plurality of first battery cells 211, each of which is provided with a tab 211a. At least one tab 211a of the first battery cell 211 is laminated and welded to the first welding part 512, such as... Figure 5 As shown, the tab 211a and the first welding part 512 of the first cell 211 are both located below the connector 6.

[0047] In some embodiments, such as Figure 3 and Figure 4 As shown, in the first cell assembly 21, two first cells 211 are connected in parallel and then in series. The tab of the outermost first cell 211 closest to the second cell assembly 22 is laminated and welded to the first welding part 512.

[0048] In some embodiments, the tab of the first cell 211 closest to the connector 6 is laminated and welded to the first welding part 512, and along the lamination direction, the tab of the first cell 211 closest to the connector 6, the first welding part 512, and the connector 6 overlap.

[0049] In the above manner, along the height direction of the first busbar 51, the first fixing part 511 is connected to the connector 6 above the first busbar 51, and the first welding part 512 is welded to the tab of the first battery cell 211 below the connector 6, so that the connector 6 and the tab of the first battery cell 211 are staggered along the height direction of the first busbar 51, reducing the probability of interference between the connector 6 and the tab of the first battery cell 211, and increasing the electrical clearance between the connector 6 and the tab of the first battery cell 211.

[0050] In some embodiments, please refer to Figure 3 and Figure 4 The second busbar 52 includes a second fixing portion 521 and a second welding portion 522. The second fixing portion 521 protrudes from the second welding portion 522. The connector 6 is fixed to the second fixing portion 521 by a second fastener 92. The connector 6 connects the first busbar 51 and the second busbar 52. The second fixing portion 521 protrudes from the second welding portion 522, raising the second fixing portion 521 relative to the second welding portion 522. The second welding portion 522 and the second fixing portion 521 form a single-layer stepped structure, providing the second fixing portion 521 with sufficient depth to provide the necessary depth for the connector 6 to be fixed to the second fixing portion 521 by the second fastener 521.

[0051] In this manner, the connector 6 and the second busbar 52 are fixed together by the second fastener 92. This helps reduce the loosening of the connector 6 due to material fatigue and thermal expansion and contraction, improves the connection strength between the connector 6 and the second busbar 52, further enhances the overall structural stability of the battery pack 100, and further improves the electrical performance and safety of the battery pack 100. Simultaneously, the fixing of the connector 6 and the second busbar 52 by the second fastener 92 facilitates a detachable connection between the connector 6 and the second busbar 52, making it convenient for the assembly and disassembly of the connector 6, as well as for its maintenance and replacement.

[0052] In some embodiments, the second fastener 92 includes a screw, and both the second fixing part 521 and the first connector 6 are provided with threaded holes. The first fastener 91 fixes the second fixing part 521 and the connector 6.

[0053] In some embodiments, please refer to Figure 3 and Figure 5The second battery cell assembly 22 includes a plurality of second battery cells 221, each of which is provided with a tab 221a. At least one tab 221a of the second battery cell 221 is laminated and welded to the second welding part 522, such as... Figure 5 As shown, the tab 221a of the second cell 221 and the second welding part 522 are both located below the connector 6.

[0054] In some embodiments, such as Figure 3 and Figure 4 As shown, the second cell assembly 22 consists of two second cells 221 connected in parallel and then in series. The tab of the outermost second cell 221 of the first cell assembly 21 is laminated and welded to the second welding part 522.

[0055] In some embodiments, the tab of the second cell 221 closest to the connector is laminated and welded to the second welding part 522, and along the lamination direction, the tab of the second cell 221 closest to the connector, the second welding part 522 and the connector 6 overlap.

[0056] In the above manner, along the height direction of the second busbar 52, the second fixing part 521 is connected to the connector 6 above the second busbar 52, and the second welding part 522 is welded to the tab of the second battery cell 221 below the connector 6. This allows the tabs of the connector 6 and the second battery cell 221 to be staggered along the height direction of the second busbar 52, reducing the probability of interference between the tabs of the connector 6 and the second battery cell 221 and increasing the electrical clearance between the tabs of the connector 6 and the second battery cell 221.

[0057] Please see Figure 2 and Figure 3 Multiple first cells 211 are arranged along a first direction of the first cell assembly 21, and multiple second cells 221 are arranged along a first direction of the second cell assembly 22. The battery pack 100 includes a first electrode portion 7 and a second electrode portion 8, with opposite polarities. The first electrode portion 7 is connected to the first cell 211 furthest from the connector 6 among the multiple first cells 211, and the second electrode portion 8 is connected to the second cell 221 furthest from the connector 6 among the multiple second cells 221. The first electrode portion 7, the first circuit board 3, the first busbar 51, the connector 6, the second busbar 52, the second circuit board 4, and the second electrode portion 8 are sequentially connected to form an electrical circuit. For example, the first electrode portion 7 serves as the overall positive electrode of the cell assembly 2, and the second electrode portion 8 serves as the overall negative electrode of the cell assembly 2.

[0058] In some embodiments, the battery pack 100 further includes a third circuit board (not shown), which is disposed on one side of the cell assembly 2. The end of the first electrode portion 7 away from the third busbar 53 is connected to the third circuit board, and the end of the second electrode portion 8 away from the fourth busbar 54 is connected to the third circuit board. The third circuit board is used for electrical connection with external electrical equipment.

[0059] In some embodiments, the first electrode portion 7 and the second electrode portion 8 are both copper busbars.

[0060] In some embodiments, please refer to Figure 3 and Figure 6 The battery pack 100 includes a third busbar 53 disposed on the first circuit board 3. The third busbar 53 includes a third fixing part 531 and a third welding part 532. The third fixing part 531 protrudes from the third welding part 532. The first electrode part 7 is fixed to the third fixing part 531 by a third fastener 93. The tab of the first cell 211, which is furthest from the connector 6, is laminated and welded to the third welding part 532. Figure 6 As shown, the tabs of the first cell 211 and the third welding part 532 do not overlap.

[0061] The third fixing part 531 protrudes from the third welding part 532, so that the third fixing part 531 is raised relative to the third welding part 532. The third welding part 532 and the third fixing part 531 form a single-layer stepped structure, so that the third fixing part 531 has a depth, providing the required depth when the first electrode part 7 and the third fixing part 531 are fixed by the third fastener 93.

[0062] In this manner, the first electrode portion 7 and the third busbar 53 are fixed together by the third fastener 93. This helps reduce the possibility of the first electrode portion 7 loosening due to material fatigue and thermal expansion and contraction, improves the connection strength between the first electrode portion 7 and the third busbar 53, further enhances the overall structural stability of the battery pack 100, and further improves the electrical performance and safety of the battery pack 100. Simultaneously, the fixing of the first electrode portion 7 and the third busbar 53 by the third fastener 93 facilitates a detachable connection between the first electrode portion 7 and the third busbar 53, making it convenient to disassemble and assemble the first electrode portion 7, and facilitating its maintenance and replacement.

[0063] In some embodiments, the third fastener 93 includes a screw, and both the first electrode portion 7 and the third fixing portion 531 are provided with threaded holes. The third fastener 93 connects the first electrode portion 7 and the connector 6.

[0064] Third fixing part 531.

[0065] In some embodiments, please refer to Figure 3 and Figure 7The battery pack 100 includes a fourth busbar 54 disposed on the second circuit board 4. The fourth busbar 54 includes a fourth fixing part 541 and a fourth welding part 542. The fourth fixing part 541 protrudes from the fourth welding part 542. The second electrode part 8 is fixed to the fourth fixing part 541 by a fourth fastener 94. The tab of the second cell 221, which is furthest from the connector 6, is laminated and welded to the fourth welding part 542. Figure 7 As shown, the tabs of the second cell 221 and the fourth welding part 542 are both located below the second electrode part 8.

[0066] The fourth fixing part 541 protrudes from the fourth welding part 542, so that the fourth fixing part 541 is raised relative to the fourth welding part 542. The fourth welding part 542 and the fourth fixing part 541 form a single-layer stepped structure so that the fourth fixing part 541 has a depth, providing the required depth when the second electrode part 8 and the fourth fixing part 541 are fixed by the fourth fastener 94.

[0067] In this manner, the second electrode portion 8 and the fourth busbar 54 are fixed together by the fourth fastener 94. This helps reduce the loosening of the second electrode portion 8 due to material fatigue and thermal expansion and contraction, improves the connection strength between the second electrode portion 8 and the fourth busbar 54, further enhances the overall structural stability of the battery pack 100, and further improves the electrical performance and safety of the battery pack 100. Simultaneously, the fixing of the second electrode portion 8 and the fourth busbar 54 by the fourth fastener 94 facilitates a detachable connection between the two, making it convenient to disassemble and assemble the second electrode portion 8, and facilitating its maintenance and replacement.

[0068] In some embodiments, the fourth fastener 94 includes a screw, and both the fourth fixing part 541 and the second electrode part 8 are provided with threaded holes. The fourth fastener 94 fixes the fourth fixing part 541 and the second electrode part 8.

[0069] In some embodiments, please refer to Figure 3 and Figure 8 The first busbar 51 includes a first plate 513, a second plate 514, a third plate 515, and a fourth plate 516 connected in sequence. The first plate 513 and the third plate 515 are symmetrically arranged about the second plate 514. The first plate 513, the second plate 514, and the third plate are arranged in a U-shape. The fourth plate 516 is located below the second plate 514 and extends in a direction away from the second plate 514. The first plate 513, the second plate 514, and the third plate 515 together constitute the first fixing part 511, and the fourth plate 516 constitutes the first welding part 512.

[0070] In some embodiments, the first circuit board 3 is provided with a plurality of first openings 31, and the tabs of other first cells 211 are soldered to the first circuit board 3 after passing through the plurality of first openings 31 one by one. The other first cells 211 refer to the first cells 211 not connected to the connector 6 and the first cells 211 not connected to the first electrode portion 7. Please refer to... Figure 5 The other first cells 211 refer to the first cell 211 between the two outermost first cells 211 on both sides. In some embodiments, please refer to... Figure 5 The first circuit board 3 includes a first conductive element 32, and the tabs of each other first cell 211 pass through a first opening 31 and are then laminated and soldered to the first conductive element 32.

[0071] In some embodiments, please refer to Figure 5 The second circuit board 4 has multiple second openings 41. The tabs of the other second battery cells 221 pass through the multiple second openings 41 and are then soldered to the second circuit board 4. The other second battery cells 221 refer to those not connected to the connector 6 and those not connected to the second electrode portion 8. Please refer to... Figure 5 The other second cells 221 refer to the second cell 221 between the two outermost second cells 221 on both sides. In some embodiments, please refer to... Figure 5 The second circuit board 4 includes a second conductive element 42, and the tabs of each other second battery cell 221 pass through a first opening 31 and are then laminated and soldered to the second conductive element 42.

[0072] This utility model provides an embodiment of an energy storage device, which includes the battery pack 100 described above. For the specific structure and function of the battery pack 100, please refer to the above embodiment, which will not be repeated here.

[0073] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A battery pack, characterized in that, include: The shell has a receiving space; A battery cell assembly is disposed in the receiving space, the battery cell assembly including a first battery cell assembly and a second battery cell assembly, the first battery cell assembly and the second battery cell assembly being arranged along a first direction; The first circuit board is connected to the first battery cell assembly; A second circuit board is connected to the second cell assembly, and the first circuit board and the second circuit board are located on the same side of the cell assembly; A first busbar is disposed on the first circuit board. The first busbar includes a first fixing part and a first soldering part, and the first fixing part protrudes from the first soldering part. The second busbar is disposed on the second circuit board; A connector is fixed to the first fixing part by a first fastener, and the connector connects the first busbar and the second busbar.

2. The battery pack according to claim 1, characterized in that, The first battery cell assembly includes a plurality of first battery cells, at least one of the tabs of the first battery cell is laminated and welded to the first welding portion, and both the tabs of the first battery cell and the first welding portion are located below the connector.

3. The battery pack according to claim 1, characterized in that, The second busbar includes a second fixing part and a second welding part, wherein the second fixing part protrudes from the second welding part; The connector is fixed to the second fixing part by a second fastener.

4. The battery pack according to claim 3, characterized in that, The second battery cell assembly includes a plurality of second battery cells, at least one of the tabs of the second battery cell being laminated and welded to the second welding portion, wherein both the tabs of the second battery cell and the second welding portion are located below the connector.

5. The battery pack according to claim 4, characterized in that, A plurality of first battery cells are arranged along the first direction; a plurality of second battery cells are arranged along the first direction; The battery pack includes a first electrode portion and a second electrode portion, the first electrode portion and the second electrode portion having opposite polarities. The first electrode portion is connected to the first cell among the plurality of first cells that is farthest from the connector, and the second electrode portion is connected to the second cell among the plurality of second cells that is farthest from the connector.

6. The battery pack according to claim 5, characterized in that, The battery pack includes a third busbar disposed on the first circuit board. The third busbar includes a third fixing part and a third welding part, and the third fixing part protrudes from the third welding part. The first electrode portion is fixed to the third fixing portion by a third fastener. The tab of the first battery cell, which is furthest from the connector, is laminated and welded to the third welding portion. The tab of the first battery cell and the first electrode portion do not overlap.

7. The battery pack according to claim 6, characterized in that, The battery pack includes a fourth busbar disposed on the second circuit board. The fourth busbar includes a fourth fixing part and a fourth welding part, the fourth fixing part protruding from the fourth welding part. The second electrode portion is fixed to the fourth fixing portion by a third fastener. The tab of the second battery cell, which is furthest from the connector, is laminated and welded to the fourth welding portion. Both the tab of the second battery cell and the fourth welding portion are located below the second electrode portion.

8. The battery pack according to claim 5, characterized in that, The first circuit board has a first opening, and the tabs of the other first cells pass through the first opening and are soldered to the first circuit board.

9. The battery pack according to claim 5, characterized in that, The second circuit board has a second opening, and the tabs of the other second cells pass through the second opening and are soldered to the second circuit board.

10. An energy storage device, characterized in that, Includes the battery pack as described in any one of claims 1-9.

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