Battery pack

Abstract

The utility model discloses a battery pack. The battery pack comprises a connecting sheet, a circuit board and a battery cell group, the circuit board is arranged on one side of the battery cell group, the battery cell group comprises a plurality of battery cells, the connecting sheet is arranged between two adjacent battery cells in the battery cell group, and the two adjacent battery cells are electrically connected through the connecting sheet; a first welding part and a second welding part are arranged on the circuit board, the connecting piece is electrically connected with the first welding part and the second welding part respectively, a voltage sampling point is arranged between the first welding part and the second welding part on the circuit board, and the distance difference between the voltage sampling point and the voltage sampling paths of the two adjacent battery cells is within a preset range. Therefore, the distance difference value of the two voltage sampling paths is set to be within the preset range, so that the voltage sampling paths of the two adjacent battery cells can be close or equal when the voltage sampling points are used for performing voltage sampling on the two adjacent battery cells, the two battery cells are ensured to be in a balanced state during voltage sampling, and the voltage sampling error is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of batteries, and particularly relates to a battery pack. BACKGROUND

[0002] In the process of connecting power batteries in series, the batteries are usually connected by end connectors. In the related art, for long strip series connection batteries, two battery cells are first connected in series by end connectors, and then the end connectors are electrically connected with a PCB. However, when the voltage of adjacent two battery cells is detected by a voltage detection point on the PCB, the distance of the voltage detection path from the voltage detection point to the two battery cells is inconsistent, resulting in a large voltage detection error. CONTENT OF THE UTILITY MODEL

[0003] The application aims to provide a battery pack, which can solve the problem that when the voltage of adjacent two battery cells is detected by a voltage detection point on a PCB, the distance of the voltage detection path from the voltage detection point to the two battery cells is inconsistent, resulting in a large voltage detection error.

[0004] To solve the above technical problem, the application is implemented as follows:

[0005] In a first aspect, the application provides a battery pack, comprising a connecting sheet, a circuit board and a battery cell group.

[0006] The circuit board is arranged on one side of the battery cell group, the battery cell group comprises a plurality of battery cells, the connecting sheet is arranged between adjacent two battery cells in the battery cell group, and the adjacent two battery cells are electrically connected by the connecting sheet. The circuit board is provided with a first welding portion and a second welding portion, the connecting sheet is electrically connected with the first welding portion and the second welding portion respectively, the circuit board is provided with a voltage detection point between the first welding portion and the second welding portion, and the distance difference of the voltage detection path from the voltage detection point to the adjacent two battery cells is within a preset range.

[0007] Optionally, the connecting sheet comprises a connecting section, a first extending section and a second extending section, the connecting section has a first connecting portion and a second connecting portion, the first connecting portion is connected with one of the adjacent two battery cells, and the second connecting portion is connected with the other of the adjacent two battery cells; the first extending section extends from the first connecting portion towards the first welding portion and is electrically connected with the first welding portion to form a first voltage detection path, the second extending section extends from the second connecting portion towards the second welding portion and is electrically connected with the second welding portion to form a second voltage detection path; and the distance difference of the first voltage detection path and the second voltage detection path is within a preset range.

[0008] Optionally, the two adjacent battery cells include a first battery cell and a second battery cell, the first battery cell and the second battery cell are arranged side by side, and the arrangement direction of the first connecting part and the second connecting part is consistent with the arrangement direction of the first battery cell and the second battery cell.

[0009] Optionally, one end of the first extension section away from the first connecting part is bent to form a first bent part, one end of the second extension section away from the second connecting part is bent to form a second bent part, the first bent part is electrically connected with the first welding part, and the second bent part is electrically connected with the second welding part.

[0010] Optionally, the bending direction of the first bent part is consistent with the bending direction of the second bent part.

[0011] Optionally, the two adjacent battery cells include a third battery cell and a fourth battery cell, the third battery cell and the fourth battery cell are butt-jointed, the first connecting part and the second connecting part are arranged in a folded manner and clamped between the third battery cell and the fourth battery cell.

[0012] Optionally, the circuit board is provided with a avoiding opening, one end of the first extension section away from the first connecting part penetrates through the avoiding opening and is bent to form a third bent part, one end of the second extension section away from the second connecting part is bent to form a fourth bent part, the third bent part is electrically connected with the first welding part, and the fourth bent part is electrically connected with the second welding part.

[0013] Optionally, the bending direction of the third bent part is opposite to the bending direction of the fourth bent part.

[0014] Optionally, the connecting section further includes a transition part arranged between the first connecting part and the second connecting part, and the transition part is provided with a notch.

[0015] Optionally, the connecting section further includes a transition part arranged between the first connecting part and the second connecting part, and the transition part is provided with a notch.

[0016] Optionally, the circuit board includes a circuit board body and a connecting piece, the circuit board body is arranged on one side of the battery cell group, the first welding part and the second welding part are arranged on the circuit board body, one end of the connecting piece is electrically connected with the first welding part, the other end of the connecting piece is electrically connected with the second welding part, and the pressure collection point is arranged on the connecting piece.

[0017] In the embodiments of the present application, a battery includes a connecting piece, a circuit board and a cell group; the circuit board is arranged on one side of the cell group; the cell group includes a plurality of cells, the connecting piece is arranged between two adjacent cells in the cell group, and the two adjacent cells are electrically connected through the connecting piece; the circuit board is provided with a first welding portion and a second welding portion, the connecting piece is electrically connected with the first welding portion and the second welding portion respectively, the circuit board is provided with a pressure sampling point between the first welding portion and the second welding portion, and the distance difference of the pressure sampling paths from the pressure sampling point to the two adjacent cells is within a preset range. In this way, one pressure sampling path is formed from the pressure sampling point to one of the cells through the first welding portion and the connecting piece, and another pressure sampling path is formed from the pressure sampling point to the other cell through the second welding portion and the connecting piece, and by setting the distance difference of the two pressure sampling paths within the preset range, the pressure sampling paths of the two adjacent cells can be similar or equal when the two adjacent cells are pressure sampled by the pressure sampling point, so as to ensure that the two cells are in a balanced state when pressure sampling, thereby reducing the pressure sampling error.

[0018] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the appended drawings, wherein:

[0020] Figure 1 is a schematic diagram of a cell string according to an embodiment of the present application;

[0021] Figure 2 is an exploded view of a battery pack according to an embodiment of the present application;

[0022] Figure 3 is a schematic diagram of a battery pack according to an embodiment of the present application;

[0023] Figure 4 is a schematic diagram of a circuit board of a battery pack according to an embodiment of the present application

[0024] Figure 5 is a schematic diagram of an unfolded state of a connecting piece according to an embodiment of the present application;

[0025] Figure 6 is a schematic diagram of a bent state of a connecting piece according to an embodiment of the present application;

[0026] Figure 7 is a schematic diagram of an unfolded state of another connecting piece according to an embodiment of the present application;

[0027] Figure 8is another schematic view of a bending state of a connecting piece according to an embodiment of the present application.

[0028] Reference signs:

[0029] 1 - battery pack; 2 - connecting piece; 3 - circuit board; 4 - battery cell group; 5 - battery cell; 6 - connecting section; 7 - first extension section; 8 - second extension section; 9 - first connecting part; 10 - second connecting part; 11 - first battery cell; 12 - second battery cell; 13 - third battery cell; 14 - fourth battery cell; 15 - first bending part; 16 - second bending part; 17 - avoiding opening; 18 - third bending part; 19 - fourth bending part; 20 - isolation piece; 21 - transition part; 22 - notch; 23 - circuit board body; 24 - connecting piece; 25 - first welding part; 26 - second welding part; 27 - end connecting piece; 28 - adhesive medium; 29 - insulation piece; 30 - shell; 31 - pressure collection point; 32 - power supply line; 33 - total positive electrode; 34 - total negative electrode. DETAILED DESCRIPTION

[0030] Embodiments of the present application will be described in detail below with reference to drawings, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to drawings are exemplary only, and are intended to explain the present application, and should not be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0031] The terms "first", "second" in the description and claims of the present application can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / ", generally means that the front and rear associated objects are in an "or" relationship.

[0032] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0034] The battery pack provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0035] like Figures 1 to 4 As shown, a battery pack 1 according to some embodiments of this application includes: a connecting piece 2, a circuit board 3, and a battery cell assembly 4;

[0036] Circuit board 3 is located on one side of battery cell assembly 4, which includes several battery cells 5. Connecting piece 2 is located between two adjacent battery cells 5 in battery cell assembly 4, and the two adjacent battery cells 5 are electrically connected through connecting piece 2. Circuit board 3 is provided with a first welding part 25 and a second welding part 26. Connecting piece 2 is electrically connected to the first welding part 25 and the second welding part 26 respectively. Circuit board 3 is provided with a pressure sampling point between the first welding part 25 and the second welding part 26. The distance difference between the pressure sampling point and the pressure sampling path of the two adjacent battery cells 5 is within a preset range.

[0037] In this embodiment, the circuit board 3 is disposed on one side of the cell assembly 4, and the connecting piece 2 is disposed between two adjacent cells 5 in the cell assembly 4. The connecting piece 2 is electrically connected to the two adjacent cells 5 and to the first welding part 25 and the second welding part 26, respectively. The circuit board 3 is provided with a pressure sampling point between the first welding part 25 and the second welding part 26. The distance difference between the pressure sampling point 31 and the pressure sampling path of the two adjacent cells 5 is within a preset range. In this way, a pressure sampling path is formed from the pressure sampling point 31 through the first welding part 25 and the connecting piece 2 to one of the cells 5, and another pressure sampling path is formed from the pressure sampling point 31 through the second welding part 26 and the connecting piece 2 to the other cell 5. By setting the distance difference between these two pressure sampling paths within a preset range, when pressure is applied to the two adjacent cells 5 using the pressure sampling point 31, the pressure sampling paths of the two adjacent cells 5 can be made similar or equal, thereby ensuring that the two cells 5 are in a balanced state when pressure is applied, thus reducing the pressure sampling error.

[0038] Specifically, the first welding part 25 and the second welding part 26 are located on the circuit board 3 at positions corresponding to the connection points of two adjacent battery cells 5. The battery cell assembly 4 is composed of multiple battery cells 5. Figure 1As shown, the battery cell assembly 4 includes four battery cells 5, which are connected end-to-end by connecting pieces 2. The battery cell assembly 4 has a length direction and a width direction, where the length direction is the axial direction of the battery cells 5. The circuit board 3 also has a length direction and a width direction, with the length direction of the battery cell assembly 4 consistent with the length direction of the circuit board 3. Of course, the number of battery cells 5 included in the battery cell assembly 4 is not limited and can be set according to actual needs.

[0039] It should be noted that the preset range can be flexibly set according to the actual situation, as long as the distance between the sampling paths of two adjacent cells is close or equal. This application embodiment does not limit this.

[0040] In some embodiments, the battery cell 5 may be a cylindrical battery cell 5 or a square battery cell 5, and the embodiments of this application are not limited herein.

[0041] It should be noted that two adjacent battery cells 5 are electrically connected by a connecting piece 2, which can be done by welding or by connecting the connecting piece 2 through a medium such as conductive adhesive. This embodiment of the application does not impose any restrictions on this.

[0042] In some embodiments, the battery pack 1 further includes an adhesive medium 28, through which the circuit board 3 and the cell assembly 4 are connected. The adhesive medium 28 may be double-sided tape, glue, or other adhesive mediums 28, and this embodiment of the application does not impose any limitations.

[0043] In some embodiments, the battery pack 1 further includes a protection circuit module (PCM) consisting of a circuit board 3, a power line 32, a management chip (not shown), a MOSFET (not shown), a resistor (not shown), and a capacitor (not shown). The PCM is used to manage the current and voltage of the battery pack 1. The power line 32 is electrically connected to the circuit board 3 and is used to output the current or voltage of the battery pack 1.

[0044] In some other embodiments, such as Figures 2-3 As shown, the battery pack 1 also includes a housing 30, in which a receiving cavity is provided, and the PCM, the cell assembly 4 and the connecting piece 2 are all located in the receiving cavity.

[0045] Optionally, the connecting piece 2 comprises a connecting section 6, a first extending section 7 and a second extending section 8, the connecting section 6 has a first connecting part 9 and a second connecting part 10, the first connecting part 9 is connected with one of the two adjacent battery cells 5, and the second connecting part 10 is connected with the other of the two adjacent battery cells 5; the first extending section 7 extends from the first connecting part 9 to the first welding part 25 and is electrically connected with the first welding part 25 to form a first pressure sampling path; the second extending section 8 extends from the second connecting part 10 to the second welding part 26 and is electrically connected with the second welding part 26 to form a second pressure sampling path; the distance difference between the first pressure sampling path and the second pressure sampling path is within the preset range.

[0046] In the embodiments of the present application, the first connecting part 9 is connected with one of the two adjacent battery cells 5, and the second connecting part 10 is connected with the other of the two adjacent battery cells 5; the first extending section 7 extends from the first connecting part 9 to the first welding part 25 and is electrically connected with the first welding part 25 to form a first pressure sampling path; the second extending section 8 extends from the second connecting part 10 to the second welding part 26 and is electrically connected with the second welding part 26 to form a second pressure sampling path. In this way, by setting the distance difference between the first pressure sampling path and the second pressure sampling path within the preset range, when the two adjacent battery cells 5 are sampled by the pressure sampling points 31 on the circuit board 3, the distance of the pressure sampling paths of the pressure sampling points 31 to the two adjacent battery cells is similar or equal, ensuring that the sampling is in a balanced state, thereby reducing the sampling error.

[0047] Specifically, the first extending section 7 and the second extending section 8 have the same or similar structure, and the first connecting part 9 and the second connecting part 10 have the same or similar structure. In this way, the distance of the first pressure sampling path and the second pressure sampling path can be similar or equal, ensuring that the sampling is in a balanced state, thereby reducing the sampling error.

[0048] In some embodiments, the connecting section 6 is dumbbell-shaped with large ends and a small middle. The two ends of the connecting section 6 are circular arc-shaped, that is, the edges of the first connecting part 9 and the second connecting part 10 are circular arc-shaped, so that the connecting section 6 is adapted to the battery cell 5. A waist-shaped welding hole is arranged at the middle position of the first connecting part 9 and the second connecting part 10, and the first connecting part 9 and the second connecting part 10 are respectively welded on the battery cell 5 through the waist-shaped welding hole.

[0049] In addition, the first extending section 7 and the first welding part 25, and the second extending section 8 and the second welding part 26 can be welded or connected through a conductive medium such as conductive glue.

[0050] Optionally, as shown in FIG. 6, the connecting piece 2 comprises a connecting section 6, a first extending section 7 and a second extending section 8, the connecting section 6 has a first connecting part 9 and a second connecting part 10, the first connecting part 9 is connected with one of the two adjacent battery cells 5, and the second connecting part 10 is connected with the other of the two adjacent battery cells 5; the first extending section 7 extends from the first connecting part 9 to the first welding part 25 and is electrically connected with the first welding part 25 to form a first pressure sampling path; the second extending section 8 extends from the second connecting part 10 to the second welding part 26 and is electrically connected with the second welding part 26 to form a second pressure sampling path; the distance difference between the first pressure sampling path and the second pressure sampling path is within the preset range. Figure 2As shown, the two adjacent battery cells 5 include a first battery cell 11 and a second battery cell 12, the first battery cell 11 and the second battery cell 12 are arranged side by side, and the arrangement direction of the first connecting portion 9 and the second connecting portion 10 is consistent with the arrangement direction of the first battery cell 11 and the second battery cell 12.

[0051] In the embodiment of the present application, by arranging the first connecting portion 9 and the second connecting portion 10 of the connecting sheet 2 in the same direction as the first battery cell 11 and the second battery cell 12, in the case of arranging the first battery cell 11 and the second battery cell 12 side by side, the first connecting portion 9 of the connecting sheet 2 is connected to the first battery cell 11, and the second connecting portion 10 is connected to the second battery cell 12.

[0052] Optionally, as shown, Figures 5-6 The end of the first extension section 7 away from the first connecting portion 9 is bent to form a first bent portion 15, and the end of the second extension section 8 away from the second connecting portion 10 is bent to form a second bent portion 16, the first bent portion 15 is electrically connected to the first welding portion 25, and the second bent portion 16 is electrically connected to the second welding portion 26.

[0053] In the embodiment of the present application, by bending the end of the first extension section 7 away from the first connecting portion 9 to form a first bent portion 15, and bending the end of the second extension section 8 away from the second connecting portion 10 to form a second bent portion 16, the first bent portion 15 is electrically connected to the first welding portion 25, and the second bent portion 16 is electrically connected to the second welding portion 26. In this way, when the pressure sampling point 31 is arranged on the circuit board 3, the distance of the pressure sampling path of the pressure sampling point 31 from the first bent portion 15 and the first connecting portion 9 to the first battery cell 11, and the distance of the pressure sampling path of the pressure sampling point 31 from the second bent portion 16 and the second connecting portion 10 to the second battery cell 12 are similar or equal, so that when the pressure is sampled between the first battery cell 11 and the second battery cell 12, the pressure is in a balanced state, thereby reducing the pressure sampling error.

[0054] Specifically, the first extension section 7 and the second extension section 8 are arranged on the same side of the connecting section 6, that is, the first extension section 7 and the second extension section 8 are parallel to each other, and the extension directions of the first extension section 7 and the second extension section 8 are perpendicular to the extension direction of the connecting section 6.

[0055] Optionally, the bending direction of the first bent portion 15 is consistent with the bending direction of the second bent portion 16.

[0056] In the embodiment of the present application, by arranging the bending direction of the first bent portion 15 and the bending direction of the second bent portion 16 to be consistent, in the case of arranging the first battery cell 11 and the second battery cell 12 side by side and arranging the circuit board 3 above the first battery cell 11 and the second battery cell 12, the connecting sheet 2 is connected to the circuit board 3 through the first bent portion 15 and the second bent portion 16 arranged in the same direction.

[0057] Optionally, as Figure 1 , as Figure 8 indicated, the two adjacent battery cells 5 include a third battery cell 13 and a fourth battery cell 14, the third battery cell 13 and the fourth battery cell 14 are butt-jointed, the first connecting part 9 and the second connecting part 10 are folded and arranged, and are clamped between the third battery cell 13 and the fourth battery cell 14.

[0058] In the embodiment of the present application, by folding and arranging the first connecting part 9 and the second connecting part 10 and clamping them between the third battery cell 13 and the fourth battery cell 14, in the case of butt-jointing the third battery cell 13 and the fourth battery cell 14, the first connecting part 9 is connected to the third battery cell 13, and the second connecting part 10 is connected to the fourth battery cell 14.

[0059] Specifically, the third battery cell 13 has a positive electrode and a negative electrode, the fourth battery cell 14 has a positive electrode and a negative electrode, and the butt-jointing of the third battery cell 13 and the fourth battery cell 14 means that the positive electrode of the third battery cell 13 is directly opposite the negative electrode of the fourth battery cell 14, or the negative electrode of the third battery cell 13 is directly opposite the positive electrode of the fourth battery cell 14.

[0060] It should be noted that the second battery cell 12 and the third battery cell 13 can be the same battery cell 5 or different battery cells 5, and the embodiment of the present application does not limit this. Exemplarily, as Figure 1 and Figure 2 indicated, the second battery cell 12 and the third battery cell 13 are the same battery cell 5.

[0061] Optionally, as Figure 4 , Figure 8 indicated, the circuit board 3 is provided with a avoiding port 17; one end of the first extending section 7 away from the first connecting part 9 passes through the avoiding port 17 and is bent to form a third bending part 18, the second extending section 8 is bent at one end away from the second connecting part 10 to form a fourth bending part 19, the third bending part 18 is electrically connected to the first welding part 25, and the fourth bending part 19 is electrically connected to the second welding part 26.

[0062] In the embodiment of the present application, by setting the avoiding opening 17 in the circuit board 3, the first extending section 7 passes through the avoiding opening 17 and is bent to form the third bending part 18 at one end away from the first connecting part 9, the second extending section 8 is bent to form the fourth bending part 19 at one end away from the second connecting part 10, the third bending part 18 is electrically connected with the first welding part 25, and the fourth bending part 19 is electrically connected with the second welding part 26. In this way, when the pressure sampling point 31 is set on the circuit board 3 to sample pressure, the distance of the pressure sampling path of the pressure sampling point 31 from the third bending part 18 and the first connecting part 9 to the third battery cell 13, and the distance of the pressure sampling path of the pressure sampling point 31 from the fourth bending part 19 and the second connecting part 10 to the fourth battery cell 14 are similar or equal, so that when the pressure is sampled between the third battery cell 13 and the fourth battery cell 14, the pressure sampling is in a balanced state, thereby reducing the pressure sampling error.

[0063] Specifically, as shown in Figure 7 the connecting sheet 2 is in a flattened state, the first extending section 7 and the second extending section 8 are respectively arranged at two ends of the connecting section 6, and when the connecting sheet is used, the first extending section 7 and the second extending section 8 are respectively bent to form the third bending part 18 and the fourth bending part 19. In the flattened state, the first extending section 7, the second extending section 8 and the connecting section 6 are coaxially arranged, that is, the axis of the first extending section 7, the axis of the second extending section 8 and the axis of the connecting section 6 coincide.

[0064] Optionally, the bending direction of the third bending part 18 and the bending direction of the fourth bending part 19 are opposite to each other.

[0065] In the embodiment of the present application, by setting the bending direction of the third bending part 18 and the bending direction of the fourth bending part 19 opposite to each other, in the case that the third battery cell 13 and the fourth battery cell 14 are butt-jointed and the circuit board 3 is arranged above the third battery cell 13 and the fourth battery cell 14, the connecting sheet 2 is connected with the circuit board 3 through the third bending part 18 and the fourth bending part 19 arranged opposite to each other.

[0066] Optionally, as shown in Figure 2 the connecting sheet 2 is in a flattened state, the first extending section 7 and the second extending section 8 are respectively arranged at two ends of the connecting section 6, and when the connecting sheet is used, the first extending section 7 and the second extending section 8 are respectively bent to form the third bending part 18 and the fourth bending part 19. In the flattened state, the first extending section 7, the second extending section 8 and the connecting section 6 are coaxially arranged, that is, the axis of the first extending section 7, the axis of the second extending section 8 and the axis of the connecting section 6 coincide.

[0067] In the embodiment of the present application, by setting the isolation sheet 20 between the first connecting part 9 and the second connecting part 10, the first connecting part 9 and the second connecting part 10 are isolated, so as to prevent the occurrence of electric arc due to the direct contact of the first connecting part 9 and the second connecting part 10, thereby affecting the performance of the battery.

[0068] Specifically, the shape of the isolation sheet 20 can be set according to the shape of the first connecting part 9 and the second connecting part 10, so as to match the isolation sheet 20 with the first connecting part 9 and the second connecting part 10.

[0069] In some embodiments, as shown in Figure 2 , two electric cells 5 connected end to end form one electric cell group, and another two electric cells 5 connected end to end form another electric cell group, and the two electric cell groups are insulated from each other by the insulating sheet 29 to prevent short circuit between the two electric cell groups and affect the safety of the battery pack 1.

[0070] Optionally, as shown in Figure 7 , the connecting section 6 further comprises a transition part 21 arranged between the first connecting part 9 and the second connecting part 10, and the transition part 21 is provided with a notch 22.

[0071] In the embodiments of the present application, for the first connecting sheet as shown in Figure 7 and Figure 8 , the connecting sheet needs to be bent from the transition part 21 when in use, and therefore, the notch 22 is arranged at the transition part 21 between the first connecting part 9 and the second connecting part 10, so that the first connecting part 9 and the second connecting part 10 are more convenient and simple to fold. For the second connecting sheet as shown in Figure 5 and Figure 6 , the connecting sheet does not need to be bent at the transition part 21 when in use, but in order to balance the pressure, the notch is also arranged at the transition part 21, so as to help reduce the pressure error.

[0072] In some embodiments, referring to Figure 7 and Figure 8 , Figure 7 , a structure schematic view of the first connecting sheet in an unfolded state is shown, Figure 8 , a structure schematic view of the first connecting sheet in a used state is shown. As shown in Figure 7 , in the unfolded state, one end of the transition part 21 is connected with the first connecting part 9, and the other end is connected with the second connecting part 10; the notch 22 is arranged in the transition part 21, so that when the transition part 21 needs to be bent to connect adjacent two electric cells 5, the transition part 21 is bent at the notch 22. Along the extension direction of the transition part 21, there are two opposite sides, and the notch 22 is arranged at the midpoint of the two sides. The notch 22 can avoid the problem that the first connecting part 9 and the second connecting part 10 are prone to be broken at the bending part due to stress concentration caused by direct bending.

[0073] In other embodiments, referring to Figure 5 and Figure 6 , Figure 5A structural schematic diagram showing the second connecting piece in an unfolded state is shown, Figure 6 A structural schematic diagram showing the second connecting piece in a use state is shown. As Figure 6 shown, in the use state, the connecting piece does not need to be bent at the transition portion 21 when connected with the battery cell 5. In order to make the structure of the transition portion 21 of the second connecting piece compatible with the structure of the transition portion 21 of the first connecting piece, a notch 22 is also provided at the transition portion 21 of the second connecting piece, and the size, position and setting shape of the notch 22 at the transition portion 21 of the two connecting pieces are the same, avoiding the problem of large pressure sampling error caused by the two different structures of the notch 22 when sampling pressure. Figure 5 and Figure 7 , the size, position and setting shape of the notch 22 at the transition portion 21 of the two connecting pieces are the same, avoiding the problem of large pressure sampling error caused by the two different structures of the notch 22 when sampling pressure.

[0074] It should be noted that the notch 22 can be a circular arc shape, or a triangular shape, etc., which is not limited in the embodiments of the present application.

[0075] Optionally, as Figure 4 shown, the circuit board 3 includes a circuit board body 23 and a connecting piece 24, the circuit board body 23 is arranged on one side of the battery cell group 4, the circuit board body 23 is provided with a first welding portion 25 and a second welding portion 26, one end of the connecting piece 24 is electrically connected with the first welding portion 25, the other end of the connecting piece 24 is electrically connected with the second welding portion 26, and the pressure sampling point 31 is arranged on the connecting piece 24.

[0076] In the embodiments of the present application, by arranging the first welding portion 25 and the second welding portion 26 on the circuit board body 23, one end of the connecting piece 24 is electrically connected with the first welding portion 25, and the other end of the connecting piece 24 is electrically connected with the second welding portion 26. In this way, when the pressure sampling point 31 is arranged on the connecting piece 24, the pressure sampling point 31 passes through the first welding portion 25, the first extension section 7 and the first connecting portion 9 to reach one of the two adjacent battery cells 5, and the pressure sampling point 31 passes through the second welding portion 26, the second extension section 8 and the second connecting portion 10 to reach the other of the two adjacent battery cells 5, the distances of the two pressure sampling paths are similar or equal, ensuring that the pressure sampling is in a balanced state, thereby reducing the pressure sampling error.

[0077] Specifically, the connecting piece 24 can be a copper foil prearranged on the circuit board 3, one end of the copper foil is connected with the first welding portion 25, and the other end is connected with the second welding portion 26, which can improve the integration of the circuit board, facilitate modular design, and avoid various safety hazards caused by flying wires.

[0078] In some embodiments, the battery pack further includes an end connecting piece 27, the battery cell group has a total positive electrode 33 and a total negative electrode 34, the total positive electrode 33 is connected with the circuit board 3 through the end connecting piece 27, and the total negative electrode 34 is connected with the circuit board 3 through the end connecting piece 27.

[0079] In the description of the application, reference has been made to descriptive terms such as "one embodiment", "some embodiments", "an embodiment", "example", "specific example" or "some examples" etc. It is emphasized that each of these terms refers to a specific feature, structure, material or characteristic described in connection with a particular embodiment or example. The descriptive terms are not necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0080] Although embodiments of this application have been shown and described, it is to be understood that various modifications, substitutions, combinations, and variations can be made therein without departing from the spirit and scope of the application. The application is not to be limited by the embodiments shown and described, but only by the claims and their equivalents.

Claims

1. A battery pack (1) characterized in that, The application relates to a battery cell group and a connecting sheet thereof. The connecting sheet (2) is arranged between two adjacent battery cells (5) in the battery cell group (4) and electrically connects the two adjacent battery cells (5). The connecting sheet (2) comprises a connecting section (6), a first extending section (7) and a second extending section (8). The connecting section (6) has a first connecting part (9) and a second connecting part (10), the first connecting part (9) is connected with one of the two adjacent battery cells (5), and the second connecting part (10) is connected with the other of the two adjacent battery cells (5); the first extending section (7) extends from the first connecting part (9) towards the first welding part (25) and is electrically connected with the first welding part (25) to form a first pressure sampling path; the second extending section (8) extends from the second connecting part (10) towards the second welding part (26) and is electrically connected with the second welding part (26) to form a second pressure sampling path; and the distance difference between the first pressure sampling path and the second pressure sampling path is within a preset range.

2. The battery pack (1) according to claim 1, characterized in that The first connecting part (9) and the second connecting part (10) are arranged in the same direction as the first battery cell (11) and the second battery cell (12). The first extending section (7) is bent at one end away from the first connecting part (9) to form a first bent part (15), the second extending section (8) is bent at one end away from the second connecting part (10) to form a second bent part (16), the first bent part (15) is electrically connected with the first welding part (25), and the second bent part (16) is electrically connected with the second welding part (26).

3. The battery pack (1) according to claim 2, characterized in that The bending direction of the first bent part (15) is consistent with the bending direction of the second bent part (16).

4. The battery pack (1) according to claim 3, characterized in that The first connecting part (9) and the second connecting part (10) are arranged in a folded mode and clamped between the third battery cell (13) and the fourth battery cell (14).

5. The battery pack (1) according to claim 4, characterized in that ​ 6. The battery pack (1) according to claim 2, characterized in that ​ 7. The battery pack (1) according to claim 5, characterized in that The circuit board (3) is provided with an avoiding opening (17); one end of the first extension section (7) away from the first connecting part (9) passes through the avoiding opening (17) and is bent to form a third bending part (18), the second extension section (8) is bent to form a fourth bending part (19) at one end away from the second connecting part (10), the third bending part (18) is electrically connected with the first welding part (25), and the fourth bending part (19) is electrically connected with the second welding part (26).

8. The battery pack (1) according to claim 7, characterized in that The bending direction of the third bending part (18) and the bending direction of the fourth bending part (19) are opposite to each other.

9. The battery pack (1) according to claim 6, characterized in that Further comprising an isolation sheet (20); the isolation sheet (20) is arranged between the first connecting part (9) and the second connecting part (10).

10. The battery pack (1) according to claim 2, characterized in that, The connecting section (6) further comprises a transition part (21) arranged between the first connecting part (9) and the second connecting part (10), and the transition part (21) is provided with a notch (22).

11. The battery pack (1) according to claim 1, characterized in that, The circuit board (3) comprises a circuit board body (23) and a connecting piece (24), the circuit board body (23) is arranged on one side of the battery cell group (4), the first welding part (25) and the second welding part (26) are arranged on the circuit board body (23), one end of the connecting piece (24) is electrically connected with the first welding part (25), the other end of the connecting piece (24) is electrically connected with the second welding part (26), and the pressure collecting point (31) is arranged on the connecting piece (24).

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