Connecting sheet, battery pack and electric apparatus

Abstract

A connecting sheet (100), a battery pack (200), and an electric apparatus. The connecting sheet (100) comprises a body (10), and the body (10) is provided with: an electrode connecting portion (11), which is configured to connect an electrode terminal; and a fusing portion (12), which is arranged on one side of the electrode connecting portion (11), wherein the minimum distance d0 between the fusing portion (12) and the outer peripheral edge of the electrode connecting portion (11) is 2 mm to 20 mm, and the current-passing area of the fusing portion (12) is less than the current-passing area of the remaining portion on the body (10).

Description

Connectors, battery packs, and electrical equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on the Chinese patent application with application number 202322687725.X and application date September 28, 2023, and claims the priority of the above-mentioned Chinese patent application. The entire content of the above-mentioned Chinese patent application is hereby introduced into this application as a reference. Technical Field

[0003] The present application relates to the field of battery technology, and more specifically, to a connecting piece, a battery pack having the connecting piece, and an electrical device. Background Art

[0004] Currently, when using cylindrical cells as power batteries for new energy vehicles, it is generally necessary to increase the overall pack capacity by connecting the cells in series and parallel. When multiple cells are connected in series and parallel, if one cell experiences thermal runaway, the remaining cells will experience external short-circuit discharge. Sustained short-circuit discharge generates a large amount of heat, leading to thermal diffusion and posing a safety hazard.

[0005] Summary of the Invention

[0006] The present application aims to solve one of the technical problems in the related art at least to a certain extent.

[0007] To this end, one purpose of the present application is to propose a new technical solution for connecting pieces, which can at least solve the problem in the prior art that the melting speed of connecting pieces cannot meet the requirements.

[0008] Another object of the present application is to provide a battery pack.

[0009] Another object of the present application is to provide an electrical device.

[0010] According to the first aspect of the present application, a connecting piece is provided, comprising a main body, on which is provided: an electrode connecting portion, which is used to connect an electrode terminal; and a fuse portion, which is provided on one side of the electrode connecting portion, and the minimum distance d0 between the fuse portion and the outer peripheral edge of the electrode connecting portion is 2 mm-20 mm, wherein the flow area of ​​the fuse portion is smaller than the flow area of ​​the remaining parts of the main body.

[0011] According to the connecting piece of the embodiment of the present application, by arranging the fuse part near the electrode connecting part, when in use, if the battery cell has thermal runaway, the runaway heat will accelerate the temperature rise of the connecting piece and accelerate the melting speed of the fuse part. At the same time, the local melting defect has little effect on the overcurrent between the electrode terminals and the strength of the connecting piece, and does not affect the normal use of the connecting piece.

[0012] According to a second aspect of the present application, a battery pack is provided, comprising a plurality of battery cells, each of which is provided with an electrode terminal; according to the connecting piece described in the above embodiment, the electrode connecting portion is connected to the electrode terminals.

[0013] According to the battery pack of the present application, when in use, if thermal runaway occurs in the battery cell, the runaway heat will accelerate the temperature rise of the connecting piece and accelerate the melting speed of the fuse part. At the same time, the local melting defect has little effect on the overcurrent between the electrode terminals and the strength of the connecting piece, and does not affect the normal use of the connecting piece.

[0014] According to a third aspect of the present application, an electrical device is provided, comprising the battery pack described in the above embodiment.

[0015] According to the electrical equipment of the present application, when in use, if thermal runaway occurs in the battery cell, the runaway heat will accelerate the temperature rise of the connecting piece and accelerate the melting speed of the fuse part. At the same time, the local melting defect has little effect on the overcurrent between the electrode terminals and the strength of the connecting piece, and does not affect the normal use of the connecting piece.

[0016] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG1 is a schematic structural diagram of a connecting piece according to an embodiment of the present application;

[0018] FIG2 is a schematic diagram of a partial structure of a connecting piece according to another embodiment of the present application;

[0019] FIG3 is a schematic diagram of a partial structure of a connecting piece according to another embodiment of the present application;

[0020] FIG4 is a schematic diagram of a partial structure of a connecting piece according to another embodiment of the present application;

[0021] FIG5 is a schematic diagram of a partial structure of a connecting piece according to another embodiment of the present application;

[0022] FIG6 is a diagram showing a connection sheet in use according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0024] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present disclosure, its application, or uses.

[0025] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0026] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0027] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0028] The following first describes in detail the connecting sheet 100 according to an embodiment of the present application with reference to the accompanying drawings.

[0029] As shown in FIG. 1 to FIG. 6 , the connecting piece 100 according to the embodiment of the present application includes a body 10 , on which are provided: an electrode connecting portion 11 and a fuse portion 12 .

[0030] Specifically, the electrode connecting part 11 is used to connect the electrode terminal, and the fuse part 12 is arranged on one side of the electrode connecting part 11. The minimum distance d0 between the fuse part 12 and the outer periphery of the electrode connecting part 11 is 2mm-20mm, wherein the flow area of ​​the fuse part 12 is smaller than the flow area of ​​the rest of the body 10.

[0031] In other words, the connecting piece 100 according to the embodiment of the present application is mainly composed of the main body 10, that is, the main body 10 constitutes the main part of the connecting piece 100, and the connecting piece 100 can be used to connect the electrode terminals of adjacent battery cells to realize the assembly of adjacent battery cells. The main body 10 is provided with an electrode connecting portion 11 and a fuse portion 12. The electrode connecting portion 11 serves to connect the electrode terminal, for example, it can be welded to the electrode terminal. The electrode connecting portion 11 can be a connecting hole provided on the main body 10, or it can be other structures that can be connected to the electrode terminal, which is not limited here. For example, when the electrode connecting portion 11 is a connecting hole provided on the main body 10, the outer periphery of the electrode connecting portion 11 can be the edge of the connecting hole or the outer periphery of the weld mark of the connecting hole and the electrode terminal; when the electrode connecting portion 11 is a preset point provided on the main body 10, the outer periphery of the electrode connecting portion 11 can be the outer periphery of the weld mark of the main body 10 and the electrode terminal.

[0032] The fuse 12 is located near the electrode connection portion 11, as shown in Figures 1 and 2, and the minimum distance d0 between the fuse 12 and the electrode connection portion 11 is controlled to be between 2mm and 20mm. The fuse 12, as a defective melting point, is arranged near the connection point between the connecting piece 100 and the battery cell. The flow area of ​​the fuse 12 is smaller than the flow area of ​​the rest of the body 10. That is, the width or thickness of the fuse 12 is the smallest width or thickness of the flow area of ​​the body 10. When the battery cell experiences thermal runaway, the body 10 is exposed to high temperatures, which will accelerate the melting of the area where the fuse 12 is located, thereby accelerating the rate at which the connecting piece 100 disconnects the electrical connection.

[0033] Furthermore, the localized fuse defect is located near the electrode connection portion 11. The proper placement of the fuse defect minimizes the crossover area between the cells and the strength of the connecting piece 100, thus maintaining the proper connection performance of the connecting piece 100. This effectively prevents the problem of the fuse defect being difficult to open due to low voltage and low short-circuit current when a short circuit occurs between the cells, thus reducing potential safety hazards.

[0034] Therefore, according to the connecting piece 100 of the embodiment of the present application, by arranging the fuse part 12 at a position close to the electrode connecting part 11, when in use, if thermal runaway occurs in the electrode terminal, the runaway heat will accelerate the temperature rise of the connecting piece and accelerate the melting speed of the fuse part 12. At the same time, the local melting defect has little effect on the overcurrent between the electrode terminals and the strength of the connecting piece 100, and does not affect the normal use of the connecting piece 100.

[0035] According to some embodiments of the present application, a thinning design is performed at a position close to the electrode connecting portion 11, that is, the thickness of a part of the main body 10 is made smaller at a suitable position. For example, a groove is provided on the main body 10 on one side in the thickness direction of the main body 10 by removing material, etc. The groove extends through the main body 10 along the width direction of the main body 10, and the distance between the groove and the other side of the main body 10 in the thickness direction is smaller than the thickness of the rest of the main body 10. The part with the smallest distance between the groove and the other side of the main body 10 in the thickness direction is formed as the fuse portion 12. This method is easy to implement, and of course the thickness can be thinned by other methods, which are not limited here.

[0036] According to some embodiments of the present application, the main body 10 is provided with at least one through-hole 13 extending through the main body 10 in the thickness direction thereof, and the portion with the shortest distance between the edge of the through-hole 13 and the edge of the main body 10 or the portion with the distance blocked between the edge of the adjacent through-hole 13 forms at least one sub-fuse portion, and the fuse portion 12 includes at least one sub-fuse portion.

[0037] In other words, according to the embodiment of the present application, the fuse part 12 on the connecting piece 100 can be composed of multiple sub-fuse parts, the specific number of which can be reasonably adjusted according to the number of electrode connecting parts 11 and the overcurrent requirements. One sub-fuse part in the fuse part 12 can be realized by setting a through-opening 13 on the main body 10. By setting the through-opening 13, the size of the connecting piece 100 can be reduced in the width direction, for example, to form the fuse part 12. The number of through-openings 13 can be one or more, so as to meet the use needs of different products.

[0038] In some specific embodiments of the present application, a through opening 13 is provided on the main body 10 at a position corresponding to the electrode connecting portion 11. The through opening 13 is formed as a groove recessed inward along one side edge of the main body 10, and a sub-fuse portion is formed between the edge of the through opening and the other side edge of the main body 10.

[0039] Specifically, as shown in Figure 3, in this embodiment, a groove recessed into the interior of the body 10 is formed on one edge of the body 10 near one electrode connection portion 11. This groove structure forms a through opening 13, and the portion between the edge of the through opening 13 and the other edge near the electrode connection portion 11 forms the fuse portion 12. Thus, the body 10 of this structure is simple to form and easy to manufacture while ensuring both a high fusing speed and a high fusing effect.

[0040] Optionally, according to some embodiments of the present application, two through-openings 13 are provided on the main body 10 at positions corresponding to the electrode connecting portion 11, and the two through-openings 13 are provided on two opposite side edges of the main body 10, and each through-opening 131 is formed as a groove recessed inward along the edge of the main body 10, and a sub-fuse portion is formed between the edges of the two through-openings.

[0041] As shown in Figure 4, in this embodiment, grooves recessed into the interior of the body 10 are provided on both sides of the body 10 near one electrode connection portion 11. These two grooves form openings 13, and the fuse portion 12 is formed between the opposing edges of the two openings 13. As a result, the body 10 with this structure can ensure that the forces on both sides of the fuse portion 12 are relatively uniform, effectively ensuring the strength of the body 10 while ensuring the melting speed and melting effect.

[0042] In other specific embodiments of the present application, a through opening 13 is provided on the main body 10 at a position corresponding to the electrode connecting portion 11. The through opening 13 is provided between the two opposite edges of the main body 10, and sub-fuse portions are formed between the edges of the through opening 13 and the two side edges of the main body 10.

[0043] Specifically, as shown in Figures 1 and 2, in this embodiment, a through-hole 13 can be provided at a position on the body 10 corresponding to an electrode connecting portion 11. The through-hole 13 can be formed as a through hole provided in the middle of the body 10. The area between the inner edge of the through-hole 13 close to the side edge of the body 10 and the side edge of the body 10 forms the fuse portion 12. The inner edge of the through-hole 13 close to the side edge of the body 10 can be a straight line, a curve, or other available linear structures. In other words, the shape of the through-hole 13 can be, for example, a trapezoidal structure as shown in Figure 2, or a circular arc structure as shown in Figure 1. As a result, the body 10 of this structure is not only easy to form, but also can ensure the overall strength of the body 10 while ensuring the melting speed and melting effect.

[0044] Optionally, according to some embodiments of the present application, a plurality of openings 13 are provided at positions on the main body 10 corresponding to the electrode connecting portion 11, and the plurality of openings 13 are spaced apart between the oppositely disposed edges of the main body 10. A first sub-fuse portion is formed between the edge of the main body 10 and the edge of the opening 13 close to the edge of the main body 10, and a second sub-fuse portion is formed between the edges of two adjacent openings.

[0045] As shown in FIG5 , in this embodiment, two openings 13 are provided between the edges of the body 10 at a position corresponding to an electrode connection portion 11. Each opening 13 is formed as a hole-shaped structure with a closed periphery. The area between the inner edge of each opening 13 and the edge of the side of the body 10 closest to it forms a first fuse section, and the area between the inner edges of two adjacent openings 13 also forms a second fuse section. That is, the body 10 shown in FIG5 is provided with three sub-fuse sections, which together constitute the fuse section 12. As a result, the body 10 with this structure can further ensure the strength of the body 10 while controlling the fusing speed and fusing effect.

[0046] In some specific embodiments of the present application, the electrode connecting portion 11 is formed in a circular shape, and the at least one through-opening 13 is formed as a fan-shaped through-hole concentric with the electrode connecting portion 11 .

[0047] Specifically, as shown in Figures 1, 2 or 5, the electrode connecting portion 11 on the main body 10 that is connected to the electrode terminal is a circular structure, and the through-opening 13 is formed as a hole-type structure arranged between the two side edges of the main body 10, and the shape of the through-opening 13 is adapted to the shape of the electrode connecting portion 11, that is, the through-opening 13 can be formed as a fan-shaped through-hole coaxial with the electrode connecting portion 11, and the inner edges on both sides of the through-opening 13 of this structure respectively form a fuse portion 12 between the two side edges of the main body 10.

[0048] Considering that the melting speed of the connecting piece 100 is determined by the position of the fuse part 12 and the melting point of the material of the connecting piece 100, the temperature at the position of the fuse part 12 is affected by the overcurrent heating and the transfer of heat from thermal runaway. The corresponding parameters have corresponding calculation formulas. For example, when the connecting piece 100 is assembled with the battery cell, after the battery cell thermal runaway, the short-circuit current can be calculated by the formula n×U 电芯 / R 失控电芯 Calculation shows that, where n is the number of battery cells, the resistance of the battery cell after thermal runaway is approximately 0.03Ω, and the short-circuit current is approximately I=100×(n-1)A.

[0049] The connecting piece 100 may be made of aluminum. The melting point of the fuse part 12 needs to reach 660° C. when it is melted. Therefore, the structure of the connecting piece 100 needs to be reasonably designed.

[0050] The thickness of the connecting piece 100 is h, and the flow area of ​​the fuse 12 is S = l × h, where l is the width of the fuse 12. The opening 13 is formed into a slit structure. The width d1 of the slit (as shown in FIG2 ) and the flow area S determine the local resistance R of the flow area, R = ρ 电阻率 ×d1÷S, so the short-circuit current in the slit generates heat Q 过流 =I 2 ×R.

[0051] The thermal runaway process generates heat for about 30 seconds. The heat generated by thermal runaway is transferred from the battery cell pole to the connecting piece 100. The heating power is inversely proportional to the distance of heat transfer and can be approximated as Q 热失控 =15 / d0W.

[0052] Therefore, Q 总 =I 2 ×R+15 / d0. Slit temperature rise rate dT / dt=(I 2 ×R+15 / d0) / Cp / m. Where Cp is the specific heat capacity of aluminum, m is the mass of the slit aluminum, and m=ρ 密度 ×l×d1×h. If the non-diffusion requirement is met, the requirement of melting within 30s must be met, that is, the temperature rise rate is greater than 21.2℃ / s. dT / dt=(I 2 ×R+15 / d0) / Cp / m>21.2.

[0053] Right now:

[0054] Among them, ρ resistivity is the resistivity of the fuse part 12, ρ density is the density of the fuse part 12, Cp is the specific heat capacity of the fuse part 12, S is the flow area of ​​the fuse part 12, d1 is the distance between the side of the opening 13 close to the electrode connecting part 11 and the side away from the electrode connecting part 11, and n is the number of battery cells arranged in parallel.

[0055] Taking into account the design strength requirements and process feasibility of the connecting piece 100, according to some embodiments of the present application, the distance d1 between the side of the through-hole 13 closest to the electrode connecting portion 11 and the side farther away from the electrode connecting portion 11 is 1 mm to 5 mm, preferably 1 mm to 3 mm. Optionally, the thickness h of the body 10 is 0.1 mm to 1.5 mm.

[0056] In other words, considering the fusing requirements and cost requirements of the connecting piece 100, the design rules for the connecting piece 100 are as follows: the distance d0 between the fusing portion 12 and the electrode connecting portion 11 should be between 2 mm and 20 mm, and the slit width d1 should be between 1 mm and 3 mm. As a result, the connecting piece 100 of this structure is easier to manufacture and more cost-effective while ensuring both fusing speed and effectiveness.

[0057] Optionally, according to some embodiments of the present application, there is one fuse part 12, and the relationship between the area S of the fuse part 12 and the thickness h of the body 10 is: 0.5 mm 2 ≤S=l*h≤10mm 2 , where l is the minimum width of the fuse portion 12.

[0058] As shown in FIG3 and FIG4, in this embodiment, there is only one fuse part 12, and the minimum width of the fuse part 12 is l. The area S of the fuse part 12 of this structure is the product of the width l of the fuse part 12 and the thickness of the connecting piece 100. The area S of the fuse part 12 is 1mm. 2 Up to 10mm 2 Thus, the fusing effect of the fusing portion 12 can be ensured.

[0059] In some other specific embodiments of the present application, there are multiple fuse parts 12, and the multiple fuse parts 12 are spaced apart. The relationship between the area S of the fuse part 12 and the thickness h of the body 10 is: 0.5mm 2 ≤S=L*h≤(n-1)×10mm2, where L is the sum of the minimum widths of the plurality of fuse parts 12, and n is the number of battery cells arranged in parallel.

[0060] As shown in Figures 1, 2 and 5, in this embodiment, there are at least two fuse parts 12, each of which has a minimum width. The sum of the minimum widths of the multiple fuse parts 12 is L. The area S of the fuse part 12 of this structure is the product of the sum L of the minimum total widths of the multiple fuse parts 12 and the thickness of the connecting piece 100. The area S of the fuse part 12 is greater than 1mm 2 , and less than (n-1)×10mm 2 Since the number of battery cells arranged in parallel will affect the short-circuit current, the overflow area S of the fuse 12 will also be adjusted according to the number of battery cells arranged in parallel.

[0061] In addition, for the steel or copper connecting piece 100, the design principle of the fuse part 12 is the same as that of the aluminum connecting piece 100. Considering the difference in material, for the steel connecting piece 100, the relationship between the area S of the fuse part 12 and the thickness h of the body 10 is: 2 ≤S=L*h≤(n-1)×3mm 2 , where L is the sum of the minimum widths of the multiple fuse parts 12, and n is the number of cells connected in parallel. For the copper connecting piece 100, the relationship between the area S of the fuse part 12 and the thickness h of the body 10 is: 0.5mm 2 ≤S=L*h≤(n-1)×5mm 2 , where L is the sum of the minimum widths of the plurality of fuse parts 12, and n is the number of battery cells arranged in parallel.

[0062] Optionally, the number of sub-fuses is 5 or less, meaning there can be 1-5 sub-fuses. The number of cells connected in parallel determines the magnitude of the short-circuit current after thermal runaway, so the overcurrent area also needs to be determined based on the number of cells connected in parallel. This ensures the fusing effect of the fuse 12 while also maintaining the overall strength of the electrode sheet 100.

[0063] According to one embodiment of the present application, the body 10 includes: a plurality of series connection sections 101 and parallel connection sections 102 .

[0064] Specifically, multiple series connection sections 101 are arranged spaced apart from each other, the parallel connection section 102 is connected to two adjacent series connection sections 101, the electrode connection part 11 is arranged at the connection between the parallel connection section 102 and the series connection section 101, and the fuse part 12 is arranged on the side of the electrode connection part 11 close to the parallel connection section 102.

[0065] That is, the connecting piece 100 can be composed of multiple series connection segments 101 and parallel connection segments 102, wherein the series connection segments 101 can be used to connect the electrode terminals of multiple battery cells arranged in series, and the parallel connection segments 102 are used to connect two adjacent series connection segments 101. In this way, the connecting piece 100 can be connected to multiple electrode terminals.

[0066] Optionally, there are two series connection sections 101 , and the two series connection sections 101 are arranged on the same side of the parallel connection section 102 .

[0067] In some other specific embodiments of the present application, the two series connection sections 101 are arranged in parallel, and the parallel connection section 102 is perpendicular to the series connection section 101 or is inclined relative to the series connection section 101 .

[0068] Specifically, as shown in Figure 6, two series connection segments 101 can be connected to a parallel connection segment 102 to form a U-shaped structure, with multiple battery cells 201 connected in parallel. The positive and negative poles of the battery cells 201 can be adjusted as needed. Two series connection segments 101 can be connected to a parallel connection segment 102 to form a C-shaped structure. Thus, the connecting piece 100 of this structure can meet the connection requirements of two parallel groups of battery cells 201.

[0069] According to some embodiments of the present application, there are two series connection sections 101, and the two series connection sections 101 are arranged on both sides of the parallel connection section 102. The two series connection sections 101 are connected to the same end of the parallel connection section 102, and the two series connection sections 101 are symmetrically arranged relative to the parallel connection section 102.

[0070] Optionally, there are multiple series connection sections 101 and multiple parallel connection sections 102 , and the multiple series connection sections 101 and the multiple parallel connection sections 102 are alternately arranged in sequence.

[0071] In other words, the connecting piece 100 of this structure can meet the connection requirements of multiple groups of parallel-connected battery cells 201 .

[0072] The battery pack 200 according to an embodiment of the present application includes: a plurality of battery cells 201 and a connecting sheet 100 according to the above embodiment. Each battery cell 201 is provided with an electrode terminal, and the electrode connecting portion 11 is connected to the electrode terminal. Optionally, the electrode terminal is a pole or shell of the battery cell 201.

[0073] The electrical device according to the embodiment of the present application includes the battery pack 200 according to the above embodiment, and the electrical device can be a vehicle, etc. Since the connecting piece 100 according to the above embodiment of the present application has the above technical effects, the battery pack 200 and the electrical device according to the embodiment of the present application also have corresponding technical effects, that is, the connecting piece 100 has a good fusing effect and high safety.

[0074] Although some specific embodiments of the present application have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A connecting sheet, wherein: It comprises a main body (10), on which is provided: An electrode connecting portion (11), wherein the electrode connecting portion (11) is used to connect an electrode terminal; A fuse part (12), the fuse part (12) being arranged on one side of the electrode connecting part (11), the minimum distance d0 between the fuse part (12) and the outer peripheral edge of the electrode connecting part (11) being 2 mm-20 mm, wherein the flow area of ​​the fuse part (12) is smaller than the flow area of ​​the rest of the body.

2. The connecting sheet according to claim 1, wherein: The body (10) is provided with at least one through-hole (13) penetrating along the thickness direction thereof, the portion of the edge of the through-hole (13) with the shortest distance from the edge of the body (10) or the portion of the edge of the through-hole (13) with the shortest distance from the adjacent edge of the through-hole (13) forming at least one sub-fuse portion, and the fuse portion (12) includes at least one of the sub-fuse portions.

3. The connecting sheet according to claim 2, wherein: A through opening (13) is provided at a position on the body (10) corresponding to the electrode connecting portion (11); the through opening (13) is formed as a groove recessed inwardly along one side edge of the body (10); and the sub-fuse portion is formed between the edge of the through opening (13) and the other side edge of the body (10).

4. The connecting sheet according to claim 2, wherein: Two through openings (13) are provided at positions on the body (10) corresponding to the electrode connecting portion (11); the two through openings (13) are provided on two oppositely disposed edges of the body (10); each through opening (13) is formed as a groove recessed inwardly along the edge of the body (10); and the sub-fuse portion is formed between the edges of the two through openings (13).

5. The connecting sheet according to claim 2, wherein: A through opening (13) is provided at a position on the body (10) corresponding to the electrode connecting portion (11); the through opening (13) is provided between two oppositely disposed edges of the body (10); and the sub-fuse portions are respectively formed between the edges of the through opening (13) and the two opposite edges of the body (10).

6. The connecting sheet according to claim 2, wherein: A plurality of through openings (13) are provided at positions on the body (10) corresponding to the electrode connecting portion (11); the plurality of through openings (13) are spaced apart between two oppositely disposed edges of the body (10); a first sub-fuse portion is formed between the edge of the body (10) and the edge of the through opening (13) close to the edge of the body (10); and a second sub-fuse portion is formed between the edges of two adjacent through openings (13).

7. The connecting sheet according to claim 2, wherein: The electrode connecting portion (11) is formed in a circular shape, and at least one of the through openings (13) is formed as a fan-shaped through hole concentric with the electrode connecting portion (11).

8. The connecting sheet according to claim 2, wherein: A distance d1 between a side of the through opening (13) close to the electrode connecting portion (11) and a side away from the electrode connecting portion (11) is 1 mm to 5 mm.

9. The connecting sheet according to claim 2, wherein: The number of the sub-fuse parts is less than or equal to 5.

10. The connecting sheet according to claim 1, wherein: The body (10) comprises: A plurality of serially connected segments (101), wherein the plurality of serially connected segments (101) are arranged spaced apart from each other; A parallel connection section (102), wherein the parallel connection section (102) and the two adjacent series connection sections (101) The electrode connection portion (11) is arranged at the connection between the parallel connection section (102) and the series connection section (101), and the fuse portion (12) is arranged on a side of the electrode connection portion (11) close to the parallel connection section (102).

11. The connecting sheet according to claim 10, wherein: There are two series connection sections (101), and the two series connection sections (101) are arranged on the same side of the parallel connection section (102).

12. The connecting sheet according to claim 11, wherein: The two series connection sections (101) are arranged in parallel, and the parallel connection section (102) is perpendicular to the series connection section (101) or is arranged obliquely relative to the series connection section (101).

13. The connecting piece according to any one of claims 1 to 12, wherein: The thickness h of the body (10) is 0.1 mm-1.5 mm.

14. A battery pack (200), wherein: include: A plurality of battery cells (201), each of the battery cells (201) being provided with an electrode terminal; According to any one of claims 1 to 13, the electrode connecting portion (11) is connected to the electrode terminal.

15. The battery pack according to claim 14, wherein: The body (10) is provided with at least one through-hole (13) penetrating along the thickness direction thereof. The temperature rise rate dT / dt of the fuse part (12) satisfies the following relationship: Wherein, ρ resistivity is the resistivity of the fuse part (12), ρ density is the density of the fuse part (12), Cp is the specific heat capacity of the fuse part (12), S is the flow area of ​​the fuse part (12), d1 is the distance between the side of the through opening (13) close to the electrode connecting part (11) and the side away from the electrode connecting part (11), and n is the number of the battery cells arranged in parallel.

16. The battery pack according to claim 15, wherein: There is one fuse part (12), and the flow area S of the fuse part (12) is: 0.5 mm 2 ≤S=l*h≤10mm 2 , wherein l is the minimum width of the fuse portion (12), and h is the thickness of the body (10).

17. The battery pack according to claim 15, wherein: There are a plurality of fuse parts (12), and the plurality of fuse parts (12) are arranged at intervals. The relationship between the area S of the fuse part (12) and the thickness h of the body (10) is: 0.5 mm 2 ≤S=L*h≤(n-1)×10mm 2 , wherein L is the sum of the minimum widths of the plurality of fuse parts (12), n is the number of battery cells (201) arranged in parallel, and h is the thickness of the body (10).

18. The battery pack (200) according to any one of claims 14 to 17, wherein: The electrode terminal is a pole or a shell of the battery cell (201).

19. An electrical device, wherein: A battery pack (200) comprising any one of claims 14-18.

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