Single battery and battery pack

Abstract

The utility model discloses a single battery and a battery pack, and belongs to the technical field of batteries, the single battery has a first direction and a second direction which are intersected, the single battery comprises a pole, a tab and a connecting piece, and the pole is connected with the tab through the connecting piece. The connecting piece comprises a plurality of first side faces arranged at intervals in the first direction, a plurality of second side faces arranged at intervals in the second direction and a plurality of chamfered faces, each chamfered face is arranged between the first side face and the second side face which are adjacent, and the first side faces are connected with the second side faces through the chamfered faces. Wherein in the first direction, the chamfered surface has the maximum size R1, in the second direction, the chamfered surface has the maximum size R2, R1 is larger than or equal to 0.1 mm and smaller than or equal to 50 mm, and R2 is larger than or equal to 0.1 mm and smaller than or equal to 50 mm. By limiting the maximum sizes R1 and R2 of the chamfered surfaces, stress concentration can be reduced while the strength of the connecting piece is met, and the connecting piece is prevented from cracking, breaking or falling off under vibration impact.

Description

Technical Field

[0001] The present application belongs to the field of battery technology, and specifically relates to a single cell and a battery pack. Background Art

[0002] In some single battery cells, the tabs are connected to the poles through connecting plates, where the cross-section transition positions around the connecting plates are usually designed as right-angle transitions. The right-angle transition positions are stress concentration points. The single battery cells may be subjected to vibration shocks during use. Vibration shocks may cause the cross-section transition positions around them to bear greater forces, increasing the risk of cracking and breakage, and leading to abnormal internal resistance of the battery cells. Utility Model Content

[0003] Purpose of the utility model: The embodiments of the present application provide a single cell and a battery pack, aiming to solve the technical problem that stress concentration at the transition position of the cross section around the connecting piece makes it easy to crack or break due to vibration impact.

[0004] Technical solution: The embodiment of the present application provides a single battery, which includes a pole, a tab, and a connecting piece, wherein the pole is connected to the tab through the connecting piece;

[0005] The connecting piece has a first direction and a second direction intersecting each other, and includes a plurality of first side surfaces spaced apart along the first direction, a plurality of second side surfaces spaced apart along the second direction, and a plurality of chamfered surfaces, each chamfered surface being disposed between adjacent first and second side surfaces, and the first side surfaces being connected to the second side surfaces via the chamfered surfaces;

[0006] The chamfered surface has a maximum size R1 along the first direction, and a maximum size R2 along the second direction, satisfying: 0.1 mm ≤ R1 ≤ 50 mm, 0.1 mm ≤ R2 ≤ 50 mm.

[0007] In some embodiments, along the first direction, the maximum dimension R1 of at least one chamfered surface of the connecting piece is different from the maximum dimension R1 of at least another chamfered surface; or, along the second direction, the maximum dimension R2 of at least one chamfered surface of the connecting piece is different from the maximum dimension R2 of at least another chamfered surface.

[0008] In some embodiments, there are multiple poles, tabs, and connecting plates, and each connecting plate connects one pole and one tab; along the first direction, the maximum dimension R1 of at least one chamfered surface of one connecting plate is different from that of the chamfered surface of another connecting plate; or, along the second direction, the maximum dimension R2 of at least one chamfered surface of one connecting plate is different from that of the chamfered surface of another connecting plate.

[0009] In some embodiments, there are multiple poles, tabs, and connecting pieces, each connecting piece connects one pole and one tab; at least one chamfered surface of one connecting piece has a different shape from that of another connecting piece.

[0010] In some embodiments, the chamfered surface is an inclined surface inclined to the first direction and the second direction, and / or the chamfered surface is a curved surface.

[0011] In some embodiments, the first side surface and / or the second side surface is provided with a notch, the notch has a maximum dimension A1 along the first direction, and the notch has a maximum dimension A2 along the second direction, satisfying: 0.05mm≤A1≤10mm, 0.05mm≤A2≤10mm.

[0012] In some embodiments, the connecting piece has a third direction, the third direction corresponds to the thickness direction of the connecting piece, and the third direction intersects the first direction and the second direction respectively;

[0013] The connecting plate also includes a second connecting portion and a third side surface and a fourth side surface arranged at intervals along the third direction, the third side surface is connected to the pole, the fourth side surface is connected to the pole ear, the first side surface and the second side surface are both arranged between the third side surface and the fourth side surface, and the fourth side surface is connected to the first side surface through the second connecting portion.

[0014] In some embodiments, along the third direction, the second connecting portion has a maximum dimension r, and the connecting piece has a maximum dimension B, satisfying: 0.05≤r / B≤0.9.

[0015] In some embodiments, a maximum dimension B of the connecting piece along the third direction satisfies: 0.1 mm ≤ B ≤ 5 mm.

[0016] Accordingly, an embodiment of the present application provides a battery pack including the above-mentioned single battery.

[0017] Beneficial effects: A single cell battery according to an embodiment of the present application has a first direction and a second direction intersecting each other, and the single cell battery includes a pole, a tab, and a connecting piece, and the pole is connected to the tab via the connecting piece. The connecting piece includes a plurality of first side surfaces spaced apart along the first direction, a plurality of second side surfaces spaced apart along the second direction, and a plurality of chamfered surfaces, each chamfered surface being disposed between adjacent first and second side surfaces, and the first side surface being connected to the second side surface via the chamfered surface. In particular, along the first direction, the chamfered surface has a maximum dimension R1, and along the second direction, the chamfered surface has a maximum dimension R2, satisfying the following: 0.1mm≤R1≤50mm, 0.1mm≤R2≤50mm. By limiting the maximum dimensions R1 and R2 of the chamfered surfaces, stress concentration can be reduced while satisfying the strength of the connecting piece, thereby preventing the connecting piece from cracking, breaking, or falling off under vibration impact.

[0018] The battery pack of the embodiment of the present application includes the above-mentioned single battery, so the battery pack can have all the technical features and beneficial effects of the above-mentioned single battery, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

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

[0021] Figure 2 This is an exploded view of a single cell according to an embodiment of the present application;

[0022] Figure 3 This is a schematic structural diagram of a top cover according to an embodiment of the present application;

[0023] Figure 4 This is a schematic structural diagram of the first connecting piece according to an embodiment of the present application;

[0024] Figure 5 is a top view of the first connecting piece of an embodiment of the present application;

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

[0026] Figure 7 is a top view of the second connecting piece of the embodiment of the present application;

[0027] Figure 8 yes Figure 7 Magnified view of part C;

[0028] Figure 9 This is a schematic structural diagram of a third connecting piece according to an embodiment of the present application;

[0029] Figure 10 is a top view of the third connecting piece according to an embodiment of the present application;

[0030] Figure 11 yes Figure 10 Magnified view of the D part;

[0031] Figure 12 is a front view of a third connecting piece according to an embodiment of the present application;

[0032] Figure 13 yes Figure 12 Enlarged view of part E.

[0033] Figure numerals: 1, pole; 2, pole ear; 3, connecting piece; 4, notch; 30, first side; 31, second side; 32, chamfered surface; 33, second connecting portion; 34, third side; 35, fourth side; 100, top cover; 200, battery cell; 320, inclined surface; 321, curved surface; X, first direction; Y, second direction; Z, third direction. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0035] In the description of the present application, it should be understood that the terms "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "multiple" means two or more, and at least one means one, two or more, unless otherwise clearly and specifically defined. In the description of this application, "vertical" means completely vertical at 90° or almost completely vertical, for example, an angle within the range of 80° to 100° is considered vertical. Similarly, "parallel" means completely parallel or almost completely parallel, for example, an angle within 10° of completely parallel is considered parallel.

[0036] In some single battery cells, the tabs are connected to the poles through connecting plates, where the cross-section transition positions around the connecting plates are usually designed as right-angle transitions. The right-angle transition positions are stress concentration points. The single battery cells may be subjected to vibration shocks during use. Vibration shocks may cause the cross-section transition positions around them to bear greater forces, increasing the risk of cracking and breakage, and leading to abnormal internal resistance of the battery cells.

[0037] In view of this, an embodiment of the present application provides a single battery, which includes a shell, a battery cell, a pole, a tab, and a connecting piece. The shell encloses a receiving cavity, and the battery cell, the pole, the tab, and the connecting piece are arranged in the receiving cavity. The pole tab is provided on the side of the battery cell close to the pole, and the pole is connected to the tab via the connecting piece. The connecting piece has a first direction and a second direction that intersect, and the connecting piece includes a plurality of first side surfaces spaced apart along the first direction, a plurality of second side surfaces spaced apart along the second direction, and a plurality of chamfered surfaces, each chamfered surface being provided between adjacent first and second side surfaces, and the first side surface being connected to the second side surface via the chamfered surface. In particular, along the first direction, the chamfered surface has a maximum dimension R1, and along the second direction, the chamfered surface has a maximum dimension R2, satisfying the following: 0.1mm≤R1≤50mm, 0.1mm≤R2≤50mm. By limiting the maximum dimensions R1 and R2 of the chamfered surfaces, stress concentration can be reduced while meeting the strength of the connecting piece, thereby preventing the connecting piece from cracking, breaking, or falling off under vibration impact.

[0038] The following describes the single cell and battery pack of the present application in detail with reference to the accompanying drawings. The features of the following embodiments and implementations can be combined with each other unless they conflict.

[0039] Figure 1 It is a structural schematic diagram of a single cell according to an embodiment of the present application. Figure 2 This is an exploded diagram of a single cell according to an embodiment of the present application. Figure 3 It is a structural schematic diagram of a top cover 100 according to an embodiment of the present application.

[0040] Figure 4 It is a structural diagram of the first connecting piece 3 of the embodiment of the present application. Figure 5 It is a top view of the first connecting piece 3 of the embodiment of the present application. Figure 6 It is a schematic structural diagram of the second connecting piece 3 of the embodiment of the present application. Figure 7 It is a top view of the second connecting piece 3 of the embodiment of the present application. Figure 8 yes Figure 7 Enlarged view of part C. Figure 9 It is a structural diagram of the third connecting piece 3 of the embodiment of the present application. Figure 10 It is a top view of the third connecting piece 3 of the embodiment of the present application. Figure 11 yes Figure 10 Enlarged view of part D. Figure 12 It is a front view of the third connecting piece 3 of the embodiment of the present application. Figure 13 yes Figure 12 Enlarged view of part E.

[0041] refer to Figures 1 to 13A single battery cell according to an embodiment of the present application includes a housing (not shown), a battery cell 200, a pole 1, a tab 2, and a connecting piece 3. The housing encloses a receiving cavity (not shown). The battery cell 200, the pole 1, the tab 2, and the connecting piece 3 are disposed within the receiving cavity. The pole tab 2 is disposed on the side of the battery cell 200 close to the pole 1, and the pole 1 is connected to the tab 2 via the connecting piece 3. The pole 1 can be welded to the tab 2 via the connecting piece 3 to electrically connect the pole 1 to the battery cell 200. The connecting piece 3 has a first direction X and a second direction Y intersecting therewith. The connecting piece 3 includes a plurality of first side surfaces 30 spaced apart along the first direction X, a plurality of second side surfaces 31 spaced apart along the second direction Y, and a plurality of chamfered surfaces 32. Each chamfered surface 32 is disposed between adjacent first side surfaces 30 and second side surfaces 31. The first side surface 30 is connected to the second side surface 31 via the chamfered surface 32. The chamfered surface 32 has a maximum dimension R1 along the first direction X, and has a maximum dimension R2 along the second direction Y, satisfying the following conditions: 0.1 mm ≤ R1 ≤ 50 mm, 0.1 mm ≤ R2 ≤ 50 mm.

[0042] It should be noted that the chamfered surface 32 is a surface formed after the connecting piece 3 is chamfered. The maximum dimension R1 of the chamfered surface 32 along the first direction X refers to the dimension of the chamfer of the connecting piece 3 in the first direction X. The maximum dimension R2 of the chamfered surface 32 along the second direction Y refers to the dimension of the chamfer of the connecting piece 3 in the second direction X.

[0043] Exemplarily, the maximum dimension R1 of the chamfered surface 32 can be any value of 0.1mm, 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm, 34mm, 36mm, 38mm, 40mm, 42mm, 44mm, 46mm, 48mm, or 50mm, or a range between any two values. The maximum dimension R2 of the chamfered surface 32 can be any value selected from the group consisting of 0.1mm, 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm, 34mm, 36mm, 38mm, 40mm, 42mm, 44mm, 46mm, 48mm, and 50mm, or a range between any two of these values. The first direction X represents the width of the connecting piece 3, and the second direction Y represents the length of the connecting piece 3. The first direction X and the second direction Y are perpendicular to each other. By limiting the maximum dimensions R1 and R2 of the chamfered surface 32, stress concentration can be reduced while ensuring the strength of the connecting piece 3, thereby preventing the connecting piece 3 from cracking, breaking, or falling off due to vibration and impact. Furthermore, the provision of the chamfered surface 32 can avoid the risk of severing the tab 2, thereby preventing issues such as affecting the capacity of the battery cell 200 and causing abnormal internal resistance of the battery cell 200, thereby improving the safety and stability of the single battery cell.

[0044] In the embodiment of the present application, the connecting pieces 3 with chamfered surfaces 32 of different sizes are connected to the tabs 2 respectively by ultrasonic welding, and a vibration test is performed to detect whether the connecting pieces 3 are cracked or detached. The specific test results are shown in Table 1.

[0045] Table 1:

[0046] <![CDATA[R1 / mm]]> <![CDATA[R2 / mm]]> Vibration test results Cracking probability Example 1 0.1 0.1 satisfy Cracking probability <1% Example 2 50 50 satisfy Cracking probability <1% Comparative Example 1 0 0 Dissatisfied Cracking probability>1% Comparative Example 2 0.05 0.05 Dissatisfied Cracking probability>1% Comparative Example 3 60 60 Dissatisfied Cracking probability <1%

[0047] The vibration tests in the table above were conducted in accordance with test standard 8.2.1 of the national standard GB 38031-2020, Safety Requirements for Power Batteries for Electric Vehicles. The vibration test results can be used to determine whether connector 3 will crack or fall off during use. This can be determined by directly observing or using 2D projection to detect holes or tears in connector 3.

[0048] For example, 100 samples were prepared. The connecting piece 3 was observed directly or using two-dimensional projection to determine if it had holes or tears. The cracking probability was calculated by calculating the proportion of cracked connecting pieces 3 to the total number of samples. If the cracking probability was less than 1%, it could be concluded that the strength and connection stability of the connecting piece 3 met the requirements.

[0049] Referring to Table 1, Comparative Examples 1 and 2 do not meet the requirements of 0.1mm≤R1≤50mm and 0.1mm≤R2≤50mm, and the probability of cracking of the connecting piece 3 under vibration and impact is greater than 1%. Specifically, in Comparative Example 1, the connecting piece 3 does not have a chamfered surface 32, and the connecting piece 3 has a right-angle transition on all sides. In Comparative Example 2, the chamfered surfaces 32 provided on all sides of the connecting piece 3 are too small, making it impossible to effectively disperse stress. The transition points around the connecting piece 3 are stress concentration points. When the transition points around the connecting piece 3 are right-angle transitions, or when the chamfered surfaces 32 at the transition points around the connecting piece 3 are too small, there is a risk of cracking or even breaking under vibration and impact, resulting in abnormal internal resistance of the battery cell 200. In Comparative Example 3, the maximum dimension R of the chamfered surface 32 is greater than 50mm. The excessive size of the chamfered surface 32 reduces the effective connection area of the connecting piece 3, and there is a risk of the connecting piece 3 falling off, thereby reducing the strength and connection stability of the connecting piece 3. In Examples 1 and 2, the requirements of 0.1 mm ≤ R1 ≤ 50 mm and 0.1 mm ≤ R2 ≤ 50 mm are met, and the probability of cracking of the connecting piece 3 under vibration and impact is less than 1%. By limiting the maximum dimensions R1 and R2 of the chamfered surface 32 to 0.1 mm ≤ R1 ≤ 50 mm and 0.1 mm ≤ R2 ≤ 50 mm, the strength and stability of the connecting piece 3 are maintained, stress concentration is reduced, and the risk of cracking or falling off of the connecting piece 3 under vibration and impact is reduced, thereby improving the safety and stability of the single battery cell.

[0050] In some embodiments, the chamfered surface 32 is an inclined surface 320 inclined to the first direction X and the second direction Y. Figure 7 In other embodiments, the chamfered surface 32 is a curved surface 321, referring to Figure 5 In other embodiments, part of the chamfered surface 32 of a connecting piece 3 is an inclined surface 320 inclined to the first direction X and the second direction Y, and the remaining chamfered surface 32 is a curved surface 321. Figure 10 In the embodiments of the present application, chamfered surfaces 32 of different shapes can be provided as required, thereby reducing stress concentration while meeting the strength of the connecting piece 3, preventing the connecting piece 3 from cracking, breaking or falling off under vibration and impact, and improving the safety and stability of the single battery. This application does not impose any restrictions on this.

[0051] In some embodiments, along the first direction X, the maximum dimension R1 of at least one chamfered surface 32 of the connecting piece 3 is different from the maximum dimension R1 of at least another chamfered surface 32. In other embodiments, along the second direction Y, the maximum dimension R2 of at least one chamfered surface 32 of the connecting piece 3 is different from the maximum dimension R2 of at least another chamfered surface 32. Figure 5In the illustrated embodiment, the maximum dimension R1 of one chamfered surface 32 of the connecting piece 3 is different from the maximum dimensions R1 of the other three chamfered surfaces 32, and the maximum dimension R2 of one chamfered surface 32 of the connecting piece 3 is different from the maximum dimensions R2 of the other three chamfered surfaces 32. This arrangement can achieve a fool-proof effect on the front and back sides of the connecting piece 3, reduce the risk of assembly errors, and improve assembly accuracy and efficiency.

[0052] In some embodiments, there are multiple poles 1, multiple tabs 2, and multiple connecting tabs 3, and each connecting tab 3 connects one pole 1 and one tab 2. It is understood that the pole 1 may include a positive pole 1 and a negative pole 1, the tab 2 may include a positive tab 2 and a negative tab 2, and the connecting tab 3 may also include a positive connecting tab 3 and a negative connecting tab 3, wherein the positive connecting tab 3 is connected to the positive pole 1 and the positive tab 2, respectively, and the negative connecting tab 3 is connected to the negative pole 1 and the negative tab 2, respectively, by ultrasonic welding. Typically, the positive connecting tab 3 and the negative connecting tab 3 are made of different materials and have different thicknesses, but they are not easily distinguished during assembly.

[0053] In some embodiments, along the first direction X, at least one chamfered surface 32 of one connecting piece 3 has a different maximum dimension R1 from that of the chamfered surface 32 of another connecting piece 3. In other embodiments, at least one chamfered surface 32 of one connecting piece 3 has a different maximum dimension R2 from that of the chamfered surface 32 of another connecting piece 3. Figure 5 and Figure 7 In the embodiment shown, by providing chamfered surfaces 32 of different sizes on the positive electrode connecting piece 3 and the negative electrode connecting piece 3, a fool-proofing effect of the positive electrode connecting piece 3 and the negative electrode connecting piece 3 can be achieved, which facilitates rapid identification and differentiation of the positive electrode connecting piece 3 and the negative electrode connecting piece 3 during the assembly process, thereby improving the accuracy and efficiency of assembly.

[0054] In some embodiments, there are multiple poles 1, tabs 2, and connecting pieces 3, and each connecting piece 3 connects one pole 1 and one tab 2; at least one chamfered surface 32 of one connecting piece 3 has a different shape from the chamfered surface 32 of another connecting piece 3. It is understandable that the pole 1 may include a positive pole 1 and a negative pole 1, the tab 2 may include a positive tab 2 and a negative tab 2, and the connecting piece 3 may also include a positive connecting piece 3 and a negative connecting piece 3, wherein the positive connecting piece 3 is respectively connected to the positive pole 1 and the positive tab 2, and the negative connecting piece 3 is respectively connected to the negative pole 1 and the negative tab 2 by ultrasonic welding. Usually, the positive connecting piece 3 and the negative connecting piece 3 are made of different materials and have different thicknesses, but they are not easy to distinguish during the assembly process. Figure 10In the illustrated embodiment, by providing chamfered surfaces 32 of different shapes on the positive electrode connecting tab 3 and the negative electrode connecting tab 3, for example, at corresponding positions on the positive electrode connecting tab 3 and the negative electrode connecting tab 3, one chamfered surface 32 is provided as an inclined surface 320, and the other chamfered surface 32 is provided as a curved surface 321, thereby achieving a foolproof effect on the positive electrode connecting tab 3 and the negative electrode connecting tab 3, facilitating rapid identification and differentiation of the positive electrode connecting tab 3 and the negative electrode connecting tab 3 during the assembly process, thereby improving the accuracy and efficiency of assembly.

[0055] exist Figure 10 and Figure 11 In the illustrated embodiment, the first side surface 30 is provided with a notch 4 , the notch 4 has a maximum dimension A1 along the first direction X, and the notch 4 has a maximum dimension A2 along the second direction Y, satisfying: 0.05 mm ≤ A1 ≤ 10 mm, 0.05 mm ≤ A2 ≤ 10 mm.

[0056] In other embodiments, the second side surface 31 is provided with a notch 4 , and the notch 4 has a maximum dimension A1 along the first direction X, and the notch 4 has a maximum dimension A2 along the second direction Y, satisfying: 0.05 mm ≤ A1 ≤ 10 mm, 0.05 mm ≤ A2 ≤ 10 mm.

[0057] In other embodiments, the first side surface 30 and the second side surface 31 are provided with a notch 4, the notch 4 has a maximum dimension A1 along the first direction X, and the notch 4 has a maximum dimension A2 along the second direction Y, satisfying: 0.05mm≤A1≤10mm, 0.05mm≤A2≤10mm.

[0058] For example, the maximum dimension A1 of the notch 4 can be any value selected from the group consisting of 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, or 10 mm, or a range between any two values. The maximum dimension A2 of the notch 4 can be any value selected from the group consisting of 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, or 10 mm, or a range between any two values. The connecting piece 3 is formed by a stamping process and has high strength and stability. Specifically, the connecting piece 3 is punched and formed by the following steps: the first step is to punch a positioning hole on the material strip. The second step is to punch out the shape and reserve local material residue on the peripheral side of the connecting piece 3. The third step is to cut off the waste material on the peripheral side of the connecting piece 3, and a notch 4 is formed on the peripheral side of the connecting piece 3. The notch 4 is required for the process of continuously punching a plurality of connecting pieces 3. By providing the notch 4, the cutting length can be reduced, which is conducive to reducing burrs and preventing burrs on the first side 30 or the second side 31 of the connecting piece 3 from piercing the tab 2, resulting in voltage anomalies caused by tearing or breaking of the tab 2. In addition, providing the notch 4 can shorten the punching length of the mold and increase the service life of the mold.

[0059] In the embodiment of the present application, the connecting pieces 3 with notches 4 of different sizes are connected to the tabs 2 respectively by ultrasonic welding, and the burr height on the connecting piece 3 is observed by two-dimensional projection. The specific test results are shown in Table 2.

[0060] Table 2:

[0061]

[0062]

[0063] The vibration tests in the table above were conducted in accordance with test standard 8.2.1 of the national standard GB 38031-2020, Safety Requirements for Power Batteries for Electric Vehicles. The vibration test results can be used to determine whether connector 3 will break or fall off during welding or use.

[0064] For example, 100 samples are prepared and the burr height on the connecting piece 3 is observed through two-dimensional projection. The presence of holes or tears on the tab 2 is also observed directly or through two-dimensional projection to determine whether the tab 2 is punctured by the burr. The probability of tab 2 puncture is calculated by calculating the proportion of tabs 2 punctured by burrs to the total number of samples. If the probability of tab 2 puncture is less than 1%, it can be concluded that the strength and connection stability of the connecting piece 3 meet the requirements.

[0065] Referring to Table 2, Comparative Examples 5 and 6 do not meet the requirements of 0.05mm≤A1≤10mm and 0.05mm≤A2≤10mm, and the burr height is greater than 0.05mm, thereby increasing the probability of puncturing the tab 2. Specifically, in Comparative Example 1, the connecting piece 3 is not provided with a notch 4, the cutting length is long, the burrs generated by punching are more numerous, and the burr height exceeds 0.05mm, resulting in an increased probability of burrs piercing the tab 2, leading to an increased risk of the tab 2 tearing or breaking, causing voltage anomalies. In Comparative Example 2, the maximum dimensions A1 and A2 of the notch 4 provided on the first side 30 or the second side 31 of the connecting piece 3 are both less than 0.05mm. The excessively small size of the notch 4 increases the difficulty of the punching process, potentially leading to incomplete or uneven cutting or a large number of burrs. Moreover, the burr height exceeds 0.05mm, which also increases the probability of burrs piercing the tab 2, leading to an increased risk of the tab 2 tearing or breaking, causing voltage anomalies, and preventing effective stress dispersion. Comparative Example 7 does not meet 0.05mm≤A1≤10mm and 0.05mm≤A2≤10mm. Specifically, in Comparative Example 7, the maximum dimensions A1 and A2 of the notch 4 set on the first side 30 or the second side 31 of the connecting piece 3 are both greater than 10mm, the burr height is less than 0.05mm, and the probability of piercing the tab 2 is less than 1%, which meets the requirements. However, an excessively large notch 4 will weaken the structural integrity and strength of the connecting piece 3, and may easily cause the connecting piece 3 to break or fall off during welding or use, thereby affecting the safety and reliability of the connecting piece 3. Examples 3 and 4 satisfy 0.05mm≤A1≤10mm, 0.05mm≤A2≤10mm, and compared with Comparative Examples 5 and 6, the height of the burrs generated on the connecting piece 3 of Examples 3 and 4 is less than 0.05mm, and the probability of piercing the tab 2 is less than 1%. While avoiding the voltage abnormality caused by the burrs piercing the tab 2 and causing the tab 2 to tear or break, the strength of the connecting piece 3 can be improved, thereby improving the safety and reliability of the connecting piece 3.

[0066] In some embodiments, the shape of the notch 4 can be rectangular, such as Figure 8 In other embodiments, the shape of the notch 4 can be an arc, such as Figure 11In the embodiment of the present application, the notch 4 can be provided with different shapes according to the requirements, and the present application does not limit this.

[0067] exist Figure 12 and Figure 13 In the illustrated embodiment, the connecting piece 3 has a third direction Z, which corresponds to the thickness direction of the connecting piece 3. The third direction Z intersects the first direction X and the second direction Y, respectively, and is perpendicular to the first direction X and the second direction Y. The connecting piece 3 also includes a second connecting portion 33 and a third side surface 34 and a fourth side surface 35 spaced apart along the third direction Z. The third side surface 34 is connected to the electrode 1, and the fourth side surface 35 is connected to the tab 2. The first side surface 30 and the second side surface 31 are both disposed between the third side surface 34 and the fourth side surface 35. In some embodiments, the fourth side surface 35 is connected to the first side surface 30 via the second connecting portion 33. The contact surface between the tab 2 and the fourth side surface 35 of the connecting piece 3 is smaller than the surface area of the fourth side surface 35. Typically, the tab 2 does not contact the contour of the second side surface 31. Therefore, the second connecting portion 33 can be provided only between the fourth side surface 35 and the first side surface 30 as a transition. This avoids the sharp contours of the connecting piece 3 that could cause the tab 2 to be cut or break, leading to voltage anomalies, while simplifying the manufacturing process. In other embodiments, the fourth side surface 35 is connected to the first side surface 30 and the second side surface 31 through the second connecting portion 33 , which can prevent the sharp contours of the connecting piece 3 from cutting the tab 2 or causing voltage abnormalities due to breakage.

[0068] exist Figure 13In the illustrated embodiment, along the third direction Z, the second connecting portion 33 has a maximum dimension r, and the connecting piece 3 has a maximum dimension B, satisfying the following conditions: 0.05 ≤ r / B ≤ 0.9, and 0.1 mm ≤ B ≤ 5 mm. The ratio of the maximum dimension r of the second connecting portion 33 along the third direction Z to the maximum dimension B of the connecting piece 3 along the third direction Z can be any value selected from the group consisting of 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, and 0.9, or a range between any two of these values. The maximum dimension B of the connecting piece 3 along the third direction Z can be any value selected from the group consisting of 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm, or a range between any two of these values. If the ratio of the maximum dimension r of the second connecting portion 33 along the third direction Z to the maximum dimension B of the connecting piece 3 along the third direction Z is too small, there may be a risk that the surrounding contours of the connecting piece 3 are too sharp, causing the tab 2 to be cut or broken, resulting in voltage anomalies. If the ratio of the maximum dimension r of the second connecting portion 33 along the third direction Z to the maximum dimension B of the connecting piece 3 along the third direction Z is too large, there may be a risk that the second connecting portion 33 occupies too much space, resulting in a reduction in the strength of the connecting piece 3. By limiting the ratio of the maximum dimension r of the second connecting portion 33 along the third direction Z to the maximum dimension B of the connecting piece 3 along the third direction Z to satisfy 0.05≤r / B≤0.9, it is possible to maintain the strength of the connecting piece 3 while avoiding voltage anomalies caused by the surrounding contours of the connecting piece 3 being too sharp, causing the tab 2 to be cut or broken, further improving the safety and reliability of the connecting piece 3.

[0069] Accordingly, an embodiment of the present application provides a battery pack, which includes the above-mentioned single cell. The single cell includes a pole, a tab and a connecting piece, and the pole is connected to the tab through the connecting piece. The connecting piece includes a plurality of first side surfaces spaced apart along the first direction, a plurality of second side surfaces spaced apart along the second direction, and a plurality of chamfered surfaces, each chamfered surface is arranged between adjacent first and second side surfaces, and the first side surface is connected to the second side surface through the chamfered surface. In which, along the first direction, the chamfered surface has a maximum dimension R1, and along the second direction, the chamfered surface has a maximum dimension R2, satisfying: 0.1mm≤R1≤50mm, 0.1mm≤R2≤50mm. By limiting the maximum dimensions R1 and R2 of the chamfered surfaces, stress concentration can be reduced while meeting the strength of the connecting piece, thereby preventing the connecting piece from cracking, breaking or falling off under vibration impact.

[0070] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0071] The above is a detailed introduction to a single cell and a battery pack provided in the embodiments of the present application, and specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application; ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A single battery, characterized in that: The single battery comprises a pole, a tab and a connecting piece, wherein the pole is connected to the tab via the connecting piece; The connecting piece has a first direction and a second direction intersecting each other, and includes a plurality of first side surfaces spaced apart along the first direction, a plurality of second side surfaces spaced apart along the second direction, and a plurality of chamfered surfaces, wherein the chamfered surfaces are disposed between adjacent first side surfaces and second side surfaces, and the first side surfaces are connected to the second side surfaces via the chamfered surfaces; Wherein, along the first direction, the chamfered surface has a maximum size R1, and along the second direction, the chamfered surface has a maximum size R2, satisfying: 0.1 mm ≤ R1 ≤ 50 mm, 0.1 mm ≤ R2 ≤ 50 mm.

2. The single cell according to claim 1, characterized in that: Along the first direction, the maximum dimension R1 of at least one of the chamfered surfaces of the connecting piece is different from the maximum dimension R1 of at least another chamfered surface; or Along the second direction, a maximum dimension R2 of at least one of the chamfered surfaces of the connecting piece is different from a maximum dimension R2 of at least another of the chamfered surfaces.

3. The single cell according to claim 1, characterized in that: There are multiple poles, multiple tabs, and multiple connecting pieces, and each connecting piece is connected to one pole and one tab; Along the first direction, a maximum dimension R1 of at least one chamfered surface of one connecting piece is different from a maximum dimension R1 of a chamfered surface of another connecting piece; or Along the second direction, a maximum dimension R2 of at least one chamfered surface of one connecting piece is different from a maximum dimension R2 of the chamfered surface of another connecting piece.

4. The single cell according to claim 1, characterized in that: There are multiple poles, multiple tabs, and multiple connecting pieces, and each connecting piece is connected to one pole and one tab; The shape of at least one chamfered surface of one connecting piece is different from that of the chamfered surface of another connecting piece.

5. The single cell according to claim 1, characterized in that: The chamfered surface is an inclined surface inclined to the first direction and the second direction, and / or the chamfered surface is a curved surface.

6. The single cell according to claim 1, characterized in that: The first side surface and / or the second side surface is provided with a notch (4), the notch (4) has a maximum dimension A1 along the first direction, and the notch (4) has a maximum dimension A2 along the second direction, satisfying: 0.05mm≤A1≤10mm, 0.05mm≤A2≤10mm.

7. The single cell according to claim 1, characterized in that: The connecting piece has a third direction, the third direction corresponds to the thickness direction of the connecting piece, and the third direction intersects with the first direction and the second direction respectively; The connecting piece also includes a second connecting portion and a third side surface and a fourth side surface arranged at intervals along the third direction, the third side surface is connected to the pole, the fourth side surface is connected to the pole ear, the first side surface and the second side surface are both arranged between the third side surface and the fourth side surface, and the fourth side surface is connected to the first side surface through the second connecting portion.

8. The single cell according to claim 7, characterized in that: Along the third direction, the second connecting portion has a maximum size r, and the connecting piece has a maximum size B, satisfying: 0.05≤r / B≤0.

9.

9. The single cell according to claim 8, characterized in that: The maximum dimension B of the connecting piece along the third direction satisfies: 0.1 mm ≤ B ≤ 5 mm.

10. A battery pack, characterized in that: The invention comprises the single cell according to any one of claims 1 to 9.

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