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 comprises a shell, an electrode assembly, a cover plate, a first insulating part and a pressing plate, the pressing plate is arranged on one side, far away from the electrode assembly, of the first insulating part and surrounds a pole; the pressing plate comprises a first body and a first step, the first body and the pole are welded to form a welding mark, the first step is connected to the side, away from the electrode assembly, of the first body, the minimum distance between the welding mark and the first step is A mm, and A is larger than or equal to 0.2 and smaller than or equal to 10; the pole comprises a second body and a second step, the second body and the pressing plate are welded to form a welding mark, the second step is connected to the side, away from the electrode assembly, of the second body, the minimum distance between the welding mark and the second step is B mm, and B is larger than or equal to 0.2 and smaller than or equal to 10. The distances between the welding marks and the first step and the second step are limited, so that explosion points or insufficient welding can be avoided during welding, the welding effect can be ensured, the welding reject ratio is reduced, the tensile strength of the pole and the pressing plate is improved, and the safety of the single battery is improved.

Description

Technical Field

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

[0002] As power battery technology matures and is widely used in electric vehicles and energy storage, the performance and safety requirements for power batteries are increasing. Batteries typically feature rivets that connect to the terminals. Connecting tabs are welded to the rivets and terminals to enable series and parallel connection of the cells. However, this process is complex, and the assembly reliability of the terminals and rivets is poor, making them prone to poor welding. 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 problems of complex assembly process of riveted parts and poles, poor reliability, and easy occurrence of poor welding.

[0004] Technical solution: This embodiment of the present application provides a single battery, including:

[0005] A housing having a receiving cavity;

[0006] The electrode assembly is disposed in the accommodating cavity;

[0007] A cover plate is connected to the shell and covers the accommodating cavity, and the cover plate is provided with a pole hole;

[0008] The pole is inserted into the pole hole and is electrically connected to the electrode assembly;

[0009] A first insulating member is provided on a side of the cover plate away from the electrode assembly and surrounds the electrode column;

[0010] A pressure plate is provided on a side of the first insulating member away from the electrode assembly and surrounds the electrode column;

[0011] The pressure plate includes a first body and a first step, the first body is welded to the pole to form a weld mark, the first step is connected to the side of the first body away from the electrode assembly, and the first step is spaced apart from the pole, the minimum spacing between the weld mark and the first step is A mm, and satisfies: 0.2≤A≤10; and / or, the pole includes a second body and a second step, the second body is welded to the pressure plate to form a weld mark, the second step is connected to the side of the second body away from the electrode assembly, and the second step is spaced apart from the pressure plate, the minimum spacing between the weld mark and the second step is B mm, and satisfies: 0.2≤B≤10.

[0012] In some embodiments, the first body includes a connecting portion and a limiting portion connected to each other, the first step is connected to the connecting portion, the limiting portion is arranged on a side of the second body away from the electrode assembly, and the limiting portion and the second body are welded to form a weld mark.

[0013] In some embodiments, the electrode includes a first surface and a second surface that are oppositely arranged in the thickness direction of the cover plate, the first surface is the surface of the electrode farthest from the electrode assembly in the thickness direction, and the second surface is the surface of the electrode closest to the electrode assembly in the thickness direction. The area of the first surface is S1 mm 2 , the area of the second surface is S2 mm 2 , satisfying: 0.01≤S1 / S2≤20.

[0014] In some embodiments, the welding depth between the pressure plate and the pole is C mm, the maximum dimension of the pole along the thickness direction of the cover plate is D mm, and the following conditions are satisfied: 0.005≤C / D≤0.89.

[0015] In some embodiments, the single battery further satisfies: 0.1≤C≤5.

[0016] In some embodiments, the single battery further satisfies: 1.5≤D≤20.

[0017] In some embodiments, the weld width between the pressure plate and the pole is E mm, satisfying the following: 0.1≤E≤5.

[0018] In some embodiments, the maximum dimension of the first step along the thickness direction of the cover plate is F mm, satisfying: 0.5≤F≤10.

[0019] In some embodiments, the minimum distance between the first step and the second step is G mm, satisfying: 0.5≤G≤10.

[0020] In some embodiments, the electrode post has a positioning hole at its center, and the positioning hole is disposed on a side of the electrode post away from the electrode assembly;

[0021] The maximum dimension of the positioning hole along the length direction of the cover plate is H mm, and the maximum dimension of the positioning hole along the thickness direction of the cover plate is I mm. The length direction intersects with the thickness direction and satisfies: 0.5≤H≤10, 0.1≤I≤10.

[0022] In some embodiments, the pressure plate includes a first side surface, a second side surface and a chamfered portion, the first side surface intersects with the length direction of the cover plate, the second side surface intersects with the width direction of the cover plate, the chamfered portion is arranged between the first side surface and the second side surface, the first side surface and the second side surface are connected by the chamfered portion, the chamfered portion has a maximum dimension J1 mm along the length direction, and the chamfered portion has a maximum dimension J2 mm along the width direction, satisfying: 0.1≤J1≤50, 0.1≤J2≤50.

[0023] Accordingly, an embodiment of the present application provides a battery pack including the above-mentioned single battery.

[0024] Beneficial effect: A single battery according to an embodiment of the present application comprises: a shell having a accommodating cavity; an electrode assembly arranged in the accommodating cavity; a cover plate connected to the shell and covering the accommodating cavity, the cover plate being provided with a pole hole; a pole passing through the pole hole and electrically connected to the electrode assembly; a first insulating member being arranged on a side of the cover plate away from the electrode assembly and surrounding the pole; a pressing plate being arranged on a side of the first insulating member away from the electrode assembly and surrounding the pole; the pressing plate comprising a first body and a first step, the first body being welded to the pole to form a weld mark, the first step being connected to a side of the first body away from the electrode assembly, the minimum spacing between the weld mark and the first step being A mm, satisfying: 0.2≤A≤10; and / or the pole comprising a second body and a second step, the second body being welded to the pressing plate to form a weld mark, the second step being connected to a side of the second body away from the electrode assembly, the minimum spacing between the weld mark and the second step being B mm, satisfying: 0.2≤B≤10. By limiting the distance between the weld mark and the first and second steps, it is possible to avoid explosion spots or cold welds caused by welding close to the first and second steps, thereby ensuring the welding effect, reducing the welding defect rate, improving the tensile strength of the pole and the pressure plate, and avoiding stress during vibration and impact, which may cause the pole and the pressure plate to crack and separate, resulting in leakage, short circuit, fire and explosion, thereby improving the reliability and safety of the single battery.

[0025] 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

[0026] 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.

[0027] Figure 1 is a schematic structural diagram of a first single cell according to an embodiment of the present application;

[0028] Figure 2 is a top view of a first single cell according to an embodiment of the present application;

[0029] Figure 3 yes Figure 2 A'A' section view;

[0030] Figure 4 yes Figure 3 One of the enlarged views of part a;

[0031] Figure 5 yes Figure 3 The second enlarged view of part a;

[0032] Figure 6 yes Figure 3 Enlarged view of part b;

[0033] Figure 7 is a schematic structural diagram of a second single cell according to an embodiment of the present application;

[0034] Figure 8 is a top view of a second single cell according to an embodiment of the present application;

[0035] Figure 9 yes Figure 8 B'B' cross-sectional view;

[0036] Figure 10 yes Figure 9 Enlarged view of part c;

[0037] Figure 11 is a schematic structural diagram of a third single cell according to an embodiment of the present application;

[0038] Figure 12 is a top view of a third single cell according to an embodiment of the present application;

[0039] Figure 13 yes Figure 12 C'C' cross-sectional view;

[0040] Figure 14 yes Figure 13 Enlarged view of part d;

[0041] Figure 15 is a schematic structural diagram of a fourth single cell according to an embodiment of the present application;

[0042] Figure 16 is a top view of a fourth single cell according to an embodiment of the present application;

[0043] Figure 17 yes Figure 16 D'D' cross-sectional view;

[0044] Figure 18 yes Figure 17 One of the enlarged views of part e;

[0045] Figure 19 yes Figure 17 The second enlarged view of part e.

[0046] Figure numerals: 1, shell; 2, electrode assembly; 3, cover plate; 4, pole; 5, first insulating member; 6, pressure plate; 7, weld mark; 10, accommodating cavity; 30, pole hole; 40, second body; 41, second step; 42, first side; 43, second side; 44, positioning hole; 60, first body; 61, first step; 62, first side; 63, second side; 64, chamfered portion; 600, connecting portion; 601, limiting portion; X, thickness direction; Y, length direction; Z, width direction. DETAILED DESCRIPTION

[0047] 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.

[0048] 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.

[0049] As power battery technology matures and is widely used in electric vehicles and energy storage, the performance and safety requirements for power batteries are increasing. Batteries typically feature rivets that connect to the terminals. Connecting tabs are welded to the rivets and terminals to enable series and parallel connection of the cells. However, this process is complex, the reliability of the terminal and rivet assembly is poor, and there is a risk of poor welding.

[0050] In view of this, a single cell battery in an embodiment of the present application includes: a shell having a accommodating cavity; an electrode assembly arranged in the accommodating cavity; a cover plate connected to the shell and covering the accommodating cavity, the cover plate being provided with a pole hole; a pole passing through the pole hole and electrically connected to the electrode assembly; a first insulating member arranged on a side of the cover plate away from the electrode assembly and surrounding the pole; a pressing plate arranged on a side of the first insulating member away from the electrode assembly and surrounding the pole; the pressing plate including a first body and a first step, the first body being welded to the pole to form a weld mark, the first step being connected to a side of the first body away from the electrode assembly, and the first step being spaced apart from the pole, the minimum spacing between the weld mark and the first step being A mm, satisfying: 0.2≤A≤10; and / or the pole including a second body and a second step, the second body being welded to the pressing plate to form a weld mark, the second step being connected to a side of the second body away from the electrode assembly, and the second step being spaced apart from the pressing plate, the minimum spacing between the weld mark and the second step being B mm, satisfying: 0.2≤B≤10. By limiting the distance between the weld mark and the first and second steps, it is possible to avoid explosion spots or cold welds caused by welding close to the first and second steps, thereby ensuring the welding effect, reducing the welding defect rate, improving the tensile strength of the pole and the pressure plate, and avoiding stress during vibration and impact, which may cause the pole and the pressure plate to crack and separate, resulting in leakage, short circuit, fire and explosion, thereby improving the reliability and safety of the single battery.

[0051] The following is a detailed description of the single cell and battery pack of the present application in conjunction with the accompanying drawings. The features of the following embodiments and implementations can be combined with each other unless they conflict.

[0052] Figure 1 is a schematic structural diagram of a first single cell according to an embodiment of the present application; Figure 2 is a top view of a first single cell according to an embodiment of the present application; Figure 3 yes Figure 2 A'A' section view; Figure 4 yes Figure 3 One of the enlarged views of part a; Figure 5 yes Figure 3 The second enlarged view of part a; Figure 6 yes Figure 3 Enlarged view of part b; Figure 7 is a schematic structural diagram of a second single cell according to an embodiment of the present application; Figure 8 is a top view of a second single cell according to an embodiment of the present application; Figure 9 yes Figure 8 B'B' cross-sectional view; Figure 10 yes Figure 9 Enlarged view of part c;

[0053] Figure 11 is a schematic structural diagram of a third single cell according to an embodiment of the present application; Figure 12is a top view of a third single cell according to an embodiment of the present application; Figure 13 yes Figure 12 C'C' cross-sectional view; Figure 14 yes Figure 13 Enlarged view of part d; Figure 15 is a schematic structural diagram of a fourth single cell according to an embodiment of the present application; Figure 16 is a top view of a fourth single cell according to an embodiment of the present application; Figure 17 yes Figure 16 D'D' cross-sectional view; Figure 18 yes Figure 17 One of the enlarged views of part e; Figure 19 yes Figure 17 The second enlarged view of part e.

[0054] refer to Figures 1 to 19 The present invention provides a single battery cell, comprising a housing 1, a cover plate 3, a first insulating member 5, and a pressure plate 6. The housing 1 has a receiving cavity 10. The electrode assembly 2 is disposed within the receiving cavity 10. The cover plate 3 is connected to the housing 1 and seals the receiving cavity 10. The cover plate 3 has a terminal hole 30, through which the terminal 4 is inserted and electrically connected to the electrode assembly 2. The first insulating member 5 is arranged on the side of the cover plate 3 away from the electrode assembly 2 and surrounds the electrode 4; the pressing plate 6 is arranged on the side of the first insulating member 5 away from the electrode assembly 2 and surrounds the electrode 4; the pressing plate 6 includes a first body 60 and a first step 61, the first body 60 is welded to the electrode 4 to form a weld mark 7, the first step 61 is connected to the side of the first body 60 away from the electrode assembly 2, and the first step 61 is spaced apart from the electrode 4 along the length direction Y, and the minimum spacing between the weld mark 7 and the first step 61 is A mm, satisfying the following: 0.2≤A≤10; and / or, the electrode 4 includes a second body 40 and a second step 41, the second body 40 is welded to the pressing plate 6 to form a weld mark 7, the second step 41 is connected to the side of the second body 40 away from the electrode assembly 2, and the second step 41 is spaced apart from the pressing plate 6 along the length direction Y, and the minimum spacing between the weld mark 7 and the second step 41 is B mm, satisfying the following: 0.2≤B≤10. By limiting the distance between the weld mark 7 and the first step 61 and the second step 41, it is possible to avoid explosion spots or cold welds caused by welding close to the first step 61 and the second step 41, thereby ensuring the welding effect, reducing the welding defect rate, improving the tensile strength of the pole 4 and the pressure plate 6, and avoiding stress during vibration and impact, which may cause the pole 4 and the pressure plate 6 to crack and separate, resulting in leakage, short circuit, fire and explosion, thereby improving the reliability and safety of the single battery.

[0055] exist Figure 4In the illustrated embodiment, the pressure plate 6 includes a first body 60 and a first step 61. The first body 60 is welded to the electrode post 4 to form a weld mark 7. The first step 61 is connected to the side of the first body 60 away from the electrode assembly 2. The minimum spacing between the weld mark 7 and the first step 61 is A mm. The electrode post 4 includes a second body 40 and a second step 41. The second body 40 is welded to the pressure plate 6 to form a weld mark 7. The second step 41 is connected to the side of the second body 40 away from the electrode assembly 2. The minimum spacing between the weld mark 7 and the second step 41 is B mm, satisfying the following conditions: 0.2 ≤ A ≤ 10, 0.2 ≤ B ≤ 10. Specifically, the minimum spacing A between the weld mark 7 and the first step 61 can be any value selected from the group consisting of 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10, or a range between any two of these values. The minimum spacing B between the weld mark 7 and the second step 41 can be any value selected from the group consisting of 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10, or a range between any two values. By providing a recess between the first and second steps 61, 41, a butt weld is performed between the first and second steps 61, 41 to connect the first and second bodies 60, 40. This increases the connection strength and resistance stability between the pressure plate 6 and the terminal 4. The flushness of the pressure plate 6 and the terminal 4 increases the weldable area between the cell connector and the terminal 4. By limiting the spacing between the weld mark 7 and the first and second steps 61, 41, inconsistent welding heat transfer between the first and second steps 61, 41 is avoided, which could lead to localized overheating or insufficient temperature. This prevents hot spots or cold welds from occurring near the first and second steps 61, 41. Such a setting can ensure the welding effect, reduce the welding defect rate, improve the tensile strength of the pole 4 and the pressure plate 6, avoid stress during vibration and impact, which may cause the pole 4 and the pressure plate 6 to crack and separate, resulting in leakage, short circuit, fire and explosion, and improve the reliability and safety of the single battery.

[0056] exist Figure 10In the illustrated embodiment, the pressure plate 6 includes a first body 60 and a first step 61. The first body 60 is welded to the electrode 4 to form a weld mark 7. The first step 61 is connected to the side of the first body 60 away from the electrode assembly 2. The minimum spacing between the weld mark 7 and the first step 61 is A mm. The second step 41 is connected to the side of the second body 40 away from the electrode assembly 2. The minimum spacing between the weld mark 7 and the second step 41 is B mm, satisfying the following: 0.2 ≤ A ≤ 10. Specifically, the minimum spacing A between the weld mark 7 and the first step 61 can be any value among 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10, or a range between any two values. The first step 61 is provided to indicate the welding position between the first body 60 of the pressure plate 6 and the second body 40 of the electrode 4. The cell connector is connected to the first step 61. By butt-welding the first body 60 and the second body 40, the connection strength and resistance stability between the pressure plate 6 and the pole 4 are increased. By limiting the spacing between the weld mark 7 and the first step 61, inconsistent transfer of welding heat to the first step 61, which could lead to localized overheating or insufficient temperature, is avoided. This prevents hotspots or cold welds caused by welding near the first step 61. This arrangement ensures welding quality, reduces the defective welding rate, and improves the tensile strength of the pole 4 and pressure plate 6. It also prevents stress during vibration and impact, which could cause cracking and separation between the pole 4 and pressure plate 6, leading to leakage, short circuits, fire, and explosion, thereby improving the reliability and safety of the single battery.

[0057] exist Figure 14In the illustrated embodiment, the electrode 4 includes a second body 40 and a second step 41. The second body 40 is welded to the pressure plate 6 to form a weld mark 7. The second step 41 is connected to the side of the second body 40 facing away from the electrode assembly 2. The minimum spacing B between the weld mark 7 and the second step 41 is 0.2 mm, satisfying the following: 0.2 ≤ B ≤ 10. Specifically, the minimum spacing B between the weld mark 7 and the second step 41 can be any value among 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, or 10, or a range between any two values. The second step 41 indicates the welding position between the first body 60 of the pressure plate 6 and the second body 40 of the electrode 4. The cell connection tab is connected to the second step 41. The first body 60 and the second body 40 are connected by butt welding, thereby increasing the connection strength and resistance stability between the pressure plate 6 and the electrode 4. By limiting the distance between the weld mark 7 and the second step 41, the inconsistent transfer of welding heat on the second step 41, which could lead to local overheating or insufficient temperature, can be avoided. This can also prevent the occurrence of hot spots or cold welds when welding near the second step 41. This arrangement can ensure welding quality, reduce the welding defect rate, improve the tensile strength of the pole 4 and the pressure plate 6, and prevent the pole 4 and the pressure plate 6 from being cracked or separated due to stress during vibration and impact, resulting in leakage, short circuit, fire, and explosion, thereby improving the reliability and safety of the single battery.

[0058] In the embodiment of the present application, the first body 60 of the pressure plate 6 and the second body 40 of the terminal 4 are ultrasonically welded to form a weld mark 7. The weld mark 7 is formed at the weld location between the first body 60 and the second body 40. The minimum spacing A between the weld mark 7 and the first step 61, and the minimum spacing B between the weld mark 7 and the second step 41, can typically be measured using a vernier caliper. Welding results and vibration impact tests were performed on single cells with different dimensions A and B to test the connection strength between the pressure plate 6 and the terminal 4. The specific test results are shown in Table 1.

[0059] Table 1:

[0060]

[0061]

[0062] In some embodiments, an unqualified welding result refers to the generation of weld cracks or cold welds. The vibration and shock test can be performed on the battery pack using the test method in GB38031-2020. The vibration and shock test results can be used to determine whether the tensile strength at weld mark 7 meets the requirements.

[0063] With reference to Comparative Examples 1-1 and 1-2, the minimum spacing A between the weld mark 7 and the first step 61, and the minimum spacing B between the weld mark 7 and the second step 41 are both less than 0.2 mm, resulting in an unqualified welding result, that is, the welding produces a welding explosion point or a cold weld, which affects the welding effect, and the vibration impact test result is unsatisfactory. It is understandable that when the welding effect is not good, the tensile strength at the weld mark 7 is insufficient, which makes the risk of weld cracking or falling off during the vibration impact test. With reference to Comparative Examples 1-3 to 1-5, the minimum spacing A between the weld mark 7 and the first step 61, and the minimum spacing B between the weld mark 7 and the second step 41 are both greater than 10 mm. Excessive clearance will lead to a reduction in the weldable area between the battery cell connector and the pole 4, and there is a risk of deformation, cracking, or even falling off of the battery cell connector during the vibration impact test. With reference to Examples 1-3 to 1-7, the minimum spacing A between the weld mark 7 and the first step 61, and the minimum spacing B between the weld mark 7 and the second step 41 satisfy the following conditions: 0.2≤A≤10, 0.2≤B≤10. The test results show that the single cells of Examples 1-1 to 1-5 are all found to be welded as qualified, and the vibration impact test meets the requirements. By limiting the spacing between the weld mark 7 and the first step 61 and the second step 41, it is possible to avoid welding close to the first step 61 and the second step 41 to produce explosion points or cold welds, thereby ensuring the welding effect, reducing the welding defect rate, and improving the tensile strength of the pole 4 and the pressure plate 6. This avoids stress during the vibration impact process, which may cause the pole 4 and the pressure plate 6 to crack and separate, leading to leakage, short circuit, fire, and explosion, thereby improving the reliability and safety of the single cell.

[0064] exist Figure 4 and Figure 18 In the illustrated embodiment, the maximum dimension F of the first step 61 along the thickness direction X of the cover plate 3 is F mm, satisfying the following: 0.5 ≤ F ≤ 10. Specifically, the maximum dimension F of the first step 61 along the thickness direction X of the cover plate 3 can be any value selected from the group consisting of 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10, or a range between any two values. A too small maximum dimension F of the first step 61 along the thickness direction X of the cover plate 3 increases the risk of poor welding, potentially leading to weld cracks or cold welds. A too large maximum dimension F of the first step 61 along the thickness direction X of the cover plate 3 may oversize the pressure plate 6, increase the weight of the battery cells, and thus reduce the energy density of the battery cells. By limiting the maximum dimension F of the first step 61 along the thickness direction X of the cover plate 3, the present application allows the pressure plate 6 and the pole 4 to be flush, thereby increasing the weldable area between the cell connection piece and the pole 4, thereby helping to improve welding quality and connection stability. Furthermore, the connection strength and stability between the pole 4 and the pressure plate 6 can be effectively improved.

[0065] exist Figure 4 and Figure 18 In the illustrated embodiment, the minimum spacing G between the first step 61 and the second step 41 is G mm, satisfying the following: 0.5 ≤ G ≤ 10. Specifically, the minimum spacing G between the first step 61 and the second step 41 can be any value selected from the group consisting of 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10, or a range between any two values. If the minimum spacing G between the first step 61 and the second step 41 is too small, the weldable area of the weld mark 7 will be too small, resulting in the weld mark 7 being too small in size, thus affecting the welding effect. If the minimum spacing G between the first step 61 and the second step 41 is too large, the weldable area on the pressure plate 6 and the electrode 4 will be reduced, thus affecting the connection strength between the electrode assembly 2 and the electrode 4, as well as the connection strength between the cell connector and the electrode 4.

[0066] exist Figure 19 In the illustrated embodiment, the first body 60 includes a connecting portion 600 and a stopper 601, the first step 61 being connected to the connecting portion 600. The stopper 601 is disposed on a side of the second body 40 away from the electrode assembly 2. The stopper 601 is welded to the second body 40 to form a weld mark 7. The stopper 601 of the first body 60 is connected to the second body 40 by penetrating welding, thereby increasing the connection strength and resistance stability between the pressure plate 6 and the electrode post 4.

[0067] In some embodiments, the pole 4 includes a first surface 42 and a second surface 43 that are arranged opposite to each other in the thickness direction X of the cover plate 3. The first surface 42 is the surface of the pole 4 that is farthest from the electrode assembly 2 in the thickness direction X, and the second surface 43 is the surface of the pole 4 that is closest to the electrode assembly 2 in the thickness direction X. The area of the first surface 42 is S1 mm. 2 , the area of the second surface 43 is S2mm 2 , satisfying: 0.01≤S1 / S2≤20. Specifically, the ratio of the area S1 of the first surface 42 to the area S2 of the second surface 43 can be any one of 0.01, 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or a range between any two values. The first surface 42 is connected to the cell connecting piece, and the second surface 43 is connected to the electrode assembly 2. By limiting the ratio of the area S1 of the first surface 42 to the area S2 of the second surface 43, the risk of unreliable connection caused by too small weldable area of the first surface 42 and the second surface 43 of the pole 4 can be avoided, and the connection stability between the electrode assembly 2 and the pole 4, as well as the connection stability between the cell connecting piece and the pole 4 can be ensured.

[0068] In an embodiment of the present application, vibration impact tests are performed on single cells with different ratios of S1 / S2 to detect the connection strength between the electrode assembly 2 and the pole 4 and the connection strength between the cell connecting piece and the pole 4. The specific test results are shown in Table 2.

[0069] The minimum distance A between the welding mark 7 and the first step 61 and the minimum distance B between the welding mark 7 and the second step 41 satisfy the following conditions: 0.2≤A≤10, 0.2≤B≤10.

[0070] Table 2:

[0071]

[0072] The vibration and shock test can be performed on the battery pack using the test method in GB38031 2020. The vibration and shock test results can be used to determine whether the connection strength between the electrode assembly 2 and the terminal 4, and the connection strength between the cell connector and the terminal 4 meet the requirements.

[0073] Referring to Comparative Example 2-1, the area S2 of the second surface 43 is 2000 mm 2 , the area S1 of the first surface 42 is 10 mm 2 , it can be seen from the vibration shock test results that when the ratio S1 / S2 of the area S1 of the first surface 42 and the area S2 of the second surface 43 is less than 0.01, the vibration shock test does not meet the requirements. It can be understood that if the area of the first surface 42 is too small, the weldable area between the first surface 42 and the battery cell connecting piece will be insufficient, the track length of the weld mark 7 will be insufficient, the tensile strength of the pole 4 and the battery cell connecting piece will be insufficient, and there will be a risk of cracking or falling off between the battery cell connecting piece and the pole 4 during the vibration shock test. Referring to Comparative Examples 2-2 and 2-3, it can be seen from the vibration shock test results that when the ratio S1 / S2 of the area S1 of the first surface 42 and the area S2 of the second surface 43 are both greater than 20, the vibration shock test does not meet the requirements. If the area of the first surface 42 is too small, the weldable area connecting the second surface 43 and the electrode assembly 2 will be insufficient, resulting in insufficient tensile strength between the pole 4 and the electrode assembly 2, and there may be a risk of cracking or falling off between the pole 4 and the electrode assembly 2 during the vibration shock test. With reference to Examples 2-1 to 2-8, it can be seen from the vibration impact test results that when the ratio S1 / S2 of the area S1 of the first surface 42 to the area S2 of the second surface 43 satisfies 0.01≤S1 / S2≤20, the risk of unreliable connection caused by the weldable area of the first surface 42 and the second surface 43 of the pole 4 being too small can be avoided, and the connection stability between the electrode assembly 2 and the pole 4, as well as the connection stability between the battery cell connecting piece and the pole 4 can be ensured.

[0074] In some embodiments, the penetration depth of the welding between the pressure plate 6 and the pole 4 is C mm, and the maximum dimension of the pole 4 along the thickness direction X of the cover plate 3 is D mm, satisfying the following: 0.005≤C / D≤0.89. Specifically, the ratio between the penetration depth C of the welding between the pressure plate 6 and the pole 4 and the maximum dimension D of the pole 4 along the thickness direction X of the cover plate 3 can be any one of 0.005, 0.01, 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, 0.89, or a range between any two of these values. Figure 5 、 Figure 10 and Figure 14 In the embodiment shown, the first body 60 and the second body 40 are connected by butt welding, and the penetration of the pressure plate 6 and the electrode 4 is the distance from the upper surface of the first body 60 and the second body 40 to the side of the weld mark 7 facing the electrode assembly 2. Figure 19 In the described embodiment, the first body 60 and the second body 40 are connected by penetration welding. The penetration depth of the weld between the pressure plate 6 and the electrode 4 is the distance from the upper surface of the second body 40 to the side of the weld facing the electrode assembly 2, excluding the thickness of the stopper 601. By limiting the ratio between the penetration depth C of the weld between the pressure plate 6 and the electrode 4 and the maximum dimension D of the electrode 4 along the thickness direction X of the cover plate 3, the present application can ensure sufficient penetration during the welding process, avoid excessively shallow or deep penetration, and ensure the stability of the connection between the pressure plate 6 and the electrode 4.

[0075] In some embodiments, the single battery further satisfies: 0.1≤C≤5. Specifically, the penetration C of the welding between the pressure plate 6 and the terminal 4 can be any value among 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, or a range between any two values.

[0076] In some embodiments, the single battery further satisfies: 1.5≤D≤20. Specifically, the maximum dimension D of the pole 4 along the thickness direction X of the cover plate 3 can be any value among 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or a range between any two values.

[0077] In the embodiment of the present application, vibration shock tests are performed on single cells with different C / D ratios to detect the connection strength between the pressure plate 6 and the terminal 4. The specific test results are shown in Table 3.

[0078] The minimum distance A between the welding mark 7 and the first step 61 and the minimum distance B between the welding mark 7 and the second step 41 satisfy the following conditions: 0.2≤A≤10, 0.2≤B≤10.

[0079] Table 3:

[0080] C(mm) D(mm) C / D Vibration shock test results Example 3-1 0.1 20 0.005 satisfy Example 3-2 0.2 2.5 0.08 satisfy Example 3-3 0.5 2.5 0.2 satisfy Examples 3-4 0.7 2 0.35 satisfy Examples 3-5 1.1 2 0.55 satisfy Examples 3-6 2 3 0.66 satisfy Examples 3-7 1.5 2 0.75 satisfy Examples 3-8 2.5 3 0.83 satisfy Examples 3-9 2.5 2.8 0.89 satisfy Comparative Example 3-1 0.1 25 0.004 Dissatisfied Comparative Example 3-2 3 3 1 Dissatisfied

[0081] The vibration and shock test can be performed on the battery pack using the test method in GB38031 2020. The vibration and shock test results can be used to determine whether the connection strength between the pressure plate 6 and the terminal 4 meets the requirements.

[0082] Referring to Comparative Example 3-1, the vibration and shock test results show that when the ratio between the weld penetration C of the pressure plate 6 and the pole 4 and the maximum dimension D of the pole 4 along the thickness direction X of the cover plate 3 is less than 0.005, the vibration and shock test fails to meet the requirements. It is understandable that as the weld penetration C of the pressure plate 6 and the pole 4 decreases, the connection stability between the pressure plate 6 and the pole 4 decreases, and there is a risk of cracking or detaching the weld mark 7 between the pressure plate 6 and the pole 4 during the vibration and shock test. Referring to Comparative Example 3-2, the vibration and shock test results show that when the ratio between the weld penetration C of the pressure plate 6 and the pole 4 and the maximum dimension D of the pole 4 along the thickness direction X of the cover plate 3 is greater than 0.89, the vibration and shock test fails to meet the requirements. It is understandable that when the weld penetration C of the pressure plate 6 and the pole 4 is greater, the stress distribution at the weld mark 7 may become more concentrated, resulting in a decrease in the connection strength between the pressure plate 6 and the pole 4. Furthermore, when the C / D ratio is equal to 1, that is, welding penetrates, resulting in a crack or slag at the bottom of the terminal 4, which may pose a risk of insulation or sealing failure, affecting the safety and reliability of the single battery. Referring to Examples 3-1 to 3-9, the vibration and shock test results show that when the ratio between the penetration C of the weld between the pressure plate 6 and the terminal 4 and the maximum dimension D of the terminal 4 along the thickness direction X of the cover plate 3 satisfies 0.005≤C / D≤0.89, sufficient penetration can be ensured during the welding process, while avoiding excessive or shallow penetration, ensuring a stable connection between the pressure plate 6 and the terminal 4.

[0083] In some embodiments, the weld width E of the pressure plate 6 and the pole 4 is E mm, which satisfies the following conditions: 0.1≤E≤5. Specifically, the weld width E of the pressure plate 6 and the pole 4 can be any one of 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0 or a range between any two values. Figure 5 、 Figure 10 and Figure 14 In the embodiment shown, the first body 60 and the second body 40 are connected by butt welding, and the weld width E of the pressure plate 6 and the pole 4 is the size of the weld mark 7 on the upper surface of the first body 60 and the second body 40. Figure 19In the embodiment described, the first body 60 and the second body 40 are connected by penetration welding, and the weld width E of the pressure plate 6 and the pole 4 is the size of the weld mark 7 on the upper surface of the second body 40, rather than the size of the weld mark 7 on the upper surface of the limiting portion 601.

[0084] In some embodiments, the smaller the weld width E between the pressure plate 6 and the pole 4, the weaker the connection strength between the pressure plate 6 and the pole 4, and the lower the tensile strength. If the weld width E between the pressure plate 6 and the pole 4 is too large, the spacing between the weld mark 7 and the first step 61 or the second step 41 is too small, which can easily cause a hotspot or a cold weld, increasing the welding defect rate. By limiting the weld width E between the pressure plate 6 and the pole 4, the tensile strength of the pole 4 and the pressure plate 6 can be effectively improved, preventing stress during vibration and impact, which could cause the pole 4 and the pressure plate 6 to crack and separate, leading to leakage, short circuit, fire, and explosion, thereby improving the reliability and safety of the single battery.

[0085] exist Figure 6 In the illustrated embodiment, the electrode 4 has a locating hole 44 at its center, located on the side of the electrode 4 facing away from the electrode assembly 2. The maximum dimension of the locating hole 44 along the length direction Y of the cover plate 3 is H mm, and the maximum dimension of the locating hole 44 along the thickness direction X of the cover plate 3 is 1 mm. The length direction Y intersects the thickness direction X, satisfying the following conditions: 0.5 ≤ H ≤ 10, and 0.1 ≤ I ≤ 10. The locating hole 44 is used to confirm the trajectory when welding the electrode 4 and the pressure plate 6. Specifically, the maximum dimension H of the locating hole 44 along the length direction Y of the cover plate 3 can be any value selected from the group consisting of 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10, or a range between any two of these values. The maximum dimension I of the positioning hole 44 along the thickness direction X of the cover plate 3 can be any value selected from the group consisting of 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, and 10, or a range between any two values. It is understood that the positioning hole 44 can be circular, conical, square, rectangular, circular, or a combination of these shapes, and can be formed by die stamping or machining. If the positioning hole 44 is too small, burrs may be generated, affecting identification and causing insulation failure between the pole 4 and the housing 1. If the positioning hole 44 is too large, the weldable area of the pole 4 may be reduced. By limiting the maximum dimension H of the positioning hole 44 along the length direction Y of the cover plate 3 and the maximum dimension I of the positioning hole 44 along the thickness direction X of the cover plate 3, better identification can be achieved, allowing for precise positioning of the weld mark 7. Positioning holes 44 of different sizes and shapes can be designed based on the size of the pole 4 to ensure accurate positioning.

[0086] In other embodiments, the positioning hole 44 may be circular, conical, square, rectangular, circular, or a combination thereof, and may be formed by spraying, labeling, drawing, or laser engraving. This arrangement prevents burrs from forming on the positioning hole 44 and prevents the weldable area of the electrode 4 from being affected, thereby ensuring the quality and reliability of subsequent welding between the cell connector and the electrode 4.

[0087] In some embodiments, the track formed by the weld marks 7 can be continuous. This arrangement can ensure the connection strength between the pole 4 and the pressure plate 6. In other embodiments, the track formed by the weld marks 7 can be intermittent. While ensuring the connection strength between the pole 4 and the pressure plate 6, segmented welding can be used to reduce the welding track length and welding time, reduce energy consumption, and lower costs.

[0088] In some embodiments, the track formed by the weld mark 7 can be circular, rectangular, elliptical, prismatic, or a combination thereof. The shape of the track of the weld mark 7 can be consistent with the cross-sectional shape of the pole 4 to improve the space utilization of the welding area on the pole 4.

[0089] In some embodiments, the pressing plate 6 includes a first side surface 62, a second side surface 63 and a chamfered portion 64. The first side surface 62 intersects with the length direction Y of the cover plate 3, and the second side surface 63 intersects with the width direction Z of the cover plate 3. The chamfered portion 64 is provided between the first side surface 62 and the second side surface 63. The first side surface 62 and the second side surface 63 are connected by the chamfered portion 64. The chamfered portion 64 has a maximum dimension J1 mm along the length direction Y and the width direction Z, and has a maximum dimension J2 mm along the width direction Z, satisfying the following: 0.1≤J1≤50, 0.1≤J2≤50. Figure 2 In the illustrated embodiment, the maximum dimension J1 of the chamfered portion 64 along the length direction Y can be any value selected from the group consisting of 0.1, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50, or a range between any two values. The maximum dimension J2 of the chamfered portion 64 along the width direction Z can be any value selected from the group consisting of 0.1, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50, or a range between any two values. The maximum dimension J1 of the chamfered portion 64 along the length direction Y and the maximum dimension J2 of the chamfered portion 64 along the width direction Z can be the same or different, and this is not a limitation of the present application.

[0090] When the maximum dimension J1 of the chamfered portion 64 along the length direction Y or the maximum dimension J2 of the chamfered portion 64 along the width direction Z is too small, the transition positions around the pressure plate 6 will become stress concentration points, and there is a risk of cracking or even breaking during vibration impact. When the maximum dimension J1 of the chamfered portion 64 along the length direction Y or the maximum dimension J2 of the chamfered portion 64 along the width direction Z is too large, it will affect the weldable area of the pressure plate 6, resulting in reduced strength and connection stability of the pressure plate 6. This application helps maintain the strength and stability of the pressure plate 6 and reduce stress concentration by limiting the maximum dimension J1 of the chamfered portion 64 along the length direction Y and the maximum dimension J2 of the chamfered portion 64 along the width direction Z, thereby reducing stress concentration, thereby reducing the risk of cracking or falling off of the pressure plate 6 under vibration impact and improving the safety and stability of the single battery.

[0091] Accordingly, an embodiment of the present application further provides a battery pack comprising the above-described single cell. The battery pack comprises a housing 1, an electrode assembly 2, a cover plate 3, a first insulating member 5, and a pressure plate 6. The pressure plate 6 is disposed on the side of the first insulating member 5 away from the electrode assembly 2 and surrounds the electrode post 4. The pressure plate 6 comprises a first body 60 and a first step 61. The first body 60 is welded to the electrode post 4 to form a weld mark 7. The first step 61 is connected to the side of the first body 60 away from the electrode assembly 2. The minimum spacing between the weld mark 7 and the first step 61 is A mm, satisfying the following: 0.2 ≤ A ≤ 10. The electrode post 4 comprises a second body 40 and a second step 41. The second body 40 is welded to the pressure plate 6 to form a weld mark 7. The second step 41 is connected to the side of the second body 40 away from the electrode assembly 2. The minimum spacing between the weld mark 7 and the second step 41 is B mm, satisfying the following: 0.2 ≤ B ≤ 10. By limiting the distance between the weld mark 7 and the first step 61 and the second step 41, it is possible to avoid welding hot spots or cold welds, thereby ensuring the welding effect, reducing the welding defect rate, increasing the tensile strength of the pole 4 and the pressure plate 6, and improving the safety of the single battery.

[0092] Accordingly, embodiments of the present application further provide an electrical device, which may be a mobile phone, portable device, laptop computer, electric vehicle, electric car, ship, spacecraft, electric toy, and electric tool. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft; electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys; and electric tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0093] 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.

[0094] 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: include: A housing having a receiving cavity; an electrode assembly, disposed in the accommodating cavity; a cover plate connected to the shell and covering the accommodating cavity, wherein the cover plate is provided with a pole hole; A pole, passing through the pole hole and electrically connected to the electrode assembly; a first insulating member, disposed on a side of the cover plate away from the electrode assembly and surrounding the electrode column; a pressure plate, disposed on a side of the first insulating member away from the electrode assembly and surrounding the electrode column; The pressure plate includes a first body and a first step, the first body is welded to the pole to form a weld mark, the first step is connected to the side of the first body away from the electrode assembly, and the first step is spaced apart from the pole, the minimum spacing between the weld mark and the first step is A mm, and the following conditions are satisfied: 0.2≤A≤10; and / or, the pole includes a second body and a second step, the second body is welded to the pressure plate to form a weld mark, the second step is connected to the side of the second body away from the electrode assembly, and the second step is spaced apart from the pressure plate, the minimum spacing between the weld mark and the second step is B mm, and the following conditions are satisfied: 0.2≤B≤10.

2. The single cell according to claim 1, characterized in that: The first body includes a connecting portion and a limiting portion connected to each other, the first step is connected to the connecting portion, the limiting portion is arranged on a side of the second body away from the electrode assembly, and the limiting portion and the second body are welded to form the weld mark.

3. The single cell according to claim 1, characterized in that: The pole includes a first surface and a second surface that are arranged opposite to each other in the thickness direction of the cover plate, the first surface is the surface of the pole farthest from the electrode assembly in the thickness direction, and the second surface is the surface of the pole closest to the electrode assembly in the thickness direction. The area of the first surface is S1 mm 2 , the area of the second surface is S2 mm 2 , satisfying: 0.01≤S1 / S2≤20.

4. The single cell according to claim 1, characterized in that: The welding depth between the pressure plate and the pole is C mm, the maximum dimension of the pole along the thickness direction of the cover plate is D mm, and the following conditions are satisfied: 0.005≤C / D≤0.

89.

5. The single cell according to claim 4, characterized in that: The single battery further satisfies: 0.1≤C≤5, and / or, 1.5≤D≤20.

6. The single cell according to claim 1, characterized in that: The weld width between the pressure plate and the pole is E mm, and satisfies: 0.1≤E≤5.

7. The single cell according to claim 1, characterized in that: The maximum dimension of the first step along the thickness direction of the cover plate is F mm, satisfying: 0.5≤F≤10; and / or The minimum distance between the first step and the second step is G mm, which satisfies the following: 0.5≤G≤10.

8. The single cell according to claim 1, characterized in that: A positioning hole is provided at the center of the pole, and the positioning hole is arranged on a side of the pole away from the electrode assembly; The maximum dimension of the positioning hole along the length direction of the cover plate is H mm, and the maximum dimension of the positioning hole along the thickness direction of the cover plate is 1 mm. The length direction intersects with the thickness direction and satisfies: 0.5≤H≤10, 0.1≤I≤10.

9. The single cell according to claim 1, characterized in that: The pressing plate includes a first side surface, a second side surface and a chamfered portion, the first side surface intersects with the length direction of the cover plate, the second side surface intersects with the width direction of the cover plate, the chamfered portion is arranged between the first side surface and the second side surface, the first side surface and the second side surface are connected by the chamfered portion, the chamfered portion has a maximum dimension J1 mm along the length direction, and the chamfered portion has a maximum dimension J2 mm along the width direction, satisfying the following: 0.1≤J1≤50, 0.1≤J2≤50.

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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