Battery and battery pack

Abstract

The invention relates to the technical field of batteries, and discloses a battery and a battery pack, the battery comprises a shell, a pole and a battery cell; the shell is provided with an accommodating cavity and a through hole; the battery cell comprises a battery cell main body and a lead-out part, the battery cell main body is arranged in the accommodating cavity, and the battery cell main body comprises a plurality of stacked pole pieces and diaphragms positioned between two adjacent pole pieces; the leading-out part is provided with a first end and a second end which are opposite; the leading-out part is arranged on one side, facing the through hole, of the battery cell main body, the leading-out part is provided with a first end and a second end which are opposite, the first end is connected to the pole piece, at least part of the leading-out part is located in the through hole, and the leading-out part and the pole column are welded to form a first welding mark; wherein the minimum distance between the diaphragm and the through hole is h1, the minimum distance between the pole piece and the through hole is h2, the minimum distance between the first welding print and the first end is L1, H = h2-h1, and L1 / H is larger than or equal to 2 and smaller than or equal to 30; the battery provided by the invention can reduce the possibility of internal short circuit, improve the safety and prolong the service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a battery and a battery pack. BACKGROUND

[0002] In the technical field of batteries, improving the utilization rate of the internal space of the battery is of great significance to improve the energy density and overall performance of the battery; at present, in order to achieve this goal, some technical solutions set part of the cell lead-out part in the shell through hole, thereby shortening the flow path between the pole and the cell lead-out part, thereby reducing the internal resistance of the battery and improving the charge and discharge efficiency; however, this setting has obvious defects in actual application. In the battery assembly process, the cell lead-out part is limited by space and is bent too much, which will cause the structure stability of the cell internal pole and the cell lead-out part to be poor, and there is a risk of short circuit, which affects the safety and service life of the battery. SUMMARY

[0003] To at least solve one of the technical problems existing in the prior art, the present application aims to provide a battery and a battery pack with the battery, which can reduce the possibility of internal short circuit and improve safety and service life.

[0004] In order to achieve the above-mentioned purpose, the present application provides a battery, which has a first direction, a second direction and a third direction perpendicular to each other, and the battery comprises a shell, a pole and a cell; the shell has a receiving cavity, the shell has a first side wall in the first direction of the receiving cavity, and the first side wall is provided with a through hole; the pole is arranged on the side of the through hole away from the cell; the cell comprises a cell body and a lead-out part, the cell body is arranged in the receiving cavity, and the cell body comprises a plurality of pole pieces arranged in a stack and a separator between adjacent two pole pieces; the lead-out part has opposite first and second ends; the lead-out part is arranged on the side of the cell body facing the through hole, and the lead-out part has opposite first and second ends, and the first end is connected to the pole piece; wherein, along the first direction, the minimum distance between the separator and the through hole is h1, the minimum distance between the pole piece and the shell is h2, and the minimum distance between the first welding mark and the first end is L1, H = h2-h1, and 2≤L1 / H≤30 is satisfied.

[0005] Compared with the prior art, the battery provided by the embodiment of the present application has the beneficial effects that: by limiting 2≤L1 / H≤30, the extension length of the lead-out part in the battery is controlled within a reasonable range, so that the lead-out part cannot be too close to the polar plate with opposite polarity, thereby avoiding the lead-out part from being overlapped with the polar plate with opposite polarity, reducing the possibility of internal short circuit of the battery and improving the safety of the battery; and the mechanical damage or fracture of the lead-out part caused by excessive bending can be avoided, the structural strength and connection reliability of the lead-out part are improved, and thus the stability and service life of the battery are improved. BRIEF DESCRIPTION OF DRAWINGS

[0006] Figure 1 is a structural schematic diagram of a battery provided by the first embodiment of the present application;

[0007] Figure 2 is a front view of a battery provided by the first embodiment of the present application;

[0008] Figure 3 is an enlarged schematic diagram of A of Figure 2

[0009] Figure 4 is a side view of a battery provided by the first embodiment of the present application;

[0010] Figure 5 is an enlarged schematic diagram of B of Figure 4

[0011] Figure 6 is an enlarged schematic diagram of E of Figure 5

[0012] Figure 7 is a first size schematic diagram of the cell body, the lead-out part and the first welding mark provided by the first embodiment of the present application;

[0013] Figure 8 is a side view of a tab provided by the first embodiment of the present application;

[0014] Figure 9 is a schematic diagram of a flattened tab provided by the first embodiment of the present application;

[0015] Figure 10 is a relationship schematic diagram of a shell, a pole and an insulating part provided by the first embodiment of the present application;

[0016] Figure 11 is a partial sectional view of a shell provided by the first embodiment of the present application;

[0017] Figure 12 is a relationship schematic diagram of a shell, a tab and a pole provided by the second embodiment of the present application;

[0018] Figure 13 ​​​is a schematic view of the flattened tab provided by the second embodiment of the present application;

[0019] Figure 14 is a schematic view of the relationship between the second welding mark and the first welding mark provided by the third embodiment of the present application

[0020] Figure 15 is a schematic view of the flattened tab provided by the third embodiment of the present application;

[0021] Figure 16 is a schematic view of the relationship between the fuse and the tab provided by the fourth embodiment of the present application;

[0022] Figure 17 is a schematic view of the relationship between the tab and the main body of the battery cell provided by the fifth embodiment of the present application;

[0023] Figure 18 is a schematic view of the relationship between the insulating glue and the battery cell provided by the sixth embodiment of the present application;

[0024] Figure 19 is a schematic view of the relationship between the tab and the adapter provided by the seventh embodiment of the present application; Figure 18 is a schematic view of the relationship between the tab and the adapter provided by the eighth embodiment of the present application;

[0025] Figure 20 is a schematic view of the relationship between the tab and the adapter provided by the ninth embodiment of the present application;

[0026] Figure 21 is a schematic view of the relationship between the tab and the adapter provided by the ninth embodiment of the present application;

[0027] Figure 22 is a schematic view of the relationship between the tab and the adapter provided by the ninth embodiment of the present application;

[0028] Figure 23 is a schematic view of the flattened tab provided by the ninth embodiment of the present application;

[0029] Figure 24 is a schematic view of the relationship between the shell and the tab provided by the tenth embodiment of the present application;

[0030] Figure 25 is a partial sectional view of the shell provided by the tenth embodiment of the present application;

[0031] Figure 26 is a sectional view of a battery pack provided by the eleventh embodiment of the present application;

[0032] Figure 27 is a schematic view of the relationship between the tab and the adapter provided by the eleventh embodiment of the present application; Figure 26 is a schematic view of the relationship between the tab and the adapter provided by the eleventh embodiment of the present application;

[0033] In the figure, 1, shell; 1A, shell body; 1B, cover plate; 10, accommodating cavity; 11, through hole; 111, first groove; 112, second groove;

[0034] 2, tab;

[0035] 3. cell; 31, cell body; 32, lead-out portion; 311, tab; 312, separator; 321, tab; 322, adapter piece; 3211, first connecting portion; 3212, welding portion; 3213, extension portion; 3214, first bending portion; 3215, second bending portion; 3201, tab piece; 32141, first open slot; 32151, second open slot;

[0036] 4. insulating member;

[0037] 5. reinforcing rib;

[0038] 6. fuse;

[0039] 7. insulating glue;

[0040] 8. insulating tape; 81, first portion; 82, second portion; 83, third portion;

[0041] 9. press ring;

[0042] 101, first welding mark; 102, second welding mark; 103, third welding mark;

[0043] 201, first end; 202, second end; 205, first insulating end; 206, first orifice end; 207, fifth end; 208, sixth end;

[0044] 301, first surface; 302, second surface; 303, third surface; 304, fourth surface; 305, fifth surface; 306, sixth surface;

[0045] 400, first auxiliary plane; 401, first orthographic projection; 402, second orthographic projection;

[0046] 501, first mark point; 502, second mark point;

[0047] 1000, conductive row;

[0048] Z, first direction; Y, second direction; X, third direction; Q, extension direction of flattened tab. DETAILED DESCRIPTION

[0049] The specific embodiments of the present application will be further described in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present application, but are not intended to limit the scope of the present application.

[0050] In the description of the present application, it is to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0051] The terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0052] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0053] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include the direct contact of the first and second features, or can include the contact of the first and second features through another feature between them. Moreover, the "upper", "above" and "above" of the first feature to the second feature includes the vertical direction of the first feature above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature to the second feature includes the vertical direction of the first feature below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0054] Unless otherwise defined, all technical and scientific terms used in the present application have the same meaning as understood by a person skilled in the art to which the present application belongs; the terms used in the specification of the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the present application; the terms "include" and "have" in the specification and claims of the present application and the above description of the drawings are intended to cover non-exclusive inclusion.

[0055] In this invention, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments.

[0056] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0057] Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0058] Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] Example 1

[0060] like Figures 1 to 11 As shown, a battery provided in Embodiment 1 of the present invention has two perpendicular directions: a first direction Z, a second direction Y, and a third direction X. The battery includes a casing 1, terminals 2, and a cell 3. The casing 1 has a receiving cavity 10. The first sidewall 11 of the casing 1 in the first direction Z has a through hole 12 communicating with the receiving cavity 10. The terminals 2 are located on the side of the through hole 12 away from the cell 3. The cell 3 includes a cell body 31 and a lead-out portion 32. The cell body 31 is disposed in the receiving cavity 10. The cell body 31 includes a plurality of stacked electrode plates 311 and a separator 312 located between two adjacent electrode plates 311. The lead-out portion 32 is disposed on the side of the cell body 31 facing the through hole 12. The lead-out portion 32 has a first end 201 and a second end 202 opposite to each other. The first end 201 is connected to the electrode plate 311. At least a portion of the lead-out portion 32 is located in the through hole 12. The lead-out portion 32 and the terminals 2 are welded to form a first solder mark 101.

[0061] Along the first direction Z, the minimum distance between the diaphragm 312 and the through hole 12 is h1, the minimum distance between the electrode 311 and the through hole 12 is h2, and the minimum distance between the first solder mark 101 and the first end is L1. H = h2 - h1, satisfying: 2 ≤ L1 / H ≤ 30.

[0062] It should be noted that since H = h2 - h1, and h2 and h1 are the minimum distance between the diaphragm 312 and the through hole 12 and the minimum distance between the electrode 311 and the through hole 12, respectively, H refers to the size of the area of ​​the diaphragm 312 that extends beyond the electrode 311.

[0063] Based on this technical solution, in this invention, the larger the value of L1 / H (which can be either a larger L1 or a smaller H), the larger the minimum distance L1 between the first solder mark 101 and the first end 201, relative to the distance H of the area where the separator 312 extends beyond the electrode 311. That is, the longer the extension length of the lead-out portion 32 inside the battery, the greater the value of L1 / H determines the extension length of the lead-out portion 32 inside the battery. If the extension length of the lead-out portion 32 inside the battery is too long, the lead-out portion 32 will be too close to the electrode 311 in the cell body 31 with the opposite polarity to the lead-out portion 32, causing the lead-out portion 32 to easily overlap with the electrode 311 with the opposite polarity, resulting in a short circuit in the battery and affecting the safety and normal use of the battery. If the extension length of the lead-out portion 32 inside the battery is too short, the lead-out portion 32 will be too close to the electrode 311 in the cell body 31 with the opposite polarity, resulting in a short circuit in the battery and affecting the safety and normal use of the battery. During assembly, excessive bending can cause significant stress, making the lead-out portion 32 prone to tearing. Once torn, the lead-out portion 32 interrupts the current transmission path within the battery, leading to battery failure and inability to function properly. This invention controls the extension length of the lead-out portion 32 within the battery to a reasonable range by limiting 2≤L1 / H≤30. This prevents the lead-out portion 32 from getting too close to the opposite polarity electrode 311, avoiding overlap and reducing the possibility of internal short circuits, thus improving battery safety. Furthermore, it prevents mechanical damage or breakage caused by excessive bending, enhancing the structural strength and connection reliability of the lead-out portion 32, thereby improving battery stability and lifespan.

[0064] By limiting 2≤L1 / H≤30 and placing at least a portion of the lead-out portion 32 within the through hole 12, the lead-out portion 32 can be accommodated within the through hole 12 of the housing 1 while ensuring the structural stability of the lead-out portion 32. This shortens the current path, helps reduce the battery's internal resistance, and improves charging and discharging efficiency and overall energy density.

[0065] Preferably, 1mm ≤ H ≤ 7mm.

[0066] H can be any value satisfying 1mm≤H≤7mm, such as 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5mm, 5.2mm, 5.4mm, 5.6mm, 5.8mm, 6mm, 6.2mm, 6.4mm, 6.6mm, 6.8mm, 7mm, etc.

[0067] Preferably, 7mm≤L1≤39mm.

[0068] L1 can be any value satisfying 7mm≤L1≤39mm, such as 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, etc.

[0069] It should be noted that "H" refers to the minimum distance between the edge of the pole piece located at the outermost side of the battery cell and the edge of the adjacent diaphragm in the first direction Z, specifically: taking the end of the battery cell closest to the through hole in the first direction Z as the reference area; taking the end face of the outermost pole piece at this position (i.e. the farthest extension point in the first direction Z) as the starting point; measuring the shortest distance to the end face of the adjacent diaphragm perpendicular to the first direction Z; this distance is H, which represents the relative position difference between the edge of the pole piece and the edge of the diaphragm in the direction close to the through hole.

[0070] In the existing mainstream battery, the outermost pole piece close to the through hole side is usually a negative pole piece. Therefore, in most embodiments, H is actually the Z-direction distance between the end face of the negative pole piece and the end face of the adjacent diaphragm.

[0071] The specific measurement method of H is as follows:

[0072] Sample preparation: Keep the battery cell assembly in the original stacked state without disassembling or separating the pole piece and the diaphragm;

[0073] Determine the first direction Z: define the direction perpendicular to the stacking direction of the battery cell as the first direction Z, i.e. the direction of the main body of the battery cell towards the through hole;

[0074] Identify the edge of the diaphragm and the edge of the pole piece: identify the position of the edge of the diaphragm and the edge of the pole piece in the stacked structure of the battery cell by visual observation, microscopic imaging or X-ray detection, etc.

[0075] Determine the diaphragm overhanging area: identify the part of the diaphragm extending outward relative to the pole piece in the first direction Z;

[0076] Measure along the first direction: measure the straight-line distance between the starting point and the ending point of the part of the diaphragm extending outward relative to the pole piece in the first direction Z;

[0077] Measurement tool: high-precision optical measuring instrument, vernier caliper, microscope with image analysis software or X-ray tomography system can be used for measurement, ensuring that the measurement accuracy is not less than 0.01mm;

[0078] Measurement environment: The measurement should be carried out at standard room temperature (20-25℃) and in a dry environment to avoid affecting the measurement results due to material deformation or moisture absorption.

[0079] It should be noted that L1 refers to the minimum straight-line distance between the first welding mark and the first end of the lead-out portion along the first direction Z (i.e., the extension direction of the cell body towards the through hole), which is used to represent the relative position relationship between the welding area and the tab connection point.

[0080] The specific measurement method of L1 is as follows:

[0081] Sample preparation: Fix the battery to be tested on the sample table of the X-ray CT detection equipment, adjust the scanning area to align with the area on the shell where the through hole is provided, i.e., the connection part of the pole and the lead-out portion; set appropriate X-ray source voltage, current and geometric magnification, control the spatial resolution to be not less than 10 μm, and preferably to 5 μm or higher, to ensure that the structural details of the welding area can be clearly distinguished;

[0082] Determine the first direction: define the direction of the cell body towards the through hole as the first direction;

[0083] Reconstruct the image: start scanning, obtain the three-dimensional data of the battery, and generate a longitudinal section image along the first direction through image reconstruction algorithm;

[0084] Identify and calibrate the position: in the reconstructed image, identify the first welding mark on the lead-out portion as the closest end boundary point to the inside of the cell along the first direction and mark it as point A; identify the position where the lead-out portion starts to connect the tab (i.e., the first end) and mark the end point of the lead-out portion closest to the cell body in the first direction as point B;

[0085] Measure L1: in the first direction Z, measure the minimum straight-line distance between point A and point B, which is the minimum distance L1; to ensure that the measured L1 is the "minimum distance", the longitudinal section should be reconstructed at multiple angles (e.g., every 30° or 45°) around the through hole, and the section with the smallest L1 value should be selected as the final measurement result.

[0086] It should be noted that the cell is the component in the battery where electrochemical reactions occur, and it is the smallest unit in the battery that can perform electrochemical reactions such as charging / discharging. The cell usually includes a positive tab, a negative tab, and a separator.

[0087] The plurality of tabs 311 includes two types of tabs 311 with opposite polarities, i.e., positive tabs 311 and negative tabs 311, and the separator 312 is located between the positive tabs 311 and the negative tabs 311; the cell 3 works by moving metal ions between the positive tabs 311 and the negative tabs 311. The cycle process of the cell 3 is the process of moving metal ions from the positive tabs 311 to the negative tabs 311 and then from the negative tabs 311 to the positive tabs 311.

[0088] The diaphragm 312 serves as an insulation layer to prevent internal short circuit of the battery cell caused by contact between the positive electrode sheet 311 and the negative electrode sheet 311, and as a semi-permeable layer to prevent the passage of large molecules while allowing the passage of small charged ions.

[0089] The lead-out portion 32 refers to a conductive connection structure in the cell main body 31 for realizing the conduction of the internal electrode potential to the outside, one end of which is connected to the electrode sheet 311 (positive electrode sheet or negative electrode sheet) in the cell main body 31, and the other end of which extends to the through hole 12 area of the shell 1 and realizes electrical connection with the external pole 2. The lead-out portion 32 is one of the key paths for the conduction of the internal current of the cell. The lead-out portion 32 is usually a metal strip structure, and the material can be selected from aluminum, copper, nickel or their alloys.

[0090] The shell 1 includes a shell body 1A and a cover plate 1B, one end of the shell body 1A is provided with an opening, the shell 1 has an opening, and the cover plate 1B is arranged on the opening and forms a containing cavity 10 with the shell body 1A.

[0091] In the first embodiment, the first side wall 11 is arranged on the shell body 1A, that is, the through hole 12 is arranged on the shell body 1A.

[0092] In other embodiments, the first side wall 11 can also be arranged on the cover plate 1B, that is, the through hole 12 is arranged on the cover plate 1B.

[0093] It should be noted that the shell body is used to package the cell and electrolyte and other components. The shell body can be various shapes and various sizes, such as rectangular prism, hexagonal prism, etc., and the shape of the shell body can be determined according to the specific shape and size of the cell. The material of the shell can be various, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0094] It should be noted that the cover plate refers to a component that covers the open end of the shell to isolate the accommodation space inside the shell from the external environment. The shape of the cover plate can be adapted to the shape of the shell to cooperate with the shell to achieve isolation. The cover plate can be made of a material with certain hardness and strength (such as aluminum alloy).

[0095] It should be noted that the pole is used to electrically connect the cell inside the shell and the external device (adjacent battery or other electrical equipment) outside the shell. The cell can be connected to the pole through the cell output end (generally a tab) to discharge the external device, and the external power supply can charge the cell through the pole and the cell output end; the pole can be directly electrically connected with the cell tab, or can be electrically connected with the tab through a metal adapter plate. The pole can be a metal material including but not limited to copper, aluminum, aluminum alloy, copper-aluminum alloy, etc.

[0096] Referring to Figures 2-7In the first embodiment, the lead-out portion 32 is a tab 321, which is electrically connected to the pole 2 through the first solder 101.

[0097] The tab 321 has good bending performance, can adapt to the complex spatial layout inside the battery, is easier to adjust the position during assembly, and can avoid accidental lapping with the shell 1 due to excessive bending or space limitation, thereby helping to reduce the risk of short circuit and improve the overall safety of the battery. Moreover, the lead-out portion 32 can be directly welded to the pole 2, which eliminates the need for connection of the traditional structure through the connecting sheet or other intermediate conductor, reduces the number of welding between the battery cell 3 and the pole 2, not only reduces the process complexity, but also improves the production efficiency and product consistency. At the same time, due to the reduction of the number of intermediate connecting components and welding points, the current transmission path is more direct, and the contact resistance is reduced, thereby helping to reduce the overall internal resistance of the battery and improving the charge and discharge efficiency and power performance of the battery.

[0098] In some embodiments, the second end 202 is spaced apart from the through hole 12, satisfying 2≤L1 / H≤28.

[0099] Due to the spacing between the tab and the through hole 12, the tab may be slightly displaced during assembly or use, thereby increasing the risk of lapping the tab with the pole of opposite polarity in the battery cell 3. By increasing the value of H (i.e., increasing the distance between the edge of the pole piece 311 and the edge of the diaphragm 312), a larger safety space can be provided for the tab to prevent internal short circuit problems caused by tab displacement; that is, by spacing the second end 202 from the through hole 12, the upper limit of the L1 / H relationship can be reduced.

[0100] In the second direction Y, the spacing distance between the second end 202 and the through hole 12 is b, satisfying 0.4mm≤b≤4.5mm. By setting an appropriate b value range, the risk of tab breakage or tearing can be reduced, and the safety distance between the tab and the battery cell 3 can be ensured to improve the safety performance of the battery.

[0101] b can be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.5mm, etc. Any value satisfying 0.4mm≤b≤4.5mm.

[0102] The tab 321 comprises a first connecting portion 3211, a welding portion 3212 and an extension portion 3213 connected in sequence, the welding portion 3212 is welded with the pole 2 and forms a first welding mark 101, a side surface of the welding portion 3212 facing the pole 2 is a first surface 301, a side surface of the welding portion 3212 away from the pole 2 is a second surface 302, an end of the first connecting portion 3211 away from the welding portion 3212 is a first end 201, and an end of the extension portion 3213 away from the welding portion 3212 is a second end 202; the extension portion 3213 has a third surface 303 and a fourth surface 304, the third surface 303 is connected with the first surface 301, and the fourth surface 304 is connected with the second surface 302.

[0103] Preferably, along the extension direction Q of the tab 321 after being flattened, the distance between the second end 202 and the first welding mark 101 is L2, which satisfies: 0.2mm≤L2≤5.5mm. By limiting the value range of L2, a reasonable distance is maintained between the welding area of the tab and the leading end (i.e. the second end 202) of the tab. If L2 is too small, the welding point of the tab may be too close to the main body of the battery cell 3, increasing the risk of contact with the tab 311 of opposite polarity; and if L2 is too large, the tab may be loose and prone to deviation, also posing a risk of short circuit due to overlap; therefore, setting an appropriate range of L2 helps to maintain a safe distance between the tab and the battery cell 3, further reducing the possibility of internal short circuit of the battery.

[0104] L2 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm, 5.1mm, 5.2mm, 5.3mm, 5.4mm, 5.5mm, etc., any value satisfying 0.2mm≤L2≤5.5mm.

[0105] It should be noted that the extension direction of the tab after being flattened refers to regarding the tab as a flexible conductive sheet, completely flattening it without stretching or compression, so that it is in a two-dimensional plane state. In this state, the extension direction of the tab after being flattened is the direction from the tail end of the tab to the leading end of the tab in the plane. The extension direction of the tab after being flattened is perpendicular to the normal direction of the end surface of the tab leading out of the main body of the battery cell, and is located in the plane in which the tab is flattened.

[0106] The specific measurement method of L2 is as follows:

[0107] Tab flattening: fully unfolding the tab of the battery cell to a natural flat state to avoid affecting the measurement results due to bending or deformation;

[0108] Determining the first weld mark position: identifying the position of the first weld mark closest to the second end on the tab formed by the welding process as the first weld mark reference point through visual or microscopic imaging means;

[0109] Determining the second end position: defining the end point of the free end of the tab as the second end reference point;

[0110] Measuring along the extension direction: in the flattened state of the tab, measuring the straight-line distance between the first weld mark reference point and the second end reference point along the length direction of the tab (i.e. the direction of the tab extending out of the cell body), which is L2;

[0111] Measuring tool: high-precision optical measuring instrument, vernier caliper, digital caliper or laser ranging equipment can be used for measurement, ensuring that the measurement accuracy is not less than 0.01mm.

[0112] Measurement environment: the measurement should be carried out in a standard room temperature (20-25℃) and dry environment to avoid deformation of the tab material or measurement error due to changes in temperature and humidity.

[0113] The extension part 3213 has a staggered structure, and the staggered structure includes a plurality of tab pieces 3201 stacked, at least two tabs in the plurality of tab pieces 3201 having different lengths;

[0114] In the staggered structure of the extension part 3213, the length difference between the tab piece 3201 with the longest length and the tab piece 3201 with the shortest length is a, and the distance between the second end 202 and the through hole 12 is b, satisfying: 0.1≤a / b≤16.

[0115] If the value of b remains unchanged and the value of a is too large, it will cause the edge of the tab to extend too much in the direction of the through hole 12, increasing the risk of contact or overlap with the hole wall; if the value of a remains unchanged and the value of b is too large, it means that the hole diameter of the through hole 12 is too large, reducing the structural strength of the shell 1; by limiting 0.1≤a / b≤16, the structural strength of the shell 1 can be ensured while avoiding short circuit between the tab and the shell 1, ensuring electrical safety.

[0116] It should be noted that the "staggered structure" of the extension part 3213 is not caused by the difference in the length of the tab sheet 3201 itself, but refers to the relative position of the tab 321 in the length direction during the stacking process of the battery cell. Even if the length of the tab sheet 3201 of each battery cell is consistent during manufacturing, due to the thickness of the battery cell body 31 itself, the thickness will have a cumulative effect in the stacking direction during the stacking process, causing the relative position of the tab sheet in the length direction to shift or stagger, thereby forming a staggered structure of the tab 321 in the spatial position. The formation of the staggered structure is mainly affected by the number of stacked layers, the thickness of the battery cell body, and the arrangement of the tab, and is a spatial arrangement phenomenon naturally occurring during the stacking process.

[0117] Preferably, 0.5mm≤a≤8mm. a can be any of 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5mm, 5.2mm, 5.4mm, 5.6mm, 5.8mm, 6mm, 6.2mm, 6.4mm, 6.6mm, 6.8mm, 7mm, 7.2mm, 7.4mm, 7.6mm, 7.8mm, 8mm, etc. that satisfy 0.5mm≤a≤8mm.

[0118] Preferably, 0.1mm≤b≤5mm. b can be any of 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5mm, etc. that satisfy 0.5mm≤a≤8mm.

[0119] In the first embodiment, the tab 321 further includes a first bending part 3214, the first connecting part 3211, the first bending part 3214, the welding part 3212 and the extension part 3213 are connected in sequence, that is, the first connecting part 3211 is connected through the first bending part 3214 and the welding part 3212. The first bending part 3214 is formed with a first open slot 32141.

[0120] It can be understood that the opening groove refers to a recessed part with a specific shape and size formed on the bending part; this recessed part can have different shapes, such as semicircular, U-shaped, V-shaped, etc., and the groove bottom of the opening groove refers to the deepest place of the recessed part, i.e., the position farthest from the opening groove.

[0121] Referring to Figures 5 to 9 In the first embodiment, further, the tab 321 further includes a second bending part 3215, the first connecting part 3211, the second bending part 3215, the first bending part 3214, the welding part 3212 and the extension part 3213 are sequentially connected, that is, the first connecting part 3211 is connected through the second bending part 3215 and the first bending part 3214. The second bending part 3215 is formed with a second opening groove 32151.

[0122] In the first embodiment, further, the tab 321 further includes a second connecting part 3216, the first connecting part 3211, the second bending part 3215, the second connecting part 3216, the first bending part 3214, the welding part 3212 and the extension part 3213 are sequentially connected, that is, the second bending part 3215 is connected through the second connecting part 3216 and the first bending part 3214.

[0123] Preferably, along the extension direction Q of the tab 321 after being flattened, the distance between the second end 202 and the first welding mark 101 is L2, the size of the first welding mark 101 is L3, and the size of the tab 321 is L4, which satisfies: 0.04≤(L2+L3) / L4≤0.8.

[0124] By limiting the size of (L2+L3) / L4, the proportion of the tab welding area in the entire tab can be limited. When 0.8≤(L2+L3) / L4, it means that the welding area is too close to the battery cell 3 or the tab is too short as a whole, which is easy to cause the tab to overlap with the male tab 311 and cause short circuit; and when (L2+L3) / L4≤0.0, it may cause the tab to be too long and the space utilization to be low. By setting 0.04≤(L2+L3) / L4≤0.8, it can be ensured that the tab will not accidentally contact the battery cell 3 due to position deviation during assembly, thereby improving the internal insulation safety of the battery and further reducing the possibility of internal short circuit of the battery.

[0125] It should be noted that "L3" refers to the length dimension of the first welding mark formed on the surface of the tab after the tab is welded with the pole, which is used to represent the coverage range of the welding area on the tab.

[0126] The specific measurement method of L3 is as follows:

[0127] Tab flattening: the tab after welding is taken off from the battery cell and completely unfolded, so that it is in a natural flat state;

[0128] Identifying the first welding mark area: identifying the starting point and the ending point of the first welding mark on the tab surface by visual or microscopic imaging means, which is usually manifested as a heat-affected zone or a welding indentation during the welding process;

[0129] Determining the length direction of the welding mark: in the flattened state of the tab, measuring the straight-line distance between the starting point and the ending point of the first welding mark along the length direction of the tab (i.e. the direction in which the tab extends from the battery body); the measured length of the first welding mark is L3.

[0130] Measuring tool: high-precision optical measuring instrument, vernier caliper, microscope with image analysis software, or laser ranging equipment can be used for measurement, ensuring that the measurement accuracy is not less than 0.01 mm;

[0131] Measurement environment: the measurement should be carried out in a standard room temperature (20-25°C) and dry environment to avoid deformation of the tab material or measurement error caused by changes in temperature and humidity.

[0132] It should be noted that "L4" refers to the total length of the tab from the first end to the second end, which is used to represent the effective length of the tab as a whole.

[0133] The specific measurement method of L4 is as follows:

[0134] Flattening the tab: completely unfolding the tab to make it in a natural flat state, avoiding the influence of measurement caused by bending or deformation;

[0135] Determining the first end and the second end: the "first end" is the connection between the tab and the battery body;

[0136] The "second end" is the end of the extension away from the welding part, i.e. the end of the free end of the tab;

[0137] Measuring along the extension direction: in the flattened state of the tab, measuring the straight-line distance between the first end and the second end along the length direction of the tab; the measured total length of the tab is L4.

[0138] Measuring tool: high-precision optical measuring instrument, digital caliper, or laser ranging equipment can be used for measurement, ensuring that the measurement accuracy is not less than 0.01 mm;

[0139] Measurement environment: the measurement should be carried out in a standard room temperature (20-25°C) and dry environment to avoid the influence of measurement results caused by thermal expansion and contraction or moisture absorption and deformation of the material.

[0140] More preferably, 0.02≤L2 / L3≤3.5.

[0141] The first welding mark 101 is a key connection point for realizing current transmission between the tab and the pole 2, and defines the lower limit of the L2 / L3 ratio, which can avoid the welding area being too small or too close to the end (i.e., the second end 202) of the tab 321, thereby ensuring that the welding area is large enough to ensure welding strength and stable and reliable welding quality, and preventing problems such as virtual welding and falling caused by too small welding points or improper positions. Defining the upper limit of the L2 / L3 ratio can prevent the welding area from being too concentrated on the first end (the first end 201) of the tab 321 or near the battery cell 3, thereby leaving enough insulation space for the tab 321 and effectively avoiding accidental contact between the tab and the polar plate 311 or cover body with opposite polarity, thereby improving the safety of the battery.

[0142] The groove bottom of the first open slot 32141 has a first mark point 501.

[0143] Preferably, along the extension direction Q of the tab 321 after flattening, the minimum distance between the first mark point 501 and the first welding mark 101 is L5, which satisfies: 0.5mm≤L5≤4mm.

[0144] The first bending part 3214 can make the tab better adapt to the limited space layout between the shell 1 and the battery cell 3 during assembly; and by controlling the distance L5 between the groove bottom of the first open slot 32141 and the first welding mark 101, the tab can be ensured to be reasonably bent and folded in the accommodating cavity 10 without excessive stacking or deviation, thereby more effectively utilizing the internal space of the battery and improving the energy density. Too small L5 value will cause the bending area to be too close to the welding point, which is easy to cause local stress concentration and make the tab close to the polar plate 311 in the battery cell 3, increasing the risk of short circuit; and too large L5 value may cause the tab to be loose and unstable in positioning. By limiting L5 to a reasonable range, accidental contact between the tab and the polar plate 311 in the battery cell 3 with opposite polarity can be avoided, thereby improving the safety and insulation performance of the battery.

[0145] L5 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, etc. that satisfy 0.5mm≤L5≤4mm.

[0146] It should be noted that L5 refers to the straight-line distance between the first mark point and the first welding mark along the extension direction of the tab after flattening. The first mark point is the groove bottom point of the first open slot formed on the first bending part, which is used to represent the key positioning feature in the tab bending structure.

[0147] The specific measurement method of L5 is as follows:

[0148] Tab flattening: after the welding is completed, the tab is removed from the battery cell and fully unfolded along its natural extension direction, so that it is in a flat state, avoiding the influence of bending or deformation on the measurement accuracy;

[0149] Identifying the first bending part and the first opening slot: identifying the first bending part on the tab by visual or microscopic imaging, and further positioning the first opening slot formed thereon;

[0150] Determining the first mark point: defining the slot bottom position of the first opening slot as the first mark point, which is usually the geometric lowest point or center point of the slot structure;

[0151] Identifying the first welding mark: identifying the position of the first welding mark formed by the welding process on the tab closest to the first mark point as the first welding mark reference point by visual, microscopic imaging or X-ray detection;

[0152] Measuring along the extension direction: in the flat state of the tab, measure the straight-line distance between the first mark point and the first welding mark reference point along the length direction of the tab (i.e. the direction of the tab extending from the battery cell body), and the measured distance is L5.

[0153] Measuring tool: high-precision optical measuring instrument, microscope with image analysis software or laser ranging equipment can be used for measurement, ensuring that the measurement accuracy is not less than 0.01mm;

[0154] Measurement environment: the measurement should be carried out in standard room temperature (20-25℃) and dry environment, avoiding the deformation of the tab material or measurement error caused by temperature and humidity changes.

[0155] The slot bottom of the second opening slot 32151 has a second mark point 502.

[0156] Preferably, along the extension direction Q of the flattened tab 321, the distance between the first mark point 501 and the second mark point 502 is L6, which satisfies: 1.5mm≤L6≤11mm.

[0157] The tab 321 can need to go through multiple bending during the battery internal assembly process to adapt to the spatial layout. If L6 is too large, it means that the distance between the first bending part 3214 and the second bending part 3215 is too far, resulting in an increase in the overall length of the tab, which will occupy more valuable space when arranged inside the accommodation cavity 10, reduce the energy density of the battery, and is not conducive to compact design. If L6 is too small, it means that the distance between the first bending part 3214 and the second bending part 3215 is too close, which is easy to form a local stress superposition area, and is easy to cause material fatigue or even breakage during tab bending, assembly or use, reducing the structural strength and service life of the tab. By limiting L6 to a reasonable range, both the structural strength of the tab and the compact layout of the tab can be ensured without excessive folding or accumulation, which helps to improve the space utilization rate inside the accommodation cavity 10.

[0158] L6 can be 1.5mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5mm, 5.2mm, 5.4mm, 5.6mm, 5.8mm, 6mm, 6.2mm, 6.4mm, 6.6mm, 6.8mm, 7mm, 7.2mm, 7.4mm, 7.6mm, 7.8mm, 8mm, 8.2mm, 8.4mm, 8.6mm, 8.8mm, 9mm, 9.2mm, 9.4mm, 9.6mm, 9.8mm, 10mm, 10.2mm, 10.4mm, 10.6mm, 10.8mm, 11mm, etc. Any numerical value that satisfies 1.5mm≤L6≤11mm.

[0159] The specific measurement method of L6 is as follows:

[0160] Tab flattening: remove the tab from the battery cell and fully unfold it along its natural extension direction to make it flat, avoiding affecting the measurement results due to bending or deformation;

[0161] Identify the first bending part and the second bending part: identify the first bending part and the second bending part on the tab by visual or microscopic imaging;

[0162] Identify the first opening slot and the second opening slot: identify the first opening slot on the first bending part and determine its slot bottom position as the first marker point; identify the second opening slot on the second bending part and determine its slot bottom position as the second marker point;

[0163] Determine the marker point position: define the slot bottom points of the two opening slots as the first marker point and the second marker point, respectively, and the marker point is the geometric lowest point or center point of each slot structure;

[0164] Along the extension direction: in the tab flattening state, the straight-line distance between the first mark point and the second mark point is measured along the length direction of the tab (i.e. the direction in which the tab extends from the body of the battery cell), and the measured distance is L6.

[0165] Measuring tool: a high-precision optical measuring instrument, a microscope combined with image analysis software, or a laser ranging device can be used for measurement, ensuring that the measurement accuracy is not less than 0.01 mm;

[0166] Measurement environment: the measurement should be carried out in a standard room temperature (20-25℃) and dry environment, avoiding deformation of the tab material or measurement error due to changes in temperature and humidity.

[0167] More preferably, along the first direction, the minimum distance from the second mark point to the side of the through hole close to the body of the battery cell is L7, satisfying: 0.5mm≤L7≤5mm.

[0168] L7 is too small, meaning that the second bending part 3215 is too close to the first end 201 of the tab 321, which is easy to cause the overall structure of the tab to deviate towards the body of the battery cell, increasing the possibility of contact between the tab and the pole piece 311 with opposite polarity in the battery cell 3; L7 is too large, meaning that the distance between the first end 201 (connected to the body of the battery cell 31) of the tab and the second bending part 3215 is far, resulting in an increase in the overall length of the tab, which will occupy more space when arranged inside the accommodating cavity 10, reducing the energy density of the battery and being not conducive to compact design. By limiting L7 to a reasonable range, it can not only reduce the possibility of accidental contact between the tab and the pole piece 311 with opposite polarity in the battery cell 3, but also help to improve the space utilization rate inside the accommodating cavity 10.

[0169] L7 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm, etc. satisfying 0.5mm≤L7≤5mm.

[0170] Reference Figures 2-11 In the first embodiment, the battery further comprises an insulating piece 4, which is arranged between the second end 202 and the through hole 12, satisfying: 4≤L1 / H≤30.

[0171] By adding the insulating member 4 to the tab 321 and / or the shell 1, the electrical connection between the tab 321 and the shell 1 can be insulated, and the insulation performance between the tab and the shell 1 is improved. Since the insulating member 4 is added as an additional safety barrier, the length of L1 can be appropriately reduced under the premise of ensuring sufficient insulation distance, and the main body of the battery cell and the tab are arranged more compactly without sacrificing safety, which helps to reduce the volume of the battery and improve the energy density. That is, by adding the insulating member 4, the lower limit of the L1 / H relationship can be improved.

[0172] Exemplarily, the material of the insulating member 4 can be, but is not limited to, a plastic insulating member (such as polypropylene, polyethylene, and polyamide, etc.), a rubber insulating member (such as silicone rubber and fluororubber, etc.), a composite insulating member (such as glass fiber reinforced plastic and ceramic filled polymer, etc.), a coating type insulating member (such as epoxy resin coating and polytetrafluoroethylene coating, etc.), and a film type insulating member (such as polyester film and polyimide film, etc.).

[0173] In the first embodiment, the insulating member 4 is an insulating member not arranged on the surface of the tab 321. When the insulating member 4 is not arranged on the surface of the tab 321, the insulating member 4 can be a plastic insulating member, a rubber insulating member, a composite insulating member, etc.

[0174] In other embodiments, the insulating member 4 is an insulating member arranged on the surface of the tab 321. When the insulating member 4 is arranged on the surface of the tab, the insulating member can be a coating type insulating member coated on the surface of the tab 321; the insulating member can also be an insulating tape adhered to the surface of the tab 321; and the insulating member can also be an injection type insulating member arranged on the surface of the tab 321, such as an insulating sleeve, an insulating pad, etc.

[0175] Preferably, the insulating member 4 is connected to the third surface 303. By connecting the insulating member 4 and the third surface 303, the insulating member 4 can form a local insulation barrier between the tab and the through hole 12, preventing direct contact between the tab and the shell 1, thereby reducing the risk of short circuit; at the same time, the insulating member 4 arranged on the third surface 303 can provide certain physical support for the tab, reducing the direct effect of external stress on the tab, thereby reducing the risk of tearing of the tab due to bending or stretching, and improving the tearing strength of the tab.

[0176] It should be noted that the "insulating piece and the surface (for example, the second surface, the third surface, the fourth surface) are connected" refers to that a stable physical combination relationship is formed between the insulating piece and the surface of the tab, which can prevent the insulating piece from relative sliding, falling off or displacement during the assembly, transportation or use of the battery. The connection relationship is not limited to direct contact, but also includes fixed connection through an intermediate layer (such as an adhesive layer, a coating layer). For example, when the insulating piece is an insulating tape, the "connection" specifically means that the insulating tape is adhered to the surface of the tab through the adhesive layer provided by the insulating tape, so as to achieve firm adhesion. When the insulating piece is an injection molded insulating sleeve or an insulating pad, the "connection" can mean that the insulating piece is fixed to the surface of the tab through heat melting, covering or buckling structure.

[0177] Preferably, the insulating piece 4 is connected to the third surface 303 and the fourth surface 304. The insulating piece 4 can provide more comprehensive electrical isolation protection for the tab, further prevent direct contact between the tab and the shell 1, and further reduce the risk of short circuit. At the same time, the third surface 303 and the fourth surface 304 are both provided with the insulating piece 4, which can better avoid external stress directly acting on the tab, thereby further reducing the risk of tearing of the tab caused by bending or stretching and further improving the tearing strength of the tab.

[0178] More preferably, the insulating piece 4 is connected to the third surface 303, the fourth surface 304 and the second surface 302. The insulating piece 4 can form a comprehensive insulating protection structure from both sides of the extension 3213 to the key area of the welding portion 3212, so that the insulating piece 4 can provide more comprehensive electrical isolation protection for the tab, further prevent direct contact between the tab and the shell 1, and further reduce the risk of short circuit. At the same time, such comprehensive insulating protection structure not only can prevent external factors from damaging the tab, but also can share the force applied on the tab as part of the overall structure, thereby further reducing the risk of tearing of the tab caused by bending or stretching and further improving the tearing strength of the tab.

[0179] The pole 2 has a fifth surface 305 facing the battery cell 3, the shell 1 has a sixth surface 306 facing the fifth surface 305, and at least part of the insulating piece 4 is located between the sixth surface 306 and the fifth surface 305.

[0180] By arranging part or all of the insulating piece 4 between the fifth surface 305 of the pole 2 and the sixth surface 306 of the shell 1, the insulating piece 4 can not only form an insulating barrier between the tab and the through hole 12 to prevent the tab from being short-circuited with the through hole 12, but also form an insulating barrier between the pole 2 and the shell 1, which blocks the possibility of accidental contact between the pole 2 and the shell 1, avoids short circuit failure caused by conduction between the pole 2 and the shell 1, and provides more comprehensive protection for the safe and stable operation of the battery.

[0181] In the first embodiment, along the first direction Z, the end of the insulating member 4 close to the main body 31 is a first insulating end 205, and the end of the through hole 12 close to the main body 31 is a first hole end 206. The distance between the first insulating end 205 and the pole 2 is greater than the distance between the second end 202 and the pole 2, and the distance between the first hole end 206 and the pole 2 is greater than the distance between the first insulating end 205 and the pole 2. That is, the bottom of the insulating member 4 exceeds the bottom of the second end 202 of the tab 321, but does not exceed the bottom of the through hole 12. In this way, the insulating member 4 can avoid the path of the electrolyte in the battery as much as possible, thereby reducing the risk of aging, corrosion or degradation of the insulating performance of the insulating member 4 due to long-term contact with the electrolyte, and improving the durability and service life of the insulating member 4.

[0182] In other embodiments, the distance between the first insulating end 205 and the pole 2 is greater than the distance between the first hole end 206 and the pole 2. That is, the insulating member 4 exceeds the bottom of the through hole 12. In this way, the insulating member 4 can better cover the key area between the through hole 12 and the pole 2, further block the contact between the tab and the hole wall of the through hole 12, and further improve the insulation performance. During the assembly or use of the battery, even if there is a slight displacement or deformation of the components, this arrangement can ensure that the tab and the cover are always effectively insulated and isolated, avoiding short circuit failure due to accidental contact, and effectively eliminating safety hazards during battery operation.

[0183] The area of the first welding mark 101 is S3, and the area of the fifth surface 305 is S4,

[0184] Preferably, 0.1≤S3 / S4≤0.6.

[0185] If S3 / S4 is too large, the welding area is too large, and the energy input during welding will also increase accordingly. If the energy is not properly controlled, it may cause the tab material to locally overheat or even melt through, thereby affecting the safety and reliability of the battery. A large welding area will generate a large stress concentration in the welding area, especially in the transition zone between the tab and the welding surface, which will increase the risk of tab tearing during use. If S3 / S4 is too small, the welding area is too small, the effective contact area of the welding point is reduced, and the welding strength is insufficient. By limiting S3 / S4 to a reasonable range, the welding point can be ensured to have sufficient contact area to withstand assembly stress and mechanical load during use, thereby improving the connection reliability between the tab and the pole 2 and preventing tab tearing caused by insufficient welding area.

[0186] Preferably, 30mm 2 ≤S3≤120mm 2 .

[0187] Preferably, 50mm 2 ≤S4≤1000mm 2.

[0188] The cross-sectional area of the through hole 12 perpendicular to the first direction Z is S5, and the area of the fifth surface 305 is S4.

[0189] Preferably, 0.4≤S5 / S4≤0.85.

[0190] By limiting S5 / S4 within a reasonable range, the cross-sectional area size of the through hole 12 can be matched with the bottom surface area of the pole 2, so that the through hole 12 can provide good mechanical support to the pole 2, reducing the risk of deformation such as tilting, deviation or local collapse of the pole 2 during assembly or use. When the through hole 12 provides good support to the pole 2, the pole 2 can be more stably installed inside the accommodation cavity 10, thereby reducing the distance L1 between the pole 2 and the battery cell 3; the smaller L1 is, the shorter the length of the tab is, and the free space of the tab in the accommodation cavity 10 is reduced, reducing the risk of the tab being overlapped with the opposite polarity tab 311 during bending or vibration, thereby reducing the probability of internal short circuit.

[0191] Preferably, 40mm 2 ≤S5≤700mm 2 .

[0192] Referring to Figures 8-9 , the first side wall 11 is provided with a second groove 112 away from the battery cell 3, the through hole 12 is arranged through the groove bottom of the second groove 112 along the first direction Z, and at least part of the pole 2 is arranged in the second groove 112.

[0193] The second groove 112 on the shell 1 communicates with the through hole 12, and part or all of the pole 2 is arranged in the second groove 112, so that the pole 2 is arranged closer to the battery cell body 31 of the battery cell 3, thereby shortening the spatial distance between the pole 2 and the battery cell body 31 of the battery cell 3; this arrangement helps to reduce the length (L1 value) between the tab drawn out from the battery cell 3 to the pole 2, thereby reducing the risk of the tab being torn during bending or stress.

[0194] In some embodiments, the pole 2 is a circular structure; and satisfies: 2≤L1 / H≤28.

[0195] The circular pole 2 has the advantages of good structural symmetry and uniform stress, and it is easier to achieve uniform stress distribution during welding and assembly, and the fixing effect of the circular pole 2 is good. At this time, by controlling L1 / H within a reasonable range, L1 value can be reduced as much as possible without sacrificing assembly space, thereby shortening the tab length, reducing the length of the free section of the tab, reducing the risk of the tab being overlapped with the opposite polarity tab 311 during bending or vibration, and thereby preventing the occurrence of internal short circuit.

[0196] In some embodiments, the number of the pole posts 2 is one; when the cross-sectional length of the pole post 2 is different from the cross-sectional width of the pole post 2, the cross-sectional length of the pole post 2 is J1, and the cross-sectional width of the pole post 2 is J2, it is satisfied that 1.2≤J1 / J2≤4; more preferably, 4mm≤J1≤30mm.

[0197] In some embodiments, the number of the pole posts 2 is multiple; when the cross-sectional length of any two pole posts 2 is different, and / or the cross-sectional width of any two pole posts 2 is different, it is satisfied that 5≤L1 / H≤30.

[0198] For the pole post 2 with inconsistent length and width, if the pole post 2 is too close to the battery cell 3 (i.e., the value of L1 is too small), the stress concentration of the tab lead-out path may be large due to the asymmetry of the pole post 2, increasing the risk of tab fracture during bending or use. By reasonably controlling the range of L1 / H and appropriately increasing the value of L1, the stress concentration problem of the tab root can be alleviated while ensuring the connection performance, and the mechanical strength and long-term reliability of the tab can be improved.

[0199] In the first embodiment, the number of the pole posts 2 is two, and the first side wall 11 has a sixth surface 306 facing away from the battery cell 3, and both of the two pole posts 2 are located on the side of the sixth surface 306 facing away from the battery cell 3.

[0200] When the two pole posts 2 are arranged on the same side surface of the shell 1, the corresponding two tabs are also located in the same region, and a certain mechanical synergistic effect can be formed during assembly, welding or use. This layout enables the two tabs to support and balance the stress when subjected to external forces (such as vibration and bending), effectively alleviating the risk of tearing or breaking of a single tab due to excessive local stress, and improving the overall structural stability of the tab. Since the synergistic stress capacity of the two tabs is enhanced, the value of L1 (the distance between the pole post 2 and the battery cell 3) can be reasonably reduced under the premise of ensuring the mechanical strength of the tab; after the value of L1 is reduced, the lead-out path of the tab from the battery cell 3 to the pole post 2 is shorter, reducing the length of the free section of the tab and reducing the possibility of the tab being overlapped with the female tab 311 due to deviation or vibration during use, thereby reducing the probability of internal short circuit.

[0201] The distance between the two pole posts 2 is L 15 ,

[0202] Preferably, 2mm≤L 15 ≤26mm.

[0203] By setting L 15The control is within a reasonable range, which can ensure that the two tabs form a good mechanical synergistic effect under stress, effectively disperse the stress concentration problem caused by tab bending, vibration or assembly process, and improve the overall mechanical strength and tear resistance of the tab assembly. If L 15 is too small, the distance between the two pole posts 2 and the tabs connected thereto is close, and in the case of assembly error or tab deviation, accidental contact between the positive and negative tabs or between the pole posts 2 and the opposite polar sheet 311 may occur, causing local short circuit or insulation failure. By setting the lower limit value of L 15 , the minimum safety distance between the two pole posts 2 can be ensured, and the electrical safety of the battery system is improved. If L 15 is too large, it may cause the two pole posts 2 to occupy too much space on the top or side of the shell 1, which is not conducive to the compact design of the overall structure of the battery, and increases the length of the tab wiring, which increases the assembly difficulty and manufacturing cost. By setting the upper limit value of L 15 , the layout of the pole post 2 can be optimized under the premise of ensuring the performance of the tab, and the space utilization and integration efficiency are improved.

[0204] L 15 may be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm, 19mm, 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, etc. Any numerical value that satisfies 2mm≤L 15 ≤26mm.

[0205] In the first embodiment, the battery further comprises a compression ring 9, and the pole post 2 is fixed to the shell 1 through the compression ring 9; and satisfies: 2≤L1 / H≤27.

[0206] The compression ring 9 is used to press and fix the pole post 2 on the shell 1, which can improve the fixing strength of the pole post 2; because the compression ring 9 enhances the fixing strength of the pole post 2, the pole post 2 will not displace or tilt even if it is close to the battery cell 3; therefore, under the premise of ensuring the stability of the pole post 2, L1 can be reasonably reduced, thereby shortening the tab lead-out length, reducing the bending stress, and improving the tab assembly adaptability; after the tab wiring path is shortened, the free length of the tab is also reduced, which reduces the risk of the tab being in contact with the polar sheet 311 of opposite polarity due to vibration or deformation during use; at the same time, the compression ring 9 structure can also serve as one of the insulation support members around the pole post 2, which helps to improve the sealing and insulation performance between the pole post 2 and the shell 1, and further prevents internal short circuit.

[0207] It should be noted that the compression ring can fix the battery cell in the shell of the battery by mechanical pressure to prevent displacement of the battery due to expansion or vibration during charging and discharging, and to ensure the stability of the battery structure. The compression ring is usually made of metal materials such as aluminum alloy, steel, or engineering plastics such as PA66 and PPS. In some compression rings made of metal materials, an insulating layer such as epoxy resin is sprayed on the surface of the compression ring as needed to avoid short circuit.

[0208] In some embodiments, the compression ring 9 and the shell 1 are an integral structure, satisfying 5≤L1 / H≤27. The integral compression ring 9 has higher structural rigidity and positioning accuracy, and can further reduce the value of L1 under the premise of ensuring the stability of the pole 2. This helps to shorten the lead-out length of the tab from the battery cell 3 to the pole 2, reduce the tab bending angle and free section length, reduce the risk of stress concentration, and improve the tab assembly adaptability and structural compactness.

[0209] In some other embodiments, the compression ring 9 and the shell 1 are a split structure, satisfying 2≤L1 / H≤25.

[0210] The compression ring 9 and the shell 1 are set as a split structure, which can realize independent processing and assembly of each component, facilitate positioning and installation of the pole 2, the compression ring 9 and the shell 1, and significantly improve the assembly efficiency and automation compatibility. Since there is a certain limit to the fixing strength of the split compression ring, when the pole 2 is close to the battery cell 3 (i.e., the value of L1 is too small), the pole 2 may be offset due to uneven stress or vibration, which may further cause stress concentration and even breakage of the tab bending. Therefore, by reasonably controlling L1 / H and appropriately increasing the value of L1, it is helpful to alleviate the stress concentration problem at the root of the tab, prevent tab tearing failure, and improve the long-term use reliability of the battery.

[0211] The following are the relevant test methods:

[0212] A tab breakage test method: an electric core made of a positive electrode sheet, a negative electrode sheet and a separator is assembled with a shell to form a battery, wherein the output end of the electric core at least partially extends into a through hole of the shell and is electrically connected with a pole provided at the through hole of the shell, and the pole is insulated from the shell. For different embodiments and comparative examples, 100 batteries of the same type are taken, wherein L1 and H are shown in Table 1, and the rest are the same. The batteries are tested by a electromagnetic vibration tester (MSK-TE917) according to the standard GB / T31467.3-2015. The vibration test is carried out in three directions, starting from the z axis, then the y axis, and finally the x axis. The test time of each direction is 21h. After 2h of vibration test, the battery is disassembled, and the tab breakage is observed. If the number of tab breakage layers / total number of tab layers in a single battery is greater than or equal to 1%, it is unqualified. If it is less than 1%, it is qualified. The qualification rate is calculated as (qualified battery number / total battery number) * 100%. If the qualification rate is greater than or equal to 98%, it is qualified. Otherwise, it is unqualified. The specific results are shown in Table 1.

[0213] A battery cell internal short circuit test method: an electric core made of a positive electrode sheet, a negative electrode sheet and a separator is assembled with a shell to form a battery, wherein the output end of the electric core at least partially extends into a through hole of the shell and is electrically connected with a pole provided at the through hole of the shell, and the pole is insulated from the shell. For different embodiments and comparative examples, 100 batteries of the same type are taken, wherein L1 and H are shown in Table 1, and the rest are the same. For each embodiment and comparative example, 100 batteries are taken, and the resistance between the positive electrode sheet and the negative electrode sheet is measured by using an insulation voltage drop tester (IDI 6161A). One end of the insulation voltage drop tester (IDI 6161A) is connected with the positive pole, and the other end is connected with the negative pole. The resistance is calculated if the resistance value is greater than or equal to 20MΩ, it is qualified. If the resistance value is less than 20MΩ, it is unqualified. The qualification rate is (qualified battery number / 100) * 100%. If the qualification rate is greater than or equal to 97%, it is qualified. Otherwise, it is unqualified. The specific test results are shown in Table 1 below.

[0214] The results are shown in the following table using the above test method:

[0215]

[0216]

[0217] As can be seen from Table 1, the experimental examples 1-21 satisfy 2≤L1 / H≤30, and the comparative examples 1-5 do not satisfy 2≤L1 / H≤30. The tab breakage test qualification rate and the battery short circuit test qualification rate of the experimental examples 1-21 are significantly better than those of the comparative examples 1-5.

[0218] Example Two

[0219] Reference Figures 12 to 13The battery provided in Embodiment Two is different from the battery provided in Embodiment One only in that the surface of the tab 321 is provided with the reinforcing rib 5.

[0220] Preferably, the distance L8 between the reinforcing rib 5 and the first welding mark 101 along the extension direction Q of the tab 321 after being flattened satisfies: 0.3mm≤L8≤4.5mm.

[0221] L8 can be 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.5mm, etc. satisfying 0.3mm≤L8≤4.5mm.

[0222] The reinforcing rib 5 provided on the tab 321 can enhance the mechanical strength of the whole tab, especially when the tab is subjected to bending, assembly or external impact, the tensile and tear resistance of the tab 321 can be improved, thereby prolonging the service life of the battery and improving the product reliability. If the value of L8 is too large, the reinforcing rib 5 is too far away from the first welding mark 101, and cannot effectively support the stress distribution of the welding part 3212 under stress, resulting in a significant reduction in the role of the reinforcing rib 5 in resisting tearing and enhancing structural strength. If the value of L8 is too small, the reinforcing rib 5 is too close to the first welding mark 101, and the reinforcing rib 5 will form a stress concentration zone near the welding area, affecting the uniformity of heat conduction and the ductility of the material of the welding point, which may cause welding failure or local cracking of the tab; by limiting L8 to a reasonable range, the reinforcing rib 5 and the welding area are kept at an appropriate distance, which can avoid stress concentration and ensure the structural integrity and connection reliability of the welding part 3212.

[0223] Preferably, the distance L9 between the reinforcing rib 5 and the first end 201 along the extension direction Q of the tab 321 after being flattened satisfies: 1.5mm≤L9≤6mm.

[0224] If L9 is too large, the reinforcing rib 5 is too far away from the first end 201, and cannot effectively support the tab in the area where the stress is most concentrated (such as near the bending or welding point), resulting in a significant reduction in the role of the reinforcing rib 5 in resisting tearing and enhancing structural strength; if the value of L9 is too small, the reinforcing rib 5 is adjacent to the first end 201, and a local stress superposition zone is easily formed in this area; material fatigue or even fracture is easily occurred during the bending, assembly or use of the tab, which greatly reduces the structural strength and service life of the tab. By limiting L9 to a reasonable range, the reinforcing rib 5 and the first end 201 are kept at an appropriate distance, which can avoid stress concentration and ensure the structural strength of the tab.

[0225] L9 can be 1.5 mm, 1.6 mm, 1.8 mm, 2 mm, 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm, 3 mm, 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm, 4 mm, 4.2 mm, 4.4 mm, 4.5 mm, 4.6 mm, 4.7 mm, 4.8 mm, 4.9 mm, 5 mm, 5.1 mm, 5.2 mm, 5.3 mm, 5.4 mm, 5.5 mm, 5.6 mm, 5.7 mm, 5.8 mm, 5.9 mm, 6 mm, or any numerical value satisfying 1.5 mm≤L9≤6 mm.

[0226] Preferably, the reinforcing rib 5 is arranged on the outer side of the first bending portion 3214.

[0227] The first bending portion 3214 is prone to stress concentration during the bending, assembling or using of the tab, which may cause material fatigue or even breakage. The reinforcing rib 5 arranged on the first bending portion 3214 can improve the mechanical strength of the tab in the bending area, prevent the bending area from tearing or breaking due to excessive stress, and improve the overall structural strength of the tab.

[0228] It should be noted that the "inner side" of the bending portion refers to the side surface facing the bending center when the tab is bent, i.e., the surface subjected to compressive stress during bending; the "outer side" of the bending portion refers to the side surface away from the bending center when the tab is bent, i.e., the surface subjected to tensile stress during bending.

[0229] Embodiment Three

[0230] Referring to Figures 14 to 15 The battery provided in Embodiment Three is different from the battery provided in Embodiment One only in that the plurality of tab pieces 3201 of the tab 321 are pre-fixed by the second welding mark 102.

[0231] The plurality of tab pieces 3201 may have certain gaps or misalignments in the unfixed state, which may cause uneven welding, small contact area, etc. during subsequent welding (first welding mark 101) with the pole 2. The pre-fixing by the second welding mark can effectively eliminate the relative displacement and gaps between the tab pieces 3201, so that the tab pieces 3201 can maintain a good alignment state during welding, thereby improving the welding quality and connection strength of the first welding mark 101; if the plurality of tab pieces 3201 are not pre-fixed, local tearing or breaking may occur due to uneven stress during bending or assembling. The pre-fixing of the plurality of tab pieces 3201 into a whole by the second welding mark can enhance the overall rigidity and anti-deformation ability of the tab 321, improve the structural stability and durability of the tab 321 under complex working conditions, and prolong the service life of the battery.

[0232] The minimum distance between the second welding mark 102 and the first end 201 along the extension direction Q of the flattened tab 321 is L 10 , satisfying: 0.1≤(L1-L 10 ) / L1≤0.7. By limiting (L1-L 10 ) / L1 within a reasonable range, the second welding mark can strengthen the strength of the tab while reducing the risk of tab overlap with the pole piece 311.

[0233] Embodiment Four

[0234] Referring to Figure 16 , the battery provided in Embodiment Four is only different from the battery provided in Embodiment One in that the tab 321 is provided with a fuse 6.

[0235] By providing the fuse 6 on the tab 321, the electrical connection between the tab and the pole 2 can be automatically disconnected when the battery is in abnormal working conditions such as short circuit or overcurrent, thereby effectively cutting off the fault current path and reducing the risk of thermal runaway of the battery.

[0236] , the second direction Y is perpendicular to the first auxiliary plane 400, along the second direction Y, the tab 321 forms a first orthographic projection 401 on the first auxiliary plane 400, the area of the first orthographic projection 401 is S1, the fuse 6 forms a second orthographic projection 402 on the first auxiliary plane 400, and the area of the second orthographic projection 402 on the first auxiliary plane 400 is S2.

[0237] Preferably, 0.3≤S2 / S1≤0.7.

[0238] When the S2 / S1 ratio is too large, it means that the area occupied by the fuse 6 region is large, and the size of the fuse 6 is large relative to the entire tab; the large size of the fuse 6 leads to low resistance, which may not be able to melt in time when a short circuit or overcurrent occurs, and cannot play the role of cutting off the circuit, reducing the safety of the battery; the large size of the fuse 6 region enhances the rigidity of the tab at that position, making it difficult for the tab to naturally bend at that position, which may cause the tab to deform, tear or not be installed in place, affecting the assembly quality. When the S2 / S1 ratio is too small, it means that the area occupied by the fuse 6 region is small, and the size of the fuse 6 is small relative to the entire tab; the small size of the fuse 6 leads to insufficient conduction cross-sectional area, which may cause local overheating or voltage drop during normal charging and discharging, affecting the performance and service life of the battery; the mechanical strength of the small size fuse 6 is prone to breakage during tab bending, assembly or use, affecting the overall conductivity and reliability of the tab.

[0239] Along the first direction Z, the distance between the fuse 6 and the first welding mark 101 is L 12 .

[0240] Preferably, 1mm≤L12 ≤10mm.

[0241] When L 12 is too large, it means that the fuse 6 is far away from the first welding mark 101 (the main welding area) and is far away from the main welding point, and may be close to the first end 201 (the tab root) or the vicinity of the main body of the battery cell 3. In the case of short circuit or overcurrent, if the fuse 6 is far away from the main welding point, the time for the fuse 6 to sense the abnormal current will be delayed, resulting in delayed fusing response, reducing the timeliness and reliability of circuit protection. If the fuse 6 is too close to the tab root, the area where the fuse 6 is arranged on the tab is prone to form a stress concentration area during the tab bending process, increasing the risk of tab fracture in this area, affecting the service life. When L 12 is too small, it means that the fuse 6 is very close to the first welding mark 101 (the main welding area) and almost abuts the main welding point. The temperature fluctuation or local heating near the main welding point may be mistaken for a fault signal, causing the fuse 6 to be mistakenly fused in a non-abnormal state, affecting the stable operation of the battery system. The main welding point area itself is one of the stress concentration positions of the tab, and if the fuse 6 is arranged too close, it will form a superimposed stress in this area, which is prone to cause the tab to crack or fall off near the welding point. By limiting L 12 to a reasonable range, the fuse 6 is kept at an appropriate distance from the main welding point, which facilitates the bending of the tab at the appropriate position and avoids internal short circuit.

[0242] L 12 may be any value that satisfies 1mm≤L 12 ≤10mm.

[0243] In the first direction Z, the distance between the fuse 6 and the first end 201 is L 13 .

[0244] Preferably, 1.5mm≤L 13 ≤10mm.

[0245] When L 13 is too large, it means that the fuse 6 is very close to the first welding mark 101 (the main welding area) and almost abuts the main welding point. The temperature fluctuation or local heating near the main welding point may be mistaken for a fault signal, causing the fuse 6 to be mistakenly fused in a non-abnormal state, affecting the stable operation of the battery system. The main welding point area itself is one of the stress concentration positions of the tab, and if the fuse 6 is arranged too close, it will form a superimposed stress in this area, which is prone to cause the tab to crack or fall off near the welding point. When L 13When the value of L is too small, it means that the fuse 6 is too close to the first welding point 101, far away from the main welding area, and possibly close to the first end 201 (the tab root) or the cell body of the cell 3. In the case of short circuit or overcurrent, if the fuse 6 is far away from the main welding point, the fuse 6 will lag behind in sensing the abnormal current, resulting in delayed fusing response and reducing the timeliness and reliability of circuit protection. If the fuse 6 is too close to the tab root, the area where the fuse 6 is arranged on the tab is prone to stress concentration during tab bending, increasing the risk of tab fracture in this area and affecting the service life. By limiting the value of L to a reasonable range, the fuse 6 is kept at an appropriate distance from the first end 201, facilitating tab bending at the appropriate position and avoiding internal short circuit. 13 The value of L is limited to a reasonable range, so that the fuse 6 is kept at an appropriate distance from the first end 201, facilitating tab bending at the appropriate position and avoiding internal short circuit.

[0246] L 13 may be 1.5mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc. to satisfy 1.5mm≤L 13 ≤10mm.

[0247] Example Five

[0248] Referring to Figure 17 , the battery provided in Example Five is only different from the battery provided in Example One in that a transition angle is arranged between the tab 321 and the cell body, and the transition angle is a rounded angle.

[0249] In the traditional tab structure, the connection between the tab and the cell body (i.e. the tab root) is usually a right angle or a sharp angle transition, which is prone to stress concentration and can easily cause material fatigue or even fracture during assembly, bending or use. By introducing a rounded angle transition structure between the tab 321 and the cell body, the original sharp or right angle structure is changed to a rounded angle connection with a certain curvature, which can disperse local stress, improve the mechanical strength and tear resistance of the area, thereby prolonging the service life of the tab and the battery.

[0250] Preferably, the radius of the rounded angle is r, satisfying: 0.8mm≤r≤8.5mm.

[0251] If the value of r is too large, it will reduce the effective contact area and mechanical support capacity of the tab root, causing the tab to easily deviate or deform under stress, affecting the connection reliability between the tab and the tab 311 of the cell 3. If the value of r is too small, it will cause severe stress concentration in the tab root area, easily causing material fatigue or even tab fracture, affecting the service life of the battery.

[0252] Example Six

[0253] Referring to Figures 18-19 , the battery provided in Example Six is only different from the battery provided in Example One in that the side of the tab 311 close to the tab 321 is provided with an insulating glue 7.

[0254] The insulating glue 7 is arranged on the side of the pole piece 311 close to the pole lug 321, so as to isolate the direct contact between the pole lug and the pole piece 311.

[0255] The size of the insulating glue 7 is K1 and the size of the battery cell 3 is K2 along the first direction Z.

[0256] Preferably, 0.005≤K1 / K2≤0.05 is satisfied.

[0257] If the size of the insulating glue 7 is too small (i.e., K1 / K2 is too low), the insulating glue 7 can not be able to completely cover the potential contact area between the pole lug and the pole piece 311; and if the size is too large (i.e., K1 / K2 is too high), the compactness of the pole piece 311 stacking or winding structure can be affected. By limiting K1 / K2 within a reasonable range, the insulating glue 7 can not only provide a sufficient insulation protection layer in the key area, improve the electrical isolation capability between the pole lug and the pole piece 311, and prevent internal short circuit problems caused by lap or deviation, but also avoid interference with the overall structure of the battery cell 3, thereby improving the safety and stability of the battery system without sacrificing the energy density.

[0258] The size of the pole lug 321 is K3 and the size of the through hole 12 is K4 along the third direction X.

[0259] Preferably, 0.3≤K3 / K4≤0.8.

[0260] When K3 / K4 is too large, the size of the pole lug 321 is too large, and as an electrified component, the pole lug 321 is prone to interference, friction, or even jamming when penetrating into the through hole 12, increasing the assembly difficulty, which can cause the pole lug to deform or tear, affecting the product yield; the pole lug 321 is squeezed in the too tight through hole 12, which can cause local stress concentration or material yield, reducing the overall mechanical strength of the pole lug and increasing the risk of fracture. When K3 / K4 is too small, the size of the pole lug 321 is too small, and there can be a large gap in the through hole 12, which is prone to deviation, shaking, or even tilting, affecting the welding alignment accuracy between the pole lug and the pole 2; the pole lug is not firmly fixed in the through hole 12, which can deviate due to vibration or assembly error, increasing the risk of contact with the metal part of the shell 1 or other polar components, causing internal short circuit; the pole lug has insufficient support in the through hole 12 and is prone to deformation or fracture during subsequent bending or use, affecting the long-term reliability of the pole lug.

[0261] The size of the battery cell 3 is K5 along the third direction X.

[0262] Preferably, 0.1≤K3 / K5≤0.45.

[0263] When K3 / K5 is too large, it indicates that the tab 321 has a large size, i.e., the tab width is relatively wide relative to the size of the battery cell 3; the tab size is too wide, the overall rigidity is enhanced, and it is not easy to bend or adjust the angle during assembly, which can easily cause misinstallation or stress concentration, increasing the risk of fracture. When K3 / K5 is too small, it indicates that the tab 321 has a small size, i.e., the tab width is relatively narrow relative to the size of the battery cell 3; the tab width is too narrow, which means that the conductive path is narrowed, and the overcurrent capacity is low, affecting the charge and discharge capacity and power output performance of the battery; the tab width is too narrow, which can cause the mechanical strength of the tab to decrease, and the tab is prone to tearing or breaking during assembly, bending, or use, affecting the service life and reliability of the battery.

[0264] In the third direction X, the distance between the tab 321 and the end of the battery cell body 31 is K6.

[0265] Preferably, 10mm≤K6≤60mm.

[0266] K6 can be 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 22mm, 24mm, 26mm, 28mm, 30mm, 32mm, 34mm, 36mm, 38mm, 40mm, 42mm, 44mm, 46mm, 48mm, 50mm, 52mm, 54mm, 56mm, 58mm, 60mm, or any value satisfying 10mm≤K6≤60mm.

[0267] The tab is an electrically charged component, and if it comes into accidental contact with the shell 1 or other metal components during assembly or use, it can easily cause internal short circuit or even thermal runaway. By limiting K6 to a reasonable range, a reasonable distance can be maintained between the tab 321 and the end of the battery cell body 31, so that the tab can be prevented from being lapped with the shell 1 due to deviation, vibration, or deformation, thereby improving the electrical safety and insulation reliability of the battery system.

[0268] The tab has a staggered structure, and the staggered structure includes a plurality of tab pieces stacked.

[0269] The width of the tab piece 3201 is K7, and the width of the tab 321 is K8.

[0270] Preferably, 0.6≤K7 / K8≤0.9. That is, the plurality of tab pieces 3201 of the tab 321 do not completely overlap, but present a certain spatial stagger; in this way, during tab bending or assembly, the staggered structure presenting a certain spatial stagger can effectively prevent the tab from coming into accidental contact with the tab piece 311 of the battery cell 3 due to overall deviation during tab bending, thereby reducing the risk of internal short circuit and improving the electrical safety and insulation reliability of the battery system. After adopting the staggered structure, small gaps are left between the tab pieces 3201 of different widths, which is helpful for air flow and heat dissipation, and improves the heat dissipation conditions in the tab area.

[0271] It should be noted that the "staggered structure" mentioned by the tab has nothing to do with the difference in the width of the tab in the third direction (i.e. the stacking or winding direction), but refers to the fact that during the manufacturing process of the battery cell, even if multiple tabs have consistent width dimensions during design and manufacturing, due to manufacturing tolerances, equipment precision limitations or material deformation, etc., the tabs cannot be precisely aligned during the stacking or winding process, resulting in cumulative errors or positional offsets in the third direction, and thus forming a staggered distribution of the tabs in space.

[0272] Embodiment seven

[0273] Referring to Figure 20 The battery provided in embodiment seven is different from the battery provided in embodiment one only in that the surface of the tab 321 is bonded with the insulating tape 8.

[0274] By bonding the insulating tape 8 on the surface of the tab 321, the external support force and structural stability of the tab can be increased, the bending resistance, tensile resistance and tearing resistance of the tab can be improved, and the structural strength of the tab can be improved. The insulating tape can isolate the direct contact between the tab and the surrounding components, reduce the risk of short circuit caused by tab displacement, vibration or deformation, and improve the safety of the battery system.

[0275] The insulating tape 8 includes a first portion 81, a second portion 82 and a third portion 83 connected in sequence, the first portion 81 is provided with an adhesive and is bonded to the surface of the tab 321 by the adhesive, the second portion 82 is not provided with an adhesive, and the third portion 83 is provided with an adhesive and is bonded to the surface of the cell body 31 of the battery cell 3 by the adhesive.

[0276] The first portion of the insulating tape is firmly bonded to the surface of the tab lead-out portion 32, providing additional mechanical support for the tab, improving the tensile resistance and bending resistance of the tab, and further improving the structural strength of the tab; in combination with the second portion without adhesive as a flexible transition zone, the stress concentration problem generated during the bending process of the tab can be alleviated, the structural strength is improved while the necessary flexibility and assembly adaptability of the tab are retained; the third portion of the insulating tape is bonded to the surface of the cell body 31 of the battery cell 3 by the adhesive, forming a physical fixing point between the tab and the battery cell 3, which helps to limit the displacement range of the tab during assembly or use, preventing accidental contact with the male tab 311 due to vibration or deformation, thereby improving the electrical safety of the battery system.

[0277] The second portion 82 and the first end 201 are at least partially coincident in projection on the large face of the cell body 31; the second portion 82 is located in the region corresponding to the connection end (first end) of the tab 321 and the cell body 31, although it does not have an adhesive, it covers the key connection site, and can play a physical isolation and buffer protection role for the connection area of the first end and the cell during assembly, transportation and use, preventing connection failure or short circuit risk caused by external force or vibration.

[0278] It should be noted that the "large face" of the cell body refers to the two opposite surfaces with the largest area on the outer surface of the cell body, i.e. the main plane formed by the extension of the cell in the stacking or winding direction. This surface is usually the main area of the cell that contacts the inside of the battery case during assembly, and is also the main load-bearing surface of the cell that bears external forces inside the battery.

[0279] Embodiment Eight

[0280] Referring to Figure 21 The battery provided in Embodiment Eight is different from the battery provided in Embodiment One only in that the lead-out portion 32 includes a tab 321 and a transition piece 322, the first end 201 and the second end 202 are arranged on the tab 321, and the transition piece is arranged between the tab and the pole, the transition piece 322 and the pole 2 are welded to form the first welding mark 101, i.e. the tab 321 is indirectly connected to the pole 2 through the transition piece 322.

[0281] The transition piece, as an intermediate conductive connecting piece, can play a transition role between the tab and the pole, and is especially suitable for the case where the tab and the pole have different materials, large thickness difference or limited space layout, effectively improving the compatibility and consistency of the welding process.

[0282] The thickness of the transition piece is d.

[0283] Preferably, 0.5mm≤d≤4mm.

[0284] If the thickness of the transition piece is too small, its mechanical strength is insufficient, and it is easy to deform or break during welding or assembly, affecting the connection reliability; if the thickness is too large, it will increase the space occupation inside the battery, affect the overall energy density, and increase the welding difficulty, resulting in unstable welding quality; controlling the thickness of the transition piece within the range of 0.5mm to 4mm can achieve a good balance between mechanical strength, welding performance and space utilization, ensuring the reliability of the connection structure, and not affecting the overall design and performance of the battery.

[0285] d can be any value satisfying 0.5mm≤d≤4mm, such as 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, etc.

[0286] It should be noted that the adapter piece, as a conductive part of the battery, is mainly used to realize reliable connection and current transmission between the battery cells and the pole, and can maintain the relative position between the battery cells and the pole when the battery is vibrating or the temperature changes, preventing the connection point from loosening. Therefore, the material of the adapter piece usually considers both conductivity and light weight, for example, the adapter piece connecting the positive tab is usually made of aluminum or aluminum alloy (such as 1060 aluminum), and the adapter piece connecting the negative tab is usually made of copper or nickel-plated copper. For some high-power scenarios, some batteries may also use copper-aluminum composite materials to make adapter pieces.

[0287] Embodiment Nine

[0288] Referring to Figures 22 to 23 , the battery provided in Embodiment Nine is different from the battery provided in Embodiment Eight only in that the adapter piece 322 is a soldering aid piece, and the adapter piece 322 is connected to the side of the tab 321 away from the pole 2. By setting the adapter piece 322 as a soldering aid piece and setting the soldering aid piece on the side of the tab away from the pole 2, the presence of the soldering aid piece increases the heat conduction path of the soldering area of the tab and the pole 2, which helps to improve the soldering quality and soldering strength, prevent problems such as virtual welding and welding caused by local overheating or cold welding, and improve the fixing reliability between the tab and the pole 2.

[0289] Further, 0.1mm≤d≤0.5mm. By setting the soldering aid piece on the side of the tab 321 facing the main body 31 of the battery cell, the heat stress and mechanical stress generated during the soldering process can be effectively dispersed, and stress concentration at the root of the tab to cause material fatigue or even breakage can be avoided. By reasonably controlling the thickness d of the soldering aid piece, the soldering aid piece can provide sufficient support force without excessively increasing rigidity, so as to improve the soldering strength while retaining the necessary flexibility of the tab, preventing the tab from tearing and failing.

[0290] The groove bottom of the first open groove 32141 has a first mark point 501.

[0291] The minimum distance between the first mark point 501 and the soldering aid piece in the extension direction of the flattened tab is L 14 .

[0292] Preferably, 0.5mm≤L 14 ≤5mm.

[0293] L2 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.5mm, 4.6mm, 4.7mm, 4.8mm, 4.9mm, 5mm, etc. any value meeting 0.5mm≤L 14 ≤5mm.

[0294] The edge of the soldering sheet can cause damage or stress concentration to the tab during assembly or welding. By setting a reasonable L 14 distance, the soldering sheet and the first opening slot 32141 in the first bending part 3214 of the tab are kept at a certain interval, which can avoid mechanical damage to the bending area caused by the edge of the soldering sheet, thereby improving the overall structural integrity and reliability of the tab.

[0295] Embodiment ten

[0296] Referring to Figures 24-25 , the battery provided by embodiment nine is only different from the battery provided by embodiment one in that the side of the shell 1 facing the battery cell 3 is provided with a first recess 111, and the through hole 12 is arranged through the bottom of the first recess 111 along the first direction Z.

[0297] The first recess 111 on the shell 1 in communication with the through hole 12 can provide additional accommodation space for the tab, reduce the risk of the tab being overlapped with the shell 1 or the tab 311 during bending or vibration, and reduce the probability of internal short circuit.

[0298] Embodiment eleven

[0299] Referring to Figures 26 to 27 , embodiment eleven of the present application provides a battery pack, which comprises at least two batteries of any one of the above, and further comprises a conductive row 1000, and the adjacent two batteries are electrically connected through the conductive row 1000, and the conductive row 1000 is welded and fixed with the pole 2 through a third welding mark 103.

[0300] The distance between the third welding mark 103 and the first welding mark 101 is L 16 , preferably, 2.5mm≤L 16 ≤8.5mm.

[0301] In the process of assembling the battery, the third welding operation between the conductive bar 1000 and the pole 2 can affect the existing first welding 101 (i.e. the welding point between the tab and the pole 2) due to heat conduction or mechanical stress, resulting in uneven stress on the tab and even tearing. By arranging the L 16 The control is within a reasonable range, which can effectively isolate the heat affected zone and the mechanical stress range generated by the third welding, avoid the destructive effect of the third welding on the first welding 101, and ensure the welding strength of the tab is not disturbed, thereby improving the safety and reliability of the battery pack.

[0302] L 16 It can be 2.5mm, 2.6mm, 2.8mm, 3mm, 3.2mm, 3.4mm, 3.6mm, 3.8mm, 4mm, 4.2mm, 4.4mm, 4.6mm, 4.8mm, 5mm, 6.2mm, 6.4mm, 6.6mm, 6.8mm, 7mm, 7.2mm, 7.4mm, 7.6mm, 7.8mm, 8mm, 8.1mm, 8.2mm, 8.3mm, 8.4mm, 8.5mm, etc. Any value that satisfies 2.5mm≤L 16 ≤8.5mm.

[0303] Preferably, along the first direction Z, the third welding 103 and the first welding 101 are arranged in a staggered manner. By arranging the two weldings in a staggered manner, the mechanical strength and service life of the tab assembly can be improved.

[0304] The above is only the preferred embodiment of the present application, it should be noted that for ordinary skilled in the art, without departing from the technical principles of the present application, can make several improvements and substitutions, these improvements and substitutions should also be considered as the protection scope of the present application.

Claims

1. A battery, characterized in that, Having a first direction, a second direction, and a third direction that are perpendicular to each other, including: A housing having a receiving cavity, the housing having a first sidewall located in a first direction of the receiving cavity, the first sidewall having a through hole; pole; A battery cell includes a cell body and a lead-out portion. The cell body is disposed within a receiving cavity. The electrode post is disposed on the side of the through hole away from the cell body. The cell body includes a plurality of stacked electrode sheets and a separator located between two adjacent electrode sheets. The lead-out portion has a first end and a second end facing each other. The lead-out portion is disposed on the side of the cell body facing the through hole. The first end is connected to the electrode sheet. At least a portion of the lead-out portion is located within the through hole. The lead-out portion and the electrode post are welded to form a first solder mark. Wherein, along the first direction, the minimum distance between the diaphragm and the through hole is h1, the minimum distance between the electrode and the through hole is h2, and the minimum distance between the first solder mark and the first end is L1, H = h2 - h1, satisfying: 2 ≤ L1 / H ≤ 30.

2. The battery according to claim 1, characterized in that, The lead-out portion is a tab, which is electrically connected to the electrode post through the first solder mark.

3. The battery according to claim 2, characterized in that, The second end is spaced apart from the through hole, satisfying: 2≤L1 / H≤28.

4. The battery according to claim 3, characterized in that, Along the second direction, the distance between the second end and the through hole is b, which satisfies: 0.4mm≤b≤4.5mm.

5. The battery according to claim 2, characterized in that, It also includes an insulating element for insulating the tab and the housing, the insulating element being disposed on the tab and / or the housing, satisfying: 4≤L1 / H≤30.

6. The battery according to claim 5, characterized in that, The electrode lug includes a first connecting portion, a welding portion, and an extension portion connected in sequence. The welding portion is welded to the electrode post to form a first weld mark. The side surface of the welding portion facing the electrode post is a first surface, and the side surface of the welding portion away from the electrode post is a second surface. The end of the first connecting portion away from the welding portion is a first end, and the end of the extension portion away from the welding portion is a second end. The extension portion has a third surface and a fourth surface. The third surface is connected to the first surface, and the fourth surface is connected to the second surface. The insulating element is connected to the third surface, or the insulating element is connected to the third surface and connected to the fourth surface, or the insulating element is connected to the third surface, connected to the fourth surface, and connected to the second surface.

7. The battery according to claim 5, characterized in that, The electrode post has a fifth surface facing the battery cell, the first sidewall has a sixth surface facing the fifth surface, and at least a portion of the insulator is located between the sixth surface and the fifth surface.

8. The battery according to claim 7, characterized in that, Along the first direction, the end of the insulating member closest to the cell body is the first insulating end, and the end of the through hole closest to the cell body is the first orifice end; along the first direction, the distance between the first insulating end and the pole post is greater than the distance between the second end and the pole post, and the distance between the first orifice end and the pole post is greater than the distance between the first insulating end and the pole post.

9. The battery according to claim 7, characterized in that, Along the first direction, the end of the insulating member closest to the cell body is the first insulating end, and the end of the through hole closest to the cell body is the first orifice end; along the first direction, the distance between the first insulating end and the electrode post is greater than the distance between the first orifice end and the electrode post.

10. The battery according to claim 2, characterized in that, The electrode tab includes a first connecting part, a welding part, and an extension part connected in sequence. The welding part is welded to the electrode post to form a first weld mark. The end of the first connecting part away from the welding part is the first end, and the end of the extension part away from the welding part is the second end. The extension part has a staggered structure, which includes multiple electrode tab pieces stacked together. At least two of the multiple electrode tab pieces have different lengths. In the staggered structure of the extension, the length difference between the longest and shortest tabs is a, and the extension extends along the second direction; along the second direction, the distance between the second end and the through hole is b, satisfying: 0.1≤a / b≤16.

11. The battery according to claim 2, characterized in that, Along the extended direction of the flattened tab, the distance between the second end and the first solder mark is L2, which satisfies: 0.2mm≤L2≤5.5mm.

12. The battery according to claim 2, characterized in that, The electrode tab includes a first connecting part, a welding part, and an extension part connected in sequence. The welding part is welded to the electrode post to form a first weld mark. The end of the first connecting part away from the welding part is the first end, and the end of the extension part away from the welding part is the second end. Wherein, along the extension direction of the flattened tab, the distance between the second end and the first solder mark is L2, the size of the first solder mark is L3, and the size of the tab is L4, satisfying: 0.04≤(L2+L3) / L4≤0.

8.

13. The battery according to claim 12, characterized in that, 0.02≤L2 / L3≤3.

5.

14. The battery according to claim 2, characterized in that, The electrode lug includes a first connecting part, a first bending part, a welding part, and an extension part connected in sequence. The welding part is welded to the electrode post to form a first weld mark. The end of the first connecting part away from the welding part is the first end, and the end of the extension part away from the welding part is the second end. The first bending part has a first opening groove, and the bottom of the first opening groove has a first marking point. Wherein, along the extension direction of the flattened tab, the minimum distance between the first marking point and the first solder mark is L5, which satisfies: 0.5mm≤L5≤4mm.

15. The battery according to claim 14, characterized in that, The electrode tab further includes a second bend, and the first connecting portion is connected to the first bend through the second bend. The second bend forms a second opening groove; the bottom of the second opening groove has a second marking point. Wherein, along the extension direction of the flattened tab, the distance between the first marking point and the second marking point is L6, which satisfies: 1.5mm≤L6≤11mm.

16. The battery according to claim 15, characterized in that, Along the first direction, the minimum distance from the second mark point to the side of the cell body near the through hole is L7, which satisfies: 0.5mm≤L7≤5mm.

17. The battery according to claim 2, characterized in that, The surface of the electrode tab is provided with reinforcing ribs; along the extension direction of the flattened electrode tab, the distance between the reinforcing ribs and the first solder mark is L8, which satisfies: 0.3mm≤L8≤4.5mm.

18. The battery according to claim 2, characterized in that, The electrode tab is provided with a reinforcing rib; along the extension direction of the flattened electrode tab, the distance between the reinforcing rib and the first end is L9, which satisfies: 1.5mm≤L9≤6mm.

19. The battery according to claim 14, characterized in that, The electrode lug is provided with a reinforcing rib, which is located on the outer side of the first bend.

20. The battery according to claim 2, characterized in that, The electrode tab includes multiple electrode tab pieces, which are pre-fixed by a second solder mark.

21. The battery according to claim 20, characterized in that, Along the extended direction of the flattened tab, the minimum distance between the second solder mark and the first end is L. 10 Satisfying: 0.1 ≤ (L1 - L) 10 ) / L1≤0.

7.

22. The battery according to claim 2, characterized in that, The electrode tab is equipped with a fuse; Wherein, the second direction is perpendicular to the first auxiliary plane, and along the second direction, the electrode forms a first orthographic projection on the first auxiliary plane, the area of ​​the first orthographic projection is S1, and the fuse forms a second orthographic projection on the first auxiliary plane, the area of ​​the second orthographic projection on the first auxiliary plane is S2; satisfying: 0.3≤S2 / S1≤0.

7.

23. The battery according to claim 22, characterized in that, Along the first direction, the distance between the fuse and the first solder mark is L. 12 The distance between the fuse and the first end is L. 13 Satisfying: 1mm≤L 12 ≤10mm, and / or, 1.5mm≤L 13 ≤10mm.

24. The battery according to claim 2, characterized in that, A transition angle is provided between the electrode tab and the battery cell body. The transition angle is a rounded corner with a radius of r, which satisfies the condition: 0.8mm≤r≤8.5mm.

25. The battery according to claim 2, characterized in that, The electrode sheet is provided with insulating adhesive on the side near the electrode tab; Wherein, along the first direction, the size of the insulating adhesive is K1, and the size of the battery cell is K2, satisfying: 0.005≤K1 / K2≤0.

05.

26. The battery according to claim 2, characterized in that, Along the third direction, the size of the electrode tab is K3, and the size of the through hole is K4, satisfying: 0.3≤K3 / K4≤0.

8.

27. The battery according to claim 2, characterized in that, Along the third direction, the size of the electrode tab is K3, and the size of the battery cell is K5, satisfying: 0.1≤K3 / K5≤0.

45.

28. The battery according to claim 2, characterized in that, Along the third direction, the distance between the tab and the end of the cell body is K6, which satisfies: 10mm≤K6≤60mm.

29. The battery according to claim 2, characterized in that, The electrode tab has a staggered structure, which includes multiple electrode tab pieces stacked together. Wherein, the width of the electrode tab is K7, and the width of the electrode lug is K8, satisfying: 0.6≤K7 / K8≤0.

9.

30. The battery according to claim 2, characterized in that, The surface of the electrode tab is adhered with insulating tape; the insulating tape includes a first part, a second part and a third part connected in sequence, the first part is provided with adhesive backing and is adhered to the surface of the electrode tab with adhesive backing, the second part is not provided with adhesive backing, and the third part is provided with adhesive backing and is adhered to the surface of the cell body with adhesive backing; the projections of the second part and the first end on the large surface of the cell body at least partially overlap.

31. The battery according to claim 1, characterized in that, The lead-out portion includes a tab and an adapter piece. The first end and the second end are disposed on the tab, and the adapter piece is disposed between the tab and the post. The adapter piece and the post are welded together to form a first solder mark. The thickness of the adapter piece is d, which satisfies the condition: 0.5mm≤d≤4mm.

32. The battery according to claim 1, characterized in that, The lead-out portion includes a tab and an adapter piece. The adapter piece is a soldering tab and is connected to the side of the tab away from the pole. The tab and the pole are soldered together through the soldering tab. The following condition is satisfied: 0.1mm≤d≤0.5mm.

33. The battery according to claim 32, characterized in that, The electrode lug includes a first connecting part, a first bending part, a welding part, and an extension part connected in sequence. The welding part is welded to the electrode post to form a first weld mark. The end of the first connecting part away from the welding part is the first end, and the end of the extension part away from the welding part is the second end. The first bending part has a first opening groove, and the bottom of the first opening groove has a first marking point. Wherein, along the extension direction of the flattened electrode tab, the minimum distance between the first marking point and the flux sheet is L. 14 Satisfying: 0.5mm≤L 14 ≤5mm.

34. The battery according to claim 1, characterized in that, The lead-out portion includes a first connecting portion, a welding portion, and an extension portion connected in sequence. The end of the first connecting portion away from the welding portion is the first end, and the end of the extension portion away from the welding portion is the second end. The welding portion is welded to the electrode post to form a first solder mark, and the electrode post has a fifth surface facing the battery cell. Wherein, the area of ​​the first solder mark is S3, and the area of ​​the fifth surface is S4, satisfying: 0.1≤S3 / S4≤0.

6.

35. The battery according to claim 1, characterized in that, The lead-out portion includes a first connecting portion, a welding portion, and an extension portion connected in sequence. The end of the first connecting portion away from the welding portion is the first end, and the end of the extension portion away from the welding portion is the second end. The welding portion is welded to the electrode post to form the first solder mark, and the electrode post has a fifth surface facing the battery cell. The cross-sectional area of ​​the through hole perpendicular to the first direction is S5, and the area of ​​the fifth surface is S4, satisfying: 0.4≤S5 / S4≤0.

85.

36. The battery according to claim 1, characterized in that, The first sidewall facing the battery cell has a first groove, and the through hole is provided through the bottom of the first groove along the first direction.

37. The battery according to claim 1, characterized in that, The first sidewall has a second groove on the side opposite to the battery cell, and the through hole is provided through the bottom of the second groove along the first direction. At least a portion of the electrode post is provided in the second groove.

38. The battery according to claim 1, characterized in that, The number of poles is two, and the first sidewall has a sixth surface facing away from the battery cell. Both poles are located on the side of the sixth surface facing away from the battery cell.

39. The battery according to claim 38, characterized in that, Along the third direction, the distance between the two pole pieces is L. 15 Satisfying: 2mm≤L 15 ≤26mm.

40. A battery pack, characterized in that, The battery comprises at least two batteries according to any one of claims 1-39, and further comprises a conductive busbar, wherein two adjacent batteries are electrically connected through the conductive busbar, and the conductive busbar is fixed to the terminal post by a third solder joint; the distance between the third solder joint and the first solder joint along the first direction is L. 16 Satisfying: 2.5mm≤L 16 ≤8.5mm.

41. The battery pack according to claim 40, characterized in that, Along the first direction, the third solder mark and the first solder mark are misaligned.

Images