Battery monomer, battery and electric device

Abstract

The utility model relates to a battery monomer which comprises a shell, a battery core assembly and a pole, the at least two second connecting parts of the pole are arranged at intervals along the width direction of the first wall, namely the thickness direction of the shell, and the at least two groups of tabs in the battery core assembly respectively correspond to the positions of the at least two second connecting parts, so that the at least two groups of tabs can be directly welded with the tab welding surfaces of the at least two second connecting parts respectively; therefore, an adapter plate is omitted, and the welding positions between the pole and the tabs are reduced. Moreover, the surfaces of the first welding part and the second welding part of the welding printing structure are parts of the spherical surfaces, and are fully contacted with the tab and the second connecting part, so that the resistance value of the welding position is relatively small. Therefore, the single battery can reduce the resistance value of each welding position while reducing the welding positions, so that the internal resistance of the single battery can be remarkably reduced. In addition, the utility model also provides a battery and an electric device.

Description

Technical Field

[0001] This utility model relates to the technical field, and in particular to a battery cell, a battery, and an electrical device. Background Technology

[0002] Lithium-ion batteries generally consist of a casing, cell assembly, and top cover assembly. Before installing the cell assembly into the casing, it needs to be assembled with the top cover assembly. Currently, adapters are typically used to electrically connect the tabs of the cell assembly to the terminals of the top cover assembly. The adapters and tabs, as well as the tabs and terminals, are generally welded using methods such as laser welding and ultrasonic welding. The resistance at the weld joints is relatively high, leading to an increase in the overall internal resistance of the battery. Therefore, the battery generates significant heat during actual operation, reducing its energy efficiency. Utility Model Content

[0003] Therefore, it is necessary to provide a battery cell, battery, and power device that can reduce internal resistance to address the above problems.

[0004] On one hand, this application provides a single battery cell, comprising:

[0005] A single battery cell, comprising:

[0006] The outer casing includes a first wall, the first wall being provided with a first through hole;

[0007] A battery cell assembly, housed within the housing, the battery cell assembly including at least two sets of electrodes; and

[0008] The pole includes a first connecting part and at least two second connecting parts. The first connecting part is located on a first side in the thickness direction of the first wall, and the at least two second connecting parts are spaced apart along the width direction of the first wall. Each second connecting part is connected to the first connecting part and extends from the first through hole to a second side in the thickness direction of the first wall.

[0009] Wherein, at least two second connecting portions are correspondingly provided with at least two sets of electrodes, and each set of electrodes is connected to the electrode welding surface of the corresponding second connecting portion by at least one solder mark structure. Each solder mark structure includes a first welding portion extending into the electrode and a second welding portion extending into the second connecting portion. The first welding portion and the second welding portion together constitute at least a spherical shape.

[0010] In one embodiment, the first wall is a cover plate, the outer casing includes the cover plate and a housing, the battery cell assembly is housed within the housing, and the cover plate is sealed at an opening in the housing; and / or,

[0011] The battery cell assembly includes at least two battery cells arranged side by side along the width direction of the first wall, each battery cell having a set of tabs extending out, and the tabs of at least two battery cells being arranged in a one-to-one correspondence with at least two second connection portions.

[0012] In one embodiment, the center of the sphere containing the first welded portion and the second welded portion is located at the interface between the second connecting portion and the electrode tab.

[0013] In one embodiment, the second weld portion is hemispherical.

[0014] In one embodiment, there is only one weld mark structure between the electrode tab and the electrode tab welding surface of the corresponding second connection part, and the maximum cross-sectional area of ​​the second welding part in the thickness direction of the second connection part is less than or equal to 0.32 times the area of ​​the electrode tab welding surface.

[0015] In one embodiment, a plurality of weld marks are provided between the electrode tab and the electrode tab welding surface of the corresponding second connecting part, wherein the maximum cross-sectional area of ​​each second welding part in the thickness direction of the second connecting part is less than or equal to 2πmm. 2 .

[0016] In one embodiment, a plurality of solder marks are formed between each set of tabs and the corresponding second connection portion, and the plurality of solder marks are spaced apart from each other.

[0017] In one embodiment, a tab pad is also included, the tab pad being located on the side of the tab away from the tab welding surface and being welded to the tab.

[0018] In one embodiment, in the first wall thickness direction, the projection of the first connecting portion does not coincide with the projection of the first through hole, and the projection of the second connecting portion covers the projection of the first through hole.

[0019] In one embodiment, each of the second connecting portions extends from a first side of the first wall to a second side of the first wall to form a connecting sub-portion, and the electrode welding surface is located on the surface of the connecting sub-portion extending beyond the second side of the cover plate.

[0020] In one embodiment, a first insulating member is further included, the first insulating member including a first insulating portion and a second insulating portion, at least a portion of the first insulating portion being disposed between the first connecting portion and the first wall, the second insulating portion covering at least a portion of the surface of the second connecting portion away from the first wall, and the second insulating portion having a clearance hole exposing a portion of the surface of the second connecting portion.

[0021] In one embodiment, a groove is provided at the position of the second connecting part corresponding to the clearance hole, and the groove is located on the back side of the connecting part.

[0022] In one embodiment, the area of ​​the clearance hole on a plane parallel to the first wall is larger than the area of ​​the groove opening.

[0023] In one embodiment, the minimum distance between the edge of the groove away from the first wall side and the edge of the second insulating portion is greater than 0.

[0024] In one embodiment, a sealing element is provided inside the clearance hole, and the sealing element blocks the clearance hole.

[0025] In one embodiment, the pole post further includes at least two transition portions, each of the at least two transition portions being disposed in a one-to-one correspondence with at least two second connecting portions, and each second connecting portion being electrically connected to the first connecting portion through the corresponding transition portion.

[0026] In one embodiment, a fusible portion is formed on the transition portion, the flow area of ​​the fusible portion is smaller than the flow area of ​​the first connecting portion, and the flow area of ​​the fusible portion is smaller than the flow area of ​​the second connecting portion.

[0027] In one embodiment, the pole is integrally stamped.

[0028] Compared with the prior art, this application has at least the following advantages:

[0029] In the aforementioned battery cell, at least two second connecting portions of the terminal are spaced apart along the width direction of the first wall, i.e., the thickness direction of the outer casing. At least two sets of tabs in the cell assembly correspond to the positions of at least two second connecting portions, allowing for direct welding of the tabs to the welding surfaces of the at least two second connecting portions. This eliminates the need for adapter plates and reduces the number of welding points between the terminal and the tabs. Furthermore, since the surfaces of the first and second welding portions of the solder joint are both part of a sphere, they make sufficient contact with the tabs and second connecting portions, resulting in lower resistance at the welding points. Simultaneously, the second connecting portions have portions not covered by insulation, which can be used for electrical connection during pressure welding, preventing the terminal from melting during pressure welding. Therefore, the aforementioned battery cell can reduce the resistance at each welding point while reducing the number of welding points, thus significantly reducing the internal resistance of the battery cell.

[0030] On the other hand, this application provides a battery comprising a plurality of battery cells as described in any of the above embodiments, wherein the plurality of battery cells are electrically connected by an electrical connector, and the electrical connector is connected to the first connection portion.

[0031] In addition, this application also provides an electrical device, including a battery cell as described in any one of the above embodiments or a battery as described in the above embodiments. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is an exploded view of a single battery cell in one embodiment of the present invention;

[0034] Figure 2 for Figure 1 A cross-sectional view of the battery cell shown;

[0035] Figure 3 for Figure 1 A top view of the first wall of the outer casing of the battery cell shown;

[0036] Figure 4 for Figure 3 An exploded view of the first wall of the outer shell shown;

[0037] Figure 5 for Figure 3 The first wall of the shell shown is in cross-section along AA;

[0038] Figure 6 for Figure 1 The diagram shows the structural diagram of the electrode in a single battery cell;

[0039] Figure 7 for Figure 6 A cross-sectional view of the pole shown;

[0040] Figure 8 for Figure 1 A schematic diagram of the electrode tabs and terminals of the battery cell assembly after welding.

[0041] Figure 9 for Figure 8 A sectional view of the area where the solder joint structure is shown.

[0042] Figure 10 This is a schematic diagram illustrating a scenario where the tab and the pole are welded together in one embodiment.

[0043] Figure 11 This is a schematic diagram of a scenario where the tab and the pole are welded together in another embodiment. Detailed Implementation

[0044] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0045] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0047] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0048] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0049] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0050] This utility model discloses an electrical device, a battery, and a battery cell. The electrical device includes the battery or the battery cell and is capable of providing electrical energy. The electrical device can be a vehicle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, power tool, energy storage device, amusement equipment, elevator, and lifting equipment, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, or electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.; energy storage devices can be energy storage walls, base station energy storage, container energy storage, etc.; amusement equipment can be a carousel, a drop tower, etc.

[0051] The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended vehicles, etc. For new energy vehicles, the aforementioned battery can serve as a driving power source, thereby replacing fossil fuels to provide propulsion. This application does not impose any special restrictions on the aforementioned electrical devices.

[0052] The aforementioned battery can be a battery pack or a battery module. When the battery is a battery pack, the battery pack specifically includes a battery management system (BMS) and multiple battery cells. Multiple battery cells can be electrically connected in series, parallel, or a combination of series and parallel connections, and communicate with the battery management system, which controls and monitors the operating status of each battery cell. Alternatively, multiple battery cells can first be combined with a module management system to form a battery module, and then these battery modules can be electrically connected in series, parallel, or a combination of series and parallel connections to form a battery pack together with the battery management system.

[0053] Multiple battery cells can be mounted on supporting structures such as housings, frames, and brackets. The individual battery cells and the battery management system can be electrically connected via electrical connectors, such as busbars. The battery cells can be lithium-ion, sodium-ion, or magnesium-ion batteries, and their external contours can be cylindrical, flat, cuboid, or other shapes, but are not limited to these. Specifically, in this embodiment, the battery cell is a lithium-ion square battery.

[0054] Please see Figure 1 and Figure 2 In one embodiment of the present invention, the battery cell 10 includes a housing 100, a cell assembly 200, and a terminal post 300.

[0055] The outer casing 100 has a hollow structure, and its interior has a receiving space for accommodating the battery cell assembly 200, electrolyte, and other components. The outer casing 100 includes a first wall, and the first wall is provided with a first through hole 121 (see...). Figure 4 This is used to install the terminal post 300. Specifically, in this embodiment, the outer casing 100 includes a casing 110 and a cover plate 120. The first wall is the cover plate 120, that is, the first through hole 121 is formed on the cover plate 120. At least one end of the casing 110 is provided with an opening, through which the battery cell assembly 200 can be installed into the casing 110. The cover plate 120 is sealed at the opening of the casing 120, thereby forming a relatively closed environment inside the outer casing 100 to isolate the battery cell assembly 200 from the external environment.

[0056] The cover plate 120 can be formed from a material with high mechanical strength, such as aluminum, aluminum alloy, or steel. Since the battery cell 10 in this embodiment is a square battery, the outer contour of the casing 110 is cuboid, its opening is rectangular, and the cover plate 120 is also approximately rectangular. The cover plate 120 has a first side and a second side arranged opposite to each other along its thickness direction. The second side is the inner side, which refers to the surface of the cover plate 120 facing the inside of the casing 110 when covering the opening of the casing 110, while the first side is the outer side, which refers to the surface of the cover plate 120 facing away from the inside of the casing 110.

[0057] It should be noted that in other embodiments, the first wall may also be one of the side walls of the housing 110 and integrally formed with the housing 110.

[0058] The cell assembly 200 is the core component of the battery cell 10. To fit the shape of the casing 200, the cell assembly 200 in this embodiment is approximately rectangular. The cell assembly 200 generally includes two or more sets of tabs 211. Specifically, the cell assembly 200 includes at least two cells 210 arranged side-by-side along the width direction of the first wall, i.e., the thickness direction of the casing 100, with each set of cells 210 extending out tabs 211. Each set of cells 210 may contain one or more cells 210. The cells 210 can be formed by winding or stacking positive electrode plates, negative electrode plates, and a separator that acts as an insulator between the negative and positive electrode plates. The wound cells 210 can be pressed into a flat shape with rounded curved surfaces on both sides. The tabs 211 of each cell 210 are divided into a positive tab (not shown) and a negative tab (not shown), which are led out from the positive and negative electrode plates, respectively.

[0059] The positive and negative tabs can be located at the same end of the cell 210 or at opposite ends of the cell 210. Specifically, in this embodiment, the cell assembly 200 includes two cells 210, and the positive and negative tabs of each cell 210 are located at the same end of the cell 210 and spaced apart along the width direction of the cell assembly 200, i.e., the width direction of the outer casing 100. Therefore, one end of the cell assembly 200 has four sets of tabs 211, two sets of which are negative tabs spaced apart along the thickness direction of the outer casing 100, and the other two sets are positive tabs spaced apart along the thickness direction of the outer casing 100. The two sets of negative tabs and the two sets of positive tabs are spaced apart along the width direction of the outer casing 100.

[0060] Specifically, the width direction of the outer casing 10 refers to... Figure 2 The direction shown is perpendicular to the plane of the drawing, while the thickness direction of the outer shell 10 refers to the left and right direction.

[0061] Please refer to the following: Figure 3 and Figure 4The terminal post 300 is installed on the first wall of the housing 100 and is used for electrical connection with the tab 211 of the cell assembly 200, thereby serving as the positive or negative terminal of the battery cell 10. Since the positive and negative tabs of the cell assembly 200 are located on the same side in this application, two mutually spaced first through holes 121 are provided along the length of the first wall, and two terminal posts 300 are correspondingly provided. The two terminal posts 300 are used for welding to the positive and negative tabs of the cell assembly 200, respectively. Of course, if the positive and negative tabs are located at opposite ends of the cell assembly 200, only one terminal post 300 needs to be provided on each first wall. In this case, a second through hole (not shown) needs to be opened on the second wall of the housing 100 opposite to the first wall, and another terminal post 300 needs to be provided thereon.

[0062] Please refer to the following: Figure 5 , Figure 6 and Figure 7 The terminal post 300 includes a first connecting portion 310 and a second connecting portion 320. At least two second connecting portions 320 are provided, and these at least two second connecting portions 320 are spaced apart along the width direction of the first wall, i.e., the width direction of the cover plate 120. The first connecting portion 310 is used to connect an electrical connector (not shown), and the second connecting portion 320 is used to connect a tab 211. Optionally, the first connecting portion 310 and the second connecting portion 320 are integrally formed by stamping sheet metal. When multiple battery cells 10 are connected by electrical connectors, the electrical connectors can be connected to the first connecting portion 310 by welding or other methods. The aforementioned electrical connectors can be busbars or other terminal posts 300 of battery cells 10.

[0063] Specifically, in this embodiment, in the first wall thickness direction, the projection of the first connecting part 310 does not coincide with the projection of the first through hole 121, and the projection of the second connecting part 320 covers the projection of the first through hole 121.

[0064] In other words, the positions of the first connecting part 310 and the second connecting part 320 are staggered, and the first connecting part 310 is also staggered from the first through hole 121. This prevents the first through hole 121 from being too large and affecting the strength of the cover plate 120. The first connecting part 310 is fixed to the cover plate 120, which can enhance the structural strength. At the same time, when the electrical connector is welded to the first connecting part 310, the welding laser can be prevented from penetrating to the second connecting part 320 and causing adverse effects on the sealing structure between the second connecting part 320 and the first through hole 121, such as the sealing ring (not shown in the figure), thus reducing the risk of the sealing ring melting and cracking.

[0065] Furthermore, the first connecting portion 310 is mounted on the first side (i.e., the outer side) of the first wall of the housing 100, and at least two second connecting portions 320 extend from the first through hole 121 toward the second side (i.e., the inner side) of the first wall. Each second connecting portion 320 has a tab welding surface 321 for welding to the connecting tab 211.

[0066] The battery cell 10 generally also includes a first insulating member 600, which includes a first insulating portion 610 and a second insulating portion 620. Optionally, the first insulating portion 610 and the second insulating portion 620 can be connected together. At least a portion of the first insulating portion 610 is disposed between the first connecting portion 310 and the first wall, and the second insulating portion 620 covers at least a portion of the surface of the second connecting portion away from the first wall. The first insulating portion 610 can form insulation between the first connecting portion 310 and the first wall, and the second insulating portion 620 can protect the second connecting portion 320 from corrosion.

[0067] Please refer to the following: Figure 8 and Figure 9 In the battery cell assembly 200, at least two sets of tabs 211 are correspondingly provided with at least two second connection parts 320, and each set of tabs 211 and the corresponding second connection part 320 are welded by a soldering structure 400.

[0068] Specifically, in this embodiment, multiple solder marks 400 are formed between each set of tabs 211 and the corresponding second connecting portion 320, and the multiple solder marks 400 are spaced apart from each other. This improves the reliability of the welding between the tabs 211 and the second connecting portion 320. Of course, only one solder mark 400 may be formed between each set of tabs 211 and the corresponding second connecting portion 320.

[0069] Typically, the negative electrode tab and the electrode post 110 welded to it are made of copper, which has a high melting point. Multiple solder marks 400 are usually provided between the negative electrode tab and the negative electrode post 110. The positive electrode tab and the electrode post 110 welded to it are made of aluminum, which has a lower melting point. Only one solder mark 400 is usually provided between the positive electrode tab and the positive electrode post 110.

[0070] Furthermore, each solder joint structure 400 includes a first solder portion 410 extending into the tab 211 and a second solder portion 420 extending into the second connection portion 320, wherein the first solder portion 410 and the second solder portion 420 together constitute at least a portion of a sphere. That is, the surfaces of the first solder portion 410 and the second solder portion 420 are both part of a sphere.

[0071] It should be noted that the solder mark structure 400 is formed naturally during the welding process. Its spherical outline can be a standard sphere or approximately spherical. Therefore, the surfaces of the first welding part 410 and the second welding part 420 can also be non-standard spherical surfaces, and their surfaces may have burrs or areas with uneven transitions.

[0072] The spherical solder structure 400 makes full contact with the tab 211 and the second connection portion 320, resulting in a lower resistance at the soldering position. Furthermore, since at least two sets of tabs 211 of the cell assembly 20 correspond to at least two positions of the second connection portion 320, the at least two sets of tabs 211 can be directly soldered to the tab soldering surfaces 321 of the at least two second connection portions 320, thereby eliminating the need for adapters and reducing the number of soldering positions between the terminal post 200 and the tabs 211. Therefore, the aforementioned battery cell 10 can reduce the resistance at each soldering position while reducing the number of soldering positions, thus significantly reducing internal resistance.

[0073] The aforementioned solder mark structure 400 can be formed by pressure welding. Specifically, before welding the tab 211, bumps 322 are provided on the tab welding surface 321. The melting of the bumps 322 forms the solder mark structure 400 connecting the tab 211 and the tab welding surface 321. Each bump 322 can form a solder mark structure 400 after melting, and multiple bumps 322 can form multiple solder mark structures 400. Figure 7 The image shows the electrode post 300 before the electrode tab 211 is welded, with protrusions 322 on its electrode tab welding surface 321; as shown Figure 8 As shown, after the tab 211 is welded, the bump 322 melts and forms a solder mark structure 400. It can be seen that the bump 322 does not exist on the terminal post 300 of the assembled battery cell 10.

[0074] Please see Figure 10 or Figure 11 The general process of pressure welding is as follows: the first electrode 20 holds the tab 211 to be welded from one side, and the second electrode 30 holds the pole post 300 from the other side, thereby clamping the pole post 300 and the tab 211 to be welded between the first electrode 20 and the second electrode 30; the first electrode 20 and the second electrode 30 apply pressure to the tab 211 and the pole post 300 from both sides respectively; the first electrode 20 and the second electrode 30 are energized, so that the joint between the protrusion 322 and the tab 211 heats up; the protrusion 322 melts under the dual action of high temperature and pressure, and forms a weld mark structure 400.

[0075] To facilitate welding the tab 211 to the tab welding surface 321, in this embodiment, each second connecting portion 320 extends from the first side of the cover plate 120 to the second side of the cover plate 120 to form a connecting sub-portion 323. The tab welding surface 321 is located on the surface of the connecting sub-portion 323 that extends beyond the second side of the first wall. Therefore, the tab welding surface 321 also extends beyond the second side of the first wall and is not obstructed by the sidewall of the first through hole 121. Thus, there is more space and the operation is more convenient when welding the tab 211 to the tab welding surface 321.

[0076] Furthermore, a groove 324 is provided on one side of the second connecting portion 323 opposite to the sub-connecting portion 323. The groove 324 can be obtained by stretching the second connecting portion 323 while forming the sub-connecting portion 323, which can save materials and reduce weight.

[0077] Of course, in other embodiments, the connecting portion 323 of the second connecting portion 320 may not extend beyond the second side of the first wall. That is, the electrode welding surface 321 is located inside the first through hole 121. In this case, the electrode 211 needs to be inserted into the first through hole 121 before it can be welded to the electrode welding surface 321.

[0078] Please refer to it again. Figure 9 In this embodiment, the center of the sphere containing the first welding portion 410 and the second welding portion 420 is located at the interface between the second connecting portion 320 and the tab 211. It can be seen that the section of the solder mark structure 400 with the largest area along the thickness direction of the second connecting portion 320 is located at the interface between the second connecting portion 320 and the tab 211, thereby increasing the current-passing area between the second connecting portion 320 and the tab 211 and improving their conductivity.

[0079] More specifically, in this embodiment, the second weld portion 420 is hemispherical. The shape of the first weld portion 410 is related to the thickness of the tab 211.

[0080] In this embodiment, when only one solder joint structure 400 is provided between the tab 211 and the second connecting portion 320, the maximum cross-sectional area of ​​the second welding portion 420 in the thickness direction of the second connecting portion 320 is less than or equal to 0.32 times the area of ​​the tab welding surface 321. The cross-sectional area of ​​the second welding portion 420 in the thickness direction of the second connecting portion 320 is... Figure 9 The cross-sectional area of ​​the second welded portion 420 in the cross-section shown. At this time, the maximum cross-sectional area of ​​the second welded portion 420 in the thickness direction of the second connecting portion 320 is 1 / 2 of the cross-sectional area of ​​the second welded portion 420 on the electrode welding surface 420. This can prevent the edge of the second welded portion 420 from being too close to the edge of the electrode welding surface 321, thereby avoiding problems such as bursting or breakage at the edge of the electrode welding surface 321 during the welding process.

[0081] In the case where multiple solder joints 400 are provided between the tab 211 and the second connecting portion 320, the maximum cross-sectional area of ​​each second welding portion 420 in the thickness direction of the second connecting portion 320 is less than or equal to 2πmm. 2 This ensures that multiple solder marks can be distributed on the electrode welding surface, avoiding interference between the multiple solder marks.

[0082] In addition, in this embodiment, the battery cell 10 also includes a tab pad 500, which is located on the side of the tab 211 away from the tab welding surface 321 and is welded to the tab 211.

[0083] The thickness of the tab pad 500 is generally greater than the thickness of the tab 211. The thickness of the tab 211 is generally 5μm to 20μm, while the thickness of the tab pad 500 is generally 0.2mm to 1mm. During pressure welding, the tab pad 500 separates the tab 211 from the electrode, thus preventing the tab 211 from sticking to the first electrode 20 during welding, which would affect the welding effect. This is especially true for the positive tab, as its material is aluminum, which has a lower melting point than copper, making it more prone to melting and sticking to the first electrode 20 during welding. Therefore, an aluminum tab pad 500 is generally placed between the positive tab and the electrode. A tab pad 500 may or may not be placed between the negative tab and the electrode.

[0084] Because the tab pad 500 is relatively thick, the side of the aluminum tab pad 500 facing the first electrode 20 is less likely to melt during welding, thus preventing adhesion to the first electrode 20. However, the side of the aluminum tab pad 500 facing the tab 211 melts during welding and eventually connects to the tab 211 and the electrode post 300, thus strengthening the connection between the tab 211 and the electrode post 300 and improving conductivity.

[0085] Please refer to it again. Figure 6 and Figure 7 In this embodiment, the pole post 300 further includes at least two transition portions 330, and the at least two transition portions 330 are respectively arranged in a one-to-one correspondence with at least two second connecting portions 320. Each second connecting portion 320 is electrically connected to the first connecting portion 310 through the corresponding transition portion 330.

[0086] The transition portion 330 serves as a transitional connection between the first connecting portion 310 and the second connecting portion 320. The transition portion 330 is stretchable and forms a height difference between the first connecting portion 310 and the second connecting portion 320 along the thickness direction of the electrode post 300 to facilitate installation. During the operation of the battery cell 10, current is transmitted between the first connecting portion 310 and the second connecting portion 320 through the transition portion 330.

[0087] During pressure welding, since the second electrode 30 is typically held against the surface of the first connecting portion 310, the current generated when the first electrode 20 and the second electrode 30 are energized will also flow through the transition portion 330. Moreover, since the current required for pressure welding is larger than the current generated by the normal operation of the battery cell 10, the transition portion 330 is at risk of melting during the welding process. Strengthening the transition portion 330 would increase material and manufacturing costs and may also affect normal use.

[0088] To avoid the above problems, please refer to the following again. Figure 5 In this embodiment, the second insulating portion 620 is provided with a clearance hole 621 that exposes a portion of the surface of the second connecting portion 320. When the tab 211 is pressure welded, the first electrode 20 can pass through the clearance hole 621 to abut against and electrically connect with the second connecting portion 320, thereby achieving conductive contact with the pole post 300.

[0089] Furthermore, the position of the clearance hole 621 corresponds to the position of the groove 324. Therefore, the first electrode 20 can pass through the clearance hole 621 and be inserted into the groove 324, thereby achieving conductive contact with the electrode post 300. The groove 324 can effectively limit the first electrode 20, thereby ensuring that the first electrode 20 remains stable during the welding process.

[0090] Optionally, the second insulating portion 620 may only cover a portion of the non-recessed area of ​​the second connecting portion 320 away from the first wall 120 (not shown), so that during pressure welding, a portion of the first electrode 20 can directly abut against the surface of the part not covered by the insulating component, resulting in a larger contact area. Specifically, the area of ​​the clearance hole 621 on the plane parallel to the first wall 120 may be larger than the area of ​​the groove opening, so that a portion of the surface is exposed except for the groove opening; alternatively, the minimum distance between the edge of the groove away from the edge of the second insulating portion 620 and the edge of the groove away from the first wall may be greater than 0, so that there is a ring of exposed portion around the groove opening.

[0091] Furthermore, in this embodiment, to avoid risks such as overheating, thermal runaway, and explosion during actual use, a fusible link 340 is formed on the transition portion 330. The current-carrying area of ​​the fusible link 340 is smaller than that of the first connecting portion 310 and smaller than that of the second connecting portion 320. The smaller the current-carrying area, the greater the resistance and the greater the heat generated when current flows through it. Optionally, the fusible link 340 is disposed on the positive electrode post, which is usually made of aluminum, which has a lower melting point and is easier to melt; the negative electrode post is usually made of copper, which has a higher melting point and requires more heat to melt, so the negative electrode post usually does not have a fusible link. Of course, in some cases, the negative electrode post may have a fusible link.

[0092] Specifically, the current-passing area can be reduced by forming a hollow structure or thinning the structure on the transition portion 330, thereby obtaining the fuse portion 340. When the battery cell 10 malfunctions, the fuse portion 340 between the first connection portion 310 and the second connection portion 320 will easily melt and break the circuit, thus ensuring safety. In other words, the fuse portion 340 can act as a safety structure.

[0093] At this time, the current generated after the first electrode 20 and the second electrode 30 are energized can flow along the path from the second electrode 30, the second connecting part 320, the tab 211 to the first electrode 20 (or from the first electrode 20, the tab 211, the second connecting part 320 to the second electrode 30), and will not flow through the fuse part 340, thereby effectively preventing the fuse part 340 from melting.

[0094] Furthermore, in this embodiment, a sealing element (not shown) is provided inside the clearance hole 621 to seal the clearance hole 621. After the sealing element seals the clearance hole 621, it can prevent impurities such as moisture and dust from contacting the second connection part 320 through the clearance hole 621 during the subsequent use of the battery cell 10, thereby preventing internal corrosion of the terminal post 300 and avoiding problems such as short circuits.

[0095] In the aforementioned battery cell 10, at least two second connecting portions 320 of the terminal post 300 are spaced apart along the width direction of the first wall, i.e., the thickness direction of the outer casing 100. In the cell assembly 200, at least two sets of tabs 211 correspond to the positions of at least two second connecting portions 320, respectively. Therefore, at least two sets of tabs 211 can be directly welded to the tab welding surfaces 321 of at least two second connecting portions 320, thereby eliminating the need for adapter plates and reducing the number of welding positions between the terminal post 300 and the tabs 211. Furthermore, since the surfaces of the first welding portion 410 and the second welding portion 420 of the soldering structure 400 are both part of a sphere, they make sufficient contact with the tabs 211 and the second connecting portions 320, resulting in lower resistance at the welding positions. Therefore, the aforementioned battery cell 10 can reduce the resistance at each welding position while reducing the number of welding positions, thus significantly reducing the internal resistance of the aforementioned battery cell 10.

[0096] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A battery cell, characterized by, include: The outer casing includes a first wall, the first wall being provided with a first through hole; A battery cell assembly is housed within the housing, the battery cell assembly including at least two sets of electrode tabs; and The pole includes a first connecting part and at least two second connecting parts. The first connecting part is located on a first side in the thickness direction of the first wall, and the at least two second connecting parts are spaced apart along the width direction of the first wall. Each second connecting part is connected to the first connecting part and extends from the first through hole to a second side in the thickness direction of the first wall. Wherein, at least two second connecting portions are correspondingly provided with at least two sets of electrodes, and each set of electrodes is connected to the electrode welding surface of the corresponding second connecting portion by at least one solder mark structure. Each solder mark structure includes a first welding portion extending into the electrode and a second welding portion extending into the second connecting portion. The first welding portion and the second welding portion together constitute at least a spherical shape.

2. The battery cell of claim 1, wherein, The first wall is a cover plate, the outer casing includes the cover plate and the housing, the battery cell assembly is housed within the housing, and the cover plate is sealed at the opening of the housing; and / or, The battery cell assembly includes at least two battery cells arranged side by side along the width direction of the first wall, each battery cell having a set of tabs extending out, and the tabs of at least two battery cells being arranged in a one-to-one correspondence with at least two second connection portions.

3. The battery cell according to claim 1 or 2, characterized in that, The center of the sphere containing the first welded portion and the second welded portion is located at the interface between the second connecting portion and the electrode tab.

4. The battery cell according to claim 1 or 2, characterized in that, The second welded part is hemispherical.

5. The battery cell according to claim 1 or 2, characterized in that, There is only one weld mark structure between the electrode tab and the electrode tab welding surface of the corresponding second connecting part, and the maximum cross-sectional area of ​​the second welding part in the thickness direction of the second connecting part is less than or equal to 0.32 times the area of ​​the electrode tab welding surface.

6. The battery cell according to claim 1 or 2, characterized in that, A plurality of welding structures are arranged between the tab and the tab welding surface of the corresponding second connecting portion, and the maximum cross-sectional area of each second welding portion in the thickness direction of the second connecting portion is less than or equal to 2π mm 2 .

7. The battery cell according to claim 1 or 2, characterized in that, Each set of electrode tabs and the corresponding second connecting part have multiple solder marks formed between them, and the multiple solder marks are arranged at intervals.

8. The battery cell according to claim 1 or 2, characterized in that, It also includes a tab pad, which is located on the side of the tab away from the tab welding surface and is welded to the tab.

9. The battery cell of claim 2, wherein, In the first wall thickness direction, the projection of the first connecting part does not coincide with the projection of the first through hole, and the projection of the second connecting part covers the projection of the first through hole.

10. The battery cell of claim 9, wherein, Each of the second connecting portions extends from the first side of the first wall to the second side of the first wall to form a connecting sub-portion, and the electrode welding surface is located on the surface of the connecting sub-portion extending beyond the second side of the cover plate.

11. The battery cell of claim 10, wherein, It also includes a first insulating member, which includes a first insulating portion and a second insulating portion. At least a portion of the first insulating portion is disposed between the first connecting portion and the first wall. The second insulating portion covers at least a portion of the surface of the second connecting portion away from the first wall, and the second insulating portion is provided with a clearance hole that exposes a portion of the surface of the second connecting portion.

12. The battery cell of claim 11, wherein, The second connecting part is provided with a groove at the position corresponding to the clearance hole, and the groove is located on the back side of the connecting part.

13. The battery cell of claim 12, wherein, The area of ​​the clearance hole on the plane parallel to the first wall is larger than the area of ​​the groove opening.

14. The battery cell of claim 12, wherein, The minimum distance between the edge of the groove away from the first wall side and the edge of the second insulating part is greater than 0.

15. The battery cell according to claim 12, characterized in that, A sealing element is provided inside the clearance hole, and the sealing element blocks the clearance hole.

16. The battery cell of claim 1 or 2, wherein, The pole also includes at least two transition portions, and the at least two transition portions are respectively arranged in a one-to-one correspondence with at least two second connecting portions. Each second connecting portion is electrically connected to the first connecting portion through the corresponding transition portion.

17. The battery cell of claim 16, wherein, A fusible portion is formed on the transition portion, the flow area of ​​the fusible portion is smaller than the flow area of ​​the first connecting portion, and the flow area of ​​the fusible portion is smaller than the flow area of ​​the second connecting portion.

18. The battery cell of claim 1 or 2, wherein, The pole is integrally stamped.

19. A battery, characterized by It includes a plurality of battery cells as described in any one of claims 1 to 18, wherein the plurality of battery cells are electrically connected by an electrical connector, and the electrical connector is connected to the first connection portion.

20. An electrical device, comprising: Includes a battery cell as described in any one of claims 1 to 18 or a battery as described in claim 19.

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