A battery cell, a battery, and an electrical device.

Abstract

This application relates to a battery cell, a battery, and an electrical device. The battery cell includes: a cover plate; terminals disposed on the cover plate; an insulating plate including an insulating plate body and a pressure plate, the insulating plate body and the cover plate being stacked; the pressure plate being disposed on the side of the insulating plate body away from the cover plate; and an electrode assembly including a cell body and tabs, the cell body having an electrode sheet, the electrode sheet having a winding start end, one end of the tab being connected to the electrode sheet; the tab having a connecting section located between the insulating plate body and the pressure plate, the connecting section being electrically connected to the terminal; wherein, the pressure plate has a hollow portion, and along the winding direction of the cell body, the connecting section has a second side disposed away from the winding start end, the second side of the connecting section being exposed at the hollow portion.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, specifically to a battery cell, a battery, and an electrical device. Background Technology

[0002] Lithium batteries consist of a core. During production, a positive electrode adapter is used to weld and fix the positive tab of the core to the positive terminal, and a negative electrode adapter is used to weld and fix the negative tab of the core to the negative terminal. A lower plastic insert is used to insulate the adapter from the cover plate. To shape and support the positive and negative tabs during core assembly and to prevent defects such as inverted insertion or cracking, a spacer is placed between the tab and the core, and the spacer is connected to the lower plastic insert.

[0003] When the pad and lower plastic are fixed, the pad exerts a compressive force on the positive and negative tabs, causing the tabs to pull on the electrode sheets of the core. This makes the connection between the tabs and the electrode sheets (i.e., the root of the tabs) prone to cracking, especially at the base of the tabs. Figure 1 The right root of the left electrode shown is in a straightened and taut state because it is far away from the winding feed inlet, which makes it more prone to cracking. Utility Model Content

[0004] Therefore, it is necessary to provide a battery cell, battery, and power device that can reduce the risk of cracking at the base of the tab to address the above problems.

[0005] On one hand, this application provides a single battery cell, comprising:

[0006] Cover plate;

[0007] The pole is disposed on the cover plate;

[0008] An insulating board includes an insulating board body and a pressure plate, wherein the insulating board body and the cover plate are stacked; the pressure plate is disposed on the side of the insulating board body opposite to the cover plate; and

[0009] An electrode assembly includes a battery cell body and a tab. The battery cell body has an electrode sheet with a winding start end. One end of the tab is connected to the electrode sheet. The tab has a connecting section located between the insulating plate body and the pressure plate, and the connecting section is electrically connected to the electrode post.

[0010] The pressure plate has a hollowed-out portion. Along the winding direction of the battery cell body, the connecting segment has a second side located away from the winding start end, and the second side of the connecting segment is exposed at the hollowed-out portion.

[0011] In some embodiments, the tab also has a bent section connecting the connecting section and the electrode sheet;

[0012] The pressure plate has a first edge in the first direction that is disposed toward the bent section, and a second edge in the second direction that is disposed near the second side, the second direction being perpendicular to the first direction; wherein, the pressure plate is recessed at the intersection of the extension lines of the first edge and the extension lines of the second edge in a direction away from the bent section to form the hollow portion.

[0013] In some embodiments, the pressure plate further has an inclined edge disposed toward the bent section in the first direction, the inclined edge being inclined relative to the first direction, the inclined edge connecting the first edge and the second edge, and the hollow portion being formed by the inclined edge, an extension line of the first edge and an extension line of the second edge.

[0014] In some embodiments, a rounded chamfer is provided at the intersection of the first edge and the inclined edge, and the radius R of the rounded chamfer is ≥ 0.5 mm.

[0015] In some embodiments, the connecting segment has a free end disposed away from the bending segment, the free end being a distance f from the first edge in the first direction, and the end of the inclined edge away from the first edge being a distance e from the first edge in the first direction, where e < f;

[0016] And / or, the two sides of the connecting segment in the second direction are a first side and a second side, the connection point of the first edge and the inclined edge is located between the first side and the second side, and the distance between the first side and the second side in the second direction is a, and the distance h1 from the connection point of the first edge and the inclined edge to the second side in the second direction satisfies: 2mm≤h1≤(a-2)mm.

[0017] In some embodiments, the tab also has a bent section connecting the connecting section and the electrode sheet;

[0018] The pressure plate has a first edge in a first direction that faces the bent section, and the hollow portion is formed by the first edge being recessed in a direction away from the bent section.

[0019] In some embodiments, the connecting segment has a first side and a second side on its two sides in a second direction perpendicular to the first direction, and the hollow portion has a first side wall and a second side wall on its two sides in the second direction; the first side wall is located between the first side and the second side, and the second side wall is located between the first side wall and the second side wall.

[0020] The distance h2 between the first sidewall and the second side in the second direction satisfies: 2mm≤h2≤(a-2)mm; where a represents the width of the connecting segment in the second direction;

[0021] And / or, the distance between the second side and the second sidewall in the second direction is g, where g ≥ 0.5 mm;

[0022] And / or, the connecting segment has a free end disposed away from the bending segment, the distance between the free end and the side of the pressure plate facing the bending segment in the first direction is f, the depth dimension of the hollow portion in the first direction is e, and e < f.

[0023] In some embodiments, the width dimension of the insulating plate body in the first direction is c, the pressure plate has two oppositely arranged first edges in the first direction, the distance between the two first edges in the first direction is d, and c and d satisfy: 0.5c≤d<c; and / or, the width dimension of the insulating plate body in the first direction is 2mm to 10mm smaller than the width dimension of the cover plate in the first direction.

[0024] On the other hand, this application provides a battery including a battery cell as described in any of the above embodiments.

[0025] On the other hand, this application provides an electrical device including a battery as described in any of the above embodiments.

[0026] Compared with the prior art, this application has the following beneficial effects:

[0027] The aforementioned battery cells, batteries, and electrical devices have perforated sections on the pressure plate, which prevents the second side of the tabs at the perforated sections from being pressed tightly. This greatly reduces the pulling force of the second side of the tabs on the electrode sheets and significantly reduces the risk of cracking at the part of the tab root that is away from the starting end of the winding. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the battery cell structure in one embodiment of this application;

[0029] Figure 2 This is a front view of a single battery cell in one embodiment of this application;

[0030] Figure 3 for Figure 1 The front view of the battery cell shown (the pressure plate is omitted);

[0031] Figure 4 This is a front view of a battery cell in another embodiment of this application. Detailed Implementation

[0032] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application 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 application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0033] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "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 based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not 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 application.

[0034] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0035] In this application, unless otherwise expressly 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 expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0036] In this application, unless otherwise expressly 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.

[0037] 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.

[0038] One embodiment of this application provides an electrical device, a battery, and a battery cell. The electrical device utilizes the following batteries or battery cells as its power source: vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys, power tools, energy storage devices, amusement equipment, elevators, 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 carousels, drop towers, etc.

[0039] 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.

[0040] 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.

[0041] Multiple battery cells can be mounted on supporting structures such as housings, frames, and brackets. Electrical connections between battery cells and between battery cells and the battery management system can be established via electrical connectors, which can be busbars. Alternatively, battery cells can be electrically connected via their respective terminals. For example, between two adjacent battery cells, one battery cell has a slot on its terminal, and the other battery cell has a corresponding insert on its terminal. The insert is inserted into the slot to achieve electrical connection. Therefore, for one battery cell, the aforementioned electrical connector can be the terminal of another battery cell. Similarly, battery cells and the battery management system can also be electrically connected via mutual insertion, which will not be elaborated further. The aforementioned 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 aforementioned battery cell is a lithium-ion square battery.

[0042] The specific structure of the battery cell is described below with reference to the accompanying drawings. Please refer to... Figures 1 to 3 As shown, the battery cell includes a cover plate 10 and a terminal post 20 (see...). Figure 2The battery assembly comprises an insulating plate 30 and an electrode assembly. The electrode post 20 is disposed on the cover plate 10 and serves as the electrode of the battery cell. The insulating plate 30 includes an insulating plate body 31 and a pressure plate 32. The insulating plate body 31 and the cover plate 10 are stacked, and the pressure plate 32 is disposed on the side of the insulating plate body 31 opposite to the cover plate 10. The electrode assembly includes a cell body 41 and an electrode tab 42. The cell body 41 has a wound structure, and the electrode sheet 410 of the cell body 41 has a winding start end A. One end of the electrode tab 42 is connected to the electrode sheet 410, and the other end of the electrode tab 42 is bent to a position between the insulating plate body 31 and the pressure plate 32. The portion of the electrode tab 42 located between the insulating plate body 31 and the pressure plate 32 is a connecting section 423, which is electrically connected to the electrode post 20, thereby realizing the electrical connection between the electrode tab 42 and the electrode post 20 of the electrode assembly. Since the tab 42 is made of multiple layers of sheets, the pressure plate 32 is used to press the tab 42 tightly between the insulating board body 31, thereby shaping and supporting the tab 42 and preventing defects such as inverted insertion caused by the tab 42 being in a loose state. Along the winding direction of the cell body 41, the connecting section 423 of the tab 42 has a first side b1 located near the winding start end A and a second side b2 located away from the winding start end A. Under the pressing action of the pressure plate 32, the tab 42 exerts a certain amount of tension on the electrode sheet 410, allowing the winding start end A of the electrode sheet 410 to contract towards the tab 42, greatly reducing the risk of cracking at the part of the tab 42 facing the winding start end A. However, the electrode sheet 410 on the second side b2 of the tab 42 is in a straightened and taut state, so the part of the tab 42 away from the winding start end A is prone to cracking.

[0043] To address the issue of cracking at the root of the tab 42, in this embodiment, the pressure plate 32 has a perforated portion 320, exposing the second side b2 of the connecting section 423 at the perforated portion 320. Because the pressure plate 32 has the perforated portion 320, the second side b2 of the tab 42 at the perforated portion 320 is not compressed, thus greatly reducing the pulling force of the second side b2 of the tab 42 on the electrode sheet 410, significantly reducing the risk of cracking at the root of the tab 42 away from the winding start end A.

[0044] In a specific embodiment, the battery cell further includes a housing with an opening at at least one end. The electrode assembly is inserted into the housing through this opening. The cover plate 10 is placed over the opening of the housing to enclose the electrode assembly within the housing. An insulating plate body 31 is located on the side of the cover plate 10 facing away from the electrode assembly, serving to form insulation between the cover plate 10 and the electrode assembly. One end of the tab 42 is connected to the electrode plate 410 of the cell body, and the other end is bent between the insulating plate body 31 and the pressure plate 32. The portion of the tab 42 located between the insulating plate body 31 and the pressure plate 32 is a connecting section 423, which is electrically connected to the terminal post 20 on the cover plate 10.

[0045] Optionally, the dimension of the insulating plate body 31 in the first direction X1 is c, and the dimension of the pressure plate 32 in the first direction X1 is d. Wherein, c and d satisfy: 0.5c ≤ d < c. The first direction X1 is the width direction of the cover plate 10.

[0046] It should be noted that the larger the size of the pressure plate 32 in the first direction X1, the larger the area of ​​the connecting section 423 of the electrode tab 42 that is pressed and shaped; the smaller the size of the pressure plate 32 in the first direction X1, the smaller the area of ​​the connecting section 423 of the electrode tab 42 that is pressed and shaped. If the size of the pressure plate 32 in the first direction X1 is too large, it is easy to cause the electrode tab 42 to pull the electrode sheet 410 with a greater force, thereby increasing the risk of cracking at the root of the electrode tab 42. If the size of the pressure plate 32 in the first direction X1 is too small, the risk of the electrode tab 42 being inserted backward increases. In this embodiment, c and d are set to 0.5c≤d<c, so that the size of the pressure plate 32 in the first direction X1 is moderate, avoiding the pressure plate 32 being too large or too small in the first direction X1.

[0047] It should be noted that if the width of the insulating plate body 31 is too large, it greatly increases the difficulty of assembling the electrode assembly into the housing; if the width of the insulating plate body 31 is too small, it greatly reduces the insulation effect and increases the risk of short circuit. Specifically, in this embodiment, the dimension of the insulating plate body 31 in the first direction X1 is 2mm to 10mm smaller than the dimension of the cover plate 10 in the first direction X1, thus ensuring both insulation effect and lower difficulty in assembling the electrode assembly into the housing. Specifically, the dimension of the insulating plate body 31 in the first direction X1 is 2mm, 4mm, 6mm, 7mm, 9mm, or 10mm smaller than the dimension of the cover plate 10 in the first direction X1. Further, the dimension of the insulating plate body 31 in the first direction X1 is reduced by 1mm to 5mm on one side compared to the dimension of the cover plate 10 in the first direction X1. Specifically, the dimension of the insulating plate body 31 in the first direction X1 is reduced by 1mm, 2mm, 3mm, 3.5mm, 4.5mm, or 5mm on one side compared to the dimension of the cover plate 10 in the first direction X1.

[0048] Similarly, the dimension of the insulating plate body 31 in the second direction X2, perpendicular to the first direction X1, is 2mm to 10mm smaller than the dimension of the cover plate 10 in the second direction X2. This ensures both insulation performance and reduces the difficulty of assembling the electrode assembly into the housing. Specifically, the dimension of the insulating plate body 31 in the second direction X2, perpendicular to the first direction X1, is 2mm, 3mm, 5mm, 6mm, 8mm, or 10mm smaller than the dimension of the cover plate 10 in the second direction X2. Further, the dimension of the insulating plate body 31 in the second direction X2 is reduced by 1mm to 5mm on one side compared to the dimension of the cover plate 10 in the second direction X2. The first direction X1 is the width direction of the cover plate 10, and the second direction X2 is the length direction of the cover plate 10. Specifically, the dimension of the insulating plate body 31 in the second direction X2 is reduced by 1mm, 1.5mm, 2.5mm, 3mm, 4mm, or 5mm on one side compared to the dimension of the cover plate 10 in the second direction X2.

[0049] Furthermore, the battery cell also includes an adapter piece 50, which is disposed between the pressure plate 32 and the insulating plate body 31. The connecting section 423 of the tab 42 is located between the adapter piece 50 and the pressure plate 32. On the one hand, the pressure plate 32 can guide the tab 42 to bend, preventing the tab 42 from being inserted backwards into the electrode assembly. On the other hand, the pressure plate 32 can isolate the electrode assembly and the tab 42, ensuring that the weld slag formed by welding the connecting end 423 of the tab 42 and the adapter piece 50 will not fall off. The insulating plate body 31 has a through hole B corresponding to the pole 20. The pole 20 passes through the through hole B and is welded to the adapter piece 50 on the side of the pole 20 facing the electrode assembly, thereby electrically connecting the connecting section 423 of the tab 42, the adapter piece 50, and the pole 20. Optionally, the adapter piece 50 and the pole 20 can be electrically connected by laser welding, and the adapter piece 50 and the tab 42 can be electrically connected by ultrasonic welding.

[0050] It should be noted that the pressure plate 32 is integrally formed with the insulating plate body 31 at one end in the second direction X2, and a crease is formed at the connection between the pressure plate 32 and the insulating plate body 31 so that the pressure plate 32 can be folded around the crease. The other end of the pressure plate 32 is detachably connected to the insulating plate body 31, for example, by a snap-fit ​​connection, so that the connecting section 423 of the electrode tab 42 and the adapter piece 50 can be fixed between the pressure plate 32 and the insulating plate body 31. Of course, the pressure plate 32 and the insulating plate body 31 can also be set independently, and the pressure plate 32 and the insulating plate body 31 can be detachably connected, for example, by a snap-fit ​​connection, so that the connecting section 423 of the electrode tab 42 and the adapter piece 50 can be fixed between the pressure plate 32 and the insulating plate body 31. The snap-fit ​​structure used for the connection between the pressure plate 32 and the insulating plate body 31 can adopt relatively mature existing technology, and is not limited here.

[0051] See Figure 1As shown, the electrode assembly includes a battery cell body and two tabs 42 with opposite polarities; the two tabs 42 with opposite polarities are a positive tab 42a and a negative tab 42b; the battery cell body includes two electrode plates 410 with opposite polarities and a separator membrane disposed between the two electrode plates 410; the two electrode plates 410 are a positive electrode plate and a negative electrode plate; the positive tab 42a is connected to the positive electrode plate, and the negative tab 42b is connected to the negative electrode plate. Correspondingly, two pole posts 20 are provided, namely a positive pole post 20a and a negative pole post 20b; two adapter plates 50 are provided, namely a positive adapter plate 50a and a negative adapter plate 50b. The positive tabs 42a and the negative tabs 42b are arranged at intervals along the second direction X2. Positive terminal 20a and negative terminal 20b are arranged at intervals along the second direction X2 on the cover plate 10, and positive adapter piece 50a and negative adapter piece 50b are arranged at intervals along the second direction X2 on the insulating plate body 31. The insulating plate body 31 has two through holes B corresponding to the positive terminal 20a and negative terminal 20b, respectively.

[0052] A positive terminal post 20a is disposed in one of the through holes B and connected to the positive adapter piece 50a, and a negative terminal post 20b is disposed in the other through hole B and connected to the negative adapter piece 50b. When one pressure plate 32 is disposed, one pressure plate 32 covers both the positive terminal lug 42a and the negative terminal lug 42b, and the pressure plate 32 is engaged with the insulating plate body 31. At this time, the pressure plate 32 has a cutout portion 320 at the second side b2 position opposite to the positive terminal lug 42a, and the pressure plate 32 also has a cutout portion 320 at the second side b2 position opposite to the negative terminal lug 42b.

[0053] Of course, when two pressure plates 32 are provided, the two pressure plates 32 are a positive pressure plate 32a and a negative pressure plate 32b, respectively. The positive pressure plate 32a and the insulating plate body 31 are rotatably connected. The positive pressure plate 32a covers the connecting section 423 of the two positive tabs 42a and the positive adapter piece 50a, and the positive pressure plate 32a and the insulating plate body 31 are snap-fit ​​connected. The negative pressure plate 32b and the insulating plate body 31 are rotatably connected. The negative pressure plate 32b covers the connecting section 423 of the two negative tabs 42b and the negative adapter piece 50b, and the negative pressure plate 32b and the insulating plate body 31 are snap-fit ​​connected. In order to reduce the risk of cracking at the root of the positive electrode tab 42a and the part of the negative electrode tab 42b that is away from the starting end A of the winding, a hollow part 320 is provided at the second side b2 position of the positive pressure plate 32a facing the positive electrode tab 42a, and a hollow part 320 is provided at the second side b2 position of the negative pressure plate 32b facing the negative electrode tab 42b.

[0054] See Figure 2As shown, when two electrode assemblies are provided and arranged opposite each other along the first direction X1, the positive electrode tabs 42a of the two electrode assemblies are arranged opposite each other along the first direction X1, and the negative electrode tabs 42b of the two electrode assemblies are also arranged opposite each other along the first direction X1. In this case, when only one pressure plate 32 is provided, the aforementioned hollow portion 320 is provided on both sides of the pressure plate 32 along the first direction X1 at the position of the second side b2 directly opposite the two positive electrode tabs 42a; and the aforementioned hollow portion 320 is also provided on both sides of the pressure plate 32 along the first direction X1 at the position of the second side b2 directly opposite the two negative electrode tabs 42b. Of course, when two pressure plates 32 are provided, namely a positive pressure plate 32a and a negative pressure plate 32b, the positive pressure plate 32a has the aforementioned hollow portion 320 on both sides in the first direction X1, and the second side b2 of the connecting section 423 of the two positive electrode tabs 42a is exposed at the two hollow portions 320 respectively; the negative pressure plate 32b has the aforementioned hollow portion 320 on both sides in the first direction X1, and the second side b2 of the connecting section 423 of the two negative electrode tabs 42b is exposed at the two hollow portions 320 respectively.

[0055] The structure of the cutout portion 320 can vary, as long as it ensures that the second side b2 of the electrode tab is exposed at the cutout portion 320. In some embodiments, please refer to [link to relevant documentation]. Figures 2 to 3 The tab 42 also has a bent section 424 connecting the connecting section 423 and the electrode sheet 410. The pressure plate 32 has a first edge 322 in a first direction X1, facing the bent section 424, and a second edge 325 in a second direction X2, near the second side b2, perpendicular to the first direction X1. At the intersection of the extension lines of the first edge 322 and the second edge 325, the pressure plate 32 is recessed in a direction away from the bent section 424, forming a hollow portion 320. Thus, material is missing at the intersection of the extension lines of the first edge 322 and the second edge 325, forming the hollow portion 320, preventing the tab 42 from being pressed tightly at that location, thereby reducing the risk of cracking at the base of the tab 42 away from the winding start end A.

[0056] Furthermore, the pressure plate 32 also has an inclined edge 324 disposed in the first direction X1 toward the bent section 424. The inclined edge 324 is disposed at an inclination relative to the first direction X1 and connects the first edge 322 and the second edge 325. The aforementioned hollow portion 320 is formed by the inclined edge 324, the extension line of the first edge 322, and the extension line of the second edge 325.

[0057] Furthermore, a rounded chamfer is provided at the intersection of the first edge 322 and the inclined edge 324 to prevent the intersection from being too sharp and easily piercing the electrode tab 42. Preferably, the radius R of the rounded chamfer is ≥ 0.5 mm. Specifically, the radius R of the rounded chamfer is 0.5 mm, 0.6 mm, 0.8 mm, 1 mm, 1.3 mm, or 1.5 mm.

[0058] Furthermore, the connecting section 423 of the tab 42 has a free end a2 disposed away from the bending section 424. The distance between this free end a2 and the first edge 322 in the first direction X1 is f. The distance between the end of the inclined edge 324 away from the first edge 322 and the first edge 322 in the first direction X1 is e. These f and e satisfy: e < f. In this way, it is ensured that the free end a2 of the tab 42 is completely pressed and shaped between the pressure plate 32 and the insulating plate body 31, preventing the free end a2 of the tab 42 from inserting into the cell body and forming a short circuit.

[0059] Furthermore, the connection point between the first edge 322 and the inclined edge 324 is located between the first side b1 and the second side b2 of the connecting segment 423, and the distance between the first side b1 and the second side b2 in the second direction X2 is a. The distance from the connection point between the first edge 322 and the inclined edge 324 to the second side b2 in the second direction X2 is h1, where h1 and a satisfy: 2mm≤h1≤(a-2)mm. For example, when a is 15mm, 2mm≤h1≤13mm; when a is 20mm, 2mm≤h1≤18mm.

[0060] It should be noted that the closer the connection point between the first edge 322 and the inclined edge 324 is to the second side b2 of the tab 42, the smaller the area of ​​the hollow portion 320; conversely, the farther away it is from the second side b2 of the tab 42, the larger the area of ​​the hollow portion 320. If the area of ​​the hollow portion 320 is too large, the area of ​​the tab 42 that is compressed and shaped will be smaller, and the area of ​​the tab 42 that is not compressed and shaped will be prone to problems such as folding and inversion. If the area of ​​the hollow portion 320 is too small, the area of ​​the tab 42 that is compressed and shaped will be too large, and the effect on reducing the risk of cracking at the root of the tab 42 away from the starting end A of winding will be insignificant. Setting h1 and a to 2mm≤h1≤(a-2)mm ensures that the area of ​​the hollow portion 320 is neither too large nor too small.

[0061] It should be noted that the cutout portion 320 is not limited to being formed by the extension lines of the inclined edge 324, the first edge 322, and the second edge 325. Please refer to [link / reference]. Figure 4In other embodiments, the cutout 320 is a notch formed by the indentation of the first edge 322 of the pressure plate 32 toward the bent section 424 away from the tab 42. Thus, by providing a notch as the cutout 320 on the first edge 322 of the pressure plate 32, the second side b2 of the connecting section 423 is exposed at this notch, thereby greatly reducing the pulling force of the second side b2 of the tab 42 on the electrode sheet 410, and significantly reducing the risk of cracking at the base of the tab 42 away from the winding start end A. It should be noted that the cutout 320 can be a U-shaped notch or a V-shaped notch, etc., and is not limited here.

[0062] Furthermore, the two side walls of the hollow portion 320 in the second direction X2 are a first side wall c1 and a second side wall c2, respectively. The first side wall c1 is located between the first side edge b1 and the second side edge b2 of the connecting segment 423, and the second side edge b2 of the connecting segment 423 is located between the first side wall c1 and the second side wall c2 of the hollow portion 320. In this way, the second side edge b2 of the connecting segment 423 is exposed in the hollow area between the first side wall c1 and the second side wall c2, thereby greatly reducing the pulling force of the second side edge b2 of the connecting segment 423 on the electrode sheet 410, and greatly reducing the risk of cracking at the part of the electrode tab 42 that is away from the winding start end A.

[0063] Optionally, the distance h2 between the first sidewall c1 of the hollow portion 320 and the second sidewall b2 of the connecting segment 423 in the second direction X2 satisfies: 2mm≤h2≤(a-2)mm; where a represents the width dimension of the connecting segment 423 in the second direction X2, that is, the distance between the first sidewall b1 and the second sidewall b2 in the second direction X2 is a.

[0064] It should be noted that a smaller h2 results in a smaller area of ​​the exposed connecting section 423 at the hollowed-out portion 320, while a larger h2 results in a larger area of ​​the exposed connecting section 423 at the hollowed-out portion 320. If h2 is too large, the area where the tab 42 is compressed and shaped will be smaller, and the area where the tab 42 is not compressed and shaped will be prone to problems such as folding and inversion. If h2 is too small, the area where the tab 42 is compressed and shaped will be too large, and the effect on reducing the risk of cracking at the part of the tab 42 root away from the winding start end A will not be significant. In this embodiment, h2 is set to 2mm≤h1≤(a-2)mm to ensure that h2 is neither too large nor too small.

[0065] Optionally, the distance between the second side b2 of the connecting section 423 and the second sidewall c2 of the hollow portion 320 in the second direction X2 is g, where g ≥ 0.5 mm, thereby avoiding scratching the electrode tab 42 when the pressure plate 32 is fastened to the insulating board body 31 due to g being too small. Specifically, g can be 0.5 mm, 1 mm, 1.5 mm, or 2 mm.

[0066] Optionally, the distance between the free end a2 of the tab 42 and the side of the pressure plate 32 facing the bent section 424 (i.e., the first edge 322) in the first direction X1 is f, and the depth dimension of the hollow portion 320 in the first direction X1 is e, where e < f. This ensures that the free end a2 of the tab 42 is completely pressed and shaped between the pressure plate 32 and the insulating plate body 31, preventing the free end a2 of the tab 42 from inserting into the cell body and forming a short circuit.

[0067] 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.

[0068] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery cell, characterized in that, include: Cover plate (10); A pole post (20) is disposed on the cover plate (10); An insulating board (30) includes an insulating board body (31) and a pressure plate (32), wherein the insulating board body (31) and the cover plate (10) are stacked; the pressure plate (32) is disposed on the side of the insulating board body (31) away from the cover plate (10); and The electrode assembly includes a cell body (41) and a tab (42). The cell body (41) has an electrode plate (410) with a winding start end (A). One end of the tab (42) is connected to the electrode plate (410). The tab (42) has a connecting section (423) located between the insulating plate body (31) and the pressure plate (32). The connecting section (423) is electrically connected to the pole post (20). The pressure plate (32) is provided with a hollow part (320). Along the winding direction of the battery cell body (41), the connecting section (423) has a second side (b2) located away from the winding start end (A). The second side (b2) of the connecting section (423) is exposed at the hollow part (320).

2. The battery cell according to claim 1, characterized in that, The tab (42) also has a bent section (424) connecting the connecting section (423) and the electrode (410); The pressure plate (32) has a first edge (322) in a first direction (X1) facing the bent section (424), and the pressure plate (32) has a second edge (325) in a second direction (X2) near the second side (b2), the second direction (X2) being perpendicular to the first direction (X1); wherein, the pressure plate (32) is recessed at the intersection of the extension line of the first edge (322) and the extension line of the second edge (325) in a direction away from the bent section (424) to form the hollow portion (320).

3. The battery cell according to claim 2, characterized in that, The pressure plate (32) also has an inclined edge (324) disposed toward the bent section (424) in the first direction (X1), the inclined edge (324) being inclined relative to the first direction (X1), the inclined edge (324) being connected between the first edge (322) and the second edge (325), and the hollow portion (320) being formed by being surrounded by the inclined edge (324), the extension line of the first edge (322) and the extension line of the second edge (325).

4. The battery cell according to claim 3, characterized in that, A rounded chamfer is provided at the intersection of the first edge (322) and the inclined edge (324), and the radius R of the rounded chamfer is ≥ 0.5 mm.

5. The battery cell according to claim 3, characterized in that, The connecting segment (423) has a free end (a2) disposed away from the bending segment (424), the free end (a2) being a distance f from the first edge (322) in the first direction (X1), and the end of the inclined edge (324) away from the first edge (322) being a distance e from the first edge (322) in the first direction (X1), where e < f; And / or, the two sides of the connecting segment (423) in the second direction (X2) are a first side (b1) and a second side (b2) respectively, the connection point of the first edge (322) and the inclined edge (324) is located between the first side (b1) and the second side (b2), and the distance between the first side (b1) and the second side (b2) in the second direction (X2) is a, and the distance h1 from the connection point of the first edge (322) and the inclined edge (324) to the second side (b2) in the second direction (X2) satisfies: 2mm≤h1≤(a-2)mm.

6. The battery cell according to claim 1, characterized in that, The tab (42) also has a bent section (424) connecting the connecting section (423) and the electrode (410); The pressure plate (32) has a first edge (322) in a first direction (X1) facing the bent section (424), and the hollow portion (320) is formed by the first edge (322) being recessed in a direction away from the bent section (424).

7. The battery cell according to claim 6, characterized in that, The connecting segment (423) has a first side (b1) and a second side (b2) on its two sides in a second direction (X2) perpendicular to the first direction (X1), and the hollow part (320) has a first side wall (c1) and a second side wall (c2) on its two sides in the second direction (X2); the first side wall (c1) is located between the first side (b1) and the second side (b2), and the second side (b2) is located between the first side wall (c1) and the second side wall (c2); The distance h2 between the first sidewall (c1) and the second sidewall (b2) in the second direction (X2) satisfies: 2mm≤h2≤(a-2)mm; where a represents the width dimension of the connecting segment (423) in the second direction (X2); And / or, the distance between the second side edge (b2) and the second sidewall (c2) in the second direction (X2) is g, where g ≥ 0.5 mm; And / or, the connecting segment (423) has a free end (a2) disposed away from the bending segment (424), the free end (a2) being a distance f from the side of the pressure plate (32) facing the bending segment (424) in the first direction (X1), and the depth dimension of the hollow portion (320) in the first direction (X1) being e, where e < f.

8. The battery cell according to claim 2 or 6, characterized in that, The width dimension of the insulating plate body (31) in the first direction (X1) is c, the pressure plate (32) has two oppositely arranged first edges (322) in the first direction (X1), the distance between the two first edges (322) in the first direction (X1) is d, and c and d satisfy: 0.5c≤d<c; and / or, the width dimension of the insulating plate body (31) in the first direction (X1) is 2mm to 10mm smaller than the width dimension of the cover plate (10) in the first direction (X1).

9. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 8.

10. An electrical device, characterized in that, Includes the battery as described in claim 9.

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