Battery cells and batteries

Abstract

The application provides a battery monomer and a battery, the battery monomer comprising: a shell, an electrode assembly and a cover plate assembly; the cover plate assembly comprising a cover plate body and a lower insulating piece, the cover plate body being provided with an electrode terminal and an explosion-proof valve which are spaced apart along a first direction; the lower insulating piece comprising an insulating body, a bottom surface of the insulating body being formed with a first protrusion which is protruding, the first protrusion being formed with a gas flow sub-channel which penetrates along the first direction, the insulating body being formed with a ventilation opening which corresponds to the explosion-proof valve, the insulating body and the electrode body defining a gas flow space, the gas flow sub-channel, the gas flow space and the ventilation opening being sequentially communicated to form a gas flow channel; an adapter being arranged in the gas flow space, a bottom surface of the adapter being provided with a protruding structure which protrudes towards the electrode assembly. The battery monomer and the battery provided by the application can ensure that the gas can smoothly pass through the gas flow channel and be discharged from the battery monomer in time and quickly.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a battery cell and a battery. Background Technology

[0002] In the development of battery technology, besides improving the performance of individual battery cells, safety is also a crucial issue that cannot be ignored. If the safety of individual battery cells cannot be guaranteed, then those cells cannot be used. Therefore, how to enhance the safety of individual battery cells is a pressing technical problem that needs to be solved in battery technology. Utility Model Content

[0003] In view of this, the purpose of this application is to propose a battery cell and a battery to at least partially solve the problem of how to enhance the safety of the battery cell.

[0004] Based on the above objectives, a first aspect of this application provides a battery cell, comprising: a housing having at least one open end; an electrode assembly including an electrode body and tabs extending from the electrode body; a cover assembly covering the open end and forming a receiving space with the housing for accommodating the electrode assembly; the cover assembly including a cover body and a lower insulating member; the cover body being provided with electrode terminals and an explosion-proof valve spaced apart along a first direction, the first direction intersecting the thickness direction of the battery cell; the lower insulating member being connected to the side of the cover body near the electrode assembly, the lower insulating member including an insulating body, the surface of the insulating body away from the cover body being formed with a surface facing towards the electrode assembly. The electrode assembly has a first protrusion located on the side of the electrode terminal away from the explosion-proof valve along the first direction. The first protrusion forms an airflow sub-channel extending along the first direction. The insulating body forms a vent opening corresponding to the explosion-proof valve. The portion of the insulating body located between the first protrusion and the vent opening defines an airflow space with the electrode body. The airflow sub-channel, the airflow space, and the vent opening are sequentially connected to form an airflow channel. An adapter is disposed within the airflow space, and the electrode tab is electrically connected to the electrode terminal through the adapter. The surface of the adapter near the electrode assembly has a protruding structure protruding towards the electrode assembly.

[0005] Optionally, the adapter is welded to the electrode terminal and a solder mark is formed between them, and the protrusion structure at least partially covers the solder mark; along the first direction, the tab is spaced apart from the first protrusion, and the minimum spacing distance between the tab and the adjacent first protrusion is L1, and the dimension of the lower insulating member along the first direction is L, 2mm < L1 ≤ L / 5.

[0006] Optionally, the first protrusion has an inner wall close to the tab, and the orthographic projection of the tab along the first direction onto the inner wall of the first protrusion is the tab projection, which does not completely block the opening of the airflow sub-channel located on the inner wall of the first protrusion.

[0007] Optionally, the maximum dimension of the airflow sub-channel along the thickness direction of the battery cell is W1, and the maximum dimension of the overlapping portion of the tab projection and the opening of the airflow sub-channel along the thickness direction of the battery cell is W2, where W2≤W1×2 / 3.

[0008] Optionally, a rounded chamfer with radius r is formed between the side edge of the electrode near the first protrusion and the free end of the electrode, where 5mm≤r≤10mm.

[0009] Optionally, the same adapter is connected to two tabs, the two tabs are spaced apart along the thickness direction of the battery cell, and the minimum spacing distance is W3. The dimension of the lower insulating member along the thickness direction of the battery cell is W, where W / 3≤W3≤W×2 / 3.

[0010] Optionally, the protruding structure is a gel along the height direction of the battery cell. The orthographic projection of the protruding structure on the adapter is a support projection. The solder mark is located within the support projection. The minimum interval between the edge of the support projection and the edge of the adjacent solder mark is D, where D ≥ 1 mm.

[0011] Optionally, along the height direction of the battery cell, the protrusion structure does not extend beyond the surface of the first protrusion away from the insulating body.

[0012] Optionally, the thickness of the protrusion structure is H1, and the thickness of the tab is H2, where 100μm < H1 < 2 × H2.

[0013] Based on the same inventive concept, the second aspect of this application also provides a battery, including a battery cell as described in the first aspect.

[0014] As can be seen from the above, the battery cell and battery provided in this application have a protruding structure on the surface of the adapter near the electrode assembly, protruding towards the electrode assembly. When the electrode body expands or moves towards the cover assembly, the electrode body will preferentially contact the protruding structure rather than directly contact the adapter. The protruding structure can prevent the electrode body from continuing to move or expand upwards, ensuring that a gap for gas flow remains between the opposing surfaces of the electrode body and the adapter. After flowing out from the gas flow sub-channel, the gas can smoothly pass through the gas flow space through the aforementioned gap and flow to the explosion-proof valve through the vent opening. The space between the adapter and the insulating body is limited. When the electrode body contacts the adapter, the exhaust efficiency is low. The protruding structure, by preventing the electrode body from moving or expanding further upwards, can increase the space between the electrode body and the insulating body, thereby improving the exhaust efficiency.

[0015] When the electrode body of the battery cell expands or moves, the gas in the containment space can still flow smoothly and timely in the airflow channel, and can eventually pass through the explosion-proof valve to be discharged from the battery cell, which helps to improve the exhaust efficiency and safety performance of the battery cell. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this application or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a partial cross-sectional schematic diagram of a battery cell with the first structure according to an embodiment of this application;

[0018] Figure 2 This is a partial cross-sectional schematic diagram of a battery cell with the second structure according to an embodiment of this application;

[0019] Figure 3 This is a schematic diagram of a battery cell with the first structure according to an embodiment of this application experiencing thermal runaway;

[0020] Figure 4 This is a partial cross-sectional schematic diagram of a battery cell with a third structure according to an embodiment of this application;

[0021] Figure 5 This is a partial cross-sectional schematic diagram of a battery cell with the fourth structure according to an embodiment of this application;

[0022] Figure 6 This is a partial cross-sectional schematic diagram of a battery cell with the third structure according to an embodiment of this application during thermal runaway;

[0023] Figure 7This is a bottom view schematic diagram of the cover plate assembly and related structural components of a battery cell with a third structure according to an embodiment of this application;

[0024] Figure 8 for Figure 4 A schematic diagram of the cross-section AA in the middle.

[0025] Explanation of reference numerals in the attached figures:

[0026] 100. Shell; 110. Open end;

[0027] 200. Cover plate assembly; 210. Cover plate body; 220. Lower insulating component; 221. Insulating body; 222. First protrusion; 223. Second protrusion; 230. Electrode terminal; 240. Explosion-proof valve;

[0028] 300. Accommodation space;

[0029] 400. Electrode assembly; 410. Electrode body; 420. Tab; 421. Rounded chamfer;

[0030] 500, airflow channel; 510, airflow space; 520, airflow sub-channel; 530, exhaust channel; 531, ventilation opening;

[0031] 600. Adapter; 610. Solder mark;

[0032] 700. Raised structure. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0034] It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components described in these embodiments do not limit the scope of this application.

[0035] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0036] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0037] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0038] Figure 1 A partial cross-sectional schematic diagram of the battery cell of the first structure is shown.

[0039] by Figure 1 Taking the structure and orientation shown as an example, the battery cell may include a housing 100 and a cover assembly 200. The housing 100 has an opening 110 only at the top, that is, the housing 100 has one opening 110. The cover assembly 200 includes a cover body 210, and electrode terminals 230 (including positive and negative terminals) and an explosion-proof valve 240 connected to the cover body 210. The cover body 210 covers the opening 110.

[0040] The cover body 210 and the housing 100 can be made of aluminum, steel, or other materials. The cover body 210 and the housing 100 can be connected by means of adhesive, riveting, welding, or other methods. For example, the cover body 210 and the housing 100 are made of aluminum, and the cover body 210 and the housing 100 are welded together.

[0041] Figure 2 A partial cross-sectional schematic diagram of the battery cell with the second structure is shown.

[0042] by Figure 2 Taking the structure and orientation shown as an example, the housing 100 may also have two open ends 110, which can be arranged opposite to each other on the housing 100. Correspondingly, two cover plate assemblies 200 are also provided, and each cover plate assembly 200 is connected to one of the open ends 110. Each cover plate assembly 200 includes a cover plate body 210, and each cover plate body 210 is connected to an electrode terminal 230. The cover plate body 210 and the electrode terminal 230 can be connected by welding, gluing, riveting, etc. It should be noted that the number of electrode terminals 230 connected to each cover plate body 210 is not limited, for example... Figure 2One of the cover plate bodies 210 is connected to a positive terminal, and the other cover plate body 210 is connected to a negative terminal and an explosion-proof valve 240. Understandably, more than one electrode terminal 230 can also be provided on one cover plate body 210, such as two or more. The polarities of these electrode terminals 230 can be the same or not completely the same.

[0043] Regardless of whether the battery cell has the first or second structure described above, the cover assembly 200 and the housing 100 can be closed to form a receiving space 300 for accommodating the electrode assembly 400. The housing 100 can be integrally formed or not integrally formed; this is not limited here. The housing 100 can be formed by stretching, casting, bending, splicing, etc.; this is also not limited here.

[0044] The electrode assembly 400 may include an electrode body 410, which includes a wound or stacked body formed by an electrode sheet and a separator. The electrode sheet includes a positive electrode sheet and a negative electrode sheet, which are alternately arranged. The separator is used to isolate adjacent positive and negative electrode sheets. The electrode sheet includes a metal substrate and an active material layer disposed on a portion of the surface of the substrate. The portion of the electrode sheet without the active material layer is led out from the electrode body 410 to form a tab 420. The tab 420 includes a positive tab led out from the positive electrode sheet and a negative tab led out from the negative electrode sheet. The positive tab is electrically connected to the positive terminal, and the negative tab is electrically connected to the negative terminal.

[0045] It should be noted that an electrode body 410 includes a multi-layer structure formed by a positive electrode plate, a negative electrode plate, and a separator. Correspondingly, multiple positive tabs and multiple negative tabs will be drawn out from the electrode body 410. Multiple positive tabs in the same electrode body 410 can be stacked to form a cluster of positive tabs, and multiple negative tabs can be stacked to form a cluster of negative tabs.

[0046] When the number of electrode components 400 in the same battery cell is greater than two, these electrode bodies 410 can be divided into multiple groups. For example, when a battery cell includes four electrode components 400, the four electrode components 400 can be grouped in pairs; when a battery cell includes six electrode components 400, they can be grouped in pairs or in groups of three. All the multiple layers of positive tabs included in all the electrode bodies 410 in each group are stacked together to form a cluster of positive tabs, and all the multiple layers of negative tabs included in all the electrode bodies 410 in each group are stacked together to form a cluster of negative tabs.

[0047] In other words, a cluster of positive electrodes may include multiple layers of positive electrodes from the same electrode body 410, or it may include multiple layers of positive electrodes from at least two electrode bodies 410. The same applies to negative electrodes, which will not be elaborated here.

[0048] When assembling a battery cell, a cluster of tabs 420 (i.e., a cluster of positive tabs or a cluster of negative tabs) needs to be electrically connected to the corresponding electrode terminal 230. After connection, the cluster of tabs 420 forms a whole, which can be referred to as a single tab 420. That is, in the embodiments of this application, a single tab 420 does not only refer to a single layer of tabs, but can also be a relatively compact cluster of tabs 420 formed by multiple layers of tabs.

[0049] During the production, transportation, or use of a battery cell, the electrode assembly 400 may experience thermal runaway. When thermal runaway occurs, high-temperature gas is generated. As this high-temperature gas accumulates within the containment space 300, the pressure within the space increases. When the pressure within the containment space 300 reaches a certain level, it forces the explosion-proof valve 240 to open, allowing the high-temperature gas to escape through the open valve, thus preventing the battery cell from exploding.

[0050] Within the containment space 300, the gap between the electrode body 410 and the inner wall of the housing 100 (hereinafter referred to as the side gap), and the gap between the electrode body 410 and the cover plate assembly 200 (hereinafter referred to as the top gap) are connected to form a channel for gas flow, so that gas within the containment space 300 can flow through this channel to the opened explosion-proof valve 240, such as... Figure 1 and Figure 2 The direction of gas flow can be seen in [reference]. Figure 1 and Figure 2 The direction of the arrow line in the image.

[0051] Figure 3 A schematic diagram is shown when the battery cell of the first structure experiences thermal runaway.

[0052] The applicant's research found that, such as Figure 3 When a battery cell experiences thermal runaway, the electrode body 410 expands, reducing the side and / or top gaps, and potentially even blocking these channels. Combined with... Figure 3 It can be seen that the explosion-proof valve 240 is connected to the side gap through the top gap. Air in the side gap enters the explosion-proof valve 240 after passing through the top gap. When the top gap narrows, the gas flow in the accommodating space 300 is obstructed, causing the gas in the accommodating space 300 to be unable to be discharged through the explosion-proof valve 240 in a timely manner, which may lead to a safety risk to the battery cell.

[0053] To address the aforementioned issues, this embodiment provides a single battery cell.

[0054] Figure 4 A partial cross-sectional diagram of a battery cell with the third structure is shown. Figure 7 A bottom view schematic diagram showing the cover assembly 200 and related structural components of the battery cell with the third structure is shown.

[0055] like Figure 4 and Figure 7 In some embodiments, the battery cell includes: a housing 100 having at least one open end 110; an electrode assembly 400 including an electrode body 410 and tabs 420 extending from the electrode body 410; a cover assembly 200 covering the open end 110 and forming a receiving space 300 with the housing 100 for accommodating the electrode assembly 400; the cover assembly 200 includes a cover body 210 and a lower insulator 220; the cover body 210 is provided with a first direction (e.g., Figure 4 The electrode terminals 230 and the explosion-proof valve 240 are spaced apart in the X direction of the battery cell, and the first direction is parallel to the thickness direction of the battery cell (e.g., in the X direction). Figure 7 The lower insulating member 220 is connected to the side of the cover plate body 210 near the electrode assembly 400. The lower insulating member 220 includes an insulating body 221. The surface of the insulating body 221 away from the cover plate body 210 (hereinafter referred to as the bottom surface of the insulating body 221) forms a first protrusion 222 protruding towards the electrode assembly 400. The first protrusion 222 is located along the first direction on the side of the electrode terminal 230 away from the explosion-proof valve 240. The first protrusion 222 forms an airflow sub-channel 520 that runs through the first direction. The insulating body 221 forms a corresponding airflow sub-channel 520 to the explosion-proof valve 240. Vent opening 531, the portion of insulating body 221 located between first protrusion 222 and vent opening 531 and electrode body 410 define airflow space 510, airflow sub-channel 520, airflow space 510 and vent opening 531 are sequentially connected to form airflow channel 500; adapter 600 is disposed in airflow space 510, electrode tab 420 is electrically connected to electrode terminal 230 through adapter 600; the surface of adapter 600 near electrode assembly 400 (hereinafter referred to as bottom surface of adapter 600) is provided with protrusion structure 700 protruding towards electrode assembly 400.

[0056] It should be noted that along the height direction of the battery cell (e.g. Figure 1 The first direction is defined as the extension of the line connecting the center point of the orthographic projection of the electrode terminal 230 onto the surface of the cover body 210 and the center point of the orthographic projection of the explosion-proof valve 240 onto the surface of the cover body 210. This first direction can be perpendicular to the thickness direction of the battery cell, or it can form a small angle with the thickness direction of the battery cell; no limitation is made here. In the accompanying drawings of this application, the example shown is that the first direction is perpendicular to the thickness direction of the battery cell.

[0057] For example, the lower insulating member 220 can be connected to the cover plate body 210 by means of bonding, snap-fitting, or thermoforming. The cover plate body 210 can be made of metal, and the lower insulating member 220 is used to improve the insulation performance between the cover plate body 210 and the electrode assembly 400.

[0058] For example, when two electrode terminals 230 are connected to the cover plate body 210, the two electrode terminals 230 are located on opposite sides of the explosion-proof valve 240 along the first direction. In this case, two first protrusions 222 can be formed on the insulating body 221, each corresponding to one of the two electrode terminals 230. When one electrode terminal 230 is connected to the cover plate body 210, one first protrusion 222 can be formed on the insulating body 221, or two first protrusions 222 can be formed. One of the two first protrusions 222 is located along the first direction on the side of the electrode terminal 230 away from the explosion-proof valve 240, and the other can be located along the first direction on the side of the explosion-proof valve 240 away from the electrode terminal 230.

[0059] For example, the first protrusion 222 may be integrally formed with the insulating body 221 and connected by bonding, riveting, hot-melt connection, plugging, snapping or fastening.

[0060] For example, the two openings of the airflow sub-channel 520 are respectively located on the two side walls of the first protrusion 222 arranged along the first direction. The airflow sub-channel 520 communicates with the airflow space 510 through an opening near the explosion-proof valve 240.

[0061] For example, such as Figure 4 Vent opening 531 is provided on the surface of insulating body 221 near cover plate body 210 (hereinafter referred to as the top surface of insulating body 221). The orthographic projection of vent opening 531 along the height direction of battery cell onto cover plate body 210 can coincide with explosion-proof valve 240, be located inside explosion-proof valve 240, or extend beyond the outer contour of explosion-proof valve 240. Lower insulating member 220 forms exhaust channel 530. The opening of exhaust channel 530 on the top surface of insulating body 221 forms vent opening 531. When the bottom surface of insulating body 221 forms a second protrusion 223 corresponding to explosion-proof valve 240, the other opening of exhaust channel 530 is located on the circumferential sidewall of second protrusion 223 (i.e., the two sidewalls of second protrusion 223 that are arranged opposite each other along the first direction, and the two sidewalls that are arranged opposite each other along the thickness direction of battery cell) and / or on the bottom surface of second protrusion 223. The explosion-proof valve 240 is connected to the exhaust passage 530 through the vent opening 531, and the exhaust passage 530 is connected to the airflow space 510 through another opening.

[0062] For example, Figure 5 A partial cross-sectional diagram of a battery cell with the fourth structure is shown. (For example...) Figure 5The opening of the exhaust passage 530 on the top surface of the insulating body 221 forms a ventilation opening 531. When the second protrusion 223 is not provided on the bottom surface of the insulating body 221 at the position corresponding to the explosion-proof valve 240, the other opening of the exhaust passage 530 is located on the bottom surface of the insulating body 221.

[0063] For example, a battery cell may be provided with two adapters 600, one adapter 600 electrically connecting the positive terminal to the positive electrode tab, and the other adapter 600 electrically connecting the negative terminal to the negative electrode tab.

[0064] For example, the protrusion structure 700 can be connected to the adapter 600 by means of integral molding, adhesive bonding, welding, riveting, hot pressing or fastener connection.

[0065] For example, the protruding structure 700 can be a structure formed by bending, stamping, or casting the adapter 600; or, the protruding structure 700 can be a structural component that is independent of and connected to the adapter 600, such as insulating adhesive, hot melt adhesive, support structure, buffer structure, etc. When the protruding structure 700 is made of insulating or hot melt adhesive, it can be heated to a molten state and then connected to the adapter 600 to form the protruding structure 700; when the protruding structure 700 is made of support structure or buffer structure, it can be an independent support block, elastic element, or other structure.

[0066] Figure 6 A partial cross-sectional diagram of a battery cell with the third structure during thermal runaway is shown.

[0067] by Figure 6 Taking the structure and orientation shown as an example, the electrode body 410 expands upwards while generating high-temperature gas. When the electrode body 410 contacts the protruding structure 700 in the airflow space 510, the protruding structure 700 can limit the electrode body 410, preventing it from further encroaching on the airflow space 510. At this time, a gap still exists between the electrode body 410 and the adapter 600 along the height direction of the battery cell (hereinafter referred to as the adapter gap). Combined with... Figure 6 and Figure 7 When the high-temperature gas enters the airflow space 510 from the airflow sub-channel 520, the high-temperature gas can at least bypass the protruding structure 700 and reach the ventilation opening 531 through the transition gap, and finally be discharged through the opened explosion-proof valve 240.

[0068] It should also be noted that the first protrusion 222 can also limit the upward expansion of the electrode body 410. Under the support of the first protrusion 222, the airflow sub-channel 520 located inside the first protrusion 222 can be prevented from being squeezed by the electrode body 410, ensuring that the high temperature gas can smoothly enter the airflow sub-channel 520 through the side gap, and enter the airflow space 510 after passing through the airflow sub-channel 520.

[0069] In this embodiment, the battery cell adapter 600 has a protruding structure 700 on its surface near the electrode assembly 400, protruding towards the electrode assembly 400. When the electrode body 410 expands or moves towards the cover assembly 200, the electrode body 410 will preferentially contact the protruding structure 700 instead of directly contacting the adapter 600. The protruding structure 700 can prevent the electrode body 410 from continuing to move upward or expand, ensuring that a gap for gas flow is maintained between the opposing surfaces of the electrode body 410 and the adapter 600. After flowing out from the gas flow sub-channel 520, the gas can smoothly pass through the gas flow space 510 through the aforementioned gap and flow to the explosion-proof valve 240 through the vent opening 531. The space between the adapter 600 and the insulating body 221 is limited. When the electrode body 410 contacts the adapter 600, the exhaust efficiency is low. The protruding structure 700, by preventing the electrode body 410 from moving upward or expanding further, can increase the space between the electrode body 410 and the insulating body 221, thereby improving the exhaust efficiency. In this embodiment, when the electrode body 410 expands or moves, the gas in the containment space 300 can still flow smoothly in the airflow channel 500 in a timely manner, and can eventually pass through the explosion-proof valve 240 to be discharged from the battery cell, which helps to improve the exhaust efficiency and safety performance of the battery cell.

[0070] like Figure 4 and Figure 7 In some embodiments, the adapter 600 is welded to the electrode terminal 230 and a solder mark 610 is formed between them, and the protrusion structure 700 at least partially covers the solder mark 610; along the first direction, the tab 420 and the first protrusion 222 are spaced apart, and the minimum distance between the tab 420 and the adjacent first protrusion 222 is L1, and the dimension of the lower insulating member 220 along the first direction (hereinafter referred to as the length of the lower insulating member 220) is L, 2mm < L1 ≤ L / 5.

[0071] For example, along the height direction of the battery cell, the orthographic projection of the protrusion 700 onto the adapter 600 may partially coincide with, be located within, or completely cover the solder mark 610.

[0072] For example, the adapter 600 is bent to form a raised structure 700 to at least partially cover the solder mark 610; or, it is bonded to the adapter 600 with insulating adhesive or hot melt adhesive to form a raised structure 700 to at least partially cover the solder mark; or, it is snapped onto the adapter 600 with a support block or elastic member to form a raised structure 700 to at least partially cover the solder mark 610.

[0073] It should be noted that the edge of the tab 420 near the first protrusion 222 may not be parallel to the side wall of the first protrusion 222 near the tab 420 (hereinafter referred to as the inner side wall of the first protrusion 222). That is, the distance between different areas of the tab 420 and the first protrusion 222 along the first direction may be different. In this embodiment, L1 represents the minimum distance value.

[0074] When impurities on the solder mark 610 separate from the solder mark 610 due to shaking, since the raised structure 700 at least partially covers the solder mark 610, the impurities can be blocked by the raised structure 700, reducing the risk of impurities falling into the electrode body 410, preventing internal short circuits in the electrode assembly 400, and helping to improve the safety performance of the battery cell.

[0075] At the same time, combined Figure 4 It can be seen that during the process of gas flowing from the gas flow sub-channel 520 to the explosion-proof valve 240, it is also affected by the tab 420. That is to say, when the gas flows in the gas flow space 510, it not only needs to bypass the protruding structure 700, but also needs to bypass part of the tab 420.

[0076] In view of this, in this embodiment, the tab 420 and the first protrusion 222 are spaced apart along the first direction, so that there is space for smooth gas flow between the tab 420 and the opening of the airflow sub-channel 520 near the tab 420 (hereinafter referred to as the outlet of the airflow sub-channel 520). This allows the gas to flow out of the outlet of the airflow sub-channel 520 and smoothly bypass the tab 420, reducing the obstruction of the airflow by the tab 420 and improving the exhaust efficiency of the battery cell.

[0077] However, the distance between the first protrusion 222 and the tab 420 along the first direction also needs to be specifically designed.

[0078] Because the length of the lower insulating component 220 is limited, if L1 is too large, the tab 420 will be too close to the explosion-proof valve 240 along the first direction. In this case, the tab 420 will obstruct the airflow to the exhaust channel 530, causing gas to accumulate here and not be able to be discharged smoothly through the explosion-proof valve 240. At the same time, when the same cover plate body 210 is connected to both the positive and negative terminals, an excessively large L1 will also cause the center distance between the positive and negative tabs to be too small, resulting in an excessively concentrated current density, which is not conducive to heat dissipation of the battery cell.

[0079] If L1 is too small, the tab 420 will still significantly obstruct the airflow through the outlet of the airflow sub-channel 520. At the same time, when assembling some battery cells, tape will be applied to the tab 420. If L1 is too small, the tape will interfere with the inner wall of the first protrusion 222 and block the outlet of the airflow sub-channel 520.

[0080] To avoid the above problems, in this embodiment, L1 is designed to be 2mm < L1 ≤ L / 5. On the one hand, this ensures that the tab 420 is located in a reasonable position within the airflow space 510, while reducing the obstruction of the tab 420 to the airflow entering or leaving the airflow space 510. This helps to ensure that the gas can flow smoothly at various positions within the airflow channel 500, which helps to improve the exhaust efficiency of the battery cell. On the other hand, when the cover plate body 210 is connected to the positive and negative terminals, it also ensures that the center distance between the positive and negative tabs is reasonable, which helps to dissipate heat from the battery cell.

[0081] like Figure 4 and Figure 7 In some embodiments, the first protrusion 222 has an inner wall close to the tab 420. The orthographic projection of the tab 420 along the first direction onto the inner wall of the first protrusion 222 is the tab projection. The tab projection does not completely block the opening of the airflow sub-channel 520 located on the inner wall of the first protrusion 222 (i.e., the outlet of the airflow sub-channel 520).

[0082] For example, the tab projection may partially block the outlet of the airflow sub-channel 520; or, the tab projection may not block the outlet of the airflow sub-channel 520.

[0083] It should be noted that when the tab projection obstructs the outlet portion of the airflow sub-channel 520, the obstructed portion includes a portion along the thickness direction of the battery cell and may also include a portion along the height direction of the battery cell. In some embodiments, the tab 420 has a multi-layer structure, and the tab projection in this case can also be a similar multi-layer structure, and does not necessarily have to be a closed pattern.

[0084] Combination Figure 7 The structure and orientation shown are explained. Figure 7 The airflow sub-channel 520, located in the upper left position, is partially obstructed by the tab projection at its outlet. Understandably, the tab projection and the outlet of the airflow sub-channel 520 also partially obstruct each other along the height of the battery cell. Therefore, the gas flowing out from this part needs to bypass the tab 420 to continue flowing within the airflow space 510. However, the lower part of the outlet of the airflow sub-channel 520 is not obstructed by the tab projection. The gas flowing out from this part is not affected by the tab 420 during its flow along the first direction, and the flow path of this part of the gas is shorter.

[0085] Therefore, by designing the tab projection to not completely block the outlet of the airflow sub-channel 520, this embodiment allows some of the gas flowing out of the outlet of the airflow sub-channel 520 to flow in a straight line along the first direction in the airflow space 510 without being blocked by the tab 420. This can shorten the gas flow path and help improve the exhaust efficiency of the battery cell.

[0086] like Figure 7 In some embodiments, the maximum dimension of the airflow sub-channel 520 along the thickness direction of the battery cell is W1, and the maximum dimension of the overlapping portion of the tab projection and the opening of the airflow sub-channel 520 along the thickness direction of the battery cell is W2, where W2≤W1×2 / 3.

[0087] If W2 is too large, it means that the area of ​​the outlet of the airflow sub-channel 520 overlapping with the projection of the electrode is large. In this case, a large part of the gas flowing out of the outlet of the airflow sub-channel 520 will be blocked by the electrode 420, which will result in low exhaust efficiency of the battery cell.

[0088] In some embodiments, the internal space design of the battery cell in the height direction is relatively compact. Therefore, compared to adjusting the overlap between the tab projection and the opening of the airflow sub-channel 520 in the height direction of the battery cell to achieve a better exhaust effect, it is simpler to adjust the overlap between the tab projection and the opening of the airflow sub-channel 520 in the thickness direction of the battery cell. Therefore, in this embodiment, W2 is designed to be W2≤W1×2 / 3, which allows a larger portion of the gas flowing out of the outlet of the airflow sub-channel 520 to flow linearly in the first direction within the airflow space 510 without being obstructed by the tab 420, thus helping to achieve a higher exhaust efficiency of the battery cell. At the same time, it prevents the tab 420 from extending too far in the thickness direction of the battery cell, thus avoiding interference with the arrangement of the protrusion structure 700.

[0089] like Figure 7 In some embodiments, a rounded chamfer 421 with radius r is formed between the side edge of the tab 420 near the first protrusion 222 and the free end of the tab 420, where 5mm≤r≤10mm.

[0090] For example, r can be 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm or 10mm.

[0091] For example, a rounded chamfer 421 may also be formed between the side edge of the tab 420 away from the first protrusion 222 and the free end of the tab 420.

[0092] It should be noted that one end of the tab 420 is integrally connected to the electrode plate in the electrode body 410, and the other end extends out of the electrode body 410. The end of the tab 420 that extends out of the electrode body 410 is the free end of the tab 420. When assembling the battery cell, the part of the tab 420 near the free end will be welded to the adapter 600.

[0093] by Figure 7 Taking the structure and direction shown as an example, when the gas flowing out of the outlet of the airflow sub-channel 520 encounters the tab 420, it will flow along the side wall of the tab 420 near the first protrusion 222 towards the free end of the tab 420. When the gas flows to the free end, it is blocked by the tab 420, and the gas needs to change its flow direction to bypass the obstruction and continue to flow. In other words, some gas needs to bypass the free end of the tab 420 and flow towards the ventilation opening 531.

[0094] If there is no smooth transition between the free end of the tab 420 and the side edge of the tab 420 near the first protrusion 222, for example, forming a right angle or near-right angle, then the gas needs to bypass the right angle when turning from the side wall of the tab 420 to the free end. This not only results in a longer flow path but also causes gas to accumulate at this point, affecting the gas flow in the nearby area and reducing exhaust efficiency. If a rounded chamfer 421 is formed between the two, then the gas can be smoothly turned from the side wall of the tab 420 to the free end of the tab 420 along the rounded chamfer 421. At the same time, the flow path of the gas bypassing the rounded chamfer 421 is shorter, which helps to improve the exhaust efficiency of the battery cell.

[0095] Of course, the radius r of the chamfer 421 also needs to be designed. If r is too small, on the one hand, the chamfer 421 will be close to a right angle, and the effect of smooth gas diversion and reducing flow path will not be obvious. On the other hand, a chamfer 421 with a small radius will also have the problem of greater processing difficulty. If r is too large, then the area of ​​the tab 420 near the free end will be too small in the first direction. When this area of ​​the tab 420 is welded to the adapter 600, the redundancy of the welding area in the first direction will also be too small. The connection area between the tab 420 and the adapter 600 is too small, which will not only lead to poor welding quality between the tab 420 and the adapter 600, but also affect the current flow area of ​​the tab 420, resulting in poor performance of the battery cell.

[0096] To avoid the above problems, in this embodiment, r is designed to be 5mm≤r≤10mm. On the one hand, this allows the gas to bypass the tab 420 more smoothly and with a shorter flow path, which is beneficial to improving the exhaust efficiency of the battery cell. On the other hand, it also ensures that there is a large contact area between the tab 420 and the adapter 600, which not only helps to improve the welding quality between the two, but also helps to increase the current flow area of ​​the tab 420, thereby improving the electrical performance of the battery cell.

[0097] like Figure 7 In some embodiments, the same adapter 600 is connected to two tabs 420, the two tabs 420 are spaced apart along the thickness direction of the battery cell, and the minimum spacing distance is W3. The dimension of the lower insulating member 220 along the thickness direction of the battery cell is W, where W / 3≤W3≤W×2 / 3.

[0098] by Figure 7 The structure and orientation shown are used as an example for explanation. For the adapter 600 on the left, of the two tabs 420 connected to it, one is located on top and the other is located on the bottom. Each tab 420 includes one or a group of multilayer tabs led out from the electrode body 410.

[0099] After the two tabs 420 are welded to the adapter 600, it is difficult to align the free ends of different layers of tabs within the same tab 420. This prevents the free ends of the same tab 420 from forming a plane perpendicular to the bottom surface of the adapter 600, meaning that the multiple layers of tabs may be misaligned. Understandably, the spacing between different regions of the free ends of the two tabs 420 along the thickness direction of the battery cell will be different. In this embodiment, W3 represents the minimum spacing between the free ends of the two tabs 420.

[0100] Connecting two tabs 420 to the same adapter 600 can improve the space utilization of the housing space 300, which helps to improve the energy density of the battery cell.

[0101] However, if W3 is too small, it means that the two tabs 420 are too close together along the thickness direction of the battery cell. During battery cell assembly, if the tabs 420 deform, they may overlap. This can lead to welding abnormalities (e.g., using ultrasonic welding) during the welding process, affecting the welding and pressing effect and increasing the likelihood of foreign matter buildup. Simultaneously, the gas flowing within the airflow space 510 needs to pass through the gap between the two tabs 420 when bypassing them. If the two tabs 420 are too close, the space for gas flow will be too small, hindering proper venting from the battery cell. Furthermore, the close proximity of the two tabs 420 will cause more concentrated heat generation at the tabs 420 during battery cell operation, which is detrimental to battery cell performance and safety.

[0102] Combination Figure 7In the thickness direction of the battery cell, the adapter 600 is located in the middle of the lower insulator 220. If W3 is too large, the two tabs 420 will be too far from the middle of the lower insulator 220, resulting in a small overlap area between each tab 420 and the adapter 600. When welding the tabs 420 and the adapter 600, the welding area will also be too small, leading not only to poor welding quality between the tabs 420 and the adapter 600 but also affecting the current-carrying area of ​​the tabs 420, resulting in poor performance of the battery cell.

[0103] To avoid the above problems, in this embodiment, W3 is designed as W / 3≤W3≤W×2 / 3. On the one hand, this can ensure the welding quality between the tab 420 and the adapter 600, which helps to improve the electrical and safety performance of the battery cell. On the other hand, it can also ensure that the gas can flow smoothly in the airflow space 510 through the gap between the two tabs 420, which helps to improve the exhaust efficiency of the battery cell.

[0104] like Figure 7 In some embodiments, the protruding structure 700 is a gel. Along the height direction of the battery cell, the orthographic projection of the protruding structure 700 on the adapter 600 is a support projection. The solder mark 610 is located within the support projection. The minimum distance between the edge of the support projection and the edge of the adjacent solder mark 610 is D, where D ≥ 1 mm. That is, the minimum distance D between each point on the solder mark 610 and the edge of the protruding structure 700 on the adapter 600 is ≥ 1 mm.

[0105] For example, the supporting projection can be a circle, a semicircle, a polygon, or an irregular shape.

[0106] For example, the shape of the solder mark 610 can be circular, semi-circular, polygonal, or irregular (e.g., multiple intersecting or non-intersecting line-like patterns, or a spiral-like pattern formed within a generally circular area).

[0107] For example, the colloid can be an insulating adhesive, a hot melt adhesive, etc. During manufacturing, the colloid material can be heated to a molten state and then bonded to the adapter 600 to form a raised structure 700.

[0108] When the raised structure 700 is a gel, the connection structure is simpler and easier to manufacture compared to welding, fastening, or snap-fit ​​connections between the raised structure 700 and the adapter 600. Furthermore, when the raised structure 700 is formed by adding support blocks and elastic elements before connecting it to the adapter 600, different shapes of support blocks and elastic elements need to be designed and manufactured for different solder marks 610 shapes. Since the raised structure 700 is a gel, it can accommodate more shapes of solder marks 610. The gel becomes fluid when heated to a molten state, allowing it to be flexibly placed on the adapter 600 to cover the solder mark 610 according to its actual shape, facilitating the design and manufacturing of the battery cell. With the solder mark 610 located within the support projection, meaning the raised structure 700 can completely cover its corresponding solder mark 610, the raised structure 700 can block all foreign particles separating from the solder mark 610, providing good protection against welding foreign objects. Based on the foregoing, it can be understood that the protruding structure 700 acts as a limit for the upward expansion or movement of the electrode body 410. When the electrode body 410 presses against the protruding structure 700, if the pressure on the protruding structure 700 is too high, there is a risk of failure. Specifically, since the area where the solder mark 610 is set is small, if D is too small, the area of ​​the support projection will be similar to the area where the solder mark 610 is set, resulting in a small support projection area. Consequently, the contact area between the protruding structure 700 and the electrode body 410 is too small, and the pressure on the protruding structure 700 when it is pressed will be too high, making the protruding structure 700 more prone to failure under pressure. This reduces or eliminates the support function of the protruding structure 700, thereby reducing exhaust efficiency.

[0109] To avoid the above problems, in this embodiment, D is designed to be D≥1mm. On the one hand, this can ensure that the protruding structure 700 can provide reliable foreign object protection for the solder mark 610. On the other hand, it can ensure that the support projection has a large area to reduce the pressure on the protruding structure 700 when supporting the electrode body 410, reduce the failure probability of the protruding structure 700, and help improve the venting effect of the battery cell.

[0110] In some embodiments, the first protrusion 222 has an inner wall close to the protrusion structure 700. The orthographic projection of the protrusion structure 700 along the first direction onto the inner wall of the first protrusion 222 is the protrusion projection. The protrusion projection does not completely block the outlet of the airflow sub-channel 520. It should be understood that the protrusion projection may partially block the outlet of the airflow sub-channel 520; or, the protrusion projection may not block the outlet of the airflow sub-channel 520. In this case, at least a portion of the gas flowing out from the outlet of the airflow sub-channel 520 can flow directly through the airflow space 510 to the explosion-proof valve 240 without bypassing the protrusion structure 700, which is beneficial for improving the exhaust effect of the battery cell.

[0111] like Figure 4In some embodiments, along the height direction of the battery cell, the protrusion structure 700 does not extend beyond the surface of the first protrusion 222 that is away from the insulating body 221 (hereinafter referred to as the bottom surface of the first protrusion 222).

[0112] For example, when the bottom surface of the first protrusion 222 is not planar, the protrusion structure 700 does not exceed the lowest point of the bottom surface of the first protrusion 222 along the height direction of the battery cell.

[0113] by Figure 4 The structure and orientation shown are used as examples for explanation. Figure 4 The first protrusion 222 on the right and the adjacent protrusion structure 700, the bottom surface of the first protrusion 222 abuts against the top surface of the electrode body 410, while the bottom surface of the protrusion structure 700 is spaced apart from the top surface of the electrode body 410, that is, the entire protrusion structure 700 does not extend beyond the bottom surface of the first protrusion 222.

[0114] In the battery cell, the bottom surface of the first protrusion 222 of the lower insulating member 220 needs to abut against the top surface of the electrode body 410 to limit the electrode body 410 and ensure that the electrode body 410 can maintain a preset position within the accommodating space 300.

[0115] However, if the protruding structure 700 extends beyond the bottom surface of the first protrusion 222 along the height direction of the battery cell, then the electrode body 410 will already be in contact with the protruding structure 700 before contacting the bottom surface of the first protrusion 222. Due to the obstruction of the protruding structure 700, the electrode body 410 cannot reliably contact the bottom surface of the first protrusion 222. Because the contact area between the protruding structure 700 and the electrode body 410 is small, it is difficult to achieve stable positioning of the electrode body 410 solely through the protruding structure 700, thus affecting the structural stability of the battery cell.

[0116] To avoid the above problems, in this embodiment, the protrusion structure 700 does not extend beyond the bottom surface of the first protrusion 222, and there is no interference between the protrusion structure 700 and the electrode body 410. This ensures that the electrode body 410 can reliably contact the bottom surface of the first protrusion 222, thereby helping to improve the structural stability of the battery cell.

[0117] Figure 8 Showing Figure 4 A schematic diagram of the cross-section AA in the middle.

[0118] like Figure 8 In some embodiments, the thickness of the protrusion structure 700 is H1, and the thickness of the tab 420 is H2, where 100μm < H1 < 2 × H2.

[0119] It should be noted that the thickness of the protruding structure 700 is its dimension along the height direction of the battery cell. The thickness of the protruding structure 700 may be uniform or non-uniform. When the thickness of the protruding structure 700 is non-uniform, H1 is the thickness value corresponding to the area with the maximum thickness of the protruding structure 700.

[0120] It should be noted that the thickness of tab 420 is the sum of the thickness values ​​(dimensions perpendicular to the surface) of each of the multiple tabs in a single tab 420. H2 refers to the thickness value of the part of tab 420 that is welded to adapter 600.

[0121] If H1 is too small, the gap between the top surface of the electrode body 410 and the bottom surface of the adapter 600 will be small when the protruding structure 700 limits the expansion or movement of the electrode body 410. This will result in a smaller flow space for the gas, which is not conducive to the flow of gas in the airflow space 510. If H1 is too large, the bottom surface of the protruding structure 700 will be too close to the top surface of the electrode body 410. Even if the electrode body 410 does not expand or move, the bottom surface of the protruding structure 700 will easily come into contact with the top surface of the electrode body 410. This could cause the protruding diaphragm in the electrode body 410 to be compressed, resulting in wrinkles or damage, which could lead to an internal short circuit in the electrode assembly 400.

[0122] To avoid the above problems, in this embodiment, H1 is designed to be 100μm < H1 < 2×H2. This ensures that when the electrode body 410 expands or moves, a large gap is maintained between the top surface of the electrode body 410 and the bottom surface of the adapter 600, so as to ensure that the gas can flow smoothly in the airflow space 510, thereby improving the exhaust efficiency of the battery cell. At the same time, when the electrode body 410 does not expand or move, the bottom surface of the protrusion structure 700 is kept at a distance from the top surface of the electrode body 410, reducing the risk of internal short circuit caused by the electrode body 410 being pressed by the protrusion structure 700.

[0123] Based on the same inventive concept and in conjunction with the description of the battery cells in the above embodiments, this embodiment provides a battery that has the corresponding technical effects of the battery cells in the above embodiments, which will not be repeated here.

[0124] A battery comprising a battery cell as described in the various embodiments above.

[0125] It should be noted that some embodiments of this application have been described above. Other embodiments are within the scope of the appended claims.

[0126] The various embodiments in this application are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0127] The description in this application is given for illustrative purposes and is not intended to be exhaustive or to limit the application to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described to better illustrate the principles and practical application of this application and to enable those skilled in the art to understand this application and design various embodiments with various modifications suitable for a particular purpose.

[0128] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application is limited to these examples; under the concept of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0129] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0130] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A battery cell, characterized in that, include: A housing having at least one open end; An electrode assembly includes an electrode body and tabs extending from the electrode body; A cover plate assembly is fitted onto the opening end and, together with the housing, forms a receiving space for accommodating the electrode assembly; the cover plate assembly includes a cover plate body and a lower insulating member; The cover plate body is provided with electrode terminals and explosion-proof valves spaced apart along a first direction, the first direction intersecting with the thickness direction of the battery cell; The lower insulating member is connected to the side of the cover plate body near the electrode assembly. The lower insulating member includes an insulating body. A first protrusion protruding toward the electrode assembly is formed on the surface of the insulating body away from the cover plate body. The first protrusion is located on the side of the electrode terminal away from the explosion-proof valve along the first direction. The first protrusion forms an airflow sub-channel that extends along the first direction. The insulating body forms a venting opening corresponding to the explosion-proof valve. The portion of the insulating body located between the first protrusion and the venting opening defines an airflow space with the electrode body. The airflow sub-channel, the airflow space, and the venting opening are sequentially connected to form an airflow channel. An adapter is disposed within the airflow space, and the electrode tab is electrically connected to the electrode terminal through the adapter; the surface of the adapter near the electrode assembly is provided with a protruding structure protruding toward the electrode assembly.

2. The battery cell according to claim 1, characterized in that, The adapter is welded to the electrode terminal and a solder mark is formed between them, with the protruding structure at least partially covering the solder mark; Along the first direction, the tab and the first protrusion are spaced apart, and the minimum distance between the tab and the adjacent first protrusion is L1. The dimension of the lower insulating member along the first direction is L, where 2mm < L1 ≤ L / 5.

3. The battery cell according to claim 2, characterized in that, The first protrusion has an inner wall close to the tab, and the orthographic projection of the tab along the first direction onto the inner wall of the first protrusion is the tab projection. The tab projection does not completely block the opening of the airflow sub-channel located on the inner wall of the first protrusion.

4. The battery cell according to claim 3, characterized in that, The maximum dimension of the airflow sub-channel along the thickness direction of the battery cell is W1, and the maximum dimension of the overlapping portion of the tab projection and the opening of the airflow sub-channel along the thickness direction of the battery cell is W2, where W2≤W1×2 / 3.

5. The battery cell according to claim 2, characterized in that, A rounded chamfer with radius r is formed between the side edge of the electrode near the first protrusion and the free end of the electrode, where 5mm≤r≤10mm.

6. The battery cell according to claim 2, characterized in that, The same adapter is connected to two tabs, which are spaced apart along the thickness direction of the battery cell, with a minimum spacing of W3. The dimension of the lower insulating member along the thickness direction of the battery cell is W, where W / 3≤W3≤W×2 / 3.

7. The battery cell according to claim 2, characterized in that, The protruding structure is a gel, and along the height direction of the battery cell, the orthographic projection of the protruding structure on the adapter is a support projection. The solder mark is located within the support projection, and the minimum interval distance between the edge of the support projection and the edge of the adjacent solder mark is D, where D≥1mm.

8. The battery cell according to claim 1, characterized in that, Along the height direction of the battery cell, the protrusion structure does not extend beyond the surface of the first protrusion that is away from the insulating body.

9. The battery cell according to claim 1, characterized in that, The thickness of the protrusion structure is H1, and the thickness of the tab is H2, where 100μm < H1 < 2 × H2.

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

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