battery

Abstract

The utility model provides a kind of battery, the tab of the battery adopts the sectional type construction of foundation part and extension part connection, wherein the width of extension part in second direction is less than foundation part, and width gradient is formed.The width gradient constitutes bending induction zone in mechanics, so that it preferentially bends in the root of extension part, avoids tab root bending tear and leads to tab reverse insertion problem.In the same tab group, in the direction of pointing to first central surface, the length of at least part tab foundation part in third direction presents increasing trend, i.e.the bending point of tab in different positions is staggered in the direction of pointing to first central surface in ladder type order, effectively avoids the bending interference problem of tab, ensures tab deformation in the direction of away from pole piece, eliminates the risk of tab reverse insertion extrusion isolation film, significantly improves battery assembly yield and long-term safety.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a battery. Background Technology

[0002] Currently, in the manufacturing of prismatic batteries, the cell tabs need to be welded to the adapter plate and then rotated 90° to fit the cell into the casing. This rotation process can easily cause the base of the tabs to be inserted upside down, squeezing the separator and the electrode, causing damage to the separator, and significantly increasing the risk of short circuits in the battery. Utility Model Content

[0003] In view of the above, this application aims to provide a battery that solves some or all of the aforementioned technical problems.

[0004] For the purposes described above, this application provides a battery, comprising: The shell and cover plate form an enclosure space, and the cover plate is connected to the pole post; Two battery cell assemblies are arranged in the receiving space along a first direction. Each battery cell assembly includes an electrode sheet. The electrode sheet extends in the direction toward the cover plate and has a tab. The tabs in the same battery cell assembly move toward the first center surface to form a tab group. The tab group is electrically connected to the terminal post. The electrode tab includes a base portion and an extension portion connected to each other. The base portion is connected to the electrode sheet. The width of the extension portion in the second direction is smaller than the width of the base portion in the second direction. In the same electrode tab group, at least some of the base portions of the electrode tabs show an increasing length trend in the third direction in the direction pointing to the first center surface. The second direction is perpendicular to the first direction. The third direction is the extension direction of the electrode tab and is perpendicular to both the first and second directions. The first center surface is the contact surface of the two battery cell assemblies.

[0005] Furthermore, the electrode group includes multiple electrode subgroups, each electrode subgroup including at least one electrode. The base of the electrodes within the same electrode subgroup has the same height. Within the same electrode group, in the direction pointing towards the first center plane, the length of the base of the multiple electrode subgroups in the third direction shows an increasing trend.

[0006] Furthermore, the electrode includes a first side and a second side disposed opposite to each other in a first direction, the first side being disposed away from the first center surface, the first side being coated with a first coating, and the second side being coated with a second coating. In the third direction, the length of the first coating is greater than the length of the second coating.

[0007] Furthermore, within the same electrode group, in the direction pointing towards the first central surface, the length of the first coating of at least some electrodes exhibits an increasing trend in the third direction.

[0008] Furthermore, the first coating of the electrodes located in the same electrode group has the same length in the third direction. In the same electrode group, in the direction pointing to the first center surface, the length of the first coating of the multiple electrode groups in the third direction shows an increasing trend.

[0009] Furthermore, within the same electrode group, in the direction pointing towards the first central surface, the length of the second coating on at least some of the electrodes exhibits an increasing trend in the third direction.

[0010] Furthermore, the second coatings of electrodes located in the same electrode group have the same length in the third direction. In the same electrode group, the length of the second coatings of multiple electrode groups in the third direction increases in the direction pointing towards the first center surface.

[0011] Furthermore, within the same electrode group, in the direction pointing towards the first central surface, at least some of the electrode base portions exhibit a decreasing trend in width in the second direction.

[0012] Furthermore, the battery cell assembly includes two battery cells, each of which includes two electrodes with opposite polarities and a separator disposed between the two electrodes; In the third direction, the length between the edge of the electrode sheet near the tab and the edge of the separator near the tab is a; in a group of tabs, the length of the base portion of the tab near the first center surface is y1, the length of the base portion of the tab away from the first center surface is y2, a < y1 ≤ 1.5a, 0.5a < y2 ≤ a.

[0013] Furthermore, the length of the first coating is c, and the length of the second coating is b; wherein, 0.1a≤b<a, a≤c≤2a.

[0014] As can be seen from the above, the battery tabs provided in this application adopt a segmented structure with a base and an extension connected together. The width of the extension in the second direction is smaller than that of the base, forming a width gradient. This gradient mechanically constitutes a bending induction zone. By reducing the local cross-sectional modulus, the bending initiation position of each tab during core rotation is precisely controlled, causing it to bend preferentially at the root of the extension rather than at the root of the tab, thus avoiding the tab inversion problem caused by tearing at the root of the tab. Based on this, in the same tab group, in the direction pointing towards the first center plane, the length of the base of at least some tabs in the third direction shows an increasing trend. The outer tabs, being farther from the first center plane, require a larger bending angle, and their shorter bases allow them to enter the narrowing extension earlier, resulting in a lower bending initiation position; the inner tabs have a smaller bending angle, and their longer bases raise the bending initiation position. Therefore, the bending points of the tabs at different positions are staggered in a stepped manner along the direction pointing to the first center plane, which effectively avoids the bending interference problem of the tabs, ensures that the tabs deform in the direction away from the electrode sheet, eliminates the risk of the tabs being inserted backwards and squeezing the separator, and significantly improves the battery assembly yield and long-term safety. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the battery from the front view in an embodiment of this application; Figure 2 This is a top view of the battery in an embodiment of this application; Figure 3 This is a schematic diagram of the structure of two battery cell assemblies in an embodiment of this application; Figure 4 This is a schematic diagram of the electrode sheet structure in an embodiment of this application, wherein the electrode tab is a schematic diagram of the structure of the second side electrode tab; Figure 5 This is a schematic diagram of the electrode sheet structure in an embodiment of this application, wherein the electrode tab is a schematic diagram of the structure of the first side electrode tab; Figure 6a This is a schematic diagram showing the positional relationship between the electrode sheet and the separator in an embodiment of this application, with the tabs on it being the inner tabs closer to the first center surface; Figure 6b This is a schematic diagram showing the positional relationship between the electrode sheet and the separator in an embodiment of this application, with the tabs on it being the outer tabs that are far from the first center surface; Figure 7This is a schematic diagram showing the positional relationship between the first coating, the second coating, and the tab in an embodiment of this application; Figure 8 This is a schematic diagram showing the positional relationship between the first coating, the second coating, and the tabs after grouping in an embodiment of this application; in, Figure 4 , Figure 5 The left pole is a schematic diagram of the inner pole closer to the first central plane, and the right pole is a schematic diagram of the outer pole farther from the first central plane.

[0017] Explanation of reference numerals in the attached figures: 100, Housing; 200, Cover plate; 210, Terminal post; 300, Cell assembly; 310, Cell; 320, Separator; 330, Electrode; 340, Tab; 341, Base section; 342, Extension section; 343, First side surface; 344, Second side surface; 350, First coating; 360, Second coating; 370, Tab assembly; 371, Tab group; X, First direction; Y, Second direction; Z, Third direction; L, First center surface. Detailed Implementation

[0018] 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.

[0019] 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 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 covers the element or object listed following the word and its 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.

[0020] In related technologies, the battery structure mainly consists of a casing and a cover plate forming a sealed housing space, with positive and negative electrode posts connected to the cover plate. This housing space can, for example, accommodate two battery cell assemblies, each composed of two battery cells. Each battery cell, as the core energy storage unit, consists of a positive electrode, a negative electrode, and a separator, and can be manufactured using a winding or stacking process. Each battery cell's positive and negative electrode extends into positive and negative tabs. Tabs of the same polarity within the same battery cell assembly are stacked to form a positive tab group and a negative tab group, achieving parallel current convergence of multiple electrodes.

[0021] The electrical connection between the tab assembly and the terminal can be either direct welding or indirect connection via an adapter plate. In this case, the positive tab assemblies of both battery cells are first welded together to the positive adapter plate, which then connects to the positive terminal of the cover plate. The negative side is connected in the same way. The adapter plate solution can distribute welding stress and improve connection reliability, making it particularly suitable for multi-tab, high-current scenarios. After welding, the battery cell assembly and the adapter plate form a unified electrical connection.

[0022] After welding, the two battery cell assemblies are initially laid out horizontally at 180°. They need to be rotated 90° to be joined together and installed into the casing. During this process, each tab assembly rotates 90° synchronously with the assembly, changing from a horizontally extended state to a vertically bent state. Due to stress concentration at the base of the tabs, the external force during rotation can cause tearing at the base of the tabs, resulting in inverted tab insertion. Alternatively, the tab material may be soft and have limited ductility, leading to random bending positions during rotation. This can easily cause bending interference between adjacent tabs, potentially causing the tabs to bend towards the electrode plate and resulting in inverted tab insertion. Inverted tab insertion can damage the separator and electrode plate, causing separator breakage and contact between the positive and negative electrode plates, significantly increasing the risk of internal short circuits in the battery and restricting product yield and safety performance.

[0023] This application improves the structure of the tabs to overcome the problem of internal short circuits in the battery caused by inverted tab insertion.

[0024] It should be noted that, for ease of description, the arrangement direction of the two battery cell assemblies 300 within the housing 100 is defined as the first direction X, and the direction perpendicular to this arrangement direction is defined as the second direction Y, i.e., the second direction Y is perpendicular to the first direction X. The extension direction of the tab 340 is defined as the third direction Z. In the battery cell assembly 300 assembled within the housing 100, the extension direction of the tab 340 is not vertical or horizontal, but rather extends obliquely along the axis of the battery cell 310, ultimately pointing towards the electrode post 210 of the cover plate 200. The Z direction in the attached figure represents the extension direction of the tab 340 in its unbent state. Furthermore, the contact surface of the two battery cell assemblies 300 is defined as the first center surface L. Specifically, after the two battery cell assemblies 300 are initially in a horizontally unfolded state of 180°, rotate 90° around the second direction Y to complete the core bonding, the symmetrical interface formed by their contact is the first center surface L.

[0025] The following describes specific embodiments in conjunction with... Figures 1-8 The technical solution of this application will be described in detail below.

[0026] In view of this, such as Figures 1-5 As shown, in some embodiments, a battery includes: a housing 100 and a cover plate 200, forming an accommodating space, the cover plate 200 being connected to a terminal post 210; two cell assemblies 300, arranged in the accommodating space along a first direction X, each cell assembly 300 including an electrode 330, the electrode 330 extending in the direction toward the cover plate 200 having a tab 340, the tabs 340 in the same cell assembly 300 approaching a first central surface L to form a tab group 370, the tab group 370 being electrically connected to the terminal post 210.

[0027] The electrode tab 340 includes a base portion 341 and an extension portion 342 connected to each other. The base portion 341 is connected to the electrode plate 330. The width of the extension portion 342 in the second direction Y is smaller than the width of the base portion 341 in the second direction Y. In the same electrode tab group 370, in the direction pointing to the first center plane L, at least some of the base portions 341 of the electrode tab 340 show an increasing trend in length in the third direction Z.

[0028] Specifically, the tab 340 adopts a segmented structure, including a base portion 341 directly connected to the electrode 330 and an extension portion 342 for connecting to the pole post 210. The base portion 341 maintains a width comparable to the electrode 330 to ensure current carrying capacity, while the extension portion 342 is narrower than the base portion 341, forming a width abrupt change zone at the connection point. This width gradient design mechanically constitutes a bending induction zone (i.e., the root of the extension portion 342), precisely controlling the bending initiation position of each tab 340 during core rotation by reducing the local section modulus. Compared to the uncontrollable bending point caused by the uniform stiffness of equal-width tabs 340, this structure guides bending behavior through geometric weakening design, causing the tabs 340 to preferentially undergo orderly deformation at the root of the extension portion 342, rather than random bending.

[0029] For example, when the tabs 340 have a uniform width, the random bending occurs at the root of the tabs 340. Because the stress at the root of the tabs 340 is greater, it may cause the root of the tabs 340 to tear, resulting in the torn root of the tabs 340 being inserted upside down into the separator 320, causing damage to the separator 320. By improving the structure of the tabs 340 to have a width gradient design with a base portion 341 and an extension portion 342, the structural strength of the root of the extension portion 342 will be weaker than that of the root of the tabs 340. That is, the root of the extension portion 342 is more likely to bend and deform than the root of the tabs 340. Thus, the problem of the tabs 340 being inserted upside down due to bending and tearing at the root of the tabs 340 is avoided.

[0030] For example, such as Figure 4 , Figure 5 As shown, the width of the base portion 341 in the second direction Y is y, and the width of the extension portion 342 in the second direction Y is z, where 2.5z ≥ y ≥ 1.2z. This ratio range is set based on a balance between bending processability and current carrying reliability. If y / z is less than 1.2 (i.e., the base portion 341 is too narrow), the cross-sectional area for connection with the electrode 330 is insufficient, resulting in excessively high current carrying density and increased temperature rise at the root of the tab 340. At the same time, the connection strength is weakened, making it easy for the root of the tab 340 to break during core bending. Conversely, if the y / z ratio is greater than 2.5 (i.e., the base portion 341 is too wide), the abrupt change in width between the base portion 341 and the extension portion 342 is too large, making it easy for micro-cracks to form at the root of the extension portion 342 during bending. An excessively wide base portion 341 will also increase the overall stiffness of the tab 340, weakening the bending-inducing effect of the width gradient design, making it difficult for the tab 340 to deform in an orderly manner at the predetermined position, and may even interfere with adjacent tabs 340 due to occupying too much space, affecting the compact arrangement and energy density of the tab assembly 370. Therefore, constraining the y / z ratio between 1.2 and 2.5 can ensure the bending flexibility and structural safety of the tab 340 while guaranteeing mechanical strength and electrical connection reliability. This ratio can be flexibly adjusted within the preferred range according to the cell capacity 310, current carrying requirements, and the number of tabs 340.

[0031] Specifically, in the same electrode group 370, along the arrangement direction pointing towards the first central plane L, at least some of the base portions 341 of the electrodes 340 exhibit an increasing gradient in length along the third direction Z (the extension direction of the electrode 340), that is, the electrode 340 closer to the outer edge (the electrode 340 farther from the first central plane L, i.e., ...) Figure 3 , Figure 4 , Figure 5 The base portion 341 of the right-side tab 340 is shorter, and the tab 340 closer to the inner side (the tab 340 closer to the first central surface L, i.e.) Figure 3 , Figure 4 , Figure 5The left-hand tab 340 has a longer base section 341. This gradient layout is highly compatible with the rotational kinematics of the core: because the outer tab 340 is farther from the axis of rotation, its trajectory arc length is greater and the bending angle required is more significant. The shorter base section 341 allows it to enter the narrowing extension section earlier, and the bending starting position is correspondingly lower. The inner tab 340 has a smaller trajectory arc length and a gentler bending angle. Its longer base section 341 raises the starting position of the extension section 342. Thus, the bending points of the tabs 340 at different positions are staggered in a stepped manner along the direction pointing towards the first center plane L, forming a non-interference arrangement in space. This regular bending path ensures that the tabs 340 deform in a direction away from the electrode 330, eliminating the mechanical possibility of the tabs 340 being inserted backwards and damaging the separator 320, and avoiding the risk of short circuits in the positive and negative electrodes 330.

[0032] It should be noted that even if only some of the tabs 340 have their bending points staggered in a stepped manner along the direction pointing to the first center plane L, this will still have a significant guiding effect on adjacent tabs 340. Specifically, all tabs 340 are provided with a base portion 341 and an extension portion 342, and have a bending induction zone formed by a width gradient (i.e., the root of the extension portion 342). Based on this, when some tabs 340 (such as the spaced tabs 340 located in key positions) achieve a stepped bending point distribution through the length difference of the base portion 341, these tabs 340 will undergo regular deformation during the rotation of the core, thereby constraining the random deformation tendency of adjacent tabs 340 and making the bending behavior of the entire tab group 370 tend to be synchronous and orderly.

[0033] Furthermore, the widths of the base portion 341 and the extension portion 342 both exhibit a decreasing trend in the third direction Z (the extension direction of the tab 340). For example, both the base portion 341 and the extension portion 342 are isosceles trapezoids. This gradual width design allows the tab 340 to form a continuous cross-sectional contraction along the extension direction. During core bending, stress can be evenly distributed along the hypotenuse of the trapezoid, avoiding tearing or breakage caused by stress concentration at abrupt width changes. Compared to a rectangular cross-section, the isosceles trapezoidal structure has superior mechanical compliance during bending. Its two hypotenuses naturally guide the tab 340 to deform according to a predetermined curvature, reducing bending resistance while maintaining sufficient current-carrying cross-sectional area. Thus, while improving bending reliability, it also considers the conductivity and structural strength of the tab 340.

[0034] In this embodiment, the battery tabs 340 adopt a segmented structure in which a base portion 341 and an extension portion 342 are connected. The width of the extension portion 342 in the second direction Y is smaller than that of the base portion 341, forming a width gradient. This gradient mechanically constitutes a bending induction zone. By reducing the local section modulus, the bending initiation position of each tab 340 during core rotation is precisely controlled, causing it to bend preferentially at the root of the extension portion 342 rather than at the root of the tab 340, thus avoiding the problem of tab 340 being inserted backwards due to bending and tearing at the root of the tab 340. Based on this, in the same tab group 370, in the direction pointing to the first center plane L, the length of the base portion 341 of at least some tabs 340 shows an increasing trend in the third direction Z. Because the outer tab 340 is farther from the first center plane L and requires a larger bending angle, its shorter base 341 allows it to enter the narrowing extension section earlier, resulting in a lower bending starting position. The inner tab 340 has a smaller bending angle, and its longer base 341 raises the bending starting position. Therefore, the bending points of the tabs 340 at different positions are staggered in a stepped manner along the direction pointing towards the first center plane L, effectively avoiding bending interference problems of the tabs 340, ensuring that the tabs 340 deform away from the electrode sheet 330, eliminating the risk of the tabs 340 being inserted backwards and squeezing the separator 320, and significantly improving battery assembly yield and long-term safety.

[0035] In some embodiments, such as Figure 8 As shown, the electrode group 370 includes multiple electrode subgroups 371, each electrode subgroup 371 includes at least one electrode 340, the base portion 341 of the electrode 340 within the same electrode subgroup 371 has the same height, and in the same electrode group 370, in the direction pointing to the first center plane L, the length of the base portion 341 of the multiple electrode subgroups 371 in the third direction Z shows an increasing trend.

[0036] This grouping structure, in conjunction with the width gradient, actively guides the deformation of the tabs 340. Specifically, during the core-joining process, the outermost tab group 371 (i.e., the shortest tab group 371 of the base 341) bends first, and within this outermost tab group 371, the outermost tab 340 completes its bend first. This outermost tab 340, as the key tab 340, provides direct spatial constraint and path guidance for the subsequent bending tabs 340 within the same group through physical contact and stress transfer, making the deformation behavior of the tabs 340 in the entire group more synchronous and orderly. Since the length of the base 341 between adjacent tab groups 371 increases in a stepwise manner, the outermost tab 340 in each tab group 371, as the key tab 340, becomes a mechanical reference point, effectively constraining the random deformation tendency of the tabs 340 in the same group, fundamentally avoiding the risk of random interference or inverted insertion of the tabs 330 at the bending points of adjacent tabs 340.

[0037] Furthermore, this grouping design discretizes the length gradient of the base part 341 of the tab 340, making the length of the base part 341 between adjacent tab groups 371 increase in a stepwise manner. This not only ensures the overall bending coordination but also significantly improves manufacturing feasibility and economy. That is, the tabs 340 within the same tab group 371 have uniform dimensions and can be batch-processed using the same set of stamping dies or laser cutting parameters, avoiding the need to adjust process parameters for each piece and greatly reducing equipment debugging time and production costs. The discretized length gradient also facilitates quality inspection and process control. Only a sample of representative tabs 340 within the group is needed to confirm the processing accuracy of the entire group, effectively improving production efficiency.

[0038] In some embodiments, such as Figure 7 As shown, the tab 340 includes a first side 343 and a second side 344 disposed opposite to each other in a first direction X. The first side 343 is disposed away from the first center plane L. The first side 343 is coated with a first coating 350, and the second side 344 is coated with a second coating 360. In the third direction Z, the length of the first coating 350 is greater than the length of the second coating 360.

[0039] When the tab 340 is a positive electrode tab 340, the first coating 350 and the second coating 360 can be positive electrode active material materials (such as lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide) or ceramics, etc.; when the tab 340 is a negative electrode tab 340, the materials of the first coating 350 and the second coating 360 that can be positive electrode 330 can be negative electrode active material materials (such as carbon or silicon) or ceramics, etc.

[0040] It should be noted that both the first coating 350 and the second coating 360 are applied to the root region of the tab 340 near the electrode 330 to enhance the structural strength of the root of the tab 340, that is, to enhance the tear resistance of the root of the tab 340 and prevent root breakage caused by large-angle bending during core rotation.

[0041] Furthermore, in the third direction Z, the length of the first coating 350 is greater than the length of the base portion 341, and the length of the second coating 360 is less than the length of the base portion 341. That is, the extension length of the first coating 350 exceeds the base portion 341, while the extension length of the second coating 360 is shorter than the base portion 341. This asymmetric coating structure forms a complementary protection mechanism mechanically. Specifically, the first coating 350 covers above the root of the extension portion 342 of the tab 340, strengthening the structural strength of the root of the extension portion 342 and significantly enhancing its tear resistance, thus preventing breakage of the root of the extension portion 342 due to large-angle bending during core rotation. The shorter second coating 360 allows the inner side of the tab 340 to maintain lower stiffness in the area near the base portion 341, facilitating inward bending and precisely controlling the bending start position in the root region of the extension portion 342. In this embodiment, through the differentiated design of the inner and outer coating lengths, the tab 340 achieves sufficient structural strength to prevent tearing and inversion, while retaining suitable flexibility to achieve directional bending, thereby effectively balancing mechanical reliability and assembly processability.

[0042] In some embodiments, such as Figure 7 As shown, in the same tab group 370, in the direction pointing towards the first center plane L, the length (or height of the first coating 350) of at least some tabs 340 in the third direction Z shows an increasing trend. This length gradient of the first coating 350 is positively correlated with the length gradient of the base portion 341: the closer the tab 340 is to the first center plane L, the longer its base portion 341 is in the third direction Z, and the higher the bending initiation position. Correspondingly, the height of the first coating 350 increases accordingly to fully cover and protect this high bending point; conversely, the farther away the tab 340 is from the first center plane L, the shorter its base portion 341 is, and the height of the first coating 350 decreases accordingly, forming a precisely matched protection range. This differentiated height design of the first coating 350 on the inner and outer sides ensures that the key weak areas at the connection between the base portion 341 and the extension portion 342 of each tab 340 can obtain better structural reinforcement, avoiding bending and tearing.

[0043] Furthermore, such as Figure 8As shown, the first coating 350 of the tabs 340 located in the same tab group 371 has the same length in the third direction Z. Within the same tab group 370, in the direction pointing towards the first center plane L, the length of the first coating 350 of the multiple tab groups 371 in the third direction Z shows an increasing trend. This grouping strategy discretizes the continuous height gradient, which not only retains the function of co-protecting the length gradient of the base part 341, but also significantly improves manufacturing feasibility. That is, batch operations can be carried out using uniform coating parameters within the same group, and height increments can be achieved by only adjusting the offset of the coating equipment between different groups, avoiding the tedious process of adjusting one piece at a time, and greatly reducing process complexity and manufacturing costs.

[0044] The dual gradient synergy between the height of the first coating 350 and the length of the base 341 achieves a spatially optimized configuration for the mechanical protection of the tabs 340. The inner tab group 371 has a smaller bending angle and a longer base 341, and its higher first coating layer provides a wider range of tear resistance protection; the outer tab group 371 bends more sharply and has a shorter base 341, and its lower first coating layer, while preventing root tearing, facilitates the orderly bending of the tabs 340 in the outer tab group 371 at the connection between the lower base 341 and the extension 342.

[0045] In some embodiments, such as Figure 7 As shown, in the same tab assembly 370, in the direction pointing towards the first center plane L, at least a portion of the second coating 360 of the tabs 340 exhibits an increasing trend in length (or height of the second coating 360) in the third direction Z. This second coating 360 is located inside the tab 340 (close to the first center plane L), and its height gradient works synergistically with but is functionally complementary to the first coating 350: the first coating 350 focuses on tear protection, while the second coating 360 mainly regulates bending curvature and provides inner support. The closer the tab 340 is to the first center plane L, the higher its second coating 360, forming a progressive support structure on the inner side of the bend, preventing plastic damage caused by excessive curvature; the tab 340 farther from the first center plane L has a lower second coating 360 height, reducing resistance to large bends and ensuring smooth bending. This synchronous increasing height design of the inner and outer coatings creates an asymmetrical stiffness distribution at the connection of the base 341, further precisely guiding the tabs 340 to bend orderly towards the first center plane L.

[0046] Furthermore, such as Figure 8As shown, the second coating 360 of the tabs 340 located in the same tab group 371 has the same length in the third direction Z. Within the same tab group 370, in the direction pointing towards the first center plane L, the length of the second coating 360 of multiple tab groups 371 in the third direction Z shows an increasing trend. This grouping strategy is completely consistent with the first coating 350, allowing the tabs 340 in the same group to be processed synchronously during the inner and outer coating processes. Different groups only need to synchronously adjust the offset of the coating equipment to achieve the same gradient change of the second coating 360, significantly reducing process complexity and equipment modification costs.

[0047] In some embodiments, within the same tab assembly 370, at least some of the base portions 341 of the tabs 340 exhibit a decreasing width trend in the second direction Y, meaning that the base portion 341 of the tabs 340 closer to the first center plane L is narrower. This design is closely related to the width gradient structure of the base portion 341-extension portion 342: since the extension portion 342 is narrower than the base portion 341, a stepped structure with sharp angles naturally forms at the connection between the two. During core rotation, the outer tab 340 needs to bend at a larger angle, and its shorter base portion 341 results in a lower step position. This sharp angle of the step is highly likely to mechanically interfere with the edge of the base portion 341 of the adjacent inner tab 340 during bending, posing a risk of piercing the edge of the adjacent tab 340. To avoid this risk, the width of the base portion 341 of the inner tab 340 is progressively reduced to provide clearance for the sharp angle of the step of its adjacent outer tab 340.

[0048] In this embodiment, the base portion 341 of the tab 340 is narrower the closer it is to the first center plane L. This design makes the sides of each tab 340 form a stepped contraction arrangement in the second direction Y, ensuring that when the outer tab 340 is bent, its sharp corner step is always within the avoidance area of ​​the inner tab 340. While eliminating structural physical interference, it maintains the compactness and overall current carrying capacity of the tab group 370, and further improves the safety redundancy and manufacturing consistency of the battery.

[0049] In some embodiments, such as Figure 6a , Figure 6b As shown, the battery cell assembly 300 includes two battery cells 310, each of the battery cells 310 including two electrodes 330 with opposite polarities and a separator 320 disposed between the two electrodes 330; On the third direction Z, the length between the edge of the electrode 330 near the tab 340 and the edge of the separator 320 near the tab 340 is a; in a tab group 370, the length of the base portion 341 of the tab 340 near the first center plane L is y1, and the length of the base portion 341 of the tab 340 away from the first center plane L is y2, a<y1≤1.5a, 0.5a<y2≤a.

[0050] Among them, the shortest length y2 of the base part 341 of the outer tab 340 is in the range of 0.5a < y2 ≤ a, that is, the outer tab 340 has the largest bending angle during the core rotation. The bending start position needs to be lowered as much as possible to avoid excessive stretching and tearing. y2 ≤ a ensures that the base part 341 is not too long and the bending point moves upward, preventing the bending point from being too high and causing mechanical interference with adjacent tabs 340 or the shell 100. At the same time, y2 > 0.5a ensures that the root of the tab 340 has sufficient mechanical strength and current carrying capacity, avoiding breakage due to insufficient cross-section or excessive resistance leading to local overheating under severe bending.

[0051] Among them, the longest length y1 of the base part 341 of the inner electrode 340 is in the range of a < y1 ≤ 1.5a. That is, the bending angle of the inner electrode 340 is smaller, and a longer base part 341 is needed to raise its bending point so that it is staggered with the bending point of the outer electrode 340 in a step-like manner along the third direction Z. y1 > a ensures that the bending position of the inner electrode 340 is significantly higher than that of the outer electrode, achieving spatial separation; while y1 ≤ 1.5a limits the longest dimension, which avoids excessive extension that would cause material waste, increased internal resistance and occupy too much internal space of the housing 100, and also prevents the bending point from being too high and causing assembly conflicts with the pole post 210 or the adapter piece.

[0052] Furthermore, by relating the values ​​of y1 and y2 to the extension amount 'a' of the separator 320 relative to the electrode 330, this range achieves a quantitative match between the length gradient of the tab 340 and the safe distance of the separator 320. All bending points of the tabs 340 are constrained to a minimum distance of 0.5a between the edge of the separator 320 and the edge of the electrode 330. This ensures both the orderly deformation of the tabs 340 and prevents the separator 320 from being squeezed and torn due to excessive bending of the tabs 340, thus guaranteeing the structural safety of the cell 310.

[0053] In some embodiments, such as Figure 6a , Figure 6b As shown, the length of the first coating 350 in the third direction Z is c, and the length of the second coating 360 in the third direction Z is b; where 0.1a≤b<a, a≤c≤2a.

[0054] The first coating 350 on the outer side of the tab 340 (the side away from the first center plane L) plays a core role in tear resistance, and its length c is in the range of a≤c≤2a. c≥a ensures that the coating covers at least to the edge of the separator 320, providing full protection for the low bending point of the outer tab 340 (the area y2≤a) and preventing it from breaking due to excessive stretching. c≤2a limits the maximum extension range of the coating, avoiding material waste caused by excessive coating length, increasing the stiffness of the tab 340 and hindering bending, and preventing the coating from extending to the welding area of ​​the adapter piece and affecting the welding quality.

[0055] The second coating 360 on the inner side of the tab 340 (the side closest to the first center surface L) primarily functions to provide bending support and prevent over-bending damage. Its length b is within the range of 0.1a ≤ b < a. b < a ensures that the farthest end of the coating does not exceed the edge of the separator 320, while c ≥ a ensures that the height of the first coating 350 is greater than that of the second coating 360, making it easier for the tab 340 to bend towards the side closer to the first center surface L. Simultaneously, b ≥ 0.1a ensures that the inner coating fully covers the root area of ​​the base 341, providing sufficient compressive support when the tab 340 bends inward, preventing plastic cracking or metal fatigue due to insufficient curvature at that location.

[0056] 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 (including the claims) is limited to these examples; within the framework 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 the different aspects of this application as described above, which are not provided in the details for the sake of brevity.

[0057] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery, characterized in that, include: The shell and cover plate form an enclosure space, and the cover plate is connected to the pole post; Two battery cell assemblies are arranged in the receiving space along a first direction. Each battery cell assembly includes an electrode sheet. The electrode sheet extends in the direction toward the cover plate and has a tab. The tabs in the same battery cell assembly move toward the first center surface to form a tab group. The tab group is electrically connected to the terminal post. The electrode tab includes a base portion and an extension portion connected to each other. The base portion is connected to the electrode plate. The width of the extension portion in the second direction is smaller than the width of the base portion in the second direction. In the same electrode tab group, in the direction pointing to the first center plane, at least some of the base portions of the electrode tabs show an increasing trend in length in the third direction. The second direction is perpendicular to the first direction, and the third direction is the extension direction of the tab; the first center surface is the contact surface of the two cell assemblies.

2. The battery according to claim 1, characterized in that, The electrode group includes multiple electrode subgroups, each electrode subgroup including at least one electrode. The base of the electrodes within the same electrode subgroup has the same height. Within the same electrode group, the length of the base of the multiple electrode subgroups in the third direction increases in the direction pointing towards the first center plane.

3. The battery according to claim 2, characterized in that, The electrode includes a first side and a second side disposed opposite to each other in a first direction. The first side is disposed away from the first center surface. The first side is coated with a first coating, and the second side is coated with a second coating. In the third direction, the length of the first coating is greater than the length of the second coating.

4. The battery according to claim 3, characterized in that, In the same tab group, in the direction pointing to the first center surface, the length of the first coating of at least some tabs in the third direction shows an increasing trend.

5. The battery according to claim 3, characterized in that, The first coating of the electrodes located in the same electrode group has the same length in the third direction. In the same electrode group, the length of the first coating of the plurality of electrode groups in the third direction in the direction pointing to the first center surface shows an increasing trend.

6. The battery according to claim 3, characterized in that, In the same electrode group, in the direction pointing to the first center surface, the length of the second coating of at least some electrodes shows an increasing trend in the third direction.

7. The battery according to claim 3, characterized in that, The second coating of the electrodes located in the same electrode group has the same length in the third direction. In the same electrode group, the length of the second coating of multiple electrode groups in the third direction increases in the direction pointing to the first center plane.

8. The battery according to claim 1, characterized in that, In the same electrode group, in the direction pointing to the first center plane, the width of the base portion of at least some electrodes decreases in the second direction.

9. The battery according to claim 3, characterized in that, The battery cell assembly includes two battery cells, each of which includes two electrodes with opposite polarities and a separator disposed between the two electrodes; In the third direction, the length between the edge of the electrode sheet near the tab and the edge of the separator near the tab is a; in a group of tabs, the length of the base portion of the tab near the first center surface is y1, the length of the base portion of the tab away from the first center surface is y2, a < y1 ≤ 1.5a, 0.5a < y2 ≤ a.

10. The battery according to claim 9, characterized in that, The length of the first coating is c, and the length of the second coating is b; where 0.1a≤b<a, a≤c≤2a.

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