Battery cell and electric device

Abstract

The invention relates to a battery cell and an electric device. In a battery cell, an electrode assembly has a first end surface and a second end surface opposite to each other in a first direction. The electrode assembly comprises a tab arranged on the first end face. The first direction is the axial direction of the electrode assembly. The insulating viscous layer surrounds the electrode assembly and comprises a first part and a second part which are connected with each other. The first part is at least partially adhered to the first end surface and covers the edge of the tab; and the second part is at least partially adhered to the peripheral side wall of the electrode assembly. The second part is provided with an opening which is communicated with the lower edge, close to the second end face, of the second part and is spaced from the upper edge, connected with the first part, of the second part. By means of the design, space is reserved for expansion of the electrode assembly, the binding effect on the electrode assembly is reduced, all areas of the electrode assembly can be evenly expanded, stress is balanced, and therefore the potential short circuit safety risk caused by pole piece breakage due to stress unbalance is reduced.

Description

Technical Field

[0001] This invention relates to the field of new energy technology, and in particular to a battery cell and an electrical device. Background Technology

[0002] Against the backdrop of the booming development of my country's new energy industry, battery cells with high energy density and high safety characteristics are attracting increasing attention, and new technologies such as solid-state batteries and lithium metal batteries are emerging one after another. Among them, cylindrical steel-cased battery cells with an energy density of over 300Wh / kg and no thermal diffusion characteristics when battery cells are assembled into groups have become one of the important development directions.

[0003] Currently, commercially available high-energy-density cylindrical battery cells generally employ a negative electrode system that combines silicon-based materials with graphite. However, silicon-based materials exhibit a significant volume expansion effect during charge-discharge cycles. Although using a steel shell structure with high mechanical strength can suppress cell expansion and improve the safety of the battery cell to some extent, this constraint actually keeps the cell in a state of incomplete expansion, and its degree of expansion is directly limited by the effective inner diameter of the steel shell.

[0004] Typically, for cylindrical battery cells with tabs on both sides, the casing carries a negative charge. To prevent short circuits caused by contact between the positive tab edge and the casing, the industry commonly uses a low-cost and simple-to-process insulating adhesive layer to cover the edge of the positive tab. However, this type of battery cell poses a short-circuit safety risk. Summary of the Invention

[0005] Therefore, it is necessary to provide a battery cell and electrical device that can reduce the short-circuit risk of battery cells, in order to address the problem of short-circuit risk in battery cells.

[0006] On one hand, this application provides a single battery cell, comprising: An electrode assembly has a first end face and a second end face opposite each other along a first direction. The electrode assembly includes a tab disposed on the first end face. The first direction is the axial direction of the electrode assembly.

[0007] An insulating adhesive layer surrounds the electrode assembly, the insulating adhesive layer comprising a first portion and a second portion connected to each other. The first portion is at least partially adhered to the first end face and covers the edge of the tab. The second portion is at least partially adhered to the peripheral sidewall of the electrode assembly. The second portion has an opening communicating with a lower edge of the second portion near the second end face and spaced relative to an upper edge of the second portion connected to the first portion.

[0008] According to an embodiment of this application, the height H1 of the second portion is the distance between the lower edge and the upper edge along the first direction, and the spacing L1 of the openings is the distance between the end of the opening closest to the upper edge and the upper edge along the first direction, wherein: L1 = (50%~95%)H1, preferably, L1 = (70%~90%)H1.

[0009] And / or, H1 = 10~20mm.

[0010] And / or, the extension length L2 of the opening along the first direction is 5~18mm.

[0011] According to an embodiment of this application, the number N of the openings is multiple, and the multiple openings are evenly or unevenly spaced along the circumference of the electrode assembly, where 2 ≤ the number N of the openings ≤ 8.

[0012] According to an embodiment of this application, the electrode assembly includes a negative electrode sheet, and the negative electrode sheet includes a negative electrode active material.

[0013] If 10% ≤ mass fraction a of silicon-based material in the negative electrode active material ≤ 20%, then 2 ≤ N ≤ 4.

[0014] If 20% < the mass fraction of silicon-based material in the negative electrode active material, a ≤ 30%. 5 ≤ N ≤ 8.

[0015] According to an embodiment of this application, the distance L3 between any two adjacent openings in the direction of their lower edge extension is 5~20mm. And / or, The distance L3 between any two adjacent openings in the direction of extension of the lower edge is (1 / 2 to 1 / 8) of the radial cross-sectional perimeter L4 of the electrode assembly.

[0016] According to an embodiment of this application, the opening includes a cut and / or a notch, wherein the insulating adhesive layer located on both sides of the cut can be pieced together to form a complete insulating adhesive layer, and the notch is formed by the missing portion of the insulating adhesive layer.

[0017] According to an embodiment of this application, the opening is a notch, and the second portion includes a plurality of sequentially connected edges surrounding the opening, any one of the edges being a straight line or a curve.

[0018] According to an embodiment of this application, at least some of the two adjacent edges have a smooth transition.

[0019] According to an embodiment of this application, the shape of the opening is straight, broken, or curved.

[0020] According to an embodiment of this application, the opening width W1 is the same at all points of the opening in the first direction.

[0021] And / or, the opening width W1 = 0.5~6mm, preferably W1 = 2~5mm, or, W1 = πd / N (5%~15%), where d is the diameter of the electrode assembly and N is the number of openings; preferably W1 = πd / N (5%~10%).

[0022] And / or, in the direction from the first end face to the second end face, the opening width gradually increases at each point of the opening, with a maximum opening width W2 = 0.5~6mm, preferably W2 = 2~5mm. Alternatively, W2 = πd / N (5%~15%), where d is the diameter of the electrode assembly and N is the number of openings; preferably W2 = πd / N (5%~10%).

[0023] In another aspect, this application provides an electrical device including the aforementioned battery cell.

[0024] Compared with the prior art, this application has the following beneficial effects: The insulating adhesive layer comprises a first portion and a second portion along its width. The first portion covers the edge of the tab, ensuring that the insulating adhesive layer retains its insulating function for the tab. The second portion has an opening extending through the lower edge. This design both allows space for the expansion of the electrode assembly and reduces the constraint on the electrode assembly, enabling uniform expansion and balanced stress across all areas of the electrode assembly. This reduces the potential short-circuit safety risk caused by electrode breakage due to stress imbalance. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is a cross-sectional structural diagram of a battery cell provided in an embodiment of this application.

[0027] Figure 2 This is a schematic diagram showing the positional relationship between the electrode assembly and the insulating adhesive layer provided in an embodiment of this application.

[0028] Figure 3 This is a top view of an insulating adhesive layer provided in an embodiment of this application in its unfolded state.

[0029] Figure 4 A top view of an insulating adhesive layer in its unfolded state, provided for another embodiment of this application.

[0030] Figure 5 This is a schematic diagram of a structure with a single opening in the second part, provided as an embodiment of this application.

[0031] Figure 6 A schematic diagram of a structure with a single opening in the second part, provided for another embodiment of this application.

[0032] Figure 7 This is a schematic diagram of a structure with multiple openings in the second part provided in an embodiment of this application.

[0033] Figure 8 A schematic diagram of a structure having multiple openings in the second part, provided for another embodiment of this application.

[0034] Figure 9 This is a schematic diagram of a second part having multiple openings, provided for yet another embodiment of this application.

[0035] Figure 10 This is a partially enlarged structural diagram of the opening portion provided in an embodiment of this application.

[0036] Figure 11 This is a partially enlarged structural diagram of the opening portion provided for another embodiment of this application.

[0037] Figure 12 This is a partially enlarged structural diagram of the opening portion provided in another embodiment of this application.

[0038] Figure 13 This is a partially enlarged structural diagram of the opening portion provided in another embodiment of this application.

[0039] Explanation of reference numerals in the attached figures: 100. Electrode assembly; 110. Tab; 110a. Positive tab; 110b. Negative tab; 200, Insulating adhesive layer; 210, First part; 220, Second part; 230, Opening; 221, Upper edge; 222, Lower edge; 231, Edge; 300, Casing; 400, Positive terminal post; 500, Cover plate; 600, Insulating gasket; 700, Negative current collector. Detailed Implementation

[0040] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0041] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0044] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0046] The inventors discovered that in conventional technologies, in addition to covering the edge of the positive electrode tab, a portion of the insulating adhesive layer also covers the peripheral walls of the battery cell, constraining the covered area and essentially constricting it during expansion. This results in uneven expansion between the covered and uncovered portions of the cell, particularly causing significant thickness variations in the outermost negative electrode. Severe stress imbalance can even lead to electrode breakage, posing a potential short-circuit safety risk. In other words, the covered portion of the cell forms indentations, making the negative electrode prone to breakage at these indentations, leading to a short circuit.

[0047] Based on this, one embodiment of this application provides a single battery cell, see [link to previous application]. Figure 1 It includes an electrode assembly 100 and an insulating adhesive layer 200.

[0048] The battery cell includes various types, such as cylindrical battery cells, prismatic battery cells, and pouch battery cells, without specific limitations. Taking a cylindrical battery cell as an example, in addition to the electrode assembly 100 and the insulating adhesive layer 200, it also includes a casing 300, terminals, a cover plate 500, an insulating gasket 600, and a negative electrode current collector 700. Generally, a cylindrical battery cell is designed with positively charged terminals and a negatively charged casing 300. Of course, it is also possible to design the cylindrical battery cell with negatively charged terminals and a positively charged casing 300 as needed. This application does not specifically limit this.

[0049] Continue to refer to Figure 1 Taking a cylindrical battery cell with a positively charged terminal and a negatively charged casing 300 as an example, the battery cell will be explained. Correspondingly, the terminal is named the positive terminal 400.

[0050] Among them, the shell 300, such as the steel shell, is a cylindrical hollow structure that serves as an outer encapsulation component to wrap all internal components.

[0051] The electrode assembly 100 is located in the central region of the housing 300 and extends along the axial direction of the housing 300 (i.e., the first direction below). The electrode assembly 100 has a first end face and a second end face opposite to each other along the first direction. The first end face faces the closed end of the housing 300, and the second end face faces the open end of the housing 300.

[0052] The first direction is the axial direction of the electrode assembly 100. The first direction is the direction in which the electrode assembly 100 extends along its central axis after it has been formed. The first direction is the length direction of the cylindrical electrode assembly 100.

[0053] Reference Figure 1 and Figure 2 The cover plate 500 is assembled to the open end of the housing 300 and sealed. The positive electrode post 400 is disposed through the closed end of the housing 300 and is insulated from the housing 300 by an insulating component (not shown in the figure), which is generally a plastic component. The inner end of the positive electrode post 400 is electrically connected to the positive electrode tab 110a on the first end face of the electrode assembly 100, and the outer end is the positive output terminal.

[0054] An insulating gasket 600 is provided between the housing 300 and the first end face of the electrode assembly 100. The insulating gasket 600 surrounds the connection part of the positive electrode tab 110a and the positive electrode post 400, realizing the insulation isolation between the housing 300 and the positive electrode tab 110a of the electrode assembly 100. The negative electrode current collector 700 is located between the second end face of the electrode assembly 100 and the open end of the housing 300. One side is electrically connected to the negative electrode tab 110b of the electrode assembly 100, and the other side is electrically connected to the inner wall of the housing 300, realizing the electrical connection between the negative electrode of the electrode assembly 100 and the housing 300.

[0055] The following section focuses on the electrode assembly 100 and the insulating adhesive layer 200. (Refer to...) Figure 1 The electrode assembly 100 can also be referred to as a battery cell. The electrode assembly 100 is the core component of a single battery cell. The electrode assembly 100 can be formed by winding or stacking positive electrode plates, negative electrode plates, and a separator that serves as an insulator between the negative electrode plates and the positive electrode plates. The tabs 110 of the electrode assembly 100 are divided into positive tabs 110a and negative tabs 110b, which are led out from the positive electrode plate and the negative electrode plate, respectively.

[0056] The electrode assembly 100 includes a tab 110 disposed on the first end face. The tab 110 can be either a positive tab 110a or a negative tab 110b, without specific limitation. When the tab 110 is a positive tab 110a, the corresponding battery cell is a battery cell with a positively charged terminal and a negatively charged casing 300. When the tab 110 is a negative tab 110b, the corresponding battery cell is a battery cell with a negatively charged terminal and a positively charged casing 300.

[0057] An insulating adhesive layer 200 surrounds the electrode assembly 100. (See reference...) Figure 3 and Figure 4 The insulating adhesive layer 200 includes a first portion 210 and a second portion 220 that are connected to each other.

[0058] The insulating adhesive layer 200, in its unfolded state, comprises a first portion 210 and a second portion 220 sequentially distributed along its width. The first portion 210 is at least partially adhered to the first end face and covers the edge of the tab 110. This prevents short circuits between the edge of the tab 110 and the housing 300. The second portion 220 is at least partially adhered to the peripheral sidewall of the electrode assembly 100.

[0059] The second part 220 is bonded to the peripheral sidewall of the electrode assembly 100 to strengthen the overall connection strength between the insulating adhesive layer 200 and the electrode assembly 100, preventing the insulating adhesive layer 200 from falling off completely during the expansion and contraction of the battery cell; at the same time, it further expands the insulation protection range and improves the circumferential insulation reliability of the electrode assembly 100.

[0060] The second part 220 has an opening 230 that connects to the lower edge 222 of the second part 220 near the second end face and is spaced apart from the upper edge 221 of the second part 220 that connects to the first part 210.

[0061] The direct connection between the second part 220 and the first part 210 is the upper edge 221 of the second part 220. The lower edge 222 of the second part 220 is the edge of the second part 220 near the second end face, which is also the edge of the insulating adhesive layer 200 as a whole near the second end face.

[0062] In the first direction, the opening 230 only partially penetrates the second part 220. The opening 230 connects to the lower edge 222, but does not extend to the upper edge 221, and is spaced apart from the upper edge 221.

[0063] On the one hand, the design of opening 230 connecting to the lower edge 222 of the second part 220 reduces the binding effect on the electrode assembly 100, providing a larger buffer space for the volume expansion of the electrode assembly 100 during charge and discharge cycles, reducing the uneven expansion of the area covered and uncovered by the insulating adhesive layer 200 of the electrode assembly 100. In this way, each area of ​​the electrode assembly 100 can expand uniformly and be subjected to balanced forces, thereby reducing the potential short circuit safety risk caused by electrode breakage due to force imbalance.

[0064] On the other hand, the design of the opening 230 and the upper edge 221 being spaced apart preserves the structural integrity of the connection area between the upper edge 221 of the second part 220 and the first part 210, ensuring the overall connection strength of the insulating adhesive layer 200, avoiding structural failure of the insulating adhesive layer 200 due to excessive extension of the opening 230, and taking into account both the buffering effect and the connection stability.

[0065] The direction of the opening 230 is not specifically limited; it can be straight, broken, or curved. (See reference...) Figure 4 and Figure 7 The number of openings of 230 is not limited; it can be one, two, or more.

[0066] The opening 230 includes a cut and / or a notch, wherein the insulating adhesive layer 200 located on both sides of the cut can be pieced together to form a complete insulating adhesive layer 200, and the notch is the missing part of the insulating adhesive layer 200 formed by the insulating adhesive layer 200.

[0067] Compared with the prior art, this application has the following beneficial effects: The insulating adhesive layer 200 includes a first portion 210 and a second portion 220 along its width. The first portion 210 covers the edge of the tab 110, ensuring that the insulating adhesive layer 200 retains its insulating function for the tab 110. The second portion 220 has an opening 230 extending through its lower edge 222. This design provides space for the expansion of the electrode assembly 100 while reducing the constraint on the electrode assembly 100, allowing for uniform expansion and balanced stress distribution across all areas of the electrode assembly 100. This reduces the potential short-circuit safety risk caused by electrode breakage due to stress imbalance.

[0068] In some embodiments, refer to Figure 5 , Figure 6 and Figure 7 The height H1 of the second part 220 is the distance between the lower edge 222 and the upper edge 221 along the first direction, and the spacing L1 of the openings 230 is the distance between the end of the opening 230 near the upper edge 221 and the upper edge 221 along the first direction, wherein: L1 = (50%~95%)H1. When the gap L1 of the opening 230 is within the range of (50%~95%)H1, it can better maintain the structural integrity of the connection area between the upper edge 221 of the second part 220 and the first part 210 while ensuring sufficient space is reserved for the expansion of the electrode assembly 100, thus ensuring the overall connection strength of the insulating adhesive layer 200.

[0069] In some specific embodiments, refer to Figure 5 , Figure 6 and Figure 7L1 = (70%~90%)H1. Based on this, it is possible to further balance the relationship between reserving sufficient space for the expansion of the electrode assembly 100 and ensuring the overall connection strength of the insulating adhesive layer 200.

[0070] In some specific embodiments, H1 = 10~20mm.

[0071] This design ensures that the second part 220 has sufficient axial coverage length, which can achieve reliable bonding with the peripheral sidewall of the electrode assembly 100, ensuring the insulation protection range, and avoid material waste or excessive constraint on cell expansion due to excessive size. It can be adapted to the size of the electrode assembly 100 of conventional cylindrical batteries (such as 18650 and 21700 models), improving the versatility of the solution.

[0072] In some embodiments, the extension length L2 of the opening 230 along the first direction is 5~18mm.

[0073] The opening 230 of this design can better maintain the structural integrity of the connection area between the upper edge 221 of the second part 220 and the first part 210 while ensuring sufficient space for the expansion of the electrode assembly 100, thus ensuring the overall connection strength of the insulating adhesive layer 200.

[0074] In some embodiments, refer to Figure 7 , Figure 8 and Figure 9 The number N of openings 230 is multiple, and the multiple openings 230 are evenly or unevenly spaced along the circumference of the electrode assembly 100, where 2 ≤ the number N of openings 230 ≤ 8.

[0075] Compared to a single opening 230, multiple openings 230 can evenly distribute the circumferential expansion stress of the electrode assembly 100 to each opening 230 location, avoiding localized tearing of the insulating adhesive layer 200 caused by stress concentration at a single opening 230; at the same time, it makes the expansion buffering of each region of the electrode assembly 100 more uniform, improving the structural stability of the battery cell during cycling.

[0076] Limiting the number of openings 230 to between 2 and 8 can both meet the requirement of reserving space for the expansion of the electrode assembly 100 and avoid a significant decrease in the overall structural strength of the insulating adhesive layer 200 due to too many openings 230.

[0077] Reference Figure 7 and Figure 8When multiple openings 230 are evenly spaced along the circumference of the electrode assembly 100, the constraints on the electrode assembly 100 in all directions during expansion are more balanced. This prevents localized stress concentration during expansion, effectively extending the lifespan of the battery cell. Simultaneously, the evenly distributed openings 230 help improve the stability of the insulating adhesive layer 200's wrapping around the peripheral sidewalls of the electrode assembly 100, resulting in more uniform and reliable insulation protection. Furthermore, it reduces the difficulty of forming openings 230 on the insulating adhesive layer 200, simplifying its manufacturing process.

[0078] Reference Figure 9 When multiple openings 230 are unevenly spaced along the circumference of the electrode assembly 100, the design can be tailored to the expansion characteristics of different parts of the electrode assembly 100. For example, in areas where the electrode assembly 100 expands significantly during charging and discharging, appropriately increasing the number of openings 230 or adjusting the spacing between them can provide more expansion space and reduce the impact of expansion on battery performance. Conversely, in areas with relatively small expansion, the number of openings 230 can be reduced to ensure the connection strength and insulation performance of the insulating adhesive layer 200 in these areas. This flexible design approach can better adapt to the expansion requirements of different types of electrode assemblies 100, improving the performance and safety of individual battery cells.

[0079] In some specific embodiments, the electrode assembly 100 includes a negative electrode sheet, which includes a negative electrode active material.

[0080] If 10% ≤ the mass fraction of silicon-based materials in the negative electrode active material ≤ 20%, then 2 ≤ N ≤ 4.

[0081] If 20% < the mass fraction of silicon-based materials in the negative electrode active material is ≤30%, then 5 ≤ N ≤ 8.

[0082] The negative electrode includes a current collector and a layer of negative electrode active material disposed on at least one side of the current collector along its thickness direction. The higher the silicon-based material content in the negative electrode active material, the greater the volume expansion during charge-discharge cycles, and the higher the buffering requirement for the insulating adhesive layer 200. This parameter provides a core basis for the precise matching of the number of openings 230.

[0083] The number N of openings 230 is set according to different ranges of silicon-based material mass fraction.

[0084] Reference Figure 9When the mass fraction of silicon-based material is between 10% and 20%, controlling the number N of openings 230 to between 2 and 4 can ensure the basic structural stability of the negative electrode while reserving some space for moderate expansion of the negative electrode during charging and discharging. Because within this mass fraction range, the expansion effect caused by silicon-based material is relatively mild, an appropriate number of openings 230 can meet the expansion requirements without weakening the overall strength of the negative electrode and the connection function of the insulating adhesive layer 200 due to excessive openings 230.

[0085] Reference Figure 7 and Figure 8 When the mass fraction of silicon-based material increases to 20%-30%, adjusting the number N of openings 230 to between 5 and 8 can better address the more pronounced expansion caused by the increased silicon content. More openings 230 provide more expansion space, effectively reducing internal stress caused by expansion and preventing structural damage or performance degradation of the negative electrode. Simultaneously, a reasonable number of openings 230 will not excessively affect the insulation performance of the insulating adhesive layer 200 or the stability of the encapsulation of the electrode assembly 100, ensuring that the battery cell can operate stably and efficiently under different silicon-based material mass fractions.

[0086] In some embodiments, refer to Figure 7 The distance L3 between any two adjacent openings 230 in the direction of extension of the lower edge 222 is 5~20mm.

[0087] This design ensures that there is sufficient solid width between adjacent openings 230, avoiding excessive fragmentation of the circumferential structure of the insulating adhesive layer 200 due to insufficient spacing, thus ensuring the bonding strength and structural integrity of the layer with the circumferential sidewall of the electrode assembly 100; at the same time, it avoids uneven distribution of the buffer area due to excessive spacing, which would affect the uniformity of circumferential expansion.

[0088] In some embodiments, refer to Figure 7 The distance L3 between any two adjacent openings 230 in the direction of extension of the lower edge 222 is (1 / 2 to 1 / 8) of the radial cross-sectional perimeter L4 of the electrode assembly 100.

[0089] This proportional limitation allows the spacing L3 to adapt to electrode assemblies 100 with different cross-sectional perimeter specifications, thereby improving the versatility of the solution and ensuring that the spacing between adjacent openings 230 can be kept within a reasonable range regardless of the diameter of the electrode assembly 100 (e.g., 18650 model d=18mm, 21700 model d=21mm), ensuring a balance between buffer uniformity and structural strength, and avoiding design failures caused by differences in the size of the electrode assembly 100.

[0090] In some embodiments, the opening 230 includes a cut and / or a notch, wherein the portions of the insulating adhesive layer 200 located on both sides of the cut can be pieced together to form a complete insulating adhesive layer 200, and the notch is formed by the missing portion of the insulating adhesive layer 200.

[0091] Reference Figure 5 The cut is a linear slit structure formed on the second part 220 of the insulating adhesive layer 200 by a cutting process. After cutting, the material of the insulating adhesive layer 200 is not lost, and the two sides can be reassembled into a complete structure.

[0092] The cutting process is simple and can be directly formed by die-cutting or cutting machine, making it suitable for mass production; the linear structure of the cutting can flexibly adjust the length and position to adapt to different buffering needs; the feature that the two sides can be spliced ​​together makes the insulating adhesive layer 200 a complete roll when not assembled, which is convenient for storage, transportation and assembly operations around the electrode assembly 100.

[0093] Reference Figure 6 The gap is a hollow structure formed by removing part of the insulating adhesive layer 200 material through cutting or punching processes. The insulating adhesive layer 200 material is missing and cannot be restored to its complete state by splicing the two sides together. The hollow area is larger, which can provide stronger buffering capacity and adapt to battery cells with larger expansion. It can be flexibly designed into various shapes such as rectangle and trapezoid to adapt to different structural spaces and stress dispersion requirements.

[0094] On the one hand, the end of the notch (the end of the notch away from the lower edge 222 of the second part 220) can release stress and prevent the insulating adhesive layer 200 from tearing from the end of the opening 230 when the electrode assembly 100 expands, thus affecting the insulation performance of the tape; on the other hand, the notch can prevent the insulating adhesive layer 200 from folding from the opening 230, which would cause uneven gaps between the housing 300 and the electrode assembly 100.

[0095] The opening 230 can be in the form of a cut, a notch, or both. This approach improves the process adaptability and structural flexibility of the solution, allowing for the selection of a suitable opening 230 form based on the specific specifications of the battery cell (such as cell expansion and electrode assembly diameter 100) and production equipment conditions (such as the availability of punching equipment), thereby reducing production difficulty and cost.

[0096] In some embodiments, the opening 230 is straight, polygonal, or curved. Regardless of whether the opening 230 is a cut or a notch, it can be straight, polygonal, or curved.

[0097] Different shaped openings 230 play different roles in the battery cell. (Refer to...) Figure 5 and Figure 6The straight opening 230 is relatively simple to process, which can improve efficiency in mass production. In addition, its structure is regular and has a certain regularity in stress distribution, making it suitable for battery cells with high requirements for structural stability.

[0098] The zigzag opening 230 can increase the length of the opening 230 within a limited space, thereby enhancing the buffering effect, and is especially suitable for batteries with large cell expansion and relatively compact space.

[0099] The curved opening 230 has a more flexible stress dispersion capability, which can better adapt to the complex stress distribution inside the battery. Without affecting the overall strength of the insulating adhesive layer 200, it can better relieve the constraint on the electrode assembly 100 and reduce the uneven expansion of the electrode assembly 100 in the areas covered and uncovered by the insulating adhesive layer 200.

[0100] Reference Figure 10 , Figure 11 , Figure 12 and Figure 13 In some embodiments, the opening 230 is a notch, and the second portion 220 includes a plurality of sequentially connected edges 231 surrounding the opening 230, any one edge 231 being a straight line or a curve.

[0101] Multiple edges 231 are distributed around the notch, and each edge 231 can be independently set as a straight line or a curve. For example, the side edge 231 can be either a straight line or a curve; see reference. Figure 10 , Figure 11 , Figure 12 One specific example is where the edges 231 of both sides are straight lines. (See reference...) Figure 13 One specific example is that the edges 231 on both sides are curved.

[0102] Referring to the aforementioned description of the shape of the opening 230, the design of the straight edge 231 makes the manufacturing process simpler and more efficient.

[0103] Similarly, the bottom edge 231 can also be set to a straight line or a curve. (See reference...) Figure 11 , Figure 12 and Figure 13 One specific example is where the bottom edge 231 is a straight line. (See reference...) Figure 10 The bottom edge 231 is curved, which is one specific case.

[0104] Referring to the aforementioned description of the shape of opening 230, the design of the curved edge 231 gives opening 230 greater adaptability and cushioning capability.

[0105] Reference Figure 11 and Figure 13 In some embodiments, at least two adjacent edges 231 are smoothly transitioned.

[0106] In this embodiment, the connection between two adjacent edges 231 (whether straight or curved) is rounded, rather than sharp right angles or angular transitions. Sharp edge 231 connections are high-risk areas for stress concentration. Under the cyclic load of repeated expansion and contraction of the electrode assembly 100, cracks may form and propagate, eventually leading to tearing failure of the insulating adhesive layer 200. A smooth transition can completely eliminate stress concentration at the connection, significantly improving the fatigue resistance and service life of the insulating adhesive layer 200, and ensuring the structural stability of the battery cell during long-term cycling.

[0107] Reference Figure 10 and Figure 11 In some embodiments, the width W1 of the opening 230 is the same at all locations of the opening 230 in the first direction.

[0108] In this embodiment, the circumferential width of the opening 230 is equal at all points in the first direction (axial direction). This structure is simple in design, easy to manufacture, and facilitates precise dimensional control, making it suitable for mass production. The equal-width opening 230 ensures uniform buffering capacity at all axial positions, making it suitable for scenarios where the axial expansion of the battery cell is uniform.

[0109] In some specific embodiments, the width of the opening 230, W1, is 0.5~6mm, preferably W1=2~5mm.

[0110] In this embodiment, limiting the width of the opening 230 to a reasonable range achieves a balance between buffering effect and structural strength. This avoids insufficient buffering space due to an excessively small width (<0.5mm), which would fail to meet the cell expansion requirements; and avoids an excessively large width (>6mm), which would result in an overly narrow circumferential solid portion of the insulating adhesive layer 200, reducing bonding strength and structural integrity. Otherwise, when the electrode assembly 100 expands and is compressed, the first part 210 could easily be pulled, causing it to detach from the tab 110 and short-circuit between the tab 110 and the housing 300. The preferred range further optimizes the balance between buffering effect and structural strength, adapting to the expansion requirements of most conventional silicon-based negative electrode cells.

[0111] In some other specific embodiments, W1 = πd / N (5%~15%), where N is the number of openings 230 and d is the diameter of the electrode assembly 100.

[0112] The battery cell corresponding to the electrode assembly 100 is a cylindrical battery cell. πd is the radial cross-sectional perimeter of the electrode assembly 100, and πd / N is the reference value for the circumferential spacing between adjacent openings 230. This design ensures a precise match between the width of the opening 230 and the size and number of openings 230 of the electrode assembly 100, avoiding the problem of mismatch between the width of the opening 230 and the buffering requirements due to changes in the diameter of the electrode assembly 100 or the number of openings 230; it also improves the versatility of the solution, ensuring that battery cells of different specifications can obtain optimal buffering effect and structural stability. Preferably, W1 = πd / N (5%~10%).

[0113] Reference Figure 12 and Figure 13 In other embodiments, the width of the opening 230 gradually increases in the direction from the first end face to the second end face.

[0114] In this embodiment, the opening 230 has a gradually increasing width. Typically, the expansion of the silicon-based negative electrode cell is greater near the second end face (away from the tab 110). The gradually increasing width design allows the area with greater expansion to have more buffer space, further improving buffer adaptability. At the same time, it can reduce the width of the upper edge 221 area of ​​the opening 230, ensuring the structural strength of the connection area of ​​the upper edge 221 of the insulating adhesive layer 200.

[0115] In some specific embodiments, the maximum opening 230 width W2 is 0.5~6mm, preferably W2=2~5mm.

[0116] Similarly, the width range of the opening 230 in this embodiment is reasonably set, achieving a balance between buffering effect and structural strength. For specific effects, please refer to the relevant description of the equal-width portion of the opening 230 above, which will not be repeated here.

[0117] In some specific embodiments, W2 = πd / N (5%~15%), where d is the diameter of the electrode assembly 100, and preferably W2 = πd / N (5%~10%).

[0118] Similarly, the width range of the opening 230 in this embodiment is reasonably set, achieving a precise match between the width of the opening 230 and the size of the electrode assembly 100 and the number of openings 230. For specific effects, please refer to the relevant description of the equal width portion of the opening 230 mentioned above, which will not be repeated here.

[0119] This application also provides an electrical device, which includes the aforementioned battery cell and is capable of providing electrical energy from the aforementioned battery cell. The electrical device can be a vehicle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, power tool, energy storage device, amusement equipment, elevator, and lifting equipment, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, or electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.; energy storage devices can be energy storage walls, base station energy storage, container energy storage, etc.; amusement equipment can be a carousel, a drop tower, etc.

[0120] The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended vehicles, etc. For new energy vehicles, the aforementioned battery can serve as a driving power source, thereby replacing fossil fuels to provide propulsion. This application does not impose any special restrictions on the aforementioned electrical devices.

[0121] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0122] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A battery cell, characterized in that, include: An electrode assembly (100) has a first end face and a second end face opposite each other along a first direction; the electrode assembly (100) includes a tab (110) disposed on the first end face; the first direction is the axial direction of the electrode assembly (100); An insulating adhesive layer (200) surrounds the electrode assembly (100), the insulating adhesive layer (200) comprising a first portion (210) and a second portion (220) connected to each other; the first portion (210) is at least partially adhered to the first end face and covers the edge of the tab (110); the second portion (220) is at least partially adhered to the peripheral sidewall of the electrode assembly (100); the second portion (220) has an opening (230) communicating with the lower edge (222) of the second portion (220) near the second end face and spaced apart from the upper edge (221) of the second portion (220) connected to the first portion (210).

2. The battery cell according to claim 1, characterized in that, The height H1 of the second part (220) is the distance between the lower edge (222) and the upper edge (221) along the first direction, and the spacing L1 of the openings (230) is the distance between the end of the opening (230) near the upper edge (221) along the first direction and the upper edge (221), wherein: L1 = (50%~95%)H1, preferably, L1 = (70%~90%)H1; And / or, H1 = 10~20mm; And / or, the extension length L2 of the opening (230) along the first direction is 5~18mm.

3. The battery cell according to claim 1, characterized in that, The number N of the openings (230) is multiple, and the multiple openings (230) are evenly or unevenly spaced along the circumference of the electrode assembly (100), where 2 ≤ the number N of the openings (230) ≤ 8.

4. The battery cell according to claim 3, characterized in that, The electrode assembly (100) includes a negative electrode sheet, which includes a negative electrode active material; If 10% ≤ mass fraction of silicon-based material in the negative electrode active material a ≤ 20%; 2 ≤ N ≤ 4; If 20% < the mass fraction of silicon-based material in the negative electrode active material, a ≤ 30%; 5 ≤ N ≤ 8.

5. The battery cell according to claim 1, characterized in that, The distance L3 between any two adjacent openings (230) in the direction of extension of the lower edge (222) is 5~20mm; and / or, The distance L3 between any two adjacent openings (230) in the direction of extension of the lower edge (222) is (1 / 2 to 1 / 8) of the radial cross-sectional perimeter L4 of the electrode assembly (100).

6. The battery cell according to claim 1, characterized in that, The opening (230) includes a cut and / or a notch, wherein the insulating adhesive layer (200) located on both sides of the cut can be pieced together to form a complete insulating adhesive layer (200), and the notch is formed by the missing portion of the insulating adhesive layer (200).

7. The battery cell according to claim 6, characterized in that, The opening (230) is a notch, and the second part (220) includes a plurality of sequentially connected edges (231) surrounding the opening (230), any of which is a straight line or a curve.

8. The battery cell according to claim 7, characterized in that, At least some of the two adjacent edges (231) have a smooth transition.

9. The battery cell according to claim 7, characterized in that, In the first direction, the width W1 of the opening (230) is the same at all locations of the opening (230); And / or, the width of the opening (230) is W1 = 0.5~6mm, preferably W1 = 2~5mm, or, W1 = πd / N (5%~15%), where d is the diameter of the electrode assembly (100) and N is the number of openings; preferably W1 = πd / N (5%~10%). And / or, in the direction from the first end face to the second end face, the width of the opening (230) at each point gradually increases, with the maximum opening (230) width W2 = 0.5~6mm, preferably W2 = 2~5mm; or, W2 = πd / N (5%~15%), where d is the diameter of the electrode assembly (100) and N is the number of openings; preferably W2 = πd / N (5%~10%).

10. An electrical appliance, characterized in that, Includes the battery cells as described in claims 1 to 9.

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