Battery cells and batteries

Abstract

The application discloses an electric core and a battery. The electric core comprises a bare electric core and a tab structure. The bare electric core comprises a plurality of pole pieces arranged in a stack. The tab structure comprises a plurality of tab pieces arranged in a stack. Each tab piece comprises a first end and a second end arranged oppositely. The first end is close to and connected to a corresponding pole piece. The distance between the second end of each tab piece and the first end decreases and then increases from one side of the tab structure to the other side. The tab structure has a gradient tab feature. Therefore, the size of the tab structure after welding is appropriate, and the tab structure can be directly welded with a connecting piece or a cover plate. The tab does not need to be cut, so that the generation of tab debris is avoided.

Description

Technical Field

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

[0002] As lithium-ion batteries pursue higher energy density and larger capacity, the number and thickness of battery cell layers are constantly increasing, leading to a corresponding increase in the number of tab layers. After the design of the connecting tabs and cover plates reaches its limits, the tabs need to be cut after ultrasonic welding before laser welding to the connecting tabs and cover plates. However, due to the excessive number of tab layers, the cutting effect is poor, easily leading to stringing or debris on the tabs, affecting the electrochemical and safety performance of the battery. Utility Model Content

[0003] This application provides a method for preparing a battery cell, a battery, and a battery, which does not generate electrode debris, thereby at least partially solving the above-mentioned technical problems.

[0004] To achieve the above objectives, according to a first aspect of this application, a battery cell is provided, comprising:

[0005] A bare battery cell, comprising multiple stacked electrode sheets;

[0006] The electrode structure includes multiple stacked electrode pieces, each electrode piece having a first end and a second end disposed opposite to each other. The first end is close to and connected to the corresponding electrode piece, pointing from one side of the electrode structure to the other side. The distance between the second end and the first end of the multiple electrode pieces decreases and then increases.

[0007] Optionally, pointing from one side of the tab structure to the other, at least one tab on one side of the tab structure is a first tab, and at least one tab on the other side of the tab structure is a second tab. The distance between the second end and the first end of the first tab is greater than the distance between the second end and the first end of the second tab. At a certain convergence height, when the tab structure converges, the tabs on both sides of the tab structure can be welded together, ensuring the feasibility and effectiveness of the welding operation.

[0008] Optionally, at least one of the tabs with the shortest distance between the second end and the first end is a third tab, wherein the number of tabs between the first tab and the third tab is greater than or equal to the number of tabs between the second tab and the third tab. By adjusting the distribution of the number of tabs between the first tab, the second tab, and the third tab, which serves as a convergence reference, the arrangement density of the tabs on both sides is more balanced when the tab structure converges towards the third tab position.

[0009] Optionally, the distance between the second end and the first end of the third electrode tab is H3, where 23 ≤ H3 ≤ 25 mm. The size design of the third electrode tab is reasonable. If it is smaller than the set range value, the height of the electrode tab structure will be too small, which is not conducive to welding and assembly with the adapter plate or cover plate. If the height of the electrode tab structure is too large, the installation space of the electrode tab structure will be insufficient, and the electrode tab needs to be further cut.

[0010] Optionally, the multiple tabs on both sides of the tab structure converge and fit together towards the third tab. Using the third tab as the reference tab, the distance between the other tabs and the reference tab, and the bending amplitude of each tab, are controllable. This reduces the probability of breakage due to excessive bending of some tabs, thus improving the reliability of the tab structure.

[0011] Optionally, the distance between the gathered third electrode tab and the plane containing the bottom of the bare cell is L, where 5mm ≤ L ≤ 7mm. This design of the distance between the gathered third electrode tab and the plane containing the bottom of the bare cell balances the bending radius and dimensional requirements of the first and second electrode tabs, improving the reliability of the cell.

[0012] Optionally, the system also includes an adapter piece, to which the converged and fitted tab structure is welded. Welding the converged and fitted tab structure to the adapter piece, and then welding the adapter piece to the battery cover, is a simple operation.

[0013] Optionally, the distance between the second end and the first end of the first electrode tab is H1, where 38mm≤H1≤40mm. The size design of the first electrode tab is reasonable. If the size design of the first electrode tab is smaller than the set value, the convergence size of the first electrode tab is insufficient. If the size design of the first electrode tab is larger than the set value, the convergence size of the first electrode tab is still large, and further cutting of the electrode tab is required.

[0014] Optionally, the distance between the second end and the first end of the second electrode tab is H2, where 25mm ≤ H2 ≤ 27mm. The size design of the second electrode tab is reasonable. If the size of the second electrode tab is smaller than the set value, the distance between the second electrode tabs will be insufficient, affecting the performance of the electrode tab structure. If the size of the second electrode tab is larger than the set value, the size of the gathered second electrode tabs will still be large, requiring further trimming of the electrode tabs.

[0015] Optionally, each layer of the electrode sheet and the corresponding tab are integrally die-cut. Integral die-cutting of each layer of the electrode sheet and tab facilitates the processing and shaping of the electrode sheet and tab.

[0016] Optionally, the electrode structure can be a positive electrode structure and / or a negative electrode structure. This eliminates the need to cut the positive and / or negative electrode tabs, improving battery electrical performance and safety.

[0017] Optionally, from one side of the electrode structure to the other, the distances between the second end and the first end of the plurality of electrode pieces decrease in a geometric sequence.

[0018] And / or, from one side of the electrode structure to the other, the distances between the second ends and the first ends of the plurality of electrode plates increase in a geometric sequence.

[0019] Multiple tabs increase or decrease proportionally, and their regular dimensions can be matched with standardized mold development and automated processing procedures. There is no need to set cutting parameters for each tab individually, which reduces the adjustment time in the processing process, reduces the complexity of operation, and helps to improve the efficiency of batch processing.

[0020] Optionally, the fixed value of the geometric series decreasing between the second end and the first end of the electrode tab is ΔH, where 0≤ΔH≤1mm;

[0021] And / or, the fixed value of the geometric progression between the second end and the first end of the electrode tab is ΔH, where 0≤ΔH≤1mm.

[0022] The fixed values ​​of the geometric progression decreasing or proportional progression increasing between the second and first ends of the electrode tab are available in multiple options, which can adapt to the spatial layout of different batteries and reduce the cost of customization.

[0023] According to a second aspect of this application, a battery is provided, comprising the cell described in any one of the foregoing claims.

[0024] The battery cell and battery of this application embodiment include a bare cell and a tab structure. From one side of the tab structure to the other, the distance between the second end and the first end of multiple tabs decreases and then increases, giving the tab structure a gradient tab feature. Therefore, the dimensions of the tab structure after welding are more suitable and can be directly welded to connecting pieces or cover plates. No cutting of the tabs is required, thus eliminating the generation of tab debris. This effectively prevents debris and wire breakage from appearing at the tab edges due to poor tab cutting, thereby reducing the probability of tab debris falling into the cell pack and causing short circuits, increased self-discharge rate, and reduced capacity. This significantly improves the cell manufacturing yield, performance, and lifespan.

[0025] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments 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.

[0027] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0028] Figure 1 This is a schematic diagram of the structure of the battery cell provided in an exemplary embodiment of this disclosure;

[0029] Figure 2 This is an internal cross-sectional view of the structural schematic diagram of the battery cell tab structure after the distance provided in the exemplary embodiment of this disclosure;

[0030] Figure 3 This is a schematic diagram of the electrode structure and the adapter piece welded together in an exemplary embodiment of the present disclosure;

[0031] Figure 4 This is a schematic diagram of the first type of electrode tabs in the electrode tab structure of the battery cell provided in the exemplary embodiments of this disclosure, which are first decreasing and then increasing;

[0032] Figure 5 This is a schematic diagram of the first type of electrode tabs in the electrode tab structure of the battery cell provided in the exemplary embodiments of this disclosure, which are first decreasing and then increasing;

[0033] Figure 6 This is a schematic diagram of a first type of electrode tab structure in the battery cell provided in an exemplary embodiment of this disclosure, showing a decreasing-then-increasing arrangement of the tabs.

[0034] Explanation of reference numerals in the attached figures:

[0035] 10. Bare cell; 11. Electrode; 111. First-stage electrode; 112. i-th-stage electrode; 113. N-th-stage electrode; 20. Electrode structure; 21. Electrode; 211. First end; 212. Second end; 22. First electrode; 23. Second electrode; 24. Third electrode; 25. First-stage electrode; 26. i-th-stage electrode; 27. N-th-stage electrode; 30. Adapter piece; Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0037] In related technologies, laminated battery cells include positive and negative electrode units. The positive electrode unit includes a positive electrode sheet and a separator, with a positive electrode tab on one side of the positive electrode sheet. The negative electrode unit includes a negative electrode sheet and a separator, with a negative electrode tab on one side of the negative electrode sheet. Positive and negative electrode units are alternately arranged along the height of the laminated battery cell. The positive and negative electrode sheets in the laminated battery cell are separated by a separator. As the number of cell layers increases, the number of positive and negative electrode sheets also increases. The positive electrode tabs are ultrasonically welded and then cut out of the laminated battery cell. The negative electrode tabs are only removed after all the negative electrode tabs have been welded. Due to the large number of layers of positive and negative electrode tabs, tab stringing or tab debris can easily occur during cutting.

[0038] The presence of copper or aluminum shavings in lithium batteries may cause a series of problems: (1) Internal short circuit: The sharp edges of the tab debris may puncture the separator during battery charging and discharging, leading to an internal short circuit in the battery; (2) Reduced battery safety: During battery charging and discharging, the local current increase at the short circuit point will generate a large amount of heat, which may trigger a chain reaction such as electrolyte decomposition and separator melting, ultimately leading to battery fire or explosion; (3) Reduced battery capacity: If there are tab debris in the battery, it may form a micro short circuit path, continuously consuming electricity, leading to an increase in battery self-discharge rate. Long-term self-discharge will reduce the battery capacity and cycle life; (4) Decreased pack consistency: If there are tab debris inside the battery pack, it will lead to a decrease in the overall pack capacity consistency, a reduction in cycle life and energy life, and an increase in the burden on the battery management system (BMS).

[0039] See Figure 1 and Figure 4To address the problems in electrode processing in related technologies, this application provides a battery cell, including a bare battery cell 10 and an electrode structure 20. The bare battery cell 10 includes multiple stacked electrode sheets 11, which can be either positive or negative electrode sheets. Each layer of electrode sheets 11 has the same dimensions; for example, the electrode sheets 11 may be rectangular, with each layer having the same length and width. Multiple electrode sheets 11 are stacked along the thickness direction of the battery cell. The electrode structure 20 includes multiple stacked electrode tabs 21. Correspondingly, if an electrode sheet 11 is a positive electrode sheet 11, then the corresponding electrode tab 21 is a positive electrode tab 21; if an electrode sheet 11 is a negative electrode sheet 11, then the corresponding electrode tab 21 is a negative electrode tab 21. Each electrode tab 21 includes a first end 211 and a second end 212 disposed opposite to each other, with the first end 211 close to and connected to the corresponding electrode sheet 11. In this embodiment, from one side of the tab structure 20 to the other, the distance between the second end 212 and the first end 211 of the plurality of tabs 21 decreases and then increases. In this embodiment, "decreasing" means showing a continuous decreasing trend, and "increasing" means showing a continuous increasing trend. The magnitude of the decrease or increase can be fixed or not fixed.

[0040] For example, see Figure 1 and Figure 4 Along the thickness direction of the battery cell, the electrode structure 20 includes multiple levels of electrode tabs 21, namely, level 1 electrode tab 25, ..., level i electrode tab 26, ..., level N electrode tab 27. The bare battery cell 10 includes multiple levels of electrode tabs 11, namely, level 1 electrode tab 111, ..., level i electrode tab 112, ..., level N electrode tab 113. Level 1 electrode tab 111 is connected to the first end 211 of level 1 electrode tab 25, level 2 tab is connected to the first end 211 of level i electrode tab 26, and level N electrode tab 113 is connected to the first end 211 of level N electrode tab 27. Since level 1 electrode tab 111, level i electrode tab 112, and level N electrode tab 113 have the same specifications, the first ends 211 of the multiple electrode tabs 21 are located in the working plane.

[0041] From the first-level tab 25 to the i-th-level tab 26, the distance between the first end 211 and the second end 212 of each level of tab 21 decreases. From the i-th tab 21 to the N-th tab 21, the distance between the first end 211 and the second end 212 of each level of tab 21 increases. Here, i is a positive integer greater than 1 and less than N. Each level of tab 21 may include one tab 21 or multiple tabs 21.

[0042] In this embodiment, from one side of the tab structure 20 to the other, the distance between the second end 212 and the first end 211 of the multiple tab pieces 21 decreases and then increases, giving the tab structure 20 a gradient tab feature. Therefore, the size of the tab structure 20 after welding is more suitable and can be directly welded to structures such as connecting pieces or cover plates. No need to cut the tabs, thus eliminating the generation of tab debris. This effectively prevents debris and wire breakage at the tab edges due to poor tab cutting, thereby reducing the probability of tab debris falling into the core package, leading to short circuits, increased self-discharge rate, and reduced capacity in the cell. This significantly improves the cell manufacturing yield, performance, and service life.

[0043] In one embodiment, see Figure 4 , Figure 5 and Figure 6 Pointing from one side of the tab structure 20 to the other side, at least one tab 21 located on one side of the tab structure 20 is a first tab 22, and at least one tab 21 located on the other side of the tab structure 20 is a second tab 23. The distance between the second end 212 and the first end 211 of the first tab 22 is greater than the distance between the second end 212 and the first end 211 of the second tab 23.

[0044] For example, see Figure 4 and Figure 5 Pointing from one side of the tab structure 20 to the other, the first-stage tab 25 on one side of the tab structure 20 includes at least one first tab 22 or a plurality of first tabs 22 of the same size arranged in sequence. The Nth-stage tab 27 on the other side of the tab structure 20 includes at least one second tab 23 or a plurality of second tabs 11 of the same size arranged in sequence. The distance between the second end 212 and the first end 211 of the first tab 22 in the first-stage tab 25 is greater than the distance between the second end 212 and the first end 211 of the second tab 23 in the Nth-stage tab 27.

[0045] In this embodiment, the distance between the two ends of the first tab 22 on one side of the tab structure 20 is set to be greater than the distance between the two ends of the second tab 23 on the other side of the tab structure 20. At a certain convergence height, when the tab structure 20 is converged, the tabs 21 on both sides of the tab structure 20 can be converged and welded, ensuring the feasibility and effectiveness of the welding operation. This avoids the situation where additional cutting of the tab 21 is required due to the larger size of one side, reducing the probability of tab debris caused by cutting the tab 21 and improving the reliability of the battery cell.

[0046] In some embodiments, see Figure 4 , Figure 5 and Figure 6At least one tab 21 with the shortest distance between the second end 212 and the first end 211 is the third tab 24, wherein the number of tabs 21 between the first tab 22 and the third tab 24 is greater than or equal to the number of tabs 21 between the second tab 23 and the third tab 24.

[0047] For example, see Figure 4 , Figure 5 and Figure 6 The i-th stage electrode tab 26 includes at least one third electrode tab 24 or multiple third electrode tabs 24 of the same size arranged in sequence. The first stage electrode tab 25 includes at least one first electrode tab 22 or multiple first electrode tabs 22 of the same size arranged in sequence. The N-th stage electrode tab 27 includes at least one second electrode tab 23 or multiple second electrode tabs 23 of the same size arranged in sequence. The number of electrode tabs 21 between a first electrode tab 22 in the first stage electrode tab 25 that is far from the i-th stage electrode tab 26 and a third electrode tab 24 in the i-th stage electrode tab 26 that is close to the first stage electrode tab 25 is greater than the number of electrode tabs 21 between a second electrode tab 23 in the N-th stage electrode tab 21 that is far from the i-th stage electrode tab 26 and a third electrode tab 24 in the i-th stage electrode tab 26 that is close to the N-th stage electrode tab 27.

[0048] In this embodiment, the tab structure 20 converges at the position of the i-th stage tab 26, and the number of tabs 21 between the first tab 22 and the third tab 24 is greater than or equal to the number of tabs 21 between the second tab 23 and the third tab 24. By adjusting the distribution of the number of tabs 21 between different tabs 21 and the third tab 24, which serves as the convergence reference, the arrangement density of the tabs 21 on both sides is more balanced when the tab structure 20 converges towards the position of the i-th stage tab 26.

[0049] Given that the distance between the two ends of the first electrode tab 22 is greater than that of the second electrode tab 23, this quantity configuration can further match the size difference between the two electrode tabs 21. The larger size of the first electrode tab 22 and the greater number of electrode tabs 21 between it and the third electrode tab 24 can distribute the arrangement pressure caused by the size difference, avoiding problems such as convergence misalignment and welding defects caused by the dual imbalance of size and quantity. At the same time, there is no need to adjust the size of the electrode tabs 21 or add cutting steps, ensuring the stability of the production process.

[0050] In some embodiments, see Figure 4 , Figure 5 and Figure 6 Along the direction from one side perpendicular to the tab structure 20 to the other side, the cross section of the tab structure 20 has a gradient groove, the shape of which can be arc, trapezoid, triangle, etc.

[0051] In this embodiment, along the direction from one side of the tab structure 20 to the other, the distance between the first end 211 and the second end 212 of the tab piece 21 in the tab structure 20 gradually decreases and then increases, forming a gradient groove structure. The shape of the gradient groove can reserve space for buffering when the tab pieces 21 are stacked, avoiding the situation where the tab pieces 21 need to be cut after welding due to the same size of each tab piece 21. The smooth transition of the groove shape, such as arc or trapezoid, reduces local stress concentration when the tabs are brought together, reducing the risk of wrinkling and breakage of the tab pieces 21.

[0052] In some embodiments, see Figure 1 The distance between the second end 212 and the first end 211 of the third pole lug 24 is H3, where 23mm ≤ H3 ≤ 25mm. The value of H3 can be 23mm, 23.4mm, 23.8mm, 24mm, 24.5mm, 25mm, or other unlisted values.

[0053] In this embodiment, the third tab 24 serves as the reference tab 21 for the distance of the tab structure 20. After being brought together, the end of the tab structure 20 furthest from the battery cell can be located in the same longitudinal plane, or slightly offset to the left and right with the third tab 24 as the center. Therefore, the distance between the second end 212 and the first end 211 of the third tab 24 basically determines the distance between the end of the brought together tab structure 20 and the end of the bare battery cell 10. The distance between the second end 212 and the first end 211 of the third tab 24 is set reasonably. If it is less than the set range value, the height of the tab structure 20 will be small, which is not conducive to welding and assembly with the adapter 30 or the cover plate. If the height of the tab structure 20 is large, the installation space of the tab structure 20 will be insufficient, and the tab needs to be further cut. This not only increases the complexity of the process, but may also lead to the generation of tab debris, thereby affecting the overall quality and performance of the product. Therefore, in the design and manufacturing process, it is necessary to accurately control the various parameters of the tab 21 to ensure its effectiveness and reliability in practical applications.

[0054] In some embodiments, see Figure 1 The distance between the second end 212 and the first end 211 of the first pole tab 22 is H1, where 38mm≤H1≤40mm. The value of H1 can be 38mm, 28.6mm, 39mm, 39.4mm, 39.8mm, 40mm or other unlisted values.

[0055] In this embodiment, the first electrode tab 22 converges towards the third electrode tab 24. Therefore, the size design of the first electrode tab 22 is reasonable. If the size design of the first electrode tab 22 is smaller than the set value, the convergence size of the first electrode tab 22 is insufficient. If the size design of the first electrode tab 22 is larger than the set value, the converged size of the first electrode tab 22 is still large, requiring further cutting of the electrode tab, which increases the complexity of the process and may also lead to the generation of electrode tab debris, thereby affecting the overall quality and performance of the product.

[0056] In addition, the first tab 22, as the largest tab 21, also serves as the benchmark for the subsequent tabs 21 to decrease and increase. This avoids stacking breaks when the tabs 21 are brought together due to excessive size differences, and ensures that each tab 21 can fit together layer by layer when the whole is brought together, reducing the risk of poor welding connections.

[0057] In some embodiments, see Figure 1 The distance between the second end 212 and the first end 211 of the second pole tab 23 is H2, where 25mm ≤ H2 ≤ 27mm. The value of H2 can be 25mm, 25.5mm, 26mm, 26.6mm, 27mm or other unlisted values.

[0058] In this embodiment, the size of the second tab 23 is reasonably designed. If the size of the second tab 23 is smaller than the set value, the distance between the second tabs 23 will be insufficient, affecting the performance of the tab structure 20. If the size of the second tab 23 is larger than the set value, the size of the second tab 23 after being gathered will still be large, requiring further cutting of the tabs, increasing the complexity of the process, and potentially leading to the generation of tab debris, thereby affecting the overall quality and performance of the product.

[0059] Furthermore, the dimensions of H1 range from 38-40mm, H2 from 25-27mm, and H3 from 23-25mm, forming a smooth decreasing gradient in size from H1 to H3 and from H2 to H3. H1, as the largest tab 21, has a size difference of 12-15mm with H2 and 13-17mm with H3, avoiding "stack discontinuity" during tab assembly due to excessive size differences. This ensures that each tab 21 fits together layer by layer during overall assembly, reducing the risk of incomplete welding connections. Simultaneously, the specific values ​​of H1 and H2 provide dimensional flexibility for different operating conditions, adapting to diverse tab stacking requirements.

[0060] In some embodiments, the multiple tabs 21 on both sides of the tab structure 20 converge and adhere to the third tab 24.

[0061] For example, when the i-th stage electrode 112 includes a third electrode tab 24, the electrode tabs 21 from the first stage electrode 25 to the (i-1)-th stage electrode 21 all converge toward one side of the third electrode tab 24, and each layer of electrode tabs 21 is bonded together. The n-th stage electrode tabs 21 to the (i+1)-th stage electrode tabs 21 have successively greater distances toward the third electrode tab 24, and each layer of electrode tabs 21 is bonded together. After all the electrode tabs 21 are converged and bonded together, a pre-welding operation is performed.

[0062] For example, when the i-th electrode 112 includes multiple third electrode tabs 24, the third electrode tab 24 located in the middle is used as the reference electrode tab 21, the third electrode tab 24 closest to the second electrode tab 23 is used as the reference tab, or the third electrode tab 24 closest to the first electrode tab 22 is used as the reference electrode tab 21. The tabs located on both sides of the reference tab converge towards the reference tab side, so that each layer of tabs fits together.

[0063] In this embodiment, the third tab 24 is used as the reference tab, and the distance between the other tabs 21 and the reference tab 21 is controlled. This reduces the probability of some tabs 21 breaking due to excessive bending and tension, and improves the reliability of the tab structure 20.

[0064] In some embodiments, see Figure 3 The distance between the gathered third electrode tab 24 and the plane containing the bottom of the bare cell 10 is L, where 5mm≤L≤7mm. The value of L is 5mm, 5.5mm, 5.8mm, 6mm, 6.5mm, 7mm or other unlisted values.

[0065] For example, when the i-th electrode 112 includes multiple third electrode tabs 24, the third electrode tab 24 located in the middle is used as the reference tab, the third electrode tab 24 closest to the second electrode tab 23 is used as the reference tab, or the third electrode tab 24 closest to the first electrode tab 22 is used as the reference tab 21. In this embodiment, the distance between the converged third electrode tab 24 and the plane where the bottom of the core package is located refers to the distance between the lower surface of the third electrode tab 24 serving as the reference tab and the plane where the bottom of the core package is located.

[0066] For example, when the i-th stage tab 26 includes a third stage tab 24, the distance between the lower surface of the third stage tab 24 and the plane containing the bottom of the core package.

[0067] Understandably, with a fixed distance between the first tab 22 and the second tab 23, the smaller the distance between the third tab 24 and the plane containing the bottom of the bare cell 10, the greater the bending radius of the first tab 22, making it prone to breakage after bending and tightening. Conversely, the greater the distance between the third tab 24 and the plane containing the bottom of the bare cell 10, the greater the bending radius of the second tab 23, making it prone to breakage after bending and tightening. Furthermore, the tab structure 20 is prone to collapsing into the cell, affecting cell performance. In this embodiment, the design of the distance between the gathered third tab 24 and the plane containing the bottom of the bare cell 10 balances the bending radius and size requirements of the first tab 22 and the second tab 23, improving the reliability of the cell.

[0068] In some embodiments, see Figure 2 It also includes an adapter piece 30, and the tab structure 20 that is brought together and fitted is welded to the adapter piece 30.

[0069] In this embodiment, the tab structure 20 that is brought together and attached is welded to the adapter piece 30, and then the adapter piece 30 is welded to the battery cover plate, which is simple to operate.

[0070] In some embodiments, each electrode 11 is integrally die-cut with the corresponding tab 21.

[0071] In this embodiment, each electrode sheet 11 and electrode tab 21 are integrally die-cut, which facilitates the processing and forming of the electrode sheet 11 and electrode tab 21.

[0072] In some embodiments, the tab structure 20 is a positive tab structure and / or a negative tab structure.

[0073] For example, in this embodiment, the tab structure 20 can be a positive tab structure, and the corresponding adapter piece 30 is an aluminum adapter piece 30. Alternatively, the tab structure 20 can be a negative tab structure, and the corresponding adapter piece 30 is a copper adapter piece 30. This eliminates the need to cut the positive and / or negative tabs, improving battery electrical performance and safety.

[0074] In some embodiments, see Figure 4 and Figure 6 From one side of the tab structure 20 to the other, the distances between the second end 212 and the first end 211 of the plurality of tabs 21 decrease in a geometric sequence.

[0075] For example, from the first-level electrode tab 25 to the i-th-level electrode tab 26, the distance difference between the second end 212 and the first end 211 of adjacent electrode tabs 21 is the same, decreasing in a geometric progression. The first-level electrode tab 25 or the i-th-level electrode tab 26 may include one electrode tab 21 or multiple electrode tabs 11, and the distance between the first end 211 and the second end 212 of the multiple electrode tabs 21 in the same level is the same.

[0076] In the embodiments of this application, see Figure 4 and Figure 6 From one side of the tab structure 20 to the other, the distances between the second end 212 and the first end 211 of the multiple tab pieces 21 decrease in a geometric progression. This simplifies the manufacturing process; the regularly decreasing dimensions can be adapted to standardized molds and automated cutting, eliminating the need to adjust parameters individually for each tab, significantly reducing processing complexity and improving efficiency. The uniform decreasing ratio ensures even force distribution when the tab pieces 21 are brought together, avoiding excessive stretching or compression in certain areas due to size differences. This ensures overall structural stability after gathering, with deformation conforming to design standards, laying the foundation for precise welding to the adapter piece 30 and efficient current conduction within the battery.

[0077] In some embodiments, see Figure 4 and Figure 6 From one side of the tab structure 20 to the other, the distances between the second end 212 and the first end 211 of the multiple tabs 21 increase in a geometric sequence.

[0078] For example, from one side of the tab structure 20 to the other, from the first-level tab 25 to the i-th-level tab 26, the distance between the second end 212 and the first end 211 of the tab 21 decreases in a geometric progression; from the i-th-level tab 26 to the N-th level, the distance between the second end 212 and the first end 211 of the tab 21 increases in a geometric progression. When each level of tab 21 includes multiple tabs 21, the distance between the second end 212 and the first end 211 of the multiple tabs 21 located in the same level is the same.

[0079] In this embodiment, multiple tabs 21 increase in size proportionally. This regular size allows for standardized mold development and automated processing, eliminating the need to set individual cutting parameters for each tab, reducing adjustment time and operational complexity, and improving batch processing efficiency. Precise control of the aggregation deformation, along with the uniform increasing ratio, ensures balanced stress across all areas when multiple tabs 21 are aggregated. This effectively prevents excessive local stretching or compression deformation caused by irregular dimensions, ensuring a neat overall structure after aggregation, with deformation strictly meeting design requirements. This provides reliable structural support for subsequent precise alignment and welding with the adapter 30, and for ensuring stable current conduction within the battery.

[0080] In some embodiments, seeFigure 5 The fixed value of the geometric progression between the second end 212 and the first end 211 of the tab 21 is ΔH, where 0 < ΔH ≤ 1 mm. ΔH can be 0.1 mm, 0.3 mm, 0.6 mm, 0.8 mm, 1 mm, or other unlisted values.

[0081] In some embodiments, see Figure 5 The fixed value of the geometric progression between the second end 212 and the first end 211 of the tab 21 is ΔH, where 0 < ΔH ≤ 1 mm. ΔH can be 0.2 mm, 0.3 mm, 0.5 mm, 0.7 mm, 1 mm, or other unlisted values.

[0082] In this embodiment, the fixed values ​​of the geometric progression decreasing or proportional progression increasing between the second end 212 and the first end 211 of the tab 21 are available in multiple options, which can adapt to the spatial layout of different batteries and reduce the cost of customization. A fixed and reasonable range of ΔH ensures that the force on the tab 21 remains stable when it is brought together, avoiding excessive deformation due to excessively large values ​​or affecting structural compactness due to excessively small values.

[0083] In some embodiments, from one side of the tab structure 20 to the other, the fixed value of the distance between the second end 212 and the first end 211 of the plurality of tabs 21 decreasing in a geometric sequence is the same as or different from the fixed value of the distance between the second end 212 and the first end 211 of the plurality of tabs 21 increasing in a geometric sequence.

[0084] Secondly, embodiments of this application also provide a battery, including a battery cell comprising any of the above-described features. This battery possesses all the beneficial effects of the aforementioned battery cells, which will not be elaborated upon further herein.

[0085] Thirdly, embodiments of this application also provide a method for preparing a battery, comprising the following steps:

[0086] S1, based on the distance between the first end 211 and the second end 212 of the tab 21 corresponding to each layer of electrode 11, an integral structure of each layer of electrode 11 and tab 21 is prepared by die cutting;

[0087] S2, the integrated electrode sheet 11 and electrode tab 21 are stacked to form a battery cell. The battery cell includes a bare battery cell 10 and an electrode tab structure 20. The bare battery cell 10 includes multiple stacked electrode sheets 11. The electrode tab structure 20 includes multiple stacked electrode tabs 21. Each electrode tab 21 includes a first end 211 and a second end 212 that are disposed opposite to each other. The first end 211 is close to and connected to the corresponding electrode sheet 11. The distance between the second end 212 and the first end 211 of the multiple electrode tabs 21 decreases and then increases.

[0088] S3, multiple tabs 21 that bring together the battery cells;

[0089] S4, weld multiple tabs 21 to prepare the battery described above.

[0090] In step S4, welding multiple electrode tabs 21 includes pre-welding the multiple electrode tabs 21, followed by welding the electrode tab structure 20 and the adapter piece 30 together. Both welding processes employ ultrasonic welding.

[0091] Compared to related technologies where the tabs 21 are pre-welded together and then cut to ensure the tab structure 20 meets the requirements for connecting the connecting piece and the cover plate, this embodiment eliminates the need to cut the tab structure 20 after welding. This not only avoids the problems caused by cutting but also reduces the amount of battery fabrication and improves battery manufacturing efficiency.

[0092] In the description of this application, 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. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0093] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0094] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0095] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A battery cell, characterized in that, include: The bare cell (10) includes multiple stacked electrode sheets (11); The electrode structure (20) includes a plurality of stacked electrode pieces (21). Each electrode piece (21) includes a first end (211) and a second end (212) disposed opposite to each other. The first end (211) is close to and connected to the corresponding electrode piece (11) and points from one side of the electrode structure (20) to the other side. The distance between the second end (212) of the plurality of electrode pieces (21) and the first end (211) decreases and then increases.

2. The battery cell according to claim 1, characterized in that, Pointing from one side of the tab structure (20) to the other side, at least one tab (21) on one side of the tab structure (20) is a first tab (22), and at least one tab (21) on the other side of the tab structure (20) is a second tab (23). The distance between the second end (212) of the first tab (22) and the first end (211) is greater than the distance between the second end (212) of the second tab (23) and the first end (211).

3. The battery cell according to claim 2, characterized in that, At least one of the tabs (21) with the shortest distance between the second end (212) and the first end (211) is the third tab (24), wherein the number of tabs (21) between the first tab (22) and the third tab (24) is greater than or equal to the number of tabs (21) between the second tab (23) and the third tab (24).

4. The battery cell according to claim 3, characterized in that, The distance between the second end (212) and the first end (211) of the third pole tab (24) is H3, where 23≤H3≤25mm.

5. The battery cell according to claim 3 or 4, characterized in that, The multiple tabs (21) on both sides of the tab structure (20) converge and adhere to the third tab (24).

6. The battery cell according to claim 5, characterized in that, The distance between the gathered third electrode tab (24) and the plane at the bottom of the bare cell (10) is L, where 5mm≤L≤7mm.

7. The battery cell according to claim 5, characterized in that, It also includes an adapter piece (30), and the tab structure (20) that is brought together and fitted is welded to the adapter piece (30).

8. The battery cell according to claim 2, characterized in that, The distance between the second end (212) and the first end (211) of the first electrode tab (22) is H1, wherein 38mm≤H1≤40mm.

9. The battery cell according to claim 2, characterized in that, The distance between the second end (212) and the first end (211) of the second pole tab (23) is H2, wherein 25mm≤H2≤27mm.

10. The battery cell according to any one of claims 1 to 4, characterized in that, Each layer of the electrode sheet (11) and the corresponding electrode tab (21) are integrally die-cut.

11. The battery cell according to any one of claims 1 to 4, characterized in that, The electrode structure (20) is a positive electrode structure and / or a negative electrode structure.

12. The battery cell according to any one of claims 1 to 4, characterized in that, From one side of the electrode structure (20) to the other side, the distances between the second ends (212) and the first ends (211) of the plurality of electrode pieces (21) decrease in a geometric sequence. And / or, from one side of the tab structure (20) to the other side, the distances between the second ends (212) and the first ends (211) of the plurality of tabs (21) increase in a geometric sequence.

13. The battery cell according to claim 12, characterized in that, The fixed value of the geometric series decreasing between the second end (212) and the first end (211) of the electrode tab (21) is ΔH, where 0≤ΔH≤1mm; And / or, the fixed value of the geometric progression between the second end (212) and the first end (211) of the tab (21) is ΔH, where 0≤ΔH≤1mm.

14. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 13.

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