Battery cell structure and secondary battery

Abstract

The application relates to a novel battery cell structure and a secondary battery. The cell structure is divided into a first side and a second side by a uniform division line in the thickness direction, a plurality of groups of tabs with different polarities are arranged on the two sides respectively, tabs with the same polarity are staggered and do not intersect, each tab can have 20%-50% overlap, tabs with the same polarity are alternately spaced, and the lengths of tabs in the same group gradually increase towards the division line. On the basis of ensuring the overcurrent area, the cell structure reduces the single-side tab stacking thickness, avoids false welding, improves the welding quality, reduces the failure risk, releases space to increase the active material filling amount, adapts to various production processes, reduces the internal resistance of the overlapping tabs, uniformly dissipates heat, disperses stress through the alternate tabs, and further optimizes the tab size to make the welding surface flat, which is beneficial to production assembly and heat dissipation. The secondary battery comprises the cell structure and a shell, and the use of the cell structure can improve the energy density per unit volume.

Description

Technical Field

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

[0002] In today's energy storage field, lithium-ion batteries, with their excellent electrochemical performance, have been widely used in numerous areas such as digital products, power drives, and energy storage systems. With continuous technological advancements, the market is placing higher demands on the performance of lithium-ion batteries, particularly in terms of energy density, rate discharge capability, and discharge temperature rise control. To meet these growing needs, battery thickness is constantly increasing, and the length and width of the positive and negative electrode plates are also correspondingly expanding.

[0003] Please see Figure 1 , Figure 1 This is a top-view diagram of the existing battery cell structure, where the positive and negative tabs overlap vertically. In this context, continuing to use the traditional single-tab design would increase the battery's internal resistance and cause severe polarization during discharge, impacting its lifespan and safety. Therefore, multi-tab batteries have emerged and are gradually becoming the mainstream trend in the industry. Multi-tab cells offer excellent charging and discharging speeds, demonstrating potential in fast charging technology and high-rate discharge applications. However, the current manufacturing process for multi-tab battery cells still faces many challenges. In the process of overlapping multiple tabs and welding them to the adapter, the conventional approach is to directly weld only the tab closest to the adapter to it, while the other tab layers are connected using resistance welding, ultrasonic welding, or laser welding. When the number of tab layers increases, leading to an increase in the overall thickness of the tabs, the problem of incomplete welds is highly likely, severely affecting welding quality and consequently reducing the overall performance and reliability of the battery. Furthermore, excessively thick unidirectional tabs not only occupy valuable space in the tab direction of the cell but also negatively impact the cell's energy density, limiting further improvements in battery performance. Therefore, developing a multi-tab battery cell manufacturing technology that can address these issues and ensure stable tab welding during the welding process is one of the problems that needs to be solved. Utility Model Content

[0004] The purpose of this application is to provide a battery cell structure that can ensure the current-carrying area of ​​the tabs while reducing the thickness of the tabs, enhancing welding reliability, improving cell safety performance, and reducing the space occupied by the thickness of the tabs. This purpose is achieved through the following technical solution: the battery cell structure includes a first electrode, a second electrode, and a separator between the first electrode and the second electrode;

[0005] The battery cell is divided into a first side and a second side by evenly spaced dividing lines in the thickness direction. The first side includes multiple first tabs electrically connected to the first electrode and multiple third tabs electrically connected to the second electrode. The second side includes multiple second tabs electrically connected to the first electrode and multiple fourth tabs electrically connected to the second electrode. The first tabs and the second tabs do not intersect in the direction perpendicular to the dividing lines, and the third tabs and the fourth tabs do not intersect in the direction perpendicular to the dividing lines.

[0006] The first and second electrodes are electrodes of the same polarity, and the third and fourth electrodes are electrodes of the same polarity; the first electrode and the third electrode have opposite polarities.

[0007] In one embodiment, the first tabs, the second tabs, the third tabs, or the fourth tabs do not intersect.

[0008] In one embodiment, the tabs overlap in a direction perpendicular to the dividing line, with the overlap ratio ranging from 20% to 50%.

[0009] In one embodiment, the electrodes on the same side are alternately spaced.

[0010] In one embodiment, the width and / or height of the tabs within the same group vary in a gradient direction toward the dividing line.

[0011] In one embodiment, the cell structure is formed by winding or stacking.

[0012] In one embodiment, the first electrode is a negative electrode and the second electrode is a positive electrode;

[0013] Alternatively, the first electrode may be a positive electrode and the second electrode may be a negative electrode.

[0014] In one embodiment, the first and second electrodes are located on the same surface, and the third and fourth electrodes are also located on the same surface.

[0015] In one embodiment, the first and second electrodes are welded to the same adapter plate, and the third and fourth electrodes are welded to the same adapter plate.

[0016] In addition, this application also provides a secondary battery, which includes the aforementioned battery cell structure and housing, wherein the battery cell structure is housed within the housing.

[0017] Compared with the prior art, this application has the following beneficial effects:

[0018] This application employs multiple sets of tabs with different polarities on the first and second sides, with each tab positioned in a non-overlapping manner. This staggered arrangement effectively reduces the overall thickness of the tabs while ensuring sufficient current-carrying area. Compared to the traditional method of stacking tabs in one direction, this avoids the problem of excessive thickness due to too many tab layers, thereby reducing the risk of poor tab soldering, enhancing soldering reliability, and ultimately improving the safety performance of the battery cell.

[0019] The reduced thickness of the tabs occupies less space, providing more usable space for the cell design in the tab direction. This allows for more flexible internal cell design, accommodating more active materials or other components, thus improving the cell's energy density and overall performance. Furthermore, the overlapping design enables a more robust connection structure during welding of multiple tabs, reducing the thickness of each individual tab weld and ensuring weld strength. Welding the first and second tabs to the same adapter plate, and the third and fourth tabs to the same adapter plate, simplifies the tab welding process, reduces the number of welds and the welding difficulty, and ensures battery performance stability. This application optimizes tab arrangement, welding process, and space utilization through a unique battery cell structure design. Attached Figure Description

[0020] Figure 1 This is a top view of the existing battery cell structure;

[0021] Figure 2 This is a top view schematic diagram of the cell structure in one embodiment of this application;

[0022] Figure 3 This is a top view schematic diagram of the cell structure in another embodiment of this application;

[0023] Figure 4 This is a top view schematic diagram of the cell structure in another embodiment of this application.

[0024] Explanation of reference numerals in the attached diagram: 100, first pole piece; 110, first tab; 120, third tab; 200, second pole piece; 210, second tab; 220, fourth tab; 300, diaphragm. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, it should be noted that, for ease of description, only the parts relevant to this application are shown in the accompanying drawings, not the entire structure. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this application.

[0026] The terms “comprising” and “having”, and any variations thereof, used in this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the steps or units listed, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] As a core component of lithium-ion batteries, the rationality of the battery cell structure design directly determines the overall performance of the battery. In traditional multi-tab battery cells, the excessive number of tabs overlapping and welding with the adapter often leads to excessive thickness, causing poor soldering. This not only affects welding reliability but also reduces battery life and safety performance. Furthermore, excessive unidirectional tab thickness occupies a significant amount of space in the tab direction, limiting further improvements in cell energy density. To overcome these technical bottlenecks, this application provides a novel battery cell structure. Through a unique tab arrangement, cell segmentation design, and optimized welding scheme, it effectively reduces the space occupied by tab thickness while ensuring tab current flow area, enhancing welding reliability, and improving cell safety performance, thus providing more possibilities for cell design. The following section provides a detailed description of this battery cell structure; please refer to [link / reference]. Figures 2 to 4 As shown, the battery cell structure of this application includes a first electrode 100, a second electrode 200, and a separator 300 between the first electrode 100 and the second electrode 200.

[0029] The battery cell structure is divided into a first side and a second side by evenly spaced dividing lines in the thickness direction. The first side includes a plurality of first tabs 110 electrically connected to the first electrode 100 and a plurality of third tabs 120 electrically connected to the second electrode 200. The second side includes a plurality of second tabs 210 electrically connected to the first electrode 100 and a plurality of fourth tabs 220 electrically connected to the second electrode 200. The first tabs 110 and the second tabs 210 do not intersect in the direction perpendicular to the dividing lines, and the third tabs 120 and the fourth tabs 220 do not intersect in the direction perpendicular to the dividing lines.

[0030] Wherein, the first electrode 110 and the second electrode 210 are electrodes of the same polarity, and the third electrode 120 and the fourth electrode 220 are electrodes of the same polarity; the first electrode 110 and the third electrode 120 have opposite polarities.

[0031] The battery cell structure includes a first electrode 100, a second electrode 200, and a separator 300 sandwiched between the first electrode 100 and the second electrode 200. The separator 300 effectively isolates the positive and negative electrodes while allowing lithium ions to pass freely. Along the thickness direction of the battery cell, the structure is divided into a first side and a second side (not a true structural division) by an evenly spaced dividing line. The first side has multiple first tabs 110 electrically connected to the first electrode 100 and multiple third tabs 120 electrically connected to the second electrode 200. The second side correspondingly has multiple second tabs 210 electrically connected to the first electrode 100 and multiple fourth tabs 220 electrically connected to the second electrode 200. By setting multiple sets of tabs of different polarities on both sides of the battery cell thickness direction, and staggering the tabs of the same polarity on different sides, the first tab 110 and the second tab 210, and the third tab 120 and the fourth tab 220 do not intersect in the direction perpendicular to the dividing line. This effectively reduces the stacking thickness of the tabs on one side while ensuring sufficient current-carrying area. In traditional battery cells, stacking multiple tabs on one side leads to excessively thick tabs, which easily causes poor soldering during welding, affecting welding reliability. The staggered arrangement of this structure avoids this problem, allowing for more uniform application of pressure and heat during welding, improving welding strength and quality, thereby enhancing the stability of the battery during use and reducing the risk of battery failure due to poor welding.

[0032] Reducing the thickness of the tabs and the space occupied is a major advantage of this structure. Due to the staggered arrangement of the tabs, excessive stacking of tabs on one side can be avoided, freeing up more space inside the cell. The extra space can be used to increase the amount of active material. In a battery cell of the same volume, this structure can store more electrical energy.

[0033] This battery cell structure has strong versatility and can adapt to various battery manufacturing processes, such as winding and stacking. In the winding process, the double-sided tab layout ensures the uniform distribution of the tabs during winding, avoids tab twisting or overlapping, and improves winding quality. In the stacking process, the staggered tab arrangement can better match the stacked structure, facilitates the connection and welding of tabs to electrodes, and reduces the difficulty and cost of the manufacturing process.

[0034] In the thickness direction of the battery cell, the cell structure is divided into a first side and a second side by evenly spaced dividing lines. The first side has multiple first tabs 110 electrically connected to the first electrode 100 and multiple third tabs 120 electrically connected to the second electrode 200. The second side has multiple second tabs 210 electrically connected to the first electrode 100 and multiple fourth tabs 220 electrically connected to the second electrode 200. In the direction perpendicular to the dividing lines, not only do tabs of different polarities on the same side (such as the first tab 110 and the third tab 120 on the first side, and the second tab 210 and the fourth tab 220 on the second side) not intersect, but there is also no intersection between the individual first tabs 110, the individual second tabs 210, the individual third tabs 120, and the individual fourth tabs 220.

[0035] In traditional battery cell structures, if the tabs intersect, they interfere with each other during welding, leading to increased thickness and uneven heat distribution. This not only causes defects such as incomplete welds and over-welds, affecting weld strength, but also reduces weld consistency, increasing performance differences between different cells. In this structure, the tabs do not intersect, allowing heat to be distributed more evenly between each tab and the adapter plate during welding, ensuring a strong and stable weld. Tabs are crucial for current conduction and heat generation during battery charging and discharging. When tabs intersect, more localized heat accumulates at the intersection, accelerating the aging and degradation of the tab material and reducing its conductivity. The non-intersecting tabs in this application's structure, through a rational arrangement, reduce the space occupied by the tabs, providing more space for active materials. This results in a more independent and stable structure, effectively resisting external forces.

[0036] In the battery cell structure, the cell is divided into a first side and a second side along the thickness direction by evenly spaced dividing lines. The first side has multiple first tabs 110 electrically connected to the first electrode 100 and multiple third tabs 120 electrically connected to the second electrode 200. The second side correspondingly has multiple second tabs 210 electrically connected to the first electrode 100 and multiple fourth tabs 220 electrically connected to the second electrode 200. The tabs are not completely separated in the direction perpendicular to the dividing lines, but overlap to a certain extent, with this overlap controlled within the range of 20%-50%. When the tabs overlap by 20%-50% in the direction perpendicular to the dividing lines, it is equivalent to increasing the cross-sectional area of ​​the current conduction channel. Reducing the battery's internal resistance can reduce energy loss during current conduction, thereby improving the battery's charging and discharging efficiency. During charging and discharging, the battery generates heat, and the tabs are important components for heat generation and dissipation. When the tabs overlap to a certain extent, heat conduction between the tabs is more uniform. The overlapping portion acts as a bridge for heat conduction, allowing heat to diffuse more quickly from high-temperature areas to low-temperature areas. The aforementioned overlap ratio ensures sufficient heat conduction area without causing localized heat accumulation due to excessive overlap. During battery production, the tabs need to be welded to adapters or other components. When the tabs have a 20%-50% overlap, heat can be distributed more evenly across the overlapping area during welding, resulting in a more stable weld pool. This overlap ratio can also, to some extent, adjust the battery's current carrying capacity.

[0037] In a further technical solution, the tabs on the same side are alternately spaced, with the tabs on the first electrode 100 appearing at intervals. During charging and discharging, the electrode materials expand and contract, generating stress within the cell. If the tabs on the same side are concentrated, stress may concentrate in certain areas, increasing the risk of cell structural damage. Alternating tabs can disperse this stress to some extent, resulting in a more uniform stress distribution within the cell. The alternating arrangement of tabs of different polarities allows the expansion and contraction of the electrode materials to be buffered and balanced in different directions. Improving the structural stability of the cell and reducing problems such as cell deformation and cracking caused by stress concentration is crucial for ensuring the performance and safety of the battery in complex operating environments. Especially when subjected to external forces such as vibration and impact, a uniform stress distribution can enhance the cell's resistance to damage.

[0038] In a further construction of the battery cell, the cell is divided into different regions based on a dividing line that evenly divides the thickness. For the tabs within the same group, the width and / or height are designed to exhibit a gradient change trend towards the dividing line. Specifically, starting from the end of the tabs in this group away from the dividing line, the height of each tab increases sequentially along the direction towards the dividing line. When welding the tabs within this group, the gradual length change design allows the ends of each tab to fit together, resulting in a relatively flat welded surface. The width can also increase sequentially, either simultaneously or independently. During welding, the flat welding surface allows for uniform heat distribution. When the height of the tabs within the same group changes gradient towards the dividing line, the ends of each tab fit tightly together during welding to form a flat surface, improving the strength and stability of the weld. This ensures good electrical and mechanical connections between the tabs and adapters or other connecting components, enabling the battery to withstand frequent charge-discharge cycles and potential external forces such as vibration and impact during long-term use. Furthermore, the aforementioned design facilitates battery production and assembly. During battery production, the smooth welding surface of the tabs simplifies production processes and quality control. A smooth welding surface eliminates the need for additional grinding, correction, or other post-processing steps, reducing production time and costs. Simultaneously, the smooth surface facilitates identification and operation by automated production equipment, improving production efficiency and product consistency. In terms of quality control, a smooth welding surface makes visual inspection and performance testing easier, enabling timely detection and handling of welding defects to ensure product quality.

[0039] A smooth welded surface increases the contact area between the tabs and the heat dissipation components. During battery operation, the tabs are one of the key heat-generating components, and good heat dissipation is crucial for maintaining the battery's normal operating temperature. When the welded surface is smooth, the tabs can fit more tightly with the heat dissipation components such as the heat sink and thermal adhesive, allowing heat to be conducted from the tabs to the heat dissipation components more quickly.

[0040] In a specific embodiment, the cell structure is formed by winding or stacking, with the first electrode 100 being the negative electrode and the second electrode 200 being the positive electrode; or the first electrode 100 being the positive electrode and the second electrode 200 being the negative electrode.

[0041] In a further tab layout, a specific tab distribution method is adopted. Specifically, the first tab 110 and the second tab 210 are located on the same side of the cell, arranged at predetermined intervals and positions. Their position and layout fully consider the uniformity of current distribution within the cell and the convenience of connection with external circuits. Similarly, the third tab 120 and the fourth tab 220 are also located on another side of the cell, opposite or adjacent to the side where the first and second tabs are located (depending on the specific design), arranged at specific intervals and positions. This helps to form a more reasonable current path within the cell. Grouping the tabs on the same side makes the battery easier to handle and arrange during the packaging process. During battery packaging, the tabs need to be connected to the battery casing, adapters, and other components. Tabs on the same side can be concentrated for welding and connection processes, reducing the complexity and difficulty of the operation. At the same time, this layout also facilitates the connection between the battery and external circuits, allowing external circuits to more easily interface with the tabs on the same side.

[0042] In a further technical solution, the first tab 110 and the second tab 210 are welded to the same adapter piece, and the third tab 120 and the fourth tab 220 are welded to the same adapter piece. Welding the first tab 110 and the second tab 210 to the same adapter piece, and the third tab 120 and the fourth tab 220 to another identical adapter piece, allows the current to initially converge at the tab level. During battery charging and discharging, the current generated in the electrode material flows through the tabs to the adapter piece, and multiple tabs connected to the same adapter piece can concentrate the dispersed current. Connecting multiple tabs to the same adapter piece increases the redundancy of the connection, and welding the same group of tabs to the same adapter piece simplifies the connection process in battery assembly. On an automated production line, the welding operation of multiple tabs to the adapter piece can be completed at one time, reducing operation steps and time. In addition, it is also beneficial to the battery's thermal management. As a key component for current convergence and conduction, the adapter piece generates a certain amount of heat during operation. Welding the same group of tabs to the same adapter piece makes the heat distribution on the adapter piece relatively concentrated. This makes it easier to install heat dissipation devices, such as heat sinks and thermal adhesive, on the adapter plate. Through effective heat dissipation design, heat can be quickly conducted away, preventing heat from accumulating inside the battery and improving the overall heat dissipation efficiency of the battery.

[0043] In addition, this application also provides a secondary battery, which includes the aforementioned battery cell structure and housing, wherein the battery cell structure is housed within the housing.

[0044] As described above, this application proposes a battery cell structure comprising a first electrode, a second electrode, and a separator between them. The cell is divided into a first side and a second side along its thickness direction by an evenly spaced dividing line. The first side has multiple first tabs electrically connected to the first electrode and multiple third tabs electrically connected to the second electrode. The second side correspondingly has multiple second tabs electrically connected to the first electrode and multiple fourth tabs electrically connected to the second electrode. The first and second tabs are of the same polarity, as are the third and fourth tabs, with the first and third tabs having opposite polarities. The tabs do not intersect in the direction perpendicular to the dividing line, and the tabs on the same side are alternately spaced. Within the same group, the width and / or height of the tabs gradually change towards the dividing line.

[0045] By arranging multiple sets of tabs with different polarities on both sides in a staggered manner, the current-carrying area is ensured while reducing the stacking thickness of the tabs on one side, avoiding incomplete welding, improving welding strength and quality, and reducing the risk of battery failure. This frees up space for the battery cell, allowing for an increase in the amount of active material filled, thus enhancing energy storage capacity. It also adapts to winding and stacking processes, reducing production difficulty and cost. The overlapping of the tabs can reduce internal resistance, promote uniform heat dissipation, and stabilize welding. The alternating spacing of the tabs can disperse stress and enhance the stability of the battery cell.

[0046] In terms of tab layout, the first and second tabs are located on the same side of the battery cell, while the third and fourth tabs are located on another side of the same cell, facilitating encapsulation and connection to external circuits. Furthermore, the first and second tabs and the third and fourth tabs are each soldered to the same adapter plate, achieving initial current convergence, increasing connection redundancy, and simplifying the assembly process.

[0047] In addition, this application also provides a secondary battery comprising the above-mentioned battery cell structure and casing.

[0048] The above is only one specific implementation of this application, and any other improvements made based on the concept of this application shall be considered within the scope of protection of this application.

Claims

1. A battery cell structure, characterized in that, It includes a first electrode, a second electrode, and a diaphragm between the first electrode and the second electrode; The battery cell is divided into a first side and a second side by evenly spaced dividing lines in the thickness direction. The first side includes multiple first tabs electrically connected to the first electrode and multiple third tabs electrically connected to the second electrode. The second side includes multiple second tabs electrically connected to the first electrode and multiple fourth tabs electrically connected to the second electrode. The first tabs and the second tabs do not intersect in the direction perpendicular to the dividing lines, and the third tabs and the fourth tabs do not intersect in the direction perpendicular to the dividing lines. The first and second electrodes are electrodes of the same polarity, and the third and fourth electrodes are electrodes of the same polarity; the first electrode and the third electrode have opposite polarities.

2. The battery cell structure according to claim 1, characterized in that, The first electrode tabs, the second electrode tabs, the third electrode tabs, and the fourth electrode tabs do not intersect.

3. The battery cell structure according to claim 2, characterized in that, The tabs overlap in the direction perpendicular to the dividing line, with an overlap ratio ranging from 20% to 50%.

4. The battery cell structure according to claim 1, characterized in that, The electrodes on the same side are alternately spaced.

5. The battery cell structure according to claim 1, characterized in that, The width and / or height of the tabs within the same group vary in a gradient direction toward the dividing line.

6. The battery cell structure according to claim 1, characterized in that, The battery cell structure is formed by winding or stacking.

7. The battery cell structure according to claim 6, characterized in that, The first electrode is a negative electrode, and the second electrode is a positive electrode; Alternatively, the first electrode may be a positive electrode and the second electrode may be a negative electrode.

8. The battery cell structure according to claim 7, characterized in that, The first and second pole ears are located on the same plane, and the third and fourth pole ears are also located on the same plane.

9. The battery cell structure according to claim 8, characterized in that, The first and second electrodes are welded to the same adapter plate, and the third and fourth electrodes are welded to the same adapter plate.

10. A secondary battery, characterized in that, Includes the battery cell structure and housing as described in any one of claims 1-9, wherein the battery cell structure is housed within the housing.

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