Battery cells and batteries

Abstract

This utility model provides a battery cell and a battery. The battery elevator includes a top cover and tabs. The top cover has a terminal post. The tabs are electrically connected to the terminal posts. The terminal posts and the tabs are directly connected by through-welding. This direct connection between the terminal posts and the tabs helps to configure a larger capacity cell structure within a limited size, improving the utilization efficiency of the internal space. As a result, the energy that the battery can store and release per unit volume increases accordingly, which is conducive to achieving higher energy density and thus meeting the performance requirements of application scenarios such as high range and high power density.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to a battery cell and a battery. Background Technology

[0002] Power batteries, as energy conversion devices that convert chemical energy into electrical energy, are widely used in consumer electronics, transportation, energy storage systems, and industrial equipment. In recent years, with the rapid development of electric vehicles and renewable energy systems, the market demand for high-performance power batteries has continued to grow.

[0003] However, in related technologies, the energy density of power batteries still has certain limitations and is still difficult to meet the usage requirements of scenarios such as high range and high power density. Utility Model Content

[0004] The embodiments of this utility model provide a battery cell and a battery, which can improve the energy density of the battery to a certain extent.

[0005] In a first aspect, embodiments of the present invention provide a battery cell, comprising:

[0006] Top cover, with pole; and

[0007] The tab is electrically connected to the electrode post;

[0008] The electrode post and the electrode tab are directly connected by through-welding.

[0009] By adopting the above technical solution, the terminals and tabs are directly connected via through-welding, eliminating the space occupied by connecting pieces or transition connections in related structures. This frees up more internal battery space to accommodate the cell pack, enabling the configuration of larger capacity cell structures within a limited size and improving the utilization efficiency of internal space. Consequently, the energy that the battery can store and release per unit volume increases, facilitating the achievement of higher energy density and meeting the performance requirements of applications such as high range and high power density.

[0010] In one embodiment, the weld of the through weld extends through the stack of the pole post and the tab.

[0011] By adopting the above technical solution, the heat-affected zone of the through-weld is narrower, which helps to reduce the thermal impact on adjacent battery active materials and lower the risk of material performance degradation. Simultaneously, the regular weld seam shape of the through-weld provides favorable conditions for integrating a uniform heat dissipation structure at the electrode post, facilitating improved overall thermal management capabilities. The through-weld seam penetrates the laminated structure of the electrode post and the tab, giving the welded area high structural strength. Its shear resistance can reach 80% to 95% of the base material, helping to suppress electrode expansion caused by rapid lithium-ion insertion / extraction during high-rate charging and discharging, thereby reducing the risk of electrode delamination or weld failure to a certain extent.

[0012] In one embodiment, the welded portion of the through-weld forms a weld solidified portion, which has a nail-head-shaped geometric profile.

[0013] By adopting the above technical solution, the weld has a nail-head-shaped geometric profile and a regular welding shape, which is conducive to integrating a uniform heat dissipation structure at the electrode post, thereby improving the thermal management capability of the battery.

[0014] In one embodiment, the weld height H of the through weld and the opening width Wf of the through weld on the pole side satisfy: H>3×Wf.

[0015] By adopting the above technical solution, the depth of the weld is greater than the width of the opening, which is conducive to forming a fully fused welded connection structure, thereby improving the welding strength and connection reliability.

[0016] In one embodiment, the weld seam of the through weld protrudes from the outer surface of the pole post.

[0017] By adopting the above technical solution, the weld seam forms an outward convex structure, which is conducive to external identification and quality inspection of the welded part. It also facilitates subsequent structural docking with heat dissipation structure or other functional components, thereby improving the overall integration efficiency.

[0018] In one embodiment, the welded portion of the through-weld forms a weld solidification portion, and the height Hr of the weld solidification portion protruding from the surface of the pole post satisfies: Hr ≤ 0.2 × Wf, where:

[0019] Wf is the opening width of the weld seam of the penetration weld on the pole side.

[0020] By adopting the above technical solution, the height of the weld protrusion can be effectively controlled, which not only ensures the welding strength, but also helps to maintain the structural flatness of the outer surface of the electrode post, thereby facilitating the subsequent integration of heat dissipation structures or sealing components and improving the battery packaging accuracy and thermal management efficiency.

[0021] In one embodiment, the electrode tab forms a protrusion and / or a depression in the weld area of ​​the through-weld.

[0022] By adopting the above technical solution, the micro-geometric deformation formed by the electrode in the welding area helps to release the stress concentration generated during the welding process, thereby improving the structural stability and long-term service reliability of the welded joint.

[0023] In one embodiment, the height of the protrusion h1 ≤ 5 μm; and / or,

[0024] The depth of the depression h2 is ≤ 3 μm.

[0025] By adopting the above technical solution and controlling the size range of the micro-morphology of the welding area, it is helpful to avoid affecting the conductivity of the electrode tab or causing local stress damage due to excessive deformation, thereby further improving the consistency and electrical performance stability of the welded structure.

[0026] In one embodiment, the electrode post includes a negative electrode post, which comprises a first metal layer and a second metal layer stacked and interconnected.

[0027] By adopting the above technical solution, the negative electrode post adopts a multi-metal layer structure, which is conducive to combining the advantages of different metal materials in terms of conductivity, corrosion resistance or mechanical properties, thereby improving the overall performance of the electrode post and meeting the dual requirements of electrical stability and structural reliability in complex working environments.

[0028] In one embodiment, an intermetallic compound layer is formed at the contact surface of the first metal layer and the second metal layer during welding, and the thickness of the intermetallic compound layer is ≤2μm.

[0029] By adopting the above technical solutions, the thickness of the intermetallic compound layer can be effectively controlled within a reasonable range, maintaining the mechanical strength and electrical conductivity of the welded joint, and improving the overall welding quality and structural stability.

[0030] In one embodiment, the first metal layer comprises a pure copper layer or a copper alloy layer; and / or,

[0031] The second metal layer includes an aluminum layer or an aluminum alloy layer.

[0032] By adopting the above technical solution, combining the excellent conductivity of the copper layer with the lightweight and cost advantages of the aluminum layer, the performance of the electrode post is optimized, which is beneficial to improving the electrical performance and structural stability of the battery, while also helping to reduce manufacturing costs.

[0033] In one embodiment, an insulating sheet is also included, the insulating sheet being located on the top cover away from the tab side.

[0034] By adopting the above technical solutions, the installation of insulating sheets helps to improve the insulation performance of individual battery cells, reduce electrical interference or short-circuit risks between the tabs and the top cover and other components, thereby enhancing the safety and reliability of the battery.

[0035] Secondly, embodiments of this utility model provide a battery comprising the battery cell described in the above technical solution.

[0036] By adopting the above technical solutions, it is beneficial to improve the overall energy density and reliability of the battery pack.

[0037] The beneficial effects of the embodiments of this utility model are as follows:

[0038] In embodiments of this invention, by directly connecting the electrode post and the electrode tab using through-welding, the space occupied by connecting pieces or transition connections in related structures is eliminated. This frees up more internal battery space to accommodate the cell pack, thereby enabling the configuration of larger capacity cell structures within a limited size range and improving the utilization efficiency of internal space. Consequently, the energy that the battery can store and release per unit volume increases, facilitating the achievement of higher energy density and meeting the performance requirements of applications such as high range and high power density. Simultaneously, through-welding enables metallurgical bonding between metals, resulting in a dense weld structure free of pores and significantly reduced contact resistance, which helps reduce internal battery resistance and improves the overall electrical performance and operating efficiency of the battery. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is an exploded view of a single battery cell provided in an embodiment of this utility model;

[0041] Figure 2 This is a three-dimensional schematic diagram of a battery cell provided in an embodiment of this utility model;

[0042] Figure 3 This is a partial cross-sectional view of a battery cell provided in an embodiment of this utility model.

[0043] Explanation of reference numerals in the attached figures:

[0044] 100, Top cover; 110, Terminal post; 111, Negative terminal post; 111a, First metal layer; 111b, Second metal layer; 200, Tab; 300, Insulating sheet. Detailed Implementation

[0045] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present utility model. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of the present utility model and are not intended to limit the present utility model. In the present utility model, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0046] Firstly, referring to Figures 1 to 3 This utility model provides a battery cell, including a top cover 100 and a tab 200. In some embodiments, the top cover 100 includes a terminal post 110, which is electrically connected to the tab 200. Exemplarily, the terminal post 110 and the tab 200 are welded together.

[0047] As a crucial conductive component of the battery cell, the terminal 110 is responsible for current extraction, and its electrical connection with the tab 200 significantly impacts battery performance. A stable electrical connection is achieved between the terminal 110 and the tab 200 through welding.

[0048] It should be understood that in this embodiment, "terminal post 110" refers to the protruding conductive component on the top cover 100, and "terminal tab 200" refers to the conductive sheet connecting the battery cell pack and the external circuit. The two are connected by through-welding to achieve electrical and mechanical integration.

[0049] In some embodiments, the terminal post 110 and the tab 200 are directly connected by through-welding. By employing through-welding, the space occupied by connecting pieces or transition connections in traditional structures is eliminated, freeing up more internal battery space to accommodate the cell pack. This allows for the configuration of larger capacity cell structures within a limited size range, improving the utilization efficiency of internal space. Consequently, the energy that the battery can store and release per unit volume increases, facilitating the achievement of higher energy density and meeting the performance requirements of applications such as high range and high power density.

[0050] In addition, penetration welding can achieve metallurgical bonding between metals, resulting in a dense weld structure without pores and significantly reduced contact resistance, which helps to reduce battery internal resistance and improve overall electrical performance and working efficiency.

[0051] In one embodiment, the through-weld penetrates the stack of the electrode post 110 and the tab 200. The narrow heat-affected zone of the through-weld reduces the thermal impact on adjacent battery active materials, lowering the risk of material performance degradation. Simultaneously, the regular weld shape provides favorable conditions for integrating a uniform heat dissipation structure at the electrode post 110, facilitating improved overall thermal management. The through-layer structure gives the welded area high mechanical strength, with shear resistance reaching 80% to 95% of the base material. This helps suppress electrode expansion caused by rapid lithium-ion insertion or extraction during high-rate charging and discharging, thereby reducing the risk of electrode delamination or weld failure to some extent.

[0052] In one embodiment, the welded portion of the through-weld forms a weld solidification zone with a nail-head-shaped geometric profile. It can be understood that the weld solidification zone refers to the solid bonded area formed when the metal material in the weld area is heated to a molten state during the through-weld process and then solidifies as the weld cools. This nail-head-shaped geometry gives the weld a relatively regular and prominent structural feature.

[0053] From a structural perspective, the nail-head-shaped weld fusion section, through its geometry, helps to improve the mechanical bonding strength and stability of the welded connection. The relatively regular weld shape facilitates the integration of a uniform heat dissipation structure at the electrode post 110, providing convenience for battery thermal management, helping to maintain the uniformity of battery operating temperature, and improving the overall performance of the battery.

[0054] In one embodiment, the weld height H of the through-weld and the opening width Wf of the through-weld on the electrode post 110 side satisfy: H > 3 × Wf. Since the depth of the weld is significantly greater than its opening width, it facilitates the formation of a fully fused welded connection structure between the electrode post 110 and the tab 200, thereby improving weld strength and connection reliability. Furthermore, this structure helps reduce welding defects, enhances overall mechanical properties, and is beneficial for the stable operation of the battery under high-rate charge and discharge conditions.

[0055] In one embodiment, the weld seam of the through weld protrudes from the outer surface of the pole post 110. This protruding portion of the weld seam is a raised area formed on the surface of the pole post 110 after the molten metal cools and solidifies during the welding process. The protruding shape of the weld seam can facilitate external identification and quality inspection of the welded area to a certain extent, and helps to quickly determine whether the welding is completed and whether the weld seam is continuous and complete.

[0056] From a structural perspective, the protruding weld seam provides a physical reference for subsequent processes, facilitating mechanical docking and fixation with heat dissipation structures or other functional components, and promoting integrated design and close cooperation of the overall structure. Simultaneously, this protruding weld seam structure may have a positive impact on the heat dissipation contact surface, helping to improve heat conduction efficiency and enhance the battery's thermal management capabilities.

[0057] In one embodiment, the welded portion of the through-weld forms a weld solidification part, and the height Hr of the weld solidification part protruding from the surface of the electrode post 110 satisfies: Hr ≤ 0.2 × Wf, where Wf is the opening width of the through-weld on the electrode post 110 side. By controlling the protrusion height of the weld solidification part within this range, mechanical interference or assembly difficulties caused by excessive weld protrusion can be avoided to a certain extent, while maintaining a relatively flat surface structure of the electrode post 110. This moderate protrusion is beneficial to the integration and assembly of subsequent heat dissipation structures or sealing components, facilitating good contact fit, thereby improving the overall accuracy and thermal management efficiency of the battery packaging. In addition, reasonably controlling the weld protrusion size also helps maintain welding strength and connection reliability, reducing potential defects caused by abnormal weld morphology.

[0058] In one embodiment, the tab 200 forms a protrusion and / or a depression in the weld area of ​​the through weld. The protrusion and depression are micro-geometric deformations caused by the shrinkage of molten and cooled metal during the welding process. These micro-geometric deformations help alleviate stress concentration in the weld area to some extent, thereby improving the structural stability of the welded joint. By effectively dispersing welding stress, this structural feature may play a positive role in delaying fatigue damage to the weld and improving long-term service reliability.

[0059] In one embodiment, the protrusion height h1 ≤ 5 μm. This height range helps limit the geometric deformation of the welded area, thereby reducing mechanical stress concentration caused by the protrusion to a certain extent and contributing to maintaining the structural stability and connection reliability of the welded part.

[0060] In one embodiment, the recess depth h2 ≤ 3 μm. By controlling the size range of the microstructure of the welding area, it is beneficial to avoid the adverse effects on the conductivity of the tab 200 or the occurrence of local stress concentration due to excessive deformation, thereby improving the consistency of the welded structure and the stability of its electrical performance to a certain extent.

[0061] In one embodiment, reference is made to Figure 2 , Figure 3 The electrode post 110 includes a negative electrode post 111, which comprises a first metal layer 111a and a second metal layer 111b that are stacked and interconnected. It should be understood that "stacked arrangement" in this embodiment refers to a composite structure in which two or more metal materials are alternately arranged in a layered form and connected by metallurgical or mechanical means. This structure is beneficial for the synergistic effect of different metal properties and allows for flexible adjustment of the thickness and arrangement order of each layer according to design requirements.

[0062] Specifically, the first metal layer 111a can be selected from copper or a copper alloy, which has excellent conductivity, and the second metal layer 111b can be selected from aluminum or an aluminum alloy, which has lightweight properties and good corrosion resistance. In the laminated structure, the copper layer helps to reduce the resistance loss of the electrode 110, and the aluminum layer helps to reduce the overall weight and improve corrosion resistance. By reasonably controlling the thickness ratio and connection method of each metal layer, this multi-metal layer structure may help to improve the overall electrical performance, mechanical strength and environmental adaptability of the electrode 110.

[0063] In one embodiment, an intermetallic compound layer is formed at the contact surface of the first metal layer 111a and the second metal layer 111b during welding, and the thickness of the intermetallic compound layer is ≤2 μm. It should be understood that the "intermetallic compound layer" referred to in this embodiment refers to a brittle or semi-brittle compound phase layer formed at the interface region of two different metals during a metallurgical reaction at high temperature melting and cooling. By controlling the thickness of this layer to within 2 μm, the joint embrittlement phenomenon caused by an excessively thick compound layer can be avoided to a certain extent, while also helping to maintain the electrical conductivity and mechanical strength of the welded joint.

[0064] Specifically, a thinner intermetallic compound layer can ensure good atomic diffusion bonding, forming a dense transition zone between the weld and the base material, and can also reduce interfacial resistance, which is beneficial to improving the conductivity stability of the weld area. At the same time, the compound layer in this thickness range has little impact on the tensile and shear properties of the joint, which helps to maintain the reliability and long-term service stability of the weld structure under cyclic loading.

[0065] In one embodiment, the first metal layer 111a comprises a pure copper layer or a copper alloy layer. It should be understood that, in this embodiment, "pure copper layer" refers to a conductive layer made of high-purity copper material, while "copper alloy layer" refers to an alloyed copper layer in which small amounts of other metallic elements are added to improve mechanical properties or corrosion resistance. This copper layer, with its excellent conductivity, reduces the resistance loss of the electrode 110 to a certain extent. Combined with the lightweight and cost advantages of the second metal layer 111b (e.g., an aluminum layer or an aluminum alloy layer), this multi-metal layer structure is beneficial for optimizing the overall performance of the electrode 110, including electrical performance and structural stability, while also helping to reduce manufacturing costs.

[0066] In one embodiment, the second metal layer 111b comprises an aluminum layer or an aluminum alloy layer. It should be understood that, in this embodiment, "aluminum layer" refers to a conductive layer made of pure aluminum, while "aluminum alloy layer" refers to an alloyed aluminum layer with appropriate alloying elements added to improve strength or corrosion resistance. The lightweight properties of the aluminum layer help reduce the overall weight of the electrode post 110, while the aluminum alloy layer has advantages in terms of cost and processing technology. Combined with the excellent conductivity of the first metal layer 111a, this multi-metal layer structure achieves complementary performance to a certain extent: the copper layer is mainly responsible for reducing resistance loss, while the aluminum layer or aluminum alloy layer is beneficial for reducing weight and controlling costs. Therefore, this composite structure may help improve the electrical performance and structural stability of the battery, while also having a better controllable manufacturing cost.

[0067] In one embodiment, an insulating sheet 300 is also included, located on the side of the top cover 100 opposite to the tab 200. Exemplarily, the insulating sheet 300 comprises a sheet-like member made of an electrically insulating material (e.g., polyimide, polytetrafluoroethylene, or silicone rubber). By providing this insulating sheet 300 on the side of the top cover 100 opposite to the tab 200, electrical contact between the tab 200 and the top cover 100 and other metal components can be isolated to a certain extent, thereby reducing the risk of electrical interference or micro-discharge and improving the insulation performance of the individual battery cell. Simultaneously, the flexibility of the insulating sheet 300 helps compensate for dimensional deviations during assembly, potentially contributing to a more reliable sealing fit and stability during long-term use.

[0068] This embodiment achieves a direct through-weld connection between the top cover 100 and the tab 200, reducing the internal space occupied by traditional connecting components. This improves the utilization rate of the battery's internal space and, to some extent, increases the battery's energy density, with an expected overall energy density increase of approximately 8% to 10%, making it suitable for highly integrated designs. The through-weld process generates a narrow heat-affected zone, limiting thermal damage to adjacent battery active materials. Furthermore, the regular weld shape facilitates the integration of a uniform heat dissipation structure, enhancing the battery's thermal management performance. The weld depth fully penetrates the terminal post 110 and the tab 200, achieving a shear strength of 80% to 95% of the base material. This helps mitigate the risk of electrode expansion and delamination caused by rapid lithium-ion insertion or extraction during high-rate charging and discharging. In addition, through-welding achieves metallurgical bonding, resulting in a dense, pore-free weld that significantly reduces contact resistance to 1 / 5 to 1 / 10 of that of traditional spot welding. This effectively reduces battery internal resistance and improves overall electrical performance and efficiency.

[0069] It is understood that the penetration welding mentioned in this embodiment refers to a welding process that uses a laser or other high-energy-density heat source to achieve local melting and form a through weld seam through the laminated metal materials of the electrode post 110 and the tab 200. This process enables the weld seam to completely penetrate the laminated structure of the connecting components, forming a dense welded area with metallurgical bonding, thereby meeting the application requirements of the battery cell in terms of mechanical strength and electrical performance.

[0070] Secondly, embodiments of this utility model provide a battery, including the battery cell described in the above embodiments. This battery possesses all the beneficial effects of the aforementioned battery cell, which will not be repeated here.

[0071] The embodiments of this utility model have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A battery cell, characterized in that, include: Top cover (100), having pole post (110); and The tab (200) is electrically connected to the pole post (110); The pole post (110) and the tab (200) are directly connected by through welding.

2. The battery cell according to claim 1, characterized in that, The weld seam of the penetration weld extends through the stack of the pole post (110) and the tab (200).

3. The battery cell according to claim 1, characterized in that, The welded portion of the penetration weld forms a weld solidified part, which has a nail-head-shaped geometric profile.

4. The battery cell according to claim 1, characterized in that, The weld height H of the penetration weld and the opening width Wf of the penetration weld on the pole post (110) side satisfy: H > 3×Wf.

5. The battery cell according to any one of claims 1-4, characterized in that, The weld seam of the penetration weld protrudes from the outer surface of the pole post (110).

6. The battery cell according to claim 5, characterized in that, The welded portion of the penetration weld forms a weld solidified part, and the height Hr of the weld solidified part protruding from the surface of the pole post (110) satisfies: Hr≤0.2×Wf, where: Wf is the opening width of the weld seam of the penetration weld on the pole post (110) side.

7. The battery cell according to any one of claims 1-4, characterized in that, The tab (200) forms a protrusion and / or a depression in the weld area of ​​the through weld.

8. The battery cell according to claim 7, characterized in that, The height of the protrusion h1 ≤ 5 μm; and / or, The depth of the depression h2 is ≤ 3 μm.

9. The battery cell according to any one of claims 1-4, characterized in that, The electrode post (110) includes a negative electrode post (111), which comprises a first metal layer (111a) and a second metal layer (111b) that are stacked and interconnected.

10. The battery cell according to claim 9, characterized in that, An intermetallic compound layer is formed at the contact surface between the first metal layer (111a) and the second metal layer (111b) during welding, and the thickness of the intermetallic compound layer is ≤2μm.

11. The battery cell according to claim 9, characterized in that, The first metal layer (111a) comprises a pure copper layer or a copper alloy layer; and / or, The second metal layer (111b) includes an aluminum layer or an aluminum alloy layer.

12. The battery cell according to any one of claims 1-4, characterized in that, It also includes an insulating sheet (300) located on the side of the top cover (100) away from the tab (200).

13. A battery, characterized in that, Includes the battery cell as described in any one of claims 1 to 12.

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