Single cell and battery pack
By designing an inner tab and a welding extension to form a snap-fit groove in the pouch battery, and having the outer tab extend into the snap-fit groove for connection, the problem of excessive space occupied by the inner and outer tabs is solved, the energy density of the single cell is improved, and the risk of short circuit is reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SVOLT ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2025-03-07
- Publication Date
- 2026-05-12
AI Technical Summary
In existing pouch batteries, the inner and outer tabs extend along the length of the core, occupying a significant amount of internal space and resulting in a low energy density per cell.
Design a single-cell battery structure in which the inner tab includes a fixed base and a welding extension. The welding extension is connected to the thickness direction of the electrode core to form a snap-fit groove. The outer tab extends into the snap-fit groove and connects with the welding extension, thus avoiding the welding of the inner and outer tabs taking up too much space.
By optimizing the tab structure, the energy density of a single cell is increased, and the welding burrs on the outer tabs are prevented from cutting the separator or electrode sheet of the core, thus reducing the risk of short circuit in the core.
Smart Images
Figure CN119994408B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery protection technology, specifically to a single cell and a battery pack. Background Technology
[0002] Soft-pack lithium batteries typically refer to lithium batteries whose outer casing is encapsulated with an aluminum-plastic film. Due to their many advantages, such as light weight, low mold cost, high structural flexibility, high energy density, and high core safety performance, they have been widely used in various fields such as electric vehicles, drones, smart homes, and power banks.
[0003] The existing pouch battery structure mainly consists of an aluminum-plastic film shell, electrode assembly, and outer tabs. The electrode assembly includes the electrode core and inner tabs, while the outer tabs include electrode plates and tab insulating adhesive (injection-molded integrated structure). The aluminum-plastic film is punched out of the cavity to house the electrode assembly using a mold. After the electrode assembly is placed inside the cavity, it is sealed by hot-pressing the aluminum-plastic film edges. Simultaneously, the insulating adhesive of the outer tabs is also hot-pressed during the sealing process of the aluminum-plastic film shell, thus sealing the electrode core. One end of the outer tab is fixed to the inner tab of the electrode assembly by laser welding, while the other end extends outside the aluminum-plastic film shell. The middle is isolated from the aluminum-plastic film shell by the tab insulating adhesive, thereby allowing the current to flow out. Currently, the inner tab extends along the length of the electrode core and is fixed to the outer tab by laser welding, thus allowing the current to flow out of the aluminum-plastic film shell. In this structure, the inner and outer tabs occupy a significant amount of internal space in the pouch battery, resulting in a relatively low overall energy density. Summary of the Invention
[0004] This application provides a single-cell battery and a battery pack, which can solve the technical problem that the inner tab extends along the length of the electrode core, and the outer tab and inner tab occupy a lot of the internal space of the single-cell battery, resulting in a low overall energy density of the single-cell battery.
[0005] This application provides a single-cell battery, which includes an inner tab and an outer tab. One end of the inner tab is connected to the electrode core, and the other end of the inner tab is connected to the outer tab. The electrode core has a first side surface in its length direction and a top surface in its thickness direction. The inner tab includes a fixed base portion and a welding extension portion. The fixed base portion includes a first end portion, a second end portion, and a folded-back position. The first end portion is connected to the first side surface of the electrode core and is disposed adjacent to the top surface of the electrode core. The second end portion is connected to the welding extension portion. The folded-back position is located between the first end portion and the second end portion. A fifth gap is provided between the vertex of the folded-back position in the thickness direction of the electrode core and the top surface of the electrode core. The ratio of the fifth gap to the thickness of the electrode core is 0.026-0.11. The welding extension portion extends along the thickness direction of the electrode core, and a snap-fit groove is formed between the welding extension portion and the first side surface of the electrode core. The outer tab extends into the snap-fit groove and is connected to the welding extension portion.
[0006] In some embodiments, the fifth spacing is 0.3mm-0.6mm, and the thickness of the electrode core is 5.5mm-11.5mm.
[0007] In some embodiments, the outer electrode lug includes a connected welding snap-fit portion and a current lead-out portion, the welding snap-fit portion extending at least partially into the snap-fit groove and connected to the welding extension portion, and the current lead-out portion located outside the snap-fit groove.
[0008] In some embodiments, the welding snap-fit portion extends along the thickness direction of the electrode core, and the current lead-out portion extends along the length direction of the electrode core.
[0009] In some embodiments, the welding method of the welding snap-fit portion and the welding extension portion is laser welding or ultrasonic welding, and the welding snap-fit portion and the welding extension portion are welded to form a weld mark, which is located in the middle of the welding extension portion.
[0010] In some embodiments, when the welding snap-fit portion extends into the snap-fit groove, a first gap is provided between the top of the welding snap-fit portion in the thickness direction of the electrode core and the bottom of the snap-fit groove.
[0011] In some embodiments, the welding snap-fit portion includes an inner snap-fit portion, an outer snap-fit portion, and a connecting portion, wherein the inner snap-fit portion and the outer snap-fit portion both extend along the thickness direction of the electrode core, and the connecting portion connects the inner snap-fit portion and the outer snap-fit portion.
[0012] In some embodiments, the inner snap-fit portion, the outer snap-fit portion, and the connecting portion are all located within the snap-fit groove. The connecting portion is connected to one end of the inner snap-fit portion near the bottom of the snap-fit groove, and the surface of the connecting portion on the side near the bottom of the snap-fit groove is curved.
[0013] In some embodiments, the welding extension is located between the inner snap-fit portion and the outer snap-fit portion, the inner snap-fit portion is located inside the snap-fit groove, and the connecting portion is located outside the snap-fit groove and connected to one end of the inner snap-fit portion away from the bottom of the groove.
[0014] This application also provides a battery pack comprising the individual battery cells of this application.
[0015] The single cell and battery pack provided in this application embodiment include an inner tab comprising a fixed base portion and a welding extension portion. The fixed base portion includes a first end portion, a second end portion, and a folded position. The first end portion is connected to the first side surface of the electrode core and disposed adjacent to the top surface of the electrode core. The second end portion is connected to the welding extension portion, which extends along the thickness direction of the electrode core. A snap-fit groove is formed between the welding extension portion and the first side surface of the electrode core. The outer tab extends into the snap-fit groove and is welded to the inner tab. This avoids the welding of the inner tab and the outer tab occupying too much space in the single cell, which is beneficial to increasing the energy density of the single cell.
[0016] In this embodiment, the inner tab is located between the first end and the second end. A fifth gap is provided between the vertex of the inner tab in the thickness direction of the electrode core and the top surface of the electrode core. The ratio of the fifth gap to the thickness of the electrode core is 0.026-0.11. This can prevent the top of the welding snap part of the outer tab from contacting the fixed base part, prevent the burrs of the welding snap part of the outer tab from cutting the diaphragm and electrode sheet of the electrode core, and prevent the electrode core from short-circuiting. Attached Figure Description
[0017] 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 accompanying 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.
[0018] Figure 1 This is a schematic diagram of the structure of a single cell in the prior art;
[0019] Figure 2 This is a schematic diagram of the overall structure of a single battery cell provided in Embodiment 1 of this application;
[0020] Figure 3 This is a schematic diagram of the structure of the electrode core and inner electrode tab provided in Embodiment 1 of this application;
[0021] Figure 4 This is a schematic diagram of the structure of the outer electrode and the electrode insulation part provided in Embodiment 1 of this application;
[0022] Figure 5 A partial structural cross-section of a single cell provided in Embodiment 1 of this application. Figure 1 ;
[0023] Figure 6 A partial structural cross-section of a single cell provided in Embodiment 1 of this application. Figure 2 ;
[0024] Figure 7 This is a partial structural cross-sectional view of a single battery cell provided in Embodiment 2 of this application;
[0025] Figure 8 This is a partial structural cross-sectional view of a single battery cell provided in Embodiment 3 of this application.
[0026] The markings in the diagram are as follows:
[0027] 90. Single cell; 91. Electrode core; 92. Inner tab; 93. Outer tab; 94. Aluminum-plastic film casing;
[0028] 1. Inner tab; 2. Outer tab; 3. Electrode core; 4. Solder mark; 5. Insulating component;
[0029] 11. Fixed base portion; 12. Welded extension portion; 111. First end portion; 112. Second end portion; 113. Closed position; 21. Welded snap-fit portion; 22. Current lead-out portion; 211. Inner snap-fit portion; 212. Outer snap-fit portion; 213. Connecting portion;
[0030] 31. First side surface; 32. Top surface. Detailed Implementation
[0031] The preferred embodiments of this application are described in detail below with reference to the accompanying drawings to fully introduce the technical content of this application to those skilled in the art, to demonstrate that this application can be implemented, and to make the disclosed technical content of this application clearer, so that those skilled in the art can more easily understand how to implement this application. However, this application can be embodied in many different forms of embodiments, and the protection scope of this application is not limited to the embodiments mentioned herein. The description of the embodiments below is not intended to limit the scope of this application.
[0032] The directional terms used in this application, such as "up", "down", "front", "back", "left", "right", "inside", "outside", and "side", are only for the directions shown in the accompanying drawings. The directional terms used herein are for the purpose of explaining and illustrating this application, and not for limiting the scope of protection of this application.
[0033] In the accompanying drawings, components with the same structure are indicated by the same numerical designation, and components with similar structures or functions are indicated by similar numerical designations. Furthermore, for ease of understanding and description, the dimensions and thicknesses of each component shown in the drawings are arbitrary, and this application does not limit the dimensions and thicknesses of each component.
[0034] Please see Figure 1 In the prior art, a single cell 90 includes a core 91, inner tabs 92, and outer tabs 93. The inner tabs 92 are located on both sides of the core 91 along its length. The inner tabs 92 and outer tabs 93 are fixed together by laser welding, connecting them and allowing current to be drawn out of the aluminum-plastic film casing 94. However, this structure, where the inner tabs 92 extend along the length of the core 91 and are fixed to the outer tabs 93 by laser welding, results in a relatively low overall energy density for the pouch cell.
[0035] Example 1
[0036] Please see Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6In Embodiment 1 of this application, a single cell battery is provided, which includes an inner tab 1, an outer tab 2, an electrode core 3, and an insulating component 5.
[0037] The electrode core 3 is located inside the aluminum-plastic film shell (not shown). The electrode core 3 has a first side surface in its length direction and a top surface 32 in its thickness direction. The inner electrode tab 1 is located inside the aluminum-plastic film shell (not shown). One end of the inner electrode tab 1 is connected to the electrode core 3, and the other end of the inner electrode tab 1 is connected to the outer electrode tab 2. A portion of the outer electrode tab 2 is located inside the aluminum-plastic film shell (not shown) and welded to the inner electrode tab 1, while the other portion of the outer electrode tab 2 extends outside the aluminum-plastic film shell (not shown).
[0038] The inner tab 1 includes a fixed base portion 11 and a welding extension portion 12. The fixed base portion 11 is conical or wedge-shaped, enabling greater structural stability. The fixed base portion 11 includes a first end portion 111, a second end portion 112, and a retracted position 113. The first end portion 111 is connected to the first side surface 31 of the electrode core 3 and is disposed adjacent to the top surface 32 of the electrode core 3. The second end portion 112 is connected to the welding extension portion 12. The retracted position 113 is located between the first end portion 111 and the second end portion 112. It is worth noting that the retracted position 113 refers to the position where the multiple inner tabs are retracted by welding.
[0039] The welding extension 12 extends along the thickness direction of the electrode core 3, and a snap-fit groove 13 is formed between the welding extension 12 and the first side surface 31 of the electrode core 3. The outer tab 2 extends into the snap-fit groove 13 and is connected to the welding extension 12. This can avoid the welding of the inner tab 1 and the outer tab 2 occupying too much space of the single cell, which is beneficial to increasing the energy density of the single cell.
[0040] In this embodiment, a fifth spacing A is provided between the vertex of the retracted position 113 in the thickness direction of the electrode core 3 and the top surface 32 of the electrode core 3. The ratio of the fifth spacing A to the thickness B of the electrode core 3 is 0.026-0.11. Specifically, the fifth spacing A is 0.3mm-0.6mm, and the thickness B of the electrode core 3 is 5.5mm-11.5mm. In this embodiment, the ratio of the fifth spacing A to the thickness B of the electrode core 3 is 0.05. Specifically, the fifth spacing A is 0.4mm, and the thickness B of the electrode core 3 is 8mm. This avoids the top of the welding latch 21 of the outer electrode tab 2 from contacting the fixed base 11, prevents the burrs of the welding latch 21 of the outer electrode tab 2 from cutting the diaphragm and electrode sheet of the electrode core 3, and avoids short circuits in the electrode core 3.
[0041] Table 1. Parameters and test results for Examples 1 to 11
[0042]
[0043] As shown in Table 1, in Examples 8 to 11, the ratio A / B of the fifth spacing A to the thickness B of the electrode core 3 exceeds the parameter range of this application. Specifically, in Example 8, the fifth spacing A is too small, and the ratio of the fifth spacing A to the thickness B of the electrode core 3 is too small. This causes the outermost layer of the root of the inner electrode ear 1 to easily extend beyond the upper surface of the electrode core 3 after the inner electrode ear 1 is bent and welded during CT inspection, reaching the middle between the electrode core 3 and the aluminum-plastic film shell. This increases the risk of damage to the inner electrode ear 1 when the electrode core 3 is subjected to external pressure during use. In Example 9, the fifth spacing A is too large, and the ratio of the fifth spacing A to the thickness B of the electrode core 3 is too large. This results in a smaller first spacing E value between the top of the welding snap part 21 in the thickness direction of the electrode core 3 and the bottom of the snap groove 13. This increases the risk of the inner electrode ear 1 being cut by the outer electrode ear 2. In Example 10, the thickness B of the core 3 is too large, and the ratio of the fifth spacing A to the thickness B of the core 3 is too small. CT scans show that after the inner tab 1 is bent and welded, the outermost layer of the root of the inner tab 1 easily extends beyond the upper surface of the core 3, reaching the middle between the core 3 and the aluminum-plastic film shell. This increases the risk of damage to the inner tab 1 when the core 3 is subjected to external pressure during use. In Example 11, the thickness B of the core 3 is too small, and the ratio of the fifth spacing A to the thickness B of the core 3 is too large. This results in a smaller first spacing E between the top of the welded snap-fit part 21 in the thickness direction of the core 3 and the bottom of the snap-fit groove 13, increasing the risk of the inner tab 1 being cut by the outer tab 2.
[0044] As can be seen from the data in Table 1, in Examples 1 to 7, the fifth spacing A, the thickness B of the pole core 3, and the ratio of the fifth spacing A to the thickness B of the pole core 3 do not exceed the parameter range of this application, and the internal structure of the pole core 3 after CT inspection is normal.
[0045] It is important to note that CT scan refers to computed tomography (CT) scan. This is an imaging method that uses a combination of X-rays and computer technology to obtain three-dimensional images of the interior of an object.
[0046] The outer electrode 2 includes a welded snap-fit part 21 and a current lead-out part 22 connected together. The material of the outer electrode 2 can be flat or 90° bent. If the outer electrode 2 is flat, it is welded to the inner electrode 1 and then bent to a 90° bent structure using a jig to form the welded snap-fit part 21 and the current lead-out part 22. If the material of the outer electrode 2 is 90° bent, the welded snap-fit part 21 can be directly welded to the inner electrode 1.
[0047] In this embodiment, the welding snap-fit portion 21 extends at least partially into the snap-fit groove 13 and connects with the welding extension portion 12. The welding snap-fit portion 21 extends along the thickness direction of the electrode core 3. In this embodiment, the welding snap-fit portion 21 and the welding extension portion 12 are welded using laser welding or ultrasonic welding. The welding snap-fit portion 21 and the welding extension portion 12 form a weld mark 4, which is located in the middle of the welding extension portion 12. The width w of the weld mark 4 is 1.0mm-1.5mm, thereby ensuring the strength and stability of the welded joint between the welding snap-fit portion 21 and the welding extension portion 12, avoiding weak welding due to an excessively narrow weld mark 4 or material waste due to an excessively wide weld mark 4. In this embodiment, the width w of the weld mark 4 is preferably 1.2mm, and the weld mark 4 is centrally located.
[0048] In this embodiment, a third gap t is provided between the top of the weld mark 4 and the top of the welded snap-fit portion 21. The third gap t is 0.7mm-1.0mm, which helps to evenly distribute the thermal stress at the weld mark 4, reduce the risk of cracking at the weld mark 4, promote the cooling efficiency at the weld mark 4, reduce welding deformation, and reduce defects such as porosity and slag inclusions that may occur during the welding process, thereby improving the reliability of the welding. In this embodiment, the third gap t is 0.8mm.
[0049] In this embodiment, a fourth spacing m is provided between the bottom of the weld mark 4 and the bottom of the weld extension 12. The fourth spacing m is 0.7mm-1.0mm, which helps to evenly distribute the thermal stress at the weld mark 4, reduce the risk of cracking at the weld mark 4, promote the cooling efficiency at the weld mark 4, reduce welding deformation, and reduce defects such as porosity and slag inclusions that may occur during the welding process, thereby improving the reliability of the welding. In this embodiment, the fourth spacing m is 0.75mm.
[0050] When the welding latching part 21 extends into the latching groove 13, a first gap E is provided between the top of the welding latching part 21 in the thickness direction of the electrode core 3 and the bottom of the latching groove 13. The first gap E is between 1mm and 1.5mm. This can prevent the burrs of the welding latching part 21 of the outer electrode tab 2 from cutting the separator and electrode sheet of the electrode core 3 due to the first gap E being too small, thus avoiding short circuit of the electrode core 3. It can also prevent the thickness of the single cell from increasing due to the first gap E being too large.
[0051] The current lead-out portion 22 is located outside the snap-fit groove 13 and extends along the length direction of the pole core 3.
[0052] The single cell also includes an insulating component 5. The insulating component 5 is arranged around the outer periphery of the outer electrode tab 2, specifically, the insulating component 5 is arranged around the outer periphery of the current lead-out portion 22. When the thickness of the electrode core 3 is 6.5mm or more, the bottom of the insulating component 5 and the bottom of the electrode core 3 have a second distance F, the second distance F being B-6.5, in which case the bottom of the insulating component 5 is higher than the bottom of the electrode core 3; when the thickness of the electrode core 3 is less than 6.5mm, the bottom of the insulating component 5 is flush with the bottom of the electrode core 3.
[0053] Table 2 Comparison of the space occupied by the welding points of the inner and outer tabs of the electrode core.
[0054]
[0055] Please refer to Table 2. In this embodiment of the application, the welding extension 12 extends along the thickness direction of the electrode core 3. A snap-fit groove 13 is formed between the welding extension 12 and the first side surface 31 of the electrode core 3. The outer electrode tab 2 extends into the snap-fit groove 13 and is connected to the welding extension 12. This can avoid the welding of the inner electrode tab 1 and the outer electrode tab 2 occupying too much space of the single cell, which is beneficial to increasing the energy density of the single cell.
[0056] Example 2
[0057] Please see Figure 7 Embodiment 2 of this application provides a single-cell battery that includes most of the technical features of Embodiment 1, with the difference being the structure of the welding snap-fit portion 21. The welding snap-fit portion 21 includes an inner snap-fit portion 211, an outer snap-fit portion 212, and a connecting portion 213. Both the inner snap-fit portion 211 and the outer snap-fit portion 212 extend along the thickness direction of the electrode core 3, and the connecting portion 213 connects the inner snap-fit portion 211 and the outer snap-fit portion 212.
[0058] Please see Figure 7 In this embodiment, the inner snap-fit portion 211, the outer snap-fit portion 212, and the connecting portion 213 are all located within the snap-fit groove 13. The connecting portion 213 is connected to one end of the inner snap-fit portion 211 near the bottom of the snap-fit groove 13. The surface of the connecting portion 213 near the bottom of the snap-fit groove 13 is curved, meaning that the welding snap-fit portion 21 in this embodiment is inverted U-shaped. By making the surface of the connecting portion 213 near the bottom of the snap-fit groove 13 curved, the burrs of the welding snap-fit portion 21 of the outer electrode tab 2 are prevented from cutting the diaphragm and electrode sheet of the electrode core 3, thus preventing a short circuit in the electrode core 3.
[0059] In this embodiment, the welding extension 12 extends along the thickness direction of the electrode core 3, and a snap-fit groove 13 is formed between the welding extension 12 and the first side surface 31 of the electrode core 3. The outer tab 2 extends into the snap-fit groove 13 and is connected to the welding extension 12. This avoids the welding of the inner tab 1 and the outer tab 2 occupying too much space of the single cell, which is beneficial to increasing the energy density of the single cell.
[0060] Example 3
[0061] Please see Figure 8 Embodiment 3 of this application provides a single-cell battery that includes most of the technical features of Embodiment 1, with the difference being the structure of the welding snap-fit portion 21. The welding snap-fit portion 21 includes an inner snap-fit portion 211, an outer snap-fit portion 212, and a connecting portion 213. Both the inner snap-fit portion 211 and the outer snap-fit portion 212 extend along the thickness direction of the electrode core 3, and the connecting portion 213 connects the inner snap-fit portion 211 and the outer snap-fit portion 212.
[0062] Please see Figure 8 In this embodiment, the welding extension 12 is located between the inner snap-fit portion 211 and the outer snap-fit portion 212. The inner snap-fit portion 211 is located inside the snap-fit groove 13, and the connecting portion 213 is located outside the snap-fit groove 13 and connected to the end of the inner snap-fit portion 211 away from the bottom of the snap-fit groove 13. That is, the welding snap-fit portion 21 is U-shaped, thereby improving the connection stability between the welding extension 12 and the welding snap-fit portion 21 by welding the welding extension 12 between the inner snap-fit portion 211 and the outer snap-fit portion 212.
[0063] In addition, to facilitate welding of the welding extension 12 and the welding snap-fit 21, welding through holes can be provided on the outer snap-fit 212 and the welding extension 12. During welding, the welding rod passes through the welding through hole to weld the welding extension 12 to the inner snap-fit 211. Alternatively, the welding rod can pass through the welding through hole to weld the welding extension 12, the outer snap-fit 212 and the inner snap-fit 211 together.
[0064] In this embodiment, the welding extension 12 extends along the thickness direction of the electrode core 3, and a snap-fit groove 13 is formed between the welding extension 12 and the first side surface 31 of the electrode core 3. The outer tab 2 extends into the snap-fit groove 13 and is connected to the welding extension 12. This avoids the welding of the inner tab 1 and the outer tab 2 occupying too much space of the single cell, which is beneficial to increasing the energy density of the single cell.
[0065] Example 4
[0066] In embodiment 4 of this application, a battery pack is also provided, which includes the single battery cell described above. The single battery cell and battery pack provided in this application embodiment extend along the thickness direction of the electrode core 3 via a welding extension 12. A snap-fit groove 13 is formed between the welding extension 12 and the first side surface 31 of the electrode core 3. The outer electrode tab 2 extends into the snap-fit groove 13 and is connected to the welding extension 12. This avoids the welding of the inner electrode tab 1 and the outer electrode tab 2 occupying too much space in the single battery cell, which is beneficial to increasing the energy density of the single battery cell.
[0067] 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.
[0068] The above provides a detailed description of a single battery cell and a battery pack provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of this application. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A single-cell battery, characterized in that, It includes an inner electrode and an outer electrode, one end of the inner electrode is connected to the electrode core, and the other end of the inner electrode is connected to the outer electrode; The electrode core has a first side surface in its length direction and a top surface in its thickness direction. The inner electrode lug includes a fixed base portion and a welding extension portion. The fixed base portion includes a first end portion, a second end portion, and a closing position. The first end portion is connected to the first side surface of the electrode core and is disposed adjacent to the top surface of the electrode core. The second end portion is connected to the welding extension portion. The closing position is located between the first end portion and the second end portion. A fifth spacing is provided between the vertex of the closing position in the thickness direction of the electrode core and the top surface of the electrode core. The fifth spacing is 0.3mm-0.6mm. The thickness of the electrode core is 5.5mm-11.5mm. The ratio of the fifth spacing to the thickness of the electrode core is 0.026-0.
11. The welding extension portion extends along the thickness direction of the electrode core. A snap-fit groove is formed between the welding extension portion and the first side surface of the electrode core. The outer electrode lug extends into the snap-fit groove and is connected to the welding extension portion. The outer electrode lug includes a connected welding snap-fit part and a current lead-out part. The welding snap-fit part extends at least partially into the snap-fit groove and is connected to the welding extension part. The current lead-out part is located outside the snap-fit groove. The welding snap-fit part and the welding extension part are welded to form a weld mark. The width of the weld mark is 1.0mm-1.5mm. There is a third gap between the top of the solder mark and the top of the welding snap-fit portion, the third gap being 0.7mm-1.0mm; There is a fourth gap between the bottom of the solder mark and the bottom of the solder extension, the fourth gap being 0.7mm-1.0mm; When the welding snap-fit part extends into the snap-fit groove, a first gap is provided between the top of the welding snap-fit part in the thickness direction of the pole core and the bottom of the snap-fit groove, and the first gap is 1mm-1.5mm. The single cell also includes an insulating component, which is arranged around the outer periphery of the current lead-out portion. When the thickness of the electrode core is greater than 6.5 mm, the bottom of the insulating component is higher than the bottom of the electrode core, and the bottom of the insulating component and the bottom of the electrode core have a second distance, which is the difference between the thickness of the electrode core and 6.5 mm. When the thickness of the electrode core is less than 6.5 mm, the bottom of the insulating component is flush with the bottom of the electrode core.
2. The single-cell battery as described in claim 1, characterized in that, The welding snap-fit portion extends along the thickness direction of the electrode core, and the current lead-out portion extends along the length direction of the electrode core.
3. The single-cell battery as described in claim 1, characterized in that, The welding method between the welding snap-fit portion and the welding extension portion is laser welding or ultrasonic welding, and the weld mark is located in the middle of the welding extension portion.
4. The single-cell battery as described in claim 1, characterized in that, The welding snap-fit portion includes an inner snap-fit portion, an outer snap-fit portion, and a connecting portion. The inner snap-fit portion and the outer snap-fit portion both extend along the thickness direction of the electrode core, and the connecting portion connects the inner snap-fit portion and the outer snap-fit portion.
5. The single-cell battery as described in claim 4, characterized in that, The inner snap-fit part, the outer snap-fit part, and the connecting part are all located within the snap-fit groove. The connecting part is connected to one end of the inner snap-fit part near the bottom of the snap-fit groove, and the surface of the connecting part on the side near the bottom of the snap-fit groove is curved.
6. The single-cell battery as described in claim 4, characterized in that, The welding extension is located between the inner snap-fit portion and the outer snap-fit portion. The inner snap-fit portion is located inside the snap-fit groove, and the connecting portion is located outside the snap-fit groove and connected to one end of the inner snap-fit portion away from the bottom of the snap-fit groove.
7. A battery pack, characterized in that, The single-cell battery includes any one of claims 1-6.