Battery cell and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cell and a battery pack, and the battery cell comprises a pole group, an outer pole lug and a packaging film. The pole group comprises a pole core and an inner pole lug arranged at the end part of the pole core; the outer tab comprises an electrode plate body and a welding part arranged at one end of the electrode plate body, the welding part is of a double-layer structure and comprises a first welding layer and a second welding layer, an insertion gap is formed between the first welding layer and the second welding layer, the inner tab is inserted into the insertion gap, and the first welding layer, the inner tab and the second welding layer are welded; the electrode plate body is provided with an insulating part, the distance between the welding part and the insulating part in the X direction is a, and a is larger than or equal to 0.5 mm and smaller than or equal to 1 mm; the packaging film hermetically coats the outer surface of the electrode group, the insulating part of the outer tab is fused and connected with the packaging film, and the electrode plate body is exposed out of the packaging film. According to the utility model, the inner tab can be effectively prevented from slipping off, the quality problems of foil tearing or insufficient welding and the like after the inner tab is welded are avoided, the welding strength is improved, and the product yield and the production efficiency are improved.

Description

Technical Field

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

[0002] Soft-pack lithium batteries, also known as soft-pack cells, typically refer to lithium batteries with an aluminum-plastic film-encapsulated casing. Due to their numerous advantages, such as light weight, low mold cost, high structural flexibility, high energy density, and high safety performance, they have been widely used in various fields such as electric vehicles, drones, smart homes, and power banks.

[0003] A pouch cell mainly consists of an electrode assembly, an outer tab, and a packaging film. The electrode assembly includes the electrode core and an inner tab, with the inner tab located above the outer tab and the two welded together.

[0004] However, with this technical solution, quality problems such as the inner tab detaching from the surface of the outer tab, tearing of the tab foil at the solder joint, and low welding strength are prone to occur during the welding process, resulting in a low product yield. Utility Model Content

[0005] In view of this, the present invention provides a battery cell and battery pack to solve the problems of low welding strength of inner and outer tabs and low product yield.

[0006] In a first aspect, this utility model provides a battery cell, including an electrode assembly, an outer tab, and a packaging film. The electrode assembly includes an electrode core and an inner tab disposed at one end of the electrode core; the outer tab includes an electrode body and a welding portion disposed at one end of the electrode body, the welding portion having a double-layer structure, namely a first welding layer and a second welding layer, with an insertion gap between the first welding layer and the second welding layer, the inner tab being inserted into the insertion gap, and the first welding layer, the inner tab, and the second welding layer being welded together; the electrode body has an insulating component, and the distance between the welding portion and the insulating component along the X direction is a, 0.5mm≤a≤1mm; the packaging film seals and covers the outer surface of the electrode assembly, the insulating component of the outer tab is fused to the packaging film, and the electrode body is exposed outside the packaging film.

[0007] Beneficial effects: The battery cell provided by this utility model has a double-layer structure for the outer electrode tab. An insertion gap is set between the first welding layer and the second welding layer. The inner electrode tab is inserted into the insertion gap, and then the first welding layer, the inner electrode tab, and the second welding layer are welded together. At the same time, the distance 'a' between the welding part and the insulation part of the outer electrode tab along the X direction is controlled within the range of 0.5mm to 1mm. This can meet the welding requirements with the inner electrode tab, effectively prevent the inner electrode tab from slipping off, avoid quality problems such as foil tearing or incomplete welding after the inner electrode tab is welded, improve welding strength, and improve product yield and production efficiency.

[0008] In one alternative implementation, the total length of the outer electrode tab along the X direction is L1, where 40mm ≤ L1 ≤ 60mm.

[0009] In one optional embodiment, the width of the electrode body along the Y direction is W1, where 40mm≤W1≤55mm.

[0010] In one optional embodiment, the thickness of the electrode sheet body is T1, where 0.3 mm ≤ T1 ≤ 0.4 mm.

[0011] In one alternative embodiment, the length of the welded portion along the X direction is L2, where 6mm ≤ L2 ≤ 10mm.

[0012] In one optional embodiment, the width of the welded portion along the Y direction is W2, and the width of the inner electrode lug along the Y direction is W3, where 4mm≤W2-W3≤6mm.

[0013] In one alternative embodiment, the total thickness of the welded portion is T2, where 0.45mm ≤ T2 ≤ 0.55mm.

[0014] In one optional embodiment, the overlap length L3 between the welded part and the inner electrode ear along the X direction is 3mm, the welded part and the inner electrode ear are welded to form a weld mark, the width of the weld mark along the Y direction is b, 3mm≤b≤5mm, the distance between the free end of the inner electrode ear and the weld mark along the X direction is c, the distance between the end of the outer electrode ear near the electrode group and the weld mark along the X direction is d, 5mm≤d≤7mm, and L3=b+c+d.

[0015] In one alternative embodiment, the thickness of the insulating element is T3, where 0.6 mm ≤ T3 ≤ 0.7 mm.

[0016] Secondly, this utility model also provides a battery pack, including the battery cells described in the above technical solutions.

[0017] Beneficial effects: Since the battery pack includes battery cells, it has the same effects as the battery cells, which will not be elaborated here. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a battery cell after the electrode core and outer electrode tab are assembled according to an embodiment of the present utility model.

[0020] Figure 2 This is an exploded view of the structure of a battery cell according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the structure of the outer electrode tab in a battery cell according to an embodiment of the present invention;

[0022] Figure 4 for Figure 3 A magnified view of a section at point A in the middle;

[0023] Figure 5 This is a schematic diagram of the structure of a battery cell after the electrode core and outer electrode tab are assembled according to an embodiment of the present utility model;

[0024] Figure 6 for Figure 5 A magnified view of a section at point B in the middle;

[0025] Figure 7 for Figure 5 A magnified view of a section at point C.

[0026] Explanation of reference numerals in the attached figures:

[0027] 1. Electrode assembly; 11. Electrode core; 12. Inner electrode tab; 2. Outer electrode tab; 21. Electrode sheet body; 22. Welding part; 221. First welding layer; 222. Second welding layer; 223. Insertion gap; 23. Insulating component; 24. Welding mark; 3. Packaging film. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0029] The existing pouch cell structure mainly includes a packaging film, electrode assembly, and outer tabs. The electrode assembly includes the electrode core and inner tabs, while the outer tabs include electrode plates and insulating components.

[0030] The aluminum-plastic film is punched out of the cavity to accommodate the electrode assembly using a die. After the electrode assembly is placed in the cavity, it is sealed by heat-sealing the edges of the packaging film. Simultaneously, during the sealing process, the electrode tabs are heat-sealed with the insulating components of the outer electrode tabs to achieve cell sealing. One end of the outer electrode tab is fixed to the inner electrode tab of the electrode assembly by laser welding, while the other end of the outer electrode tab extends to the outside of the packaging film to conduct current. The middle of the outer electrode tab is isolated from the packaging film by an insulating component.

[0031] In related technologies, the outer tab comprises two parts: an electrode sheet and an insulating component. The electrode sheet is a flat aluminum sheet with a thickness of 0.25mm to 0.5mm, and the insulating component is formed by injection molding. The outer tab and inner tab are fixed together by laser welding, with the inner tab positioned above the corresponding position on the electrode sheet before welding. During the welding process, this method is prone to quality problems such as the tab detaching from the electrode sheet surface, tearing of the tab foil at the weld point, and low weld strength, resulting in a low yield rate.

[0032] The following is combined Figures 1 to 7 The following describes embodiments of the present invention.

[0033] According to an embodiment of the present invention, in a first aspect, a battery cell is provided, comprising an electrode assembly 1, an outer tab 2, and a packaging film 3. The electrode assembly 1 includes an electrode core 11 and an inner tab 12 located at the end of the electrode core 11; the outer tab 2 includes an electrode body 21 and a welding portion 22 disposed at one end of the electrode body 21, the welding portion 22 having a double-layer structure, namely a first welding layer 221 and a second welding layer 222, with an insertion gap 223 between the first welding layer 221 and the second welding layer 222, the inner tab 12 being inserted into the insertion gap 223, and the first welding layer 221, the inner tab 12, and the second welding layer 222 being welded together; the electrode body 21 is provided with an insulating member 23, the distance between the welding portion 22 and the insulating member 23 along the X direction is a, 0.5mm≤a≤1mm; the packaging film 3 seals and covers the outer surface of the electrode assembly 1, the insulating member 23 of the outer tab 2 is fused to the packaging film 3, and the electrode body 21 is exposed outside the packaging film 3.

[0034] The battery cell provided by this utility model has a double-layer structure for the outer electrode 2. An insertion gap 223 is provided between the first welding layer 221 and the second welding layer 222. The inner electrode 12 is inserted into the insertion gap 223, and then the first welding layer 221, the inner electrode 12, and the second welding layer 222 are welded together. Simultaneously, the distance 'a' along the X direction between the welded part 22 and the insulating part 23 of the outer electrode 2 is controlled within the range of 0.5mm to 1mm. Figure 4 As shown, this satisfies the welding requirements of the inner tab 12, effectively prevents the inner tab 12 from slipping off, avoids quality problems such as foil tearing or incomplete welding after the inner tab 12 is welded, improves welding strength, and increases product yield and production efficiency.

[0035] In some embodiments, the total length of the outer electrode 2 along the X direction is L1, such as... Figure 3 As shown, 40mm≤L1≤60mm.

[0036] By controlling the total length L1 of the outer electrode 2 along the X direction within the range of 40mm to 60mm, it is possible to ensure that there is sufficient overlap length between the welding part 22 and the inner electrode 12 along the X direction to meet welding requirements, improve welding strength, and avoid welding quality problems. At the same time, it is possible to ensure that the length of the electrode body 21 of the outer electrode 2 exposed in the packaging film 3 along the X direction meets the welding requirements of the external circuit.

[0037] Furthermore, under the premise of satisfying the welding requirements of the inner tab 12 and the welding requirements of the outer circuit, the total length L1 of the outer tab 2 along the X direction is minimized.

[0038] In some embodiments, the width of the electrode body 21 along the Y direction is W1, such as... Figure 3 As shown, 40mm≤W1≤55mm.

[0039] By controlling the width W1 of the electrode body 21 along the Y direction within the range of 40mm to 55mm, it can be ensured that the outer tab 2 meets the overcurrent requirements of the battery cell.

[0040] Furthermore, provided that the outer tab 2 meets the overcurrent requirements of the battery cell, the width W1 of the electrode body 21 along the Y direction is minimized.

[0041] In some embodiments, the thickness of the electrode sheet body 21 is T1, such as... Figure 6 As shown, 0.3mm≤T1≤0.4mm.

[0042] In some embodiments, the length of the welded portion 22 along the X direction is L2, such as... Figure 4 As shown, 6mm≤L2≤10mm.

[0043] By controlling the length L2 of the welded part 22 in the X direction within the range of 6mm to 10mm, it is possible to ensure that there is sufficient overlap length between the welded part 22 and the inner electrode 12 in the X direction, thereby meeting the welding requirements of the welded part 22 and the inner electrode 12, ensuring welding quality, and avoiding welding quality problems such as the inner electrode 12 detaching and incomplete welding.

[0044] In some embodiments, the width of the welded portion 22 along the Y direction is W2, such as... Figure 3 As shown, the width of the inner electrode 12 along the Y direction is W3, as... Figure 7 As shown, 4mm≤W2-W3≤6mm.

[0045] The width W2 of the welded part 22 along the Y direction is greater than the width W3 of the inner electrode 12 along the Y direction, and the difference is controlled within the range of 4mm to 6mm. This ensures that the welded part 22 of the inner electrode 12 and the outer electrode 2 meets the welding requirements and improves the welding strength and welding quality.

[0046] In some embodiments, the total thickness of the welded portion 22 is T2, such as Figure 6 As shown, 0.45mm≤T2≤0.55mm.

[0047] Specifically, the total thickness of the welded part 22 is the dimension occupied by the welded part 22 in the thickness direction of the insertion gap 223 of the welded part 22.

[0048] In some embodiments, such as Figure 6 As shown, the overlap length L3 between the welded part 22 and the inner electrode ear 12 along the X direction is 24. The welded part 22 and the inner electrode ear 12 are welded to form a weld mark 24. The width of the weld mark 24 along the Y direction is b, 3mm≤b≤5mm. The distance between the free end of the inner electrode ear 12 and the weld mark 24 along the X direction is c. The distance between the end of the outer electrode ear 2 near the electrode group 1 and the weld mark 24 along the X direction is d, 5mm≤d≤7mm. L3=b+c+d.

[0049] Specifically, the free end of the inner electrode 12 is the end of the inner electrode 12 furthest from the electrode core 11. Figure 6 The middle part is the left end of the inner pole ear 12.

[0050] The outer tab 2 is located near the end of the electrode core 11. Figure 6 The middle part is manifested at the right end of the outer pole ear 2.

[0051] This setup can meet the process welding yield requirements.

[0052] In some embodiments, the thickness of the insulating element 23 is T3, such as... Figure 6 As shown, 0.6mm≤T3≤0.7mm.

[0053] This design ensures reliable heat-sealing connection between the insulating component 23 and the packaging film 3, while also reducing the molding difficulty of the insulating component 23.

[0054] In some embodiments, the insulating component 23 is insulating adhesive. The packaging film 3 is an aluminum-plastic film shell.

[0055] According to an embodiment of the present invention, in a second aspect, a battery pack is also provided, including the battery cells described in the above embodiments.

[0056] Since the battery pack includes battery cells and has the same effect as the battery cells, it will not be elaborated on here.

[0057] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery cell, characterized in that, include: An electrode assembly, the electrode assembly including an electrode core and an inner electrode tab disposed at the end of the electrode core; The outer electrode tab includes an electrode body and a welding portion disposed at one end of the electrode body. The welding portion has a double-layer structure, consisting of a first welding layer and a second welding layer. An insertion gap is provided between the first welding layer and the second welding layer. The inner electrode tab is inserted into the insertion gap. The first welding layer, the inner electrode tab, and the second welding layer are welded together. The electrode body is provided with an insulating component. The distance between the welding portion and the insulating component along the X direction is a, where 0.5mm ≤ a ≤ 1mm. A packaging film is used to seal and cover the outer surface of the electrode assembly. The insulating part of the outer electrode tab is fused to the packaging film, and the electrode sheet itself is exposed outside the packaging film.

2. The battery cell according to claim 1, characterized in that, The total length of the outer electrode ear along the X direction is L1, 40mm≤L1≤60mm.

3. The battery cell according to claim 1 or 2, characterized in that, The width of the electrode sheet body along the Y direction is W1, 40mm≤W1≤55mm.

4. The battery cell according to claim 1 or 2, characterized in that, The thickness of the electrode sheet body along the Z direction is T1, where 0.3mm≤T1≤0.4mm.

5. The battery cell according to claim 1 or 2, characterized in that, The length of the welded part along the X direction is L2, where 6mm ≤ L2 ≤ 10mm.

6. The battery cell according to claim 1 or 2, characterized in that, The width of the welded part along the Y direction is W2, and the width of the inner electrode lug along the Y direction is W3, where 4mm ≤ W2 - W3 ≤ 6mm.

7. The battery cell according to claim 1 or 2, characterized in that, The total thickness of the welded part along the Z direction is T2, 0.45mm≤T2≤0.55mm.

8. The battery cell according to claim 1 or 2, characterized in that, The overlap length L3 between the welded part and the inner electrode lug along the X direction, the welded part and the inner electrode lug forming a weld mark, the width of the weld mark along the Y direction is b, 3mm≤b≤5mm, the distance between the free end of the inner electrode lug and the weld mark along the X direction is c, the distance between the end of the outer electrode lug near the electrode group and the weld mark along the X direction is d, 5mm≤d≤7mm, L3=b+c+d.

9. The battery cell according to claim 1 or 2, characterized in that, The thickness of the insulating component along the Z direction is T3, where 0.6mm ≤ T3 ≤ 0.7mm.

10. A battery pack, characterized in that, The battery cell includes any one of claims 1 to 9.

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