Composite current collector structure for improving welding reliability of lithium battery, laminated body and lithium battery with high welding reliability

Abstract

The utility model discloses a composite current collector structure for improving the welding reliability of a lithium battery. The composite current collector structure comprises a supporting foil layer and a dressing layer laid on the side surface of the supporting foil layer, the bearing foil layer comprises a welding supporting section and a dressing bearing section; the dressing bearing section is connected with a tab of an electrode through the welding supporting section; dressing layers are laid on the two sides of the dressing bearing section; the thickness of the bearing foil layer at the welding supporting section is D1, and the thickness of the bearing foil layer at the dressing bearing section is D2, D1gt; d2. The thickness of the supporting foil layer on the welding supporting section is larger than that of the supporting foil layer on the dressing bearing section, so that the welding area of the supporting foil layer and the electrode tab is enlarged, the welding strength is improved, meanwhile, the position, making contact with electrolyte, of the supporting foil layer is kept to be an ultrathin current collector, the energy density is not affected, and the effect of considering the energy density and the welding strength is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium batteries, in particular to a composite current collector structure, a laminated body and a lithium battery with high welding reliability for improving the welding reliability of lithium batteries. Background Art

[0002] With the continuous increase in the market requirements for battery power and energy density, in order to meet the market demand, each manufacturer has used ultra-thin current collectors to reduce the thickness and weight of the substrate. However, the strength of the ultra-thin current collector is insufficient. During welding, due to the height difference at the tab position, the root part is stressed and is prone to fracture, which affects the production efficiency and yield of this process section. Flowing into the next process, not only the capacity cannot meet the customer's requirements, but also there are potential safety risks. Currently, the ultra-thin current collector has a low tensile strength and is prone to welding fracture during welding.

[0003] Therefore, it is necessary to develop a current collector that does not affect welding and does not affect energy density. Summary of the Utility Model

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the utility model is to provide a composite current collector structure, a laminated body and a lithium battery with high welding reliability for improving the welding reliability of lithium batteries.

[0005] The technical solution adopted by the utility model to solve its technical problems is:

[0006] A composite current collector structure for improving the welding reliability of lithium batteries, comprising: a supporting foil layer and a dressing layer laid on the side of the supporting foil layer; the supporting foil layer includes a welding support section and a dressing bearing section; the dressing bearing section is connected to the tab of the electrode through the welding support section; dressing layers are laid on both sides of the dressing bearing section; the thickness of the supporting foil layer in the welding support section is D1, and the thickness of the supporting foil layer in the dressing bearing section is D2, and D1 > D2.

[0007] By adopting the above technical solution, the thickness of the supporting foil layer in the welding support section is greater than the thickness of the supporting foil layer in the dressing bearing section, which increases the welding area between the supporting foil layer and the electrode tab, increases the welding strength, and at the same time keeps the ultra-thin current collector at the position in contact with the electrolyte, without affecting the energy density, achieving the effect of taking into account both energy density and welding strength.

[0008] As an improved solution, the thickness of the dressing layer is D3, and D3:D2 > 1:4.

[0009] By adopting the above technical solution, the ratio of the thickness of the dressing layer to the thickness of the supporting foil layer in the dressing bearing section is maintained within a certain range, taking into account both the thickness of the dressing and the strength of the supporting foil layer.

[0010] As an improved solution, D1 = D2 + D3.

[0011] By adopting the above technical solution, the thickness of the entire composite current collector is consistent, which is conducive to mutual stacking.

[0012] As an improved solution, D1 > D2 + D3, and a plurality of mutually parallel dressing bearing segments extend in the same direction from the welding support segment.

[0013] As an improved solution, the thickness of the tab is D4, and D4 ≤ D1.

[0014] By adopting the above technical solution, the thickness of the tab is not greater than the thickness of the supporting foil layer at the welding support segment, ensuring that when the tab is welded to the supporting foil layer, the supporting foil layer is in full contact with one side of the tab or even surrounds one end, further improving the welding strength and making it not easy to break.

[0015] As an improved solution, the material of the supporting foil layer includes at least one of a metal conductive material or a carbon-based conductive material; the metal conductive material includes at least one of aluminum, copper, nickel, titanium, silver, nickel-copper alloy or aluminum-zirconium alloy; the carbon-based conductive material includes at least one of graphite, acetylene black, graphene or carbon nanotubes.

[0016] A stacked body includes a positive electrode stacked group and a negative electrode stacked group. Each of the positive electrode stacked group and the negative electrode stacked group contains a plurality of the above-mentioned composite current collector structures; the plurality of composite current collector structures are arranged in parallel with each other, and a plurality of welding support segments of the positive electrode stacked group are arranged in parallel with each other; a plurality of welding support segments of the negative electrode stacked group are arranged in parallel with each other; the dressing bearing segments of the positive electrode stacked group and the negative electrode stacked group are stacked alternately.

[0017] As an improved solution, the total thickness of a plurality of welding support segments of the positive electrode stacked group, that is, the total thickness of the positive electrode welding end, is D5; the total thickness of a plurality of welding support segments of the negative electrode stacked group, that is, the total thickness of the negative electrode welding end, is D6; the total thickness of the dressing bearing segments of the positive electrode stacked group and the negative electrode stacked group is D7; D5 = D6 = D7.

[0018] By adopting the above technical solution, after a plurality of composite current collectors form a stacked body according to the positive and negative electrodes, the thicknesses of the positive electrode pole handle and the negative electrode pole handle formed by overlapping a plurality of welding support segments are equal to the total thickness of the stacked body formed by overlapping the dressing bearing segments of the positive electrode stacked group and the negative electrode stacked group, resulting in relatively thick positive and negative electrode pole handles, which are on the same plane as the stacked body. When welding, the pole handles are flat and will not be affected by the welding strength. The probability of welding breakage is greatly reduced, and the rejection rate and scrap rate are significantly reduced.

[0019] A lithium battery with high welding reliability includes a battery package body. The battery package body contains the above-mentioned laminated body and electrolyte, and also includes a battery positive electrode and a battery negative electrode. The battery positive electrode is electrically connected to the welding support section of the positive electrode laminated group; the battery negative electrode is electrically connected to the welding support section of the negative electrode laminated group.

[0020] As an improved scheme, the thickness of the battery positive electrode is D8, the thickness of the battery negative electrode is D9, D8 = D5, D9 = D6.

[0021] Compared with the prior art, the beneficial effects of the present utility model are as follows:

[0022] The thickness of the supporting foil layer at the welding support section is greater than the thickness of the supporting foil layer at the dressing bearing section. This increases the welding area between the supporting foil layer and the electrode tab, enhances the welding strength, and at the same time maintains an ultra-thin current collector at the position in contact with the electrolyte, without affecting the energy density, achieving the effect of balancing energy density and welding strength. Description of the Drawings

[0023] Figure 1 It is a side-sectional structure diagram of a composite current collector structure for improving the welding reliability of a lithium battery according to the present utility model.

[0024] Figure 2 It is a side-sectional structure diagram of another scheme of a composite current collector structure for improving the welding reliability of a lithium battery according to the present utility model.

[0025] Figure 3 It is a structure schematic diagram of a composite current collector laminated into a laminated body state for improving the welding reliability of a lithium battery according to the present utility model.

[0026] Among them, 1: supporting foil layer; 2: dressing layer; 3: welding support section; 4: dressing bearing section; 5: positive electrode laminated group; 6: negative electrode laminated group; 7: positive electrode welding end; 8: negative electrode welding end. Specific Embodiments

[0027] Now, the present utility model will be further described in conjunction with the drawings and embodiments:

[0028] The following will further describe the present utility model in conjunction with specific embodiments. It should be understood that the following embodiments are only used to illustrate the present utility model and not to limit the scope of the present utility model.

[0029] It should be noted that when a component / part is referred to as being "disposed on" another component / part, it can be directly disposed on the other component / part or there may also be an intermediate component / part. When a component / part is referred to as being "connected / coupled" to another component / part, it can be directly connected / coupled to the other component / part or there may be an intermediate component / part present at the same time. The term "connected / coupled" as used herein may include electrical and / or mechanical physical connections / couplings. The term "comprising / including" as used herein means the presence of a feature, step or component / part, but does not exclude the presence or addition of one or more other features, steps or component / parts. The term "and / or" as used herein includes any and all combinations of one or more of the related listed items.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit this application. Additionally, in the description of this application, the terms "first", "second", etc. are used only for descriptive purposes and to distinguish similar objects, and there is no sequence between them, nor can they be construed as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0031] The features described herein can be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many possible ways of implementing the methods, devices, and / or systems described herein that will be apparent after understanding the disclosure of this application.

[0032] As used herein, the term "and / or" includes any one of the listed related items and any combination of any two or more of them.

[0033] The terms used herein are only for describing various examples and are not used to limit this disclosure. Unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. The terms "comprising", "including" and "having" enumerate the stated features, quantities, operations, components, elements and / or combinations thereof that exist, but do not exclude the existence or addition of one or more other features, quantities, operations, components, elements and / or combinations thereof.

[0034] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings, but include changes in shape that occur during manufacturing.

[0035] The features of the examples described herein may be combined in various ways that will be apparent after understanding the disclosure of the present application. In addition, although the examples described herein have various configurations, other configurations are possible as will be apparent after understanding the disclosure of the present application.

[0036] Implementation case 1:

[0037] As attached Figures 1 - 3 As shown, a composite current collector structure for improving the welding reliability of a lithium battery comprises: a supporting foil layer 1 and a dressing layer 2 laid on the side of the supporting foil layer 1; the supporting foil layer 1 comprises a welding supporting section 3 and a dressing bearing section 4; the dressing bearing section 4 is connected to the electrode tab through the welding supporting section 3; the dressing layer 2 is laid on both sides of the dressing bearing section 4; the thickness of the supporting foil layer 1 in the welding supporting section 3 is D1, and the thickness of the supporting foil layer 1 in the dressing bearing section 4 is D2, and D1>D2.

[0038] The thickness of the supporting foil layer 1 in the welding support section 3 is greater than the thickness of the supporting foil layer 1 in the dressing bearing section 4, which increases the welding area between the supporting foil layer 1 and the electrode ear and the welding strength, while also maintaining an ultra-thin current collector at the contact position with the electrolyte without affecting the energy density, thereby achieving the effect of balancing energy density and welding strength.

[0039] The thickness of the dressing layer 2 is D3, D3:D2>1:4. The thickness ratio of the dressing layer 2 to the thickness of the supporting foil layer 1 in the dressing bearing section 4 is maintained within a certain range, taking into account the thickness of the dressing and the strength of the supporting foil layer 1.

[0040] D1 = D2 + D3. The thickness of the composite current collector is consistent throughout the entire section, which is conducive to stacking.

[0041] D1>D2+D3, the welding support section 3 extends in the same direction to form a plurality of parallel dressing bearing sections 4.

[0042] The thickness of the tab is D4, where D4≯D1.

[0043] The thickness of the tab is not greater than the thickness of the supporting foil layer 1 in the welding support section 3, ensuring that when the tab and the supporting foil layer 1 are welded to each other, the supporting foil layer 1 is in full contact with one side of the tab or even surrounds one end, further improving the welding strength and preventing it from breaking easily.

[0044] The material of the supporting foil layer 1 includes at least one of a metal conductive material or a carbon-based conductive material; the metal conductive material includes at least one of aluminum, copper, nickel, titanium, silver, a nickel-copper alloy or an aluminum-zirconium alloy; the carbon-based conductive material includes at least one of graphite, acetylene black, graphene or carbon nanotubes.

[0045] A stacked body includes a positive electrode stacked group 5 and a negative electrode stacked group 6. The positive electrode stacked group 5 and the negative electrode stacked group 6 each include a plurality of the composite current collector structures as described above. The plurality of composite current collector structures are arranged in parallel with each other. The plurality of welding support segments 3 of the positive electrode stacked group 5 are arranged in parallel with each other. The plurality of welding support segments 3 of the negative electrode stacked group 6 are arranged in parallel with each other. The dressing bearing segments 4 of the positive electrode stacked group 5 and the negative electrode stacked group 6 are stacked alternately.

[0046] The total thickness of the plurality of welding support segments 3 of the positive electrode stacked group 5 is D5. The total thickness of the plurality of welding support segments 3 of the negative electrode stacked group 6 is D6. The total thickness of the dressing bearing segments 4 of the positive electrode stacked group 5 and the negative electrode stacked group 6 is D7. D5 = D6 = D7.

[0047] After a plurality of composite current collectors form a stacked body according to the positive and negative electrodes, the thicknesses of the positive electrode pole handle and the negative electrode pole handle formed by overlapping the plurality of welding support segments 3 are equal to the total thickness of the stacked body formed by overlapping the dressing bearing segments 4 of the positive electrode stacked group 5 and the negative electrode stacked group 6. As a result, the positive electrode pole handle and the negative electrode pole handle are relatively thick and are on the same plane as the stacked body. When welding, the pole handle is flat and will not be affected by the welding strength. The probability of welding breakage is greatly reduced during welding, and the rejection rate and scrap rate are significantly reduced.

[0048] A lithium battery with high welding reliability includes a battery package body. The battery package body contains the stacked body and electrolyte as described above, and also includes a battery positive electrode and a battery negative electrode. The battery positive electrode is electrically connected to the welding support segment 3 of the positive electrode stacked group 5. The battery negative electrode is electrically connected to the welding support segment 3 of the negative electrode stacked group 6.

[0049] The thickness of the battery positive electrode is D8, and the thickness of the battery negative electrode is D9. D8 = D5, D9 = D6.

[0050] In summary, after a person of ordinary skill in the art reads the documents of the present invention, various other corresponding transformation schemes made without creative mental labor according to the technical solutions and technical concepts of the present invention, in different application scenarios, all fall within the scope protected by the present invention.

Claims

1. A composite current collector structure for improving the welding reliability of lithium batteries, characterized in that, Comprising: A supporting foil layer (1) and a dressing layer (2) laid on the side of the supporting foil layer (1); the supporting foil layer (1) includes a welding support section (3) and a dressing bearing section (4); the dressing bearing section (4) is connected to the tab of the electrode through the welding support section (3); dressing layers (2) are laid on both sides of the dressing bearing section (4); the thickness of the supporting foil layer (1) at the welding support section (3) is D1, and the thickness of the supporting foil layer (1) at the dressing bearing section (4) is D2, D1 > D2.

2. The composite current collector structure for improving the welding reliability of a lithium battery according to claim 1, wherein, The thickness of the dressing layer (2) is D3, D3:D2 > 1:

4.

3. The composite current collector structure for improving the welding reliability of lithium batteries according to claim 2, wherein D1 = D2 + D3.

4. The composite current collector structure for improving the welding reliability of lithium batteries according to claim 2, characterized in that, D1 > D2 + D3, and a plurality of mutually parallel dressing bearing sections (4) extend in the same direction from the welding support section (3).

5. The composite current collector structure for improving the welding reliability of a lithium battery according to claim 1, characterized in that, The thickness of the tab is D4, D4 ≯ D1.

6. A stacked body for improving the welding reliability of a lithium battery, characterized in that, Comprising a positive electrode laminate group (5) and a negative electrode laminate group (6), the positive electrode laminate group (5) and the negative electrode laminate group (6) each include a plurality of composite current collector structures as described in any one of claims 1 - 5; the plurality of composite current collector structures are arranged in parallel with each other, and the plurality of welding support sections (3) of the positive electrode laminate group (5) are arranged in parallel with each other; the plurality of welding support sections (3) of the negative electrode laminate group (6) are arranged in parallel with each other; the dressing bearing sections (4) of the positive electrode laminate group (5) and the negative electrode laminate group (6) are stacked alternately.

7. The stacked body for improving the welding reliability of a lithium battery according to claim 6, wherein, The plurality of welding support sections (3) of the positive electrode laminate group (5) form a positive electrode welding end (7) with a total thickness of D5; the plurality of welding support sections (3) of the negative electrode laminate group (6) form a negative electrode welding end (8) with a total thickness of D6; the total thickness of the dressing bearing sections (4) of the positive electrode laminate group (5) and the negative electrode laminate group (6) is D7; D5 = D6 = D7.

8. A lithium battery with high welding reliability, characterized in that Comprising a battery package body, the battery package body contains a laminate as described in claim 7 and an electrolyte, and further includes a battery positive electrode and a battery negative electrode, the battery positive electrode is electrically connected to the welding support section (3) of the positive electrode laminate group (5); the battery negative electrode is electrically connected to the welding support section (3) of the negative electrode laminate group (6).

9. The lithium battery with high welding reliability as described in claim 8, wherein The thickness of the battery positive electrode is D8, the thickness of the battery negative electrode is D9, D8 = D5, D9 = D6.

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