Lithium composite negative electrode with tab and lithium battery comprising lithium composite negative electrode
By depositing a metal layer on the substrate layer of the lithium composite negative electrode to form a current collecting lead-out section, the complex problems of lithium battery ears in the prior art are solved, and the design of the ears with its own ears is realized, the production process is simplified and the product quality is improved.
Patent Information
- Application Number
- CN202420287567.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-07
- Publication Date
- 2025-03-18
- Estimated Expiration
- 2034-02-07
AI Technical Summary
In existing lithium batteries, after carbonaceous film or other conductive film materials are combined with metal lithium negative electrodes, they cannot be used directly as electrode ears, and the electrode ears of metal foil need to be introduced, and this process is complicated and inconvenient for large-scale production.
A lithium composite negative electrode with its own electrode ear is designed. By depositing a metal layer on the substrate layer to form a current collecting lead-out portion. The width of the substrate layer is greater than the width of the negative electrode layer. The current collecting lead-out portion can be directly used as the electrode ear, simplifying the production process.
The lithium composite negative electrode has its own electrode design, simplifies the production process, improves production efficiency, and ensures the surface flatness of the product and the uniformity of the overall thickness.
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Figure CN222637304U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electrochemical energy storage, in particular to a lithium composite negative electrode for a lithium battery. Background Art
[0002] As society's requirements for the energy density of lithium-ion batteries are getting higher and higher, the current research direction is turning to negative electrode materials with higher specific capacity. Metallic lithium is considered to be the best negative electrode material due to its capacity of 3860mAh / g and low potential of -3.04V. In addition, to increase the energy density of the battery, it is necessary to reduce the proportion of inactive substances. For the current collector, although the weight of the current collector copper foil can be reduced by continuously thinning the thickness of the copper current collector, the density of metallic copper is 8.96g / cm 3 , the thinnest 4um thick copper foil (4um thick copper foil is easy to break and cannot be produced continuously when coated with lithium) is still equivalent to 67um thick lithium metal. Currently, carbon film materials with certain conductivity or other flexible conductive film materials are being developed to replace the current collector copper foil. The density of carbon film materials is 1g / cm 3 It can replace the traditional current collector very well. However, the problem is that after the relevant film materials are composited with metal lithium negative electrode, carbon film materials or other conductive film materials cannot be used directly as tabs. The tabs of metal foil materials need to be led out for welding. How to lead out the tabs simply and quickly requires special design. Utility Model Content
[0003] In view of the above problems, the utility model provides a lithium composite negative electrode with a self-contained tab.
[0004] The utility model adopts the following technical solutions:
[0005] A lithium composite negative electrode with a built-in tab comprises: two negative electrode layers, an upper layer and a lower layer, and a substrate layer sandwiched between the two negative electrode layers. The width of the substrate layer is greater than that of the negative electrode layer. One end of the substrate layer is aligned with the negative electrode layer in the width direction, and the other end has a current collecting and leading portion exposing the negative electrode layer, and the current collecting and leading portion is a metal deposition layer.
[0006] In certain embodiments, the metal deposition layer is formed on the entire surface of the substrate layer or on one side edge region of the substrate layer.
[0007] In certain embodiments, the width of the current collecting and drawing portion is 10-30 mm.
[0008] In certain embodiments, the current collecting lead includes at least one metal selected from the group consisting of copper, nickel, tin, silver, and gold.
[0009] In certain embodiments, the thickness of the metal deposition layer is 1-10 um, preferably 1-5 um.
[0010] In some embodiments, the current collecting lead-out portion may be directly die-cut into a certain area of the tab for use, for example, the tab area may be 8 mm wide by 10 mm long, 10 mm wide by 15 mm long, 15 mm wide by 15 mm long, and so on.
[0011] In certain embodiments, the negative electrode layer is a metallic lithium layer or a lithium alloy layer.
[0012] In some embodiments, the substrate layer is a conductive film material or a non-conductive film material; for a conductive film material or a non-conductive film material, a current collecting lead-out portion can be formed by depositing a metal layer in an edge area of the film material, or by depositing a metal layer on the entire surface area of the film material.
[0013] For example, a carbon nanotube film is selected as the substrate layer. The width of the carbon nanotube film is 200 mm and the length is 500 meters. Since the carbon nanotube film itself is conductive, metal layers can be deposited on the upper and lower surfaces of the edge area (10 mm wide) on one side of the carbon nanotube film. The area where the metal is deposited is die-cut into a certain size and used directly as the tab.
[0014] For example, non-woven fabric is selected as the substrate layer. The width of the non-woven fabric is 150 mm and the length is 500 meters. Since the non-woven fabric itself is not conductive, it is possible to deposit metal layers on both the upper and lower surfaces of the entire non-woven fabric, and the area not covered by metallic lithium can be directly used as the electrode ear.
[0015] In some embodiments, the thickness of the negative electrode layer is 1-100 um and the width is 50-1400 mm;
[0016] In certain embodiments, the thickness of the substrate layer is 5-50 um.
[0017] In certain embodiments, the width of the substrate layer is greater than the width of the negative electrode layer.
[0018] In certain embodiments, the lithium composite negative electrode is a continuous web having a length of 1-2000 m.
[0019] In certain embodiments, the metal deposition layer (current collecting and drawing portion) is spaced apart and distributed on the other end of the substrate layer, and the metal deposition layer (current collecting and drawing portion) can be directly used as a tab without die-cutting.
[0020] The utility model also provides a lithium battery, which comprises the lithium composite negative electrode with a self-contained pole ear.
[0021] The utility model has at least one of the following advantages:
[0022] (1) The lithium composite negative electrode with a built-in tab of the utility model has a base material layer with a conductive metal layer, and the tab can be directly led out for use without the need for additional tabs.
[0023] (2) The lithium composite negative electrode with its own tabs of the present invention has a flat surface and good overall thickness uniformity because the width of the substrate layer is greater than the width of the negative electrode layer and the current collecting lead-out area is not covered with the negative electrode layer.
[0024] (3) The production process of lithium composite negative electrodes with built-in tabs is simple and can be mass-produced. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 It is a structural schematic diagram of the composite negative electrode of the utility model.
[0026] Figure 2 Another schematic diagram of the structure of the composite negative electrode of the utility model.
[0027] 1- negative electrode layer, 2- substrate layer, 3- current collecting lead DETAILED DESCRIPTION
[0028] In order to make the purpose, technical solution and advantages of the utility model more clear, the specific implementation of the utility model is described in detail below with reference to the accompanying drawings. It should be understood that the technical features involved in each implementation described below can be combined with each other as long as they do not conflict with each other.
[0029] One aspect of the utility model provides a lithium composite negative electrode with a self-contained tab. Figure 1 A schematic diagram of the structure of the composite negative electrode of the utility model is shown, wherein the lithium composite negative electrode with a self-contained tab of the utility model comprises two negative electrode layers 1, an upper negative electrode layer 1, and a substrate layer 2 sandwiched between the two negative electrode layers. The width of the substrate layer is greater than the width of the negative electrode layer, one end of the substrate layer is aligned with the negative electrode layer in the width direction, and the other end has a current collecting and leading portion 3 that exposes the negative electrode layer. The current collecting and leading portion is a metal deposition layer and can be used as a tab. Figure 2 Another schematic diagram of the structure of the composite negative electrode of the utility model is shown. Figure 1 The structure shown is different in that a metal deposition layer is formed on the entire surface of the substrate layer 2 , wherein the portion where the negative electrode layer is exposed is the current collecting lead-out portion 3 .
[0030] In the lithium composite negative electrode of the utility model, the negative electrode layer (active material) is made of metallic lithium or lithium alloy, and the film material of the substrate layer is made of carbonaceous film material, other flexible conductive film material or non-conductive film material.
[0031] According to one embodiment, a metal layer is first deposited on an edge region of the substrate layer or on the entire substrate region to form a current collecting and leading portion.
[0032] According to one embodiment, the active material can be distributed to most areas of the substrate layer (excluding the current collecting lead-out portion) through coating, pressure compounding, and vapor deposition processes, with one end of the active material aligned with the substrate layer in the width direction and the other end being smaller than the width of the negative electrode substrate layer.
[0033] According to one embodiment, the thickness of the active material metal lithium or lithium alloy (thickness of the negative electrode layer) can be 1-100 um, preferably 1-20 um; the width is 50-1400 mm, preferably 200-700 mm.
[0034] According to one embodiment, the lithium alloy is formed by a combination of metallic lithium and any one or at least two elements of Ag, Au, Sn, Si, Zn, Al, Mg, In, Ga, B, Mn, Sb, Bi, Cr, C, V, Cu, Fe or Ti.
[0035] According to one embodiment, the thickness of the substrate layer is 5-50 um, preferably 5-20 um.
[0036] According to one embodiment, the metal layer of the current collecting and leading-out portion is at least one of copper, nickel, tin, silver and gold.
[0037] According to one embodiment, the width of the current collecting and leading-out portion is 10-30 mm.
[0038] The lithium composite electrode can be prepared by the following method, which comprises:
[0039] The substrate is first cleaned with a mixture of ethanol and water, then washed with water, and dried. A metal layer is then deposited on the edge area of the substrate (conductive substrate) or the upper and lower surface areas of the entire substrate (non-conductive substrate) to obtain a substrate with a current collecting lead-out portion.
[0040] The upper and lower rolls of metallic lithium products and the middle layer of the substrate layer are unwound and pressure-compounded to obtain a lithium composite negative electrode with its own tabs.
[0041] Another aspect of the utility model provides the use of the composite negative electrode with a self-contained tab in a lithium battery.
[0042] According to one embodiment, the lithium battery comprises the above-mentioned lithium composite negative electrode, and the positive electrode material is selected from ternary nickel-cobalt-manganese material, ternary nickel-cobalt-aluminum material, lithium-rich manganese-based positive electrode material, lithium cobalt oxide, lithium iron phosphate, and sulfur-based positive electrode material.
[0043] According to one embodiment, the electrolyte of the lithium battery can be selected from a liquid electrolyte or a solid electrolyte; the liquid electrolyte can be selected from an ester or an ether; the solid electrolyte can be selected from a chloride solid electrolyte, an oxide solid electrolyte, a sulfide solid electrolyte, a polymer electrolyte or an organic-inorganic mixed electrolyte, such as a polyethylene oxide (mixed oxide, halide or sulfide powder) electrolyte.
[0044] For liquid batteries, the diaphragm is made of polypropylene (PP), polyethylene (PE) or a composite diaphragm of PP and PE, and the diaphragm can be coated with ceramic or polyvinylidene fluoride. The battery can be square, soft pack or cylindrical.
[0045] The present invention is illustrated below by way of examples. The various product structural parameters, various reaction participants and process conditions used in the following examples are all relatively typical examples. However, after a large number of experiments and verifications by the inventor of this case, other different structural parameters, other types of reaction participants and other process conditions listed above are also applicable and can also achieve the technical effects claimed in this utility model.
[0046] Example 1
[0047] A rolled conductive carbon nanotube film was selected as the substrate, the width of the substrate was 200 mm, and the length was 200 meters. The carbon nanotube film was cleaned with a mixture of ethanol and water, then washed with water, and dried in a forced air drying oven at 100°C for 12 hours for standby use. A copper layer was deposited on the edge area (width 20 mm) on one side of the substrate. The copper layer needed to be deposited on both sides of the edge area of the substrate. The thickness of the single-sided copper layer was 3 um, and a substrate with a self-contained current collecting lead-out portion was obtained.
[0048] At the same time, two rolls of lithium film (lithium with plastic film support, lithium thickness 10um, width 179mm) and the middle layer substrate with its own current collecting lead-out part are unwound, and after rolling, a lithium composite negative electrode with its own pole ear is obtained.
[0049] The size of the die-cut negative electrode sheet is 45*58mm, and the size of the tab is 8mm wide*10mm long. The corresponding die is customized, the position of the tab on the electrode sheet is determined, and the negative electrode sheet with a small tab is directly die-cut. The area of the negative electrode sheet is lithium layer + substrate layer + lithium layer, and the tab area is copper layer + substrate layer + copper layer.
[0050] Example 2
[0051] A rolled non-conductive fiber material is selected as the substrate, the width of the substrate is 150 mm, and the length is 500 meters. The fiber membrane material is cleaned with a mixture of ethanol and water, then washed with water, and dried in a blast drying oven at 100°C for 12 hours for standby use. A nickel layer is deposited on the entire area of the substrate, and a nickel layer needs to be deposited on both sides of the substrate. The thickness of the single-sided nickel layer is 2um, and a substrate with a self-contained current collecting lead-out portion is obtained.
[0052] At the same time, two rolls of lithium metal tape (lithium thickness 20um, width 135mm) and the middle layer substrate with its own current collecting lead-out part are unwound, and after rolling, a lithium composite negative electrode with its own tabs is obtained.
[0053] The size of the die-cut negative electrode sheet is 45*58mm, and the size of the tab is 7mm wide*8mm long. The corresponding die is customized, the position of the tab on the electrode sheet is determined, and the negative electrode sheet with a small tab is directly die-cut. The area of the negative electrode sheet is lithium layer + nickel layer + substrate + nickel layer + lithium layer, and the tab area is nickel layer + substrate layer + nickel layer.
[0054] Example 3: The negative electrode uses the lithium composite negative electrode prepared in Example 1, and the positive electrode uses NCM (811 nickel-cobalt-manganese ternary positive electrode), and the coating surface density is 50 mg / cm 2 The positive electrode sheet area is 43*56mm, the negative electrode sheet area is 45*58mm, and the PE material separator is used to assemble a 4-positive and 5-negative soft-pack battery. The electrolyte uses 1M LiPF6, EC (ethylene carbonate): EMC (ethyl methyl carbonate) = 3:7 (vol / vol). The negative electrode sheet, NCM ternary positive electrode sheet and separator are assembled into a soft-pack battery with the help of a stacking machine. The test voltage range is 2.8-4.35V, the charging current is 0.2C, and the discharge current is 0.5C.
[0055] Example 4: The negative electrode uses the lithium composite negative electrode prepared in Example 2, and the positive electrode uses NCM (811 nickel-cobalt-manganese ternary positive electrode), and the coating surface density is 50 mg / cm 2 The positive electrode sheet area is 43*56mm, the negative electrode sheet area is 45*58mm, and the PE material separator is used to assemble a 4-positive and 5-negative soft-pack battery. The electrolyte is 1M LiPF6, EC:EMC=3:7(vol / vol). The negative electrode sheet, NCM ternary positive electrode sheet and separator are assembled into a soft-pack battery with the help of a stacking machine. The test voltage range is 2.8-4.35V, the charging current is 0.2C, and the discharge current is 0.5C.
[0056] Comparative Example 1:
[0057] The upper and lower rolls of lithium film are unwound at the same time, the thickness of the lithium film is 10um, and the current collector copper foil (thickness 6um) in the middle position is unwound at the same time, the width of the copper foil is 200mm, and the width of the lithium film is 179mm. The unwinding speed of the copper foil and the metallic lithium film is the same. The three-layer strip is pressure-compounded to obtain a lithium composite negative electrode with copper foil tabs.
[0058] Comparative Example 2: The negative electrode used was the lithium composite negative electrode of Comparative Example 1, and the assembly of the positive electrode, separator, electrolyte and soft-pack battery was the same as that of Example 3.
[0059] Table 1 Battery specific energy comparison
[0060] Group Specific energy of battery cell (wh / kg) Number of cycles (capacity decay 80%) Example 3 426.5 118 Example 4 410.3 120 Comparative Example 2 399.7 103
[0061] The specific energy of the battery in the embodiment is improved by 2.65% and 6.7% compared with the specific energy of the battery in the comparative example.
[0062] It should be understood that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A lithium composite negative electrode with a self-contained tab, characterized in that: The lithium composite negative electrode comprises: Two negative electrode layers, upper and lower, and a substrate layer sandwiched between the two negative electrode layers; The width of the substrate layer is greater than that of the negative electrode layer, one end of the substrate layer is aligned with the negative electrode layer in the width direction, and the other end has a current collecting and leading portion exposing the negative electrode layer, and the current collecting and leading portion is a metal deposition layer.
2. The lithium composite negative electrode with a self-contained tab according to claim 1, characterized in that: The metal deposition layer is formed on the entire surface of the substrate layer or on one side edge region of the substrate layer.
3. The lithium composite negative electrode with a tab according to claim 1, characterized in that: The substrate layer is a conductive film material or a non-conductive film material.
4. The lithium composite negative electrode with a tab according to claim 1, characterized in that: The thickness of the metal deposition layer is 1-10 um.
5. The lithium composite negative electrode with a tab according to claim 1, characterized in that: The thickness of the substrate layer is 5-50 um.
6. The lithium composite negative electrode with a tab according to claim 1, characterized in that: The width of the current collecting and leading-out portion is 10-30 mm.
7. The lithium composite negative electrode with a tab according to claim 1, characterized in that: The negative electrode layer is a metal lithium layer or a lithium alloy layer, and the thickness of the negative electrode layer is 1-100 um and the width is 50-1400 mm.
8. The lithium composite negative electrode with a self-contained tab according to claim 1, characterized in that: The lithium composite negative electrode is a continuous web with a length of 1-2000 m.
9. The lithium composite negative electrode with a tab according to claim 1, characterized in that: The metal deposition layers are spaced apart on the other end of the substrate layer.
10. A lithium battery, characterized in that: The lithium battery comprises the lithium composite negative electrode with a self-contained tab according to any one of claims 1 to 9.