A preparation method for reducing cracks in battery foil substrate

Abstract

The invention discloses a preparation method for reducing edge cracks in a battery foil substrate, comprising the following steps: raw material preparation, pouring the prepared raw materials into a smelting furnace in sequence, adding glass fiber into a mixed solution A, casting and rolling, a first pass, a first puncture, a second pass, a first trimming, a first puncture, a first annealing, a third pass, a fourth pass, a second trimming, a second annealing, a fifth pass, a sixth pass, a third trimming, slitting, and testing; packaging and warehousing. The device uses the operations of puncturing and trimming the edges of the substrate multiple times to effectively reduce the risk of cracking of the substrate during the rolling process. After the substrate is formed, it is not easy to bend or crack during rolling, has stronger chemical stability, avoids the problem of a large number of pinholes and cracks, and meets the production requirements of high-quality aluminum foil; improves the tensile strength and elongation of the substrate, which are relatively poor, so that the capacity of the battery in the substrate is expanded, the service life is extended, and the production cost of the substrate is reduced.

Description

Technical Field

[0001] The invention relates to a preparation method for reducing edge cracks of a battery foil substrate. Background Art

[0002] Currently, the commonly used existing technology in the industry is as follows: aluminum foil for power batteries is commonly used as the positive electrode current collector for lithium-ion batteries. With the advancement of battery technology, especially in the field of new energy vehicles, higher battery capacity requirements have been placed on the battery industry, and the battery industry has also placed high demands on aluminum foil for power batteries with high strength and high elongation. Domestic power battery aluminum foil, including grades such as 1235, 1100, 1060, and 8079, is relatively thick and has poor tensile strength and elongation, resulting in a smaller battery capacity and shorter service life. Producing aluminum foil for power batteries with higher tensile strength and elongation is an unresolved problem. Typically, the billet, produced by continuous casting and cold rolling of melt-cast and continuous rolling mill, undergoes only a single intermediate annealing process at a temperature above the recrystallization temperature to eliminate work hardening and internal stresses. However, the aluminum foil billet produced by this method suffers from insufficient atomic diffusion during the heat treatment and is prone to defects such as uneven microstructure and segregation. This results in low aluminum foil production yield, poor surface quality, and numerous pinholes, making it unsuitable for the production of high-quality ultra-thin aluminum foil. In order to obtain billets with good surface quality, low deformation resistance, low work hardening rate, uniform structure and less segregation, an improved heat treatment system is also particularly important.

[0003] In summary, the problems existing in the prior art are: the existing aluminum foil blanks still widely have defects such as uneven structural composition and component segregation, which lead to low aluminum foil production yield, poor surface quality, and prone to a large number of pinholes and cracks, and cannot meet the production of high-quality aluminum foil; the aluminum foil for batteries is thicker, with poor tensile strength and elongation, resulting in a smaller battery capacity, shorter service life, and higher manufacturing waste costs.

[0004] Solving technical problems is of great significance to extending the service life of batteries and improving battery collection efficiency. A preparation method for reducing cracks in battery foil substrates has emerged. Summary of the Invention

[0005] The purpose of the present invention is to solve the above deficiencies in the prior art and to provide a preparation method for reducing edge cracks in battery foil substrates.

[0006] A preparation method for reducing edge cracking of a battery foil substrate comprises the following steps:

[0007] Step 1: Prepare raw materials: weigh the raw materials of corresponding specifications according to the preparation requirements and set aside;

[0008] Step 2: Pour the prepared raw materials into the smelting furnace in sequence and stir and melt them by a stirring device. When the raw materials are completely melted, a mixed solution A is obtained;

[0009] Step 3: Add glass fiber to the mixed solution A, and heat and stir again until the glass fiber is completely melted to obtain a mixed solution B;

[0010] Step 4: Casting and rolling: The mixed solution B is cast and rolled multiple times to obtain a cast-rolled material with a thickness of 2.25-2.3 mm;

[0011] First pass: The cast material is sent to the cold rolling mill with an inlet thickness of 2.0 mm, an intermediate thickness of 1.9 mm, and an outlet thickness of 1.8 mm. The spraying rate is 45-50%, and cast material A is obtained.

[0012] First puncture: Micro-hole puncture treatment is performed on the edges of the cast material A;

[0013] Second pass: The punctured cast material A is sent to a cold rolling mill with an inlet thickness of 1.7 mm, an intermediate thickness of 1.5 mm, and an outlet thickness of 1.3 mm. The spraying rate is 45-50%, thereby obtaining cast material B.

[0014] First trimming: Send the cast material B to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material B;

[0015] First puncture: perform micro-hole puncture treatment on the edges of the cast material B after trimming;

[0016] First annealing: annealing treatment;

[0017] The third pass: the annealed cast material B is sent to the cold rolling mill. The inlet thickness of the cold rolling mill is 1.1 mm, the middle thickness is 0.8 mm, the outlet thickness is 0.5 mm, and the spraying amount is 45-50% to obtain the cast material C.

[0018] The fourth pass: the cast material C is sent to the cold rolling mill, the inlet thickness of the cold rolling mill is 0.4mm, the middle thickness is 0.3mm, the outlet thickness is 0.2mm, and the spraying amount is 40-50% to obtain the cast material D;

[0019] Second trimming: Send the cast material D to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material D;

[0020] Second annealing: annealing treatment;

[0021] The fifth pass: the annealed cast material D is sent to the cold rolling mill. The inlet thickness of the cold rolling mill is 0.15 mm, the middle thickness is 0.1 mm, the outlet thickness is 0.08 mm, and the spraying amount is 45-50% to obtain the cast material E.

[0022] The sixth pass: the cast material E is sent to the cold rolling mill, the inlet thickness of the cold rolling mill is 0.06mm, the middle thickness is 0.05mm, the outlet thickness is 0.03mm, and the spraying amount is 30-40% to obtain the cast material F;

[0023] Third trimming: Send the cast material F to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material F;

[0024] Step 6: Cutting and testing;

[0025] Step 7: Packing and warehousing.

[0026] As a further improvement, the stirring device in step 2 is an electromagnetic stirring device.

[0027] As a further improvement, sandblasting is performed after the sixth pass in step five. Sandblasting has the advantage of avoiding oxidation, and can remove tiny burrs on the surface of the substrate, thereby improving the surface smoothness of the substrate, improving the depression and mechanical properties of the substrate surface, and extending the service life of the substrate.

[0028] As a further improvement, the ratio of the glass fiber added in step three to the sum of the raw materials for making the mixed solution A is 1:99. After the glass fiber is added to the substrate, the tensile strength, elastic modulus, and heat resistance are effectively improved. At the same time, it has the characteristics of flame retardancy, insulation, low water absorption, high chemical properties, and low production cost.

[0029] As a further improvement, the smelting temperature of the raw materials in step 2 is 700-750° C., and the holding time is 2 hours.

[0030] As a further improvement, the temperature of the re-smelting in step three is 760-800° C., and the holding time is 1.5 hours.

[0031] As a further improvement, the battery foil substrate is applied in the field of new energy vehicles.

[0032] As a further improvement, during the detection in step six, a pinhole detection device is used to detect defects on the surface of the substrate.

[0033] Beneficial effects:

[0034] This device uses multiple puncture and trimming operations at the edge of the substrate to effectively reduce the risk of cracking of the substrate during the rolling process. After forming, the substrate is not easy to bend or crack when rolled, and has stronger chemical stability. It also solves the widespread defects of uneven tissue composition and component segregation in the substrate produced in the prior art by adding glass fiber and using a stirring device, improves the production yield and surface quality of aluminum foil, avoids the problems of a large number of pinholes and cracks, and meets the production of high-quality aluminum foil; improves the tensile strength and elongation of the substrate, which are relatively poor, so that the capacity of the battery in the substrate is expanded, the service life is extended, and the production cost of the substrate is reduced.

[0035] This device adds sandblasting work. Sandblasting has the advantage of avoiding oxidation and can remove tiny burrs on the surface of the substrate, thereby improving the surface smoothness of the substrate, improving the depression and mechanical properties of the substrate surface, and extending the service life of the substrate. DETAILED DESCRIPTION

[0036] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the examples. The examples are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0037] Example 1:

[0038] A specific embodiment of the present invention is a method for preparing a battery foil substrate to reduce edge cracking, comprising the following steps:

[0039] Step 1: Prepare raw materials: weigh the raw materials of corresponding specifications according to the preparation requirements and set aside;

[0040] Step 2: Pour the prepared raw materials into the smelting furnace in sequence and stir and melt them by a stirring device. When the raw materials are completely melted, a mixed solution A is obtained;

[0041] Step 3: Add glass fiber to the mixed solution A, and heat and stir again until the glass fiber is completely melted to obtain a mixed solution B;

[0042] Step 4: Casting and rolling: The mixed solution B is cast and rolled multiple times to obtain a cast-rolled material with a thickness of 2.25 mm;

[0043] First pass: The cast material is sent to the cold rolling mill with an inlet thickness of 2.0 mm, an intermediate thickness of 1.9 mm, an outlet thickness of 1.8 mm, and a spraying volume of 0% to obtain cast material A.

[0044] First puncture: Micro-hole puncture treatment is performed on the edges of the cast material A;

[0045] Second pass: The punctured cast material A is sent to a cold rolling mill with an inlet thickness of 1.7 mm, an intermediate thickness of 1.5 mm, and an outlet thickness of 1.3 mm. The spraying rate is 45-50%, thereby obtaining cast material B.

[0046] First trimming: Send the cast material B to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material B;

[0047] First puncture: perform micro-hole puncture treatment on the edges of the cast material B after trimming;

[0048] First annealing: annealing treatment;

[0049] The third pass: the annealed cast material B is sent to the cold rolling mill with an inlet thickness of 1.1 mm, an intermediate thickness of 0.8 mm, an outlet thickness of 0.5 mm, and a spraying volume of 50% to obtain cast material C;

[0050] The fourth pass: the cast material C is sent to the cold rolling mill, the inlet thickness of the cold rolling mill is 0.4mm, the middle thickness is 0.3mm, the outlet thickness is 0.2mm, and the spraying amount is 50%, to obtain the cast material D;

[0051] Second trimming: Send the cast material D to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material D;

[0052] Second annealing: annealing treatment;

[0053] The fifth pass: the annealed cast material D is sent to the cold rolling mill. The inlet thickness of the cold rolling mill is 0.15 mm, the middle thickness is 0.1 mm, the outlet thickness is 0.08 mm, and the spraying volume is 45% to obtain the cast material E.

[0054] The sixth pass: the cast material E is sent to the cold rolling mill, the inlet thickness of the cold rolling mill is 0.06mm, the middle thickness is 0.05mm, the outlet thickness is 0.03mm, and the spraying amount is 40%, to obtain the cast material F;

[0055] Third trimming: Send the cast material F to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material F;

[0056] Step 6: Cutting and testing;

[0057] Step 7: Packing and warehousing.

[0058] The stirring device in step 2 is an electromagnetic stirring device.

[0059] In step five, sandblasting is performed after the sixth pass. Sandblasting has the advantage of avoiding oxidation, and can remove tiny burrs on the surface of the substrate, thereby improving the surface smoothness of the substrate, improving the depression and mechanical properties of the substrate surface, and extending the service life of the substrate.

[0060] The ratio of the glass fiber added in step 3 to the sum of the raw materials for making the mixed solution A is 1:99. After the glass fiber is added to the substrate, the tensile strength, elastic modulus, and heat resistance are effectively improved. At the same time, it has the characteristics of flame retardancy, insulation, low water absorption, high chemical properties, and low production cost.

[0061] In step 2, the smelting temperature of the raw materials is 750° C. and the holding time is 2 hours.

[0062] The temperature of the re-smelting in step 3 is 800° C. and the holding time is 1.5 hours.

[0063] Battery foil substrates are used in the field of new energy vehicles.

[0064] During the inspection in step six, a pinhole detection device is used to detect defects on the surface of the substrate.

[0065] Example 2:

[0066] A specific embodiment of the present invention is a method for preparing a battery foil substrate to reduce edge cracking, comprising the following steps:

[0067] Step 1: Prepare raw materials: weigh the raw materials of corresponding specifications according to the preparation requirements and set aside;

[0068] Step 2: Pour the prepared raw materials into the smelting furnace in sequence and stir and melt them by a stirring device. When the raw materials are completely melted, a mixed solution A is obtained;

[0069] Step 3: Add glass fiber to the mixed solution A, and heat and stir again until the glass fiber is completely melted to obtain a mixed solution B;

[0070] Step 4: Casting and rolling: The mixed solution B is cast and rolled multiple times to obtain a cast-rolled material with a thickness of 2.3 mm;

[0071] First pass: The cast material is sent to the cold rolling mill with an inlet thickness of 2.0 mm, an intermediate thickness of 1.9 mm, an outlet thickness of 1.8 mm, and a spraying volume of 0% to obtain cast material A.

[0072] First puncture: Micro-hole puncture treatment is performed on the edges of the cast material A;

[0073] Second pass: The punctured cast material A is sent to a cold rolling mill with an inlet thickness of 1.7 mm, an intermediate thickness of 1.5 mm, and an outlet thickness of 1.3 mm. The spraying rate is 45-50%, thereby obtaining cast material B.

[0074] First trimming: Send the cast material B to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material B;

[0075] First puncture: perform micro-hole puncture treatment on the edges of the cast material B after trimming;

[0076] First annealing: annealing treatment;

[0077] The third pass: the annealed cast material B is sent to the cold rolling mill with an inlet thickness of 1.1 mm, an intermediate thickness of 0.8 mm, an outlet thickness of 0.5 mm, and a spraying volume of 50% to obtain cast material C;

[0078] The fourth pass: the cast material C is sent to the cold rolling mill, the inlet thickness of the cold rolling mill is 0.4mm, the middle thickness is 0.3mm, the outlet thickness is 0.2mm, and the spraying amount is 50%, to obtain the cast material D;

[0079] Second trimming: Send the cast material D to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material D;

[0080] Second annealing: annealing treatment;

[0081] The fifth pass: the annealed cast material D is sent to the cold rolling mill. The inlet thickness of the cold rolling mill is 0.15 mm, the middle thickness is 0.1 mm, the outlet thickness is 0.08 mm, and the spraying amount is 50% to obtain the cast material E.

[0082] The sixth pass: the cast material E is sent to the cold rolling mill, the inlet thickness of the cold rolling mill is 0.06mm, the middle thickness is 0.05mm, the outlet thickness is 0.03mm, and the spraying amount is 40%, to obtain the cast material F;

[0083] Third trimming: Send the cast material F to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material F;

[0084] Step 6: Cutting and testing;

[0085] Step 7: Packing and warehousing.

[0086] The stirring device in step 2 is an electromagnetic stirring device.

[0087] In step five, sandblasting is performed after the sixth pass. Sandblasting has the advantage of avoiding oxidation, and can remove tiny burrs on the surface of the substrate, thereby improving the surface smoothness of the substrate, improving the depression and mechanical properties of the substrate surface, and extending the service life of the substrate.

[0088] The ratio of the glass fiber added in step 3 to the sum of the raw materials for making the mixed solution A is 1:99. After the glass fiber is added to the substrate, the tensile strength, elastic modulus, and heat resistance are effectively improved. At the same time, it has the characteristics of flame retardancy, insulation, low water absorption, high chemical properties, and low production cost.

[0089] In step 2, the smelting temperature of the raw materials is 750° C. and the holding time is 2 hours.

[0090] The temperature of the re-melting in step 3 is 780° C. and the holding time is 1.5 hours.

[0091] Battery foil substrates are used in the field of new energy vehicles.

[0092] During the inspection in step six, a pinhole detection device is used to detect defects on the surface of the substrate.

[0093] The battery foil substrate prepared by the preparation method of the present invention has a tensile strength of ≥260 MPa and an elongation of ≥4.0%. Therefore, the preparation method of the present invention can solve the problems of low tensile strength, low elongation and easy cracking of the existing battery foil substrate.

[0094] 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, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0095] The above description is merely a preferred embodiment of the present invention and therefore cannot be used to limit the scope of the present invention. In other words, equivalent changes and modifications made according to the scope of the present invention and the contents of the specification should still fall within the scope of the present invention.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A preparation method for reducing edge cracking of battery foil substrate, characterized in that: The following steps are involved: Step 1: Prepare raw materials: weigh the raw materials of corresponding specifications according to the preparation requirements and set aside; Step 2: Pour the prepared raw materials into the smelting furnace in sequence and stir and melt them by a stirring device. When the raw materials are completely melted, a mixed solution A is obtained; Step 3: adding glass fiber to the mixed solution A in a ratio of 1:99 between the glass fiber and the sum of the raw materials for making the mixed solution A, and heating and stirring again until the glass fiber is completely melted to obtain a mixed solution B; Step 4: Casting and rolling: The mixed solution B is cast and rolled multiple times to obtain a cast-rolled material with a thickness of 2.25-2.3 mm; First pass: The cast material is sent to the cold rolling mill. The inlet thickness of the cold rolling mill is 2.0mm, the middle thickness is 1.9mm, the outlet thickness is 1.8mm, and the spraying volume is 45-50% to obtain cast material A. First puncture: Micro-hole puncture treatment is performed on the edges of the cast material A; Second pass: The punctured cast material A is sent to a cold rolling mill with an inlet thickness of 1.7 mm, an intermediate thickness of 1.5 mm, and an outlet thickness of 1.3 mm. The spraying rate is 45-50%, and cast material B is obtained. First trimming: Send the cast material B to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material B; First puncture: perform micro-hole puncture treatment on the edges of the cast material B after trimming; First annealing: annealing treatment; The third pass: the annealed cast material B is sent to the cold rolling mill. The inlet thickness of the cold rolling mill is 1.1mm, the middle thickness is 0.8mm, the outlet thickness is 0.5mm, and the spraying volume is 45-50% to obtain cast material C. The fourth pass: the cast material C is sent to the cold rolling mill. The inlet thickness of the cold rolling mill is 0.4mm, the middle thickness is 0.3mm, the outlet thickness is 0.2mm, and the spraying volume is 40-50% to obtain the cast material D. Second trimming: Send the cast material D to the trimming machine for trimming, and completely remove the cracked parts around the edges of the cast material D; Second annealing: annealing treatment; The fifth pass: the annealed cast material D is sent to the cold rolling mill. The inlet thickness of the cold rolling mill is 0.15mm, the middle thickness is 0.1mm, the outlet thickness is 0.08mm, and the spraying volume is 45-50% to obtain the cast material E. The sixth pass: the cast material E is sent to the cold rolling mill. The inlet thickness of the cold rolling mill is 0.06mm, the middle thickness is 0.05mm, the outlet thickness is 0.03mm, and the spraying volume is 30-40% to obtain the cast material F. The third trimming: the cast material F is sent to the trimming machine for trimming, and the cracked parts around the edges of the cast material F are completely removed; Step 5: Cutting and testing; Step 6: Packing and storage.

2. The method for reducing edge cracking of a battery foil substrate according to claim 1, characterized in that: The stirring device in step 2 is an electromagnetic stirring device.

3. The method for reducing edge cracks in a battery foil substrate according to claim 1, characterized in that: In the step 4, sandblasting is performed after the sixth pass.

4. The method for reducing edge cracks in a battery foil substrate according to claim 1, wherein: The smelting temperature of the raw materials in step 2 is 700-750° C., and the holding time is 2 hours.

5. The method for preparing a battery foil substrate to reduce edge cracking according to claim 1, characterized in that: The temperature of the re-smelting in the step 3 is 760-800° C., and the holding time is 1.5 hours.

6. The method for preparing a battery foil substrate to reduce edge cracking according to claim 1, characterized in that: The battery foil substrate is used in the field of new energy vehicles.

7. The method for reducing edge cracks in a battery foil substrate according to claim 1, characterized in that: During the detection in step five, a pinhole detection device is used to detect defects on the surface of the substrate.