A battery zinc negative material forming process

Abstract

The application discloses a battery zinc negative material forming process, comprising the following steps: 1), preparing pure zinc ingot; 2), homogenizing annealing the ingot obtained in step 1); 3), rolling the blank obtained in step 2) after heat preservation at 280-300 DEG C to form a plate strip with a thickness of 1.0-2.0 mm; 4), after annealing the plate blank obtained in step 3) at 270-300 DEG C for 20-40 min, first pass rolling is carried out, and the plate blank is rolled for 5-10 times; after the first pass rolling is completed, the thickness of the plate blank is reduced to 0.3-1.0 mm; 5), folding the plate blank obtained in step 4), annealing at 270-300 DEG C for 20-40 min, and then carrying out second pass rolling, folding and rolling for 5-10 times, and the rolling direction of the second pass is parallel to that of the first pass; after the second pass rolling is completed, the thickness of the plate blank is 0.4-0.8 mm; 6), the plate blank obtained in step 5) is used by tearing the overlapping part and taking the metal contact surface. The application can reduce the possibility of dendrite formation, thereby prolonging the service life of the battery.

Description

Technical Field

[0001] This invention relates to a forming process for zinc anode materials for batteries, belonging to the field of zinc alloy battery anode forming and processing technology. Background Technology

[0002] Zinc-ion batteries have attracted widespread attention due to their safety and low raw material prices. However, factors such as zinc dendrites and passivation films on the zinc anode surface reduce the battery's lifespan and electrochemical performance. Summary of the Invention

[0003] To overcome the problems existing in the prior art, this invention provides a forming process for zinc anode materials in batteries, which increases the specific surface area during the reaction. This makes the deposition of zinc ions back to the zinc anode more uniform during battery charging, reducing the possibility of dendrite formation and thus extending battery life. The specific technical solution is as follows.

[0004] A forming process for a zinc anode material for batteries, characterized by comprising the following steps:

[0005] 1) Preparation of pure zinc ingots;

[0006] 2) The ingot obtained in step 1) is subjected to homogenization annealing;

[0007] 3) After holding the billet obtained in step 2) at 280℃-300℃, roll it into a sheet or strip with a thickness of 1.0-2.0mm;

[0008] 4) After annealing the slab obtained in step 3) at 270℃-300℃ for 20-40 minutes, perform the first rolling pass 5-10 times, with the axial direction of the rolls parallel to the short axis of the slab; after the first rolling pass, the thickness of the slab is reduced to 0.3-1.0 mm.

[0009] 5) Fold the slab obtained in step 4) in half, anneal it at 270℃-300℃ for 20-40 minutes, and then roll it in the second pass. Roll it 5-10 times. The rolling direction of the second pass is parallel to that of the first pass. After the second pass rolling, the thickness of the slab is 0.4-0.8 mm.

[0010] 6) Tear apart the overlapping parts of the slab obtained in step 5) and use the metal contact surface.

[0011] Furthermore, the homogenization annealing process is as follows: hold at 250℃-310℃ for 20-28 hours.

[0012] Furthermore, in step 3), the billet is kept at 280℃-300℃ for 2-3 hours.

[0013] Furthermore, the first rolling pass has a roll speed of 180-210 r / min and a roll diameter of 100 mm.

[0014] Furthermore, the rolling speed of the second pass is increased by 10-30 r / min compared to the first pass; the temperature drops rapidly during the rolling process, and increasing the rolling speed of the second pass helps to avoid the rapid temperature drop and ensure the rolling effect.

[0015] The forming process used in this invention, due to uneven plastic deformation, results in local soft and hard surfaces being squeezed together after folding, causing the inner layer to be embedded on both sides (contact surfaces). The metal interface after tearing is in a frosted state, which increases the specific surface area during battery reaction. This makes the zinc ions return to the zinc negative electrode for deposition more uniformly when the battery is charging, reducing the possibility of dendrite formation and thus extending the battery's lifespan. Attached Figure Description

[0016] Figure 1 This is the charge-discharge curve of sample 1 in Example 1;

[0017] Figure 2 This is the charge-discharge curve of sample 2 in Example 1;

[0018] Figure 3 This is the charge-discharge curve of sample 3 in Example 1;

[0019] Figure 4 This is the charge-discharge curve of sample 4 in Example 1;

[0020] Figure 5 This is the charge-discharge curve of sample 1 in Example 2;

[0021] Figure 6 This is the charge-discharge curve of sample 2 in Example 2;

[0022] Figure 7 This is the charge-discharge curve of sample 3 in Example 2;

[0023] Figure 8 This is the charge-discharge curve of sample 4 in Example 2;

[0024] Figure 9 This is the charge-discharge curve of sample 1 in Example 3;

[0025] Figure 10 This is the charge-discharge curve of sample 2 in Example 3;

[0026] Figure 11 This is the charge-discharge curve of sample 3 in Example 3;

[0027] Figure 12 This is the charge-discharge curve of sample 4 in Example 3;

[0028] Figure 13 This is the charge-discharge curve of sample 1 in Example 4;

[0029] Figure 14 This is the charge-discharge curve of sample 2 in Example 4;

[0030] Figure 15 This is the charge-discharge curve of sample 3 in Example 4;

[0031] Figure 16 This is the charge-discharge curve of sample 4 in Example 4;

[0032] Figure 17 This is a photograph of the contact surface of the slab of Sample 1 in Example 4 after it has been torn open;

[0033] Figure 18 This is a photograph of the rolled surface of the slab of Sample 1 in Example 4;

[0034] Figure 19 This is a scanning electron microscope image of the rolled surface of the slab of Sample 1 in Example 4;

[0035] Figure 20 This is a scanning electron microscope image of the contact surface of the slab of Sample 1 in Example 4 after it has been torn open;

[0036] Figure 21 This is a graph showing the long-cycle performance of sample 3 in Example 1;

[0037] Figure 22 This is a graph showing the long-cycle performance of sample 1 in Example 4. Detailed Implementation

[0038] Example 1

[0039] Raw materials were melted in a 500 kg capacity smelting furnace, and pure zinc ingots with a width of 300 mm, a thickness of 100 mm, and a length of 2300 mm were semi-continuously cast and machined. The ingots were then subjected to homogenization annealing at 310℃ for 20 hours, followed by natural cooling. After holding the ingots at 300℃ for 2 hours, they were rolled to obtain approximately several strips with a width of 300 mm, a thickness of 1 mm, and a length of 2000 mm. Further experiments showed that homogenization annealing at 250℃-310℃ for 20-28 hours achieved good homogenization results, and annealing at 280℃-300℃ for 2-3 hours before rolling also yielded good annealing results.

[0040] (1) Take 4 pieces of cut strip and directly perform the first pass of cold rolling. Adjust the rolls to the appropriate opening, rotate at 180 r / min, roll diameter 100 mm, and repeatedly roll along the long axis direction (i.e. the length direction, which is also the rolling direction; the axial direction of the roll is perpendicular to the short axis (width) direction of the slab) for 5-10 times, reducing the thickness of the slab to 0.5 mm; then fold 2 pieces in half, and leave the remaining 2 pieces unfolded, and continue the second pass of cold rolling. Cold roll the folded slab to 0.4 mm, and the unfolded slab to 0.2 mm.

[0041] (2) Tear apart the folded rolled zinc sheet to obtain Sample 1 and Sample 2, and take the contact surface (rough surface, non-rolled surface) of Sample 1 and Sample 2; the unfolded slab is Sample 3 and Sample 4, and take the rolled surface. Perform cycle performance tests on Sample 1-Sample 4, and the test results are as follows: Figures 1-4 As shown, the test results are compared in Table 1.

[0042] Table 1: Cyclic performance test results of four samples in Example 1

[0043] cold rolling Cycle time (h) Sample 1 109 Sample 2 174 Sample 3 49 Sample 4 53

[0044] Example 2

[0045] (1) Take 4 portions of the strip obtained after rolling in Example 1, anneal the strip at 180℃ for 30 min, and then roll it for the first pass. The roll speed is 200 r / min and the roll diameter is 100 mm. Roll it repeatedly 5-10 times along the long axis (i.e. the length direction, which is also the rolling direction) to reduce the thickness of the slab to 0.5 mm. Then fold 2 portions in half and leave the remaining 2 portions unfolded. After annealing at 180℃ for 30 min, continue rolling for the second pass. Roll the folded slab to 0.4 mm and the unfolded slab to 0.2 mm.

[0046] (2) Tear apart the folded rolled zinc sheet to obtain Sample 1 and Sample 2, and take the contact surface (rough surface, non-rolled surface) of Sample 1 and Sample 2; the unfolded slab is Sample 3 and Sample 4, and take the rolled surface. Perform cycle performance tests on Sample 1-Sample 4, and the test results are as follows: Figures 5-8 As shown in the figure, the test results are compared in Table 2.

[0047] Table 2: Cyclic performance test results of four samples in Example 2

[0048]

[0049]

[0050] Example 3

[0051] (1) Take 4 portions of the strip obtained after rolling in Example 1, anneal the strip at 270℃ for 40 min, and then roll it for the first pass. The roll speed is 200 r / min and the roll diameter is 100 mm. Roll it repeatedly 5-10 times along the long axis (i.e. the length direction, which is also the rolling direction) to reduce the thickness of the slab to 0.5 mm. Then fold 2 portions in half and leave the remaining 2 portions unfolded. After annealing at 270℃ for 40 min, continue rolling for the second pass. Roll the folded slab to 0.4 mm and the unfolded slab to 0.2 mm.

[0052] (2) Tear apart the folded rolled zinc sheet to obtain Sample 1 and Sample 2, and take the contact surface (rough surface, non-rolled surface) of Sample 1 and Sample 2; the unfolded slab is Sample 3 and Sample 4, and take the rolled surface. Perform cycle performance tests on Sample 1-Sample 4, and the test results are as follows: Figures 9-12 As shown in the figure, the test results are compared in Table 3.

[0053] Table 3: Cyclic performance test results of four samples in Example 3

[0054] Rolling at 270℃ Cycle time (h) Sample 1 170 Sample 2 85 Sample 3 66 Sample 4 58

[0055] Example 4

[0056] (1) Take 4 portions of the strip obtained after rolling in Example 1, anneal the strip at 300℃ for 20 minutes, and then roll it for the first pass. The roll speed is 210 r / min and the roll diameter is 100 mm. Roll it repeatedly 5-10 times along the long axis (i.e. the length direction, which is also the rolling direction) to reduce the thickness of the strip to 0.5 mm. Then fold 2 portions in half and leave the remaining 2 portions unfolded. After annealing at 300℃ for 20 minutes, continue rolling for the second pass. Roll the folded strip to 0.4 mm and the unfolded strip to 0.2 mm.

[0057] (2) Tear apart the folded rolled zinc sheet to obtain Sample 1 and Sample 2, and take the contact surface (rough surface, non-rolled surface) of Sample 1 and Sample 2; the unfolded slab is Sample 3 and Sample 4, and take the rolled surface. Perform cycle performance tests on Sample 1-Sample 4, and the test results are as follows: Figures 13-16 As shown, the test results are compared in Table 4. Among them, a photograph of the contact surface of sample 1 is shown below. Figure 17 As shown, the contact surface has a frosted finish and is relatively rough; a photograph of the rolled surface of sample 1 is shown below. Figure 18 As shown, the rolled surface is relatively smooth. Figure 19 , Figure 20The images are scanning electron microscope (SEM) images of the rolled surface and the contact surface of sample 1, respectively. It can be seen that the contact surface exhibits a large number of uniform "peaks and valleys", which increases the specific surface area during the reaction. This makes the zinc ions return to the zinc negative electrode for deposition more uniformly when the battery is charging, reducing the possibility of dendrite formation and thus extending the battery's lifespan.

[0058] By comparing the number of zinc-manganese full-cell cycle tests performed on sample 3 of Example 1 and sample 1 of Example 4, as shown... Figure 21 , Figure 22 As shown, the number of cycles for sample 1 in Example 4 was 468, while the number of cycles for sample 3 in Example 1 was only 50. It can be seen that the performance improvement of 300℃ folding rolling is very significant compared with ordinary cold rolling.

[0059] Table 4: Cyclic performance test results of four samples in Example 4

[0060] Rolling at 300℃ Cycle time (h) Sample 1 2800 Sample 2 318 Sample 3 70 Sample 4 61

[0061] The comparison of the four examples above shows that the performance of the sample rolled by folding is significantly better than that of the sample rolled without folding, and the rolling at a higher temperature (270-300℃) is better than that at a lower temperature (180℃) or cold rolling.

[0062] Meanwhile, further experiments showed that the first rolling pass after annealing at a higher temperature (270-300℃) to roll the slab to a thickness of 0.3-1.0 mm, and the second rolling pass to roll the folded slab to a thickness of 0.4-0.8 mm, both achieved similar results to Example 4.

[0063] Where there is no conflict, the embodiments and features described herein can be combined with each other. This invention is not limited to the specific embodiments described above; the specific embodiments described above are merely illustrative and not limiting. Those skilled in the art, under the guidance of this invention, can make many other modifications without departing from the spirit and scope of the claims, and all of these modifications fall within the scope of protection of this invention.

Claims

1. A forming process for zinc anode material in batteries, characterized in that, Includes the following steps: 1) Preparation of pure zinc ingots; 2) Perform homogenization annealing on the ingot obtained in step 1); 3) After holding the billet obtained in step 2) at 280℃-300℃, roll it into a sheet or strip with a thickness of 1.0-2.0mm; 4) After annealing the slab obtained in step 3) at 270℃-300℃ for 20-40 minutes, perform the first rolling pass 5-10 times, with the axial direction of the rolls parallel to the short axis of the slab; after the first rolling pass, the thickness of the slab is reduced to 0.3-1.0 mm. 5) Fold the slab obtained in step 4) in half, anneal it at 270℃-300℃ for 20-40 minutes, and then roll it in the second pass. Roll it 5-10 times. The rolling direction of the second pass is parallel to that of the first pass. After the second pass rolling, the thickness of the slab is 0.4-0.8 mm. 6) Tear apart the overlapping parts of the slab obtained in step 5) and use the metal contact surface; In step 3), the billet is held at 280℃-300℃ for 2-3 hours. The rolling speed of the second pass is increased by 10-30 r / min compared to the first pass.

2. The forming process for a zinc anode material for a battery according to claim 1, characterized in that, The homogenization annealing process is as follows: hold at 250℃-310℃ for 20-28 hours.

3. The forming process for a zinc anode material for a battery according to claim 1, characterized in that, The first rolling pass has a roll speed of 180-210 r / min and a roll diameter of 100 mm.

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