A baking structure for a lithium-ion large soft-pack electrode coil

Abstract

The present invention discloses a baking structure for a lithium-ion large soft-package pole roll, characterized in that it comprises a circular winding ring (1); a reserved foil pole roll (2) is wound on the outer surface of the winding ring (1); the outside of the reserved foil pole roll (2) is wrapped with a circular pole roll protective cover (3); wherein the winding ring (1) comprises an outer support ring (11) and an inner support ring (12); the outer support ring (11) and the inner support ring (12) are parallel to each other and arranged at intervals; the inner support ring (12) is located on the inner side of the outer support ring (11), and the two are fixedly connected by a plurality of support plates (13) distributed along the radial direction; the outer surface of the outer support ring (11) is wound with a reserved foil pole roll (2). The baking structure for a lithium-ion large soft-package pole roll disclosed by the present invention has a scientific structural design, can solve the problems of pole piece bending and pole roll decoiling after pole roll baking, and has great production practical significance.

Description

Technical Field

[0001] The invention relates to the technical field of lithium ion battery manufacturing, and in particular to a baking structure for a lithium ion large soft-package pole coil. Background Art

[0002] At present, lithium-ion batteries have the advantages of high specific energy, many cycles and long storage time. They are not only widely used in portable electronic devices (such as mobile phones, digital cameras and laptops), but also widely used in large and medium-sized electric equipment such as electric vehicles, electric bicycles and electric tools, becoming one of the most popular power sources. Therefore, the performance requirements for lithium-ion batteries are getting higher and higher.

[0003] Moisture is the natural enemy of lithium-ion batteries. For lithium-ion batteries, the moisture content of the pole coil must be controlled within a certain range. Therefore, the pole coil must be placed in an oven and undergo a baking process before it can be transferred to the subsequent circulation. However, the pole coil is prone to unwinding during and after the baking process. Unwinding means that the alignment of the pole coil side changes due to stress release during baking, which seriously affects the yield rate in battery production.

[0004] However, the existing technology is difficult to solve the problem of pole piece bending and unwinding after pole coil baking. Summary of the invention

[0005] The purpose of the present invention is to provide a baking structure for a lithium-ion large soft-package electrode coil in view of the technical defects in the prior art.

[0006] To this end, the present invention provides a baking structure for a lithium-ion large soft-package electrode roll, comprising a circular winding ring;

[0007] The outer surface of the winding ring is wound with a reserved foil pole coil;

[0008] The outside of the reserved foil pole coil is wrapped with a circular pole coil protection cover;

[0009] Wherein, the winding ring includes an outer support ring and an inner support ring;

[0010] The outer support ring and the inner support ring are parallel to each other and are arranged at intervals;

[0011] The inner support ring is located on the inner side of the outer support ring, and the two are fixedly connected by a plurality of support plates distributed along the radial direction;

[0012] The outer surface of the outer support ring is wound with a reserved foil pole roll.

[0013] The receiving ring is a large diameter receiving ring with an outer diameter ranging from 6 to 15 inches.

[0014] Among them, the specific heat of the pole coil protection cover material is lower than the specific heat of the pole piece foil in the reserved foil pole coil and the slurry coated on the pole piece foil.

[0015] Among them, the reserved foil pole roll includes the battery pole sheet foil body;

[0016] The battery pole sheet foil body has a longitudinally distributed active material area, and the surface of the active material area is coated with an active material layer;

[0017] The longitudinally distributed reserved foil material and foil tabs are distributed on the left and right sides of the active material area.

[0018] The active material area is close to one side edge of the reserved foil material, and has a longitudinally distributed cut active material of a preset width;

[0019] The right side of the cropped active material has a virtual crop line;

[0020] The virtual cutting line is the edge of the pole piece after the punching equipment performs the punching operation;

[0021] The width of the reserved foil is 2 to 4 mm.

[0022] Among them, the inner side of the inner support ring is provided with a pole piece winding shaft connecting hole for connecting with the pole piece winding shaft on the external pole piece slitting machine.

[0023] The outer surface of the inner support ring is fixedly connected to the outer support ring through four support plates distributed along the radial direction;

[0024] Any two adjacent support plates are distributed at equal intervals.

[0025] Wherein, there is an airflow cavity between any two adjacent support plates.

[0026] Among them, the following baking modes are adopted:

[0027] During the baking process, vacuuming in a preset high temperature environment and filling with inert gas in a preset high temperature environment are selected and performed alternately in cycles.

[0028] It can be seen from the technical solution provided by the present invention that, compared with the prior art, the present invention provides a baking structure for a large lithium-ion soft-pack pole coil, which has a scientific structural design and can solve the problems of pole piece bending and pole coil unwinding after pole coil baking, and has great production practical significance.

[0029] In addition, in order to shorten the baking process, the present invention can choose to evacuate in a high temperature (e.g., 70-90°C) environment and fill with inert gas in a high temperature (e.g., 70-90°C) environment during the baking process, and alternately cycle to reduce the moisture content of the electrode and impurities such as NMP, thereby improving the electrochemical performance of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of the three-dimensional structure of a baking structure of a lithium-ion large soft-package electrode coil provided by the present invention;

[0031] Figure 2 A front view of a baking structure of a lithium-ion large soft-package electrode coil provided by the present invention;

[0032] Figure 3 A schematic diagram of a section of the pole piece structure of a reserved foil pole roll after unfolding in a baking structure of a lithium-ion large soft-package pole roll provided by the present invention;

[0033] In the figure: 1 is a winding ring, 2 is a reserved foil pole coil, and 3 is a pole coil protection cover;

[0034] 11 is an outer support ring, 12 is an inner support ring, 13 is a support plate, 14 is a pole piece winding shaft connection hole, and 15 is an air flow cavity.

[0035] 20 is the battery electrode foil body, 21 is the foil ear, 22 is the active material area, 23 is the cut active material, 24 is the reserved foil, and 30 is the virtual cutting line. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation modes.

[0037] See also Figures 1 to 3 The present invention provides a baking structure for a lithium-ion large soft-package electrode roll, comprising a circular winding ring 1;

[0038] The outer surface of the winding ring 1 is wound with a reserved foil pole roll 2;

[0039] The outside of the reserved foil pole coil 2 is wrapped with a circular pole coil protection cover 3;

[0040] It should be noted that, for the present invention, in order to improve the yield rate of punching sheets, the pole piece is rolled and received on a large-diameter receiving ring 1. Before the pole roll (specifically the reserved foil pole roll 2) is baked, the outer layer of the pole roll is wrapped with a pole roll protective cover 3.

[0041] In the present invention, in a specific implementation, the collecting ring 1 is a large-diameter collecting ring with an outer diameter ranging from 6 to 15 inches, which can withstand high temperatures of 90 to 130 degrees without deformation, is lightweight, and can withstand the weight of the pole coil, thereby ensuring that the pole piece will not bend after baking, thereby improving the punching yield.

[0042] It should be noted that the weight of the take-up ring 1 should be as light as possible while being able to bear the weight of the pole coil.

[0043] In the present invention, in a specific implementation, the specific heat of the pole coil protective cover 3 material is lower than the specific heat of the pole piece foil in the reserved foil pole coil 2 and the slurry coated on the pole piece foil, and the gap is uniform, so that the moisture generated during the baking process can be drawn away from the gaps of the pole coil protective cover.

[0044] In the present invention, in a specific implementation, for the baking structure of the lithium ion large soft-pack electrode coil provided by the present invention, in order to shorten the baking process and save the baking time, the following baking mode is adopted:

[0045] During the baking process, vacuuming at a preset high temperature (e.g., 70-90°C) and filling with inert gas at a preset high temperature (e.g., 70-90°C) are performed alternately, which is beneficial to reducing the moisture content of the electrode and impurities such as NMP and improving the electrochemical performance of the battery.

[0046] It should be noted that during the baking process, high-temperature vacuuming and high-temperature inert gas, as well as multiple atmosphere cycles, can shorten the baking process and save baking time.

[0047] In the present invention, for specific implementation, see Figure 3 As shown, the reserved foil pole roll 2 includes a battery pole sheet foil body 20 (for example, the positive pole sheet foil body is aluminum foil, and the negative pole sheet foil body is copper foil);

[0048] The battery electrode foil body 20 has an active material region 22 distributed longitudinally, and the surface of the active material region 22 is coated with an active material layer (such as a positive electrode active material layer or a negative electrode active material layer);

[0049] The reserved foil material 24 and the foil tabs 21 are longitudinally distributed on the left and right sides of the active material area 22;

[0050] The active material area 22 is close to one side edge of the reserved foil 24 and has a longitudinally distributed cut active material 23 of a preset width;

[0051] The right side of the cut active material 23 has a virtual cutting line 30;

[0052] The virtual cutting line 30 is the edge of the pole piece after the punching equipment performs the punching operation.

[0053] In the present invention, in specific implementation, the width of the reserved foil 24 is preferably 2 to 4 mm. This can not only save the material cost of the foil, but also avoid blockage caused by the punching operation. In addition, the rolled pole coil does not need to be cut, and the punching operation can be carried out directly after the pole coil is baked.

[0054] It should be noted that in the present invention, the process route for battery production is: coating, rolling, slitting, baking, and punching. The coating process is to evenly coat the active material on the surface of the foil ear, and dry it to make it adhere to the surface of the foil ear. The rolling process is to use multiple large-tonnage round rollers under the action of a hydraulic press to roll the thickness of the pole piece to the thickness required by the customer. When the pole piece is rolled, the active material is extended, and it is difficult to ensure the alignment and uniform thickness of the edge of the active material. In order to improve this situation, the general process is to cut the pole piece after rolling, cut off the active material 23 and the reserved foil 24, and roll the pole piece into a pole roll. After the pole roll is baked and the moisture content is qualified, the pole roll is spread out for punching, that is, the pole roll is cut into pole pieces that meet customer requirements.

[0055] In the present invention, the cut active material 23 and the reserved foil 24 are not cut before baking, so stress will not be generated. During the baking process, no axial force will be generated due to stress release to cause the pole coil to unwind.

[0056] It should be noted that Figure 3 After the battery pole piece shown is rolled, the pole piece does not need to be cut, and the pole piece is directly punched after the pole roll is baked, thereby cutting off the active material 23 and the reserved foil 24 (adjacent to the cut active material).

[0057] Among them, the cut active materials and reserved foils are cut during the punching process, thereby eliminating the slitting process and improving the price advantage of lithium-ion batteries.

[0058] In the present invention, in specific implementation, the width of the cut active material 23 and the reserved foil 24 should be within the size range allowed by the punching machine mold and vacuum suction cup of the external battery electrode punching equipment, otherwise the vacuum pump is easily overloaded and causes electrode accumulation.

[0059] It should be noted that, as far as the present invention is concerned, not only can the battery pole pieces rolled by the battery pole piece rolling machine be free from the need for slitting process, but more importantly, it can solve the problem of pole coil unwinding after baking in the lithium-ion industry.

[0060] The present invention improves the structure of the pole coil and adopts a reserved foil pole coil, so as to realize a slitting-free process for lithium-ion power batteries. In a market environment where the cost of the lithium-ion battery industry is decreasing year by year, it saves a pole sheet slitting process, which is helpful to improve the production efficiency of the battery, reduce the production cost, and enhance the competitiveness of the battery products.

[0061] In the present invention, in specific implementation, the winding ring 1 includes an outer support ring 11 and an inner support ring 12;

[0062] The outer support ring 11 and the inner support ring 12 are parallel to each other and spaced apart;

[0063] The inner support ring 12 is located inside the outer support ring 11, and the two are fixedly connected by a plurality of support plates 13 distributed along the radial direction;

[0064] The outer surface of the winding ring 1 (specifically, the outer surface of the outer support ring 11) is wound with a reserved foil pole roll 2;

[0065] The outside of the reserved foil pole coil 2 is wrapped with a circular pole coil protection cover 3;

[0066] In the present invention, in a specific implementation, the inner side of the inner support ring 12 has a pole piece winding shaft connection hole 14 for connecting to the pole piece winding shaft on the external pole piece slitting machine (for example, the pole piece winding shaft is plugged into the pole piece winding shaft connection hole 14).

[0067] In the present invention, in a specific implementation, the outer support ring 11, the inner support ring 12 and the support plate 13 included in the winding ring 1 are integrally formed.

[0068] In the present invention, in a specific implementation, the outer surface of the inner support ring 12 is fixedly connected to the inner side surface of the outer support ring 11 through four support plates 13 distributed along the radial direction;

[0069] Any two adjacent support plates 13 are distributed at equal intervals.

[0070] It should be noted that, for the present invention, due to the structural design of the multiple support plates 13 distributed at equal intervals, the winding ring 1 of the present invention has a stable structure and a scientific design, which can prevent the winding ring 1 from being easily deformed during the baking process.

[0071] In the present invention, in a specific implementation, there is an air flow cavity 15 between any two adjacent support plates 13, so that after the pole coil is wound on the outer surface of the winding ring 1 and placed in the oven, the hot air flow inside the oven can flow freely in multiple directions such as the horizontal left and right direction, the front and back direction, and the up and down direction of the winding ring 1, with a good ventilation effect, thereby ensuring that the pole coil wound on the outer surface of the winding ring 1 has a better drying effect.

[0072] Based on the above technical solutions, it can be seen that the present invention can not only solve the problem of unwinding and bending of the pole piece after baking, overcome industry difficulties, but also shorten the baking process, save baking time, and eliminate the pole piece cutting process, effectively reducing battery costs.

[0073] In summary, compared with the prior art, the baking structure of a lithium-ion large soft-pack electrode coil provided by the present invention has a scientific structural design, can solve the problems of electrode sheet bending and electrode coil unwinding after electrode coil baking, and has great production practical significance.

[0074] In addition, in order to shorten the baking process, the present invention can select high temperature (e.g., 70-90°C) vacuuming and high temperature (e.g., 70-90°C) filling with inert gas during the baking process, and the cycles are alternating, which is beneficial to reducing the moisture content of the electrode and impurities such as NMP, thereby improving the electrochemical performance of the battery.

[0075] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A baking structure for a lithium-ion large soft-package electrode coil, characterized in that: The invention comprises a circular winding ring (1); a reserved foil pole roll (2) is wound on the outer surface of the winding ring (1); the outside of the reserved foil pole roll (2) is wrapped with a circular pole roll protection cover (3); the winding ring (1) comprises an outer support ring (11) and an inner support ring (12); the outer support ring (11) and the inner support ring (12) are parallel to each other and arranged at intervals; the inner support ring (12) is located on the inner side of the outer support ring (11), and the two are fixedly connected by a plurality of support plates (13) distributed along the radial direction; the outer surface of the outer support ring (11) is wound with a reserved foil pole roll (2), and one side edge of the reserved foil (24) of the reserved foil pole roll (2) has a longitudinally distributed and preset width of cut active material (23); the right side of the cut active material (23) has a virtual cutting The invention relates to a tangent line (30); the virtual cutting line (30) is the edge of the electrode after the punching equipment performs the punching operation; the reserved foil pole roll (2) comprises a battery electrode foil body (20); the battery electrode foil body (20) has a longitudinally distributed active material area (22), and the surface of the active material area (22) is coated with an active material layer; the inner side of the inner support ring (12) has a pole piece winding shaft connection hole (14) for connecting with the pole piece winding shaft on the external pole piece cutting machine; the outer surface of the inner support ring (12) is fixedly connected to the outer support ring (11) through four support plates (13) distributed along the radial direction; any two adjacent support plates (13) are evenly spaced; and there is an air flow cavity (15) between any two adjacent support plates (13).

2. The baking structure of the lithium-ion large soft-package electrode coil according to claim 1, characterized in that: The winding ring (1) is a large diameter winding ring with an outer diameter ranging from 6 to 15 inches.

3. The baking structure of the lithium-ion large soft-package electrode coil according to claim 1, characterized in that: The specific heat of the material of the pole coil protection cover (3) is lower than the specific heat of the pole piece foil in the reserved foil pole coil (2) and the slurry coated on the pole piece foil.

4. The baking structure of the lithium-ion large soft-package electrode coil according to claim 1, characterized in that: The reserved foil material (24) and the foil pole ears (21) distributed longitudinally are distributed on the left and right sides of the active material area (22).

5. The baking structure of the lithium-ion large soft-package electrode coil according to claim 1, characterized in that: The width of the reserved foil (24) is 2-4 mm.

6. The baking structure of a lithium-ion large soft-package electrode coil according to any one of claims 1 to 5, characterized in that: The following baking mode is adopted: during the baking process, vacuuming in a preset high temperature environment and filling with inert gas in a preset high temperature environment are selected, and the cycles are performed alternately.

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