A rolling needle

Abstract

A winding needle comprises an outer cover and two opposing winding needle outer shell bodies, with a substrate clamping space formed between the two winding needle outer shell bodies. The winding needle outer shell body comprises a needle seat groove, an outer needle seat and a clamping needle are provided inside the needle seat groove, and the bottom of the needle seat groove extends outward to form a forming portion with a gradually decreasing cross-sectional area. A retractable winding needle outer shell sub-body is mounted on the forming portion via an adjustment assembly. Two or more latches are mounted on the winding needle outer shell sub-body, the lower ends of the latches extend into latch holes in the forming portion, and a latch connecting rod body is mounted in the latch connecting rod hole. The bottom of the latch has a first inclined surface, and the latch connecting rod body has a second inclined surface corresponding to the first inclined surface. A magnetic attraction member is provided between the winding needle outer shell sub-body and the forming portion. The present invention increases the internal interlayer space of the winding core by dynamically adjusting the overall outer perimeter of the winding needle during the winding process of the battery core, effectively solving the problem of "S-shaped" deformation of the battery core caused by the contraction of the pole piece and the isolation membrane due to tension and the expansion of the pole piece during winding.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a winding needle. Background Art

[0002] With the development of the electric vehicle market, demand for batteries is increasing, and the demand for battery capacity is increasing. Consequently, battery cells are becoming increasingly thicker. Most lithium-ion batteries for electric vehicles still utilize a wound-type structure, but "S-shaped" deformation is a common problem in wound structures, especially as the core thickness increases. There are two main reasons for this phenomenon: 1) The winding process: During the winding process, a certain amount of tension is applied to the positive electrode sheet, negative electrode sheet, and separator in the direction of the tape to ensure proper alignment between the positive, negative electrode sheets, and separator, thereby ensuring the safety of the battery cell structure. However, this tension applied during the winding process causes the electrode sheets and separator to stretch longitudinally, while also exerting outward tension on the winding core, resulting in a relatively small roll diameter between the electrode sheets. Upon completion of the winding process, the tension on the electrode sheets and separator is released, causing a certain amount of contraction. The electrode sheet shrinks relatively little, while the separator shrinks significantly longitudinally. Consequently, the electrode sheet is squeezed and deformed, resulting in an "S-shaped" deformation. 2) Electrochemical Expansion: During the use of lithium-ion batteries, the thickness of the positive and negative electrodes changes. This is due to the release of rolling stress and the electrochemical expansion of the electrodes. According to existing data, the thickness expansion rate of positive electrodes is approximately 4%, while that of negative electrodes is as high as 20% or more. A key factor in this electrochemical expansion is the nature of graphite. When lithium is inserted into the negative electrode graphite, the lattice spacing changes, leading to microscopic internal stresses that cause the negative electrode to expand. This expansion, caused by these factors, causes an "S-shaped" deformation of the winding core, creating voids between the electrode and the separator, and resulting in dead zones in the electrode, ultimately affecting the long-term cycle performance and safety of the battery. Summary of the Invention

[0003] The purpose of the present invention is to provide a winding needle for solving the problem of deformation of lithium-ion battery winding, aiming to solve the problem of "S-shaped" deformation of the battery cell caused by tensile contraction of the pole piece and the isolation membrane and expansion of the pole piece in the existing battery winding process.

[0004] The technical solution of the present invention is: it includes an outer cover and two oppositely arranged winding needle jacket main bodies, a substrate clamping space is formed between the two winding needle jacket main bodies, the winding needle jacket main body includes a needle seat groove, an outer needle seat and a clamping needle are provided inside the needle seat groove, the bottom of the needle seat groove extends outward to form a forming part with a gradually decreasing cross-sectional area, the retractable winding needle jacket sub-body is installed on the forming part through an adjustment component, more than two pins are installed on the winding needle jacket sub-body, the lower end of the pin extends into the pin hole of the forming part, the pin connecting rod body for pushing the pin to move is installed in the pin connecting rod hole that is perpendicular to the pin hole, the bottom of the pin is provided with a sloped surface one, and the pin connecting rod body is provided with a sloped surface two corresponding to the sloped surface one; a magnetic attraction part is provided between the winding needle jacket sub-body and the forming part.

[0005] The latch connecting rod body is arranged along a length direction parallel to the clamping needle, a plurality of latch bosses are arranged on the latch connecting rod body, and the second inclined surface is arranged on the latch bosses.

[0006] The latch boss is an oblique cylindrical shape, the second oblique surface is the bottom surface of the oblique cylinder, and the angle between the second oblique surface and the horizontal plane is the boss oblique angle b of the latch link, b=125-165°; the latch link rod body is a rectangular bar, and the latch boss is arranged on the rectangular bar; the latch link hole consists of a semicircular hole portion and a square guide groove portion, the square guide groove portion cooperates with the rectangular bar, and the semicircular hole portion cooperates with the latch boss.

[0007] The magnetic attraction component comprises an upper magnet mounted on the bottom of the winding needle outer shell auxiliary body and a lower magnet mounted on the end surface of the forming part. The winding needle outer shell auxiliary body is mounted on the end surface of the forming part.

[0008] The pin head is a long strip structure with two mounting holes at both ends of the pin head. A countersunk hole is provided on the winding needle outer shell auxiliary body for assembly with the pin head. Two threaded holes corresponding to the mounting holes are provided on the winding needle outer shell auxiliary body at the bottom of the countersunk hole. The bolts are installed in the threaded holes on the winding needle outer shell auxiliary body through the mounting holes.

[0009] A fine-tuning gasket is provided at the countersunk hole, and a clearance hole for the clearance bolt and the latch rod is provided on the fine-tuning gasket.

[0010] The bottom of the latch is composed of a plane portion and a first inclined surface, and a round chamfer is provided between the plane portion and the first inclined surface.

[0011] The radius of the round chamfer is 0.2-1.0 mm, and the angle between the inclined surface 1 and the flat surface is the bevel angle a of the bottom of the pin, a=15-55°.

[0012] The two coiled needle jacket bodies form a spindle-shaped structure.

[0013] The plurality of latch bosses are arranged on the latch connecting rod body at equal intervals.

[0014] Compared with the existing conventional needle rolling technology, the practical effects of the present invention are:

[0015] 1. When winding a lithium-ion battery, the present invention allows the forward and backward movement of the latch link. When the latch link moves forward, the boss on the latch link pushes the latch outward, separating the upper and lower magnets and simultaneously pushing the winding needle housing assembly and the winding needle housing assembly apart. When the winding needle housing assembly moves outward a certain distance, the wound pole piece and separator are simultaneously expanded outward. That is, the circumference of the subsequent winding layer (pole piece and separator length) is increased, thereby reserving space for the pole piece and separator to contract under tension, as well as space for graphite expansion.

[0016] 2. When the latch link moves backward, the upper and lower magnets are attracted, and the winding needle housing is reset. After the winding core is withdrawn from the winding needle, the tension of the pole piece and the isolation film is released, and the interlayer spacing of the winding core from the inside to the outside is restored to the same state in a natural state, that is, the tightness of the inner and outer rings is balanced.

[0017] 3. The present invention is easy to implement and has a good winding effect, which greatly improves the "S-shaped" deformation of the core caused by the expansion of the core, and ultimately improves the long-term cycle performance and safety of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the present invention;

[0019] Figure 2 It is a schematic diagram of the transverse cross-sectional structure of the present invention;

[0020] Figure 3 It is a schematic diagram of the longitudinal cross-sectional structure of the present invention;

[0021] Figure 4 This is a schematic diagram of the assembly of the latch;

[0022] Figure 5 It is a schematic diagram of the structure of the moving needle seat and its components;

[0023] Figure 6 Schematic diagram of the structure of the latch;

[0024] Figure 7 Schematic diagram of the structure of the latch connecting rod;

[0025] In the figure: 1-outer cover, 2-winding needle jacket main body, 3-winding needle jacket auxiliary body, 4-latch connecting rod, 5-latch, 6-upper magnet, 7-lower magnet, 8-fine-tuning gasket, 9-outer needle seat 1, 10-clamping needle 1, 11-latch connecting rod hole, 12-outer needle seat 2, 13-thimble, 14-roller, 15-clamping needle 2, 16-slide rod, 17 movable needle seat. DETAILED DESCRIPTION

[0026] In order to make the purpose and technical solution of the present invention more clearly presented to everyone, the following description is combined with the accompanying drawings and specific implementation methods to further explain the technology of the present invention in detail.

[0027] Figure 1 、 2In Figures 3, 4, and 5, the present invention comprises an outer cover 1 and a needle winding outer sleeve. The needle winding outer sleeve comprises a main needle winding outer sleeve 2 and a secondary needle winding outer sleeve 3. The main needle winding outer sleeve 2 is internally provided with an outer needle holder and a needle clamp, forming the main structure of the needle winding. The main needle winding outer sleeve 2 is further provided with a latch link 4, while the secondary needle winding outer sleeve 3 is provided with a latch 5 and an upper magnet 6. The latch 5, upper magnet 6, and the latch link 4 and lower magnet 7 provided in the main needle winding outer sleeve 2 form a linkage mechanism. Except for the outer cover 1, the remaining components are symmetrical. The secondary needle winding outer sleeve 3 has a width of 5mm-20mm. A latch link hole 11, formed by combining a square and semicircular shape, is provided in the thickness region of the main needle winding outer sleeve 2. The latch link 4 is located in this latch link hole 11. The latch link 4 is provided with five evenly spaced latch bosses. Five evenly spaced latch holes are provided at the junction of the main needle winding outer sleeve 2 and the secondary needle winding outer sleeve 3. The latch 5 is fixed to the winding needle jacket sub-body 3 through the latch positioning hole, and there are 5 latches. A fine-tuning gasket is set at the upper end of the latch positioning hole. The thickness of the fine-tuning gasket can adjust the stroke of the winding needle jacket sub-body. The thickness of the fine-tuning gasket is 0.2mm~2.0mm. A fixed lower magnet 7 is provided on the joint end of the winding needle jacket main body 2 and the winding needle jacket sub-body 3, and the number of lower magnets 7 is 4. A fixed upper magnet 6 is provided on the joint end of the winding needle jacket sub-body 3 and the winding needle jacket main body 2, and the number of upper magnets 6 is 4, which are attracted to the lower magnet 7 on the winding needle jacket main body 2. The outer needle seat includes an outer needle seat 1 9 and an outer needle seat 2 12. The clamping needle includes a clamping needle 10 and a clamping needle 2 15. The outer needle seat 2 12 and the clamping needle 10 are fixed on the outer cover 1 to form a fixed integral part. A movable needle holder 17 is located within the outer housing. This holder, along with slide bars 161 and 162, forms a sliding element. External needle holder 1 (9), clamping needle 15 (2), and roller 14 are secured to this holder, forming a single, movable component. When the winding needle is in the standby state, clamping needles 10 and 15 form a clamping space. When the isolation diaphragm is inserted into this clamping space, ejector pin 13 in the circular hole at the top of outer housing 1 moves forward. The tapered area at the front of ejector pin 13 pushes roller 14 sideways, simultaneously shifting the movable component sideways. At this point, clamping pins 10 and 15 close, clamping the isolation diaphragm.

[0028] Figure 6 In the figure, the head of the latch 5 is an elongated strip with two mounting holes at either end. The winding needle housing 3 is provided with a countersunk hole that mates with the head of the latch 5. Two threaded holes corresponding to the mounting holes are provided on the winding needle housing 3 at the bottom of the countersunk hole. Bolts are installed through the mounting holes in the threaded holes on the winding needle housing 3. A fine-tuning washer is provided at the countersunk hole, with a clearance hole for the bolt and the rod of the latch 5. The bottom of the latch 5 consists of a flat surface and a beveled surface (1). A chamfer is formed between the flat surface and the beveled surface (1). The radius of the chamfer is 0.2-1.0mm. The bevel angle a of the bottom of the latch 5 is the angle between the beveled surface (1) and the horizontal plane, a = 45°.

[0029] Figure 7In the figure, the latch boss is an oblique cylindrical shape, and the second oblique surface is the bottom surface of the oblique cylinder. The boss oblique angle b of the latch link is the angle between the second oblique surface and the horizontal plane, b=135°. The rod body of the latch link 4 is a rectangular bar, and the latch boss is set on the rectangular bar. The latch link hole 11 is composed of a semicircular hole portion and a square guide groove portion. The square guide groove portion cooperates with the rectangular bar, and the semicircular hole portion cooperates with the latch boss. The two edges below the rectangular bar have rounded corners, and the bottom of the square guide groove is provided with rounded corners corresponding to the rounded corners of the rectangular bar. The rounded corners facilitate the push of the latch link 4. The square portion of the latch link hole acts as a guide groove to prevent the latch link 11 from rotating. The semicircular portion is for corresponding to the semicircular boss on the latch link.

[0030] Directions:

[0031] The winding needle clamps 10 clamp the separator against each other before winding, adding the negative and positive electrodes during the process. When the winding reaches half the total number of layers, the latch link 4 moves forward. As the latch link 4 moves forward, the five equally spaced latch bosses on the latch link 4 push the latch 5 outward, which pushes the winding needle jacket sub-body 3 outward. Simultaneously, the magnet 6 on the winding needle jacket sub-body 3 separates from the lower magnet 7 on the winding needle jacket main body. After the winding core is completed, the latch link 4 moves backward, and the upper magnet 6 and lower magnet 7 are attracted to each other. At this time, the winding needle jacket sub-body 3 and the winding needle jacket main body 2 are reset.

[0032] Case description:

[0033] According to the method of use of the above invention, the application effect is illustrated in practice:

[0034] According to product design, there are the following parameters:

[0035]

[0036] According to experimental test data, the expansion coefficient of the positive electrode sheet is 4%, and the expansion coefficient of the negative electrode sheet is 22%, that is, the thickness of the core after full charge is 23.33mm; compared with the designed thickness of the core, the expanded thickness of the core at this time is 2.21mm.

[0037] Based on the core expansion thickness parameter, the space required between the core pole pieces is calculated as follows: 2.21 mm ÷ 66 layers = 0.033 mm. The winding needle housing assembly 3 begins moving outward when it reaches 1 / 2 of the total number of layers. Therefore, the total space required between layers due to this movement is 0.033 x 2 = 0.066 mm.

[0038] Layer spacing increase size inspection:

[0039] Take the positive electrode sheet as an example: when the spacing between layers increases, the increased thickness space is the increase in the diameter of the winding layer. According to the calculation formula: (C 针 ÷PI( )+H×(N*2-2))×PI( )=C 极 ,

[0040] Where: C 针 : circumference of the winding needle;

[0041] H: Single-layer electrode thickness + 0.066mm (including: single layer (positive electrode + negative electrode + isolation film * 2);

[0042] N: number of turns;

[0043] PI(): pi;

[0044] C 极 : Winding circumference, that is, the length of the pole piece required to calculate the number of turns.

[0045] When the starting number of circles is 33 / 2=16.5, take the 17th circle as the starting point. According to the calculation formula, the C of the original size and the new size 极 The value is calculated as follows:

[0046]

[0047] The new dimension is the change in the electrode circumference per revolution of the winding needle assembly. The calculated electrode circumference is used to determine whether the winding needle housing assembly 3 provides sufficient space for external movement. Because there is a small gap between the electrodes during winding, the actual required increase in interlayer space will be less than the theoretically calculated increase.

[0048] The present invention described above is merely a preferred embodiment of the present application and is not intended to limit the present invention. Those skilled in the art will be able to make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments described above. Any modifications, improvements, or substitutions made within the spirit and principles of the present invention shall be included within the scope of protection of the present application.

Claims

1. A needle coil, characterized in that: The invention comprises an outer cover (1), two oppositely arranged winding needle outer shell bodies (2), a substrate clamping space is formed between the two winding needle outer shell bodies (2), the winding needle outer shell body (2) comprises a needle seat groove, an outer needle seat and a clamping needle are arranged inside the needle seat groove, the bottom of the needle seat groove extends outward to form a forming part with a gradually reduced cross-sectional area, a retractable winding needle outer shell auxiliary body (3) is mounted on the forming part through an adjustment component, and two or more latches (5) are mounted on the winding needle outer shell auxiliary body (3), the lower end of the latch (5) extends into the latch hole of the forming part, and a latch connecting rod (4) for pushing the latch (5) to move is mounted on the latch hole. In the through-going latch connecting rod hole (11), the bottom of the latch (5) has an inclined surface 1, and the rod body of the latch connecting rod (4) is provided with an inclined surface 2 corresponding to the inclined surface 1; a magnetic attraction component is provided between the winding needle outer shell auxiliary body (3) and the forming part; the rod body of the latch connecting rod (4) is arranged along a length direction parallel to the clamping needle, and the rod body of the latch connecting rod (4) is provided with a plurality of latch bosses, and the inclined surface 2 is provided on the latch bosses; the magnetic attraction component includes an upper magnet (6) installed under the winding needle outer shell auxiliary body (3) and a lower magnet (7) installed on the end surface of the forming part, and the winding needle outer shell auxiliary body (3) is installed on the end surface of the forming part; Directions: The clamping needles are aligned to clamp the isolation membrane and then wound, and the negative electrode sheet and the positive electrode sheet are added during the process; when the winding reaches 1 / 2 of the total number of layers, the latch connecting rod (4) moves forward, and when the latch connecting rod (4) moves forward, the latch boss on the latch connecting rod (4) pushes the latch (5) to move outward, and the latch (5) pushes the winding needle jacket auxiliary body (3) to move outward, and at the same time, the magnet (6) on the winding needle jacket auxiliary body (3) is separated from the lower magnet (7) on the winding needle jacket main body; after the winding core is completed, the latch connecting rod (4) moves backward, and the upper magnet (6) and the lower magnet (7) are attracted, and at this time the winding needle jacket auxiliary body (3) and the winding needle jacket main body (2) are reset.

2. The winding needle according to claim 1, characterized in that: The latch boss is in the shape of an oblique cylinder, the second oblique surface is the bottom surface of the oblique cylinder, and the angle between the second oblique surface and the horizontal plane is the boss oblique angle b of the latch link, b=125-165°; the rod body of the latch link (4) is a rectangular bar, and the latch boss is arranged on the rectangular bar; the latch link hole (11) consists of a semicircular hole portion and a square guide groove portion, the square guide groove portion cooperates with the rectangular bar, and the semicircular hole portion cooperates with the latch boss.

3. The winding needle according to claim 1, characterized in that: The head of the latch (5) is a long strip structure, and two mounting holes are provided at both ends of the head of the latch (5). A countersunk hole is provided on the winding needle outer shell auxiliary body (3) for assembling with the head of the latch (5). Two threaded holes corresponding to the mounting holes are provided on the winding needle outer shell auxiliary body (3) at the bottom of the countersunk hole, and the bolts are installed in the threaded holes on the winding needle outer shell auxiliary body (3) through the mounting holes.

4. The winding needle according to claim 3, characterized in that: A fine-tuning gasket is provided at the countersunk hole, and a clearance hole for the rod of the clearance bolt and the latch (5) is provided on the fine-tuning gasket.

5. The winding needle according to claim 3, characterized in that: The bottom of the latch (5) consists of a plane portion and an inclined surface, and a round chamfer is provided between the plane portion and the inclined surface.

6. The winding needle according to claim 5, characterized in that: The radius of the round chamfer is 0.2-1.0 mm, and the angle between the inclined surface 1 and the flat surface portion is the bottom bevel angle a of the latch (5), a=15-55°.

7. The winding needle according to claim 1, characterized in that: The two needle jacket bodies (2) form a spindle-shaped structure.

8. The winding needle according to claim 1, characterized in that: The plurality of latch bosses are arranged equidistantly on the rod body of the latch connecting rod (4).

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