Winding structure of cylindrical battery

Abstract

The utility model discloses a winding structure of a cylindrical battery, which comprises a winding core and a core rod arranged in the winding core, the winding core is annular, the winding core comprises the core rod, a positive pole piece and a negative pole piece, the outer surface of the core rod is circular, and two ends of the core rod are provided with ring cuts with the same length; the two ends of the core rod are provided with insulating sleeves matched with the ring cutting. The utility model has the advantages that the strength is high, the stress of the internal pole piece is kept, short circuit or core rod corrosion is avoided, the liquid injection production efficiency of the full-tab battery core is improved, the problem of difficulty in electrolyte infiltration is solved, the infiltration efficiency is high, the assembly difficulty is simplified, the assembly efficiency is improved, and the infiltration effectiveness after liquid injection of the battery core is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a winding structure of a cylindrical battery. Background Art

[0002] A Chinese patent document with a publication date of February 10, 2016 and a publication number of CN205028975U discloses a cylindrical lithium-ion battery winding structure, comprising a pole piece (1), a current collector (2) and a pole ear (3), wherein the pole piece (1) is provided with a current collector (2) on one side, and a pole ear (3) is led out from the current collector (2) through a welding point (4), and the pole piece (1) comprises a positive pole piece and a negative pole piece, and a separator is provided between the positive pole piece and the negative pole piece; the positive pole piece and the negative pole piece are provided with a section of empty foil area in front of the pole ear welding area, and the length of the empty foil area is 0-30 mm; and the number of pre-winding turns of the separator is 0.5-30 turns. Utility Model Content

[0003] The purpose of the utility model is to solve the problem in the prior art that when the winding core is completed, the needle is pulled out during the process, which easily causes the diaphragm at the internal center position to be pulled out along with the winding needle. This causes the entire winding core structure to collapse. After flattening or lamination, the originally designed reserved channel cannot be effectively retained according to the channel shape shown in the figure, thereby failing to effectively achieve the purpose of effective electrolyte infiltration. The processing cost is high, the manufacturing difficulty is large, it is not easy to achieve commercial application, the structure is easy to deform, and during winding, the pole piece and the diaphragm cannot be effectively fitted, which is not conducive to the charging and discharging of the battery. A polygonal structure is adopted, but the support is cylindrical inside, which is not conducive to forming a close fit with the winding needle. At the same time, the outside is polygonal, which will cause the internal pole piece to bend at a certain angle when starting to wind, and there is a risk of the pole piece breaking or the active material falling off. A winding structure for a cylindrical battery is provided, which has the advantages of avoiding the extraction of the diaphragm at the internal center position caused by the needle pulling action, having a certain strength, and maintaining the consistency of the internal pole piece stress.

[0004] The technical solution adopted by the utility model to solve the above technical problems is a winding structure of a cylindrical battery, including a winding core and a core rod arranged in the winding core, the winding core is annular, and the winding core includes the core rod and positive and negative pole pieces. The outer surface of the core rod is circular, and both ends of the core rod are provided with ring cuts of the same length; both ends of the core rod are provided with insulating sleeves matched with the ring cuts. In this way, the utility model solves the existing problems of insufficient strength, high processing cost, high manufacturing difficulty, and the risk of pole piece breakage. It has the advantages of high strength, maintaining internal pole piece stress, avoiding short circuit or core rod corrosion, improving the production efficiency of full-ear battery cell injection, solving the difficulty of electrolyte infiltration, high infiltration efficiency, simplifying assembly difficulty, improving assembly efficiency, and improving the effectiveness of infiltration after battery cell injection.

[0005] Preferably, the winding method of the winding core is from inside to outside.

[0006] Preferably, a plurality of wetting channels are evenly arranged on the surface of the core rod, and the wetting channels are through holes; the wetting channels are located in the middle of the inner surface of the core rod.

[0007] Preferably, the surface of the core rod is passivated and insulated, and the insulating sleeve is made of insulating material.

[0008] Preferably, the insulating sleeve is in a circular ring shape, and the length of the insulating sleeve is the same as the length of the annular cut.

[0009] Preferably, the inner diameter of the insulating sleeve is adapted to the outer diameter of the annular cutting portion of the core rod.

[0010] Preferably, tape is provided on the outside of the positive and negative electrode sheets, and the tape is wound around the

[0011] Preferably, a diaphragm is provided outside the core rod, and the diaphragm is fixed to the core rod after melting.

[0012] The beneficial effect of the utility model is that it solves the existing problems of insufficient strength, high processing cost, great manufacturing difficulty and risk of pole piece breakage. It has the advantages of high strength, maintaining internal pole piece stress, avoiding short circuit or core rod corrosion, improving the production efficiency of full-pole ear battery cell injection, solving the problem of difficult electrolyte infiltration, high infiltration efficiency, simplifying assembly difficulty, improving assembly efficiency, and enhancing the effectiveness of infiltration after battery cell injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a cross-sectional view of a winding core of a cylindrical battery of the utility model;

[0014] Figure 2 It is a cross-sectional view of a core rod of a winding structure of a cylindrical battery of the utility model;

[0015] Figure 3 It is a radial cross-sectional view of a core rod of a cover plate mechanism of a cylindrical battery of the utility model.

[0016] In the figure: 1. core rod, 2. insulating sleeve, 3. wetting channel, 4. winding core, 5. tape, 6. ring cutting. DETAILED DESCRIPTION

[0017] The existing technology has a process of pulling out the needle after the winding of the core is completed, which can easily cause the diaphragm at the internal center position to be pulled out along with the winding needle. The entire core structure collapses. After flattening or lamination, the originally designed reserved channel cannot be effectively retained in the shape of the channel shown in the figure, and thus the purpose of effective electrolyte infiltration cannot be effectively achieved. The processing cost is high, the manufacturing difficulty is large, and it is not easy to achieve commercial application. The structure is easy to deform. During winding, the pole piece and the diaphragm cannot be effectively fitted, which is not conducive to the charging and discharging of the battery. A polygonal structure is adopted, but the interior of the support is cylindrical, which is not conducive to a close fit with the winding needle. At the same time, the outside is polygonal, which will cause the internal pole piece to bend at a certain angle when starting to wind, and there is a risk of pole piece breakage or active material falling off. In order to solve the above problems, the present embodiment is provided.

[0018] The main body of the mandrel described in the utility model is made of common metals, such as any one of steel, iron, copper, aluminum, alloys and composite metal materials. The material must have certain strength and hardness. The outer surface of the mandrel is circular, and the internal cross-section is triangular, quadrilateral or any polygon. As a preferred embodiment, a regular hexagon is used in this embodiment. The polygonal design can match the deformed winding needle, so that the mandrel can be well fixed on the winding needle. When the winding needle is winding, the mandrel will not move or displace, effectively ensuring the smooth winding operation. The inner and outer diameters of the mandrel can be arbitrarily set according to design requirements. At the same time, the surface of the mandrel is designed with holes as a channel for electrolyte infiltration, and the shape of the holes can be set to any geometric shape. At the same time, the number and size of the openings are designed according to the actual size of the mandrel. In this embodiment, as a preferred embodiment, a circular opening method is adopted, and the corresponding position of the opening is located in the middle of the inner surface, and the diameter of the opening is half the length of the inner hexagon. The number of openings is 11 rows, 6 in each row, and a total of 66. Both ends of the core rod are simultaneously cut with a certain length for assembling the insulating sleeve. The surface of the core rod needs to be passivated and insulated, and the surface can be insulated by electroplating, surface treatment or coating with insulating paint. In this embodiment, the surface of the core rod is treated with Teflon coating. In the claims, the comparative document 1 discloses a cylindrical lithium-ion battery winding structure, which relates to a battery winding structure. It includes a pole piece, a current collector and a pole ear. A current collector is provided on one side of the pole piece, and a pole ear is led out of the current collector through a welding point. The pole piece includes a positive pole piece and a negative pole piece, and a diaphragm is provided between the positive pole piece and the negative pole piece. A section of empty foil area is provided in front of the pole ear welding area of ​​the positive pole piece and the negative pole piece. The length of the empty foil area is 0-30mm, and the number of pre-rolled turns of the diaphragm is 0.5-30 turns. After the diaphragm is pre-rolled, the negative pole piece can be pre-rolled first, or the positive pole piece can be pre-rolled first. The number of pre-rolled turns of the positive pole piece and the negative pole piece is 0.5-30 turns. The utility model can effectively and more effectively maintain the amount of electrolyte, and at the same time can improve the utilization rate of existing equipment. The winding needle with a narrow specification range can wind batteries of various specifications, and there is no need to select additional equipment, which saves costs. The most common winding method and structure of cylindrical lithium-ion batteries are disclosed in the specification. The main technical problem solved by this patent is that by increasing the number of turns of the pre-rolled diaphragm, more electrolyte can be stored and absorbed, and the battery cycle life can be improved. At the same time, a winding needle with a smaller diameter can be used to wind large cylindrical batteries. At the same time, the empty foil area at the head of the positive or negative electrode sheet is increased, which is beneficial to the internal heat management of the battery, and improves the battery cycle life and battery safety performance. This patent is a conventional single-pole ear battery cell structure. As the power density of the battery cell increases, this patented structure cannot meet the needs of high-rate discharge of the battery cell.

[0019] The insulating sleeve described in the utility model is made of common insulating materials such as plastic, rubber, and ceramic. The sleeve is in the shape of a circular ring and can be just placed on both ends of the core rod. The outer diameter of the sleeve is consistent with the outer diameter of the core rod. The middle of the sleeve is a through-hole structure, which is convenient for electrolyte injection. Comparative Document 2 discloses a lithium battery core pole piece, a lithium battery core preparation method, and a cylindrical lithium battery in the claims and the specification. The pole piece includes a coating area located in the middle and a foil area located on both sides of the coating area for connecting the pole ears. The edge of the foil area on at least one side is provided with multiple cuts, and the cuts are arranged along the length direction of the pole piece. When the pole piece is wound into a core, multiple cuts overlap on the end face of the core to form a liquid inlet channel, so that the electrolyte can fully infiltrate the positive and negative pole pieces after injection, effectively improving the infiltration effect of the positive and negative pole pieces. This solution achieves the purpose of reserving electrolyte channels by cutting the edge foil area in advance in the electrode processing section. However, in actual operation, the manufacturability is poor because the electrode and the diaphragm have thickness deviations. It cannot be guaranteed that the reserved cuts will present the neat channel form shown in the final figure after winding, and there is a high possibility of misalignment. At the same time, this patent does not introduce the flattening treatment method of the end foil. After flattening, the originally designed reserved channel cannot be effectively retained according to the design shape shown in the figure below.

[0020] The winding core mechanism described in the utility model is composed of the core rod with insulating sleeve, positive and negative electrode sheets, diaphragm and tape as described above. The winding method of the core is to wind the diaphragm, negative electrode, diaphragm and positive electrode from the inside to the outside in this order. The overall length of the core rod with insulating sleeve is flush with the rear end face of the core end collector after the winding is formed. Comparative document 3 discloses a core in the claims and the specification, which has a structure of a stacked body wound in one direction, and the stacked body includes: a first electrode, the first electrode has a first electrode connector of a first polarity; a second electrode, the second electrode has a second electrode connector of a second polarity; and a diaphragm inserted between the first electrode and the second electrode, at least one of the first electrode connector and the second electrode connector has a plurality of slits formed along the winding direction of the core, and the distance between the plurality of slits gradually increases from the core of the core to its periphery. In fact, the idea of ​​the comparative document 2 is quite similar. This patent adopts the method of performing slit punching in the area of ​​the tab foil, and then forming electrolyte channels after winding. The disadvantages of this patent are the same as those of Reference Document 2, namely, poor processability and manufacturability. The original designed channel will be misaligned due to the thickness error of the pole piece and the diaphragm, making it difficult to form a complete channel structure.

[0021] The specific implementation method of the winding core described in the utility model is as follows: first, place the core rod with an insulating sleeve on the winding needle and fix it. Then the winding needle is heated and heated to about 130~150 degrees, and then the diaphragm is melted and fixed on the surface of the core rod, and then it is wound first, and the number of winding turns is generally set to 2~5 turns. Then the negative electrode sheet is wound, and the number of winding turns is generally 2 turns or more, and then the positive electrode sheet is wound. The assembly relationship between the electrode sheets is diaphragm, negative electrode, diaphragm, positive electrode. Finish according to the set length to ensure that the winding relationship of the outermost layer is as follows: the negative electrode sheet completely wraps the positive electrode, and the diaphragm completely wraps the negative electrode. After the terminal diaphragm is cut, it is wrapped and fixed with tape. The size and data of the tape can be set arbitrarily according to the design. In this embodiment, as a preference, the width of the tape is 1 / 8 of the length of the entire winding core, and it is divided into two strips, and the average distance is 1 / 10 of the length of the winding core end face for winding and fixing. After the winding of the core is completed, the current collectors led out from the end face are flattened or laminated to ensure that the processed end face current collectors are consistent with the end faces of the core rod. Comparative Document 4 discloses a cylindrical lithium-ion battery core center needle and battery in the claims and description. The center needle is made of shape memory material. The center needle is hollow or nearly hollow before being inserted into the core. It is a thin strip-shaped alloy rod, which is convenient for inserting into the center hole of the core during the production process. It can effectively avoid the disadvantage of the center needle causing damage to the inside of the core due to excessive diameter during the insertion process. During the heating process of the battery, the center needle will return to a cylindrical structure of a certain diameter, fit tightly with the core, effectively support the inside of the core, and prevent the core from collapsing inward. Although the patent mentions the technical features of the "core rod" in this solution, the process assembly sequence it adopts is significantly different from that of this patent. In this patent, the winding needle is inserted into the core after the core is completed. The "core rod" technical solution cited in this patent is that the core rod is already placed inside the core during winding. After the winding is completed, the winding rod also remains in the winding core structure. At the same time, the design of the "core rod" itself is obviously different, and this patent is obviously a different technical solution compared to this comparative document 4. Comparative document 5 discloses a winding core support for a cylindrical lithium-ion battery in the claims and the specification. The support is a cylindrical spiral spring or a spiral tube composed of spiral wires, and the cylindrical spiral spring or the spiral tube composed of spiral wires is arranged in the winding core hole formed by the pole piece. The support described in the patent can also be regarded as a "core rod". Although the patent mentions the technical features of the "core rod" in this solution, the process assembly sequence adopted is obviously different from that of this patent. In this patent, the winding core support is inserted into the winding core after the winding core is completed. The "core rod" technical solution cited in this patent is that the core rod is already placed inside the winding core during winding. After the winding is completed, the core rod also remains in the winding core structure. At the same time, the design of the "core rod" itself is obviously different, and this patent is obviously a different technical solution compared to this comparative document 5.Comparative Document 6 discloses a winding liner and a long cylindrical battery in the claims and the specification. The winding liner provided by the application forms an internal support for the battery cell by leaving a polygonal cylindrical winding liner inside the wound battery, thereby avoiding the problem of the inner circle of the battery cell being deviated when the needle is pulled out after winding. The winding liner, i.e., the "core rod" itself has obvious design differences, and this patent is obviously a different technical solution compared to Comparative Document 5.

[0022] The innovative features and advantages of this utility model are as follows:

[0023] By placing a core rod with a certain strength inside the core and retaining it in the core, the process of pulling out the needle after conventional core winding is eliminated, and the diaphragm at the center position of the inside is avoided from being pulled out due to the needle pulling action. At the same time, the core rod with a certain strength is conducive to ensuring that the entire core maintains the consistency of the internal pole piece stress during the subsequent charging and discharging process, thereby avoiding the collapse of the entire core structure.

[0024] By performing passivation insulation treatment on the surface of the core rod and adding insulating materials at both ends of the core rod, the insulating materials are installed at both ends of the core rod in the form of sleeves, thereby avoiding the risk of internal short circuit caused by the metal foil at both ends of the core contacting the surface of the core rod during flattening or lamination. Or avoid the core rod from contacting one end of the metal foil at both ends of the core, thereby avoiding the galvanic reaction that occurs. Leading to self-corrosion of the core rod material.

[0025] By designing holes on the surface of the core rod, an infiltration channel for the electrolyte is constructed. When the electrolyte is injected from one end of the core roll, the internal space of the core rod can effectively load the electrolyte. After the injection is completed, the electrolyte penetrates into the internal pole piece of the core roll through the holes in the core rod. It can effectively solve the problems of low production efficiency of full-ear battery injection, difficult internal electrolyte infiltration, and low infiltration efficiency. Compared with patent documents 2&3, the difficulty of battery cell assembly is greatly simplified, the assembly efficiency of the battery cell is effectively improved, and the infiltration effectiveness of the battery cell after injection is effectively improved.

[0026] The beneficial effects of this embodiment are: solving the existing problems of insufficient strength, high processing cost, great manufacturing difficulty, and risk of pole piece breakage, having the advantages of high strength, maintaining internal pole piece stress, avoiding short circuit or core rod corrosion, improving the production efficiency of full-ear battery cell injection, solving the difficulty of electrolyte infiltration, high infiltration efficiency, simplifying assembly difficulty, improving assembly efficiency, and enhancing the effectiveness of infiltration after battery cell injection.

[0027] The above are only preferred embodiments of the present invention and do not constitute any limitation to the present invention. Any simple modification, change and equivalent transformation made to the above embodiments based on the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A winding structure of a cylindrical battery, characterized in that: The invention comprises a winding core and a core rod arranged in the winding core, wherein the winding core is annular and comprises the core rod and positive and negative electrode sheets, the outer surface of the core rod is circular, and annular cut parts of the same length are arranged at both ends of the core rod, and insulating sleeves matching with the annular cut parts of the core rod are arranged at both ends of the core rod.

2. The winding structure of a cylindrical battery according to claim 1, characterized in that: The winding method of the winding core is from inside to outside.

3. The winding structure of a cylindrical battery according to claim 1, characterized in that: A plurality of wetting channels are evenly arranged on the surface of the core rod, the wetting channels are through holes, and the wetting channels are located in the middle of the inner surface of the core rod.

4. The winding structure of a cylindrical battery according to claim 1, characterized in that: The surface of the core rod is passivated and insulated, and the insulating sleeve is made of insulating material.

5. A winding structure of a cylindrical battery according to claim 1 or 4, characterized in that: The insulating sleeve is in a circular ring shape, and the length of the insulating sleeve is the same as the length of the annular cutting portion of the core rod.

6. A winding structure of a cylindrical battery according to claim 1 or 4, characterized in that: The inner diameter of the insulating sleeve is adapted to the outer diameter of the annular cut portion of the core rod.

7. A winding structure of a cylindrical battery according to claim 1, 2 or 4, characterized in that: The insulating sleeve is sleeved on the core rod, and the length of the core rod is flush with the rear end surface of the core end current collector after being flattened after winding.

8. A winding structure of a cylindrical battery according to claim 1 or 2, characterized in that: A diaphragm is also arranged outside the core rod, and the diaphragm is fixed to the core rod after melting.

9. The winding structure of a cylindrical battery according to claim 1, characterized in that: Adhesive tape is arranged on the outer sides of the positive and negative electrode sheets, and the adhesive tape is wound on the diaphragm arranged on the outer periphery of the core rod.

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