Rolling groove inner mold and rolling groove method capable of controlling core compression amount when rolling groove of cylindrical battery shell

Abstract

The present application relates to the field of cylindrical battery shell and rolling groove, in particular to a rolling groove inner mold capable of controlling the winding core compression amount during rolling groove for cylindrical battery shell and a rolling groove method. The present application comprises a cylindrical shaped forming base, a semispherical groove at the bottom, a guide hole in the middle, the guide hole connecting the semispherical groove and the cylindrical cavity; the liftable insulating piece press head bottom is semispherical, the semispherical top is provided with a guide column, the guide column passes through the guide hole, the semisphere is arranged in the semispherical groove, the top of the guide column is provided with a pressure sensor, the middle of the guide column is provided with an inclined rectangular hole transversely penetrating; the guide trajectory cylinder is provided with two opposite parallel inclined surfaces, a guide sliding rod, the guide hole in the middle penetrating the guide column can slide with each other without gap, and the two ends are provided with inclined surfaces in contact with the inclined surfaces of the guide trajectory cylinder. The present application is controlled by the pressing amount of the forming base and the pressing amount of the liftable insulating piece press head respectively, ensures no external invasion amount during the rolling groove process, and avoids the winding core damage caused by large invasion amount of the inner mold end.

Description

Technical Field

[0001] This invention relates to the field of cylindrical battery casings and grooving, specifically to a grooving inner mold and grooving method for cylindrical battery casings that allows control over the compression of the core during grooving. Background Technology

[0002] Lithium-ion cylindrical batteries are currently mainly classified into different systems such as lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, and ternary materials. The casings of cylindrical batteries are available in two types: nickel-plated steel and polymer. Different material systems have different advantages. Currently, nickel-plated steel-cased cylindrical lithium iron phosphate batteries are the most prevalent. Lithium-ion batteries exhibit high capacity, high output voltage, good charge-discharge cycle performance, stable output voltage, high-current discharge capability, electrochemical stability, and safety during use. They will not burn or explode due to overcharging, over-discharging, or short circuits. They also have a wide operating temperature range and are environmentally friendly. They are widely used in energy storage cabinets, solar lighting, backup power, power tools, and globe trucks.

[0003] Cylindrical lithium batteries are widely used as power batteries in electric vehicles. The grooved structure of lithium batteries is particularly important, requiring both safety and high energy density. Therefore, the design of the lithium battery grooved structure is crucial. In the case of a lithium battery steel shell groove, the upper part of the groove supports the cap during sealing, while the lower part of the groove secures the wound core. The lower part of the groove and the wound core typically have a clearance fit. However, this clearance can cause relative movement between the wound core and the steel shell when the cylindrical lithium battery is subjected to high-frequency vibrations. Since the wound core and steel shell are connected by tabs, the relative displacement caused by vibration can lead to breakage of the tabs under high-frequency vibrations, affecting battery reliability.

[0004] Meanwhile, due to the influence of the total height of the lithium battery after sealing, the existing rigid inner mold is compressed downward during the grooving process of the lithium battery steel shell. The compression amount is fixed and needs to leave room for avoidance, which will lead to insufficient utilization of the interior of the lithium battery steel shell. Otherwise, electrode damage will occur during grooving. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a grooving inner mold and grooving method for cylindrical battery casings that allows control over the compression of the core during grooving, thereby solving the problem of excessive compression causing deformation and breakage of the tabs during the grooving process of lithium-ion cylindrical batteries with tabs.

[0006] The present invention provides a grooving inner mold for cylindrical battery casings that allows control over the compression of the winding core during grooving, comprising: The molding base is cylindrical with rounded corners around the bottom. It has a hemispherical groove at the bottom, a guide hole in the middle, and a columnar cavity at the top. The guide hole connects the hemispherical groove and the columnar cavity. The adjustable insulating sheet pressure head has a hemispherical bottom with the flat side facing down. A guide post is provided at the top of the hemisphere, which passes through a guide hole. The hemisphere is placed in a groove in the hemisphere. A pressure sensor is provided at the top of the guide post, and an inclined rectangular hole is provided in the middle of the guide post for horizontal penetration. The guide track cylinder is an inverted cylindrical cavity in the forming base. It has two relatively parallel inclined surfaces inside, a guide sliding rod, and a guide hole that passes through the guide column in the middle. They can slide against each other without gaps. The two ends of the guide sliding rod have inclined surfaces that contact the inclined surfaces of the guide track cylinder.

[0007] According to the cylindrical battery casing, a grooving inner mold that controls the core compression during grooving is provided, and a spring is provided between the guide post and the top surface of the guide track cylinder, with the spring connecting the guide track cylinder and the guide post.

[0008] According to the inner mold for the cylindrical battery casing with controllable core compression during grooving, the lower surface of the hemisphere exposes a hemispherical groove, and an insulating layer is provided on the lower side surface.

[0009] According to the inner mold for the cylindrical battery casing with controllable core compression during grooving, the outer diameter of the forming base is cylindrical and nested and matched with the inner diameter of the lithium battery steel casing to be grooved.

[0010] According to the inner mold for the cylindrical battery casing with controllable core compression during grooving, the outer diameter of the forming base has a flange at the middle position, and the distance from the side of the flange to the lower side of the forming base matches the upper edge distance when the steel casing is grooved.

[0011] According to the cylindrical battery casing, the inner mold for controlling the compression of the core during grooving is used, and the pressure sensor collects the preload of the core in real time during the grooving process.

[0012] The present invention discloses a grooving method for a cylindrical battery casing using a grooving inner mold with controllable core compression during grooving. The method is characterized by comprising the following steps. In the initial stage of grooving: the forming base moves to the inside of the end of the steel shell, the flange abuts against the edge of the steel shell, and the liftable insulating sheet pressure head approaches the inner core; When the guide track cylinder is pulled upward, the inclined surface of the guide sliding rod end acts on the inclined surface of the guide track cylinder. Due to the inclined design of the guide sliding rod and the guide post, the guide sliding rod pushes the guide post of the liftable insulating sheet pressure head downward, squeezing the core and extending the spring. During the period of maximum grooving depth: the forming base continues to press down, the steel shell after grooving continues to compress, the height decreases, the guide track cylinder presses down, the guide sliding rod moves to the right, driving the liftable insulating sheet pressure head to rise, the spring is compressed, the liftable insulating sheet pressure head is raised, ensuring that the compression of the core diaphragm area remains unchanged.

[0013] This invention controls the pressing amount of the forming base and the pressing amount of the liftable insulating sheet pressure head separately, which can collect the pre-tightening force of the core during grooving, while ensuring that there is no external downward intrusion during grooving, thus avoiding damage to the core caused by excessive downward intrusion at the end of the inner mold. Attached Figure Description

[0014] Figure 1 Main view of the inner mold of the grooving (insulating sheet pressure head protruding). Figure 2 Schematic diagram of grooving (initial feed stage) Figure 3 Main view of the inner mold of the groove (insulating sheet pressure head retracted) Figure 4 Grooving diagram (period of maximum feed rate) Figure 5 Schematic diagram of grooving (traditional one-piece grooving inner mold) Figure 6 Schematic diagram of the liftable insulating sheet pressure head (assembly diagram with guide track cylinder) Figure 7 Schematic diagram of the adjustable insulating sheet pressure head (front view) Figure 8 Schematic diagram of the liftable insulating sheet pressure head (left view) In the attached diagram: 1. Spring, 2. Guide track cylinder, 21. Inclined surface, 3. Forming base, 31. Hemispherical groove, 32. Guide hole, 33. Columnar cavity, 4. Guide sliding rod, 41. Inclined surface, 5. Liftable insulating sheet pressure head, 51. Hemisphere, 52. Guide post, 53. Square hole, 6. Roller cutter, 7. Steel shell, 8. Groove intrusion amount, 9. Pressure sensor, 10. Flange. Detailed Implementation

[0015] like Figure 1 The cylindrical battery casing shown is further described in detail using a grooving inner mold and grooving method that allows control over the core compression during grooving. It should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "vertical," "horizontal," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0016] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0017] like Figure 1-5 As shown, the present invention provides a grooving inner mold for controlling the compression of the core during grooving, comprising: a forming base 3, a liftable insulating sheet pressure head 5, and a guide track cylinder 2. Specifically, the forming base 3 is cylindrical with rounded corners around the bottom and a hemispherical groove 31 at the bottom. The outer diameter of the forming base 3 is cylindrical, nesting and matching the inner diameter of the lithium battery steel shell to be grooved. A guide hole 32 is provided in the middle, and a columnar cavity 33 is provided at the top with an opening. The guide hole 32 connects the hemispherical groove 31 and the columnar cavity 33.

[0018] The bottom of the liftable insulating sheet pressure head 5 is a hemisphere 51 made of insulating material, with the flat side facing down. A guide post 52 is provided on the top of the hemisphere 51. The diameter of the guide post 52 is smaller than the diameter of the guide hole 32 and passes upward through the guide hole 32. The hemisphere 51 is set in the hemisphere groove 31. A pressure sensor 9 is provided on the top of the guide post 52, which can collect the pre-tightening force and compression force of the core in real time during the grooving process, quantify the core compression amount, and facilitate the control of the grooving process.

[0019] The guide post 52 has an inclined rectangular hole that runs horizontally through its center. The lower surface of the hemisphere 51 has a hemispherical groove 31 exposed, and an insulating layer is provided on its lower side.

[0020] An inclined guide sliding rod 4 is installed at the central rectangular hole position of the liftable insulating sheet pressure head 5. The guide track cylinder 2 is a cylinder inverted in the cylindrical cavity of the forming base, with two opposing parallel inclined surfaces 21 inside. The guide sliding rod 4 passes through the guide hole 32 of the guide post 52 in the middle, and the two can slide against each other without gap. The two ends of the guide sliding rod 4 have inclined surfaces 41 that contact the inclined surfaces 21 of the guide track cylinder 2. The inclination direction of the guide sliding rod 4 is opposite to the inclination direction of the inclined surfaces 21 of the guide track cylinder 2.

[0021] By raising and lowering the guide track cylinder 2, the inclined surface 21 contacts the inclined surfaces 41 at both ends of the guide sliding rod 4, driving the raising and lowering of the liftable insulating sheet pressure head 5, thus effectively controlling its pressing depth. Figure 1 medium to Figure 2In the process, the inclined surface 21 pushes the guide sliding rod 4 to move to the left. Due to the inclination of the guide sliding rod 4, it slides between itself and the guide post 52, pressing down the guide post 52, and then pressing down the liftable insulating sheet pressure head 5. This allows for separate control of the pressing amount of the forming base 3 and the pressing amount of the liftable insulating sheet pressure head 5 during grooving.

[0022] Furthermore, a spring 1 is provided between the guide post 52 and the top surface inside the guide track cylinder 2, and the spring 1 connects the guide track cylinder 2 and the guide post 52. This is to buffer the force on the guide post 52 when it is pressed down, so as to avoid excessive compression.

[0023] The outer diameter of the forming base 3 has a flange 10 at the middle position. The distance from the side of the flange 10 to the lower side of the forming base 3 matches the upper edge distance left when the steel shell 7 is grooved. The pressure sensor 9 collects the preload of the core in real time during the grooving process.

[0024] During operation, the forming base 3 needs to continuously feed and compress the steel shell 7. After grooving, the steel shell 7 is continuously compressed, and its height decreases. Due to the height limitation of the core, the liftable insulating sheet pressure head 5 cannot be continuously lowered, otherwise it will intrude into the core and cause damage to the core.

[0025] The specific method for using this device to groove steel shells is described below. 1) Initial stage of grooving: The forming base 3 moves to the inside of the end of the steel shell 7, the flange 10 abuts against the edge of the steel shell 7, and the liftable insulating sheet pressure head 5 approaches the inner core. 2) When the guide track cylinder 2 is pulled upward, due to the action of the inclined surface 41 at the end of the guide sliding rod 4 on the inclined surface 21 of the guide track cylinder 2, and due to the inclined design of the guide sliding rod 4 and the guide post 52, the guide sliding rod 4 pushes the guide post 52 of the liftable insulating sheet pressure head 5 downward, squeezing the core and the spring 1 extends. 3) Maximum grooving depth: The forming base 3 continues to press down, the steel shell 7 after grooving continues to compress, the height decreases, the guide track cylinder 2 presses down, the guide sliding rod 4 moves to the right, driving the liftable insulating sheet pressure head 5 to rise, the spring 1 is compressed, the liftable insulating sheet pressure head 5 is raised, ensuring that the compression of the core diaphragm area remains unchanged, avoiding large intrusion that could damage the core.

[0026] In traditional one-piece grooving die design, the intrusion of the lower groove at the end of the die is relatively large during the initial and maximum infeed stages. Figure 5 As stated above.

[0027] The present invention provides an inner mold for controlling the compression of the core during grooving. The compression is controlled by the forming base 3 and the lifting insulating sheet pressure head 5, respectively. The pre-tightening force of the core during grooving can be collected, while ensuring that there is no external intrusion during grooving, thus avoiding damage to the core caused by a large intrusion 8 at the end of the inner mold.

[0028] The above description is merely 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 within the scope of protection of the present invention.

Claims

1. A grooving inner mold for a cylindrical battery casing, characterized in that it allows for controllable core compression during grooving. include: The molding base (3) is cylindrical with rounded corners around the bottom. It has a hemispherical groove (31) at the bottom, a guide hole (32) in the middle, and a columnar cavity (33) at the top. The guide hole (32) connects the hemispherical groove (31) and the columnar cavity (33). The adjustable insulating sheet pressure head (5) has a hemisphere (51) at the bottom with the flat side facing down. A guide post (52) is provided at the top of the hemisphere (51). The guide post (52) passes through the guide hole (32). The hemisphere (51) is set in the hemisphere groove (31). An inclined rectangular hole is provided in the middle of the guide post (52) and passes through it laterally. The guide track cylinder (2) is an inverted cylindrical cavity in the molding base. It has two parallel inclined surfaces (21) inside. The guide sliding rod (4) passes through the rectangular hole of the guide column (52) and can slide against each other. The guide sliding rod (4) has inclined surfaces (41) at both ends that contact the inclined surfaces (21) of the guide track cylinder (2).

2. The grooving inner mold for cylindrical battery casing with controllable core compression during grooving, as described in claim 1, is characterized in that... A spring (1) is provided between the guide column (52) and the top surface inside the guide track cylinder (2). The spring (1) connects the guide track cylinder (2) and the guide column (52). A pressure sensor (9) is provided on the top of the guide column (52).

3. The inner mold for controlling the core compression during grooving of a cylindrical battery casing according to claim 1, characterized in that, The lower surface of the hemisphere (51) exposes a hemispherical groove (31), and an insulating layer is provided on the lower side surface.

4. The grooving inner mold for cylindrical battery casing with controllable core compression during grooving, as described in claim 1, is characterized in that... The outer diameter of the molding base (3) is cylindrical, which is nested and matched with the inner diameter of the lithium battery steel shell to be grooved.

5. The grooving inner mold for cylindrical battery casing with controllable core compression during grooving as described in claim 2, characterized in that, during molding... The outer diameter of the base (3) has a flange (10) in the middle position. The distance from the side of the flange (10) to the lower side of the molded base (3) matches the upper edge distance when the steel shell (7) is grooved.

6. The grooving inner mold for cylindrical battery casing with controllable core compression during grooving, as described in claim 2, is characterized in that... The pressure sensor (9) collects the preload of the core during the grooving process in real time.

7. A grooving method for a grooving inner mold with controllable core compression during grooving of a cylindrical battery casing as described in claim 5, characterized in that, Includes the following steps, 1) Initial stage of grooving: The forming base (3) moves to the inside of the end of the steel shell (7), the flange (10) abuts against the edge of the steel shell (7), and the liftable insulating sheet pressure head (5) approaches the inner core; 2) When the guide track cylinder (2) is pulled upward, due to the action of the inclined surface (41) at the end of the guide sliding rod (4) on the inclined surface (21) of the guide track cylinder (2), and due to the inclined design of the guide sliding rod (4) and the guide post (52), the guide sliding rod (4) pushes the guide post (52) of the liftable insulating sheet pressure head (5) downward, squeezing the core, and the spring (1) extends; 3) The period of maximum grooving depth: The forming base (3) continues to press down, the steel shell (7) after grooving continues to compress, the height decreases, the guide track cylinder (2) presses down, the guide sliding rod (4) moves to the right, driving the liftable insulating sheet pressure head (5) to rise, the spring (1) is compressed, the liftable insulating sheet pressure head (5) is raised, ensuring that the compression of the core diaphragm area remains unchanged.

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