Connector and battery

Abstract

A connecting element (1) characterized in that it comprises: a body part (11); and a connecting part (12); wherein the connecting part (12) is connected to an edge of the body part (11) in a circumferential direction; the connecting part (12) is bendable with respect to the body part (11) to form an angle between the connecting part (12) and the body part (11); a through hole (14) is defined on a section line (13) between the connecting part (12) and the body part (11).

Description

This application claims priority from Chinese Patent Application No. 202221146211.2 filed with the Chinese Patent Office on May 12, 2022, the entire contents of which are incorporated by reference into this application. Technical area The present application relates to the field of power battery technology, and more particularly to a connector and a battery. State of the art Power batteries are widely used in new energy pure electric vehicles and new energy hybrid vehicles. Due to the market demand for long battery life, the research and development focus of major battery manufacturers has shifted to high-energy-density batteries. It is understood that the higher the energy density of the power battery, the lower the safety of the power battery. Therefore, improving the safety of the power battery is a top priority. One end of the connector of a cylindrical lithium-ion battery is laser-welded to one side of the wound core with electrode strips to collect the current, and the other end of the connector is welded to a side wall of the case to dissipate the current. A commonly used method in related technology is to weld the connector to the side wall and then seal the openings. To increase battery capacity, it is necessary to ensure the space utilization within the case. Generally, the side wall is overlapped with the floor plane by a rolling groove gasket. However, during the grooving process, the connector bends. Since the curved contour of the connector is a curve, the internal stress generated by the bending causes the edge of the connector to deform and sink sharply when the end welded to the side wall of the case bends inward. This causes the connector to insert into the winding core, resulting in lithium precipitation in mild cases and safety hazards in severe cases. Contents of this application The present application discloses a fastener and a battery to prevent the edge from sinking into the core during roll groove sealing, thereby reducing safety risks and improving safety. The present application provides a fastener comprising: a body part; and a connecting part; wherein the connecting part is connected to an edge of the body part in a circumferential direction; the connecting part is bendable with respect to the body part to form an angle between the connecting part and the body part; a through hole is defined on an intersection line between the connecting part and the body part. In some embodiments, the cutting line is an arc centered on the middle of the body part, and a central angle α of the arc is in the range of 30° to 60°. In some embodiments, the through-hole is an elongated circular hole, and the longitudinal axis of the elongated circular hole is perpendicular to the intersection line when an angle between the connecting part and the body part is 180°. In some embodiments, the through hole is one of a diamond-shaped hole, a rectangular hole, or a circular hole when an angle between the connecting part and the body part is 180°. In some embodiments, the connecting member comprises a plurality of connecting members arranged at intervals circumferentially of the body member; wherein an escape slot is arranged between every two adjacent connecting members on one side of the body member in the circumferential direction. In some embodiments, the cutting line comprises a plurality of cutting lines, and each of the plurality of cutting lines is disposed between a corresponding connecting part and the body part; wherein the plurality of cutting lines are disposed on a same circumference. In some embodiments, a groove is arranged on one side of the connecting element in the circumferential direction at each of the two ends of the cutting line. In some embodiments, the body part is provided with a plurality of fluid leak holes. In some embodiments, the through-hole comprises a plurality of through-holes arranged at intervals along the longitudinal direction of the cutting line. The present application further discloses a battery comprising: a case, a cell bobbin disposed in the case, and the connecting member upward; wherein the case is provided with a circumferentially recessed through groove; the body part is electrically connected to an electrode at one end of the cell bobbin, and the connecting part is electrically connected to an inner surface of the through groove. In summary, the present application offers the following technical effects: The present application discloses a connector and a battery. The body portion of the connector is used to connect to the electrode strips of the winding core. The connector is used to connect to the housing. When the housing undergoes a roll groove seal, the connector begins to rotate with the housing relative to the body portion. The through hole at the intersection line reduces the strength of the connector at the intersection line, resulting in less internal stress during the connector's inward rotation toward the housing portion.The generated internal stress can be released by the deformation of the through hole, thereby greatly reducing the extent of sinking of the edge of the fastener, preventing the edge of the fastener from inserting into the winding core during the rolling groove seal, thereby reducing safety risks. Short description of the drawing Fig. 1 is a structural view of a folded connecting part of a connecting element according to an embodiment of the present application. Fig. 2 is a plan view of a folded connecting part of a connecting element according to an embodiment of the present application. Fig. 3 is a plan view of an unfolded connecting part of a connecting element according to an embodiment of the present application. Fig. 4 is a partial cross-sectional view of a battery according to an embodiment of the present application. In the drawings: 1: connecting element; 2: casing; 3: cell winding body; 11: body part; 12: connecting part; 13: cutting line; 14: through hole; 15: groove; 16: liquid leakage hole; 21: through groove; 111: escape slot. Detailed description of the embodiments In the description of this application, it should be noted that the terms "center," "top," "bottom," "left," "right," "vertical," "horizontal," "inside," "outside," and other terms indicating a direction or positional relationship are based on the directions or positional relationships shown in the drawings and are used to simplify the description of this application and to simplify the description. They are not intended to indicate or imply that the device or element in question must be constructed and operated in a particular direction or position, and therefore should not be construed as limitations of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.The terms “first position” and “second position” refer to two different positions. Unless expressly stated and limited otherwise, the terms "installed," "connected," "coupled," and "attached" are to be understood in a broad sense, meaning they may refer to a fixed or detachable connection, a mechanical or electrical connection, a direct or indirect connection via an intermediate medium, a connection of the interior of two elements, or an interaction between two elements. A person skilled in the art may understand the specific meaning of the above terms in the present application depending on the specific context. Unless expressly stated and limited otherwise, a first feature located "on top of" or "below" a second feature can include the first feature and the second feature in direct contact, or the first feature and the second feature not in direct contact but in contact through another feature between them. Furthermore, the first feature located "on top of," "at the top of," and "over" the second feature(s) includes the first feature directly above and diagonally above the second feature, or simply indicates that the first feature is horizontally higher than the second feature. The first feature located "below," "below," and "at the bottom of" the second feature(s) includes the first feature directly below and diagonally below the second feature, or simply indicates that the first feature is horizontally lower than the second feature. The present application is described below in conjunction with the accompanying drawings and with reference to specific embodiments. With the development of the new energy vehicle market, improving the energy density of power batteries has become a priority for battery manufacturers' research and development. High energy density inevitably entails high risk, so improving the safety of power batteries has become a top priority. A cylindrical lithium-ion battery comprises a connecting element 1. The connecting element 1 is connected to the cell electrode strips or the housing, respectively, connecting the battery housing to the positive electrode or the negative electrode of the cell. To increase battery capacity, space utilization within the housing 2 must be ensured. Generally, the side wall of the housing overlaps with the bottom plane of the housing through a rolled groove seal. However, during the grooving process, the connector bends. Since the curved contour of the connector is a curve, the internal stress generated by the bending causes the edge of the connector to deform and sink significantly when the end of the connector welded to the side wall of the case bends inward. This causes the connector to be inserted into the winding core, resulting in lithium precipitation or direct damage to the separator, and ultimately leading to safety accidents due to contact between the positive and negative electrodes, resulting in a short circuit. To solve the above-mentioned problem, this embodiment provides a connecting member 1. As shown in Figs. 1 to 3, the connecting member 1 comprises a body part 11 and a connecting part 12; wherein the connecting part 12 is connected to an edge of the body part 11 in a circumferential direction; the connecting part 12 is bendable with respect to the body part 11 to form an angle between the connecting part 12 and the body part 11, and a through hole 14 is defined on an intersection line 13 between the connecting part 12 and the body part 11. The body part 11 of the connector 1 is used to connect to the electrode strips of the winding core. The connector 12 is used to connect to the housing 2. When the housing 2 undergoes roll groove sealing, the connector 12 begins to rotate with the housing 2 relative to the body part 11. The through hole 14 at the intersection line 13 reduces the strength of the connector 12 at the intersection line 13, resulting in less internal stress during the connector 12's inward rotation toward the housing part 11. The generated internal stress can be released by the deformation of the through hole 13, thereby greatly reducing the amount of sinking of the edge of the connector 1, which prevents the edge of the connector 1 from inserting into the winding core during roll groove sealing, thereby reducing safety risks. For example, as shown in Fig. 3, the cutting line 13 is an arc centered on the center of the body part 11, and a central angle α of the arc is in the range of 30° to 60°. The central angle α corresponds to the length of the cutting line 13, among which the length of the cutting line 13 should not be too long and not too short. If the length of the cutting line 13 is too long, the welding area of the connecting part 12 and the housing 2 is relatively large, which is easy to lead to poor welding. In addition, if the length of the cutting line 13 is too long, the internal stress generated during the rotation of the connecting part 12 relative to the body part 11 is relatively large and not easy to release. If the length of the cutting line 13 is too short, the connecting part 12 and the housing 2 are prone to poor welding and breakage. For example, the central angle α corresponding to the section line 13 can be 35°, 40°, 45°, 50°, 55°. By way of example, as shown in Fig. 3, the through-hole 14 is an elongated circular hole, wherein the longitudinal axis of the elongated circular hole is perpendicular to the intersection line 13 when an angle between the connecting part 12 and the body part 11 is 180°. The longitudinal axis of the elongated circular hole is perpendicular to the intersection line 13, i.e., the straight part of the elongated circular hole is almost perpendicular to the intersection line 13. During bending of the connecting part 12 toward the body part 11, the straight part of the elongated circular hole has sufficient deformation margin to largely prevent twisting of the connecting element 1 and thus protect a separator from damage. By way of example, the through-hole 14 is any hole, which can be a diamond-shaped hole, a rectangular hole, or a circular hole if an angle between the connecting part 12 and the body part 11 is 180°. If the through-hole 14 is a diamond-shaped hole, a diagonal of the diamond-shaped hole is perpendicular to the section line 13. If the through-hole 14 is a rectangular hole, a set of opposite side edges of the rectangular hole is perpendicular to the section line 13. For example, as shown in Fig. 1 and Fig. 3, a plurality of connecting parts 12 are arranged at intervals in the circumferential direction of the body part 11. An escape slit 111 is arranged between every two adjacent connecting parts 12 on one side of the body part 11 in the circumferential direction. The plurality of connecting parts 12 are each welded to the casing 2 to establish an electrical connection, which can reduce the internal resistance of the battery on the one hand and ensure the connection strength between the connecting member 1 and the casing 2 on the other. The arrangement of the escape slit 111 also prevents the connecting member 1 from being deformed due to the problem of processing accuracy caused by the interference between the parts other than the connecting part 12 and the casing 2, which may lead to damage to the separator, thereby improving the safety of the battery. By way of example, several of the cut lines 13 are located on the same circumference. Since the housing 2 is cylindrical, the provision of several cut lines 13 on the same circumference allows all connecting parts 12 to fit tightly against the housing 2, which facilitates welding and also increases strength. When the housing 2 is subjected to the roll groove seal, the deformation remains uniform along each cut line 13. For example, as shown in Figs. 1 to 3, a groove 15 is provided on one side of the connecting member 1 in the circumferential direction at each of the two ends of the cutting line 13. For example, the groove 15 is partially provided on the connecting part 12 and partially on the body part 11. The groove 15 can further provide a dissipation site for the internal stress generated during rotation of the connecting part 12 relative to the body part 11, and further prevent the two ends of the cutting line 13 from crossing the outer contour of the connecting member 1 and interfering with the casing 2, which may cause sinking, thereby significantly reducing the degree of deformation of the connecting member 1 and improving the safety of the battery. For example, the body part 11 is provided with several fluid leak holes 16. After the battery is sealed, an electrolyte must be injected into the battery through a fluid injection hole. After the electrolyte has flowed into the connecting element 1, the electrolyte should be able to flow through the fluid leak holes 16 into a cell winding former 3. For example, a plurality of through-holes 14 are arranged at intervals along the length of the cutting line 13. The plurality of through-holes 14 can significantly reduce the strength at the cutting line 13, thereby reducing the internal stress generated during rotation of the connecting part 12 relative to the body part 11, and can further provide a deformation margin for releasing the internal stress to prevent the edge of the connecting element 1 from sinking. The connecting element 1, for example, is formed in one piece. The connecting element 1 is integrally formed by punching the raw material sheet, which provides excellent productivity and high dimensional accuracy. The present embodiment further provides a battery as shown in Fig. 4; the battery comprising a case 2, a cell bobbin 3 arranged in the case 2, and a connecting member 1; the case 2 is provided with a circumferentially recessed through groove 21; the body part 11 is electrically connected to an electrode at one end of the cell bobbin 3, and the connecting part 12 is electrically connected to an inner surface of the through groove 21. This battery includes the above-mentioned connecting member 1. When the casing 2 is subjected to rolling groove sealing, the through hole 14 on the intersection line 13 between the connecting part 12 and the casing part 11 can release the internal stress by deformation, thereby preventing the edge of the connecting member 1 from sinking into the cell bobbin 3 and damaging the separator, which greatly improves the safety of the battery. QUOTES CONTAINED IN THE DESCRIPTION This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature CN 202221146211.2

[0001]

Claims

A connecting element (1), characterized in that it comprises: a body part (11); and a connecting part (12); wherein the connecting part (12) is connected to an edge of the body part (11) in a circumferential direction; the connecting part (12) is bendable with respect to the body part (11) to form an angle between the connecting part (12) and the body part (11); a through hole (14) is defined on an intersection line (13) between the connecting part (12) and the body part (11). Connecting element (1) according to claim 1, wherein the cutting line (13) is an arc centered on the center of the body part (11), and a central angle α of the arc is in the range of 30° to 60°. Connecting element (1) according to claim 1, wherein the through hole (14) is an elongated circular hole, and the longitudinal axis of the elongated circular hole is perpendicular to the cutting line (13) when an angle between the connecting part (12) and the body part (11) is 180°. Connecting element (1) according to claim 1, wherein the through hole (14) is one of a diamond-shaped hole, a rectangular hole, or a circular hole when an angle between the connecting part (12) and the body part (11) is 180°. Connecting element (1) according to one of claims 1 to 4, wherein the connecting part (12) comprises a plurality of connecting parts (12) arranged at intervals in the circumferential direction of the body part (11); an escape slot (111) is arranged between every two adjacent connecting parts (12) on one side of the body part (11) in the circumferential direction. Connecting element (1) according to claim 5, wherein the cutting line (13) comprises a plurality of cutting lines (13), and each of the plurality of cutting lines (13) is arranged between a corresponding connecting part (12) and the body part (11); the plurality of cutting lines (13) are arranged on a same circumference. Connecting element (1) according to one of claims 1 to 4, wherein a groove (15) is arranged on one side of the connecting element (1) in the circumferential direction at each of the two ends of the cutting line (13). Connecting element (1) according to one of claims 1 to 4, wherein the body part (11) is provided with a plurality of liquid leakage holes (16). Connecting element (1) according to one of claims 1 to 4, wherein the through-hole (14) comprises a plurality of through-holes (14) arranged at intervals along the longitudinal direction of the cutting line (13). A battery comprising: a casing (2), a cell winding body (3) arranged in the casing (2), and the connecting element (1) according to one of claims 1 to 9; wherein the casing (2) is provided with a circumferentially recessed through groove (21); the body part (11) is electrically connected to an electrode at one end of the cell winding body (3), and the connecting part (12) is electrically connected to an inner surface of the through groove (21).

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