Battery ptc connection structure

Abstract

The utility model discloses a battery PTC connecting structure relates to lithium subcylindrical battery technical field, include: plastic cover, the plastic cover sets up at battery shell top and is provided with the open installation circular groove, is equipped with the through -hole for the electric core to pass through upwards on the installation circular groove, metal positioning sheet, the metal positioning sheet sets up in the installation circular groove and is connected with the electric core, PTC thermistor, the PTC thermistor is circular and is connected on the top of metal positioning sheet in the installation circular groove, metal false cover, the metal false cover sets up in the installation circular groove and bottom surface is connected with PTC thermistor, be equipped with the anti -rotation spare for limiting metal positioning sheet, metal false cover rotation in the installation circular groove. The utility model discloses through the structure innovation, makes the false cover surface keep level while keeping the PTC protection function, and all parts vertical stacking connection makes the PTC response fast, especially applicable to the security protection demand of miniaturization, high energy density battery.

Description

Technical Field

[0001] This utility model relates to lithium-ion cylindrical batteries, specifically a small-diameter battery PTC connection structure. Background Technology

[0002] PTC thermistors are special materials whose resistance increases with temperature, making them indispensable for battery safety protection. Traditional resistors typically exhibit a stable resistance when current flows through them, while PTC resistors show an increase in resistance with temperature. When a battery or battery pack experiences overcurrent or overheating, the resistance of the PTC material increases dramatically, thus limiting the current and preventing safety issues caused by overcurrent or overheating.

[0003] In existing high-power battery internal thermistor and metal dummy cover connection structures, two nickel strips are used to connect the bottom surface of the semi-circular PTC thermistor to the battery cell and the top surface of the thermistor end to the dummy cover, respectively. However, this connection method has the following drawbacks:

[0004] 1. This is only applicable to high-power batteries with a large diameter (≥33mm). Two nickel strips connect the top and bottom surfaces of the PTC thermistor respectively. This requires that the two nickel strips under the dummy cover have a certain safety gap in the radial direction. Moreover, the dummy cover needs to have enough radial space outside the opening for the nickel strips to pass through and then be folded outwards for welding. Otherwise, insufficient welding space will result in the nickel strips not being firmly connected to the dummy cover. However, the radial space of small-diameter batteries is limited. Therefore, the existing structure is difficult to apply to high-power batteries with a small diameter (≤20mm).

[0005] 2. The surface of the counterfeit cap is uneven, and the nickel strip connected to the counterfeit cap needs to be threaded through the surface of the counterfeit cap. The nickel strip is partially exposed on the counterfeit cap, which causes the nickel strip to bend and puncture the trademark, thus affecting the safety performance.

[0006] Therefore, it is necessary to develop a PTC connection structure that is simple in structure, easy to install, suitable for small-diameter high-power batteries, and has a flat top. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide a PTC connection structure that is simple in structure, easy to install, suitable for small-diameter high-power batteries, and has a flat top.

[0008] The technical solution of this utility model is: a battery PTC connection structure, characterized in that it includes:

[0009] A plastic cover is provided on the top of the battery casing and has an open mounting groove. The mounting groove has a through hole through which the power supply core passes upward.

[0010] A metal positioning piece, wherein the metal positioning piece is disposed in the mounting groove and connected to the battery cell;

[0011] The PTC thermistor is ring-shaped and connected above the metal positioning plate within the mounting groove.

[0012] A metal dummy cover is disposed in a mounting groove and its bottom surface is connected to a PTC thermistor. The mounting groove is provided with an anti-rotation component to limit the rotation of the metal positioning piece and the metal dummy cover.

[0013] Preferably, the anti-rotation component includes an anti-rotation protrusion with the wall of the mounting groove facing inward, and anti-rotation notches corresponding to the anti-rotation protrusion are provided on the outer edge of the metal positioning piece and the metal false cover.

[0014] Furthermore, the through hole is located at the center of the mounting groove, and a hollow boss is formed on the metal positioning piece. The hollow boss and the through hole are vertically aligned for welding the battery cell into the hollow boss.

[0015] Furthermore, the inner ring of the PTC thermistor passes through the hollow boss, and the PTC thermistor is directly welded to the upper surface of the metal positioning plate or welded to the upper surface of the metal positioning plate through a metal connecting piece.

[0016] Furthermore, the metal connecting piece is an annular structure with the inner ring passing through the hollow boss. The metal connecting piece has an edge notch corresponding to the anti-rotation protrusion. The metal dummy cover, PTC thermistor, and metal connecting piece are connected as a whole by hot melt soldering.

[0017] Furthermore, the outer diameter of the metal dummy cover, the outer diameter of the metal connecting piece, and the outer diameter of the metal positioning piece all correspond to the inner diameter of the mounting groove. The outer diameter of the PTC thermistor is smaller than the outer diameter of the metal connecting piece, and the inner diameter is larger than the inner diameter of the metal connecting piece. The metal connecting piece has a spot welding area at the outer edge of the PTC thermistor.

[0018] Furthermore, the metal connecting piece is resistance-welded to the metal positioning piece through a spot welding area, and the metal dummy cover is provided with an avoidance notch corresponding to the spot welding area.

[0019] Furthermore, the two spot welding areas are radially symmetrically arranged on the metal connecting piece.

[0020] Furthermore, the metal dummy cap has an upward convex shape at the center of its top, forming a dummy cap convex cap corresponding to the hollow convex platform.

[0021] Preferably, the bottom surface of the plastic cover is provided with a groove for accommodating the battery cell sealing nail, and the groove is annular and coaxial with the plastic cover.

[0022] The beneficial effects of this utility model are as follows:

[0023] 1. The connection between the PTC thermistor and the battery cell, and between the thermistor and the dummy cover, is achieved by using metal positioning pieces. There is no need to set nickel strips to pass through the metal dummy cover. This makes the final installed battery metal cover plate and the metal dummy cover flat and seamless. After inserting the trademark sleeve and heat shrinking it, the appearance meets the requirements and there will be no sharp edges exposed due to one side lifting up.

[0024] 2. The plastic cover is equipped with an anti-rotation component to restrict the rotation between the metal positioning plate and the metal dummy cover. This restricts the PTC thermistor located between the metal positioning plate and the metal dummy cover from rotating around the positive electrode core of the battery cell. This prevents the edge of the metal dummy cover from rotating and puncturing the plastic trademark sleeve, which would cause a short circuit and greatly improves the safety performance of the battery.

[0025] 3. No complex nickel bar structure is required, and there is no need for drilling and welding on the metal dummy cover. Radially, there is no need to leave a safety space for the two nickel bars, and the dummy cover does not require pre-reserved welding space outside the opening. The structure is simple and easy to use. All parts of this invention are stacked vertically, with no additional components in the radial direction. It is particularly effective in high-power batteries with small diameters (≤20mm). The cell-positioning plate-PTC-dummy cover form a vertical heat conduction path, and the PTC has a rapid thermal response, which can improve the sensitivity of overcurrent protection.

[0026] 4. A hollow boss is set at the center of the metal positioning plate and connected to the battery cell by resistance welding. Compared with nickel bar welding, the hollow boss is more conducive to the positioning and fixing of the battery cell and improves the stability of the overall structure.

[0027] 5. Considering existing welding processes, the temperature sensing element inside the PTC thermistor should be soldered using hot melt soldering as much as possible. Compared to hot melt soldering, resistance spot welding has the advantages of automation, speed, and no need for additional materials. If resistance spot welding is used directly, the temperature sensing element can easily be damaged during the voltage-down process. Therefore, if the PTC thermistor is soldered using hot melt soldering, it can be directly welded to the metal positioning piece; if resistance spot welding is used, it can be achieved through a metal connecting piece, adapting to various production processes.

[0028] 6. When connecting PTC thermistors through metal connecting pieces, the metal connecting pieces, PTC, and metal dummy cap are pre-formed into a whole by hot melt soldering the upper and lower surfaces of the PTC. Then, the PTC connection structure can be quickly installed by resistive spot welding the metal connecting pieces to the positioning pieces.

[0029] 7. The metal connecting piece has a spot welding area extending beyond the outer edge of the PTC thermistor. Spot welding avoids contact with the PTC thermistor, preventing adverse effects and ensuring its thermal response performance. An edge notch on the metal connecting piece mates with the mounting groove of the plastic cover to prevent rotation and ensure installation stability.

[0030] 8. The radially symmetrical layout of the double spot welding area ensures balanced stress on the metal connecting pieces and guarantees the long-term reliability of the PTC module.

[0031] 9. The groove design at the bottom of the plastic cover is compatible with existing cell sealing structures, the coaxial layout avoids affecting the central conductive path, and the integrated design reduces the number of parts.

[0032] This invention, through structural innovation, maintains the PTC protection function while ensuring the surface of the dummy cover remains flat without any additional components. All parts are vertically stacked and connected, enabling the PTC to respond quickly. It is particularly suitable for the safety protection needs of miniaturized, high-energy-density batteries. Attached Figure Description

[0033] Figure 1 This is a part drawing of the present utility model.

[0034] Figure 2 This is a part drawing of the present utility model (the battery casing is omitted).

[0035] Figure 3 This is a schematic diagram of the assembled structure of this utility model.

[0036] Figure 4 Top view of PTC thermistor and metal connecting piece connection

[0037] Figure 5 Top view of the present invention after assembly

[0038] Figure 6 for Figure 4 AA section diagram

[0039] Wherein: 1-Plastic cover 2-Metal positioning piece 3-Metal connecting piece 4-PTC thermistor 5-Metal false cover 6-Anti-rotation notch 10-Battery casing 20-Battery cell;

[0040] 11-Installation groove; 12-Through hole; 13-Anti-rotation protrusion; 14-Groove.

[0041] 21-Hollow boss; 31-Edge notch; 32-Spot welding area; 51-Avoidance notch; 52-False cap. Detailed Implementation

[0042] The embodiments of this utility model are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0043] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to 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 this utility model.

[0044] 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0045] like Figure 1-6 As shown, this utility model provides a PTC connection structure for small-diameter, high-power batteries, including a plastic cover 1 with an installation groove 11, and a metal positioning piece 2, a PTC thermistor 4, and a metal dummy cover 5 stacked in the installation groove 11 from bottom to top. As a preferred example, the plastic cover 1, the installation groove 11, the metal positioning piece 2, the PTC thermistor 4, and the metal dummy cover 5 are all coaxially arranged with the cylindrical battery casing 10, and the battery cell 20 (positive electrode cell) is arranged at the central axis of the battery casing 10.

[0046] A plastic cover 1 is located on the top of the battery casing 10 and has an open mounting groove 11. A through hole 12 is provided on the mounting groove 11 through which the power supply core 20 passes upward. The bottom surface of the plastic cover 1 has a groove 14 for accommodating the battery cell sealing pin. The groove 14 is annular and coaxial with the plastic cover 1.

[0047] A metal positioning piece 2 is disposed within the mounting groove 11 and connected to the battery cell 20. A hollow boss 21 is formed by an upward protrusion at the center of the metal positioning piece 2. The hollow boss 21 and the through hole 12 are vertically aligned for welding the battery cell 20 into the hollow boss 21. As a preferred embodiment, the battery cell 20 and the hollow boss 21 are welded together by resistance spot welding. Resistance spot welding has the advantages of automation, speed, and no need for additional materials, making it suitable for small-diameter batteries operating in confined spaces.

[0048] The PTC thermistor 4 is ring-shaped and connected above the metal positioning plate 2 within the mounting groove 11. The PTC thermistor 4 is directly welded to the upper surface of the metal positioning plate 2 or welded to the upper surface of the metal positioning plate 2 through the metal connecting piece 3.

[0049] The metal dummy cover 5 is disposed within the mounting groove 11 and its bottom surface is connected to the PTC thermistor 4. The mounting groove 11 is provided with an anti-rotation component to limit the rotation of the metal positioning piece 2 and the metal dummy cover 5. As a preferred example, the anti-rotation component is an anti-rotation protrusion 13 provided inward on the groove wall of the mounting groove 11, and the outer edges of the metal positioning piece 2 and the metal dummy cover 5 are provided with anti-rotation notches 6 corresponding to the anti-rotation protrusion 13.

[0050] Considering existing welding processes, the temperature sensing element inside the PTC thermistor 4 is connected to other components primarily via hot-melt soldering. Compared to hot-melt soldering, resistance spot welding offers advantages such as automation, speed, and the elimination of the need for additional materials. However, direct resistance spot welding can easily damage the temperature sensing element of the PTC thermistor 4 during the voltage-down process. Therefore, the PTC thermistor 4 can be directly soldered to the metal positioning plate 2 via hot-melt soldering, or resistance spot welded to the metal positioning plate 2 via the metal connecting piece 3.

[0051] As one example, the PTC thermistor 4 is directly soldered to the metal positioning piece 2 using hot melt soldering. The hollow boss 21 of the metal positioning piece 2 passes through the inner ring of the PTC thermistor 4. The metal dummy cover 5 is hot melt soldered to the upper surface of the PTC thermistor 4. The top center of the metal dummy cover 5 protrudes upward to form a dummy cover convex cap 52 corresponding to the hollow boss 21. The outer diameters of the metal positioning piece 2 and the metal dummy cover 5 correspond to the diameter of the mounting groove 11. The outer diameter of the PTC thermistor 4 is smaller than the outer diameters of the metal positioning piece 2 and the metal dummy cover 5, while its inner diameter is larger than the outer diameter of the hollow boss 21. Therefore, when the PTC thermistor 4 is sandwiched between the metal positioning piece 2 and the metal dummy cover 5, its inner and outer edges do not contact other parts, forming a protective gap to avoid collision damage and maintain the long-term reliability of the PTC thermistor 4.

[0052] At this point, the battery cell 20, metal positioning piece 2, PTC thermistor 4, and metal dummy cover 5 form a vertical heat conduction path from bottom to top. The PTC thermistor 4 has a rapid thermal response, which can improve the sensitivity of overcurrent protection.

[0053] The working principle of this example is as follows: Within the mounting groove 11 of the plastic cover 1, the metal positioning piece 2 fits against the bottom of the groove 11 and is spot-welded to the battery cell 20 via the hollow boss 21. Then, the PTC thermistor 4 and the metal dummy cover 5 are sequentially installed using hot-melt soldering, completing the installation of the top structure of the battery casing 10. When excessive current is generated within the battery cell, resulting in significant heat, the heat is vertically conducted to the PTC thermistor 4 via the metal positioning piece 2, thus providing overheat protection for the battery.

[0054] As another example, the PTC thermistor 4 is spot-welded to the metal positioning piece 2 via a metal connecting piece 3. The specific structure of the metal connecting piece 3 is as follows: it is an annular ring coaxially arranged with the battery casing 10, and the metal connecting piece 3 has an edge notch 31 and an anti-rotation protrusion 13 for anti-rotation purposes. The outer diameter of the metal connecting piece 3 corresponds to the diameter of the mounting groove 11. The outer diameter of the PTC thermistor 4 is smaller than the outer diameter of the metal connecting piece 3, and the inner diameter is larger than the inner diameter of the metal connecting piece 3 (e.g., ...). Figure 4 As shown, when the PTC thermistor 4 is sandwiched between the metal connecting piece 3 and the metal dummy cover 5, its inner and outer edges do not contact other parts, forming a protective gap to avoid collision damage, thereby maintaining the long-term reliability of the PTC thermistor 4. The metal connecting piece 3 has a spot welding area 32 at the outer edge of the PTC thermistor 4. As a preferred example, two spot welding areas 32 are radially symmetrically arranged on the metal connecting piece 3, and the metal dummy cover 5 has an avoidance notch 51 corresponding to the spot welding area 32.

[0055] During installation, the hollow protrusion 21 of the metal positioning piece 2 passes through the inner ring of the metal connecting piece 3 and the inner ring of the PTC thermistor 4. The metal connecting piece 3, the PTC thermistor 4, and the metal dummy cover 5 are pre-connected as a whole on the outside of the battery casing 10 by hot melt soldering. That is, the upper and lower surfaces of the PTC thermistor 4 are respectively soldered to the metal dummy cover 5 and the metal connecting piece 3 by hot melt soldering. Then, the metal connecting piece 3 is resistance-spot welded to the metal positioning piece 2 through the spot welding area 32, thus quickly realizing the installation of the PTC connection structure.

[0056] At this point, the battery cell 20, metal positioning piece 2, metal connecting piece 3, PTC thermistor 4, and metal dummy cover 5 form a vertical heat conduction path from bottom to top. The PTC thermistor 4 has a rapid thermal response, which can improve the sensitivity of overcurrent protection.

[0057] The working principle of this example is as follows: Within the mounting groove 11 of the plastic cover 1, the metal positioning piece 2 fits against the bottom of the groove 11 and is spot-welded to the battery cell 20 via the hollow boss 21. Then, on the outside of the battery casing 10, the metal connecting piece 3, the PTC thermistor 4, and the metal dummy cover 5 are hot-melt soldered together from bottom to top to form a whole. Finally, the metal connecting piece 3 is resistively spot-welded to the metal positioning piece 2, completing the installation of the top structure of the battery casing 10. When a large amount of heat is generated due to overcurrent within the battery cell, the heat is vertically conducted to the PTC thermistor 4 via the metal positioning piece 2 and the metal connecting piece 3, thus achieving overheat protection for the battery.

[0058] This invention, through structural innovation, maintains the PTC protection function while ensuring the surface of the dummy cover remains flat without any additional components. All parts are vertically stacked and connected, enabling the PTC to respond quickly. It is particularly suitable for the safety protection needs of miniaturized, high-energy-density batteries.

Claims

1. A battery PTC connection structure, characterized in that, include: A plastic cover (1) is provided on the top of the battery housing (10) and has an open mounting groove (11). The mounting groove (11) has a through hole (12) through which the power supply core (20) passes upward. Metal positioning piece (2), the metal positioning piece (2) is disposed in the mounting groove (11) and connected to the battery cell (20); PTC thermistor (4), the PTC thermistor (4) is annular and is connected above the metal positioning piece (2) in the mounting groove (11); A metal dummy cover (5) is provided in the mounting groove (11) and its bottom surface is connected to the PTC thermistor (4). The mounting groove (11) is provided with an anti-rotation component to limit the rotation of the metal positioning piece (2) and the metal dummy cover (5).

2. The battery PTC connection structure as described in claim 1, characterized in that, The anti-rotation component includes an anti-rotation protrusion (13) with the groove wall of the mounting groove (11) facing inward, and anti-rotation notches (6) on the outer edges of the metal positioning piece (2) and the metal false cover (5) corresponding to the anti-rotation protrusion (13).

3. The battery PTC connection structure as described in claim 2, characterized in that, The through hole (12) is located at the center of the mounting groove (11), and the metal positioning piece (2) protrudes to form a hollow boss (21). The hollow boss (21) and the through hole (12) are vertically aligned and used for welding the battery cell (20) into the hollow boss (21).

4. The battery PTC connection structure as described in claim 3, characterized in that, The inner ring of the PTC thermistor (4) passes through the hollow boss (21), and the PTC thermistor (4) is directly welded to the upper surface of the metal positioning piece (2) or welded to the upper surface of the metal positioning piece (2) through the metal connecting piece (3).

5. The battery PTC connection structure as described in claim 4, characterized in that, The metal connecting piece (3) is an annular structure with the inner ring passing through the hollow boss (21). The metal connecting piece (3) has an edge notch (31) corresponding to the anti-rotation protrusion (13). The metal false cover (5), PTC thermistor (4), and metal connecting piece (3) are connected into a whole by hot melt soldering.

6. The battery PTC connection structure as described in claim 5, characterized in that, The outer diameter of the metal dummy cover (5), the outer diameter of the metal connecting piece (3), and the outer diameter of the metal positioning piece (2) all correspond to the inner diameter of the mounting groove (11). The outer diameter of the PTC thermistor (4) is smaller than the outer diameter of the metal connecting piece (3), and the inner diameter is larger than the inner diameter of the metal connecting piece (3). The metal connecting piece (3) has a spot welding area (32) at the outer edge of the PTC thermistor (4).

7. The battery PTC connection structure as described in claim 6, characterized in that, The metal connecting piece (3) is resistance-welded to the metal positioning piece (2) through the spot welding area (32), and the metal false cover (5) is provided with an avoidance notch (51) corresponding to the spot welding area (32).

8. The battery PTC connection structure as described in claim 6, characterized in that, Two spot welding areas (32) are radially symmetrically arranged on the metal connecting piece (3).

9. The battery PTC connection structure as described in claim 2, characterized in that, The metal dummy cap (5) has an upward convex shape at the top center, forming a dummy cap convex cap (52) corresponding to the hollow convex platform (21).

10. The battery PTC connection structure as described in claim 1, characterized in that, The bottom surface of the plastic cover (1) is provided with a groove (14) for accommodating the battery cell sealing nail. The groove (14) is an annular ring arranged coaxially with the plastic cover (1).

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