Mechanical disconnector

Abstract

The present application relates to the technical fields of electrical protection device, in particular to a mechanical disconnector, which comprises a bridge piece, a heating piece, a spring, two electrode pieces, a PCB board, a first pin, a second pin and two contact pins, the opposite ends of the bridge piece are respectively welded with the two electrode pieces through fusible alloy, the heating piece is placed below the bridge piece, the first pin and the second pin are welded with the PCB board, the two contact pins abut against the heating piece, and the two contact pins are welded with the PCB board. By virtue of the setting, the mechanical disconnector can avoid direct welding of the pin and the contact pin, and can avoid problems such as not easy to bend, poor welding consistency, not easy to control the pin leading position and the like.

Description

Technical Field

[0001] This invention relates to the field of electrical protection devices, and in particular to a mechanical cut-off device. Background Technology

[0002] Currently, most lithium battery protection systems or energy storage systems on the market use MOSFETs as the primary protection. When the circuit experiences overvoltage or overtemperature, the failure of the MOSFET can lead to the circuit not being able to disconnect in time, resulting in safety risks. In this case, the secondary protection of the circuit needs to be activated. In the event of battery overcharging / discharging, if the primary protection malfunctions, the product will quickly activate the heating circuit to melt the main circuit and simultaneously disconnect the control circuit to avoid safety risks and thus protect the entire system.

[0003] Currently, the controlled fuses used for secondary protection in the market are alloy-type controlled fuses, which have long melting times and insufficient breaking capacity. Some manufacturers have begun to use mechanical controlled fuses to improve breaking capacity. However, the pins of existing mechanical controlled fuses need to be soldered to probes, as illustrated in Chinese patent publication number CN116417304A. This requires soldering, resulting in a larger solder joint area, making bending difficult, and leading to poor solder consistency and difficulty in controlling the pin lead-out position. This not only makes the manufacturing process more complicated, but also causes solder joint detachment due to bending stress during high-temperature operation, affecting product performance.

[0004] It should be noted that the information disclosed in this background section is intended only to enhance the understanding of the overall background of the present invention, and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] This invention provides a mechanical cutter, comprising a bridging plate, a heating element, two electrode plates, a PCB board, a first pin, a second pin, and two ejector pins. The two ends of the bridging plate are respectively welded to the two electrode plates via a fusible alloy. The heating element is positioned below the bridging plate. The first pin and the second pin are welded to the PCB board. The two ejector pins abut against the heating element and are also welded to the PCB board.

[0006] Furthermore, the mechanical cutter also includes a limiting rod, and the bridging piece has an opening in the middle. The limiting rod passes through the opening, and the limiting rod and the bridging piece are welded together by a high-melting-point alloy, the melting point of which is higher than that of the fusible alloy.

[0007] Furthermore, the melting point of the high-melting-point alloy is more than 5°C higher than that of the fusible alloy.

[0008] Furthermore, the bridging piece is provided with a narrow diameter.

[0009] Furthermore, the bridging piece is a butterfly-shaped bridging piece, and the intersection of the arcs on both sides of the bridging piece is a narrow diameter.

[0010] Furthermore, the heating element and the bridging element are in close contact.

[0011] Furthermore, the two electrode plates are planar electrodes.

[0012] Furthermore, the mechanical cutter also includes a rubber ring, which is fitted onto the electrode plate.

[0013] Furthermore, the mechanical cutter also includes a housing, within which the bridging plate, the heating element, the PCB board, and the two ejector pins are disposed.

[0014] Furthermore, the mechanical cutter also includes a base that is connected to the housing.

[0015] Furthermore, the first pin, the two pins, the heating element, and the second pin are connected in series.

[0016] The mechanical cutter provided by the present invention avoids direct soldering of the pins and pins by directly soldering the first pin, the second pin and the two ejector pins to the PCB board, thus avoiding problems such as difficulty in bending, poor soldering consistency and difficulty in controlling the pin lead-out position.

[0017] Other features and advantages of the present invention will be set forth in the following description, and some of the technical features and advantages may be apparent from the description or learned by practicing the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, some of the drawings in the following description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a perspective view of a mechanical cutter provided in an embodiment of the present invention; Figure 2 This is an exploded schematic diagram of a mechanical cutter provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of a mechanical cutter using a butterfly-shaped bridging piece under normal operating conditions according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a mechanical cutter in the disconnected state using a butterfly-shaped bridging piece, provided by an embodiment of the present invention.

[0020] Figure label: 101-Outer shell; 102-Base; 103-Electrode plate; 104-Bridging plate; 105-Heating element; 106-Spring; 107a, 107b-Ejector pins; 108-Rivet; 109-PCB board; 110-Washer; 111-Butterfly-shaped bridging plate; 112-Rubber ring; 113a-First pin; 113b-Second pin; 114-Limiting rod. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] In the description of this invention, it should be understood that the terms "center," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "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 component 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 this invention, unless otherwise stated, "a plurality of" means two or more. Additionally, the term "comprising" and any variations thereof mean "at least comprising."

[0023] Please see Figures 1 to 4 , Figure 1 This is a perspective view of a mechanical cutter provided in an embodiment of the present invention. Figure 2 This is an exploded view of a mechanical cutter according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of a mechanical cutter using a butterfly-shaped bridging piece 111 in normal working condition according to an embodiment of the present invention. Figure 4 This is a schematic diagram of a mechanical cutter in the disconnected state according to an embodiment of the present invention, employing a butterfly-shaped bridging piece 111. To achieve at least one or more of the aforementioned advantages, an embodiment of the present invention provides a mechanical cutter. This mechanical cutter may include a bridging piece 104, a heating element 105, a spring 106, two electrode pieces 103, a PCB board 109, a first pin 113a, a second pin 113b, and two ejector pins 107a and 107b. The PCB board 109 includes an insulating material with circuitry.

[0024] The two ends of the bridging piece 104 are welded to the two electrode pieces 103 respectively via fusible alloy. The heating element 105 is connected to the bridging piece 104. One end of the spring 106 abuts against the bridging piece 104. Under normal operating conditions, the spring 106 is in a compressed state. Subsequently, when the heating circuit is active, the spring 106 can be used to separate the bridging piece 104 from the two electrode pieces 103 to cut off the heating circuit. The first pin 113a and the second pin 113b are soldered to the PCB board 109. The spring 106 is located between the two ejector pins 107a and 107b, which are soldered to the PCB board 109. Since the two ejector pins 107a and 107b are directly soldered to the PCB board 109 and then led out by the two pins, the overall installation and operation are convenient. In this case, the two ejector pins 107a and 107b and the pins 113a and 113b are soldered onto the PCB board 109 respectively. The soldering process is simple and can effectively shorten the manufacturing process. Furthermore, since there is no bending between the ejector pins 107a and 107b and the pins 113a and 113b, the solder will not fall off due to stress caused by working in a high-temperature environment, thus ensuring the reliability of the product.

[0025] For example, in the event of overcharging or over-discharging of a lithium battery, the battery temperature will rise sharply, the battery voltage will drop, and the current will increase. After the BMS system detects the abnormal signal, it activates the battery protection system. In the event of a failure of the primary protection MOSFET, the mechanical cut-off device is activated for secondary protection. Its working principle is as follows: After receiving the signal sent by the BMS, the heating circuit is started through the first pin 113a and the second pin 113b. The complete path of the heating circuit is: first pin 113a → PCB board 109 → ejector pin 107a → heating element 105 → ejector pin 107b → second pin 113b.

[0026] When the heating element 105 is activated, heat is rapidly transferred to the bridging plate 104 because the heating element 105 is connected to the bridging plate 104. This heat causes the fusible alloy on both sides and in the middle of the bridging plate 104 to melt rapidly. The spring 106 releases its elastic force, and under the action of the spring 106 or the ejector pins 107a and 107b, the bridging plate 104 quickly springs up to cut off the heating circuit. The disconnected state can be referenced. Figure 4 As shown, the normal working state can be referenced. Figure 3 As shown. In some embodiments, the spring 106 may be omitted, and the retraction displacement of the ejector pins 107a and 107b may be increased to push the bridging piece 104 out, thereby cutting off the circuit.

[0027] In some embodiments, the mechanical cutter further includes a limiting rod 114. An opening is provided in the middle of the bridging piece 104, through which the limiting rod 114 passes. The limiting rod 114 and the bridging piece 104 are welded together by a high-melting-point alloy, the melting point of which is higher than that of the fusible alloy. After the fusible alloy melts, the high-melting-point alloy can still act as a limiting agent, thereby controlling that the fusible alloy at both ends of the bridging piece 104 can be in a molten state simultaneously. Optionally, the melting point of the high-melting-point alloy is more than 5°C higher than that of the fusible alloy.

[0028] In some embodiments, the heating element 105 and the bridging element 104 are closely fitted to facilitate heat transfer and ensure timely disconnection of the heating circuit.

[0029] In some embodiments, the two electrode plates 103 are planar electrodes.

[0030] In some embodiments, the mechanical cutter further includes a rubber ring 112, a washer 110, a housing 101, and a base 102. The rubber ring 112 is fitted onto the electrode plate 103 to provide a seal. The washer 110 is located between the spring 106 and the heating element 105, and when disconnected, it supports the bridging piece 104 to prevent it from tilting and arcing when it springs open. The bridging piece 104, the heating element 105, the spring 106, the PCB board 109, and the two ejector pins 107a and 107b are disposed inside the housing 101, which provides protection. The base 102 is connected to the housing 101. In some embodiments, the first pin 113a, the two ejector pins 107a and 107b, the heating element 105, and the second pin 113b are connected in series.

[0031] In some embodiments, the mechanical cutter further includes a rivet 108 for attaching the electrode sheet 103 to the housing 101.

[0032] In some embodiments, such as Figure 3As shown, a narrow aperture is provided on the bridging piece 104 to achieve the overcurrent function. To prevent the heating element 105 from being ablated during the arcing process at the narrow aperture point, the bridging piece 104 is X-shaped. Alternatively, a butterfly-shaped bridging piece 111 formed by two intersecting C-shaped electrodes can be used, with the narrow aperture at the intersection of the arcs on both sides of the butterfly-shaped bridging piece 111. The butterfly-shaped bridging piece 111 can effectively prevent the heating element 105 from breaking down and shorten the heating time; the butterfly-shaped bridging piece 111 has a fast melting speed, is not prone to arcing, and has a low probability of arcing.

[0033] In summary, the mechanical cutter provided by the present invention eliminates the need for direct soldering of the pins to the pins 107a and 107b by directly soldering the first pin 113a, the second pin 113b, and the two ejector pins 107a and 107b onto the PCB board 109, thus avoiding problems such as difficulty in bending, poor soldering consistency, and difficulty in controlling the pin lead-out position.

[0034] Furthermore, those skilled in the art should understand that although many problems exist in the prior art, each embodiment or technical solution of the present invention can be improved in only one or a few aspects, without necessarily solving all the technical problems listed in the prior art or the background art simultaneously. Those skilled in the art should understand that any content not mentioned in a claim should not be construed as a limitation on that claim.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mechanical cutter, characterized in that: The mechanical cutter includes a bridging plate, a heating element, two electrode plates, a PCB board, a first pin, a second pin, and two ejector pins; The two ends of the bridging piece are respectively welded to the two electrode pieces by a fusible alloy. The heating element is placed below the bridging piece. The first pin and the second pin are welded to the PCB board. The two ejector pins abut against the heating element and are also welded to the PCB board.

2. The mechanical cutter according to claim 1, characterized in that: The mechanical cutter also includes a limiting rod. The bridging piece has an opening in the middle, through which the limiting rod passes. The limiting rod and the bridging piece are welded together by a high-melting-point alloy, the melting point of which is higher than that of the fusible alloy.

3. The mechanical cutter according to claim 2, characterized in that: The melting point of the high-melting-point alloy is more than 5°C higher than that of the fusible alloy.

4. The mechanical cutter according to claim 1, characterized in that: The bridging piece is provided with a narrow diameter.

5. The mechanical cutter according to claim 1, characterized in that: The bridging piece is a butterfly-shaped bridging piece, and the intersection of the arcs on both sides of the bridging piece is a narrow diameter.

6. The mechanical cutter according to claim 1, characterized in that: The heating element and the bridging element are in close contact.

7. The mechanical cutter according to claim 1, characterized in that: The two electrode plates are planar electrodes.

8. The mechanical cutter according to claim 1, characterized in that: The mechanical cutter also includes a rubber ring, which is fitted onto the electrode plate.

9. The mechanical cutter according to claim 1, characterized in that: The mechanical cutter also includes a housing, and the bridging plate, the heating element, the PCB board and the two ejector pins are disposed inside the housing.

10. The mechanical cutter according to claim 1, characterized in that: The first pin, the two pins, the heating element, and the second pin are connected in series.

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