Mechanical cutter

Abstract

The utility model discloses a mechanical cutter which comprises an elastic piece, a guide column, a limiting cap, two electrodes, two probes and a bridging assembly which are arranged in an inner cavity of a shell, the bridging assembly comprises a bridging piece and a heating piece, the bridging piece is attached to the heating piece, the two probes make contact with the heating piece, the two electrodes are electrically connected with the bridging piece through a first temperature sensing body, and the two electrodes are electrically connected with the bridging piece through a second temperature sensing body. One end of the guide column is connected with the shell, the other end of the guide column penetrates through the bridging assembly and then is connected with the limiting cap in a welded mode through the second temperature sensing body, the elastic piece is located between the bridging assembly and the shell, one end of the elastic piece abuts against the bridging assembly, and the other end of the elastic piece abuts against the shell. When a battery in a lithium battery system is overcharged or overdischarged, a control system starts a heating circuit in the mechanical cutter after detecting an abnormal signal, a heating sheet quickly transmits heat to a bridging sheet, and after a connecting alloy of an electrode sheet and the bridging sheet is fused, the bridging sheet is quickly bounced off under the elastic force of a compressed elastic piece, so that the battery is cut off. Meanwhile, a heating circuit is cooperatively cut off.

Description

Technical Field

[0001] The utility model relates to the field of circuit protection elements, in particular to a mechanical disconnector. Background Art

[0002] Currently, lithium battery protection systems or energy storage systems on the market mostly use MOS tubes as primary protection. If the MOS tube fails and the circuit cannot be disconnected in time, it can easily lead to safety accidents. This technology can be used as secondary protection for the circuit. In the event of battery overcharge or over-discharge, if the primary protection fails, the product will quickly activate the heating circuit to fuse the main circuit and simultaneously disconnect the control circuit, avoiding safety risks in the circuit and thus protecting the entire system. The controlled fuses currently used in the secondary protection market are alloy-type controlled fuses, which have a long melting time. Utility Model Content

[0003] In response to the deficiencies of the prior art, the present invention provides a mechanical disconnector that can serve as a secondary protection device when an overcharge / discharge anomaly occurs in a high-current module, quickly cutting off the circuit and protecting the battery safety.

[0004] To achieve the above-mentioned purpose, the present invention is realized through the following technical solutions:

[0005] A mechanical cutter includes an elastic part, a guide column, a limit cap, two electrodes, two probes, and a bridge assembly arranged in the inner cavity of a shell. The bridge assembly includes a bridge plate and a heating plate. The bridge plate and the heating plate are in contact with each other. The two probes are in contact with the heating plate. The two electrodes are electrically connected to the bridge plate through a first temperature sensor. The limit cap is located on the side of the bridge plate facing away from the heating plate. One end of the guide column is connected to the shell, and the other end passes through the bridge assembly and is welded to the limit cap through a second temperature sensor. The elastic part is located between the bridge assembly and the shell. One end of the elastic part pushes the bridge assembly, and the other end pushes the shell.

[0006] Furthermore, the bridging assembly also includes a connecting piece, the heating plate is located between the connecting piece and the bridging piece, and a buckle is provided on the connecting piece, and the connecting piece fastens the bridging piece through the buckle to make the heating plate and the bridging piece tightly attached.

[0007] Furthermore, the connecting piece is integrally formed of plastic material.

[0008] Furthermore, the connecting piece is located below the heating plate, the bridging piece is located above the heating plate, the buckle on the connecting piece extends upward to buckle the bridging piece, the connecting piece, the heating plate and the bridging piece are provided with corresponding through holes for the guide column to pass through, the upper end of the elastic piece abuts the bottom surface of the connecting piece, and the limiting cap is located above the bridging piece.

[0009] Furthermore, a groove for accommodating the second temperature sensor is provided on the bridge piece at a position corresponding to the limiting cap, and the limiting cap covers the groove.

[0010] Furthermore, the first temperature sensing body is a low melting point alloy or a fusible alloy; the second temperature sensing body is a low melting point alloy or a fusible alloy.

[0011] Furthermore, the melting point of the first temperature sensing element is lower than the melting point of the second temperature sensing element.

[0012] Furthermore, the electrode is L-shaped, including a horizontal part and a vertical part. The top surface of the horizontal part is welded to the bottom surface of the bridge plate, and the vertical part is connected to the side of the horizontal part away from the other electrode. Several notches are provided on the bottom edge of the vertical part, and stepped structures are provided on both sides of the width direction of the vertical part.

[0013] Furthermore, the shell includes a base and a cover plate, the base has an inner cavity, the cover plate covers the opening of the base, the base and the cover plate are connected by a snap-fit structure, through holes are provided on the base corresponding to the probe and electrode positions, the guide column is connected to the base, and one end of the elastic member pushes the base.

[0014] Furthermore, the elastic member is a spring, and the spring is sleeved on the guide column.

[0015] The utility model has the following beneficial effects:

[0016] 1. When the battery in the lithium battery system is overcharged or over-discharged, the control system detects the abnormal signal and starts the heating circuit in the mechanical disconnector. The heating plate quickly transfers heat to the bridge plate, and after melting the connecting alloy between the electrode plate and the bridge plate, the bridge plate is quickly opened under the elastic force of the compressed elastic member, and the heating circuit is cut off at the same time.

[0017] 2. Use an elastic member to cut off the circuit between the two electrodes. The guide column guides the elastic member so that the elastic member exerts a balanced thrust on the bridge piece, which is conducive to separating the bridge piece from the two electrodes at the same time.

[0018] 3. Using two temperature sensors with different melting points, after the first temperature sensor between the bridge piece and the two electrodes is completely melted, the welding relationship between the bridge piece and the two electrodes is completely disconnected. At this time, the second temperature sensor has not yet reached the melting point. The elastic part, guide column and limit cap cooperate so that the limit cap applies pressure to the bridge piece to prevent the bridge piece from separating from the two electrodes. When the second temperature sensor continues to absorb heat and reaches the melting point, the limit cap separates from the guide column, and the elastic part rebounds to push the bridge piece away from the two electrodes, thereby ensuring that the bridge piece is electrically disconnected from the two electrodes at the same time, avoiding the problem of arcing caused by the bridge piece being separated from a single electrode first. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an exploded schematic diagram of a mechanical cutter according to an embodiment of the present invention;

[0020] Figure 2 This is the assembly drawing of the bridge piece, heating piece and connector;

[0021] Figure 3 This is the internal structure diagram of the mechanical cutter under normal working conditions;

[0022] Figure 4 This is a diagram of the internal structure of the mechanical disconnector after both the first and second temperature sensors have melted. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0024] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0025] like Figures 1 to 4 As shown, this embodiment discloses a mechanical cutter, including an elastic member 110, a guide column 108, a limiting cap 109, two electrodes (respectively a first electrode 103 and a second electrode 104), two probes (a first probe 111a and a second probe 111b), and a bridge component arranged in the inner cavity of the shell. The bridge component includes a bridge piece 105 and a heating plate 106. The bridge piece 105 and the heating plate 106 are in contact with each other, and the two probes are in contact with the heating plate 106. The two electrodes are electrically connected to the bridge piece 105 through a first temperature sensor. The guide column passes through the bridge component. The limiting cap 109 is located on the side of the bridge piece facing away from the heating plate and is welded to the guide column 108 through a second temperature sensor. One end of the guide column 108 is connected to the shell, and the other end passes through the bridge component and is welded to the limiting cap through the second temperature sensor. The elastic member is located between the bridge component and the shell, and one end of the elastic member pushes the bridge component and the other end pushes the shell. If a lithium battery is overcharged or over-discharged, the battery temperature will rise sharply. If a lithium battery is over-discharged or over-charged abnormally, the battery voltage will decrease or the current will increase. The BMS system detects the abnormal signal and activates the battery protection system. If the primary protection MOS tube fails, this product will be activated for secondary protection. In a lithium battery system, if the battery is overcharged or over-discharged, the control system detects the abnormal signal and activates the heating circuit within the mechanical disconnector. After fusing the alloy connecting the electrode sheet and the bridge sheet, the elastic force of the compressed elastic member rapidly opens the bridge sheet, simultaneously disconnecting the heating circuit.

[0026] The guide column 108 passes through the elastic member 110, the heating plate 106, the bridge plate 105 and the limiting cap 109 in sequence. The limiting cap 109 is welded to the side of the bridge plate 105 facing away from the heating plate through the second temperature sensor. The elastic member 110 is compressed and provides a thrust to the bridge plate 105 to keep the bridge plate 105 away from the two electrodes. The melting point of the first temperature sensor is lower than the melting point of the second temperature sensor. After the first temperature sensor between the bridge plate 105 and the two electrodes is completely melted, the welding relationship between the bridge plate 105 and the two electrodes is completely disconnected. Then the second temperature sensor continues to absorb heat and reaches the melting point. The limiting cap 109 separates from the guide column 108, and the elastic member 110 rebounds to push the bridge plate 105 away from the two electrodes, thereby ensuring that the bridge plate 105 is electrically disconnected from the two electrodes at the same time, avoiding the problem of the bridge plate 105 being separated from a single electrode first, causing an arc.

[0027] A groove for accommodating the temperature sensor is provided on the bridge piece 105 at the position corresponding to the limiting cap 109. The size of the limiting cap 109 is larger than the groove. The limiting cap 109 covers the groove to prevent the alloy melt from flowing randomly. The limiting cap 109 plays the role of controlling the flow direction of the temperature sensor melt.

[0028] The melting point of the first temperature sensor is lower than that of the second temperature sensor. The bridge piece 105 is first disconnected from the welded portion of the two electrodes, and then the limiting cap is disconnected from the bridge piece 105. Without the limiting cap 109, when the bridge piece 105 is heated unevenly, the bridge piece 105 and the two electrodes may not separate at the same time. The bridge piece 105 will tilt up and separate from one of the electrodes first. By adding the limiting cap, the limiting cap 109 is affected by the elastic force of the elastic member 110 and presses the bridge piece 105 before the second temperature sensor melts, thereby ensuring that the bridge piece 105 is disconnected from the welded portions of the two electrodes before separating from the two electrodes at the same time.

[0029] Because the elastic member 110 is in a compressed state, the elastic member 110 exerts a thrust on the bridge piece 105. If the limiting cap 109 is not present and the tail of the guide post 108 is directly welded to the bridge piece 105 through a temperature sensor, it is difficult to control the bridge piece 105 to be perpendicular to the guide post 108, which may cause problems such as the guide post 108 being welded crookedly and the welding being unstable. If the guide post 108 is welded crookedly, the thrust of the elastic member 110 on the bridge piece 105 will be unbalanced, causing the bridge piece 105 and the two electrodes to be unable to separate at the same time, thereby generating an arc between the bridge piece 105 and the electrode that was separated first. Therefore, the limiting cap 109 facilitates the assembly of the guide post 108 and ensures that the guide post 108 is perpendicular to the bridge piece 105, that is, ensures that the elastic member 110 is perpendicular to the bridge piece 105.

[0030] The first temperature sensor is a low melting point alloy or a fusible alloy. The second temperature sensor is a low melting point alloy or a fusible alloy. In other embodiments, the materials of the first temperature sensor and the second temperature sensor are not limited to low melting point alloys or fusible alloys, and may also be made of other suitable materials (such as composite materials).

[0031] The shell includes a base 102 and a cover 101. The base 102 has an inner cavity. The cover 101 covers the opening of the base 102. The bridging assembly and the elastic member are enclosed in the cavity formed by the cover 101 and the base 102. In this embodiment, the base 102 and the cover 101 are connected by a snap-fit structure. The cover 101 is provided with a snap-fit and the base 102 is provided with a slot. In other embodiments, a slot may also be provided on the cover 101 and a snap-fit may be provided on the base 102. The cover 101 and the base 102 are not limited to snap-fit connection. For example, ultrasonic welding may also be used. Through holes are provided on the base 102 corresponding to the positions of the probe and the electrode. The probe and the electrode are connected to an external PCB or the like through the through holes. The bottom of the guide column is fixed to the base, and one end of the elastic member pushes against the base.

[0032] The bridging assembly also includes a connector 107, and the heating plate is located between the connector 107 and the bridging plate 108. The connector 107 is provided with a buckle, and the connector 107 fastens the bridging plate 105 through the buckle so that the heating plate 106 is in close contact with the bridging plate 105. Preferably, the connector 107 is provided with at least two opposite buckles that are engaged with the bridging plate 105, and the heating plate 106 is clamped by the connector 107 and the bridging plate 105, and the heating plate 106 is in close contact with the bridging plate 105. The connector 107 can be made of plastic or other insulating materials. The connector 107 in this embodiment is integrally formed of plastic, and a clearance structure (a notch or a through hole is provided for the probes to pass through) is provided on the connector 107 at the positions corresponding to the two probes.

[0033] The bridge piece 105 is located above the heating sheet 106, and the connector 107 is located below the heating sheet 106. The buckle on the connector 107 extends upward to buckle the bridge piece 105. The connector 107, the heating sheet 106, and the bridge piece 105 are assembled into a component. The three are provided with corresponding through holes for the guide column 108 to pass through. The limit cap 109 is located above the bridge piece 105, and the elastic member 110 abuts the bottom surface of the connector 107. The width of the connector 107 and the width of the heating sheet 106 are both smaller than the gap between the two electrodes, which is used to avoid the electrodes. When the elastic member returns, it is pushed away from the electrodes without obstruction.

[0034] The bottom surface of the heating plate 106 has a first groove 106a corresponding to the first probe position and a second groove 106b corresponding to the second probe position. The heating plate 106 is generally a ceramic piece, and the first and second grooves are provided with pins of the heating plate.

[0035] The electrode is bent into an L-shape, including a horizontal portion and a vertical portion. The horizontal portion is welded to the side of the bridge piece 105 close to the elastic member 110 through the first temperature sensor, and the vertical portion is perpendicular to the base 102. The two probes and the elastic member 110 are located between the two electrodes. The two electrodes are symmetrically arranged. The top surface of the horizontal portion is welded to the bottom surface of the bridge piece, and the welding area is large. The vertical portion is connected to the side of the horizontal portion away from the other electrode, so that there is enough space between the two vertical portions for installing the probe and the elastic member 110. There are several notches on the bottom edge of the vertical portion, and the electrodes can be screwed to other electrical appliances through the several notches. There are step structures on both sides of the vertical portion in the width direction, and the electrode can be plugged into other electrical appliances through the step structures. The vertical portion can also be welded with leads, and external electrical appliances can be connected through the leads.

[0036] In this embodiment, the heating sheet is narrower than the bridge sheet, and the two electrodes are located on the same side of the bridge sheet. In other embodiments, the two electrodes may also be connected to both ends of the bridge sheet respectively, and the width of the heating sheet may be increased.

[0037] The elastic member is preferably a spring, and the elastic member can also be a spring sheet, a polymer elastic block, etc.

[0038] The working principle of the mechanical cutter is as follows:

[0039] After receiving the signal sent by BMS, the heating circuit of the product is started through the two probes 111. The normal working state is as follows Figure 3 , the heating circuit is connected by the first probe 111a through the first groove 106a, and the second groove 106b is connected to the second probe 111b. The above is a complete heating circuit path. When the heating plate 106 is started, the bridge piece stuck together with the heating plate 106 will quickly obtain the heat of the heating plate 106, and the limiting cap 109 and the guide column 108 welded together with the temperature sensor, the bridge piece 105, the first electrode 103 and the second electrode 104 The temperature sensor is quickly melted, and at the same time, the bridge piece 105 and the heating plate 106 are clamped together by buckles. When the melting temperature of the second temperature sensor is reached, the bridge piece 105 and the heating plate 106 will be quickly bounced up under the action of the elastic member 110 to cut off the heating circuit. The disconnected state is as follows Figure 4 .

[0040] This mechanical disconnector utilizes two temperature sensors with different melting points. Under normal operation, the first and second temperature sensors simultaneously store thermal energy and mechanical energy from the elastic element 110. In the event of a circuit fault, the elastic element 110 utilizes both thermal and mechanical energy to disconnect the circuit, mechanically controlling the disconnection. This serves as secondary protection for lithium batteries, with a current range of 200 to 500A. This mechanical disconnector can be connected to an external electrical device through various means, including plug-in, wired, and screw-on connections.

[0041] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present invention.

Claims

1. A mechanical cutter, characterized in that: It includes an elastic part, a guide column, a limit cap, two electrodes, two probes, and a bridge assembly arranged in the inner cavity of the shell. The bridge assembly includes a bridge plate and a heating plate. The bridge plate and the heating plate are in contact with each other. The two probes are in contact with the heating plate. The two electrodes are electrically connected to the bridge plate through a first temperature sensor. The limit cap is located on the side of the bridge plate facing away from the heating plate. One end of the guide column is connected to the shell, and the other end passes through the bridge assembly and is welded to the limit cap through the second temperature sensor. The elastic part is located between the bridge assembly and the shell. One end of the elastic part pushes the bridge assembly and the other end pushes the shell.

2. The mechanical cutter according to claim 1, characterized in that The bridging assembly also includes a connecting piece, the heating plate is located between the connecting piece and the bridging piece, and a buckle is provided on the connecting piece. The connecting piece fastens the bridging piece through the buckle so that the heating plate and the bridging piece are in close contact.

3. The mechanical cutter according to claim 2, characterized in that The connecting piece is integrally formed of plastic material.

4. The mechanical cutter according to claim 2, characterized in that The connecting piece is located below the heating plate, the bridging piece is located above the heating plate, the buckle on the connecting piece extends upward to buckle the bridging piece, the connecting piece, the heating plate and the bridging piece are provided with corresponding through holes for the guide column to pass through, the upper end of the elastic piece abuts the bottom surface of the connecting piece, and the limiting cap is located above the bridging piece.

5. The mechanical cutter according to claim 1, characterized in that A groove for accommodating the second temperature sensor is provided at a position corresponding to the limiting cap on the bridge piece, and the limiting cap covers the groove.

6. The mechanical cutter according to claim 1, characterized in that The first temperature sensing body is a low melting point alloy or a fusible alloy; the second temperature sensing body is a low melting point alloy or a fusible alloy.

7. The mechanical cutter according to claim 1, characterized in that The melting point of the first temperature sensing element is lower than the melting point of the second temperature sensing element.

8. The mechanical cutter according to claim 1, characterized in that The electrode is L-shaped, including a horizontal part and a vertical part. The top surface of the horizontal part is welded to the bottom surface of the bridge piece, and the vertical part is connected to the side of the horizontal part away from the other electrode. There are several notches on the bottom edge of the vertical part, and a stepped structure is provided on both sides of the width direction of the vertical part.

9. The mechanical cutter according to claim 1, characterized in that The shell includes a base and a cover plate. The base has an inner cavity. The cover plate covers the opening of the base. The base and the cover plate are connected by a snap-fit structure. Through holes are provided on the base corresponding to the positions of the probe and electrode. The guide column is connected to the base, and one end of the elastic member pushes the base.

10. The mechanical cutter according to claim 1, characterized in that The elastic member is a spring, which is sleeved on the guide column.

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