Double-loop protection fuse

Abstract

The utility model relates to a double-loop protection fuse which comprises a series loop terminal and a parallel loop terminal. The middle section of the parallel loop terminal is provided with a narrow neck part, and the side, close to the narrow neck part, of the parallel loop terminal is connected with the series loop terminal through a low-melting-point alloy; a gap is formed between the series loop terminal and the parallel loop terminal, and an insulating spacer is inserted into the gap; the series loop terminal, the parallel loop terminal, the low-melting-point alloy and the insulating spacer are all arranged in the shell, and one end of the series loop terminal and the two ends of the parallel loop terminal are exposed out of the outer side of the shell respectively; wherein one end of the series loop terminal is welded with a next single battery of the series bridge, one end, connected with the series loop terminal, of the parallel loop terminal is welded with a battery pole, and the other end of the parallel loop terminal is welded with a next single battery of the parallel bridge. When the single batteries of the battery pack are in thermal runaway, the series bridge circuit and the parallel bridge circuit can be cut off, so that a fault battery island is established.

Description

Technical Field

[0001] The utility model belongs to the technical field of electronic components, and in particular relates to a double-circuit protection fuse. Background Art

[0002] Fuses, commonly known as "fuse", are an overcurrent protection device, mainly used as circuit protection devices in battery packs for short circuit protection or overload protection. The mainstream thermal fuses on the market are composed of insulating tubes, terminals, covers, fuses, arc extinguishing media and other auxiliary materials. Their working principle is: under specified voltage conditions, the line current passes through the fuse, and the current thermal effect is used. When the heat accumulates to a certain extent, the current sensing point of the fuse melts and disconnects within a specified time, thereby safely disconnecting the fault current.

[0003] In group applications, battery packs usually use a single cell series-parallel structure to increase capacity. Generally, battery thermal runaway usually occurs in the form of an internal short circuit in a single cell. When a single cell thermal runaway occurs, heat transfer occurs in the series circuit, increasing the risk of thermal runaway of surrounding battery cells. The parallel circuit generates current backflow and overcurrent, which accelerates the thermal runaway process of the faulty battery. Therefore, how to isolate the faulty battery according to the different failure mechanisms of the series-parallel circuit is an urgent problem to be solved in the industry. Utility Model Content

[0004] In view of the deficiencies of the prior art, the utility model provides a dual-circuit protection fuse, which can cut off the series bridge and parallel bridge circuits when a single cell of a battery pack experiences thermal runaway, thereby achieving the establishment of a faulty battery island.

[0005] In order to achieve the above object, the technical solution of the utility model is:

[0006] A double-circuit protection fuse comprises a series circuit terminal and a parallel circuit terminal; the parallel circuit terminal is provided with a narrow neck portion in the middle section, and is connected to the series circuit terminal through a fuse alloy on a side close to the narrow neck portion; a gap is formed between the series circuit terminal and the parallel circuit terminal, and an insulating spacer is inserted into the gap;

[0007] The series circuit terminal, the parallel circuit terminal, the fuse alloy and the insulating spacer are all placed in the housing, and one end of the series circuit terminal and both ends of the parallel circuit terminal are respectively exposed to the outside of the housing;

[0008] Among them, one end of the series loop terminal is welded to a single battery under the series bridge, and the parallel loop terminal is connected to one end of the series loop terminal and welded to the battery pole, and the other end is welded to a single battery under the parallel bridge.

[0009] In the above-mentioned dual-circuit protection fuse, the series circuit terminal is an aluminum strip made of aluminum material, and the aluminum strip is bent at 90 degrees.

[0010] In the above-mentioned dual-circuit protection fuse, the parallel circuit terminal is a copper strip made of copper material, and the narrow neck portion thereof is formed by circular holes spaced apart longitudinally.

[0011] In the above-mentioned dual-circuit protection fuse, a cavity is formed in the shell, and the series circuit terminal, parallel circuit terminal, fuse alloy and insulating spacer are all placed in the cavity of the shell.

[0012] Technical effects and advantages of the utility model:

[0013] The utility model provides a dual-circuit protection fuse, which connects the series circuit terminal with the parallel circuit terminal through a fuse alloy, sets a narrow neck on the parallel circuit terminal, inserts an insulating spacer between the series circuit terminal and the parallel circuit terminal, and places the assembled series circuit terminal, fuse alloy, parallel circuit terminal and insulating spacer in a shell with a cavity. When a single battery cell has thermal runaway, the current of the parallel bridge circuit flows back, and the narrow neck of the parallel circuit of the fuse first senses the fault and performs overcurrent melting. The local high temperature of the narrow neck accelerates the melting of the low-melting-point tin-bismuth alloy, so that the molten tin-bismuth alloy flows into the bottom of the shell cavity, thereby cutting off the series circuit, and thus the faulty battery island is established, which will not affect other batteries. This structural design effectively avoids the phenomenon of heat transfer in the series circuit when a single battery cell has thermal runaway, greatly reduces the risk of thermal runaway of the surrounding battery cells, and greatly reduces the thermal runaway process of the faulty battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the explosion structure of the utility model;

[0015] Figure 2 It is a schematic diagram of the overall structure of the utility model;

[0016] Figure 3 yes Figure 2 AA cross-sectional structure schematic diagram.

[0017] Numbers in the figure: 1, insulating spacer; 2, series circuit terminal; 3, parallel circuit terminal; 31, narrow neck; 4, fuse alloy; 5, shell. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below with reference to the embodiments given in the accompanying drawings.

[0019] See also Figure 1As shown, a dual-circuit protection fuse of this embodiment includes an insulating spacer 1, a series circuit terminal 2, a parallel circuit terminal 3, a fuse alloy 4 and a shell 5.

[0020] A narrow neck portion 31 is provided in the middle of the parallel circuit terminal 3, and the side close to the narrow neck portion 31 is connected to the series circuit terminal 2 through a fuse alloy 4. A gap is formed between the series circuit terminal 2 and the parallel circuit terminal 3, and the insulating spacer 1 is inserted into the gap.

[0021] In a specific implementation, a cavity is formed in the shell 5, and the assembled series circuit terminal 2, parallel circuit terminal 3, fuse alloy 4 and insulating spacer 1 are placed in the cavity of the shell 5, and one end of the series circuit terminal 2 and both ends of the parallel circuit terminal 3 are respectively exposed to the outside of the shell 5 for easy welding with the battery.

[0022] During specific welding, one end of the series circuit terminal 2 is welded to a single battery under the series bridge, and one end of the parallel circuit terminal 3 connected to the series circuit terminal 2 is welded to the battery pole by cold welding, and the other end is welded to a single battery under the parallel bridge.

[0023] In this embodiment, the series circuit terminal 2 is connected to the narrow neck 31 on the parallel circuit terminal 3 through the fuse alloy 4, the insulating spacer 1 is inserted between the series circuit terminal 2 and the parallel circuit terminal 3, and the assembled series circuit terminal 2, the fuse alloy 4, the parallel circuit terminal 3 and the insulating spacer 1 are placed in the cavity shell 5, one end of the series circuit terminal 2 is welded to a single battery under the series bridge, and the end of the parallel circuit terminal 3 connected to the series circuit terminal 2 is welded to the battery pole by cold welding, and the other end is welded to a single battery under the parallel bridge. When the single battery has thermal runaway, the parallel bridge circuit current flows back, the parallel circuit narrow neck of the fuse first senses the fault and performs overcurrent melting, and the low melting point tin-bismuth alloy is melted by the local high temperature of the narrow neck, so that the molten tin-bismuth alloy flows into the bottom of the shell cavity, thereby cutting off the series circuit, so that the fault battery island is established, which will not affect other batteries.

[0024] Preferably, the series circuit terminal 2 is an aluminum strip made of aluminum material, and in order to facilitate welding with the battery, the aluminum strip is bent at 90 degrees.

[0025] Preferably, the parallel circuit terminal 3 is a copper strip made of copper material. The narrow neck portion 31 is formed by circular holes spaced apart longitudinally, and this structure can rapidly increase the local temperature of the narrow neck portion 31 , thereby accelerating the melting of the fusing alloy 4 .

[0026] By adopting the structural design of this embodiment, when thermal runaway of a single battery cell occurs, heat transfer in the series circuit is effectively avoided, the risk of thermal runaway of surrounding battery cells is greatly reduced, and the thermal runaway process of the faulty battery is greatly reduced.

[0027] The above is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A dual-circuit protection fuse, characterized in that: The invention comprises a series circuit terminal (2) and a parallel circuit terminal (3); a narrow neck portion (31) is provided in the middle of the parallel circuit terminal (3), and a side close to the narrow neck portion (31) is connected to the series circuit terminal (2) via a fuse alloy (4); a gap is formed between the series circuit terminal (2) and the parallel circuit terminal (3), and an insulating spacer (1) is inserted into the gap; The series circuit terminal (2), the parallel circuit terminal (3), the fuse alloy (4) and the insulating spacer (1) are all placed in a housing (5), and one end of the series circuit terminal (2) and both ends of the parallel circuit terminal (3) are respectively exposed to the outside of the housing (5).

2. A dual-circuit protection fuse according to claim 1, characterized in that: One end of the series circuit terminal (2) is welded to a single cell under the series bridge, and the parallel circuit terminal (3) is connected to one end of the series circuit terminal (2) and welded to a battery pole, and the other end is welded to a single cell under the parallel bridge.

3. A dual-circuit protection fuse according to claim 1, characterized in that: The series circuit terminal (2) is an aluminum strip made of aluminum material, and the aluminum strip is bent at 90 degrees.

4. A dual-circuit protection fuse according to claim 1, characterized in that: The parallel circuit terminal (3) is a copper strip made of copper material, and the narrow neck portion (31) thereon is formed by circular holes spaced apart in the longitudinal direction.

5. A dual-circuit protection fuse according to claim 1, characterized in that: A cavity is formed in the shell (5), and the series circuit terminal (2), the parallel circuit terminal (3), the fuse alloy (4) and the insulating spacer (1) are all placed in the cavity of the shell (5).

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