Battery pack cathode overcharge safety protection structure with self-cut-off function

Abstract

The invention discloses a battery pack cathode overcharge safety protection structure with a self-cut-off function, the battery pack cathode overcharge safety protection structure comprises a protection shell, a battery cell groove and a device groove are arranged in the protection shell, and two rows of battery cell modules arranged in sequence are fixedly mounted in the battery cell groove; a BMS control module, a fusing structure and a mechanical circuit breaking module are installed in the device groove, and the fusing structure comprises an insulation box. According to the invention, the self-resetting fuse and the disposable fuse are connected in series, so that a response is made to an overshoot abnormal circuit which has transient fluctuation and cannot fuse the disposable disconnector, and temporary circuit break protection is realized, and therefore, the device can protect the circuit by using the double-type fuses connected in series, and the reliability of the circuit breaker is improved. The quick-melting fuse has the advantages that the replacement frequency of the quick-melting fuse is reduced, the overall stability is improved, meanwhile, the accuracy of troubleshooting along subsequent overhaul is facilitated, the risk of re-damage of the quick-melting fuse is reduced, and the safety and convenience are improved.

Description

Technical Field

[0001] This invention relates to the field of battery pack overcharge safety protection technology, and more specifically, to a battery pack negative electrode overcharge safety protection structure with self-cut-off function. Background Technology

[0002] A battery pack is an energy storage device composed of multiple battery cells connected in series and parallel, and integrated with key components such as a battery management system (BMS) and a thermal management system. It is the power core of new energy vehicles and other equipment. Through modular design, it improves energy density and safety, and is equipped with anti-collision structure, sealed shell and intelligent monitoring system to achieve efficient storage and release of electrical energy.

[0003] Current overcharge protection methods for battery packs include voltage and current detection by the BMS to achieve intelligent monitoring of overcharge, and the combination of a fuse protection system, in which a fast-blow fuse is connected in series with the negative terminal of the circuit to quickly disconnect the circuit in case of BMS management failure or abnormal short circuit, and the use of a battery pack pressure relief valve for timely pressure relief and cooling to protect against overcharge.

[0004] However, current negative electrode fuse protection typically uses only a single fast-blow fuse connected in series in the circuit. In scenarios with transient current fluctuations, a brief circuit malfunction can cause the fast-blow fuse to blow, resulting in a permanent short circuit. Restoring the circuit requires replacing the fast-blow fuse, leading to poor overall battery pack stability and frequent fuse replacements. Before each replacement, the fault must be identified; otherwise, the fuse may blow again after replacement. This necessitates temporary power-on testing, which requires numerous auxiliary devices and is complex and inconvenient, hindering subsequent maintenance. Summary of the Invention

[0005] To address the problems existing in the prior art, the purpose of this invention is to provide a battery pack negative electrode overcharge safety protection structure with self-cut-off function, so as to solve the problems of poor battery pack stability, frequent replacement, and inconvenient maintenance caused by the current negative electrode fuse protection using only a single fast-blow fuse in series.

[0006] To solve the above problems, the present invention adopts the following technical solution.

[0007] A battery pack negative electrode overcharge safety protection structure with self-cutting function includes a protective shell. The protective shell has a cell slot and a device slot inside. Two rows of cell modules are fixedly installed inside the cell slot. A BMS control module, a fuse structure, and a mechanical circuit breaker module are installed inside the device slot. The fuse structure includes an insulating box, a one-time fuse, and a self-resetting fuse. The insulating box is fixedly installed between the BMS control module and the mechanical circuit breaker module. The one-time fuse is snap-fitted into the inside of the insulating box and electrically connected to the negative electrode of the battery and the mechanical circuit breaker module through wires. The self-resetting fuse is connected in series between the one-time fuse and the negative electrode of the cell module combined circuit. The disposable fuse includes an outer insulating shell and a fuse core. The outer insulating shell and the fuse core are fixedly installed inside the outer insulating shell and electrically connected to the external circuit wires. A one-way pressure valve is fixedly installed on the outside of the outer insulating shell. A conduit is threaded to the other end of the one-way pressure valve. The other end of the conduit is connected to the mechanical circuit breaker module. The mechanical circuit breaker module includes an insulating shell, an inner conductive post, a conductive sliding sleeve, a piston block, a T-shaped conductive post, a conductive copper sleeve, and an insulating spring. The insulating shell is fixedly installed inside the device slot. One end of the inner conductive post is connected to the disposable fuse core via a wire. The other end of the inner conductive post passes through and slides into the interior of the conductive sliding sleeve. The other end of the conductive sliding sleeve is fixedly connected to the piston block. One end of the T-shaped conductive post is fixedly connected to the piston block. The T-shaped end of the T-shaped conductive post is fixedly connected to the piston block. The other end of the T-shaped conductive post passes through and slides into the interior of the conductive copper sleeve. The other end of the conductive copper sleeve is connected to an external circuit connector via a wire. The end of the T-shaped conductive post inside the conductive copper sleeve is elastically connected to the interior of the conductive copper sleeve via an insulating spring.

[0008] As a further description of the above technical solution: the interior of the outer insulating shell is filled with high-pressure inert gas, and the end of the conduit away from the one-way pressure valve passes through and is fixedly connected to the interior of the insulating shell.

[0009] As a further description of the above technical solution: the inner conductive post includes a conductor segment and an insulating segment, the conductor segment and the insulating segment are fixedly connected at opposite ends, the insulating segment is located inside the conductive sliding sleeve, and the conductor segment is in contact with the conductive sliding sleeve and energized under normal conditions.

[0010] As a further description of the above technical solution: a thermal expansion sleeve is sleeved on the outside of the insulating section, and the thermal expansion sleeve shrinks back after cooling.

[0011] As a further description of the above technical solution: the side of the battery cell module is provided with a pressure relief valve, the side of the protective shell is provided with a downward exhaust groove, the outer end of the pressure relief valve is fixedly connected with a guide tube, and the other end of the guide tube passes through and is fixedly connected to the inside of the side groove.

[0012] As a further description of the above technical solution: two line connectors are installed on the right side of the protective shell, which are respectively connected to the BMS control module and the conductive copper sleeve.

[0013] As a further description of the above technical solution: the conductive copper sleeve has annularly distributed L-shaped through holes inside, the port inside the L-shaped through holes is connected to the cavity inside the conductive copper sleeve, and the L-shaped through holes are connected to the interior of the insulating shell.

[0014] As a further description of the above technical solution: the protective shell has reinforcing side plates on both sides that are parallel to the outer edge of the side groove.

[0015] Compared with the prior art, the advantages of this invention are: This solution uses a self-resetting fuse and a one-time fuse connected in series. It can respond to the overshoot abnormal circuit of the one-time fuse when the short-term instantaneous fluctuation fails to trigger the fuse, thus achieving temporary circuit breaker protection and avoiding frequent replacement of the one-time fuse. It can also respond in a timely manner to protect the battery cell module from power failure. This solution utilizes the high temperature generated by the fuse core when the fuse blows, and if it does not melt for a short time, the inert gas inside the fuse core fills the interior of the insulating shell, pushing the movable block to move. This causes the conductive sliding sleeve to move from the conductor section of the inner conductive post to the insulating section and be positioned, thus achieving mechanical circuit breaking. In addition to the above-mentioned dual protection, a third layer of protection is achieved, resulting in better safety. This solution temporarily connects the mechanical circuit breaker module with the self-resetting fuse to connect the circuit and verify whether the short circuit fault has been successfully eliminated. This avoids the waste and risk of the one-time fuse blowing again after installation if the fault has not been completely eliminated, and improves the convenience and accuracy of maintenance. Attached Figure Description

[0016] Figure 1 This is a top view cross-sectional structural diagram of the present invention; Figure 2 for Figure 1 Enlarged schematic diagram of section A in the middle; Figure 3 for Figure 1 Enlarged schematic diagram of section B in the middle; Figure 4 This is a partial top view cross-sectional structural schematic diagram of the present invention; Figure 5 This is a partial three-dimensional structural schematic diagram of the present invention; Figure 6 This is a side cross-sectional view of the conductive copper sleeve structure of the present invention; Explanation of the labels in the diagram: 1. Protective shell; 2. Cell slot; 3. Component slot; 4. Cell module; 41. Pressure relief valve; 42. Guide tube; 5. BMS control module; 6. Fuse structure; 61. Insulation box; 62. One-time fuse; 621. Outer insulation shell; 622. Fuse core; 623. One-way pressure valve; 624. Conduit; 63. Self-resetting fuse; 7. Mechanical circuit breaker module; 71. Insulation shell; 72. Inner conductive post; 721. Conductor section; 722. Insulation section; 723. Thermal expansion sleeve; 73. Conductive sliding sleeve; 74. Piston block; 75. T-shaped conductive post; 76. Conductive copper sleeve; 761. L-shaped through hole; 77. Insulating spring; 8. Side slot; 9. Line connector; 10. Reinforced side plate. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention; Please see Figure 1-6 In this invention, a battery pack negative electrode overcharge safety protection structure with self-cutting function includes a protective shell 1. The protective shell 1 has a cell slot 2 and a device slot 3 inside. Two rows of cell modules 4 are fixedly installed inside the cell slot 2. The device slot 3 has a BMS control module 5, a fuse structure 6 and a mechanical circuit breaking module 7 installed inside. The fuse structure 6 includes an insulating box 61, a one-time fuse 62 and a self-resetting fuse 63. The insulating box 61 is fixedly installed between the BMS control module 5 and the mechanical circuit breaking module 7. The one-time fuse 62 is snapped into the inside of the insulating box 61 and is electrically connected to the negative electrode of the battery and the mechanical circuit breaking module 7 through wires. The self-resetting fuse 63 is connected in series between the negative electrode of the one-time fuse 62 and the combined circuit of the cell module 4.

[0018] The one-time fuse 62 includes an outer insulating shell 621 and a fuse element 622. The outer insulating shell 621 and the fuse element 622 are fixedly installed inside the outer insulating shell 621 and electrically connected to the external circuit wires. A one-way pressure valve 623 is fixedly installed on the outside of the outer insulating shell 621. The other end of the one-way pressure valve 623 is threaded with a conduit 624. The other end of the conduit 624 is connected and cooperates with the mechanical circuit breaker module 7.

[0019] The mechanical circuit breaker module 7 includes an insulating housing 71, an inner conductive post 72, a conductive sliding sleeve 73, a piston block 74, a T-shaped conductive post 75, a conductive copper sleeve 76, and an insulating spring 77. The insulating housing 71 is fixedly installed inside the device slot 3. One end of the inner conductive post 72 is connected to the battery core of the disposable fuse 62 via a wire. The other end of the inner conductive post 72 passes through and slides into the interior of the conductive sliding sleeve 73. The other end of the conductive sliding sleeve 73 is fixedly connected to the piston block 74. One end of the T-shaped conductive post 75 is fixedly connected to the piston block 74. The T-shaped end of the T-shaped conductive post 75 is fixedly connected to the piston block 74. The other end of the T-shaped conductive post 75 passes through and slides into the interior of the conductive copper sleeve 76. The other end of the conductive copper sleeve 76 is connected to an external circuit connector via a wire. The end of the T-shaped conductive post 75 inside the conductive copper sleeve 76 is elastically connected to the interior of the conductive copper sleeve 76 via the insulating spring 77.

[0020] In this invention, the battery cell module 4 and the BMS control module 5 inside the battery cell slot 2 and the device slot 3 are protected by the protective shell 1. The BMS control module 5 controls the current and voltage of the battery cell module 4 to stabilize and realizes automatic overcharge protection. When the BMS control module 5 fails, the abnormal voltage generated by overcharge produces an abnormally large current that passes through the inside of the fuse structure 6.

[0021] If a brief current fluctuation occurs, the self-resetting fuse 63 will respond first, briefly breaking the circuit to protect the battery module 4 from overshoot damage. At this time, the one-time fuse 62 will not blow because the self-resetting fuse 63 will break the short circuit first. After a certain period of cooling, the self-resetting fuse 63 will restore the circuit, and the circuit will automatically recover. If the circuit fluctuation is continuous or a short circuit current occurs, the one-time fuse 62 will blow directly, completely breaking the circuit and avoiding overshoot thermal runaway. This avoids the problem of frequent replacement of the one-time fuse 62 caused by brief fluctuations and can also respond in a timely manner to protect the battery module 4 from power failure.

[0022] Furthermore, when the one-time fuse 62 melts, the fusible core 622 generates high temperature, causing the gas temperature and pressure inside the outer insulating shell 621 to rise, exceeding the pressure limit of the one-way pressure valve 623. At this time, the high-pressure gas breaks through the one-way pressure valve 623 and enters the interior of the insulating shell 71 along the conduit 624, causing the temperature and pressure in the space to the left of the piston block 74 to rise suddenly, pushing the piston block 74 to the right and causing the conductive sleeve 73 and the conductive copper sleeve 76 to move to the right synchronously. At this time, the conductive sleeve 73 slides to the right along the inner conductive post 72 to its insulating section. At this time, the insulating part of the inner conductive post 72 expands due to high temperature, locking the conductive sleeve 73. At this time, the T-shaped conductive post 75 slides inside the conductive copper sleeve 76, compressing the insulating spring 77. The resistance of the expanded insulating part to the conductive sleeve 73 is greater than the reaction force of the insulating spring 77, so that the conductive sleeve 73 is fixed, realizing synchronous mechanical cutting and achieving double protection. This structure can achieve mechanical cutting by using the generated high-temperature and high-pressure gas when the one-time fuse 62 is hot but not completely melted.

[0023] When replacing the disposable fuse 62, as the gas inside the insulating housing 71 cools and the expanded portion contracts, the insulating spring 77 pushes the conductive sleeve 73 to reset, allowing the mechanical circuit breaker module 7 to reconnect. At this point, it can be temporarily connected to the self-resetting fuse 63 to reconnect the circuit and verify whether the short circuit fault has been successfully eliminated. This avoids the disposable fuse 62 being installed after the fault has not been completely eliminated, which could cause it to blow again, resulting in waste and risk. It improves the convenience and accuracy of maintenance, thus enabling the device to protect the circuit using dual-type fuses set in series while reducing the replacement frequency of fast-blow fuses, improving overall stability, and facilitating the accuracy of subsequent troubleshooting. It also reduces the risk of further damage to fast-blow fuses, improving safety and convenience. This solves the problem in the prior art where a brief circuit malfunction can cause the fast-blow fuse to blow, resulting in a permanent short circuit. Restoration requires replacing the fast-blow fuse, leading to poor stability and frequent replacements. Furthermore, subsequent replacements require troubleshooting, which is not conducive to maintenance.

[0024] Please see Figure 1 The outer insulating shell 621 is filled with high-pressure inert gas, and the end of the conduit 624 away from the one-way pressure valve 623 passes through and is fixedly connected to the interior of the insulating shell 71.

[0025] In this invention, high-pressure inert gas is injected into the interior of the outer insulating shell 621, which not only provides better insulation protection for the fused core 622, but also ensures that the gas is in a more stable high-temperature and high-pressure state when it melts, thus avoiding the risk of combustion and improving overall safety.

[0026] Please see Figure 2The inner conductive post 72 includes a conductor segment 721 and an insulating segment 722. The conductor segment 721 and the insulating segment 722 are fixedly connected at opposite ends. The insulating segment 722 is located inside the conductive sliding sleeve 73. Under normal conditions, the conductor segment 721 is in contact with the conductive sliding sleeve 73 and is energized.

[0027] In this invention, the circuit is established by the contact between the conductor segment 721 and the conductive sleeve 73. As the conductive sleeve 73 is pushed by the high-pressure inert gas, it moves to contact the insulating segment 722, thereby achieving mechanical circuit breaking and providing dual protection.

[0028] Please see Figure 2 Among them, the outer side of the insulating section 722 is fitted with a thermal expansion sleeve 723, which shrinks back after cooling.

[0029] In this invention, the thermal expansion sleeve 723 expands rapidly after being heated by high-temperature gas, locking the conductive sliding sleeve 73 to achieve a mechanical short circuit. It can also self-recover after cooling. This function allows for temporary circuit protection when the current exceeds the limit of the self-resetting fuse 63 before the one-time fuse 62 reaches its breaking point and fails to function in time. The internal gas pressure is first heated to its limit, opening the one-way pressure valve 623. At this point, the one-time fuse 62 fails to disconnect the circuit in time, and high-pressure gas rushes into the insulating housing 71, pushing the conductive sliding sleeve 73 to achieve a temporary mechanical circuit break. It self-recovers after cooling.

[0030] Please see Figure 3 Among them: the side of the battery cell module 4 is provided with a pressure relief valve 41, the side of the protective shell 1 is provided with a downward exhaust groove 8, the outer end of the pressure relief valve 41 is fixedly connected with a guide tube 42, and the other end of the guide tube 42 passes through and is fixedly connected to the inside of the side groove 8.

[0031] In this invention, pressure relief is achieved by setting an independent guide tube 42 inside the guide side groove 8 of the pressure relief valve 41 of the battery cell module 4, which avoids the high temperature gas discharged during pressure relief from accumulating inside the protective shell 1, and at the same time reduces the impact of abnormal pressure relief of the battery cell module 4 on the battery cell module 4 with normal gas pressure.

[0032] Please see Figure 1 Among them, the right side of the protective shell 1 is equipped with two line connectors 9 that are respectively connected to the BMS control module 5 and the conductive copper sleeve 76.

[0033] In this invention, the line connector 9 facilitates connection to external lines and access to the charging line.

[0034] Please see Figure 1 and Figure 6The conductive copper sleeve 76 has annularly distributed L-shaped through holes 761 inside. The port inside the L-shaped through holes 761 is connected to the cavity inside the conductive copper sleeve 76, and the L-shaped through holes 761 are connected to the interior of the insulating shell 71.

[0035] In this invention, the L-shaped through hole 761 ensures that when the T-shaped conductive post 75 slides inside the conductive copper sleeve 76, the pressure inside the conductive copper sleeve 76 is always balanced with the outside, avoiding unnecessary resistance to the operation of the T-shaped conductive post 75, while improving the stability of the contact between the T-shaped conductive post 75 and its interior, ensuring normal passage.

[0036] Please see Figure 1 Among them, the protective shell 1 has reinforcing side plates 10 on both sides, which are parallel to the outer edge of the side groove 8.

[0037] In this invention, the reinforcing side plate 10 provided on the outside of the side groove 8 ensures the overall structural strength of the protective shell 1 and improves the protection effect on the battery cell module 4.

[0038] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A battery pack negative electrode overcharge safety protection structure with self-cut-off function, comprising a protective shell (1), wherein the protective shell (1) is provided with a cell slot (2) and a device slot (3), wherein two rows of sequentially arranged cell modules (4) are fixedly installed inside the cell slot (2), and a BMS control module (5), a fuse structure (6) and a mechanical circuit breaker module (7) are installed inside the device slot (3), characterized in that: The fuse structure (6) includes an insulating box (61), a disposable fuse (62), and a self-resetting fuse (63). The insulating box (61) is fixedly installed between the BMS control module (5) and the mechanical circuit breaker module (7). The disposable fuse (62) is snap-fitted into the interior of the insulating box (61) and electrically connected to the negative terminal of the battery and the mechanical circuit breaker module (7) via wires. The self-resetting fuse (63) is connected in series between the negative terminal of the disposable fuse (62) and the battery cell module (4) combined circuit. The disposable fuse (62) includes an outer insulating shell (621) and a fuse element (622). The outer insulating shell (621) and the fuse element (622) are fixedly installed inside the outer insulating shell (621) and electrically connected to the external circuit wires. A one-way pressure valve (623) is fixedly installed on the outside of the outer insulating shell (621). The other end of the one-way pressure valve (623) is threaded with a conduit (624). The other end of the conduit (624) is connected to the mechanical circuit breaker module (7). The mechanical circuit breaker module (7) includes an insulating shell (71), an inner conductive post (72), a conductive sleeve (73), a piston block (74), a T-shaped conductive post (75), a conductive copper sleeve (76), and an insulating spring (77). The insulating shell (71) is fixedly installed inside the device slot (3). One end of the inner conductive post (72) is connected to the core of a disposable fuse (62) via a wire. The other end of the inner conductive post (72) passes through and slides into the interior of the conductive sleeve (73). The other end of the conductive sleeve (73) is connected to... The piston block (74) is fixedly connected. One end of the T-shaped conductive post (75) is fixedly connected to the piston block (74). The T-shaped end of the T-shaped conductive post (75) is fixedly connected to the piston block (74). The other end of the T-shaped conductive post (75) passes through and slides into the interior of the conductive copper sleeve (76). The other end of the conductive copper sleeve (76) is connected to an external circuit connector through a wire. One end of the T-shaped conductive post (75) inside the conductive copper sleeve (76) is elastically connected to the interior of the conductive copper sleeve (76) through an insulating spring (77).

2. The battery pack negative electrode overcharge safety protection structure with self-cutoff function according to claim 1, characterized in that: The outer insulating shell (611) is filled with high-pressure inert gas, and the end of the conduit (614) away from the one-way pressure valve (623) passes through and is fixedly connected to the interior of the insulating shell (71).

3. The battery pack negative electrode overcharge safety protection structure with self-cutoff function according to claim 1, characterized in that: The inner conductive post (72) includes a conductor segment (721) and an insulating segment (722). The conductor segment (721) and the insulating segment (722) are fixedly connected at opposite ends. The insulating segment (722) is located inside the conductive sleeve (73). The conductor segment (721) is in contact with the conductive sleeve (73) and is energized under normal conditions.

4. The battery pack negative electrode overcharge safety protection structure with self-cut-off function according to claim 3, characterized in that: A thermal expansion sleeve (723) is fitted onto the outside of the insulating section (722), and the thermal expansion sleeve (723) shrinks back after cooling.

5. A battery pack negative electrode overcharge safety protection structure with self-cutoff function according to claim 1, characterized in that: The battery cell module (4) is provided with a pressure relief valve (41) on its side, and the protective shell (1) is provided with a downward exhaust groove (8) on its side. The outer end of the pressure relief valve (41) is fixedly connected to a guide tube (42), and the other end of the guide tube (42) passes through and is fixedly connected to the inside of the side groove (8).

6. The battery pack negative electrode overcharge safety protection structure with self-cutoff function according to claim 1, characterized in that: Two line connectors (9) are installed on the right side of the protective shell (1), which are respectively connected to the BMS control module (5) and the conductive copper sleeve (76).

7. A battery pack negative electrode overcharge safety protection structure with self-cutoff function according to claim 1, characterized in that: The conductive copper sleeve (76) has annularly distributed L-shaped through holes (761) inside. The port inside the L-shaped through hole (761) is connected to the cavity inside the conductive copper sleeve (76), and the L-shaped through hole (761) is connected to the interior of the insulating shell (71).

8. A battery pack negative electrode overcharge safety protection structure with self-cut-off function according to claim 5, characterized in that: The protective shell (1) has reinforcing side plates (10) on both sides, which are parallel to the outer edge of the side groove (8).

Images