High-safety power battery with fuse and PTC (Positive Temperature Coefficient) connected in series for use

Abstract

The utility model discloses a high-safety power battery with a fuse and a PTC (Positive Temperature Coefficient) connected in series for use, which particularly relates to the technical field of power batteries and comprises a shell, an upper pole is fixedly connected to the upper side of the shell, a lower pole is fixedly connected to the lower side of the shell, and a lower conducting strip is fixedly connected to the bottom wall of the inner surface of the shell. The lower end of the upper pole penetrates through the upper side of the shell and is fixedly connected with a fuse, and the inner surface of the shell is fixedly connected with two cut-off assemblies. According to the high-safety power battery with the fuse and the PTC in series connection for use, the fuse can be quickly cut off by arranging the cut-off assembly after a battery circuit is short-circuited, high temperature and electric arcs are prevented from being generated in the battery, so that the risk of a fire disaster is reduced, and the fuse, the PTC plate and the cut-off assembly are arranged to perform multiple protection on the battery circuit, so that the service life of the battery is prolonged. Triple protection mechanisms are mutually independent and work cooperatively, comprehensive safety guarantee is provided for the circuit, and the stability of the system is improved.

Description

Technical Field

[0001] This utility model relates to the field of power battery technology, and in particular to a high-safety power battery using a fuse and a PTC connected in series. Background Technology

[0002] The new energy industry has excellent development prospects. Lithium-ion batteries are a type of lithium-ion power battery with high energy density and good safety performance, and are widely used in new energy electric vehicles.

[0003] In the application of lithium-ion power batteries, short circuits may occur. When a lithium-ion power battery short circuits, as the internal temperature of the battery accumulates too high, the internal components of the battery may be damaged or even melted. It may also generate sparks that directly ignite the electrolyte, causing the entire battery to burn and resulting in a fire. At the same time, the increase in internal temperature increases the internal pressure, which also poses a risk of battery explosion. Therefore, it is necessary to set up protective structures for lithium power batteries to avoid risks such as explosion and fire.

[0004] Existing lithium-ion power batteries typically protect the circuit by using fuses. When the current exceeds a certain threshold, the fuse will melt, thus cutting off the circuit and preventing excessive current from damaging the circuit and equipment. However, fuses are mostly made of aluminum wire, copper wire, or alloy wire. These materials generally have good toughness and still require a certain amount of time to melt after a short circuit. Furthermore, when a fuse melts due to overcurrent, the instantaneous interruption of current and sudden change in voltage may generate an electric arc at the connection between the fuse and the circuit, thereby damaging circuit components and causing fires. Utility Model Content

[0005] The main purpose of this invention is to provide a high-safety power battery that uses a fuse and a PTC in series, which can effectively solve the problem that the fuse cannot melt quickly after a short circuit in a lithium-ion power battery.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A high-safety power battery using a fuse and a PTC connected in series includes a casing. An upper terminal post is fixedly connected to the upper side of the casing, and a lower terminal post is fixedly connected to the lower side of the casing. A busbar is fixedly connected to the lower terminal post. A lower conductive plate is fixedly connected to the bottom wall of the inner surface of the casing. A PTC plate is fixedly connected to the upper end of the lower conductive plate. An upper conductive plate is fixedly connected to the upper end of the PTC plate. The lower end of the upper terminal post passes through the upper side of the casing and is fixedly connected to a fuse. The lower end of the fuse is fixedly connected to the upper end of the upper conductive plate. Two cutting components are fixedly connected to the inner surface of the casing. The upper end of the lower terminal post passes through the lower side of the casing and is fixedly connected to the lower conductive plate. A winding core is fixedly connected to the lower side of the busbar.

[0008] Preferably, the fuse is U-shaped.

[0009] Preferably, the two cutting components are respectively located on both sides of the bend in the fuse and are arranged symmetrically.

[0010] Preferably, the cutting assembly includes a vertical plate fixedly connected to the inner surface of the housing, two horizontal plates fixedly connected to the end of the vertical plate that is close to the fuse, a bracket fixedly connected to the end of the two horizontal plates that is close to the fuse, a support plate fixedly connected to the middle of the middle of the end of the two horizontal plates that is close to each other, an expansion column slidably connected to the middle of the support plate, a spring fixedly connected to the expansion column and the horizontal plates, and a cutting blade fixedly connected to the end of the expansion column that is far from the spring.

[0011] Preferably, the cutting blade is slidably connected to the bracket.

[0012] Preferably, both sides of the upper end of the housing are fixedly connected to fasteners, and the lower ends of the two fasteners pass through the housing, the upper conductive sheet, the PTC plate and the lower conductive sheet in sequence.

[0013] Preferably, the cutting blade is a ceramic blade.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. By setting up a cut-off component, this utility model can quickly cut off the fuse and interrupt the current after the battery circuit is short-circuited or the temperature rises, thereby preventing the generation of high temperature and electric arc inside the battery, reducing the risk of fire and explosion, avoiding damage to the battery pack caused by short circuit or high temperature, and extending the service life of the battery pack.

[0016] 2. This utility model provides multiple protections for the lithium-ion battery circuit by setting up a fuse, a PTC board, and a cut-off component. The three protection mechanisms are independent of each other but work together to provide comprehensive safety for the circuit. Even if one protection mechanism fails, the other mechanisms can still continue to function, ensuring the safe operation of the battery pack and improving the stability and reliability of the system. Attached Figure Description

[0017] Figure 1 This is a cross-sectional structural diagram of the present invention;

[0018] Figure 2 for Figure 1 Enlarged view of point A in the middle.

[0019] In the diagram: 1. Housing; 2. Upper electrode post; 3. Lower electrode post; 4. Busbar; 5. Upper conductive plate; 6. PTC board; 7. Lower conductive plate; 8. Fuse; 9. Cut-off assembly; 91. Vertical plate; 92. Horizontal plate; 93. Bracket; 94. Support plate; 95. Expansion column; 96. Spring; 97. Cutting disc; 10. Fixing component. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0021] Example 1

[0022] like Figure 1 As shown, a high-safety power battery using a fuse and a PTC connected in series includes a housing 1. An upper terminal post 2 is fixedly connected to the upper side of the housing 1, a lower terminal post 3 is fixedly connected to the lower side of the housing 1, a busbar 4 is fixedly connected to the lower terminal post 3, a lower conductive sheet 7 is fixedly connected to the bottom wall of the inner surface of the housing 1, a PTC plate 6 is fixedly connected to the upper end of the lower conductive sheet 7, an upper conductive sheet 5 is fixedly connected to the upper end of the PTC plate 6, the lower end of the upper terminal post 2 passes through the upper side of the housing 1 and is fixedly connected to a fuse 8, the lower end of the fuse 8 is fixedly connected to the upper end of the upper conductive sheet 5, two cutting components 9 are fixedly connected to the inner surface of the housing 1, the upper end of the lower terminal post 3 passes through the lower side of the housing 1 and is fixedly connected to the lower conductive sheet 7, and a winding core is fixedly connected to the lower side of the busbar 4.

[0023] The aforementioned core, together with the other structures in this case, constitutes the main body of the power battery. During implementation, a corresponding outer casing can be designed and manufactured for the aforementioned structure.

[0024] PTC is short for Positive Temperature Coefficient Thermistor. It is a material or component with special electrical properties. The resistance of a PTC thermistor increases with increasing temperature. When the temperature rises, the grain boundary resistance inside the PTC material increases, resulting in an increase in the overall resistance. This change is reversible, that is, when the temperature decreases, the resistance will decrease accordingly.

[0025] In this embodiment, the PTC board 6 is a PTC with a polymer structure that is welded with nickel-plated copper foil on both sides. Considering that the battery will be in a high-temperature state under abnormal conditions such as short circuit, it is designed to be placed outside the end cap of the lithium power battery and connected in series in the circuit. This design can effectively reduce the impact of the high-temperature PTC board 6 on the internal materials and structure of the battery and is conducive to heat dissipation. As a circuit protection element, the fuse 8 and the PTC board 6 have very low internal resistance and low loss, and do not affect the battery internal resistance and the normal operation of the battery circuit.

[0026] When an overcurrent occurs inside the lithium-ion battery, the PTC board 6 will continuously increase its temperature to a certain set value under the action of the abnormal current. At this time, the internal resistance of the PTC board 6 increases stepwise, which significantly reduces the current in the battery circuit, thereby protecting the battery. After the battery is repaired and passes through the normal current again, the PTC board 6 returns to a low resistance and low power consumption state, and the battery can be used normally again.

[0027] When the battery current is between 0-80A, the resistance of PTC board 6 is small, not exceeding 0.5mΩ, and the temperature change of PTC board 6 is Δt≤20℃, so the battery can be used normally. When the battery malfunctions, it will trigger an action with an action current range of 100A-160A. PTC board 6 will heat up continuously in a short time, generally not exceeding 120℃, and the resistance will increase sharply. At the same time, the current in the circuit will drop rapidly to less than one-tenth of the previous value, preventing the large current from damaging the battery.

[0028] Once the battery malfunction is resolved, when the battery is passed through a current not exceeding 0-80A again, the PTC plate 6 will return to a resistance value below 0.5mΩ, and the battery can continue to be used normally. In addition, the PTC design is located on the outside of the end cap, which not only saves internal space of the battery and increases energy density, but also ensures that the high temperature of the PTC plate 6 will not damage other internal components of the battery or affect the electrolyte when the battery malfunctions.

[0029] Fuse 8 is a nickel-plated copper fuse with a thickness of 0.4-0.6mm. Fuse 8 is U-shaped. After being processed and bent, fuse 8 is welded to the battery terminals on both sides, so that it is connected in series in the battery circuit to protect the battery from overcurrent. When the current is too high, fuse 8 will melt to prevent smoke or even fire caused by excessive current.

[0030] Fuse 8 is a single-use item. Once it blows, the circuit is in an open state and cannot be restored. The breaking current of fuse 8 is higher than that of PTC board 6, and its protection action occurs after that of PTC board 6. Together with PTC board 6, they provide dual protection for the battery.

[0031] In this embodiment, the busbar 4 is fixedly connected to one discharge terminal of the lithium-ion power battery. During the use of the lithium-ion power battery, the current flows sequentially through the upper electrode 2, fuse 8, upper conductive sheet 5, PTC plate 6, lower conductive sheet 7, lower electrode 3 and busbar 4, and finally flows to the discharge terminal of the lithium-ion power battery fixedly connected to the busbar 4.

[0032] This embodiment, by setting up a PTC board 6 and a fuse 8, can prevent safety problems such as battery leakage, fire, and explosion caused by high temperature or high voltage due to internal short circuits, overcurrent charging and discharging.

[0033] Example 2

[0034] Based on Embodiment 1, this embodiment adds a cutting-off component 9, which is used to quickly cut off the fuse 8 after a short circuit occurs in the lithium-ion power battery, so as to avoid generating an electric arc and causing a fire.

[0035] like Figure 2 As shown, the cutting assembly 9 includes a vertical plate 91 fixedly connected to the inner surface of the housing 1. Two horizontal plates 92 are fixedly connected to the end of the vertical plate 91 that is close to the fuse 8. A bracket 93 is fixedly connected to the end of the two horizontal plates 92 that is close to the fuse 8. A support plate 94 is fixedly connected to the middle of the end of the two horizontal plates 92 that is close to each other. An expansion column 95 is slidably connected to the middle of the support plate 94. A spring 96 is fixedly connected to the expansion column 95 and the horizontal plate 92. A cutting blade 97 is fixedly connected to the end of the expansion column 95 that is far away from the spring 96.

[0036] For details, please refer to Figure 1 The cutting blade 97 is a ceramic blade.

[0037] For details, please refer to Figure 1 Two cutting components 9 are respectively located on both sides of the bend of the fuse 8 and are arranged symmetrically.

[0038] The expansion column 95 uses a heat-expanding polymer from existing technologies. Common polymers include expanded polystyrene, expanded polyamide, and expanded polypropylene. In practical applications, the appropriate material can be selected based on the normal operating temperature range of the fuse 8 and the PTC board 6.

[0039] Furthermore, such as Figure 2 As shown, the cutting blade 97 is slidably connected to the bracket 93. The bracket 93 can restrict the sliding direction of the cutting blade 97 to ensure that the cutting blade 97 can slide towards the bend of the fuse 8. Because the bend of the fuse 8 is a stress concentration point, when subjected to external force or temperature change, the bend will bear greater stress and strain, and is more likely to break.

[0040] In its natural state, spring 96 is in a stretched state. Spring 96 pulls expansion column 95 to prevent cutting disc 97 from sliding towards fuse 8 and damaging fuse 8 during normal use.

[0041] like Figure 1 As shown, two fixing members 10 are fixedly connected to the upper ends of the housing 1 on both sides. The lower ends of the two fixing members 10 pass through the housing 1, the upper conductive sheet 5, the PTC plate 6 and the lower conductive sheet 7 in sequence.

[0042] In this embodiment, when a short circuit occurs and an overcurrent is generated, a large amount of heat is produced, causing the circuit temperature to rise rapidly. At the same time, the PTC board 6 will also heat up continuously in a short period of time, and its resistance will increase, causing the current in the circuit to drop rapidly, preventing the large current from damaging the battery. When the battery abnormality is resolved, the PTC board 6 will return to a resistance value of less than 0.5mΩ, and the lithium-ion power battery can continue to be used normally.

[0043] When a short circuit occurs in the circuit and an overcurrent is generated, and the current increases to exceed the current range that the PTC board 6 can withstand, the fuse 8 will play a role. When the fuse 8 is working normally, the ambient temperature is between -40℃ and 125℃. Under the rated current, the fuse 8 will gradually melt after working for at least four hours. When the circuit current exceeds twice the rated current of the fuse 8, the fuse 8 will melt within a few seconds, thus playing a role in circuit protection.

[0044] However, during the process of fuse 8 blowing, an electric arc may be generated at the connection between fuse 8 and the circuit. To ensure circuit safety, after the PTC board 6 fails, fuse 8 needs to be cut off as soon as possible. When the circuit temperature exceeds the normal operating temperature of fuse 8, the expansion column 95 gradually expands due to heat. The support plate 94 will restrict the expansion column 95 in the axial direction, but the thermal stress inside the expansion column 95 causes it to expand in the radial direction. The expanded expansion column 95 pushes the cutting blade 97 to move towards fuse 8. The two cutting blades 97 together clamp the bend of fuse 8 and quickly cut off fuse 8.

[0045] It should be noted that the specific installation methods, circuit connection methods, and control methods of the busbar 4, PTC board 6, and fuse 8 used in this utility model are all conventional designs, and will not be described in detail in this utility model.

[0046] The working principle of this utility model is as follows: First, the busbar 4 is fixedly connected to one discharge terminal of the lithium-ion power battery. During the use of the lithium-ion power battery, the current flows sequentially through the upper electrode 2, fuse 8, upper conductive sheet 5, PTC plate 6, lower conductive sheet 7, lower electrode 3 and busbar 4, and finally flows to the discharge terminal of the lithium-ion power battery fixedly connected to the busbar 4.

[0047] When a short circuit occurs in the circuit and an overcurrent is generated, a large amount of heat is produced, causing the circuit temperature to rise rapidly. At the same time, the PTC board 6 will also heat up continuously in a short period of time, and its resistance will increase, causing the current in the circuit to drop rapidly, preventing the large current from damaging the battery. When the battery abnormality is resolved, the PTC board 6 will return to a resistance value of less than 0.5mΩ, and the lithium-ion power battery can continue to be used normally.

[0048] When a short circuit occurs in the circuit and an overcurrent is generated, and the current increases to exceed the current range that the PTC board 6 can withstand, the fuse 8 will play a role. When the fuse 8 is working normally, the ambient temperature is between -40℃ and 125℃. Under the rated current, the fuse 8 will gradually melt after working for at least four hours. When the circuit current exceeds twice the rated current of the fuse 8, the fuse 8 will melt within a few seconds, thus playing a role in circuit protection.

[0049] However, during the process of fuse 8 blowing, an electric arc may be generated at the connection between fuse 8 and the circuit. To ensure circuit safety, after the PTC board 6 fails, fuse 8 needs to be cut off as soon as possible. When the circuit temperature exceeds the normal operating temperature of fuse 8, the expansion column 95 gradually expands due to heat. The support plate 94 will restrict the expansion column 95 in the axial direction, but the thermal stress inside the expansion column 95 causes it to expand in the radial direction. The expanded expansion column 95 pushes the cutting blade 97 to move towards fuse 8. The two cutting blades 97 together clamp the bend of fuse 8 and quickly cut off fuse 8.

[0050] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A high safety power battery using a fuse and a PTC in series, comprising a shell (1), characterized in that: The upper pole column (2) is fixedly connected to the upper side of the shell (1), the lower pole column (3) is fixedly connected to the lower side of the shell (1), the bus bar (4) is fixedly connected to the lower pole column (3), the lower conductive sheet (7) is fixedly connected to the bottom wall of the inner surface of the shell (1), the PTC plate (6) is fixedly connected to the upper end of the lower conductive sheet (7), the upper conductive sheet (5) is fixedly connected to the upper end of the PTC plate (6), the fuse (8) is fixedly connected to the upper end of the upper pole column (2) and penetrates the upper side of the shell (1), the lower end of the fuse (8) is fixedly connected to the upper end of the upper conductive sheet (5), two cut-off assemblies (9) are fixedly connected to the inner surface of the shell (1), the lower end of the lower pole column (3) penetrates the lower side of the shell (1) and is fixedly connected to the lower conductive sheet (7), and the winding core is fixedly connected to the lower side of the bus bar (4).

2. The high safety power battery with series connection of fuse and PTC according to claim 1, characterized in that: The fuse (8) is in U shape.

3. A high-safety power battery using a fuse and a PTC connected in series according to claim 1, characterized in that: The two cut-off assemblies (9) are respectively arranged on the two sides of the bending part of the fuse (8) and are symmetrically arranged.

4. A high-safety power battery using a fuse and a PTC connected in series according to claim 1, characterized in that: The cut-off assembly (9) comprises a vertical plate (91) fixedly connected to the inner surface of the shell (1), two horizontal plates (92) fixedly connected to one end of the vertical plate (91) and close to the fuse (8), a support (93) fixedly connected to the ends of the two horizontal plates (92) and close to each other, a support plate (94) fixedly connected to the middle of the ends of the two horizontal plates (92) and close to each other, an expansion column (95) slidably connected to the middle of the support plate (94), a spring (96) fixedly connected to the expansion column (95) and the horizontal plate (92), and a cutting sheet (97) fixedly connected to one end of the expansion column (95) and away from the spring (96).

5. A high-safety power battery using a fuse and a PTC connected in series according to claim 4, characterized in that: The cutting sheet (97) is slidably connected to the support (93).

6. The high safety power battery of claim 1, wherein: the fuse and the PTC are connected in series. The upper end of the shell (1) is fixedly connected with a fixing piece (10), and the lower end of the fixing piece (10) penetrates the shell (1), the upper conductive sheet (5), the PTC plate (6) and the lower conductive sheet (7) in sequence.

7. The high safety power battery of claim 4, wherein: the fuse is connected in series with the PTC. The cutting sheet (97) is a ceramic blade.

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