A battery cover and battery

Abstract

This utility model discloses a fast-charging battery cover and battery with an integrated fast-fuse structure. The battery cover can be used for external short-circuit protection design of fast-charging batteries. It includes a cover base plate, an insulating component, a terminal post, a connecting piece, and a lower plastic layer. The terminal post and the connecting piece are integrally formed. The connecting piece has two fuse structures located outside the connection area between the terminal post and the connecting piece. The lower plastic layer is located below the connecting piece and between the two fuse structures. When an external short circuit occurs in the battery, the connecting piece melts instantly, isolating the battery core from the battery cover, thereby preventing further battery discharge and thermal runaway.

Description

Technical Field

[0001] This utility model belongs to the field of battery technology, and in particular relates to a battery cover and a battery. Background Technology

[0002] With the accelerated adoption of sodium-ion batteries in electric vehicles and large-scale energy storage, higher demands are being placed on their high-rate fast-charging performance. Especially under continuous charge and discharge conditions of 4C and above, the conductivity of internal current-carrying components (such as tabs and terminals) needs to be significantly improved. Therefore, increasing the tab width has become one of the key means to improve current-carrying capacity and reduce impedance-induced heat generation.

[0003] In existing battery cover structures, the current conduction path is typically "terminal post—connecting piece—tab," where the connecting piece and the tab are electrically connected by welding. As the tab width increases, the welding area between it and the connecting piece also increases to accommodate higher current transmission requirements. However, while this structure improves conductivity, it also introduces two prominent problems:

[0004] First, under fault conditions such as overcurrent or external short circuit, the cover plate assembly must have a fast-blowout protection function. Traditional solutions typically involve setting a localized fuse structure on the connecting piece to achieve circuit interruption. However, increasing the welding area may enhance the heat diffusion effect, making it difficult for the fuse zone to accumulate sufficient heat, thus affecting its fuse response speed and reliability, and posing a potential threat to the safety of the battery system.

[0005] Secondly, the increase in welding area also leads to an increase in structural size, which not only reduces the utilization rate of the battery's internal space but also increases the precision requirements of the assembly process.

[0006] Therefore, how to effectively avoid the heat sink effect caused by the increase in welding area while ensuring the high current overcurrent capacity, and ensure the rapid and reliable response of the fuse protection mechanism, has become an urgent problem to be solved. Utility Model Content

[0007] Based on the above analysis, this utility model aims to provide a battery cover and a battery, which solves at least one of the following technical problems: (1) the heat sink effect caused by the increase in welding area in the prior art makes it impossible for the fusion structure to fuse quickly and reliably; (2) the problem of reduced utilization of internal space of the battery and excessively high assembly precision requirements caused by the increase in welding area.

[0008] The objective of this utility model is mainly achieved through the following technical solutions:

[0009] This utility model provides a fast-charging battery cover plate with an integrated fast-fuse structure, including a cover plate substrate 3, an insulating component 5, an electrode post 6, a connecting piece 7, and a lower plastic 8;

[0010] The pole post 6 and the connecting piece 7 are integrally formed;

[0011] The connecting piece 7 includes a first connecting part 71 and a second connecting part 72, and a fusion structure 9 is provided between the first connecting part 71 and the second connecting part 72.

[0012] The lower plastic part 8 is located below the second connecting part 72.

[0013] Furthermore, there are two fusion structures 9, each of which includes grooves symmetrically formed on both sides of the width direction of the connecting piece 7.

[0014] Furthermore, the fast-charging battery cover also includes a terminal pressure plate 1, a resistance terminal 2, and a sealing ring 4.

[0015] Furthermore, the pole post 6 passes sequentially through the first through hole 14 on the insulating member 5, the second through hole 11 on the cover plate substrate 3, the sealing ring 4, and the third through hole 13 on the resistance terminal 2.

[0016] Furthermore, the pole plate 1 is fixedly connected to the upper end of the pole 6.

[0017] Furthermore, the cover plate substrate 3 is provided with an overlap edge 12 around its perimeter, and the overlap edge 12 is fixedly connected to the battery casing.

[0018] Furthermore, the cover plate substrate 3 is provided with a liquid injection hole 10, and the insulating component 5 is provided with a liquid injection through hole 15; the liquid injection through hole 15 and the liquid injection hole 10 are correspondingly arranged in a direction perpendicular to the thickness of the isolation plate 5.

[0019] Furthermore, the sealing ring 4 is located inside the second through hole 11 and is used to seal and isolate the pole post 6 from the cover plate substrate 3. The insulating member 5 is used to isolate the connecting piece 7 from the lower surface of the cover plate substrate 3. The resistance terminal 2 is used to isolate the pole post 6 from the upper surface of the cover plate substrate 3.

[0020] Furthermore, the lower plastic 8 and the connecting piece 7 are integrally formed.

[0021] Furthermore, the connecting portion of the connecting piece 7 is connected to the battery tab 18.

[0022] A second aspect of the present invention provides a battery including an electrode assembly, wherein the electrode assembly comprises a positive electrode, a negative electrode, and a separator stacked and spaced apart, the positive electrode and the negative electrode each comprising an electrode body and a tab 18 disposed on the edge of the electrode body, and further comprising the battery cover plate described in the first aspect, wherein the ratio of the width of the tab 18 to the width of the electrode body is greater than 0.9.

[0023] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0024] (1) The battery cover provided by this utility model integrates the electrode post and the connecting piece, and sets two fusion structures on the outside of the connection area between the electrode post and the connecting piece. This design can increase the laser welding area while avoiding the heat sink effect, and can also separate the core and the cover in time during external short circuit and overcurrent faults to ensure that the battery will not further run away from thermal runaway. Furthermore, by setting the welding position of the electrode tab and the connecting piece on the outside of the fusion structure, the welding area and heat dissipation area of ​​the connecting piece and the electrode tab are increased, which can improve the overcurrent performance of the electrode tab and the connecting piece.

[0025] (2) In this utility model, by integrally molding the electrode post and the connecting piece, the welding process between the electrode post and the connecting piece is eliminated, the assembly process is simplified, and the connection interface resistance is eliminated, thereby improving production efficiency and conductivity reliability.

[0026] (3) The present invention provides a lower plastic piece under the connecting piece and integrally molds it. When the fused structure is broken, the lower plastic piece can effectively isolate the electrode tab from contact with the inner side of the connecting piece, prevent the circuit from reconnecting, and realize permanent power-off protection under fault conditions.

[0027] Other features and advantages of this invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained by means of the structures particularly pointed out in the written description and the accompanying drawings. Attached Figure Description

[0028] The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0029] Figure 1 Exploded view of the battery cover;

[0030] Figure 2 This is a schematic diagram of the lower plastic part of the battery cover and the connecting piece.

[0031] Figure 3 This is a top view of the battery cover.

[0032] Figure 4 This is a schematic diagram showing the relationship between the tab width and the electrode width.

[0033] Figure 5 This is a schematic diagram of electrode tab welding;

[0034] Figure 6 A schematic diagram of the battery cover electrode structure (vertical direction);

[0035] Figure 7 This is a schematic diagram of the battery cover plate terminal structure (horizontal).

[0036] Figure Labels

[0037] 1. Terminal plate; 2. Resistance terminal; 3. Cover plate base plate; 4. Sealing ring; 5. Insulating component; 6. Terminal; 7. Connecting piece; 8. Lower plastic; 9. Fusible structure; 10. Injection hole; 11. Second through hole; 12. Overlap; 13. Third through hole; 14. First through hole; 15. Injection through hole; 16. Ultrasonic ear handle; 17. Welding area; 18. Electrode ear. Detailed Implementation

[0038] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0039] This utility model provides a fast-charging battery cover plate with an integrated fast-fuse structure, including a cover plate substrate 3, an insulating component 5, an electrode post 6, a connecting piece 7, and a lower plastic 8;

[0040] The connecting piece 7 includes a first connecting part 71 and a second connecting part 72, and a fusion structure 9 is provided between the first connecting part 71 and the second connecting part 72.

[0041] The lower plastic part 8 is located below the second connecting part 72.

[0042] In this utility model, such as Figure 1 , Figure 2 and Figure 3 As shown, the terminal post and connecting piece are integrated into a single design, and a fusion structure is provided between the first connecting part 71 and the second connecting part 72. This not only increases the laser welding area while avoiding the heat sink effect, but also promptly separates the core and cover plate in case of external short circuit and overcurrent fault, ensuring that the battery will not experience further thermal runaway. A lower plastic is provided below the second connecting part 72. When the battery experiences an external short circuit or fault, the fusion structure 9 of the connecting piece 7 melts, and due to the presence of the lower plastic 8, the electrical connection between the terminal post 6 and the tab 18 can be stably cut off, improving battery safety.

[0043] It is understood that the integral molding process involves forging, riveting, or welding to form a single component.

[0044] Furthermore, the integral molding of the electrode post 6 and the connecting piece 7 can help reduce battery assembly steps, thereby improving product yield.

[0045] According to some embodiments of this utility model, specifically, the cover plate substrate 3 is rectangular in shape with rounded corners at its four corners.

[0046] According to some embodiments of this utility model, specifically, the pole post 6 is cylindrical in shape, the connecting piece 7 is rectangular in shape, the four corners are rounded, and the length of the connecting piece 7 is less than the length of the cover plate substrate 3.

[0047] Understandably, the cover plate substrate 3 is formed by stamping.

[0048] It is understandable that the material of the lower plastic 8 is polyethylene or polyethylene terephthalate.

[0049] In this invention, the pole post 6 and the connecting piece 7 are each made of aluminum, copper, aluminum alloy or steel.

[0050] According to some embodiments of this utility model, specifically, each fusion structure 9 includes grooves symmetrically formed on both sides of the width direction of the connecting piece 7.

[0051] In this invention, a fusion structure 9 is formed by symmetrically opening double grooves on both sides of the connecting piece 7 in the width direction, which precisely defines the current path and the heat accumulation area. This symmetrical layout ensures synchronous melting of the double melting points in case of abnormal overcurrent, effectively avoiding the heat sink effect caused by the large welding area, while making the fracture process more balanced and the shape controllable, significantly improving the reliability and safety of the fusion protection.

[0052] According to some embodiments of this utility model, considering the structural stability of the pole 6 under internal and external forces, and achieving reliable isolation between the pole 6 and the cover plate substrate 3 through various insulating components (resistance terminal 2, sealing ring 4, insulating element 5), specifically, the fast charging battery cover plate also includes a pole pressure plate 1, a resistance terminal 2 and a sealing ring 4. The pole 6 passes sequentially through a first through hole 14 on the insulating element 5, a second through hole 11 on the cover plate substrate 3, the sealing ring 4 and a third through hole 13 on the resistance terminal 2. The pole pressure plate 1 is fixedly connected to the upper end of the pole 6.

[0053] In this invention, the electrode plate 1 is used to fix the electrode 6 and the resistance terminal 2.

[0054] It is understood that the pole plate 1 is made of aluminum, aluminum alloy or stainless steel.

[0055] It should be noted that when the electrode cover is used as the positive electrode cover of the battery, the resistance terminal 2 is made of plastic material with weak conductivity through injection molding. When the electrode cover is used as the negative electrode cover of the battery, the resistance terminal 2 is made of insulating plastic material through injection molding.

[0056] It is understandable that the sealing ring 4 and the insulating component 5 are made of insulating plastic material through injection molding.

[0057] According to some embodiments of the present invention, the cover plate substrate 3 is provided with an overlap edge 12 around its perimeter, and the overlap edge 12 is fixedly connected to the battery casing, for example by welding.

[0058] In this invention, the overlapping edge 12 can provide a stable and reliable welding interface, ensuring the final sealing of the battery casing.

[0059] Furthermore, the cover plate substrate 3 is provided with a liquid injection hole 10, and the insulating component 5 is provided with a liquid injection through hole 15; the liquid injection through hole 15 and the liquid injection hole 10 are correspondingly arranged in a direction perpendicular to the thickness of the isolation plate 5.

[0060] In this invention, the electrolyte injection through-hole 15 and the electrolyte injection hole 10 on the cover plate substrate 3 are correspondingly arranged in a direction perpendicular to the thickness of the separator 5, forming a continuous electrolyte injection channel. This ensures that the electrolyte can smoothly pass through the cover plate and be accurately injected into the battery, while maintaining the insulation and isolation function of the insulating component 5 to the connecting piece 7, thus taking into account both the characteristics of battery electrolyte injection process and internal insulation protection.

[0061] According to some embodiments of this utility model, considering the need to ensure the long-term sealing performance and electrical safety of the battery, the sealing ring 4 is located inside the second through hole 11 and is used to seal and isolate the terminal 6 from the cover plate substrate 3. The insulating member 5 is used to isolate the connecting piece 7 from the lower surface of the cover plate substrate 3, and the resistance terminal 2 is used to isolate the terminal 6 from the upper surface of the cover plate substrate 3.

[0062] According to some embodiments of this utility model, specifically, the lower plastic 8 is fixedly connected to the connecting piece 7.

[0063] In this invention, the lower plastic 8 and the connecting piece 7 can be connected by thermoplastic bonding. Preferably, the lower plastic 8 and the connecting piece 7 can be integrally molded, which can fundamentally eliminate the assembly gap between the lower plastic 8 and the connecting piece 7, ensuring the tightness and stability of their connection. This not only effectively supports the electrode tab and prevents displacement or reconnection after melting, but also simplifies the assembly process.

[0064] According to some embodiments of the present invention, the connecting portion 17 of the connecting piece 7 is connected to the battery tab 18.

[0065] In this invention, the connecting part 17 includes a first connecting part 71 and a second connecting part 72. The first connecting part 71 and the second connecting part 72 are respectively connected to the positive electrode tab and the negative electrode tab. This ensures that the welding area is large enough to meet the overcurrent requirements of high-rate charging and discharging, and successfully isolates the main welding heat sink area outside the fusion structure. This ensures that the fusion structure can quickly accumulate heat and melt in the event of a fault.

[0066] It should be noted that, as Figure 5 As shown, an ultrasonic earpiece 16 is also formed on the connecting part 17.

[0067] The second aspect of this utility model provides a battery, including an electrode assembly, wherein the electrode assembly is composed of multiple positive electrode plates, multiple negative electrode plates, and multiple separators stacked and spaced apart, that is, the electrode plates and separators are stacked to form a core assembly, and also includes the battery cover plate described in the first aspect.

[0068] In this utility model, the structures of the positive electrode and the negative electrode are as follows: Figure 4 As shown, it includes a tab and an electrode body. The tab is located on the edge of the electrode body. The ratio of the width of the tab to the width of the electrode is greater than 0.9. It can be seen that the tab and the electrode are basically aligned in the width direction, forming a large-area current conduction path.

[0069] In this invention, the wide tab or full tab is connected to the first connecting part 71 and the second connecting part 72 in the connecting piece 7. By increasing the width of the tab and welding on both sides of the connecting piece 7, the connection reliability between the adapter piece and the tab can be improved, and the tearing of the tab can be avoided. At the same time, welding the tab on both sides can effectively avoid the heat sink effect that occurs when there is an external short circuit or overcurrent abnormality.

[0070] It should be noted that the fusing mechanism of the battery cover provided by this utility model includes: when the battery experiences an external short circuit, the battery cover, acting as a current collector, needs to withstand an extremely large instantaneous discharge current (far exceeding the normal operating current) during the short circuit, according to Q=I 2 At point Rt, the battery heat dissipation increases, with a significant increase in heat dissipation at the battery cover. Simultaneously, the cross-sectional area of ​​the connecting piece 7 changes abruptly at the groove, resulting in a higher resistance at the groove compared to its normal position. This leads to a sharp increase in current density at the groove, causing more severe localized heating. Furthermore, the heat dissipation path at the groove is restricted, making heat accumulation easier. When the heat reaches a certain level, the connecting piece melts at the groove. Since the current flowing through both melted points of the connecting piece 7 is the same, the heat generated at the two melted points is comparable. Therefore, when one melts, the other will melt simultaneously. After the melting at the groove of the connecting piece, the winding core is disconnected from the terminal post 6, creating an open circuit in the battery. This stops the external short circuit and prevents further temperature increases that could lead to thermal runaway.

[0071] According to a specific embodiment of the present invention, in the battery cover plate, the terminal post 6 first passes through the first through hole 14 of the insulating member 5, and is isolated from the connecting piece 7 and the lower surface of the cover plate substrate 3 by the insulating member 5. Then, the terminal post 6 passes through the second through hole 11 on the cover plate substrate 3, and the sealing ring 4 is disposed in the second through hole 11 on the cover plate substrate 3. The sealing ring 4 is used to fix and isolate the terminal post 6 from the cover plate substrate 3. Finally, the terminal post 6 passes through the third through hole 13 on the resistance terminal 2, and is isolated from the upper surface of the cover plate substrate 3 by the resistance terminal 2. The terminal post pressure plate 1 is provided with a pressure plate positioning hole corresponding to the position of the upper surface of the terminal post 6. The upper surface of the cylindrical part of the terminal post passes through the terminal post pressure plate positioning hole. The terminal post pressure plate 1 and the terminal post 6 are fixedly connected by laser welding.

[0072] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model should be included within the protection scope of the present utility model.

Claims

1. A battery cover, characterized in that, It includes a cover plate substrate (3), an insulating component (5), an electrode post (6), a connecting piece (7), and a lower plastic piece (8); The pole post (6) and the connecting piece (7) are integrally formed; The connecting piece (7) includes a first connecting part (71) and a second connecting part (72), and a fusion structure (9) is provided between the first connecting part (71) and the second connecting part (72); The lower plastic (8) is disposed below the second connecting part (72).

2. The battery cover according to claim 1, characterized in that, The fusion structure (9) includes grooves symmetrically formed on both sides of the connecting piece (7) in the width direction.

3. The battery cover according to claim 2, characterized in that, The battery cover also includes a terminal pressure plate (1), a resistance terminal (2), and a sealing ring (4); The pole (6) passes sequentially through the first through hole (14) on the insulating member (5), the second through hole (11) on the cover plate substrate (3), the sealing ring (4), and the third through hole (13) on the resistance terminal (2).

4. The battery cover according to claim 1, characterized in that, The cover plate substrate (3) has an overlap (12) around its perimeter, and the overlap (12) is fixedly connected to the battery casing.

5. The battery cover according to claim 3, characterized in that, The pole plate (1) is fixedly connected to the upper end of the pole (6).

6. The battery cover according to claim 3, characterized in that, The cover plate substrate (3) is provided with a liquid injection hole (10), and the insulating component (5) is provided with a liquid injection through hole (15); the liquid injection through hole (15) and the liquid injection hole (10) are provided in a direction perpendicular to the thickness of the insulating component (5).

7. The battery cover according to claim 3, characterized in that, The sealing ring (4) is located inside the second through hole (11) and is used to seal and isolate the pole post (6) from the cover plate substrate (3). The insulating member (5) is used to isolate the connecting piece (7) from the lower surface of the cover plate substrate (3). The resistance terminal (2) is used to isolate the pole post (6) from the upper surface of the cover plate substrate (3).

8. The battery cover according to claim 1, characterized in that, The lower plastic (8) and the connecting piece (7) are integrally formed.

9. The battery cover according to claim 4, characterized in that, The connecting part of the connecting piece (7) is connected to the battery tab (18).

10. A battery, characterized in that, The battery includes an electrode assembly, wherein the electrode assembly is composed of a positive electrode, a negative electrode, and a separator stacked and spaced apart. The positive electrode and the negative electrode include an electrode body and a tab (18) disposed on the edge of the electrode body. The battery also includes a battery cover plate as described in any one of claims 1-9, wherein the ratio of the width of the tab (18) to the width of the electrode body is greater than 0.9.

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