EXPLODE-PROOF VALVE, BATTERY COVER AND BATTERY

Abstract

The present application discloses an explosion-proof valve, a battery cover, and a battery. The explosion-proof valve is provided with an annular groove; the annular groove divides the explosion-proof valve into a breaking part and a fixing part; one side of the breaking part is recessed to form an arc-shaped pressure bearing recess, and the bottom of the pressure bearing recess is located within the annular groove.

Description

Explosion-proof valve, battery cover and battery

[0001] This application claims priority to Chinese patent application filed on February 10, 2022, with application number 202220271615.8, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of battery technology, for example, to an explosion-proof valve, a battery cover and a battery. Background Art

[0003] As lithium-ion battery technology matures, it's widely used as a power source in electric vehicles. Overcharging a battery generates gas, increasing internal pressure. To prevent explosion, a battery explosion-proof valve is typically installed on the battery cover or the bottom of the battery housing.

[0004] However, when the battery is overcharged and a large amount of gas is generated, causing the internal pressure to increase, the gas pressure on the side of the explosion-proof valve facing the interior of the battery is equal everywhere, making the rupture position of the explosion-proof valve difficult to predict. This makes the situation uncontrollable when the explosion-proof valve ruptures, which is prone to danger.

[0005] Summary of the Invention

[0006] The present application proposes an explosion-proof valve, a battery cover, and a battery, which can control the rupture position when subjected to gas pressure, thereby improving safety.

[0007] In the first aspect, an embodiment of the present application provides an explosion-proof valve, which is provided with an annular groove, and the annular groove divides the explosion-proof valve into a rupture part and a fixed part. An arc-shaped pressure-bearing groove is recessed on one side of the rupture part, and the bottom of the pressure-bearing groove is located within the annular groove.

[0008] In one embodiment, the explosion-proof valve is provided with a liquid injection hole.

[0009] In one embodiment, the explosion-proof valve is provided with a blocking groove, and the injection hole is provided at the bottom of the blocking groove.

[0010] In one embodiment, the bottom of the annular groove is provided with notches.

[0011] In one embodiment, the width of the notch gradually decreases from the notch opening to the bottom of the annular groove.

[0012] In one embodiment, the notch extends along the circumference of the annular groove.

[0013] In one embodiment, the explosion-proof valve is made of metal material.

[0014] A battery cover plate comprises the explosion-proof valve and a top cover, wherein the explosion-proof valve is arranged on the top cover.

[0015] In one embodiment, a first insulating member is further included, wherein the first insulating member is detachably connected to the top cover and is located between the top cover and the battery housing.

[0016] In one embodiment, one of the first insulating member and the top cover is provided with a first positioning post, and the other is provided with a first positioning hole, and the first positioning post is inserted into the first positioning hole.

[0017] In a second aspect, an embodiment of the present application provides a battery, comprising the above-mentioned battery cover and battery housing, wherein the battery housing is provided with a mounting hole, and the battery cover is buckled into the battery housing to close the mounting hole.

[0018] Beneficial effects of this application:

[0019] The present application provides an explosion-proof valve, a battery cover, and a battery. The explosion-proof valve reduces its own strength by providing an annular groove. Since the thickness of the annular groove is relatively small, the explosion-proof valve is more likely to rupture at the annular groove and release pressure when subjected to gas impact. At the same time, the pressure-bearing groove of the rupture portion is provided on the side facing the interior of the battery. When the gas inside the battery impacts the explosion-proof valve, more gas is gathered at the pressure-bearing groove, and the arc surface of the pressure-bearing groove has a larger area than the flat surface, so that the gas pressure at the pressure-bearing groove is greater and more concentrated, resulting in the rupture portion being subjected to greater pressure than the fixed portion, further causing the explosion-proof valve to rupture preferentially from the annular groove. The explosion-proof valve can rupture at the annular groove when subjected to gas pressure, and the rupture position is controllable, thereby improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is an exploded view of a battery cover provided in an embodiment of the present application;

[0021] FIG2 is a cross-sectional view of a battery cover provided in an embodiment of the present application;

[0022] FIG3 is a schematic structural diagram of an explosion-proof valve provided in an embodiment of the present application;

[0023] FIG4 is a cross-sectional view of an explosion-proof valve provided in an embodiment of the present application.

[0024] In the picture:

[0025] 1. Explosion-proof valve; 2. Top cover; 3. Pole; 4. Collector plate; 5. First insulating member; 6. Sealing ring; 7. Terminal; 8. Second insulating member;

[0026] 11. Liquid injection hole; 12. Annular groove; 13. Rupture portion; 14. Fixing portion; 15. Pressure-bearing groove; 16. Blocking groove; 51. First positioning post; 81. Second positioning post;

[0027] 121. Notch. DETAILED DESCRIPTION

[0028] In the description of this application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limitations on this application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions.

[0029] Unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," and "fixed" should be interpreted broadly. For example, they may refer to fixed or removable connections; mechanical or electrical connections; direct or indirect connections through an intermediary; and internal communication between two components or interactions between two components. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0030] Unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in contact with the second feature through another feature between them instead of being in direct contact. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0031] The technical solution of the present application will be further explained below with reference to the accompanying drawings and through specific implementation methods.

[0032] This embodiment provides a battery. The battery is a lithium-ion battery and includes a positive electrode, a negative electrode, a separator, and an electrolyte. The separator is configured to separate the positive electrode from the negative electrode to prevent short circuits and allows lithium ions to pass through. In the manufacturing process of lithium-ion batteries, a winding process is often used, in which the positive electrode, separator, and negative electrode are stacked in this order and then wound to form a wound structure. After winding, the wound structure is placed in a battery casing and the electrolyte is injected to form a complete battery.

[0033] The battery consists of a battery housing and a battery cover. The battery housing has a mounting hole, and the battery cover snaps onto the battery housing to seal the mounting hole. The removable battery cover makes it easy for operators to insert the positive electrode, negative electrode, separator, and electrolyte into the battery housing through the mounting hole. It also facilitates subsequent disassembly and recycling of the battery, reducing battery costs throughout its entire life cycle.

[0034] Exemplarily, as shown in FIG1 , the battery cover includes a top cover 2 , which is configured to be buckled into the battery housing to form a closed structure.

[0035] For example, as shown in Figures 1 and 2, the battery cover includes a terminal 3, a first end of which is fixed to the top cover 2, and a second end of which passes through and extends out of the top cover 2. The terminal 3 is connected to the positive pole of the battery, and the battery casing is connected to the negative pole of the battery, so that the positive and negative poles of the battery can be connected to an external circuit.

[0036] When the battery needs to discharge at a high rate (above 3C), the thermal effect of the current is obvious, which can easily cause local heating of the battery's tabs, leading to battery expansion, and thus danger. To solve this problem, the battery cover also includes a current collecting plate 4, and the pole 3 passes through the current collecting plate 4 and is electrically connected to the current collecting plate 4. The positive electrode of the wound structure extends from one end, and the negative electrode of the wound structure extends from the other end. The positive and negative electrodes of the wound structure are multi-layer structures, and the multi-layer positive electrodes are electrically connected to the current collecting plate 4, and the multi-layer negative electrodes are electrically connected to the battery casing, so that the battery forms a full-tab structure, which greatly reduces the thermal effect generated by the battery during high-rate discharge and can disperse the heat, thereby improving the safety performance of the battery.

[0037] Since the top cover 2 is mostly made of metal, to prevent short circuits, the battery cover also includes a first insulating member 5. This first insulating member 5 is detachably connected to the top cover 2 and located between the top cover 2 and the battery casing. The battery cover cannot be charged to ensure a safe distance between the positive and negative electrodes to prevent short circuits. Since the top cover 2 needs to be in contact with the battery casing to ensure stability, the first insulating member 5 is required between the top cover 2 and the battery casing for insulation.

[0038] For example, as shown in Figure 1, the first insulating member 5 is provided with a first positioning post 51, and the top cover 2 is provided with a first positioning hole, into which the first positioning post 51 is inserted. The first positioning post 51 cooperates with the first positioning hole to prevent misalignment during assembly of the first insulating member 5 with the top cover 2, which could cause a short circuit due to partial contact between the top cover 2 and the battery casing, thereby improving battery safety. For example, two first positioning posts 51 and two first positioning holes are provided to enhance positioning accuracy.

[0039] In other embodiments, the top cover 2 is provided with a first positioning column 51 , and the first insulating member 5 is provided with a first positioning hole, which can also achieve the positioning effect between the top cover 2 and the first insulating member 5 .

[0040] After battery packs are assembled, busbars must be welded to connect the electrodes of multiple batteries in series or parallel, enabling access to external circuits. However, the battery terminals 3 are small, resulting in weak weld strength. To address this issue, as shown in Figures 1 and 2, the battery cover also includes terminals 7, which are fixedly attached to the top cover 2 and electrically connected to the ends of the terminals 3 extending beyond the top cover 2. Terminals 7 can be made of a suitable material based on welding performance, and a sufficiently large welding area can be designed to meet welding requirements, thereby improving weld strength to the busbars.

[0041] Exemplarily, the battery cover also includes a second insulating member 8, which is disposed between the terminal 7 and the top cover 2. The second insulating member 8 is configured to insulate the top cover 2 from the terminal 3, and cooperates with the first insulating member 5 to insulate the top cover 2 from the positive and negative electrodes of the battery, respectively, further improving the safety of the battery and reducing the risk of short circuits.

[0042] Illustratively, the second insulating member 8 is provided with a second positioning post 81, and the terminal 7 is provided with a second positioning hole, into which the second positioning post 81 is inserted. The second positioning post 81 cooperates with the second positioning hole to prevent misalignment during assembly of the second insulating member 8 with the terminal 7, which could cause partial contact between the terminal 7 and the top cover 2, thereby improving battery safety. Illustratively, two second positioning posts 81 and two second positioning holes are provided to enhance positioning accuracy.

[0043] In other embodiments, the terminal 7 is provided with a second positioning column 81 , and the second insulating member 8 is provided with a second positioning hole, which can also achieve the positioning effect between the terminal 7 and the second insulating member 8 .

[0044] For example, the interior of the battery case is filled with electrolyte, and the seal between the terminal 3 and the top cover 2, or between the terminal 3 and the first insulating member 5, is poor. As shown in Figures 1 and 2, to prevent electrolyte leakage, the battery cover also includes a sealing ring 6, which is sleeved on the terminal 3 and sandwiched between the first insulating member 5 and the top cover 2. The sealing ring 6 ensures the seal between the sealing ring 6 and the terminal 3 through its own elasticity. The top cover 2 sandwiches the sealing ring 6 on the first insulating member 5, which can ensure the seal between the sealing ring 6 and the first insulating member 5, thereby preventing electrolyte leakage.

[0045] To improve battery safety and prevent explosion or deflagration due to overcharging or impact, the battery cover also includes an explosion-proof valve 1, which is disposed on the top cover 2. For example, the top cover 2 is provided with a stepped hole, which includes a large-diameter section and a small-diameter section. The explosion-proof valve 1 is disposed at the end of the top cover 2 provided with the large-diameter section and abuts against the step between the large-diameter section and the small-diameter section.

[0046] As shown in Figures 3 and 4, the explosion-proof valve 1 is provided with an annular groove 12, which divides the explosion-proof valve 1 into a rupture portion 13 and a fixed portion 14. An arc-shaped pressure-bearing groove 15 is recessed on one side of the rupture portion 13, and the bottom of the pressure-bearing groove 15 is located in the annular groove 12. The fixed portion 14 is configured to be welded or glued to the inner wall of the stepped hole to fix the explosion-proof valve 1.

[0047] The explosion-proof valve 1 is provided with an annular groove 12 to reduce its own strength. Due to the smaller thickness of the annular groove 12, the explosion-proof valve 1 is more likely to rupture at the annular groove 12 and release pressure when subjected to gas impact. At the same time, the pressure-bearing groove 15 of the rupture portion 13 faces the interior of the battery. When the gas inside the battery impacts the explosion-proof valve 1, more gas is gathered at the pressure-bearing groove 15, and the curved surface of the pressure-bearing groove 15 has a larger area than the flat surface, so the gas pressure at the pressure-bearing groove 15 is greater and more concentrated, causing the rupture portion 13 to be subjected to greater pressure than the fixed portion 14, further causing the explosion-proof valve 1 to rupture preferentially from the annular groove 12.

[0048] The explosion-proof valve 1 can rupture at the annular groove 12 when subjected to gas pressure, and the rupture position is controllable, thereby improving safety.

[0049] For example, the explosion-proof valve 1 is provided with a liquid injection hole 11, so that the explosion-proof valve 1 also integrates the function of the liquid injection hole 11. During the production process, the explosion-proof valve 1 and the liquid injection hole 11 are processed and produced in an integrated manner, which can not only improve production efficiency but also reduce manufacturing costs. Moreover, since the explosion-proof valve 1 is integrated with the liquid injection hole 11, the space required for the liquid injection hole 11 on the battery cover is greatly reduced, thereby increasing the installation space of the explosion-proof valve 1, effectively improving the pressure control capability of the explosion-proof disk, and thus effectively improving the safety of the lithium battery.

[0050] For example, as shown in Figures 3 and 4, the explosion-proof valve 1 is provided with a blocking groove 16, and the injection hole 11 is provided at the bottom of the blocking groove 16. After the electrolyte is injected into the battery through the injection hole 11, the operator needs to block the injection hole 11 to prevent leakage of the electrolyte. Generally, the injection hole 11 is blocked by a colloid, and the blocking groove 16 can provide space for the colloid that blocks the injection hole 11, which can not only increase the contact area between the colloid and the explosion-proof valve 1 and improve the blocking effect, but also prevent the colloid from bulging, thereby ensuring the flatness of the surface of the top cover 2.

[0051] For example, the blocking groove 16 needs to avoid the position of the annular groove 12, that is, the blocking groove 16 can only be set inside the rupture portion 13 or the fixing portion 14. If the blocking groove 16 is set on the fixing portion 14, the local strength of the fixing portion 14 is relatively weak, which easily makes the rupture position of the explosion-proof valve 1 uncontrollable when it ruptures. Therefore, the blocking groove 16 is set inside the annular groove 12. For example, the blocking groove 16 is located at the center of the annular groove 12 so that the rupture portion 13 can be evenly ruptured along the annular groove 12 when a force is applied.

[0052] For example, the bottom of the annular groove 12 is provided with a notch 121. By providing the notch 121 at the bottom of the annular groove 12, the strength of the annular groove 12 can be further reduced, and the specific size and number of the notch 121 can be controlled according to the design requirements of the explosion-proof valve 1, so that when the internal pressure of the battery reaches a preset value, the explosion-proof valve 1 can be ruptured from the annular groove 12.

[0053] For example, the width of the notch 121 gradually decreases from the notch opening to the bottom of the annular groove 12. The bottom of the notch 121 is sharp, and the stress concentration is strong, which can further reduce the strength of the notch 121.

[0054] Exemplarily, the notches 121 extend along the circumference of the annular groove 12 so that the strength of each part of the annular groove 12 is equal and the annular groove 12 can crack evenly when subjected to stress.

[0055] For example, the explosion-proof valve 1 is made of metal. Metal's ductility facilitates integral stamping, improving production efficiency and reducing costs. Furthermore, metal has excellent weldability, allowing the explosion-proof valve 1 to be secured to the top cover 2 by welding, resulting in a simple process and high production efficiency.

[0056] Exemplarily, the explosion-proof valve 1 and the top cover 2 are made of the same metal to improve welding stability, such as aluminum, steel, etc.

Claims

1. An explosion-proof valve, wherein the explosion-proof valve (1) is provided with an annular groove (12), wherein the annular groove (12) divides the explosion-proof valve (1) into a rupture portion (13) and a fixed portion (14), and an arc-shaped pressure-bearing groove (15) is concavely provided on one side of the rupture portion (13), and the bottom of the pressure-bearing groove (15) is located within the annular groove (12).

2. The explosion-proof valve according to claim 1, wherein: The explosion-proof valve (1) is provided with a liquid injection hole (11).

3. The explosion-proof valve according to claim 2, wherein: The explosion-proof valve (1) is provided with a blocking groove (16), and the injection hole (11) is provided at the bottom of the blocking groove (16).

4. The explosion-proof valve according to claim 1, wherein: The bottom of the annular groove (12) is provided with a notch (121).

5. The explosion-proof valve according to claim 4, wherein: The width of the notch (121) gradually decreases in the direction from the notch opening to the bottom of the annular groove (12).

6. The explosion-proof valve according to claim 4, wherein: The notch (121) extends along the circumference of the annular groove (12).

7. The explosion-proof valve according to claim 1, wherein: The explosion-proof valve (1) is made of metal material.

8. A battery cover, comprising the explosion-proof valve according to any one of claims 1 to 7, and further comprising a top cover (2), wherein the explosion-proof valve (1) is arranged on the top cover (2).

9. The battery cover according to claim 8, further comprising a first insulating member (5), wherein the first insulating member (5) is detachably connected to the top cover (2) and is located between the top cover (2) and the battery housing.

10. The battery cover according to claim 9, wherein: One of the first insulating member (5) and the top cover (2) is provided with a first positioning column (51), and the other is provided with a first positioning hole, and the first positioning column (51) is inserted into the first positioning hole.

11. A battery comprising the battery cover according to any one of claims 8 to 10, and a battery casing, wherein the battery casing is provided with a mounting hole, and the battery cover is buckled into the battery casing to close the mounting hole.