Explosion-proof structure, cover plate and battery

Abstract

The invention relates to the technical field of batteries, and provides an explosion-proof structure, a cover plate and a battery, the explosion-proof structure comprises an explosion-proof main body, the explosion-proof main body comprises an inner side and an outer side, the inner side of the explosion-proof main body is provided with at least two weak structures, and in the weak structures, the outer side of the explosion-proof main body is provided with an opening; the thickness of at least one weak structure from the inner side to the outer side is larger than the thickness of the other weak structure from the inner side to the outer side. And the acting force of the high-temperature gas acting on the explosion-proof structure before the explosion-proof structure bursts can be known.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an explosion-proof structure, a cover plate and a battery. Background Art

[0002] Lithium-ion batteries are widely used in new energy, consumer electronics, wearable electronic devices and other fields due to their advantages such as high energy density, long cycle life and high safety.

[0003] To ensure the safe use of lithium-ion batteries, lithium-ion batteries are usually equipped with explosion-proof structures, which can burst when the temperature inside the lithium-ion battery is too high, so that the high-temperature gas inside the lithium-ion battery can be discharged from the explosion-proof structure, thereby completing the pressure relief. At present, the explosion-proof structure usually adopts an irreversible one-time structure, that is, after the high-temperature gas acts on the explosion-proof structure and causes the explosion-proof structure to burst, the structural characteristics of the explosion-proof structure are damaged, and it is impossible to judge the force of the high-temperature gas acting on the explosion-proof structure before the explosion based on the damaged explosion-proof structure. Summary of the invention

[0004] The present application provides an explosion-proof structure, a cover plate and a battery, which can be used to obtain the force exerted by high-temperature gas on the explosion-proof structure before the explosion of the explosion-proof structure.

[0005] The first aspect of the present application provides a method comprising:

[0006] An explosion-proof body, the explosion-proof body comprising an inner side and an outer side, the explosion-proof body being provided with at least two weak structures on its inner side, wherein the thickness of at least one of the weak structures from the inner side to the outer side is greater than the thickness of another of the weak structures from the inner side to the outer side.

[0007] According to the explosion-proof structure described in the first aspect of the present application, by designing at least two weak structures with different thicknesses, when one of the weak structures bursts, due to the difference in thickness, the other weak structure only deforms but does not burst, thereby making the other weak structure still in a complete form, and the force acting on the explosion-proof structure by the high-temperature gas before the explosion can be inferred by measuring the deformation amount of the weak structure, and by comparing the force with the set pressure relief value, it can be known whether the battery is normally relieved, and the actual working condition of the battery when the pressure relief occurs can be accurately judged, which can provide guidance for battery repair, redesign, etc.

[0008] In a possible implementation, the weak structure includes a first weak structure and a second weak structure, and in a direction from the inside to the outside, a thickness of the first weak structure is smaller than a thickness of the second weak structure.

[0009] In a possible implementation manner, the first weak structure includes an edge structure arranged at an edge of the explosion-proof body.

[0010] In one possible implementation, the edge structure is ring-shaped.

[0011] In one possible implementation, the explosion-proof body includes two arc segments arranged opposite to each other and a straight segment connected between the arc segments, and the edge structure includes an arc edge portion arranged corresponding to the arc segments and a straight edge portion arranged corresponding to the straight segments.

[0012] In a possible implementation, the first weak structure further includes an inner structure disposed inside the explosion-proof body, and the inner structure is connected to the edge structure.

[0013] In one possible implementation, the inner structure includes a first arc-shaped structure and a second arc-shaped structure, the first arc-shaped structure is formed with two first connecting ends, the second arc-shaped structure is formed with two second connecting ends, and the two first connecting ends and the two second connecting ends are connected to the edge structure.

[0014] In a possible implementation manner, the two first connection ends are arranged opposite to the two second connection ends.

[0015] In a possible implementation manner, the first arc-shaped structure and the second arc-shaped structure intersect at the center of the explosion-proof body.

[0016] In a possible implementation manner, the second weak structure is disposed close to the first weak structure.

[0017] In a possible implementation manner, a pit is formed on the inner side of the explosion-proof body, and the pit forms the first weak structure and / or the second weak structure.

[0018] A second aspect of the present application provides a cover plate, comprising the explosion-proof structure described in the first aspect.

[0019] A third aspect of the present application provides a battery, comprising the cover plate described in the second aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art description are briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0021] Figure 1A bottom view of an explosion-proof structure provided according to an embodiment of the present application is shown;

[0022] Figure 2 A side view of an explosion-proof structure provided according to an embodiment of the present application is shown.

[0023] Reference numerals:

[0024] 100-first weak structure; 110-edge structure; 120-inner structure; 111-arc edge portion; 112-straight edge portion; 121-first arc structure; 122-second arc structure; 121a-first connection end; 122a-second connection end;

[0025] 200-Second weakest structure;

[0026] 10-explosion-proof body; 11-inner side; 12-outer side; 13-arc section; 14-straight section;

[0027] 20-Weak structure. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] In recent years, with the rapid development of new energy technologies, lithium-ion batteries are also in a stage of rapid development. Lithium-ion batteries are constantly being optimized and innovated in terms of material selection, process manufacturing, structural design, etc. When designing lithium-ion batteries, they mainly face problems such as capacity, safety, and lifespan that need to be overcome. With the continuous exploration of materials, processes, and structures, lithium-ion batteries have also been continuously improved in terms of performance, which is mainly reflected in the advantages of lithium-ion batteries such as high energy density, long cycle life, and high safety. Therefore, lithium-ion batteries are often used in new energy fields, consumer electronics fields, wearable electronic devices, and many other fields.

[0030] Lithium-ion batteries usually include a shell, a core and a cover. The shell is usually made of metal materials, such as aluminum or steel, to improve the structural stability of lithium-ion batteries and their performance in terms of pressure resistance and impact resistance. The core is the core component of lithium-ion batteries. The core can store or release electrical energy. The core usually includes structures such as a positive electrode sheet, a negative electrode sheet and a diaphragm. The positive electrode sheet is provided with a positive electrode active material containing lithium, and the negative electrode sheet is provided with a negative electrode active material that can interact with lithium ions. Lithium-ion batteries are based on the interaction between lithium ions between the positive electrode sheet and the negative electrode sheet to achieve the purpose of charging and discharging, thereby achieving the storage and release of electrical energy. The cover is connected to the end of the shell. Its main function is to enclose the core in the shell, and it also needs to form an electrical connection with the core. Based on this, a pole column is usually designed on the cover, which can be connected to the pole ear on the core. The pole column can be exposed from the cover to form the positive or negative pole of the lithium-ion battery. In order to ensure the safe use of lithium-ion batteries and prevent safety accidents such as explosions, lithium-ion batteries are usually equipped with an explosion-proof structure on the cover. The explosion-proof structure can burst when the internal temperature of the lithium-ion battery is too high, thereby completing the pressure relief.

[0031] At present, explosion-proof structures usually adopt irreversible disposable structures. For example, a weak structure can be formed by carving notches on the explosion-proof structure. When the pressure value inside the lithium-ion battery reaches a level that can break through the weak structure, the explosion-proof structure can burst at the weak structure and complete the pressure relief. There is an obvious defect in using the above-mentioned weak structure, that is, when the weak structure is destroyed, the structural characteristics of the explosion-proof structure are damaged. This damage cannot be repaired, and there is no regularity to be found in this damage. It is impossible to explore the stress conditions on the inside or outside of the explosion-proof structure, resulting in the inability to judge the force of the high-temperature gas on the explosion-proof structure before the explosion based on the damaged explosion-proof structure. It is also impossible to judge whether the pressure value inside the lithium-ion battery is within the design range of the pressure relief value when the explosion-proof structure bursts. Therefore, it is difficult to infer the actual working condition of the lithium-ion battery based on the explosion of the explosion-proof structure.

[0032] Based on the above-mentioned status quo and problems, an embodiment of the present application provides an explosion-proof structure, which is configured with at least two weak structures, one of which is used for pressure relief and will burst under pressure, and the other is used as a comparison benchmark and will deform but not burst under pressure. The two weak structures are arranged on the side of the explosion-proof structure facing the pole core. When one of the weak structures bursts and releases pressure, the internal high-temperature gas of the lithium-ion battery can act on the other weak structure at the same time. The deformation amount of the weak structure can be used to infer the force exerted by the high-temperature gas on the explosion-proof structure before the explosion.

[0033] According to the above-mentioned explosion-proof structure, the embodiment of the present application also provides a cover plate and a battery. Based on the explosion-proof structure, the actual working condition of the battery when pressure relief occurs can be accurately judged, and guidance can be provided for battery repair, redesign, etc.

[0034] Figure 1 A bottom view of an explosion-proof structure provided according to an embodiment of the present application is shown; Figure 2 A side view of an explosion-proof structure provided according to an embodiment of the present application is shown.

[0035] In the examples of this application, please refer to Figure 1 and Figure 2 The explosion-proof structure includes an explosion-proof body 10, which includes an inner side 11 and an outer side 12. The explosion-proof body 10 is provided with at least two weak structures 20 on its inner side 11. Among these weak structures 20, the thickness of at least one weak structure 20 from the inner side 11 to the outer side 12 is greater than the thickness of another weak structure 20 from the inner side 11 to the outer side 12.

[0036] It should be noted that the inner side 11 refers to the side of the explosion-proof structure facing the pole core in the battery, that is, the high-temperature gas inside the battery can act on the inner side 11, and the outer side 12 refers to the side of the explosion-proof structure facing outward. By providing at least two weak structures 20 on the inner side 11 of the explosion-proof body 10, the high-temperature gas can act on at least two weak structures 20 at the same time.

[0037] It can be understood that the explosion-proof body 10 can be made of uniform material. When the thickness of one weak structure 20 is greater than the thickness of the other weak structure 20, as the temperature inside the battery continues to rise, the force of the high-temperature gas on the two weak structures 20 also increases. When one of the weak structures 20 bursts, the other weak structure 20 is squeezed by the force but has not yet burst. Therefore, the force acting on the weak structure 20 when the burst occurs can be inferred by checking the deformation of the other weak structure 20.

[0038] The explosion-proof structure in the embodiment of the present application is designed with at least two weak structures 20 of different thicknesses. When one of the weak structures 20 bursts, due to the difference in thickness, the other weak structure 20 only deforms but does not burst, thereby making the other weak structure 20 still in a complete form. The deformation amount of the weak structure 20 can be measured to infer the force exerted by the high-temperature gas on the explosion-proof structure before the explosion. By comparing the force with the set pressure relief value, it can be determined whether the battery is normally depressurized, and the actual working condition of the battery when the pressure relief occurs can be accurately judged, which can provide guidance for battery repair, redesign, etc.

[0039] It can be understood that by comparing the applied force with the pressure relief value, the following conclusion can be drawn: when the applied force is greater than the pressure relief value, it can be judged that the battery belongs to the normal pressure relief category; when the applied force is less than the pressure relief value, it can be judged that the battery belongs to the abnormal pressure relief category. Therefore, it can be judged that the internal structure of the battery is still in normal operation. Based on this, attention can be paid to other possible causes of explosion-proof structure bursting, which is convenient for providing direction for battery improvement.

[0040] In the embodiment of the present application, combined with the above, it can be known that the thickness of the weak structure 20 and the design range of the pressure relief value can be associated, and this association can be used as a design standard for designing the weak structure 20. For example, the thickness of the weak structure 20 can usually be designed to be 0.1 mm, and an error of 0.05 mm is allowed. The thinner one of the weak structures can be designed according to this size, and the thicker one of the weak structures can be thickened in this size, for example, its thickness is designed to be 0.15 mm, and an error of 0.05 mm is allowed.

[0041] In the embodiment of the present application, the design of at least two weak structures 20 with different thicknesses can be used to infer the force of the high-temperature gas on the explosion-proof structure before the explosion occurs. In order to improve the accuracy of the body side results, the forces acting on the two weak structures 20 should be as similar as possible at the same time. For this reason, the embodiment of the present application also designs the shape and arrangement of the weak structures 20 to make the forces as evenly distributed as possible on the inner side 11 of the explosion-proof body 10. In these structural designs, a symmetrical structure can be adopted. In addition, the number of weak structures 20 can also be set according to actual needs. For ease of understanding and simplified description, the following embodiments of the present application will mainly be described by taking two weak structures 20 as an example.

[0042] In some embodiments, please refer to Figure 2 The weak structure 20 includes a first weak structure 100 and a second weak structure 200 . In the direction from the inner side 11 to the outer side 12 , the thickness of the first weak structure 100 is smaller than the thickness of the second weak structure 200 .

[0043] Here, the structural composition of the explosion-proof structure can be simplified by designing the first weak structure 100 and the second weak structure 200.

[0044] It is understandable that the first weak structure 100 is used as burst pressure relief, and the second weak structure 200 is used as a comparison reference. To enhance the synergistic effect of the two, the first weak structure 100 and the second weak structure 200 can be designed to be as close as possible to the inner side 11 of the explosion-proof body 10.

[0045] For example, in order to perform its bursting pressure relief function, the first weak structure 100 can be evenly distributed over the entire inner side 11 of the explosion-proof body 10. At this time, the first weak structure 100 can be arranged at the edge position of the inner side 11 and at the center position of the inner side 11. The first weak structure 100 can divide the inner side 11 of the explosion-proof body 10 into several areas. The second weak structure 200 can be set in any area and made close to the first weak structure 100. The second weak structure 200 can be at the edge position of the inner side 11 or at the center position of the inner side 11.

[0046] In some embodiments, please refer to Figure 1 The first weak structure 100 includes an edge structure 110 disposed at the edge of the explosion-proof body 10 .

[0047] The edge structure 110 is located at the edge of the explosion-proof body 10 to improve the structural stability of the explosion-proof body 10 at the edge.

[0048] In some embodiments, please refer to Figure 1 The edge structure 110 may be annular, and the edge structure 110 surrounds the explosion-proof body 10 in the circumferential direction. The edge structure 110 may be a continuous and uninterrupted structure, thereby further improving the structural stability of the explosion-proof body 10 at the edge.

[0049] By providing the edge structure 110 at the edge, the sensing sensitivity of the first weak structure 100 to the internal pressure of the battery can be improved, thereby ensuring the normal pressure relief action of the battery.

[0050] It is understandable that the number of the edge structures 110 is not limited. Figure 1 In the example shown, the edge structure 110 is a circle. In other embodiments, the edge structure 110 may also be formed into a multi-circle structure at the edge of the explosion-proof body 10 .

[0051] When a multi-circle structure is used, two adjacent circle structures can be connected by a connecting bridge or the like, thereby improving the integrity of the edge structure 110 .

[0052] In some specific embodiments, please refer to Figure 1 The explosion-proof body 10 includes two arc segments 13 arranged opposite to each other and a straight segment 14 connected between the arc segments 13 , and the edge structure 110 includes an arc edge portion 111 arranged corresponding to the arc segment 13 and a straight edge portion 112 arranged corresponding to the straight segment 14 .

[0053] In the above example, the edge structure 110 is adapted to the shape of the explosion-proof body 10 , wherein the arc edge portion 111 corresponds to the arc segment 13 , and the straight edge portion 112 corresponds to the straight segment 14 , thereby enhancing the overall stability of the explosion-proof valve structure.

[0054] The above-mentioned embodiment can improve the structural stability of the first weak structure 100 at the edge through the design of the edge structure 110. It can be understood that the specific structure of the edge structure 110 is not limited. For example, the edge structure 110 in the above-mentioned embodiment is annular, and the annular shape can be a smooth linear structure or a curved linear structure such as a wavy shape.

[0055] On the basis of the above-mentioned embodiment, the structural stability of the first weak structure 100 on its inner side 11 may also be improved through structural design.

[0056] For example, in some embodiments, see Figure 1 The first weak structure 100 further includes an inner side 11 structure 120 disposed inside the explosion-proof body 10 , and the inner side 11 structure 120 is connected to the edge structure 110 .

[0057] The inner side 11 structure 120 can improve the structural stability of the explosion-proof body 10 at the inside, and by connecting the inner side 11 structure 120 with the edge structure 110 , the overall structural stability of the explosion-proof body 10 can be improved at the same time.

[0058] In some embodiments, please refer to Figure 1 The inner side structure 120 includes a first arc structure 121 and a second arc structure 122 . The first arc structure 121 has two first connection ends 121 a , and the second arc structure 122 has two second connection ends 122 a . The two first connection ends 121 a and the two second connection ends 122 a are connected to the edge structure 110 .

[0059] Here, through the connection between the first connection end 121a, the second connection end 122a and the edge structure 110, the structural strength distribution of the explosion-proof body 10 can be uniform, and its edge and interior can form a force transmission channel. When the high-temperature gas inside the battery acts on the inner side 11 of the explosion-proof body 10, the force formed by the high-temperature gas can be evenly distributed to the entire inner side 11 of the explosion-proof body 10.

[0060] It should be noted that the connection ends formed by the arc structure can be modified in various ways. The above-mentioned first arc structure 121 forms two first connection ends 121a, and the second arc structure 122 forms two second connection ends 122a for illustrative purposes only. In other embodiments, the first arc structure 121 can form more first connection ends 121a, and the second arc structure 122 can form more second connection ends 122a.

[0061] In addition, there is no limitation on the specific setting positions of the first arc structure 121 and the second arc structure 122. The first arc structure 121 can be designed in a manner of being deviated from each other or in a manner of being crossed with each other. To simplify the description and facilitate understanding, the following embodiments will be described in a manner in which the first arc structure 121 and the second arc structure 122 are designed in a manner of being deviated from each other.

[0062] In some embodiments, please refer to Figure 1 The two first connection ends 121a of the first arc-shaped structure 121 can be connected to the aforementioned straight edge portion 112. Specifically, the straight edge portion 112 and the arc edge portion 111 form two connection points, and the two first connection ends 121a can be connected to the two connection points. Similarly, the two second connection ends 122a of the second arc-shaped structure 122 can also be connected to the two connection points formed by the straight edge portion 112 and the arc edge portion 111.

[0063] It is understandable that, for the edge structure 110, the structural strength at the connection point between the straight edge portion 112 and the arc edge portion 111 is relatively low, and the overall stability of the first weak structure 100 can be improved by connecting the first connection end 121a and the second connection end 122a to the connection point.

[0064] In some embodiments, the two first connection ends 121 a and the two second connection ends 122 a are disposed opposite to each other.

[0065] In some embodiments, the first arc structure 121 and the second arc structure 122 intersect at the center of the explosion-proof body 10 , thereby improving the structural stability of the inner structure 120 .

[0066] In some embodiments, please refer to Figure 1 The second weak structure 200 is designed to be strip-shaped. The second weak structure 200 can be arranged on one side of the first weak structure 100 , for example, can be arranged on one side of the aforementioned straight edge portion 112 .

[0067] Here, by using the strip-shaped second weak structure 200 , it is convenient to form a contrast between the second weak structure 200 and the first weak structure 100 , which is beneficial to improve the accuracy of the inferred pressure value.

[0068] Of course, in other embodiments, the second weak structure 200 may also be in other shapes, such as an arc shape, a wave shape, etc.

[0069] In addition, the number of the second weak structures 200 can be varied, and can be 2, 3, etc. When two are used, they can be located on one side of the two straight edge portions 112 respectively, so that the accuracy of the inferred pressure value can be further improved through analysis and comparison.

[0070] In the embodiment of the present application, a pit is formed on the inner side 11 of the explosion-proof body 10 , and the pit forms the first weak structure 100 and / or the second weak structure 200 .

[0071] The pit can be formed by removing material, for example, the explosion-proof body 10 with uniform thickness can be manufactured first, and then the first weak structure 100 and the second weak structure 200 are processed on the inner side 11 of the explosion-proof body 10. The pit can also be manufactured by injection molding.

[0072] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0073] In the description of the present application, it should be understood that the terms "including" and "having" and any variations thereof used in the embodiments of the application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to these processes, methods, products or apparatuses.

[0074] Unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense, for example, it can be a fixed connection, it can also be a detachable connection, or it can be integrated; it can be directly connected, or it can be indirectly connected through an intermediate medium, it can make the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances. In addition, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An explosion-proof structure, characterized in that: include: An explosion-proof body, the explosion-proof body comprising an inner side and an outer side, the explosion-proof body being provided with at least two weak structures on its inner side, wherein the thickness of at least one of the weak structures from the inner side to the outer side is greater than the thickness of another of the weak structures from the inner side to the outer side.

2. The explosion-proof structure according to claim 1, characterized in that: The weak structure includes a first weak structure and a second weak structure, and in a direction from the inner side to the outer side, the thickness of the first weak structure is smaller than the thickness of the second weak structure.

3. The explosion-proof structure according to claim 2, characterized in that: The first weak structure includes an edge structure arranged at an edge of the explosion-proof body.

4. The explosion-proof structure according to claim 3, characterized in that: The edge structure is ring-shaped.

5. The explosion-proof structure according to claim 4, characterized in that: The explosion-proof body includes two arc segments arranged opposite to each other and a straight segment connected between the arc segments, and the edge structure includes an arc edge portion arranged corresponding to the arc segments and a straight edge portion arranged corresponding to the straight segment.

6. The explosion-proof structure according to claim 3, characterized in that: The first weak structure further includes an inner structure disposed inside the explosion-proof body, and the inner structure is connected to the edge structure.

7. The explosion-proof structure according to claim 6, characterized in that: The inner structure includes a first arc-shaped structure and a second arc-shaped structure, the first arc-shaped structure is formed with two first connecting ends, the second arc-shaped structure is formed with two second connecting ends, and the two first connecting ends and the two second connecting ends are connected to the edge structure.

8. The explosion-proof structure according to claim 7, characterized in that: The two first connection ends are arranged opposite to the two second connection ends.

9. The explosion-proof structure according to claim 7, characterized in that: The first arc-shaped structure and the second arc-shaped structure intersect at the center of the explosion-proof body.

10. The explosion-proof structure according to any one of claims 2 to 9, characterized in that: The second weak structure is arranged close to the first weak structure.

11. The explosion-proof structure according to any one of claims 2 to 9, characterized in that: A pit is formed inside the explosion-proof body, and the pit forms the first weak structure and / or the second weak structure.

12. A cover plate, characterized in that: The explosion-proof structure comprises the explosion-proof structure according to any one of claims 1 to 11.

13. A battery, characterized in that: Comprising the cover plate as claimed in claim 12.

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