Anti-explosion valve protection sheet and battery cover plate

Abstract

The invention belongs to the technical field of batteries, and discloses an explosion-proof valve protection sheet and a battery cover plate, the explosion-proof valve protection sheet comprises an inner layer patch and an outer layer patch, the inner layer patch comprises a first protection base body and a first adhesive layer, the first adhesive layer is continuously arranged around the circumferential edge of the first protection base body, and the outer layer patch comprises a second protection base body and a second adhesive layer; the outer-layer patch comprises a second protective base body and a second adhesive layer, and the second adhesive layer is continuously arranged around the circumferential edge of the second protective base body and used for bonding the second protective base body to the side, away from the anti-explosion valve, of the first protective base body. The protection performance is enhanced through double-layer protection of the first protection base body and the second protection base body, and meanwhile the situation that the first protection base body and the second protection base body are too thick, and the difficulty that pressure gas breaks through the anti-explosion valve protection piece during thermal runaway is increased is not needed; compared with a traditional single-layer anti-explosion valve protection plate, the anti-explosion valve protection plate has the characteristic of rapid exhaust and better protection performance.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to an explosion-proof valve protection sheet and a battery cover. Background Art

[0002] With the continuous development of battery technology, the safety performance of batteries has become a factor that needs to be considered when designing batteries. Explosion-proof valves are generally formed on a plain aluminum plate by integrated stamping or welding. When the battery cell produces excessive gas and the accumulated air pressure inside the battery cell exceeds the design value, the explosion-proof valve can burst and release the pressure in time, thus playing a role in pressure relief protection. An explosion-proof valve protection sheet is usually attached to the outside of the explosion-proof valve. The explosion-proof valve protection sheet can prevent foreign objects from falling into the explosion-proof valve area and affecting the performance of the explosion-proof valve. At the same time, during the battery filling stage, the explosion-proof valve protection sheet can also prevent the overflowed electrolyte from seeping into the explosion-proof valve.

[0003] However, at present, the explosion-proof valve protection sheet is usually single-layer. In order to ensure that the pressure gas that breaks through the explosion-proof valve can quickly break through the explosion-proof valve protection sheet when thermal runaway occurs, the explosion-proof valve protection sheet is usually thin. However, the thin explosion-proof valve protection sheet is prone to damage when protecting the explosion-proof valve, causing electrolyte or dust to erode the explosion-proof valve. Therefore, the traditional single-layer explosion-proof valve protection sheet cannot achieve both rapid exhaust and protection of the explosion-proof valve. Summary of the invention

[0004] The purpose of the present invention is to provide an explosion-proof valve protection sheet and a battery cover plate, which have good protection effect and fast exhaust speed.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In one aspect, an explosion-proof valve protection sheet is provided, the explosion-proof valve protection sheet comprising:

[0007] An inner layer patch, the inner layer patch comprising a first protective matrix and a first adhesive layer, the first adhesive layer being continuously arranged around a circumferential edge of the first protective matrix and being used to fix the first protective matrix;

[0008] The outer layer patch includes a second protective matrix and a second adhesive layer, wherein the second adhesive layer is continuously arranged around the circumferential edge of the second protective matrix and is used to bond the second protective matrix to the side of the first protective matrix away from the explosion-proof valve.

[0009] Optionally, a plurality of first exhaust structures arranged at intervals are provided on the first protective substrate.

[0010] Optionally, a plurality of second exhaust structures arranged at intervals are provided on the second protective substrate, and the plurality of second exhaust structures are arranged alternately with the plurality of first exhaust structures.

[0011] Optionally, both the first exhaust structure and the second exhaust structure are through-hole structures, and the cross-section of the through-hole structure is circular, elliptical or polygonal.

[0012] Optionally, the thickness dimension of the first protective matrix in the first direction is t1, and 0.05 mm ≤ t1 ≤ 0.3 mm is satisfied;

[0013] And / or, the thickness dimension of the second protective matrix in the first direction is t2, and 0.05 mm ≤ t2 ≤ 0.3 mm is satisfied.

[0014] Optionally, the thickness dimension of the first adhesive layer in the first direction is t3, and 0.05 mm ≤ t3 ≤ 0.15 mm is satisfied;

[0015] And / or, the thickness dimension of the second adhesive layer in the first direction is t4, and 0.05 mm ≤ t4 ≤ 0.15 mm is satisfied.

[0016] Optionally, a first color coating is applied outside the first protective matrix, a second color coating is applied outside the second protective matrix, and the colors of the first color coating and the second color coating are different.

[0017] Optionally, the first protective matrix and the second protective matrix are prepared from PET, PC, PP, PVC or PE materials.

[0018] Optionally, the first adhesive layer and the second adhesive layer are prepared from pressure-sensitive adhesive or heat-sensitive adhesive.

[0019] On the other hand, a battery cover plate is further provided. The battery cover plate includes a cover plate body, an explosion-proof valve and an explosion-proof valve protection piece as described in any one of the above. An installation hole is formed in the cover plate body, the explosion-proof valve is arranged in the installation hole, and the explosion-proof valve protection piece is connected to the cover plate body and is used to seal the installation hole.

[0020] Advantages of the present invention:

[0021] The present invention provides an explosion-proof valve protection piece. By providing an inner patch composed of a first protective matrix and a first adhesive layer and an outer patch composed of a second protective matrix and a second adhesive layer, the explosion-proof valve protection piece can not only enhance the protection performance by the double protection of the first protective matrix and the second protective matrix, but also does not need to make the thickness of the first protective matrix and the second protective matrix too thick, increasing the difficulty for the pressure gas to break through the explosion-proof valve protection piece during thermal runaway. Compared with the traditional single-layer explosion-proof valve protection piece, the explosion-proof valve protection piece has both the characteristics of rapid exhaust and better protection performance.

[0022] The present invention also provides a battery cover plate. By applying the above-mentioned explosion-proof valve protection sheet, the explosion-proof valve is protected from external dust and electrolyte erosion, improving the product quality. At the same time, rapid exhaust during thermal runaway is ensured, enhancing the product safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the front view of the explosion-proof valve protection sheet provided by the present invention;

[0024] Figure 2 is the back view of the explosion-proof valve protection sheet provided by the present invention;

[0025] Figure 3 is the structural sectional view of the explosion-proof valve protection sheet provided by the present invention;

[0026] Figure 4 is Figure 3 the enlarged structural view of part A in

[0027] Figure 5 is the schematic diagram of the explosion-proof valve protection sheet provided by the present invention applied to a square shell battery.

[0028] In the figure:

[0029] 100, cover plate body;

[0030] 1, inner patch; 11, first protective matrix; 12, first adhesive layer; 13, first exhaust structure;

[0031] 2, outer patch; 21, second protective matrix; 22, second adhesive layer; 23, second exhaust structure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the convenience of description, only parts related to the present invention are shown in the drawings, rather than all the structures.

[0033] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0035] In the description of this embodiment, the terms "upper", "lower", "right", etc., directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0036] If the traditional single-sided explosion-proof valve protection plate is used to achieve rapid exhaust, the thickness of the explosion-proof valve protection plate will be too thin, resulting in poor protection. If a higher level of protection is used, the exhaust resistance during thermal runaway will increase, and the rapid exhaust function cannot be achieved.

[0037] Therefore, in order to achieve both rapid exhaust and protection of the explosion-proof valve, this embodiment provides an explosion-proof valve protection sheet.

[0038] like Figures 1 to 5 As shown, the explosion-proof valve protection sheet includes an inner patch 1 and an outer patch 2. The inner patch 1 includes a first protective substrate 11 and a first adhesive layer 12. The first adhesive layer 12 is continuously arranged around the circumferential edge of the first protective substrate 11 and is used to fix the first protective substrate 11. The outer patch 2 includes a second protective substrate 21 and a second adhesive layer 22. The second adhesive layer 22 is continuously arranged around the circumferential edge of the second protective substrate 21 and is used to bond the second protective substrate 21 to the side of the first protective substrate 11 away from the explosion-proof valve.

[0039] The explosion-proof valve protection sheet is provided with an inner patch 1 composed of a first protective matrix 11 and a first adhesive layer 12, and an outer patch 2 composed of a second protective matrix 21 and a second adhesive layer 22. This can not only utilize the double-layer protection of the first protective matrix 11 and the second protective matrix 21 to enhance the protection, but also does not need to make the thickness of the first protective matrix 11 and the second protective matrix 21 too thick, thereby increasing the difficulty of the pressurized gas breaking through the explosion-proof valve protection sheet during thermal runaway. Compared with the traditional single-layer explosion-proof valve protection sheet, the explosion-proof valve protection sheet has both the characteristics of rapid exhaust and better protection.

[0040] In this embodiment, the first protective matrix 11 and the second protective matrix 21 are prepared from PET, PC, PP, PVC or PE materials, and the first adhesive layer 12 and the second adhesive layer 22 are prepared from pressure-sensitive adhesives or heat-sensitive adhesives.

[0041] The explosion-proof valve protection sheet can be used on different types of batteries, such as blade batteries, square shell batteries or large cylindrical batteries, etc. The position where the explosion-proof valve protection sheet is attached is determined by the position where the explosion-proof valve is set. If the explosion-proof valve is set on the battery cover plate, the explosion-proof valve protection sheet is also set on the battery cover plate. If the explosion-proof valve is set on the battery case, the explosion-proof valve protection sheet is also set on the battery case. In this embodiment, as Figure 5 shown, the explosion-proof valve protection sheet is set on the battery cover plate of the square shell battery.

[0042] Optionally, as Figure 2 shown, a plurality of first exhaust structures 13 are arranged at intervals on the first protective matrix 11. By arranging a plurality of first exhaust structures 13 at intervals on the first protective matrix 11, a channel is provided for the pressure gas to rush out of the first protective matrix 11 during thermal runaway. The number of the first exhaust structures 13 can be freely set according to requirements. In this embodiment, two first exhaust structures 13 are arranged at intervals on the first protective matrix 11.

[0043] Furthermore, as Figure 1 shown, a plurality of second exhaust structures 23 are arranged at intervals on the second protective matrix 21, and the plurality of second exhaust structures 23 are arranged staggered with the plurality of first exhaust structures 13. By arranging a plurality of second exhaust structures 23 at intervals on the second protective matrix 21, a channel is provided for the pressure gas to rush out of the second protective matrix 21 during thermal runaway, and the plurality of second exhaust structures 23 are arranged staggered with the plurality of first exhaust structures 13, so that even when external dust or electrolyte passes through the second exhaust structures 23 and passes through the second protective matrix 21, it will be blocked by the first protective matrix 11, thus realizing both the function of rapid exhaust and not affecting the protection of the explosion-proof valve.

[0044] The number of the second exhaust structures 23 can be freely set according to requirements. In this embodiment, one second exhaust structure 23 that is staggered with the two first exhaust structures 13 is arranged on the second protective matrix 21.

[0045] Even further, as Figures 1 to 4 shown, both the first exhaust structure 13 and the second exhaust structure 23 are through-hole structures, and the cross-section of the through-hole structure is circular or oval or polygonal.

[0046] Optionally, as Figure 3 、 Figure 4As shown, the thickness dimension t1 of the first protective substrate 11 in the first direction satisfies 0.05 mm ≤ t1 ≤ 0.3 mm. By defining the thickness dimension t1 of the first protective substrate 11 in the first direction, on the one hand, it avoids the excessive thickness of the first protective substrate 11, which leads to an increase in the difficulty of exhaust. On the other hand, it avoids the relatively thin thickness of the first protective substrate 11, which reduces the protective performance of the first protective substrate 11.

[0047] In this embodiment, the thickness dimension t1 of the first protective substrate 11 in the first direction can be any value between 0.05 mm and 0.3 mm or the range between any two values, such as 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc.

[0048] Optionally, as Figure 3 , Figure 4 shown, the thickness dimension t2 of the second protective substrate 21 in the first direction satisfies 0.05 mm ≤ t2 ≤ 0.3 mm. By defining the thickness dimension t2 of the second protective substrate 21 in the first direction, on the one hand, it avoids the excessive thickness of the second protective substrate 21, which leads to an increase in the difficulty of exhaust. On the other hand, it avoids the relatively thin thickness of the second protective substrate 21, which reduces the protective performance of the second protective substrate 21.

[0049] In this embodiment, the thickness dimension t2 of the second protective substrate 21 in the first direction can be any value between 0.05 mm and 0.3 mm or the range between any two values, such as 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc.

[0050] Optionally, as Figure 3 , Figure 4 shown, the thickness dimension t3 of the first adhesive layer 12 in the first direction satisfies 0.05 mm ≤ t3 ≤ 0.15 mm. By defining the thickness dimension t3 of the first adhesive layer 12 in the first direction, on the one hand, it avoids the too thin thickness of the first adhesive layer 12, which leads to a poor bonding strength to the first protective substrate 11 and causes the first protective substrate 11 to be easily detached. On the other hand, it avoids the too thick thickness of the first adhesive layer 12, which leads to adhesive overflow during bonding and causes the first adhesive layer 12 to overflow to other areas that do not need to be bonded.

[0051] In this embodiment, the thickness dimension t3 of the first adhesive layer 12 in the first direction can be any value between 0.05 mm and 0.15 mm or the range between any two values, such as 0.05 mm, 0.1 mm, 0.15 mm, etc.

[0052] Optionally, as Figure 3 , Figure 4As shown, the thickness dimension of the second adhesive layer 22 in the first direction is t4, and 0.05 mm ≤ t4 ≤ 0.15 mm is satisfied. By limiting the thickness dimension t4 of the second adhesive layer 22 in the first direction, on the one hand, it avoids the too thin thickness of the second adhesive layer 22, resulting in poor bonding strength to the second protective matrix 21 and causing the second protective matrix 21 to easily fall off. On the other hand, it avoids the too thick thickness of the second adhesive layer 22, resulting in glue overflow during bonding and causing the second adhesive layer 22 to overflow to other areas that do not need to be bonded.

[0053] In this embodiment, the thickness dimension t4 of the second adhesive layer 22 in the first direction can be any value or the range between any two values between 0.05 mm and 0.15 mm, such as 0.05 mm, 0.1 mm, 0.15 mm, etc.

[0054] In this embodiment, in order to confirm the influence of the thickness dimension t1 of the first protective matrix 11 in the first direction, the thickness dimension t2 of the second protective matrix 21 in the first direction, the thickness dimension t3 of the first adhesive layer 12 in the first direction, and the thickness dimension t4 of the second adhesive layer 22 in the first direction on the rapid exhaust and protection of the explosion-proof valve protection piece, as shown in Table 1, six groups of embodiments and six groups of comparative examples are provided to verify it.

[0055] When verifying the protection performance, first bond the explosion-proof valve protection piece and then sprinkle waste electrolyte on it. If no electrolyte is found on the surface of the explosion-proof valve, the protection performance is qualified. If electrolyte is found on the surface of the explosion-proof valve, the protection performance is unqualified. When verifying the exhaust performance, inject pressure gas that can open the explosion-proof valve into the closed battery housing. If the time for the explosion-proof valve protection piece to be opened is less than 0.1 s, the requirement for rapid exhaust is met. If the time for the explosion-proof valve protection piece to be opened is greater than 0.1 s, the requirement for rapid exhaust is not met. And observe the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. If the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22 still remain bonded after the explosion-proof valve protection piece is opened, the bonding strength meets the requirements. If the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22 are separated, the requirement for bonding strength is not met.

[0056] Table 1

[0057]

[0058] In Embodiment 1, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.05 mm, meeting the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.05 mm, meeting the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.05 mm, meeting the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.05 mm, meeting the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. And when the pressure gas opens the explosion-proof valve, the time taken to break through the protection piece of the explosion-proof valve is 0.02 s, which is less than the specified 0.1 s. Also, after the test, no separation occurs in the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Therefore, the requirements for rapid exhaust and protection are met, and the product is qualified.

[0059] In Embodiment 2, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.1 mm, meeting the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.1 mm, meeting the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.07 mm, meeting the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.07 mm, meeting the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. And when the pressure gas opens the explosion-proof valve, the time taken to break through the protection piece of the explosion-proof valve is 0.03 s, which is less than the specified 0.1 s. Also, after the test, no separation occurs in the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Therefore, the requirements for rapid exhaust and protection are met, and the product is qualified.

[0060] In Embodiment 3, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.15 mm, meeting the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.15 mm, meeting the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.09 mm, meeting the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.09 mm, meeting the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. And when the pressure gas opens the explosion-proof valve, the time taken to break through the explosion-proof valve protection piece is 0.05 s, which is less than the specified 0.1 s. Also, after the test, no separation occurs in the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Therefore, the requirements for rapid exhaust and protection are met, and the product is qualified.

[0061] In Embodiment 4, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.2 mm, meeting the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.2 mm, meeting the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.11 mm, meeting the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.11 mm, meeting the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. And when the pressure gas opens the explosion-proof valve, the time taken to break through the explosion-proof valve protection piece is 0.06 s, which is less than the specified 0.1 s. Also, after the test, no separation occurs in the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Therefore, the requirements for rapid exhaust and protection are met, and the product is qualified.

[0062] In Embodiment 5, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.25 mm, meeting the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.25 mm, meeting the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.13 mm, meeting the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.13 mm, meeting the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. And when the pressure gas opens the explosion-proof valve, the time taken to break through the protection piece of the explosion-proof valve is 0.08 s, which is less than the specified 0.1 s. And after the test, no separation occurs in the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Therefore, the requirements for rapid exhaust and protection are met, and the product is qualified.

[0063] In Embodiment 6, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.3 mm, meeting the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.3 mm, meeting the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.15 mm, meeting the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.15 mm, meeting the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. And when the pressure gas opens the explosion-proof valve, the time taken to break through the protection piece of the explosion-proof valve is 0.09 s, which is less than the specified 0.1 s. And after the test, no separation occurs in the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Therefore, the requirements for rapid exhaust and protection are met, and the product is qualified.

[0064] As can be seen from Embodiments 1 to 6, when the thickness dimension t1 of the first protective matrix 11 in the first direction, the thickness dimension t2 of the second protective matrix 21 in the first direction, the thickness dimension t3 of the first adhesive layer 12 in the first direction, and the thickness dimension t4 of the second adhesive layer 22 in the first direction all meet their respective size limit requirements, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. And when the pressure gas opens the explosion-proof valve, the time taken to break through the protection piece of the explosion-proof valve is less than the specified 0.1 s. And after the test, no separation occurs in the areas where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Therefore, the requirements for rapid exhaust and protection are met, and the product is qualified.

[0065] In Comparative Example 1, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.03 mm, which does not meet the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.2 mm, which meets the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.11 mm, which meets the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.11 mm, which meets the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, electrolyte is found on the surface of the explosion-proof valve. When the pressure gas blows open the explosion-proof valve, the time taken to break through the protection piece of the explosion-proof valve is 0.01 s, which is less than the specified 0.1 s. After the test, no separation occurs in the area where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Since electrolyte is found on the surface of the explosion-proof valve, it does not meet the protection requirement, and the product is unqualified.

[0066] In Comparative Example 2, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.5 mm, which does not meet the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.25 mm, which meets the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.13 mm, which meets the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.13 mm, which meets the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. When the pressure gas blows open the explosion-proof valve, the time taken to break through the protection piece of the explosion-proof valve is 0.3 s, which is greater than the specified 0.1 s. After the test, no separation occurs in the area where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Since the time taken for the pressure gas to break through the protection piece of the explosion-proof valve is greater than the specified 0.1 s, it does not meet the requirement of rapid exhaust, and the product is unqualified.

[0067] As can be seen from Comparative Example 1 and Comparative Example 2, when the thickness dimension t1 of the first protective matrix 11 in the first direction is less than the minimum value of 0.05 mm ≤ t1 ≤ 0.3 mm, at this time, due to the too thin thickness of the first protective matrix 11, the pressure gas can easily push open the explosion-proof valve protection sheet. Compared with Example 4, its breaking time is shorter and the exhaust is more rapid. However, when pouring waste electrolyte on the explosion-proof valve protection sheet, although the electrolyte is buffered and blocked by the second protective matrix 21, reducing the impact force, due to the too small thickness of the first protective matrix 11, it is unable to offset the remaining impact force of the electrolyte, resulting in the first protective matrix 11 being broken through, so that the electrolyte falls on the surface of the explosion-proof valve. Therefore, it cannot effectively protect the explosion-proof valve, so it does not meet the requirements of protection, and the product is unqualified.

[0068] When the thickness dimension t1 of the first protective matrix 11 in the first direction is greater than the maximum value of 0.05 mm ≤ t1 ≤ 0.3 mm, at this time, due to the too thick thickness of the first protective matrix 11, when pouring waste electrolyte on the explosion-proof valve protection sheet, since the thickness of the second protective matrix 21 meets the set range and the thickness of the first protective matrix 11 exceeds the maximum value of the set range, it can completely offset the impact of the electrolyte and block the electrolyte, avoiding the electrolyte from falling onto the explosion-proof valve; however, due to the too large thickness of the first protective matrix 11, it is very difficult for the pressure gas to push open the explosion-proof valve protection sheet. Compared with Example 5, its breaking time is longer and exceeds the specified time. Therefore, it cannot meet the requirements of rapid exhaust, and the product is unqualified.

[0069] In Comparative Example 3, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.1 mm, meeting the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.03 mm, not meeting the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.07 mm, meeting the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.07 mm, meeting the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, electrolyte is found on the surface of the explosion-proof valve. When the pressure gas opens the explosion-proof valve, the time to break through the explosion-proof valve protection sheet is 0.01 s, which is less than the specified 0.1 s. After the test is over, no separation occurs in the area where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Since electrolyte is found on the surface of the explosion-proof valve, it does not meet the requirements of protection, and the product is unqualified.

[0070] In Comparative Example 4, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.15 mm, which meets the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.5 mm, which does not meet the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.09 mm, which meets the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.09 mm, which meets the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. When the pressure gas blows open the explosion-proof valve, the time taken to break through the explosion-proof valve protection piece is 0.3 s, which is greater than the specified 0.1 s. After the test, no separation is found in the area where the first protective matrix 11 and the second protective matrix 21 are bonded by the first adhesive layer 12 and the second adhesive layer 22. Since the time taken for the pressure gas to break through the explosion-proof valve protection piece is greater than the specified 0.1 s, the requirement for rapid exhaust is not met, and the product is unqualified.

[0071] It can be seen from Comparative Example 3 and Comparative Example 4 that when the thickness dimension t2 of the second protective matrix 21 in the first direction is less than the minimum value of 0.05 mm ≤ t1 ≤ 0.3 mm, at this time, due to the too thin thickness of the second protective matrix 21, the pressure gas easily blows open the explosion-proof valve protection piece. Compared with Example 2, the breakthrough time is shorter and the exhaust is faster. However, when pouring waste electrolyte on the explosion-proof valve protection piece, due to the too thin thickness of the second protective matrix 21, the buffering force on the electrolyte is small, resulting in the first protective matrix 11 receiving too much impact and finally being broken through, causing the electrolyte to fall on the surface of the explosion-proof valve. Therefore, it cannot effectively protect the explosion-proof valve, and thus does not meet the protection requirement, and the product is unqualified.

[0072] When the thickness dimension t2 of the second protective matrix 21 in the first direction is greater than the maximum value of 0.05 mm ≤ t2 ≤ 0.3 mm, at this time, due to the too thick thickness of the second protective matrix 21, when pouring waste electrolyte on the explosion-proof valve protection piece, since the thickness of the second protective matrix 21 exceeds the maximum value of the set range and the thickness of the first protective matrix 11 meets the set range, the impact of the electrolyte can be completely offset, blocking the electrolyte and preventing it from falling onto the explosion-proof valve. However, due to the too large thickness of the second protective matrix 21, it is difficult for the pressure gas to blow open the explosion-proof valve protection piece. Compared with Example 3, the breakthrough time is longer and exceeds the specified time. Therefore, the requirement for rapid exhaust cannot be met, and the product is unqualified.

[0073] In Comparative Example 5, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.25 mm, meeting the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.25 mm, meeting the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.02 mm, not meeting the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.13 mm, meeting the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. When the pressure gas opens the explosion-proof valve, the time taken to break through the explosion-proof valve protection piece is 0.06 s, which is less than the specified 0.1 s. After the test, the first protective matrix 11 shows a detachment phenomenon, while the second protective matrix 21 does not show a detachment phenomenon. Due to the detachment of the first protective matrix 11, it is proved that the bonding strength is weak, the explosion-proof valve protection piece is prone to falling off, and the structural reliability is poor.

[0074] In Comparative Example 6, the thickness dimension t1 of the first protective matrix 11 in the first direction is set to 0.3 mm, meeting the range requirement of 0.05 mm ≤ t1 ≤ 0.3 mm. The thickness dimension t2 of the second protective matrix 21 in the first direction is set to 0.3 mm, meeting the range requirement of 0.05 mm ≤ t2 ≤ 0.3 mm. The thickness dimension t3 of the first adhesive layer 12 in the first direction is set to 0.15 mm, meeting the range requirement of 0.05 mm ≤ t3 ≤ 0.15 mm. The thickness dimension t4 of the second adhesive layer 22 in the first direction is set to 0.02 mm, not meeting the range requirement of 0.05 mm ≤ t4 ≤ 0.15 mm. At this time, after the detection test, no electrolyte is found on the surface of the explosion-proof valve. When the pressure gas opens the explosion-proof valve, the time taken to break through the explosion-proof valve protection piece is 0.08 s, which is less than the specified 0.1 s. After the test, the second protective matrix 21 shows a detachment phenomenon, while the first protective matrix 11 does not show a detachment phenomenon. Due to the detachment of the second protective matrix 21, it is proved that the bonding strength is weak, the explosion-proof valve protection piece is prone to splitting, resulting in the detachment of the outer patch 2, and the structural reliability is poor.

[0075] As can be seen from Comparative Example 5 to Comparative Example 6, when the thickness dimension t3 of the first adhesive layer 12 in the first direction is less than the minimum value of 0.05 mm ≤ t3 ≤ 0.15 mm, the bonding strength of the first adhesive layer 12 to the first protective matrix 11 is poor at this time. Since the first protective matrix 11 belongs to the inner patch 1, once the first protective matrix 11 falls off, the entire explosion-proof valve protection piece will fall off. Therefore, its structural reliability is poor and it cannot achieve an effective protection effect. When the thickness dimension t4 of the second adhesive layer 22 in the first direction is less than the minimum value of 0.05 mm ≤ t4 ≤ 0.15 mm, the bonding strength of the second adhesive layer 22 to the second protective matrix 21 is poor at this time. Since the second protective matrix 21 belongs to the outer patch 2, once the second protective matrix 21 falls off, the explosion-proof valve protection piece will split, causing the explosion-proof valve to rely only on the first protective matrix 11 on the inner patch 1 for protection. Since there is only one layer of the first protective matrix 11, it is easily broken when subjected to impact. Therefore, it also cannot achieve an effective protection effect.

[0076] Optionally, a first color coating is applied to the outside of the first protective matrix 11, and a second color coating is applied to the outside of the second protective matrix 21. The colors of the first color coating and the second color coating are different. By applying the first color coating to the outside of the first protective matrix 11 and the second color coating to the outside of the second protective matrix 21, it can be clearly and intuitively recognized whether the explosion-proof valve protection piece is installed during assembly, avoiding the problem of missing installation, and making the colors of the first color coating and the second color coating different, thereby ensuring the accuracy of the installation positions of the inner patch 1 and the outer patch 2 and avoiding installation errors. In this embodiment, the colors of the first color coating and the second color coating can be freely set according to requirements, such as highly recognizable colors like green and red.

[0077] In this embodiment, as Figure 5 shown, a battery cover plate is also provided. The battery cover plate includes a cover plate body 100, an explosion-proof valve, and the above-mentioned explosion-proof valve protection piece. An installation hole is formed in the cover plate body 100. The explosion-proof valve is arranged in the installation hole. The explosion-proof valve protection piece is connected to the cover plate body 100 and is used to close the installation hole. By applying the above-mentioned explosion-proof valve protection piece, the battery cover plate not only avoids the explosion-proof valve from being eroded by external dust and electrolyte, improves the product quality, but also ensures rapid exhaust during thermal runaway, improving the safety of the product.

[0078] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. Explosion-proof valve protection piece, characterized in that, The explosion-proof valve protection piece includes: An inner patch, the inner patch includes a first protection matrix and a first adhesive layer, the first adhesive layer is continuously arranged around the circumferential edge of the first protection matrix, and is used to fix the first protection matrix; An outer patch, the outer patch includes a second protection matrix and a second adhesive layer, the second adhesive layer is continuously arranged around the circumferential edge of the second protection matrix, and is used to bond the second protection matrix to the side of the first protection matrix facing away from the explosion-proof valve.

2. The explosion-proof valve protection piece according to claim 1, wherein, A plurality of first exhaust structures are provided on the first protection matrix at intervals.

3. The explosion-proof valve protection piece according to claim 2, wherein, A plurality of second exhaust structures are provided on the second protection matrix at intervals, and the plurality of second exhaust structures are arranged staggered with the plurality of first exhaust structures.

4. The explosion-proof valve protection piece according to claim 3, characterized in that Both the first exhaust structure and the second exhaust structure are through-hole structures, and the cross-section of the through-hole structure is circular or oval or polygonal.

5. The explosion-proof valve protection piece according to claim 1, characterized in that, The thickness dimension of the first protection matrix in the first direction is t1, and satisfies 0.05mm ≤ t1 ≤ 0.3mm; And / or, the thickness dimension of the second protection matrix in the first direction is t2, and satisfies 0.05mm ≤ t2 ≤ 0.3mm.

6. The explosion-proof valve protection piece according to claim 1, wherein, The thickness dimension of the first adhesive layer in the first direction is t3, and satisfies 0.05mm ≤ t3 ≤ 0.15mm; And / or, the thickness dimension of the second adhesive layer in the first direction is t4, and satisfies 0.05mm ≤ t4 ≤ 0.15mm.

7. The explosion-proof valve protection sheet according to claim 1, characterized in that A first color coating is coated on the outside of the first protection matrix, a second color coating is coated on the outside of the second protection matrix, and the colors of the first color coating and the second color coating are different.

8. The explosion-proof valve protection piece according to claim 1, characterized in that, The first protection matrix and the second protection matrix are prepared from PET, PC, PP, PVC or PE materials.

9. The explosion-proof valve protection piece according to claim 1, wherein, The first adhesive layer and the second adhesive layer are prepared from pressure-sensitive adhesive or heat-sensitive adhesive.

10. Battery cover plate, characterized in that, The battery cover plate includes a cover plate body, an explosion-proof valve and an explosion-proof valve protection piece as described in any one of claims 1-9, an installation hole is provided on the cover plate body, the explosion-proof valve is arranged in the installation hole, and the explosion-proof valve protection piece is connected to the cover plate body and is used to close the installation hole.

Images