A cover plate and a battery comprising the same

Abstract

The utility model relates to a kind of cover plates, first score and second score are sequentially arranged from center to edge on the cover plate, the first score forms first explosion-proof valve on the cover plate, the second score forms second explosion-proof valve on the cover plate;Wherein, the opening valve pressure of the first explosion-proof valve is lower than the opening valve pressure of the second explosion-proof valve.In the cover plate of the utility model, the synergistic effect of first explosion-proof valve and second explosion-proof valve greatly shortens the pressure relief response time, can more timely discharge the high-pressure gas in the battery cell, effectively prevent the battery cell from exploding or rupturing due to excessive pressure, significantly improve the safety of battery under extreme conditions.

Description

Technical Field

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

[0002] When power batteries (especially lithium-ion batteries) undergo cyclic charging and discharging or experience thermal runaway, a large amount of gas is generated inside, causing the internal pressure of the casing to rise rapidly. To release this pressure, the industry commonly installs explosion-proof valves (also known as safety valves or pressure relief valves) on the battery end caps. A common explosion-proof valve structure consists of an annular thinning area (score) stamped into a metal cover plate. When the internal pressure reaches a set threshold, the thinning area ruptures, allowing the gas to escape rapidly, thereby preventing the cell from exploding.

[0003] Most explosion-proof valves on the market currently adopt a "single-stage" design, meaning they only have one groove as the sole pressure relief path. While this structure is simple, it has the following drawbacks in practical use: Firstly, when the battery is under long-term cycling conditions, trace amounts of gas accumulate continuously inside, causing the cover plate to bulge and deform. Because the opening pressure of a single-stage explosion-proof valve must match the highest pressure during thermal runaway, which is much higher than the bulging pressure caused by gas generation during cycling, the valve body cannot open in time during the cycling phase, and the bulging deformation will continue to intensify. The bulging deformation of the cover plate will exert a continuous tensile force on the weld area between the cover plate and the shell, eventually leading to weld cracking and electrolyte leakage. Secondly, in thermal runaway scenarios, a huge amount of gas is generated inside the battery cell in a short period of time. Because the single-stage explosion-proof valve must withstand the entire pressure load at once, the valve plate rupture is significantly delayed, resulting in a long pressure relief response time. Delayed pressure relief will cause the internal pressure to increase further, posing a risk of shell rupture.

[0004] To address the aforementioned shortcomings, some existing technologies attempt to shorten the response time by reducing the opening pressure of the single-stage explosion-proof valve. However, this approach introduces new problems: with a reduced opening pressure, even slight gas generation during the circulation phase can trigger the explosion-proof valve, leading to premature electrolyte leakage and severely impacting battery life and safety.

[0005] Another technology proposes to install multiple independent explosion-proof valves on the cover plate, but there is a lack of a coordinated pressure relief mechanism between the explosion-proof valves, making it impossible to respond step by step according to the pressure level, and it is still difficult to take into account the differentiated needs of the two working conditions of cyclic expansion and thermal runaway.

[0006] Therefore, existing technologies have not yet solved the contradiction of "how to make the explosion-proof valve avoid weld cracking caused by bulging during the circulation stage and open quickly during the thermal runaway stage", and there is an urgent need for a new type of cover plate structure that can respond in stages and release pressure step by step. Utility Model Content

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing a cover plate and a battery including the cover plate.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] The first aspect of this utility model is to provide a cover plate, wherein a first groove and a second groove are sequentially provided on the cover plate from the center to the edge, the first groove forming a first explosion-proof valve on the cover plate, and the second groove forming a second explosion-proof valve on the cover plate; wherein...

[0010] The opening pressure of the first explosion-proof valve is lower than that of the second explosion-proof valve.

[0011] Preferably, the opening pressure of the first explosion-proof valve is 0.8MPa-2.0MPa.

[0012] Preferably, the opening pressure of the second explosion-proof valve is 1.4MPa-4.0MPa.

[0013] Preferably, a reinforcing rib is provided between the first groove and the second groove to further enhance the structural strength of the cover plate and extend the battery's service life.

[0014] Preferably, the first notch is provided on the outer surface of the cover plate, and the first notch is provided facing the inner surface of the cover plate.

[0015] Preferably, the first notch is provided on the inner surface of the cover plate, and the first notch is provided facing the outer surface of the cover plate.

[0016] Preferably, the second notch is provided on the outer surface of the cover plate, and the second notch is provided facing the inner surface of the cover plate.

[0017] Preferably, the second notch is provided on the inner surface of the cover plate, and the second notch is provided facing the outer surface of the cover plate.

[0018] Preferably, the cross-sectional shape of the first notch and the cross-sectional shape of the second notch are each independently selected from one of the following: rectangle, trapezoid, or triangle.

[0019] A second aspect of this utility model is to provide a battery, comprising: a cover plate as described above.

[0020] The present invention adopts the above technical solution and has the following technical effects compared with the prior art:

[0021] When thermal runaway occurs in a battery cell, internal gas is rapidly generated, and the pressure rises quickly. At this time, the first explosion-proof valve of the cover plate of this invention can open quickly, not only releasing a large amount of gas in time and alleviating the bulging and deformation of the cover plate, but also forming a local high-pressure area on the inner side of the cover plate, prompting the second explosion-proof valve to respond and open quickly. The synergistic effect of the first and second explosion-proof valves significantly shortens the pressure relief response time, enabling more timely discharge of high-pressure gas inside the battery cell, effectively preventing the battery cell from exploding or rupturing due to excessive pressure, and significantly improving the safety of the battery under extreme conditions. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the cover plate in this utility model;

[0023] Figure 2-4 This is a structural schematic diagram showing the cross-sectional shape of the first or second notch in this utility model;

[0024] Figure 5 This is a cross-sectional view of the cover plate when the first notch breaks in this utility model.

[0025] Figure 6 This is a cross-sectional view of the cover plate when the second notch breaks in this utility model.

[0026] The reference numerals in the figures include:

[0027] Cover plate 1; First notch 11; Second notch 12; Reinforcing rib 13. Detailed Implementation

[0028] The specific embodiments of this utility model will be described in detail below.

[0029] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning as understood by one of ordinary skill in the art to which this utility model pertains.

[0030] The word "comprising" or similar terms used in this utility model patent application specification and claims mean that the objects preceding "comprising" include the objects listed after "comprising" or their equivalents, and do not exclude other objects.

[0031] The numerical values ​​mentioned in this invention include all values ​​increasing one unit at a time from low to high, assuming that there is at least a two-unit interval between any lower and higher value. For example, if a component quantity or a physical quantity is said to be better from 1 to 100, 10 to 90, and 20 to 80, it means that values ​​such as 5 to 95, 14 to 76, 23 to 67, 32 to 58, and 41 to 49 are clearly listed in this specification; for values ​​less than 1, 0.0001, 0.001, 0.01, or 0.1 are considered suitable units. The foregoing examples are for illustrative purposes only; in practice, all combinations of values ​​between the lowest and highest listed values ​​are considered to be clearly listed in this specification in a similar manner.

[0032] Example 1

[0033] like Figure 1 As shown, this embodiment provides a cover plate 1. From the center to the edge, the cover plate 1 is sequentially provided with a first notch 11, a reinforcing rib 13, and a second notch 12. The first notch 11 forms a first closed curve on the cover plate 1 to form a first explosion-proof valve, and the second notch 12 forms a second closed curve on the cover plate 1 to form a second explosion-proof valve; wherein,

[0034] The opening pressure of the first explosion-proof valve is lower than that of the second explosion-proof valve.

[0035] It is obvious to those skilled in the art that the cover plate 1 is integrally formed with the first notch 11 and the cover plate 1 is integrally formed with the second notch 12.

[0036] The first notch 11 and the second notch 12 are independently provided on the outer surface or the inner surface of the cover plate 1, that is, the first notch 11 and the second notch 12 can be provided on the same surface of the cover plate 1 or on different surfaces of the cover plate 1.

[0037] In some preferred embodiments, the first notch 11 is provided on the outer surface of the cover plate 1, and the first notch 11 is disposed towards the inner surface of the cover plate 1; the second notch 12 is provided on the outer surface of the cover plate 1, and the second notch 12 is disposed towards the inner surface of the cover plate 1.

[0038] In some preferred embodiments, the first notch 11 is provided on the inner surface of the cover plate 1, and the first notch 11 is disposed facing the outer surface of the cover plate 1; the second notch 12 is provided on the inner surface of the cover plate 1, and the second notch 12 is disposed facing the outer surface of the cover plate 1.

[0039] In some preferred embodiments, the first notch 11 is provided on the outer surface of the cover plate 1, and the first notch 11 is provided facing the inner surface of the cover plate 1; the second notch 12 is provided on the inner surface of the cover plate 1, and the second notch 12 is provided facing the outer surface of the cover plate 1.

[0040] In some preferred embodiments, the first notch 11 is provided on the inner surface of the cover plate 1, and the first notch 11 is provided facing the outer surface of the cover plate 1; the second notch 12 is provided on the outer surface of the cover plate 1, and the second notch 12 is provided facing the inner surface of the cover plate 1.

[0041] In some preferred embodiments, the first closed curve is a circular closed curve.

[0042] In some preferred embodiments, the first closed curve is an elliptical closed curve.

[0043] In some preferred embodiments, the first closed curve is a racetrack-shaped closed curve.

[0044] The cross-sectional shape of the first notch 11 and the cross-sectional shape of the second notch 12 are each independently selected from one of the following: rectangle, trapezoid, or triangle. That is, the cross-sectional shape of the first notch 11 and the cross-sectional shape of the second notch 12 can be the same or different.

[0045] In some preferred embodiments, the cross-sectional shape of the first notch 11 is as follows: Figure 2 The rectangle shown;

[0046] In some preferred embodiments, the cross-sectional shape of the first notch 11 is as follows: Figure 3 The trapezoid shown;

[0047] In some preferred embodiments, the cross-sectional shape of the first notch 11 is as follows: Figure 4 The triangle shown;

[0048] In some preferred embodiments, the cross-sectional shape of the second notch 12 is as follows: Figure 2 The rectangle shown;

[0049] In some preferred embodiments, the cross-sectional shape of the second notch 12 is as follows: Figure 3 The trapezoid shown;

[0050] In some preferred embodiments, the cross-sectional shape of the second notch 12 is as follows: Figure 4 The triangle shown.

[0051] In some preferred embodiments, the opening pressure of the first explosion-proof valve is 0.8 MPa-2.0 MPa;

[0052] In some preferred embodiments, the opening pressure of the second explosion-proof valve is 1.4 MPa-4.0 MPa.

[0053] In some more preferred embodiments, the opening pressure of the first explosion-proof valve is 0.8 MPa, and the opening pressure of the second explosion-proof valve is 1.4 MPa.

[0054] In some more preferred embodiments, the opening pressure of the first explosion-proof valve is 1.4 MPa, and the opening pressure of the second explosion-proof valve is 2.7 MPa.

[0055] In some preferred embodiments, the opening pressure of the first explosion-proof valve is 2.0 MPa, and the opening pressure of the second explosion-proof valve is 4.0 MPa.

[0056] Example 2

[0057] This embodiment provides a battery, including: a casing, and a cover plate 1 welded to an opening in the casing; wherein,

[0058] The cover plate 1 is as described in Example 1.

[0059] During the thermal runaway phase of a battery cell, the internal gas increases rapidly, and the pressure rises quickly.

[0060] When the pressure exceeds the opening pressure of the first explosion-proof valve, the first notch 11 ruptures rapidly and releases a large amount of gas, such as Figure 5 As shown;

[0061] Subsequently, the high-pressure airflow concentrates on the second explosion-proof valve, and the second notch 12 immediately ruptures under the concentrated load, forming a larger pressure relief channel, such as Figure 6 As shown;

[0062] The internal pressure of the battery cell can be reduced to a safe range in a timely manner, preventing the casing from bursting and significantly improving the safety of the battery under extreme conditions.

[0063] The above description is only a preferred embodiment of the present utility model and does not limit the implementation method and protection scope of the present utility model. Those skilled in the art should realize that all solutions obtained by equivalent substitutions and obvious changes made based on the description and illustrations of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A cover plate (1), characterized in that, The cover plate (1) has a first groove (11) and a second groove (12) arranged sequentially from the center to the edge. The first groove (11) forms a first explosion-proof valve on the cover plate (1), and the second groove (12) forms a second explosion-proof valve on the cover plate (1). The opening pressure of the first explosion-proof valve is lower than that of the second explosion-proof valve.

2. The cover plate (1) according to claim 1, characterized in that, The opening pressure of the first explosion-proof valve is 0.8MPa-2.0MPa.

3. The cover plate (1) according to claim 1, characterized in that, The opening pressure of the second explosion-proof valve is 1.4MPa-4.0MPa.

4. The cover plate (1) according to claim 1, characterized in that, A reinforcing rib (13) is also provided between the first notch (11) and the second notch (12).

5. The cover plate (1) according to claim 1, characterized in that, The first notch (11) is provided on the outer surface of the cover plate (1), and the first notch (11) is provided facing the inner surface of the cover plate (1).

6. The cover plate (1) according to claim 1, characterized in that, The first notch (11) is provided on the inner surface of the cover plate (1), and the first notch (11) is provided facing the outer surface of the cover plate (1).

7. The cover plate (1) according to claim 1, characterized in that, The second groove (12) is provided on the outer surface of the cover plate (1), and the second groove (12) is provided facing the inner surface of the cover plate (1).

8. The cover plate (1) according to claim 1, characterized in that, The second groove (12) is provided on the inner surface of the cover plate (1), and the second groove (12) is provided facing the outer surface of the cover plate (1).

9. The cover plate (1) according to claim 1, characterized in that, The cross-sectional shape of the first notch (11) and the cross-sectional shape of the second notch (12) are independently selected from one of the following: rectangle, trapezoid, or triangle.

10. A battery, characterized in that, include: The cover plate (1) as described in any one of claims 1-9.

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