Battery shell with enhanced integrated anti-explosion valve structure and secondary battery

Abstract

The utility model discloses a battery shell with an enhanced integrated explosion-proof valve structure and a secondary battery, the battery shell comprises a shell, an explosion-proof nick is formed on the outer surface or the inner surface of the shell through etching, and a reinforcing band is fixedly arranged on the outer surface or the inner surface of the shell corresponding to the outer side of the explosion-proof nick. According to the utility model, the reinforcing band is fixedly arranged on the outer side of the explosion-proof nick, so that the strength of the shell in the area where the reinforcing band is located can be enhanced, the area is prevented from being torn in the explosion process of the explosion-proof nick, and the tearing range of the explosion-proof nick can be limited through the reinforcing band; and the damage to the adjacent battery due to the overlarge tearing range of the anti-explosion nick is avoided.

Description

TECHNICAL FIELD

[0001] The utility model belongs to secondary battery field, especially, a kind of battery shell with reinforced integrated explosion-proof valve structure. BACKGROUND

[0002] At present, secondary battery is widely used in new energy field as the power source of pure electric vehicle, plug-in hybrid electric vehicle and electric bicycle etc.. Current secondary battery has begun to use relatively thin stainless steel material as shell material to save material cost and reduce the occupied space of battery shell, and directly make explosion-proof notch on stainless steel shell as integrated explosion-proof valve;So as to simplify the manufacturing process of explosion-proof structure, avoid the influence of poor welding effect on the explosion-proof effect of explosion-proof structure.

[0003] However, the integrated structure of explosion-proof notch still has the following problems: if the explosion-proof notch adopts the shape of closed curve, the area enclosed by the explosion-proof notch is easy to be blown away by high pressure as a whole and cause secondary damage to the surrounding devices, and if the explosion-proof notch adopts the shape of non-closed curve with a notch, although the notch will not tear when exploding, the area enclosed by the explosion-proof notch will tear outward from the notch, and since the tearing strength is difficult to control accurately, when the tearing amplitude is large, it will still cause damage to the adjacent normal battery. SUMMARY

[0004] In view of the above technical problems of the prior art, the utility model provides a battery shell with enhanced integrated explosion-proof valve structure.

[0005] To solve the above technical problems, the utility model provides the following technical scheme:

[0006] A battery shell with enhanced integrated explosion-proof valve structure, comprising a shell, an explosion-proof notch is provided on the outer surface or inner surface of the shell, and a reinforcing band is fixedly provided on the outer side of the explosion-proof notch on the outer surface or inner surface of the shell.

[0007] Further, the explosion-proof notch is a non-closed curve with a notch, thereby forming a tearing area around the notch, the reinforcing band is a straight band structure or a curved band structure provided on the outer surface or inner surface of the shell, and the reinforcing band truncates the tearing area of the explosion-proof notch.

[0008] Further, the reinforcing band is a closed band structure, and the explosion-proof notch is arranged in the area enclosed by the band structure.

[0009] Further, the reinforcing band is a circular ring structure, an elliptical ring structure or a ring structure in the shape of a racetrack.

[0010] Further, the shell is a cuboid cylindrical structure, comprising two opposite wide sides and two opposite narrow sides, and the reinforcing band and the explosion-proof notch are arranged on one narrow side.

[0011] Further, the explosion-proof notch comprises a first notch in the shape of a continuous line; the shape of the first notch is a combination of one or more of a circular arc, an elliptical arc, a spline curve and a straight line segment, and the first end and the tail end of the first notch are not connected.

[0012] Further, the explosion-proof notch further comprises a plurality of second notches arranged along the length direction of the first notch and overlapping thereon, and the notch residual value of the second notch is less than that of the first notch.

[0013] Further, the shell is made of stainless steel material with a thickness of 0.15mm-0.3mm, and the reinforcing band is made of stainless steel material with a thickness of 0.15mm-0.3mm; the notch residual value at the position where the second notch is not arranged on the first notch is 0.10mm-0.15mm; the notch residual value at the position where the second notch is arranged on the first notch is 0.03mm-0.09mm.

[0014] Further, the first notch comprises a first curve notch, a second curve notch and a connecting notch, the first end of the connecting notch is connected with the second end of the first curve notch, the second end of the connecting notch is connected with the first end of the second curve notch, and the first end of the first curve notch and the second end of the second curve notch are not connected, thereby forming a gap between the first curve notch and the second curve notch.

[0015] The first curvature radius threshold and the second curvature radius threshold are preset, the first curvature radius threshold is greater than the second curvature radius threshold; the shape of the first curve notch and the second curve notch is a curve with a maximum curvature radius less than the second curvature radius threshold, and the shape of the connecting notch is a straight line segment or a curve with a minimum curvature radius greater than the first curvature radius threshold.

[0016] Further, the shape of the first curve notch and the second curve notch is a circular arc, an elliptical arc or a planar spiral line, and the angle of the first curve notch and the second curve notch is greater than or equal to 180°.

[0017] A secondary battery comprising a battery shell with a reinforced integrated explosion-proof valve structure.

[0018] The utility model discloses a reinforcing belt is fixedly arranged on the outside of the explosion -proof score, can strengthen the shell strength of the area where the reinforcing belt is, to avoid the area being torn in the blasting process of the explosion -proof score, can limit the tearing range of the explosion -proof score through the reinforcing belt, avoid the tearing range of the explosion -proof score being too big and damaging adjacent battery. The reinforcing belt is designed as closed belt structure, can also strengthen the shell strength of the periphery of the explosion -proof score, thereby increasing the structural strength of the shell, avoiding the deformation of the shell due to expansion, guaranteeing the consistency of valve opening. In addition, the first score adopts the structure that the head and tail are concave inward, and a plurality of second scores are overlapped on the first score and form the shape similar to dot dash line, the size of the tear opening when blasting is reduced through the first score, through the selection of the position, quantity, score residual value and length of the second score, the tearing difficulty of small curvature area can be selectively reduced, and the insufficient blasting condition is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0019] The drawings described herein are used to provide further understanding of the present application, and form a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0020] Figure 1 It is an embodiment structure schematic view of the battery shell with the enhanced integrated explosion -proof valve structure.

[0021] Figure 2 It is another embodiment structure schematic view of the battery shell with the enhanced integrated explosion -proof valve structure.

[0022] Figure 3 It is a structure schematic view of the first score in the embodiment.

[0023] Figure 4 It is a distribution schematic view of the second score in the embodiment.

[0024] Figure 5 It is a structure schematic view of the explosion -proof score formed by the overlapping of the second score on the first score.

[0025] The description of the drawings is as follows:

[0026] Shell - 100, wide side - 101, narrow side - 102, reinforcing belt - 200, explosion -proof score - 300, first score - 310, first curve score - 311, second curve score - 312, connecting score - 313, second score - 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 331, notch - 340, tearing area - 350. DETAILED DESCRIPTION

[0027] The embodiments of the present application are described below with specific examples. The drawings provided in the following examples only schematically illustrate the basic concept of the present application, and the features in the following examples and embodiments can be combined with each other without conflict.

[0028] Please refer to Figure 1 , Figure 1 The present application is a battery shell with enhanced integrated explosion-proof valve structure. The battery shell with enhanced integrated explosion-proof valve structure includes a shell 100, and an explosion-proof notch 300 is formed on the outer surface of the shell 100, thereby forming an integrated explosion-proof valve structure through the explosion-proof notch 300. A reinforcing band 200 is also fixedly arranged on the outer surface of the shell 100 corresponding to the outer side of the explosion-proof notch 300. Of course, the explosion-proof notch 300 and the reinforcing band 200 can also be arranged on the inner surface of the shell 100. The explosion-proof notch 300 is generally formed by laser etching, and of course, the explosion-proof notch 300 can also be formed by stamping or other methods. The reinforcing band 200 is generally fixed on the shell 100 by welding, and of course, the reinforcing band 200 can also be fixed on the shell 100 by adhesion or other methods.

[0029] When the battery internal cell is damaged and emits a large amount of heat and / or releases gas, the pressure inside the shell 100 expands rapidly. When the explosion-proof notch 300 is arranged on the shell 100, if the internal pressure of the shell 100 is too large, as the pressure increases, the explosion-proof notch 300 will be torn under the action of high pressure, allowing the high-pressure gas inside the shell 100 to be discharged from the torn opening, thereby rapidly reducing the internal pressure of the shell 100 and preventing the battery from exploding, thereby protecting the personal safety of the producer and user. The reinforcing band 200 is used to strengthen the strength of the shell 100 in the area, so as to avoid the area being torn in the explosion process of the explosion-proof notch 300, thereby limiting the tearing range of the explosion-proof notch 300 through the reinforcing band 200, and avoiding the tearing range of the explosion-proof notch 300 being too large to damage the shell of the adjacent battery.

[0030] In this embodiment, the shell 100 adopts a cuboid cylinder structure. This kind of shell 100 can be used to produce blade batteries, square batteries and the like, so as to save the occupied space when assembling single batteries into a battery pack. At this time, the shell 100 includes two oppositely arranged wide sides 101 and two oppositely arranged narrow sides 102. The reinforcing band 200 and the explosion-proof notch 300 are generally arranged on one of the narrow sides 102. Of course, the shell 100 can also be a cylinder or other cylindrical structure. The shell 100 is made of stainless steel with a thickness of 0.15mm to 0.3mm, and the reinforcing band 200 is also made of stainless steel with a thickness of 0.15mm to 0.3mm. In this embodiment, the wall thickness of the stainless steel used in the shell 100 and the reinforcing band 200 is 0.18mm±0.005mm. Of course, the shell 100 and the reinforcing band 200 can also be made of aluminum alloy. When aluminum alloy is used, the wall thickness of the shell 100 and the reinforcing band 200 will be much greater than when stainless steel is used.

[0031] In this embodiment, the reinforcing band 200 adopts a closed band structure, and the explosion-proof notch 300 is arranged in the area enclosed by the band structure. For example, the reinforcing band 200 can be a circular ring structure, an elliptical ring structure or a ring structure in the shape of a racetrack. Of course, the reinforcing band 200 can also adopt other closed regular or irregular graphic structures. The reinforcing band 200 adopts a closed ring band structure, which can not only limit the tearing range of the explosion-proof notch 300, but also strengthen the strength of the shell 100 around the explosion-proof notch 300, thereby increasing the structural strength of the shell 100, avoiding deformation of the shell 100 due to expansion, and ensuring the consistency of the valve opening.

[0032] Of course, please refer to Figure 2 Since the explosion-proof notch 300 generally adopts a non-closed curved shape with a notch 340 at present, thereby forming a tearing area 350 (i.e. an area that can be torn outward after the explosion-proof notch 300 is blown open) around the notch 340, since the tearing path of the explosion-proof notch 300 during explosion generally lies in the tearing area 350, in other embodiments, the reinforcing band 200 can also be a non-closed band structure, for example, the reinforcing band 200 can also be a straight or curved band structure arranged on the outer or inner surface of the shell 100, as long as the reinforcing band 200 is located at a position capable of intercepting the tearing area 350 of the explosion-proof notch 300, i.e. the side of the reinforcing band 200 close to the explosion-proof notch 300, so as to limit the tearing range of the explosion-proof notch 300 to the inside of the reinforcing band 200.

[0033] Please refer to Figure 3The explosion-proof score 300 includes a first score 310 in the shape of a continuous line. The first score 310 can be in the shape of one or a combination of a circular arc, an elliptical arc, a spline curve, and a straight line segment. When the explosion-proof score 300 is in the shape of a closed curve, the area enclosed by the explosion-proof score 300 is often torn as a whole and blown away by high pressure when the explosion-proof score 300 is torn due to the expansion of the gas inside the shell 100 caused by the heat of the battery cell, thereby easily causing secondary damage to other battery cells or the water-cooled plate and the surrounding connection circuit. Therefore, the first score 310 in the embodiment is in the shape of a first end and a tail end that do not connect to each other, thereby forming a gap 340 between the first end and the tail end of the first score 310 to avoid the area enclosed by the explosion-proof score 300 being torn as a whole, thereby avoiding secondary damage to the battery when the battery cell is heated.

[0034] For example, the first score 310 can include a first curved score 311, a second curved score 312, and a connecting score 313. The first end of the connecting score 313 is connected to the second end of the first curved score 311, and the second end of the connecting score 313 is connected to the first end of the second curved score 312. The first end of the first curved score 311 and the second end of the second curved score 312 do not connect to each other, thereby forming a gap 340 between the first curved score 311 and the second curved score 312. The first curved score 311 and the second curved score 312 are curves with a large radius of curvature, and the connecting score 313 is a straight line segment or a curve with a small radius of curvature. For example, a first radius of curvature threshold and a second radius of curvature threshold can be preset. The first radius of curvature threshold is greater than the second radius of curvature threshold. The first radius of curvature threshold is generally greater than the width (i.e., the length in the direction of the z-axis) of the narrow side 102 where the explosion-proof score 300 is located, and the second radius of curvature threshold is generally less than half the width of the narrow side 102 where the explosion-proof score 300 is located. The first curved score 311 and the second curved score 312 are in the shape of a curve with a maximum radius of curvature less than the second radius of curvature threshold, and the connecting score 313 is in the shape of a straight line segment or a curve with a minimum radius of curvature greater than the first radius of curvature threshold. Figure 1 The first curved score 311 and the second curved score 312 are in the shape of a curve with a maximum radius of curvature less than the second radius of curvature threshold, and the connecting score 313 is in the shape of a straight line segment or a curve with a minimum radius of curvature greater than the first radius of curvature threshold.

[0035] The first curved score 311 and the second curved score 312 are preferably in the shape of a circular arc, an elliptical arc, or a planar spiral. The connecting score 313 is preferably in the shape of a straight line segment, a circular arc with a radius greater than the first radius of curvature threshold, or an elliptical arc with a minimum radius of curvature greater than the first radius of curvature threshold.

[0036] In the embodiment, the first curved score line 311 and the second curved score line 312 are in the shape of a circular arc, and the connecting score line 313 is in the shape of a straight line segment. The angle of the first curved score line 311 and the second curved score line 312 is generally greater than or equal to 180°. By setting the angle of the first curved score line 311 and the second curved score line 312 to be greater than 180°, the leading end and the trailing end of the explosion-proof score line 300 are concave inward, so that a part of the impact force can be converted into an inward tearing force when the explosion-proof score line 300 is broken open, thereby offsetting a part of the outward tearing force and reducing the size of the tear gap. In the embodiment, the angle of the first curved score line 311 and the second curved score line 312 is preferably 240°.

[0037] Please refer to Figure 4 and Figure 5 In order to facilitate the control of the tearing range of the first score line 310, the explosion-proof score line 300 can further include a plurality of second score lines arranged along the length direction of the first score line 310 and overlapping the first score line 310, and the score residual value of the second score line is less than the score residual value of the first score line 310. The score residual value of the explosion-proof score line 300 is defined as the wall thickness of the shell 100 remaining after the shell 100 is thinned at the explosion-proof score line 300. In the embodiment, the score residual value of the first score line 310 where the second score line is not arranged overlappingly is 0.10mm-0.15mm; and the score residual value of the first score line 310 where the second score line is arranged overlappingly is 0.03mm-0.09mm. The explosion-proof score line 300 (i.e. the first score line 310 and the second score line) is generally a groove structure with a wide upper part and a narrow lower part. In the embodiment, the cross section of the first score line 310 and the second score line is a trapezoidal shape with a wide upper part and a narrow lower part.

[0038] If the value of the notch residual value of the explosion-proof notch 300 is small, the overall tearing gas pressure value of the explosion-proof notch 300 is small; when the battery is damaged and the explosion-proof notch 300 is opened, the resistance at the explosion-proof notch 300 is small, which is easy to cause the explosion-proof notch 300 to be completely opened, and the surrounding part of the explosion-proof notch 300 to tear open a larger opening in the shell 100 under the action of a large impact force, thereby causing damage to the adjacent battery shell 100. If the value of the notch residual value is large, when the internal gas pressure of the battery reaches the upper limit pressure, the explosion-proof notch 300 may not be able to tear open completely; thereby causing the pressure relief port formed at the explosion-proof notch 300 to be relatively small, which cannot timely discharge the gas inside the battery, and thus may cause the battery to over-expand, leading to an explosion. However, due to the many factors affecting the overall tearing gas pressure value of the explosion-proof notch 300, when the notch residual values at all parts of the explosion-proof notch 300 are the same, or when the notch residual values at all parts of the several large component regions of the explosion-proof notch 300 are the same, it is difficult to reduce the influence of other factors on the overall tearing gas pressure value of the explosion-proof notch 300, and to ensure that the explosion-proof notch 300 can be completely torn open and the reinforcing belt 200 in the torn region 350 will not be torn off.

[0039] In the present embodiment, by setting the first notch 310 and the second notch with different notch residual values, the tearing difficulty of the explosion-proof notch 300 can be overall improved by increasing the notch residual value at the first notch 310, and then adjusted by setting the second notch. By selecting the position, number, notch residual value and length of the second notch, the tearing difficulty of the explosion-proof notch 300 can be adjusted, making the adjustment of the tearing difficulty of the explosion-proof notch 300 more convenient and accurate, so that the tearing difficulty of the explosion-proof notch 300 can be selectively reduced in different regions. For example, longer second notches are generally set in regions with high tearing difficulty of the explosion-proof notch 300, and the notch residual value of the second notch in this region can be appropriately reduced, so that the tearing difficulty of the originally difficult-to-tear region of the explosion-proof notch 300 is reduced more greatly, and the tearing difficulty of each region of the explosion-proof notch 300 becomes more similar after adjustment. Further, the overall tearing gas pressure value of the explosion-proof notch 300 can be controlled, so that the overall tearing gas pressure value of the explosion-proof notch 300 satisfies the conditions that the explosion-proof notch 300 can be completely torn open, and the tearing force when tearing outward at the opening is reduced, avoiding tearing off the reinforcing belt 200 when the tearing force is too large. In the present embodiment, the second notch 251, the second notch 252, the second notch 253, the second notch 254 and the second notch 255 are arranged on the first curved notch 311, the second notch 256 is arranged at the connection between the first curved notch 311 and the connecting notch 313, the second notch 257, the second notch 258, the second notch 259 and the second notch 260 are arranged on the connecting notch 313, and the second notch 261 is arranged on the second curved notch 312.

[0040] Since the smaller the curvature radius of the curve of the anti-explosion notch 300 is, the more difficult the area is to tear under the same conditions, the curvature radius of each area of the anti-explosion notch 300 can be used to determine whether the area is easy to tear, so as to determine the length of the second notch approximately. In this embodiment, the curvature radius of the first curve notch 311 and the second curve notch 312 is large, and the first curve notch 311 and the second curve notch 312 are not easy to tear, while the curvature radius of the connecting notch 313 is small or is a straight line segment, and the connecting notch 313 is easy to tear. Therefore, when the second notch is set, the maximum length of the second notch overlapping the first curve notch 311 and the second curve notch 312 (i.e. the length of the longest second notch in the area) can be greater than the maximum length of the second notch overlapping the connecting notch 313, so that the area that is not easy to tear is more difficult to tear. Alternatively, the notch residual value of the area where the second notch overlaps the first curve notch 311 and the second curve notch 312 can be less than the notch residual value of the area where the second notch overlaps the connecting notch 313, so that the area that is not easy to tear is more difficult to tear. Of course, the maximum length of the second notch overlapping the first curve notch 311 and the second curve notch 312 can be greater than the maximum length of the second notch overlapping the connecting notch 313, and the notch residual value of the second notch overlapping the first curve notch 311 and the second curve notch 312 can be less than the notch residual value of the second notch overlapping the connecting notch 313.

[0041] In this embodiment, the method for manufacturing the anti-explosion notch 300 is to first perform first laser etching according to the shape and the notch residual value of the first notch 310 to obtain the first notch 310. The etching depth of the first notch 310 obtained by the first laser etching can be 0.05 mm (i.e. the notch residual value is about 0.13 mm) everywhere. Then, second laser etching is performed on the first notch 310 according to the position and the notch residual value of each second notch to form each second notch. The second laser etching is to continue etching downward by 0.05 mm on the basis of the first laser etching, i.e. the total etching depth of each second notch by twice laser etching is about 0.10 mm (i.e. the notch residual value is about 0.08 mm).

[0042] In the embodiment, the reinforcing belt 200 is fixedly arranged outside the explosion-proof score 300, so that the strength of the shell 100 in the area where the reinforcing belt 200 is arranged can be reinforced, to avoid the area from being torn in the explosion process of the explosion-proof score 300, so that the tearing range of the explosion-proof score 300 can be limited by the reinforcing belt 200, to avoid the tearing range of the explosion-proof score 300 from being too large to damage the adjacent battery. The reinforcing belt 200 is designed as a closed belt structure, so that the strength of the shell 100 around the explosion-proof score 300 can be reinforced, to increase the structural strength of the shell 100, avoid the deformation of the shell 100 due to expansion, and ensure the consistency of the opening valve. In addition, the first score 310 adopts the structure that the leading end and the trailing end are inwardly concave, so that a part of the impact force can be converted into inward tearing force when the explosion-proof score 300 is opened, to offset a part of the outward tearing force, and reduce the size of the tearing force when the gap is outwardly torn. The first score 310 is overlapped with a plurality of second scores at intervals to form a shape similar to a dot-dash line, and the tearing difficulty of the small curvature area can be selectively reduced by selecting the position, number, score residual value and length of the second score, so that the tearing difficulties of the areas of the explosion-proof score 300 are close, and the insufficient explosion is avoided.

[0043] The utility model discloses still a kind of secondary batteries, the secondary battery can be power battery or energy storage battery, the shell of the secondary battery can use the battery shell of any one of the above embodiment with reinforced integral explosion-proof valve structure. Of course, the secondary battery also includes the electric core and other conventional secondary batteries necessary structure received in battery shell, these are prior art, and not described here.

[0044] The above embodiments only express the preferred embodiments of the utility model, and the description is more specific and detailed, but it cannot be understood as the limitation of the scope of the utility model patent. It should be pointed out that for ordinary skilled person in the art, without departing from the concept of the utility model, a number of modifications and improvements can be made, which belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent should be subject to the appended claims.

Claims

1. A battery housing having an enhanced integral explosion-proof valve structure, characterized by: The shell is provided with an explosion-proof notch on its outer surface or inner surface, and a reinforcing band is fixed on the outer side of the explosion-proof notch on the outer surface or inner surface of the shell; the explosion-proof notch is a non-closed curve with a gap, thereby forming a tearing area around the gap; the reinforcing band is a linear or curved band structure provided on the outer surface or inner surface of the shell, and the reinforcing band cuts off the tearing area of the explosion-proof notch.

2. The battery case having a reinforced integrated explosion-proof valve structure according to claim 1, characterized in that: The reinforcing band is a closed band structure, and the explosion-proof notch is arranged in the area enclosed by the band structure.

3. The battery case having an enhanced integrated explosion-proof valve structure according to claim 2, characterized in that: The reinforcing band is a circular ring structure, an elliptical ring structure or a ring structure in the shape of a racetrack.

4. The battery case having an enhanced integrated explosion-proof valve structure according to claim 1, wherein: The shell is a rectangular cylindrical structure, including two opposite wide sides and two opposite narrow sides, and the reinforcing band and the explosion-proof notch are arranged on one narrow side.

5. A battery housing having an enhanced integrated explosion relief valve structure according to any one of claims 1 to 4, characterized in that: The explosion-proof notch includes a first notch in the shape of a continuous line; the shape of the first notch is a combination of one or more of a circular arc, an elliptical arc, a spline curve and a straight line segment, and the first end and the tail end of the first notch are not connected.

6. The battery case having a reinforced integrated explosion-proof valve structure according to claim 5, characterized in that: The explosion-proof notch further includes a plurality of second notches arranged along the length direction of the first notch and overlapping thereon, and the second notches have a smaller notch residual value than the first notch.

7. The battery case having a reinforced integrated explosion-proof valve structure according to claim 6, characterized in that: The shell is made of stainless steel with a thickness of 0.15mm-0.3mm, and the reinforcing band is made of stainless steel with a thickness of 0.15mm-0.3mm; the notch residual value at the position where no second notch is arranged on the first notch is 0.10mm-0.15mm; and the notch residual value at the position where a second notch is arranged on the first notch is 0.03mm-0.09mm.

8. The battery case having an enhanced integrated explosion-proof valve structure according to claim 6, wherein: The first notch includes a first curve notch, a second curve notch and a connecting notch, the first end of the connecting notch is connected to the second end of the first curve notch, the second end of the connecting notch is connected to the first end of the second curve notch, and the first end of the first curve notch and the second end of the second curve notch are not connected, thereby forming a gap between the first curve notch and the second curve notch. The first curvature radius threshold is greater than the second curvature radius threshold; the shapes of the first curve notch and the second curve notch are curves with a maximum curvature radius smaller than the second curvature radius threshold, and the shape of the connecting notch is a straight line segment or a curve with a maximum curvature radius greater than the first curvature radius threshold.

9. The battery case having a reinforced integrated explosion-proof valve structure according to claim 8, characterized in that: The shapes of the first curve notch and the second curve notch are circular arcs, elliptical arcs or planar helical lines, and the angles of the first curve notch and the second curve notch are greater than or equal to 180°.

10. A secondary battery characterized by comprising: The battery shell with the enhanced integrated explosion-proof valve structure according to any one of claims 1-9.

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