Shell assembly and battery

Abstract

The invention belongs to the technical field of batteries, and discloses a shell assembly and a battery, the shell assembly is connected with a pole group, the shell assembly comprises a shell body and an anti-explosion valve, the anti-explosion valve comprises a valve opening area, a buffer area, a nick and a welding step, the nick is arranged between the valve opening area and the buffer area, and the welding step is arranged between the valve opening area and the buffer area. The welding step is arranged on the side, away from the nick, of the buffer area, and a mounting hole corresponding to the welding step is formed in the bottom face of the shell body, so that the anti-explosion valve is fixedly connected with the bottom face of the shell body. Thus, the buffer area can disperse stress at the position of the anti-explosion valve, the stress is prevented from being concentrated at the weak position of the anti-explosion valve, the deformation resistance of the anti-explosion valve is improved, the structural strength of the anti-explosion valve is improved, and therefore the anti-explosion valve and the shell body are stably connected, and liquid and gas leakage caused by breakage of the anti-explosion valve is avoided; the explosion-proof valve can have certain deformability, the explosion-proof valve is not prone to being broken due to air pressure fluctuation, and the breathing fatigue resistance of the explosion-proof valve is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a shell assembly and a battery. Background Art

[0002] Lithium-ion batteries, as high-efficiency, high-energy-density energy storage devices, are widely used in electric vehicles, energy storage systems and other fields.

[0003] Existing long-cell lithium-ion batteries include a shell, a cover plate and a battery cell. The battery cell is arranged in a containing space formed by the shell and the cover plate. In order to ensure the safe operation of the long-cell lithium-ion battery, an explosion-proof valve is provided at the bottom of the shell to facilitate timely discharge of gas in the battery and realize thermal and electrical separation to avoid gas accumulation in the shell.

[0004] However, the bottom thickness of the shell of the long-cell lithium-ion battery is smaller than the thickness of the cover. The air pressure inside the shell increases during the exhaust process of the battery cell, which may cause the shell to deform. The difference in stiffness between the thinner shell and the thicker cover will cause stress to concentrate in the explosion-proof valve area, and cause pulling on the explosion-proof valve, resulting in cracks in the notches of the explosion-proof valve and leakage of liquid and air, affecting the normal use of the shell and the explosion-proof valve. The explosion-proof valve has poor anti-deformation ability, anti-leakage performance and anti-respiratory fatigue performance. Summary of the invention

[0005] The object of the present invention is to provide a shell assembly and a battery to solve the problems of poor anti-deformation ability, anti-leakage performance and anti-respiratory fatigue performance of the explosion-proof valve.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, a shell assembly is connected to a pole group, the shell assembly comprising: a shell body; an explosion-proof valve, the explosion-proof valve comprising a valve opening area, a buffer area, a notch and a welding step, the notch being arranged between the valve opening area and the buffer area, the welding step being arranged on a side of the buffer area away from the notch, and a mounting hole corresponding to the welding step being arranged on the bottom surface of the shell body, so that the explosion-proof valve is fixedly connected to the bottom surface of the shell body.

[0008] Preferably, the width of the notch is a and satisfies 0.15 mm ≤ a ≤ 0.3 mm; and / or the thickness of the notch is b and satisfies 0.08 mm ≤ b ≤ 0.18 mm.

[0009] Preferably, the width of the buffer area is c, and satisfies 0.5 mm ≤ c ≤ 2 mm; and / or the width of the welding step is d, and satisfies 1 mm ≤ d ≤ 2.5 mm.

[0010] Preferably, the width of the notch from the outer edge of the explosion-proof valve is e, and satisfies 1.5mm≤e≤4.5mm; and / or the thickness of the buffer area is f, and satisfies 0.2mm≤f≤0.4mm.

[0011] Preferably, the thickness of the notch is b, the thickness of the buffer area is f, and they satisfy 20%≤b / f≤90%; and / or, the width of the notch is a, the width of the buffer area is c, and they satisfy 7.5%≤a / c≤60%.

[0012] Preferably, the shell body is connected with a protrusion, the protrusion is protrudingly arranged on the bottom surface of the shell body, the protrusion extends in a direction away from the pole group, and the mounting hole is opened in the protrusion.

[0013] Preferably, the shell body is connected with a lap step, and the lap step is arranged in the mounting hole for supporting the explosion-proof valve.

[0014] Preferably, the welding step is arranged on a side of the mounting hole facing the pole group, or the welding step is located inside the mounting hole.

[0015] Preferably, the thickness of the wall of the shell body on which the explosion-proof valve is arranged is greater than the thickness of other walls of the shell body.

[0016] In a second aspect, a battery comprises a pole group, a cover plate and the shell assembly as described above, wherein the cover plate is connected to the shell body, and the pole group is arranged inside the shell body.

[0017] Beneficial effects of the present invention:

[0018] A shell component is connected to a pole group. The shell component includes a shell body and an explosion-proof valve. The explosion-proof valve includes a valve opening area, a buffer area, a notch and a welding step. The notch is arranged between the valve opening area and the buffer area. The welding step is arranged on the side of the buffer area away from the notch. The bottom surface of the shell body is provided with a mounting hole corresponding to the welding step, so that the explosion-proof valve is fixedly connected to the bottom surface of the shell body.

[0019] In this way, when the battery cell is producing gas during charge and discharge cycles, the buffer area can disperse the stress on the explosion-proof valve, avoid stress concentration on the weak points of the explosion-proof valve, reduce deformation and rupture of the explosion-proof valve under pressure fluctuations, improve the explosion-proof valve's resistance to breathing fatigue, and extend the service life of the explosion-proof valve. The explosion-proof valve is connected to the shell body through a welding step, which can improve the sealing and stability of the connection between the explosion-proof valve and the shell body, thereby improving the explosion-proof valve's anti-leakage performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1It is a side view of the housing assembly in the first embodiment of the present invention;

[0021] Figure 2 It is a side view of the explosion-proof valve in the first embodiment of the present invention;

[0022] Figure 3 It is a partial side sectional view of the explosion-proof valve in the first embodiment of the present invention;

[0023] Figure 4 It is a top view of the explosion-proof valve in the first embodiment of the present invention;

[0024] Figure 5 It is a structural schematic diagram of the explosion-proof valve in the first embodiment of the present invention;

[0025] Figure 6 It is a side view of the housing assembly in the second embodiment of the present invention;

[0026] Figure 7 It is a side view of the housing assembly in the third embodiment of the present invention;

[0027] Figure 8 It is a first structural schematic diagram of the housing assembly in the third embodiment of the present invention;

[0028] Figure 9 It is a bottom view of the housing assembly in the third embodiment of the present invention;

[0029] Figure 10 It is a second structural schematic diagram of the housing assembly in the third embodiment of the present invention.

[0030] In the figure:

[0031] 1. Housing body; 11. Mounting hole; 12. Protruding part; 13. Lapping step; 2. Explosion-proof valve; 21. Valve opening area; 22. Buffer area; 23. Scratch; 24. Welding step. Detailed implementation manners

[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. In addition, it should be noted that for the sake 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 specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in 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] Embodiment 1

[0037] See also Figure 1 and Figure 2 The present invention provides a shell assembly connected to a pole group (not shown in the figure), the shell assembly includes a shell body 1 and an explosion-proof valve 2, the explosion-proof valve 2 includes a valve opening area 21, a buffer area 22, a notch 23 and a welding step 24, the notch 23 is arranged between the valve opening area 21 and the buffer area 22, the welding step 24 is arranged on the side of the buffer area 22 away from the notch 23, and the bottom surface of the shell body 1 is provided with a mounting hole 11 corresponding to the welding step 24, so that the explosion-proof valve 2 is fixedly connected to the bottom surface of the shell body 1.

[0038] In this embodiment, the explosion-proof valve 2 has a kidney-shaped plate structure. The valve-opening area 21 is arranged at the center of the explosion-proof valve 2. The notch 23 is arranged around the outer edge of the valve-opening area 21. The buffer area 22 is arranged between the welding step 24 and the notch 23 and around the notch 23 to disperse the stress on the explosion-proof valve 2. The surface of the welding step 24 facing away from the electrode group is flush with the surface of the valve-opening area 21 facing away from the electrode group. The explosion-proof valve 2 is fixedly connected to the bottom surface of the housing body 1 by welding. The thicknesses of the top surface, bottom surface, and side surface of the housing body 1 are equal.

[0039] In this way, when the internal pressure of the housing body 1 is too high, the notch 23 cracks under the gas pressure, opening the valve-opening area 21, enabling the gas inside the battery to be quickly discharged to the outside. The buffer area 22 can disperse the stress on the explosion-proof valve 2, preventing stress concentration at the weak point of the explosion-proof valve 2 (i.e., the position where the notch 23 is opened) when the bottom surface of the housing deforms, improving the anti-deformation ability of the explosion-proof valve 2, preventing the explosion-proof valve 2 from being pulled and broken by the bottom surface of the housing body 1, improving the anti-leakage performance of the explosion-proof valve 2, and being able to improve the anti-breathing fatigue performance of the explosion-proof valve 2 when the air pressure changes; the welding step 24 can provide a welding space at the connection between the explosion-proof valve 2 and the housing body 1, enabling the explosion-proof valve 2 to be stably connected to the housing body 1, and improving the stability and sealing performance at the connection between the explosion-proof valve 2 and the housing body 1.

[0040] It can be understood that the shape of the explosion-proof valve 2 and the arrangement positions of the valve-opening area 21, buffer area 22, notch 23, and welding step 24 of the explosion-proof valve 2 can be adjusted according to actual design requirements and will not be elaborated here.

[0041] Refer to Figures 3 to 5 , in some embodiments, the width of the notch 23 is a, and 0.15 mm ≤ a ≤ 0.3 mm is satisfied. The thickness of the notch 23 is b, and 0.08 mm ≤ b ≤ 0.18 mm is satisfied.

[0042] In this embodiment, the width a of the notch 23 can be any value between 0.15 mm and 0.3 mm or the range between any two values, such as 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc. The thickness b of the notch 23 can be any value between 0.08 mm and 0.18 mm or the range between any two values, such as 0.08 mm, 0.1 mm, 0.15 mm, 0.18 mm, etc.

[0043] Thus, the notch 23 has sufficient width and thickness, which can not only guide the stress distribution during gas discharge to ensure that the notch 23 can deform preferentially when the internal air pressure of the housing increases, but also avoid excessive deformation or fracture, improve the anti-deformation ability of the explosion-proof valve 2, enable the explosion-proof valve 2 to discharge gas stably, reduce the fatigue damage of the explosion-proof valve 2 caused by excessive deformation during air pressure change, further improve the anti-breathing fatigue performance of the explosion-proof valve 2, extend the service life of the explosion-proof valve 2, and improve the connection stability between the valve opening area 21 and the buffer area 22.

[0044] It can be understood that the width a of the notch 23 cannot be too large, otherwise the stress dispersion effect around the notch 23 will be weakened, the stress concentration area will be enlarged, resulting in local deformation or rupture of the explosion-proof valve 2 during air pressure change, and the structural strength at the notch 23 will be reduced, increasing the risk of liquid leakage and air leakage. The width a of the notch 23 cannot be too small either, otherwise the stress will be overly concentrated at the notch 23, affecting the sensitivity of the explosion-proof valve 2. A notch 23 with a too narrow width requires a high processing precision and it is difficult to ensure the uniformity of the notch 23.

[0045] Furthermore, the thickness b of the notch 23 cannot be too large, otherwise it will affect the bursting force of the explosion-proof valve 2, making it difficult for the notch 23 to rupture when the internal air pressure of the housing is too large, reducing the sensitivity of the explosion-proof valve 2 to air pressure change. The thickness b of the notch 23 cannot be too small either, otherwise the structural strength at the location where the notch 23 is opened on the explosion-proof valve 2 will be reduced, increasing the risk of liquid leakage and air leakage. Therefore, both the width a and the thickness b of the notch 23 can be adjusted according to actual needs and will not be listed in detail here.

[0046] Refer to Figure 3 and Figure 4 , in some embodiments, the width of the buffer area 22 is c, and 0.5 mm ≤ c ≤ 2 mm is satisfied; the width of the welding step 24 is d, and 1 mm ≤ d ≤ 2.5 mm is satisfied.

[0047] In this embodiment, the width c of the buffer area 22 can be any value between 0.5 mm and 2 mm or the range between any two values, such as 0.5 mm, 1 mm, 1.5 mm, 2 mm, etc.; the width d of the welding step 24 can be any value between 1 mm and 2.5 mm or the range between any two values, such as 1 mm, 1.5 mm, 2 mm, 2.5 mm, etc.

[0048] In this way, the buffer region 22 can achieve stress buffering and dispersion, avoiding stress concentration and the notch 23 area. When there is air pressure fluctuation inside the housing body 1, the explosion-proof valve 2 has good anti-deformation ability and anti-breathing fatigue performance, and keeps good sealing performance between the explosion-proof valve 2 and the bottom surface of the housing body 1. The welding step 24 can provide sufficient welding space between the explosion-proof valve 2 and the housing body 1, enabling the explosion-proof valve 2 and the housing body 1 to be hermetically and fixedly connected, reducing the risk of liquid leakage and air leakage, and avoiding stress concentration at the connection between the welding step 24 and the housing body 1.

[0049] It can be understood that the width c of the buffer region 22 cannot be too large. If it is too large, the overall size of the explosion-proof valve 2 will increase, increasing the processing difficulty. And an overly wide buffer region 22 may cause uneven stress dispersion. When the air pressure inside the housing body 1 is too large, it will delay the rupture speed of the notch 23 and reduce the battery exhaust efficiency. The width c of the buffer region 22 cannot be too small either. If it is too small, the buffering effect will deteriorate, making it difficult to disperse stress, resulting in stress concentration at the notch 23 and reducing the anti-deformation ability of the explosion-proof valve 2. The width d of the welding step 24 cannot be too large. If it is too large, the size of the explosion-proof valve 2 will be too large, and stress will concentrate at the connection between the housing body 1 and the welding step 24, reducing the connection strength. The width d of the welding step 24 cannot be too small either. If it is too small, the overlapping area between the welding step 24 and the housing body 1 will be too small, without enough space for welding, resulting in defects such as low welding strength and poor welding quality, affecting the sealing performance of the explosion-proof valve 2.

[0050] Refer to Figure 3 and Figure 4 In some embodiments, the width of the notch 23 from the outer edge of the explosion-proof valve 2 is e, and it satisfies 1.5 mm ≤ e ≤ 4.5 mm. The thickness of the buffer region 22 is f, and it satisfies 0.2 mm ≤ f ≤ 0.4 mm.

[0051] In this embodiment, the width e of the notch 23 from the outer edge of the explosion-proof valve 2 can be any value between 1.5 mm and 4.5 mm or the range between any two values, such as 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, etc. The thickness f of the buffer region 22 can be any value between 0.2 mm and 0.4 mm or the range between any two values, such as 0.2 mm, 0.3 mm, 0.4 mm, etc.

[0052] In this way, a distance can be left between the notch 23 and the outer edge of the explosion-proof valve 2 (i.e., the outer edge of the welding step 24), preventing the deformation of the notch 23 from being driven and cracked when the housing body 1 deforms, improving the liquid leakage prevention performance of the explosion-proof valve 2, enabling the buffer area 22 to effectively disperse stress, enhancing the anti-deformation ability and structural stability of the explosion-proof valve 2, realizing a sealed and fixed connection between the explosion-proof valve 2 and the housing body 1, absorbing part of the deformation caused by the gas production of the battery cell through the buffer area 22, and improving the anti-breathing fatigue performance of the explosion-proof valve 2; by defining the thickness f of the buffer area 22, the buffer area 22 can have a certain structural strength, preventing the buffer area 22 from being too weak.

[0053] It can be understood that the width e of the notch 23 from the outer edge of the explosion-proof valve 2 should not be too large, otherwise the overall size of the explosion-proof valve 2 will be too large, and the sensitivity of the explosion-proof valve 2 will be reduced, which is not conducive to the timely opening and exhaust of the valve opening area 21. The width e of the notch 23 from the outer edge of the explosion-proof valve 2 should not be too small either, otherwise stress will concentrate at the connection between the explosion-proof valve 2 and the housing body 1 and at the notch 23, and the structural strength at the notch 23 of the explosion-proof valve 2 is relatively low, increasing the risk of liquid leakage and air leakage. The thickness f of the buffer area 22 should not be too large, otherwise the overall thickness of the explosion-proof valve 2 will increase and the occupied area will also increase. The thickness f of the buffer area 22 should not be too small either, otherwise the structural strength of the buffer area 22 will be insufficient, reducing the stress dispersion effect. The width e of the notch 23 from the outer edge of the explosion-proof valve 2 and the thickness f of the buffer area 22 can be flexibly adjusted according to actual needs, and will not be listed in detail here.

[0054] Refer to Figure 3 and Figure 4 In some embodiments, 20% ≤ b / f ≤ 90%, 7.5% ≤ a / c ≤ 60%.

[0055] In this embodiment, the ratio of the thickness b of the notch 23 to the thickness f of the buffer area 22 can be any value between 20% and 90% or the range between any two values, such as 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, etc. The ratio of the width a of the notch 23 to the width c of the buffer area 22 can be any value between 7.5% and 60% or the range between any two values, such as 7.5%, 10%, 20%, 30%, 40%, 50%, 60%, etc.

[0056] Thus, by defining the ratio of the thickness b of the notch 23 to the thickness f of the buffer region 22 and the ratio of the width a of the notch 23 to the width c of the buffer region 22, the notch 23 can maintain structural stability before the air pressure reaches the bursting value, preventing the notch 23 from cracking. Moreover, the buffer region 22 can disperse the stress on the explosion-proof valve 2, avoiding stress concentration at the notch 23, reducing deformation and cracking of the explosion-proof valve 2 under air pressure fluctuations, improving the sealing performance and stability at the connection between the explosion-proof valve 2 and the housing body 1, and enhancing the liquid leakage prevention performance of the explosion-proof valve 2.

[0057] It can be understood that the ratio of the thickness b of the notch 23 to the thickness f of the buffer region 22 cannot be too small, otherwise the remaining thickness of the notch 23 will be too thin and prone to cracking, reducing safety; the ratio of the thickness b of the notch 23 to the thickness f of the buffer region 22 cannot be too large either, otherwise the remaining thickness of the notch 23 will be too large, making it difficult to effectively open when the battery cell undergoes thermal runaway. The ratio of the width a of the notch 23 to the width c of the buffer region 22 cannot be too small, otherwise the strain dispersion effect of the buffer region 22 will weaken and the notch 23 is prone to cracking. The ratio of the width a of the notch 23 to the width c of the buffer region 22 cannot be too large either, otherwise it will affect the opening of the explosion-proof valve 2 when the battery cell undergoes thermal runaway.

[0058] Refer to Figure 1 , in some embodiments, the housing body 1 is connected with a protruding portion 12. The protruding portion 12 protrudes from the bottom surface of the housing body 1 and extends in a direction away from the electrode group. The mounting hole 11 is formed in the protruding portion 12.

[0059] In this embodiment, the protruding portion 12 and the housing body 1 are integrally formed, and the protruding height of the protruding portion 12 is not less than the thickness of the explosion-proof valve 2 (i.e., the thickness of the welding step 24), so that the surface of the explosion-proof valve 2 facing away from the protruding portion does not exceed the surface of the housing body 1 facing the electrode group.

[0060] Thus, the explosion-proof valve 2 is disposed within the protruding portion 12 and does not protrude from the housing body 1, which can prevent the explosion-proof valve 2 from interfering with other structures inside the housing body 1, enabling the explosion-proof valve 2 to be stably connected to the housing body 1. The protruding portion 12 increases the thickness of the bottom surface of the housing body 1, thereby increasing the structural strength of the bottom surface of the housing body 1 and improving the anti-deformation ability of the bottom surface of the housing body 1, preventing the bottom surface of the housing body 1 from driving the explosion-proof valve 2 to deform during the charge and discharge cycle of the battery cell.

[0061] It can be understood that the height and the setting position of the protruding portion 12 can be adjusted according to the actual design and will not be elaborated here. In this embodiment, in order to make the structural strength of the bottom surface of the housing body 1 uniform, the protruding portion 12 is disposed at the center position of the bottom surface of the housing body 1.

[0062] Refer to Figure 1, in some embodiments, the welding step 24 is provided on the side of the mounting hole 11 facing the electrode group.

[0063] In this embodiment, the explosion-proof valve 2 is provided on the side of the protruding portion 12 facing the electrode group. Along the thickness direction of the explosion-proof valve 2, the projection of the notch 23 is located inside the projection of the mounting hole 11, so that the valve-opening area 21 can be opened smoothly.

[0064] In this way, setting the explosion-proof valve 2 inside the protruding portion 12 can not only make reasonable use of the internal space of the housing body 1, but also guide the gas to be discharged to the outside through the explosion-proof valve 2, and improve the connection strength between the welding step 24 and the protruding portion 12, so that the explosion-proof valve 2 can evenly distribute stress when the air pressure changes, reduce the deformation and rupture at the notch 23 under the action of the buffer area 22, improve the anti-deformation ability and anti-breathing fatigue performance of the explosion-proof valve 2. The protruding portion 12 can also provide protection for the welding step 24, reduce the impact of the outside on the welding step 24, and improve the sealing performance at the connection between the explosion-proof valve 2 and the housing body 1.

[0065] Refer to Figure 1 , the present invention also provides a battery, including an electrode group, a cover plate and a housing assembly. The cover plate is connected to the housing body 1, and the electrode group is arranged inside the housing body 1.

[0066] In this embodiment, the housing body 1 and the cover plate enclose a sealed space for accommodating the electrode group to protect the electrode group.

[0067] Embodiment Two

[0068] For the same or corresponding components in Embodiment Two and Embodiment One, the corresponding reference numerals in Embodiment One are used. For the sake of simplicity, only the differences between Embodiment Two and Embodiment One are described.

[0069] Refer to Figure 6 , in some embodiments, the wall thickness of the housing body 1 where the explosion-proof valve 2 is provided is greater than the thickness of other walls of the housing body 1. That is, the thickness of the bottom surface of the housing body 1 is greater than the thickness of the side surface and the top surface of the housing body 1.

[0070] In this way, the bottom surface of the housing body 1 can have sufficient structural strength to support the explosion-proof valve 2 and the electrode group, so that a sealed connection can be achieved at the connection between the explosion-proof valve 2 and the bottom surface of the housing body 1, avoiding liquid leakage and air leakage, improving the structural strength of the bottom surface of the housing body 1 and the connection strength at the connection between the housing body 1 and the explosion-proof valve 2, avoiding the deformation of the bottom surface of the housing body 1 due to air pressure changes, improving the anti-deformation ability of the housing body 1 and the explosion-proof valve 2, and enabling the bottom surface of the housing body 1 to distribute stress more evenly, improving the anti-breathing fatigue performance of the explosion-proof valve 2.

[0071] It can be understood that the wall thickness of the housing body 1 where the explosion-proof valve 2 is provided can be adjusted according to actual needs, and no more examples are listed here.

[0072] Refer to Figure 6 , in some embodiments, the housing body 1 is connected with a lapping step 13, and the lapping step 13 is arranged in the mounting hole 11 for supporting the explosion-proof valve 2.

[0073] Furthermore, in some embodiments, the welding step 23 is located inside the mounting hole 11, and the surface of the welding step 23 is flush with the surface of the protruding part 12.

[0074] In this embodiment, the cross-sectional area of the mounting hole 11 towards the pole group is smaller than the cross-sectional area of its end away from the pole group. The surface of the welding step 24 towards the pole group abuts against the surface of the lapping step 13 away from the pole group. And the mounting hole 11 penetrates through the protruding part 12. The inner wall of the mounting hole 11 of the side wall of the welding step 24 abuts against the protruding part 12, so that when the welding step 24 is connected with the lapping step 13, the surface of the welding step 24 away from the pole group is flush with the surface of the protruding part 12.

[0075] Thus, by setting the lapping step 13, stable support can be provided for the explosion-proof valve 2, so that the explosion-proof valve 2 is stably connected to the bottom surface of the housing body 1 through the protruding part 12 and the lapping step 13 respectively. And the mounting hole 11 can limit the welding step 24 to avoid deformation or displacement of the explosion-proof valve 2 when it is assembled to the bottom surface of the housing body 1, and evenly disperse the stress to improve the anti-deformation ability of the explosion-proof valve 2; after the explosion-proof valve 2 is assembled to the housing body 1, the surface of the welding step 24 away from the pole group is flush with the surface of the protruding part 12 away from the pole group, which can make the bottom surface of the housing body 1 flatter. And the valve opening area 21 and the notch 23 are recessed in the welding step 24, which can reduce the interference of the external structure on the explosion-proof valve 2, avoid leakage of liquid or gas caused by impact at the notch 23, and improve the anti-breathing fatigue performance.

[0076] Refer to Figure 6 , in some embodiments, the surface of the lapping step 13 towards the pole group is flush with the end surface of the mounting hole 11 towards the pole group. That is to say, the lapping step 13 is arranged at one end of the mounting hole 11 towards the pole group.

[0077] Thus, the lapping step 13 can provide stable support for the explosion-proof valve 2, evenly disperse the stress, improve the anti-deformation ability of the explosion-proof valve 2, enable the wall thickness of the bottom surface of the housing body 1 to be effectively utilized by the explosion-proof valve 2 and the lapping step 13, improve the stability of the connection between the explosion-proof valve 2 and the housing body 1, avoid the risk of liquid or gas leakage caused by loose connection, and improve the anti-breathing fatigue performance of the explosion-proof valve 2; by connecting the welding step 24 with the lapping step 13, preliminary positioning of the explosion-proof valve 2 can be carried out, which is convenient for subsequent assembly.

[0078] It can be understood that the setting position of the lapping step 13 can be adjusted according to actual needs and will not be elaborated here.

[0079] Example 3

[0080] For the same or corresponding components in Example 3 and Example 1, the corresponding reference numerals in Example 1 are used. For simplicity, only the differences between Example 3 and Example 1 are described.

[0081] Refer to Figures 7 to 10 , in some embodiments, the bottom surface of the housing body 1 is flush, that is, there is no raised portion on the bottom surface of the housing body 1, the mounting hole 11 is a through hole penetrating the bottom surface of the housing body 1, and the overlapping step 13 is provided at one end of the mounting hole 11 facing the electrode group.

[0082] In this way, the bottom surface of the housing body 1 after assembling the explosion-proof valve 2 can be made flatter, the overall structural strength of the housing assembly can be made more stable, the anti-deformation ability of the housing assembly can be improved. Under the limiting action of the overlapping step 13 and the mounting hole 11, the explosion-proof valve 2 is not likely to be displaced or fall off, and can maintain a sealed connection with the bottom surface of the housing body 1, improving the anti-leakage performance, and can reduce the deformation under air pressure fluctuations, improving the anti-breathing fatigue performance.

[0083] Further, the structure of the housing body 1 in Example 1 is A, the structure of the housing body 1 in Example 2 is B, and the structure of the housing body 1 in Example 3 is C. For different types of housing body 1 structures, their influence degrees on the breathing fatigue of the explosion-proof valve 2 are different, specifically A ≤ B ≤ C, that is, A has the smallest influence degree on the breathing fatigue of the explosion-proof valve 2, and C has the largest influence degree on the breathing fatigue of the explosion-proof valve 2; and, the breathing fatigue strain coefficient of the explosion-proof valve 2 assembled on the A structure is 1, the breathing fatigue strain coefficient of the explosion-proof valve 2 assembled on the B structure is 1.2, and the breathing fatigue strain coefficient of the explosion-proof valve 2 assembled on the C structure is 1.5.

[0084] In order to verify the rationality of the width a of the notch 23, the thickness b of the notch 23, the width e of the notch 23 from the outer edge of the explosion-proof valve 2, and the housing structure, as shown in Table 1, this embodiment provides nine groups of examples and six groups of comparative examples for illustration.

[0085] Table 1

[0086]

[0087] It can be seen from Examples 1 to 9 in Table 1 that after meeting the range limitation, the explosion-proof valve 2 has good anti-breathing fatigue performance, and the strain of the explosion-proof valve 2 is less than the strain threshold, having good anti-deformation ability.

[0088] It can be seen from Comparative Example 1 in Table 1 that when the width a of the notch 23 is too small, the structural strength at the notch 23 is low, and there are risks of cracking and leakage of liquid and gas.

[0089] As can be seen from Comparative Example 2 in Table 1, when the width a of the notch 23 is too large, it is difficult to achieve production and processing, resulting in a low production yield of the explosion-proof valve 2, which is not conducive to mass production.

[0090] As can be seen from Comparative Example 3 in Table 1, when the thickness b of the notch 23 is too small, the structural strength at the notch 23 is low, and there are risks of cracking and leakage of liquid and gas.

[0091] As can be seen from Comparative Example 4 in Table 1, when the thickness b of the notch 23 is too large, although the strain threshold can be passed, the excessive remaining thickness of the notch 23 will result in a high bursting value of the explosion-proof valve 2, reducing the sensitivity of the explosion-proof valve 2. The bursting value of the explosion-proof valve 2 is close to the bursting value of the housing body 1, making it difficult to discharge gas in a timely manner.

[0092] As can be seen from Comparative Example 5 in Table 1, when the width e of the notch 23 from the outer edge of the explosion-proof valve 2 is too small, it will not only lead to low structural strength of the explosion-proof valve 2, resulting in risks of cracking and leakage of liquid and gas for the explosion-proof valve 2, but also the fact that the notch 23 of the explosion-proof valve 2 is too close to the edge of the explosion-proof valve 2 will cause stress deformation of the notch 23 during welding, and a too small welding platform will lead to difficult welding and a low welding yield, which is not conducive to the mass production of the explosion-proof valve 2.

[0093] As can be seen from Comparative Example 6 in Table 1, when the width e of the notch 23 from the outer edge of the explosion-proof valve 2 is too large, if the overall size of the explosion-proof valve 2 remains unchanged, the non-opening valve area (i.e., the buffer area 22, the notch 23, and the welding step 24) is large, making the area of the opening valve area 21 small, resulting in space waste. If the area of the opening valve area 21 is made large enough, the overall area of the explosion-proof valve 2 will increase, occupying more space on the bottom surface of the housing body 1, which is not conducive to production and assembly.

[0094] To verify the rationality of the ranges of the thickness b of the notch 23, the thickness f of the buffer area 22, the width a of the notch 23, and the width c of the buffer area 22, as shown in Table 2, this embodiment provides ten groups of examples and eight groups of comparative examples.

[0095] Table 2

[0096]

[0097] As can be seen from Examples 1 to 10 in Table 2, after meeting the range limitations, the ratio of the thickness b of the notch 23 to the thickness f of the buffer area 22 and the ratio of the width a of the notch 23 to the width c of the buffer area 22 are reasonable, without the risk of breakage and cracking and meeting the safety requirements of the battery cell. The valve opens normally when the battery cell undergoes thermal runaway.

[0098] As can be seen from Comparative Example 1 and Comparative Example 2 in Table 2, the ratio of the thickness b of the notch 23 to the thickness f of the buffer area 22 is too large, resulting in an excessive remaining thickness of the notch 23. The explosion-proof valve cannot be effectively opened when the battery cell undergoes thermal runaway, and the safety of the battery cell cannot be guaranteed.

[0099] As can be seen from Comparative Example 3 and Comparative Example 4 in Table 2, the ratio of the thickness b of the notch 23 to the thickness f of the buffer region 22 is too small, and the remaining thickness is too thin, resulting in easy cracking of the battery cell under conditions such as vibration and extrusion, and the safety of the battery cell cannot be guaranteed.

[0100] As can be seen from Comparative Example 5 and Comparative Example 6 in Table 2, the ratio of the width a of the notch 23 to the width c of the buffer region 22 is too large. When the battery cell is in thermal runaway, the explosion-proof valve 2 cannot be effectively opened, and the safety of the battery cell cannot be guaranteed.

[0101] As can be seen from Comparative Example 7 and Comparative Example 8 in Table 2, the ratio of the width a of the notch 23 to the width c of the buffer region 22 is too small, the strain buffering effect is reduced, the notch 23 is prone to cracking, and there is a risk of liquid leakage in the battery cell.

[0102] Obviously, the above-mentioned embodiments of the present invention are only examples for clearly explaining the present invention, and are not intended to limit 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 the implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A housing assembly, characterized in that: Connected to the pole group, the shell assembly includes: Shell body (1); An explosion-proof valve (2), the explosion-proof valve (2) comprising a valve opening area (21), a buffer area (22), a notch (23) and a welding step (24), the notch (23) being arranged between the valve opening area (21) and the buffer area (22), the welding step (24) being arranged on a side of the buffer area (22) away from the notch (23), and a mounting hole (11) corresponding to the welding step (24) being arranged on the bottom surface of the shell body (1), so that the explosion-proof valve (2) is fixedly connected to the bottom surface of the shell body (1).

2. The housing assembly according to claim 1, characterized in that: The width of the notch (23) is a and satisfies 0.15 mm ≤ a ≤ 0.3 mm; and / or the thickness of the notch (23) is b and satisfies 0.08 mm ≤ b ≤ 0.18 mm.

3. The housing assembly according to claim 1, characterized in that: The width of the buffer area (22) is c, and satisfies 0.5 mm ≤ c ≤ 2 mm; and / or the width of the welding step (24) is d, and satisfies 1 mm ≤ d ≤ 2.5 mm.

4. The housing assembly according to claim 1, characterized in that: The width of the notch (23) from the outer edge of the explosion-proof valve (2) is e, and satisfies 1.5mm≤e≤4.5mm; and / or the thickness of the buffer area (22) is f, and satisfies 0.2mm≤f≤0.4mm.

5. The housing assembly according to claim 1, characterized in that: The thickness of the notch (23) is b, the thickness of the buffer region (22) is f, and they satisfy 20%≤b / f≤90%; and / or the width of the notch (23) is a, the width of the buffer region (22) is c, and they satisfy 7.5%≤a / c≤60%.

6. The housing assembly according to any one of claims 1 to 5, characterized in that: The shell body (1) is connected to a protruding portion (12), the protruding portion (12) is protruding from the bottom surface of the shell body (1), the protruding portion (12) extends in a direction away from the pole group, and the mounting hole (11) is opened in the protruding portion (12).

7. The housing assembly according to any one of claims 1 to 5, characterized in that: The housing body (1) is connected to a lap step (13), and the lap step (13) is arranged in the mounting hole (11) and is used to support the explosion-proof valve (2).

8. The housing assembly according to any one of claims 1 to 5, characterized in that: The welding step (24) is arranged on a side of the mounting hole (11) facing the pole group, or the welding step (24) is located inside the mounting hole (11).

9. The housing assembly according to any one of claims 1 to 5, characterized in that: The thickness of the wall of the shell body (1) on which the explosion-proof valve (2) is arranged is greater than the thickness of other walls of the shell body (1).

10. A battery, characterized in that: It comprises a pole group, a cover plate and a shell assembly as claimed in any one of claims 1 to 9, wherein the cover plate is connected to the shell body (1), and the pole group is arranged inside the shell body (1).

Images