Shell structure, battery monomer, battery module and battery pack

Abstract

The invention belongs to the technical field of batteries, and discloses a shell structure, a battery monomer, a battery module and a battery pack, the shell structure comprises a first wall body, two second wall bodies and two buffer walls, the first wall body is provided with an anti-explosion valve, the thickness of the first wall body is T1, the two second wall bodies are respectively located on two opposite sides of the first wall body, and the two buffer walls are arranged on the first wall body. The thickness of each second wall body is T2, the two second wall bodies are connected with the first wall body through the corresponding buffer walls respectively, the thickness of each buffer wall is T3, T2 + T3 is smaller than or equal to T1, and the shell structure can reduce the probability that the explosion-proof valve is exploded in advance to be opened.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and particularly to a housing structure, a battery cell, a battery module, and a battery pack. Background Art

[0002] The housing of a square battery generally includes a large housing surface and a small housing surface. As Figure 1 shown, the prior art proposes a solution in which an explosion-proof hole 11' is opened on the small housing surface 1', and an explosion-proof valve 2' is welded and sealed at the explosion-proof hole 11'. When the pressure in the housing rises to the bursting value during battery thermal runaway, the explosion-proof valve 2' bursts open to discharge the high-pressure gas in the housing, ensuring the safe use of the battery.

[0003] In actual production, the thickness of the battery housing is minimized as much as possible to increase the energy density of the battery, but this will greatly reduce the structural strength of the battery housing. When the battery expands and when the battery is externally squeezed, the large housing surface 3' will expand outward and dent inward, and when the large housing surface 3' deforms, it will pull and squeeze the small housing surface 1', causing the explosion-proof valve 2' to be subjected to corresponding pulling and squeezing forces. This reciprocating force is likely to cause the problem of creep fatigue of the explosion-proof valve 2', and further cause the explosion-proof valve 2' to burst open in advance when the pressure in the housing does not reach the bursting value.

[0004] Therefore, there is an urgent need to propose a housing structure, a battery cell, a battery module, and a battery pack to solve the above technical problems. Summary of the Invention

[0005] The first object of the present invention is to provide a housing structure that can reduce the probability of the explosion-proof valve bursting open in advance.

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

[0007] A housing structure, comprising:

[0008] A first wall body, on which an explosion-proof valve is provided, and the thickness of the first wall body is T1;

[0009] Two second wall bodies, which are respectively located on opposite sides of the first wall body, and the thickness of the second wall body is T2;

[0010] Two buffer walls, each of the two second wall bodies is connected to the first wall body through a corresponding buffer wall, the thickness of the buffer wall is T3, and T2 + T3 ≤ T1.

[0011] Optionally, the buffer wall is a rounded corner wall.

[0012] Optionally, the inner surface of the rounded corner wall and the inner surface of the first wall body are connected by a transition surface, the transition surface is a smooth curved surface, one side of the transition surface is tangent to the inner surface of the rounded corner wall, and the other side of the transition surface is tangent to the inner surface of the first wall body.

[0013] Optionally, the distance between the position where the transition surface is tangent to the inner surface of the first wall body and the inner surface of the second wall body is L, and L / T2≥4.

[0014] Optionally, T2≥0.5mm.

[0015] Optionally, T1≥1mm.

[0016] Optionally, T3≥0.4mm.

[0017] The second object of the present invention is to provide a battery cell, and the probability of the early explosion and valve opening problem of the explosion-proof valve of the battery cell is relatively low.

[0018] To achieve this purpose, the present invention adopts the following technical solutions:

[0019] A battery cell, comprising a pole group and the above-mentioned housing structure, the housing structure is provided with a receiving cavity, and the pole group is arranged in the receiving cavity.

[0020] The third object of the present invention is to provide a battery module, and the use safety of the battery module is relatively high.

[0021] To achieve this purpose, the present invention adopts the following technical solutions:

[0022] A battery module, comprising the above-mentioned battery cell.

[0023] The fourth object of the present invention is to provide a battery pack, and the use safety of the battery pack is relatively high.

[0024] To achieve this purpose, the present invention adopts the following technical solutions:

[0025] A battery pack, comprising the above-mentioned battery module.

[0026] The beneficial effects of the present invention:

[0027] For the housing structure provided by the present invention, the two second wall bodies are respectively connected to the first wall body through a corresponding buffer wall. When the second wall body expands or is extruded by an external force, the second wall body transmits the pulling or extrusion force to the buffer wall. Since T2+T3≤T1, the thickness of the buffer wall is less than the thickness of the first wall body. Furthermore, the structural strength of the buffer wall is less than the structural strength of the first wall body. When the buffer wall receives the force transmitted by the second wall body, the buffer wall deforms. Thus, the influence on the first wall body caused by the expansion of the second wall body or the extrusion by an external force can be greatly reduced, and further the probability of the early explosion and valve opening problem of the explosion-proof valve can be reduced. Brief Description of the Drawings

[0028] Figure 1 is a schematic structural view of a housing in the prior art;

[0029] Figure 2 is a schematic view of the housing structure provided by the present invention;

[0030] Figure 3 is Figure 2 a partial enlarged view at A in

[0031] Figure 4 is a partial enlarged view of the housing structure provided by the present invention;

[0032] Figure 5 is Figure 4 a partial enlarged view at B in

[0033] Figure 6 is a schematic assembly view of multiple housing structures provided by the present invention;

[0034] Figure 7 is a schematic structural view of a battery cell provided by the present invention.

[0035] In the figure:

[0036] 1', small surface of the housing; 11', explosion-proof hole; 2', explosion-proof valve; 3', large surface of the housing;

[0037] 1, the first wall body; 11, explosion-proof valve; 12, explosion-proof hole; 2, the second wall body; 3, buffer wall; 31, rounded corner wall; 4, transition surface; 41, transition area; 5, the third wall body; 6, accommodation cavity; 7, housing structure; 8, cover plate. Detailed Description of the Invention

[0038] The present invention will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the convenience of description, only parts related to the present invention are shown in the drawings, rather than all the structures.

[0039] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] In the present invention, unless otherwise clearly specified or limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0041] In the description of this embodiment, the orientation or positional relationships such as "above", "below", "right", etc. are based on the orientation or positional relationships shown in the drawings. They are only for the convenience of description and simplifying the operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for distinction in description and have no special meaning.

[0042] This embodiment provides a housing structure, which can reduce the probability of the explosion-proof valve bursting and opening in advance.

[0043] Specifically, as Figures 2 to 4 shown, the housing structure 7 includes a first wall body 1, two second wall bodies 2 and two buffer walls 3. Among them, an explosion-proof hole 12 is provided on the first wall body 1, and the explosion-proof valve 11 is welded and sealed at the explosion-proof hole 12. The thickness of the first wall body 1 is T1. The two second wall bodies 2 are respectively located on opposite sides of the first wall body 1. The thickness of the second wall body 2 is T2. The two second wall bodies 2 are respectively connected to the first wall body 1 through a corresponding buffer wall 3. The thickness of the buffer wall 3 is T3, and T2 + T3 ≤ T1.

[0044] Based on the above design, the two second wall bodies 2 are respectively connected to the first wall body 1 through a corresponding buffer wall 3. When the second wall body 2 expands or is extruded by an external force, the second wall body 2 transmits the pulling or extrusion force to the buffer wall 3. Since T2 + T3 ≤ T1, the thickness of the buffer wall 3 is less than the thickness of the first wall body 1. Furthermore, the structural strength of the buffer wall 3 is less than the structural strength of the first wall body 1. When the buffer wall 3 receives the force transmitted by the second wall body 2, the buffer wall 3 deforms. Thus, the influence on the first wall body 1 caused by the expansion of the second wall body 2 or the extrusion by an external force can be greatly reduced, and further the probability of the explosion-proof valve 11 bursting and opening in advance can be reduced.

[0045] The housing structure 7 provided in this embodiment further includes a third wall body 5. The two opposite sides of the third wall body 5 are respectively connected to a corresponding second wall body 2, and the third wall body 5 is disposed opposite to the first wall body 1. The first wall body 1, the third wall body 5, the two second wall bodies 2, and the two buffer walls 3 enclose a containing cavity 6 with an opening, as Figure 2 shown. The housing structure 7 is generally rectangular. Of course, in other embodiments, the housing structure 7 may also be of other shapes, such as a pentagonal prism shape, etc.

[0046] Optionally, T2≥0.5mm. Exemplarily, T2 can be 0.5mm, 0.55mm, or 0.6mm, etc., so that the second wall body 2 has a certain structural strength, reduces the probability of deformation of the second wall body 2, and at the same time reduces the volume and weight of the second wall body 2, thereby reducing the volume and weight of the housing structure 7.

[0047] Optionally, T1≥1mm. Exemplarily, T1 can be 1mm, 1.3mm, or 2mm, etc., so that the first wall body 1 has a certain structural strength. When stamping the explosion-proof hole 12 on the first wall body 1, the problem of deformation of the first wall body 1 can be avoided, and the welding yield rate of the explosion-proof valve 11 can be improved.

[0048] Optionally, T3≥0.4mm. Exemplarily, T3 can be 0.4mm, 0.45mm, or 0.5mm, etc., so that the buffer wall 3 has a certain deformation ability. When the second wall body 2 applies a pulling and squeezing force to the buffer wall 3, the buffer wall 3 can deform to avoid the influence on the first wall body 1 when the second wall body 2 expands or is externally squeezed.

[0049] Optionally, as Figure 3 and Figure 4 shown, the buffer wall 3 is a rounded corner wall 31, that is, both the inner surface and the outer surface of the buffer wall 3 are arc surfaces. On the one hand, it is convenient for extrusion molding, avoiding stress concentration problems on the buffer wall 3 when producing the housing structure 7, and thus can improve the production yield rate of the housing structure 7. On the other hand, when the buffer wall 3 is deformed by force, the rounded corner wall 31 can disperse stress, avoid stress concentration problems, reduce the probability of fracture of the buffer wall 3, and reduce the probability of the buffer wall 3 transmitting the above-mentioned force to the first wall body 1.

[0050] In other embodiments, the buffer wall 3 may also be of other shapes. For example, the buffer wall 3 includes a plurality of sub-wall bodies, the plurality of sub-wall bodies are connected in sequence, and each sub-wall body is flat, so that the buffer wall 3 is generally a right-angle wall with edges.

[0051] Furthermore, as Figure 5As shown, the inner surface of the rounded corner wall 31 and the inner surface of the first wall body 1 are connected by a transition surface 4. The transition surface 4 is a smooth curved surface. One side of the transition surface 4 is tangent to the inner surface of the rounded corner wall 31, and the other side of the transition surface 4 is tangent to the inner surface of the first wall body 1. That is, the transition surface 4 is generally S-shaped. This design is beneficial to the extrusion molding of the housing structure 7, especially at the positions where the transition surface 4, the transition surface 4 is connected to the inner surface of the first wall body 1, and the transition surface 4 is connected to the inner surface of the buffer wall 3, avoiding stress concentration problems during the extrusion molding of the above three regions, which is beneficial to improving the product yield of the housing structure 7. Moreover, the design of the transition surface 4 as a smooth curved surface is beneficial to dispersing the stress in the transition surface 4 region, avoiding stress concentration in this region, and thus can reduce the fracture probability of this region.

[0052] It can be understood that the thickness of the wall body in the transition surface 4 region (hereinafter referred to as the transition region 41) changes gradually. As Figure 4 shown, the side of the transition region 41 facing the buffer wall 3 is the thinnest, and the side of the transition region 41 facing the first wall body 1 is the thickest. Along the direction from the buffer wall 3 to the first wall body 1, the thickness of the transition region 41 gradually increases. Therefore, compared with the first wall body 1, the structural strength of the transition region 41 is lower. When the second wall body 2 deforms due to expansion or extrusion, there is also a probability that the transition region 41 deforms: if the deformation amount of the second wall body 2 is small, the pulling and extrusion force applied by the second wall body 2 to the buffer wall 3 is small, making the deformation amount of the buffer wall 3 small. The small deformation of the buffer wall 3 can eliminate the influence of the deformation of the second wall body 2 on the first wall body 1. At this time, the transition region 41 does not deform; if the deformation amount of the second wall body 2 is large, the pulling and extrusion force applied by the second wall body 2 to the buffer wall 3 is large, making the deformation amount of the buffer wall 3 large. At this time, the force applied by the buffer wall 3 to the transition region 41 causes the transition region 41 to deform, and the deformation of the transition region 41 can reduce the probability of the influence on the first wall body 1 when the second wall body 2 deforms greatly.

[0053] As Figure 2 and Figure 6 shown, when the housing structure 7 expands, the second wall body 2 deforms in the x direction away from the accommodation cavity 6. When the second wall body 2 is squeezed, the second wall body 2 deforms in the x direction towards the accommodation cavity 6. Therefore, the expansion and extrusion force applied by the deformed second wall body 2 to the buffer wall 3 is mainly parallel to the x direction. To enable the buffer wall 3 and the transition region 41 to have a certain structural strength so that they can resist the force parallel to the x direction, in this embodiment, as Figure 4As shown, the distance between the position where the transition surface 4 is tangent to the inner surface of the first wall body 1 and the inner surface of the second wall body 2 is L, and L / T2≥4. Exemplarily, L / T2 can be 4, 5, 5.5, etc., to ensure that the buffer wall 3 and the transition zone 41 have a certain anti-deformation ability (especially the anti-deformation ability parallel to the x direction), thereby further reducing the probability that the deformation of the second wall body 2 affects the first wall body 1.

[0054] It should be noted that the above inner surface refers to the surface facing the accommodation cavity 6. Specifically, the inner surface of the first wall body 1 refers to the surface of the first wall body 1 facing the accommodation cavity 6, the inner surface of the second wall body 2 refers to the surface of the second wall body 2 facing the accommodation cavity 6, and the inner surface of the buffer wall 3 refers to the surface of the buffer wall 3 facing the accommodation cavity 6.

[0055]

[0056] Table 1 provides six groups of examples and five groups of comparative examples. The material of the explosion-proof valve 11 in the six groups of examples and the five groups of comparative examples is imported aluminum alloy MXF2, and the material of the housing structure 7 is aluminum of the third series.

[0057] In Example 1, the thickness T1 of the first wall body 1 is 1 mm, the thickness T2 of the second wall body 2 is 0.5 mm, the thickness T3 of the buffer wall 3 is 0.4 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall body 1 and the inner surface of the second wall body 2 is 2 mm, T2+T3 = 0.9 mm, L / T2 is 4. The battery cell accelerated expansion test, vibration test, and simulation test all pass. The simulation strain threshold of the explosion-proof valve 11 ≤ 10%, and the first wall body 1 has no deformation. The helium leak detection pass rate of the battery cell meets the requirements, and there is no problem of the explosion-proof valve 11 cracking (that is, the explosion-proof valve 11 explodes and opens in advance when the internal pressure of the housing structure 7 does not reach the bursting value). All indicators of the battery cell meet the technical requirements.

[0058] In Example 2, the thickness T1 of the first wall body 1 is 1 mm, the thickness T2 of the second wall body 2 is 0.5 mm, the thickness T3 of the buffer wall 3 is 0.45 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall body 1 and the inner surface of the second wall body 2 is 2.3 mm, T2+T3 = 0.95 mm, L / T2 is 4.6. The battery cell accelerated expansion test, vibration test, and simulation test all pass. The simulation strain threshold of the explosion-proof valve 11 ≤ 10%, and the first wall body 1 has no deformation. The helium leak detection pass rate of the battery cell meets the requirements, and there is no problem of the explosion-proof valve 11 cracking (that is, the explosion-proof valve 11 explodes and opens in advance when the internal pressure of the housing structure 7 does not reach the bursting value). All indicators of the battery cell meet the technical requirements.

[0059] In Embodiment 3, the thickness T1 of the first wall 1 is 1 mm, the thickness T2 of the second wall 2 is 0.5 mm, the thickness T3 of the buffer wall 3 is 0.5 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall 1 and the inner surface of the second wall 2 is 2.5 mm, T2 + T3 = 1 mm, L / T2 is 5. The battery cell accelerated expansion test, vibration test, and simulation test are all passed. The simulated strain threshold of the explosion-proof valve 11 is ≤ 10%, and the first wall 1 has no deformation. The helium leak detection pass rate of the battery cell meets the requirements, and there is no problem of the explosion-proof valve 11 cracking (i.e., the explosion-proof valve 11 explodes and opens in advance when the internal pressure of the housing structure 7 does not reach the bursting value). All indicators of the battery cell meet the technical requirements.

[0060] In Embodiment 4, the thickness T1 of the first wall 1 is 1.2 mm, the thickness T2 of the second wall 2 is 0.6 mm, the thickness T3 of the buffer wall 3 is 0.45 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall 1 and the inner surface of the second wall 2 is 2.4 mm, T2 + T3 = 1.05 mm, L / T2 is 4. The battery cell accelerated expansion test, vibration test, and simulation test are all passed. The simulated strain threshold of the explosion-proof valve 11 is ≤ 10%, and the first wall 1 has no deformation. The helium leak detection pass rate of the battery cell meets the requirements, and there is no problem of the explosion-proof valve 11 cracking (i.e., the explosion-proof valve 11 explodes and opens in advance when the internal pressure of the housing structure 7 does not reach the bursting value). All indicators of the battery cell meet the technical requirements.

[0061] In Embodiment 5, the thickness T1 of the first wall 1 is 1.2 mm, the thickness T2 of the second wall 2 is 0.6 mm, the thickness T3 of the buffer wall 3 is 0.55 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall 1 and the inner surface of the second wall 2 is 2.5 mm, T2 + T3 = 1.15 mm, L / T2 is 4.17. The battery cell accelerated expansion test, vibration test, and simulation test are all passed. The simulated strain threshold of the explosion-proof valve 11 is ≤ 10%, and the first wall 1 has no deformation. The helium leak detection pass rate of the battery cell meets the requirements, and there is no problem of the explosion-proof valve 11 cracking (i.e., the explosion-proof valve 11 explodes and opens in advance when the internal pressure of the housing structure 7 does not reach the bursting value). All indicators of the battery cell meet the technical requirements.

[0062] In Embodiment 6, the thickness T1 of the first wall 1 is 1.2 mm, the thickness T2 of the second wall 2 is 0.6 mm, the thickness T3 of the buffer wall 3 is 0.6 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall 1 and the inner surface of the second wall 2 is 2.8 mm, T2 + T3 = 1.2 mm, L / T2 is 4.67. The battery cell acceleration expansion test, vibration test, and simulation test are all passed. The simulated strain threshold of the explosion-proof valve 11 is ≤ 10%, and the first wall 1 has no deformation. The helium leak detection pass rate of the battery cell meets the requirements, and there is no problem of the explosion-proof valve 11 cracking (that is, the explosion-proof valve 11 explodes and opens in advance when the internal pressure of the housing structure 7 does not reach the bursting value). All indicators of the battery cell meet the technical requirements.

[0063] In Comparative Example 1, the thickness T1 of the first wall 1 is 1 mm, the thickness T2 of the second wall 2 is 0.5 mm, the thickness T3 of the buffer wall 3 is 0.6 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall 1 and the inner surface of the second wall 2 is 2.3 mm, T2 + T3 = 1.1 mm, L / T2 is 4.6. The battery cell acceleration expansion test, vibration test, and simulation test are all passed. The simulated strain threshold of the explosion-proof valve 11 is ≤ 7%, and the first wall 1 has no deformation. During the entire life cycle of the battery cell, there is a problem of valve opening and liquid leakage, that is, when the internal pressure of the housing structure 7 does not reach the bursting value, the explosion-proof valve 11 explodes and opens in advance, causing electrolyte leakage.

[0064] In Comparative Example 2, the thickness T1 of the first wall 1 is 1 mm, the thickness T2 of the second wall 2 is 0.5 mm, the thickness T3 of the buffer wall 3 is 0.65 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall 1 and the inner surface of the second wall 2 is 2.3 mm, T2 + T3 = 1.15 mm, L / T2 is 4.6. The battery cell acceleration expansion test, vibration test, and simulation test are all passed. The simulated strain threshold of the explosion-proof valve 11 is ≤ 7.6%, and the first wall 1 has no deformation. During the entire life cycle of the battery cell, there is a problem of valve opening and liquid leakage, that is, when the internal pressure of the housing structure 7 does not reach the bursting value, the explosion-proof valve 11 explodes and opens in advance, causing electrolyte leakage.

[0065] In Comparative Example 3, the thickness T1 of the first wall 1 is 1 mm, the thickness T2 of the second wall 2 is 0.5 mm, the thickness T3 of the buffer wall 3 is 0.5 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall 1 and the inner surface of the second wall 2 is 1.8 mm, T2 + T3 = 1 mm, L / T2 is 3.6. The battery single-cell accelerated expansion test, vibration test, and simulation test all pass. The simulated strain threshold of the explosion-proof valve 11 ≤ 7%, and the first wall 1 has no deformation. During the entire life cycle of the battery single-cell, there is a problem of valve opening and liquid leakage, that is, when the internal pressure of the housing structure 7 does not reach the bursting value, the explosion-proof valve 11 bursts open in advance, causing electrolyte leakage problems.

[0066] In Comparative Example 4, the thickness T1 of the first wall 1 is 1.2 mm, the thickness T2 of the second wall 2 is 0.6 mm, the thickness T3 of the buffer wall 3 is 0.5 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall 1 and the inner surface of the second wall 2 is 2.3 mm, T2 + T3 = 1.1 mm, L / T2 is 3.83. The battery single-cell accelerated expansion test, vibration test, and simulation test all pass. The simulated strain threshold of the explosion-proof valve 11 ≤ 7%, and the first wall 1 has no deformation. During the entire life cycle of the battery single-cell, there is a problem of valve opening and liquid leakage, that is, when the internal pressure of the housing structure 7 does not reach the bursting value, the explosion-proof valve 11 bursts open in advance, causing electrolyte leakage problems.

[0067] In Comparative Example 5, the thickness T1 of the first wall 1 is 1.2 mm, the thickness T2 of the second wall 2 is 0.6 mm, the thickness T3 of the buffer wall 3 is 0.55 mm, the distance L between the position where the transition surface 4 is tangent to the inner surface of the first wall 1 and the inner surface of the second wall 2 is 2.2 mm, T2 + T3 = 1.15 mm, L / T2 is 3.67. The battery single-cell accelerated expansion test, vibration test, and simulation test all pass. The simulated strain threshold of the explosion-proof valve 11 ≤ 7%, and the first wall 1 has no deformation. During the entire life cycle of the battery single-cell, there is a problem of valve opening and liquid leakage, that is, when the internal pressure of the housing structure 7 does not reach the bursting value, the explosion-proof valve 11 bursts open in advance, causing electrolyte leakage problems.

[0068] In summary, when T2 + T3 ≤ T1, L / T2 ≥ 4, and T2 ≥ 0.5 mm, after the battery single-cell passes the accelerated expansion test, vibration test, and simulation test, the first wall 1 will not deform, and there will be no problem of cracking of the explosion-proof valve 11 during the entire life cycle of the battery single-cell, and all indicators of the battery single-cell can meet the technical requirements.

[0069] In this embodiment, an extrusion molding process is adopted to prepare the housing structure 7. A stamping process is used to stamp an explosion-proof hole 12 on the first wall 1, and a welding process is used to weld and fix the explosion-proof valve 11 at the explosion-proof hole 12. The above extrusion molding process, stamping process, and welding process are all relatively mature production processes in the art. Moreover, the design of the buffer wall 3 as a rounded corner wall 31 and the design of the transition surface 4 can both improve the manufacturing yield of the housing structure 7, which is conducive to realizing the automated batch production of the housing structure 7 and the battery cell.

[0070] This embodiment also provides a battery cell, as Figure 7 shown. The battery cell includes a pole group (not shown in the figure), a cover plate 8, and the above housing structure 7. The pole group is arranged in the accommodation cavity 6, and the cover plate 8 seals the opening of the accommodation cavity 6. The battery cell adopts the above housing structure 7. When the battery cell expands or is squeezed, the influence of the second wall 2 on the first wall 1 equipped with the explosion-proof valve 11 is relatively small, thereby reducing the probability of the explosion-proof valve 11 bursting and opening in advance, making the battery cell have a high usage safety.

[0071] Compared with arranging the explosion-proof valve 11 on the cover plate 8, in this embodiment, the explosion-proof valve 11 is arranged on the first wall 1 of the housing structure 7. When the explosion-proof valve 11 bursts and exhausts gas, the path for the gas in the accommodation cavity 6 to flow to the explosion-proof valve 11 is shorter, which is conducive to quickly discharging the high-pressure gas in the accommodation cavity 6 and has the effect of improving the usage safety of the battery cell.

[0072] This embodiment also provides a battery module, which includes the above battery cell. Therefore, the battery module has a high usage safety.

[0073] This embodiment also provides a battery pack, which includes a box body and the above battery module. The battery module is installed in the box body, and the battery pack has a high usage safety.

[0074] Obviously, the above embodiments of the present invention are merely 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. Shell structure, characterized in that, include: A first wall body (1), wherein an explosion-proof valve (11) is provided on the first wall body (1), and the thickness of the first wall body (1) is T1; Two second walls (2), the two second walls (2) being respectively located on two opposite sides of the first wall (1), and the thickness of the second wall (2) being T2; Two buffer walls (3), the two second wall bodies (2) are respectively connected to the first wall body (1) through a corresponding one of the buffer walls (3), the thickness of the buffer wall (3) is T3, T2+T3≤T1.

2. The housing structure according to claim 1, characterized in that: The buffer wall (3) is a rounded wall (31).

3. The housing structure according to claim 2, characterized in that: The inner surface of the rounded wall (31) is connected to the inner surface of the first wall body (1) via a transition surface (4); the transition surface (4) is a smooth curved surface; one side of the transition surface (4) is tangent to the inner surface of the rounded wall (31); and the other side of the transition surface (4) is tangent to the inner surface of the first wall body (1).

4. The housing structure according to claim 3, characterized in that: The distance between the position where the transition surface (4) is tangent to the inner surface of the first wall (1) and the inner surface of the second wall (2) is L, and L / T2≥4.

5. The housing structure according to claim 1, characterized in that: T2≥0.5mm.

6. The housing structure according to claim 1, characterized in that: T1≥1mm.

7. The housing structure according to claim 1, characterized in that: T3≥0.4mm.

8. A battery cell, characterized in that: It comprises a pole group and a shell structure (7) as claimed in any one of claims 1 to 7, wherein the shell structure (7) is provided with a receiving cavity (6), and the pole group is arranged in the receiving cavity (6).

9. A battery module, characterized in that: Comprising the battery cell according to claim 8.

10. A battery pack, characterized in that: Comprising the battery module as claimed in claim 9.

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