Battery cell casing comprising a stepped explosion-proof valve, and manufacturing process therefor

Abstract

The present invention relates to the technical field of batteries, and provides a battery cell casing comprising a stepped explosion-proof valve, and a manufacturing process therefor. The battery cell casing comprising the stepped explosion-proof valve comprises: a casing, an explosion-proof valve mounting hole being formed in a side surface of the casing; and an explosion-proof valve comprising a valve body, a skirt edge being provided along the edge of the valve body, and a first step portion being provided on the skirt edge, wherein by means of the first step portion, the skirt edge overlaps the outer plane of the casing where the explosion-proof valve mounting hole is located, or the inner plane of the casing where the explosion-proof valve mounting hole is located overlaps the first step portion of the skirt edge, and the first step portion and the side surface of the casing where the explosion-proof valve mounting hole is located are fixed by welding. In the present invention, the skirt edge of the explosion-proof valve is configured to be of a step-shaped structure, so that the strength of the connection position of the explosion-proof valve and the casing is increased, the thickness of the side surface of the casing where the explosion-proof valve is located does not need to be wholly increased, and the machining difficulty and material costs of the whole battery cell casing are reduced.

Description

A battery core shell with a stepped explosion-proof valve and its preparation process Technical Field

[0001] The present invention belongs to the technical field of batteries and relates to a battery core shell, in particular to a battery core shell with a stepped explosion-proof valve and a preparation process thereof. Background Art

[0002] With the rapid development of lithium-ion battery technology, people have also put forward higher requirements for the safety performance of lithium-ion batteries. The pressure relief mechanism on the lithium-ion battery has a vital impact on the safety performance of the lithium-ion battery. For example, when the lithium-ion battery is short-circuited or overcharged, it may cause thermal runaway inside the lithium-ion battery and cause the internal air pressure to rise sharply. At this time, the pressure relief mechanism needs to be actuated to release the internal air pressure to the outside, thereby preventing the lithium-ion battery from exploding. As a key reliability structural unit, the explosion-proof valve plays a vital role in the stability of the shell strength.

[0003] The existing battery explosion-proof valve is installed on the shell of the battery cell, especially the current blade battery. The battery cell is thin. Starting the explosion-proof valve installation hole on the narrow side of the battery cell shell will greatly reduce the rigidity of the narrow side of the battery cell shell. When the internal pressure of the battery cell increases, the battery cell will be slightly deformed. Due to the existence of the installation hole, the deformation resistance of the battery shell at the installation hole is reduced. Therefore, the battery cell shell is prone to tearing at the installation hole, which in turn causes damage to the battery cell shell and the fall-off of the explosion-proof valve, seriously affecting the safety of the battery cell.

[0004] In order to improve the strength of the side where the explosion-proof valve installation hole is located, the thickness of the side where the explosion-proof valve installation hole is located is generally increased. However, such a structural design will increase the processing difficulty and increase the material cost of the battery cell shell. Technical issues

[0005] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a battery cell shell with a stepped explosion-proof valve, which can improve the strength of the location where the explosion-proof valve mounting hole is located and avoid the increase in processing difficulty and material cost. Technical Solutions

[0006] The purpose of the present invention is to address the above-mentioned problems in the existing technology and to propose a battery core shell that can improve the strength of the location where the explosion-proof valve mounting hole is located and avoid the increase in processing difficulty and material cost.

[0007] The purpose of the present invention can be achieved through the following technical solutions: A battery core shell with a stepped explosion-proof valve, comprising:

[0008] A shell, and an explosion-proof valve mounting hole is provided on the side of the shell, wherein the inner and outer side surfaces of the shell side where the explosion-proof valve mounting hole is located are the shell inner plane and the shell outer plane respectively;

[0009] An explosion-proof valve includes a valve body, a skirt is provided along the edge of the valve body, and a first step portion is provided on the skirt, wherein the skirt is overlapped on the outer plane of the shell where the explosion-proof valve mounting hole is located through the first step portion to realize the external placement of the first step portion on the skirt; or the inner plane of the shell where the explosion-proof valve mounting hole is located is overlapped on the first step portion of the skirt to realize the internal placement of the first step portion on the skirt, and the explosion-proof valve and the shell are welded and fixed.

[0010] In the above-mentioned battery cell shell with a stepped explosion-proof valve, the first step portion includes a first step and a second step, and the first step is connected to the valve body, and the second step is connected to the first step, wherein the explosion-proof valve is fixed by welding the second step to the shell.

[0011] In the above-mentioned battery cell shell with a stepped explosion-proof valve, the inner and outer side surfaces of the first step are respectively the first step inner plane and the first step outer plane, and the inner and outer side surfaces of the second step are respectively the second step inner plane and the second step outer plane, wherein, when the first step portion on the skirt is externally positioned, the second step inner plane contacts and abuts against the outer plane of the shell; when the first step portion on the skirt is internally positioned, the first step outer plane contacts and abuts against the inner plane of the shell.

[0012] In the above-mentioned battery cell shell with a stepped explosion-proof valve, when the first step portion on the skirt is placed outside, the outer plane of the first step and the inner plane of the second step are staggered; when the first step portion on the skirt is placed inside, the outer plane of the first step and the inner plane of the second step coincide with each other.

[0013] In the above-mentioned battery cell shell with a stepped explosion-proof valve, the inner plane of the shell and the inner plane of the first step are on the same plane, or the distance between the inner plane of the shell and the outer plane of the shell is greater than the distance between the inner plane of the first step and the outer plane of the shell.

[0014] In the above-mentioned battery cell shell with a stepped explosion-proof valve, when the first step portion on the skirt is built in, a second step portion is further provided on one side of the shell where the explosion-proof valve mounting hole is located, and the second step portion and the first step portion are stacked up and down.

[0015] In the above-mentioned battery cell shell with a stepped explosion-proof valve, when the first step portion on the skirt is built-in, the outer plane of the second step and the outer plane of the shell are on the same plane, or the distance between the outer plane of the second step and the inner plane of the shell is smaller than the distance between the inner plane of the shell and the outer plane of the shell.

[0016] In the above-mentioned battery cell housing with a stepped explosion-proof valve, the thickness of the side surface of the housing where the explosion-proof valve mounting hole is located is 0.2 mm to 0.8 mm.

[0017] In the above-mentioned battery cell shell with a stepped explosion-proof valve, the valve body is arranged in a convex surface or a concave surface.

[0018] In the above-mentioned battery cell shell with a stepped explosion-proof valve, the valve body and the skirt are integrally arranged.

[0019] The present invention also provides a battery, comprising the battery core shell with the stepped explosion-proof valve.

[0020] The present invention also provides a process for preparing a battery cell housing having a stepped explosion-proof valve. When the first stepped portion on the skirt is externally positioned, the process comprises the following steps:

[0021] S1. Place the aluminum material on the production line and pass it through the leveling machine for leveling treatment;

[0022] S2. The flattened aluminum material is subjected to multiple rolling processes, and the aluminum material is gradually rolled up to form an initial shell with an elliptical cross-section and an open gap;

[0023] S3, connecting the opening gaps of the initial shell together by high-frequency welding;

[0024] S4. Remove the raised weld beads at the welding point to make the welding point smooth;

[0025] S5, shaping the initial shell having an elliptical cross section into a rectangular cross section by a shaping machine;

[0026] S6, cutting to form a single shell;

[0027] S7, performing precision cutting and shaping on the cutout of the single shell to obtain the shell;

[0028] S8, punching to form an explosion-proof valve installation hole on the side of the shell;

[0029] S9, then embed the explosion-proof valve into the explosion-proof valve installation hole of the housing, and complete the connection between the explosion-proof valve and the housing by welding;

[0030] When the first step on the skirt is built-in, the preparation process includes the following steps:

[0031] S1. Place the aluminum material on the production line and pass it through the leveling machine for leveling treatment;

[0032] S2. The flattened aluminum material is subjected to multiple rolling processes, and the aluminum material is gradually rolled up to form an initial shell with an elliptical cross-section and an open gap;

[0033] S3, connecting the opening gaps of the initial shell together by high-frequency welding;

[0034] S4. Remove the raised weld beads at the welding point to make the welding point smooth;

[0035] S5, shaping the initial shell having an elliptical cross section into a rectangular cross section by a shaping machine;

[0036] S6, cutting to form a single shell;

[0037] S7, performing precision cutting and shaping on the cutout of the single shell to obtain the shell;

[0038] S8, punching to form an explosion-proof valve installation hole on the side of the shell;

[0039] S9. stamping a second step portion on the side of the housing where the explosion-proof valve mounting hole is located;

[0040] S10, then embed the explosion-proof valve into the explosion-proof valve installation hole of the shell, and complete the connection between the explosion-proof valve and the shell by welding.

[0041] Preferably, the thickness of the aluminum material is less than 0.8 mm.

[0042] Preferably, the number of multi-pass rolling is any integer between 6 and 15. The cross-section of the aluminum material formed by each rolling pass is an axisymmetric structure. In each rolling pass, the aluminum material is rolled up toward the axis of symmetry, and the angle of each rolling is 5 to 35 degrees. After 6 to 15 rolling passes, a shell structure with an elliptical cross-section and an open gap is finally formed.

[0043] As shown in Figure 7, the edge of the aluminum profile is warped. The warping point is A, the intersection of the symmetry axis of the aluminum profile's cross section with the aluminum profile's cross section is O, and the angle β between the line between A and O and the symmetry axis of the aluminum profile's cross section is β. The angle of each roll is the difference between the angle β of the aluminum profile obtained from the previous roll and the angle β of the current roll.

[0044] The roller assembly structure used in each rolling pass is different and is generally divided into two types: Type I and Type II. Type I roller assemblies consist of upper and lower rollers. The upper roller has a circumferential flange, while the lower roller has an annular groove. The flange of the upper roller and the annular groove of the lower roller cooperate to roll the aluminum into a specific shape. The structure of the Type I roller assembly used in each rolling pass is different, specifically the structure of the flange and the annular groove.

[0045] The second type of roller assembly consists of an upper roller and a lower roller. The upper roller has an upper groove along its circumference, while the lower roller has a lower groove along its circumference. The upper and lower grooves form a cavity that forms a mold that rolls the aluminum material into a specific shape, particularly an elliptical cross-section. The second type of roller assembly used in each rolling pass is also different, specifically the structure of the upper and lower grooves.

[0046] Preferably, when the angle β is 35-90° (including 35°), the first type of roller group is used for rolling; when the angle β is 10-35° (excluding 35°), the second type of roller group is used for rolling.

[0047] Preferably, the width of the opening gap of the initial shell is 0.5-3 mm.

[0048] Preferably, the high-frequency welding is induction high-frequency welding. The specific process of induction high-frequency welding is as follows: the initial shell first passes through a high-frequency induction coil to generate a high-frequency current, causing the opening gap of the initial shell to rapidly heat up and melt. After the initial shell enters the pass of the extrusion roller, the extrusion roller applies pressure to the initial shell, and the melted opening gap is welded to form a weld bead, thereby completing the welding of the opening gap.

[0049] The shape of the initial shell obtained in step S2 must correspond to the shape of the squeeze roller pass, so that the initial shell can enter the squeeze roller pass and be squeezed by the squeeze roller to achieve high-frequency welding.

[0050] Preferably, the housing obtained in step S7 is a double-pass structure, which means that the top and bottom surfaces of the housing are open. Beneficial effects

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] 1. The present invention provides a battery cell shell with a stepped explosion-proof valve, in which the skirt of the explosion-proof valve is set in a stepped structure, thereby increasing the strength of the connection between the explosion-proof valve and the shell without increasing the thickness of the side of the shell where the explosion-proof valve is located, thereby reducing the processing difficulty and material cost of the entire battery cell shell.

[0053] 2. The traditional stamping shell has an aluminum utilization rate of only 50-60%, while the shell of the present invention adopts multi-pass roll forming, and the aluminum utilization rate reaches 95%. The shell is prepared by multi-pass roll forming, which greatly improves the production efficiency and the space utilization rate of the shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] FIG1 is a schematic structural diagram of a battery core shell with a stepped explosion-proof valve according to the present invention;

[0055] FIG2 is a cross-sectional view taken along line AA shown in FIG1 ;

[0056] FIG3 is an enlarged structural diagram of point A in FIG2 ;

[0057] FIG4 is a schematic structural diagram of another embodiment of a battery core housing with a stepped explosion-proof valve according to the present invention;

[0058] FIG5 is a cross-sectional view of BB shown in FIG4;

[0059] FIG6 is an enlarged structural diagram of point B in FIG5;

[0060] FIG7 is a cross-sectional view of the aluminum material obtained by each rolling process in Example 3 of the present invention;

[0061] FIG8 is a cross-sectional view of the roller assembly structure used in the second rolling pass in Example 3 of the present invention;

[0062] FIG9 is a cross-sectional view of the roller assembly structure used in the ninth rolling pass in the third embodiment of the present invention.

[0063] In the figure, 10, shell; 11, explosion-proof valve mounting hole; 12, inner plane of shell; 13, outer plane of shell; 14, third step; 15, fourth step; 20, explosion-proof valve; 21, valve body; 22, skirt; 221, first step; 2211, outer plane of first step; 2212, inner plane of first step; 222, second step; 2221, outer plane of second step; 2222, inner plane of second step; 4, symmetry axis of aluminum cross section; 52, upper roller of second rolling pass; 62, lower roller of second rolling pass; 521, flange; 621, annular groove; 59, upper roller of ninth rolling pass; 69, lower roller of ninth rolling pass; 591, upper groove; 691, lower groove; 100, opening gap. Modes for Carrying Out the Invention

[0064] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0065] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly. Example 1

[0066] As shown in Figures 1 to 3, the present invention provides a battery cell shell with a stepped explosion-proof valve, comprising:

[0067] The housing 10 is provided in a frame-shaped structure, and an explosion-proof valve mounting hole 11 is provided on the side of the housing 10;

[0068] The explosion-proof valve 20 includes a valve body 21, a skirt 22 is provided along the edge of the valve body 21, and a first step portion is provided on the skirt 22, wherein the first step portion allows the skirt 22 to be placed on the side of the shell 10 where the explosion-proof valve mounting hole 11 is located, forming an external position of the first step portion on the skirt 22, and the connection between the explosion-proof valve 20 and the shell 10 is completed by welding.

[0069] The present invention provides a battery cell shell with a stepped explosion-proof valve, in which the skirt 22 of the explosion-proof valve 20 is set to a stepped structure, thereby increasing the strength of the connection between the explosion-proof valve 20 and the shell 10 without increasing the thickness of the side of the shell 10 where the explosion-proof valve 20 is located as a whole, thereby reducing the processing difficulty and material cost of the entire battery cell shell.

[0070] Further preferably, the first step portion includes a first step 221 and a second step 222, and the first step 221 is embedded in the explosion-proof valve mounting hole 11 and forms an abutment fit with the hole wall of the explosion-proof valve mounting hole 11, and the second step 222 is placed on the side of the explosion-proof valve mounting hole 11.

[0071] Further preferably, the inner and outer side surfaces of the first step 221 are respectively the first step outer plane 2211 and the first step inner plane 2212, and the inner and outer side surfaces of the second step 222 are respectively the second step outer plane 2221 and the second step inner plane 2222, wherein the inner and outer side surfaces of the side where the explosion-proof valve mounting hole 11 is located are respectively the shell inner plane 12 and the shell outer plane 13, and the shell outer plane 13 contacts and abuts against the second step inner plane 2222, serving as the welding position of the shell 10 and the explosion-proof valve 20.

[0072] Further preferably, the housing inner plane 12 and the first step inner plane 2212 are on the same horizontal plane, or the distance between the housing inner plane 12 and the housing outer plane 13 is greater than the distance between the first step inner plane 2212 and the housing outer plane 13. This prevents scratches on the internal battery cells during assembly, thereby improving the safety of battery cell assembly.

[0073] Further preferably, the first step outer plane 2211 and the second step inner plane 2222 are on the same plane, and the first step outer plane 2211 and the second step inner plane 2222 are separately provided.

[0074] Further preferably, the first step outer plane 2211 and the shell outer plane 13 are on the same horizontal plane.

[0075] Further preferably, the thickness of the side surface of the shell 10 on the side where the explosion-proof valve mounting hole 11 is located is 0.2 mm-0.8 mm, preferably 0.4 mm-0.6 mm, so as to achieve material saving.

[0076] Preferably, the valve body 21 is arranged in a convex surface or a concave surface.

[0077] Further preferably, the surface of the explosion-proof valve 20 is provided with notches. Example 2

[0078] As shown in Figures 4 to 6, the present invention also provides a battery cell shell with a stepped explosion-proof valve, comprising:

[0079] The housing 10 is provided in a frame-shaped structure, and an explosion-proof valve mounting hole 11 is provided on the side of the housing 10;

[0080] The explosion-proof valve 20 includes a valve body 21, a skirt 22 is provided along the edge of the valve body 21, and a first step portion is provided on the skirt 22, wherein the side of the shell 10 where the explosion-proof valve mounting hole 11 is located is overlapped on the first step portion of the skirt 22, forming an internal part of the first step portion on the skirt 22, and the connection between the explosion-proof valve 20 and the shell 10 is completed by welding.

[0081] The present invention provides a battery cell shell with a stepped explosion-proof valve, in which the skirt 22 of the explosion-proof valve 20 is also arranged in a stepped structure. Different from the external first step portion in the first embodiment, the first step portion in this embodiment is arranged internally, which can also increase the strength of the connection between the explosion-proof valve 20 and the shell 10 without increasing the thickness of the side of the shell 10 where the explosion-proof valve 20 is located as a whole, thereby reducing the processing difficulty and material cost of the entire battery cell shell.

[0082] Further preferably, the first step portion includes a first step 221 and a second step 222, and the first step 221 and the second step 222 in Example 1 are staggered up and down, while the first step 221 and the second step 222 in this embodiment are stacked up and down, wherein the second step 222 in Example 1 is placed on the side of the shell 10 where the explosion-proof valve mounting hole 11 is located, so as to realize the external placement of the second step 222, while the side of the shell 10 where the explosion-proof valve mounting hole 11 is located in this embodiment is overlapped on the first step 221, so as to realize the internal placement of the first step 221.

[0083] Further preferably, the first step 221 includes a first step outer plane 2211 and a first step inner plane 2212, the second step 222 includes a second step outer plane 2221 and a second step inner plane 2222, and the side of the shell 10 where the explosion-proof valve mounting hole 11 is located includes a shell inner plane 12 and a shell outer plane 13. Since the first step 221 and the second step 222 in this embodiment are arranged to be superimposed on each other, the first step outer plane 2211 and the second step inner plane 2222 coincide with each other, wherein, in embodiment 1, the second step inner plane 2222 contacts and abuts against the shell outer plane 13, while in this embodiment, the first step outer plane 2211 contacts and abuts against the shell inner plane 12.

[0084] Further preferably, the housing inner plane 12 and the first step inner plane 2212 are on the same horizontal plane, or the distance between the housing inner plane 12 and the housing outer plane 13 is greater than the distance between the first step inner plane 2212 and the housing outer plane 13. This prevents scratches on the internal battery cells during assembly, thereby improving the safety of battery cell assembly.

[0085] It is worth mentioning that in the first embodiment, the first step outer plane 2211 and the shell outer plane 13 are on the same horizontal plane, while in this embodiment, the second step outer plane 2221 and the shell outer plane 13 are on the same horizontal plane.

[0086] Preferably, a second step portion is further provided on the side of the housing 10 where the explosion-proof valve mounting hole 11 is located, and the second step portion includes a third step 14 and a fourth step 15 , wherein the fourth step 15 and the first step 221 are vertically stacked.

[0087] It is worth mentioning that when the first step portion and the second step portion are superimposed on each other, the first step 221 in the first step portion and the third step 14 in the second step portion are arranged opposite to each other, the second step 222 in the first step portion and the fourth step 15 in the second step portion are arranged opposite to each other, and the fourth step 15 and the first step 221 are superimposed in the vertical direction, wherein the relative position between the second step 222 in the first step portion and the fourth step 15 in the second step portion serves as the welding position between the explosion-proof valve 20 and the shell 10.

[0088] In addition, the housing inner plane 12 is the inner surface of the third step 14 in the second stepped portion, and the housing outer plane 13 is the outer surface of the fourth step 15 in the second stepped portion.

[0089] Further preferably, the thickness of the side surface of the shell 10 on the side where the explosion-proof valve mounting hole 11 is located is 0.2 mm-0.8 mm, preferably 0.4 mm-0.6 mm, so as to achieve material saving.

[0090] Preferably, the valve body 21 is arranged in a convex surface or a concave surface.

[0091] Further preferably, the surface of the explosion-proof valve 20 is provided with notches. Example 3

[0092] This embodiment provides a process for preparing a battery cell casing with a stepped explosion-proof valve according to the first embodiment. That is, when the first stepped portion on the skirt of the explosion-proof valve is externally positioned, the process for preparing the battery cell casing with a stepped explosion-proof valve includes the following steps:

[0093] S1. Place the aluminum material with a thickness of 0.7 mm on the production line and pass it through the leveling machine for leveling treatment;

[0094] S2. The flattened aluminum material is subjected to 9 rolling processes, and the aluminum material is gradually rolled up to form an initial shell with an elliptical cross-section and an opening gap 100, where the width of the opening gap 100 is 1.5 mm;

[0095] S3. Connecting the opening gap 100 of the initial shell together by induction high-frequency welding. The specific steps are as follows: the initial shell first passes through a high-frequency induction coil to generate a high-frequency current, causing the opening gap 100 of the initial shell to heat rapidly until it melts. After the initial shell enters the extrusion roller pass, the extrusion roller applies pressure to the initial shell, and the melted opening gap 100 is welded and bonded to form a weld bead, thereby completing the welding of the opening gap 100. The shape of the initial shell obtained in step S2 must correspond to the shape of the extrusion roller pass, so that the initial shell can enter the extrusion roller pass and be squeezed by the extrusion roller to achieve high-frequency welding.

[0096] S4. Remove the raised weld beads at the welding point to make the welding point smooth;

[0097] S5, shaping the initial shell having an elliptical cross section into a rectangular cross section by a shaping machine;

[0098] S6, cutting to form a single shell;

[0099] S7, performing precision cutting and shaping on the cutout of the single shell to obtain the shell;

[0100] S8, punching to form an explosion-proof valve installation hole on the side of the shell;

[0101] S9. Then, the explosion-proof valve is embedded in the explosion-proof valve installation hole of the shell, and the connection between the explosion-proof valve and the shell is completed by welding.

[0102] Figure 7 shows the cross-section of the aluminum material obtained during each rolling process. The cross-section of the aluminum material formed during each rolling process is axisymmetric. With each rolling process, the aluminum material is rolled up toward the axis of symmetry 4 of the cross-section, with each roll-up angle ranging from 5 to 35 degrees. After nine rolling processes, the aluminum material gradually rolls up, ultimately forming a shell structure with an elliptical cross-section and an open gap 100.

[0103] As shown in Figure 7, the edge of the aluminum profile is warped. In the cross section, the warping point is A, the intersection of the symmetry axis 4 of the cross section with the aluminum profile is O, and the angle β between the line between the warping point A and the intersection O and the symmetry axis 4 of the cross section is β. The angle of each roll is the difference between the angle β of the aluminum profile obtained from the previous roll and the angle β of the current roll.

[0104] Each rolling pass uses a different roller assembly structure. In this embodiment, the first to sixth rolling passes use the first type of roller assembly, and the seventh to ninth rolling passes use the second type of roller assembly. The angle β of the aluminum material obtained by the sixth rolling pass is approximately 18°.

[0105] Figure 8 is a cross-sectional view of the roller assembly used in the second rolling pass. The roller assembly includes an upper roller 52 and a lower roller 62. The upper roller 52 has a circumferential flange 521, while the lower roller 62 has a circumferential annular groove 621. The flange 521 of the upper roller 52 and the annular groove 621 of the lower roller 62 cooperate to roll the aluminum material 72 into a specific shape. The first type of roller assembly used in the first through sixth rolling passes differs in structure, specifically in the configuration of the flanges and annular grooves.

[0106] Figure 9 is a cross-sectional view of the roller assembly used in the ninth rolling pass. The roller assembly includes upper roller 59 and lower roller 69. Upper roller 59 is circumferentially provided with an upper groove 591, while lower roller 69 is circumferentially provided with a lower groove 691. The cavity formed by the upper groove 591 of upper roller 59 and the lower groove 691 of lower roller 69 rolls the aluminum material into an elliptical cross-section. The second type of roller assembly used in the seventh through ninth rolling passes differs in structure, specifically in the configuration of the upper and lower grooves. Example 4

[0107] This embodiment provides a preparation process for a battery cell housing with a stepped explosion-proof valve according to the second embodiment. That is, when the first stepped portion on the skirt of the explosion-proof valve is built-in, the preparation process for the battery cell housing with the stepped explosion-proof valve includes the following steps:

[0108] Steps S1-S8 are the same as those in Example 3;

[0109] S9. stamping a second step portion on the side of the housing where the explosion-proof valve mounting hole is located;

[0110] S10, then embed the explosion-proof valve into the explosion-proof valve installation hole of the shell, and complete the connection between the explosion-proof valve and the shell by welding.

[0111] The second step portion includes a third step 14 and a fourth step 15 , and the relative position between the second step 222 in the first step portion and the fourth step 15 in the second step portion serves as a welding position between the explosion-proof valve 20 and the housing 10 .

[0112] It should be noted that, in the present invention, descriptions such as "first", "second", "one", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly defined. The terms "connected", "fixed", etc. should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integral whole; 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, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0113] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0114] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope of the appended claims.

Claims

1. A battery cell shell with a stepped explosion-proof valve, characterized in that: include: A shell, and an explosion-proof valve installation hole is arranged on the side of the shell, wherein the inner and outer side surfaces of one side of the shell where the explosion-proof valve installation hole is located are respectively an inner plane of the shell and an outer plane of the shell; The explosion-proof valve comprises a valve body, a skirt is arranged along the edge of the valve body, and a first step portion is arranged on the skirt, wherein the skirt is overlapped on the outer plane of the shell where the explosion-proof valve mounting hole is located through the first step portion to realize the external placement of the first step portion on the skirt; or the inner plane of the shell where the explosion-proof valve mounting hole is located is overlapped on the first step portion of the skirt to realize the internal placement of the first step portion on the skirt, and the explosion-proof valve is fixed to the shell by welding.

2. The battery cell shell with a stepped explosion-proof valve according to claim 1, characterized in that: The first step portion includes a first step and a second step, and the first step is connected to the valve body, and the second step is connected to the first step, wherein the explosion-proof valve is fixed by welding the second step to the shell.

3. The battery cell shell with a stepped explosion-proof valve according to claim 2, characterized in that: The inner and outer side surfaces of the first step are respectively the inner plane of the first step and the outer plane of the first step, and the inner and outer side surfaces of the second step are respectively the inner plane of the second step and the outer plane of the second step, wherein when the first step portion on the skirt is placed outside, the inner plane of the second step contacts and abuts against the outer plane of the shell; when the first step portion on the skirt is placed inside, the outer plane of the first step contacts and abuts against the inner plane of the shell.

4. The battery cell shell with a stepped explosion-proof valve according to claim 3, characterized in that: When the first step portion on the skirt is external, the outer plane of the first step and the inner plane of the second step are offset; when the first step portion on the skirt is internal, the outer plane of the first step and the inner plane of the second step coincide with each other.

5. The battery cell shell with a stepped explosion-proof valve according to claim 3, characterized in that: The inner plane of the shell and the inner plane of the first step are in the same plane, or the distance between the inner plane of the shell and the outer plane of the shell is greater than the distance between the inner plane of the first step and the outer plane of the shell.

6. The battery cell shell with a stepped explosion-proof valve according to claim 3, characterized in that: When the first step portion on the skirt is built in, a second step portion is further provided on one side of the shell where the explosion-proof valve mounting hole is located, and the second step portion and the first step portion are stacked up and down.

7. The battery cell shell with a stepped explosion-proof valve according to claim 3, characterized in that: When the first step on the skirt is built in, the outer plane of the second step is in the same plane as the outer plane of the shell, or the distance between the outer plane of the second step and the inner plane of the shell is smaller than the distance between the inner plane of the shell and the outer plane of the shell.

8. The battery cell shell with a stepped explosion-proof valve according to claim 1, characterized in that: The thickness of the side of the shell where the explosion-proof valve installation hole is located is 0.2mm-0.8mm.

9. The battery cell shell with a stepped explosion-proof valve according to claim 1, characterized in that: The valve body is arranged in a convex surface or a concave surface.

10. The battery cell shell with a stepped explosion-proof valve according to claim 1, characterized in that: The valve body and the skirt are integrally arranged.

11. A battery, characterized in that: A battery cell shell with a stepped explosion-proof valve as described in any one of claims 1 to 10.

12. The process for preparing a battery cell shell with a stepped explosion-proof valve according to claim 1, characterized in that: When the first step portion on the skirt is external, the following steps are included: S1. Put the aluminum material into the production line and pass it through the leveling machine for leveling treatment; S2, subjecting the flattened aluminum material to a multi-pass rolling process, so that the aluminum material is gradually rolled up to form an initial shell having an elliptical cross section and an open gap; S3, connecting the opening gaps of the initial shell together by high frequency welding; S4. Remove the raised weld beads at the welding point to make the welding point smooth; S5, shaping the initial shell with an elliptical cross section into a rectangular cross section by a shaping machine; S6, cutting to form a single shell; S7, performing precision cutting and shaping processing on the cutout of the single shell to obtain the shell; S8, punching to form an explosion-proof valve installation hole on the side of the shell; S9. Then, the explosion-proof valve is embedded in the explosion-proof valve installation hole of the shell, and the connection between the explosion-proof valve and the shell is completed by welding.

13. The process for preparing a battery cell shell with a stepped explosion-proof valve according to claim 1, characterized in that: When the first step on the skirt is built in, the following steps are included: S1. Put the aluminum material into the production line and pass it through the leveling machine for leveling treatment; S2, subjecting the flattened aluminum material to a multi-pass rolling process, so that the aluminum material is gradually rolled up to form an initial shell having an elliptical cross section and an open gap; S3, connecting the opening gaps of the initial shell together by high frequency welding; S4. Remove the raised weld beads at the welding point to make the welding point smooth; S5, shaping the initial shell with an elliptical cross section into a rectangular cross section by a shaping machine; S6, cutting to form a single shell; S7, performing precision cutting and shaping processing on the cutout of the single shell to obtain the shell; S8, punching to form an explosion-proof valve installation hole on the side of the shell; S9, stamping a second step portion on the side of the shell where the explosion-proof valve mounting hole is located; S10, then embed the explosion-proof valve into the explosion-proof valve installation hole of the shell, and complete the connection between the explosion-proof valve and the shell by welding.

14. The preparation process according to claim 12 or 13, characterized in that: The thickness of aluminum material is less than 0.8mm.

15. The preparation process according to claim 12 or 13, characterized in that: The number of multi-pass rolling is any integer between 6 and 15.

16. The preparation process according to claim 12 or 13, characterized in that: The width of the opening gap of the initial shell is 0.5~3mm.

17. The preparation process according to claim 12 or 13, characterized in that: The high frequency welding is induction high frequency welding.

Images