Assembling structure of battery shell and battery

Abstract

The invention relates to the technical field of batteries, and particularly discloses an assembly structure of a battery shell and a battery. The cover plate comprises a convex part and a lap joint part, during press fitting, the convex part of the cover plate extends into the accommodating cavity of the shell, and the lap joint part is matched with the end part of one side, provided with the opening, of the shell. After the cover plate and the shell are pressed, the height difference h1 exists between the peripheral side wall of the side, away from the body, of the lap joint part and the outer wall of the side, away from the containing cavity, of the shell in the first direction, the wall thickness of the shell is H, and the relation between h1 and H meets the condition that h1 / H | is larger than or equal to 0.15 and smaller than or equal to 0.4. In the second direction, a press-fitting gap K is formed between the end face, facing the side of the shell, of the lap joint part and the end face, facing the side of the lap joint part, of the shell; the value range of K is 0 mm < = K < = 0.3 mm. Therefore, it is guaranteed that the shell and the cover plate are subjected to pre-spot welding smoothly, the welding yield of peripheral welding of the shell and the cover plate is high, the welding strength is high, and the sealing performance meets the requirement. The invention also provides a battery which adopts the assembly structure of the battery shell.

Description

Technical Field

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

[0002] The battery consists of a battery shell and a pole group. The battery shell includes a shell and a cover plate. The shell and the cover plate are welded after being pressed together to form a closed space for installing the pole group. The pole group can be encapsulated by the battery shell. In order to ensure the good airtightness of the closed space where the pole group is located, the welding quality and welding strength of the welding point between the shell and the cover plate are crucial, which is an important factor affecting the sealing performance of the battery shell.

[0003] However, at present, when the cover plate and the shell are press-fitted, the relative positions of the two may not be precisely defined due to the actual manufacturing tolerances of the cover plate and the shell and the tolerance limitations when they are press-fitted by the press-fitting equipment. Pre-spot welding and peripheral welding are directly performed after the shell and the cover plate are press-fitted. There may be problems in the pre-spot welding between the shell and the cover plate, and the shell and the cover plate cannot be well connected together, which leads to low welding strength and poor welding quality at the weld between the shell and the cover plate after peripheral welding, which cannot meet the sealing performance required by the battery and has low reliability of the battery. Summary of the invention

[0004] The object of the present invention is to provide an assembly structure of a battery shell and a battery, which accurately defines the relative position of the cover plate and the shell after press-fitting, ensures that the shell and the cover plate can be pre-spot welded smoothly, and ensures that the welding quality and welding strength are good when the shell and the cover plate are subsequently welded around the perimeter.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In one aspect, the present invention provides an assembly structure of a battery housing, comprising:

[0007] A shell, wherein the interior of the shell is hollow to form a receiving cavity, and at least one side of the shell is provided with an opening communicating with the receiving cavity;

[0008] A cover plate, the cover plate comprising a body, a convex portion and a lap portion, the lap portion being arranged in the circumferential direction of the body, the convex portion being arranged on an end surface of one side of the body, a step being formed between the lap portion and the convex portion, and when press-fitted, the convex portion extends into the accommodating cavity, and the lap portion cooperates with an end portion of the housing on one side of the opening to form a seam;

[0009] Along the first direction, there is a height difference h1 between the peripheral side wall of the overlapping portion facing away from the main body and the outer wall of the shell facing away from the accommodating cavity, the wall thickness of the shell is H, and the relationship between h1 and H satisfies: 0.15≤|h1 / H|≤0.4;

[0010] The value range of h1 is: -0.32mm≤h1≤0.32mm;

[0011] The value range of H is 0.15mm≤H≤1.0mm;

[0012] Along the second direction, a press-fitting gap K is provided between an end surface of the overlapping portion facing the shell and an end surface of the shell facing the overlapping portion; a value range of K is 0 mm ≤ K ≤ 0.3 mm.

[0013] Optionally, the overlapped portion is welded to the end of the shell on the side where the opening is provided to form a welded portion, the welded portion completely covers the seam, and the welded portion penetrates into the convex portion;

[0014] Along the first direction, a distance between an end of the welding portion facing the cover plate and a peripheral side wall of the protrusion is h2, and a value range of h2 is: 0.6 mm ≤ h2 ≤ 2.0 mm.

[0015] Optionally, along the second direction, the weld width of the weld portion is w;

[0016] The relationship between w and h2 satisfies: 0.3≤w / h2≤1.8;

[0017] The value range of w is: 0.5mm≤w≤1.5mm.

[0018] Optionally, a dimension of an end portion of the welding portion that is away from the cover plate and protrudes from the outer wall of the shell is C2, and a value range of C2 is: 0≤C2<0.2mm.

[0019] Optionally, along the second direction, the total thickness of the cover plate is L1, and the size of the overlap portion is L2;

[0020] The relationship between L1 and L2 satisfies: 0.16≤L2 / L1≤0.8;

[0021] The value range of L1 is: 1.5mm≤L1≤3.0mm;

[0022] The value range of L2 is: 0.5mm≤L2≤2.4mm.

[0023] Optionally, the convex portion includes a guiding section and a matching section, the matching section is connected to the body, and the convex portion is installed into the accommodating cavity of the shell under the guidance of the guiding section;

[0024] Along the second direction, the size of the matching segment is L3, and the value range of L3 is: 0.5mm≤L3≤2.4mm.

[0025] Optionally, along the first direction, there is a gap f between the peripheral side wall of the matching segment and the inner wall of the housing; f=h1+△t1+△t2;

[0026] Wherein, Δt1 is the machining tolerance of the inner wall of the shell facing the accommodating cavity along the first direction; Δt2 is the machining tolerance of the peripheral side wall of the matching section along the first direction;

[0027] The value range of △t1 is: -0.1mm≤△t1≤0.1mm;

[0028] The value range of △t2 is: -0.05mm≤△t1≤0.05mm.

[0029] Optionally, the shell includes two oppositely arranged first side panels and two oppositely arranged second side panels, the first side panels and the second side panels form a cylindrical structure, the openings are formed on opposite sides of the shell along the second direction, the area of ​​the first side panel is larger than the area of ​​the second side panel, and the overlapping portion cooperates with the end of the first side panel along the second direction to form a seam.

[0030] On the other hand, the present invention provides a battery, comprising the assembly structure of the battery casing in any of the above schemes.

[0031] Optionally, the battery includes a shell, a positive electrode cover plate and a negative electrode cover plate, and a first opening and a second opening are provided on opposite sides of the shell, and the positive electrode cover plate and the first opening, and / or the negative electrode cover plate and the second opening are connected using the assembly structure of the battery shell.

[0032] The beneficial effects of the present invention are:

[0033] The present invention provides an assembly structure of a battery shell, comprising a shell and a cover plate. An opening is provided on at least one side of the shell. The cover plate comprises a main body, a convex portion and an overlap portion. When pressed, the convex portion of the cover plate extends into the accommodating cavity of the shell along the second direction, and the overlap portion cooperates with the end of the shell on the side with the opening to form a seam. After the cover plate and the shell are pressed, the following conditions are satisfied: along the first direction, there is a height difference h1 between the peripheral side wall of the overlap portion on the side facing away from the main body and the outer wall of the shell on the side facing away from the accommodating cavity, the wall thickness of the shell is H, and the relationship between h1 and H satisfies: 0.15≤|h1 / H∣≤0.4. Along the second direction, there is a press-fitting gap K between the end face of the overlap portion facing the shell side and the end face of the shell facing the overlap portion; the value range of K is 0mm≤K≤0.3mm.

[0034] By ensuring that the values of h1, h1 / H, and K are within the set ranges, it is possible to ensure that the subsequent pre-spot welding between the housing and the cover plate proceeds smoothly. After pre-spot welding, the housing and the cover plate are pre-fixed. Then, circumferential welding is performed around the housing and the cover plate. The welding yield of the two is relatively high, without any welding defects such as welding explosion points or false soldering. The welding strength is relatively high, the housing and the cover plate are successfully assembled, the welding sealing performance is good, the housing and the cover plate enclose a closed space, and the reliability of the battery is high.

[0035] The present invention also provides a battery, including a housing, a positive cover plate, and a negative cover plate. Between the positive cover plate and the first opening of the housing, and between the negative cover plate and the second opening of the housing, the above-mentioned assembly structure of the battery housing is used for connection. By adopting the above structural arrangement, the welding quality between the housing and the positive cover plate, and between the housing and the negative cover plate is good, and the welding strength is relatively high, ensuring that the battery has good sealing performance and relatively high reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description in the embodiments of the present invention. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the content of the embodiments of the present invention and these drawings.

[0037] Figure 1 It is a schematic diagram of the assembly structure (before welding) of the battery housing provided in the embodiment of the present invention;

[0038] Figure 2 It is a schematic diagram of the assembly structure (after welding) of the battery housing provided in the embodiment of the present invention;

[0039] Figure 3 It is an exploded view of the battery provided in the embodiment of the present invention;

[0040] Figure 4 It is a side view of the battery provided in the embodiment of the present invention;

[0041] Figure 5 is Figure 4 a cross-sectional view of the A-A section in

[0042] In the figure:

[0043] 100, housing; 101, opening; 101a, first opening; 101b, second opening; 110, first side plate; 1101, seam; 120, second side plate; 200, cover plate; 200a, positive cover plate; 200b, negative cover plate; 210, body; 220, convex part; 221, guiding section; 222, mating section; 230, overlapping part; 300, welding part; 400a, positive terminal; 400b, negative terminal; 500, electrode group; 510, positive tab; 520, negative tab. Detailed implementation manners

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0045] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, 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, and thus should not be construed as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. Among them, the terms "first position" and "second position" are two different positions, and the first feature being "above", "over" and "on" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature has a higher horizontal height than the second feature. The first feature being "below", "under" and "beneath" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicating that the first feature has a lower horizontal height than the second feature.

[0046] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "mounted", "connected" and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements. 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 situations.

[0047] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0048] like Figure 1 and Figure 2 As shown, this embodiment provides an assembly structure of a battery casing, including a shell 100 and a cover plate 200. The shell 100 is hollow inside to form an accommodating cavity, and at least one side of the shell 100 is provided with an opening 101 connected to the accommodating cavity. The cover plate 200 includes a main body 210, a convex portion 220 and a lap portion 230, wherein the lap portion 230 is arranged in the circumference of the main body 210, and the convex portion 220 is arranged on the end surface of one side of the main body 210, and a step is formed between the lap portion 230 and the convex portion 220, and the shell 100 is provided with an end portion on one side of the opening 101 to cooperate with the step. It should be noted that when the cover plate 200 and the shell 100 are designed in size, in principle, the size of the convex portion 220 of the cover plate 200 along the first direction is equal to the size of the opening 101 of the shell 100 along the first direction, and the size of the lap portion 230 of the cover plate 200 along the first direction is equal to the wall thickness of the shell 100 along the first direction. Among them, the first direction is Figure 1 and Figure 2 The Y-axis direction shown in .

[0049] During press-fitting, the convex portion 220 of the cover plate 200 extends into the accommodating cavity of the shell 100 along the second direction, and the lap joint 230 cooperates with the end of the shell 100 on the side where the opening 101 is provided to form a joint 1101. Due to the problem of the operating accuracy of the assembly tool, there may be a problem of a height difference between the circumferential side wall of the lap joint 230 on the side away from the body 210 and the outer wall of the shell 100 on the side away from the accommodating cavity, and a problem of a press-fitting gap between the end face of the lap joint 230 on the side facing the shell 100 and the end face of the shell 100 on the side facing the lap joint 230, which may cause abnormalities such as cold welding and explosion points when welding between the subsequent shell 100 and the cover plate 200, poor welding quality, low welding strength, and the sealing performance of the battery cannot be guaranteed. It should be noted that the assembly tool is a conventional component in this field, so the specific structure and working principle of the assembly tool are not described in detail in this embodiment.

[0050] Therefore, in order to ensure good welding quality and high welding strength between the subsequent housing 100 and the cover plate 200, CT inspection can be performed on the battery housing before the housing 100 and the cover plate 200 are pre-spot welded and peripherally welded, so as to ensure that the height difference between the peripheral side wall on the side of the overlapping portion 230 away from the body 210 and the outer wall of the housing 100 on the side away from the accommodating cavity, and the pressing gap between the end face of the overlapping portion 230 facing the housing 100 and the end face of the housing 100 facing the overlapping portion 230 are within the set range, so as to ensure that the housing 100 and the cover plate 200 can be smoothly pre-spot welded, and after pre-spot welding, the housing 100 and the cover plate 200 are connected together with good pre-fixing effect; then, the housing 100 and the cover plate 200 are peripherally welded to successfully assemble the housing 100 and the cover plate 200, and the housing 100 and the cover plate 200 enclose a closed space with good sealing performance of the battery.

[0051] Specifically, after the cover plate 200 and the housing 100 are press-fitted, it is satisfied that: along the first direction, there is a height difference h1 between the peripheral side wall on the side of the overlapping portion 230 away from the body 210 and the outer wall of the housing 100 on the side away from the accommodating cavity, the wall thickness of the housing 100 is H, and the relationship between h1 and H satisfies: 0.15 ≤ |h1 / H| ≤ 0.4.

[0052] For example, the value of |h1 / H| can be 0.15, 0.2, 0.3 or 0.4, etc.

[0053] Among them, the value range of h1 is: -0.32 mm ≤ h1 ≤ 0.32 mm. The "-" indicates that the peripheral side wall on the side of the overlapping portion 230 away from the body 210 is higher than the outer wall of the housing 100 on the side away from the accommodating cavity, and the "+" indicates that the peripheral side wall on the side of the overlapping portion 230 away from the body 210 is lower than the outer wall of the housing 100 on the side away from the accommodating cavity. It should be noted that since the dimension of the convex portion 220 of the cover plate 200 along the first direction is equal to the dimension of the opening 101 of the housing 100 along the first direction during dimension design, and the dimension of the overlapping portion 230 of the cover plate 200 along the first direction is equal to the wall thickness of the housing 100 along the first direction. Therefore, when the peripheral side wall on the side of the overlapping portion 230 of the cover plate 200 on one side along the first direction away from the body 210 is lower than the outer wall of the housing 100 on the side away from the accommodating cavity, the peripheral side wall on the side of the overlapping portion 230 of the cover plate 200 on the other side along the first direction away from the body 210 will be higher than the outer wall of the housing 100 on the side away from the accommodating cavity, and the absolute values of the height differences h1 of the overlapping portions 230 on both sides of the cover plate 200 along the first direction after being press-fitted with the housing 100 are equal, and one height difference h1 is positive and the other height difference h1 is negative. Here Figure 1 The case where the height difference h1 is positive is taken as an example for illustration.

[0054] Exemplarily, the value of h1 can be 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.30 mm, 0.32 mm, etc. The value range of H is 0.15 mm ≤ H ≤ 1.0 mm. For example, when the value of h1 is 0.1 mm, the value of H can be 0.67 mm, 0.5 mm, 0.34 mm, 0.25 mm, etc. When the value of h1 is 0.32 mm, the value of H can be 1.0 mm, 0.8 mm, etc. When the value of h1 is 0.2 mm, the value of H can be 1.0 mm, 0.6 mm, 0.7 mm, 0.5 mm, etc.

[0055] Further, after the cover plate 200 and the housing 100 are press-fitted, the following is also satisfied: along the second direction, there is a press-fitting gap K between the end face of the overlapping portion 230 facing the housing 100 and the end face of the housing 100 facing the overlapping portion 230; the value range of K is 0 mm ≤ K ≤ 0.3 mm. For example, the value of K can be 0 mm, 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, etc. Wherein, the second direction is Figure 1 and Figure 2 the X-axis direction shown in

[0056] By ensuring that the values of h1, H, |h1 / H|, and K are within the set ranges, it is possible to ensure that the subsequent pre-spot welding between the housing 100 and the cover plate 200 is carried out smoothly. After the pre-spot welding, the housing 100 and the cover plate 200 are pre-fixed. Then, peripheral welding is carried out in the circumferential direction of the housing 100 and the cover plate 200. The welding yield of the two is relatively high, and there are no poor conditions such as welding explosion points and false welding. The welding strength is relatively high, the housing 100 and the cover plate 200 are successfully assembled, the welding sealability is good, the housing 100 and the cover plate 200 enclose a closed space, and the reliability of the battery is high.

[0057] Optionally, after the peripheral welding between the housing 100 and the cover plate 200, the overlapping portion 230 and the end of the housing 100 on the side with the opening 101 are welded to form a welding portion 300. The welding portion 300 completely covers the joint 1101, and the welding portion 300 extends into the convex portion 220, thereby ensuring that the welding strength between the housing 100 and the cover plate 200 is relatively high and ensuring good sealing at the welding portion 300, meeting the requirements of the battery for the sealing performance.

[0058] Specifically, refer to Figure 2Along the first direction, the distance between the end of the welding portion 300 facing the cover plate 200 and the peripheral side wall of the convex portion 220 is h2, and the value range of h2 is: 0.6 mm ≤ h2 ≤ 2.0 mm. By limiting the value of h2 within the above range, it can ensure that the molten pool formed during the peripheral welding of the cover plate 200 and the housing 100 is relatively large, and the welding strength of the welding portion 300 formed between the housing 100 and the cover plate 200 after welding is relatively high. Exemplarily, the value of h2 can be 0.6 mm, 0.7 mm, 0.8 mm, 1.0 mm, 2.0 mm, etc. Otherwise, when the value of h2 is small, the molten pool formed between the housing 100 and the convex portion 220 is small, resulting in a decrease in welding strength, affecting the sealing performance of the welding portion 300, and reducing the reliability of the battery. Of course, the value of h2 should not be too large either. If the value of h2 is too large, it will affect the structural strength of the cover plate 200, and the reliability of the battery will also decrease when the battery is bumped.

[0059] Along the second direction, the weld width of the welding portion 300 is w, and the relationship between w and h2 satisfies: 0.3 ≤ w / h2 ≤ 1.8. For example, the value of w / h2 can be 0.3, 0.5, 0.8, 1.0, 1.5, 1.8, etc. The value range of w is: 0.5 mm ≤ w ≤ 1.5 mm. For example, when the value of h2 is 0.6 mm, the value of w can be 0.2 mm, 0.3 mm, 0.5 mm, 0.6 mm, 0.9 mm, or 1.0 mm. When the value of h2 is 2.0 mm, the value of w can be 0.6 mm, 1.0 mm, 1.2 mm, or 1.5 mm, etc. By limiting the values of w and w / h2 within the above range, it can ensure that the welding portion 300 can completely cover the joint 1101 between the housing 100 and the cover plate 200, and the welding strength of the welding portion 300 formed between the housing 100 and the cover plate 200 after welding is relatively high, and the sealing is reliable. Otherwise, when the value of w is small, there may be a situation of incomplete welding in the welding portion 300 between the housing 100 and the overlapping portion 230, resulting in a decrease in welding strength, affecting the sealing performance of the welding portion 300, and reducing the reliability of the battery. When the value of w is too large, it will affect the structural strength of the cover plate 200, and the reliability of the battery will also decrease when the battery is bumped.

[0060] Further, the dimension by which the end of the welding portion 300 facing away from the cover plate 200 protrudes from the outer wall of the housing 100 is C2, and the value range of C2 is: 0 ≤ C2 < 0.2 mm. For example, the value of C2 can be 0 mm, 0.1 mm, or 0.2 mm, etc. By limiting the value of C2 within the above range, it can ensure that the height difference in the first direction between the end of the welding portion 300 facing away from the cover plate 200 and the peripheral side wall of the overlapping portion 230, as well as the outer wall of the housing 100, is relatively small, and the outer surfaces of the housing 100 and the cover plate 200 are relatively flat after welding, with good appearance, and the flatness of the battery meets the requirements.

[0061] Continue to see Figure 1 , along the second direction, the total thickness of the cover plate 200 is L1, the size of the overlapping portion 230 is L2, and the relationship between L1 and L2 satisfies: 0.16≤L2 / L1≤0.8. For example, the value of L2 / L1 can be 0.16, 0.2, 0.4, 0.6, 0.8. The value range of L1 is: 1.5mm≤L1≤3.0mm. The value range of L2 is: 0.5mm≤L2≤2.4mm. Exemplarily, when the value of L1 is 1.5mm, the value of L2 is 0.24mm, 0.3mm, 0.6mm, 0.9mm or 1.2mm. When the value of L1 is 3.0mm, the value of L2 is 0.48mm, 0.6mm, 1.2mm, 1.8mm or 2.4mm. By controlling the value of L2 / L1 within the above-mentioned size limit range, it can be ensured that the size of the overlapping portion 230 along the second direction is large enough to meet the welding requirements, while preventing the welding portion 300 formed by the welding of the shell 100 and the cover plate 200 from protruding from the end surface of the overlapping portion 230 away from the shell 100, thereby ensuring the flatness of the cover plate 200 and the appearance of the battery.

[0062] Optionally, the convex portion 220 in this embodiment includes a guide section 221 and a matching section 222, the matching section 222 is connected to the body 210, and the convex portion 220 is installed in the accommodating cavity of the housing 100 under the guidance of the guide section 221. Exemplarily, the matching section 222 is cylindrical, the guide section 221 is frustum-shaped, and the end of the guide section 221 with a larger cross-sectional area along the second direction is connected to the matching section 222. Through the provision of the guide section 221, when the cover plate 200 and the housing 100 are press-fitted, it can play a good guiding role for the cover plate 200, facilitate the assembly of the housing 100 and the cover plate 200, and improve the assembly efficiency and assembly yield.

[0063] Along the second direction, the size of the mating section 222 is L3, and the value range of L3 is: 0.5mm≤L3≤2.4mm. For example, the value of L3 can be 0.5mm, 0.8mm, 1.0mm, 1.5mm, 2.0mm or 2.4mm, etc. By controlling the value of L3 within the above range, it can be ensured that the size of the part where the protrusion 220 and the shell 100 are matched along the second direction is larger, which is conducive to improving the accuracy of positioning the shell 100 and the cover plate 200 when they are pressed together, thereby ensuring that the pre-spot welding and peripheral welding are carried out smoothly, and the welding strength is high and the welding quality is good.

[0064] Further, along the second direction, the dimension of the guiding section 221 is L4, and L1 = L2 + L3 + L4. The value range of L4 is: 0.1 mm ≤ L4 ≤ 0.6 mm. For example, the value of L4 can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, etc. Preferably, it is 0.3 mm. By controlling the value of L4 within the above range, it can be ensured that the guiding section 221 can play a good guiding role when the housing 100 and the cover plate 200 are press-fitted, and the occupied space is small, which is beneficial to improving the space utilization rate inside the housing 100, and the energy density of the battery is relatively high.

[0065] Continue to refer to Figure 1 , along the first direction, in this embodiment, there is a gap f between the circumferential side wall of the mating section 222 and the inner wall of the housing 100, and f = h1 + Δt1 + Δt2. Wherein, Δt1 is the machining tolerance of the inner wall of the housing 100 facing the accommodating cavity along the first direction; Δt2 is the machining tolerance of the circumferential side wall of the mating section 222 along the first direction. The value range of Δt1 is: -0.1 mm ≤ Δt1 ≤ 0.1 mm. For example, the value of Δt1 is -0.1 mm, -0.05 mm, 0 mm, 0.05 mm, 0.1 mm, etc. The value range of Δt2 is: -0.05 mm ≤ Δt1 ≤ 0.05 mm. The value of Δt2 is -0.05 mm, 0 mm, 0.05 mm, etc. It should be noted that by controlling the values of Δt1 and Δt2 within the above value ranges, it can be ensured as much as possible that the convex portion 220 matches the opening 101 of the housing 100, which is beneficial to improving the positioning accuracy when the housing 100 and the cover plate 200 are press-fitted. Thus, it is further ensured that when the values of h1 and K meet their corresponding value ranges, the welding quality between the housing 100 and the cover plate 200 is good, the welding strength is relatively high, and the sealing performance of the battery meets the requirements.

[0066] This embodiment also provides a battery. Refer to Figures 3 - 5, the battery includes a housing 100, a positive electrode cover plate 200a, and a negative electrode cover plate 200b. Among them, the housing 100 includes two relatively arranged first side plates 110 and two relatively arranged second side plates 120. The first side plates 110 and the second side plates 120 together enclose a cylindrical structure. Both opposite sides of the housing 100 in the second direction form openings 101. One of the openings 101 is the first opening 101a, and the other opening 101 is the second opening 101b. The positive electrode cover plate 200a and the first opening 101a, as well as the negative electrode cover plate 200b and the second opening 101b, are connected by the above-mentioned assembly structure of the battery housing. The area of the first side plate 110 is larger than the area of the second side plate 120. The overlapping portion 230 of the positive electrode cover plate 200a cooperates with one end of the first side plate 110 of the housing 100 in the second direction to form a joint 1101, and the overlapping portion 230 of the negative electrode cover plate 200b cooperates with the other end of the first side plate 110 of the housing 100 in the second direction to form a joint 1101. By adopting the above structural arrangement, the welding quality between the housing 100 and the positive electrode cover plate 200a, as well as between the housing 100 and the negative electrode cover plate 200b, is good, and the welding strength is relatively high, ensuring that the battery has good sealing performance and high reliability of the battery.

[0067] Furthermore, the battery further includes a pole group 500. The pole group 500 is arranged inside the housing 100. A positive electrode post 400a is integrated on the positive electrode cover plate 200a, and a negative electrode post 400b is integrated on the negative electrode cover plate 200b. The positive electrode post 400a is connected to the positive electrode tab 510 of the pole group 500, and the negative electrode post 400b is connected to the negative electrode tab 520 of the pole group 500. Thus, the pole group 500 can be connected to an external circuit through the positive electrode post 400a and the negative electrode post 400b to achieve power supply or energy storage.

[0068] Next, the battery housing samples in some specific implementation cases are subjected to a pressure resistance test and a helium leak detection test to explore the influence of the values of the parameters h1, H, |h1 / H|, and K on the welding quality and welding strength between the housing 100 and the cover plate 200. The results are shown in Table 1.

[0069] Among them, the pressure resistance test refers to: continuously filling gas into the battery housing until leakage occurs at the welding joint between the housing 100 and the cover plate 200, then stop filling gas, and detect the pressure of the gas inside the battery housing at this time as P. P is the maximum pressure that the battery housing can withstand, that is, the pressure resistance strength of the battery housing. When P≥1.2MPa, the pressure resistance test of the battery housing passes, and the welding quality and welding strength between the housing 100 and the cover plate 200 are good, meeting the requirements of the battery product.

[0070] Helium leak detection test means: placing the battery case in a sealed space, then filling the inside of the battery case with helium gas at a certain pressure and maintaining it for a period of time, and then detecting the helium content in the sealed space. If the helium leak detection rate in the sealed space is lower than 1×10 -7 / Pa·m 3 / s, it indicates that the welding position between the housing 100 and the cover plate 200 has good sealing performance, and there are no cracks, air leaks or other abnormal problems at the welding joint, and the sealing performance of the battery case meets the requirements.

[0071] The detailed dimensional parameters of the specific battery case and the test results are shown in Table 1 below.

[0072] Table 1

[0073]

[0074] Among Samples 1 to 12, the values of the relevant parameters h1, H, |h1 / H|, and K of the battery case are all within their corresponding set ranges. The housing 100 and the cover plate 200 are well pressed, accurately positioned, and can be successfully pre-spot welded between the housing 100 and the cover plate 200. After pre-spot welding, the housing 100 and the cover plate 200 are well pre-fixed and connected as a whole. Further, the overlapping part 230 of the housing 100 and the cover plate 200 is subjected to peripheral welding to form a welded part 300. The structural parameters w, h2, and w / h2 of the welded part 300 all meet their corresponding dimensional limit ranges. The welding quality between the housing 100 and the cover plate 200 is good, the welding strength is high, and both the pressure resistance test and the helium leak detection test are passed, and the product is good.

[0075] In Samples 13 to 18, the values of the parameter K are all greater than the maximum value of its set range of 0mm ≤ K ≤ 0.3mm. The parameters h1, H, and |h1 / H| are within their corresponding set ranges. However, at this time, the housing 100 and the cover plate 200 are poorly pressed, and the positioning between them is inaccurate. The pre-spot welding between the housing 100 and the cover plate 200 fails, and the housing 100 and the cover plate 200 cannot be connected as a whole. Then, the overlapping part 230 of the housing 100 and the cover plate 200 is subjected to peripheral welding to form a welded part 300. The structural parameters w, h2, and w / h2 of the welded part 300 cannot simultaneously meet their corresponding dimensional limit ranges. The welding quality between the housing 100 and the cover plate 200 is poor, the welding strength is insufficient, the pressure resistance of the battery case is low, the pressure resistance test fails, the product is defective, and it is not recommended to use.

[0076] Among Samples 19 to 24, the value of parameter K is within its set range of 0 mm ≤ K ≤ 0.3 mm, but the value of parameter |h1 / H| is greater than the maximum value of its set range of 0.15 ≤ |h1 / H| ≤ 0.4. At this time, both the housing 100 and the cover plate 200 have a probability of poor press-fitting. The pre-spot welding between the housing 100 and the cover plate 200 cannot be 100% successful. For example, the pre-spot welding fails in Samples 21, 22, and 24, and it cannot be guaranteed that the housing 100 and the cover plate 200 can be connected as a whole. Subsequently, the overlapping portion 230 of the housing 100 and the cover plate 200 is subjected to peripheral welding to form the welded portion 300. Regardless of whether the structural parameters w, h2, and w / h2 of the welded portion 300 meet their corresponding dimensional limit ranges, the welding quality between the housing 100 and the cover plate 200 is poor, the welding strength is insufficient, the pressure resistance of the battery housing is low, and the pressure resistance test fails. In addition, in Sample 19, its helium leak detection rate is high, and the sealing performance of the battery housing cannot be guaranteed. Therefore, the product is defective and not recommended for use.

[0077] Thus, when the values of h1, H, |h1 / H|, and K all meet their set ranges, it can be ensured that the subsequent pre-spot welding between the housing 100 and the cover plate 200 is carried out smoothly. After the pre-spot welding, the housing 100 and the cover plate 200 are connected as a whole. Subsequently, the overlapping portion 230 of the housing 100 and the cover plate 200 is subjected to peripheral welding. The welding yield is high, and there are no defective conditions such as welding explosion points and false soldering. The welding strength is high, the sealing performance after welding of the housing 100 and the cover plate 200 is good, the product meets the requirements, and the reliability of the battery is high.

[0078] Obviously, the above are only the preferred embodiments of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments here. Various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, it can also include more other equivalent embodiments, and the scope of the present invention is determined by the scope of the appended claims.

[0079] Note that in the description of this specification, the descriptions referring to terms such as "some embodiments" and "other embodiments" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

Claims

1. A battery housing assembly structure, characterized in that: include: A shell, wherein the interior of the shell is hollow to form a receiving cavity, and at least one side of the shell is provided with an opening communicating with the receiving cavity; A cover plate, the cover plate comprising a body, a convex portion and a lap portion, the lap portion being arranged in the circumferential direction of the body, the convex portion being arranged on an end surface of one side of the body, a step being formed between the lap portion and the convex portion, and when press-fitted, the convex portion extends into the accommodating cavity, and the lap portion cooperates with an end portion of the housing on one side of the opening to form a seam; Along the first direction, there is a height difference h1 between the peripheral side wall of the overlapping portion facing away from the main body and the outer wall of the shell facing away from the accommodating cavity, the wall thickness of the shell is H, and the relationship between h1 and H satisfies: 0.15≤|h1 / H|≤0.4; The value range of h1 is: -0.32mm≤h1≤0.32mm; The value range of H is 0.15mm≤H≤1.0mm; Along the second direction, a press-fitting gap K is provided between an end surface of the overlapping portion facing the shell and an end surface of the shell facing the overlapping portion; The value range of K is 0mm≤K≤0.3mm.

2. The assembly structure of the battery housing according to claim 1, characterized in that: The overlapped portion is welded to the end of the shell on the side where the opening is provided to form a welded portion, wherein the welded portion completely covers the joint and extends deep into the convex portion; Along the first direction, a distance between an end of the welding portion facing the cover plate and a peripheral side wall of the protrusion is h2, and a value range of h2 is: 0.6 mm ≤ h2 ≤ 2.0 mm.

3. The assembly structure of the battery housing according to claim 2, characterized in that: Along the second direction, the weld width of the weld is w, and the relationship between w and h2 satisfies: 0.3≤w / h2≤1.8; The value range of w is: 0.5mm≤w≤1.5mm.

4. The assembly structure of the battery housing according to claim 2, characterized in that: The end of the welding portion facing away from the cover plate protrudes from the outer wall of the shell by a dimension C2; The value range of C2 is: 0mm≤C2<0.2mm.

5. The assembly structure of the battery housing according to claim 1, characterized in that: Along the second direction, the total thickness of the cover plate is L1, and the size of the overlap portion is L2; The relationship between L1 and L2 satisfies: 0.16≤L2 / L1≤0.8; The value range of L1 is: 1.5mm≤L1≤3.0mm; The value range of L2 is: 0.5mm≤L2≤2.4mm.

6. The assembly structure of the battery housing according to claim 1, characterized in that: The convex portion includes a guide section and a matching section, the matching section is connected to the body, and the convex portion is installed in the accommodating cavity of the shell under the guidance of the guide section; along the second direction, the size of the matching section is L3; The value range of L3 is: 0.5mm≤L3≤2.4mm.

7. The assembly structure of the battery housing according to claim 6, characterized in that: Along the first direction, there is a gap f between the peripheral side wall of the matching section and the inner wall of the housing, where f=h1+△t1+△t2; Wherein, Δt1 is the machining tolerance of the inner wall of the shell facing the accommodating cavity along the first direction; Δt2 is the machining tolerance of the peripheral side wall of the matching section along the first direction; The value range of △t1 is: -0.1mm≤△t1≤0.1mm; The value range of △t2 is: -0.05mm≤△t1≤0.05mm.

8. The assembly structure of the battery housing according to claim 1, characterized in that: The shell includes two oppositely arranged first side panels and two oppositely arranged second side panels, the first side panels and the second side panels form a cylindrical structure, the openings are formed on opposite sides of the shell along the second direction, the area of ​​the first side panel is larger than the area of ​​the second side panel, and the overlapping portion cooperates with the end of the first side panel along the second direction to form a seam.

9. A battery, characterized in that: An assembly structure comprising a battery casing according to any one of claims 1 to 8.

10. The battery according to claim 9, characterized in that The battery comprises a shell, a positive electrode cover plate and a negative electrode cover plate. The shell is provided with a first opening and a second opening on opposite sides. The positive electrode cover plate and the first opening, and / or the negative electrode cover plate and the second opening are connected by the assembly structure of the battery shell.

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