Battery structure and battery periphery welding process

Abstract

The invention relates to the technical field of batteries, in particular to a battery structure and a battery periphery welding process, the battery structure comprises a shell, the shell is provided with an accommodating cavity with an opening at one end in a first direction, and a cover plate covers the opening. The cover plate comprises a plate body and a limiting edge which are fixedly connected with each other, the limiting edge is arranged on the outer edge of the plate body, and the part, close to the shell, of the plate body can stretch into the containing cavity relative to the limiting edge. When the plate body and the shell are in an assembled state, the distance between the limiting edge and the shell is a in the first direction, and a is larger than or equal to 0 mm and smaller than or equal to 0.3 mm. According to the battery structure and the battery periphery welding process provided by the invention, the phenomena of missing welding, insufficient welding and the like of the welding seam of the shell and the cover plate are greatly reduced. And the yield of laser peripheral welding of the shell and the cover plate exceeds 99.8%.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery structure and a battery peripheral welding process. Background Art

[0002] Traditionally, the connection between the battery shell and the cover plate is usually achieved by spot welding or resistance welding. Although these methods can meet production needs to a certain extent, they are prone to spatter and uneven welds during the welding process, which affects the welding quality. Laser welding technology has gradually become an important welding method in the field of precision welding due to its advantages such as high energy density and small heat-affected zone. Especially in lithium battery manufacturing, laser welding is widely used due to its non-contact, high-precision, and high-speed characteristics.

[0003] With the rapid development of new energy vehicles, energy storage systems and other fields, the demand for high-performance batteries is increasing. Laser peripheral welding technology has broad application prospects in the battery manufacturing industry due to its high efficiency and high quality.

[0004] The laser peripheral welding technology is used to weld the battery shell and the cover plate. The laser beam is irradiated along the edge of the shell and the cover plate, so that the laser quickly melts the metal materials of the shell and the cover plate to achieve a firm connection between the shell and the cover plate. However, the distance between the battery shell and the cover plate becomes a key factor affecting the welding quality of the battery shell and the cover plate. Once the distance between the battery shell and the cover plate is too large, it is very easy for the laser to be difficult to melt the battery shell and the cover plate at the same time, or the melted parts of the battery shell and the cover plate are difficult to contact, resulting in leakage and cold welding of the welds of the shell and the cover plate, resulting in poor welding of the battery shell.

[0005] In addition, even if the distance between the battery shell and the cover plate is too large, the battery shell and the cover plate can be stably welded, but the deformation caused by the welding is large, which can easily cause the explosion-proof valve on the cover plate to fail to open due to deformation. Summary of the invention

[0006] The purpose of the present application is to provide a battery structure and a battery peripheral welding process, so as to solve to a certain extent the technical problem in the prior art that once the distance between the battery shell and the cover plate is too large, it is very easy for the laser to fail to melt the battery shell and the cover plate at the same time, or the melted parts of the battery shell and the cover plate are difficult to contact, resulting in welding leaks, cold welding and the like in the welds between the shell and the cover plate, resulting in poor welding of the battery shell.

[0007] According to a first aspect of the present application, a battery structure is provided, comprising a housing and a cover plate, wherein the housing is provided with a cavity having an opening at one end in a first direction, and the cover plate is sealed on the opening;

[0008] The cover plate comprises a plate body and a limiting edge which are fixedly connected to each other, wherein the limiting edge is arranged at the outer edge of the plate body, and relative to the limiting edge, a portion of the plate body close to the shell can extend into the cavity;

[0009] When the plate body and the shell are in an assembled state, in a first direction, a distance between the limit edge and the shell is a, wherein 0 mm ≤ a ≤ 0.3 mm.

[0010] Preferably, in a direction perpendicular to the first direction, the limit edge protrudes outward relative to the housing;

[0011] The distance b1 between the outer edge of the limiting edge and the outer edge of the shell is 0mm≤b1≤0.3mm.

[0012] Preferably, in a direction perpendicular to the first direction, the limit edge is recessed inwardly relative to the housing;

[0013] The distance b2 between the outer edge of the limiting edge and the outer edge of the shell is 0mm≤b2≤0.3mm.

[0014] According to the second aspect of the present application, a battery peripheral welding process is provided, including the battery structure described in any of the above technical solutions, and thus has all the beneficial technical effects of the battery structure, which will not be repeated here.

[0015] Preferably, the peripheral welding speed of the shell and the cover plate is 140 mm / s to 260 mm / s.

[0016] Preferably, during the laser welding process of the shell and the cover plate, the inner ring power is 600W to 1100W.

[0017] Preferably, during the laser welding process of the shell and the cover plate, the outer ring power is 1500W to 2000W.

[0018] Preferably, the defocus amount of the laser peripheral welding of both the shell and the cover plate is -2.5 mm to 4 mm.

[0019] Preferably, the number of laser peripheral welding on both the shell and the cover plate is less than or equal to 7 times.

[0020] Preferably, before the shell and the cover plate are welded together via the laser peripheral welding process, the shell and the cover plate are fixed via a laser spot welding process.

[0021] Compared with the prior art, the beneficial effects of this application are:

[0022] The battery structure provided by the present application, when 0mm≤a≤0.3mm, can meet the assembly requirements of both the shell and the cover plate, and the shell and the cover plate are stably connected after the laser peripheral welding (that is, the shell and the cover plate can still be stably connected under the internal pressure of 1.2Mpa to ensure the stability of the battery), which greatly reduces the occurrence of leakage welding and cold welding in the welds between the shell and the cover plate. The yield rate of laser peripheral welding of the shell and the cover plate is guaranteed to exceed 99.8%.

[0023] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 A schematic diagram of a cross-sectional structure of a battery structure provided in an embodiment of the present application;

[0026] Figure 2 for Figure 1 The enlarged schematic diagram of the battery structure provided at A;

[0027] Figure 3 Another schematic cross-sectional view of a battery structure provided in an embodiment of the present application;

[0028] Figure 4 for Figure 3 The enlarged schematic diagram of the battery structure provided at B;

[0029] Figure 5 Another schematic cross-sectional view of the battery structure provided in an embodiment of the present application;

[0030] Figure 6 for Figure 5 The enlarged schematic diagram of the battery structure provided is at C;

[0031] Figure 7 This is a schematic diagram of the axonometric structure of the battery structure provided in an embodiment of the present application.

[0032] Reference numerals:

[0033] 1-cover plate; 11-limiting edge; 12-plate body; 2-shell; 21-cavity; 3-explosion-proof valve; F1-first direction. DETAILED DESCRIPTION

[0034] The technical solution of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments.

[0035] The components of the embodiments of the present application generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed, but merely represents the selected embodiments of the present application.

[0036] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of this application.

[0037] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application 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 therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0038] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0039] Refer to the following Figures 1 to 6 The battery structure and the battery peripheral welding process according to some embodiments of the present application are described.

[0040] See also Figures 1 to 6As shown, an embodiment of the first aspect of the present application provides a battery structure, wherein the housing 2 is provided with a cavity 21 having an opening at one end in a first direction F1, and the cover plate 1 covers the opening. The cover plate 1 includes a plate body 12 and a limit edge 11 fixedly connected to each other, the limit edge 11 being provided at the outer edge of the plate body 12, and relative to the limit edge 11, the portion of the plate body 12 close to the housing 2 can extend into the cavity 21. When the plate body 12 and the housing 2 are in an assembled state, in the first direction F1, the spacing between the limit edge 11 and the housing 2 is a, wherein 0mm≤a≤0.3mm.

[0041] Refer to Table 1, which shows the conclusion of the defective rate of welding of the shell 2 and the cover plate 1 obtained by welding with different A values ​​for the same battery setting. It can be seen from the table that when 0mm≤a≤0.3mm, the assembly requirements of both the shell 2 and the cover plate 1 can be met, and the shell 2 and the cover plate 1 are stably connected after the laser peripheral welding (that is, the shell 2 and the cover plate 1 can still be stably connected under the internal pressure of 1.2Mpa to ensure the stability of the battery), which greatly reduces the phenomenon of leaking welding and cold welding between the shell 2 and the cover plate 1. Ensure that the yield rate of laser peripheral welding of the shell 2 and the cover plate 1 exceeds 99.8%.

[0042] Table 1:

[0043]

[0044] Alternatively, if Figure 1 and Figure 2 As shown, in the direction perpendicular to the first direction F1, the outer edge of the above-mentioned limit edge 11 is aligned with the outer edge of the above-mentioned shell 2 (i.e., b=0), which effectively shortens the distance between the docking positions of the shell 2 and the limit edge 11, thereby reducing the incidence of welding defects of both the shell 2 and the limit edge 11, and further ensuring the welding quality of both the shell 2 and the limit edge 11.

[0045] Alternatively, if Figure 3 and Figure 4 As shown, in the direction perpendicular to the first direction F1, the limit edge 11 protrudes outward relative to the shell 2, and the distance b1 between the outer edge of the limit edge 11 and the outer edge of the shell 2 is 0mm≤b1≤0.3mm. In this way, a certain processing tolerance can be provided between the cover plate 1 and the shell 2 to reduce the processing difficulty of both the cover plate 1 and the shell 2.

[0046] Alternatively, if Figure 5 and Figure 6As shown, in the direction perpendicular to the first direction F1, the limit edge 11 is recessed inward relative to the shell 2, and the distance b2 between the outer edge of the limit edge 11 and the outer edge of the shell 2 is 0mm≤b2≤0.3mm. In this way, a certain processing tolerance can be provided between the cover plate 1 and the shell 2 to reduce the processing difficulty of both the cover plate 1 and the shell 2.

[0047] In summary, if the position of the outer edge of the shell 2 is taken as the reference zero point, and the distance from the outer edge of the above-mentioned limiter 11 to the outer edge of the shell 2 is b, then -0.3mm≤b≤0.3mm. That is, 0mm≤b1≤0.3mm can be understood as 0mm<b≤0.3mm, and 0mm≤b2≤0.3mm can be understood as -0.3mm≤b<0mm. As shown in Table 1 above, when -0.3mm≤b≤0.3mm, the assembly requirements of both the shell 2 and the cover plate 1 can be met, and the shell 2 and the cover plate 1 are stably connected after the laser peripheral welding is completed (that is, the welds of the shell 2 and the cover plate 1 can still be stably connected under the internal pressure of 1.2Mpa to ensure the stability of the battery), which greatly reduces the occurrence of leaking welds and cold welds in the welds of the shell 2 and the cover plate 1. Ensure that the yield rate of laser peripheral welding of the shell 2 and the cover plate 1 exceeds 99.8%.

[0048] Alternatively, if Figure 7 As shown, the cover plate 1 may also be provided with an explosion-proof valve 3 .

[0049] like Figure 7 As shown in the figure, the battery structure is an example of a square battery. The first direction F1 can be the length direction of the square battery.

[0050] Preferably, the thickness of the square battery (ie, Figure 7 The T value shown) can be less than or equal to 16 mm to adapt to the size of existing blade batteries.

[0051] The embodiment of the second aspect of the present application also provides a battery peripheral welding process, including the battery structure described in any of the above embodiments, and thus has all the beneficial technical effects of the battery structure, which will not be repeated here.

[0052] Preferably, the housing 2 and the cover plate 1 can be welded and connected via a laser peripheral welding process.

[0053] Preferably, before the shell 2 and the cover plate 1 are welded and connected via the laser peripheral welding process, the shell 2 and the cover plate 1 may also be fixed via a laser spot welding process to ensure the accuracy and stability of the laser peripheral welding.

[0054] Preferably, the peripheral welding speed of the shell 2 and the cover plate 1 can be 140 mm / s to 260 mm / s, as shown in Table 2, which shows an example of laser welding the shell 2 and the cover plate 1 of batteries of the same size and specification at different peripheral welding speeds. In Table 2, when the peripheral welding speed is less than 140 mm / s (for example, the example shown in sequence number 1 in Table 2), the shell 2 and the cover plate 1 are deformed too much after the peripheral welding due to the slow welding speed, resulting in an open valve ratio of the explosion-proof valve 3 on the plate body 12 as high as 0.5%, and the defect rate is too high; when the peripheral welding speed is greater than 260 mm / s (for example, Table 2 2 shows an example), although the deformation of both the shell 2 and the cover plate 1 after the peripheral welding does not cause the explosion-proof valve 3 on the plate body 12 to open, the proportion of welding defects such as pinholes between the shell 2 and the cover plate 1 is as high as 0.83%, and the defect rate is too high; when the peripheral welding speed meets 140mm / s~260mm / s (for example, examples are shown by serial numbers 4~13 in Table 2), the deformation of both the shell 2 and the cover plate 1 after the peripheral welding does not cause the explosion-proof valve 3 on the plate body 12 to open, and no defects such as pinholes appear, the welding defect proportion is lower than 0.1%, and the opening pressure of the explosion-proof valve 3 after the peripheral welding meets the requirements.

[0055] Preferably, during the laser welding process of the shell 2 and the cover plate 1, the inner ring power can be 600W to 1100W to ensure the depth and size of the laser welding of the shell 2 and the cover plate 1. Referring to Table 2, when the inner ring power is less than 600W (for example, the example of serial number 2 shown in Table 2), the shell 2 and the cover plate 1 will have a certain degree of pinhole defects after laser peripheral welding; and when the inner ring power exceeds 1100W (for example, the example of serial number 13 shown in Table 2), after the shell 2 and the cover plate 1 are laser peripherally welded, due to the excessive power capacity, the deformation of the shell 2 and the cover plate 1 will cause the explosion-proof valve 3 to fail and open.

[0056] Preferably, during the laser welding process of the shell 2 and the cover plate 1, the outer ring power can be 1500W to 2000W to ensure the beauty and smoothness of the weld. Referring to Table 2, when the outer ring power is less than 1400W (for example, the example of serial number 2 shown in Table 2), the shell 2 and the cover plate 1 will have a certain degree of pinhole defects after laser peripheral welding; and when the inner ring power exceeds 2000W (for example, the example of serial number 13 shown in Table 2), after the shell 2 and the cover plate 1 are laser peripherally welded, due to the excessive power capacity, the deformation of the shell 2 and the cover plate 1 will cause the explosion-proof valve 3 to fail and open.

[0057] It should be noted that during the laser welding process, the inner ring power and the outer ring power refer to the power at different positions during the continuous scanning of the laser beam. The inner ring refers to the ring where the reflector is fixed, and the outer ring refers to the ring where the reflector is moving.

[0058] Preferably, the defocus amount of laser peripheral welding of the shell 2 and the cover plate 1 can be -2.5mm~4mm, as shown in Table 2. When the defocus amount is less than -2.5mm (for example, the example of serial number 3 shown in Table 2), the deformation of both the shell 2 and the cover plate 1 will cause the explosion-proof valve 3 to fail and open; when the defocus amount is greater than 4mm (for example, the example of serial number 16 shown in Table 2), a certain degree of pinhole defects will appear on both the shell 2 and the cover plate 1 after laser peripheral welding.

[0059] Preferably, as shown in Table 2, the number of laser peripheral welding of the shell 2 and the cover plate 1 can be less than or equal to 7 times. When the number of laser peripheral welding of the shell 2 and the cover plate 1 is greater than 7 times (for example, the example of serial number 11 shown in Table 2), the edge deformation of the cover plate 1 is large and it is not recommended to use.

[0060] Table 2:

[0061]

[0062]

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A battery structure, characterized in that: It comprises a shell and a cover plate, wherein the shell is provided with a cavity having an opening at one end in a first direction, and the cover plate is sealed on the opening; The cover plate comprises a plate body and a limiting edge which are fixedly connected to each other, wherein the limiting edge is arranged at the outer edge of the plate body, and relative to the limiting edge, a portion of the plate body close to the shell can extend into the cavity; When the plate body and the shell are in an assembled state, in a first direction, a distance between the limit edge and the shell is a, wherein 0 mm ≤ a ≤ 0.3 mm.

2. The battery structure according to claim 1, characterized in that: In a direction perpendicular to the first direction, the limit edge protrudes outward relative to the shell; The distance b1 between the outer edge of the limiting edge and the outer edge of the shell is 0mm≤b1≤0.3mm.

3. The battery structure according to claim 2, characterized in that: In a direction perpendicular to the first direction, the limit edge is recessed inwardly relative to the shell; The distance b between the outer edge of the limiting edge and the outer edge of the shell is 0mm≤b2≤0.3mm.

4. A battery peripheral welding process, characterized in that: The battery structure comprises the battery structure according to any one of claims 1 to 3, wherein the shell and the cover plate are welded and connected via a laser peripheral welding process.

5. The battery peripheral welding process according to claim 4, characterized in that: The peripheral welding speed of the shell and the cover plate is 140 mm / s to 260 mm / s.

6. The battery peripheral welding process according to claim 4, characterized in that: During the laser welding process of the shell and the cover plate, the inner ring power is 600W to 1100W.

7. The battery peripheral welding process according to claim 6, characterized in that: During the laser welding process of the shell and the cover plate, the outer ring power is 1500W to 2000W.

8. The battery peripheral welding process according to claim 4, characterized in that: The defocus amount of the laser peripheral welding of both the shell and the cover plate is -2.5 mm to 4 mm.

9. The battery peripheral welding process according to claim 4, characterized in that: The number of laser peripheral welding on both the shell and the cover plate is less than or equal to 7 times.

10. The battery peripheral welding process according to claim 4, characterized in that: Before the shell and the cover are welded together via the laser peripheral welding process, the shell and the cover are fixed via the laser spot welding process.

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