End cover assembly for battery and power battery

Abstract

The utility model relates to an end cover assembly for a battery and a power battery. The end cover assembly comprises a cover plate, a first sealing piece and a second sealing piece, and a liquid injection hole is formed in the cover plate; the liquid injection hole comprises a first hole section and a second hole section communicated with the first hole section; the first sealing piece is welded to the first hole section; the second sealing piece is hermetically connected to the second hole section; at least one of the first sealing piece and the cover plate is provided with a stress releasing part used for releasing welding stress. The second sealing piece is matched with the second hole section, the first sealing piece is welded and matched with the first hole section, double sealing is achieved, and therefore the sealing effect on the liquid injection hole is improved. Meanwhile, at least one of the first sealing piece and the cover plate is provided with a stress release part, so that stress near a welding seam is released, the welding seam is prevented from generating cracks, the connecting effect of the first sealing piece and the first hole section is further guaranteed, the sealing performance of the liquid injection hole is improved, the liquid leakage possibility is reduced, and potential safety hazards are reduced.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to an end cover assembly for a battery and a power battery. Background Art

[0002] With the development of modern society and the enhancement of people's environmental awareness, more and more devices choose lithium batteries as power sources, such as mobile phones, laptops, power tools and electric vehicles, etc., which provides a broad space for the application and development of lithium batteries. Among them, lithium batteries used in power tools and electric vehicles are generally called power batteries.

[0003] Power batteries generally include a battery cell, a battery case that contains the battery cell, an end cap assembly sealed on the battery case, and electrolyte poured into the battery case. In order to facilitate the injection of electrolyte into the battery case, an injection hole is usually opened on the cover plate of the end cap assembly. When the injection is completed, the injection hole needs to be closed.

[0004] In the related art, the sealing effect of the injection hole is poor, which may easily cause leakage and pose a safety hazard. Utility Model Content

[0005] Based on this, it is necessary to provide an end cover assembly for a battery to address the problem of poor sealing effect of the liquid injection hole in the power battery.

[0006] An end cap assembly for a battery, the end cap assembly for the battery comprising:

[0007] A cover plate, wherein the cover plate is provided with a liquid injection hole; the liquid injection hole comprises a first hole segment and a second hole segment connected with the first hole segment;

[0008] a first sealing member, the first sealing member being welded to the first hole section;

[0009] a second sealing member, the second sealing member being sealingly connected to the second bore section;

[0010] Wherein, at least one of the first sealing member and the cover plate is provided with a stress release portion for releasing welding stress.

[0011] In one embodiment, the stress relief portion includes an annular groove disposed on the cover plate and / or the first sealing member.

[0012] In one of the embodiments, the stress release portion includes a plurality of first grooves spaced apart along the circumference of the injection hole; the first grooves are located on the cover plate and / or the first sealing member.

[0013] In one embodiment, the first sealing member includes a first sealing layer, a second sealing layer and a third sealing layer distributed along the axial direction of the injection hole; and the stress release portion is at least arranged on the first sealing layer.

[0014] In one embodiment, the central axis of the first hole segment is not colinear with the central axis of the second hole segment.

[0015] In one embodiment, the outer peripheral surface of the first seal is provided with an external thread; the inner wall of the first hole section is provided with an internal thread matching with the external thread; and the thread matching gap between the first seal and the first hole section is used to accommodate solder.

[0016] In one embodiment, the first sealing member is provided with a first protrusion; the first protrusion abuts against the bottom wall of the first hole section; and / or

[0017] The cover plate is provided with a second groove, and the second groove is located on the outer side of the second hole section along its radial direction; the second sealing member is provided with a second protrusion for engaging with the second groove.

[0018] In one embodiment, along the axial direction of the injection hole and along the direction from the first sealing member to the second sealing member, the cross-sectional area of ​​the first sealing member gradually decreases; and / or

[0019] Along the axial direction of the injection hole and along the direction from the first sealing member to the second sealing member, the aperture of the first hole section gradually decreases.

[0020] In one embodiment, one end of the second sealing member facing the second hole section is a tapered structure.

[0021] A power battery, comprising a housing, a battery cell and the end cover assembly for the battery as described above;

[0022] The housing is provided with a receiving cavity, and the receiving cavity has an opening;

[0023] The battery cell is arranged in the accommodating cavity, and the end cover assembly for the battery is connected to the shell to cover the opening.

[0024] The end cap assembly for the battery includes a cover plate, a first seal and a second seal. The second seal cooperates with the second hole segment, and the first seal cooperates with the first hole segment by welding, so as to achieve double sealing, thereby improving the sealing effect of the injection hole. At the same time, by providing a stress release portion on at least one of the first seal and the cover plate, the stress near the weld is released to prevent cracks in the weld, further ensure the connection effect of the first seal and the first hole segment, and then improve the sealing performance of the injection hole, reduce the possibility of leakage, and reduce safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of an end cover assembly for a battery provided in accordance with the first embodiment of the present application.

[0026] Figure 2 for Figure 1 A partial enlarged view of A in the end cap assembly for a battery is shown.

[0027] Figure 3 for Figure 1 An exploded partial view of an end cap assembly for a battery is shown.

[0028] Figure 4 for Figure 3 A schematic diagram of a liquid injection hole and a first sealing member in an end cover assembly for a battery is shown.

[0029] Figure 5 A schematic diagram of a first seal in an end cover assembly for a battery provided in the second embodiment of the present application.

[0030] Figure 6 A schematic diagram of a first seal in an end cover assembly for a battery provided in the third embodiment of the present application.

[0031] Figure 7 A schematic diagram of a liquid injection hole and a second sealing member in an end cover assembly for a battery provided in the fourth embodiment of the present application.

[0032] Figure numbers: 100, end cover assembly for battery; 110, cover plate; 111, first hole section; 112, second hole section; 113, stress release portion; 114, annular groove; 115, second groove; 120, first sealing member; 121, first groove; 122, first sealing layer; 123, second sealing layer; 124, third sealing layer; 125, first protrusion; 130, second sealing member; 131, second protrusion; 132, tapered structure. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0034] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply 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 a limitation on the present application.

[0035] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0036] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0037] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0038] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0039] During the assembly process of the battery, it is necessary to open a liquid injection hole on the cover plate of the battery so as to inject electrolyte into the battery. When the injection is completed, the liquid injection hole needs to be closed. In the prior art, the liquid injection hole has the problem of poor sealing effect, which is easy to cause leakage and poses a safety hazard. The purpose of the setting of the present application is to improve the sealing performance of the liquid injection hole and prevent sealing failure. The end cover assembly for the battery provided in one embodiment of the present application will be introduced in detail below in conjunction with the accompanying drawings.

[0040] See also Figures 2 to 4 As shown, an end cap assembly 100 for a battery provided in an embodiment of the present application includes a cover plate 110, a first seal 120 and a second seal 130, wherein the cover plate 110 is provided with a liquid injection hole; the liquid injection hole includes a first hole section 111 and a second hole section 112 connected to the first hole section 111; the first seal 120 is welded to the first hole section 111; the second seal 130 is sealed and connected to the second hole section 112; wherein at least one of the first seal 120 and the cover plate 110 is provided with a stress release portion 113 for releasing welding stress. That is to say, the stress release portion 113 can be provided only on the first seal 120, or only on the cover plate 110; of course, the stress release portion 113 can also be provided on both the first seal 120 and the cover plate 110.

[0041] Specifically, the second seal 130 cooperates with the second hole section 112, and the first seal 120 cooperates with the first hole section 111 by welding, so as to achieve double sealing, thereby improving the sealing effect of the injection hole. At the same time, by setting a stress release portion 113 on at least one of the first seal 120 and the cover plate 110, the stress near the weld is released to prevent cracks in the weld, further ensuring the connection effect of the first seal 120 and the first hole section 111, thereby improving the sealing performance of the injection hole, reducing the possibility of leakage, and reducing safety hazards. Among them, the first seal 120 can be made of aluminum, and the second seal 130 can be made of rubber.

[0042] See also Figures 2 to 4As shown, in one embodiment, the stress release portion 113 includes an annular groove 114 provided on the cover plate 110 and the first sealing member 120. The annular groove 114 is used to release stress near the weld, thereby ensuring the welding sealing effect of the first sealing member 120 and the cover plate 110 and reducing the possibility of leakage. Figure 5 As shown, in other embodiments, the stress release portion 113 may also include a plurality of first grooves 121 arranged on the first sealing member 120 and spaced apart along the circumference of the injection hole. Stress release is achieved through the plurality of first grooves 121. Further, the stress release portion 113 arranged on the cover plate 110 may also be a plurality of grooves spaced apart along the circumference.

[0043] See also Figure 4 As shown, in some embodiments, the height of the first seal 120 can be less than or equal to the depth of the first hole section 111. Through this arrangement, the first seal 120 can be completely accommodated in the first hole section 111 and will not protrude from the surface of the cover plate 110, thereby preventing the first seal 120 from being bumped, thereby avoiding the problem of sealing failure caused by bumping and displacement of the first seal 120, and improving the service life of the first seal 120 and the sealing performance of the end cover assembly.

[0044] See also Figure 4 As shown, in some embodiments, the aperture of the first hole section 111 can be slightly larger than the diameter of the first seal 120. Through this arrangement, on the one hand, it is convenient to install the first seal 120 in the first hole section 111; on the other hand, when welding the first seal 120 and the cover plate 110, the gap between the first hole section 111 and the first seal 120 can be used to accommodate solder. Specifically, it is convenient for the welding gun to extend into the gap during welding without interfering with other components, which facilitates the injection of solder. At the same time, the solder can accumulate in the gap without protruding outside the cover plate 110, which improves the flatness of the end cover assembly and is conducive to achieving profit release.

[0045] See also Figure 6As shown, in one embodiment, the first sealing member 120 includes a first sealing layer 122, a second sealing layer 123 and a third sealing layer 124 distributed along the axial direction of the injection hole; the stress release portion 113 is at least arranged in the first sealing layer 122. Specifically, the first sealing layer 122 and the third sealing layer 124 are both aluminum layers, the second sealing layer 123 located between the first sealing layer 122 and the second sealing layer 123 is a magnesium layer, and the stress release portion 113 runs through the first sealing layer 122 and the second sealing layer 123. In other words, the first sealing member 120 is machined from a magnesium-aluminum composite plate, and the middle magnesium layer gives the stress release portion 113 excellent strength, ensuring that the stress release portion 113 has a certain thickness, so that the welding residual stress can be better released, crystal cracks are not easily generated, and safety problems such as leakage caused by weld cracking are reduced. The middle layer is provided with a magnesium plate. Since the strength of magnesium is better than that of aluminum, the addition of a magnesium layer can improve the strength of the first sealing member 120, so that during the charge and discharge cycle, the stress release portion 113 will not be cracked due to its thin thickness, thereby preventing electrolyte leakage. The first sealing layer 122 and the third sealing layer 124 are made of aluminum, which has good corrosion resistance, and prevents the electrolyte from corroding the first sealing member 120 and leaking.

[0046] See also Figures 2 to 4 As shown, in some embodiments, the first hole segment 111 is a cylindrical hole, and the first seal 120 is a body of revolution, that is, the central axis of the first seal 120 coincides with the central axis of the first hole segment 111, and the two are coaxially arranged. In this way, the gap width between the first seal 120 and the first hole segment 111 can be distributed more evenly along the circumferential direction, ensuring the uniformity of solder injection, and then ensuring the consistency of the stability after welding at each position, avoiding the partial sealing failure caused by the uneven welding force on the first seal 120 when the internal pressure of the battery is too high. Specifically, the first seal 120 can be a truncated cone plug.

[0047] In one embodiment, the outer peripheral surface of the first sealing member 120 is provided with an external thread (not shown); the inner wall of the first hole section 111 is provided with an internal thread (not shown) matching with the external thread; and the thread matching gap between the first sealing member 120 and the first hole section 111 is used to accommodate solder.

[0048] Specifically, if the first seal and the first hole section are threaded, during installation, the first seal can be screwed into the first hole section first, so as to improve the connection stability between the first seal and the end cover by threaded connection. Then the first seal and the cover plate are welded together by welding. By combining welding and threaded connection, the connection stability and connection effect between the first seal and the cover plate are further improved, and the sealing performance is enhanced.

[0049] Optionally, when the first seal is connected to the cover plate by welding, at least part of the first seal can be used to form solder. Specifically, the first seal can be connected to the cover plate by welding by melting part of the first seal, that is, the first seal is fusion-welded to the cover plate.

[0050] In other embodiments, there may be a gap between the first sealing member and the cover plate, and the gap is used to accommodate solder to form a weld to improve the connection firmness between the first sealing member and the cover plate. It can be seen that the solder can be achieved by melting the sealing member itself or by adding it externally, and the source of solder and welding methods are more diverse.

[0051] See also Figure 4 As shown, in one embodiment, the first sealing member 120 is provided with a first protrusion 125; the first protrusion 125 abuts against the bottom wall of the first hole section 111. With this arrangement, when the first sealing member 120 is installed in the first hole section 111, there will be no interference with the second sealing member 130, thereby ensuring the sealing effect of the first sealing member 120 and the second sealing member 130 on the injection hole.

[0052] See also Figure 7 As shown, in one embodiment, a second groove 115 is provided on the cover plate 110 , and the second groove 115 is located on the radial outer side of the second hole section 112 ; a second protrusion 131 for engaging with the second groove 115 is provided on the second sealing member 130 .

[0053] Specifically, the second seal 130 and the cover plate 110 are snap-fitted and positioned by the second protrusion 131 and the second groove 115, so that the fixation of the second seal 130 is more stable and reliable, and the second seal 130 can be effectively prevented from falling into the battery; in addition, the contact area between the second seal 130 and the cover plate 110 is increased, the probability of the second seal 130 moving in the injection hole is reduced, and the sealing effect is improved. Among them, the second protrusion 131 and the second seal 130 are made of the same material, and the second protrusion 131 and the second seal 130 can be integrally formed. The integral molding processing method makes the connection between the second protrusion 131 and the second seal 130 more stable and easier to process.

[0054] See also Figure 4As shown, in one embodiment, along the axial direction of the injection hole and along the direction from the first sealing member 120 to the second sealing member 130, the cross-sectional area of ​​the first sealing member 120 gradually decreases. That is, the outer peripheral surface of the first sealing member 120 is a conical surface; similarly, the inner wall of the first hole section 111 matched with the first sealing member 120 is also a conical surface, that is, the aperture of the first hole section 111 gradually decreases, so that the cooperation between the first sealing member 120 and the first hole section 111 can be more stable.

[0055] See also Figure 7 As shown, in one embodiment, one end of the second seal 130 facing the second hole section 112 is a tapered structure 132. That is, along the direction from the first seal 120 to the second seal 130, the cross-sectional area of ​​the bottom of the second seal 130 gradually decreases. Through this arrangement, the second seal 130 is easier to install in the second hole section 112, and the fit between the second seal 130 and the second hole section 112 can be more stable. Among them, the second seal 130 and the second hole section 112 are interference fit, and the interference fit makes the sealing effect of the second seal 130 better, and at the same time provides a force for the fixation of the second seal 130.

[0056] In one embodiment, the central axis of the first hole segment is not colinear with the central axis of the second hole segment. That is, the second hole segment deviates from the center of the first hole segment. In this way, when laser welding is performed, the starting point of the laser can be set at a position far away from the second hole segment. In the process of the laser gradually approaching the second hole segment from the starting position, the electrolyte crystals near the second hole segment are gradually vaporized and released, so that the temperature in the second hole segment area gradually decreases, and the corresponding gas release is also reduced, so that only a very small amount of gas is generated during the welding process, the welding rate and welding quality are greatly improved, and the sealing effect of the injection hole can be improved.

[0057] Furthermore, an embodiment of the present application also provides a power battery (not shown), comprising a shell, a battery cell, and the end cap assembly 100 for the battery as described above; the shell is provided with a receiving cavity, and the receiving cavity has an opening formed on at least one side of the shell, such as a single-side opening, or openings are provided on both opposite sides. The battery cell is arranged in the receiving cavity, and the end cap assembly 100 for the battery is connected to the shell to cover the opening. Since the power battery includes the end cap assembly 100 of the above embodiment, it can improve the sealing performance of the injection hole, reduce the possibility of leakage, and reduce safety hazards.

[0058] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0059] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. An end cap assembly for a battery, characterized in that: The end cap assembly for a battery comprises: A cover plate (110), the cover plate (110) being provided with a liquid injection hole; the liquid injection hole comprising a first hole section (111) and a second hole section (112) communicating with the first hole section (111); A first sealing member (120), the first sealing member (120) being welded to the first hole section (111); A second sealing member (130), the second sealing member (130) being sealingly connected to the second hole section (112); Wherein, at least one of the first sealing member (120) and the cover plate (110) is provided with a stress release portion (113) for releasing welding stress.

2. The end cap assembly for a battery according to claim 1, characterized in that: The stress release portion (113) comprises an annular groove (114) arranged on the cover plate (110) and / or the first sealing member (120).

3. The end cap assembly for a battery according to claim 1, characterized in that: The stress release portion (113) comprises a plurality of first grooves (121) spaced apart along the circumference of the injection hole; the first grooves (121) are located on the cover plate (110) and / or the first sealing member (120).

4. The end cap assembly for a battery according to claim 1, characterized in that: The first sealing component (120) comprises a first sealing layer (122), a second sealing layer (123) and a third sealing layer (124) distributed along the axial direction of the injection hole; the stress release portion (113) is at least arranged on the first sealing layer (122).

5. The end cap assembly for a battery according to claim 1, characterized in that: The central axis of the first hole section (111) and the central axis of the second hole section (112) are not colinear.

6. The end cap assembly for a battery according to claim 1, characterized in that: The outer peripheral surface of the first sealing member (120) is provided with an external thread; the inner wall of the first hole section (111) is provided with an internal thread matching the external thread; and the thread matching gap between the first sealing member (120) and the first hole section (111) is used to accommodate solder.

7. The end cap assembly for a battery according to claim 1, characterized in that: The first sealing member (120) is provided with a first protruding portion (125); the first protruding portion (125) abuts against the bottom wall of the first hole section (111); and / or The cover plate (110) is provided with a second groove (115), the second groove (115) being located radially outside the second hole section (112); and the second sealing member (130) is provided with a second protrusion (131) for engaging with the second groove (115).

8. The end cap assembly for a battery according to claim 1, characterized in that: Along the axial direction of the injection hole and in the direction from the first sealing member (120) to the second sealing member (130), the cross-sectional area of ​​the first sealing member (120) gradually decreases; and / or Along the axial direction of the injection hole and along the direction from the first sealing member (120) to the second sealing member (130), the aperture of the first hole section (111) gradually decreases.

9. The end cap assembly for a battery according to claim 1, characterized in that: One end of the second sealing member (130) facing the second hole section (112) is a tapered structure (132).

10. A power battery, characterized in that: It comprises a shell, a battery cell and an end cap assembly for a battery as claimed in any one of claims 1 to 9; The housing is provided with a receiving cavity, and the receiving cavity has an opening; The battery cell is arranged in the accommodating cavity, and the end cover assembly for the battery is connected to the shell to cover the opening.

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