Secondary battery and electronic device

Abstract

The utility model provides a secondary battery and electronic equipment, the secondary battery comprises a shell, a pole and an adapter piece, the shell is provided with a pole hole, the pole comprises a connecting part and an outer flange part, the outer flange part and the connecting part seal a clamping end wall to fix the pole, the connecting part comprises a welding part, the welding part is welded with the adapter piece, and the adapter piece is connected with the pole hole. The density of the welding part is larger than that of the outer flange part, so that the density of the welding part is large, crystal grains of the welding part are fine, the fine crystal grains contain more metal atoms, the size of the crystal grains in a molten pool formed by welding is smaller, the quality is more uniform, and then the welding strength can be improved; and it is ensured that the welding strength after the welding part and the switching piece are welded can meet the actual requirement.

Description

Technical Field

[0001] This application relates to the field of energy storage technology, and more particularly to a secondary battery and electronic device. Background Technology

[0002] Currently, most cylindrical battery terminals are machined. However, machined terminals have a drawback: the overall density of different parts of the terminal is lower, resulting in a lower density of the molten pool after welding with the adapter plate. This makes it difficult for the molten pool to meet practical requirements, and consequently, the weld strength is also insufficient. Furthermore, machining is costly, hindering large-scale application. Utility Model Content

[0003] In view of this, the purpose of this application is to provide a secondary battery and electronic device to solve or partially solve the problems raised in the prior art.

[0004] To achieve the above objectives, the first aspect of this application provides a secondary battery, comprising:

[0005] The housing includes an end wall and a side wall surrounding the end wall, and the end wall is provided with a pole post hole;

[0006] The pole includes an outer flange portion disposed on the outside of the housing and a connecting portion connected to the outer flange portion and passing through the pole hole. The outer flange portion and the connecting portion seal and clamp the end wall to fix the pole. The connecting portion includes a welded portion, and the density of the welded portion is greater than the density of the outer flange portion.

[0007] The adapter plate is located inside the housing and is welded to the welding part.

[0008] Optionally, the density of the welded part is greater than or equal to 2.7 g / cm³. 3 And / or the density of the outer flange is greater than or equal to 2.6 g / cm³. 3 .

[0009] Optionally, the connecting part further includes a main body located within the pole post hole. The welded part is integrally formed with the main body, and the density difference between the welded part and the main body is less than 0.1 g / cm³. 3 .

[0010] Optionally, the density of the main body gradually decreases along the direction from the welded portion to the outward flange portion.

[0011] Optionally, the connecting portion further includes an inner flange portion, which is located inside the housing and riveted to the housing. The end of the inner flange portion that connects to the main body portion is the connecting end, and the density of the connecting end is greater than the density of other parts of the inner flange portion except for the connecting end.

[0012] Optionally, the density of the welded part is greater than the density of the adapter piece, and the ratio of the difference between the density of the welded part and the density of the adapter piece to the density of the adapter piece is less than or equal to 10%.

[0013] Optionally, the adapter plate includes a protrusion, which is welded to a welding portion. The inner walls of the welding portion and the inner flange portion together define a first space for accommodating the protrusion.

[0014] Optionally, it also includes a sealing pin, wherein the welded portion, together with the inner wall of the main body and the outer flange portion, defines a second space for accommodating the sealing pin, which is connected to the pole post.

[0015] Optionally, the hardness range of the welded part is 150HV to 250HV, and the thickness of the welded part is greater than or equal to 0.7mm.

[0016] The second aspect of this application provides an electronic device including a secondary battery according to any one of the first aspects described above.

[0017] As can be seen from the above, the secondary battery and electronic device provided in this application include a housing, a terminal post, and an adapter plate. The end wall of the housing is provided with a terminal post hole. The terminal post includes a connecting part and an outer flange part. The outer flange part and the connecting part seal and clamp the end wall to fix the terminal post. The connecting part includes a welding part. The welding part is welded to the adapter plate. The density of the welding part is greater than the density of the outer flange part. Thus, the density of the welding part is larger, and its grains are finer. The fine grains contain more metal atoms. Therefore, the grain size in the weld pool formed by welding is also smaller and the quality is more uniform. This can improve the welding strength and ensure that the welding strength after the welding part is welded to the adapter plate can meet the actual requirements. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A cross-sectional schematic diagram of a secondary battery according to an embodiment of this application is shown;

[0020] Figure 2 A cross-sectional schematic diagram of the pole post according to an embodiment of this application is shown;

[0021] Figure 3 This invention provides a schematic cross-sectional view of the pole before it is folded in accordance with an embodiment of this application.

[0022] Figure 4This invention provides a schematic cross-sectional view of the pole post and sealing nail after connection according to an embodiment of the present application.

[0023] In the figure: 1. Shell; 11. End wall; 12. Side wall; 2. Pole post; 21. Outer flange; 22. Connecting part; 221. Welding part; 222. Main body; 223. Inner flange; 2231. Connecting end; 3. Adapter piece; 31. Pole lug welding part; 32. Protrusion; 4. First space; 5. Sealing pin; 6. Second space; 7. Sealing ring. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0025] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0026] Lithium-ion batteries are among the most widely used rechargeable batteries. They are widely used in electronics, communications, aerospace, and other fields. For cylindrical batteries, the conventional design places the first and second tabs at opposite ends of the cell. Taking the first tab as the positive tab and the second tab as the negative tab as an example, the positive tab is connected to a positive adapter plate, and the negative tab is connected to a negative adapter plate.

[0027] In actual assembly, the shell is usually welded to the terminal post first. Then, the two ends of the electrode assembly are welded to the positive and negative terminal adapters respectively to form a whole. This whole is installed into the shell, so that the positive terminal adapter contacts the part of the terminal post that extends into the shell. Then, the two are laser welded to achieve the welding of the shell, terminal post, positive terminal adapter, electrode assembly and negative terminal adapter. Then, the negative terminal adapter is welded to the cover plate, and the cover plate is also welded to the shell. Finally, the assembly of the entire cylindrical cell is completed.

[0028] Throughout the process, the welding quality and strength of the electrode post and the positive electrode adapter are very important, and the quality and manufacturing process of the electrode post have a huge impact on the welding quality and strength of the electrode post and the positive electrode adapter.

[0029] Currently, most electrode posts are machined. However, machined electrode posts have a drawback: the overall density of different parts of the electrode post is lower, resulting in a lower density of the molten pool after welding with the adapter plate. This makes it difficult for the strength of the molten pool to meet actual requirements, and consequently, the weld strength after welding is also insufficient. In addition, machining is more expensive, which is not conducive to large-scale use.

[0030] Therefore, how to increase the welding strength between the pole and the adapter plate is an urgent problem to be solved.

[0031] Based on this, this application provides a secondary battery.

[0032] Figure 1 A cross-sectional schematic diagram of a secondary battery according to an embodiment of this application is shown. Figure 2 A cross-sectional schematic diagram of the pole post 2 according to an embodiment of this application is shown.

[0033] See Figure 1 and Figure 2 As shown, the secondary battery provided in this application includes:

[0034] The housing 1 includes an end wall 11 and a side wall 12 surrounding the end wall 11, and the end wall 11 is provided with a pole hole;

[0035] The pole post 2 includes an outer flange portion 21 disposed on the outside of the housing 1 and a connecting portion 22 connected to the outer flange portion 21 and passing through the pole post hole. The outer flange portion 21 and the connecting portion 22 seal and clamp the end wall 11 to fix the pole post 2. The connecting portion 22 includes a welding portion 221, and the density of the welding portion 221 is greater than the density of the outer flange portion 21.

[0036] The adapter piece 3 is located inside the housing 1 and is welded to the welding part 221.

[0037] Specifically, the end wall 11 of the housing 1 is provided with a pole hole, the outer flange 21 of the pole 2 is located outside the housing 1, the connecting part 22 of the pole 2 passes through the pole hole, and the connecting part 22 can be partially located inside the housing 1, partially located outside the housing 1, or the connecting part 22 can be entirely located inside the housing 1.

[0038] The outer flange 21 and the connecting portion 22 seal the clamping end wall 11 to fix the pole post 2. The outer flange 21 and the connecting portion 22 are sealed to the housing, and the sealing connection between them is achieved by the sealing ring 7.

[0039] The connecting part 22 includes a welding part 221, which is welded to the adapter piece 3. Specifically, the welding part 221 can extend along a plane perpendicular to the central axis of the housing 1 to increase the contact area with the adapter piece 3 and improve the welding strength between the welding part 221 and the adapter piece 3.

[0040] The density of the welded part 221 is greater than that of the outer flange part 21. As a result, the welded part 221 has a higher density and finer grains. The finer grains contain more metal atoms, so the grain size in the weld pool is also smaller and the quality is more uniform. This can improve the welding strength and ensure that the welding strength of the welded part 221 and the adapter piece 3 can meet the actual requirements.

[0041] In practice, the cold heading process can be used to prepare the pole post 2. The cold heading process utilizes the plastic deformation of metal under external force and, with the help of a mold, redistributes and transfers the metal volume to form the pole post 2 of the required specific shape and size.

[0042] Furthermore, the cold heading stroke can be controlled by adjusting the size of the mold and the applied external force, thereby ensuring that the density of the welded portion 221 of the prepared pole post 2 is greater than that of the outer flange portion 21. Moreover, compared to existing machining methods, using cold heading to prepare the pole post 2 can save on manufacturing costs and facilitate large-scale application.

[0043] In some embodiments, the density of the welded portion 221 is greater than or equal to 2.7 g / cm³. 3 And / or the density of the outer flange 21 is greater than or equal to 2.6 g / cm³. 3 .

[0044] Specifically, when the density of the welded part 221 is greater than or equal to 2.7 g / cm³ 3 At this time, the density of the welded part 221 is relatively high, which can significantly improve the welding strength of the weld pool formed by welding and ensure the welding quality between the welded part 221 and the adapter piece 3.

[0045] When the density of welded part 221 is less than 2.7 g / cm³ 3 At that time, the density of the welded part 221 is relatively small, which cannot effectively improve the welding strength of the weld pool formed by welding, resulting in poor welding quality between the welded part 221 and the adapter piece 3.

[0046] When the battery is in actual use, the gas generated inside the battery will cause the casing 1 to bulge outward. The bulging casing 1 will exert a certain pushing force on the outer flange 21 of the terminal post 2, which may cause the outer flange 21 to deform. If the outer flange 21 is deformed, the sealing between the outer flange 21 and the casing 1 may become worse, which will lead to a poorer sealing effect of the battery and a poorer safety of the battery.

[0047] Therefore, in this application, the density of the outer flange portion 21 is controlled to be greater than or equal to 2.6 g / cm³. 3 This ensures that the outer flange 21 has a high structural strength to meet actual needs. In this way, when the battery is in actual use, the gas generated inside the battery causes the casing 1 to bulge outward. Even if the bulging casing 1 exerts a certain thrust on the outer flange 21, the outer flange 21 with a high structural strength will not deform, which can ensure the sealing effect between the terminal post 2 and the casing 1 and improve the safety of battery use.

[0048] In this embodiment, the pole post 2 can be prepared by cold heading process. Furthermore, the cold heading stroke can be controlled by controlling the size of the mold and the magnitude of the applied external force, thereby controlling the density of the welded part 221 and the outer flange part 21 in the prepared pole post 2. This ensures that the density of the welded part 221 and the outer flange part 21 meets the actual requirements, which can ensure both the welding strength and the structural strength of the outer flange part 21, and prevent the pole post 2 from deforming.

[0049] In some embodiments, the connecting portion 22 further includes a main body portion 222, which is located within the pole post hole. The welding portion 221 is integrally formed with the main body portion, and the density difference between the welding portion 221 and the main body portion 222 is less than 0.1 g / cm³. 3 .

[0050] Specifically, the density difference between the welded portion 221 and the main body 222 is less than 0.1 g / cm³. 3 This ensures that the density difference between the welded part 221 and the main body 222 is small, so that the density difference between the two connected positions will not be too large, and there will be no sudden change in density. This ensures the fatigue resistance of the connection part and avoids deformation or breakage of the main body 222 or the connecting part 22.

[0051] If the density difference between the welded part 221 and the main body 222 is greater than or equal to 0.1 g / cm³ 3 At this time, there is a large difference between the density of the welded part 221 and the density of the main body 222. The density between the two connected parts will change abruptly, resulting in poor fatigue resistance of the connection part. It is very easy for the main body 222 or the connection part 22 to deform or break.

[0052] In some embodiments, along the direction from the weld portion 221 to the outer flange portion 21 (i.e. Figure 2 (As shown in direction A in the diagram), the density of the main body 222 gradually decreases.

[0053] Specifically, along the direction from the welded portion 221 to the outer flange portion 21, the density of the main body portion 222 gradually decreases. That is, the density at the connection between the main body portion 222 and the welded portion 221 is higher, while the density at the connection between the main body portion 222 and the outer flange portion 21 is lower. This ensures that the density difference between the connection points of the main body portion 222 and the welded portion 221 is not too large, and also ensures that the density difference between the connection points of the main body portion 222 and the outer flange portion 21 is not too large. This improves the fatigue resistance between the two connection points and avoids problems such as deformation or breakage of the connection points due to large density differences.

[0054] At the same time, the density of the main body 222 gradually decreases, which can ensure that the density difference between adjacent parts of the main body 222 is not large, improve the overall fatigue resistance of the main body 222, and avoid the problem of sudden density change between adjacent parts of the main body 222, which could lead to deformation or breakage of the main body 222.

[0055] Figure 3 A schematic cross-sectional view of the pole post 2 before it is folded in an embodiment of this application is shown.

[0056] In some embodiments, the connecting portion 22 further includes an inner flange portion 223, which is located inside the housing 1 and riveted to the housing 1. The end of the inner flange portion 223 that connects to the main body portion 222 is a connecting end 2231, and the density of the connecting end 2231 is greater than the density of other parts of the inner flange portion 223 except for the connecting end 2231.

[0057] Specifically, the density of the connecting end 2231 is greater than the density of the other parts of the inner flange portion 223 besides the connecting end 2231. That is, in the inner flange portion 223, the density of the connecting end 2231 connected to the main body portion 222 is the highest, while the density of the rest is lower. Thus, in a practical implementation, the unfolded pole post 2 (such as...) Figure 3 The connecting portion 22 (as shown) is folded to form an inner flange 223, so that the connecting end 2231 with the highest density can serve as a fulcrum for folding during the riveting process of the inner flange 223 and the housing 1. Because the connecting end 2231 has a high density, the structural strength of the connecting portion 22 during the folding process can be ensured, and the connecting portion 22 can be prevented from deforming or breaking due to insufficient structural strength caused by too low density.

[0058] In some embodiments, the density of the welded portion 221 is greater than the density of the adapter piece 3, and the ratio of the difference between the density of the welded portion 221 and the density of the adapter piece 3 to the density of the adapter piece 3 is less than or equal to 10%.

[0059] Specifically, when the ratio of the density difference between the welded part 221 and the density of the adapter piece 3 to the density of the adapter piece 3 is less than or equal to 10%, the density difference between the welded part 221 and the adapter piece 3 is small. As a result, the density of each part of the molten pool formed after the adapter piece 3 and the welded part 221 are relatively uniform, the molten pool is not prone to deformation and fracture, and the welding strength and welding quality of the molten pool are ensured.

[0060] If the ratio of the density difference between the welded part 221 and the density of the adapter piece 3 to the density of the adapter piece 3 is greater than 10%, then the density difference between the welded part 221 and the adapter piece 3 is large. In the molten pool formed after the adapter piece 3 and the welded part 221 are welded, the density of the part near the welded part 221 is larger, and the density of the part near the adapter piece 3 is smaller. This results in an excessive density difference between different parts of the molten pool, which leads to insufficient welding strength of the molten pool and makes it prone to deformation and breakage.

[0061] In some embodiments, the adapter piece 3 includes a protrusion 32, which is welded to a welding portion 221. The inner walls of the welding portion 221 and the inner flange portion 223 together define a first space 4, which is used to accommodate the protrusion 32.

[0062] Specifically, the adapter plate 3 also includes a tab welding part 31, which is located on the side of the protrusion 32 away from the terminal post 2. The tab welding part 31 is used to weld to the electrode assembly of the battery.

[0063] The inner walls of the welding part 221 and the inner flange part 223 together define the first space 4, which is used to accommodate the protrusion 32. Thus, the first space 4 provides installation space for the protrusion 32, which facilitates the welding of the protrusion 32 and the welding part 221, and also facilitates the positioning of the electrode assembly and the adapter piece 3 after welding into the housing 1, thereby improving the convenience of the housing process.

[0064] Figure 4 A cross-sectional schematic diagram of the pole post 2 and the sealing nail 5 after connection is shown in an embodiment of this application.

[0065] In some embodiments, the secondary battery further includes a sealing pin 5, and the welding portion 221, together with the inner wall of the main body portion 222 and the outer flange portion 21, defines a second space 6, which is used to accommodate the sealing pin 5, and the sealing pin 5 is connected to the terminal post 2.

[0066] Specifically, the welding part 221, together with the inner wall of the main body part 222 and the outer flange part 21, defines the second space 6. The second space 6 is used to accommodate the sealing nail 5. Thus, the second space 6 provides clearance space for the laser welding of the welding part 221 and the protrusion 32, making it convenient to perform laser welding of the welding part 221 and the protrusion 32 from the outside. At the same time, the second space 6 also provides installation space for the sealing nail 5, so that the sealing nail 5 can be connected to the pole post 2 to seal the top surface of the pole post 2.

[0067] In some embodiments, the hardness range of the welded part 221 is 150HV to 250HV, and the thickness of the welded part 221 is greater than or equal to 0.7mm. This balances the structural strength of the welded part 221 itself with the ease of melting during welding, ensuring that the welded part 221 melts easily during welding and can be quickly welded to the adapter piece 3. Furthermore, the welded part 221 has high strength and is not easily deformed.

[0068] If the hardness of the welded part 221 is less than 150HV, the hardness of the welded part 221 is too small, resulting in insufficient strength and easy deformation; if the hardness of the welded part 221 is greater than 250HV, the hardness of the welded part 221 is relatively large and the strength is relatively strong, but the excessive hardness makes it difficult for the welded part 221 to melt during welding, which is not conducive to the welding process.

[0069] In some embodiments, the secondary battery also includes a sealing ring 7, and the terminal 2 and the housing 1 are sealed together by the sealing ring 7 to ensure the sealing of the connection between the terminal 2 and the housing 1, thereby ensuring the safety of the battery.

[0070] In addition, the sealing ring 7 is made of insulating material to ensure that the pole post 2 is insulated from the housing 1 and to prevent short circuit between the pole post 2 and the housing 1.

[0071] This application also provides an electronic device including a secondary battery of any of the above embodiments.

[0072] Specifically, the electronic devices covered in this application may include, but are not limited to, mobile devices (such as mobile phones, tablets, laptops, video recorders, portable printers / copiers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric toys, electric trains, ships and satellites, spacecraft, energy storage systems, and backup power supplies. Electric toys may include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc. Spacecraft may include airplanes, rockets, and space shuttles, etc.

[0073] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of this application as described above, which are not provided in the details for the sake of brevity.

[0074] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A secondary battery characterized by comprising: include: The housing includes an end wall and a side wall surrounding the end wall, wherein the end wall is provided with a pole post hole; The pole includes an outer flange portion disposed on the outside of the housing and a connecting portion connected to the outer flange portion and passing through the pole hole. The outer flange portion and the connecting portion seal and clamp the end wall to fix the pole. The connecting portion includes a weld portion, and the density of the weld portion is greater than the density of the outer flange portion. The adapter piece is located inside the housing and is welded to the welding part.

2. The secondary battery according to claim 1, characterized by The density of the weld is greater than or equal to 2.7 g / cm 3 , and / or the density of the outer flange portion is greater than or equal to 2.6 g / cm 3 .

3. The secondary battery according to claim 1, characterized by The connecting part further comprises a main body part located in the pole hole, the welding part is integrally formed with the main body part, and the difference between the density of the welding part and the density of the main body part is less than 0.1 g / cm 3 .

4. The secondary battery according to claim 3, characterized by Along the direction from the welded portion to the outer flange portion, the density of the main body portion gradually decreases.

5. The secondary battery according to claim 3, characterized by The connecting portion further includes an inner flange portion, which is located inside the housing and riveted to the end wall. The end of the inner flange portion that connects to the main body portion is the connecting end, and the density of the connecting end is greater than the density of other parts of the inner flange portion except for the connecting end.

6. The secondary battery according to claim 5, characterized by The density of the welded part is greater than the density of the adapter piece, and the ratio of the difference between the density of the welded part and the density of the adapter piece to the density of the adapter piece is less than or equal to 10%.

7. The secondary battery according to claim 5, characterized by The adapter plate includes a protrusion that is welded to the welding portion. The welding portion and the inner wall of the inner flange together define a first space for accommodating the protrusion.

8. The secondary battery according to claim 3, characterized by It also includes a sealing pin, and the inner walls of the welded portion, the main body portion and the outer flange portion together define a second space for accommodating the sealing pin, which is connected to the pole post.

9. The secondary battery according to claim 1, characterized by The hardness range of the welded part is 150HV to 250HV, and the thickness of the welded part is greater than or equal to 0.7mm.

10. An electronic device, comprising: Includes the secondary battery as described in any one of claims 1 to 9.

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